WO1994006711A1

WO1994006711A1 - Load transport vehicles

Info

Publication number: WO1994006711A1
Application number: PCT/AU1993/000490
Authority: WO
Inventors: Neil James Senior
Original assignee: Pallet Boss Pty. Ltd.
Priority date: 1992-09-23
Filing date: 1993-09-22
Publication date: 1994-03-31
Also published as: EP0662068A1; NZ255975A; EP0662068A4; JPH08501051A

Abstract

A transport unit (100) is designed to be towed behind a prime mover (170) to enable loads to be transported from site to site, over even rough terrain. The unit (100) has wheels (114) journalled on axles (113) on trailing arms (112) provided with springs (116) (or rocker arms) to share the load. The load (e.g. containers, pallets, tanks) is engaged by forks (125) on a carrier frame (124), raised or lowered by a hydraulic ram. As the unit (100) straddles the load with its U-shaped chassis, and the load may be transported at a low height, the unit (100) is very stable. Lights (16), mud flaps (161), brakes and the like enable the unit (100) to be towed on public roads.

Description

TITLE: "LOAD TRANSPORT VEHICLES"

BACKGROUND OF THE INVENTION

1. Field of the Invention

THIS INVENTION relates to improvements in load transport vehicles, including forklifts. (The term "forklifts" shall also include stacker trucks, pallet trucks and like transport vehicles.)

2. Prior Art

There are many small businessmen who have the requirement for a small forklift (eg. in 0.5-4.9 tonne range) who cannot justify the expense of a small motorised forklift truck, but whose loads are too large or cumbersome for a walking lift truck or stacker.

With the walking lift trucks, only a very small load can be transported and the small wheels mean that they can only be used successfully on smooth floors, ie. they are not suitable for outside use.

The motorised forklift trucks are expensive to purchase, even second-hand, and have unwanted maintenance costs.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a forklift unit which fills the gap between the existing machines. It is a preferred object to provide a forklift unit which can be connected to a small vehicle as the prime mover for the forklift unit.

It is a further preferred object to provide a unit which can be easily wheeled away and stored when not in use.

It is a further preferred object to provide a unit which can transport loads from site to site, even over rough terrain.

Other preferred objects of the present invention will become apparent from the following description.

In one aspect, the present invention resides in a transport unit of the type having: a substantially vertical mast; a load support means, with a pair of load engaging forks, mounted for vertical movement on the mast; and lifting means to raise and lower the load support means on the mast; wherein: the mast is mounted on a frame, the frame including: a pair of spaced, substantially parallel legs extending to the same side of the mast as the forks; ground engaging wheels at or adjacent the distal ends of the legs; and a drawbar means, having a coupling releasably connectable to a prime mover, extending to the opposite side of the mast. The ground engaging wheels, optionally two per leg, may be provided with suspension means. Each wheel may be rotatably mounted on an axle at the distal end of a trailing (or leading) suspension arm and the suspension arms along each leg may be provided with suitable springs (eg. coil or leave springs) or air suspension units and may be interconnected, eg. by rocker arms.

Preferably, a retractable jockey wheel is provided on the drawbar to support the drawbar when the latter is not connected to a prime mover.

Preferably, the lifting means incorporates a power unit for a hydraulic ram which raises and lowers the load support means on the mast, the power unit preferably including at least one storage battery, an electric motor and a hydraulic pump. Preferably, the power unit (and ram) is controlled by a control unit which has a cable of a length to enable the unit to be controlled from the driver's seat of the prime mover. In a second aspect, the present invention resides in a pallet truck including: a frame; a load support means, preferably with a pair of load engaging forks, mounted on at least two pairs of parallel links for vertical movement relative to the frame; lifting means to raise and lower the load support means; a pair of spaced, substantially parallel legs extending to the same side of the frame as the forks; ground engaging wheels at or adjacent the distal ends of the legs; and a drawbar means, having a coupling releasably connectable to a prime mover, extending to the opposite side of the frame; so arranged that the lifting means is operable to move the forks between a lowered, pallet loading and unloading position, and a raised pallet transport position.

In an alternative embodiment, the load support means may be provided with rollers engageable in substantially vertical mast guides.

The ground engaging wheels, optionally two per leg, may be provided with suspension means. Each wheel may be rotatably mounted on a hub at the distal end of a trailing (or leading) suspension arm and the suspension arms along each leg may be provided with suitable springs (eg. coil or leave springs) or air suspension units and may be interconnected, eg. by rocker arms. The lifting means may include a hydraulic ram or jack; a cable-and-winch; or other suitable lifting means to raise and lower the forks relative to the frame. In a third aspect, the present invention resides in a pallet truck including: a frame; a load support means, preferably with a pair of load engaging forks, mounted on the frame; a pair of spaced, substantially parallel legs extending to the same side of the frame as the forks; ground engaging wheels at or adjacent the distal ends of the legs; a drawbar means, having a coupling releasably connectable to a prime mover, extending to the opposite side of the frame; so arranged that the wheels are mounted for substantially vertical movement relative to the legs; and lifting means are connected to the wheels to move the forks between a lowered, pallet loading and unloading position, and a raised pallet transport position. In a modified embodiment, each leg may have two or more wheels interconnected to move in unison to maintain the legs substantially parallel to the floor as the forks are raised and lowered, and the drawbar is hingedly connected to the frame. The wheels may have axles mounted on bell- cranks hingedly mounted on the legs, and the lifting means may comprise at least one hydraulic ram on the frame connected to the bell-cranks by suitable links.

The ground engaging wheels, optionally two per leg, may be provided with suspension means. Each wheel may be rotatably mounted on a hub at the distal end of a trailing (or leading) suspension arm and the suspension arms along each leg may be provided with suitable springs (eg. coil or leave springs) or air suspension units and may be interconnected, eg. by rocker arms.

In a fourth embodiment, the present invention resides in a forklift or pallet truck including: a substantially U-shaped frame having a transverse cross-member or sub-frame at the front and a pair of side frames extending rearwardly therefrom; a drawbar means, having a coupling releasably connectable to a prime mover, extending forwardly from the front sub-frame or transverse cross- member (and optionally hingedly connected thereto); at least one suspension unit (but preferably two or three such units) hingedly mounted on each side frame, each suspension unit having a respective ground engaging wheel; load support means, preferably with a pair of load engaging forks, lifting means on the frame to move the load support means between a lowered, loading and unloading position and a raised, transport position; the load support means being mounted on substantially vertical guide or mast means or on parallel links or the like.

The lifting means may include a hydraulic ram or jack; a cable-and-winch; or other suitable lifting means to raise and lower the forks relative to the frame. The suspension units may comprise trailing (or leading) suspension arms pivotally mounted on respective side frames and having stub axles for the respective ground wheels. The suspension units on each side frame may be interconnected by load sharing by, eg. leaf springs or rocker arms, and may be provided with coil springs, leaf springs, dampers, air suspension bags or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

To enable the invention to be fully understood, preferred embodiments will now be described with reference to the accompanying drawings, in which:

FIGS 1 and 2 are respective rear and front views of a forklift unit;

FIG 3 is a plan view of a first embodiment of a pallet truck;

FIGS 4 and 5 are side views of the pallet truck with the forks in the lowered and raised positions, respectively;

FIGS 6 and 7 are side views of a second embodiment of a pallet truck in the lowered and raised positions, respectively;

FIG 8 is a rear perspective view of a further embodiment of a forklift or pallet truck which may be used over rough terrain; FIGS 9 and 10 are respective plan and side views of a forklift or pallet truck, with FIG 10A being a section on line A-A on FIG 10;

FIGS 11 and 11A are respective plan and side views, in more detail, of the chassis and FIG 12 is a sectional view on line A-A of FIG 11;

FIGS 13 and 14 are plan and side views of a trailing arm for the suspension, and FIGS 15 and 16 are views A and B on FIG 13;

FIG 17 is a front view of the roller frame on the chassis;

FIG 18 is a side view of the roller frame and forks assembly; and

FIGS 19 to 24 are respective rear perspective views showing alternative applications for the forklift or pallet truck of FIG 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS 1 and 2, the forklift unit 10, which may have a load capacity of 0.5-4.9 tonnes, has a mast 11 which guides and supports a load support unit 12, with parallel load engaging forks 13. The load support unit 12 is raised and lowered via a hydraulic ram 14 operating on chains 15 anchored on a cross-bar 16 on the mast 11 and on the load support unit 12. This constructional arrangement is conventional. The unit 10 has a frame 20 with a main cross- member 21 on which the mast 11 is mounted. A pair of spaced, parallel legs 22, 23 extend from the ends of the cross-member 21 to the same side of the mast 11 as the forks 13, the spacing allowing the forks 13 to be lowered between the legs 22, 23 to engage and lift a pallet (not shown). Each leg 22, 23 has a ground wheel 24, 25 at its distal end.

An A-frame type drawbar 26 extends from the cross-member 21, to the opposite side of the mast 11 to the forks 13, and has convergent arms 27, 28 of modified Z-shape in side view. A tow-ball coupling 29 is provided at the apex of the drawbar 26 to enable releasable coupling of the unit 10 to a prime mover (not shown) . A retractable jockey wheel assembly 30 is provided on the drawbar 26 adjacent the coupling 29.

A housing 31 contains the power unit for the hydraulic ram 14, the power unit comprising at least one storage battery, an electric motor, a hydraulic pump and a hydraulic oil tank. The operation of the power unit, and tV.reby the ram 14, is controlled by a control unit 32, having a cable 33 of a length sufficient to enable the forklift unit 10 to be controlled by an operator in the prime mover. A U-shaped handle 34 enables the unit 10 to be wheeled around when disconnected from the prime mover.

The prime mover 170 is preferably a small utility, truck or 4-wheel drive (4WD) unit, eg. with a load capacity of 0.5-2.0 tonnes of the type commonly owned by small businessmen (see FIG 8, 19-24). It is preferred that the prime mover has a towball (to be connected to the coupling) mounted at the front of the prime mover and that it be offset to be aligned with the operator. This enables the operator to more easily control the forklift unit and engage the pallets with the forks 13. In use, the unit 10 is coupled to the prime mover and the operator uses the prime mover to move the unit, eg. to pick up a pallet from a delivery vehicle, manoeuvre the unit to a storage area and lower the pallet for unpacking. As the prime mover provides the motive power for the unit 10, it can move the unit over uneven surfaces with loads which would not be possible with a walking forklift.

When the forklift unit 10 is not required, the jockey wheel assembly 30 is lowered and the coupling 29 released from the towball on the prime mover. By use of the handle 34, the unit 10 may be wheeled to a storage area until it is next required.

With even a small prime mover, loads up to 4.9 tonnes may be handled, although loads in the range of 0.5-1.25 (or 1.5) tonnes are preferred.

As the small businessman usually already owns (or leases) a small truck or the like, he is not paying for an additional/unnecessary motive power unit for the forklift unit (compared with a conventional forklift truck) . This clearly reduces his purchase and operating costs.

While the present unit may not be as flexible or manoeuvreable as a conventional forklift truck, the owner could soon develop a high level of skill which would substantially overcome these disadvantages while enjoying the cost benefits discussed.

In an alternative embodiment, the mast 11, load support assembly 12 and ram 14 may be substituted by the equivalent components in a load stacker unit, while in a third embodiment, the invention is adaptable to a pallet truck.

Referring now to FIGS 3 to 5, a pallet truck

50 has a U-shaped frame 51, with a cross member 52 and spaced parallel legs 53, 54. An A-frame drawbar 55 extends from the opposite side of the cross-member 52 to the legs 53, 54 and has a tow-ball coupling 56.

A pair of pallet engaging forks 57, 58 each have vertical legs 59, 60 mounted for substantially vertical movement, relative to the frame 51, via pairs of upper and lower parallel links 61, 62 pivotally mounted on vertical support posts 63, 64 on the cross member 52.

A hydraulic ram 65 has its cylinder 66 mounted (via brackets 67) on the cross-member 56 and its piston rod 68 connected to a cross-bar 69 interconnecting the upper parallel links 61.

The legs 53, 54 are supported on ground wheels 70. As shown in FIG 4, the ram 65 is operated to lower the forks 57, 58 to enable a pallet to be engaged (or disengaged) when received between the legs 53, 54 When the ram 65 is extended, the forks 57, 58 are raised and the pallet can be transported to the desired location.

In the pallet truck 80 of FIGS 6 and 7, the forks 81 are fixed to the cross-member 82 of the frame 83, the latter having a drawbar 84 and coupling 85.

Each leg 86 has a substantially retractable ground wheel 87 with its axle on a bell-crank 88 pivotally mounted within the leg 86. A link 89 is connected to a lever 90 connected to a cross-shaft 91. A ram 92 has its cylinder 93 mounted on a vertical post 94 centrally of the cross-member 82 and its piston rod 95 connected to a lever 96 at the centre of the cross- shaft 91. As the ram 92 is extended, the wheels 87 are extended to move the forks 81 from a loading and unloading position (FIG 6) to a transport position (FIG 7). In a modified embodiment not shown, each leg

86 may have a pair of retractable wheels 87 linked together, and the drawbar 84 may be hinged to the cross- member 82 so that the legs 86 (and forks 81) may be raised and lowered in parallelism to the floor. As an alternative to the hydraulic ram 92, a rotary actuator could be connected to one end of the cross-shaft 91, or it could be rotated by, eg. an electric motor and gears/chain and sprockets.

In the embodiment of FIGS 3 to 5, a winch could be mounted on the cross-member 52 or drawbar 55 and a cable pass over a pulley on a central post and be connected to the cross-bar 69 to raise and lower the forks 57, 58.

The rams 65, 92 (or the alternatives thereto) will again be remotely controlled as hereinbefore described for the forklift of FIGS 1 and 2.

Referring to FIGS 8 to 12, the forklift or pallet truck, referred hereinafter as the transport unit 100, has a main frame or chassis 101 of substantially U- shape in plan view (see FIGS 9 and 11) where the side frames 102, 103 are interconnected by cross-members 104, 105. An A-frame drawbar 106 of stepped design is welded to the chassis 101 and has links 107 welded to the lower end of the roller frame 120 to be hereinafter described. Each side frame 102, 103 has a pair of suspension mount boxes 108 which receive pivot pins 109 in transverse bushes 110 at the forward end of respective trailing arm assemblies 111 (see FIGS 10, 13- 16). Box section trailing arms 112 have stub axles 113 to receive wheels 114. Brackets 115 at the trailing ends of the arms 112 receive shackle pins (not shown) in the eyes of leaf springs 116 pivotally mounted on brackets 117 in the rear suspension mount box 108 on each side frame. The wheels 114 can move independently when they strike bumps or holes, but the load is shared between each pair of wheels 114 by the springs 116.

A roller frame 120 (see FIGS 9, 10, 10A, 17, 18) is welded to the cross member 105 and has two pairs of spaced, vertically aligned rollers 121 journalled on axles 122. The rollers 121 are received in vertical C- section mast guides 123 welded to a carriage frame 124 which has a pair of rearwardly extending forks 125 (on a load platform). A hydraulic ram (not shown), mounted on the cross member 105, or the head rail of the roller frame, has its ram (or cylinder) connected to the carriage frame 124 to selectively raise or lower the forks 125. The ram is powered by a self-contained power unit (not shown) mounted on the drawbar 106 and can be remotely controlled from the tow vehicle as hereinbefore described.

The forks 125 on the load platform can be used to engage industrial containers 150, pallets for bricks 151, livestock crates 152, insulated containers 153, spray tanks 154, portable buildings 155 (eg. site offices or toilets) or the like (see FIGS 19 to 24).

As the unit 100 has road going suspension (and can be fitted with lights 160, brakes, number plates, mudflaps 161 and other road going equipment) , it can be used to transport loads from one site to another, even over rough ground. A particularly suitable application is the transport of loads off-road by the military, while even the smallest trader can transport goods, eg. from his wholesaler to his retail outlet.

In a modified embodiment (not shown), and particularly for rough terrain, the pivot pins 109 and the pivotal axis for the springs 116 can be interconnected and selectively raised or lowered to provide high ground clearance.

The carriage frame 124 may be mounted on parallel links as shown in FIGS 4 and 5 to allow the forks 125 to be raised and lowered.

While it is preferred that the power unit for the hydraulic ram, or other lifting means, to be battery-powered, the pump for the ram or other lifting means may be manually powered and/or operated.

Various changes and modifications may be made to the embodiments described and illustrated without departing from the scope of the present invention defined in the appended claims.

Claims

1. A transport unit of the type having: a substantially vertical mast; a load support means, with a pair of load engaging forks, mounted for vertical movement on the mast; and lifting means to raise and lower the load support means on the mast; wherein: the mast is mounted on a frame, the frame including: a pair of spaced, substantially parallel legs extending to the same side of the mast as the forks; ground engaging wheels at or adjacent the distal ends of the legs; and a drawbar means, having a coupling releasably connectable to a prime mover, extending to the opposite side of the mast.

2. A unit as claimed in Claim 1 wherein: each ground engaging wheel is provided with suspension means.

3. A unit as claimed in Claim 2 wherein: each ground engaging wheel is rotatably mounted on an axle at a distal end of a trailing or leading suspension arm pivotally mounted on a leg of the frame; and springs or air suspension units interconnect each suspension arm to the leg of the frame; and two or more suspension arms along each leg are (optionally) interconnected to share a load supported by the transport unit.

4. A unit as claimed in any one of Claims 1 to 3 wherein: a retractable jockey wheel is provided on the drawbar means to support the drawbar means when the coupling is not connected to the prime mover.

5. A unit as claimed in any one of Claims 1 to 4 wherein: the lifting means incorporates a power unit for a lifting ram which raises or lowers the load support means on the mast, the power unit (optionally) including at least one storage battery, an electric motor and a hydraulic pump.

6. A unit as claimed in Claim 5 wherein: a power unit is controlled by a control unit operable from the prime mover.

7. A pallet truck including: a frame; a load support means, (optionally) with a pair of load engaging forks, mounted on at least two pairs of parallel links for vertical movement relative to the frame; lifting means to raise and lower the load support means; a pair of spaced, substantially parallel legs extending to the same side of the frame as the forks; ground engaging wheels at or adjacent the distal ends of the legs; and a drawbar means, having a coupling releasably connectable to a prime mover, extending to the opposite side of the frame; so arranged that the lifting means is operable to move the forks between a lowered pallet loading and unloading position, and a raised pallet transport position.

8. A pallet truck as claimed in Claim 7 wherein: each ground engaging wheel is provided with suspension means.

9. A pallet truck as claimed in Claim 8 wherein: each ground engaging wheel is rotatably mounted on an axle at a distal end of a trailing or leading suspension arm pivotally mounted on a leg of the frame; and springs or air suspension units interconnect each suspension arm to the leg of the frame; and two or more suspension arms along each leg are (optionally) interconnected to share a load supported by the transport unit.

10. A pallet truck including: a frame; a load support means, preferably with a pair of load engaging forks, mounted on the frame; a pair of spaced, substantially parallel legs extending to the same side of the frame as the forks; ground engaging wheels at or adjacent the distal ends of the legs; a drawbar means, having a coupling releasably connectable to a prime mover, extending to the opposite side of the frame; so arranged that the wheels are mounted for substantially vertical movement relative to the legs; and lifting means are connected to the wheels to move the forks between a lowered, pallet loading and unloading position, and a raised pallet transport position.

11. A pallet truck as claimed in Claim 10 wherein: each leg has two or more suspension units interconnected to move in unison so as to maintain the legs substantially parallel to the floor as the forks are raised or lowered; and the drawbar means is hingedly connected to the frame.

12. A pallet truck as claimed in Claim 11 wherein: the wheels have axles mounted on bell cranks hingedly mounted on the legs; and the lifting means comprises at least one hydraulic ram on the frame connected to the bell cranks by links.

13. A pallet truck as claimed in any one of Claims 10 to 12 wherein: each ground engaging wheel is provided with suspension means.

14. A pallet truck as claimed in Claim 13 wherein: each ground engaging wheel is rotatably mounted on an axle at a distal end of a trailing or leading suspension arm pivotally mounted on a leg of the frame; and springs or air suspension units interconnect each suspension arm to the leg of the frame; and two or more suspension arms along each leg are (optionally) interconnected to share a load supported by the transport unit.

15. A forklift or pallet truck including: a substantially U-shaped frame having a transverse cross-member or sub-frame at the front and a pair of side frames extending rearwardly therefrom; a drawbar means, having a coupling releasably connectable to a prime mover, extending forwardly from the front sub-frame or transverse cross- member (and optionally hingedly connected thereto); at least one suspension unit (but optionally two or three such units) hingedly mounted on each side frame, each suspension unit having a respective ground engaging wheel; load support means, (optionally) with a pair of load engaging forks, lifting means on the frame to move the load support means between a lowered, loading and unloading position and a raised, transport position; the load support means being mounted on substantially vertical guide or mast means or on parallel links or the like.

16. A forklift or pallet truck including: a each suspension unit comprises a trailing or leading arm pivotally mounted on one side frame and having a stub axle for a wheel; and the suspension units on each side frame are interconnected for load sharing by leaf springs or rocker arms.

17. A forklift or pallet truck as claimed in Claim 16 wherein: each suspension arm is provided with a coil spring, leaf spring, damper and/or air suspension bag.