Jaws for power tongs and back-up units
Patent 4836064 Issued on June 6, 1989. Estimated Expiration Date: 
July 16, 2007. 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.
July 16, 2007. 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 References Re31699 Re31993 1811666 2668689 3589742 3599960 3776320 3858468 Pipe closure apparatus Power tongs InventorApplicationNo. 07/074143 filed on 07/16/1987US Classes:81/57.18, Cam-operated jaw81/57.15Round workExaminersPrimary: Meislin, D. S.Attorney, Agent or FirmInternational 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. | |
