Pump controlling apparatus for construction machine
US5048293A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 21, 1989 |
| Grant date | Sep 17, 1991 |
| Priority date | — |
| Expiry date | Dec 21, 2009 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE02F9/2296
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A hydraulic drive controlling apparatus for a construction machine has at least one variable displacement type hydraulic pump, a plurality of actuators driven with a hydraulic fluid from the hydraulic pump, directional control valves driven in accordance with amounts of manipulation of operation means for controlling the plurality of actuators, means for detecting a delivery pressure of the hydraulic pump, means for selecting maximum one of load pressures of the plurality of actuators, and first control means for controlling displacement of the hydraulic pump to bring a differential pressure between the delivery pressure and the maximum load pressure to a specified value. The hydraulic drive controlling apparatus further has second control means for controlling the displacement of the hydraulic pump to bring the delivery pressure thereof to a predetermined value, first command means for selecting a mode of control of the displacement of the hydraulic pump and outputting a corresponding command signal, and first selection means for selecting one of the first and the second control means depending upon the command signal from the first command means.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.