Band saw with safety system

• US 7,621,205 B2
• Filed: 09/02/2005
• Issued: 11/24/2009
• Est. Priority Date: 10/01/1999
• Status: Expired due to Fees

• Current Assignee: Sawstop Holding LLC
• Original Assignee: SD3, LLC
• Inventors: Gass, Stephen F.
• Primary Examiner(s): Alie; Ghassem
• Application Number:
  US11/218,356
• Publication Number:
  US 20060000337A1
• Time in Patent Office: 1,544 Days
• Field of Search: 83/621, 83D/IG.1, 83/58, 834/71, 834/90, 835/81, 834/711, 834/772, 837/88, 836/10, 838/20, 838/29, 837/93, 837/90, 837/92
• US Class Current: 83/58
• CPC Class Codes: B23D 55/00 Sawing machines or sawing devices working with strap saw blades, characterised only by constructional features of particular parts constructional features of these parts per se B23Q
• 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 13/16 Accessories, e.g. for cooling the saw blade
• 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: B27G 19/06 for band or strap saws
• CPC Class Codes: B27G 21/00 Safety guards or devices specially designed for other wood-working machines auxiliary devices facilitating proper operation of said wood-working machines
• 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: G05B 19/4061 Avoiding collision or forbidden zones
• CPC Class Codes: G05B 2219/45044 Cutting
• CPC Class Codes: G05B 2219/49152 Feedhold, stop motion if machine door is open, if operator in forbidden zone
• CPC Class Codes: G05B 2219/49159 Avoid pinching of persons between moving and fixed part
• 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 83/707 By endless band or chain knife
• CPC Class Codes: Y10T 83/7083 With cutter other than endlessly orbiting type

Abstract

A band saw including 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 engage and stop the blade within 10 milliseconds after detection of the dangerous condition is disclosed. The reaction system may be configured to cut and grip the blade.

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 cut the blade upon detection of the dangerous condition.

2. The band saw of claim 1, where the reaction system is further configured to grip the blade upon detection of the dangerous condition.

3. The band saw of claim 1, where the reaction system includes a cutting element.

4. The band saw of claim 3, where the cutting element is configured to pivot against the blade.

5. The band saw of claim 4, where the cutting element is configured so that when it pivots against the blade, the normal motion of the blade tends to move the cutting element further against the blade.

6. The band saw of claim 3, where the cutting element is configured to both cut and grip the blade.

7. The band saw of claim 3, further comprising a spring to bias the cutting element toward the blade.

8. The band saw of claim 3, where the cutting element includes a cutting edge made of carbide or hardened steel.

9. The band saw of claim 3, further comprising a surface against which the cutting element cuts the blade.

10. The band saw of claim 9, where the surface is curved.

11. The band saw of claim 9, where the surface is a backing plate.

12. The band saw of claim 3, where the cutting element includes a cutting edge that extends helically away from the blade.

13. The band saw of claim 1, where the reaction system includes a cutting pawl pivotally mounted to the frame and configured to pivot into contact with the blade, where the cutting pawl is pivotally mounted to the frame at a point so that the pawl pushes the blade away from where the blade would normally cut when the pawl pivots into the blade.

14. The band saw of claim 1, where the reaction system includes two cutting pawls.

15. The band saw of claim 14, where one pawl is positioned on each side of the blade.

16. The band saw of claim 14, where the two cutting pawls are configured as scissors to cut the blade.

17. The band saw of claim 14, where the two cutting pawls are positioned so that they are not coplanar.

18. 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 cutting the blade upon detection of the dangerous condition.