WO2017194964A2

WO2017194964A2 - System for drawing a wheeled passenger support into a vehicle

Info

Publication number: WO2017194964A2
Application number: PCT/GB2017/051335
Authority: WO
Inventors: Bryce GREENWOOD
Original assignee: Lateral Design Limited
Priority date: 2016-05-13
Filing date: 2017-05-12
Publication date: 2017-11-16
Also published as: WO2017194964A3; GB201608406D0; GB2551309A

Abstract

There is disclosed a system (18) for drawing a wheeled passenger support (16) into a vehicle (10) and selectively restraining the passenger support against movement. The wheeled passenger support may take the form of a wheelchair, wheeled bed or stretcher. One disclosed system comprises: first and second winches (24a/b), each winch comprising a spool (28a/b), a flexible elongate winch element (30a/b) which can be wound on to the spool and which is adapted to be coupled to the passenger support, and a motor (32a/b) for driving the spool to reel in the winch element; and a control system (34a/b) for controlling operation of the first and second winches. The first and second winches are adapted to be mounted within the vehicle and are operable to draw the passenger support into the vehicle, via the flexible elongate winch elements. The control system comprises a first sensor (36a/b) for monitoring rotation of the first winch spool, a second sensor (38a/b) for monitoring rotation of the second winch spool, and a controller (40a/b) which is arranged so that it can operate the first and second winch motors independently, based on information relating to rotation of the first and second winch spools provided by the first and second sensors, to maintain a substantially even pull on the passenger support during draw-in.

Description

SYSTEM FOR DRAWING A WHEELED PASSENGER SUPPORT INTO A

VEHICLE

The present invention relates to a system for drawing a wheeled passenger support into a vehicle and selectively restraining the passenger support against movement. In particular, but not exclusively, the present invention relates to a system for drawing a wheeled passenger support such as a wheelchair, wheeled bed or stretcher, into a vehicle and selectively restraining the support against movement. It is common practice in modern vehicle design to modify standard road-going vehicles to include equipment which provides access for a wheeled passenger support, such as a wheelchair, or a wheeled bed/stretcher, into the vehicle. Typically, the modification process involves installing a lowered floor, and an inclined ramp along which the passenger support can travel to access the vehicle. The ramp is usually either powered and retractable into the body of the vehicle, or provided as a separate component which can be stored in the vehicle and manually deployed when required.

Manually manoeuvring a passenger support and its occupant along the ramp and into the vehicle can be challenging. Accordingly, a number of different types of powered systems have been developed, for drawing the passenger support into the vehicle with minimal attendant assistance.

One such system comprises a winch having a cable which is coupled to the passenger support, for drawing the support up the ramp and into the vehicle, and a pair of restraining devices known as 'electric reels'. The electric reels are used to restrain the passenger support against movement within the vehicle during transit. Electric reels comprise a reel or spool, a strap (of the type found in vehicle seatbelt assemblies) wound on to the spool, a sprung retracting mechanism for the strap, and an electrically-operated lock. The electric reels are usually positioned at spaced locations within the vehicle, with the winch at a central position between the electric reels. Most systems of this type are rear-loading, in which the passenger support is drawn-in through a rear door of the vehicle. In this situation, the winch is usually positioned on or near the centre-line of the vehicle, with the electric reels disposed laterally either side of the winch, at equidistant spacings.

When it is desired to draw the passenger support into the vehicle, the winch cable and the electric reel straps are paid out and coupled to the passenger support. At this time, the electric reel locks are deactivated. The winch is then activated, drawing the passenger support up the ramp and into the vehicle interior. During this movement, the retracting mechanisms of the electric reels automatically reel the straps back on to their spools, maintaining tension in the straps. When the passenger support has been located at a desired position within the vehicle, the electric reel locks are actuated. This restricts payout of the straps from the spools, exerting restraining forces on the passenger support, to resist movement during transit. The electric reels are activated/energised to pay out the strap. The electric reels are deactivated/de-energised whilst the winch pulls the wheelchair into the vehicle, so that they will not pay the strap out. This is to make sure that, if the winch fails or the assistant slips, the wheelchair will be securely held.

A simplified version of the system described above dispenses with the winch, and includes a pair of modified electric reels. The modified electric reels incorporate a motor, which drives the spool to reel in the strap. In this way, the electric reel straps can be used to draw the passenger support into the vehicle. Following draw-in, the electric reels perform their conventional function of restraining the passenger support against movement during transit.

A significant problem that can be experienced with simplified systems of this type is that the electric reel spools are driven separately, by their respective motors. This can result in an uneven pull on the passenger support, if the motors reel in their respective straps at different rates. This causes the passenger support to twist, making it difficult to manoeuvre it into the vehicle. It can also make it difficult to wind the straps back on to the reels, as the straps can bunch or ride up on an end plate of the spool. In extreme situations, the passenger support can become jammed against internal parts of the vehicle. Even if draw- in can be completed, it is undesirable for the passenger support to be in a twisted position in the vehicle, as this can result in uneven restraining loads being imparted on the support, putting the passenger at risk of injury in the event of a sudden deceleration of the vehicle.

Similar problems can occur if the passenger support is positioned slightly off-centre, relative to the electric reels. In particular, a passenger support that is positioned off-centre is effectively further away from one of the electric reels than the other, so that a greater length of strap is paid out from the reel that is further away. As a consequence, when the motors are activated to reel in the straps, an uneven pull is exerted on the passenger support, causing it to twist.

It is amongst the objects of the present invention to obviate or mitigate at least one of the foregoing disadvantages.

According to a first aspect of the present invention, there is provided a system for drawing a wheeled passenger support into a vehicle and selectively restraining the passenger support against movement, the system comprising:

first and second winches, each winch comprising a spool, a flexible elongate winch element which can be wound on to the spool and which is adapted to be coupled to the passenger support, and a motor for driving the spool to reel in the winch element; and a control system for controlling operation of the first and second winches;

in which the first and second winches are adapted to be mounted within the vehicle and are operable to draw the passenger support into the vehicle, via the flexible elongate winch elements;

and in which the control system comprises a first sensor for monitoring rotation of the first winch spool, a second sensor for monitoring rotation of the second winch spool, and a controller which is arranged so that it can operate the first and second winch motors independently, based on information relating to rotation of the first and second winch spools provided by the first and second sensors, to maintain a substantially even pull on the passenger support during draw-in. Typically, the vehicle will be of a type which has been modified to provide access for the wheeled passenger support into the vehicle, for example by installing a lowered floor, and an inclined ramp along which the passenger support can travel to access the vehicle. The ability to operate the first and second winch motors independently, based on information relating to rotation of the first and second winch spools provided by the first and second sensors, may mitigate at least some of the problems which have been experienced with prior systems discussed above. In particular, in prior systems incorporating modified electric-reels, it was found that an uneven pull can be exerted on the passenger support, in a situation where the motors reeled in the straps at different rates, resulting in twisting of the support. In addition, it was not possible to account for off-centre location of the passenger support. In the system of the present invention, an uneven pull can be restricted, and potentially avoided, by monitoring rotation of the winch spools and independently operating the winch motors. This may also account for the passenger support being positioned off-centre.

Specifically, in the event that one winch motor is found to be rotating its winch spool at a faster rate than the motor of the other winch - a situation which could lead to an uneven pull on the passenger support - such is detected by the controller, based on the information provided by the first and second sensors. This can be corrected by appropriate control of the winch motors. For example, the winch motor which has been rotating its spool at a higher speed may be briefly paused. An off-centre positioning of the passenger support can be detected by the controller, as a greater length of winch element is paid out from one of the spools during coupling to the passenger support. This is recognised by the controller because the spool from which the greater length of winch element is paid out will be rotated further than the spool of the other winch. This can be accounted for by the controller during draw-in, by appropriate control of rotation of the winch spools, to avoid twisting of the passenger support. The first and second sensors may be arranged to monitor rotation of the winch spools themselves, and so directly. The first and second sensors may be arranged to monitor rotation of a part or parts of the spools. The first and second sensors may be arranged to monitor rotation of drive assemblies for the respective spools. The first and second sensors may be arranged to monitor rotation of a drive shaft for or associated with the respective spool. The shaft may be a shaft of the motor and may be a motor output shaft. The shaft may be a drive shaft of or coupled to the spool.

The first and second sensors may be arranged to monitor one or more parameter, which may be selected from the group comprising: a number of revolutions (or part-revolutions as appropriate) performed by the respective winch spools; and a rate of rotation of the respective winch spools. The first and second sensors may be arranged to output data relating to the one or more parameter to the controller. The controller may be arranged to process the data, to determine any adjustment to a number of revolutions (or part revolutions) to be performed by at least one of the winch spools, and/or a rate of rotation of at least one of the winch spools, that is required to maintain the substantially even pull. The controller may comprise a processor for processing the data. The controller may be arranged to vary a number of revolutions (or part-revolutions) performed by a selected one of the winch spools by stopping rotation of said winch spool whilst allowing the other to continue to rotate. The controller may be arranged to vary a rate of rotation of a selected one of the winch spools by stopping rotation of said winch spool, or by restricting the power supplied to said winch. The winch may be electrically powered, in which case power restriction may involve restricting electrical power supply to the winch.

The first and second sensors may be arranged to detect at least one indicator element associated with the respective spool. Detection of the at least one indicator element may provide an indication of a number of revolutions (or part-revolutions as appropriate) performed by the respective winch spools, and/or a rate of rotation of the respective winch spools. The at least one indicator element may be provided integrally with the spool. The at least one indicator element may be provided as a separate component. The at least one indicator element may be coupled to the spool. The at least one indicator element may be mounted on, or may form part of, a drive shaft for or associated with the spool. The at least one indicator element may be a plate, suitably in the form of a ring, mounted on the drive shaft. The at least one indicator may be part of a gear or gear component, which may be coupled to or defined by a shaft of the motor.

The control system may comprise an encoder associated with each motor. The encoder may be an internal encoder of the motor and/or may be provided integrally with the motor. The encoder may be a rotary encoder. Each encoder may comprise the sensor and the indicator element.

The winch spools may each comprise end plates, and an end plate of each winch spool may comprise the at least one indicator element. The end plate may be circular, and the at least one indicator element may be provided at or substantially adjacent to a radial edge of the end plate. There may be a plurality of indicator elements, which may be arranged at spaced locations around a circumference of the end plate. The indicator elements may take the form of castellations or teeth.

The first and second sensors may be Hall effect sensors. The at least indicator element may be a magnetic indicator element. The Hall effect sensors may be arranged to output a voltage signal in response to detection of the magnetic indicator elements. The Hall effect sensors may comprise circuitry which is arranged so that the sensors act as Hall switches, arranged to output a digital signal on detection of the at least one magnetic indicator element. The Hall switches may be arranged to output a digital On' signal on detection of the presence of the at least one magnetic indicator element. The Hall switches may be arranged to output a digital 'off signal when the presence of the at least one magnetic indicator element is not detected.

Where the first and second sensors are Hall effect sensors, and the at least one indicator element is a magnetic indicator element, the sensors may comprise a slot or channel and may be arranged relative to the spool end plates so that the at least one magnetic indicator element passes through said slot. The Hall sensors may be arranged to output a signal on detection of the magnetic indicator element within said slot. Where the winch spools comprise end plates, the end plates may be magnetic and may define the at least one magnetic indicator element. The end plates may be non-magnetic, and the at least one magnetic indicator element may be coupled to the end plate.

The system may comprise a pivoting mounting for the first winch. The system may comprise a pivoting mounting for the second winch. The winch or winches may be pivotally mountable to the vehicle via the pivoting mounting. The pivoting mounting may permit pivoting of the winch about an axis which is substantially vertical and/or which is substantially perpendicular (in use) to a floor of the vehicle. The pivoting mounting may facilitate reeling-in of the flexible elongate winch elements in a situation where the passenger support is positioned off-centre relative to the winches, by allowing pivoting of the winch or winches about said axis/axes. The first and/or second winch may comprise a mounting member for the winch spool, which may be a mounting frame, the spool being rotatably mounted to the mounting member, the pivoting mounting being coupled to the mounting member so that the mounting member can pivot relative to the vehicle.

The system may be arranged to selectively restrain the passenger support against movement relative to the vehicle.

The system, in particular the first and second winches, may comprise locking arrangements for selectively locking or securing the winch spools against rotation. The locking arrangements may prevent pay-out of the flexible elongate winch elements from the spools and so restrain the passenger support. The locking arrangements may prevent pay-in or draw-in of the flexible elongate winch elements on to the spools. The locking arrangements may comprise at least one locking element for locking the winch spools. The at least one locking element may have a fail-safe state, in which it is urged towards a locked position, The locking element may be electrically actuated, and may be solenoid actuated.

The locking arrangements may be selectively operable or activatable to secure the winch spool against rotation. The locking arrangements may be movable between: a release configuration in which rotation of the spool is permitted; and a locking configuration in which rotation of the spool is restricted.

The locking arrangements may comprise a ratchet, and at least one pawl which is operable to engage the ratchet and thereby secure the winch against rotation. The at least one pawl may be movable between: a release position in which the pawl is disengaged from the ratchet, permitting rotation of the spool; and a locking position in which the at least one pawl is engaged with the ratchet, restricting rotation of the spool. In the release

configuration of the locking arrangement, the at least one pawl may be in its release position. In the locking configuration of the locking arrangement, the at least one pawl may be in its locking position. The at least one pawl may be biased towards its release position.

The ratchet may be a ratchet ring, which may be generally annular. The ratchet may comprise a plurality of ratchet teeth, which may be on a radially inner surface of the ratchet ring. Said pawl may comprise at least one tooth for engaging the ratchet teeth.

The locking arrangements may comprise a mounting member for the at least one pawl, which may be a mounting disc, wheel, plate or ring. The mounting member may be coupled to the motor, and may be mounted on a shaft of the motor. The mounting member may be rotatably mounted on the motor shaft. The locking arrangement may be arranged to rotate the mounting member with the motor when the locking arrangement is in the release configuration. The locking arrangement may be arranged so that the mounting member is secured against rotation when the locking arrangement is in the locking configuration. The locking arrangement may comprise a locking element for selectively securing the mounting member against rotation in at least one direction. The at least one direction may be a direction which corresponds to paying-out of the flexible elongate winch element on the spool. Rotation in both directions may be restricted, and so also in a direction which corresponds to drawing-in or paying-in of the flexible elongate winch element.

The locking element may be movable between a release position where it permits rotation of the mounting member, and a locking position where it restricts rotation of the mounting member. The mounting member may comprise a plurality of locking teeth, and the locking element may be arranged to engage teeth of the mounting member to restrict rotation of the mounting member. The locking element may be a locking arm or finger, which may carry one or more teeth for engaging teeth of the mounting ring. The locking element may be pivotally movable between its positions. The locking element may be urged or biased (e.g. under the action of gravity) towards the locking position. The locking element may be moved towards the release position by an actuator, which may be a solenoid operated actuator.

The locking arrangement may comprise an activation element for operating the ratchet assembly. The activation element may be coupled to the motor, and may be mounted on a shaft of the motor. The activation element may be mounted on the motor shaft so that it rotates with the motor shaft. The activation element may be a bobbin. The activation element may serve for moving the ratchet assembly between the release and locking configurations. The activation element may serve for moving the at least one pawl between the release and locking positions. The activation element may comprise a cam surface which cooperates with a corresponding cam surface on the at least one pawl, for urging the pawl to the locking position. The activation element may urge the at least one pawl to the locking position only when the pawl mounting member is restrained against rotation. The activation element may be rotatable relative to the pawl mounting member when the pawl mounting member is restrained against rotation, to bring the activation element into contact with the at least one pawl. This may serve to impart a force on the at least one pawl to urge it to its locking position. Rotation of the activation element in a first rotational direction may move the at least one pawl to the locking configuration. Rotation of the activation element in a second, opposite rotational direction may move the at least one pawl to the release configuration.

Reference is made in this document to a wheeled passenger support. The wheeled passenger support may be of any suitable type, including but not limited to: a wheelchair; a wheeled bed; a wheeled stretcher; a mobility vehicle; and a child's buggy, pram or pushchair.

The system may have a use both in the drawing-in of a passenger support and so loading of the support into the vehicle, and for controlling movement of the passenger support during unloading from the vehicle. During unloading, the winches may be operable to impart a restraining load on the passenger support, to control movement of the support. The flexible elongate elements may be paid-out from the spools during unloading. The winches may be operable to arrest movement of the passenger support.

The flexible elongate winch elements may be selected from the group comprising: a strap; a tie; a cable; a chain; and a combination of two or more thereof. The elongate winch elements may be webbings or of a webbing material, in particular a safety belt webbing material.

The system may comprise a remote control, for controlling operation of at least one of the winch and the locking assembly, from a remote location. The remote location may be external of the vehicle. The system may be an assisted system, which may require an attendant or assistant for aiding and/or controlling loading and unloading of the passenger support into and out of the vehicle.

The winches may be electrically operated winches, and the system may comprise limiters which limit driving power of the motors, for example in the event of the passenger support becoming obstructed, particularly during drawing-in to the vehicle. This may serve to restrict injury to a passenger. The limiter may be arranged to limit the current that can be drawn by the winch motors.

The system may comprise a further winch and associated sensor, the controller arranged to operate a motor of said winch based on information relating to rotation of a spool of the winch, to maintain the substantially even pull.

According to a second aspect of the present invention, there is provided a vehicle comprising a system for drawing a wheeled passenger support into the vehicle and selectively restraining the passenger support against movement according to the first aspect of the invention.

Further features of the system forming part of the vehicle of the second aspect of the invention may be derived from the text set out above relating to the first aspect of the invention.

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a vehicle of a type which has been modified to provide access for a wheeled passenger support;

Fig. 2 is a side view of the vehicle of Fig. 1 , incorporating a system for drawing a wheeled passenger support into the vehicle and selectively restraining the passenger support against movement, in accordance with an embodiment of the present invention, the vehicle being shown in partial longitudinal cross-section;

Fig. 3 is a perspective view of the system shown in Fig. 2, taken from above and shown in use, during the drawing-in of a wheeled passenger support on to a test rig representing part of a vehicle of the type shown in Fig. 1 ; Figs. 4, 5, 6 and 7 are enlarged side, front, plan and perspective views, respectively, of a winch, which can form part of the system shown in Figs. 2 and 3;

Figs. 8, 9 and 10 are enlarged perspective, front and side views, respectively, of an alternative winch, which can form part of the system shown in Figs. 2 and 3;

Fig. 1 1 is a cross-sectional side view of the winch shown in Fig. 8, taken about the line A- A in Fig. 9. Turning firstly to Fig. 1 , there is shown a perspective view of a vehicle, indicated generally by reference numeral 10, of a type which has been modified to provide access for a wheeled passenger support. The wheeled passenger support can include, but is not restricted to, a wheelchair, a wheeled bed or stretcher, a mobility vehicle, or a child's buggy, pram or pushchair. The vehicle 10 has been modified to include a specially lowered floor portion 12, and includes a hinged ramp 14 which can be folded-up and stored in the vehicle 10 when not required. The ramp can be powered or may be manually deployable. A wheeled passenger support can pass along the ramp 14 and on to the lowered floor 12, and so enter and exit the vehicle 10. Fig. 2 is a side view of the vehicle 10, incorporating a system for drawing a wheeled passenger 16 support into the vehicle and selectively restraining the passenger support against movement, in accordance with an embodiment of the present invention, the system indicated generally by reference numeral 18. In the illustrated embodiment, the passenger support 16 takes the form of a wheelchair. It will be understood that the invention encompasses a vehicle 10 comprising the system 18. The vehicle 10 is shown in partial longitudinal cross-section in the drawing, illustrating an internal part of a rear section 20 of the vehicle.

The system 18 is also shown in the perspective view of Fig. 3, taken from above and shown in use, during the drawing-in of a wheeled passenger support on to a test rig 22 representing part of the vehicle 10 shown in Figs. 1 and 2. The test rig 22 comprises a simulated lowered vehicle floor portion 12, and illustrates the system 18 during an operation to draw-in the wheelchair 16.

The system 18 comprises first and second winches 24a and 24b, which are shown in more detail in the enlarged side, front, plan and perspective views of Figs. 4, 5, 6 and 7, respectively. The winches 24a and 24b are of like construction and operation, and so only a single winch is shown in Figs. 4 to 7. Like components of the winches 24a and 24b share the same references numerals, with the appropriate suffix. The winches 24a, 24b each comprise a spool (or reel) 28, a flexible elongate winch element 30 which can be wound on to the spool 28 and which is adapted to be coupled to the wheelchair 16, and a motor 32 for driving the spool 28 to reel in the winch element 30. The system also comprises a control system, indicated generally by reference numeral 34, for controlling operation of the first and second winches 24 and 26.

The flexible elongate winch elements 30a, 30b are typically straps, and in particular are straps formed of a webbing material, such as a safety belt webbing material. Materials of this type provide a degree of extensibility under load, reducing shock loads on a passenger in the wheelchair 16 in the event of a sudden deceleration of the vehicle 10. The straps 30a, 30b carry suitable fixings (not shown) for securing the straps to the wheelchair. The fixings may take the form of a seatbelt buckle provided at a position spaced a short distance from an end of the strap, and a latch member on the strap end which can be looped around a frame of the wheelchair and secured to the buckle. The first and second winches 24 and 26 are mounted within the vehicle 10, suitably at a location above the lowered floor 12, and are operable to draw the wheelchair 16 into the vehicle 10, via the straps 30. The control system 34 comprises a first sensor 36a for monitoring rotation of the first winch spool 28a, a second sensor 36b for monitoring rotation of the second winch spool 28b, and a controller 40 which is arranged so that it can operate the first and second winch motors 32a and 32b independently, based on information relating to rotation of the first and second winch spools 28a and 28b provided by the first and second sensors 36a and 36b. In this way, it is possible to maintain a substantially even pull on the wheelchair 16 during draw-in to the vehicle 10, using the system 18.

The ability to operate the first and second winch motors 32a and 32b independently, based on information relating to rotation of the first and second winch spools 28a and 28b provided by the first and second sensors 36a and 36b, may mitigate at least some of the problems which have been experienced with prior systems discussed above.

In particular, in prior systems incorporating modified electric-reels, it was found that an uneven pull can be exerted on a wheelchair, in a situation where the motors reeled in the straps at different rates, resulting in twisting. In addition, it was not possible to account for off-centre location of a wheelchair. In the system 18 of the present invention, an uneven pull can be restricted, and potentially avoided, by monitoring rotation of the winch spools 28a and 28b, and independently operating the winch motors 32a and 32b. This may also account for the wheelchair 16 being positioned off-centre.

Specifically, in the event that one of the winch motors 32a or 32b is found to be rotating its winch spool 28a or 28b at a faster rate than the motor of the other winch, such is detected by the controller 40, based on the information provided by the first and second sensors 36a and 36b. This can be corrected by appropriate control of the winch motors 32a and 32b. For example, the winch motor which has been rotating its spool at a higher speed may be briefly paused.

An off-centre positioning of the passenger support may also be detectable by the controller 40, as a greater length of flexible winch element 30a, 30b is paid out from one of the spools 28a, 28b during coupling to the wheelchair 16. This is recognised by the controller 40 because the spool 28a, 28b from which the greater length of winch element 30a, 30b is paid out will be rotated further than the spool of the other winch during unreeling from the spool. This can be accounted for by the controller 40 during draw-in, by appropriate control of rotation of the winch spools 28a and 28b, to avoid twisting of the wheelchair 16. Whilst the system 18 has been described primarily in relation to the drawing-in of the wheelchair 16 into the vehicle 10, the system 18 can also serve for controlling movement of the wheelchair 16 during unloading from the vehicle 10. Accordingly, the system 18 has a use both in the drawing-in of the wheelchair 16 and so loading of the wheelchair into the vehicle 10, and for controlling movement of the wheelchair 16 during unloading from the vehicle 10. In particular, the system 18 is operable to control descent of the wheelchair 16 down the ramp 14, and can control operation of the winches 28a, 28b to ensure substantially even passage of the wheelchair 16 without twisting. The system 18, and its method of operation, will now be described in more detail.

The first and second sensors 36a and 36b are arranged to monitor one or more parameter, which may be a number of revolutions (or part-revolutions as appropriate) performed by the respective winch spool 28a or 28b, and/or a rate of rotation of the respective winch spool. The first and second sensors 36a and 36b are arranged to monitor rotation of the respective winch spools 28a and 28b themselves, and so directly. In particular, and as will be described below, the first and second sensors 36a/b are arranged to monitor rotation of part of the respective spools 28a/b. The sensors 36a and 36b are arranged to output data relating to the measured parameter(s) to the controller 40. The controller 40 is arranged to process the data, suitably via an appropriate built-in processor (not shown), to determine any adjustment to a number of revolutions (or part revolutions) to be performed by a selected one of the winch spools 28a or 28b, and/or a rate of rotation one of the winch spools, so as to maintain a substantially even pull.

The controller 40 can vary a number of revolutions (or part-revolutions) performed by the selected winch spool 28a or 28b by stopping rotation of the selected spool whilst allowing the other to continue to rotate. Additionally or alternatively, the controller can vary a rate of rotation of a selected one of the winch spools 28a or 28b, by stopping rotation of the selected spool, or by restricting the power supplied to the winch 32a, 32b associated with the spool. The winches 32a, 32b will typically be electrically powered, via a suitable battery 42, power restriction thus involving restricting the supply of electrical power to the appropriate winch.

To facilitate determination of a number of revolutions (or part-revolutions) performed by the winch spools 28a and 28b, and/or a rate of rotation of the spools, the system 18 comprises at least one indicator element 44a, 44b associated with each spool 28a, 28b. In the illustrated embodiment, the spools 28a, 28b comprise a plurality of respective indicator elements 44a, 44b. The first and second sensors 36a, 36b are arranged to detect the respective indicator elements 44a, 44b, detection of the indicator elements providing an indication of a number of revolutions (or part-revolutions as appropriate) performed by the respective winch spool 28a, 28b and/or a rate of rotation of the respective spool.

Specifically, the number of indicator elements 44a, 44b and their positions on the spools 28a, 28b is known. Consequently, the number of revolutions or part revolutions performed by the winch spools 28a, 28b can be determined by 'counting' the number of indicator elements detected by the sensors 36a, 36b during reeling-in (or indeed paying-out) of the flexible elongate straps 30a, 30b.

In the illustrated embodiment, the winch spools 28a, 28b comprise respective hubs 45a, 45b and spaced end plates 46a, 48a and 46b, 48b. The indicator elements 44a and 44b are provided on the end plates 46a and 46b nearest the motors 32a and 32b. As can be seen from the drawing, the end plates 46a and 46b are circular, and the indicator elements 44a, 44b are provided a radial edge of the plate. The indicator elements 44a, 44b are arranged at spaced locations around a circumference of the end plates 46a, 46b, and optionally take the form of castellations or teeth.

In the illustrated embodiment, the first and second sensors 36a and 36b are Hall effect sensors, and the castellations 44a and 44b are magnetic. This can suitably be achieved by constructing the spool end plates 46a and 46b of a magnetic material. Alternatively, the magnetic indicator elements 44a, 44b can be provided as separate components, coupled to the end plates 46a and 46b, which will then be non-magnetic. The sensors 36a and 36b are arranged to output a voltage signal to the controller 40 in response to detection of the castellations 44a and 44b. The sensors 36a and 36b comprise suitable circuitry (not shown) which is arranged so that the sensors act as Hall switches, outputting a digital signal on detection of the castellations 44a, 44b. The switches 36a, 36b output a digital 'on' signal on detection of the presence of castellations 44a, 44b, and a digital Off signal when the presence of castellations is not detected. Accordingly, a number of revolutions (or part-revolutions) performed by the winch spools 28a and 28b, and/or a rate of rotation of the spools, can be determined by counting the number of On' signals (which may be referred to as 'clicks') supplied by the switches 36a, 36b to the controller 40. As best shown in Fig. 5, the Hall switches 36a, 36b comprise slots or channels 50a, 50b which are arranged relative to the spool end plates 46a, 46b so that the castellations 44a, 44b pass through the slots. The Hall sensors 36a, 36b are thus arranged to output a signal on detection of a castellation 44a, 44b within the slot 50a, 50b. The system 18 also comprises pivoting mountings for the first and second winches 24a, 24b, the mountings shown schematically in Fig. 5 and given the reference numeral 52a, 52b. The pivoting mountings 52a, 52b are single point mountings which serve for pivotally mounting the winches 24a, 24b to the vehicle 10. The mountings 52a, 52b permit pivoting of the winches 24a, 24b about axes 53a, 53b which are substantially vertical and/or which are substantially perpendicular (in use) to the floor 12 of the vehicle 10.

Any mounting which facilitates pivoting of the winches 24a, 24b relative to the vehicle 10 may be employed. Indeed, the skilled person will be aware of alternatives to the mountings disclosed herein. In the illustrated embodiment, the pivoting mountings 52a, 52b comprise threaded bolts 54a, 54b which pass through bores 56a, 56b in mounting frames 58a, 58b of the winches 24a, 24b. The bolts 54a, 54b are secured to the vehicle 10, such as via a corresponding nut, or by engagement in a threaded bore (not shown), and effectively clamp the mounting frames 58a, 58b to the vehicle. Upper and lower washers 60a, b and 62a, b may be provided, to facilitate rotation of the frames 58a, 58b relative to the vehicle 10. Suitably, the washers 60a, b and 62a, b are of a low friction material, for example a plastics material such as PTFE. When the wheelchair 16 is drawn-in to the vehicle 10, the flexible elongate straps 30a, 30b are reeled on to their respective spools 28a, 28b. As a result, the angles which the straps 30a, 30b adopt, relative to a centreline 62 of the vehicle 10 (Fig. 3) progressively changes. The pivoting mountings 52a, 52b accommodate such changes by allowing pivoting of the winches 24a, 24b about their axes 53a, 53b. In addition, the pivoting mountings 52a, 52b can accommodate variations in said angle which occur in a situation where the wheelchair 18 is positioned off-centre relative to the winches 28a, 28b.

The winch motors 32a, 32b are coupled to the spools 28a, 28b via worm and wheel gearboxes 60a, 60b, for imparting a drive force on the spool hubs 45a, 45b. The system 18 is operable to restrain the wheelchair 16 against movement during transit within the vehicle 10. This can be achieved by providing locking arrangements (not shown) for locking the winch spools 28a, 28b against rotation, to prevent pay-out of the straps 30a, 30b from the spools and so restrain the wheelchair 16. The locking arrangements can comprise at least one locking element for locking the winch spools, which may have a fail-safe state, in which it is urged towards a locked position. The locking element may be electrically actuated, and may be solenoid actuated. In a variation, locking of the winch spools 28a, 28b can be achieved by securing the motors 32a, 32b against rotation, optionally by locking the gearboxes 60a, 60b against movement.

Turning now to Fig. 8, there is shown a perspective view of an alternative winch, which can form part of the system 18 shown in Figs. 2 and 3, the winch indicated generally by reference numeral 124. It will be understood that the system 18 would include two such winches, given the reference numerals 124a and 124b, respectively. The winches

124a/124b are of similar construction and operation to the winches 24a/24b shown in Figs. 4 to 7 and discussed above. Like components of the winches 124a/ 124b with the winches 24a 24b share the same reference numerals, incremented by 100.

The winches 124a/b are also shown in the front and side views of Figs. 9 and 10, and in the cross-sectional side view of Fig. 1 1, which is taken about the line A-A in Fig. 9. The winches 124a/b differ from the winches 24a/b primarily in terms of locking arrangements 64a b of the winches, best shown in Fig. 1 1, which serve for selectively locking spools 128a/b of the winches against rotation. Inclusion of the locking arrangements 64a/b has the result that a sensor 136a/b for monitoring rotation of the spool 128a/b is associated with an end plate 148a/b of the spool 128a/b, rather than end plates 146a/b closest to a motor 132a/b of the winch. Accordingly, in this embodiment, the end plate 148a/b carries indicator elements 144a/b.

The locking arrangements 64a/b are selectively operable to secure the winch spool 128a/b against rotation. The locking arrangements 64a/b are movable between a release configuration, shown in Fig. 1 1, in which rotation of the spool 128a/b is permitted, and a locking configuration in which rotation of the spool is restricted.

The locking arrangements 64a/b comprise a ratchet assembly 66a/b, including a ratchet 70a/b. The ratchet 70a/b takes the form of an annular ratchet ring comprising a plurality of ratchet teeth 72a/b, which are arranged around a radially inner surface of the ring. The ratchet assembly also comprises at least one pawl 74a/b, which is operable to engage the ratchet ring 70a/b and thereby secure the spool 128a/b against rotation. In the illustrated embodiment, the ratchet assembly 66a/b comprises first pawls 74a/b and second pawls 76a/b. The ratchet ring 70a/b is secured to a mounting frame 158a/b of the winch 124a/b, and so secured against rotation. The pawls 74a/b and 76a/b are movable between release positions (Fig. 1 1) in which they are disengaged from the ratchet ring 70a/b, permitting rotation of the spools 128a/b, and a locking position in which they are engaged with the ratchet ring, restricting rotation of the spools. In the release configuration of the locking arrangement 64a/b, the pawls 74a/b and 76a/b are in their release positions, whilst in the locking configuration of the locking arrangement, the pawls are in their locking positions.

The pawls 74a/b and 76a/b are pivotally mounted to a mounting member 86a/b of the ratchet assembly 66a/b, via mounting pins 82a/b and 84a/b, for movement between their release and locking positions. In the illustrated embodiment, the mounting member 86a/b takes the form of a disc or wheel. The pawls 74a/b and 76a/b comprise respective teeth 78a/b and 80a/b for engaging the ratchet ring 70a/b, in particular ratchet teeth 72a/b of the ratchet ring. The pawls 74a/b and 76a/b are biased towards their release position, and so to the position of Fig. 1 1. Suitably, this can be achieved via torsion springs (not shown), located on the pins 82a/b and 84a/b. The mounting disc 86a/b is freely rotatably mounted on a shaft 87a/b of the motor 132a/b. The mounting disc 86a/b is arranged so that it can rotate with the motor shaft 87a/b (relative to the ratchet ring 70a/b) when the locking arrangement 64a/b is in the release configuration, but is secured against rotation relative to the ratchet ring when the locking arrangement 64a/b is in its locking configuration.

The locking arrangement 64a/b comprises a separate locking element 88a/b for selectively securing the mounting disc 86a/b against rotation. The locking element 88a/b takes the form of a locking arm, which is pivotally mounted to the frame 158a/b so that it can move between a release position where it permits rotation of the mounting disc 86a/b, and a locking position (Fig. 1 1) where it restricts rotation of the mounting disc. The locking element 88a/b must be released from the mounting disc 86a/b, in order to permit rotation of the disc relative to the ratchet ring 70a/b, in at least one rotational direction (which will be described below). The mounting disc 86a/b comprises a plurality of locking teeth, shown in phantom outline at 90a/b in the drawing. The locking arm 88a/b is arranged to engage the teeth 90a/b of the mounting disc 86a/b to restrict rotation of the disc, suitably via one or more tooth, shown in phantom outline at 92a/b, which engages the teeth of the mounting disc. The locking arm 88a/b is urged or biased towards the locking position, suitably under the action of gravity. The locking arm 88a/b is moved to the release position under the action of an actuator which, in the illustrated embodiment, takes the form of a solenoid actuator 94a/b. A rod 96a/b of the solenoid actuator 94a/b engages the locking arm 88a/b to move it from its locked position to its release position. The locking arrangement 64a/b also comprises an activation element 98a/b for operating the locking arrangement. The activation element 98a/b takes the form of a bobbin, and is mounted on the motor shaft 87a/b for rotation together with the shaft. The bobbin 98a/b serves for moving the locking arrangement 64a/b between its release and locking configurations, and in particular for moving the pawls 74a/b and 76a/b between their release and locking positions. The bobbin 98a/b comprises a pair of projections or lobes 65a/b, which define cam surfaces 67a/b that cooperate with corresponding cam surfaces 69a/b on the pawls 74a/b, and cam surfaces 71 a/b on the pawls 76a/b, for urging the pawls to their locking positions.

In use, the winch 124a/b is initially in a rest position, in which the ratchet pawls 74a/b and 76a/b are disengaged from the ratchet rings 70a/b, and the locking arm 88a/b is engaged with the pawl mounting disc 86a/b. In this position, the winch spools 128a/b are 'fail-safe' locked against rotation in the direction of the arrow C (Fig. 1 1), which would pay-out the flexible winch straps (not shown) wound on the spools. This resists movement of the wheelchair 16 away from the winch 124a/b. The shape of the teeth 90a/b on the mounting disc 86a/b, and of the tooth 92a/b on the locking arm 88a/b does, however, allow the winch strap to be paid-in, and so the wheelchair to be drawn closer to the winch 124a/b. Specifically, the angle of the teeth 90a/b and 92a/b is such that rotation of the spool 128a/b in the direction B (to pay in the strap) acts to lift the locking arm 88a/b up, so that the mounting disc 86a/b can rotate around to a position where the tooth 92a/b engages the next-most tooth 90a/b of the disc.

When it is desired to pay-out the winch strap, it is necessary to operate the solenoid actuator 94a/b, to move the locking arm 88a/b to its release position, where the tooth 92a/b is disengaged from the teeth 90a/b of the mounting disc 86a/b. This frees the mounting disc 86a/b for rotation relative to the ratchet ring 70a/b, under the action of the bobbin 98a/b contacting the pawls 74a/b and 76a/b, as shown in Fig. 1 1. This allows the motor shaft 87a/b to rotate the spool 128a/b in the direction C, to pay-out the winch strap. When the winch strap has been paid-out a desired distance, for example for coupling to the wheelchair 16 located outside the vehicle 10, the winches 124a/b are then operated to rotate the spools 128a/b in the direction B, drawing the wheelchair 16 into the vehicle 10. In the event of a power failure to the winches 124a/b at this time, the solenoid actuator 94a/b would be deactivated. A rotation of the spool 128a/b in the direction C would then be prevented. This is because deactivation of the actuator 94a/b releases the locking arm 88a/b, which engages the mounting disc 86a/b, preventing the disc from rotating in the direction C with the motor shaft 87a/b. Specifically, when the mounting disc 86a/b is stationary (held by the locking arm 88a/b), and the spool 128a/b and bobbin 98a/b caused to rotate in direction C (under the load of the passenger transmitted via the straps 30a/b), the pawls 74a/b and 76a/b are forced to engage into the ratchet 70a/b by the cam faces 69a/b and 71a/b. This prevents further rotation of the spool 128a/b in the direction C. This ensures that the wheelchair 16 cannot travel back down the ramp 14 in an uncontrolled manner during a power failure. The locking arm 88a/b may effectively act as a low-load lock to secure the mounting disc 86a/b against rotation, enabling subsequent operation of the pawls 74a/b and 76a/b, which then provide a primary lock which secures the spool 128a/b against paying-out the straps 30a/b, and so prevents movement of the wheelchair 16 down the ramp 14.

When the wheelchair 16 has been drawn-into the vehicle 10 and located in a desired position, the locking arrangements 64a/b are operated to secure the wheelchair against movement away from the winches 124a/b. This is achieved by deactivating the solenoid actuators 94a/b, so that the arms 88a/b engage the mounting disc 86a/b. Rotation of the bobbin 98a/b in the direction C (for example, due to a force imparted on the spools 128a/b by the wheelchair 16) causes the bobbin to urge the pawls 74a/b and 76a/b to their locking positions, where they engage the ratchet ring 70a/b. This is due to contact between the cam surfaces 67a/b on the bobbin 98a/b and the cam surfaces 69a/b and 71 a/b on the pawls 74a/b and 76a/b.

If it is desired to pay the winch straps out following operation of the locking arrangements 64a/b, by rotating the spools 128a/b in the direction C, then it is first necessary to rotate the bobbin 98a/b a small distance in the opposite direction B, so that the pawls 94a/b and 96a/b release from the ratchet ring 70a/b, under the action of the pawl springs. This frees the mounting disc 86a/b for rotation relative to the ratchet ring 70a/b, so that the spool 128a/b can in turn rotate and pay out the winch strap. In variations on the embodiments shown in the drawings and discussed above, the control systems 34a/b and 134a/b may comprise an encoder (not shown) associated with each motor 32a/b, 132a/b, and which may be an internal encoder of the motor. Suitably, the encoder may be a rotary encoder. The sensors and indicator elements may form part of the encoders and/or the motors. Accordingly, first and second encoders/motors may include the respective first and second sensors. The sensors may be arranged to monitor rotation of a drive assembly for the respective spools 28a/b and 128a/b. For example, the first and second sensors may be arranged to monitor rotation of a drive shaft for or associated with the respective spools. In particular, the sensors may be arranged to monitor gear components of or on the shafts, such as parts of a worm gear of the shaft. The shaft may be a shaft of the motor 32a/b, 132a/b and may be a motor output shaft. Alternatively, the shaft may be a drive shaft of or coupled to the spool 28a/b, 128a/b. The indicator elements may be provided separately and coupled to the spools, for example mounted on drive shafts for or associated with the spools. The indicator element may be a plate, suitably in the form of a ring, mounted on the drive shaft. The ring is rotated with the shaft and rotation of the ring monitored by the sensor in the same way as that described above, to facilitate determination of a number of revolutions (or part-revolutions) performed by the winch spools 28a/b and 128a/b, and/or a rate of rotation of the spools.

Various modifications may be made to the foregoing, without departing from the spirit or scope of the present invention.

For example, the system may comprise a remote control, for controlling operation of at least one of the winch and the locking assembly, from a remote location. The remote location may be external of the vehicle.

The system may be an assisted system, which may require an attendant or assistant for aiding and/or controlling loading and unloading of the passenger support into and out of the vehicle. The winches may be electrically operated winches, and the system may comprise limiters which limit driving power of the motors, for example in the event of the passenger support becoming obstructed, particularly during drawing-in to the vehicle. This may serve to restrict injury to a passenger. The limiter may be arranged to limit the current that can be drawn by the winch motors.

Claims

1. A system for drawing a wheeled passenger support into a vehicle and selectively restraining the passenger support against movement, the system comprising:

and in which the control system comprises a first sensor for monitoring rotation of the first winch spool, a second sensor for monitoring rotation of the second winch spool, and a controller which is arranged so that it can operate the first and second winch motors independently, based on information relating to rotation of the first and second winch spools provided by the first and second sensors, to maintain a substantially even pull on the passenger support during draw-in.

2. A system as claimed in claim 1 , in which the first and second sensors are arranged to monitor rotation of parts of the spools.

3. A system as claimed in claim 1 , in which the first and second sensors are arranged to monitor rotation of drive assemblies for the respective spools.

4. A system as claimed in claim 3, in which the first and second sensors are arranged to monitor rotation of a drive shaft associated with the respective spool.

5. A system as claimed in any preceding claim, in which the first and second sensors are arranged to monitor one or more parameter selected from the group comprising: a number of revolutions performed by the respective winch spools; and a rate of rotation of the respective winch spools.

6. A system as claimed in claim 5, in which the first and second sensors are arranged to output data relating to the one or more parameter to the controller.

7. A system as claimed in claim 6, in which the controller is arranged to process the data, to determine any adjustment to a number of revolutions to be performed by at least one of the winch spools that is required to maintain the substantially even pull.

8. A system as claimed in claim 6 or 7, in which the controller is arranged to process the data, to determine any adjustment to a rate of rotation of at least one of the winch spools that is required to maintain the substantially even pull.

9. A system as claimed in any preceding claim, in which the first and second sensors are arranged to detect at least one magnetic indicator element associated with the respective spool.

10. A system as claimed in claim 9, in which the at least one indicator element is provided integrally with the spool.

1 1. A system as claimed in claim 9, in which the at least one indicator element is provided as a separate component.

12. A system as claimed in claim 9, in which the at least one indicator element forms part of a drive shaft associated with the spool.

13. A system as claimed in any one of claims 1 to 9, 1 1 or 12, in which the control system comprises an encoder associated with each motor.

14. A system as claimed in claim 13, in which the encoder is provided integrally with the motor.

15. A system as claimed in either of claims 9 or 10, in which the winch spools each comprise end plates, the end plates comprising the at least one indicator element.

16. A system as claimed in claim 15, in which there are a plurality of indicator elements arranged at spaced locations around a circumference of the end plate.

17. A system as claimed in any one of claims 9, 10, 15 or 16, in which the first and second sensors are Hall effect sensors arranged to output a voltage signal in response to detection of the magnetic indicator elements.

18. A system as claimed in any preceding claim, comprising pivoting mountings for the winches, by which the winches can pivot about substantially vertical axes.

19. A system as claimed in any preceding claim, comprising locking arrangements for selectively locking the winch spools against rotation.

20. A system as claimed in claim 19, in which the locking arrangements each comprise a ratchet and at least one pawl which is operable to engage the ratchet and thereby secure the winch spool against rotation, the at least one pawl being movable between:

a release position in which the pawl is disengaged from the ratchet, permitting rotation of the spool; and

a locking position in which the at least one pawl is engaged with the ratchet, restricting rotation of the spool.

21. A system as claimed in claim 20, in which the locking arrangements each comprise a mounting member for the at least one pawl, the mounting member being coupled to the motor and rotatable with the motor when the locking arrangement is in its release configuration.

22. A system as claimed in any one of claims 19 to 21 , in which the locking arrangements each comprise a locking element for selectively securing the mounting member against rotation in a direction which corresponds to paying-out of the flexible elongate winch element on the spool.

23. A system as claimed in claim 22, in which the locking element is movable between a release position where it permits rotation of the mounting member, and a locking position where it restricts rotation of the mounting member.

24. A system as claimed in claim 23, in which the locking element is moved towards the release position by a solenoid operated actuator.

25. A system as claimed in any one of claims 19 to 24, in which the locking arrangements each comprise an activation element for operating the ratchet assembly, the activation element being mounted on a shaft of the motor so that it rotates with the motor shaft.

26. A system as claimed in claim 25, in which the activation element serves for moving the at least one pawl between the release and locking positions.

27. A system as claimed in claim 26, in which the activation element comprises a cam surface which cooperates with a corresponding cam surface on the at least one pawl, for urging the pawl to the locking position.

28. A system as claimed in claim 27, when dependent upon claim 21, in which the activation element urges the at least one pawl to the locking position only when the pawl mounting member is restrained against rotation.

29. A system as claimed in claim 27 or 28, in which rotation of the activation element in a first rotational direction moves the at least one pawl to the locking configuration, and rotation of the activation element in a second opposite rotational direction moves the at least one pawl to the release configuration.

30. A vehicle comprising a system for drawing a wheeled passenger support into the vehicle and selectively restraining the passenger support against movement according to any one of the preceding claims.