RESIDUAL TORQUE ANALYZER
First Claim
1. A system for detecting fastener movement and measuring a residual torque in a fastener joint, comprising:
- a device for applying torque to a stationary fastener in a tightened state and measuring torque and angle of rotation, the device comprising a sensing system that includes—
a gyroscope operably coupled to the device and adapted to provide a signal corresponding to the angle of rotation of the device as it applies torque to the fastener, anda torque transducer operably coupled to the device and adapted to provide a signal corresponding to the torque applied to the fastener by the device; and
a computing unit in operable communication with the sensing system and adapted to receive the signal corresponding to an angle of rotation of the device and the signal corresponding to the torque applied to the fastener, and determine a torque at a time of initial movement of the fastener, wherein determining the time of initial movement of the fastener comprises determining a base torque, calculating a plurality of rates of change in torque over change in angle from torque and angle measurements based on the base torque, and calculating differences between the rates to detect fastener movement, thereby differentiating between sensed motion caused by flex and actual fastener rotation.
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Accused Products
Abstract
A system for detecting fastener movement and measuring a residual torque in a fastener joint, including a device for applying torque to a stationary fastener in a tightened state and measuring torque and angle of rotation. The device includes a sensing system that has a gyroscope that provides a signal corresponding to the angle of rotation of the device as it applies torque to the fastener, and a torque transducer that provides a signal corresponding to the torque applied to the fastener by the device. The device also includes a computing unit in communication with the sensing system and adapted to receive the signal corresponding to an angle of rotation of the device and the signal corresponding to the torque applied to the fastener, and determine a torque at a moment of initial movement of the fastener.
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Citations
20 Claims
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1. A system for detecting fastener movement and measuring a residual torque in a fastener joint, comprising:
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a device for applying torque to a stationary fastener in a tightened state and measuring torque and angle of rotation, the device comprising a sensing system that includes— a gyroscope operably coupled to the device and adapted to provide a signal corresponding to the angle of rotation of the device as it applies torque to the fastener, and a torque transducer operably coupled to the device and adapted to provide a signal corresponding to the torque applied to the fastener by the device; and a computing unit in operable communication with the sensing system and adapted to receive the signal corresponding to an angle of rotation of the device and the signal corresponding to the torque applied to the fastener, and determine a torque at a time of initial movement of the fastener, wherein determining the time of initial movement of the fastener comprises determining a base torque, calculating a plurality of rates of change in torque over change in angle from torque and angle measurements based on the base torque, and calculating differences between the rates to detect fastener movement, thereby differentiating between sensed motion caused by flex and actual fastener rotation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of measuring residual torque in a previously tightened fastener, comprising:
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applying torque to a previously tightened fastener using a device adapted to measure applied torque and angular motion; measuring torque applied to the fastener at a plurality of sensed angular positions to obtain a plurality of torque-angle data points; determining a base slope for at least one of the plurality of torque-angle data points, wherein the base slope comprises a change in torque over a change in angle for the at least one torque-angle data point as compared to a base point; determining a forward slope for the at least one torque-data point, wherein the forward slope comprises a change in torque over a change in angle for a point subsequent the at least one torque-angle data point and the at least one torque-angle data point; determining a slope delta for the at least one torque-angle data point, wherein the slope delta comprises a rate of change between the forward slope and the base slope; comparing the slope delta of the at least one torque-angle data point to a minimum slope delta, thereby obtaining an indication of a rate of change of torque per unit of angular motion of the at least one torque-angle data point as compared to the plurality of torque-angle data points. - View Dependent Claims (12, 13, 14, 15)
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16. A device for applying torque to a fastener, comprising:
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means for tightening a fastener in a fastener joint; means for sensing angular movement of the means for tightening and providing a signal corresponding to the angle of rotation of the tightening means as it applies tightens the fastener; means for sensing a torque applied to the fastener and providing a signal corresponding to the torque applied to the fastener by the means for tightening; and means for processing the signal corresponding to the angle of rotation and the signal corresponding to the torque applied to the fastener to determine a torque value corresponding to movement of the fastener. - View Dependent Claims (17, 18, 19, 20)
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Specification