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:
Nov. 07, 1989
Filed:
Dec. 10, 1982
Lambert Haner, Rocky River, OH (US);
Commercial Shearing, Inc., Youngstown, OH (US);
Abstract
A constant speed hydrostatic drive system is disclosed wherein a generator drive shaft is maintained at a constant speed by utilizing an electro-hydraulic controlled displacement pump responsive to a pressure transducer to control a hydraulic motor. A speed sensor is used to produce a direct current signal responsive to the drive shaft speed. The signal is converted into a series of voltage pulses also responsive to the shaft speed which are compared to a speed reference signal to provide a speed error signal. A loop gain control means is provided to utilize said speed error signal to adjust the shaft speed to coincide with said reference signal. A timing reference and digital trim control are also provided to compensate for long term drifting in the type speed control circuit described above.