| US 7,481,140 B2 | ||
| Detection systems for power equipment | ||
| Stephen F. Gass, Wilsonville, Oreg. (US); Paul J. Lingane, Redwood City, Calif. (US); and Arjuna R. Karunaratne, Fremont, Calif. (US) | ||
| Assigned to SD3, LLC, Tualatin, Oreg. (US) | ||
| Filed on Apr. 15, 2005, as Appl. No. 11/107,499. | ||
| Prior Publication US 2006/0247795 A1, Nov. 02, 2006 | ||
| Int. Cl. B26D 7/24 (2006.01); H02P 7/00 (2006.01) | ||
| U.S. Cl. 83—76 [83/58; 83/62.1; 83/471; 83/471.3; 83/477.2; 318/469; 340/660] | 9 Claims |
| 1. A woodworking power tool, comprising:
a motor;
a cutting tool driven by the motor; and
a safety system configured to detect a dangerous condition between a user and the cutting tool and to take some action to
reduce the danger to the user in the event a dangerous condition is detected, where the safety system includes a motor control
system with at least one electrical control line configured to selectively block operation of the motor, where the electrical
control line is configured so that it can be set to a high voltage or a low voltage by the control system, further wherein
the operation of the motor is blocked if the electrical control line is set either high or low and enabled only so long as
the electrical control line is toggled back and forth between high and low voltages.
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