TITLE: VEHICLE MOUNTED LIFTING DEVICE

FIELD OF THE INVENTION

This invention concerns lifting devices for mounting on flat bed vehicles, namely flat bed trucks and utes.

BACKGROUND OF THE INVENTION

Drivers wishing to cany loads such as washing machines, refrigerators, furniture,

photocopiers, gas cylinders, drums, machinery, crates of produce, hay bales and the like often try to use a low loading trailer or rent a vehicle with a hydraulic platform. There is a risk of back injury to drivers handling such jobs and the legislation now limits the permissible load to 25kg/person. This raises costs for many businesses because one-off loads do not justify the costs of a vehicle fitted with a hydraulic platform.

SUMMARY OF THE INVENTION

The apparatus aspect of the invention provides a lifting device which is mountable on the rear of a flat bed vehicle comprising an upright mast with a foot capable of engaging the ground as a reaction surface and a load-supporting part which slews between a position which registers with the flat bed and a position at ground level.

The load supporting part may be a carriage which rises and falls on the mast between an ON load /OFF load position on the ground and a slew position somewhat higher than the flat bed.

The carriage may have a socket for reception of a crane jib or a horizontal spike for impaling a hay bale.

The carriage may instead have a pair of forks like a conventional forklift. The carriage may have sets of wheels which engage the front and rear faces of the mast so as to provide a low friction upright passage with minimum lost motion. An electric winch is a convenient unit for raising and lowering a carriage carrying loads of up to 600kg or whatever is the carrying capacity of the flat bed vehicle. Such motors are already used on 4WD vehicles as winches using the vehicles 12v, 150A battery power. The winch may be fixed at or near the top of the mast above the carriage.

The ground engaging foot may be carried by a mast extension. The extension may be a telescopic leg which operates like a screw jack. The jack may be operated by hand or by a cordless drill acting as a driver.

The mast may have a bracket which engages the tow bar of the vehicle and optionally a bed bracket which engages the flat bed. This arrangement allows the foot to be parked clear of the ground. Although one of the brackets transfers the lifted loads to the vehicle, the vehicle suspension is not compressed because the foot transfers into the ground the downward force on the mast. The tow bar bracket may offer a range of positions to suit trucks and utes of different heights.

The mast may be made of an upper part and a lower part, the upper part being free to slew. An upright pin support in bearings in both upper and lower parts allows slewing on the mating ends of the mast. A slewing motion opposed by some friction is preferred so as to require deliberate force to initiate slewing otherwise accidental load displacement may occur. A tilted vehicle position could allow sudden, unintended slewing.

Generally therefore if a load such as a filing cabinet is on a pallet sitting on the ground awaiting removal, the driver raises the foot using the j ack and reverses the carriage forks beneath the pallet. The driver drops the foot by screwing the jack in the opposite direction until it touches the ground. The winch is plugged into a socket served by the vehicle wiring harness and the winch raises the cabinet until the forks are at slewing height, namely 20mm higher than the flat bed. The carriage is slewed manually through 180° so that the carriage overlies the flat bed. The winch lowers the pallet and cabinet onto the flat bed and the driver secures it with ties and raises the foot before driving off.

The process is reversed when the cabinet is off-loaded.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention is now described with reference to the accompanying drawings, in which:

Figure 1 is a perspective of the device.

Figure 2 is a front view of the device.

Figure 3 is a side view of the device.

Figure 4 is a plan on a smaller scale.

Figure 5 is a perspective on a smaller scale of the lower mast.

Figure 6 is a rear view of a fragment of the mast showing another version of the carriage.

Figure 7 is a perspective view of the carriage.

DETAILED DESCRIPTION WITH RESPECT TO THE DRAWINGS

Referring nowto the drawings, a lower mast 2 made of square steel tube 730mm long has a telescopic square steel tube extension 4 which slides inside the lower mast and ends in a rectangular foot 6. A screw jack (not shown) lies coaxially inside the mast and extension and operates to adjust the height of the foot above the road or ground. The jack is rotated by bevel gears and a nut (not shown) in known manner and the horizontal gear is drivable through a hexagon head 8 projecting from the side of the mast 2. Mast 2 has a vertical fin 10 with a row of holes 12.

Bracket 14 is securable to the fin by bolts 16 at a suitable height and pad 18 is adjustable fore and aft to register with the tow bar 20 ( Figure 3) of a flat bed utility vehicle. While this assembly secures the lower mast 2 to the tow bar, assembly 22 additionally secures the lower mast to the flat bed 24 (Figure 3) of the vehicle.

The assembly 22 consists of a lug 26 welded to the lower mast 2 and an L-section plate 28 fastened to lug 26 by a bolt clamped in slot 30 (Figure 5). Plate 28 has six holes 32 for the reception of fasteners. This assembly need only be somewhat adjustable via slot 30 because most of the adjustment is made at fin 10.

In Figure 3 there is a further plate 34 underlying plate 28 and downwardly extending bracket 36.

Referring now to Figure 5, the top of the lower mast 2 has a pair of horizontal pins 40 which pass through the support post 42 (Figure 5). Post 42 occupies most of the square space inside the tube and extends above the end of the lower mast by 100mm. The lower end of upper mast 44 engages post 42 and is free to rotate about a vertical axis.

Upper mast 44 is about 1100mm in length and is closed by a cap 46. Just below the cap is a mount 48 for an electric winch 50 powered by the vehicle battery. The winch cable 52 is secured to the mast and forms a loop 54. Carriage 56 is of channel section (6mm plate) with a front face 58 and sides 60. An upper pair of wheels 62, 64 and a lower pair of wheels 66, 68 contact the front and rear faces of the upper mast in order to ensure that the carriage rises and falls smoothly and cannot be displaced. The carriage 56 is capable of descending to the bottom of the lower mast 2.

Rails 70, 71 extend horizontally from the carriage and support vertical stiles 72 and horizontal forks 74. Each vertical stile 72 has a sleeve portion 73 at its top end. The sleeve portions 73 support the vertical stiles on rail 70. They also allow the vertical stiles to be slid on the rail 70 so that the forks 74 may be adjusted closer together or further apart as required by the configuration of the pallet or load. Carriage 56 has a pulley 76 which lies in loop 54. The front face 58 of the carriage has a socket 78 which supports crane jib 80 (Figures 3 and 7) which has a series of spines 81. A guide 83 is adapted to sit in the gaps between the guides, allowing a chain and snap hook 82 to be adjustably hung from the jib 80. Alternatively the socket supports a bale piercing spike 84 (Figure 3).

The winch is connectable to the wiring harness of the vehicle to take 150A (cranking current). An I-r remote control operates a switch (not shown) so that the driver can stand clear of the device and observe the position of the load. The crane hook 80 is useful for loads which may suit a sling.

Loads of up to one tonne can be hoisted which matches the load capacity of the vehicle.

In Figure 6 the carriage is modified by bending the sides 60 outwardly to form a radiussed

flange 84. If the carriage is not raised to the correct height for slewing, such as may occur when there is insufficient light to see what is happening, the radiussed flange will strike the top of the mast 2 and tend to lift the carriage to allow it to slew. Post 42 extends 250mm into the upper mast 44.

We have found the advantages of the above embodiment to be:

1. Simplicity of construction utilising an electric winch of proven capacity and reliability.

2. The adaptation to act as a forklift, crane and bale carrier.

It is to be understood that the word "comprising" as used throughout the specification is to be interpreted in its inclusive form, ie. use of the word "comprising" does not exclude the addition of other elements.

It is to be understood that various modifications of and/or additions to the invention can be made without departing from the basic nature of the invention. These modifications and/or additions are therefore considered to fall within the scope of the invention.