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.