Safety system for power equipment

• US 7,055,417 B1
• Filed: 09/29/2000
• Issued: 06/06/2006
• Est. Priority Date: 10/01/1999
• Status: Expired due to Term

• Current Assignee: Sawstop Holding LLC
• Original Assignee: SD3, LLC
• Inventors: Gass, Stephen F.
• Primary Examiner(s): ASHLEY, BOYER DOLINGER
• Application Number:
  US09/676,190
• Time in Patent Office: 2,076 Days
• Field of Search: 83/621, 83/58, 83D/IG.1, 835/267.2, 83/768, 834/712, 834/73, 833/97, 834/77, 83/1, 834/85, 834/87, 834/90, 834/91, 835/221.2, 835/44, 835/46, 835/64, 835/81, 835/90, 836/65, 83/767, 192/130, 192/129.R, 192/144, 192/148, 192/131.R, 192/131.H, 192/134, 192/133, 192/138, 340/679, 340/530, 340/540, 340/521.1, 340/573.1, 340/680, 340/538, 318/538, 318/362, 318/366, 318/454, 318/551, 318/491, 144/329, 144/363, 144/391, 144/401, 144/252, 144/420, 144/421, 144/356, 324/76.11, 324/672, 326/21, 411/3, 411/29, 411/390, 307/142, 307/114, 307/131, 56/104, 56/113, 303/82, 303/81
• 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 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 19/02 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: H01H 27/00 Switches operated by a removable member, e.g. key, plug or plate; Switches operated by setting members according to a single predetermined combination out of several possible settings combined with plug-and-socket connectors H01R13/70; with current-carrying plug H01R31/08
• CPC Class Codes: H01H 3/022 Emergency operating parts, e.g. for stop-switch in dangerous conditions
• CPC Class Codes: H01H 9/161 comprising light emitting elements
• CPC Class Codes: Y10S 83/01 Safety devices
• 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 83/175 With condition sensor
• CPC Class Codes: Y10T 83/178 Responsive to work
• 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 83/7788 Tool carrier oscillated or rotated

Abstract

Safety systems for power equipment are disclosed. The safety systems include a detection system adapted to detect contact between a person and a working portion of a machine, where the detection system is adapted to capacitively impart an electric charge on the working portion and to detect when that charge drops; and a reaction system associated with the detection system to cause a predetermined action to take place relative to the working portion upon detection of contact between the person and the working portion by the detection system. Machines equipped with safety systems are also disclosed, such as saws, jointers, etc. The machines include a working portion, such as a cutter or blade, a detection system adapted to detect a dangerous condition between a person and the working portion, and a reaction system associated with the detection system to cause a predetermined action to take place upon detection of the dangerous condition, such as a brake system to stop the working portion, a retraction system to retract the working portion, or a system to cover the working portion. The machines may include a control system adapted to control the operability of one or more of the working portion, the detection system and the reaction system.

Claims

1. A saw comprising:

a base configured to rest on a generally horizontal surface to support the saw during operation;

a work surface supported by the base above the generally horizontal surface on which a workpiece may be cut;

a rotatable blade adapted to cut a workpiece on the work surface, where the blade has an angular momentum when rotating;

an axis around which the blade rotates;

a motor to drive the blade;

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

a reaction system including a brake to decelerate the blade upon detection of the dangerous condition between the person and the blade, where the reaction system is configured to use at least a fraction of the angular momentum of the blade to generate a force tending to urge the axis around which the blade rotates away from the work surface when the brake decelerates the blade.

2. The saw of claim 1, where the brake is configured to stop the rotation of the blade.

3. The saw of claim 1, where the saw is a table saw, where the blade is adapted to extend at least partially up through the work surface, and where the reaction system tends to urge the axis around which the blade rotates downward relative to the work surface.

4. A woodworking machine comprising:

a base configured to rest on a generally horizontal surface to support the machine during operation;

a work surface supported by the base above the generally horizontal surface on which a workpiece may be cut;

a rotatable blade adapted to cut a workpiece on the work surface, where the blade has angular momentum when rotating;

an axis around which the blade rotates;

a motor to drive the blade;

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

a reaction system adapted to use at least a fraction of the angular momentum of the blade to generate a force tending to urge the axis around which the blade rotates away from the work surface upon the detection of the dangerous condition.

5. The woodworking machine of claim 4, where the woodworking machine is a table saw, where the support structure includes a table, where the reaction system is positioned below the table, and where the reaction system is adapted to urge the blade in a direction downward relative to the table.

6. The woodworking machine of claim 4, where the woodworking machine is a miter saw, and further comprising a support arm moveable relative to the base, where the blade is mounted on the support arm, and where the reaction system is adapted to urge the blade upward relative to the base.

7. The woodworking machine of claim 4, where the reaction system is further adapted to stop the blade.

8. A miter saw comprising:

a support structure having a cutting zone;

a swing arm above and pivotally attached to the support structure;

a rotatable blade supported by the swing arm so that the blade may move into the cutting zone, where the blade has angular momentum when rotating;

a handle associated with the swing arm and adapted so that a user may pivot the swing arm and blade into the cutting zone;

a motor adapted to drive the blade;

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

a reaction system adapted to create an impulse against movement of the blade into the cutting zone upon detection by the detection system of the dangerous condition between the person and the blade, where the impulse is created due at least partially to the angular momentum of the blade.

9. The miter saw of claim 8, where the reaction system includes a brake mechanism adapted to engage the blade, and where the engagement of the brake mechanism with the blade creates the impulse against movement of the blade into the cutting zone.

10. A woodworking machine comprising:

a frame adapted to support workpieces in a cutting region;

a movable cutting tool supported by the frame and configured to cut workpieces in the cutting region;

a motor configured to drive the cutting tool;

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

a brake mechanism including at least one braking component configured to engage the cutting tool upon detection of at least one of the dangerous conditions by the detection system, where engagement of the braking component with the cutting tool tends to urge the cutting tool in a direction away from the cutting region.

11. A woodworking machine comprising:

a frame adapted to support workpieces in a cutting region;

a movable cutting tool supported by the frame and configured to cut workplaces in the cutting region;

a motor configured to drive the cutting tool;

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

a brake mechanism including at least one braking component configured to engage the cutting tool upon detection of at least one of the dangerous conditions by the detection system, where engagement of the braking component with the cutting tool tends to urge the cutting tool in a direction away from the cutting region, where the rotating cutting tool has angular momentum, and where the braking component is configured to transform at least a portion of the angular momentum of the cutting tool into a force on the cutting tool in a direction away from the cutting region.