Anti-two block system
US4523686A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1984 |
| Grant date | Jun 18, 1985 |
| Priority date | — |
| Expiry date | Aug 31, 2004 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB66D1/44
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
An improved anti-two block system having a boom hoist drum driven by a first hydraulic motor with a first variable displacement motor controlled by a first ram moveable in a given direction to supply fluid pressure for driving the boom drum to lower a boom and a hook block drum driven by a second hydraulic motor with a second variable displacement pump controlled by second ram moveable in a given direction to supply fluid pressure for driving the hook drum to raise a hook block. A differential mechanism sums the movement of the hook block and boom and activates a switch to energize solenoid valve means, when the hook block is a predetermined distance from the boom, to preclude movement of said rams in the given directions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.