Electronic control circuitry for a nutrunner
Patent 4987806 Issued on January 29, 1991. Estimated Expiration Date: 
August 15, 2010. 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.
August 15, 2010. 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 ReferencesElectronic torque wrench Power-wrench, a boiling spindle and an operational method Patent #: 4813312 InventorApplicationNo. 568537 filed on 08/15/1990US Classes:81/469, Means for regulating motor73/862.23, With detection of specific torque value or condition (e.g., peak torque)173/180, With torque indicator173/182Strain gaugeExaminersPrimary: Smith, James G.Attorney, Agent or FirmInternational ClassB25B 023/151AbstractGenerally there is provided a nutrunner appliance for automatically driving a nut having an electrical motor, gearing, and a strain gauge to monitor the applied torque. The control system employs analog comparator circuits acting on analog signals from the strain gauge to determine the torque being applied. During operation, the comparator detects a predetermined torque and shifts the motor to a lower velocity to lower the inertia of the system. When the strain gauge output corresponds to the desired final torque, a braking action is applied to the motor to quickly terminate the applied torque. | |
