GB2533576A

GB2533576A - Actuator

Info

Publication number: GB2533576A
Application number: GB1422919.9A
Authority: GB
Inventors: Marchant Robert
Original assignee: Marchantcain Design Ltd
Current assignee: Marchantcain Design Ltd
Priority date: 2014-12-22
Filing date: 2014-12-22
Publication date: 2016-06-29
Anticipated expiration: 2034-12-22
Also published as: GB2533576B

Abstract

An actuator, particularly for an active spoiler (12, Figure 1a) on a road car, but also suitable for driving a wing mirror, a window regulator, a heating or air conditioning vent or adjustable seating, comprises a carriage 22 cooperable with, and guided by, a guide 16 defining a region 18 adapted to guide carriage 22 for displacement along a path. Guide 18 also has means, typically at a predetermined position along the path, to guide carriage 22 for pivotal movement; this may be a branch track 20. In embodiments, carriage 22 may have two followers 26, 28 or a single hexagonal follower (26, Figure 6). Carriage 22 is preferably driven by a cable drive; suitably, two cables 38, 46 are provided to drive the carriage in opposite directions which may be driven in synchronisation by a common motor 44.

Description

ACTUATOR

This invention relates to an actuator, and in particular to a cable operated actuator capable of driving a component for displacement along a path, and of driving the component for pivotal movement. The pivotal movement may occur only at a predetermined position along the path, or may occur simultaneously with the displacement to result in a compound movement.

There are a number of applications in which is it desired to be able to drive a component for movement along a path and, when in at least one position along the path, to be able to drive the component for pivotal movement. By way of example, where a road vehicle is fitted with an active spoiler system, the spoiler will typically be required to be moved or displaced between a stowed or retracted position and a raised, deployed position, this movement following a predetermined path. The predetermined path is typically a linear path, but this need not always be the case. When in a fully deployed position, it may be desirable for the spoiler to be capable of being pivoted in a controlled fashion so as to increase the drag coefficient of the vehicle and thereby serve as an air brake. It will be appreciated, however, this is just one application in which movement of this type may be desired, and that the actuator may be used in a number of other applications.

Where a component is driven along a path and, when in at least one position along the path, it is arranged to be driven for pivotal movement, typically two separate actuators are provided, one controlling the movement of the component along the path, and the other controlling the pivotal motion. Whilst such arrangements may operate adequately, as each actuator will typically have a motor such as an electrically powered motor associated therewith, the provision of two actuators, the associated motors and motor control arrangements results in the overall system being relatively complex, heavy and expensive.

It is an object of the invention to provide an actuator suitable for use in such applications and in which at least some of the disadvantages associated with known actuators are overcome or are of reduced effect.

According to the present invention there is provided an actuator comprising a guide, a carriage cooperable with the guide and guided for movement thereby, the guide defining a region adapted to guide the carriage for displacement along a path and to guide the carriage for pivotal movement.

In this technology the carriage is often referred to as a nipple chamber, although in this application the carriage comprises a nipple chamber specifically designed to achieve a desired motion.

In some arrangements the guide may be arranged to guide the carriage for displacement and, once the carriage occupies a predetermined position, to allow it to undertake pivotal movement. Alternatively, it may be designed to permit displacement and pivotal movement to occur simultaneously such that the movement undertaken by the carriage is a compound of the displacement and the pivotal movement.

The path is conveniently a linear path. The predetermined position at which the carriage is guided for pivotal movement is conveniently at an end of the path. However, it will be appreciated that this need not always be the case. By way of example, the path could be of curved form. In certain arrangements, it may be desirable for the guide to guide the carriage for pivotal movement at a plurality of discrete positions, for example at both ends of the path.

Conveniently, the carriage is arranged to be driven for movement relative to the guide by a cable drive arrangement, conveniently an electric motor driven cable drive arrangement. Preferably, the operation of the cable drive arrangement is such that operation thereof drives the carriage for movement along the path, continued operation thereof once the carriage has reached the predetermined position, for example at the end of the path, driving the carriage for pivotal movement.

The guide conveniently includes a guide formation cooperable with first and second follower members provided on the carriage to guide the carriage for movement. By way of example, the guide formation may comprise a guide slot. However, arrangements are also possible in which the guide formation comprises a guide channel. Furthermore, it may be possible to provide a guide formation in the form of a guide rail. The followers members may take a range of forms.

For example they may be of cylindrical form with a circular cross-section. Alternatively, they could have, for example, a polygonal cross-sectional shape.

The guide formation is preferably of bifurcated form, including a main section serving, in use, to guide the carriage for movement along the path, and a branched region serving, in use, to guide the carriage for pivotal movement. In the branched region, the guide formation conveniently includes a limb of part circular form, the centre of curvature of the limb being centred upon an end part of the main section.

It will be appreciated that with such an arrangement, when both of the follower members are located within the main section, the carriage is guided for movement along the path. Once the first follower member has reached the end of the main section, further movement of the carriage along the path is not permitted. Instead, the carriage can pivot about the location of the first follower member at the end of the main section, the second follower member being guided along the curved limb of the branched region.

By modification of the shape of the guide slot or formation, other net carriage movements may be achieved, for example the carriage may be guided to undertake a displacement and pivotal movement simultaneously. Separate guide formations for the follower members may be provided.

In an alternative arrangement the guide may comprise a guide formation with which a single follower member is cooperable, the follower member being of non-circular cross-section, and the guide formation comprising a slot or channel including a main part of uniform width, and an end part of enlarged width compared to that of the main part such that when the follower member is located at the predetermined position (within the enlarged end) angular movement of the follower member within the guide formation is permitted, such pivotal movement being resisted when the follower member is not located at the predetermined position.

By way of example, the follower member may be of polygonal, such as hexagonal, form, opposing sides thereof bearing against the guide formation when the follower member is not located at the predetermined position to resist angular movement of the follower member, the follower member being able to move angularly when located within the enlarged end.

A bush may be provided within the enlarged end, the bush defining a cavity shaped to receive the follower member.

As mentioned above, the carriage is conveniently driven for movement by a cable drive arrangement. Conveniently, the carriage has provided thereon a cable engagement device designed such that a point of contact between the cable and the cable engagement device is offset from the path followed by the follower member(s) when following the path. Such an arrangement is advantageous in that, when the predetermined position is reached, the force applied by the cable to the carriage will be applied in a direction offset from the location of the follower member about which the pivotal movement occurs. The cable engagement device may be cooperable with a pair of cables, one to drive the carriage in one direction, for example for use in deployment, and the other to drive the carriage in the reverse direction, for example for stowing movement. The cables are conveniently driven by a common motor.

One or more such actuators may be used in combination, depending upon the application in which invention is to be employed, to drive and guide one or more associated components for movement.

According to a second aspect of the invention there is provided a system comprising a member to be moved and at least one actuator of the type defined hereinbefore positioned and operable to drive the member for movement. By way of example, the member may comprise a spoiler of an active spoiler system moveable between a stowed position and a deployed position, and once in the deployed position, to drive the spoiler to an air brake position. According to another aspect of the invention there is provided a window regulator system comprising a glass panel and at least one actuator as described hereinbefore positioned and operable to drive the glass panel for movement. As set out hereinbefore, the movement of the glass panel may be relatively complex, comprising a displacement and a pivoting movement, either undertaken consecutively or simultaneously.

The invention will further be described, by way of example, with reference to the accompanying drawings, in which: Figures la, lb and lc are diagrammatic representations of a spoiler system including an actuator in accordance with an embodiment of the invention, in use, showing the spoiler system and actuator in three different operating positions; Figure 2 is an exploded view illustrating part of the system of Figure 1; Figure 3 is an enlarged perspective view illustrating part of the actuator of Figure 1; Figure 4 is a view similar to Figure 3 illustrating the actuator in a different position; Figures 5a, 5b, and Sc and Figure 6 are views similar to Figures land 2 illustrating an alternative embodiment; and Figure 7 illustrates some modifications to the arrangement of Figures 1 to 4.

Referring firstly to Figures 1 to 4 of the accompanying drawings, an actuator 10 is illustrated, the actuator 10 being arranged for use in controlling the movement of a spoiler 12 between stowed (see Figure la) and deployed (see Figure lb) positions, and an airbrake (see Figure 1c) position.

The actuator 10 comprises a guide plate 14 in which is provided a guide formation in the form of a guide slot 16. The guide slot 16 includes a main section 18 of generally straight form. Towards an end of the main section 18, the guide slot 16 is of forked or bifurcated form, defining a branched region in the form of an arcuate limb 20 that diverges from the main section 18. The arcuate limb 20 is of part circular form, the centre of curvature of which is located at substantially the adjacent end of the main section 18.

The actuator 10 further comprises a carriage 22 (commonly known as a nipple chamber) guided for movement relative to the guide plate 14. The carriage 22 comprises a main body 24 and a pair of follower members 26, 28, each of which projects through the guide slot 16. In this case, each follower member 26, 28 is of cylindrical form, but it will be appreciated that other shapes, such as polygonal shapes, could be used. The follower members 26, 28 form part of a plate 30 located to the opposite side of the guide plate 14 from the main body 24 whereby the carriage 22 is held captive to the guide plate 14. The spacing of the follow members 26)28 is substantially equal to the radius of curvature of the arcuate limb 20 of the guide slot 16. Whilst shown as part of the plate 30, one or other, or both of the follower members 26, 28 could form part of the carriage 22 or could be separate components, if desired. A pin or other fastener 26a extends through the carriage 22 and the first follower member 26, and a second pin or other fastener 28a extends through the carriage and into the second follower member 28, the pins 26a, 28a serving to couple the carriage 22 and plate 30 to one another so that the plate 30 and carriage 22 move as one. The follower members 26, 28 may be provided with bushes, bearings and/or lubricated to reduce friction, heat, vibration and/or noise, in use.

The carriage 22 has secured thereto a mounting bracket 12a whereby the spoiler 12 is secured to the carriage 22. The mounting bracket 12a is pivotally connected to the carriage 22 by way of the pin or other fastener 26a. It will be appreciated that the pin 26a transmits displacement of the carriage 22 to the mounting bracket 12a and spoiler 12, but permits pivotal movement of the carriage 22 relative to the bracket 12a, the bracket 12a remaining substantially parallel to the major axis of the guide plate 14, in use, in the arrangement illustrated. If desired, the mounting bracket 12a could comprise, for example a hollow pillar within which parts of the actuator are located, in use. An arm 12c interconnects the plate 30 and the spoiler 12 and serves to transmit pivotal movement of the carriage 22 to the spoiler 12.

The axes of the follower members 26, 28 generally intersect the centreline of the main section 18 of the guide slot 16, during deployment and stowing movement, but this need not always be the case and arrangements are possible in which the axis of one or other, or both, of the follower members 26, 28 are offset from the centreline of the main section 18, for example to enhance the packaging, vibration or acoustic properties of the actuator.

The main body 24 of the carriage 22 includes a hub 32 forming a cable engagement device. The hub 32 is defined, in part, by a pair of arcuate channels 34, 36, each of which terminates at a respective enlarged part. A first one of the channels 34 is of greater depth than the second one of the channels 36. An end part of a first drive cable 38 is received within the first channel 34, an enlarged head provided at an end of the cable 38 being located within the enlarged end part such that the cable is held captive thereto. The cable 38 extends from the carriage 22 around an idler roller or pulley 40 mounted upon an end part of the guide plate 14 close to the bifurcated part of the guide slot 16, and to a drive roller or cable drum 42 adapted to be driven for rotation by an electrically powered motor 44. An end part of a second drive cable 46 is received within the second channel 36 in a manner similar to the first cable 38. The second drive cable 46 extends directly from the carriage 22 to the drive roller or drum 42.

The cables 38,46 preferably take the form of Bowden cables or the like, but this need not always be the case.

The shape and location of the hub 32 is such that the run of the first cable 38 from the hub 32 towards the idler roller or pulley 40 and/or the run of the second cable 46 from the roller or drum 42 to the hub 32 is preferably offset from the main section 18 of the guide slot 16 with the result that a load applied to the carriage 22 by operation of the motor 44 to drive the roller or drum 42 for rotation will apply a torque to the carriage 22 urging the carriage for pivotal movement. However, as described below, for much of the time the manner in which the carriage 22 is guided for movement prevents rotation or pivotal movement thereof. Depending upon the application in which the actuator is used, this run of the cable 38,46 may additionally or alternatively be angled to the main section 18 of the guide slot 16.

The guide plate 14 is rigidly mounted, in use, upon a fixed part of a road car body. The carriage 22 is connected to the spoiler 12 as outlined hereinbefore.

In use, starting from the position shown in Figure la in which the spoiler 12 is in a stowed position, when it is desired to raise the spoiler 12 to a deployed position, the motor 44 is operated to drive the roller or drum 42 for rotation, the direction of rotation being such as to take up part of the first cable 38, the second cable 46 unwinding from the roller or drum 41 It will be appreciated that as a result the carriage 22 is drawn along the guide slot 16. As, initially, both of the follower members 26, 28 are located within the main section 18 of the guide slot 16, it will be appreciated that a path followed by the carriage 22, and hence that followed by the spoiler 12, is dictated by the shape and orientation of the main section 18 of the guide slot 16. In the arrangement illustrated, the main section 18 of the guide slot 16 is of straight form, and so the path of movement of the carriage takes the form of a linear translation in the direction of the main section 18. It will be appreciated, however, that this need not be the case and the path of movement of the carriage 22 may take other forms. For example, the main section 18 of the guide slot 16 could be of arcuate or S-shaped form, the path of movement of the carriage 22 being correspondingly shaped.

Provided the motor 44 continues to drive the roller or drum 42, the carriage 22 will continue to move along the path of movement defined by the main section 18 of the guide slot 16 until the first follower member 26 reaches the end of the main section 18, at which point the spoiler 12 will occupy its fully deployed position as shown in Figure lb. However, if desired, the motor 44 can be controlled in such a manner that the carriage 22 ceases movement before this point is reached. Operation of the motor 44 in the reverse direction results in the carriage 22 and spoiler 12 being driven back towards the stowed position shown in Figure la. Figure 3 illustrates the actuator 10 with the carriage 22 located at an intermediate position, part way along the length of the main section 18.

When the carriage 22 occupies the fully deployed position, the first follower member 26 is located at the end of the main section 18 of the guide slot 16, as mentioned hereinbefore, and the second follower member 28 is located at the point of intersection between the main section 18 and the arcuate limb 20. If, with the carriage 22 occupying this position, the motor 44 continues to be driven in the deployment direction then the carriage 22 will commence pivotal movement about the first follower member 26, the second follower member 28 following and being guided by the arcuate limb 20. As mentioned before, the provision and location of the hub 32 is such that a torque is applied to the carriage 22 driving the carriage 22 for such movement. The pivotal movement of the carriage 22 is transmitted to the spoiler 12 via the arm 12c. The pivotal movement continues until the second follower member 28 reaches the end of the arcuate limb 20, at which point the carriage 22 and spoiler 12 will occupy the airbrake position shown in Figure lc, unless operation of the motor 44 ceases before this point is reached.

If the carriage 22 has commenced the aforementioned pivotal movement, it will be appreciated that reverse operation of the motor 44 will result in reverse pivotal movement of the carriage 22 back to the fully deployed position (see Figure lb) and that once this position has been reached, continued reverse operation of the motor 44 will result in the carriage 22 moving towards the stowed position as mentioned above, following the aforementioned path of movement. Displacement of the carriage 22 back towards its stowed position cannot commence until pivotal movement of the carriage 22 to the fully deployed position has been completed as, up until this point is reached, the second follower member 28 will be located within the arcuate limb 20 of the guide slot 16, and as a consequence the first follower member 26 will be held at the end of the main section 18 of the guide slot 16, being unable to move therefrom.

In the arrangement described hereinbefore the carriage 22 is guided for movement by a pair of follower members 26, 28 that are capable of moving along a guide slot 16 of bifurcated form. However, other arrangements are possible. Figures 5 and 6 illustrate an arrangement in which the carriage 22 has only a single follower member 26 associated therewith. In this arrangement, the guide slot 16 includes a main section 18 but instead of being of bifurcated form it is instead provided, at an end thereof, with an end part 20a of enlarged width compared to the width of the main section 18. The end part 20a is conveniently of circular cross sectional shape.

Located within the end part 20a is a bush 20b. The bush 20b is of circular cross-section, matching that of the end part 20a, greater than the width of the main section 18 of the guide slot 16. As best shown in Figure 6, the outer periphery of the bush 20b is preferably of grooved form so as to positively retain the bush 20b within the end part 20a. It will be appreciated that the nature of the bush 20b is such that it is able to rotate within the end part 20a. Conveniently, as illustrated, a detent arrangement is provided to resist rotation of the bush other than when desired.

The bush 20b is provided with a cut-out or recess 20c shaped to receive the follower member 26 when the orientation of the bush 20b is such that the cut-out or recess 20c opens into the main section 18 of the guide slot 16.

The follower member 26 is of hexagonal cross-sectional shape, the spacing between two opposing faces thereof being substantially the same as the width of the main section 18 of the guide slot 16.

In use, the actuator is mounted in substantially the same manner as described with reference to Figures 1 to 4. Starting from the stowed position shown in Figure 5a, operation of the motor 44 drives the carriage 22 for displacement along the main section 18 of the guide slot 16. During this displacing movement, the cooperation between the sides of the follower member 26 and the main section 18 of the guide slot 16 serves to restrain the carriage against angular or pivotal movement without impeding the displacing movement. As with the arrangement of Figures 1 to 4, therefore, during this movement, the spoiler 12 will displace or translate between its stowed position (Figure 5a) and its fully deployed position (Figure 5b), following a path defined by the shape of the main section 18 of the guide slot 16, but will not undergo pivotal movement.

When the carriage 22 reaches the predetermined position defined by the end part 20a of the guide slot 16, the follower member 26 will enter the cut-out or recess 20c of the bush 20b. Once this position is reached, displacement of the carriage will cease as a result of the cooperation between the follower member 26, bush 20b and the end of the guide slot 16. If, in this position, the motor 44 continues to operate, the carriage 22 will pivot about the centre of the end part 20a, the follower member 26 and bush 20b being free to rotate or move angularly within the end part 20a. Such movement can continue until the airbrake position (Figure 5c) is reached. As shown in Figure Sc, movement beyond the airbrake position is resisted by engagement between part of the plate 30 or arm 12c and the guide plate 14, and the shape of the plate 30 can be selected to enable movement within a desired range. Furthermore, an up-stand or the like may be provided upon the plate 30 to prevent or restrict, for example, rotation of the carriage 22 and plate 30 in the wrong direction when the follower member 26 is received by the bush 20b.

From the airbrake position, reverse operation of the motor 44 will drive the carriage 22 for pivotal movement back towards the fully deployed position. Only once the fully deployed position is reached will the follower member 26 be able to exit the cut-out or recess 20c and follow the main section 18 of the guide slot 16 to return towards the stowed position. The return movement thus comprises pivotal movement as the actuator moves from the airbrake position to the fully deployed position, guided by the follower member 26 received by the bush 20b within the end part 20a, and displacing movement as the actuator moves from the fully deployed position to the stowed position, guided by the cooperation of the follower member 26 within the main section 18 of the guide slot 16.

Other than as described hereinbefore, the arrangement of Figures 5 and 6 is substantially the same as that of Figures 1 to 4 and so will not be described in further detail.

Whilst a follower member 26 of hexagonal form is shown, it will be appreciated that follower members of other non-circular shapes may be used. Potentially, the shape of the follower member 26 may be chosen so as to prevent or restrict, for example, rotation thereof in the wrong direction when received by the bush 20b.

In the arrangements described hereinbefore the carriage 22 is arranged to undertake displacement or translational movement and, once a predetermined position is reached, to undertake pivotal movement. However, arrangements are also possible in which displacement and pivotal motion take place simultaneously, the net movement of the carriage being a compound of the displacement and the pivotal movement. By way of example, Figure 7a illustrates the guide slot 16 of an arrangement similar to that of Figures 1 to 4 but in which the curved limb 20 is not of part circular form, centred upon the end of the main section 18 but instead is of non-circular shape. As a result, initially the carriage 22 undergoes displacing movement but once it reaches a position at which the second follower member 28 aligns with the end of the curved limb 20 the second follower member 28 enters and follows the curved limb 20 whilst the first follower member 26 continues to be guided by the main section 18. The shape of the limb 20 may be such that the carriage 22 then undertakes a compound of displacement and pivotal motion. Alternatively, the carriage 22 may undergo pivotal movement and subsequently recommence displacement.

Figure 7b illustrates an arrangement in which the first follower member 26 follows a curved limb 20 whilst the second follower member 28 continues to follow the main section 18. Figure 7c illustrates an arrangement in which the first and second follower members 26, 28 are guided for movement by respective guide slots shaped to define a chosen path of movement. In each case, the net movement of the carriage 22 may be a compound of displacement and pivotal movement, if desired.

It will be appreciated that the actuators described hereinbefore are advantageous in that a single motor can be used in conjunction with the actuator to achieve both displacement or translational movement, in this case between the stowed and deployed positions, and to achieve pivotal movement. As a consequence, significant weight and associated cost savings can be made. If required, a pair (or more) of such actuators may be driven from a single motor. Accordingly, the spoiler 12 may be supported by and driven for movement by a pair of such actuators, and as the actuators are driven from a common motor, their operation will be synchronised.

Whilst the actuators are described in relation to an active spoiler of a road car, it will be appreciated that the invention is not restricted in this regard. They may be used in other vehicle related applications, for example in driving the wing mirrors thereof for movement, driving the glass of a window regulator, for moving body parts thereof, for example to provide active aerodynamics, for adjusting the vents of a heating or air conditioning system, or adjusting seating within the vehicle. The actuators may also be employed in a range of other, non-road vehicle related applications.

Although described as using two cables, it will be appreciated that these may in fact comprise respective end regions of a single cable.

The description hereinbefore relates to certain specific embodiments of the invention. It will be appreciated, however, that the invention is not restricted to the arrangements described herein and shown in the accompanying drawings, but rather that a number of modifications and alterations may be made thereto without departing from the scope of the invention as defined by the appended claims. The arrangements described and illustrated are simplified for clarity. Depending upon the requirements of the application in which the actuator is to be used, changes may be made to the actuator, for example to make weight savings or enhance the load bearing capacity thereof, or to suit a manufacturing technique by which it is made. These changes may include, for example, incorporating cavities, varying edge and corner radii, incorporating strengthening ribs, and changing draft angles and/or chamfers or the like. It will be appreciated that this is a non-exhaustive list of changes that can be made.

Claims

CLAIMS: 1. An actuator comprising a guide, a carriage cooperable with the guide and guided for movement thereby, the guide defining a region adapted to guide the carriage for displacement along a path and to guide the carriage for pivotal movement.
2. An actuator according to Claim 1, wherein the carriage is guided for pivotal movement at a predetermined position along the path.
3. An actuator according to Claim 1 or Claim 2, wherein the path is a linear path.
4. An actuator according to any of the preceding claims, wherein the predetermined position at which the carriage is guided for pivotal movement is at an end of the path.
5. An actuator according to any of the preceding claims, where the carriage is arranged to be driven for movement relative to the guide by a cable drive arrangement.
6. An actuator according to Claim 5, where the cable drive arrangement comprises a motor driven cable drive arrangement.
7. An actuator according to Claim 5 or Claim 6, wherein the operation of the cable drive arrangement drives the carriage for movement along the path, continued operation thereof once the carriage has reached the predetermined position driving the carriage for pivotal movement.
8. An actuator according to any of the preceding claims, wherein the guide includes a guide formation cooperable with first and second follower members provided on the carriage to guide the carriage for movement.
9. An actuator according to Claim 8, wherein the guide formation comprises a guide slot.
10. An actuator according to Claim 8 or Claim 9, wherein the guide formation is of bifurcated form, including a main section serving, in use, to guide the carriage for movement along the path, and a branched region serving, in use, to guide the carriage for pivotal movement.
11. An actuator according to Claim 10, wherein in the branched region, the guide formation includes a limb of part circular form, the centre of curvature of the limb being centred upon an end part of the main section.
12. An actuator according to any of Claims 1 to 7, wherein the guide comprises a guide formation with which a single follower member is cooperable, the follower member being of non-circular cross-section, and the guide formation comprising a slot or channel including a main part and an end part of enlarged width compared to the main part such that when the follower member is located at the predetermined position at the end part, angular movement of the follower member relative to the guide formation is permitted, such pivotal movement being resisted when the follower member is not located at the predetermined position.
13. An actuator according to Claim 12, wherein the follower member is of polygonal form, opposing ones of the sides thereof bearing against the guide formation when the follower means is not located at the predetermined position to resist angular movement of the follower member, the follower member being able to move angularly when located within the end part.
14. An actuator according to Claim 13, wherein the follower member is of hexagonal form.
15. An actuator according to any of Claims 12 to 14, further comprising a bush located within the end part and adapted to receive the follower member.
16. An actuator according to any of Claims 8 to 15 when dependent directly or indirectly upon Claim 5, wherein the carriage has provided thereon a cable engagement device designed such that a point of contact between a cable of the cable drive arrangement and the cable engagement device is offset from the path followed by the follower member(s) when following the path.
17. An actuator according to Claim 16, wherein the cable engagement device is cooperable with a pair of cables or cable regions, one to drive the carriage in one direction and the other to drive the carriage in the reverse direction.
18. An actuator according to Claim 17, wherein the cables or cable regions are driven by a common motor.
19. An active spoiler system comprising a spoiler and at least one actuator according to any of the preceding claims and positioned and operable to drive the spoiler for movement between a stowed position and a deployed position, and once in the deployed position, to drive the spoiler between the deployed position and an air brake position.
20. A window regulator system comprising a glass panel and at least one actuator according to any of the preceding claims and positioned and operable to drive the glass panel for 25 movement.