Motion detecting system for use in a safety system for power equipment
First Claim
1. A woodworking machine comprising:
- a cutter;
a motor adapted to drive the cutter;
a detection system adapted to detect a dangerous condition between a user and the cutter;
a reaction system adapted to perform a specified action to mitigate the dangerous condition upon detection of the dangerous condition by the detection system; and
a control system adapted to detect back emf produced by the motor as the motor coasts down after power has been removed from the motor, and where the control system is further adapted to permit the reaction system to perform the specified action during coast down of the motor only if back emf is detected.
2 Assignments
0 Petitions
Accused Products
Abstract
A woodworking machine including a detection system adapted to detect a dangerous condition between a person and a working portion of the machine is disclosed. The machine includes a reaction system associated with the detection system to cause a predetermined action to take place relative to the working portion upon detection of the dangerous condition. A motion detection system is adapted to detect motion of the working portion and to disable the reaction system when the working portion is not moving. The motion detection system may sense whether motion in a machine has stopped by monitoring the back emf produced on the motor leads as the motor coasts to a stop. The woodworking machine may take the form of a saw, the working portion may be a blade adapted to cut when spinning, and the dangerous condition may be a person contacting the blade.
116 Citations
20 Claims
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1. A woodworking machine comprising:
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a cutter;
a motor adapted to drive the cutter;
a detection system adapted to detect a dangerous condition between a user and the cutter;
a reaction system adapted to perform a specified action to mitigate the dangerous condition upon detection of the dangerous condition by the detection system; and
a control system adapted to detect back emf produced by the motor as the motor coasts down after power has been removed from the motor, and where the control system is further adapted to permit the reaction system to perform the specified action during coast down of the motor only if back emf is detected. - 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;
a motor adapted to drive the cutter;
a detection system adapted to detect a dangerous condition between a user and the cutter;
a reaction system adapted to perform a specified action to mitigate the dangerous condition upon detection of the dangerous condition by the detection system; and
a control system adapted to determine whether the cutter is moving by detecting back emf produced by the motor as the motor coasts down after power has been removed from the motor, and further adapted to deactivate the detection and/or reaction system if the cutter is not moving. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A woodworking machine comprising:
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a cutter;
a motor adapted to drive the cutter;
a detection system adapted to detect a dangerous condition between a user and the cutter;
a reaction system adapted to perform a specified action to mitigate the dangerous condition upon detection of the dangerous condition by the detection system; and
control means for detecting back emf produced by the motor as the motor coasts down after power has been removed from the motor, and for triggering the reaction system only if a dangerous condition is detected when a predetermined level of back emf is also detected. - View Dependent Claims (17, 18, 19, 20)
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Specification