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:
Feb. 28, 1978
Filed:
Jan. 14, 1977
Karlmann Hamma, Tettnang, DT;
Willy Holdenried, Immenstaad, DT;
Zahnradfabrik Friedrichshafen AG, Friedrichshafen, DT;
Abstract
A system for controlling the operation of a reversible hydrostatic transmission including an engine-driven pump, particularly for a self-propelled utility vehicle such as a forklift truck, comprises a switchover member coupled with a setting lever of the hydrostatic pump which is biased by a pair of counteracting springs into a normal centered position. A shift lever, upon being moved from 'neutral' to 'forward' or 'reverse', causes a displacement of the switchover member into a corresponding off-normal position by a fluidic or electromagnetic directive force generally proportional to engine speed. At a speed exceeding a certain limit in either direction, the switchover member deactivates the fluidic or electric operating circuit for the opposite direction whereby a shift from 'forward' to 'reverse', or vice versa, will let a change in direction take place only after the switchover member has been restored to near-normal exclusively by its biasing springs against the gradually decaying directive force previously applied. A pedal-operated linkage, coupled with the switchover member, serves for a rapid restoration of that member to normal or for fine speed control at near-zero velocities.