Pneumatic ram boring device
US4250972A · kind A · utility
Inventor
Key dates
| Filing date | Mar 30, 1979 |
| Grant date | Feb 17, 1981 |
| Priority date | — |
| Expiry date | Mar 30, 1999 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B4/145
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A self-propelled pneumatic ram boring device for boring holes in the ground comprises a percussion piston which is reciprocable in a housing, and a control sleeve which controls the forward and rearward movement of the piston by passing over radial control ports in the piston. In order to control the device to move either forwards or rearwards, without having to twist a hose which supplies air to the device as is usual, the control sleeve is rigidly fixed in position in the housing and has control ports to which air is supplied or not under the control of valve members and which are themselves remotely controlled by a second compressed air supply to the device, or electrically.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.