GB2473268A

GB2473268A - Platform lift assembly for a vehicle

Info

Publication number: GB2473268A
Application number: GB0915597A
Authority: GB
Inventors: Kevin Woods
Original assignee: WEC GROUP Ltd
Current assignee: WEC GROUP Ltd
Priority date: 2009-09-08
Filing date: 2009-09-08
Publication date: 2011-03-09
Also published as: GB0915597D0

Abstract

A platform lift (10) for a vehicle (40) comprising a load platform (2) including a load surface (12) for carrying a load and a base surface (11); a connector (26,28) for connecting the platform (2) to a vehicle (4) configured to enable the platform (2) to move between raised and lowered positions, the connector (26,28) being pivotably connected to the platform (2) to enable the platform (2) to pivot about a pivot axis (A) between a vertical stowed orientation and a horizontal load receiving orientation; a first actuator (22) mountable to a vehicle (4) and connected to the platform (2) for moving the platform (2) in the horizontal orientation between the raised and lowered positions; and a second actuator (24) mountable to a vehicle (4) and connected to the platform (2) at a position spaced from the pivot axis (A) for moving the platform (2) between the vertical and horizontal orientations. The pivot axis (A) is positioned above the base surface (11) and the second actuator (24) is connected to the load platform (2) at a position spaced above the pivot axis (A) when the platform (2) is in the horizontal orientation.

Description

A PLATFORM LIFT ASSEMBLY

The present invention relates to a platform lift assembly for raising and lowering loads between the ground and the load space of a vehicle, and in particular but not exclusively to a tail lift for passenger vehicles such as an ambulance.

Passenger vehicles such as ambulances for transporting injured, infirm or disabled persons are commonly provided with tail lifts for raising and lowering passengers between the ground and the passenger compartment of the vehicle. Conventional tail lifts comprise a load carrying tail board and a mechanism for raising and lowering the tail board by moving the tail board from its initial vertical stowed position at the rear of the vehicle body into a horizontal position and then in substantially the same horizontal attitude to ground level and back again.

An example of such a conventional tail lift is presented in GB2372482 (Rumsey). In the arrangement described in Rumsey the tail board forms a rear closure of an ambulance when oriented vertically. The tail board is pivoted to a horizontal orientation by a hinge mechanism mounted to the lower surface of the tail board, to open the rear of the vehicle and provide a passenger platform to carry for example a wheeled stretcher or trolley. The tail board is lowered from this position towards ground level in substantially the same horizontal orientation. When close to the ground, the hinge mechanism prevents the tail board from laying flat against the ground in a horizontal orientation. As such, the tail board must to be tilted such that it defines a sloping ramped surface. This arrangement is undesirable for wheeled loads such as trolleys, wheelchairs etc which are caused to roll forward as the tail board approaches the ground and is tilted, presenting a hazard to the * occupant. This arrangement is also presents a hazard for conventional cargo loads which can slide from the platform and tip.

EP00238 19 (Peck) describes a tail lift arrangement which allows the tail board to contact the ground in a horizontal position to facilitate loading and unloading of the tail board.

However, the Peck arrangement includes a complex leverage mechanism requiring multiple levers and multiple pivot points. Such complex mechanisms increase the number of components and moving parts, and hence the cost of a tail lift assembly as well as being difficult to maintain.

It is therefore desirable to provide an improved tail lift which addresses the above described problems and/or which offers improvements generally.

According to the present invention there is provided a tail lift for a vehicle as described in the accompanying claims.

The present invention aims to obviate or at least mitigate the above described problems and/or to provide improvements generally.

According to the present invention there is provided a tail lift according to any of the accompanying claims.

In an embodiment of the invention, there is provided a platform lift for a vehicle comprising a load platform movable between a raised position and a lowered position, the load platform including a load surface for carrying a load and a base surface; a connector for connecting the load platform to a vehicle configured to enable the load platform to move between the raised and lowered positions, the connector being pivotably connected to the load platform to enable the load platform to pivot about a pivot axis between a vertical stowed orientation and a horizontal load receiving orientation; a first actuator mountable to a vehicle and connected to the load platform for moving the load platform in the horizontal orientation between the raised and lowered positions; and a second actuator mountable to a vehicle and connected to the load platform at a position spaced from the F pivot axis for moving the load platform between the vertical and horizontal orientations.

The pivot axis is positioned above the base surface and the second actuator is connected to the load platform at a position spaced above the pivot axis when the load platform is in the horizontal orientation.

Connecting the second actuator above the base surface enables the load platform to be rotated between the horizontal and vertical positions while ensuring the no part of the lifting or tilting mechanism extends below the base surface, thereby allowing the load platform to be maintained in a horizontal orientation when proximate or in contact with the ground, thereby preventing loads such as trolleys from inadvertently slipping or rolling off the tail board during unloading. In addition, providing a lifting and tilting mechanism with a two point connection to the load platform allows a simple construction which reduces the number of components and moving parts thereby reducing cost and simplif3'ing maintenance.

The platform lift may comprise at least one bracket mounted to the load platform having a base portion pivotally connected to the connector and a flange portion arranged above the base portion and pivotally connected to the second actuator. The bracket thereby provides a single piece component which connects the load platform to both the connector and the second actuator, thereby simplif'ing construction. The at least one bracket is arranged above the base surface of the load platform, thereby preventing obstruction of the base surface and ensuring consistent horizontal attitude of the load platform during raising and lowering.

The connector may comprise at least one cantilever arm having a first end pivotally mountable end to the vehicle and an opposing second end pivotally connected to the at least one bracket, the first actuator being pivotally connected to the at least one cantilever arm. The positioning of the pivot axis and the connection point of the second actuator enables the use of a simple cantilever lifting arrangement while still ensuring the constant horizontal attitude of the load platform during raising and lowering.

The at least one bracket comprises a pair of brackets connected to opposing sides of the tail board and the at least one cantilever arm comprises a pair of cantilever arms connected to the pair of brackets. Connecting the pair of brackets to opposing sides of the load platform enables the platform lift to be applied to any width of platform while ensuring the load surface remains unobstructed between the load floor of the vehicle and the load surface of the load platform.

The platform lift may comprise a linking member interconnecting the pair of cantilever arms to maintain them in corresponding rotational positions, the first actuator being connected to the linking member. As such, raising and lowering of the load platform is achieved by a three part connector and a single actuator.

The first actuator may be connected to only one of the pair of brackets. As such, tilting of the load platform is achieved by a single actuator and a single bracket.

The platform lift may comprise a bridge plate pivotally connected to the tail board and pivotable between a stowed position adjacent the load surface and a bridging position in which the bridge plate extends from the rear edge of the load platform to bridge a gap in use between the load platform and the vehicle load space. The bridge plate allows the load platform to be spaced from the vehicle to accommodate the top mounting of the pivot/connector brackets.

The action of pivoting the tail board between the horizontal position and the vertical position may cause the bridge plate to automatically fold over between the bridging position the stowed position. This ensures the gap between the load platform and the vehicle is bridged without requiring operator intervention.

The tail board may also be pivotable between the stowed position and a barrier position in which the bridge plate extends vertically when the load platform is in the horizontal position. The action of moving the tail board between the raised position and the lowered position causes the bridge plate to automatically fold over between the bridging position and a barrier position. Automatically moving the bridge plate to the barrier position prevents loads from rolling backwards off the end of the platform and avoids inadvertent contact with the lifting mechanism.

The second actuator is controlled to maintain the load platform in a horizontal orientation during movement between the raised and lowered positions. This prevents loads supported on the load platform from sliding or rolling off the platform during raising and lowering.

The invention will now been described by way of example only and with reference to the accompanying drawings, in which: Figure 1 shows a tail lift according to an embodiment of the invention with the tail board in the raised loading position; Figure 2 shows the tail lift of figure 1 with the tail board in the lowered position; Figure 3 is a side view of the tail lift of figure 1 with the tail board in the vertical stowed position; Figure 4 is a side view of the tail lift of figure 1 with the tail board in the horizontal raised loading position.

Referring to Figure 1, a tail lift 10 is connected to the rear of a vehicle 4 for raising and lowering loads between the load floor 6 of the vehicle 4 and the ground. The tail Lift 10 comprises a tail board 2 defining a load platform and a lift mechanism 8 for raising and lowering the tail board 2 and for pivoting the tail board 2 to a vertical stowed position.

The tail board 2 includes a load surface 12 for supporting a load during raising and lowering of the tail board. The loads carried by the tail board may include injured or infirm persons, either on foot or carried on a trolley, or wheel chair. Side rails 14 are positioned along the side edges of the tail board 2 and extend above the load surface 12. The side rails 14 extending longitudinally along the length of the tail board 2 and provide transverse load restraint to prevent loads from sliding or rolling off the side of the tail board 2. A hand rail 16 provides further support for foot passengers and acts as an additional side barrier to prevent loads from falling from the side of the tail board 2. The hand rail 16 is connected to one of the side rails 14 by hinges 18, and is pivotable between a stowed position adjacent the support surface and a vertical operable position. An additional hinged hand rail may also be provided on the opposing side rail 14 to provide support on both sides of the tail board 2.

Brackets 15 and 17 are connected to the rear end of the tail board 2. The brackets 15 and 17 are mounted to the rear ends of the side rails 14 on opposing sides of the tail board 2.

The brackets 15 and 17 comprise a substantially wedge shaped body having a rear box section and a sloping triangular front portion. Each bracket 15,17 comprises a substantially straight lower edge running parallel with the base surface 11. The brackets 15,17 are each welded either side of the respective side rail 14. The rear box sections 15a,17a of the brackets 15,17 define flange sections which extend above the base surface 11 and above the load surface 12. The lower edges 15b,17b positioned above and do not extend below the base surface 11.

The lifting mechanism 8 is connected to a rear cross beam 18 of the vehicle 4 located beneath the load floor 6 proximate the rear opening 20. The rear beam 18 extends transversely beneath the load floor 6 and may form part of the structural frame of the vehicle 4. The lifting mechanism compromises a first hydraulic actuating cylinder 22. The piston rod of first actuator 22 is pivotably connected to the cross beam 18 by bracket 24.

Cantilever arms 26 and 28 connect the tail board 2 to the vehicle. The cantilever arms 26,2 8 are pivotably mounted to the cross beam 18 by brackets 30 and 32 respectively. The pivot points of the first actuator 22 and the cantilever arms 26,28 are arranged such that the pivot point of the first actuator is vertically spaced above the pivot points of the cantilever arms 26,28 with the cantilever arms 26,28 sharing a common pivot axis. Each cantilever arm 26,28 is bent at an elbow portion 36. A cross bar 38 is provided which is pivotally connected to the first actuator 22. The cross bar 38 is rigidly connected to the elbow portions 36 of the cantilever arms 26,28, and as such interconnected and links the cantilever arms 26,28 to hold them in corresponding rotational positions.

The distal ends of the cantilever arms 26 and 28 are rotationally connected to brackets 15 and 17 respectively at pivot points 41 and 42 by pivot pins 21. The pivot pins 21 define a pivot axis A for the tail board 2. The tail board 2 is able to rotate about the pivot axis A between vertical and horizontal orientations and relative to the cantilever arms 26,28. The pivot axis A is spaced above the base surface 11. As such neither the brackets 15,17 or the cantilever arms 26,28 prevent the base surface 11 from contacting or being positioned a short distance from the ground thereby enabling the tail board 2 to be maintained in a horizontal orientation in the hilly lowered position.

A second hydraulic actuator 24 is pivotally mounted to the cross beam 18 by a mounting bracket 32 for tipping the tail board 2 between the horizontal and vertical orientations. The opposing end of the second actuator 24 is connected to an angled linkage 34 as shown in Figure 3. The linkage 34 pivotally connects to the bracket 17. As such the second actuator 24 is pivotally connected to the bracket 17 via the linkage 34. While a single actuator 24 is provided in the described embodiment, a further actuator may be provided on the opposing side of the tail board 2, connected to the bracket 15, such that both brackets 15,17 are connected to an actuator. Two actuators may be required for example to support wider and hence heavier tail boards, to prevent twisting of the tail board during rotation.

The pivotal connection point 40 between the linkage 34 and the bracket 17 is located toward the upper rear corner of the bracket 17. As such, the pivotal connection point 40 is spaced above the base surface 11 and above the pivot axis A of the tail board 2. The brackets 15,17 therefore each provide a two point linkage for connecting the tail board 2 with both the cantilever arms 26,28 (and hence the first actuator) and the second actuator 24, thereby providing a compact and simple arrangement, which minimises parts and is therefore minimises manufacturing and assembly time and hence cost.

As the connection point 40 with the second actuator 24 is spaced from the pivot axis A, extension and retraction of the second actuator provides a tangential force which causes rotation of the bracket 17 about the pivot axis A and hence rotation of the tail board 2 between the horizontal and vertical orientation. Here the term above' means vertically above the pivot axis A and base surface 11 when the tail board 2 is in the horizontal position. The relative positional relationship is maintained when the tail board 2 is in the vertical orientation, with the pivot connection 40 being spaced inwardly towards the vehicle 4 of the pivot axis A and the base surface 11.

Movement of the tail board 2 between the raised horizontal position in which the tail board 2 is level with the load floor 6 and the lowered position in which the tail board is in contact with or proximate the ground for unloading, is actuated by the first actuator 22. As the pivot axis of the first actuator 22 is vertically offset above the pivot axis of the cantilever arms 26,28, extension of the actuator 22 pushes downwards against the cross bar 38 to rotate the cantilever arms 26,28 Arranging the brackets 15,17 such that the projecting flange sections 15 a, 1 7a and hence the pivot connection points 40,42 are above the load surface 12 and the base surface 11 ensures that the base surface is unobstructed which enables the horizontal orientation of the tail board 2 to be maintained, while also enabling the simple cantilever lifting arrangement to be used.

As shown in Figure 3, in the vertical stowed position, a gap 50 is defined between the load surface 12 and the rear of the vehicle, which is required to accommodate the projecting flange sections 1 5a and I 7a of the brackets 15 and 17. This gap 50 is acceptable as the tail board 2 is not used, nor is it suitable to be used to form the rear closure of the vehicle.

When the tail board 2 is rotated to the horizontal loading position shown in Figures 1 and 4, the gap 50 between the tail board and the rear of the vehicle 4 is maintained. In contrast, in arrangements of the prior art which utilise the tail board as a rear closure, it is essential that the actuators are connected to the rear surface of the tail board as to connect to the load surface would prevent the tail board from being able to form a suitable closure due to the interference of the actuators with the vehicle body when closing the tail board.

To provide a continuous load surface between the load floor 6 of the vehicle 4 and the tail board 2, a bridge plate 52 is provided to bridge the gap 50, which eliminates any trip hazard and prevents trolley wheels becoming lodged. The bridge plate 52 is pivotally connected to the rear edge of the tail board 2 by a sprung hinge. The bridge plate is pivotable between a stowed position adjacent the load surface 12, a bridging position in which it is co-planar and engaged with the rear ledge 54 of the vehicle, and an intermediate barrier position in which the bridge plate 52 extends vertically when the tail board is in the horizontal position. Movement of the bridge plate between the barrier position and the bridging position is automated and caused by the action of moving the tail board between the raised and lowered positions. In addition, the action of pivoting the tail board between the horizontal position and the vertical position may cause the bridge plate to automatically fold over between the horizontal bridging position extending from the end of the tail board and a position in which the load surface of the bridge plate is adjacent the load surface of the tail board respectively.

When in the tail board 2 is in the vertical stowed position, the bridge plate 52 is biased to a position adjacent the load surface 12 by the sprung hinge. When the tail board 2 is moved to the horizontal loading position, the bridge plate is moved to the bridging position and rests against the rear ledge 54. As the tail board 2 is lowered from the raised loading position to the lowered position, it rotates relative to the cantilever arms 26,28. A cam member (not shown) connected to at least one of the cantilever arms 26,28 engages the bridge plate 52 and lifts it to the vertical barrier position, as shown in Figure 2. A spring connected to the bridge plate 52 provides a biasing force towards the cam member to prevent the bridge plate 52 continuing to fold over into contact with the load surface 12. In the barrier position, the bridge plate 52 prevents loads such as trolleys from rolling toward the vehicle during transfer from loading area to ground. In a similar manner to the lowering is proccess, as the tail board is lifted to the raised position, the cam member and the spring return the bridge plate to the bridging position.

During transit, the tail board 2 is raised from the ground and held in a stowed vertical position adjacent the rear closure of the vehicle 4, as shown in Figure 3. To hold the tail board 2 in the stowed vertical position, the second actuator 24 is held in the retracted position, such that the pivot connection point 42 is pulled rearwards and downwards, causing the bracket 17 to tilt rear rearwards about the pivot axis A pulling the tail board 2 to which it is connected to the vertical stowed position in which it is held adjacent the rear of the vehicle 4.

When it is required to unload the vehicle 4, for example to alight a passenger from the load space of vehicle 4 at a given destination, the tail board 2 is moved from the vertical stowed position as shown in Figure 3 to the raised horizontal loading position shown in Figure 1 and 4. To move the tail board 2 to the horizontal loading position, the second actuator 24 is controlled to extend, thereby pushing the pivot connection point 40 upwards and forwards, causing the tail board to rotate forward about the pivot axis A. When the horizontal orientation is reached, the tail board 2 is held in that orientation by holding the actuator 24 at a fixed extension and the tail board 54 is moved to the bridging position to bridge the gap 50. In addition, in the horizontal loading position the first actuator 22 acts to hold the tail board 2 in a level vertical position with the load floor 6 of the vehicle such that a load such as a trolley may be wheeled from the load floor 6 onto the tail board 2.

Once the load is securely positioned on the tail board 2, the lift mechanism 8 is operated to move the tail board 2 from the raised position to the lowered position. Specifically, the first actuator 22 is extended and urges against the cross bar 38 to rotate the cantilever arms 26,28 downwards. The second actuator 24 is maintained at a fixed extension, and as the tail board is pivotally mounted to the cantilever arms 26,28, this allows it to rotate relative to the cantilever arms 26,2 8 to remain in a horizontal orientation during lowering. When in the lowered position, with the tail board 2 remaining in the horizontal orientation, the load may be removed from the tail board 2. A ramp 56 is provided at the front edge of the tail board 2 to enabled wheeled loads to be more smoothly transported to the ground. The ramp may be in the form of a fixed slope, pivoting slope, or combined ramp and stop assembly.

It is evident that the platform lift as described above may be adapted to a wide variety of applications and is not necessarily limited to use as a tail lift for vehicles. For example, the tail lift as hereinbefore described may have marine applications as a gangway or gangplank.

Claims

CLAIMS1. A platform lift for a vehicle comprising: a load platform movable between a raised position and a lowered position, the load platform including a load surface for carrying a load and a base surface; a connector for connecting the load platform to a vehicle configured to enable the load platform to move between the raised and lowered positions, the connector being pivotably connected to the load platform to enable the load platform to pivot about a pivot axis between a vertical stowed orientation and a horizontal load receiving orientation; a first actuator mountable to a vehicle and connected to the load platform for moving the load platform in the horizontal orientation between the raised and lowered positions; and a second actuator mountable to a vehicle and connected to the load platform at a position spaced from the pivot axis for moving the load platform between the vertical and horizontal orientations, wherein the pivot axis is positioned above the base surface and the second actuator is connected to the load platform at a position spaced above the pivot axis when the load platform is in the horizontal orientation.
2. The platform lift of claim 1 frirther comprising at least one bracket mounted to the load platform having a base portion pivotally connected to the connector and a flange portion arranged above the base portion and pivotally connected to the second actuator.
3. The platform lift of claim 2 wherein the connector comprises at least one cantilever arm having a first end pivotally mountable end to the vehicle and an opposing second end pivotally connected to the at least one bracket, the first actuator being pivotally connected to the at least one cantilever arm.
4. The platform lift of claim 3 wherein the at least one brackets comprises a pair of brackets connected to opposing sides of the tail board and the at least one cantilever arm comprises a pair of cantilever arms connected to the pair of brackets.
5. The platform lift of claim 4 comprising a linking member interconnecting the pair of cantilever arms to maintain them in corresponding rotational positions, the first actuator being connected to the linking member.
6. The platform lift of claim 4 or 5 wherein the first actuator is connected to one of the pair of brackets.
7. The platform lift of any one of claims 2 to 6 wherein the at least one bracket is arranged above the base surface of the load platform.
8. The platform lift of any preceding claim comprising a bridge plate pivotally connected to the tail board and pivotable between a stowed position adjacent the load surface and a bridging position in which the bridge plate extends from the rear edge of the load platform to bridge a gap in use between the load platform and the vehicle load space.IS
9. The platform lift of claim 8 wherein the action of pivoting the tail board between the horizontal position and the vertical position causes the bridge plate to automatically fold over between the bridging position the stowed position.
10. The platform lift of claim 8 or 9 wherein the tail board is pivotable between the stowed position and a barrier position in which the bridge plate extends vertically when the load platfonn is in the horizontal position.
11. The platform lift of claim 8 or 9 wherein the action of moving the tail board between the raised position and the lowered position causes the bridge plate to automatically fold over between the bridging position and a barrier position.
12. The platform lift of any pieceding claim wherein the second actuatui is euntiulled to maintain the load platform in a horizontal orientation during movement between the raised and lowered positions.