ApplicationNo. 067216 filed on 05/26/1993
US Classes:81/57.34, With additional work-engaging means81/57.16, With additional work-engaging means81/57.36Multiple work-engaging means
ExaminersPrimary: Smith, James G.
Attorney, Agent or Firm
Foreign Patent References
International ClassB25B 013/50
AbstractApparatus for making and breaking joints in drill pipe strings has three jaws each of which is adjustable to an infinite number of settings. The jaw-adjustment means are symmetrical about a central plane, and incorporate a spherical section. Different portions of the spherical section operate relative to closing and self-energizing of each jaw, the particular operative portion depending upon the exact set or adjusted position of the jaw. Each jaw is constructed for stable clamping of a drill type portion, with only one side of each jaw having a die element that is rotatably mounted. The jaw-adjustment mechanism effects both opening and closing of the jaw, there being no necessity to manually pull on a jaw portion at any time.