Control Scheme For Detecting And Preventing Torque Conditions In A Power Tool
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Abstract
A control scheme is provided for a power tool having a rotary shaft. The control scheme includes: monitoring rotational motion of the tool generally about a longitudinal axis of the shaft; detecting a condition of the tool based on the rotational motion of the tool; and controlling torque imparted to the shaft upon detecting the tool condition, where the torque is inversely related to an angular displacement of the tool about the longitudinal axis of the shaft.
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Citations
43 Claims
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1-24. -24. (canceled)
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25. A method for controlling operation of a power tool having a motor drivably coupled to a rotary shaft, comprising:
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monitoring rotational motion of the tool about a longitudinal axis of the rotary shaft using a rotational motion sensor disposed in the power tool; detecting rotational motion of the tool with respect to the longitudinal axis of the rotary shaft based on input from the rotational motion sensor and using a controller disposed in the power tool; and pulsing, in response to detecting rotational motion, torque imparted by the motor to the shaft. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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34. A method for controlling operation of a power tool having a motor drivably coupled to a rotary shaft, comprising:
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monitoring rotational motion of the tool about a longitudinal axis of the rotary shaft using a rotational motion sensor disposed in the power tool; computing angular displacement of the power tool about the axis of the rotary shaft based on input from the rotational motion sensor and using a controller disposed in the power tool; and pulsing torque imparted by the motor to the shaft when the angular displacement of the power tool exceeds a threshold, such that time between pulses enables the operator to regain control of the tool. - View Dependent Claims (35, 36, 37)
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38. A power tool comprising:
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a housing; an output shaft at least partially contained in the housing and configured to rotate about a longitudinal axis; a motor contained in the housing and drivably connected to the output shaft to impart rotary motion thereto; a rotational motion sensor arranged in the housing at a location spatially separated from the output shaft and operable to detect rotational motion of the housing about the longitudinal axis of the output shaft; and a controller configured in the housing to receive a signal indicative of rotational motion from the rotational motion sensor and operable to determine angular displacement of the housing in relation to a reference position from the signal, the controller electrically connected to the motor and operable to pulse torque imparted by the motor to the output shaft when the angular displacement of the housing exceeds a displacement threshold. - View Dependent Claims (39, 40, 41, 42, 43)
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Specification