Rock drilling apparatus
US4503918A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 16, 1983 |
| Grant date | Mar 12, 1985 |
| Priority date | — |
| Expiry date | Jun 16, 2003 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B44/02
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A rock drilling apparatus for drilling with high pressure hydraulic jet including a rock drill body (11), a drill tool (12) coupled to said body (11) and a feeding device (15) with a motor (16) for feeding said body and tool to and fro the working face. The drilling tool (12) has an inner rotating tube (40) with a high pressure nozzle body (41) at the nose thereof and an outer tube (42) surrounding said inner tube (40). Said outer tube (42) is provided with a hard metal collar (61) at the front end for protecting the nozzle body (41) and for calibration of the drill hole size. A sensing device including a pressure operated switch 73 and an adjustable time relay (83) is adapted for sensing the feed resistance met by said collar (61) and causing said feed motor (16) to retract said drill body (11) and tool (12) when a preset value of the resistance is exceeded.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.