Rene A Chapelle

US Patent:

47154543, Dec 29, 1987

Filed:

Jun 3, 1986

Appl. No.:

6/870087

Inventors:

Chuan C. Teng - Houston TX
Rene A. Chapelle - Conroe TX
John E. Blacklaws - Houston TX
Lee E. McComsey - Anchorage AK

International Classification:

E21B 31107

US Classification:

175299

Abstract:

A drilling jar is disclosed. The jar has particular application in directional drilling operations and includes a swivel which allows the drilling jar to operate substantially independently of any right hand torque that becomes trapped in the drill string. The swivel includes a bearing cage that engages the polished stem of the drilling jar to the jay stem of the drilling jar. This bearing cage holds a number of bearings against the jay stem and the polished stem. The swivel allows the jay stem to rotate substantially independently of the polished stem. The drilling jar may further include splines formed onto the outer surface of the polished stem for transmitting torque from the polished stem to the barrel of the drilling jar without simultaneously transmitting torque from the polished stem to the jay stem. In addition, the drilling jar may include floating pistons that are circumferentially engaged to the polished stem and the washpipe that effect the upper and lower seals on the drilling jar and allow the internal pressure inside the tool to be equalized with the internal and external pressures of the drill string.