Keszthelyi

On November 20,1923, letters patent No. 1,474,905 were issued to plaintiff for a new and useful improvement in tool joints used in rotary drilling of oil wells.

Plaintiff explains in his specifications that in rotary drilling the bit cutting the formation is carried at the lower end of the string of drill pipe. To withdraw the bit it is necessary to pull the drill pipe, uncoupling it at intervals, ordinarily of four lengths of the pipe. As the pipe is drawn from the well it is therefore uncoupled at every fourth joint, and it is therefore necessary to provide a tool joint at such.intervals to prevent the injuring of the threads of the pipe by frequent coupling and uncoupling.

That in rotary drilling it is necessary to circulate a stream of mud-laden fluid down through the string of drill pipe and through the bit. To do this it is necessary to apply considerable pressure to the upper end of the drill pipe, and it is difficult, using the present type of tool joint, to insure tight joints at the ends of the stands of drill pipe.

That tool joints, as ordinarily constructed, consist of a pair of steel collars, one of which is screwed upon each of the contacting ends of the drill…