ApplicationNo. 07/074143 filed on 07/16/1987
US Classes:81/57.18, Cam-operated jaw81/57.15Round work
ExaminersPrimary: Meislin, D. S.
Attorney, Agent or Firm
International ClassesB25B 13/00 (20060101)
B25B 13/50 (20060101)
B25B 5/00 (20060101)
B25B 5/16 (20060101)
B25B 5/14 (20060101)
E21B 19/00 (20060101)
E21B 19/16 (20060101)
AbstractAn improvement is made to jaw designs for power tongs and back-up units. The jaw is formed having a cavity whose opening is oriented toward the pipe to be gripped. An elongated die is movably mounted in the cavity effectively closing off the cavity. The die has a gripping surface adapted to contact the pipe. A resilient member, preferably synthetic rubber or other elastomer or a substantially incompressible fluid, is disposed within the cavity adjacent the die. Uneven loads on the die are redistributed through the hydraulic action of the resilient member with a resultant equal distribution of the loads on the die.