Replacing mains
US4674914A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 14, 1985 |
| Grant date | Jun 23, 1987 |
| Priority date | — |
| Expiry date | Jan 14, 2005 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B7/30
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
The invention relates to a self-propelled apparatus 1 for replacing main such as a gas main 2, comprising a single double acting hydraulic piston and cylinder combination 3 connected with slidable devices 4, 6 operable by the device for step-by-step movement of the apparatus through the main on alternate strokes of the combination, the devices 4 and 6 being operative in only a forward direction to slide to grip the main, the apparatus drawing a vibratable breaker device 20 (FIG. 2) or 30 (FIG. 3) through the main, the device being vibratable to precess about an axis and the device 30 being vibratable by percussive means longitudinally of the main.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.