GB2423071A

GB2423071A - Underfloor lift systems with latching mechanism

Info

Publication number: GB2423071A
Application number: GB0502539A
Authority: GB
Inventors: Adam Beck; Dennis John Wheatcroft; Paul John Edwards
Original assignee: Passenger Lift Services Ltd
Current assignee: Passenger Lift Services Ltd
Priority date: 2005-02-08
Filing date: 2005-02-08
Publication date: 2006-08-16
Anticipated expiration: 2025-02-08
Also published as: GB0502539D0; GB2423071B

Abstract

A lift system for mounting on a vehicle comprises a carriage 12 arranged to be movably mounted on the vehicle for movement in a longitudinal direction between a stowed position and a deployed position, and a latch mechanism 20 arranged to releasably secure the carriage 12 in the stowed position, the latch mechanism comprising a headed latch 22 mounted on the carriage, and a latch engaging member 24 arranged to be mounted on a fixed part of the vehicle and movable perpendicularly to the longitudinal direction to releasably engage the latch. As shown, the movable latch member 24 is pivotally mounted, spring 46 pressed to the engaged position and moved wither by an actuator 48 or a manual release lever 54.

Description

1 2423071

LIFT SYSTEMS

The present invention relates to lift systems, and in particular to lift systems that are arranged to be attached to vehicles, for example to lift passengers in wheelchairs into and out of the vehicles.

It is known to provide a lift that can be stowed in a stowed position, for example in a stowage box under the floor of a vehicle, and then moved into a deployed position from which it can be raised and lowered to lift and lower passengers. Typically the lift is supported on a carriage, which is movably mounted on the vehicle so that it can be moved between a stowed position and a deployed position, typically by sliding horizontally.

Some form of locking mechanism is generally required to lock the carriage in the stowed position when the lift is not in use. It is also generally required that this locking mechanism can be released by a powered actuation mechanism during normal automatic deployment of the lift, and also released manually, for example in the case of a power failure on the vehicle.

The present invention therefore provides a lift system for mounting on a vehicle, the system comprising a carriage arranged to be movably mounted on the vehicle for movement in a longitudinal direction between a stowed position and a deployed position, and a latch mechanism arranged to secure the carriage in the stowed position, the latch mechanism comprising a latch mounted on the carriage, and a latch engaging member arranged to be mounted on a fixed part of the vehicle and movable perpendicularly to the longitudinal direction to releasably engage the latch.

Preferred embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a schematic plan view of a lift system according to an embodiment of the invention; Figure 2 is a front view of a latch mechanism of the system of Figure 1; Figure 3 is a plan view of the latch mechanism of Figure 2; Figure 4 is a front view of the latch mechanism of Figure 2 in a released position; and Figure 5 is a front view of the latch mechanism of Figure 2 in a manually released position.

Referring to Figure 1, a lift system for a vehicle comprises a stowage box that is rigidly mounted on the vehicle, a carriage 12 slidably mounted within the stowage box 10, and a lift 14 mounted on the carriage 12. The carriage 12 is movable between a stowed position towards the rear 16 of the box 10 and a deployed position towards the front 18 of the box 10.

When the carriage 12 is in the stowed position the lift 14 is also in a stowed position, inside the box 10, substantially level with the carriage 12. When the carriage 12 is in the deployed position the lift 14 can be raised and lowered to lift passengers onto the vehicle, and lower them from the vehicle. A locking mechanism in the form of a latch mechanism is provided to releasably secure the carriage in the stowed position.

The latch mechanism comprises a latch 22 mounted on the carriage 12 and a latch engaging member 24 mounted on the rear wall 16 of the box 10.

The latch mechanism 20 is located centrally between the two sides 25a, 25b of the carriage 12. These are show schematically in Figure 1, and will now be described in more detail with reference to the remaining Figures.

Referring to Figure 2, which is a front view of the latch mechanism 20 in the direction of arrow A in Figure 1, and also Figure 3, the latch 22 is mounted on a bracket 26 on a cross member 28 forming part of the carriage. The bracket 26 supports the latch 22 in a position vertically below the cross member 28. The latch 22 comprises a shank 30 extending in the longitudinal direction beneath the cross member 28, and a head 32 at the end of the shank 30 closest to the rear of the box 10. The head 32 of the latch is of larger diameter than the shank 30, having a flat annular rear surface 34 facing in the direction towards the front of the box 10 and a front surface 36 that is domed, tapering inwards to a flat central portion 38 in its centre. The shank 30 of the latch 22 is threaded and a pair of adjustment nuts is threaded onto it, one on either side of the bracket 26, so that the position of the latch 22 can be adjusted in the longitudinal direction relative to the carriage.

The latch engaging member 24 comprises a lever that is pivotably mounted on a support plate 40, which in turn is mounted on the rear wall 16 of the box 10. The lever 24 is mounted such that it can rotate about an axis 42 extending in the longitudinal direction of the system. The lever 24 is rotatable about the axis 42 between an engaging position, as shown in Figure 2, in which it is substantially vertical, and one side 44 of the upper part 45 of the lever, towards its upper end 46, can engage against the rear face 34 of the latch head 32, and a releasing position, as shown in Figures 4 and 5, in which it is disengaged from the latch 22. A return spring 46 acts on the lower part 47 of the lever 24 below the pivot axis 42 to urge the lever 24 towards the engaged position. An actuator in the form of a screw jack 48 is arranged to drive an end cam 50 against the side 52 of the lower part 47 of the lever, opposite to the side 44 that engages with the latch 22. The actuator 48 is arranged to move the end cam in the horizontal direction so that it pushes against the side 52 of the lever 24 to push it from the engaging position to the releasing position, and in the opposite horizontal direction to allow the lever to return to the engaging position under the force of the return spring 46.

A manual release cable 54 comprises a cable inner 56 and a cable outer 58. The cable inner 56 is connected to the upper end 45 of the lever 24 and the end of the cable outer 58 is fixedly mounted on the support plate 40, by means of a cable support 60, in a position to the side of the upper part 54 of the lever opposite to the latch 22. The cable inner can therefore be pulled, by means of a manual release lever (not shown) to pull the lever from the engaging position to the releasing position against the force of the return spring 46. It will be appreciated that, if the release cable 54 is used to release the latch 22, the lower end 47 of the lever moves away from the actuator end cam 50, independently of the actuator 48, to release the latch 22.

As can best be seen in Figure 3, the side 44 of the lever 24 that engages the latch 22 has a bevelled edge 56, that is bevelled on the side facing away from the rear wall 16 of the box 10. This bevelled edge is arranged to be at the same angle, in this case about 45 to the longitudinal direction, as the tapered side 36 of the latch head 32. This edge 56 of the lever 24 is aligned with the latch 22 such that, if the lever 24 is in its engaging position, and the carriage 12 is moving towards the back of the box 10, the tapered side 36 of the latch head 32 engages the bevelled edge 56 of the lever, and pushes the lever 24, against the force of the return spring 46 out of the engaging position. As the carriage 12 moves into the stowed position, the side 44 of the lever rides over the side of the latch head 32 until the rear face 34 of the latch head 32 passes the rear face 62 of the lever 24, at which point the lever moves back into the engaging position behind the latch head 32, thereby preventing the latch 22, and hence the carriage 12, from moving back out of the stowed position.

In use, when the lift 14 is in the stowed position, the lever 24 is engaged behind the latch head 32 securing the lift in that position as shown in Figure 2. If the lift is deployed using the normal automatic deployment mechanisms, under the control of a system controller, the actuator 48 is arranged to push the lever 24 into the releasing position, as shown in Figure 5, and to hold it in that position for a predetermined time, in this case three seconds, while the controller causes the carriage 12 to be moved towards its deployed position. After that predetermined time the actuator retracts the end cam 50 allowing the lever 24 to return to the engaging position, as the carriage moves forward to the deployed position. If the lift is stowed again, the lever engages with the latch 22 to secure the lift in the stowed position as described above. The position of the latch 22 can be adjusted in the longitudinal direction so as to ensure that the lift and carriage are secured in the correct position when stowed.

If the lift needs to be deployed manually, the release cable inner 56 is pulled to move the lever 24 from the engaging position to the releasing position as shown in Figure 4. This causes the lower end 47 of the lever 24 to move away from the actuator end cam 50 which remains in its retracted position, and the upper part 45 of the lever 42 to disengage from the latch 22. This releases the latch 22 and allows the carriage and lift to be pulled manually towards the deployed position.

The embodiment described above has a number of advantages. As the latch is centrally mounted, it does not exert a twisting force on the carriage, either when the carriage moves into the stowed position, or if the carriage is pulled when the latch is securing it in the stowed position.

This helps to reduce wear on the system. Also as the actuator simply presses against the lever, and is not connected to it in any way, the lever cannot exert any significant lateral forces on the actuator. This reduces wear on the actuator. It is also easy to adjust the latch thereby adjusting the longitudinal position of the carriage in the stowed position. This is useful to compensate for tolerances in the mounting of the carriage relative to the stowage box.

It will be appreciated that various modifications to the embodiment described above can be made. For example the lever 24 could be horizontal in the engaging position and rotate away from horizontal into the releasing position. Also, the lever 24 could be replaced with a sliding member that slides horizontally or vertically in the plane transverse to the longitudinal direction between an engaging position and a releasing position.

Claims

1. A lift system for mounting on a vehicle, the system comprising a carriage arranged to be movably mounted on the vehicle for movement in a longitudinal direction between a stowed position and a deployed position, and a latch mechanism arranged to releasably secure the carriage in the stowed position, the latch mechanism comprising a latch mounted on the carriage, and a latch engaging member arranged to be mounted on a fixed part of the vehicle and movable perpendicularly to the longitudinal direction to releasably engage the latch.

2. A system according to claim 1 further comprising biasing means arranged to bias the latch engaging member into an engaging position in which it can engage the latch.

3. A system according to claim 1 or claim 2 further comprising actuation means arranged to move the latch engaging member into a releasing position in which it is disengaged from the latch.

4. A system according to claim 3 wherein the latch engaging member is arranged to be moveable from its engaging position to its releasing position independently of the actuation means.

5. A system according to claim 4 wherein the actuation means is arranged to move the latch engaging member by pushing against it.

6. A system according to any foregoing claim further comprising a manual release means arranged to be manually operable to move the latch engaging member from the engaging position into the releasing position.

7. A system according to any foregoing claim wherein the latch engaging member is pivotably mounted so that it is movable by pivoting.

8. A system according to claim 7 wherein the latch engaging member is pivotable about an axis that extends in the longitudinal direction.

9. A system according to any foregoing claim wherein the latch is arranged to push the latch engaging member out of the engaging position as the carriage moves towards the stowed position.

10. A system according to any foregoing claim wherein the latch mechanism is located substantially centrally between two sides of the carriage.

11. A lift system substantially as hereinbefore described with reference to any one or more of the accompanying drawings.

12. A vehicle including a lift system according to any foregoing claim.