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. 12, 1980
Filed:
Aug. 28, 1978
Kenneth V Johnson, Oconomowoc, WI (US);
Bucyrus-Erie Company, South Milwaukee, WI (US);
Abstract
A hydrostatic winch having a hydraulic drive system with a dual control valve which adjusts pressure in control lines for varying the speed of lowering and hoisting a load and a brake for stopping the load has an overspeed control system which includes first valve means for relieving pressure in the control lines and first valve control means which opens the valve to automatically slow the speed of the winch when the load is moving too fast and a fail safe system for smoothly stopping the load, if necessary, which includes a braking system having a normally 'off' brake which is biased towards an 'on' position but which is held in the 'off' position by a hydraulic cylinder. The braking system also includes a first means for determining when the speed of the load or winch exceeds a predetermined safe rate, second means for detecting the occurrence of an abnormal condition which can cause overspeed, second valve means for bleeding pressure from the hydraulic cylinder and second valve control means which upon receipt of a signal from either the first or second means will open the valve to proportionately bleed hydraulic pressure from the hydraulic cylinder of the brake so as to apply the brake to smoothly stop the load. In a preferred embodiment the fail safe system includes an operator control override system.