Roof support for underground excavations such as coal mines
US5178494A · kind A · utility
6Cited by
2References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 26, 1991 |
| Grant date | Jan 12, 1993 |
| Priority date | — |
| Expiry date | Sep 26, 2011 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21D23/0017
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A roof support for the ceilings of excavated spaces underground and particularly for supporting caving edges for pillar recovery in coal mines is described. The roof support has a roof bar connected to a base frame by hydraulically extendable props and by a lemniscate mechanism. The props are articulated to the base frame and to the roof bar. A link of the lemniscate mechanism has a predetermined bending point. Since this link fails when overloaded before the remainder of the apparatus, it is the only element that need be replaced when the apparatus is overloaded. Thus, the device may be economically repaired.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.