TECHNICAL FIELD

The disclosure relates to a locking arrangement suitable for a housing of an electronic device, and a housing for an electronic device, as well as a method of operating a locking arrangement in a housing of an electronic device.

BACKGROUND

In smart electronic devices with a display and a housing for electronic components, the display module and a back cover are typically attached together or to a main body using glue or adhesive solutions. This makes dismantling and repairing of the smart devices difficult and expensive in repair centers or service shops. In particular, for such dismantling the back cover is heated with hot air until the adhesive force of the glue or adhesive starts to weaken, and the back cover can be removed using special tools for example suction cups. Parts are easily broken during such dismantling process and need to be replaced with new ones, and new adhesive or glue need to applied when re-assembling the back cover.

Another problem is that in many electronic devices it is currently not even possible for the end user to remove the back cover without breaking the warranty rules. However, consumer law changes in certain jurisdictions (such as EU Eco design requirements) will soon require that certain electronic components, such as batteries must be easily reachable and repairable by the end-user without the use of specially designed repair equipment.

One solution would be using visible manual locking features or screws to open the back cover, however this also requires specialized tools and results in a less appealing device, while also reducing the usable surface on the back cover and/or the main body.

There is therefore a need for a solution that allows easy access to the inside of a housing of an electronic device, thereby enabling a repair person to dismantle the electronic device, and also enabling the end-user to remove the back cover and easily access and replace the battery or any additional component, such as a SIM or memory card, located under the back cover. There is a parallel need to have more uniform industrial design of such an electronic device without screw heads or card doors on its visible surface.

SUMMARY

It is an object to provide an improved locking arrangement suitable for a housing of an electronic device that overcomes the above problems. To achieve this, it is proposed that a common single-piece actuator is used comprising a Smart Material Alloy wire or Smart Material Alloy sheet to actuate a locking arrangement and enable a cover of an electronic device to be at least partially removed from a base, triggered by an input from a touchscreen or from a separate electrical switch of the device.

The foregoing and other objects are achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description, and the figures.

According to a first aspect, there is provided a locking arrangement for a housing comprising a base and a removable cover. The locking arrangement comprises at least one locking element arranged in the cover, and at least one movable element arranged in the base. The movable element is movable between a locked position and an open position, wherein in the locked position the movable element engages the locking element holding the cover connected to the base, and in the open position the movable element disengages from the locking element and enables the cover to be at least partially removed from the base. A single-piece actuator is mechanically interconnected with the movable element and is configured to deform in response to electric activation at least to an extent to move the movable element from the locked position to the open position.

This solution provides a locking arrangement for a removable cover of an electronic device that is simple to operate and comprises few components, making it cost efficient to produce, structurally lightweight, as well as reliable and effective in use. The single -piece actuator used in the locking arrangement enables reasonable accuracy, sufficiently long stroke and strength for moving connected movable elements.

The size of the locking arrangement can be minimized due to the actuation being implemented electrically instead of mechanically.

Using an actuator that is configured to deform in response to electric activation also allows for avoiding interference with other VCM actuators such as OIS and AF systems in the device.

With the locking arrangement not requiring screws or other attachment means on the outer surface of the device, uniform and aesthetically pleasing industrial design can be provided.

In a possible implementation form of the first aspect, the locking arrangement comprises an anchor element arranged in the base; and the single-piece actuator comprises a fixed portion connected to the anchor element and configured to remain stationary during electric activation, and a moving portion connected to a movable element, thus enabling the movable element to be displaced during electric activation with respect to the fixed portion.

In an embodiment the anchor element comprises electrical terminals for connecting to a supply of current. In an embodiment the anchor element is a printed wiring board, such as a Flexible Printed Circuit, FPC, board.

In an embodiment the at least one fixed portion is configured to be fastened to the anchor element by means of at least one electrically conductive fastening element. In an embodiment the at least one electrically conductive fastening element comprise at least one of rivets, conductive glue, or spring-based members.

In an embodiment the electric activation comprises applying current to the single -piece actuator from a battery arranged in the base, via the anchor element and the at least one electrically conductive fastening element.

In a further possible implementation form of the first aspect, the locking arrangement comprises two movable elements arranged on opposite sides of the base, and an anchor element arranged in the base between the two movable elements. The single -piece actuator comprises a fixed portion connected to the anchor element and configured to remain stationary during electric activation, and two moving portions each being connected to a respective movable element, the two moving portions being configured to be displaced during electric activation with respect to the fixed portion in opposite directions. This arrangement allows displacement of two movable elements by means of only one actuator, thereby reducing the number of components needed and hence freeing up space for other unrelated components and/or allowing the size of the device comprising the actuator to be reduced.

In a further possible implementation form of the first aspect, the single-piece actuator further comprises at least one actuating arm with a length arranged between a fixed portion and a moving portion, and the at least one actuating arm is configured to contract along its length in response to an increase in temperature caused by electric activation and to thereby displace a moving portion with respect to a fixed portion.

In a further possible implementation form of the first aspect, at least one actuating arm is arranged in a zig-zag shape between a fixed portion and a moving portion for providing additional contracting length for the displacement of the moving portion.

In a further possible implementation form of the first aspect, the single -piece actuator comprises an SMA, shape-memory alloy, component, the SMA component being configured to deform according to a temperature-induced phase transformation profile.

In an embodiment only the actuating arm comprises an SMA component, the at least one fixed portion and/or the at least one moving portion being configured not to deform in response to electric activation.

In a further possible implementation form of the first aspect, the single -piece actuator comprises an SMA sheet extending between a fixed anchor element arranged in the base and a movable element. In another possible implementation form of the first aspect, the single-piece actuator comprises an SMA wire extending between a fixed anchor element arranged in the base and at least one movable element.

In a further possible implementation form of the first aspect, at least one movable element is a rotating element arranged to rotate around a rotational axis. The SMA wire comprises a curved portion arranged to engage the rotating element at an attachment portion, the curved portion being shaped to tangentially displace the attachment portion with respect to the rotational axis during electric activation of the SMA wire.

In an embodiment the SMA wire comprises two curved portions arranged at each rotating element, and a straight portion arranged between the two curved portions, the straight portion being arranged in a hinged manner in an elongated hole in the rotating element parallel with the rotational axis

In a further possible implementation form of the first aspect, the SMA wire is mechanically interconnected with the at least one movable element in a hinged manner, allowing rotational movement of the movable element with respect to a connecting portion of the SMA wire.

In a further possible implementation form of the first aspect, at least one movable element is resiliently biased towards the locked position by a resilient element arranged to urge the at least one movable element towards a corresponding locking element and counter the displacement of the single -piece actuator when the single-piece actuator is not electrically activated.

In an embodiment the resilient element is one of a torsion spring, a helical spring or a spring clip.

In an embodiment the resilient element is arranged on a same side of the movable element as the single -piece actuator.

In a further possible implementation form of the first aspect, at least one movable element is a rotating element arranged to rotate around a rotational axis at least between a first angle wherein the rotating element engages a corresponding locking element in the locked position, and a second angle wherein the rotating element disengages from a corresponding locking element in the open position.

In a further possible implementation form of the first aspect, at least one movable element is a sliding element arranged to slide along a translational axis at least between a locked position wherein the sliding element engages a corresponding locking element and an open position wherein the rotating element disengages from a corresponding locking element.

In a further possible implementation form of the first aspect, at least one movable element comprises a recess shaped to receive at least a portion of a locking element in the locked position, thus enabling secure engagement in a locked position.

In a further possible implementation form of the first aspect, the cover comprises a rim extending along a circumference. The at least one locking element comprises at least one protrusion extending from the rim towards an inside of the cover, a surface of the protrusion being shaped for engaging with a corresponding surface of a movable element in the locked position, thus providing a secure engagement.

In a further possible implementation form of the first aspect, the cover comprises at least one rib extending from the rim towards an inside of the cover, the rib being shaped for engaging with corresponding grooves arranged in the base, thus providing a secure engagement.

According to a second aspect, there is provided a housing for an electronic device, the housing comprising a base; a removable cover; and at least one locking arrangement according to any one of the possible implementation forms of the first aspect for alternately keeping the cover attached to the base or enabling the cover to be at least partially removed from the base.

In an embodiment the base comprises a display unit arranged on an outer side, and wherein the housing further comprises electronic device components arranged in the base, the electronic device components being at least partially exposed when the cover is removed from the base.

In an embodiment the electrical current is applied to at least one single-piece actuator upon receiving user input via a virtual button displayed on a display unit of the electronic device or via a button arranged on the housing of the electronic device.

In a possible implementation form of the second aspect, the housing comprises two locking arrangements according to any one of the possible implementation forms of the first aspect, the two locking arrangements being arranged in opposite sides of the housing for providing a more secure engagement of the cover in the locked position.

According to a third aspect, there is provided a method of operating a locking arrangement according to any one of the possible implementation forms of the first aspect for enabling a cover of an electronic device to be at least partially removed from a base, the method comprising applying an electrical current to at least one single -piece actuator to induce resistive heating such that a deformation is generated whereby at least a portion of the single -piece actuator contracts along its length, the deformation moving a respective movable element mechanically interconnected with the single-piece actuator from the locked position to the open position.

In addition to the advantages of the locking arrangement stated above, this method of operating the locking arrangement uses a minimum number of components, making it cost efficient and reliable in use. The deformation-based actuation provides easy shape formability, thin form factor, high force and long movement generation for actuator applications, as well as silent operation, and no interference with other VCM actuators such as OIS and AF systems nearby with electromagnetic fields.

In an embodiment the electrical current is applied to at least one single-piece actuator upon receiving user input via a virtual button displayed on a display unit of the electronic device or via a button arranged on the housing of the electronic device, thus enabling simple operation of the locking arrangement by an end user without the need of any special tools. In a possible implementation form of the third aspect, the method further comprises the step of deactivating the at least one single-piece actuator, the deactivation enabling a return of the at least one single-piece actuator to a non-deformed shape, the return moving the respective mechanically interconnected movable element from the open position to the locked position.

In an embodiment the single-piece actuator is configured to return to an at least partly nondeformed shape in response to a change in the electric activation at least to an extent to move the respective mechanically interconnected movable element from the open position to the locked position.

In a further possible implementation form of the third aspect, at least one movable element is resiliently biased towards the locked position, and deactivating the at least one singlepiece actuator comprises removing the electrical current so as to enable any resiliently biased movable element to return to the locked position.

These and other aspects will be apparent from the embodiments described below.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present disclosure, the aspects, embodiments and implementations will be explained in more detail with reference to the example embodiments shown in the drawings, in which:

Fig. 1 shows a partial cross-sectional view of one side of a locking arrangement in the locked position according to an example of the embodiments of the disclosure;

Fig. 2A shows a cross-sectional view of a locking arrangement in the locked position (Pl) according to an example of the embodiments of the disclosure; Fig. 2B shows a cross-sectional view of a locking arrangement in the open position (P2) according to an example of the embodiments of the disclosure;

Fig. 3 shows an isometric view of a locking arrangement comprising an SMA wire, according to an example of the embodiments of the disclosure;

Fig. 4A and 4B show a top and bottom view of a locking arrangement comprising an SMA sheet in the locked position, according to an example of the embodiments of the disclosure;

Fig. 5A and 5B show a top and bottom view of a locking arrangement comprising an SMA sheet in the open position, according to an example of the embodiments of the disclosure;

Fig. 6A and 6B show cross-sectional views of a locking arrangement comprising an SMA sheet in the locked and open position, according to an example of the embodiments of the disclosure;

Fig. 7 shows a partial isometric view of a locking arrangement comprising an SMA wire, according to an example of the embodiments of the disclosure;

Fig. 8 shows a partial cross-sectional view of a rib of a locking arrangement, according to an example of the embodiments of the disclosure;

Fig. 9 shows a top view of a housing for an electronic device, according to an example of the embodiments of the disclosure;

Fig. 10 shows an exploded isometric view of a housing for an electronic device comprising a removable battery, according to an example of the embodiments of the disclosure;

Fig. 11 shows an isometric view of a removable cover of a housing for an electronic device, according to an example of the embodiments of the disclosure; and Fig. 12 shows an isometric view of a base of a housing for an electronic device, according to another example of the embodiments of the disclosure.

DETAILED DESCRIPTION

Figs. 1-3 and 7 show one example of a locking arrangement, while Figs. 4-6 show another example of a locking arrangement according to the present disclosure. Figs. 8-12 show common details for both examples of the locking arrangement.

In particular, Figs. 1-3 and 7 show an example of a locking arrangement 4 with a singlepiece actuator 7 that comprises an SMA wire 12 extending between a fixed anchor element 8 arranged in the base 2 and one or more movable elements 6, while Figs. 4-6 show another example of a locking arrangement 4 wherein the single-piece actuator 7 comprises an SMA sheet 11 extending between a fixed anchor element 8 arranged in the base 2 and one or more movable elements 6. Working principal of the SMA sheet 11 is the same as the SMA wire 12 as will be explained below.

In either example, the method of operating a locking arrangement 4 is the same, and comprises the steps of applying an electrical current to at least one single-piece actuator 7 to induce resistive heating such that a deformation is generated whereby at least a portion of the single -piece actuator 7 contracts along its length, the deformation moving a respective movable element 6 mechanically interconnected with the single-piece actuator 7 from the locked position Pl to the open position P2.

A subsequent deactivation enables a return of the single-piece actuator 7 to a non-deformed shape, the return moving the respective mechanically interconnected movable element 6 from the open position P2 to the locked position Pl.

As will be explained below, each movable element 6 may be resiliently biased towards the locked position Pl, whereby deactivating the single-piece actuator 7 (removing the electrical current) enables the resiliently biased movable element 6 to return to the locked position Pl. Fig. 1 shows a locking arrangement 4 according to the first example, arranged in a housing 1 for an electronic device. The house comprises a base 2 and a removable cover 3, with a display unit 26 arranged on the base 2 facing an outer side of the housing 1.

The locking arrangement 4 comprises at least one locking element 5 arranged in the cover 3; and at least one movable element 6 arranged in the base 2 to be movable between a locked position Pl and an open position P2 (shown in detail in Figs. 2A and 2B).

A single -piece actuator 7 is arranged to be mechanically interconnected with the at least one movable element 6; the single -piece actuator 7 being configured to deform in response to electric activation at least to an extent to move the at least one movable element 6 from the locked position Pl to the open position P2.

The single-piece actuator 7 may comprise a shape-memory alloy (SMA) component, the SMA component being configured to deform according to a temperature-induced phase transformation profile. The SMA component may be made of a Nickel-Titanium alloy, (NiTinol).

In the example of Figs. 1-3 and 7 the single -piece actuator 7 comprises an SMA wire 12 extending between a fixed anchor element 8 arranged in the base 2 and one or more movable elements 6. In an example, the SMA wire may be of a diameter of 0.25 mm. In the example of Figs. 4-6 the single-piece actuator 7 comprises an SMA sheet 11.

In either case, the SMA component is heated to 90 degrees C for 1 second to achieve a martensite phase with a current of 1050 mA. This makes the SMA component contract 1- 3% of its length (3% for SMA wire and 1-3% for SMA sheet) and to pull the connected movable element 6 open with about 900 g force and by doing so releases the locking of the cover 3, so that a repair person or the end user can access the inside of the housing 1.

The SMA wire 12 or SMA sheet 11 will return to austenite phase and elongates to its initial length after cooling. This cooling time of the SMA wire 12 is about 4.5 seconds.

The above-mentioned parameters are for reference only. There are many different options of the SMA wires available, and parameters are depending on chosen material alloy and wire diameter. The movable elements 6 may be resiliency biased towards the locked position Pl by a resilient element 10 arranged at each movable element 6 to urge the movable elements 6 towards a corresponding locking element 5 and counter the displacement of the singlepiece actuator 7 when the single-piece actuator 7 is not electrically activated. The resilient element 10 may be a torsion spring, a helical spring or a spring clip.

The resilient element 10 may arranged on a same side of the movable element 6 as the single -piece actuator 7, or alternatively on an opposite side of the movable element 6.

Material alloy, shape and thickness of the SMA components, force of the resilient element 10 and the used electrical current are to be chosen according to needed opening force and travel of the movable element 6.

In the examples of Figs. 1-3 and 7, at least one movable element 6 is a rotating element 13 arranged to rotate around a rotational axis 14 (as explained below and shown in Fig. 3) at least between a first angle wherein the rotating element 13 engages a corresponding locking element 5 in the locked position Pl, and a second angle wherein the rotating element 13 disengages from a corresponding locking element 5 in the open position P2.

Figs. 2A and 2B, as well as Fig. 3 illustrate an example wherein the locking arrangement 4 comprises two movable elements 6 arranged on opposite sides of the base 2, and an anchor element 8 is arranged in the base 2 between the two movable elements 6. In this example the single-piece actuator 7 comprises a fixed portion 71 connected to the anchor element 8 and configured to remain stationary during electric activation, and two moving portions 72 each being connected to a respective movable element 6, the two moving portions 72 being configured to be displaced during electric activation with respect to the fixed portion 71 in opposite directions.

As shown in Fig. 2A, in the locked position Pl the at least one movable element 6 engages the at least one locking element 5 holding the cover 3 at least partially connected to the base 2. As shown in Fig. 2B, in the open position P2 the at least one movable element 6 disengages from the at least one locking element 5 and enables the cover 3 to be at least partially removed from the base 2. As mentioned above, the locking arrangement 4 comprises an anchor element 8 arranged in the base 2, and the single-piece actuator 7 comprises a fixed portion 71 connected to the anchor element 8 and configured to remain stationary during electric activation, and moving portions 72 connected to movable elements 6 that are configured to be displaced during electric activation with respect to the fixed portion 71. The single -piece actuator 7 further comprises actuating arms 73 with a length arranged between the fixed portion 71 and the moving portions 72, the actuating arms 73 being configured to contract along their length in response to an increase in temperature caused by electric activation and to thereby displace a moving portion 72 with respect to a fixed portion 71, as also shown in Fig. 3.

In an embodiment only the actuating arms 73 comprise an SMA component, the at least one fixed portion 71 and/or the at least one moving portion 72 being configured not to deform in response to electric activation.

Fig. 3 shows the locking arrangement 4 alone, isolated from the rest of the housing 1, to illustrate the working of the locking arrangement 4 under electric activation. The anchor element 8 may comprise electrical terminals for connecting to a supply of current, and the fixed portion 71 of the single-piece actuator 7 may be fastened to the anchor element 8 by means of at least one electrically conductive fastening element 9.

The anchor element 8 may be a printed wiring board, such as a Flexible Printed Circuit (FPC) board. The electrically conductive fastening elements 9 may comprise at least one of rivets, conductive glue, or spring-based members.

The electric activation may be executed by applying current to the single -piece actuator 7 from a battery 25 arranged in the base 2 (as shown in Figs. 6A and 6B, and on Fig. 10), via the anchor element 8 and the electrically conductive fastening elements 9.

As also illustrated in Fig. 3, both movable elements 6 are rotating elements 13 arranged to rotate around a rotational axis 14, wherein during electric activation the contraction of the SMA wire 12 pulls and rotates the rotating elements 13 with respect to the rotational axis 14. The SMA wire 12 may be mechanically interconnected with the at least one movable element 6 in a hinged manner, allowing rotational movement of the movable element 6 with respect to a connecting portion of the SMA wire 12.

Fig. 7 illustrates in detail how the SMA wire 12 may comprise curved portions 15 on both ends arranged to engage the rotating elements 13 at attachment portions 17, the curved portions 15 being shaped to tangentially displace the attachment portions 17 with respect to the rotational axis 14 during electric activation of the SMA wire 12. In the particular illustrated example the SMA wire 12 comprises two curved portions 15 arranged at each rotating element 13 respectively, and a straight portion 16 arranged between the two curved portions 15, the straight portion 16 being arranged in a hinged manner in an elongated hole 18 in the rotating element 13 parallel with the rotational axis 14.

As also shown in Fig. 7, each movable element 6 may comprise a recess 61 shaped to receive at least a portion of a locking element 5 in the locked position Pl.

Figs. 4A and 4B, Figs. 5A and 5B, and Figs. 6A and 6B illustrate the locking arrangement 4 of another example wherein the single -piece actuator 7 comprises an SMA sheet 11 extending between a fixed anchor element 8 arranged in the base 2 and a movable element 6. In these examples, the one or more movable element 6 is a sliding element 19 arranged to slide along a translational axis 20 at least between a locked position Pl wherein the sliding element 19 engages a corresponding locking element 5 and an open position P2 (as shown in Figs. 6A and 6B) wherein the sliding element 19 disengages from a corresponding locking element 5. In these examples the resilient element 10 is a spring clip arranged on a same side of the sliding element 19 as the SMA sheet 11.

As also shown in Figs. 4A-4B, and Figs. 5A-5B, the SMA sheet 11 is arranged in a zig-zag shape between the anchor element 8 and the sliding element 19 for providing additional contracting length for the displacement of the sliding element 19.

In particular, Fig. 4A and 4B illustrate (from a top and bottom view) the locking arrangement 4 with the SMA sheet 11 in a locked (extended) position, the resilient element 10 (spring clip) pushing the sliding element 19 out into engagement with the locking element 5 (not shown). Figs. 5A and 5B illustrate (also from a top and bottom view) the same locking arrangement 4 now activated through the electrically conductive fastening element 9, with the SMA sheet 11 in an open (contracted) position, pulling the sliding element 19 away from engagement with the locking element 5 (not shown), and thus opening the locking arrangement 4 and letting the cover 3 be removed from the base 2.

Figs. 6A and 6B illustrate the same locking arrangement 4, wherein Fig 6A corresponds to the locked position (Pl) shown in Figs. 4A and 4B, and Fig 6B corresponds to the open position (P2) shown in Figs. 5A and 5B, wherein features and reference numbers apply in a similar manner as explained before.

As shown in Figs. 6 A and 6B, the cover 3 comprises a rim 21 extending along a circumference; and the at locking elements 5 comprise protrusions 22 extending from the rim 21 towards the inside of the cover 3. The surface of the protrusion 22 is shaped for engaging with a corresponding surface of a movable element 6 in the locked position Pl - the same solution may be applied to the example with the rotating element 13 and the sliding element 19, as they can both engage with the same protrusion 22.

Fig. 8 illustrates an additional measure that can be taken to further secure the engagement between the base 2 and the removable cover 3 in the locked position, wherein the cover 3 further comprises at least one rib 23 extending from the above-mentioned rim 21 towards an inside of the cover 3, these ribs 23 (preferably several ribs 23 as shown in Fig. 11) being shaped for engaging with corresponding grooves 24 arranged in the base 2.

Figs. 9 and 10 illustrate a housing 1 for an electronic device according to the present disclosure, shown in an assembled and disassembled state. The housing 1 comprises, as explained above: a base 2, a removable cover 3; and at least one locking arrangement 4 according to one of the above illustrated examples, for alternately keeping the cover 3 attached to the base 2 or enabling the cover 3 to be at least partially removed from the base 2. The electrical current may be applied to at least one single-piece actuator 7 upon receiving user input via a virtual button 28 displayed on a display unit 26 of the electronic device or via a button 27 arranged on the housing 1 of the electronic device. As shown in Fig. 10, the base 2 comprises a display unit 26 arranged on an outer side, and the housing further comprises electronic device components, such as a battery 25, arranged in the base 2, the electronic device components being at least partially exposed when the cover 3 is removed from the base 2. As illustrated, the housing 1 may comprise two locking arrangements 4 arranged in opposite sides of the housing 1, and optionally further combined with several ribs 23 arranged in the cover 3 (as shown in Fig. 11) engaging with corresponding grooves 24 arranged in the base 2, to provide secure engagement between the removable cover 3 and the base 2 in the locked position.

Finally, Figs. 11 and 12 illustrate the cover 3 and the base 2 separated from each other after disengaging the locking arrangement 4. As shown in Fig. 11, the cover 3 may comprise two protrusions 22 on its sides extending from the rim 21 towards an inside of the cover 3 at an upper or lower region thereof, to engage with the movable elements 6 of the locking arrangement 4 shown in Fig. 12, as well as multiple ribs 23 shaped for engaging in a “hooking” manner with corresponding grooves 24 shown in Fig. 12 arranged in the base 2, thereby providing additional “fixed” engagement means that are easily disengaged once the locking arrangement 4 opens, allowing the cover 3 to be removed. The ribs 23 are typically located on an other end of the housing 1 opposite to the protrusions 22 for optimal locking.

The various aspects and implementations have been described in conjunction with various embodiments herein. However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed subject-matter, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

The reference signs used in the claims shall not be construed as limiting the scope. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion of the entire written description of this disclosure. As used in the description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down”, as well as adjectival and adverbial derivatives thereof (e.g., “horizontally”, “rightwardly”, “upwardly”, etc.), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms “inwardly” and “outwardly” generally refer to the orientation of a surface relative to its axis of elongation, or axis of rotation, as appropriate.