Safety systems for band saws

• US 20030019341A1
• Filed: 07/25/2002
• Published: 01/30/2003
• Est. Priority Date: 07/27/2001
• Status: Active Grant

• Current Assignee: Sawstop Holding LLC
• Original Assignee: SD3, LLC
• Inventors: Huebner, Randall J., Gass, Stephen F.
• Granted Patent: US 7,000,514 B2
• Time in Patent Office: Days
• US Class Current: 83/58
• 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 19/06 for band or strap saws
• CPC Class Codes: Y10S 83/01 Safety devices
• CPC Class Codes: Y10T 83/081 With randomly actuated stopping means
• CPC Class Codes: Y10T 83/707 By endless band or chain knife
• CPC Class Codes: Y10T 83/7095 With means to change to non-endlessly orbiting cutter

Abstract

Band saws with high-speed safety systems are disclosed. The band saws include a detection system adapted to detect a dangerous condition between a blade and a person. A reaction system performs a specified action such as stopping the blade upon detection of the dangerous condition.

Claims

1. A band saw comprising:

a frame;

at least two, spaced apart, rotatable wheels supported by the frame;

a blade looped around the wheels, where rotation of at least one wheel causes the blade to move around the wheels;

a detection system adapted to detect a dangerous condition between a person and the blade; and

a reaction system configured to sever the blade upon detection of the dangerous condition.

2. The band saw of claim 1, where the reaction system includes a first pawl adapted to pivot into contact with the blade, a cutting edge on the first pawl, and a second pawl against which the cutting edge presses to sever the blade.

3. The band saw of claim 2, where the cutting edge on the first pawl is carbide.

4. The band saw of claim 2, where the first pawl includes an arm, where the reaction system further includes a spring, and where the spring is adapted to push against the arm to bias the first pawl to pivot toward the blade.

5. The band saw of claim 4, where the spring is a torsion spring.

6. The band saw of claim 5, where the reaction system further includes a spring contact surface, and where the torsion spring is positioned between the arm of the first pawl and the spring contact surface.

7. The band saw of claim 4, where the reaction system further includes a restraint adapted to prevent the first pawl from pivoting into contact with the blade.

8. The band saw of claim 7, where the restraint is a fuse wire that engages the arm of the first pawl, and where the fuse wire is configured to be fused to release the first pawl.

9. The band saw of claim 8, where the reaction system further comprises an electrode having two conductive surfaces, and where the fuse wire loops around the arm of the first pawl and the electrode.

10. The band saw of claim 9, further comprising an insulator associated with the arm of the first pawl to insulate the fuse wire from the first pawl.

11. The band saw of claim 2, where the first pawl is positioned on one side of the blade, and the second pawl is positioned on the opposite side of the blade.

12. The band saw of claim 11, where the first and second pawls are pivotally mounted on a support plate.

13. The band saw of claim 11, further comprising a link having two ends, where one end of the link is pivotally connected to the first pawl and the other end of the link is pivotally connected to the second pawl.

14. The band saw of claim 13, where the link causes the second pawl to pivot toward the blade when the first pawl pivots toward the blade.

15. The band saw of claim 14, where the first and second pawls are configured so that when they contact the blade, the motion of the blade pulls the pawls together.

16. The band saw of claim 2, where the first pawl includes recesses to minimize the mass of the pawl.

17. The band saw of claim 1, where the reaction system includes a cutting pawl configured to pivot into contact with the blade, a spring biasing the cutting pawl toward the blade, a restraint adapted to prevent the cutting pawl from pivoting into contact with the blade until the detection system detects a dangerous condition, and a cocking mechanism adapted to facilitate the installation of the restraint.

18. The band saw of claim 17, where the cocking mechanism comprises a bolt adapted to compress the spring while the restraint is installed.

19. The band saw of claim 18, where the bolt is further adapted to limit the pivoting of the cutting pawl.

20. A band saw comprising:

a frame;

at least two, spaced apart, rotatable wheels supported by the frame;

a blade looped around the wheels, where rotation of at least one wheel causes the blade to move around the wheels;

a detection system adapted to detect a dangerous condition between a person and the blade; and

reaction means for severing the blade upon detection of the dangerous condition.