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. 17, 1977
Filed:
Nov. 03, 1975
Melvin Claude Jackovich, Stillman Valley, IL (US);
Sundstrand Corporation, Rockford, IL (US);
Abstract
In a vehicle wherein power is applied to each track or wheel through a hydrostatic transmission and control system including: a displacement control unit for regulating each transmission; a steering control valve associated with each displacement control unit for modifying the operation of the displacement control unit; and a speed and direction control unit for applying hydraulic pressure to each of the displacement control units for controlling the basic direction and speed of the vehicle; wherein the maintenance of the desired direction of operation of the vehicle is enhanced by an electronic tracking control circuit that includes: means for measuring the actual speed of each track; a phase comparator for providing a signal indicating the difference in track speeds; an integrator for providing a signal proportional to the difference in speed as measured over time; and comparator circuits responsive to the integrator for triggering a solenoid control valve connected between the appropriate steering control valve and displacement control unit to open, thereby reducing the speed of the faster moving track in order to maintain the desired direction of operation. Either a straight line or curved path of operation for the vehicle can be selected by adjusting bias voltages applied to the integrator. Additional circuitry is provided to deactivate the electronic tracking control when either of the steering control valves is actuated.