Land vehicles – Wheeled – Articulated vehicle
Reexamination Certificate
2000-08-29
2001-07-17
Johnson, Brian L. (Department: 3618)
Land vehicles
Wheeled
Articulated vehicle
C280S432000, C280S485000, C267S138000
Reexamination Certificate
active
06260873
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a hitch for connecting a drive vehicle to an object which is to be moved. The hitch has means for damping forces between the object and the drive vehicle.
BACKGROUND OF THE INVENTION
Although the hitch of the invention may be used in a number of various applications, for ease of illustration, the invention will be discussed primarily as it relates to the phenomenon known as power hop. Power hop is a condition of vehicle in which a vehicle (tractor) bounces, primarily in the vertical mode, and causes ride discomfort for the vehicle operator. Power hop occurs when a vehicle (tractor) is pulling an attachment (implement) which applies a significant resistance force to the vehicle. This resistance force of the attachment in the fore-aft (tangential) direction can reach up to 50% to 100% of the vertical load of the vehicle, and is constantly varying. This resistance force of the attachment is referred to as the drawbar load. The variation of these resistance forces contributes to power hop. Power hop can occur on any surface, with any vehicle pulling any sort of object. An agricultural tractor pulling an implement (disk, chisel plow, field cultivator, subsoiler ripper) under soil tillage conditions is one such example.
It is an object of the invention to provide a device designed to minimize or eliminate the occurrence of power hop by dampening the variation of the resistance forces between the vehicle and its implement, and by isolating or modulating the frequency variations of the drawbar load.
It often occurs, when a vehicle pulls an object, such as when a truck tractor pulls a trailer, or a farm tractor pulls a plow, or a truck or tractor pulls a tree stump, that forces directly applied by the drive vehicle (tractor), by the drive tires through the hitch connecting the drive vehicle with the object, must overcome an initial large resistance to movement (inertia, friction, surface tension) by the object, i.e., the trailer, plow or tree stump, before the object begins to move. Before the object begins to move, the forces exerted by the drive vehicle are stored as energy somewhere in the drive vehicle or between the drive vehicle and the object. Often, when the resistance is overcome, and the object begins to move, all the stored energy is released in the instant of first movement, and the object lurches or hops ahead, or if the object doesn't move, the drive vehicle begins to hop.
It is another object of the present invention to provide a connection means between a drive vehicle and an object that smoothes out the variation of resistive forces in order to reduce or eliminate lurch or hop of an object to be moved, or the hop of a drive vehicle.
Other objects of the invention will be apparent from the following description and claims.
SUMMARY OF THE INVENTION
The invention relates to a hitch for connecting a drive vehicle to an object to be moved. The hitch of the invention comprises (a) a rigid container for containing a damping means, (b) a first connecting means associated with a first end of the rigid container wherein an exterior portion of the first connecting means is outside the rigid container, and the first connecting means is movable relative to the rigid container, (c) a second connecting means associated with a second end of the rigid container wherein an exterior portion of the second connecting means is outside the rigid container, and the second connecting means is movable relative to the rigid container, (d) and the damping means interacts with the first and second connecting means.
In one illustrated embodiment of the invention, the hitch comprises a box of rigid material having a cross section having at least two parallel sides wherein a first connecting means is associated with a first end of the box, and an exterior portion of the first connecting means is outside the box and an interior portion is within the box, and the first connecting means is movable relative to the box between the at least two parallel sides, and a second connecting means is similarly disposed. Elastomeric material may be used as the damping means.
In another embodiment, the container of the hitch may comprise a cylinder made of a rigid material, wherein said first and second connecting means are associated with opposed ends of the cylinder. A hydraulic fluid may be contained within the cylinder to restrict the movement of the first and second connecting means.
In another embodiment, the hitch may comprise a rigid container made of a rigid material wherein a first spring is contained within the rigid container between the first and second connecting means, a second spring is contained within the rigid container between a first end of the rigid container and the first connecting means, and a third spring is within the rigid container between a second end of the rigid container and the second connecting means.
In a further embodiment, the hitch may include a hydraulic fluid contained within said container in combination with springs.
Also provided is a drive vehicle/object combination connected together using the hitch of the invention.
Also provided is a method for connecting a driving vehicle to an object using the hitch of the invention.
REFERENCES:
patent: 1734072 (1929-11-01), Blalack
patent: 1991684 (1935-02-01), Ketel
patent: 2783039 (1957-02-01), Wilson
patent: 3881577 (1975-05-01), Wherry et al.
patent: 4029307 (1977-06-01), Nielson
patent: 4114921 (1978-09-01), Thorell et al.
patent: 4817978 (1989-04-01), James
patent: 4968010 (1990-11-01), Odobasic
patent: 4978133 (1990-12-01), Thorne et al.
patent: 5195768 (1993-03-01), Hendrix
Bishel Steven George
Liu Shaobo
Johnson Brian L.
Lerner Avraham H.
The Goodyear Tire & Rubber Company
Wheeler David E.
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