Brake mechanism for power equipment

• US 7,661,343 B2
• Filed: 04/17/2007
• Issued: 02/16/2010
• Est. Priority Date: 10/01/1999
• Status: Expired due to Fees

• Current Assignee: Sawstop Holding LLC
• Original Assignee: SD3, LLC
• Inventors: Fanning, David A., Gass, Stephen F.
• Primary Examiner(s): Alie; Ghassem
• Application Number:
  US11/787,471
• Publication Number:
  US 20070186737A1
• Time in Patent Office: 1,036 Days
• Field of Search: 83/621, 834/772, 834/90, 83D/IG.1, 834/771, 834/713, 83/58, 834/78, 833/57, 833/98, 834/71, 835/26, 834/91, 835/01, 839/32, 833/971, 834/712, 835/81, 831/62, 831/56, 83/726, 83/731, 83/74
• US Class Current: 83/62.1
• 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: B26D 5/00 Arrangements for operating and controlling machines or devices for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
• CPC Class Codes: B26D 7/22 Safety devices specially adapted for cutting machines safety devices in general F16P
• 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 19/00 Safety guards or devices specially adapted for wood saws; Auxiliary devices facilitating proper operation of wood saws
• 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: F16P 3/148 using capacitive technology
• 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 83/613 Work guard
• CPC Class Codes: Y10T 83/7693 Tool moved relative to work-support during cutting
• CPC Class Codes: Y10T 83/7697 Tool angularly adjustable relative to work-support
• CPC Class Codes: Y10T 83/773 Work-support includes passageway for tool [e.g., slotted table]
• CPC Class Codes: Y10T 83/7734 With guard for tool
• CPC Class Codes: Y10T 83/7788 Tool carrier oscillated or rotated
• CPC Class Codes: Y10T 83/8773 Bevel or miter cut

Abstract

Brake pawls for use in safety systems for power equipment are disclosed. The brake pawls include an energy-absorbing region. The energy absorbing regions may include a deformable or collapsible region made from apertures in the brake pawl or from collapsible members or from materials of differing hardnesses, strengths, or structures.

Claims

1. A power tool comprising:

a moving cutting tool,

a safety system adapted to detect a dangerous condition between a person and the cutting tool, and

a brake pawl adapted to engage the cutting tool upon detection by the safety system of the dangerous condition,

where the brake pawl includes a contact region to engage the moving cutting tool and an energy-absorbing region to absorb at least some of the energy of the moving cutting tool by permanently deforming or collapsing when the contact region engages the moving cutting tool, where the energy-absorbing region is positioned not to make contact with the moving cutting tool when the contact region engages the moving cutting tool.

2. The power tool of claim 1 where the energy-absorbing region comprises at least one hole.

3. The power tool of claim 1 where the energy-absorbing region comprises holes.

4. The power tool of claim 1 where the brake pawl includes a mounting region distinct from the contact region and where the energy-absorbing region is nearer the mounting region than the contact region.

5. The power tool of claim 1 where the brake pawl includes a mounting region adapted to mount the brake pawl on a pin.

6. The power tool of claim 1 where the energy-absorbing region comprises an elongate aperture.

7. The power tool of claim 1 where the brake pawl includes a mounting region adapted to mount the brake pawl on a pin and where the energy-absorbing region comprises an aperture adjacent the mounting region.

8. The power tool of claim 1 where the brake pawl includes a mounting region and where the energy-absorbing region is between the contact region and the mounting region.

9. The power tool of claim 1 where the energy-absorbing region is shaped to deform or collapse.

10. The power tool of claim 1 where the energy absorbing region is shaped like a “

T”

with two ends, and where the where the two ends are adapted to mount in brackets.

11. The power tool of claim 1 where the energy-absorbing region is annealed aluminum.

12. The power tool of claim 1 where the contact region is annealed aluminum.

13. The power tool of claim 1 where the energy-absorbing region comprises at least one depression.

14. The power tool of claim 1 where the energy-absorbing region is structurally weaker than another region of the brake pawl.

15. The power tool of claim 1 where the contact region includes at least one hole and the energy-absorbing region comprises at least one hole.

16. The power tool of claim 1 where the contact region includes holes and the energy-absorbing region comprises at least one hole.

17. The power tool of claim 1 where the brake pawl includes a mounting region distinct from the contact region, where the contact region includes at least one hole, and the energy-absorbing region is between the contact region and the mounting region.

18. A power tool comprising:

a moving cutting tool,

a safety system adapted to detect a dangerous condition between a person and the cutting tool, and

a brake pawl adapted to engage the cutting tool upon detection by the safety system of the dangerous condition, where the brake pawl includes a contact region to engage the moving cutting tool and means for permanently deforming or collapsing to absorb at least some of the energy of the moving cutting tool when the contact region engages the moving cutting tool, where the means for permanently deforming or collapsing does not make contact with the moving cutting tool when the contact region engages the moving cutting tool.