Spring-biased brake mechanism for power equipment

• US 20020020271A1
• Filed: 08/13/2001
• Published: 02/21/2002
• Est. Priority Date: 08/14/2000
• Status: Active Grant

• Current Assignee: Sawstop Holding LLC
• Original Assignee: SD3, LLC
• Inventors: Gass, Stephen F., DʼAscenzo, David S.
• Granted Patent: US 7,308,843 B2
• Time in Patent Office: Days
• US Class Current: 83/477.2
• 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: 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: Y10T 83/04 Processes
• CPC Class Codes: Y10T 83/081 With randomly actuated stopping means
• CPC Class Codes: Y10T 83/083 With means to permit subsequent hand operation
• CPC Class Codes: Y10T 83/089 Responsive to tool characteristic
• CPC Class Codes: Y10T 83/536 Movement of work controlled
• CPC Class Codes: Y10T 83/613 Work guard
• CPC Class Codes: Y10T 83/7684 With means to support work relative to tool[s]
• 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 83/8773 Bevel or miter cut

Abstract

Woodworking machines are disclosed having cutting tools for cutting workpieces. The machines include a detection system adapted to detect one or more dangerous conditions between a person and the cutting tool. The machines also include at least one brake component adapted to engage and stop movement of the cutting tool, and an actuator adapted to move the brake component into contact with the cutting tool at a high acceleration when the detection system detects the dangerous condition between the person and the blade.

Claims

1. A woodworking machine comprising:

a support frame;

a motor supported by the frame;

a cutting tool supported by the frame and moveable by the motor;

a detection system adapted to detect contact between a person and the cutting tool;

a brake component adapted to engage and stop movement of the cutting tool, where the brake component has a ready position spaced apart from the cutting tool; and

an actuator having stored energy sufficient to move the brake component from the ready position into engagement with the cutting tool within approximately 3 milliseconds or less after contact between a person and the cutting tool is detected.

2. The machine of claim 1, where the cutting tool has one or more teeth, and where the brake component is adapted to engage the teeth of the cutting tool.

3. The machine of claim 1, where the actuator includes a spring adapted to move the brake component into engagement with the cutting tool within approximately 3 milliseconds or less.

4. The machine of claim 3, further comprising a housing removably coupled to the frame, where the spring and the brake component are mounted within the housing.

5. The machine of claim 3, where the cutting tool has one or more teeth, and where the spring is adapted to move the brake component into engagement with the teeth of the cutting tool within approximately 3 milliseconds or less.

6. The machine of claim 1, where the spacing between the brake component and the cutting tool is at least ⅛

-inch when the brake component is in the ready position.

7. The machine of claim 1, where the spacing between the brake component is and the cutting tool is at least ¼

-inch when the brake component is in the ready position.

8. A woodworking machine comprising:

a support structure;

a motor supported by the support structure;

a blade supported by the support structure and moveable by the motor;

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

a brake component adapted to engage and stop movement of the blade after such contact is detected by the detection system, where the brake component has a ready position spaced apart from the blade; and

an actuator adapted to move the brake from the ready position into contact with the blade at a high acceleration when the detection system detects contact between the person and the blade.

9. The machine of claim 8, where the actuator is adapted to move the brake at an acceleration of over 500 ft/s² when the detection system detects contact between the person and the blade.

10. The machine of claim 8, where the actuator is adapted to move the brake at an acceleration of over 2000 ft/s² when the detection system detects contact between the person and the blade.

11. The machine of claim 8, where the actuator includes one or more springs adapted to move the brake into contact with the blade.

12. The machine of claim 11, where the one or more springs are adapted to apply at least 50 lbs. of force to move the brake into contact with the blade.

14. The machine of claim 13, where the spring is compressed against the brake component when the second region is in the cocked position.

15. The machine of claim 14, where the spring is adapted to apply at least 50 lbs. of force against the brake component when the second region is in the cocked position.

16. The machine of claim 14, where the spring is adapted to apply at least 100 lbs. of force against the brake component when the second region is in the cocked position.

17. The machine of claim 13, where the spring is adapted to move the second region of the blade toward the blade at an acceleration of at least 500 ft/s² after the detection system detects contact between a person and the blade.

18. The machine of claim 13, where the spring is adapted to move the second region of the brake component into contact with the blade within 3 milliseconds or less after the detection system detects contact between a person and the blade.

13. A woodworking machine, comprising:

a support frame assembly;

a blade coupled to the support frame assembly and adapted to cut workpieces;

a motor coupled to the support frame assembly and adapted to drive the blade;

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

a reaction system coupled to the support frame assembly and adapted to stop movement of the blade upon detection of contact between a person and the blade by the detection system, where the reaction system includes;

a brake component having a first region pivotally coupled to the support frame assembly and a second region selectively movable into contact with the blade from a cocked position spaced-apart from the blade,

a spring configured to urge the second region of the brake component into contact with the blade from the cocked position, and

a restraining mechanism adapted to maintain the second region of the brake component in the cocked position against the urging of the spring until detection of contact between a person and the blade by the detection system.

19. A woodworking machine, comprising:

a cutting tool adapted to cut workpieces;

means for driving the cutting tool;

means for detecting contact between a person and the cutting tool;

a brake component spaced apart from the cutting tool; and

means for moving the brake component into contact with the cutting tool within 3 milliseconds or less after contact between a person and the cutting tool is detected.

20. A woodworking machine, comprising:

a cutting tool adapted to cut workpieces;

means for driving the cutting tool;

means for detecting contact between a person and the cutting tool;

a brake component selectively movable into contact with the cutting tool from a ready position spaced apart from the cutting tool; and

means for moving the brake component into contact with the cutting tool at an acceleration of over 2,000 ft/s² after contact between a person and the cutting tool is detected.