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:
Aug. 14, 1984
Filed:
Dec. 21, 1981
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
A hydraulic power system having a variable displacement hydraulic pump, a hydraulic motor driven by the hydraulic pump for actuating a load, the pump and motor being connected to constitute a closed hydraulic circuit, hydraulic servo for controlling the displacement volume of the pump, and motor stopping device including a brake arrangement adapted to release the motor from a braked condition when a control pressure from a hydraulic fluid source is received. The system includes a control valve responsive to a main line pressure in the closed hydraulic circuit for controlling a hydraulic fluid supply to the servo to prevent the main line pressure from substantially exceeding a predetermined level, first pressure transmission control interlocked with an input of the servo for transmitting the control pressure to the brake arrangement when the input is actuated, and a second pressure transmission control responsive to the pressure of a hydraulic fluid supply to the servo on the output side of the control valve for transmitting the control pressure to the brake arrangement when the supply pressure is substantially lower than a normal supply pressure of the hydraulic fluid source.