Standard vehicles such as vans and trucks have been used for the transportation of cargo. However, because of the height of the tray or bed above the ground, loading, unloading and positioning of cargo can be difficult.

In practice, devices such as fork lifts, lifting tailgates and ramps are used. These however have their disadvantages such as costs and availability at any particular site.

Attempts to overcome the above disadvantages have been made utilizing either pivoting trays or adjustable trays in which parallelogram linkages are employed.

With the pivoting type trays such as is shown in U.S. Patent 5,288,197, the back end of the tray is pivoted to the ground, forming a ramp up which the load is driven, in the case of vehicles, or pushed. This method of loading is not always convenient due to the problems of the loading onto an inclined ramp.

Adjustable trays have been proposed as shown in Australian Patent 57 3414 and Australian Patent Application 70142/91. In both of these specifications, parallelogram linkages in the form of "dog leg" or "boomerang" linkages are used, with the power means or rams acting on the linkages normal to the displacement of the tray. Further in both of these specifications the tray swings to a position rearway of the back of the vehicle, which could present

problems in use. In U.S. Patent 4,673,328 again a parallelogram type linkage is used having four pivotable tracks.

The construction shown in Australian Patent Application No. 70142/91 utilizes a complicated chassis construction with a torque box, rollover bar and support bars required to give stability to the yoke shaped chassis.

The present invention seeks to ameliorate the disadvantages of the prior art by providing a vehicle comprising

a tray having posts parallel to each other extending from the tray;

a yoke or U-shaped chassis having side wall extending substantially normal to the plane of the chassis;

parallel elongated members located in such side walls;

drive means to move said bed between a transport position and a loading position such that said tray retains substantially the same orientation tliroughout its movement between said transportation position and said loading position, with said elongated members being telescopically engaged with respective posts of the fray.

Preferably the elongated members and said posts are respectively normal to said yoke shaped chassis and said tray.

In another broad form the invention comprises a wheel assembly adapted for connection to a chassis comprising:

a first trailing arm pivotally suspended from a first end to the chassis;

a first wheel mounting stub axle located at or adjacent the fiee end of the first trailing arm;

a first connection means located adjacent said first wheel mounting stub axle;

a second trailing arm pivotally suspended, from a first end, to the chassis and angled with respect to the chassis in the direction as the first trailing arm;

a second wheel mounting stub axle located at or adjacent the free end of the second trailing arm;

a second connection means located adjacent said second wheel mounting stub axle;

a first bracket located on the chassis intermediate the said first and second training arms;

a second bracket located on the chassis on one side of the first bracket beyond said first wheel mounting stub axle;

a third bracket located on the other side of said first bracket beyond said second wheel mounting stub axle;

a pivoting linkage connected to said first bracket and extending on each side thereof;

a first leaf spring connected between one end of said pivoting linkage and said second bracket with said first connection means from said first connection means from said first trailing arm connected to the middle of said first leaf spring; and

a second leaf spring connected between the other end of said pivoting linkage and said third bracket, with said second comiection means connected to the middle of said second leaf spring.

In a further form the invention comprises a hydraulic control mechanism for a vehicle which has a yoke or U-shaped chassis, with a tray moveably supported thereon, which tray is moveable between a transport position and a loading position, with the fray remaining substantially horizontal during movement, comprising:

four hydraulic cylinders located adjacent the corners of the vehicle chassis to raise and lower die fray between the transport and the loading positions;

a hydraulic motor;

a hydraulic fluid sump;

a spool valve;

a first fluid line connected from said sump via said motor to said spool valve;

a second fluid line connected from said spool valve to said sump;

a third fluid line connected from said spool valve to a first flow divider/combiner which passes fluid through a first outlet to a second flow divider/combiner, and through a second outlet to a third flow divider/combiner, wherein each outlet of the second and third flow dividers/combiners is connected to one side of a respective one of said four hydraulic cylinders;

a fourth flow divider/combiner having a first and a second inlet, and an outlet;

a fifth flow divider/combiner having a first and second inlet and an outlet, with each inlet of said fourth and fifth flow dividers/combiners being connected to the other side of one of the respective cylinders;

a sixth flow divider/combiner having two inlets and an outlet, with its inlets each being connected to a respective outlet of said fourth and said fifth flow dividers/combiners, and its outlet being connected to said spool valve,

wherein said spool valve has a first position to allow fluid to flow in a first direction through the said flow dividers/combiners to move the pistons simultaneously to lower the fray, and second position to allow fluid to flow in a

second direction through the said flow dividers/combiners to move the pistons simultaneously to raise the fray.

The invention will now be described with reference to the accompanying drawings in which:

Figure 1 illustrates a rear view of a frailer with the bed in a loading position made in accordance with an embodiment of the present invention;

Figure 2 illustrates another rear view of the frailer shown in figure 1 with the bed in the transport position;

Figure 3 illustrates a view of the chassis shown in figures 1 and 2;

Figure 4 illustrates a view of the fray shown in figures 1 and 2;

Figure 5 illustrates a schematic rear view of a fray shown in figure 4 in its transport position;

Figure 6 illustrates a schematic rear view of the fray illustrated in figure

4 in its loading position;

Figure 7 illustrates a detailed view of the chassis of figures 1 and 2, showing the wheel suspension assembly;

Figure 8 illustrates a side view of the wheel suspension assembly of figure 7.

Figure 9 illustrates the front view of the fray illustrated in figure 4;

Figure 10 illustrates the hydraulic system according to one embodiment of the present invention;

Figure 11 illustrates the electrical system according to one embodiment of the present invention;

Figures 12 to 15 illustrate various configurations of trailers made in accordance with embodiments of the present invention; and

Figure 16 illustrates another embodiment of the trailing arm and suspension system.

A frailer is shown schematically in figures 1 and 2 embodying the present invention. The frailer (1) comprises a yoke-shaped chassis (2) and a drop fray (3). A tailgate (4) is located at the rear of the frailer (1); the tailgate (4) being hingedly connected to the side wall (6) or to the drop fray decking (5).

Thus in use the tailgate is unlatched and can be either swung to the side or dropped or lifted out, and then the drop fray (3) is lowered or dropped to the ground. However, as shown in figures 1 and 2 the tailgate (4) is hingedly connected to the fray floor (5).

The chassis (2) as shown figures 1, 2 & 3 comprises two top rails (7) joined by a top end rail (8). Reinforcing struts (9) link die top rails (7) and (8) to identical bottom side rails (10) and bottom end rails (11) respectively. Located at each corner of the chassis (2) are hollow tubes (12) which are adapted to telescopically mate with the upright post (13) of the fray (3).

Suitable cladding (not shown) is placed on the outer surface forming a stable side wall.

A drop fray (3) is constructed as shown in figures 4 & 9, having two side members (14) joined by fraverse members (not shown), with a decking (5) secured across on top. Upright posts (13) extend normal to the plane of the drop fray decking (5). A sheet (16) is connected normal to the decking (5) a distance away from the posts (13).

As shown in figure 9 gussets (17) are connected across the last two fraverse members (18) and the back plate (19).

The posts (15), in use, engage telescopically with the hollow tubes (12) as shown in figure 1, 5 & 6. The side sheet (16) as shown in figure 4 has nylon snips (20) located thereon to act as a bearing sfrip against die hollow tube (12).

As can be seen from this embodiment there is a hollow side tube (12) located on each comer of the yoke shaped chassis (2). In each of these tubes (12), a post (13) engages. This engagement enhances the rigidity of the vehicle.

To operate the tray (3), from its transport position to its ground engaging loading position, any suitable lifting means could be used such as motor driven thread and fixed nut arrangements, or cables. However, preferably as shown in figures 1 and 2, hydraulic cylinders (21) are connected to the side rail (7) and have their cylinder rod (22) passing through the bottom side rail (10) to engage with the side member (14) of the fray (2) at connection (23). A hydraulic cylinder (21) is located adjacent the four corners of the frame.

Thus to raise or lower the drop tray (2) the cylinders are activated simultaneously raising and lowering the fray (2) parallel to the plane of the chassis.

It is not necessary that the posts (13) and hollow tubes (12) be normal to the frame, as they could be at any suitable angle such as 45° to move the fray (2) rearward of the vehicle.

Further the male post could be on the chassis with the female hollow members on the fray.

An operating system will be described subsequently.

An improved suspension/wheel mounting system has been developed, an embodiment of which is shown in figures 1, 2, 3, 7 and 8.

This system utilizes two wheels (24) and (25) on each side of the chassis

(2). Each wheel (24) and (25) is connected to a stub axle (26) and (27) respectively, extending from a trailing arm (28) and (29) which are pivotally

connected to a support rail (15) attached to the bottom rail (10). Extending opposite the stub axles (26) and (27) at the free ends of the trailing arms (28) and (29) are projections (30) and (31). These projections are pivotally secured by any suitable means such as U-bolts (32) backing plate (33) and nuts (34) to the respective leaf springs (35).

Located intermediate the trailing arms (28) and (29) is a bracket (36) connected to the support rail (15). A first linkage (37) is pivotally connected intermediate its ends to the bracket (36). A first end (38) is pivotally connected to one end of the leaf spring (35), while the other end of the leaf spring (35) is connected by a pivotal linkage (39) to the support rail (15).

The second leaf spring (40) is pivotally connected at one end to the support rail (15) and connected at the other end by pivotal linkage (41) to the second end (42) of the first linkage (37).

To transfer weight back to the chassis (2) a support plate (43) is provided as particularly shown in figures 7 and 8. The trailing arms (28) and (29) are mounted on a respective projection (44) with a bush and spacer (not shown). The support plate (43) has located at one end tubular section (47) which fits over the free end of the projection (44), with the cut out (48) accommodating the trailing arm (28), as shown in figure 7. The edge (49) of the support plate (43) is welded to die reinforcing struts (9), thus securing the trailing aim (28) and transferring the load back to the chassis (2).

A modified suspension system is shown in figure 16 wherein a detailed view of me suspension connection to the trailing arm is shown.

The arrangement of the wheel suspension is as described previously, except that the leaf spring (35) are at their centres supported by a spring holder (95), which is supported on a bearing (97) to the member (96) which is secured to the trailing arm (28).

The tailgate (4) is raised and lowered by the tailgate cylinder (50) which is connected to the fray (3) by connection (51) and to the linkage (52) on the tail gate (4) as shown in figure 1.

Figure 10 is a schematic of the hydraulic system of one embodiment of the present invention. A hydraulic motor (53) draws fluid from the sump (54) and pumps it to a solenoid spool valve (55). In a first position the spool valve (55) passes fluid through to a first flow divider/combiner (56) such as those sold under the frade mark Hydraform, which has two outlets dividing the flow to two further flow dividers/combiners (57) and (58). The flow dividers/combiners being set to equally distribute the flow. The output of each of the flow dividers/combiners (57) and (58) communicates with the power side or extension side of a respective fray operating cylinder (59, 60, 61 and 62), with the return side or refraction side of d e cylinders being connected to respective inputs of flow divider/combiners (63) to (64), the outputs of which are combined through the flow divider/combiner (65) and back into the sump (54). The spool valve (55) has a second position wherein the flow is reversed through the flow dividers and the pistons are refracted.

Pilot check valves (66, 67, 68 and 69) can be connected directly to the cylinders (59, 60, 61 and 62) as shown or a single pilot check valve (not

shown) can be connected between the flow dividers (56 and 57) and the spool valve (55).

To operate the tailgate cylinder (50) an additional spool valve (70) is connected via die spool valve (55) to the hydraulic motor drive fluid, to open or close the tailgate depending on the position of the spool valve (70).

Shown in figure 1 1 is the electrical schematic circuitry. As can be seen the frailer is self powered having its own battery. The circuitry provides a provision for direct charging of the frailer battery from the car to which it is connected.

The floor down solenoid (84), floor up solenoid (85), tailgate down solenoid (86), and tailgate down solenoid (83) are connected via the respective floor down relay (87), floor up relay (88), tailgate down relay (89) and tailgate up relay (90) to the hydraulic valves (91) located next to the hydraulic mortar (92).

The wheels each have an electric brake (93) operated by the electric brake relay (94).

Separate locking mechanisms are provided to lock the fray in its transport position. This can utilize any suitable arrangement coupled with a fail safe system to prevent operation of the tray if the fray is still locked to die chassis.

Further, in the line to the tailgate cylinder, is a pressure sensitive valve whereby if an object is blocking the closing of the tailgate the increase in resistance to the movement of the ram is detected and the ram is disabled until the object is removed.

The basis chassis construction can be used with many different body panel designs. One embodiment is shown in figure 12 in which storage units (71) are rigidly connected to the chassis (2) and the support plates (43), to provide additional rigidity of the chassis (2).

The trailer (1) as shown in figure 12 can be modified to include a canopy (72) covering a framework (73) as shown in figure 14, or a caπying rack (74) as shown in figure 13.

The basic frailer chassis can be modified to produce a horse float (75) as shown in figure 15. The operation of the fray is identical to the previously described operation, and the trailer chassis and wheel suspension systems are substantially identical to these described previously.

The addition of the roof bracing (76) and the storage units (77) which are also connected to the support plates (43) resist any twisting of me horse float (75). The horse float body has a back enfrance door (78) and a front door (79).

The tray is divided into two stalls with appropriate horse padding on the divider and side walls (81). Each stall has its own rear door (80).

It should be obvious tiiat modifications and alterations could be made to the above described invention without departing from the scope or spirit of the present invention.