WO2012117217A1

WO2012117217A1 - Cam driven movement mechanism

Info

Publication number: WO2012117217A1
Application number: PCT/GB2012/000196
Authority: WO
Inventors: Steven Corcoran
Original assignee: Corcost Limited
Priority date: 2011-02-28
Filing date: 2012-02-28
Publication date: 2012-09-07
Also published as: GB201103411D0

Abstract

A cam driven movement mechanism comprising a position adjustable surface having an associated movement mechanism operable to effect changes in the position of the surface relative to a reference plane, the movement mechanism comprising at least one cam and wherein the surface is supported by the at least one cam such that rotation of the at least one cam results in movement of the surface relative to the reference plane and a control system reactive to an external stimuli to effect movement of the cam, and so reposition the surface.

Description

CAM DRIVEN MOVEMENT MECHANISM

The present invention relates to a novel cam driven movement mechanism for use in adjusting the height and orientation of a surface or surface portion about one or multiple axes. More particularly, the invention relates to such a mechanism which can be manipulated through an associated control system to react to external stimuli.

The movement mechanism of the invention has multiple applications; which include, without limitation; seating adjustment, solar panels, adjustable bed surfaces, vehicular armour and other military applications, ship hulls, vehicle body work and houses. The present invention can be particularly useful in surface self-levelling, for example (but again without limitation); of robotic pallets, stands, lifting jacks, moveable platforms and tables. Yet further applications include active ride vehicle applications for example (again but without limitation) in ships, tanks, amphibious vehicles, helicopters, aeroplanes, sub marines and automotive vehicles. In each of the described type of application, it is to be appreciated that the movement mechanism is operable to perform changes of position and orientation of a surface about one or multiple axes and this can be in reaction to an externally applied load and/or occurrence such as a motion whereby the motion can be of vertical lift, pitch, roll and yaw or combinations of those movements.

Multiple, modular cam driven sub sections may be arranged in any of a variety of different configurations to suit the desired range of movement for the chosen application.

In prior published International patent application publication no WO2005018522 (Al) entitled "Raiser Seat", the Applicant describes a cam driven movement mechanism embodied in a raiser seat. The present invention seeks to improve and adapt the mechanism described therein to facilitate use of a cam driven movement mechanism in a wider range of novel applications.

Figures 6 to 15 of International patent application publication no WO2005018522 (Al) and their accompanying description illustrate various embodiments of a cam driven movement mechanism, the features of which are all of equal relevance to this present application. In accordance with the present invention there is provided a cam driven movement mechanism comprising a position adjustable surface having an associated movement mechanism operable to effect changes in the position of the surface relative to a reference plane, the movement mechanism comprising at least one cam and wherein the surface is supported by the at least one cam such that rotation of the at least one cam results in movement of the surface relative to the reference plane and a control system reactive to an external stimulus to effect movement of the cam, and so reposition the surface.

The term "cam" as used herein includes single and multiple bladed, lever-type cams and linear actuator cams. Lever-type cams can have one or more tracks, conveyers, rollers/casters/wheels, roller type or plain bearings, or linear slides that act to set the effective profile of the lever, thus achieving the same function as a cam. A linear actuator cam comprises a cam adjustable by means of a linear actuator where the linear actuator can be operated by an electric or fluid system and typically (but not limited to) the activation of the electric or fluid powered linear actuator will linearly move the cam (or part thereof) in either of a first or second direction.

Multiple layers can or at least one cam driven surface can be positioned on top of each other to form multiple stacked layers.

Movement of the surface relative to the reference plane can be in any of one, two or three dimensions.

The reference plane may comprise a second surface and the mechanism is optionally configured such that each of the first and second surfaces can be repositioned respectively to the other.

The control system can take a range of forms, in one simple embodiment, the movement mechanism comprises a cam with multiple blades (for example as shown in Figure 9 of WO2005018522 (Al) ) As described in relation to Figure 9 WO2005018522 (Al), individual cam blade sections are interconnected by sprung connections positioned either side of the centre line about which the blade sections pivot. In a simple example of the present invention, the resiliency of the sprung loaded connections can be varied between blade sections so as to ensure a preferred reaction to a predefined external stimulus. In a more complex arrangement, a control system incorporates sensors monitoring external stimuli which exert some load on the surface and/or cam blade and actively changes the properties of one or more sprung loaded connections so as to bring about a preferred response of the surface to the exerted load resulting from motion or other stimuli.

Each cam blade or cam blade section can be made resiliently adjustable by means of any one or more of; springs, flexible blade material and sprung members. Desirably, a more complex control system enables individual cam blade or blade sections to be influenced individually and relative to other cam blade or blade sections arranged for adjusting the surface. In one specific, illustrative example, the surface is a seat in a moving vehicle. A user can be sat on the seat and the cams and/or cam blade sections arranged for adjusting the position of portions of the seat surface can be such that they will allow an amount of movement and as such, as the vehicle moves, the seat occupant will be cushioned against, for example, undulations in the surface over which the vehicle is travelling or other external stimuli. Adjustment of the cam blade or blade sections may be influenced in response to load sensors detecting, for example, loads resulting from a sharp turn, significant undulations and cambers of the road surface on which the vehicle is travelling, heavy braking or impact with another object or vehicle. The control system responds to the load sensors to reposition individual cam blade or cam blade sections so as to move an associated portion of the seat so as to counter or exaggerate an expected movement of the seat occupant in response to the sensed loads, thereby to maintain the occupant in a relatively stable and constant seating position. For example, the system may react so as to move an occupant away from a point of impact of the vehicle with another object, or to resist lurching of the seat occupant as a vehicle turns a corner at speed.

Various methods for controlling the movement mechanism are possible.

For example, but without limitation the control system could connect with an existing fluid flow system, in the case of a motor vehicle, this could be a hydraulic or pneumatic system provided with the specific purpose of controlling the movement mechanism or alternatively, an existing system, for example the car braking, or suspension system could be adapted to serve a dual purpose as part of the control system of the invention. For example, fluid could be selectively diverted to all or selected parts of the movement mechanism to influence pneumatic or hydraulically operated linear actuators for adjusting the relative separation of cams or cam blade sections. In a more complex example, fluid could be selectively diverted to all or selected parts of the movement mechanism to influence the resiliency of a spring loaded connection through a change in viscosity and/or pressure about the connection or through force introduced by directional fluid flow and this could alter the resistance to movement of a fluid driven linear actuator.

In another alternative, the control system might use electrical or electromagnetic impulses to adjust the cam blade or blade sections, whether by directly affecting the speed/extent of rotation of an electrical controlled actuator, or through introduction of magnetic fields which influence movement of parts of the movement mechanism in or associated to the at least one cam and/or its rotation in turn repositioning the cam blade or blade sections and hence the surface.

In other examples, the control system could act to reversibly alter the physical characteristics of a cam blade, blade section, or connector between blades or blade sections, for example by the introduction of a magnetic field, heat or electrical charge.

Optionally, the cam blade can be configured to be length adjustable, for example by the incorporation of at least one element arranged to be extendable and/or retractable with respect to a main body of the cam blade. Adjustment of the cam length can be controlled to influence the positioning of the surface. For example, the extendable and/or retractable element may be connected to the main body by a sprung connection. This enables the cam to change length and profile and act with a sprung capability. As discussed above, it is possible for the characteristics of the sprung sections to be altered by fluid, for example in reaction to a change in the movement or pressure characteristics of the fluid.

The various described embodiments of the cam operated mechanisms of the present invention are distinguished from that described in WO2005018522 (Al) by the incorporation of a number of additional features; firstly the multiple cam units are able to be self contained, secondly some embodiments incorporate novel locking members and third the individual units can feature the ability to connect to a separate guide system respective to the orientation of the cam. By way of example, the cam driven movement mechanism of the invention is now further described with reference to the accompanying Figures in which;

Figure 1 shows a plan view of a cam operated movement mechanism excluding surfaces and rods.

Figure 2 shows a side view of the cam operated movement mechanism of Figure 1 including surfaces and rods.

Figure 3 shows a plan view of a cam system.

Figure 1 shows a cam operated movement mechanism 1, the cam operated mechanism can be connected between two surfaces and the basic mechanism is broadly based on the cam operated movement mechanism that is described in the Applicant's prior published International patent publication no. WO2005018522 (Al) entitled "Raiser Seat".

In this specific example, the two surfaces are a seat and seat base, for example, of an automotive vehicle. It is to be appreciated though that the application of the mechanism is not limited to automotive seating. The illustrated cam system consists of a cam 3, the case of the unit 2 holds all the cam components and can be a sealed unit providing a means for the cam blade to exit in at least one direction. Typically the cam can exit in both directions (anticlockwise and clock-wise direction) and exit from the top and bottom of the casing.

The cam system has an actuator 4 that is connected permanently or removably to a Ieadscrew 5, whereby the Ieadscrew is held with bearings 6 and 7. Conveniently (though not essentially) the actuator is an electric motor and can feature front mount additional bearing. A bearing 7 features a wear plate 8 which can be sprung loaded whereby to maintain a constant pressure on the Ieadscrew bearing 6 and subsequently the Ieadscrew 5 whereby the pressure can adjust as the bearing and/or Ieadscrew wears and so reduce noise. All bearings referenced in the figures and general description can be plain or ball bearings, needle or roller bearings or any other type of bearing suitable to the application and known to those skilled in the art.

The nut 9 is meshed on the leadscrew 5 and thus rotation of the actuator 4 will rotate the leadscrew 5 and move the nut 9, via its meshed relationship with the leadscrew 5, linearly along the leadscrew's axis. The nut 9 is permanently or removably attached and more typically integrated to the toothed section 10 which is meshed with the gear 11. Therefore the linear movement of the nut 9 and consequent linear movement of the toothed section 10 rotate the gear 11 with relation to the rotation of the actuator 4. The toothed section 10 meshes with a rear gear assembly via the toothed extension 12, the gear assembly conveniently (but not essentially) features a gear and shaft 13 which are desirably fully integrally formed, though the gear may be fixedly or removably attached to the shaft.

The shaft is located on at least one bearing 15 where 14 is a spacer between the bearing, gear shaft 13 and the casing 2. As the toothed section 10 moves linearly, as well as rotating the gear 11, the gear and shaft 13 will also rotate and thus they will act as a secondary alignment gear.

The cam blade 3 as shown has an integrated shaft but in practice, the shaft could be fixedly or removably attached to the blade. Similarly, the drive gear 11 can be removably or fixedly attached or integrated to the cam shaft. The toothed section 12 is an extension to the toothed section 10 and it is this part that meshes with main drive toothed section 10.

The cam shaft has two ends 16 and 17 are each supported with a bearing 18 and 19. A further bearing can optionally be placed closer towards the cam blade 3. In the Figure that is shown as the bearing 20. As the actuator 4 rotates, and moves the toothed sections 10 and 12 linearly, the gear 11 to which toothed section 10 is meshed (which gear may be integrated with the cam shaft and/or the cam blade 3, or permanently or fixedly attached to the cam blade and/or cam shaft). The gear 11 is caused to rotate and in turn rotates the cam blade 3 in either of two directions, depending on the direction of rotation of the actuator. The cam blade 3 has at least one roller and/or bearing and/or other low friction member, in the Figure two rollers are shown 21, 22. The profile of the cam is relative to the points at which the rollers (or alternative low friction member) are located relative to the cam shaft axis, the action of the cam shaft and the action of the cam blade whereby it is possible to change the length and/or form and/or shape of the cam blade 3. For example, a linear actuator may be incorporated into the cam and adjusted by the control system to bring about a separation adjustment between elements of the cam in one or more of three planes.

It is also possible for the cam blade 3 to comprise multiple blade sections with each section being movable independently and optionally sprung loaded individually with relation to a remote point or with relation to each other. As described already, the cam blade can also feature at least one component that allows the cam blade to be altered and/or form and/or shape as well as vary position in response to stimuli.

In an alternative arrangement (not illustrated), the cam blade 3 may have at least one section with multiple rollers and/or other low friction members, which might, for example, include bearings or a cam blade with an in built piston and/or linear actuator. Each of the sections and associated low friction member is desirably arranged to move independently such that each blade section, as well as the cam blade as a whole, has the ability to absorb loads. The multiple blades or blade sections can individually be configured with selectively chosen low friction members which may vary in properties from blade to blade or blade section to blade section. As such, each cam blade or cam blade section is configured to respond differently to a given load applied to the mechanism, for example by having different capacity to absorb energy and/or loads. As a result, when the surface is subjected to a given load, a variable response to the load occurs across the surface.

In one embodiment, the cam blade and/or at least one blade section can be mounted on a central shaft and the cam blade and/or at least one blade section are able to rotate about the centre axis of the central shaft, however, they are also able to operate in an off set manner and thus, under load, the cam blades and/or blade sections can move different and absorb loads differently, even in the absence of the previously described length/form/shape changing feature.

The cam blades can be in sections and can be used with other cam blades (as is detailed in the description of WO2005018522 (Al) with reference to Figure 9 of that publication) and as such the orientation of the cam units 2 can be positioned between two surfaces. Therefore, with regards to the cam blade and its sections, as one cam blade goes under a specific load then another blade or blade section connected thereto can deform and/or change and/or move (depending on which embodiment is used) proportionate to the characteristics of that blade or blade section.

The connected blade or blade section can then deform and/or change and/or move proportionately to the characteristics of that blade or blade section and thus another connected cam blade or blade section can be exposed to the load and so on and so forth. This arrangement is of high practicality, for example, if a body is situated on a surface embodying the mechanism as described, under a given load director and/or magnitude (which, where the arrangement is embodied in a moving vehicle for example, could come from a high energy impact), responsive to the direction of impact and resultant load from the movement of the body with respect to the surface, the cam blade or blade sections are caused to deform and/or change form or shape, and/or move proportionate to the characteristics of that cam blade or blade section and thereby absorb the load and/or energy as well as reposition the body via the adjustment of the cam blades and/or cam blade sections, whether with respect to their length, position in any of up to three dimensions, or by sprung positional adjustment as described.

To summarise, the cams, cam blades and/or cam blade sections and their relative orientations, can be selectively and individually designed to manipulate the positioning of a body carried on the surface, whereby to continually maintain that body in the best position to withstand an impact or other external load. With particular regard to persons carried in motor vehicles, the mechanism can be designed to account for other interactions, for example, to control the positioning of a seat occupant in the event of deployment of an air bag.

As has been described, each cam blade or cam blade section can be configured to feature springs and/or flexible material and/or sprung members and/or fluid operated sprung or length changing capabilities. The properties of the cam blades or cam sections and/or length changing capabilities can also be configured such that they collectively can provide cushioning between two opposing surfaces, for example on opposing surfaces of a seat cushion. That is to say that a user can be sat on the seat, for instance in a motor vehicle, and the cams or cam blade sections can be configured such that they allow an amount of movement such that as the vehicle travels, the user is cushioned against undulations in the road surface over which the vehicle is travelling. This principle can also be adapted to seating or bedding in passenger transport on any of a ship, aircraft, truck, tractor, fork lift, military ground vehicle, motorcycles, mobility scooters, patient transport trolleys, or any other type of passenger or load carrying vehicle.

The arrangement described also has application in other unconnected sectors. One such sector is that of the solar panel market where the at least one cam can be arranged under a solar panel such that the cam or cams or cam blade sections can be adjusted and the panel controlled to follow the sun (track the sun). In this circumstance and with ability for at least one cam blade and/or at least one cam section to have a flexural quality either through choice of material or additional sprung element(s), or length change mechanisms as described previously, if a sudden gust of wind is present then the cam blades and or sections can allow a limited movement. This means that the systems are not exposed to sudden shocks in terms of forces resultant from the wind or other environmental factors and this helps protect the cam systems, the solar panel and all other associated assemblies.

In another application, any already described embodiment of the mechanism of the invention can be used with regards to a child safety seat. The child safety seat can be placed on top of the cam system instead of the car base seat, the child safety seat can be of any known form, for example, a booster seat, carry cot or modular element of a baby transport system. Applying the principles already described, the load parameters of the mechanism can be configured with respect to a given impact or other significant load to absorb energy and maintain a relatively stable position of the child occupying the seat as well as minimise any velocity changes in terms of any direction of acceleration. Again as described above, the cam or cam sections can be configured such that during a "loading" period, the occupant of the seat (the infant) can be supported throughout the loading and unloading periods respective to an impact. Once further referring to the above, the cams can be used with regards to the general sprung nature of the unit and thus the at least one cam blade or section can be used to absorb forces generated from, for instance but without limitation, undulations in the road. The cam seat can also be used for a motorbike seat however the layout of the cams can be different but all the above qualities and properties, functions and features can be applied where desired. An illustrative example is given in Figure 2.

The cam blade shown (but is not essentially so) has two rollers or bearings 21 and 22 that may be fixedly or removably attached to the cam via shafts. As shown, the shaft 23 has an extension shaft which fits into a channel within the member 24. Conveniently but not essentially, two members 24 are present, one top and one bottom. The members 24 are typically integrated with the surfaces 35 and 36, with the base or bottom surface 36 for the bottom located member and the top surface 35 for the top located member. Therefore as the cam blade or cam section rotates in a first direction, the extension of the shaft 23 becomes engaged but does not need to touch the sides of the channel in the top member 24. As the cam blade or cam section rotates in a second direction, the extension of the shaft 23 becomes engaged but does not need to touch the sides of the channel in the bottom member 24.

The top and bottom members 24 are conveniently but not necessarily integrated into the base surface and the top surface respectively. This means that the at least one cam blade can operate in both directions and become engaged within a channel. The channel can be of any suitable profile and can be an open channel or closed channel and/ or it could have open and closed sections.

Each cam unit can be provided with at least one lock, most practical applications envisaged conveniently utilise no or four locks. Where locks are present, the cam casing can be fixedly or removably attached to the top surface or bottom surface. The locks may be fixedly or removably attached to the cam casing or alternatively integrally formed with the cam casing.

The figure shows two locks 25 and 26. The locks work in the same manner, for example, an actuator 27 is connected permanently or removably attached to a leadscrew 28. The leadscrew is meshed with a nut 29 which at least partially contained within the casing. External to the casing the nut 29 typically has an expanded section 30 wherein the expanded section 30 has a blind or through hole 31. The leadscrew typically has at least one further bearing 32 located relatively distal to actuator 27. The actuator 27 is, for example (but not essentially), an electric motor and when attached to the leadscrew assists in the support of the leadscrew relative to the motor's location, however a further bearing 33 can be located generally towards the attachment of the motor and kadscrew. The casing has a slot 34 and as such, as the actuator 27 rotates, the leadscrew 28 rotates and this in turn moves the nut 29 linearly along its axis. This linear movement is then applied to the external nut section 30 whereby the nut 29 linear direction is relational to the rotation of the actuator 27.

The casing of the lock 26 or 25 may further include a circuit board incorporating or arranged to communicate with sensors (not shown), which monitor parameters indicative of the lock being open or closed. Data from the sensors can be processed by a central processing unit identifying whether or not the lock is engaged. Conversely the locks can be controlled by the central processing unit.

The locks can be orientated differently to each other and typically the orientation's respective to the location of the holes 31. The slot 34 yields a further function in that the react of the slot to the nut 29 and in particular the external nut section 30 means that the slot and casing of the lock 26 or 25 inhibits the nut and external section ability to rotate and as such work to enable linear nut translation from leadscrew rotational input.

The locks can be attached to the cam casing or attached to either the top or bottom surfaces between which the at least one cam is located. However, more typically at least one lock and typically two locks are attached to the casing of the cam, they can be fixedly or removably attached or they can be integrated with the cam casing.

Each of the surfaces (the top and bottom surface) can feature rods 37, where the rods are located respective to the linear movement and relative position of the holes 31. The rods can be fixedly or removably attached to the surfaces or integrated with the surfaces include a rod flange. Generally, as the actuators 27 in the locks rotate and the nut 29 and therefore the hole 31 moves linear in a first or second direction, the hole 31 will engage with the at least one rod and, depending on the orientation of the locks and in particular the holes, the locks either engage with the at least one rod of the top surface or engage with the at least one rod of the bottom surface. Alternatively however, the holes could engage with either the rods of the top and bottom surface respective to the relative position of both the holes and rods and the axial orientation of the hole axis. For ease of explanation, in the illustrated embodiment, each lock will engage with a rod from either the top or the bottom surface. In this scenario, the first lock's nut 29 and hole 31 is moved in a first direction and as such the first lock's hole engages with the bottom surface's rod whilst the opposite occurs with the second lock's hole, where the hole disengages with the top surface's rod and as such the cam is locked to the bottom surface. It will be appreciated that this can be reserved such that the second lock's hole engages with the top surface's rod whilst the bottom surface's rod sees the first lock disengage from its rod.

This locking arrangement allows for the at least one cam unit 2 to be selectively associated with the top surface or the bottom surface 36 as required and as such allows the at least one cam blade and or at least one cam blade section to rotate in either of a first direction to lift the top surface with the cam units attached or in a second direction without the cam units attached.

In more detailed terms, the locking arrangement allows at least one cam unit to be locked to the bottom surface and as the at least one cam unit 2 operates, the at least one cam blade and/or at least one cam blade section rotates in the first direction. Thus the top surface and all associated with it will be raised in accordance with the profile of the at least one cam (or at least one cam blade section) relative to the profile of any other.

The locking arrangement allows at least one cam unit to be locked to the top surface and as the at least one cam unit 2 operates, the at least one cam blade (or at least one cam section) rotates in a second direction, the top surface and all associated with it will be raised in accordance with the profile of the at least one cam (or at least one cam blade section) relative to the profile of any other, however, in this configuration, in contrast to the first described configuration, the cam units will actually move with the top surface 35.

As has been commented, the at least one cam blade or section can rotate clockwise or anticlockwise. Above, reference has been made to first and second directions which reference the clockwise or anti-clockwise movement of the at least one cam blade or section. As the cam blade or section moves in either direction, the extension of the at least one shaft 23 is able to engage the hole in either of the top or bottom member 24 depending on the direction of rotation.

Referring to Figure 3, the cam system that can feature at least one cam unit 38, 40, 44 and 46 each of which can have all the same functions and features as the cam system 1 described in Figure 1 and 2. Each of the cam systems can be selectively retained against a first surface and retained against a second surface as also described in Figure 1.

Therefore, if the at least one cam rotates in a first direction then the first surface will move away from the second surface, whereas if the at least one cam rotates in a second, opposite direction, the second surface will move away from the first surface. In a practical embodiment, the first surface can be, for example but without limitation, a solar panel or a motorbike seat and the second surface a frame whereby each cam (in the illustrated example, totalling four) can move independently or in synchronisation with at least one of the other cams at the same or a different speed and in the same or a different direction. Thus, a solar panel or motorbike seat is able to be moved in a purely vertical manner, or with at least one earner or edge higher or lower than at least one other corner or edge. Consequently, the seat or solar panel can be moved in a first or second direction whilst maintaining a desired, set, unset or dynamically changing angle or orientation.

The at least one cam unit can be effectively connected to least one other cam unit via a drive shaft and typically at least one gear. The drive shaft orientation and/or position and/or number can be varied from that illustrated here without departing from the scope of the invention. The system below simply illustrates in a very simple form how a drive system can be used to connect the cam unit. In this non limiting example, the drive system is shown associated with manual cam units. A drive shaft 39 connects cam units 38 and 40 whilst a drive shaft 45 connects units 44 and 46, The drive shafts 39 and 45 can be connected by the drive shafts 41 and 43 and the drive shafts 41 and 43 can be connected to the drive shaft 42 where all drive shaft connections are made via at least one meshed gear. Thus the rotation of the drive shaft 42 rotates drive shafts 41 and 43 which in turn rotate the drive shafts 39 and 45 which connect to the leadscrew 5 of the respective cam unit and as such rotation of the drive shaft 42 will result in the rotation of the at least one cam in each of the cam units. The profile and position of the cam in each cam unit can be fixed according to requirements such that the first or second surface will always feature a permanent or non-permanent incline or decline or angle.

The cam systems can also be connected to the braking system of a motor vehicle and as such, as the vehicle's brakes are activated, it can be arranged, for example through a system of controlled valves, that fluid from the braking system or an associated and closed fluid system, could be selectively diverted whereby to alter the relationship between the cams such that either the first or second surface will, for example, become inclined or at least one at least one edge or corner is raised relative to another. Alternatively, the cams could be altered by the activation of an electric motor as described or other means such as a fluid cam configured to allow fluid to leave at least one chamber and as such change the cam's profile, however, many such systems can be used to adjust the at least one cam relative to at least one other cam and thus incline at least part of the seat.

Claims

1. A cam driven movement mechanism comprising a position adjustable surface having an associated movement mechanism operable to effect changes in the position of the surface relative to a reference plane, the movement mechanism comprising at least one cam and wherein the surface is supported by the at least one cam such that rotation of the at least one cam results in movement of the surface relative to the reference plane and a control system reactive to an external stimulus to effect movement of the cam, and so reposition the surface.

2. A cam driven movement mechanism as claimed in claim 1 wherein the cam comprises multiple blade sections interconnected by sprung loaded connections positioned either side of the centre line about which the btede sections pivot and wherein the resiliency of the sprung loaded connections is varied between blade sections and selected so as to ensure a preferred reaction to a predefined external stimulus.

S. A cam driven movement mechanism as claimed in claim 1 or claim 2 wherein the control system comprises sensors configured to monitor external stimuli which exert some load on the surface and/or cam blade and a controller which interprets and responds to data received from the sensors actively to adjust the position of one or more cams of the movement mechanism so as to bring about a preferred response of the surface to the exerted load.

4. A cam driven movement mechanism as claimed in claim 1 or 3 wherein the control system incorporates a fluid flow system and a controller for selectively diverting fluid within the system in reaction to external loads.

5. A cam driven movement mechanism as claimed in claim 4 wherein the surface comprises a vehicle seat and the fluid control system is associated with the vehicle's breaking system.

6. A cam driver) movement mechanism as claimed in claim 4 wherein the fluid flow system serves solely as part of the control system.

7. A cam driven movement mechanism as claimed in claim 4 wherein the fluid flow system interacts with a pneumatic or hydraulic control for adjusting the length, form, shape or position of the cam.

8. A cam driven movement mechanism as claimed in any preceding claim wherein the surface is selected from; a seat, a bed, a solar panel, a retractable roof or hood, a lifting pallet, an adjustable platform or walkway, the floor or seat of a land sea or air travel vehicle.

9. A cam driven movement mechanism as claimed in any preceding claim comprising multiple cam assemblies, each independently operable to adjust the position of the surface or a portion of the surface wherein the cam assemblies are mechanically interconnected and share a common control system.

10. A cam driven movement mechanism as claimed in claim 9 wherein the cam assemblies are ail driven by a single drive.

11. A cam driven movement mechanism as claimed in any preceding claim wherein the cam blade is reversibiy lockable to either or both of the surface and a surface of the reference plane.

12. A cam driven movement mechanism as claimed in claim 11 wherein the reversible lock comprises a locking mechanism consisting of an actuator operable to rotate a leadscrew to which is threaded a nut, the leadscrew and nut being enclosed by a casing, the casing having a channel through which a radial extension of the nut protrudes, whereby on rotation of the leadscrew, the nut is driven linearly along the leadscrew, the radial extension of the nut being provided with a bore configured to engage a compatible protrusion extending from the surface to which the cam blade is to be locked.

13. A cam driven movement mechanism as claimed in claim 11 or claim 12 wherein mechanism comprises a second surface and at least two reversible locks whereby the cam can be selectively locked to either surface.

14. A cam driven movement mechanism as claimed in claim 13 comprising four reversible locks, two of which are selectively lockable to each of the two surfaces.

25. A seat having a seat surface and incorporating the cam mechanism of any of claims 1 to 14 foradjusting the position and/or orientation of the seat surface.

16. An armoured vehicle including at least one, optionally a plurality of armoured panels which are each supported by the cam mechanism of any of claims 1 to 14, such as to provide for changes in position and/or orientation of the panels.

17. The vehicle of claim 16, wherein each panel is a reactive armoured panel and the associated cam mechanism changes the position and/or orient of the panel in dependence upon a detected factor, optionally an environmental factor, such as incoming munitions.

18. A vehicle including at least one, optionally a plurality of panels which are each supported by the cam mechanism of any of claims 1 to 14, such as to provide for changes in position and/or orientation of the panels, optionally to configure a visual and/or aerodynamic profile of the vehicle.

19. The vehicle of claim 18, wherein each panel is a reactive panel and the associated cam mechanism changes the position and/or orient of the panel in dependence upon a detected factor, optionally an environmental factor, such as location and/or speed.