Contact detection system for power equipment

• US 8,186,255 B2
• Filed: 11/16/2009
• Issued: 05/29/2012
• Est. Priority Date: 09/29/2000
• Status: Expired due to Term

• Current Assignee: Sawstop Holding LLC
• Original Assignee: SD3, LLC
• Inventors: Gass, Stephen F., Fulmer, J. David
• Primary Examiner(s): Alie, Ghassem
• Application Number:
  US12/590,924
• Publication Number:
  US 20100132524A1
• Time in Patent Office: 925 Days
• Field of Search: 83/13, 83/621, 83D/IG.1, 833/97, 834/771, 834/713, 836/30, 833/971, 83/58, 832/97, 836/44, 834/712, 834/772, 834/90, 835/81, 324/678, 324/658, 324/686, 324/660, 324/725, 324/706, 317/146, 317/153, 317/123, 361/179
• US Class Current: 83/62.1
• 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 83/04 Processes
• 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 83/613 Work guard
• CPC Class Codes: Y10T 83/7693 Tool moved relative to work-support during cutting
• CPC Class Codes: Y10T 83/773 Work-support includes passageway for tool [e.g., slotted table]
• CPC Class Codes: Y10T 83/7763 Tool carrier reciprocable rectilinearly
• CPC Class Codes: Y10T 83/7788 Tool carrier oscillated or rotated
• CPC Class Codes: Y10T 83/8773 : Bevel or miter cut

Abstract

A woodworking machine having one or more dangerous portions is disclosed. The machine also includes a safety system configured to detect accidental contact between a person and at least one of the dangerous portions by electrically coupling a signal to the person'"'"'s body, and detecting if the signal becomes coupled to the dangerous portion.

Claims

1. A woodworking machine having one or more dangerous portions comprising:

means for generating an electrical signal;

means for coupling the electrical signal onto a person

means for monitoring at least one of the dangerous portions for the presence of electrical signals; and

means for detecting if the electrical signal coupled onto the person becomes coupled onto the at least one dangerous portion due to contact between the person and the at least one dangerous portion.

2. The machine of claim 1, further comprising cutting means configured to cut workpieces, and where the at least one dangerous portion is the cutting means.

3. The machine of claim 1, further comprising cutting means for cutting workpieces, and guard means for at least partially shielding the cutting means, and where the at least one dangerous portion is the guard means.

4. The machine of claim 1, further comprising means for coupling a detection signal onto the at least one dangerous portion.

5. The machine of claim 1, where the means for detecting includes means for detecting if the detection signal coupled onto the at least one dangerous portion changes due to the coupling of the electrical signal onto the at least one dangerous portion.

6. The machine of claim 1, where the electrical signal is a ground signal.

7. The machines of claim 1, where the electrical signal is an alternating signal.