Control system for a closure

Abstract

 A control system for a closure (1) such as an automotive door pivoted on hinges (3 and 4) comprises a torque sensing device (7) that monitors the operating torque applied to the closure (1), a movement sensing device (8) for monitoring movement of the closure (1) and a logic controller (6) responsive to the signals from the sensing devices (7 and 8) to cause a restraining mechanism (5) to apply or release a braking force to the closure (1). The control system prevents movement of the closure (1) until a pre-determined operating force is applied to the closure (1) and applies a braking force to the closure (1) when movement of the closure (1) is slower or faster than pre-determined speeds.

Description

[0001] This invention relates to a control system for a closure such as a door and in particular, but not exclusively to a control system for a vehicle door.

[0002] Controlling opening movement of vehicle doors is required to prevent damage to the door and/or to a surface which the door comes into contact with, for example the door of another vehicle when two cars are parked next to each other.

[0003] It is already well known to employ a door check of the kind in which a link in the form of strap adapted to be pivotally connected at one end to a door frame is withdrawn through a housing mounted on a complementary part of the door and has a stop at the other end to limit opening movement of the door.

[0004] The movement of the link is typically subject to a restraining force which may be provided by a spring loaded roller on one of the link and housing and co-operable with the other of the link and housing to provide frictional restraint to opening movement of the door.

[0005] The known door checks commonly allow the door to open up to a maximum of 60° relative to the vehicle body and the door may be held in one or two intermediate open positions, for example at 30° and 45° to the vehicle body, by engagement of the spring loaded roller in complementary recesses.

[0006] A disadvantage of the existing door checks of this type is that the door can only be held open at pre-determined positions according to the position of the end stop and any recesses for engagement with the spring loaded roller.

[0007] It can often happen that such pre-determined positions do not correspond to the extent to which the door can safely be opened without coming into contact with an adjacent surface leading to the risk of damage if the door is released at an open position in which it is not positively held. For example, the door may open beyond the position at which it is released due to the momentum of the force applied to open the door and/or by a gust of wind if the door is released when stationary.

[0008] The number of intermediate hold open positions may be increased by providing more recesses but the size and spacing of the recesses restrict the angular spacing of the hold open positions that can be achieved. In general, an angular spacing of 15-20° is the minimum that can be obtained with this type of device.

[0009] The present invention has been made from a consideration of the disadvantages aforementioned.

[0010] In particular, the present invention seeks to provide a control system for a closure such as a door and in particular, but not exclusively a vehicle door, which enables a wider range of hold open positions to be achieved than permitted by existing door checks.

[0011] More especially, it is a preferred object of the invention to provide a control system which allows relatively small adjustments to be made to the hold open position of the closure.

[0012] Thus, the invention may permit the angular position of the closure to be adjusted by a few degrees and the closure to be held in selected open positions.

[0013] In this way, the hold open position of the closure can be finely adjusted between closed and fully open according to the space available. As a result, the opening movement of the closure can be adapted to the requirements for a particular situation.

[0014] According to one aspect of the present invention there is provided a control system for a closure mounted for movement relative to a frame towards and away from a closed position, the control system comprising means for releasably holding the closure in an open position, means for monitoring force applied to the closure and movement of the closure, and means for controlling the holding means in response to the monitoring means.

[0015] By this invention, the control means is operable to release the holding means allowing movement of the closure when the monitoring means detects a pre-determined force applied to the closure, and to apply the holding means preventing movement of the closure when the monitoring means detects the closure is stationary or has slowed to a pre-determined speed.

[0016] In this way, the open position of the closure can be adjusted as desired according to the available space thereby reducing the risk of damage to the closure from contact with an adjacent structure. As a result, the closure can be opened to the extent permitted and held at that position until it is desired to close the closure.

[0017] Preferably, the holding means is arranged to apply a braking force to prevent movement of the closure, and the braking force is released to allow movement of the closure when a pre-determined operating force is applied to the closure.

[0018] The braking force may be applied by any suitable means, for example by using devices employing friction, detents, hydraulics, pneumatics, electro-magnets or ferro-fluidics.

[0019] In a preferred embodiment, opening movement of the closure is controlled by a link arm configured to move through a device operable to apply the braking force to the link arm. The link arm may include an end stop to limit opening movement of the closure.

[0020] Advantageously, the monitoring means includes a device for sensing the force applied to the closure and sending a signal to the control means when the pre-determined force is applied, and a device for sensing movement of the closure and sending a signal to the control means according to whether the closure is stationary or moving.

[0021] Any suitable devices may be employed for this purpose. For example, the force detector may comprise an electronic sensor such as a strain gauge or load cell or a mechanical sensor for detecting movement of an element against a pre-loaded spring. The movement detector may, for example, comprise a proximity sensor or optical or magnetic sensor.

[0022] Preferably, the control means comprises a logic controller responsive to signals from the monitoring means to control actuation of the restraining means to releasably hold the closure in a selected position. The logic controller may be programmable to control the function of the system according to user requirements.

[0023] The restraining means may be operable to hold the closure in both open and closed positions. Alternatively, the restraining means may be operable to hold the closure in open positions only.

[0024] Preferably, latch means is provided for securing the closure closed in place of or in addition to the restraining means. Where the closure is secured closed by the latch means and the restraining means, the latter may be released by actuation of the latch means to open the door, for example by actuation of a latch operating handle. Where the closure is secured closed by the latch means only, the restraining means may be released in the closed position by additional input of a sensor to detect the closure is closed, for example a "door closed" switch.

[0025] Advantageously, the control system includes means for applying a constant braking torque to prevent unrestricted movement of the closure when the restraining means is released. For example a friction device or any other suitable means to control movement of the closure.

[0026] Preferably, the control system includes fail-safe means for over-riding the restraining mean. For example, the control means may be arranged to release the restraining means in the event of a power failure or a fire allowing the closure to be opened.

[0027] The invented control system may be applied to any type of closure but is particularly intended to control movement of doors, especially automotive doors.

[0028] For application to automotive doors mounted for pivotal movement between open and closed positions, the monitoring means is preferably arranged to detect torque loads applied to the door by pushing or pulling and to generate a signal to the control means when the pre-determined torque has been applied for a pre-set time, for example 2 seconds. In this way, accidental release of the restraining mechanism by a gust of wind when the door is open or by a person leaning on the door when closed is prevented.

[0029] Longer or shorter time delays may be employed as appropriate for a particular application and it may be desirable for certain applications to have no delay so that the restraining mechanism is released when the pre-determined torque has been applied.

[0030] According to a second aspect of the invention there is provided a control system for a closure such as a vehicle door, the system comprising restraining means for releasably holding the closure in an open position, sensor means for monitoring at least one parameter representative of a condition of the closure, and logic control means responsive to the sensor means for controlling the restraining means according to the detected condition of the closure.

[0031] The sensor means may be arranged to monitor movement of the closure and the logic control means is responsive to the sensor means to apply the restraining means under pre-set conditions. For example the restraining means may be applied when the closure is stationary or slowing down or speeding up.

[0032] Thus, the restraining means may be actuated to hold the closure when it is not moving or if it is moving slower or faster than pre-set lower and upper limits.

[0033] Alternatively or additionally, the sensor means may be arranged to monitor an operating force applied to the closure such as when pushing or pulling a pivotally mounted closure, and the logic control means is responsive to the sensor means to release the restraining means at a pre-determined operating force. The operating force may be set to prevent accidental or inadvertent release of the restraining means.

[0034] In a preferred arrangement, the sensor means is arranged to monitor both movement of the closure and the operating force applied to the closure with the logic control means being responsive to signals from the sensor means representative of the movement and operating force to apply and release the restraining means respectively for holding the closure in any selected one of a range of open positions.

[0035] By this arrangement, the open position of the closure may be finely adjusted between closed and fully open positions enabling the closure to be held at a series of closely spaced apart positions. For example, angular adjustment of a few degrees, preferably about 5° and more preferably of the order of 1-2°, may be obtained between the hold open positions of the closure.

[0036] By such incremental adjustment of the position of the closure, the opening movement can be adapted to the available space so as to avoid damage to the closure. The incremental adjustment may be reduced so as to provide substantially infinite adjustment of the hold open position of the closure.

[0037] According to a third aspect of the invention, there is provided a control system for a vehicle door comprising means for releasably holding the door open, means for monitoring loads applied to the door and generating a signal when a pre-determined load is applied, and means responsive to the signal for releasing the holding means to allow movement of the door to a new position.

[0038] According to a fourth aspect of the invention there is provided a control system for a vehicle door comprising means for monitoring movement of the door and generating a signal representative thereof, and means responsive to the signal for releasably holding the door when stationary.

[0039] The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:-

Figure 1 shows schematically a door control system embodying the invention;

Figures 2A and 2B are sectional views, at right angles to each other, showing application of the door control system to a restraining mechanism for a vehicle door; and

Figure 3 shows a function logic block diagram for controlling operation of a restraining mechanism for a vehicle door.

[0040] Referring first to Figure 1 of the drawings, there is shown a door 1 mounted for pivotal movement relative to a frame 2 about a vertical axis at one side by a pair of hinges 3,4 between open and closed positions. The door 1 may be of any type but in a preferred application of the invention is a vehicle door.

[0041] The door 1 is pivotal towards and away from the closed position and is releasably held in any desired open position by a restraining mechanism indicated schematically by reference numeral 5.

[0042] The restraining mechanism 5 is operable under the control of a logic controller 6 described in more detail later to apply a restraining torque to hold the door 1 in any selected open position and to release the restraining torque to allow pivotal movement of the door 1 towards or away from the closed position.

[0043] Any system of applying the restraining torque may be employed. For example, a brake device (not shown) mounted within the door cavity co-operable with a link (not shown) pivotally connected at one end to the door frame 2 and arranged to move through the brake device as the door 1 moves towards and away from the closed position.

[0044] In a known manner, the link includes an end stop co-operable with the brake device to limit opening movement of the door 1. In the case of a vehicle door, opening movement would typically be limited to a maximum of 60° but the range of opening movement may be varied according to the application.

[0045] The brake device is operated under the control of the logic controller 6 to apply a braking force to the link to hold the door 1 stationary at the selected open position and to release the braking force to allow the door 1 to move from the selected open position.

[0046] Any brake device could be added for this purpose. For example, friction pads to apply a frictional braking force to the link. Alternatively, co-operating plungers and indents may be provided to hold the door 1 at the selected open position. It will be understood, however, that other methods could be used including but not limited to hydraulics, pneumatics, electro magnets and ferro-fluidics.

[0047] Furthermore, whilst the restraining mechanism has been described in the form of a brake device and co-operating link, it will be appreciated that the restraining mechanism could be incorporated in one or both hinges 3,4 or any other arrangement capable of stopping and preventing movement of the door 1.

[0048] The logic controller 6 controls the restraining mechanism 5 to apply and release the braking force to the door 1 in response to a device 7 for monitoring the operating torque applied to the door 1 and a device 8 for monitoring movement of the door 1.

[0049] The device 7 senses the operating torque being applied to the door 1, for example by a pushing or pulling action, and sends a signal to the logic controller 6 when a pre-determined torque is reached. The logic controller 6 in turn is responsive to the signal to cause the restraining mechanism 5 to release the braking force applied to the door 1 allowing the door 1 to move from the position in which it was being held by the restraining mechanism 5.

[0050] The applied torque may be detected by means of electronic sensors such as strain gauges or load cells. Alternatively, the applied torque may be detected by movement of an element against a pre-loaded spring. It will be understood, however, that the actual method employed is not essential and that any system of monitoring the applied torque may be employed.

[0051] The pre-determined torque to release the restraining mechanism 5 may be set at any desired level appropriate to the given application and the device 7 may be arranged to generate the signal only when the pre-determined torque has been applied for a pre-determined time. In this way, inadvertent or accidental release of the restraining mechanism 5 by an instantaneous torque e.g. from a gust of wind, does not release the door 1.

[0052] The device 8 senses movement of the door 1 and sends a signal to the logic controller 6 according to whether the door 1 is moving or stationary. The logic controller 6 in turn is responsive to the signal to cause the restraining mechanism 5 to apply the braking force to the door 1 under pre-set conditions.

[0053] For example, the restraining mechanism may be applied when the door 1 is stationary or slowing down or speeding up. Thus, the restraining mechanism may be applied when the door is moving slower than a pre-determined lower speed or faster than a pre-determined upper speed. In this way, the restraining mechanism is applied if the door slows down to secure the door at the desired position of adjustment, and if the door speeds up to secure the door and prevent uncontrolled movement of the door such as by a gust of wind.

[0054] The movement may be detected by the use of a proximity sensor which detects the presence or absence of teeth on the edge of a wheel so that, as the wheel rotates, the proximity sensor will detect an intermittent signal and, if the wheel is stationary, the proximity sensor will detect a steady signal. Thus, by urging the wheel to rotate as the door 1 moves, the motion of the door 1 is detected. It will be understood, however, that the actual method employed is not essential and that any system of monitoring movement may be employed. For example, systems could be configured with the use of optical or magnetic sensors such as used in automotive anti-lock braking systems. Magnetic zones in a moving element could be used to generate small electrical pulses which in turn could be detected to indicate movement of the door 1.

[0055] As thus far described, the restraining mechanism 5 is operable to prevent movement of the door 1 until a pre-determined operating force is applied and detected by the device 7. The logic controller 6 responds to a signal from the device 7 to cause the restraining mechanism 5 to release the braking force holding the door 1 and allowing the door 1 to be moved from the position in which it was being held to a new position. The movement of the door 1 is detected by the device 8 and the logic controller 6 responds to a signal from the device 8 when it no longer detects movement or the movement is slower or faster than a pre-determined speeds to cause the restraining mechanism 5 to apply the braking force to hold the door 1 at the new position.

[0056] As will now be appreciated, the invented door control system enables the position of the door 1 to be adjusted between the closed and open positions with the door 1 being held in any desired open position. This has particular benefits for application of the system to vehicle doors where the extent to which the door 1 can be opened may vary widely according to the position in which the vehicle is parked. Thus, the door can be opened as far as permitted and held in that position to allow access to and egress from the vehicle until it is desired to close the door without risk of damage by contact with an adjacent vehicle, wall, pillar or other structure obstructing full opening movement of the door.

[0057] Although the invention has been described thus far in its simplest form, it will be understood that the control system can be adapted to the particular needs of any given application by the addition of other features of which some are now described by way of example only.

[0058] For some applications of the system, especially for vehicle doors, it is desirable to control movement of the door when the restraining mechanism 5 is released. This may be achieved by employing a device to apply a constant braking torque to the door 1 which prevents the door 1 moving freely in an uncontrolled manner. Any suitable device may be employed for this purpose. For example, where the restraining mechanism includes a link arm as described previously, a constant braking torque may be provided by a friction pad bearing on the link arm.

[0059] The door may be held in the closed position by the restraining mechanism alone, for example where the control system is applied to internal doors in buildings. For some applications of the system, however, especially for vehicle doors, it is necessary to prevent the door opening accidentally or inadvertently if someone leans against the door. This may be achieved by means of a latch mechanism operable automatically to secure the door when it is moved to the closed position and which is manually releasable by means of an actuator such as a handle. In this arrangement, the restraining mechanism may be released when the door 1 is closed as it is not required to hold the door closed.

[0060] For example, a sensor such as a "door closed" switch may be provided to detect when the door is closed and give a signal to the logic controller to release the restraining mechanism. Alternatively, the restraining mechanism may be applied when the door is closed and released in response to operation of the actuator. Such operation may be effected by incorporating a door operating sensor such as a switch responsive to operation of the actuator in the control loop for the restraining mechanism. The restraining mechanism may be re-applied when the actuator is released. Alternatively, the restraining mechanism may be re-applied in response to the signal from the movement sensor.

[0061] In another arrangement, the restraining mechanism may be released by means of a contact sensor such as a touch sensitive operating pad arranged to sense contact with the door. The restraining mechanism may be re-applied when the contact sensor is released or in response to the signal from the movement sensor. Any suitable contact sensor may be employed with operation by earth leakage, pressure, direct switching or any other appropriate method.

[0062] Referring now to Figures 2A and 2B, there is shown an example of the application of the invented control system to a vehicle door arrester 10 for controlling movement of a vehicle door (not shown) relative to a door frame (not shown).

[0063] The arrester 10 comprises an elongate link arm 11 slidable through a housing 12, and a restraining mechanism 13 located in the housing 12 to hold releasably the link arm 11 and secure the door in selected positions.

[0064] The link arm 11 is the form of a flat bar of rectangular section pivotally connectable at one end to the door frame and having serrations 14 on each side edge face 15. The housing 12 is mountable on the door and the link arm 11 extends through the housing 12 and through a block 16 located in a cavity 17 within the housing 12.

[0065] Mounted in the block 16 is a pressure pad 18 biased by a spring 19 to engage an upper surface 20 of the link arm 11 to apply a constant frictional braking force to sliding movement of the link arm 11 through the housing 12.

[0066] Also mounted in the block 16 is a roller 21 supported for rotation by a spindle 22. The roller 21 contacts a lower surface 23 of the link arm 11 and is rotated by sliding movement of the link arm 11 through the housing 12. The surface of the roller 21 has circumferentially spaced formations such as teeth.

[0067] A proximity sensor 24 is arranged to receive a steady signal when the roller 21 is stationary and an intermittent signal when the roller 21 is rotating. The proximity sensor 24 sends a signal to a logic controller (not shown) according to whether the roller 21 is stationary or rotating to indicate if the link arm 11 is moving or not.

[0068] The restraining mechanism 13 is provided by a pair of blades 25,26 arranged to co-operate with the serrations 14 on the side edge faces 15 of the link arm 11. One of the blades 25 is fixed. The other blade 26 is movable towards and away from the adjacent side edge face 15 under the control of a cam 27 operable by an actuator 28 such as a pneumatic cylinder 29 in response to a signal from the logic controller.

[0069] The restraining mechanism 13 is shown in the locked state in Figure 2B in which the cam 27 is advanced to urge the movable blade 26 towards the link arm 11 so that both blades 25,26 engage respective serrations 14 on the side edge faces 15 to secure the link arm 11.

[0070] In this condition, the block 16 is biased to a centre position within the cavity 17 by a pair of springs 30,31 as shown in Figure 2A. If a force is applied to the door in the direction of sliding movement of the link arm 11 to open or close the door as indicated by the arrows in Figure 2A with the link arm 11 held by the restraining mechanism 13, the block 16 will move in the direction of the applied force against the biasing of the spring resisting such movement. When the applied force is sufficient to displace the block 16 a pre-determined amount from the centre position, such movement is detected by a sensor 32 which sends a signal to the logic controller to retract the cam 27 releasing the restraining mechanism 13 and allowing the link arm 11 to slide through the housing 12 to adjust the position of the door.

[0071] The roller 21 rotates in response to such movement and, when the link arm 11 stops or the speed of movement falls below a lower limit or exceeds an upper limit, the sensor 24 sends a signal to the logic controller to re-apply the restraining mechanism 13 to secure the link arm 11.

[0072] As will be appreciated, the co-operation of the blades 25,26 with the serrations 14 enables fine adjustment to be made to the position in which the link arm 11 is secured. In this way, small changes in the angular position of the door can be made providing substantially infinite adjustment to the open position of the door. As a result, the extent of opening movement of the door can be adjusted according to the available space for a given condition thereby reducing the risk of damage to the door from accidental contact with an adjacent structure.

[0073] The restraining mechanism 13 may be applied to hold the door in closed or open positions or in open positions only with a separate latch mechanism for securing the door closed. Where the door is secured closed by a latch mechanism, a sensor may be provided to detect when the door is closed and give a signal to the logic controller to release the restraining means, for example the sensor may be a "door closed" switch.

[0074] The above is one example of the possible application of the invented door control system and it will be understood the invention is not limited to the details thereof.

[0075] Referring now to Figure 3, there is shown a function logic block diagram for controlling operation of the invented door control system and control movement of a vehicle door.

LOGIC INPUTS ARE:-

[0076] Move sensor - This is a pulsed signal, which indicates that the door is moving. This signal might be taken from a sensor detecting the rotation of a toothed roller as described previously.

[0077] Door closed - This is a steady signal, which is present when the door is closed. This might be derived from a switch, in a similar style to a courtesy light switch.

[0078] Load sensor - This is a temporary signal, which indicates that there is an operating load on the door. This may be derived from a touch pad on the door's surface or from a load detection device in the door arrester mechanism as described previously.

LOGIC OUTPUTS ARE:-

[0079] Hold door - This is a 'one-shot' (0.5s) signal, which would operate an actuator. The actuator would engage a door holding mechanism as described previously.

[0080] Loose door - This is a 'one-shot' (0.5s) signal, which would operate the actuator in the opposite direction. The actuator would disengage the door holding mechanism as described previously.

THE FUNCTION OF THE LOGIC IS AS FOLLOWS:-

[0081] The roller stops moving when the door is stationary and this condition is signified when a signal is received from the move sensor for longer than a pre-determined duration, for example 0.3s, in either an "on" or "off" state.

[0082] If either an 'on' signal or an "off" signal is received from the move sensor for longer than 0.3s indicating the door is stationary and, if the door has not been closed for 0.6s, then the hold door signal is generated to engage the door holding mechanism and the door will be held in it's position.

[0083] If a signal is received from the door operating load sensor or if the door is fully closed then the loose door signal is generated to release the door holding mechanism and the door will be released.

[0084] It will be understood that the logic controller may be programmed to provide any desired operating functions to suit the requirement for a given application and all combinations and alternatives are within the scope of the invention.

[0085] The logic controller may also be employed to provide fail-safe operating modes. For example, to allow the restraining mechanism to be over-ridden in the event of a power failure or an emergency. Thus, by linking to a fire detection system, the logic controller could allow the door to open in the event of a fire. Other applications and uses of the invented control system will be apparent to these skilled in the art.

Claims

1. A control system for a closure mounted for movement relative to a frame towards and away from a closed position, the control system comprising restraining means for releasably holding the closure in an open position, means for monitoring force applied to the closure and movement of the closure, and means for controlling the restraining means in response to the monitoring means.

2. A control system as claimed in Claim 1 wherein the restraining means is arranged to apply a braking force to prevent movement of the closure, and the braking force is released to allow movement of the closure when a pre-determined operating force is applied to the closure.

3. A control system as claimed in Claims 2 wherein opening movement of the closure is controlled by a link arm configured to move through a device operable to apply the braking force to the link arm and the link arm preferably includes an end stop to limit opening movement of the closure.

4. A control system as claimed in any one of the preceding claims wherein the monitoring means includes a device such as an electronic or mechanical sensor for sensing the force applied to the closure and sending a signal to the control means when the pre-determined force is applied, and a device such as a proximity or optical or magnetic sensor for sensing movement of the closure and sending a signal to the control means according to whether the closure is stationary or moving.

5. A control system as claimed in any one of the preceding claims wherein the control means comprises a logic controller responsive to signals from the monitoring means to control actuation of the restraining means to releasably hold the closure in a selected position and the logic controller is preferably programmable to control the function of the system.

6. A control system as claimed in any one of the preceding claims wherein the restraining means is operable to hold the closure in both open and closed positions and latch means is optionally provided for securing the closure closed in addition to the restraining means with the restraining means preferably being released by actuation of the latch means.

7. A control system as claimed in any one of Claims 1 to 5 wherein the restraining means is operable to hold the closure in open positions only and latch means is provided for securing the closure closed with the restraining means preferably being released in the closed position by additional input of a sensor such as a "door closed" switch to detect the closure is closed.

8. A control system as claimed in any one of the preceding claims wherein the control system includes means such as a friction device for applying a constant braking torque to prevent unrestricted movement of the closure when the restraining means is released.

9. A control system as claimed in any one of the preceding claims wherein the control system includes a fail safe means for overriding the restraining means, for example in the event of a power failure or a fire, allowing the closure to be opened.

10. A control system as claimed in any one of the preceding claims wherein the closure is a door, such as an automotive door, and the monitoring means is arranged to detect torque loads applied to the door by pushing and pulling and to generate a signal to the control means when the pre-determined torque has been applied, wherein the signal is preferably generated after a pre-set time, for example 2 seconds.

11. A control system for a closure, the system comprising restraining means for releasably holding the closure in an open position, sensor means for monitoring at least one parameter representative of a condition of the closure, and logic control means responsive to the sensor means for controlling the restraining means according to the detected condition of the closure.

12. A control system as claimed in Claim 11 wherein the sensor means is arranged to monitor movement of the closure and the logic control means is responsive to the sensor means to apply the restraining means under pre-set conditions, for example in any one or more of when the closure is stationary, when the closure is slowing down, when the closure is speeding up, when the closure is moving slower than a lower pre-set limit, when the closure is moving faster than an upper pre-set limit.

13. A control system as claimed in Claim 11 or Claim 12 wherein the sensor means is arranged to monitor an operating force applied to the closure and the logic control means is responsive to the sensor means to release the restraining means at a pre-determined operating force, and the operating force is preferably set to prevent accidental or inadvertent release of the restraining means.

14. A control system for as claimed in Claim 13 wherein the sensor means is arranged to monitor both movement of the closure and the operating force applied to the closure with the logic control means being responsive to signals from the sensor means representative of the movement and operating force to apply and release the restraining means respectively for holding the closure in any selected one of a range of open positions, wherein the open positions may be spaced apart, for example by about 5° or more preferably by about 1-2°, or the open positions may provide substantially continuous adjustment of the hold open position.

15. A control system for a vehicle door comprising means for releasably holding the door open, means for monitoring loads applied to the door and generating a signal when a pre-determined load is applied, and means responsive to the signal for releasing the holding means to allow movement of the door to a new position.

16. A control system for a vehicle door comprising means for monitoring movement of the door and generating a signal representative thereof, and means responsive to the signal for releasably holding the door when stationary.

17. A vehicle having a door fitted with a control system according to any of the preceding claims.

Drawing