SHAPE MEMORY ALLOY SUB-ASSEMBLIES

Field

The present application relates to sub-assemblies for manufacturing actuator assemblies. Particularly, actuator assemblies comprising shape memory alloy (SMA) wires which are each connected between two coupling elements and deflected around a deflection component.

Background

SMA actuator assemblies are known for use in handheld electronic devices, such as cameras and mobile phones. Such actuator assemblies may be used, for example, in miniature cameras to effect focus, zoom or optical image stabilisation (OIS). By way of example, WO2007/113478 discloses an SMA actuator arrangement for a camera providing autofocus using a single SMA wire and WO2013/175197 discloses a compact SMA actuator arrangement for a camera providing OIS using four SMA wires. Further, W02011/104518 discloses an SMA actuator arrangement comprising eight SMA wires capable of effecting both autofocus and OIS.

WO2016/189314 discloses a method of manufacture of an SMA actuator assembly by first making a sub-assembly in the form of a strut element comprising a sacrificial strut body and crimp portions crimped around the SMA wire under application of a controlled tension, so that the crimp portions hold the SMA wire therebetween. The crimp portions are attached to the static part and the moving part, respectively. Then, the sacrificial strut body is removed, leaving the crimp portions attached to the static part and the moving part, respectively. WO2016/189314 teaches that this provides advantages including the provision of tight control of the length of the SMA wire in the manufactured SMA actuator assembly, because the sacrificial strut body of the strut element holds the relative locations of the crimp portions and thereby maintains the length of the SMA wire therebetween.

WO2021/111131 discloses a shape memory alloy actuator assembly comprising: a support, wherein a first plane is defined with reference to the support; a movable part movable relative to the support along at least two different non-parallel directions in the first plane; plural units of shape memory alloy wire, each unit connected between the movable part and the support so as to be capable of being driven to produce movement in the at least two directions without applying any net torque to the movable part in the first plane; wherein at least one of the units comprises a series of two or more lengths of shape memory alloy wire including a first length and a second length, wherein the first and second lengths are orientated at a non-zero angle relative to each other and are coupled to each other such that, when the unit is driven, contraction of the first length causes a displacement of the second length that provides a contribution to movement of the movable part that is in addition to the contribution provided by contraction of the second length. Provided herein are sub-assemblies for use in manufacturing SMA actuator assemblies such as those described in WO2021/111131, wherein each sub-assembly comprises an SMA wire that is connected between two connectors (e.g. crimps) and that is deflected around a deflection component between the two connectors. Provided herein are also apparatuses for manufacturing these sub-assemblies and methods of manufacturing these sub-assemblies.

Summary of Invention

According to a first aspect of the present invention, there is provided a shape memory alloy (SMA) sub-assembly comprising a unit of SMA wire coupled at a first end to a first connector of the SMA sub-assembly and coupled at a second end to a second connector of the SMA sub-assembly, the unit of SMA wire being deflected around a wire deflection component of the SMA sub-assembly between the first and second ends, and a sacrificial body configured to hold apart the first connector, the second connector and the wire deflection component.

The wire deflection component introduces the deflection in the unit of SMA wire.

Optionally, the unit of SMA wire is held slack between the first and second connectors.

Optionally, the wire deflection component comprises a wire receiving portion for engaging the deflected portion of the unit of SMA wire. The wire receiving portion may (generally or primarily) face away from the first and second connectors. In other words, the wire receiving portion (generally or primarily) may face away from an axis extending between the portions of the first and second connectors coupled to the unit of SMA wire.

Optionally, the wire deflection component (e.g. the wire receiving portion) comprises a curved surface for guiding the deflection of the unit of SMA wire. The curved surface may face away from the first and second connectors. In other words, the curved surface may face away from an axis extending between the portions of the first and second connectors coupled to the unit of SMA wire.

The curved surface may comprise a portion which is parallel to an axis extending between the portions of the first and second connectors which are coupled to the unit of SMA wire, for example, when viewed along an axis perpendicular to the major surface(s) of the sacrificial body. Optionally, the wire deflection component (e.g. the wire receiving portion) comprises a groove for engaging the deflected portion of the unit of SMA wire. The groove may also be for keeping the unit of SMA wire engaged with the wire deflection component.

Optionally, first length of the unit of SMA wire extending between the first connector and the wire deflection component, and a second length of the unit of SMA wire extending between the second connector and the wire deflection component are at an angle to each other.

Optionally, the first length of the unit of SMA wire and the second length of the unit of SMA wire are generally at an angle of 90° to each other, 80° to 100° to each other, or 70° to 110° to each other.

Optionally, the sacrificial body comprises a flexible portion configured to allow relative movement between the wire deflection component and the first and/or second connectors.

Optionally, the wire deflection component comprises a wire guide configured to guide the unit of SMA wire into engagement with the wire deflection component.

The wire deflection component may comprise a wire guide configured to keep the unit of SMA wire in engagement with the wire deflection component.

Optionally, the wire guide is configured to deform to provide a wire retaining channel sized and shaped to slidably or fixedly hold the unit of SMA wire.

Optionally, the wire deflection component comprises a wire retaining channel configure to (e.g. sized and shaped to) slidably or fixedly hold the unit of SMA wire.

Optionally, the first connector comprises a first crimp and/or the second connector comprises a second crimp.

Optionally, the wire deflection component is comprised in or attached to a flexure. The flexure may be capable of flexing (i.e. may be configured to flex) relative to the sacrificial body. The flexure may be capable of flexing (i.e. may be configured to flex) in a plane parallel to the major surface of the sacrificial body.

Optionally, the sacrificial body is configured to hold the first connector, the second connector, and the wire deflection component apart while the first connector, the second connector, and/or the wire deflection component are attached to an SMA actuator assembly. For example, the sacrificial body may be configured to hold the first connector, the second connector, and the wire deflection component apart while the first connector, the second connector, and/or the wire deflection component are attached to a movable part and/or a support structure of an SMA actuator assembly. For example, the sacrificial body may be configured to hold the first connector, the second connector, and the wire deflection component apart while: the first connector is attached to a movable part of an SMA actuator assembly, the second connector is attached to a support structure of the SMA actuator assembly, and the wire deflection component is attached to the movable part and/or the support structure of the SMA actuator assembly.

The sacrificial body may be removable from the first connector, the second connector, and the wire deflection component to leave the unit of SMA wire extending between the attached first and second connectors. And, moreover, leaving the unit of SMA wire deflected around the attached wire deflection component.

According to another aspect of the present invention, there is provided an apparatus (suitable) for manufacturing a shape memory alloy (SMA) sub-assembly (for example, the SMA sub-assembly mentioned above). The SMA sub-assembly comprises a unit of SMA wire coupled at a first end to a first connector of the SMA sub-assembly and coupled at a second end to a second connector of the SMA sub-assembly, the unit of SMA wire being deflected around a wire deflection component of the SMA sub-assembly between the first and second ends, and a sacrificial body configured to hold apart the first connector, the second connector and the wire deflection component. The apparatus comprises: a holding mechanism for holding an actuator blank, the actuator blank comprising the first connector, the second connector, the wire deflection component, and the sacrificial body; a wire positioning mechanism for positioning the unit of SMA wire in relation to the wire deflection component and the first and/or second connectors; a moving mechanism configured to drive relative movement between at least a portion of the unit of SMA wire and the actuator blank so as to introduce the deflection of the unit of SMA wire around the wire deflection component; and a coupling mechanism for coupling the unit of SMA wire to the first and second connectors.

The moving mechanism may be configured to drive the relative movement between the unit of SMA wire and the actuator blank once the unit of SMA wire is positioned in relation to the wire deflection component and the first and/or second connectors.

Optionally, the relative movement driven by the moving mechanism to introduce the deflection of the unit of SMA wire around the wire deflection component also introduces the first end of the unit of SMA wire into the first connector and/or introduces the second end of the unit of SMA wire into the second connector.

Optionally, a first length of the unit of SMA wire extending between the first connector and the wire deflection component, and a second length of the unit of SMA wire extending between the second connector and the wire deflection component are at an angle to each other. In other words, the first and second lengths of the unit of SMA wire are at a non-zero angle relative to each other.

Optionally, the first length of the unit of SMA wire and the second length of the unit of SMA wire are generally at an angle of 90° to each other, 80° to 100° to each other, or 70° to 110° to each other.

Optionally, the moving mechanism is configured to rotate the actuator blank and/or the wire positioning mechanism to introduce the deflection of the unit of SMA wire.

Optionally, the moving mechanism is configured to rotate the actuator blank and/or the wire positioning mechanism, once the first end of the unit of SMA wire has been coupled to the first connector, to introduce the deflection of the unit of SMA wire.

Optionally, the moving mechanism is configured to simultaneously rotate the actuator blank and the wire positioning mechanism (e.g. in the same direction) about a common axis to introduce the deflection of the unit of SMA wire.

Optionally, the wire positioning mechanism is configured to hold the unit of SMA wire between the wire deflection component and either the first or the second connector such that rotation of the actuator blank and/or the wire positioning mechanism by the moving mechanism introduces the deflection of the unit of SMA wire.

In other words, the wire positioning mechanism is configured to hold the unit of SMA wire such that it crosses an axis extending from the wire deflection component to either the first or the second connector such that rotation of the actuator blank and/or the wire positioning mechanism by the moving mechanism introduces the deflection of the unit of SMA wire.

Optionally, the relative movement driven by the moving mechanism between the portion of the unit of SMA wire and the actuator blank is linear when viewed along an axis perpendicular to the major surface of the sacrificial body. Optionally, the apparatus further comprises a wire engaging mechanism configured to be moved by the moving mechanism so that it engages a mid-portion of the unit of SMA wire and moves the midportion of the unit of SMA wire into engagement with the wire deflection component.

Optionally, the moving mechanism is configured to move the actuator blank and/or the wire positioning mechanism.

Optionally, the apparatus further comprises a wire engaging mechanism configured to be moved by the moving mechanism so as to move the second end of the unit of SMA wire to a position where the second end of the unit of SMA wire is held at the second connector and the unit of SMA wire is deflected around the wire deflecting component.

Optionally, the apparatus further comprises a slack addition mechanism for adding slack to the unit of SMA wire.

Optionally, the actuator blank comprises a flexible portion configured to allow relative movement between the wire deflection component and the first and/or second connectors; and the slack addition mechanism is configured to add slack to the unit of SMA wire by driving relative movement between the wire deflection component and the first and/or second connectors (e.g. before and after the unit of SMA wire has been coupled to the first and second connectors).

Optionally, the apparatus further comprises a wire lifting mechanism for lifting the unit of SMA wire over and into the first and second connectors as the moving mechanism drives relative movement between the portion of the unit of SMA wire and the actuator blank.

Optionally, the wire deflection component comprises a wire guide configured to guide the unit of SMA wire into engagement with the wire deflection component; and the apparatus further comprises a deforming mechanism configured to deform the wire guide so as to form a wire retaining channel configured to (i.e. sized and shaped to) slidably or fixedly hold the unit of SMA wire.

The wire deflection component may comprise a wire guide configured to keep the unit of SMA wire in engagement with the wire deflection component; and the apparatus may comprise a deforming mechanism configured to deform the wire guide so as to form a wire retaining channel configured to (i.e. sized and shaped to) slidably or fixedly hold the unit of SMA wire. Optionally, the apparatus further comprises a wire guide mechanism configured to guide the unit of SMA wire into engagement with the wire deflection component.

Optionally, the wire positioning mechanism comprises a first wire holder configured to position a first end of the unit of SMA wire, and a second wire holder configured to position a second end of the unit of SMA wire.

Optionally, the first wire holder is configured to hold the first end of the unit of SMA wire at the first connector when the first end of the unit of SMA wire is coupled to the first connector, and the second wire holder is configured to hold the second end of the unit of SMA wire at the second connector when the second end of the unit of SMA wire is coupled to the second connector.

Optionally, the first connector comprises a first crimp, and the second connector comprises a second crimp; and the coupling mechanism comprises a crimping mechanism for coupling the first and second crimps to the unit of SMA wire by crimping the first and second crimps to the unit of SMA wire.

Optionally, the wire deflection component is comprised in or attached to a flexure. The flexure may be capable of flexing (i.e. may be configured to flex) relative to the sacrificial body. The flexure may be capable of flexing (i.e. may be configured to flex) in a plane parallel to the major surface of the sacrificial body.

According to another aspect of the present invention, there is provided a method of manufacturing a shape memory alloy (SMA) sub-assembly (for example, the SMA sub-assembly mentioned above using the apparatus mentioned above), the SMA sub-assembly comprising a unit of SMA wire coupled at a first end to a first connector of the SMA sub-assembly and coupled at a second end to a second connector of the SMA sub-assembly, the unit of SMA wire being deflected around a wire deflection component of the SMA sub-assembly between the first and second ends, and a (e.g. sacrificial) body configured to hold apart the first connector, the second connector and the wire deflection component. The method includes the steps of: supplying an actuator blank, the actuator blank comprising the first connector, the second connector, the wire deflection component, and the (e.g. sacrificial) body; holding the actuator blank; positioning the unit of SMA wire in relation to the wire deflection component and the first and/or second connectors; driving relative movement between at least a portion of the unit of SMA wire and the actuator blank so as to introduce the deflection of the unit of SMA wire around the wire deflection component; coupling the unit of SMA wire to the first connector; and coupling the unit of SMA wire to the second connector.

The body may be a sacrificial body. The body may be a component configured to hold the first connector, the second connector and the wire deflection component apart.

Optionally, the relative movement driven to introduce the deflection of the unit of SMA wire around the wire deflection component also introduces the first end of the unit of SMA wire into the first connector and/or introduces the second end of the unit of SMA wire into the second connector.

Optionally, the step of driving relative movement between the unit of SMA wire and the actuator blank comprises rotating the actuator blank and/or the wire positioning mechanism.

Optionally, the step of coupling the unit of SMA wire to the first connector happens after the step of positioning the unit of SMA wire and before the step of driving relative movement between the unit of SMA wire and the actuator blank.

Optionally, the step of driving relative movement between the unit of SMA wire and the actuator blank comprises simultaneously rotating the actuator blank and the unit of SMA wire (e.g. in the same direction) about a common axis.

Optionally, the step of coupling the unit of SMA wire to the first connector happens after the step of driving relative movement between the unit of SMA wire and the actuator blank.

Optionally, the step of positioning the unit of SMA wire comprises holding the unit of SMA wire between the wire deflection component and either the first or second connector.

Optionally, the relative movement between the unit of SMA wire and the actuator blank is linear when viewed along an axis perpendicular to the major surface of the (e.g. sacrificial) body.

Optionally, the step of driving relative movement between the unit of SMA wire and the actuator blank comprises using a wire engaging mechanism to engage a mid-portion of the unit of SMA wire and moving the mid-portion of the unit of SMA wire into engagement with the wire deflection component.

Optionally, the step of driving relative movement between the unit of SMA wire and the actuator blank comprises moving the unit of SMA wire and/or the actuator blank after the step of positioning the unit of SMA wire in relation to the wire deflection component and the first and second connectors.

Optionally, the step of driving relative movement between the unit of SMA wire and the actuator blank comprises using a wire engaging mechanism to move the second end of the unit of SMA wire to a position where the second end of the unit of SMA wire is held at the second connector and the unit of SMA wire is deflected around the wire deflecting component.

Optionally, the method further comprises the step of adding slack to the unit of SMA wire.

Optionally, the actuator blank comprises a flexible portion configured to allow relative movement between the wire deflection component and the first and/or second connectors; and the step of adding slack comprises: driving relative movement between the wire deflection component and the first and/or second connectors.

Adding slack by driving relative movement between the wire deflection component and the first and/or second connectors may comprise: moving the flexible portion to a first position (e.g. from a second position), before coupling the unit of SMA wire to the first and second connectors, so as to increase the distance between the wire deflection component and the first and/or second connectors; and then moving the flexible portion to a second position or allowing the flexible portion to move to the second position (e.g. from the first position), after coupling the unit of SMA wire to the first and second connectors, so as to decrease the distance between the wire deflection component and the first and/or second connectors, and thus introduce slack in the unit of SMA wire.

Optionally, the method further comprises the step of deforming a wire guide of the wire deflection component, after the unit of SMA wire has been deflected around the wire deflection component, so as to form a wire retaining channel configured to (i.e. sized and shaped to) slidably or fixedly hold the unit of SMA wire. Optionally, the method further comprises the step of guiding the unit of SMA wire into engagement with the wire deflection component before introducing the deflection of the unit of SMA wire around the wire deflection component.

Optionally, the method further comprises the step of holding the first end of the unit of SMA wire at the first connector when the first end of the unit of SMA wire is coupled to the first connector, and holding the second end of the unit of SMA wire at the second connector when the second end of the unit of SMA wire is coupled to the second connector.

According to another aspect of the present invention, there is provided a SMA sub-assembly made using the above-describe method of manufacturing.

The unit of SMA wire may comprise an electrically insulating coating and the apparatus may further comprise an insulation removal module for selectively removing some or all of the electrically insulating coating at the first and second ends of the unit of SMA wire before the first and second ends are coupled to the first and second connectors. As such, optionally the method further comprises the step of selectively removing some or all of the electrically insulating coating at the first and second ends of the unit of SMA wire before the first and second ends are coupled to the first and second connectors.

Brief Description of the Drawings

Certain embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 is a plan view of a sub-assembly comprising an SMA wire coupled to an actuator blank; Figs. 2, 3 and 4 are schematic plan views of an SMA wire and an actuator blank in successive stages of a method of manufacture;

Figs. 5, 6 and 7 are schematic plan views of an SMA wire and an actuator blank in successive stages of a method of manufacture;

Figs. 8, 9 and 10 are schematic plan views of an SMA wire and an actuator blank in successive stages of a method of manufacture;

Figs. 11, 12 and 13 are schematic plan views of an SMA wire and an actuator blank in successive stages of a method of manufacture;

Figs. 14, 15 and 16 are schematic plan views of an SMA wire and an actuator blank in successive stages of a method of manufacture;

Figs. 17, 18 and 19 are schematic plan views of an SMA wire and an actuator blank in successive stages of a method of manufacture; Figs. 20, 21 and 22 are schematic plan views of an SMA wire and an actuator blank in successive stages of a method of manufacture;

Fig. 23 is a side view of a wire lifter;

Fig. 24 is a perspective view of a wire deflection component comprising a wire guide;

Fig. 25 is a schematic side view of a wire guide;

Fig. 26 is a schematic plan view of a slack adding mechanism;

Fig. 27 is a schematic plan view of a slack adding mechanism;

Fig. 28 is a plan view of a strip of actuator blanks with flexible slack adding portions;

Fig. 29 is a schematic plan view of a strip of actuator blanks;

Fig. 30 is a schematic plan view of a strip of actuator blanks;

Fig. 31 is a schematic plan view of a strip of actuator blanks;

Fig. 32 is a schematic plan view of a strip of actuator blanks; and

Fig. 33 is a plan view of a sub-assembly comprising two units of SMA wire.

Detailed Description

SMA sub-assembly

Fig. 1 is a plan view of a sub-assembly which is herein also referred to as a shape memory alloy (SMA) sub-assembly. The sub-assembly comprises an actuator blank 1 and an SMA wire 10 (herein also referred to as a unit of SMA wire 10). The actuator blank 1 comprises two connectors 21, 22 and a wire deflection component 30. The SMA wire 10 is coupled to the actuator blank 1 via the two connectors 21, 22 and the wire deflection component 30.

The SMA sub-assembly may be used to assemble an SMA actuator assembly comprising an SMA wire that is connected between two connectors (e.g. crimps) and that is deflected around a wire deflection component between the two connectors. For example, the SMA sub-assembly may be used to assemble the SMA actuator assembly described in WO2021/111131.

The first end of the SMA wire 10 is fixedly coupled to the first connector 21 of the actuator blank 1. The first connector 21 is herein also referred to as a first coupling element 21. The second end of the SMA wire 10 is fixedly coupled to the second connector 22. The second connector is herein also referred to as a second coupling element 22. The first and second connectors 21, 22 are mechanically and electrically connected to each other via the SMA wire 10. The midportion of the SMA wire 10 is fixedly or slidably coupled to the wire deflection component 30. The wire deflection component 30 introduces the deflection in the SMA wire 10 around the wire deflection component 30. In other words, the SMA wire 10 is deflected around the wire deflection component 30 between its first and second ends. The SMA wire 10 is held slack between the first and second connectors 21, 22 when the SMA wire 10 is not energized.

The actuator blank 1 comprises a sacrificial body 11. The first connector 21, the second connector 22 and the wire deflection component 30 are fixed to the sacrificial body 11, and are connected to each other via the sacrificial body 11. The sacrificial body 11 holds apart the first connector 21, the second connector 22 and the wire deflection component 30.

During assembly of the SMA actuator assembly, the first connector 21, the second connector 22 and the wire deflection component 30 are attached to parts of the SMA actuator assembly (e.g. the movable and/or support parts of an SMA actuator assembly) while the sacrificial body 11 holds them apart. The first connector 21, the second connector 22 and the wire deflection component 30 are then disconnected from the sacrificial body 11. The sacrificial body 11 is then removed, leaving the first connector 21, second connector 22 and wire deflection component 30 attached to the parts of the SMA actuator assembly. And, moreover, leaving the SMA wire 10 deflected around the attached wire deflection component 30.

The sacrificial body 11 may be configured to hold the first connector 21, the second connector 22, and the wire deflection component 30 apart while the first connector 21, the second connector 22, and/or the wire deflection component 30 are attached to a movable part and/or a support structure of an SMA actuator assembly.

The sacrificial body 11 may be configured to hold the first connector 21, the second connector 22, and the wire deflection component 30 apart while: the first connector 21 is attached to a movable part of an SMA actuator assembly, the second connector 22 is attached to a support structure of the SMA actuator assembly, and the wire deflection component 30 is attached to the movable part and/or the support structure of the SMA actuator assembly.

Having the sacrificial body 11 hold the relative locations of the first connector 21, the second connector 22 and the wire deflection component 30 while they are attached to parts of the SMA actuator assembly is advantageous as it enables the first connector 21, the second connector 22 and the wire deflection component 30 to be easily attached with accurate relative positioning. This helps ensure that no uncontrolled and/or undesired amount of slack addition or removal is introduced to the SMA wire 10, or at least helps minimise this. The sacrificial body 11 may be a thin sheet component made of, for example, phosphor bronze, steel or laminate containing conductive components. The first connector 21, the second connector 22 and/or the wire deflection component 30 may be integrally formed with the sacrificial body 11. The thin sheet component (i.e. the sacrificial body 11 and any part integrally formed with the sacrificial body 11) may be formed by cutting a sheet component, for example, by stamping, etching or laser cutting. The first connector 21, the second connector 22 and/or the wire deflection component 30 may be separate components that are attached to the thin sheet component (i.e. the sacrificial body 11). For example, in Figs. 24 and 25 the wire deflection component 30 is a separate component that is attached to the sacrificial body 11.

The first connector 21 and the second connector 22 may be any type of coupling element suitable for establishing a mechanical and electrical connection with the SMA wire 10. As shown in Fig. 23, the first and second connectors 21, 22 may be crimps.

The wire deflection component 30 may be the 'flexure pulley coupling' described in WO2021/111131 which is incorporated herein by reference. The wire deflection component 30 may be comprised in or attached to a flexure. The flexure may be capable of flexing (i.e. may be configured to flex) relative to the sacrificial body 11. The flexure may be capable of flexing (i.e. may be configured to flex) in a plane parallel to the major surface of the sacrificial body 11.

The first connector 21, the second connector 22 and the wire deflection component 30 each comprise a wire receiving portion configured to receive and hold respective parts of the SMA wire 10. The wire receiving portions of the first connector 21, the second connector 22 and the wire deflection component 30 lie on a common plane (herein also referred to as the SMA wire plane) which is parallel, or at least substantially parallel, to the major surface of the sacrificial body 11.

The wire receiving portion of the wire deflection component 30 is configured to engage the deflected portion of the SMA wire 10. The wire receiving portion of the wire deflection component 30 (generally or primarily) faces away from the first and second connectors 21, 22. In other words, the wire receiving portion of the wire deflection component (generally or primarily) faces away from an axis extending between the portions of the first and second connectors 21, 22 coupled to the SMA wire 10.

The wire deflection component 30 (e.g. the wire receiving portion of the wire deflection component

30) comprises a curved surface for guiding the deflection of the SMA wire 10. The curved surface faces away from the first and second connectors 21, 22. In other words, the curved surface faces away from an axis extending between the portions of the first and second connectors 21, 22 coupled to the SMA wire 10.

The wire deflection component 30 (e.g. the wire receiving portion of the wire deflection component 30) comprises a groove for engaging the deflected portion of the SMA wire 10. The groove may also be for keeping the SMA wire 10 engaged with the wire deflection component 30.

The sacrificial body 11 is rectangular and comprises a central opening which is also rectangular. The first connector 21, the second connector 22 and the wire deflection component 30 are located in the central opening. The first connector 21 is fixed at a first corner of the actuator blank 1. The second connector 22 is fixed at a second corner of the actuator blank 1. The wire deflection component 30 is fixed at a third corner of the actuator blank 1. The first and second corners are diagonally-opposite. The third corner is a corner located between the first and second corners. Although the sacrificial body 11 is rectangular in this example, it may have any suitable shape or form. For example, it may be shaped as shown in Fig. 28.

The SMA wire 10 comprises a first length 10A extending between the first connector 21 and the wire deflection component 30, and a second length 10B extending between the second connector 22 and the wire deflection component 30. When viewed across the SMA wire plane, the notional line extending straight between the wire receiving portions of the first connector 21 and the wire deflection component 30, and the notional line extending straight between the wire receiving portions of the second connector 22 and the wire deflection component 30 are orientated at an angle to each other. In other words, when the SMA wire 10 is taut between the first connector 21 and the second connectors 22, the first length 10A and second length 10B are orientated at an angle to each other when viewed across the SMA wire plane. In this example, the angle is 90° or about 90°. However, the angle may, for example, also be within the range of 80° to 100°, 70° to 110°, or 45° to 135°.

The SMA wire 10 may be made of, for example, Nitinol or another Titanium-alloy SMA material.

Methods of manufacturing the SMA sub-assembly are described below.

First method of manufacturing

A first method of manufacturing the above-mentioned SMA sub-assembly is illustrated in Figs. 2, 3 and 4. Firstly, the actuator blank 1 is fixed to a base plate assembly 91 using a fixing mechanism 93. The fixing mechanism 93 is herein also referred to as a holding mechanism 93. The base plate assembly 91 comprises a moving mechanism M configured to rotate the actuator blank 1 around a rotation axis R which is, at least substantially, perpendicular to the SMA wire plane. In other words, the base plate assembly 91 comprises a moving mechanism M configured to rotate the first connector 21, the second connector 22 and the deflection component 30 around the rotation axis R.

Next, as shown in Fig. 2, a first wire holder 40 is used to hold the first end of the SMA wire 10 at the wire receiving portion of the first connector 21. For example, where the first connector 21 is a first crimp and its wire receiving portion is a pre-formed opening, the first wire holder 40 may be used to hold the first end of the SMA wire 10 within the pre-formed opening of the first connector 21. The first wire holder 40 may be a wire gripper.

Simultaneously, or subsequently, a second wire holder 41 is used to hold a mid-portion of the SMA wire 10 at the wire receiving portion of the wire deflection component 30. The second wire holder 41 may be a wire gripper, a pulley or a roller.

Next, a coupling mechanism 92 is used to couple the first end of the SMA wire 10 to the first connector 21. For example, where the first connector 21 is the first crimp, the SMA wire 10 may be coupled to the first connector 21 by closing the pre-formed opening of the first crimp.

Next, the first wire holder 40 releases the first end of the SMA wire 10 and, as shown in Fig. 3, the moving mechanism is used to rotate the actuator blank 1 around the rotation axis R by a predetermined amount. The actuator blank 1 is rotated such that the SMA wire 10 engages and is deflected around or wrapped around the wire receiving portion of the wire deflection component 30, and the second end of the SMA wire 10 is held at the wire receiving portion of the second connector 22. For example, where the second connector 22 is a second crimp, once the actuator blank 1 has been rotated around the rotation axis R by the predetermined amount, the second wire holder 41 holds the second end of the SMA wire 10 within the wire receiving portion of the second crimp. As with the first crimp, the wire receiving portion of the second crimp may also be a pre-formed opening.

The predetermined amount of rotation shown in Fig. 3 is 90°. However, the actuator blank 1 may instead be over-rotated, i.e. rotated by more than 90°. In the example of Figs. 2 to 4, the wire receiving portion of the first connector 21, the wire receiving portion of the second connector 22 and the wire receiving portion of the wire deflection component 30 have wire receiving openings that face away from the rotation axis R. They also face away from the interior of the sub-assembly. Such wire receiving openings are herein also referred to as outward-facing openings. Where the first connector 21 and the second connector 22 are crimps, the wire receiving openings may be considered to be the pre-formed openings of the crimps.

The wire receiving portion of the wire deflection component 30 may comprise a groove for receiving the deflected portion of the SMA wire 10.

The first connector 21 may instead comprise an inward-facing opening.

The second connector 22 may instead comprise an inward-facing opening. Where this is the case, as shown in Fig. 23, a wire lifter 60 may be used to lift the second end of the SMA wire 10 above the second connector 22 before introducing the SMA wire 10 into the wire receiving opening of the second connector 22. This may involve over-rotating the actuator blank 11 around the rotation axis R (e.g. by 100°) in a first direction and then rotating the actuator blank 11 in a second, opposite direction around the rotation axis R (e.g. by 10°). The over-rotation of the actuator blank 11 would move the SMA wire 10 over and past the wire lifter. The second counter-rotation of the actuator blank 11 would then correct the over-rotation and move the SMA wire 10 into the inward-facing wire receiving opening of the second connector 22.

Next, as shown in Fig. 4, a slack addition mechanism 51, 52 is used to add a controlled amount of slack to the SMA wire 10 extending between the first connector 21 and the second connector 22. During slack addition, the SMA wire 10 is maintained taut in the wire receiving portions of the first connector 21, the second connector 22 and the wire deflection component 30.

In this example, the slack addition mechanism 51, 52 comprises a first slack adder 51 configured to add slack to the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and a second slack adder 52 configured to add slack to the of SMA wire 10 extending between the second connector 22 and the wire deflection component 30. The first and second slack adders 51, 52 may be configured to add slack simultaneously and/or sequentially to the SMA wire 10. Providing separate slack adders for each side may be useful for efficiently adding equal amounts of slack to both the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and the SMA wire 10 extending between the second connector 22 and the wire deflection component 30. In other examples, the slack addition mechanism may instead comprise a single slack adder.

In this example, the slack addition involves moving a pin of the first slack adder 51 against the SMA wire 10 held taut between the first connector 21 and the wire deflection component 30, and moving a pin of the second slack adder 52 against the SMA wire 10 held taut between the second connector 22 and the wire deflection component 30. The pins are moved in a direction perpendicular to the SMA wire plane. However, any other suitable method of adding slack may be used instead. For example, the pins may be moved in any direction to add slack as long as it pushes or pulls the SMA wire 10, hooks may be used to add slack instead of pins, air suction may be used to add slack, and/or the second wire holder 41 may be used to push more amount SMA wire between the first and second connectors 21, 22.

Slack is added by increasing the amount of SMA wire 10 that is held between the first and second connectors 21, 22. It may not be added by elastically or plastically deforming the SMA wire 10. In other words, slack is added by having more SMA wire supplied to the SMA wire 10 extending between the first and second connectors 21, 22. The additional SMA wire may be supplied by e.g. a spool of SMA wire. The second wire holder 41 may be said spool of SMA wire. The second wire holder 41 may be configured to help provide more SMA wire from a spool of SMA wire.

Before using the slack addition mechanism 51, 52 to add slack to the SMA wire 10, the wire deflection component 30 may be provided with a wire retainer configured to ensure that the SMA wire 10 is held within its wire receiving portion during slack addition. For example, as shown in Fig. 24, the wire deflection component 30 may have a tab 70 which may be used as a wire retainer. Before adding slack, the tab 70 may be deformed to provide a wire-retaining channel that is small enough to keep the SMA wire 10 within the wire receiving portion of the wire deflection component 30, but big enough to allow sliding of the wire deflection component 30 within the wire receiving portion of the wire deflection component 30. Said deformation may involve bending the tab 70 over the SMA wire 10. The wire retainer may be a crimp or at least substantially crimp-shaped.

After the desired amount of slack has been added to the SMA wire 10, optionally, the mid-portion of the SMA wire 10 (e.g. the portion of the SMA wire 10 held within the wire receiving portion of the wire deflection component 30) may be fixedly coupled to the wire deflection component 30. Where the wire deflection component 30 is provided with a wire retainer (e.g. tab 70), the wire retainer may be deformed to fixedly hold the mid-portion of the SMA wire 10. Alternatively, the mid-portion of the SMA wire 10 may be fixedly attached to the wire deflection component 30 by any suitable means such as gluing, welding and soldering.

After the desired amount of slack has been added to the SMA wire 10, a coupling mechanism 92 is used to couple the second end of the SMA wire 10 to the second connector 22. For example, where the second connector 22 is the second crimp, the SMA wire 10 may be coupled to the second connector 22 by closing the pre-formed opening of the second crimp. The coupling mechanism 92 used to couple the second end of the SMA wire 10 to the second connector 22 may or may not be the same coupling mechanism 92 used to couple the first end of the SMA wire 10 to the first connector 21.

Until the SMA wire 10 is coupled to both the first and second connectors 21, 22, the slack adders 51, 52 are kept engaged with the SMA wire 10 so as to maintain the SMA wire 10 taut. Once the SMA wire 10 has been coupled to both the first and second connectors 21, 22, the slack adders 51, 52 may be disengaged from the SMA wire 10.

Next, since the SMA wire 10 is supplied by a spool of SMA wire or similar, the second end of the SMA wire 10 is cut and thereby detached from the spool of SMA wire. Before cutting the SMA wire 10, the first wire holder 40 may be used to hold the unused section of the SMA wire (e.g. a portion of the spool of SMA wire adjacent the second end of the unit of SMA wire 10) so that the unused section of the SMA wire is not dropped when the SMA wire 10 is cut. The first wire holder 40 may comprise a wire cutter for cutting the SMA wire 10.

Next, the actuator blank 1, with the SMA wire 10 now coupled to it, is released from the base plate assembly 91. In other words, the completed SMA sub-assembly is released from the base plate assembly 91.

Second method of manufacturing

A second method of manufacturing the above-mentioned SMA sub-assembly is illustrated in Figs. 5, 6 and 7.

Firstly, the actuator blank 1 is fixed to a base plate assembly (not shown) using a fixing mechanism (not shown). The base plate assembly comprises a moving mechanism (not shown) configured to rotate the actuator blank 1 and a first wire holder 40 around a rotation axis R which is, at least substantially, perpendicular to the SMA wire plane. In other words, the base plate assembly comprises a moving mechanism configured to rotate the first connector 21, the second connector 22, the deflection component 30, and a first wire holder 40 around the rotation axis R.

Next, as shown in Fig. 5, the first wire holder 40 is used to hold the first end of the SMA wire 10 at the wire receiving portion of the first connector 21. For example, where the first connector 21 is a first crimp and its wire receiving portion is a pre-formed opening, the first wire holder 40 may be used to hold the first end of the SMA wire 10 within the pre-formed opening of the first connector 21. The first wire holder 40 may be a wire gripper.

Simultaneously, or subsequently, a second wire holder 41 is used to hold a mid-portion of the SMA wire 10 at the wire receiving portion of the wire deflection component 30. The second wire holder 41 may be a wire gripper, a pulley, or a roller.

Next, as shown in Fig. 6, the moving mechanism is used to simultaneously rotate the actuator blank 1 and the first wire holder 40 around the rotation axis R by a predetermined amount. The actuator blank 1 and the first wire holder 40 are rotated such that the SMA wire 10 engages and is deflected around or wrapped around the wire receiving portion of the wire deflection component 30, and the second end of the SMA wire 10 is held at the wire receiving portion of the second connector 22. For example, where the second connector 22 is a second crimp, once the actuator blank 1 and the first wire holder 40 have been rotated around the rotation axis R by the predetermined amount, the second wire holder 41 holds the second end of the SMA wire 10 within the wire receiving portion of the second crimp. As with the first crimp, the wire receiving portion of the second crimp may also be a pre-formed opening.

The predetermined amount of rotation shown in Fig. 6 is 90°. However, the actuator blank 1 may instead be over-rotated, i.e. rotated by more than 90°.

In the example of Figs. 5 to 7, the wire receiving portion of the first connector 21, the wire receiving portion of the second connector 22 and the wire receiving portion of the wire deflection component 30 have wire receiving openings that face away from the rotation axis R. They also face away from the interior of the sub-assembly. These wire receiving openings may be described as outward-facing openings. Where the first connector 21 and the second connector 22 are crimps, the wire receiving openings may be considered to be the pre-formed openings of the crimps.

The wire receiving portion of the wire deflection component 30 may comprise a groove for receiving the deflected portion of the SMA wire 10. The first connector 21 may instead comprise an inward-facing opening.

The second connector 22 may instead comprise an inward-facing opening. Where this is the case, as shown in Fig. 23, a wire lifter 60 may be used to lift the second end of the SMA wire 10 above the second connector 22 before introducing the SMA wire 10 into the wire receiving opening of the second connector 22. This may involve over-rotating the actuator blank 11 around the rotation axis R (e.g. by 100°) in a first direction and then rotating the actuator blank 11 in a second, opposite direction around the rotation axis R (e.g. by 10°). The over-rotation of the actuator blank 11 would move the SMA wire 10 over and past the wire lifter. The second counter-rotation of the actuator blank 11 would then correct the over-rotation and move the SMA wire 10 into the wire receiving opening of the second connector 22.

Next, as shown in Fig. 7, a slack addition mechanism 51, 52 is used to add a controlled amount of slack to the SMA wire 10 extending between the first connector 21 and the second connector 22. During slack addition, the SMA wire 10 is maintained taut in the wire receiving portions of the first connector 21, the second connector 22 and the wire deflection component 30.

In this example, the slack addition mechanism 51, 52 comprises a first slack adder 51 configured to add slack to the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and a second slack adder 52 configured to add slack to the of SMA wire 10 extending between the second connector 22 and the wire deflection component 30. The first and second slack adders 51, 52 may be configured to add slack simultaneously and/or sequentially to the SMA wire 10. Providing separate slack adders for each side may be useful for efficiently adding equal amounts of slack to both the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and the SMA wire 10 extending between the second connector 22 and the wire deflection component 30. In other examples, the slack addition mechanism may instead comprise a single slack adder.

In this example, the slack addition involves moving a pin of the first slack adder 51 against the SMA wire 10 held taut between the first connector 21 and the wire deflection component 30, and moving a pin of the second slack adder 52 against the SMA wire 10 held taut between the second connector 22 and the wire deflection component 30. The pins are moved in a direction perpendicular to the SMA wire plane. However, any other suitable method of adding slack may be used instead. For example, the pins may be moved in any direction to add slack as long as it pushes or pulls the SMA wire 10, hooks may be used to add slack instead of pins, air suction may be used to add slack, and/or the second wire holder 41 may be used to push more amount SMA wire between the first and second connectors 21, 22.

Slack is added by increasing the amount of SMA wire 10 that is held between the first and second connectors 21, 22. It may not be added by elastically or plastically deforming the SMA wire 10. In other words, slack is added by having more SMA wire supplied to the SMA wire 10 extending between the first and second connectors 21, 22. The additional SMA wire may be supplied by e.g. a spool of SMA wire. The second wire holder 41 may be said spool of SMA wire. The second wire holder 41 may be configured to help provide more SMA wire from a spool of SMA wire.

Before using the slack addition mechanism 51, 52 to add slack to the SMA wire 10, the wire deflection component 30 may be provided with a wire retainer configured to ensure that the SMA wire 10 is held within its wire receiving portion during slack addition. For example, as shown in Fig. 24, the wire deflection component 30 may have a tab 70 which may be used as a wire retainer. Before adding slack, the tab 70 may be deformed to provide a wire-retaining channel that is small enough to keep the SMA wire 10 within the wire receiving portion of the wire deflection component 30, but big enough to allow sliding of the wire deflection component 30 within the wire receiving portion of the wire deflection component 30. Said deformation may involve bending the tab 70 over the SMA wire 10. The wire retainer may be a crimp or at least substantially crimp-shaped.

After the desired amount of slack has been added to the SMA wire 10, optionally, the mid-portion of the SMA wire 10 (e.g. the portion of the SMA wire 10 held within the wire receiving portion of the wire deflection component 30) may be fixedly coupled to the wire deflection component 30. Where the wire deflection component 30 is provided with a wire retainer (e.g. tab 70), the wire retainer may be deformed to fixedly hold the mid-portion of the SMA wire 10. Alternatively, the mid-portion of the SMA wire 10 may be fixedly attached to the wire deflection component 30 by any suitable means such as gluing, welding and soldering.

After the desired amount of slack has been added to the SMA wire 10, a coupling mechanism (not shown) is used to couple the first end of the SMA wire 10 to the first connector 21 and couple the second end of the SMA wire 10 to the second connector 22. The coupling mechanism may be configured to couple the first and second connectors 21, 22 simultaneously and/or sequentially. Where the first connector 21 is a first crimp, the SMA wire 10 may be coupled to the first connector 21 by closing the pre-formed opening of the first crimp. Where the second connector 22 is a second crimp, the SMA wire 10 may be coupled to the second connector 22 by closing the pre-formed opening of the second crimp. Alternatively, the first end of the SMA wire 10 may be coupled to the first connector 21 before slack is added to the SMA wire 10, and the second end of the SMA wire 10 may be coupled to the second connector 22 after the desired amount of slack has been added to the SMA wire 10.

Until the SMA wire 10 is coupled to both the first and second connectors 21, 22, the slack adders 51, 52 are kept engaged with the SMA wire 10 so as to maintain the SMA wire 10 taut. Once the SMA wire 10 has been coupled to both the first and second connectors 21, 22, the slack adders 51, 52 may be disengaged from the SMA wire 10.

Next, the first wire holder 40 releases the first end of the SMA wire 10.

Next, since the SMA wire 10 is supplied by a spool of SMA wire or similar, the second end of the SMA wire 10 is cut and thereby detached from the spool of SMA wire. Before cutting the SMA wire 10, the first wire holder 40 may be used to hold the unused section of the SMA wire (e.g. a portion of the spool of SMA wire adjacent the second end of the unit of SMA wire 10) so that the unused section of the SMA wire is not dropped when the SMA wire 10 is cut. The first wire holder 40 may comprise a wire cutter for cutting the SMA wire 10.

Next, the actuator blank 1, with the SMA wire 10 coupled to it, is released from the base plate assembly. In other words, the completed SMA sub-assembly is released from the base plate assembly.

Third method of manufacturing

A third method of manufacturing the above-mentioned SMA sub-assembly is illustrated in Figs. 8, 9 and 10.

Firstly, the actuator blank 1 is fixed to a base plate assembly (not shown) using a fixing mechanism (not shown). The base plate assembly comprises a moving mechanism (not shown) configured to rotate the actuator blank 1 around a rotation axis R which is, at least substantially, perpendicular to the SMA wire plane. In other words, the base plate assembly comprises a moving mechanism configured to rotate the first connector 21, the second connector 22, and the deflection component 30 around the rotation axis R.

Next, as shown in Fig. 8, a first wire holder 40, a second wire holder 41, and a wire support 42 are used to hold the SMA wire 10 in a straight line in the SMA wire plane. The SMA wire 10 is held between the second connector 22 and the wire deflection component 30. The first wire holder 40 may be a wire gripper. The second wire holder 41 may be a wire gripper, a pulley or a roller. The wire support 42 may be a wire gripper, a pulley or a roller.

Next, as shown in Fig. 9, the moving mechanism is used to rotate the actuator blank 1 around the rotation axis R by a predetermined amount. The actuator blank 1 is rotated such that the SMA wire 10 engages and is deflected around or wrapped around the wire receiving portion of the wire deflection component 30, the first end of the SMA wire 10 is held at the wire receiving portion of the first connector 21, and the second end of the SMA wire 10 is held at the wire receiving portion of the second connector 22. In this rotated position, the first wire holder 40 and the wire support 42 hold the first end of the SMA wire 10 at the wire receiving portion of the first connector 21, the second wire holder 41 holds the second end of the SMA wire 10 at the wire receiving portion of the second connector 22, and the SMA wire 10 is deflected around the wire deflection component 30 between the first and second connectors 21, 22.

In this rotated position, where the first connector 21 is a first crimp and its wire receiving portion is a pre-formed opening, the first wire holder 40 and the wire support 42 may hold the first end of the SMA wire 10 within the pre-formed opening of the first connector 21. Similarly, where the second connector 22 is a second crimp and its wire receiving portion is a pre-formed opening, the second wire holder 41 may hold the second end of the SMA wire 10 within the pre-formed opening of the second connector 22.

The wire support 42 is configured to ensure that the first end of the SMA wire 10 is held at the wire receiving portion of the first connector 21. Additionally, the wire support 42 is configured to ensure that the first end of the SMA wire 10 exits the wire receiving portion of the first connector 21 without bending around an edge of the first connector 21 and thus avoid damaging the SMA wire 10. However, the wire support 42 is optional as, for example, one would understand that the wire holder 40 itself may be configured to ensure that the first end of the SMA wire 10 is held at the wire receiving portion of the first connector 21, and configured to ensure that the first end of the SMA wire 10 exits the wire receiving portion of the first connector 21 without bending around an edge of the first connector 21. The wire support 42 may be a wire gripper, a pulley or a roller.

The wire receiving portion of the wire deflection component 30 may comprise a groove for receiving the deflected portion of the SMA wire 10. The predetermined amount of rotation shown in Fig. 9 is 90°. However, the actuator blank 1 may instead be over-rotated, i.e. rotated by more than 90°.

In this example, the wire receiving portion of the first connector 21 and the wire receiving portion of the wire deflection component 30 have wire receiving openings that face away from the rotation axis R. They also face away from the interior of the sub-assembly. The wire receiving openings of the first connector 21 and the wire deflection component 30 may be described as outward-facing openings. The wire receiving portion of the second connector 22, however, has wire receiving openings that face toward the rotation axis R and face toward the interior of the sub-assembly. The wire receiving opening of the second connector 22 may be described as an inward-facing opening. Where the first connector 21 is a first crimp, its wire receiving opening may be considered to be the pre-formed opening of the first crimp. Where the second connector 22 is a second crimp, its wire receiving opening may be considered to be the pre-formed opening of the second crimp.

The first connector 21 may instead comprise an inward-facing opening. Where this is the case, a wire lifter, similar to the wire lifter 60 of Fig. 23, may be used to lift the first end of the SMA wire 10 above the first connector 21 before introducing the SMA wire 10 into the wire receiving opening of the first connector 21. This may involve over-rotating the actuator blank 11 around the rotation axis R (e.g. by 100°) in a first direction and then rotating the actuator blank 11 in a second, opposite direction around the rotation axis R (e.g. by 10°). The over-rotation of the actuator blank 11 would move the SMA wire 10 over and past the wire lifter 60. The second counter-rotation of the actuator blank 11 would then correct the over-rotation and move the SMA wire 10 into the wire receiving opening of the first connector 21.

The second connector 22 may instead comprise an outward-facing opening. Where this is the case, a wire lifter 60 may be used to lift the second end of the SMA wire 10 above the second connector 22 before introducing the SMA wire 10 into the wire receiving opening of the second connector 22. This may involve over-rotating the actuator blank 11 around the rotation axis R (e.g. by 100°) in a first direction and then rotating the actuator blank 11 in a second, opposite direction around the rotation axis R (e.g. by 10°). The over-rotation of the actuator blank 11 would move the SMA wire 10 over and past the wire lifter 60. The second counter-rotation of the actuator blank 11 would then correct the over-rotation and move the SMA wire 10 into the wire receiving opening of the second connector 22. Where this is the case, one would appreciate that the positioning of the second wire holder 41 would be different to that shown in Figs. 8 to 10 to ensure that the second end of the SMA wire 10 is held at the wire receiving portion of the second connector 22. Alternatively or additionally, one would appreciate that a wire support, similar to wire support 42, may be provided. Next, as shown in Fig. 10, a slack addition mechanism 51, 52 is used to add a controlled amount of slack to the SMA wire 10 extending between the first connector 21 and the second connector 22. During slack addition, the SMA wire 10 is maintained taut in the wire receiving portions of the first connector 21, the second connector 22 and the wire deflection component 30.

In this example, the slack addition mechanism 51, 52 comprises a first slack adder 51 configured to add slack to the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and a second slack adder 52 configured to add slack to the of SMA wire 10 extending between the second connector 22 and the wire deflection component 30. The first and second slack adders 51, 52 may be configured to add slack simultaneously and/or sequentially to the SMA wire 10. Providing separate slack adders for each side may be useful for efficiently adding equal amounts of slack to both the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and the SMA wire 10 extending between the second connector 22 and the wire deflection component 30. In other examples, the slack addition mechanism may instead comprise a single slack adder.

In this example, the slack addition involves moving a pin of the first slack adder 51 against the SMA wire 10 held taut between the first connector 21 and the wire deflection component 30, and moving a pin of the second slack adder 52 against the SMA wire 10 held taut between the second connector 22 and the wire deflection component 30. The pins are moved in a direction perpendicular to the SMA wire plane. However, any other suitable method of adding slack may be used instead. For example, the pins may be moved in any direction to add slack as long as it pushes or pulls the SMA wire 10, hooks may be used to add slack instead of pins, air suction may be used to add slack, and/or the second wire holder 41 may be used to push more amount SMA wire between the first and second connectors 21, 22.

Slack is added by increasing the amount of SMA wire 10 that is held between the first and second connectors 21, 22. It may not be added by elastically or plastically deforming the SMA wire 10. In other words, slack is added by having more SMA wire supplied to the SMA wire 10 extending between the first and second connectors 21, 22. The additional SMA wire may be supplied by e.g. a spool of SMA wire. The second wire holder 41 may be said spool of SMA wire. The second wire holder 41 may be configured to help provide more SMA wire from a spool of SMA wire.

Before using the slack addition mechanism 51, 52 to add slack to the SMA wire 10, the wire deflection component 30 may be provided with a wire retainer configured to ensure that the SMA wire 10 is held within its wire receiving portion during slack addition. For example, as shown in Fig. 24, the wire deflection component 30 may have a tab 70 which may be used as a wire retainer. Before adding slack, the tab 70 may be deformed to provide a wire-retaining channel that is small enough to keep the SMA wire 10 within the wire receiving portion of the wire deflection component 30, but big enough to allow sliding of the wire deflection component 30 within the wire receiving portion of the wire deflection component 30. Said deformation may involve bending the tab 70 over the SMA wire 10. The wire retainer may be a crimp or at least substantially crimp-shaped.

After the desired amount of slack has been added to the SMA wire 10, optionally, the mid-portion of the SMA wire 10 (e.g. the portion of the SMA wire 10 held within the wire receiving portion of the wire deflection component 30) may be fixedly coupled to the wire deflection component 30. Where the wire deflection component 30 is provided with a wire retainer (e.g. tab 70), the wire retainer may be deformed to fixedly hold the mid-portion of the SMA wire 10. Alternatively, the mid-portion of the SMA wire 10 may be fixedly attached to the wire deflection component 30 by any suitable means such as gluing, welding and soldering.

After the desired amount of slack has been added to the SMA wire 10, a coupling mechanism (not shown) is used to couple the first end of the SMA wire 10 to the first connector 21 and couple the second end of the SMA wire 10 to the second connector 22. The coupling mechanism may be configured to couple the first and second connectors 21, 22 simultaneously and/or sequentially. Where the first connector 21 is a first crimp, the SMA wire 10 may be coupled to the first connector 21 by closing the pre-formed opening of the first crimp. Where the second connector 22 is a second crimp, the SMA wire 10 may be coupled to the second connector 22 by closing the pre-formed opening of the second crimp.

Alternatively, the first end of the SMA wire 10 may be coupled to the first connector 21 before slack is added to the SMA wire 10, and the second end of the SMA wire 10 may be coupled to the second connector 22 after the desired amount of slack has been added to the SMA wire 10.

Until the SMA wire 10 is coupled to both the first and second connectors 21, 22, the slack adders 51, 52 are kept engaged with the SMA wire 10 so as to maintain the SMA wire 10 taut. Once the SMA wire 10 has been coupled to both the first and second connectors 21, 22, the slack adders 51, 52 may be disengaged from the SMA wire 10.

Next, the first wire holder 40 releases the first end of the SMA wire 10. Next, since the SMA wire 10 is supplied by a spool of SMA wire or similar, the second end of the SMA wire 10 is cut and thereby detached from the spool of SMA wire. Before cutting the SMA wire 10, the first wire holder 40 may be used to hold the unused section of the SMA wire (e.g. a portion of the spool of SMA wire adjacent the second end of the unit of SMA wire 10) so that the unused section of the SMA wire is not dropped when the SMA wire 10 is cut. The first wire holder 40 may comprise a wire cutter for cutting the SMA wire 10.

Next, the actuator blank 1, with the SMA wire 10 coupled to it, is released from the base plate assembly. In other words, the completed SMA sub-assembly is released from the base plate assembly.

Fourth method of manufacturing

A fourth method of manufacturing the above-mentioned SMA sub-assembly is illustrated in Figs. 11, 12 and 13.

Firstly, the actuator blank 1 is fixed to a base plate assembly (not shown) using a fixing mechanism (not shown).

Next, as shown in Fig. 11, a first wire holder 40, a second wire holder 41 and a wire support 42 are used to hold the SMA wire 10 in a straight line in the SMA wire plane. The first end of the SMA wire 10 is held adjacent or at the first connector 21 and the second end of the SMA wire 10 is held adjacent or at the second connectors 22. The first wire holder 40 may be a wire gripper. The second wire holder 41 may be a wire gripper, a pulley or a roller. The wire support 42 may be a wire gripper, a pulley or a roller.

Next, as shown in Fig. 12, a wire deflecting mechanism 61 (herein also referred to as a wire engaging mechanism 61) comprising a hook is used to deflect the mid-portion of the SMA wire 10 into the wire receiving portion of the wire deflection component 30. This is achieved by having the wire deflecting mechanism 61 move the mid-portion of the SMA wire 10 over the wire deflection component 30 and subsequently moving the mid-portion of the SMA wire 10 into the wire receiving portion of the wire deflection component 30. The introduction of the mid-portion of the SMA wire 10 into the wire receiving opening of the wire deflection component 30 may result in unwanted and/or uncontrolled slack being introduced to the SMA wire 10. This unwanted slack may be removed at this stage by, for example, moving the first wire holder 40 away from the actuator blank 11 as or once the wire deflection mechanism 61 is disengaged from the SMA wire 10 so as to maintain the SMA wire 10 taut. The wire deflection mechanism may comprise a wire lifter similar to the wire lifter 60 shown in Fig. 23 in addition to the hook. The hook may be configured to pull the mid-portion of the SMA wire 10 toward the wire deflection component 30 by moving in a plane parallel to the SMA wire plane. The wire lifter may be configured to lift the mid-portion of the SMA wire 10 above and over the wire deflection component 30 as it is pulled by the hook toward the wire deflection component 30.

The above-mentioned deflection of the SMA wire 10 also moves the first end of the SMA wire 10 into the wire receiving portion of the first connector 21, and moves the second end of the SMA wire 10 into the wire receiving portion of the second connector 22. In this deflected position, the first wire holder 40 and the wire support 42 hold the first end of the SMA wire 10 at the wire receiving portion of the first connector 21, the second wire holder 41 holds the second end of the SMA wire 10 at the wire receiving portion of the second connector 22, and the mid-portion of the SMA wire 10 is deflected around or wrapped around the wire receiving portion of the wire deflection component 30.

In this deflected position, where the first connector 21 is a first crimp and its wire receiving portion is a pre-formed opening, the first wire holder 40 and the wire support 42 may hold the first end of the SMA wire 10 within the pre-formed opening of the first connector 21. Similarly, where the second connector 22 is a second crimp and its wire receiving portion is a pre-formed opening, the second wire holder 41 may hold the second end of the SMA wire 10 within the pre-formed opening of the second connector 22.

The wire support 42 is configured to ensure that the first end of the SMA wire 10 is held at the wire receiving portion of the first connector 21. Additionally or alternatively, the wire support 42 is configured to ensure that the first end of the SMA wire 10 exits the wire receiving portion of the first connector 21 without bending around an edge of the first connector 21 and thus avoid damaging the SMA wire 10. However, the wire support 42 is optional as, for example, one would understand that the wire holder 40 itself may be configured to ensure that the first end of the SMA wire 10 is held at the wire receiving portion of the first connector 21, and configured to ensure that the first end of the SMA wire 10 exits the wire receiving portion of the first connector 21 without bending around an edge of the first connector 21.

The wire receiving portion of the wire deflection component 30 may comprise a groove for receiving the deflected portion of the SMA wire 10. In this example, the wire receiving portion of the first connector 21 and the wire receiving portion of the second connector 22 have wire receiving openings that face toward the SMA wire 10 when it is in the pre-deflection position (i.e. before the SMA wire 10 is deflected by the wire deflecting mechanism 61). They also face toward the interior of the sub-assembly. The wire receiving openings of the first connector 21 and the second connector 22 may be described as inward-facing openings. The wire receiving portion of the wire deflection component 30, however, has a wire receiving opening that faces away from the SMA wire 10 when it is in the pre-deflection position, and face away from the interior of the sub-assembly. The wire receiving opening of the wire deflection component 30 may be described as an outward-facing opening. Where the first connector 21 is a first crimp, its wire receiving opening may be considered to be the pre-formed opening of the first crimp. Where the second connector 22 is a second crimp, its wire receiving opening may be considered to be the pre-formed opening of the second crimp.

The first connector 21 may instead comprise an outward-facing opening. Where this is the case, the wire deflection mechanism 61 may comprise a wire lifter, similar to the wire lifter 60 of Fig. 23, for lifting the first end of the SMA wire 10 above the first connector 21 before introducing the first end of the SMA wire 10 into the wire receiving opening of the first connector 21. The introduction of the first end of the SMA wire 10 into the wire receiving opening of the first connector 21 may involve removing any unwanted slack introduced to the SMA wire 10 at this stage by, for example, moving the first wire holder 40 away from the actuator blank 11 as the wire deflection mechanism 61 is disengaged from the SMA wire 10 to maintain the SMA wire 10 taut. Alternatively or in addition to the wire lifter, the hook of the wire deflection mechanism 61 may lift the first end of the SMA wire 10 above the first connector 21.

The second connector 22 may instead comprise an outward-facing opening. Where this is the case, the wire deflection mechanism 61 may comprise a wire lifter, similar to the wire lifter 60 of Fig. 23, for lifting the second end of the SMA wire 10 above the second connector 22 before introducing the second end of the SMA wire 10 into the wire receiving opening of the second connector 22. The introduction of the second end of the SMA wire 10 into the wire receiving opening of the second connector 22 may involve removing any unwanted slack introduced to the SMA wire 10 at this stage by, for example, moving the first wire holder 40 away from the actuator blank 11 as the wire deflection mechanism 61 is disengaged from the SMA wire 10 to maintain the SMA wire 10 taut. Alternatively or in addition to the wire lifter, the hook of the wire deflection mechanism 61 may lift the second end of the SMA wire 10 above the second connector 22. Next, as shown in Fig. 13, a slack addition mechanism 51, 52 is used to add a controlled amount of slack to the SMA wire 10 extending between the first connector 21 and the second connector 22. During slack addition, the SMA wire 10 is maintained taut in the wire receiving portions of the first connector 21, the second connector 22 and the wire deflection component 30.

In this example, the slack addition mechanism 51, 52 comprises a first slack adder 51 configured to add slack to the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and a second slack adder 52 configured to add slack to the of SMA wire 10 extending between the second connector 22 and the wire deflection component 30. The first and second slack adders 51, 52 may be configured to add slack simultaneously and/or sequentially to the SMA wire 10. Providing separate slack adders for each side may be useful for efficiently adding equal amounts of slack to both the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and the SMA wire 10 extending between the second connector 22 and the wire deflection component 30. In other examples, the slack addition mechanism may instead comprise a single slack adder.

In this example, the slack addition involves moving a pin of the first slack adder 51 against the SMA wire 10 held taut between the first connector 21 and the wire deflection component 30, and moving a pin of the second slack adder 52 against the SMA wire 10 held taut between the second connector 22 and the wire deflection component 30. The pins are moved in a direction perpendicular to the SMA wire plane. However, any other suitable method of adding slack may be used instead. For example, the pins may be moved in any direction to add slack as long as it pushes or pulls the SMA wire 10, hooks may be used to add slack instead of pins, air suction may be used to add slack, and/or the second wire holder 41 may be used to push more amount SMA wire between the first and second connectors 21, 22.

Slack is added by increasing the amount of SMA wire 10 that is held between the first and second connectors 21, 22. It may not be added by elastically or plastically deforming the SMA wire 10. In other words, slack is added by having more SMA wire supplied to the SMA wire 10 extending between the first and second connectors 21, 22. The additional SMA wire may be supplied by e.g. a spool of SMA wire. The second wire holder 41 may be said spool of SMA wire. The second wire holder 41 may be configured to help provide more SMA wire from a spool of SMA wire.

Before using the slack addition mechanism 51, 52 to add slack to the SMA wire 10, the wire deflection component 30 may be provided with a wire retainer configured to ensure that the SMA wire 10 is held within its wire receiving portion during slack addition. For example, as shown in Fig. 24, the wire deflection component 30 may have a tab 70 which may be used as a wire retainer. Before adding slack, the tab 70 may be deformed to provide a wire-retaining channel that is small enough to keep the SMA wire 10 within the wire receiving portion of the wire deflection component 30, but big enough to allow sliding of the wire deflection component 30 within the wire receiving portion of the wire deflection component 30. Said deformation may involve bending the tab 70 over the SMA wire 10. The wire retainer may be a crimp or at least substantially crimp-shaped.

After the desired amount of slack has been added to the SMA wire 10, optionally, the mid-portion of the SMA wire 10 (e.g. the portion of the SMA wire 10 held within the wire receiving portion of the wire deflection component 30) may be fixedly coupled to the wire deflection component 30. Where the wire deflection component 30 is provided with a wire retainer (e.g. tab 70), the wire retainer may be deformed to fixedly hold the mid-portion of the SMA wire 10. Alternatively, the mid-portion of the SMA wire 10 may be fixedly attached to the wire deflection component 30 by any suitable means such as gluing, welding and soldering.

After the desired amount of slack has been added to the SMA wire 10, a coupling mechanism (not shown) is used to couple the first end of the SMA wire 10 to the first connector 21 and couple the second end of the SMA wire 10 to the second connector 22. The SMA wire 10 may be coupled to the first and second connectors 21, 22 simultaneously and/or sequentially. Where the first connector 21 is a first crimp, the SMA wire 10 may be coupled to the first connector 21 by closing the pre-formed opening of the first crimp. Where the second connector 22 is a second crimp, the SMA wire 10 may be coupled to the second connector 22 by closing the pre-formed opening of the second crimp.

Alternatively, the first end of the SMA wire 10 may be coupled to the first connector 21 before slack is added to the SMA wire 10, and the second end of the SMA wire 10 may be coupled to the second connector 22 after the desired amount of slack has been added to the SMA wire 10.

Until the SMA wire 10 is coupled to both the first and second connectors 21, 22, the slack adders 51, 52 are kept engaged with the SMA wire 10 so as to maintain the SMA wire 10 taut. Once the SMA wire 10 has been coupled to both the first and second connectors 21, 22, the slack adders 51, 52 may be disengaged from the SMA wire 10.

Next, the first wire holder 40 releases the first end of the SMA wire 10.

Next, since the SMA wire 10 is supplied by a spool of SMA wire or similar, the second end of the SMA wire 10 is cut and thereby detached from the spool of SMA wire. Before cutting the SMA wire 10, the wire holder 40 may be used to hold the unused section of the SMA wire (e.g. a portion of the spool of SMA wire adjacent the second end of the unit of SMA wire 10) so that the SMA wire 10 is not dropped when the SMA wire 10 is cut. The first wire holder 40 may comprise a wire cutter for cutting the SMA wire 10.

Next, the actuator blank 1, with the SMA wire 10 coupled to it, is released from the base plate assembly. In other words, the completed SMA sub-assembly is released from the base plate assembly.

Fifth method of manufacturing

A fifth method of manufacturing the above-mentioned SMA sub-assembly is illustrated in Figs. 14, 15 and 16.

Firstly, the actuator blank 1 is fixed to a base plate assembly (not shown) using a fixing mechanism (not shown).

Next, as shown in Fig. 14, a first wire holder 40 and a second wire holder 41 is used to hold the SMA wire 10 in a straight line in the SMA wire plane. A mid-portion of the SMA wire 10 is held adjacent the wire receiving portion of the wire deflection component 30. The first wire holder 40 may be a wire gripper. The second wire holder 41 may be a wire gripper, a pulley or a roller.

Next, as shown in Fig. 15, the first and second wire holders 40, 41 are moved linearly in the SMA wire plane toward the actuator blank 1 by a moving mechanism (not shown) until the mid-portion of the SMA wire 10 engages and is deflected around the wire receiving portion of the wire deflection component 30, the first end of the SMA wire 10 reaches the wire receiving portion of the first connector 21, and the second end of the SMA wire 10 reaches the wire receiving portion of the second connector 22. In this deflected position, the first wire holder 40 holds the first end of the SMA wire 10 at the wire receiving portion of the first connector 21, the second wire holder 41 holds the second end of the SMA wire 10 at the wire receiving portion of the second connector 22, and the mid-portion of the SMA wire 10 is deflected around or wrapped around the wire receiving portion of the wire deflection component 30. It is worth noting that, alternatively or additionally, the actuator blank 1 may be moved linearly in the SMA wire plane toward the SMA wire 10.

In this deflected position, where the first connector 21 is a first crimp and its wire receiving portion is a pre-formed opening, the first wire holder 40 may hold the first end of the SMA wire 10 within the pre-formed opening of the first connector 21. Similarly, where the second connector 22 is a second crimp and its wire receiving portion is a pre-formed opening, the second wire holder 41 may hold the second end of the SMA wire 10 within the pre-formed opening of the second connector 22.

The wire receiving portion of the wire deflection component 30 may comprise a groove for receiving the deflected portion of the SMA wire 10.

In this example, the wire receiving portion of the first connector 21, the wire receiving portion of the second connector 22, and the wire receiving portion of the wire deflection component 30 have wire receiving openings that face toward the SMA wire 10. They face away from the interior of the subassembly, thus the wire receiving openings of the first connector 21 and the second connector 22 may be described as outward-facing openings. Where the first connector 21 is a first crimp, its wire receiving opening may be considered to be the pre-formed opening of the first crimp. Where the second connector 22 is a second crimp, its wire receiving opening may be considered to be the preformed opening of the second crimp.

The first connector 21 may instead comprise an inward-facing opening. Where this is the case, a wire lifter, similar to the wire lifter 60 of Fig. 23, may be used to lift the first end of the SMA wire 10 above the first connector 21 before introducing the first end of the SMA wire 10 into the wire receiving opening of the first connector 21. This may involve moving the first wire holder 40 in a first direction so as to move the first end of the SMA wire 10 over the first connector 21, and then moving the first wire holder 40 in a second, opposite direction so as to move the first end of the SMA wire 10 into the wire receiving portion of the first connector 21.

The second connector 22 may instead comprise an inward-facing opening. Where this is the case, the wire lifter 60 of Fig. 23, may be used to lift the second end of the SMA wire 10 above the second connector 22 before introducing the second end of the SMA wire 10 into the wire receiving opening of the second connector 22. This may involve moving the second wire holder 41 in a first direction so as to move the second end of the SMA wire 10 over the second connector 22, and then moving the second wire holder 41 in a second, opposite direction so as to move the second end of the SMA wire 10 into the wire receiving portion of the second connector 22.

Next, as shown in Fig. 16, a slack addition mechanism 51, 52 is used to add slack to the SMA wire 10 extending between the first connector 21 and the second connector 22. During slack addition, the SMA wire 10 is maintained taut in the wire receiving portions of the first connector 21, the second connector 22 and the wire deflection component 30. In this example, the slack addition mechanism 51, 52 comprises a first slack adder 51 configured to add slack to the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and a second slack adder 52 configured to add slack to the of SMA wire 10 extending between the second connector 22 and the wire deflection component 30. The first and second slack adders 51, 52 may be configured to add slack simultaneously and/or sequentially to the SMA wire 10. Providing separate slack adders for each side may be useful for efficiently adding equal amounts of slack to both the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and the SMA wire 10 extending between the second connector 22 and the wire deflection component 30. In other examples, the slack addition mechanism may instead comprise a single slack adder.

In this example, the slack addition involves moving a pin of the first slack adder 51 against the SMA wire 10 held taut between the first connector 21 and the wire deflection component 30, and moving a pin of the second slack adder 52 against the SMA wire 10 held taut between the second connector 22 and the wire deflection component 30. The pins are moved in a direction perpendicular to the SMA wire plane. However, any other suitable method of adding slack may be used instead. For example, the pins may be moved in any direction to add slack as long as it pushes or pulls the SMA wire 10, hooks may be used to add slack instead of pins, air suction may be used to add slack, and/or the second wire holder 41 may be used to push more amount SMA wire between the first and second connectors 21, 22.

Slack is added by increasing the amount of SMA wire 10 that is held between the first and second connectors 21, 22. It may not be added by elastically or plastically deforming the SMA wire 10. In other words, slack is added by having more SMA wire supplied to the SMA wire 10 extending between the first and second connectors 21, 22. The additional SMA wire may be supplied by e.g. a spool of SMA wire. The second wire holder 41 may be said spool of SMA wire. The second wire holder 41 may be configured to help provide more SMA wire from a spool of SMA wire.

Before using the slack addition mechanism 51, 52 to add slack to the SMA wire 10, the wire deflection component 30 may be provided with a wire retainer configured to ensure that the SMA wire 10 is held within its wire receiving portion during slack addition. For example, as shown in Fig. 24, the wire deflection component 30 may have a tab 70 which may be used as a wire retainer. Before adding slack, the tab 70 may be deformed to provide a wire-retaining channel that is small enough to keep the SMA wire 10 within the wire receiving portion of the wire deflection component 30, but big enough to allow sliding of the wire deflection component 30 within the wire receiving portion of the wire deflection component 30. Said deformation may involve bending the tab 70 over the SMA wire 10. The wire retainer may be a crimp or at least substantially crimp-shaped.

After the desired amount of slack has been added to the SMA wire 10, optionally, the mid-portion of the SMA wire 10 (e.g. the portion of the SMA wire 10 held within the wire receiving portion of the wire deflection component 30) may be fixedly coupled to the wire deflection component 30. Where the wire deflection component 30 is provided with a wire retainer (e.g. tab 70), the wire retainer may be deformed to fixedly hold the mid-portion of the SMA wire 10. Alternatively, the mid-portion of the SMA wire 10 may be fixedly attached to the wire deflection component 30 by any suitable means such as gluing, welding and soldering.

After the desired amount of slack has been added to the SMA wire 10, a coupling mechanism (not shown) is used to couple the first end of the SMA wire 10 to the first connector 21 and couple the second end of the SMA wire 10 to the second connector 22. The SMA wire 10 may be coupled to the first and second connectors 21, 22 simultaneously and/or sequentially. Where the first connector 21 is a first crimp, the SMA wire 10 may be coupled to the first connector 21 by closing the pre-formed opening of the first crimp. Where the second connector 22 is a second crimp, the SMA wire 10 may be coupled to the second connector 22 by closing the pre-formed opening of the second crimp.

Alternatively, the first end of the SMA wire 10 may be coupled to the first connector 21 before slack is added to the SMA wire 10, and the second end of the SMA wire 10 may be coupled to the second connector 22 after the desired amount of slack has been added to the SMA wire 10.

Until the SMA wire 10 is coupled to both the first and second connectors 21, 22, the slack adders 51, 52 are kept engaged with the SMA wire 10 so as to maintain the SMA wire 10 taut. Once the SMA wire 10 has been coupled to both the first and second connectors 21, 22, the slack adders 51, 52 may be disengaged from the SMA wire 10.

Next, the first wire holder 40 releases the first end of the SMA wire 10.

Next, since the SMA wire 10 is supplied by a spool of SMA wire or similar, the second end of the SMA wire 10 is cut and thereby detached from the spool of SMA wire. Before cutting the SMA wire 10, the wire holder 40 may be used to hold the unused section of the SMA wire (e.g. a portion of the spool of SMA wire adjacent the second end of the unit of SMA wire 10) so that the SMA wire 10 is not dropped when the SMA wire 10 is cut. The first wire holder 40 may comprise a wire cutter for cutting the SMA wire 10. Next, the actuator blank 1, with the SMA wire 10 coupled to it, is released from the base plate assembly. In other words, the completed SMA sub-assembly is released from the base plate assembly.

Sixth method of manufacturing

A sixth method of manufacturing the above-mentioned SMA sub-assembly is illustrated in Figs. 17, 18 and 19.

Firstly, the actuator blank 1 is fixed to a base plate assembly (not shown) using a fixing mechanism (not shown).

Next, as shown in Fig. 17, a first wire holder 40 and a second wire holder 41 is used to hold the SMA wire 10 in a straight line in the SMA wire plane. The second wire holder 41 holds the second end of the SMA wire 10 at the wire receiving portion of the second connector 22, and the first wire holder 40 holds the mid-portion of the SMA wire 10 at or adjacent the wire receiving portion of the wire deflection component 30. Where the second connector 22 is a second crimp and its wire receiving portion is a pre-formed opening, the second wire holder 41 holds the second end of the SMA wire 10 within the pre-formed opening of the second wire holder 41. The second wire holder 41 may be a wire gripper, a pulley or a roller.

Next, as shown in Fig. 18, the first wire holder 40 is rotated around a rotation axis R by a moving mechanism (not shown) such that the SMA wire 10 engages and is deflected around the wire receiving portion of the wire deflection component 30, and the first end of the SMA wire 10 is held at the wire receiving portion of the first connector 21. For example, where the first connector 21 is a first crimp and its wire receiving portion is a pre-formed opening, once the first wire holder 40 has been rotated around the rotation axis R by the predetermined amount, the first wire holder 40 may be used to hold the first end of the SMA wire 10 within the pre-formed opening of the first connector 21. The first wire holder 40 may be a wire gripper.

The predetermined amount of rotation shown in Fig. 3 is 90°. However, the actuator blank 1 may instead be over-rotated, i.e. rotated by more than 90°.

In this example, the wire receiving portion of the first connector 21, the wire receiving portion of the second connector 22 and the wire receiving portion of the wire deflection component 30 have wire receiving openings that face away from the interior of the sub-assembly. These wire receiving openings may be described as outward-facing openings. Where the first connector 21 and the second connector 22 are crimps, the wire receiving openings may be considered to be the preformed openings of the crimps.

The wire receiving portion of the wire deflection component 30 may comprise a groove for receiving the deflected portion of the SMA wire 10.

The second connector 22 may instead comprise an inward-facing opening.

The first connector 21 may instead comprise an inward-facing opening. Where this is the case, a wire lifter, similar to the wire lifter 60 of Fig. 23, may be used to lift the first end of the SMA wire 10 over the first connector 21 before introducing the SMA wire 10 into the wire receiving opening of the first connector 21. This may involve over-rotating the first wire holder 40 around the rotation axis R (e.g. by 100°) in a first direction and then rotating the first wire holder 40 in a second, opposite direction around the rotation axis R (e.g. by 10°). The over-rotation of the actuator blank 11 would move the SMA wire 10 over and past the wire lifter and the first connector 21. The second counter-rotation of the actuator blank 11 would then correct the over-rotation and move the SMA wire 10 into the wire receiving opening of the first connector 21.

Next, as shown in Fig. 19, a slack addition mechanism 51, 52 is used to add a controlled amount of slack to the SMA wire 10 extending between the first connector 21 and the second connector 22. During slack addition, the SMA wire 10 is maintained taut in the wire receiving portions of the first connector 21, the second connector 22 and the wire deflection component 30.

In this example, the slack addition mechanism 51, 52 comprises a first slack adder 51 configured to add slack to the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and a second slack adder 52 configured to add slack to the of SMA wire 10 extending between the second connector 22 and the wire deflection component 30. The first and second slack adders 51, 52 may be configured to add slack simultaneously and/or sequentially to the SMA wire 10. Providing separate slack adders for each side may be useful for efficiently adding equal amounts of slack to both the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and the SMA wire 10 extending between the second connector 22 and the wire deflection component 30. In other examples, the slack addition mechanism may instead comprise a single slack adder. In this example, the slack addition involves moving a pin of the first slack adder 51 against the SMA wire 10 held taut between the first connector 21 and the wire deflection component 30, and moving a pin of the second slack adder 52 against the SMA wire 10 held taut between the second connector 22 and the wire deflection component 30. The pins are moved in a direction perpendicular to the SMA wire plane. However, any other suitable method of adding slack may be used instead. For example, the pins may be moved in any direction to add slack as long as it pushes or pulls the SMA wire 10, hooks may be used to add slack instead of pins, air suction may be used to add slack, and/or the second wire holder 41 may be used to push more amount SMA wire between the first and second connectors 21, 22.

Slack is added by increasing the amount of SMA wire 10 that is held between the first and second connectors 21, 22. It may not be added by elastically or plastically deforming the SMA wire 10. In other words, slack is added by having more SMA wire supplied to the SMA wire 10 extending between the first and second connectors 21, 22. The additional SMA wire may be supplied by e.g. a spool of SMA wire. The second wire holder 41 may be said spool of SMA wire. The second wire holder 41 may be configured to help provide more SMA wire from a spool of SMA wire.

Before using the slack addition mechanism 51, 52 to add slack to the SMA wire 10, the wire deflection component 30 may be provided with a wire retainer configured to ensure that the SMA wire 10 is held within its wire receiving portion during slack addition. For example, as shown in Fig. 24, the wire deflection component 30 may have a tab 70 which may be used as a wire retainer. Before adding slack, the tab 70 may be deformed to provide a wire-retaining channel that is small enough to keep the SMA wire 10 within the wire receiving portion of the wire deflection component 30, but big enough to allow sliding of the wire deflection component 30 within the wire receiving portion of the wire deflection component 30. Said deformation may involve bending the tab 70 over the SMA wire 10. The wire retainer may be a crimp or at least substantially crimp-shaped.

After the desired amount of slack has been added to the SMA wire 10, optionally, the mid-portion of the SMA wire 10 (e.g. the portion of the SMA wire 10 held within the wire receiving portion of the wire deflection component 30) may be fixedly coupled to the wire deflection component 30. Where the wire deflection component 30 is provided with a wire retainer (e.g. tab 70), the wire retainer may be deformed to fixedly hold the mid-portion of the SMA wire 10. Alternatively, the mid-portion of the SMA wire 10 may be fixedly attached to the wire deflection component 30 by any suitable means such as gluing, welding and soldering. After the desired amount of slack has been added to the SMA wire 10, a coupling mechanism (not shown) is used to couple the first end of the SMA wire 10 to the first connector 21 and couple the second end of the SMA wire 10 to the second connector 22. The SMA wire 10 may be coupled to the first and second connectors 21, 22 simultaneously and/or sequentially. Where the first connector 21 is a first crimp, the SMA wire 10 may be coupled to the first connector 21 by closing the pre-formed opening of the first crimp. Where the second connector 22 is a second crimp, the SMA wire 10 may be coupled to the second connector 22 by closing the pre-formed opening of the second crimp.

Alternatively, the first end of the SMA wire 10 may be coupled to the first connector 21 before slack is added to the SMA wire 10, and the second end of the SMA wire 10 may be coupled to the second connector 22 after the desired amount of slack has been added to the SMA wire 10.

Until the SMA wire 10 is coupled to both the first and second connectors 21, 22, the slack adders 51, 52 are kept engaged with the SMA wire 10 so as to maintain the SMA wire 10 taut. Once the SMA wire 10 has been coupled to both the first and second connectors 21, 22, the slack adders 51, 52 may be disengaged from the SMA wire 10.

Next, the first wire holder 40 releases the first end of the SMA wire 10.

Next, since the SMA wire 10 is supplied by a spool of SMA wire or similar, the second end of the SMA wire 10 is cut and thereby detached from the spool of SMA wire. Before cutting the SMA wire 10, the wire holder 40 may be used to hold the unused section of the SMA wire (e.g. a portion of the spool of SMA wire adjacent the second end of the unit of SMA wire 10) so that the SMA wire 10 is not dropped when the SMA wire 10 is cut. The first wire holder 40 may comprise a wire cutter for cutting the SMA wire 10.

Next, the actuator blank 1, with the SMA wire 10 coupled to it, is released from the base plate assembly. In other words, the completed SMA sub-assembly is released from the base plate assembly.

Seventh method of manufacturing

A seventh method of manufacturing the above-mentioned SMA sub-assembly is illustrated in Figs.

20, 21 and 22.

Firstly, the actuator blank 1 is fixed to a base plate assembly (not shown) using a fixing mechanism (not shown). Next, as shown in Fig. 20, a first wire holder 40 and a second wire holder 41 are used to hold the SMA wire 10 in a straight line in the SMA wire plane. The first end of the SMA wire 10 is held at the wire receiving portion of the first connector 21 and the mid-portion of the SMA wire 10 is held at or adjacent the wire receiving portion of the wire deflection component 30. Where the first connector 21 is a first crimp and its wire receiving portion is a pre-formed opening, the first wire holder 40 may be used to hold the first end of the SMA wire 10 within the pre-formed opening of the first connector 21. The first wire holder 40 may be a wire gripper. The second wire holder 41 may be a wire gripper, a pulley or a roller.

Next, as shown in Fig. 21, a wire deflecting mechanism 43 (herein also referred to as a wire engaging mechanism 43) is used to move the SMA wire 10 into engagement with the wire receiving portion of the wire deflection component 30, then deflect the SMA wire 10 around the wire deflection component 30, and finally hold the second end of the SMA wire 10 at the wire receiving portion of the second connector 22. The wire deflecting mechanism 43 may be a pulley configured to be moved linearly in the SMA wire plane by a moving mechanism (not shown). Where the second connector 22 is a second crimp and its wire receiving portion is a pre-formed opening, the wire deflecting mechanism 43 may be used to hold the second end of the SMA wire 10 within the pre-formed opening of the second connector 22.

In this example, the wire receiving portion of the first connector 21, the wire receiving portion of the second connector 22 and the wire receiving portion of the wire deflection component 30 have wire receiving openings that face away from the interior of the sub-assembly. Thus these wire receiving openings may be described as outward-facing openings. Where the first connector 21 and the second connector 22 are crimps, the wire receiving openings may be considered to be the preformed openings of the crimps.

The wire receiving portion of the wire deflection component 30 may comprise a groove for receiving the deflected portion of the SMA wire 10.

The first connector 21 may instead comprise an inward-facing opening.

The second connector 22 may instead comprise an inward-facing opening. Where this is the case, as shown in Fig. 23, a wire lifter 60 may be used to lift the second end of the SMA wire 10 above the second connector 22 before introducing the SMA wire 10 into the wire receiving opening of the second connector 22. This may involve moving the wire deflecting mechanism 43 in a first direction so as to move the second end of the SMA wire 10 over the wire lifter 60 and the second connector 22, and then moving the wire deflecting mechanism 43 in a second, opposite direction so as to move the second end of the SMA wire 10 into the wire receiving portion of the second connector 22.

Next, as shown in Fig. 22, a slack addition mechanism 51, 52 is used to add a controlled amount of slack to the SMA wire 10 extending between the first connector 21 and the second connector 22. During slack addition, the SMA wire 10 is maintained taut in the wire receiving portions of the first connector 21, the second connector 22 and the wire deflection component 30.

In this example, the slack addition mechanism 51, 52 comprises a first slack adder 51 configured to add slack to the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and a second slack adder 52 configured to add slack to the of SMA wire 10 extending between the second connector 22 and the wire deflection component 30. The first and second slack adders 51, 52 may be configured to add slack simultaneously and/or sequentially to the SMA wire 10. Providing separate slack adders for each side may be useful for efficiently adding equal amounts of slack to both the SMA wire 10 extending between the first connector 21 and the wire deflection component 30, and the SMA wire 10 extending between the second connector 22 and the wire deflection component 30. In other examples, the slack addition mechanism may instead comprise a single slack adder.

In this example, the slack addition involves moving a pin of the first slack adder 51 against the SMA wire 10 held taut between the first connector 21 and the wire deflection component 30, and moving a pin of the second slack adder 52 against the SMA wire 10 held taut between the second connector 22 and the wire deflection component 30. The pins are moved in a direction perpendicular to the SMA wire plane. However, any other suitable method of adding slack may be used instead. For example, the pins may be moved in any direction to add slack as long as it pushes or pulls the SMA wire 10, hooks may be used to add slack instead of pins, air suction may be used to add slack, and/or the second wire holder 41 may be used to push more amount SMA wire between the first and second connectors 21, 22.

Slack is added by increasing the amount of SMA wire 10 that is held between the first and second connectors 21, 22. It may not be added by elastically or plastically deforming the SMA wire 10. In other words, slack is added by having more SMA wire supplied to the SMA wire 10 extending between the first and second connectors 21, 22. The additional SMA wire may be supplied by e.g. a spool of SMA wire. The second wire holder 41 may be said spool of SMA wire. The second wire holder 41 may be configured to help provide more SMA wire from a spool of SMA wire. Before using the slack addition mechanism 51, 52 to add slack to the SMA wire 10, the wire deflection component 30 may be provided with a wire retainer configured to ensure that the SMA wire 10 is held within its wire receiving portion during slack addition. For example, as shown in Fig. 24, the wire deflection component 30 may have a tab 70 which may be used as a wire retainer. Before adding slack, the tab 70 may be deformed to provide a wire-retaining channel that is small enough to keep the SMA wire 10 within the wire receiving portion of the wire deflection component 30, but big enough to allow sliding of the wire deflection component 30 within the wire receiving portion of the wire deflection component 30. Said deformation may involve bending the tab 70 over the SMA wire 10. The wire retainer may be a crimp or at least substantially crimp-shaped.

After the desired amount of slack has been added to the SMA wire 10, optionally, the mid-portion of the SMA wire 10 (e.g. the portion of the SMA wire 10 held within the wire receiving portion of the wire deflection component 30) may be fixedly coupled to the wire deflection component 30. Where the wire deflection component 30 is provided with a wire retainer (e.g. tab 70), the wire retainer may be deformed to fixedly hold the mid-portion of the SMA wire 10. Alternatively, the mid-portion of the SMA wire 10 may be fixedly attached to the wire deflection component 30 by any suitable means such as gluing, welding and soldering.

After the desired amount of slack has been added to the SMA wire 10, a coupling mechanism (not shown) is used to couple the first end of the SMA wire 10 to the first connector 21 and couple the second end of the SMA wire 10 to the second connector 22. The SMA wire 10 may be coupled to the first and second connectors 21, 22 simultaneously and/or sequentially. Where the first connector 21 is a first crimp, the SMA wire 10 may be coupled to the first connector 21 by closing the pre-formed opening of the first crimp. Where the second connector 22 is a second crimp, the SMA wire 10 may be coupled to the second connector 22 by closing the pre-formed opening of the second crimp.

Alternatively, the first end of the SMA wire 10 may be coupled to the first connector 21 before slack is added to the SMA wire 10, and the second end of the SMA wire 10 may be coupled to the second connector 22 after the desired amount of slack has been added to the SMA wire 10.

Until the SMA wire 10 is coupled to both the first and second connectors 21, 22, the slack adders 51, 52 are kept engaged with the SMA wire 10 so as to maintain the SMA wire 10 taut. Once the SMA wire 10 has been coupled to both the first and second connectors 21, 22, the slack adders 51, 52 may be disengaged from the SMA wire 10. Next, the first wire holder 40 releases the first end of the SMA wire 10.

Next, since the SMA wire 10 is supplied by a spool of SMA wire or similar, the second end of the SMA wire 10 is cut and thereby detached from the spool of SMA wire. Before cutting the SMA wire 10, the wire holder 40 may be used to hold the unused section of the SMA wire (e.g. a portion of the spool of SMA wire adjacent the second end of the unit of SMA wire 10) so that the SMA wire 10 is not dropped when the SMA wire 10 is cut. The first wire holder 40 may comprise a wire cutter for cutting the SMA wire 10.

Next, the actuator blank 1, with the SMA wire 10 coupled to it, is released from the base plate assembly. In other words, the completed SMA sub-assembly is released from the base plate assembly.

Beneficial features

As shown in Fig. 24, the wire receiving portion of the wire deflection component 30 may comprise a groove shaped and sized to accommodate the SMA wire 10. The groove is herein also referred to as a wire holding groove. The groove extends around an outer side periphery of the wire deflection component 30 in a plane parallel to the SMA wire plane.

As discussed above, the wire deflection component 30 may comprise a tab 70. The tab 70 protrudes from the wire holding groove at an acute angle from the SMA wire plane. The tab 70 is herein also referred to as a wire guide 70 as it can be used to help guide the SMA wire 10 toward the wire receiving portion of the wire deflection component 30.

As discussed above, once the SMA wire 10 has been deflected around the wire deflection component 30, it may be desirable to slidably attach the SMA wire 10 to the wire deflection component 30. Where this is the case, the tab 70 may be bent over the SMA wire 10 in the wire holding groove, without clamping the SMA wire 10, so as to form a wire retaining channel shaped and sized to prevent the SMA wire 10 from jumping out of the wire holding groove. The bending of the tab 70 may be carried out at any stage of the above-described manufacturing processes after the SMA wire 10 has been deflected around the wire deflection component 30.

If, once the SMA wire 10 has been deflected around the wire deflection component 30, it is desirable to fixedly attach the SMA wire 10 to the wire deflection component 30, the tab 70 may be bent over the SMA wire 10 at the wire holding groove so as to clamp the SMA wire 10 to the wire holding groove. The bending of the tab 70 may be carried out at any stage of the above-described manufacturing processes after the SMA wire 10 has been deflected around the wire deflection component 30. Alternatively or additionally, the SMA wire 10 may be fixedly attached to the wire deflection component 30 by, for example, gluing, soldering and/or welding the SMA wire 10 and the wire deflection component 30 together. This, again, may be carried out at any stage of the abovedescribed manufacturing processes after the SMA wire 10 has been deflected around the wire deflection component 30.

Instead of or in addition to tab 70, as shown in Fig. 25, a wire guide mechanism 81 comprising an angled wire guiding surface may be used to help guide the SMA wire 10 into the wire holding groove of the wire deflection component 30 during the relevant stages of the above-described methods of manufacture. In other words, a wire guide mechanism 81 may be used to help guide the SMA wire 10 into engagement with the wire receiving portion of the wire deflection component 30.

Alternatively or additionally, the sacrificial body of the actuator blank 1 may be provided with a wire guide configured to help guide the SMA wire 10 into the wire holding groove of the wire deflection component 30 during the manufacturing steps described above.

Adding slack

Alternatively or additionally, as shown in Fig. 26, slack may be added by moving the slack adders 51, 52 in a plane parallel to the SMA wire plane.

Also, as shown in Fig. 26, a wire support 44 may be provided between the second connector 22 and the slack adder 52 to help ensure that the second end of the SMA wire 10 exits the wire receiving portion of the second connector 22 without bending around an edge of the second connector 22 and thus avoid damaging the second end of the SMA wire 10. Similarly, a wire support may be provided between the first connector 21 and the slack adder 51 to help ensure that the first end of the SMA wire 10 exits the wire receiving portion of the first connector 21 without bending around an edge of the first connector 21 and thus avoid damaging the first end of the SMA wire 10. The wire support 44 may be a pulley or a roller.

Alternatively or additionally, as shown in Fig. 27, slack may be added by using slack adders 151, 152 that rotate in a plane parallel to the SMA wire plane.

Alternatively or additionally, as shown in Fig. 28, the actuator blank 11 may comprise a flexible portion 101 configured to allow relative movement between the wire deflection component 30 and the first and/or second connectors 21, 22; and slack may be added by driving relative movement between the wire deflection component 30 and the first and/or second connectors 21, 22. Adding slack by driving relative movement between the wire deflection component 30 and the first and/or second connectors 21, 22 may comprise: moving the flexible portion 101 to a first position (e.g. from a second position), before coupling the SMA wire 10 to the first and second connectors 21, 22, so as to increase the distance between the wire deflection component 30 and the first and/or second connectors 21, 22; and then moving the flexible portion 101 to a second position or allowing the flexible portion 101 to move to the second position (e.g. from the first position), after coupling the SMA wire 10 to the first and second connectors 21, 22, so as to decrease the distance between the wire deflection component 30 and the first and/or second connectors 21, 22, and thus introduce slack in the SMA wire 10.

The addition of slack is optional when manufacturing the SMA sub-assemblies as slack may be added after the SMA sub-assembly has been manufactured. For example, slack may be added at the stage of attaching the first connector 21, the second connector 22 and the wire deflection component 30 to the relevant parts of the SMA actuator assembly.

In Fig. 28, the flexible portion 101 is a portion of the sacrificial body of the actuator blank 11 which is connected to the wire deflection component 30. However, the flexible portion 101 may instead be a portion of the sacrificial body of the actuator blank 11 which is connected to the first connector 21 and/or the second connector 22. Also, multiple flexible portions similar to flexible portion 101 may be provided to allow said relative movement between the wire deflection component 30 and the first and second connectors 21, 22.

Actuator blanks

As shown in Figs. 28, 29, 30, 31 and 32, multiple actuator blanks may be provided on a single strip. Where this is the case, it may be desirable to provide a dense arrangement of actuator blanks / subassemblies to, for example, minimise material wastage.

Other

At any stage of the above-described manufacturing processes, the SMA wire 10 is kept taut until both the first connector 21 and the second connector 22 are coupled to the first and second ends of the SMA wire 10. This may require that a tensioning mechanism is used to keep the SMA wire 10 taut.

A single subassembly may comprise multiple units of SMA wire each separately connected to the sacrificial body via respective first and second connectors and wire deflection components. For example, as shown in Fig. 33, a single subassembly may comprise a first unit of SMA wire which is coupled to an actuator blank via a first connector, a second connector, and a first wire deflection component; and a second unit of SMA wire which is coupled to the actuator blank via a third connector, a fourth connector, and a second wire deflection component. Any of the above- mentioned manufacturing processes may be used to deflect the second unit of SMA wire around the second wire deflection component and to couple the second unit of SMA wire to the third and fourth connectors.

It will be appreciated that there may be many other variations of the above-described examples.

For example, it will be appreciated that in any of the above-described manufacturing processes, wire supports, similar to the wire support 44 of Fig. 26, may be provided on either or both sides of the first connector 21 to help ensure that the first end of the SMA wire 10 exits the wire receiving portion of the first connector 21 without bending around an edge of the first connector 21 and thus avoid damaging the first end of the SMA wire 10. Such wire supports may also be provided on either or both sides of the second connector 22 to help ensure that the second end of the SMA wire 10 exits the wire receiving portion of the second connector 22 without bending around an edge of the second connector 22 and thus avoid damaging the second end of the SMA wire 10. Such wire supports may also be provided on either or both sides of the slack adder 51, 151 and/or the slack adder 52, 152 to help ensure that the SMA wire 10 is not bent around an edge of the first and/or second connectors 21, 22 and thus avoid damaging the second end of the SMA wire 10.

The predetermined amount of rotation shown in Figs. 3, 6, 9 is 90° given that the first connector 21, the second connector 22 and the wire deflection component 30 are configured to provide an angle of 90° between the first length 10A and the second length 10B of the SMA wire 10. However, it will be appreciated that, for example, the predetermined amount of rotation may instead be 80° where the first connector 21, the second connector 22 and the wire deflection component 30 are configured to provide an angle of 80° between the first length 10A and the second length 10B of the SMA wire 10. It will also be appreciated that the predetermined amount of rotation may instead be, for example, 100° where the first connector 21, the second connector 22 and the wire deflection component 30 are configured to provide an angle of 100° between the first length 10A and the second length 10B of the SMA wire 10. In other words, it will be appreciated that the predetermined amount of rotation depends on the configuration of the first connector 21, the second connector 22 and the wire deflection component 30. It will also be appreciated that multiple SMA wires may be coupled between the first connector 21 and the second connector 22, and bent around the wire deflection component 30.

It will also be appreciated that the amount of slack added by the first slack adder 51, 151 may be different to the amount of slack added by the second slack adder 52, 152.

The manufacturing process illustrated by Figs. 8 to 10 involve holding the SMA wire 10 between the second connector 22 and the wire deflection component 30 in the SMA wire plane, and rotating the actuator blank 11 around the rotation axis R. However, it will be appreciated that the SMA wire 10 may instead be held between the first connector 21 and the wire deflection component 30. It will also be appreciated that alternatively or additionally the SMA wire 10 may be rotated to bend the SMA wire 10 around the wire deflection component 30.