3915244 is referenced by 132 patents and cites 5 patents.

Disclosed is a rotary drive assembly for manipulating well pipe. The assembly, which is carried in a drilling derrick, provides means for both threaded and non-threaded connection with a well pipe. The threaded connection is used for imparting rotary motion to the pipe and an attached drill string during drilling. A break out elevator provides non-threaded connection used for manipulating pipe members and for making up or breaking out a connection between threaded pipe segments. The elevator is pivotally suspended by bails from a rotary powering mechanism which may be raised or lowered in the derrick. Powered cocking means are provided for pivoting the bails as required to move the elevator laterally. Powered gripping means may be used in the elevator to selectively grip or release a pipe member extending through the elevator. Cam surfaces acting with the gripping means automatically increase the gripping forces exerted on the pipe member as the forces tending to move the pipe relative to the elevator increase. A lost motion connection is employed between the bails and the powering mechanism to provide a rotary jarring force to the pipe gripped by the elevator. Several modified gripping assemblies for use in the elevator are described.

Title
Break out elevators for rotary drive assemblies
Application Number
05/477,028
Publication Number
3915244
Application Date
June 6, 1974
Publication Date
October 28, 1975
Inventor
Brown deceased Cicero C
Agent
Torres & Berryhill
IPC
E21B 19/07
E21B 19/00
E21B 19/20
E21B 19/07
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