The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 23, 1978
Filed:
Apr. 12, 1977
Basil White, Rockford, IL (US);
Twin Disc, Incorporated, Racine, WI (US);
Abstract
A power transmission control system for vehicles where it is desired to reverse the vehicle direction at full throttle such as vehicles used in mining operations, off road application, or the like. The transmission includes selectively and hydraulically operated friction-type clutches and hydraulic control circuits for actuation thereof. The hydraulically operated output clutches are used to change speed range of the transmission while input clutches are used to change speed and/or direction of the vehicle. The control mechanism permits the vehicle in motion to be shifted to a reverse direction at full throttle and the arrangement is such that when the shift is made, the output speed range clutch disengages or optionally drops to residual torque capacity, the forward clutch remains fully engaged, and the reverse clutch comes on fully to brake the input. Then both forward and reverse clutches are engaged. The input is then locked. The output speed range clutch is then brought to increased 'brake mode' torque capacity. The output speed range clutch then functions as a brake to decelerate the vehicle. The static braking reaction torque is held by the locked up direction clutches. When the vehicle speed reaches a predetermined lower value (where it is almost stopped) that situation is sensed by the hydraulic control means and immediately thereafter and simultaneously the forward clutch is released and apply pressure on the braking (output speed range) clutch is permitted to increase to full value. The vehicle then accelerates in the opposite direction under the influence of the torque converter. This control system also provides means for quick and smooth full throttle shifts at and near vehicle stopped condition; that is for either a neutral into range shift or a directional shift.