Stewart Warner Corporation

Thor Power Tool Company

Francis G Bardwell

Edmund C Dudek

A pattern tracer with circuitry for electronically adjusting the lateral offset of the tracing element for kerf compensation, that produces a control signal based on a temporal relationship between a reference signal and a pattern detection signal associated with a preselected kerf compensation. The pattern is traced with the selected lateral offset in accordance with a control signal. The control signal is developed in response to both a line width compensation signal and a kerf compensation signal. A photometric detector is calibrated by electronically adding a compensation angle to a pattern detection angle to compensate for any physical misalignment of the detector.

Pattern tracer with electronic kerf, calibration and line width

This disclosure deals with a line or pattern following system for use with a machine including first and second motors for moving a device in first and second generally perpendicular directions. The system includes an array of light sensitive elements arranged at angularly juxtaposed positions, the array being positioned adjacent said line or pattern. An image of the line or pattern falls on the array and makes an angle .theta. with a reference point on the array. The system further includes means for sequentially scanning the outputs of the elements, and angle means responsive to said outputs and to said reference point for generating first and second signals. The first signal is a function of sin .theta. and is connected to control energization of the first motor, and the second signal is a function of cos .theta. and is connected to control energization of the second motor. The two motors, thus energized, produce relative motion of the array and the line or pattern, and move the array to follow the line or pattern.

Line or pattern following system

This disclosure deals with a control circuit for a tool including a motor for turning a rotatable power output shaft of the tool. A torque measuring device is coupled to the shaft and generates a signal which is a function of the torque output. The control circuit responds to the torque output and to a reference signal representing a preselected torque, and automatically turns off the motor when the torque output reaches the preselected torque. Further, the control circuit may cyclically turn the tool on and off at very short time intervals as the preselected torque value is being approached, in order to reduce the reaction torque felt by an operator of the tool. In addition, the lengths of the on times in successive cycles may be gradually decreased as the torque output level increases, with the result that the average reaction torque remains substantially constant even though the peak torque output increases.

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Elmhurst, IL, United States of America

Francis G Bardwell