IMPROVEMENTS IN OR RELATING TO FORKLIFTS

Abstract: A forklift (10) having a chassis (11) which is supported by an endless track (14), the forklift (10) further includes a movable member (15) movably mounted on the chassis (11) and having a pair of tynes (16) adapted to engage a load, and wherein said movable member (15) is positionable so that the load may be directly supported on the chassis (11).

Description: "IMPROVEMENTS IN OR RELATING TO FORKLIFTS" The present invention relates to forklifts and more particularly but not exclusively to forklifts having a track drive and which forklifts are adapted to be mounted on or towed by a truck. BACKGROUND ART It is a disadvantage of known forklifts that they ar not suitable for rough terrain such as building sites wherei they can frequently become bogged or encounter obstacles which they cannot overcome. It is a still further disadvantage that loads supported by conventional forklifts tend to make the vehicle unstable particularly on rough terrain, thus known forklifts are generally restricted to flat floor areas. Additionally, it is a further disadvantage of known forklifts that the total weight of the forklift and ' its load is not evenly distributed on a surface supporting the forklift. Accordingly conventional forklifts are excessivel heavy since they are required to carry excess weight to act as a counter balance to the load supported on the tynes of the forklift. The total weight of the above discussed forklifts, and their weight distribution will often cause damage to the surface over which the forklifts will pass. As for example, excessive weight will often crack and damage concrete driveways. It is an object of the present invention to overcome or substantially ameliorate the above disadvantages. DISCLOSURE OF INVENTION There is disclosed herein a forklift including a main frame; a pair of parallel transversely spaced longitudinally extending driven endless tracks movably supported on the frame and adapted to engage a ground surface to support the forklift; support means mounting said tracks on said main frame, each support means including a stabiliser bar extending longitudinally of the frame so as to be generally co-extensive with an associated one of said tracks, said bar being resiliently defor able and being supported on its OMPI extremities on said frame; a plurality of idler rollers rotatably mounted on said bar so as to be rotatable about axes extending transversely of the forklift, said rollers being positioned so as to engage a portion of the track engaged with said earth surface, and wherein said idler rollers are biased to engage said portion so as to distribut the weight of the forklift along the track. BRIEF- DESCRIPTION OF DRAWINGS A preferred form of the present invention will now b described by way of example with reference to the accompanying drawings, wherein: Figure 1 is a schematic perspective view of a forklift; Figures 2 and 3 are schematic perspective views of the forklift of Figure 1 with the tynes thereof in different positions; Figure 4 is a schematic side elevation of the track arrangement employed in the forklift of Figure 1; Figure 5 is a schematic side elevation of an alternative track arrangement to that of Figure 4; and Figure 6 is a schematic end elevation of the track arrangement of Figure 5. BEST MODE OF CARRYING OUT THE INVENTION The forklift 10 of Figure 1 is provided with a chassis 11 to which is rigidly fixed track supports 12 to which is rotatably mounted two pairs of rollers 13 around which pass tracks 14. Supported on the chassis 11 is a vertically extending member 15 which acts as a support for the tyne assembly 16. The member 15 is movably mounted on the chassis 11 so as to be movable from a forward position (as depicted in Figure 2) to a rear position (as depicted in Figure 3) . The tyne assembly 16 is also movable between a low position whereby a load is either received or delivered from the tynes to a raised position whereby the load is supported by the forklift 10. In operation of the forklift 10 of Figure 1, a load is first lifted by the forklift 10 when the tynes are in the forward position depicted in Figure 2. The load is subsequently raised and moved rearwardly and therefore the tynes are lowered so that a substantial part or the whole of the load is supported by the chassis 11. Now with particular reference to -Figure 4, the track n≠r 5 assembly 17 includes the supports 12 which rotatably support the rollers 13. Around the rollers 13 passes the track 14. In the present instance there is provided a plurality of upper idler rollers 18 which support the upper portion of th track 14 as it passes along the support 12. The lower 10 portion of the track 14 is supported by idler rollers 19 which in turn are attached to a stabiliser bar 20 extending between portions 21 of the support 12. One of the rollers, in this particular instance the roller 13A, is mounted so that its central axis is movable along the slot 22 to allow 15 the track 14 to deflect upwardly to the position 14A. In such an instance, the idler rollers 19 also move upwardly however the track 14 is biased to its lower position by mean of a suspension which engages the idler rollers 19. Such a suspension may be an air bag suspension which, by adjustment 20 of the pressure in the air bags, the load carried by various portions of the track 14 may be adjusted. In operation of the above track assembly 17, the forklift 10 is more adaptable to use in areas which would be sensitive to high loading. e.g. concrete driveways or 25 concrete slabs whereby it would be of a considerable disadvantage for the load to be concentrated on a very small area. In the present instance the entire load is spread along the two tracks 14 thus obviating concentration of the load. • 30 Turning now to Figures 5 and 6 wherein there is schematically illstrated an alternative means for mounting the stabiliser bar 20A on the track supports 12. One end of the stabiliser bar 20A is attached to a lever 22 which is pivotally attached to the support 12 by means of a pin or 35 axle 23. Preferably the bar 20A is also pivotally attached to the lever 22 by a pin 24. The lever 22 would be resiliently biased to a predetermined position on the support 12 so as to bias the end of the stabiliser bar 20A to which it is attached, to a predetermined position. However, upon the track 14 being deflected together with the rollers 19, the lever 22 would be forced to pivot as the stabiliser bar 20A is also deflected. The lever 22 is provided to enable one end of the stabiliser bar 20A to move relative to the support 12. "

Claims: CLAIMS 1. A forklift including a main frame; a pair of parallel transversely spaced longitudinally extending driven endless tracks movably supported on the frame and adapted to engage a ground surface to-support the forklift; support means mounting said tracks on said main frame, each support means including a stabiliser bar extending longitudinally of the frame so as to be generally co-extensive with an associated one of said tracks, said bar being resiliently deformable and being supported on its extremities, on said frame; a plurality of idler rollers rotatably mounted on sai bar so as to be rotatable about axes extending transversely of the forklift, said rollers being positioned so as to engage a portion of the track engaged with said earth surface, and wherein said idler rollers are biased to engage said portion so as to distribute the weight of the forklift along the track. 2. The forklift of claim 1 wherein each said bar is movably supported on one end of said frame to enable flexing of each bar. 3. The forklift of claim 2 wherein said one end of said bars is slidably supported on said frame. 4. The forklift of claim 2 wherein said one end of said bar is pivotally supported on said frame. 5. The forklift of claim 1 further including a sub-frame longitudinally movably provided on said main frame so as to be movable between a forward and a retracted position; a tyned arrangement mounted on said sub-frame so as to be movable therewith, said arrangement including at least one forwardly extending movable tyne adapted to engage and lift a load, and wherein said sub-frame, when at said retracted position enables the load to be supported directly on said main frame when said tyne or tynes is/are lowered. 6. A forklift substantially as hereinbefore described with reference to the accompanying drawings. -

Inventors: SOLOTAR ORION
Applicants: SOLOTAR ORION
Application year: 1982
Main classification: B62D55
IPC codes: B62D55, B66F9