GB2418660A

GB2418660A - Impact absorber for forklift truck

Info

Publication number: GB2418660A
Application number: GB0519794A
Authority: GB
Inventors: Helen Monk
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-09-29
Filing date: 2005-09-29
Publication date: 2006-04-05
Anticipated expiration: 2025-09-29
Also published as: GB2418660B; GB0421605D0; WO2006035222A1; GB0519794D0

Abstract

A load back rest (6, Fig 2) of a fork lift truck (1) is fitted with an impact absorbing device 10, 20, (30) to reduce or eliminate damage to the load caused by impacts between the load and the load back rest (6) during loading and transportation. The impact absorbing device 10, 20, (30) comprises an elongate body of rubber or the like, either hollow or solid, mounted to the load back rest (6) such that a load rested on the load back rest (6) will contact the device first. The elongate body preferably has a convex load contact portion 11, 21, (31). For a load back rest (6) constructed from narrow steel bars (7), the elongate body has a recess 12 configured to receive an edge of a bar (7). For a load back rest constructed from L-section steel members (37 Fig 8), the elongate body instead has a flat contact surface (32) and is attached with straps, ties or the like.

Description

24 1 8660

IMPACT ABSORBER

The present invention relates to an impact absorbing device. More particularly, but not exclusively, it relates to an impact absorber for protecting a load lifted by a fork lift truck.

Fork lift trucks and the like are widely used for transporting, loading and unloading a wide variety of products. The forks of a fork lift truck conventionally comprise a pair of generally horizontally-extending tines, each having an upright portion adjacent a proximal end. The upright portions are each mounted to a common cradle such that the tines extend substantially parallelly each to the other. The cradle is moveably mounted to a generally vertically- extending frame on a frontal aspect of the fork lift truck such that the cradle and tines may be raised and lowered as a unit, travelling up and down the frame. The tines are positioned under a load to be lifted, which is normally also rested against the upright portions for stability.

For bulky loads, particularly those that are not completely rigid, these upright portions do not provide sufficient stability (e.g. for upper elements of a stack of worktops, chipboard panels, etc. or for an upper portion of a flexible bag or other non-rigid container). The fork lift is then frequently fitted with a load back rest, comprising a metal framework mounted to the moveable cradle and extending upwardly above the upright portions of the tines. Bulky, tall and/or non-rigid loads can thus be rested against the load back rest while being lifted and transported.

Although such load back rests allow more types of load to be carried safely and stably, there are drawbacks. The load back rest is usually constructed from steel bars. Since it is lifted along with the load, its weight must be kept down, so the bars will be as narrow as possible, compatible with the strength required. Also, the bars normally have a rectangular cross- section, with relatively sharp corners. Thus, there is a risk that when the load comes into contact with the load back rest, whether flat-on to the bars, or worse at an angle so that it catches a bar corner, it may be seriously damaged. For example, if an edge of a worktop is chipped, it may become worthless. Brittle items may be cracked or smashed. Bags may be torn open, spilling their contents. However careful a fork lift driver may be, there will inevitably be some impacts between the load and the load back rest. A typical builders' merchant or DIY hypermarket may suffer handling losses equivalent in value to around 0.5% of its gross turnover.

It is hence an object of the present invention to provide a means to obviate the above problems and to reduce the damage to loads occasioned by impacts with the load back rest of a fork lift truck.

According to a first aspect of the present invention, there is provided an impact absorbing device mountable to a load back rest as defined herein of a fork lift truck or the like, comprising an elongate body of resilient material having a load contact face and being so mountable to a portion of the load back rest that said load contact face is interposable between the load back rest and a load supported thereby.

Preferably, the load contact face is convexly rounded.

Advantageously, the elongate body comprises deformable cavity means, optionally extending longitudinally thereof.

Optionally, said cavity means extends adjacent the load contact face.

Preferably, the elongate body comprises a resilient plastics material.

Advantageously, the elongate body comprises an elastomeric material.

Optionally, the elongate body comprises a natural or synthetic rubber material.

The elongate body may comprise a polyurethane material.

Preferably, the elongate body comprises a single unitary moulding, extension, casting or the like.

The elongate body may have a substantially constant cross-sectional profile.

In a first embodiment, adapted for use with a load back rest comprising at least one narrow elongate member, the elongate body of the impact absorbing device is provided with elongate slot means adapted to accommodate an edge of said narrow elongate member.

Preferably, said elongate slot means is adapted to receive said edge Trippingly.

Advantageously, the elongate body is provided with a pair of longitudinal rib means, extending therefrom remotely from the load contact face and defining said elongate slot means therebetween.

Said longitudinal rib means may be resiliently deformable to accommodate said edge.

In a second embodiment, adapted for use with a load back rest comprising at least one elongate L-section member, the elongate body of the impact absorbing device is provided with a substantially flat back rest contact face mountable to an outer face of said L-section member.

Preferably, the impact absorbing device is provided with fastening means to mount it to the load back rest.

Advantageously, said fastening means comprise releasable fastening means.

Said fastening means may be engageable with the load back rest without modification thereof.

Alternatively, the fastening means may be engageable with aperture means formed in the load back rest to cooperate therewith.

According to a second aspect of the present invention, there is provided a load back rest as herein defined provided with at least one impact absorbing device as described in the first aspect above.

The load back rest may comprise a plurality of narrow elongate metal members, optionally rectangular-section steel strips or bars.

The load back rest may then comprise an impact absorbing device as described in the first embodiment of the first aspect above.

The load back rest may comprise a plurality of elongate L-section metal members, optionally L-section steel profiles.

The load back rest may then comprise an impact absorbing device as described in the second embodiment of the first aspect above.

According to a third aspect of the present invention, there is provided a vehicle provided with a fork lift arrangement comprising a load back rest as described in the second aspect above.

According to a fourth aspect of the present invention, there is provided a method of producing a load back rest for a fork lift truck or the like comprising the steps of providing a load back rest comprising a plurality of elongate metal members, providing at least one impact absorbing device as described in the first aspect above, and mounting said at least one impact absorbing device to at least one said metal member.

The method may comprise the step of trimming said at least one impact absorbing device to a desired length.

Embodiments of the present invention will now be more particularly described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a typical fork lift truck fitted with a load back rest; Figure 2 is a perspective view of a typical load back rest separated from a fork lift truck; Figure 3 is a perspective view of a first impact absorber embodying the present invention; Figure 4 is a cross-section of the impact absorber shown in Figure 3; Figure 5 is a cross-section of the impact absorber shown in Figure 3, in position on a bar of a load back rest; Figure 6 is a crosssection of a second impact absorber embodying the present invention; Figure 7 is a perspective view of a third impact absorber embodying the present invention; and Figure 8 is a cross-section of the impact absorber shown in Figure 7, in position on an alternative form of load back rest.

Referring now to the Figures, and to Figure 1 in particular, a typical fork-lift truck 1 is provided with a lifting arrangement comprising two generally horizontal tines 2 (the "forks") extending outwardly from the truck 1 and parallelly, each to the other. Each tine 2 has a generally vertically-extending upright 3 at its proximal end; both uprights 3 are mounted to a cradle 4. The cradle 4 is mounted in turn to a generally vertically aligned lifting frame 5, here mounted to a frontal aspect of the truck 1. The cradle 4 and hence the forks 2 may be raised and lowered up and down the lifting frame 5 by a powered rack and pinion arrangement, or the like.

In use, the forks 2 are manoeuvred under a load, then lifted until the load is supported thereon. In practice, as an intermediate step, the forks 2 are tilted slightly upwardly towards their distal tips and the uprights 3, cradle 4 and lifting frame 5 are tilted slightly towards the truck at their upper ends, which encourages the load to settle stably and securely against the uprights 3.

A truck I such as that shown, intended for use handling tall, bulky or stacked loads, is usually provided with a load back rest 6, mounted to the cradle 4 so that it extends generally vertically above and roughly coplanarly with the cradle 4 and uprights 3. A portion of the load extending above the uprights 3 will thus be able to lean on the load back rest 6, which moves up and down with the forks 2 and hence with the load. Clearly, the load back rest 6 can be dimensioned to suit a particular size of load.

A typical load back rest 6, as shown in Figure 2, is made from narrow rectangular-section steel bars 7, welded together. To accommodate the main stresses imposed thereon, the bars 7 are relatively deep in a foreand-aft direction, but to keep weight down they have a relatively narrow frontal aspect 8 (for example, bars with a cross-section of ten millimetres by fifty millimetres are often used). The rectangular section of the bars 7 also leads to the load back rest 6 having relatively sharp edges. Thus, if a load is brought into contact with the load back rest 6 too rapidly, and particularly if it hits one portion of the load back rest 6 before it contacts a remainder thereof, there is a risk of the load being chipped, bent, torn or otherwise damaged.

A first impact absorber 10 of the present invention for use with the load back rest 6 is shown in Figures 3 and 4. The first impact absorber lO comprises an elongate body of a resilient material, typically a tough, durable natural or synthetic rubber or other elastomer (e.g. polyurethane) , with a substantially constant cross-section. The first impact absorber 10 has a substantially hemi-cylindrical load contact portion l l and a rectangular-section longitudinal recess 12 opposite to this, flanked by a pair of flanges 13. A generally hemi-cylindrical cavity 14 extends longitudinally of the impact absorber lO, within the load contact portion 11. The impact absorber 10 may be made by extrusion, injection moulding or any other

suitable process.

The first impact absorber 10 is mounted to the load back rest 6 as shown in Figure 5. The narrow frontal aspect 8 of a steel bar 7 of the load back rest 6 is inserted into the recess 12 of the impact absorber 10, which is dimensioned to accommodate it. Ideally, the flanges 13 grip the bars 7 resiliently to hold the impact absorber lO in position. In any case, they act to oppose lateral movement of the impact absorber to relative to the load back rest 6. In most cases, conventional ties, clips, straps or other fastenings would also be provided, securely encircling both the impact absorber l O and the respective bar 7.

When a load is brought into contact with the load back rest 6, it thus first comes into contact with the load contact portion l l, which has no sharp corners, and is in any case made of resilient material and has a deformably collapsible cavity 14, all of which help to absorb impacts and prevent damage to the load. Once the load is in place, the impact absorber 10 is held securely between the load and the bars 7 of the load back rest 6.

The impact absorber 10 may be supplied in standard lengths that may be cut to match the lengths of the bars 7 of the particular load back rest 6 being used. Depending on the particular load or loads to be handled, each bar 7 of the load back rest 6 may be protected with an impact absorber 10, or only those bars 7 or portions of bars 7 likely to be contacted.

A second impact absorber 20, shown in Figure 6, has a recess 12 to accommodate the bars 7 of the load back rest 6, flanked by two flanges 13 to grip the respective bar 7, as for the first impact absorber 10. However, it has a load contact portion 21 that is relatively larger than that of the first 10, being almost cylindrical in cross-section, and also has a relatively much smaller and cylindrical cavity 24 extending longitudinally thereof. It is thus adapted to sustain heavier impacts than the first impact absorber 10. Impact absorbers of this general type may be produced with no cavity at all, or with a cavity intermediate between those shown, depending on the magnitude of the impacts likely to result from the loads to be carried. For example, sheets of thin ply or laminate may only require an impact absorber dimensioned and configured for light impacts, while medium-density fibreboard (MDF) panels are much heavier and tend to impact the load back rest 6 much harder, so require more solid and robust impact absorbers. In general, the cavity 14, 24 should be as large as possible, to reduce both raw material costs and the weight of the impact absorber 10, 20. It is also envisaged that the impact absorbers could be made from materials having differing resilience, depending on the impacts to be absorbed, as long as the material of the load contact portion 11, 21 is sufficiently tough to stand up to repeated impacts without significant damage.

A small proportion of load back rests are not made of rectangular section steel bars 7 as shown, but instead comprise L-section steel members, with a flat surface of the L aligned towards the load. Although this might to an extent spread the impact from a load, the load back rest would still have relatively sharp corners and would still be made of a hard, rigid material that could easily damage a load.

For use with such load back rests, a third impact absorber 30 is provided. The particular example shown in Figure 7 comprises an elongate moulding or extrusion of rubber or other elastomer, with a generally hemi- cylindrical load contact portion 31 and a substantially flat mounting portion 32. A generally hemi-cylindrical cavity 34 extends longitudinally of the impact absorber 30, which thus has a generally D-shaped cross- section (again, variants without the cavity 34 or with proportionately smaller cavities 34 may be used for heavier loads).

The third impact absorber 30 is mounted to an L-section member 37 of a load back rest as shown in Figure 8. The mounting portion 32 is disposed along a frontally-aligned arm 38 of the L-section member 37. L-section steel stock is available in standard sizes, and preferably, as shown, the third impact absorber 30 is dimensioned to correspond to a width of the arm 38 (or to overlap slightly to each side). While it could be bolted, riveted or glued in place, it is believed that most users would prefer a removable mounting arrangement which leaves the load back rest unmodified (for example, holes for bolts might be perceived as weakening the structure). It is therefore envisaged that the third impact absorber 30 would be held in place by conventional plastic ties, straps or with Jubilee clips or the like (Jubilee is a registered trade mark).

As for the first 10 and second 20 impact absorbers, the third impact absorber 30 will always be contacted first by a load brought into contact with the load back rest. Through its shape, its deformable cavity and the resilience of the material from which it is made, impacts will be absorbed and damage to loads will be greatly reduced.

A further benefit of each of the impact absorbers 10, 20, 30 shown is that when they are in position, they will extend slightly forwardly of a load-contacting surface of the uprights 3.

Thus, movement of the load will be cushioned, at least partially, before a lower portion thereof contacts the uprights 3.

Claims

1. An impact absorbing device mountable to a load back rest as defined herein of a fork lift truck or the like, comprising an elongate body of resilient material having a load contact face and being so mountable to a portion of the load back rest that said load contact face is interposable between the load back rest and a load supported thereby.

2. An impact absorbing device as claimed in Claim 1, wherein the load contact face is convexly rounded.

3. An impact absorbing device as claimed in either Claim 1 or Claim 2, wherein the elongate body comprises deformable cavity means, optionally extending longitudinally thereof.

4. An impact absorbing device as claimed in any one of the preceding claims, wherein the elongate body comprises a resilient plastics material.

5. An impact absorbing device as claimed in any one of the preceding claims, wherein the elongate body comprises a single unitary moulding, extension, casting or the like.

6. An impact absorbing device as claimed in any one of the preceding claims, wherein the elongate body has a substantially constant crosssectional profile.

7. An impact absorbing device as claimed in any one of the preceding claims, adapted for use with a load back rest comprising at least one narrow elongate member, the elongate body of the impact absorbing device being provided with elongate slot means adapted to accommodate an edge of said narrow elongate member.

8. An impact absorbing device as claimed in Claim 7, wherein said elongate slot means is adapted to receive said edge Trippingly.

9. An impact absorbing device as claimed in Claim 8, wherein the elongate body is provided with a pair of longitudinal rib means, extending therefrom remotely from the load contact face and defining said elongate slot means therebetween.

10. An impact absorbing device as claimed in any one of Claims] to 6, adapted for use with load back rest means comprising at least one elongate L-section member, the elongate body of the impact absorbing device being provided with a substantially flat back rest contact face mountable to an outer face of said L-section member.

11. An impact absorbing device as claimed in any one of the preceding claims, wherein the impact absorbing device is provided with fastening means to mount it to the load back rest means.

12. An impact absorbing device as claimed in Claim 11, wherein said fastening means comprises releasable fastening means.

13. A load back rest as herein defined provided with at least one impact absorbing device as claimed in any of the preceding claims.

14. A vehicle provided with a fork lift arrangement comprising a load back rest as claimed in Claim 13.

15. A method of producing a load back rest for a fork lift truck or the like comprising the steps of providing a load back rest comprising a plurality of elongate metal members, providing at least one impact absorbing device as claimed in any one of Claims 1 to 12 and mounting said at least one impact absorbing device to at least one said metal member.

16.An impact absorbing device substantially as described herein with reference to Figures 3 to 8 of the accompanying drawings.

17. A load back rest for a fork lift truck or the like substantially as described herein with reference to the Figures of the accompanying drawings.