Tightening system
Patent 4008773 Issued on February 22, 1977. Estimated Expiration Date: 
February 22, 1994. 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.
February 22, 1994. 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 3368396 3643501 3693726 3710874 InventorsAssigneeApplicationNo. 579109 filed on 05/19/1975US Classes:173/181, Having torque sensor73/761, Threaded fastener stress73/862.24Rate of changeExaminersPrimary: Purser, Ernest R.Assistant: Pate, III, William F. Attorney, Agent or FirmAbstractThe preferred embodiments of the invention disclosed herein relate to a tightening system comprising a wrench for rotating and applying torque to a fastener system, means for developing a signal representative of the torque being applied and means for developing a signal representative of the rotation. A control system is operatively associated with the wrench for determining which of the two signals is increasing faster. If the torque signal is increasing faster than the rotation signal, the control system modifies the rotation signal by increasing it until it corresponds to the torque signal, but cannot decrease the modified rotation signal when the increase of the torque signal is less than the increase of the rotation signal. When the increase of the torque signal decreases relative to the modified rotation signal, the control system develops a decision-making signal which is processed to develop a control signal when a yield point of the fastener system is detected. | |
