Miter saw with improved safety system

• US 20020059855A1
• Filed: 01/16/2002
• Published: 05/23/2002
• Est. Priority Date: 09/29/2000
• Status: Active Grant

• Current Assignee: Sawstop Holding LLC
• Original Assignee: SD3, LLC
• Inventors: Fanning, David A., Gass, Stephen F.
• Granted Patent: US 6,880,440 B2
• Time in Patent Office: Days
• US Class Current: 83/62
• CPC Class Codes: B23D 45/06 with a circular saw blade arranged underneath a stationary work-table
• CPC Class Codes: B23D 47/08 of devices for bringing the circular saw blade to the workpiece or removing same therefrom
• CPC Class Codes: B23D 55/08 of devices for guiding or feeding strap saw blades
• 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: Y10S 83/01 Safety devices
• CPC Class Codes: Y10T 74/1406 with safety device or drive disconnect
• CPC Class Codes: Y10T 83/081 With randomly actuated stopping means
• CPC Class Codes: Y10T 83/088 Responsive to tool detector or work-feed-means detector
• CPC Class Codes: Y10T 83/089 Responsive to tool characteristic
• CPC Class Codes: Y10T 83/7697 Tool angularly adjustable relative to work-support
• CPC Class Codes: Y10T 83/7726 By movement of the tool
• CPC Class Codes: Y10T 83/7788 Tool carrier oscillated or rotated
• CPC Class Codes: Y10T 83/8773 Bevel or miter cut
• CPC Class Codes: Y10T 83/8786 Oscillating tool

Abstract

A miter saw having a base and an arm that pivots toward the base is disclosed. A blade is supported by the arm, and is designed to cut workpieces resting on the base when the arm and blade pivot downward. The saw includes a detection system configured to detect one or more dangerous conditions between a person and the blade, such as when a person accidentally touches the spinning blade, and the saw includes a reaction system to stop the downward movement of the blade and arm when the dangerous condition is detected.

Claims

1. A miter saw comprising:

a base assembly defining a cutting zone and configured to support workpieces in the cutting zone;

a pivot arm coupled to the base assembly and selectively moveable toward and away from the cutting zone;

a motor assembly;

a rotatable arbor supported by the pivot arm and driven by the motor assembly;

a rotatable blade mounted on the arbor and configured to cut workpieces supported within the cutting zone;

a detection system configured to detect one or more dangerous conditions between a person and the blade; and

a reaction system configured to stop movement of the pivot arm toward the base assembly upon detection by the detection system of the one or more dangerous conditions.

2. The miter saw of claim 1, further comprising a rotatable platen adjacent the base assembly.

3. The miter saw of claim 1, where the reaction system is configured so that the pivot arm moves no more than one-eighth of an inch toward the base assembly after the detection system detects the one or more dangerous conditions.

4. The miter saw of claim 1, where the reaction system is configured to stop the movement of the pivot arm toward the base assembly within 10 milliseconds.

5. The miter saw of claim 1, further comprising a tilt mechanism between the base assembly and the pivot arm, where the tilt mechanism is configured so that the pivot arm may tilt relative to the base assembly.

6. The miter saw of claim 5, where the reaction system comprises a brace member and a locking assembly;

where the brace member is coupled to the tilt mechanism and the locking assembly;

where the locking assembly is coupled to the pivot arm; and

where the locking assembly is configured to lock onto the brace member to prevent the pivot arm from moving toward the base assembly when the detection system detects the one or more dangerous conditions between a person and the blade.

7. The miter saw of claim 6, where the reaction system further comprises a positioning mechanism associated with the brace member and locking assembly and configured to reduce any play in the brace member and locking assembly.

8. The miter saw of claim 7, where the positioning mechanism comprises a spring.

9. The miter saw of claim 6, where the brace member is slidably coupled to the locking assembly, and where the locking assembly comprises a gripping mechanism configured to selectively engage and grip the brace member.

10. The miter saw of claim 9, where the gripping mechanism comprises a clamping device;

and where the locking assembly further comprises a biasing mechanism configured to urge the clamping device to a locked position, and a restraining mechanism configured to maintain the clamping device in a nominal position until the detection system detects the one or more dangerous conditions.

11. The miter saw of claim 10, where the restraining mechanism comprises a fusible member.

12. The miter saw of claim 1, where the reaction system comprises a brace member and a locking assembly;

where the brace member is coupled to the base assembly and the locking assembly;

where the locking assembly is coupled to the pivot arm; and

where the locking assembly is configured to lock onto the brace member to prevent the pivot arm from moving toward the base assembly when the detection system detects the one or more dangerous conditions between a person and the blade.

13. The miter saw of claim 12, where the brace member is slidably coupled to the locking assembly, and where the locking assembly comprises a gripping mechanism configured to selectively engage and grip the brace member.

14. The miter saw of claim 13, where the gripping mechanism comprises a clamping device;

and where the locking assembly further comprises a biasing mechanism configured to urge the clamping device to a locked position, and a restraining mechanism configured to maintain the clamping device in a nominal position until the detection system detects the one or more dangerous conditions.

15. The miter saw of claim 14, where the restraining mechanism comprises a fusible member.

16. The miter saw of claim 1, where the reaction system is further configured to stop the rotation of the blade upon detection by the detection system of the one or more dangerous conditions.

17. A miter saw comprising:

a base assembly defining a cutting zone and configured to support workpieces in the cutting zone;

at least one rail extending outward from the base assembly;

a pivot arm slidably mounted on the at least one rail, where the pivot arm is configured to pivot downwardly toward the base assembly and to slide on the at least one rail toward the base assembly;

a motor assembly;

a rotatable arbor supported by the pivot arm and driven by the motor assembly;

a rotatable blade mounted on the arbor and configured to cut workpieces supported within the cutting zone;

a detection system configured to detect one or more dangerous conditions between a person and the blade; and

a reaction system configured to stop the pivoting and sliding of the pivot arm toward the base assembly upon detection by the detection system of the one or more dangerous conditions.

18. A miter saw comprising:

a base assembly defining a cutting zone and configured to support workpieces in the cutting zone;

a pivot arm coupled to the base assembly and selectively moveable toward and away from the cutting zone;

a motor assembly;

a rotatable arbor supported by the pivot arm and driven by the motor assembly;

a rotatable blade mounted on the arbor and configured to cut workpieces supported within the cutting zone;

a detection system configured to detect one or more dangerous conditions between a person and the blade; and

reaction means for stopping movement of the pivot arm toward the base assembly upon detection by the detection system of the one or more dangerous conditions.