This invention is in the field of vehicles and in particular the wheels supporting such vehicles.

BACKGROUND

Typical trucks, trailers, and like vehicles have a body fixed to a frame that is supported on one or more axles with attached wheels. Conventionally, the axles are mounted to the frame through a suspension unit of some kind, typically incorporating springs, airbags, and the like, whereby the axle can move up and down with respect to the vehicle frame to absorb shock. Commonly the axle will extend from one side of the vehicle to the other, and have one or more wheels at each end. In any event, as the vehicle moves along a road, each axle moves up and down independently as the road surface varies, and each axle imparts a different and constantly varying force through its suspension unit to the frame and the vehicle body, causing considerable stress to the frame and body.

Similarly the road surface is also subjected to these constantly varying forces and damage is incurred as the wheels move up and down against the road surface. As well, conventional vehicles typically have a pair of wheels on each end of each axle, with none in between, such that the weight of the vehicle is born by a relatively narrow strip of the road surface on each side of the vehicle. This concentration of weight leads to road damage as well. Heavy haul vehicles are known for hauling unusually heavy loads, such as buildings, and large equipment, where wheels are placed under middle portions of the vehicle as well so that the load is carried by a larger area of the road surface. In such uses the weight per square inch of tire that contacts the road surface is typically about the same as in a conventional vehicle with a normal load. In such vehicles the axle is mounted conventionally to the frame through a suspension unit and the greater loads are accommodated by providing many more wheels than are typically used for vehicles.

Vehicles are also known where the axle is simply fixed to the frame such that the axle and frame move together, and the only dampening of the constantly varying forces is provided by the flexibility of the rubber tires between the wheel and the road.

SUMMARY OF THE INVENTION;

It is an object of the present invention to provide a vehicle apparatus that overcomes problems in the prior art.

The present invention provides a vehicle apparatus that reduces variations in forces on the vehicle body as the vehicle apparatus moves along a road. The vehicle apparatus comprises a frame with the axles attached to the frame such that the vertical distance between the axles and frame is constant, and wherein the vehicle body is attached to the frame through a plurality of suspension units comprising springs, air bags, and the like. The axles, and attached wheels, and frame thus move up and down together, and the movement of the frame is essentially an average of the movement up and down of all the axles supporting the frame. Thus each axle does not exert an independent force on the vehicle body, and variations in forces experienced by the vehicle body are reduced.

In the prior art, the wheels at each end of each axle move independently in response to the forces imparted upon them as the vehicle moves over the road. The vehicle apparatus of the invention limits the up and down movement of each wheel by fixing each wheel to the frame with the result that the wheels roll forward in accordance with the orientation of the frame and not independently in accordance with the road, thus reducing the variations in force of the wheels on the road surface.

The wheels can be distributed across the width of the vehicle apparatus, and can be mounted on axle arms that pivot about a vertical axis, such that outside wheels can be pivoted out of the way to allow access to inside wheels for maintenance. The pivoting mount can also allow the wheels to pivot somewhat during turns, reducing scrubbing of the wheels against the road.

DESCRIPTION OF THE DRAWINGS:

While the invention is claimed in the concluding portions thereof, preferred embodiments are provided in the accompanying detailed description, which may best be understood in conjunction with the accompanying diagram where like parts are labeled with like numbers, and where: Fig. 1 is a side view of the axle frame attached to the rear end of the vehicle body;

Fig. 2 is a side view of a wheelset with one wheel of the tandem set removed, schematically illustrating the attachment of the axle arm to the axle frame;

Fig. 3 is a top view schematically illustrating an arrangement of wheelsets under the axle frame;

Fig. 4 is a side view illustrating the frame coupler;

Fig. 5 is schematic cross-section view along line 5-5 in Fig. 1;

Fig. 6 is a schematic top view of an embodiment of the alignment rod and its attachment between the frame and axle arm.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS:

Fig. 1 illustrates a vehicle apparatus 1 of the present invention comprising a vehicle body 3 rigidly attached to a body extension member 5.

An axle frame 7 is supported on a plurality of axles 9 and attached wheels 10. The axles 9 are mounted to an axle arm 11 that is pivotally mounted to the axle frame 7 about a vertical pivot axis PA. Thus the axles 9 and wheels 10 can pivot about the vertical pivot axis PA, as illustrated in Fig. 2, but do not move up and down with respect to the axle frame 7. The illustrated embodiment shows the axle frame 7 mounted at a rear end of the apparatus 1, such that the apparatus is designed for travel in an operating travel direction T. In alternate embodiments, there could be such an axle frame 7 at each end of the vehicle apparatus 1.

The body extension member 5 extends out from the vehicle body 3 over the axle frame 7, and is attached to the axle frame 7 through suspension units illustrated as airbags 13. The suspension units could alternatively comprise springs, as are known in the art, or a like cushioning mechanism that will allow the body extension member 5 to move up and down with respect to the axle frame 7. Thus instead of each axle 9 exerting a constantly varying upward force on the vehicle body 3 through an individual suspension unit, the up and down movement of the axle frame 7 is an average of the movement up and down of the wheels 10 and axles 9, and it is this averaged movement that is transmitted through the suspension units to the body extension member 5 and thus to the vehicle body 3.

In addition to the air bags 13, the front end 15 of the axle frame 7 is coupled to the rear end 17 of the vehicle body by a frame coupler 19, as illustrated in Fig. 4. The frame coupler 19 is pivotally attached at the front end to the vehicle body 3 and at the rear end to the axle frame 7, by pins 21 through brackets 23. Thus the vehicle body 3 can move vertically with respect to the axle frame 7 as the airbags 13, or like suspension units, flex during operation. The frame coupler 19 illustrated in Fig. 4 may be curved and may be made from spring steel, such that the vehicle body 3 and axle frame 7 can move somewhat with respect to each other. Where the suspension units include leaf springs, the leaf springs could serve to couple the axle frame 7 to the vehicle body 3.

The illustrated embodiment comprises nine tandem wheel sets 30 arranged as illustrated in Fig. 3. This arrangement distributes the weight of the vehicle apparatus 1 across a substantial width of the roadway, reducing damage to the road surface. As seen in Fig. 5, each wheel set 30 comprises a pair of wheels 10 mounted on a short axle 9. The axle 9 is attached to an axle arm 1 1 which angle upward and forward to a vertical arm portion 31 that is inserted in a bushing 33 in the axle frame 7. The axle arm 11 can thus pivot about the vertical pivot axis PA, but is fixed vertically with respect to the axle frame 7.

As seen in Fig. 2, the wheel sets 30 are maintained in alignment by an alignment rod 35 fixed between the axle frame 7 and the vertical arm portion 31. This rod 35 can be made somewhat flexible to allow the axle arm 1 1 to pivot somewhat during turns to reduce scrubbing of the wheels 10 against the road surface, but at the same time maintain alignment for road travel. Fig. 6 illustrates one embodiment of the alignment rod 35 comprising springs 37 bearing against either side of a frame bracket 36 attached to the axle frame 7. Adjusting nuts 39 allow for proper adjustment of the rod for proper alignment of the wheelset 30 in the operating travel direction T.

A problem with distributing wheels 10 across the width of the axle frame 7 as in the illustrated embodiment is that it is very difficult and time consuming to change a tire or do other maintenance on the inside wheel sets 30A. In the illustrated embodiment, this difficulty is much reduced. The inside wheel sets 3OA are accessed by jacking up the axle frame 7, disconnecting the alignment rod 35, and then pivoting the outside wheel sets 30B out and away.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.