Method and apparatus for fastener tensioning
Patent 4106176 Issued on August 15, 1978. Estimated Expiration Date: 
April 6, 1997. 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.
April 6, 1997. 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 2756622 Tightening system Yield torque apparatus Patent #: 4026369 InventorsApplicationNo. 05/785026 filed on 04/06/1977US Classes:29/407.03, Determining relative number of threaded member rotations173/182, Strain gauge702/43, Torsional, shear, tensile, or compression73/761Threaded fastener stressExaminersPrimary: Ruehl, Charles A.Attorney, Agent or FirmInternational ClassesB25B 23/14 (20060101)G05D 17/00 (20060101) G05D 17/02 (20060101) AbstractA fastener tensioning method and apparatus for obtaining a desired degree of tension in a fastener. The embodiment of this invention described utilizes the slope of the change in torque per change in rotation gradient to predict a rotation starting point independent of the rotation that occured in the torquing cycle up to the point of establishing a constant gradient. In the constant slope or gradient area of the torque rotation curve, rotation is considered linearly proportional to the tension in the fastener. A prescribed additional rotation is applied to the fastener utilizing the threads as a micrometer device for stretching the bolt to achieve the desired tension or fastener strain level. With appropriate system monitoring such as the total rotation, the maximum torque applied, the gradient slope, etc., the system can be adapted to inspect the fastener for applied tension as well as accurately control tension level. | |
