Mill hydraulic screw-down
US3974672A · kind A · utility
Inventor
Key dates
| Filing date | Sep 19, 1975 |
| Grant date | Aug 17, 1976 |
| Priority date | — |
| Expiry date | Sep 19, 1995 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB21B37/62
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A hydraulically driven mill screw-down including an optical encoder directly coupled to the hydraulic drive for producing digital signals representative of motion and direction of motion of the movable roll, a bidirectional counter for maintaining a cumulative count representative of roll position, a pulse source, a bidirectional reference counter for maintaining a count representative of desired roll position, a digital subtractor for producing a difference signal, an analog-to-digital converter for producing an analog signal proportional to the digital difference signal, a servo amplifier and a continuously variable hydraulic valve for controlling the application of fluid pressure to the hydraulic screw-down apparatus. Also disclosed is an emergency stop preset register for dumping an emergency stop desired position into the reference counter when actuated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.