Hydraulic shock absorber
US4067405A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 4, 1976 |
| Grant date | Jan 10, 1978 |
| Priority date | — |
| Expiry date | Oct 4, 1996 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B17/07
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An hydraulic shock absorber for protecting the drill bit and drill pipe in rotary earth drilling consists of a casing with an upper sub mounted in its one end for connection to a string of drill pipe. An anvil is slidably mounted on the other end. A plurality of hollow pistons are slidably mounted inside the casing. The pistons each have a hollow sleeve portion extending in sealing relationship through seating rings mounted on the inside of said casing. The pistons also have a radial flange portion at their upper end slidably sealing with the walls of the casing and a fluid passage extends through the wall of the casing between the flange portion and the seating ring.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.