WO1995032917A1

WO1995032917A1 - Load transport vehicles

Info

Publication number: WO1995032917A1
Application number: PCT/AU1995/000323
Authority: WO
Inventors: Neil James Senior
Original assignee: Pallet Boss Pty. Ltd.
Priority date: 1994-05-31
Filing date: 1995-05-31
Publication date: 1995-12-07

Abstract

A transport unit (200, 400, 500) is designed to be towed behind a prime mover (170) to enable loads (414, 507) to be transported from site to site, over even rough terrain. The load (e.g. containers, pallets, tanks) is engaged by forks (305, 406, 508) on a carrier frame (306, 407, 506), raised or lowered by a hydraulic ram (307, 410). The carrier frame (306, 407, 506) is mounted on a carriage (402) to enable the forks (305, 406, 508) to be extended rearwardly to load and unload the loads (414, 507) to and from the unit (200, 400, 500).

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.

In an effort to overcome the deficiencies of the prior art machines, we developed a load transport vehicle as disclosed in International Application No. PCT/AU93/00490 (= International Publication No. WO 94/06711). This unit enabled loads, eg. pallets, to be easily moved between sites, eg. over even rough terrain.

However, certain deficiencies of the vehicle became apparent:

(a) it could not load, or unload, the pallets, etc. onto, or from, other vehicles, eg. the prime mover or railway carriages;

(b) it could only load and unload pallets, etc. where there was clearance about three (3) sides of the pallet or load; and (c) the pallet or load was supported by the forks during transport, placing unwanted loads on the hydraulic system for the mast/forks. SUMMARY OF THE INVENTION

It is an object of the present invention to provide a forklift or pallet truck which overcomes some or all of the deficiencies of 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 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 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, conneσtable 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 loading and unloading position and a transport position; the load support means being mounted on substantially vertical guide or mast means or on parallel links or the like; and the guide or mast means being mounted on a carriage movably mounted on the frame, the carriage being movable from a transport position with the forks between the side frames and a loading/unloading position with the forks extending rearwardly of the side frames.

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 drawbar means, connectable to a prime mover, extending forwardly of the frame (and optionally hingedly connected thereto) ; at least one suspension unit (but preferably two or three such units) supporting the frame, each suspension unit having at least one ground engaging wheel; load support means, preferably with a pair of forks; lifting means on the frame to move the load support means between a loading and unloading position and a transport position; the load support means being mounted on substantially vertical guide or mast means or on parallel links or the like; and the •guide or mast means being mounted on a carriage movably mounted on the frame, the carriage being movable from a transport position with the forks over the frame and loading/unloading position with forks extending at least partially rearwardly of the frame.

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. 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:

FIG 1 is a rear view of a first embodiment of the forklift or pallet truck;

FIG 2 is a side view of a modified chassis of the unit;

FIG 3 is a rear view of a second embodiment of the forklift or pallet truck;

FIG 4 is a front view of the unit showing the forks in the loading/unloading positions; FIG 5 is a rear view of a third embodiment of the forklift or pallet truck;

FIG 6 is a side view of the chassis for the unit of FIG 5; and

FIGS 7 to 9 are schematic side views showing the mast and forks of the unit of FIGS 5 and 6 in the first loading/unloading position, the transport position, and the second loading/unloading position, respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS 25 and 26, the forklift or pallet truck, referred hereinafter as the transport unit 200, has a main frame or chassis 201 of substantially U-shape in plan view where the side frames 202, 203 are interconnected by the cross-members 204, 205. An A-frame drawbar of stepped design is welded to the chassis 201 and as shown in FIG 26 may be configured for fifth-wheel connection to the prime-mover.

Each side frame 202, 203 has a pair of suspension mount boxes 208 which receive pivot pins in transverse bushes at the forward end of the respective trailing arm assemblies 211. Box section trailing arms 112 have stub axles to receive wheels 214. Brackets 215 at the trailing ends of the arms 212 receive shackle pins (not shown) in the eyes of leaf springs 216 pivotally mounted on brackets 217 in the rear suspension mount box 207 on each side frame. The wheels 214 can move independently when they strike bumps or holes, but the load is shared between each pair of wheels 214 by the springs 216. Upper and lower guide channels 301, 302 are provided on each side frame 202, 203 and a substantially vertical mast 304 has pairs of rollers (not shown) received in the guide channels 301, 302 to enable the mast 304 to be maintained substantially vertically as it is moved between the side frames 202, 203 by a hydraulic ram (not shown). Load forks 305 are mounted on a lift carriage 306 guided by the mast 304 and raised and lowered by a hydraulic ram 307.

The operation of the rams for the carriage and the forks 305 is controlled by control valves 308 connected to a power-pack 309.

While it is preferred that the rack 30 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.

To stabilise the unit 300, load jacks (not shown) may be provided at or adjacent the rear ends of the side frames 202, 203.

To unload, eg. a railway wagon, the unit 200 is placed adjacent the wagon and the load jacks are extended.

The forks 305 are raised on the mast 303 by ram 307, and then the mast 303 is moved along the guides 301, 302 until the forks 305 engage the pallet. The mast 303 is then moved to retract the forks between the side frames 202, 203 and the mast then lowers the forks between the side frames 202, 203. The lifting jacks are raised.

The load can now be transported from the goods yard to the consignees.

At the consignee's site, the pallet may be unloaded by reversing the procedure - for placement on raised supports, or may be placed on the ground by further lowering the forks to a secondary loading/ unloading position. (The forks can be extended rearwardly, if desired, eg. to place the pallet in a confined space.)

With this unit, the need for a forklift is avoided as the unit acts as its own forklift for unloading from, or loading onto, eg. a truck, railway wagon or the like without affecting its ability to transport the load from site to site.

"Interlock" means may be provided in the control valve 308 to prevent the forks being extended from the rear of the unit and/or raised to the loading/unloading position except when the lifting jacks are extended to stabilise the unit.

The forks 305 on the load platform can be used to engage industrial containers, pallets for bricks, livestock crates, insulated containers, spray tanks, portable buildings (eg. site offices or toilets) or the like.

The mast 304 may be mounted on parallel links to allow the forks 305 to be extended and retracted as an alternative to the carriage and guides 201, 202.

Referring now to FIGS 27 and 28, the unit 400 is a modified version of the unit 200 of FIGS 25 and 26.

The mast 401 has a pair of carriages 402 with rollers (not shown) engaged in upper and lower guide channels 403, 404 to enable the mast 401 to be maintained substantially vertical as it is moved from the transport position in FIG 27 to the loading/ unloading positions in FIG 28. The movement of the mast

401 is controlled by a ram having a piston rod 405. The lift forks 406 are mounted in a lift carriage 407 on the mast 401, the lift carriages 407 being raised and lowered by a lift ram 408 and lift chains 409 assembly. The lift ram 408 is supplied with hydraulic fluid via a spring tensioned hydraulic line 410. •

The operation of this unit is substantially as hereinbefore described for the unit 200 of FIGS 25 and 26.

A strap 411 (eg. of polypropylene) is wound onto a drum 412 mounted on one side frame of the unit 400 and is engageable with an anchor 413 on the other side frame. During transport, the strap 411 can be passed under the forks 406 to assist the lift ram 410, or can pass over the load 414 to assist in securing the load 414 to the forks 406.

One or more removable bars 415, releasably anchored on the lower guide channels 404, can be used to assist in supporting the forks 406 in the transport position. In all of the embodiments described and illustrated hereinbefore, the units have substantially U-shaped chasses which straddle the loads. Referring now to FIGS 29 and 30, the unit 500 has a chassis 501 supported on a pair of transverse axles 502, which underlie a deck or tray 503.

The axles 502 are located by trailing arms 504 hingedly mounted on the chassis 501 and are interconnected by load-sharing springs 505.

The operation of the unit 500 is generally similar to that of units 200 and 400 in that the mast

506 is moveable along the chassis 501 from the transport position (dashed lines in FIG 30) to the loading/ unloading positions (solid lines in FIG 30).

In the transport position (shown in FIG 29), the load (eg. a pallet) 507 is lowered onto the deck 503 so that its weight is not carried by the forks 508.

As with the units 200 and 400, hydraulic rams (or manual screw jacks) 509 can be lowered to support the rear of the chassis 501 when the mast 506 is moved rearwardly from the transport position.

FIGS 31 and 33 show the low and high loading/ unloading positions for the load 507 using unit 500, and FIG 32 shows the transport position therefor.

As will be readily apparent to the skilled addressee, the deck 503 can be fitted to the units 200 and 400 in the space between the respective side frames thereof.

In the units illustrated, the wheels are provided on stub axles or transverse axles connected to the chassis or frame by trailing arms. It will be readily apparent to the skilled addressee that where two or more transverse axles are used, eg. as in unit 500, the axles 502 can be interconnected by leaf springs/rocker arm assemblies or like load sharing suspensions as found on load transport vehicles. It will be further readily apparent to the skilled addressee that the guides/mast/fork assemblies of the units 400 and 500 could be fitted to existing trailers, where the floor therein provides the "deck or try 503". In an alternative embodiment (not shown), the forks 406, 508 may be replaced by a single pole or spike eg, to enable carpet rolls to be transported.

In another alternative embodiment, the forks may be replaced by a jib or beam with a hook from which a load may be suspended.

Various changes and modifications may be made to the embodiments described and illustrated without departing from the present invention.

Claims

1. 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, 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 loading and unloading position and a transport position; the load support means being mounted on substantially vertical guide or mast means or on parallel links or the like; and the guide or mast means being mounted on a carriage movably mounted on the frame, the carriage being movable from a transport position with the forks between the side frames and a loading/unloading position with the forks extending rearwardly of the side frames.

2. A forklift or pallet truck as claimed in claim

1 wherein: the load support means is moved between a raised, loading and unloading position and a lowered, transport position.

3. A forklift or pallet truck as claimed in Claim

2 wherein: the load support means can be lowered to a secondary loading and unloading position.

4. A forklift or pallet truck including: a frame; a drawbar means, connectable to a prime mover, extending forwardly of the frame (and optionally hingedly connected thereto) ; at least one suspension unit (but preferably two or three such units) supporting the frame, each suspension unit having at least one ground engaging wheel; load support means, preferably with a pair of forks; lifting means on the frame to move the load support means between a loading and unloading position and a transport position; the load support means being mounted on. substantially vertical guide or mast means or on parallel links or the like; and the guide or mast means being mounted on a carriage movably mounted on the frame, the carriage being movable from a transport position with the forks over the frame and loading/unloading position with forks extending at least partially rearwardly of the frame.

5. A forklift or pallet truck as claimed in Claim

4 wherein: the frame has a deck, tray, platform, guides, locks or the like to support the load when the forks are in the transport position.

6. A forklift or pallet truck as claimed in Claim

5 wherein: the forks are raised, when in the loading and unloading position, and can be lowered, rearwardly and below the level of the tray, deck, etc., in that position.

7. A forklift or pallet truck as claimed in Claim 1 wherein: 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.

8. A forklift or pallet truck as claimed in Claim 4 wherein: 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.

9. A forklift or pallet truck as claimed in Claim 1 wherein: the carriage includes rollers on the mast means, movable in guides along the side frames, the carriage being moved by hydraulic rams or jacks, cables and winches, or the like.

10. A forklift or pallet truck as claimed in Claim 4 wherein: the carriage includes rollers on the mast means, movable in guides along the side frames, the carriage being moved by hydraulic rams or jacks, cables and winches, or the like.

11. A forklift or pallet truck as claimed in Claim 1 wherein: the suspension unit comprises trailing (or leading) suspension arms pivotally mounted on respective side frames and having stub axles for the respective ground wheels.

12. A forklift or pallet truck as claimed in Claim 4 wherein: the suspension unit comprises trailing (or leading) suspension arms pivotally mounted on respective side frames and having stub axles for the respective ground wheels.

13. A forklift or pallet truck as claimed in Claim 4 wherein: the suspension unit(s) comprises axles extending across (preferably below) the deck, tray, etc., and provided with wheel(s) at each end thereof.

14. A forklift or pallet truck as claimed in Claim 1 wherein: the suspension units on each side frame, or on each side of the frame, are interconnected for load- sharing by leaf springs or rocker arms, or are provided with coil springs, leaf springs, dampers, air suspension bags or the like.

15. A forklift or pallet truck as claimed in Claim 4 wherein: the suspension units on each side frame, or on each side of the frame, are interconnected for loadr sharing by leaf springs or rocker arms, or are provided with coil springs, leaf springs, dampers, air suspension bags or the like.