Apparatus and method for controlling driving of a ram of a hydraulic cylinder of a hydraulic press equipment
US5682742A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 23, 1996 |
| Grant date | Nov 4, 1997 |
| Priority date | — |
| Expiry date | May 23, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB30B15/161
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Apparatus and method for controlling equipment of driving a ram of a hydraulic press. Four proportional sheet valves PA, PB, TA and TB are connected with a hydraulic circuit, in which a hydraulic cylinder 2 for driving a ram 1, a hydraulic pump 3 and so on are set up, a so as to form a full-bridge hydraulic circuit. A compression proportional sheet valve PAp and a hydraulic pump 40 are connected as a hydraulic power source with high pressure and small flow rate parallel with the sheet valve PA being in the oil supply position side in the hydraulic circuit. An NC controller controls timing of turn-on of the proportional sheet valves PA, PB, TA and TB as well as change of the valves PA and Pap by PWM signal to pilot valves of the sheet valves PA, PB, TA and TB. The valves PA and TB are turned on in the down stroke of the ram 1, the valves PB and TA are turned on in the up stroke of the ram 1, and the valve Pap is turned on in the compression stroke.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.