Elastomerically isolated tow hitch drawbar
AssigneeRobin Industries, Inc.
InventorLeonard A. Lorman
Life of this patent
Estimating the term…
Abstract
A damped drawbar for use in towing a drawn trailer that provides for the attenuation of noise, shock, and vibration that may be conducted into the towing vehicle. The newly designed drawbar uses a resilient elastomer, operating in shear, sandwiched between an outer steel tube and an inner steel tube, to reduce noise by damping the undesirable vibrations. A cushioned hitch pin coacting with the ovate holes in the inner tube, reduces the noise from a jolt caused by the hitch pin over-travel, during acceleration or deceleration, by as much as 95 percent. The hitch pin coacting with the ovate holes in the inner tube, serves as a mechanical fail-safe should the towed member be grossly beyond the drawbar's rated load capacity.
Claims17
A drawbar for a tow hitch, comprising:
- an inner housing and an outer housing with a longitudinally mounted elastomeric member therebetween, the elastomeric member comprising a resilient linear damping element communicating with both the inner and the outer housing with a resistance to omnidirectional forces applied to the drawbar from a towing vehicle or a drawn load;
- the inner and outer housing each having a pair of coincident cross holes;
- wherein each of the cross holes of the inner housing are larger than the corresponding cross holes of the outer housing.
An elastomerically isolated tow hitch drawbar comprising:
- a square inner tube welded to a bracket of a towed load, the inner tube displaced within a square outer tube with at least one elastomeric sleeve compressed between the inner and the outer tube to provide total isolation from noise or vibration that may be conducted from one tube to the other;
- the inner tube having ovately shaped cross holes on both sides, wherein a horizontal diameter of each of the holes is larger than a vertical diameter thereof, and wherein, the inner tube cross holes are coincident with circular cross holes of the outer tube;
- wherein the outer tube is slidably insertable into standard a receiver tube of a towing vehicle, the receiver tube including cross holes on both sides, with a hitch pin insertable through the tube holes to secure the towed load to a low vehicle provides a clamp to absorb any play between the receiver tube and the drawbar tubes and to direct all of the shock, noise, bounce and vibration that are typically related when towing through the at least one elastomeric sleeve.
An elastomerically isolated tow hitch drawbar comprising:
- an outer tube welded to a bracket of a towed load having an inner tube displaced within the outer tube with at least one elastomeric sleeve compressed between the inner, and the outer tubes to provide total isolation from noise or vibration that may be conducted from one tube to the other;
- wherein a forward end of the inner tube extends beyond and projects from a forward end of the outer tube, the inner tube having ovately shaped cross holes on both sides, which are coincident with circular cross holes of the outer tube to receive a clamp inserted in the tube holes to retain the inner tube within the outer tube;
- the inner tube including cross holes on each side near its forward end;
- and, the inner tube slidably insertable into a receiver tube of a towing vehicle, the receiver tube including cross holes on both sides to receive a hitch pin insertable through the inner tube and receiver tube holes to secure the towed load to the tow vehicle, wherein the clamp absorbs any play between the receiver tube and the drawbar tubes and directs all of the shock, noise, bounce and vibration that are typically related when towing through the at least one elastomeric sleeve.
Dependencies are inferred from the claim text.