Actuators for use in fast-acting safety systems

• US 7,712,403 B2
• Filed: 07/02/2002
• Issued: 05/11/2010
• Est. Priority Date: 07/03/2001
• Status: Active Grant

• Current Assignee: Sawstop Holding LLC
• Original Assignee: SD3, LLC
• Inventors: Fanning, David A., Gass, Stephen F.
• Primary Examiner(s): Nguyen; Danny
• Application Number:
  US10/189,027
• Publication Number:
  US 20030005588A1
• Time in Patent Office: 2,870 Days
• Field of Search: 361 23- 25, 361 29- 33, 83/58, 834/53, 834/90, 835/26, 80/58, 804/53, 804/90
• US Class Current: 83/58
• CPC Class Codes: B23D 51/166 Devices for arresting movement of the saw blades B23D51/20 takes precedence
• CPC Class Codes: B23D 59/001 Measuring or control devices, e.g. for automatic control of work feed pressure on band saw blade measuring in general G01; controlling in general G05
• CPC Class Codes: B27B 13/14 Braking devices specially designed for band sawing machines, e.g. acting after damage of the band saw blade
• CPC Class Codes: B27B 5/38 Devices for braking the circular saw blade or the saw spindle; Devices for damping vibrations of the circular saw blade, e.g. silencing B23D47/005 takes precedence
• CPC Class Codes: F16P 3/12 with means, e.g. feelers, which in case of the presence of a body part of a person in or near the danger zone influence the control or operation of the machine F16P3/08 takes precedence
• CPC Class Codes: Y10T 83/081 With randomly actuated stopping means
• CPC Class Codes: Y10T 83/8694 With brake or blocking means

Abstract

Cutting machines with high-speed safety systems, and actuators used in high-speed safety systems, are disclosed. The cutting machines may include a detection system adapted to detect a dangerous condition between a cutting tool and a person. A reaction system performs a specified action, such as stopping the cutting tool, upon detection of the dangerous condition. An actuator may be used to trigger the reaction system to perform the specified action.

Claims

1. An actuator for use in a safety system for a power tool, where the power tool includes a moving cuffing element, and where the safety system includes a brake member configured to move into contact with the cutting element to stop movement of the cutting element, the actuator comprising:

a spring adapted to expand to move the brake member into contact with the cutting element,

a restraining mechanism adapted to hold the spring in compression so that the spring is constrained from moving the brake member into contact with the culling element, and

a releasing mechanism configured to provide a movement to release the restraining member so the spring can expand to move the brake member into contact with the cutting element.

2. The actuator of claim 1, where the spring is a torsion spring.

3. The actuator of claim 1, where the releasing mechanism includes a solenoid.

4. The actuator of claim 1, where the releasing mechanism includes a voice coil.

5. The actuator of claim 1, where the releasing mechanism includes a shape memory alloy.

6. The actuator of claim 1, where the releasing mechanism includes an integrated force array.

7. The actuator of claim 1, where the restraining mechanism includes at least one pivot arm.

8. The actuator of claim 1, where the restraining mechanism includes a plurality of pivot arms.

9. The actuator of claim 1, where the releasing mechanism is within a housing.

10. An actuator for use in a safety system for a power tool, where the power tool includes a moving cutting element, and where the safety system includes a brake member configured to move into contact with the cutting element to stop movement of the cutting element, the actuator comprising:

stored force means for moving the brake member into the cutting element,

restraining means for constraining the stored force means from moving the brake member into the cutting element, and

release means for providing a movement to release the stored force means.