Clutching and braking control for hydraulically driven crane winches
US4447044A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 26, 1981 |
| Grant date | May 8, 1984 |
| Priority date | — |
| Expiry date | May 26, 2001 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16D67/04
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A control system for one or more hydraulically driven crane winch drums each having a hydraulically actuated clutch and a brake. Included is a negative braking mechanism having a brake cylinder of the single-acting, spring-return type for normally holding the brake applied by the force of the spring and releasing the brake on fluid pressure actuation. A mode selector valve selectively delivers hydraulic fluid under pressure from two separate sources to the clutch and the brake cylinder in order to condition the winch for a selected one of winching, brake-locking, and free-fall modes. The mode selector valve causes the negative braking mechanism to release the brake in the free-fall mode, so that a positive braking mechanism is also provided to permit the operator to arrest the free fall of the load, or the free running-out of the cable, in an exact position desired.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.