Mine roof supports
US5039257A · kind A · utility
11Cited by
2References
13Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | May 11, 1990 |
| Grant date | Aug 13, 1991 |
| Priority date | — |
| Expiry date | May 11, 2010 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21D23/0436
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Mine roof support comprising a base including a pair of skids, a roof engaging canopy, jacks acting between the base and the canopy, an auxiliary jack connected to the base for lifting or lowering at least part of the base when the support advances and a lost motion arrangement connected between the base and the auxiliary jack for aiding movement of the base and the roof engaging canopy toward each other. The lost motion arrangement is connected to each of the skids by a pivotal connection which permits the front end of one skid to move vertically to a limited extent with respect to the front end of the adjacent skid.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.