GB2180818A - Improvements in vehicle tail lifts - Google Patents

Abstract

A vehicle tail lift has a latch assembly (15) for holding the platform (12) to one of the runners (14) in the stowed position of the platform, an anchor assembly (25) for holding the platform against one of the columns (10) in the stowed position of the platform and the upper end position of the runners, and a hydraulic lock to maintain the runners in the upper end position. <IMAGE>

Description

SPECIFICATION Improvements in vehicle tail lifts This invention relates to vehicle tail lifts.

"Vehicle tail lift" is a term commonly used in the art meaning a lifting device which is designed to be attached to a vehicle, normally, though not necessarily at the rear, it could be attached at the side, for example, or even inside the vehicle.

The invention provides a vehicle tail lift of the kind comprising a pair of parallel, spaced apart, rigid, upright guide members, and a platform assembly which is movable relative to the guide member to and from an upper end position, where the platform assembly includes a pair of runners each of which travels up and down a respective guide member, and a platform which is hingedly mounted on the runners and which is pivotable between a load carrying position and a stowed position, and further comprising releasable latch means operable between the platform and one of the runners for holding the platform to the said runner in its stowed position, releasable anchor means operable between the platform and one of the guide members when the platform assembly is in its upper end position and the platform is in its stowed position for holding the platform to the said one guide member, and means for maintaining the platform assembly in its upper end position.

By way of example, an embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is an elevational view of a vehicle tail lift according to the invention, Figure 2 is a plan view showing in detail the latch assembly (in its open position) of the lift shown in Fig. 1, Figure 3 is an elevation view of the latch assembly of Fig. 2, Figure 4 is a perspective view showing in detail the anchor assembly of the lift shown in Fig. 1 and Figure 5 is a plan view of an alternative anchor assembly including means for preventing lateral disengagement.

A vehicle tail lift, as shown in Fig. 1, comprises a pair of upright columns 10, and a platform assembly 11 that is movable relative to the columns 10 to and from an upper end position. The platform assembly 11 comprises a platform 12 which is hingedly mounted at either side, as at 13, to a runner 14. The runners 14 each travel up and down a respective column 10. The platform 12 is pivotable between a load carrying position, which is preferably horizontal, and a stowed position (shown in Fig. 1), which is preferably vertical.

The tail lift of Fig. 1 includes a latch assembly 15, which is shown in detail in Figs. 2 and 3. The latch assembly 15 comprises a latch 16 which is pivotally mounted to runner 14 by means of a shaft 17. The latch 16 has a recess 18 therein, part of which recess is formed as an abutment face 19. Attached to the side of the platform 12 there is a stop 20. An abutment face 21 provided on the stop 20 is arranged to be contacted by the abutment face 19 of the latch 16 when the latch is pivoted into position in order to hold the platform 12 to runner 14. This is the stowed position of the platform, which is preferably vertical. The latch 16 conveniently incorporates a return spring 22 which is arranged to urge the latch towards it stop engaging position (i.e. in the direction of arrow A).Also, both the latch 16 and stop 20 conveniently have ramped surfaces, 23 and 24 respectively, so that as the platform 12 is moved towards to its stowed position (in the direction of arrow B), the latch 16 is pivoted clear of the stop 20, and when the platform 12 has reached its stowed position, the return spring 22 urges the latch 16 into its stopengaging position.

The tail lift of Fig. 1 also includes an anchor assembly 25, as shown in detail in Fig. 4.

The anchor assembly 25 here comprises a wedge-shaped block 26 which is fixed to the side of the platform 12 and which is slidable into engagement with a tapering striker plate 27 which is fixed to the column 10. As the platform assembly 11 reaches its upper end position with respect to the column 10, with the platform 12 in its stowed position, block 26 encounters striker plate 27 and is retained thereby, holding the platform assembly against the column 10. The platform assembly is thus held in positive contact with the column whilstever it is maintained in its upper end position.

An alternative anchor assembly shown in Fig. 5 includes means for preventing lateral disengagement of the block and striker plate comprising stops 30 and 31 formed as shoulders on the block 26a and striker plate 27a respectively.

The stops 30, 31 are each formed on the block and striker plate with a taper so as to offer a lead in during engagement. The shoulders act to prevent disengagement of the anchor assembly due to misalignment, wear or structural deflection of the tail lift.

In the tail lift of Fig. 1, the means for maintaining the platform assembly in its upper end position is in the form of a control device incorporated into the platform assembly driving mechanism. The platform assembly is driven up and down by a pressure fluid operated ram acting via a linkage, such as cables, on the platform assembly. The ram is supplied with pressure fluid from a power pack, which has the usual reservoir and control valves for actuation by an operator. In this lift, in addition to the control valve on the power pack, there is a non-return valve on the ram. This acts to allow pressure fluid to be delivered to the ram but automatically prevents fluid from leaving the ram. The non-return valve thus serves as a safety device to prevent loss of fluid from the ram, which ensures that the platform assembly in maintained in position.

An operator can open the non-return valve to lower the platform assembly only by acutating a solenoid which is incorporated into the nonreturn valve.

Preferably, the anchor assembly is provided at an upper corner of the platform, to minimise the risk of trapping an operator's fingers, and the assembly preferably includes a finger guard 28.

Preferably, the latch assembly is provided on the nearside of the vehicle so that an operator can control the lift from the kerb side of the vehicle. For preference, the latch and anchor assemblies are provided on opposite sides of the platform. For extra security, anchor assemblies may be provided on both upper sides of the platform and latch assemblies may also be provided on both sides of the platform. In the latter case, means may be provided to hold one latch open while the other latch is opened so that a single operator may work the lift.

Claims (13)

1. A vehicle tail lift of the kind comprising a pair of parallel, spaced apart, rigid, upright guide members, and a platform assembly which is movable relative to the guide members to and from an upper end position, where the platform assembly includes a pair of runners each of which travels up and down a respective guide member, and a platform which is hingedly mounted on the runners and which is pivotable between a load carrying position and a stowed position, and further comprising releasable latch means operable between the platform and one of the runners for holding the platform to the said runner in its stowed position, releasable anchor means operable between the platform and one of the guide members when the platform assembly is in its upper end position and the platform is in its stowed position for holding the platform to the said one guide member, and means for maintaining the platform assembly in its upper end position.

2. A tail lift as claimed in Claim 1 wherein the said one runner associated with the latch means is on the opposite side of the platform to the said one guide member associated with the anchor means.

3. A tail lift as claimed in Claim 1 or Claim 2 wherein the latch means comprises a latch member which is pivotably mounted on one of the platform and the said one runner, and which is engageable with a stop member on the other of the platform and the said one runner.

4. A tail lift as claimed in Claim 3 wherein the latch means further comprises means to bias the latch member towards its position engaging the stop member.

5. A tail lift as claimed in Claim 4 wherein the biassing means is a helical spring.

6. A tail lift as claimed in any preceding claim wherein the anchor means comprise a tenon element on one of the platform and the said one guide member, which is slidable into engagement with a mortise element on the other of the platform and the said one guide member.

7. A tail lift as claimed in Claim 6 wherein at least one of the mortise and tenon elements is tapered such that when the anchor means is fully engaged, the mortise and tenon elements are wedged together and the platform is held positively in contact with the said one guide member.

8. A tail lift as claimed in either of claims 6 or 7 wherein the anchor means include means for preventing lateral disengagement of the tenon and mortise elements.

9. A tail lift as claimed in any preceding claim wherein the means for maintaining the platform assembly in its upper end position comprises an automatically acting control device in the platform assembly driving mechanism.

10. A tail lift as claimed in claim 9 wherein the said driving mechanism includes a pressure fluid operated ram and the control device comprises a non-return valve arranged to prevent release of pressure fluid from the ram.

11. A tail lift as claimed in claim 10 wherein the non-return valve is operable to allow release of fluid from the ram by means of a solenoid.

12. A vehicle tail lift substantially as here it before described with reference to and as shown in the accompanying drawings.

13. A vehicle comprising a tail lift as claimed in any preceding claim.