The present application generally relates to apparatus and methods for coupling shape memory alloy (SMA) actuator wires (herein also referred to as SMA wires) to an actuator or actuating component, and in particular to a tool for manufacturing or assembling parts of an actuating module.

There are many types of apparatus in which it is desirable to provide positional control of a movable element. SMA actuator wire is advantageous as an actuator (or part of an actuator/actuating component) because of its high energy density, which means that an actuator comprising SMA actuator wire that is required to apply a particular force can be of a relatively small size.

An example type of apparatus for which SMA actuator wire is used to provide positional control of a movable element is a camera. For example, to achieve focussing, zooming, or shake correction, an actuating component may be used to drive movement of a camera lens element along the optical axis of the camera and/or in a plane orthogonal to the optical axis. In miniature cameras, such as those provided within smartphones, the camera lens element is small and therefore, the actuating component may need to be compact (particularly given space restrictions within smartphones). Consequently, the actuating component must be capable of providing precise actuation over a correspondingly small range of movement. Actuating components that comprise SMA actuator wires may be used to drive movement of such camera lens components. Due to the small size of the moveable element, and the high precision actuation required, the SMA actuator wires may need to be coupled to the actuating component carefully and precisely.

In a first approach of the present techniques, there is provided an apparatus for assembling an actuating module comprising at least one shape memory alloy (SMA) actuator wire, the apparatus comprising: a holder for holding a component of the actuating module to which an SMA wire is to be coupled, the component comprising a pair of coupling elements where a first portion of the SMA wire is couplable to a first coupling element in the pair of coupling elements and a second portion of the SMA wire is couplable to a second coupling element in the pair of coupling elements; an alignment module comprising a rotatable arm for simultaneously (or near simultaneously) guiding the SMA wire to the first and second coupling elements; and a coupling module for simultaneously (or near simultaneously) coupling the SMA wire with each of the first and second crimps to couple the SMA wire to the component.

The pair of coupling elements may be a pair of crimps, the first coupling element may be a first crimp in the pair of crimps, and the second coupling element may be a second crimp in the pair of crimps. The rotatable arm may be for simultaneously (or near simultaneously) guiding the SMA wire into the first and second crimps. The coupling module may be a crimping module for simultaneously (or near simultaneously) closing each of the first and second crimps to couple the SMA wire to the component.

Thus, optionally, there is provided an apparatus for assembling an actuating module comprising at least one shape memory alloy (SMA) wire, the apparatus comprising: a holder for holding a component of the actuating module to which an SMA wire is to be coupled, the component comprising a pair of crimps where a first portion of the SMA wire is couplable to a first crimp in the pair of crimps and a second portion of the SMA wire is couplable to a second crimp in the pair of crimps; an alignment module comprising a rotatable arm for simultaneously (or near simultaneously) guiding the SMA wire into the first and second crimps; and a crimping module for simultaneously (or near simultaneously) closing each of the first and second crimps to couple the SMA wire to the component.

In a second approach of the present techniques, there is provided a method for assembling an actuating module comprising at least one shape memory alloy (SMA) wire, the method comprising: providing, in a holder, a component of the actuating module to which an SMA wire is to be coupled, the component comprising at least a first coupling element and a second coupling element; simultaneously (or near simultaneously) guiding, using an alignment module, a first portion of the SMA wire to the first coupling element and a second portion of the SMA wire to the second coupling element; and simultaneously (or near simultaneously) coupling, using a coupling module, the first coupling element with the first portion of the SMA wire to couple the first portion of the SMA wire to the component, and the second coupling element with the second portion of the SMA wire to couple the second portion of the SMA wire to the component; wherein the guiding step comprises rotating a rotatable arm to guide the wire to the respective coupling elements.

The first coupling element may be a first crimp, the second coupling element may be a second crimp, and the coupling module may be a crimping module. The step of simultaneously (or near simultaneously) guiding may comprise simultaneously (or near simultaneously) guiding, using the alignment module, the first portion of the SMA wire into the first crimp and a second portion of the SMA wire into the second crimp. The step of simultaneously (or near simultaneously) coupling may comprise simultaneously (or near simultaneously) closing, using the crimping module, the first crimp to couple the first portion of the SMA wire to the component, and the second crimp to couple the second portion of the SMA wire to the component. The step of rotating the rotatable arm to guide the wire to the respective coupling elements may comprise rotating the rotatable arm to guide the wire into the respective crimps.

Thus, optionally, there is provided a method for assembling an actuating module comprising at least one shape memory alloy (SMA) wire, the method comprising: providing, in a holder, a component of the actuating module to which an SMA wire is to be coupled, the component comprising at least a first crimp and a second crimp; simultaneously (or near simultaneously) guiding, using an alignment module, a first portion of the SMA wire into the first crimp and a second portion of the SMA wire into the second crimp; and closing, using a crimping module, the first crimp to couple the first portion of the SMA wire to the component, and the second crimp to couple the second portion of the SMA wire to the component, wherein the guiding step comprises rotating a rotatable arm to guide the respective portions of the wire into the respective crimps.

The present techniques also provide a non-transitory data carrier carrying processor control code to implement any of the methods or processes described herein. Implementations of the present techniques will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure la shows a schematic cross-sectional view of a camera apparatus comprising an actuating module with at least one SMA actuator wire;

Figure lb is an isometric view of the camera apparatus of Figure la showing an arrangement of SMA actuator wires;

Figure 2 shows a block diagram of an apparatus for assembling an actuating module comprising at least one shape memory alloy (SMA) actuator wire;

Figure 3a shows a side view of an apparatus for assembling an actuating module comprising at least one SMA actuator wire;

Figure 3b shows a plan view of the apparatus of Figure 3a;

Figure 3c is a plan view of a strip of components to be assembled in the apparatus of Figure 3a;

Figure 3d is an enlarged plan view of part of the strip of Figure 3c;

Figure 4 shows a side view of an insulation removal module of the apparatus of Figure 3a;

Figure 5a shows a view of part of the apparatus of Figure 3a;

Figure 5b shows an enlarged perspective view of components shown in Figure 5a;

Figures 6a, 6c and 6e show enlarged perspective views of an alignment module of Figure 3a in three different positions; Figures 6b, 6d and 6f show enlarged perspective views of a gripper and cutter within the alignment module of each of Figures 6a, 6c and 6e;

Figure 7a is a perspective view of a rotating frame from the apparatus of Figure 3a;

Figure 7b is an enlarged partial cut-away section of the rotating frame in Figure 7a;

Figure 7c is a perspective view of the apparatus of Figure 3a in a rotated position;

Figure 7d is a perspective enlarged view of some components in Figure 7c with other parts of the apparatus removed for ease of viewing the components;

Figures 8a, 8c and 8e show enlarged perspective views of the alignment module of Figure 3a in three different positions;

Figure 8b is an enlarged perspective view of a gripper within the alignment module in the position of Figure 8a;

Figures 8d and 8f show enlarged perspective views of a trap-door within the alignment module of each of Figures 8c and 8e;

Figure 8g is a perspective view of the trap-door of Figure 8d;

Figure 9a is an enlarged perspective view of the apparatus of Figure 3a in another position;

Figure 9b is an enlarged perspective view showing the detail of a slack adding module and crimping module in the apparatus of Figure 9a;

Figure 9c is a partial cut-away view showing detail of the slack adding module and crimping module in the apparatus of Figure 9a; Figure 9d is an enlarged perspective view of components of the slack adding module with other parts of the apparatus removed for ease of viewing the components; and

Figure 10 shows a flow chart of example steps to assemble an actuating module comprising at least one SMA actuator wire.

Broadly speaking, embodiments of the present techniques provide apparatuses and methods for accurate positioning and coupling of a shape memory alloy (SMA) actuator wire to an actuator or actuating component. The apparatus may be manually-operated (i.e. by a human user), partly manually- operated and partly automated, or fully automated.

Merely to assist understanding of how SMA actuator wires may be used to provide precise actuation of a moveable element, an example of an actuating module that uses SMA actuator wires is now described. The example is described in more detail in W02011/104518, the contents of which are herein incorporated by reference. Figure la shows a schematic cross-sectional view of a camera apparatus comprising an actuating module with at least one SMA actuator wire, and Figure lb is a perspective view of the actuating module of Figure la showing an arrangement of SMA actuator wires. The view in Figure la is a cross-sectional view taken along the primary axis P which is the optical axis. The camera apparatus may be incorporated into a portable electronic device such as smartphone or tablet computer. The camera apparatus comprises a support structure 12 supporting an image sensor 40 on which there is an integrated circuit 42. There is a moveable element 11 comprising a camera lens element 41 arranged to focus an image onto the image sensor 40. In some arrangements, the camera apparatus may be a miniature camera in which the camera lens element 41 has one or more lenses with a diameter of at most 10mm. Alternatively, in some arrangements the camera lens may be greater than 10mm.

The moveable element 11 is supported on the support structure 12 by eight SMA actuator wires 1-8. The position of the moveable element 11 relative to the support structure 12 is controlled by varying the temperature of the SMA actuator wires 1-8. Heating is provided directly by a drive current. Cooling is provided by reducing or ceasing the drive current to allow the lens element 41 to cool by conduction, convection and radiation to its surroundings.

Figure lb shows one arrangement in which the SMA actuator wires 1-8 are connected between the support structure 12 and the moveable element 11 by crimping members 50 that crimp the SMA actuator wires 1-8 and are fixed to one of the support structure 12 and the moveable element 11. The crimping members 50 crimp the wire to hold it mechanically, optionally strengthened by the use of adhesive. The crimping members 50 also provide an electrical connection to the SMA actuator wires 1-8. In this arrangement, there are no further flexures or other components to allow moveable element 11 to move in three orthogonal linear directions without requiring gimbals and nested support structures, each dealing with one movement direction. In this example, pairs of the SMA actuator wires 1-8 that are parallel to each other on opposite sides of the moveable element 11 are connected electrically in series by interconnects 51 extending between the crimps 50. It will be appreciated that other arrangements of the crimps and wires may also be used and Figure lb is merely exemplary.

The actuator arrangement may provide optical image stabilisation (OIS) by movement of the camera element laterally of the optical axis as well as movement of a camera lens element along the optical axis. This may reduce the overall size as compared to a camera in which separate actuation arrangements are used to provide OIS and movement of the camera lens element along the optical axis. The actuator arrangement may thus be very compact. Furthermore, the SMA actuator wires 1-8 are themselves very thin, typically of the order of 25pm in diameter, to ensure rapid heating and cooling.

The arrangement of SMA actuator wires 1-8 barely adds to the footprint of the actuator arrangement and may be made very thin in the direction along the optical axis P, since the SMA actuator wires 1-8 are laid essentially in a plane perpendicular to the optical axis P in which they remain in operation. The height along the optical axis then depends on the thickness of the other components such as crimping members and the height necessary to allow manufacture. In practice, it has been found that the actuator arrangement of SMA actuator wires 1-8 shown in Figure lb may be manufactured to a height of about less than 1mm.

As will be understood by a person of skill in the art, assembling the example SMA actuation apparatus shown in Figures la and lb may be difficult, because of the small size of the actuation apparatus, and the precise arrangement of the SMA wires. Accordingly, the present techniques provide a precision manufacturing tool and process for assembling an SMA actuation apparatus.

Turning to Figure 2, this shows a block diagram of an apparatus 100 for assembling an actuating module comprising at least one shape memory alloy (SMA) actuator wire. The apparatus 100 may enable accurate positioning and coupling of a shape memory alloy (SMA) actuator wire to an actuator or actuating component. The apparatus 100 may be manually-operated, partly manually-operated and partly automated, or fully automated.

Generally speaking, the actuating module comprises a component to which an SMA actuator wire is to be coupled. The actuating module may comprise: a support structure, for example, for supporting a moveable component; a moveable platform; an integrated circuit chip or processor for controlling the movement of the actuating module; the moveable element; etc. The term "component to which an SMA actuator wire is to be coupled" is used herein to mean any component of the actuator module to which the SMA wire is to be coupled. The term is used herein to mean that both ends of the SMA actuator wire may be coupled to the same component of the actuator module, or that each end of the SMA actuator wire may be coupled to different components of the actuator module. The term is also used to cover the possibility that both ends of the SMA wire are coupled to a fret having crimps, where the fret is coupled to the actuating module.

The apparatus 100 may comprise an alignment module 106 for guiding an SMA actuator wire into position such that it can be coupled to the correct part of the actuator or actuating component. Each end of a length of SMA actuator wire is coupled to different points on the actuator/actuating component, as shown in the example of Figures la and lb. Accordingly, the alignment module 106 may guide an SMA actuator wire such that a portion of the SMA actuator wire is guided towards and positioned at one coupling site on the actuator, and another portion of the SMA actuator wire is guided towards and positioned at another coupling site on the actuator. In embodiments, each end of an SMA actuator wire may be coupled to the actuator via a crimp or crimping element, which securely fastens the end of the SMA actuator wire to the actuator, while also ensuring a mechanical and electrical connection is made between the SMA actuator wire and the actuator. Thus, the alignment module 106 may guide the SMA actuator wire towards one or more crimps, which is provided at a coupling site on the actuator. The alignment module 106 may be arranged to ensure the SMA actuator wire is held under tension while being coupled to the actuator.

In embodiments, the alignment module 106 may pull an end of SMA actuator wire from a spool of wire (or similar), and guide the SMA actuator wire such that at least one portion of the SMA actuator wire is provided within a crimp of the actuator. In embodiments, the alignment module 106 may guide the SMA actuator wire such that a first portion of the SMA actuator wire is guided towards and provided within a first crimp of the actuator, and a second portion of the SMA actuator wire is guided towards and provided within a second crimp of the actuator. After the SMA actuator wire has been coupled to the first and second crimps, the wire may be cut and thereby detached from the remaining wire on the spool. Before cutting the wire, the unused section of wire may be picked up so that the wire is not dropped (unthreaded from the apparatus) when the wire is cut due to the tension provided by the tensioning device on the wire.

The apparatus may comprise a crimping module 104 to close each crimp/crimping element after the SMA actuator wire is positioned in the pair of crimps. The crimping module 104 may comprise any suitable mechanism to close each crimp. The crimping module 104 may comprise components which are aligned with the coupling sites/location of the crimps on the actuator, such that when the crimping process takes place, the components are in the correct position to close the crimps without touching (and thereby, potentially damaging) any other parts of the actuator. The crimping module 104 may be moveable, e.g. rotatable to assist in ensuring the correct alignment.

Thus, the present techniques provide an apparatus or tool 100 for assembling an actuating module comprising at least one shape memory alloy (SMA) actuator wire, the apparatus comprising: a holder for holding a component of the actuating module to which an SMA actuator wire is to be coupled, the component comprising a pair of crimps where a first portion of the SMA actuator wire is couplable to a first crimp in the pair of crimps and a second portion of the SMA actuator wire is couplable to a second crimp in the pair of crimps; an alignment module comprising a rotatable arm for guiding the SMA actuator wire into the first and second crimps; and a crimping module for simultaneously closing each of the first and second crimps to couple the SMA actuator wire to the component The crimping module 104 and the alignment module 106 may each be caused to operate manually, or one or both of the modules may be automated. It will be understood that the crimping operation only takes place once the SMA actuator wire has been guided into the correct position.

As mentioned above, SMA actuator wires are often used to move small components, such as a lens in a miniature camera of a smartphone. As the components of an actuator may need to be as small as possible, this may result in the SMA actuator wire being located very close to other components of the actuator, camera or smartphone, especially metallic components. If the SMA actuator wire comes into contact with a metal surface that is at a different potential to the SMA actuator wire, then a short circuit may occur. This can cause local heating and/or a spark on the surface of the wire, which can lead to melting and damage of the SMA wire. The SMA wire may become weakened, which may lead to reduced performance or fractures that cause breakage of the wire. Accordingly, it may be desirable to coat or wrap a core of SMA material with a layer of electrically insulating material, to provide an SMA actuator wire that is sufficiently electrically and thermally insulated. In embodiments, the SMA actuator wire may be formed of a core of SMA material that is coated with an electrically insulating layer. The insulating layer may have a thickness in the range of 0.3pm to 10pm (for example of the order of 1pm). The SMA actuator wire may be formed such that the electrically insulating layer is provided along the entire length of the core SMA material. However, achieving good mechanical and electrical contact between the SMA actuator wire and the crimps of the actuator may be hindered by the presence of a relatively thick layer of electrically insulating material. The mechanical action of closing the jaws of the crimp during assembly may not be sufficient to break the electrically insulating layer and thereby, make good contact with the core of SMA material beneath. Thus, in embodiments, the apparatus /tool 100 may comprise an insulation removal module 102, for selectively removing at least one portion of an electrically insulating coating or layer of the SMA actuator wire. The insulation removal module may be arranged to remove portions of the electrically insulating coating of an SMA actuator wire, and in particular, remove portions of the electrically insulating coating corresponding to the portions of SMA actuator wire that are to be coupled to the actuator. The electrically insulating coating may be selectively removed using any suitable technique, such as mechanical abrasion, chemical removal, laser or plasma ablation, or melting of the coating by heating (e.g. using a laser).

Typically, during the assembly process to couple an SMA actuator wire to an actuator, the SMA actuator wire is provided from a spool of wire of known tension. The spools of wire may comprise wire stretched to a known tension, sufficient to prevent further stretching during handling. This also means that once the wire is coupled to the actuator (e.g. via crimps), the wire is taut, as required for controllable actuator operation. However, it may be useful to deliberately add some slack to the SMA actuator wire before it is coupled to the actuator, such that once the wire is coupled to the actuator, the SMA wire is slack rather than taut. It has been found that such slack wires may provide a greater actuator stroke than that of a similar actuator made with taut wires. This is because a longer SMA wire provides greater stroke, so using a longer wire may generally be advantageous, and because the wire from the spool is already under tension, such that it is difficult to stretch the wire any further during operation of the actuator. Thus, in embodiments, the apparatus/ tool 100 may comprise a slack addition module 108. The slack addition module 108 may be arranged to provide a specific, controllable amount of slack or additional length of actuator wire between the coupling sites/crimps.

Various modules and components of the apparatus 100 are now described in more detail with reference to Figures 3a onwards.

Figure 3a shows a side view of an example apparatus 100 for assembling an actuating module comprising at least one SMA actuator wire, and Figure 3b shows a plan view of the apparatus 100 of Figure 3a. As mentioned above, apparatus 100 may enable accurate positioning and coupling of a shape memory alloy (SMA) actuator wire to an actuator or actuating component. The apparatus 100 may be manually-operated, partly manually-operated and partly automated, or fully automated. The example apparatus 100 shown in Figure 3a may be considered to comprise two parts or segments, as indicated by the dashed boxes. The segment on the left hand side of the apparatus 100 as shown in Figure 3a may comprise an insulation removal module 102, while the segment on the right hand side may comprise a crimping module 104. The segment of the apparatus 100 on the right hand side may also comprise an alignment module 106 and/or a slack addition module 108.

As shown in Figure 3c, the crimps may be pre-formed in a strip 300 to be fed into the apparatus 100 in the direction of arrow A on Figure 3b for accurate positioning and coupling of the SMA wire as described in more detail below. The strip 300 is preferably made from a thin sheet metal which may be punched, photo-etched or otherwise manufactured in the desired pattern and features required for crimping and the other functions associated with attaching them to the rest of the actuator and electrical circuit. The strip can be any length according to the handling requirements, production environment and production volumes. For example, for a manually operated apparatus as illustrated in Figure 3a, a strip having 48 crimps may be optimal for manual loading. Alternatively, the strip could be provided on a reel which may be substantially longer, e.g. several kilometres, and the handling may be performed mechanically using typical indexing equipment used in the progression tool industry. In this arrangement, the strip 300 comprises a plurality of frames 302 each having a plurality of indexing features in the form of indentations 304 to assist in alignment as described below. For each frame 302, there are three indentations 304a, 304b aligned along one edge of the frame 302. The three indentations comprise a central indentation 304a equally spaced between a pair of end indentations 304b which are aligned with the end of each frame. It will be appreciated that an end indentation of a first frame will also be the opposed end indentation for an adjacent second frame. Similarly, the positions of the indentations need not be centrally aligned or aligned with the end of the frame but need only be positioned consistently to ensure the correct alignment.

The crimps are aligned transversely across the strip, i.e. the central axis through the acute angle of the wires is perpendicular to the direction of travel of the strip into the apparatus 100. Within each frame 302, there are eight crimps 350a, 350b, 352a, 352b, 354a, 354b, 356a, 356b to provide the desired actuator arrangement, for example within a camera similar to that shown in Figures la and lb. It will be appreciated that the crimps are arranged differently in Figure 3c to those shown in Figure lb but in both designs, the overall arrangement is to achieve 8 wires in a crossed arrangement on each of the four sides.

The eight crimps may be considered to form four pairs of crimps with each pair being joined by a single SMA wire. A first SMA wire (not shown) is held in a first pair of crimps 350b, 352b. As explained in more detail below, the SMA wire is inserted into both crimps by rotating the wire in an clockwise direction. A second SMA wire (not shown) is held in a second pair of crimps 350a, 352a and it will be appreciated that the relative locations of the first and second pair of crimps results in the first and second SMA wires crossing. As explained in more detail below, the second SMA wire is inserted into both crimps by rotating the wire in the opposite direction to the first SMA wire, i.e. in a clockwise direction.

Figure 3d is a close-up view of the third and fourth pair of crimps from the frame in Figure 3c. Alternatively, these pairs of crimps may be considered to be the first and second pairs of crimps for a second component. As shown the third pair of crimps 354a, 356a are joined by an SMA wire 305a and a fourth pair of crimps 354b, 356b are joined by a separate SMA wire 305b so that the SMA wires 305a, 305b cross over each other. The two pairs of crimps with crossing wires and the supporting structure may be termed a fret or actuating module/component. Figure 3d also illustrates the direction of rotation of the wires into the pairs of crimps.

Returning to Figure 3c, each set of four crimps are attached to the frame 302 using a tab 310a, 310b, 310c, 310d which may be used to facilitate attachment of the crimps and SMA wires to an assembly such as that shown in Figure lb and may be removed after assembly. Each tab 310a, 310b, 310c, 310d has between one and four small holes to indicate to which of the four sides of the assembly in Figure lb, the tab is to be attached. In this arrangement, a first frame has the tabs 310a, 310d for the first and fourth sides of the assembly and a second frame has the tabs 310b, 310c for the second and third sides of the assembly. Each tab comprises four crimps and two wires and depending on the design there may be minor differences in the relative locations of the crimps and other minor features which are different on each side. For example, in this arrangement each of the upper crimps 350a, 350b, 354a, 354b is also attached to a second tab 312 which is removed after the wire is attached. As shown in Figure 3c, the second tabs 312 are in different locations relative to the crimps in the frame having the first and fourth tabs and the frame having the scond and third tabs. Each pair of crimps may be considered to be a component of an actuating module. Other parts of the component may be removed after assembly as required.

In the arrangement of Figure 3c, the multiple pairs of crimps may be mirror images of one another. By patterning multiple pairs of adjacent crimps as shown in Figure 3c, spacing and height may be consistent on each side and the same punch tools may be used to perform the closing of the crimps in both pairs. In this arrangement, each frame comprises eight crimps and there may be six frames in each strip for manual loading. Furthermore, as explained in more detail below, the arrangement allows the crimps to be assembled with wire from a single spool. Alternatively, the geometry that provides optimal performance in the actuator assembly may require the pairs of crimps to be asymmetric, e.g. with the first pair of crimps being closer to one another than the second pair of crimps and so on. Furthermore, the crimps may be rotated on the actuator assembly so that the axis bisecting the acute angle is not horizontal within the final actuator. Alternatively, other features of the design, such as mounting structures or electrical terminals may result in eight individual crimps. This may require adaptation of the punching tools to accommodate variations in the crimps. Alternatively, it may be necessary to use more than one spool of wire to feed into such asymmetric crimps. Variability in wire production means that there may be challenges to achieve sufficient consistency in wire performance if more than one spool of wire is used.

Figure 4 shows a side view of the insulation removal module 102 of the apparatus 100 of Figure 3a. As mentioned above, the SMA actuator wire used to provide or assemble an actuating module may be formed of a wire having a core of SMA material that is coated with an electrically insulating layer. The insulating layer may have a thickness in the range of 0.3pm to 10pm. The SMA actuator wire may be formed such that the electrically insulating layer is provided along the entire length of the core SMA material. As mentioned earlier, to enable a good mechanical and electrical connection between the SMA actuator wire and the component(s) of the actuating module to which the SMA actuator wire is to be coupled, it may be useful to remove portions of the electrically insulating coating. Specifically, it may be useful to selectively remove all or part of the electrically insulating coating at the point(s) on the wire which will be coupled to the component(s) of the actuating module. For example, if a length of SMA actuator wire is to be coupled to two crimps, which are a fixed, known distance apart, then the insulation removal module 102 may be arranged to remove (all or part of) the electrically insulating coating from two points on the SMA actuator wire, where the two points are separated by substantially the same distance as the distance between the two crimps. Accordingly, when the electrically insulating coating has been removed from two points on an SMA actuator wire, the alignment module 106 of the apparatus 100 may guide the SMA actuator wire such that the two points are aligned with the two components of the actuating module to which the SMA actuator wire is to be coupled (e.g. the two crimps).

It will be understood that the separation of the two points on the SMA actuator wire where the insulating coating is (partly or completely) removed may depend on, for example, the precise arrangement of the actuator wire, the structure of the actuating module, and/or whether any slack is to be added to the wire. It is important to ensure that a precise length of SMA wire is provided between the crimping elements.

As described in relation to Figure 3a, a single piece of SMA wire may be provided between each pair of crimping elements. Here, the length of SMA wire between the two points on the SMA actuator wire where the insulating coating is removed needs to be at least the same as the distance between the pair of crimping elements. In embodiments where slack is added to an SMA wire before it is coupled to the crimping elements, the length of SMA wire provided between the crimping elements may need to be substantially equal to the distance plus a fixed amount (predetermined/predefined amount) of slack length. The distance between a pair of crimps may be between 5 to 20mm and the width of each crimp may be between 300 to 800 pm. The amount of slack may be between 30 to 200 pm. Removing the insulation may weaken the wire and thus the locations and amount of the insulation removal need to be carefully controlled to keep them as small as possible but accurately aligned with the distance between the crimps. To account for variations in alignment, more insulation may be removed than is needed to match the width of the crimps. Thus when the wire is held in the crimps, there may be small (e.g. 200 to 400 pm) portions of the wire on either or both sides of the crimps which has no coating. Nevertheless, there is a section of wire between the crimps which is still coated.

The insulation removal module 102 may be arranged to remove (all or part of) the electrically insulating coating at a particular point along an SMA actuator wire, by using any suitable technique, such as mechanical abrasion, chemical removal, laser or plasma ablation, or by melting the coating (e.g. using a laser). To achieve a good mechanical and electrical connection, it may not be necessary to completely remove all of the electrically insulating coating.

In the embodiment shown in Figure 4, the insulation removal module 102 comprises two lasers 400, and a component 404 for holding an SMA actuator wire in position during the insulation removal process. The two lasers 400 may be used to remove (all or part of) the electrically insulating coating at two points along the SMA actuator wire. The two lasers 400 may simultaneously emit a laser beam to remove all or part of the electrically insulating coating, or each laser may be operated in turn. Preferably, the two lasers 400 are of the same type (e.g. the same power and wavelength), so that two lasers 400 remove the electrically insulating coating in the same manner. The two lasers 400 may be used to ablate the electrically insulating coating off the core SMA material at the two points along the SMA actuator wire. Alternatively, the two lasers 400 may be used to melt all or part of the electrically insulating coating off the core SMA actuator material at the two points along the SMA actuator wire. The melting may disperse or displace enough of the electrically insulating coating such that a good electrical connection to the core SMA material is possible. The two lasers 400 may be positioned such that the two laser beams are directed to two points on the SMA actuator wire that are separated by the same distance as the distance between the two crimps to which the SMA actuator wire is to be coupled. Optical elements may be used to adjust the path of one or both laser beams to enable the correct positioning of the beams relative to the SMA actuator wire.

It will be understood that the insulation removal module 102 could, in embodiments, comprise a single laser instead of two lasers 400. A laser beam from the single laser could be split into two beams, preferably of the same or substantially the same power. Thus, in embodiments, the insulation removal module 102 may comprise a beam splitter to provide the two beams. The insulation removal module 102 may further comprise optical elements to direct each beam to the correct positions along the SMA actuator wire as the wire is held in position by component 404. In the two laser and single laser embodiments described above, the SMA actuator wire is held in place by component 404 during the insulation removal process, and then may be pulled out of component 404 and guided towards the crimps by the alignment module 106. Alternatively, the insulation removal module 102 may comprise a single laser and a means for moving the SMA actuator wire relative to a laser beam of the single laser. In this way, a single laser and a single beam could be used to remove the insulating coating from the SMA actuator wire. In this embodiment, the laser may be turned on to remove the insulating coating from a first point along the SMA actuator wire, and then may be turned off (or the beam may be blocked by a shutter or otherwise) while the SMA actuator wire is moved such that a second point will be in the beam path when the laser is turned back on (or the shutter opened), where the first point and second point are separated by a distance substantially equal to the distance between the two crimps to which the SMA actuator wire is to be coupled. The laser may be turned on (or the shutter opened) to remove the insulating coating from the second point, and then turned off/blocked. An alternative arrangement may comprise a single laser and a directing apparatus such as a galvanometer controlled mirror to direct the laser to different parts of the wire.

Thus, in embodiments, the apparatus 100 may comprise an insulation removal module 102 for selectively removing at least one portion of an electrically insulating coating around the SMA actuator wire. The insulation removal module may comprising a laser for selectively removing at least some of the at least one portion of the electrically insulating coating. As mentioned above, it may be sufficient to remove at least some of the insulating coating to achieve a good electrical and mechanical connection between the SMA actuator wire and the actuating module. At least some of the insulating coating may be removed if heat (e.g. provided by the laser) is used to melt the insulating coating, while substantially all of the insulating coating may be remove if laser ablation is employed. Thus, the laser may selectively remove at least some of the at least one portion of the electrically insulating coating by one of laser ablation or melting of the electrically insulating coating. A first portion of the SMA actuator wire may be couplable to a first crimp, and a second portion of the SMA actuator wire may be couplable to a second crimp, where the first crimp and second crimp are separated by a fixed distance, and where the insulation removal module 102 may be configured to selectively remove some or all of the electrically insulating coating at the first portion and the second portion of the SMA actuator wire. The first portion and the second portion may be separated by a length of SMA actuator wire that is at least the same length as the fixed distance between the first and second crimps.

The insulation removal module 102 may comprise a stage for positioning the SMA actuator wire relative to the laser, such that a beam emitted by the laser is directed to the first portion of the SMA actuator wire. The insulation removal module may comprise movement means for moving the stage by a distance equal to the fixed distance, such that the beam emitted by the laser is directed to the second portion of the SMA actuator wire. While the movement occurs, the laser may be switched off or may be blocked. The stage may be a translation stage and the movement means may be a micrometer adjuster. The micrometer adjuster may be manual or motorised. For example, the micrometer adjuster may be automatically controlled to move the translation stage after the electrically insulative coating has been removed from the first portion, or a duration of time has elapsed which is determined to be sufficient to remove the coating.

Alternatively, the insulation removal module 102 may comprise a first laser beam for selectively removing at least some of a first portion of the electrically insulating coating of the SMA actuator wire, and a second laser beam for selectively removing at least some of a second portion of the electrically insulating coating of the SMA actuator wire. The first laser beam and second laser beam may be provided by, respectively, a first laser and a second laser, or may be provided by a single laser beam from a single laser that is split into two or more beams. Here, the first portion of the SMA actuator wire may be couplable to a first crimp, and the second portion of the SMA actuator wire may be couplable to a second crimp, where the first crimp and second crimp may be separated by a fixed distance, and where the first portion and the second portion are separated by a length of SMA actuator wire that is at least the same length as the fixed distance between the first and second crimps.

Alternatively, the insulation removal module 102 may comprise a laser and one or more optical elements arranged to split a beam emitted by the laser into a first laser beam and a second laser beam, and to direct the first and second laser beams towards, respectively, a first portion and a second portion of the SMA actuator wire.

The insulation removal module 102 may, for safety reasons, be contained within a container or box 410. This may be particularly important where one or more lasers are used to perform the insulation removal process. The container 410 may comprise a door 406 (with a handle 408), to allow access to the wire and lasers 400, and to prevent access for safety reasons when the lasers are in operation (for example).

In embodiments where the apparatus 100 comprises an insulation removal module 102, the prepared SMA actuator wire is pulled out of the insulation removal module 102 and towards the crimps to which the SMA actuator wire is to be coupled, by the alignment module 106. However, it will be understood that in some embodiments, the SMA actuator wire may be prepared elsewhere or may be received ready-prepared/ready-to-use, and in this case, the alignment module 106 may pull the SMA actuator wire from a spool or from another source/location. For example, in embodiments, the electrically insulating coating may be selectively applied to the core SMA material, such that selective removal is not required. In this case, the insulation removal module 102 may not be required.

However the SMA actuator wire is prepared, the alignment module 106 is used to direct the SMA actuator wire to the coupling sites on the actuating module. Figure 5a shows a view of a crimping module 104 and an alignment module 106 of the apparatus of Figure 3a. The crimping module 104 and alignment module 106 may be provided as part of a die tool set. The die tool set comprises a die tool top 514 and a die tool base 516. Components of the crimping module 104 and alignment module 106 may be coupled to the die tool top 514 and/or the die tool base 516. The die tool base 516 may be static in a vertical direction, while the die tool top 514 may be moveable in a vertical direction. The die tool set may comprise a handle or lever 500 for moving the die tool top 514. Moving the lever 500 (in the directions indicated by arrow A) may cause the die tool top 514 to move in the directions indicated by arrow B. Thus, the die tool top 514 can be moved closer to the die tool base 516 by operation of lever 500.

The alignment module 106 may be capable of moving in three dimensions in order to accurately guide an SMA actuator wire into the crimp(s). The alignment module may be capable of moving in the x direction (i.e. parallel to the axis of SMA wire), so that the alignment module can pick up an end of the SMA wire and pull the wire towards the crimps. The alignment module 106 may be capable of moving in the y direction (i.e. perpendicular to the axis of the SMA wire, or in an up-down direction), so that the alignment module can raise and lower the SMA actuator wire as it is being moved towards the crimps. The alignment module 106 may be capable of moving in the z direction (i.e. perpendicular to the axis of the SMA wire, or along the axis of the strip), so that the alignment module can push an SMA wire into a crease or fold of the crimps (as explained in more detail below). The movements of the alignment module 106 in each dimension are carefully controlled to enable the SMA wire to be positioned accurately.

As shown in more detail in Figure 5b, the alignment module 106 may comprise a gripper 504 for gripping an end of the prepared SMA actuator wire 505, and a guide plate 502 for moving the gripper 504 between a number of defined positions. The guide plate 502 may comprise four notches or grooves A, B, C and D. The alignment module may comprise a pin 503 or handle which is provided within the guide plate 502 such that movement of the pin/handle in the guide plate effects movement of the alignment module 106 (and specifically the gripper 504) as described in more detail in relation to Figures 6a to 6f. In Figures 6a to 6f, the change in position of components as the pin is set in each of notches A to C is described. As described in more detail below, the order of the notches on the guide plate is not necessarily related to the order in which the pin is set in these notches. The alignment module 106 may also comprise an indexing system to transport the strip 300 having the crimps through the apparatus. The indexing system comprises a bridge 530 which extends across the apparatus in the z- direction and which has a shallow groove 532 within which the strip 300 is housed. The indexing system further comprises a lever 534 which is located to one side of the bridge 530. The lever 534 is moveable between a first position in which the strip 300 is free to slide in the z-direction along the groove 532 and a second position in which a projection 536 (which may also be termed a pawl) on the lever 534 engages with the indexing indentations (which may also be termed notches) on the side of the strip 300. The engagement of the projection 536 in an end indentation accurately positions a first set of crimps in each frame and the engagement of the projection 536 in the central indentation accurately positions a second set of crimps in each frame. For example, the crimps may be positioned over anvils as explained below. The bridge may be considered to be a holder for holding the strip and the lever may be considered to be part of the holder too.

In this arrangement, the lever 534 may be biased in the second position and thus an operator must actuate the lever 534 to release the projection 536 from the indexing indentation. Once the strip is free to move, the operator may push the strip forward to the next crimp set, e.g. the third and fourth pair of crimps in the frame, if the first crimp set, e.g. the first and second pair of crimps in the frame, was previously manufactured or the next frame if both crimp sets within a frame have been completed. When the operator releases the lever 534, the lever 534 returns to the second position whereby the projection 536 engages with the indentation and centres the alignment.

It will be appreciated that this is just one example of a suitable indexing system and other similar systems could be used. For example, indexing pins may be used to move the strip forward, pins through holes to finalise the position or any of the existing technologies for handling continuous webs of sheet metal. Figures 6a to 6f illustrate the different configurations for the alignment module (and other components in the apparatus) when the pin 503 is in three of the four notches or grooves A, B and C in the guide plate 502. The pin 503 extends from an arm 600 which supports the gripper 504. The notches are fixed locations in a cam slot and by sliding the pin 503 along the cam slot from one notch to an adjacent slot, the arm 600 is along moved. Figures 6a and 6b show a 'storage' position position when the pin 503 is in notch A which is the leftmost notch in this configuration. In this position, the gripper 504 is moved out of the way, for example for when the device is being serviced or is not in use. The gripper 504 is positioned to one side of the channel 532, the left side as illustrated in this configuration.

Figures 6c and 6d show a first 'pick-up' position in which the pin 503 is in notch B in the guide plate 502. Notch B is adjacent to notch A and notches A and B are set at approximately the same height and thus the arm 600 is set at the same height relative to the bridge in both positions. In this position, the gripper 504 is angled relative to the channel 532 and the bridge 530, in other words, the axis of the gripper 504 is not parallel to the axis along the channel 532 and the bridge 530. The angle is created by rotation using the rotating frame shown in Figure 7a.

As shown more clearly in Figure 6d, the gripper 504 is positioned over the space between the first and second pair of crimps. The angling of the gripper 504 relative to the bridge allows for the SMA wire 505 to be picked up. As described in more detail below in relation to the notch D position, the wire may be fed in a clock-wise direction into the first pair of crimps 350b, 352b by rotation of the rotating arm.

Figures 6e and 6f show an indexing position when the pin 503 is in notch C in the guide plate 502. Notch C is adjacent to notch B and is higher on the guide plate relative to notches A or B and thus the arm 600 is raised, i.e. moved in a vertical direction, when moving into notch C. The raised arm 600 means that it is easier to move the strip along the bridge, using the indexing positions as described in Figure 3c. In this position, the axis of the gripper 504 is aligned with the channel 532 and the bridge 530 but the gripper 504 is in a raised position relative to the channel 532 and the bridge 530.

As shown more clearly in Figure 6f, in this configuration, the gripper 504 comprises a pair of jaws including a fixed jaw 602 and a sliding jaw 604 which may be arranged to open and close by operation of a lever as described below. The pair of jaws are moveable between a first open position as illustrated in Figure 6b in which a wire may be placed between the jaws and a second closed, or gripping, position as shown in Figure 6f in which the wire is held securely by the jaws. The gripper 504 may comprise a cutting tool 606 for cutting the SMA actuator wire after it has been coupled to the actuating module. Lever 608 may be operated to release and position a wire between the jaws by moving the sliding jaw 604. The cutting tool may be a blade or knife and may be adjusted by lever 610 to cut the wire.

As described in relation to Figures 6a to 6f, the guide plate 502 enables movement of the alignment module 106 (and in particular, gripper 504) in two dimensions, i.e. in the horizontal direction (i.e. across the strip), and in a vertical direction (i.e. up and downwards relative to the strip). This may be useful for ensuring the SMA wire is in the fold/crease of each crimp, where the best coupling occurs when the crimps are closed.

As described above, when the apparatus is set in the first 'pick-up' position with the pin in notch B, there is an angle between the gripper and the bridge. Figures 7a and 7b show the components of the rotating frame 700 which allows this angle to be set. The rotating frame 700 comprises a support 702 which supports the guide plate 502 and the arm (not shown). The support 702 comprises a flange 706 which supports a pair of guide dowels 704. The wire (not shown) is routed between the guide dowels 704 whereby the guide dowels may control the angle of the wire when the wire is held by the gripper.

The support 702 is mounted on one end of a rotating arm 708. At an opposed end of the rotating arm 708, there is a lever 712 which is operated by a handle 714. The rotating arm 708 is elongate whereby the lever 712 and the support 702 are positioned either side of the bridge. The rotating arm 708 is mounted via a bearing to a base plate 710 which is mounted to a base of the apparatus. The location of the rotating arm 708 on the base plate 710 is slightly eccentric in light of the asymmetry of the crimps within each frame on the strip. Rotation of the rotating arm 708 allows adjustment left and right relative to the rest of the apparatus.

As shown more clearly in Figure 7b, in this arrangement, the handle 714 controls an integrated latch mechanism within the lever 712. The latch mechanism comprises a sprung bolt 716 which is raised when the handle 714 is activated to allow the rotating frame to be rotated. In Figure 7b, the rotating frame is set in its normal, unrotated position and the bolt 716 engages with a central locating slot whereby the rotating frame is locked in this position.

When the bolt 716 is raised, the rotating frame may be rotated clockwise to a clockwise position which may be termed a first rotated position. The handle 714 may then be released and the bolt 716 drops to engage with a first slot 718 in a base 722 of the apparatus. This clockwise position allows positioning of the wire in the first crimps as shown in Figures 6c and 6d. Alternatively, when the bolt 716 is raised, the rotating frame may be rotated anti-clockwise to an anticlockwise position which may be termed a second rotated position. The handle 714 may then be released and the bolt 716 drops to engage with a second slot 720. This anti-clockwise position allows positioning of the wire in another crimp as described below.

As shown both the slots 718 and 720 are elongate and angled to allow for the bolt 716 to slide within the slots 718. The sliding movement may allow the wire pull in angle to be adjusted. Furthermore, the sliding movement may allow the position of the guide dowels 704 relative to the crimp to be adjusted. As explained above, there is asymmetry of the crimps within each frame of the strip. When positioning the wire optimally within the crimp, the wire may be pulled to the back of the open crimp such that there is a slight angle in the wire at the edge of the crimp. It is desirable to keep the angle approximately the same at both sides of the crimp for optimal build reliability. However, the position of the dowels 704 on the support 702 is fixed and the dowels 704 may not be at the same distance from each crimp in each position. The sliding adjustment of the rotating frame may allow the gripper and dowels to position the wire into the optimal positions for the crimps despite the difference in distance.

As shown in Figure 7c, when the rotating arm 708 is rotated using the lever 712, both the arm 600 which holds the gripper and the die set comprising the die tool top 514 and the die tool base 516 are rotated. Figure 7d shows that the rotation of the die set is controlled by a fixed base piece 730 which is attached to the base of the apparatus. The fixed base piece 730 comprises a pair of end stops 732, 734 against which a protrusion 736 on the die tool base 516 abuts when the extent of clock-wise or anti-clockwise rotation is reached. Springs allow the rotating arm 708 to continue to rotate after the end stops are reached. The springs apply a stabilising load to keep the die set in position and provide a return force on the rotating arm 708 to pull the bolt against the locking slot as shown in Figure 7b.

Figures 8a to 8f illustrate the different configurations for the alignment module when the pin 503 is in the final notch D in the guide plate 502. Notch D is adjacent to notch C and is at a similar height to notches A and B but it will be appreciated that this is just one arrangement and the heights need not be the same. In the position shown in Figures 8a and 8b, when the pin 503 is in notch D, the arm 600 has been moved laterally across the strip 300 relative to the start position with the pin in notch C shown in Figure 6e and the arm is thus positioned on the other side of the channel 532 in the bridge 530.

As shown more clearly in Figure 8b, the wire 505 is held between the fixed jaw 602 and the sliding jaw 604 with the cutter 606 positioned away from the wire 505. Although the notches A to D are in sequence, it will be appreciated that the arm 600 need not be moved from notch A to notch B and so on. For example, the position shown in Figures 8a and 8b may be selected after the wire has been picked up in the start position shown in Figures 6c and 6d. The strip may be advanced using the indexing method described above. Once the correct component is in place, the pin 503 may be slid from notch C to notch D with the SMA wire held between the jaws to advance the wire over the actuator components, e.g. to advance the wire across the strip. As shown in Figure 8c, once the pin 503 is in notch D, the rotating frame shown in Figures 7a and 7b may be rotated to place the gripper 504 at an angle (i.e. no longer parallel) to the bridge 530 and the strip 300. The rotation may be achieved by activating the handle 714 on lever 712 to release the internal bolt so that the rotating frame can be rotated clockwise and the bolt can engage with the first slot 718 in the base 722 of the apparatus.

As the rotating frame is rotated clockwise, the wire 505 may be fed into a crimp as shown in more detail in Figure 8d in which the gripper has been removed for clarity. A lifting feature 850 of the bridge 530 comprises an elongate arc 800 in which the tips of the gripper jaws may rotate clockwise to bring the wire 505 into the first pair of crimps 350b, 352b which are joined by tab 310d. Thus, the first pair of crimps 350b, 352b may be termed clockwise crimps.

As an alternative to the clockwise rotation shown in Figure 8c, once the pin 503 is in notch D, the rotating frame shown in Figures 7a and 7b may be rotated anti-clockwise as shown in Figure 8e to bring the wire 505 into the second pair of crimps 350a, 352a. The rotation may be achieved by activating the handle on lever 712 to release the internal bolt so that the rotating frame can be rotated anti-clockwise and the bolt can engage with the second slot 720 in the base 722 of the apparatus.

As the rotating frame is rotated anti-clockwise, the wire 505 may be fed into a crimp as shown in more detail in Figure 8f in which the gripper has been removed for clarity.

It is also noted that as shown in Figures 8d and 8f, there is a second arcuate slot 802 in the lifting feature 850 which will allow the gripper jaws to rotate clock-wise or anti-clockwise to pick-up the wire 505.

In summary, the apparatus may be set in a starting position with the pin in notch B and the wire is picked up. The pin is moved to notch C so that the strip is moved to the correct component with the wire still held while the pin is in this notch. Once the correct component is in location, the pin is moved to notch D and the rotating arm may be rotated clockwise to feed the held wire into a first pair of crimps and anti-clockwise to feed the wire into a second pair of crimps. After the wire is fed into a pair of crimps, the crimps are closed and the wire is released by the gripper. The pin is then moved to notch B to pick up the wire before cutting the wire. The process can then begin again by cycling from B to C and to D. The pin is only placed in notch A for storage.

Figure 8g shows the detail of the lifting feature 850 of the alignment module 106. The lifting feature 850 may be plate-like or generally planar and comprise a first sloped edge 852 whereby as the strip moves over the sloped edge 852, the strip, in particular at least one of the crimps, is lifted to a raised position. The plate-like feature 850 also comprises a pair of elongate arcuate slots 800, 802 as shown in Figure 8f.

The plate-like feature 850 may be sprung loaded to bias the plate-like feature 850 in a first raised position. When in this position, the crimps on the strip may be lifted clear of the anvils as the strip is slid into the apparatus. The plate-like feature 850 may be pushed down to a second lower position by pins on the punch block as described below. The plate-like feature may thus be termed a trapdoor. It will be appreciated that the plate-like feature 850 may be biased in the lower position and moved to the raised position.

Figure 9a shows a perspective view of the apparatus when the pin 503 is engaged in notch D and the rotating frame has been rotated clockwise as shown in Figure 8c. This position may be termed the slack-adding position and the die tool top 514 is closer to the die tool base 516 than in any of the positions shown in Figures 8a to 8f. The movement of the die tool top 514 may be triggered by movement of the appropriate lever as described above.

The die tool set may also comprise a slack addition module 108 and the detail is shown in Figure 9b. The slack addition module 108 may allow the amount of wire between the pair of crimps 350, 352 to be adjusted. The slack addition module 108 may comprise a moveable slack adding member having a protrusion 900 which is received in a corresponding generally U-shaped recess 902. As the protrusion 900 presses the wire 505 down into the recess 902, the amount of wire between the pair of crimps is increased. The distance that the wire is forced into the recess 902 and hence the amount of wire between the crimps is controlled by a pin 950 which abuts an adjustable end stop 954 as explained below.

Figure 9b also shows details of a crimping module which is part of the apparatus. The crimping module may comprise a pair of punches 912 and a pair of anvils 914. The pair of punches 912 may be supported on a punch block which is provided on the die tool top 514. Similarly, the pair of anvils 914 may be supported on an anvil block which is on the die tool base 516. A crimp from each pair of crimps (not shown) rests on a corresponding anvil 914. Each anvil 914 is generally planar with a domed flange 916 either side of the recess 902. The sloped surfaces of the domed flanged 916 provide a smooth surface for the wire to slide against as the wire is pushed into the recess by the projection.

Figure 9c shows internal details to illustrate how the movement of the moveable slack adding member 936 is controlled. The moveable slack adding member 936 is mounted on a punch 944 which is moved downwards towards the bridge by spring 938. The extent of movement of the punch is controlled by a pair of pins 940 in corresponding linear slots 942. The moveable slack adding member 936 also slides relative to the punch 940 using another spring (not shown) and the extent of movement is also controlled by a pair of pins in linear slots. Either side of the moveable slack adding member 936, there are first and second pins 930, 932 which move in a vertical direction with the moveable slack adding member 936. Each pin 930, 932 extends through the block which supports the punch block which is shown in phantom. As shown in Figure 9b, an end of each pin 930, 932 engages with an upper surface of the strip 300 as the protrusion 900 from the moveable slack adding member 936 engages the wire and hence before either punch 912 reaches the corresponding crimp. These pins 930, 932 hold the strip 300 flat so that the crimps are level on the anvils before the crimping module is applied. The spring 934 on top of each pin 930, 932 compresses to allow the punch block to continue downwards. The pins 930, 932 may be cylindrical or may have features to apply pressure to certain areas of the strip to hold it flat. Figure 9d is a cutaway perspective view of the slack adding module to show how the amount of slack which is added may be adjusted. The pin 950 abuts an end stop 954 in the form of an elongate rod which passes up through the anvil block (not shown). A lower end of the end stop 954 rests on a bell crank 960 which is connected to a spindle 962. A concentric spring 964 around the end stop 954 pushes the end stop 954 downwards. The position of the bell crank 960 and hence the height that the end stop 950 protrudes is controlled by a micrometer that extends from the spindle 962.

It will be understood that some or all of the processes described above may be performed manually, e.g. by a human operator of apparatus 100, or may be performed automatically, e.g. by a robotic arm or other mechanised and automated process. It will be understood that parts of the die tool set may be moveable in a way to permit access to a human user or robotic arm. Accordingly, the present techniques also provide methods for assembling an actuating module comprising at least one SMA actuator wire.

Figure 10 shows a flow chart of example steps for assembling an actuating module comprising at least one SMA actuator wire. If the SMA actuator wire to be coupled to the actuating module comprises a core of SMA material surrounded by an electrically insulating coating, portions of the coating may need to be removed to improve the mechanical and electrical connection between the SMA actuator wire and actuating module, as explained above. Thus, in embodiments, the process may begin with selectively removing the electrically insulating coating at a first portion on a first length of the SMA actuator wire and at a second portion on the first length of the SMA actuator wire (step S800). If the SMA actuator wire was selectively coated with electrically insulating coating, or is obtained in a prepared form, then this step may be omitted and thus the removal step may be optional.

The process may comprise picking up a first end of the first length of SMA wire (S801) and then guiding the first length of the SMA actuator wire into a first pair of crimps (step S802) with the first and second portions of the wire being received into respective crimps. Optionally, slack may be added to the first length of SMA actuator wire once it is provided between the crimps (step S803), for the reasons described above.

The first pair of crimps are then simultaneously closed (step S804), using a pair of punches and anvils, for example. Once the crimps are closed, a cutting tool may be used to cut the end of the SMA actuator wire which is coupled to a spool 402 or source of the wire. This may involve the steps of releasing the first end of the first length of SMA wire (step S805), then picking up a first end of the next (second) length of SMA wire, and then cutting the second end of the crimped first length of SMA wire (step S806).

The next second length of SMA wire (with the insulating coating at its first and second portions removed as necessary) may then be guided into the second pair of crimps, e.g. by rotating in the opposite direction to the direction used when guiding the first length of SMA wire into the first pair of crimps. The slack adding, crimping and cutting steps may then be repeated to prepare a component, e.g. a fret having four crimps with two crossing wires. The process is repeated until all components have been completed with the indexing movement of the strip as described above.

In a related approach of the present techniques, there is provided a non- transitory data carrier carrying processor control code to implement any of the processes or methods described herein. In other words, the processor control code when controlling the modules may cause the modules to implement any of the processes or methods described herein.

As will be appreciated by one skilled in the art, the present techniques may be embodied as a system, method or computer program product. Accordingly, present techniques may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects.

Furthermore, the present techniques may take the form of a computer program product embodied in a computer readable medium having computer readable program code embodied thereon. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may be, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

Computer program code for carrying out operations of the present techniques may be written in any combination of one or more programming languages, including object oriented programming languages and conventional procedural programming languages. Code components may be embodied as procedures, methods or the like, and may comprise sub-components which may take the form of instructions or sequences of instructions at any of the levels of abstraction, from the direct machine instructions of a native instruction set to high-level compiled or interpreted language constructs.

Embodiments of the present techniques also provide a non-transitory data carrier carrying code which, when implemented on a processor, causes the processor to carry out any of the methods described herein.

The techniques further provide processor control code to implement the above-described methods, for example on a general purpose computer system or on a digital signal processor (DSP). The techniques also provide a carrier carrying processor control code to, when running, implement any of the above methods, in particular on a non-transitory data carrier. The code may be provided on a carrier such as a disk, a microprocessor, CD- or DVD-ROM, programmed memory such as non-volatile memory (e.g. Flash) or read-only memory (firmware), or on a data carrier such as an optical or electrical signal carrier. Code (and/or data) to implement embodiments of the techniques described herein may comprise source, object or executable code in a conventional programming language (interpreted or compiled) such as C, or assembly code, code for setting up or controlling an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array), or code for a hardware description language such as Verilog (RTM) or VHDL (Very high speed integrated circuit Hardware Description Language). As the skilled person will appreciate, such code and/or data may be distributed between a plurality of coupled components in communication with one another. The techniques may comprise a controller which includes a microprocessor, working memory and program memory coupled to one or more of the components of the system.

It will also be clear to one of skill in the art that all or part of a logical method according to embodiments of the present techniques may suitably be embodied in a logic apparatus comprising logic elements to perform the steps of the above-described methods, and that such logic elements may comprise components such as logic gates in, for example a programmable logic array or application-specific integrated circuit. Such a logic arrangement may further be embodied in enabling elements for temporarily or permanently establishing logic structures in such an array or circuit using, for example, a virtual hardware descriptor language, which may be stored and transmitted using fixed or transmittable carrier media.

In an embodiment, the present techniques may be realised in the form of a data carrier having functional data thereon, said functional data comprising functional computer data structures to, when loaded into a computer system or network and operated upon thereby, enable said computer system to perform all the steps of the above-described method.

Those skilled in the art will appreciate that while the foregoing has described what is considered to be the best mode and where appropriate other modes of performing present techniques, the present techniques should not be limited to the specific configurations and methods disclosed in this description of the preferred embodiment. Those skilled in the art will recognise that present techniques have a broad range of applications, and that the embodiments may take a wide range of modifications without departing from any inventive concept as defined in the appended claims.