Apparatus for making and breaking joints in drill pipe strings
Patent 5386746 Issued on February 7, 1995. Estimated Expiration Date: 
May 26, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
May 26, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesInventorApplicationNo. 067216 filed on 05/26/1993US Classes:81/57.34, With additional work-engaging means81/57.16, With additional work-engaging means81/57.36Multiple work-engaging meansExaminersPrimary: Smith, James G.Attorney, Agent or FirmForeign Patent References
International ClassB25B 013/50AbstractApparatus 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. | |
