Hydraulic drive system for construction machine
US5488787A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 3, 1994 |
| Grant date | Feb 6, 1996 |
| Priority date | — |
| Expiry date | Aug 3, 2014 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE02F9/2246
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
When a prime mover (1) is driven, a controller (25) outputs an open-drive signal for bringing an opening/shutting valve (23) into an open position and, upon a control lever (68, etc.) being operated, a hydraulic fluid is supplied from an auxiliary hydraulic pump (7) through pressure reducing valves to driving sectors of directional control valves (8 to 16) for shifting them. A flow rate and a direction of flow of the hydraulic fluid from main hydraulic pumps (3, 4) are thereby adjusted so that actuators (57A, 57B, 57C, 56A, 54) can be each operated at a speed depending on the amount by which the control lever is operated. When one of the actuators (57A, 57B, 57C, 56A, 54) is to be driven when the prime mover (1) is not driven, an open command is selected in a selection command device (24), whereupon the controller (25) outputs the open-drive signal, causing the opening/shutting valve (23) to open a line interconnecting the accumulator (21) and the pressure reducing valve (17), etc. By now operating the control lever (68), for example, the directional control valve (9) is shifted so that a boom cylinder (57A) is operated with the dead weight of a working unit to allow a descent ther…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.