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:
Apr. 16, 1991
Filed:
Jul. 28, 1989
Allen P Forsyth, Portland, OR (US);
Atlas Copco Construction and Mining Holding AB, Stockholm, SE;
Abstract
A hydraulically-actuated controller is disclosed for controlling delivery of hydraulic fluid from a variable-displacement, pressure-compensated pump to a hydraulically-powered reel on which is wound a cable or other flexible member extending from the reel to a tie point. Rotation of the reel is controlled appropriately to maintain the cable tautly between the reel and tie point as the distance therebetween changes. One use is on an electrically-powered mining vehicle, the power cable of which extends from a fixed power source to the vehicle-mounted reel. The controller is in a pay-in-mode whenever the distance between the reel and tie point is decreasing or remaining constant, and in a pay-out mode whenever said distance is increasing. During pay-in, pressurized hydraulic fluid is directed from the pump to the reel motor. During pay-out, pump output is occluded and fluid is directed through a restriction from the reel motor to the reservoir, the restriction serving to brake motor rotation. Two of four valves in the controller are hydraulically piloted in each position and biased in the pay-in position. A separate check valve ensures that pressure at the pilots is about equal during pay-in but unequal, favoring the pay-out position, when the reel is paying out cable.