GB2543471A

GB2543471A - Improvements in or relating to control mechanisms for vehicle access ramps

Info

Publication number: GB2543471A
Application number: GB1422011.5A
Authority: GB
Inventors: Thomas Smith Lee; Pearson Simon
Original assignee: SIRUS AUTOMOTIVE Ltd
Current assignee: SIRUS AUTOMOTIVE Ltd
Priority date: 2014-12-11
Filing date: 2014-12-11
Publication date: 2017-04-26

Abstract

A control mechanism 10 for a vehicle access ramp 12 is provided for a vehicle 13. The control mechanism is pivotally mounted to be movable between an upright, stowed position, figure 1a, and a lowered position, figure 1b, providing ramp access to the vehicle from the neighbouring ground when in the lowered position. The control mechanism comprises a spring arrangement 16, a releasable lock arrangement 18 operable to lock the spring arrangement in a charged condition, and a coupling arrangement 20, 24, 26 operable to provide a releasable coupling between the spring arrangement and a vehicle access ramp. The lock arrangement is engageable as the ramp reaches the first intermediate position to lock the spring arrangement in the charged condition. The coupling arrangement is releasable at the intermediate position to allow the ramp to continue moving to the lowered position while the spring arrangement is locked. When the lock arrangement is released with the ramp in the lowered position, the spring arrangement drives the ramp from the lowered position to a second intermediate position. The ramp is movable back from the first intermediate position or the second intermediate position to the stowed position.

Description

Improvements in or relating to control mechanisms for vehicle access ramps

The present invention relates to control mechanisms for vehicle access ramps.

Vehicle access ramps are often used as a means for converting a conventional road vehicle for use by wheelchair users. The ramp provides access to the vehicle from the neighbouring ground. Various control mechanisms have been proposed for stowing the ramp when not in use. Some may require the user or companion to reach or stretch in a manner which is not acceptable, particularly if reaching down to ground level is required. Others may be fully automated and motorised, leading to significant potential issues of inconvenience or danger in the event of a malfunction.

Examples of the present invention provide a control mechanism for a vehicle access ramp which is pivotally mounted to be movable between an upright, stowed position, and a lowered position, the ramp providing ramp access to the vehicle from the neighbouring ground when in the lowered position, the mechanism comprising: a spring arrangement associated, in use, with the ramp; a releasable lock arrangement operable to lock the spring arrangement in a charged condition; a coupling arrangement operable to provide a releasable coupling between the spring arrangement and a vehicle access ramp; the coupling arrangement being arranged to couple the spring arrangement to the ramp when the ramp is in the stowed position, wherein movement of the ramp from the stowed position to a first intermediate position charges the spring arrangement; the lock arrangement is engageable as the ramp reaches the first intermediate position to lock the spring arrangement in the charged condition; and wherein the coupling arrangement is releasable at the intermediate position to allow the ramp to continue moving to the lowered position while the spring arrangement is locked; and wherein, when the lock arrangement is released with the ramp in the lowered position, the spring arrangement drives for the ramp from the lowered position to the or a second intermediate position; and wherein the ramp is movable back from the or the second intermediate position to the stowed position.

The coupling arrangement may comprise a link member which, in use, is secured to a ramp, and a drive member secured to the spring arrangement, the link member and the drive member being disconnectable to release the coupling arrangement. The link member may be pivotally secured to a ramp, in use, and have a first pivotal position in which the link member bears on the drive member, and a second pivotal position in which the link member is clear of the drive member. The drive member may comprise an engaging portion which engages the link member when the spring arrangement is being charged, to maintain the link member and the drive member in their connected condition. The engaging portion may be a recess. The link member may be released from the engaging portion by moving the ramp back from the first intermediate position towards the stowed position. The link member may swing clear of the drive member when the ramp is moved back from the first intermediate position towards the stowed position. The link member may be biased to swing clear. The link member may be biased by gravity. The coupling arrangement may comprise a guide surface which engages the link member as the ramp returns to the stowed position, to move the link member into engagement with the drive member.

The lock arrangement may engage a member of the coupling arrangement to cause the spring arrangement to be locked in the charged condition. The or a lock arrangement may be engageable with a member of the coupling arrangement to cause the ramp to be locked in the stowed position. The or at least one of the lock arrangements may engage the drive member.

The ramp may be manually movable from the stowed position to the first intermediate position, to cause the spring arrangement to be charged by manual effort. The ramp may be manually movable back from the first or the second intermediate position to the stowed position.

Examples of the present invention also provide a vehicle having a vehicle access ramp and a control mechanism as set forth above.

Examples of the present invention will now be described in more detail, by way of example only, and with reference to the accompanying drawings, in which:

Figs. 1a and 1b are simplified, schematic side views of an arrangement according to the embodiment of the invention, in use with a vehicle and ramp, showing the ramp in the stowed and open positions, respectively; and

Figs. 2 to 9 illustrate the arrangement of Fig. 1 at various stages of its operating sequence.

Overview

Fig 1a and Fig 1b show a control mechanism 10 for a vehicle access ramp 12 fitted to a vehicle 13 (indicated only schematically in the drawings). The ramp 12 is pivotally mounted to the vehicle 13 at an axis 14 to be movable between an upright, stowed position (Fig 1a), and a lowered position (Fig 1b). The axis 14 is shown in the drawings as being parallel with the ground. The ramp 12 provides ramp access to the vehicle 13 from the neighbouring ground when in the lowered position.

The mechanism 10 comprises a spring arrangement 16 (Fig 2 et al) associated, in use, with the ramp. A releasable lock arrangement indicated generally at 18 is operable to lock the spring arrangement 16 in a charged condition, as will be described. A coupling arrangement indicated generally at 20 is operable to provide a releasable coupling between the spring arrangement 16 and a vehicle access ramp 12. The coupling arrangement 20 is arranged to couple the spring arrangement 16 to the ramp 12 when the ramp 12 is in the stowed position. Consequently, movement of the ramp 12 from the stowed position to a first intermediate position charges the spring arrangement 16, as will be described. The lock arrangement 18 engages as the ramp 12 reaches the first intermediate position to lock the spring arrangement 16 in the charged condition. The coupling arrangement 20 is releasable at the intermediate position to allow the ramp 12 to continue moving to the lowered position while the spring arrangement is locked, and therefore without further charging the spring arrangement 16. When the lock arrangement 18 is released with the ramp 12 in the lowered position, the spring arrangement 16 drives for the ramp 12 from the lowered position to the or a second intermediate position. The ramp is movable back from the or the second intermediate position to the stowed position, as will be described.

Ramp mounting

The axis 14 is likely to be positioned at or near the height of the floorpan of the vehicle, in accordance with common practice. When the ramp 12 is in the stowed position, the ramp 12 extends up from the axis 14. The free edge 22 of the ramp 12 will be at a position significantly higher than the axis 14, depending on the dimensions of the ramp 12. The free edge 22 of the ramp 12 will therefore be readily accessible at a height which is significantly above the ground on which the vehicle 13 is standing. It is envisaged that the user will be able to grasp the free edge 22 without being required to bend or stretch to an unacceptable degree. The significance of this will become apparent from the following description.

Coupling arrangement and soring arrangement

The coupling arrangement 20 consists of two principal components, which are a drive member 24 and a link member 26.

The drive member 24 has a pivot mounting at 28, a side arm 30 and a skirt 32. The pivot mounting 28 mounts the drive member 24 to pivot around the axis 14. The side arm 30 projects away from the axis 14. The skirt 32 is generally planar in form and oriented generally transverse to the axis 14.

The side arm 30 defines a recess at 34 behind a lip 36 (Fig 3). In one configuration of the mechanism, the recess 34 receives a free end 38 of the link member 26 which is pivotally mounted at its other end 40 to the ramp 12. The drive member 24 is secured to a spring 42, here illustrated as a torsion spring. In order to turn the drive member 24 in one sense around the axis 14 (clockwise, as illustrated), it is necessary to work against the action of the torsion spring 42 so that as the drive member 24 is turned, the work which is done causes energy to be stored within the torsion spring 42. This process is here referred to as “charging” the spring 42, because the spring 42 is charged with energy by virtue of the work done. In an appropriate circumstance, as will be described, the charged spring 42 can be released to allow the spring 42 to relax and release the stored energy by driving the drive member 24.

The dimensions and geometry of the drive member 24 and the link member 26, particularly the depth of the recess 34, are chosen so that when the free end 38 of the link member 26 is engaged in the recess 34, movement of the ramp 12 away from the stowed position will force the drive member 24 to turn in like manner and while this is occurring, the free end 38 will be retained in the recess 34 to maintain this coupling. However, if the link member 26 is pivoted (relative to the ramp 12) to be free of the recess 34, by means of an operating sequence which will be described below, the coupling between the ramp 12 and the drive member 24 will be released, allowing some independence of movement of the ramp 12 and the drive member 24 around the axis 14.

Lock arrangement

The skirt 32 has a lock feature 44 which may be a notch, recess, aperture or other form. The lock arrangement 18 is mounted on the vehicle 13 at a fixed position relative to the axis 14. The skirt 32 moves past the lock arrangement 18 when the drive member 24 turns around the axis 14 and at one position around the axis 14, the lock feature 44 moves alongside the lock arrangement 18. At this position, the lock arrangement 18 is able to engage the lock feature 44, such as by shooting a bolt member (not illustrated) to engage the lock feature 44, thereby locking the drive member 24 against turning further around the axis 14. Withdrawing the bolt member releases the lock, allowing the drive member 24 to turn.

Re-engagement of the coupling A guide plate 48 is provided alongside the skirt 32 and has a notch 50 which provides a cam surface for engagement with a finger 52 projecting from the link member 26. In a manner which will be described, the cam surface provided by the notch 50 is shaped to engage the finger 52 to swing the link member 26 from a position in which it is out of engagement with the side arm 30, to a position in which the link member 26 is back in engagement with the side arm 30.

Operating sequence (phase 1)

The significance of the structures which have been described above, and the manner in which they function can now be described in more detail by describing the operating sequence for lowering and raising the ramp 12.

In the initial condition, the ramp 12 is in the stowed position illustrated in Fig. 1a. The control mechanism is illustrated on an enlarged scale in Fig 2. The ramp 12 is upright. The drive member 24 has moved to the limit of its range of motion in an anticlockwise sense (as illustrated in the drawings). The free end 38 of the link member 26 is engaged in the recess 34. The spring 42 is relaxed.

Lowering the ramp can now be initiated by the user gripping the free edge 22 of the ramp 12 and pulling on the ramp 12 to move it away from the stowed position. The ramp 12 begins to turn around the axis 14 (see Fig. 3) in a clockwise sense (as illustrated). As it does so, the engagement of the coupling arrangement 20 causes the ramp 12 to push on the side arm 30, through the link member 26, thereby causing the drive member 24 to turn in a clockwise sense (as illustrated). Turning the drive member 24 around the axis 14 causes work to be done on the spring 42 which therefore becomes charged. This work is done by the user pulling on the ramp 12. It is envisaged that this effort will not be inconvenient for many users, for various reasons. The height of the free edge 22 avoids the need for undue stretching or reaching. The dimensions of the ramp 12 provide a leverage advantage, reducing the force required to charge the spring 42.

The ramp 12 is pulled away from the stowed position until an intermediate position is reached (Fig 4). The ramp 12 has swung down to an intermediate position which may be at an angle of around 45°, but another angle could be chosen. The drive member 24 has turned with it, causing the spring 42 to become charged. The skirt 32 has turned to bring the lock feature 44 to the locking arrangement 18. The bolt mechanism 46 is preferably spring-loaded to engage automatically with the lock feature 44 as the lock feature 44 arrives. In this condition, the free end 38 of the link member 26 remains engaged in the recess 34.

Further clockwise movement of the ramp 12 is prevented in this condition because the skirt 32 is locked to prevent the drive member 24 from turning, which therefore blocks movement of the ramp 12 by virtue of the presence of the link member 26.

Releasing the coupling arrangement

When the user feels that the ramp 12 is blocked from further movement, or hears the locking arrangement 18 engage, or is provided with some other indication that the drive member 24 is locked, the user can pull the ramp 12 back toward the initial, stowed position by a small distance. During this reverse motion, the drive member 24 remains locked in position and therefore, the link member 26 is pulled clear of the recess 34. This allows the link member 26 to swing on the ramp 12 to a position clear of the side arm 30 (see Fig 5a and Fig 5b). Thus, the coupling between the ramp 12 and the drive member 24 is released. After release of the coupling, the drive member 24 remains locked in position by operation of the bolt mechanism 46.

Operating seguence (phase 2)

After the coupling arrangement has been released, the user can again reverse the movement of the ramp 12 so that it is again moving away from the stowed position. The link member 26 is no longer coupling the ramp 12 to the drive member 24, so this movement of the ramp 12 is not blocked by the locked condition of the drive member 24. There begins a second phase of movement in which the user may simply release the ramp 12, allowing the ramp to fall further, under its own weight, until reaching the ground (Fig 6 and Fig 1b). Although possible, it would be undesirable for safety reasons for this second phase of movement be unrestrained. Use of a counterweight, counterbalance, damper or equivalent mechanism is therefore desirable but is not illustrated in the drawings, in the interests of clarity.

When the ramp 12 reaches the ground, the ramp 12 becomes available for use by the user for ramp access to the vehicle 13.

In the condition of Fig 6, the drive member 24 remains locked with the spring 42 in its charged condition. The link member 26 is disengaged from the drive member 24.

Operating sequence (phase 3)

The third phase of movement commences when it is desired to close the ramp 12, that is, when it is desired to return the ramp 12 to the stowed condition of Fig 1a. The third phase of movement is initiated by releasing the locking arrangement 18 to free the skirt 32 by disengaging the lock feature 44. The drive member 24 is now once again free to turn around the axis 14. Thus, the spring arrangement 16 is no longer locked in its charged condition. The drive member 24 is thus driven to turn, by the spring arrangement 16. At some point after the drive member 24 begins to turn, the side arm 30 will come into engagement with the lower face of the ramp 12 (Fig 7). The angle at which this occurs will depend on the angle at which the ramp 12 has come to rest, which will in turn be affected by the height and slope of ground around the vehicle 13, the presence or absence of kerbs, and similar factors. When the side arm 30 comes into engagement with the lower face of the ramp 12 (Fig 7), the force provided by the spring 42 will thereafter cause the drive member 24 to push the ramp 12, so that the ramp 12 and the drive member 24 both turn toward the stowed condition (both turning anti-clockwise, as illustrated). A second intermediate condition will be reached (Fig 8). The drive member 24 has returned to its initial position, with the spring 42 now fully relaxed. Flowever, the ramp has not yet returned to the stowed condition because the released condition of the coupling arrangement 20 allows the ramp 12 to be at an intermediate inclination between the stowed condition and the lowered condition. The remaining arc of movement back to the stowed condition can be provided manually by the user, as follows.

Operating sequence (phase 4)

During this phase of operation, the user again grips the free edge 22 (which has returned to a convenient height above the ground) and pushes the ramp 12 towards the stowed condition of Fig 1a. This will require some effort on the part of the user but again, the free edge 22 is conveniently accessible.

The drive member 24 has already returned to its original position with the spring 42 relaxed, as noted above. However, in the condition of Fig 8, the link member 26 is still lying disengaged from the side arm 30. As the ramp 12 continues to turn (anticlockwise) the link member 26 rides over the age of the side arm 30 (Fig 9). As it does so, the finger 52 comes into engagement with the notch 50, thereby guiding the link member 26 to remain against or close to the side arm 30, overriding any bias which may be present. In due course, the ramp 12 returns to the upright position corresponding with the stowed condition and as it does so, the link member 26 returns into engagement with the side arm 30. This engagement may arise naturally by the effect of gravity causing the link member 26 to swing down, or may be encouraged by the cam action of the notch 50 acting on the finger 52.

The result is that the ramp 12 is once again in the stowed condition (Fig 2) and the coupling to the drive member 24 is once again engaged so that if the ramp 12 is pulled away from the stowed condition, the sequence described above will commence again.

In the example being described, the skirt 32 is provided with a second lock feature 54 which engages with the locking arrangement 18 when the ramp has returned to the stowed condition. Consequently, the ramp 12 becomes locked in the stowed condition because movement of the ramp 12 is prevented by engagement between the link member 26 and the side arm 30, which is in turn prevented from movement by engagement of the locking arrangement 18 with the second lock feature 54.

Concluding comments

Many variations and modifications can be made to the apparatus described above, without departing from the scope of the invention. In particular, many different alternative arrangements could be envisaged for the spring arrangement, the coupling arrangement and the locking arrangement. The spring arrangement could include mechanical springs such as compression springs, extension springs, flexion springs or torsion springs (as described), or could use gas springs, hydraulic springs or other alternative spring arrangements. Many alternative arrangements could be envisaged for a coupling arrangement which achieves releasable and re-engageable functions equivalent to those described above, and for a locking arrangement suitable for a chosen coupling arrangement and spring arrangement.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. A control mechanism for a vehicle access ramp which is pivotally mounted to be movable between an upright, stowed position, and a lowered position, the ramp providing ramp access to the vehicle from the neighbouring ground when in the lowered position, the mechanism comprising: a spring arrangement associated, in use, with the ramp; a releasable lock arrangement operable to lock the spring arrangement in a charged condition; a coupling arrangement operable to provide a releasable coupling between the spring arrangement and a vehicle access ramp; the coupling arrangement being arranged to couple the spring arrangement to the ramp when the ramp is in the stowed position, wherein movement of the ramp from the stowed position to a first intermediate position charges the spring arrangement; the lock arrangement is engageable as the ramp reaches the first intermediate position to lock the spring arrangement in the charged condition; and wherein the coupling arrangement is releasable at the intermediate position to allow the ramp to continue moving to the lowered position while the spring arrangement is locked; and wherein, when the lock arrangement is released with the ramp in the lowered position, the spring arrangement drives the ramp from the lowered position to the or a second intermediate position; and wherein the ramp is movable back from the first intermediate position or the second intermediate position to the stowed position.

2. A mechanism according to claim 1, wherein the coupling arrangement comprises a link member which, in use, is secured to a ramp, and a drive member secured to the spring arrangement, the link member and the drive member being disconnectable to release the coupling arrangement.

3. A mechanism according to claim 2, wherein the link member is pivotally secured to a ramp, in use, and has a first pivotal position in which the link member bears on the drive member, and a second pivotal position in which the link member is clear of the drive member.

4. A mechanism according to claim 2 or 3, wherein the drive member comprises an engaging portion which engages the link member when the spring arrangement is being charged, to maintain the link member and the drive member in their connected condition.

5. A mechanism according to claim 4, wherein the engaging portion is a recess.

6. A mechanism according to claim 4 or 5, wherein the link member is releasable from the engaging portion by moving the ramp back from the first intermediate position towards the stowed position.

7. A mechanism according to claim 6, wherein the link member is able to swing clear of the drive member when the ramp is moved back from the first intermediate position towards the stowed position.

8. A mechanism according to claim 7, wherein the link member is biased to swing clear.

9. A mechanism according to claim 8, wherein the link member is biased by gravity.

10. A mechanism according to any of claims 2 to 9, wherein the coupling arrangement comprises a guide surface which engages the link member as the ramp returns to the stowed position, to move the link member into engagement with the drive member.

11. A mechanism according to any of claims 2 to 10, wherein the or a lock arrangement is operable to engage the drive member.

12. A mechanism according to any preceding claim, wherein the lock arrangement is operable to engage a member of the coupling arrangement to cause the spring arrangement to be locked in the charged condition.

13. A mechanism according to any preceding claim, wherein the or a lock arrangement is engageable with a member of the coupling arrangement to cause the ramp to be locked in the stowed position.

14. A mechanism according to any preceding claim, wherein the ramp is manually movable from the stowed position to the first intermediate position, to cause the spring arrangement to be charged by manual effort.

15. A mechanism according to any preceding claim, wherein the ramp is manually movable back from the first or the second intermediate position to the stowed position.

16. A control mechanism for a vehicle access ramp, substantially as described above, with reference to the accompanying drawings.

17. A vehicle having a vehicle access ramp and a control mechanism as defined in any of claims 1 to 16.

18. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.