Detection systems for power equipment
First Claim
Patent Images
1. A woodworking machine comprising:
- a cutter adapted to move to cut a workpiece;
a motor configured to move the cutter;
a safety system operatively associated with the cutter and configured to detect a dangerous condition between a user and the cutter, where the safety system includes a controller; and
a motor control system configured to selectively turn the motor on and off;
where the motor control system is controlled by the safety system, and where the controller in the safety system signals the motor control system to turn the motor off upon detection of the dangerous condition;
where the motor control system includes a motor control circuit adapted with at least one control input, and where the motor control circuit is configured to turn the motor on only upon receipt of a non-constant signal from the controller on the control input; and
where the controller is located remotely from the motor control system and operatively coupled to the motor control system by a cable.
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Abstract
Methods to detect when a human body contacts a predetermined portion of a machine are disclosed. The methods distinguish contact with a person from contact with other materials. The methods are particularly applicable in woodworking equipment such as table saws to distinguish contact between a person and the blade of the saw from contact between the blade and wet or green wood. The methods and woodworking equipment may include predictive blade stop algorithms that prevent unnecessary activations of a safety brake during coast down of a blade and continued protection in the event a main power switch is turned off.
30 Citations
11 Claims
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1. A woodworking machine comprising:
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a cutter adapted to move to cut a workpiece; a motor configured to move the cutter; a safety system operatively associated with the cutter and configured to detect a dangerous condition between a user and the cutter, where the safety system includes a controller; and a motor control system configured to selectively turn the motor on and off; where the motor control system is controlled by the safety system, and where the controller in the safety system signals the motor control system to turn the motor off upon detection of the dangerous condition; where the motor control system includes a motor control circuit adapted with at least one control input, and where the motor control circuit is configured to turn the motor on only upon receipt of a non-constant signal from the controller on the control input; and where the controller is located remotely from the motor control system and operatively coupled to the motor control system by a cable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A woodworking machine comprising:
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a cutter adapted to rotate to cut a workpiece; a motor configured to rotate the cutter; a safety system operatively associated with the cutter and configured to detect a dangerous condition between a user and the cutter, a reaction system configured to take some action to protect the user upon detection of the dangerous condition; and a rotation sensing system configured to sense rotation of the cutter, where the rotation sensing system receives discontinuous indications of rotation and is coupled to send a signal to the safety system to prevent action by the reaction system when the cutter stops rotating, where the rotation sensing system is configured to predict the time the cutter stops rotating by extrapolation of the discontinuous indications of rotation. - View Dependent Claims (10, 11)
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Specification