Draw works transmission control
US4278155A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 2, 1979 |
| Grant date | Jul 14, 1981 |
| Priority date | — |
| Expiry date | May 2, 1999 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/87185
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
PCT No. PCT/US79/00293 Sec. 371 Date May 2, 1979 Sec. 102(e) Date May 2, 1979 PCT Filed May 2, 1979 PCT Pub. No. WO80/02446 PCT Pub. Date Nov. 13, 1980. In a control (28) for a hydraulically operated draw works or the like having a hydraulically disengaged brake (14), a transmission (10, 12) and a brake control valve (114, 122), the improvement including an accumulator (174) having a check valve (196) connected between the brake control valve outlet (152) and the brake (14) to modulate the application of the brake (14) after the brake (14) has been fully released and to provide no modulation of brake (14) application after the brake (14) has been only partially released to thereby minimize shock in the draw works components when a load is lowered rapidly and yet provide rapid action when operated slowly.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.