Safety systems for power equipment

• US 20060123960A1
• Filed: 02/13/2006
• Published: 06/15/2006
• Est. Priority Date: 08/13/2001
• Status: Abandoned Application

• Current Assignee: SD3, LLC
• Original Assignee: SD3, LLC
• Inventors: McDonald, Anwyl M., D'Ascenzo, David S., Jensen, Joel F., Fanning, David A., Gass, Stephen F., Fulmer, J. David, Johnston, Andrew L., Kim, Sung H., Schramm, Benjamin B., Chamberlain, Robert L., Betts-LaCroix, Jonathan N.
• Application Number:
  US11/353,423
• Publication Number:
  US 20060123960A1
• Time in Patent Office: Days
• US Class Current: 83/13
• 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 vibration-damping of sawing machines or devices working with circular saw blades B23D47/005
• CPC Class Codes: B27G 19/02 for circular saws
• 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: Y10S 83/01 Safety devices
• CPC Class Codes: Y10T 83/04 Processes
• CPC Class Codes: Y10T 83/081 With randomly actuated stopping means
• CPC Class Codes: Y10T 83/089 Responsive to tool characteristic
• CPC Class Codes: Y10T 83/141 With means to monitor and control operation [e.g., self-regulating means]
• CPC Class Codes: Y10T 83/7697 Tool angularly adjustable relative to work-support
• CPC Class Codes: Y10T 83/7705 Adjustable angular relationship
• CPC Class Codes: Y10T 83/7726 By movement of the tool
• CPC Class Codes: Y10T 83/773 Work-support includes passageway for tool [e.g., slotted table]
• CPC Class Codes: Y10T 83/778 And means to rotate tool
• CPC Class Codes: Y10T 83/7788 Tool carrier oscillated or rotated
• CPC Class Codes: Y10T 83/8773 Bevel or miter cut

Abstract

A saw with a safety system is disclosed. The safety system includes a detection system adapted to detect contact between a person and a blade while the blade is moving. The safety system further includes a brake system adapted to engage the blade and to stop the blade when the detection system detects contact between the person and the blade.

Claims

1. A method of operating a saw comprising:

providing a blade configured to move to cut a work piece, where the blade includes a cutting edge;

providing a motor adapted to move the blade;

providing a detection system adapted to detect a dangerous condition between a person and the blade while the blade is moving and to distinguish that dangerous condition from proximity between green wood and the blade by imparting a signal to the blade and monitoring that signal for a predetermined change indicative of the dangerous condition;

providing a reaction system adapted to take some action to mitigate possible injury if the detection system detects the dangerous condition; and

moving the blade to cut a work piece while the detection and reaction systems are active.

2. The method of claim 1, where the dangerous condition is contact between a person and the blade.

3. The method of claim 1, where the dangerous condition is proximity between a person and the blade.

4. The method of claim 1, where the predetermined change indicative of the dangerous condition is a predetermined rate of change.

5. The method of claim 1, where the reaction system includes a retraction mechanism to retract the blade.

6. The method of claim 1, where the reaction system includes a brake to decelerate the blade.

7. The method of claim 6, where the brake includes a pawl and a system to move the pawl into contact with the blade.

8. The method of claim 7, where the system to move the pawl into contact with the blade causes the pawl to contact the blade within 10 milliseconds after the detection system detects the dangerous condition.

9. The method of claim 1, where the saw is a table saw.

10. The method of claim 1, where the saw is a miter saw.

11. The method of claim 1, where the saw is a hand-held circular saw.

12. A method of operating a saw comprising:

providing a blade configured to move to cut a work piece, where the blade includes a cutting edge;

providing a motor adapted to move the blade;

providing a detection system adapted to detect a dangerous condition between a person and the blade while the blade is moving and to distinguish that dangerous condition from contact between green wood and the blade by imparting a signal to the blade and monitoring that signal for a predetermined change indicative of the dangerous condition;

providing a reaction system adapted to take some action to mitigate possible injury if the detection system detects the dangerous condition; and

moving the blade to cut a work piece while the detection and reaction systems are active.

13. The method of claim 12, where the dangerous condition is contact between a person and the blade.

14. The method of claim 12, where the dangerous condition is proximity between a person and the blade.

15. The method of claim 12, where the predetermined change indicative of the dangerous condition is a predetermined rate of change.

16. The method of claim 12, where the reaction system includes a retraction mechanism to retract the blade.

17. The method of claim 12, where the reaction system includes a brake to decelerate the blade.

18. The method of claim 12, where the saw is a table saw.

19. The method of claim 12, where the saw is a miter saw.

20. The method of claim 12, where the saw is a hand-held circular saw.