GB2285033A - Tail lift for vehicles - Google Patents

Abstract

Tail lift e.g. for a van has side frames 1 with a parallelogram linkage formed by pairs of links 7, 8 joined to U-shaped arms 18 carrying a platform 19. The arrangement is such that the platform is raised and moved into the vehicle to allow the load to be pushed further into the vehicle for carrying. The links 8 are joined by a torsionally stiff cross member 9. <IMAGE>

Description

LOAD LIFTING ARRANGEMENT FOR VEHICLES.

This invention relates to the provision of a facility for lifting and lowering loads onto and off from a vehicle.

It is well known that the manual loading and unloading of vehicles such as rear entry loading vehicles is inherently dangerous. In particular, there is always the certain risk of the load slipping during the loading and unloading operation. Furthermore, there is the additional risk that a person undertaking the loading and unloading is unknowingly so incorrectly handling the load as to be causing damage to his body.

Installations intended to provide a facility at the tail gate of a vehicle for handling a load are known. These known installations operate in the manner of a fork-lift units which in operation involve essentially vertical up or down movements. The movable platform of such apparatus is conventionally carried in guide columns located at the corners of the rear end of the vehicle body. One of the problems of such installations is that they are restricted to mounting to a van/lorry body often especially built which can accomodate/mount the vertical guides.

This reqirement effectively excludes their application to a considerable number of already available vehicles.

It is an object of the present invention to provide a lifting assembly that does not require purpose built vehicles for utilisation.

That is to say the lifting assembly of the invention can be mounted to vehicles not provided with the vertical guides and to existing vehicles such as vans, pick-up and flat-bed trucks and, if desired, to trailers.

Broadly, according to a first aspect of the invention there is provided a load handling facility which is not only able to effect displacement of a load in a vertical direction but also in transverse directions to the vertical direction.

In accordance with a further aspect of the invention the load handing facility can be fitted to the vehicle after the manufacture thereof.

Preferably, the load to be handled is supportable by a load handling facility that can be moved in such manner that the load can be horizontally moved and raised or lowered according to requirements and displaced to or from the interior of the vehicle to which the facility is fitted.

For a better understanding of the invention and to show how to carry the same into effect reference will now be made to the accompanying drawings in which: Figure 1 is a diagrammatic representation of a load handling facility incorporating the concepts of the invention when mounted within a vehicle and when in a setting for raising a load; and Figure 2 is a view illustrating the apparatus when stowed within the vehicle.

Referring now to Figure 1, this Figure illustrates an embodiment of the lifting apparatus of the invention when installed in a closed-in van having rear opening doors.

The apparatus incorporates a pair of side frames 1 (only one being visible in the Figure) which are to be located one to each side of the interior of a vehicle such as a light weight van.

The side frames 1 need to be very firmly secured within the vehicle. In a practical installation these side frames can be secured to especially provided attachment points provided in the floor of the vehicle or to any other relatively rigid and strong part of the vehicle structure such as, for example, the wheel arches.

The side frames 1 are of a generally trapizoidal form and serve to provide at the end of the side-frame adjacent the rear opening 3 to the vehicle 4 inclined sides 2 providing upper and lower pivot points 5 and 6. Thus, in the arrangement shown the line 7 joining the pivot points 5 and 6 slopes upwardly forwardly at an angle of substantially 45 degrees to the vertical.

An arm 8 is pivotally connected to the side frame so as to be pivotable about the pivot point 6. Since there is a side frame to each side of the vehicle, there will thus be two such arms 8. These arms 8 are joined by a torsionally stiff cr s member 9 which, therefore, effectively joins the two frames inclined members 2 at the pivot points 6 whereby the bar 9 is arranged effectively coaxial with the pivot axis of the pivot points 6.

A U-cross-section (channel) beam 10 is pivotally connected intermediate the ends 11 and 12 thereof to the free end 13 of the arm 7. Pivot points 14 and 15 are respectively provided at the beam ends 11 and 12. The pivotal connection between the beam 10 and the end 13 of the arm 8 is located at a pivot point 16 which is such that the four pivot points 5, 6, 14, and 16 effectively lie at the corners of a parallelogram linkage system. As may be seen from the Figure 1 a tension link 17 is pivotally interconnected between the beam 10 and the side frame 1 the associated connection being at the pivot points 6 and 14.

Each beam 10 when the load handling facility is in the position shown in Figure 1 extends as may be seen upwardly and forwardly, the length of each of the beams 10 being such that when the unit of the invention is installed in a vehicle 4 the lower end thereof 12 is adjacent the ground level 18.

A load receiving platform 19 is pivotally connected at the corners 20 thereof nearest to the vehicle to the two beams 10 The connections being at the lower end pivots 15 of these beams.

The surface area of this platform 19 defines the lifting area of the facility.

The platform 19 is maintained in a horizontal setting when in the position shown by cables, chains or hinged links 21 connected at their lower ends 23 to the platform and at their upper ends 24 to the beams 10 at locations intermediate the beam pivot points 15, 16 and nearer to the pivot 16.

The vertical displacement of the load receiving platform 23, and the beams 10 is effected by means of two single acting hydraulic piston units 25 one to each side frame 1 and operationally connected between the pivot points 14 and 6.

A ramp plate 26 is provided to the rear of the lower pivot points 6 of the side frames. The purpose of the ramp plate 26 is to facilitate displacement of loads over the torsion bar 9.

In using the load handling facility, it will be presumed initially that a load is present on the load receiving platform 23. On operation of the piston units 25 effectively to increase the length of the units between the pivot points 5 and 14 the pivot point 14 is caused to pivot around the pivot point 6. In otherwords, the uppermost end 11 of the beam 10 is lifted upwards and forwards whilst it separation from the pivot remains constant. Thus, the beam 10 is bodily caused to move upwards and forwards. During the initial parts of the overall movements of the beams 10 the load is simultaneously lifted upwards and horizontally moved towards the vehicle.

The lengths of the various elements of the linkage system are such that the overall geometry of the lingage system lifts the load receiving plate to the level of the interior of the vehicle before the load receiving plate has been moved sufficiently towards the vehicle to foul the entry of the load receiving plate (and thus the load) into the interior of the vehicle.

Once the load receiving plate 19 has cleared the floor level of the interior of the vehicle the load can be moved from the plate into the vehicle.

It will be appreciated that further operation of the piston units will displace the loading platform further into the vehicle until the lower ends 12 of the beams 10 are closely adjacent to the pivots 6 of the side frames 1.

As may be seem from Figure 2 when the beams 10 are in this position the the bars 8 and 17 are in an 'over centre' relationship to the pivots 6.

It will be understood that once the load receiving platform has been moved into the interior of the vehicle the load can be reboved by way of the ramp plate.

The fully inward position of the linkage system is shown in Figure 2.

Figure 2 also illustrates the stowed position for the load receiving plate, which as shown has been folded to an upstanding position by tilting the platform about the pivots 15. The Figure also shows in dashed lines the load receiving platform when in its lowered position.

Since as has been above mentioned the beams 10 have been moved, on lifting the load receiving platform to an 'over centre' condition it will be necessary when it is required to return the platform towards the ground position as shown in Figure 1 to move the beams 10 anti-clockwise to overcome the 'over centre' condition, this operation normally being effected by pushing or pulling on the beams or what ever part of the linkage system found convenient for this purpose.

Once the beams 10 have been displaced out of the 'over centre condition the lowering of the load becomes gravity aided and the load moves towards the ground. The rate of the lowering descent can be controlled by any convenient means such as, for example, by use of braking devices which could be provided by the inclusion of a flow restictor in the hydraulic piston unit fluid supply arrangements.

It will be appreciated that by using the hydraulic piston units the provision of overload facilities can be met by the use of operationaly simple relief valve arrangements for both the lifting and lowering operations.

In practical instllations it may well be found convenient to locate the various pivot points in locatations different from those specifically shown in the Figures. Clearly, such positional changes will be such as to satisfy particular geometries for the linkage system involved.

The above mentioned hydraulic piston units can if desired be replaced by screw jacks, cables operating in tension between the pivot ponts 6 and 16 etc. For such arrangements the operating power can be provided by the use of hand or foot pumps; winding hndles; or by electic motor drive, energised from the vehicle battery.

Claims (12)

1. A load handling device, which device is arranged to be able not only to effect displacement of a load in a vertical direction but also in transverse directions to the vertical direction.

2. A load handling device as claimed in claim 1, and wherein the device is adapted for mounting to a vehicle during and after manufacture ofthe vehicle.

3. A load handling device as claimed in claim 1 or 2, and wherein the load to be handled is supportable by the device in such manner that the load can be horizontally moved and raised or lowered according to requirements and displaced into or out from the interior of the vehicle to which the facility is fitted.

4. A load handling device as claimed in claim 1, 2 or 3, and including a pair of side frames which are adapted to to be locatable one to each side of the interior of a vehicle to which the device is to be mounted; such as a light weight van therebeing an arm is pivotally connected to each side frame so as to be pivotable about a first pivot point said arms being joined by a torsionally stiff cross member at the pivot points whereby the bar is arranged to be effectively coaxial with the pivot axis of the pivot points and wherein a U-cross-section beam is pivotally connected intermediate the ends thereof to the free end of each said the arm, said beams serving to mount a load receiving support means, the pivotal connection between each said beam and the associated arm being located at a second pivot point which is such that the two first pivot points and the two second pivot points effectively lie at the corners of a parallelogram linkage system.

5. A load handling device as claimed in claim 4, and further including a tension link pivotally interconnected between each beam and the associated side frame, and wherein the associated connections are located at said first and second pivot points.

6. A load handling device as claimed in claim 4 or 5, and wherein when the side frames are mounted to a vehicle, the side frames are foldable to a position in which the beams extend upwardly and forwardly relative to the vehicle fore and aft direction, and wherein the length of each of the beams is such that when the side frames are so folded the load support means is located adjacent to the ground.

7. A load handling device as claimed in claim 6, and wherein the load support means comprises a load receiving platform which is is pivotally connected at the corners thereof nearest to the vehicle to the two beams.

8. A load handling device as claimed in claim 7, and wherein the load receiving platform is maintained in a horizontal setting when in the position adjacent to the ground by cables, chains or hinged links connected at their lower ends to the platform and at their upper ends to the beams at locations intermediate the beam pivot points.

9. A load handling device as claimed in claim 8, and wherein the vertical displacement of the load receiving platform and the beams is effected by means of two single acting hydraulic piston units one to each side frame and operationally connected between the first and second pivot points.

10. A load handling device as claimed in claim 8 or 9 and wherein a ramp plate is provided to the rear of the lower pivot points of the side frames, said ramp plate serving to facilitate displacement of loads over the torsion bar.

11. A load handling device as claimed in claim 4, and wherein the side frames are of a generally trapizoidal form and serve to provide at the end of the side-frame adjacent the rear opening to the vehicle inclined sides providing upper and lower pivot points, the arrangement being such that the line joining these pivot points slopes upwardly and forwardly relative to the fore and aft direction of the vehicle at an angle of substantially 45 degrees to the vertical.

12. A load handling device constructed and arranged to operate substantially as hereinbefore described with rewference to the accompanying drawings.