Motion detecting system for use in a safety system for power equipment

• US 8,371,196 B2
• Filed: 11/07/2011
• Issued: 02/12/2013
• Est. Priority Date: 08/14/2000
• Status: Expired due to Term

• Current Assignee: Sawstop Holding LLC
• Original Assignee: SD3, LLC
• Inventors: Gass, Stephen F., Chamberlain, Robert L., Fulmer, J. David, Jensen, Joel F., Schramm, Benjamin B.
• Primary Examiner(s): Alie, Ghassem
• Application Number:
  US13/373,180
• Publication Number:
  US 20120125485A1
• Time in Patent Office: 463 Days
• Field of Search: 83/621, 835/221.2, 83/58, 83/62, 83/72, 83/767, 837/88, 835/81, 834/712, 834/771, 834/772, 835/26, 833/971, 835/221.21, 144/382, 144/356, 144/154.5, 144/384, 144/391, 144/286.5, 297/08, 292/54, 294/13, 324/550, 324/424, 408/5
• US Class Current: 83/62.1
• 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 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 3/141 using sound propagation, e.g. sonar
• CPC Class Codes: F16P 3/144 using light grids
• CPC Class Codes: F16P 3/145 using magnetic technology
• CPC Class Codes: F16P 3/147 using electro-magnetic technology, e.g. tags or radar
• CPC Class Codes: F16P 3/148 using capacitive technology
• CPC Class Codes: Y10S 83/01 Safety devices
• CPC Class Codes: Y10T 83/0319 Forming common groove
• 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 83/7697 Tool angularly adjustable relative to work-support
• CPC Class Codes: Y10T 83/7726 By movement of the tool
• CPC Class Codes: Y10T 83/85 Signal; e.g., alarm

Abstract

A method of controlling a woodworking machine having a movable cutting tool. The method monitors a signal for a change indicative of a dangerous condition between the cutting tool and a person, senses movement of the cutting tool, and performs an action to mitigate the dangerous condition when the signal change and movement of the cutting tool are both detected. A woodworking machine including a detection system adapted to detect a dangerous condition between a person and a working portion of the machine and then to perform some action to mitigate the dangerous condition is also disclosed. A motion detection system is adapted to detect motion of the working portion and to disable the reaction system when the working portion is not moving.

Claims

1. A woodworking machine comprising:

a working portion adapted to work when moving;

a detection system configured to detect a dangerous condition between a person and the working portion by monitoring an electric signal for at least one change indicative of the dangerous condition;

a reaction mechanism configured to perform a predetermined action relative to the working portion upon detection of the dangerous condition; and

means for detecting motion of the working portion and for disabling the reaction mechanism when the working portion is not moving.

2. The woodworking machine of claim 1, where the change indicative of the dangerous condition is not dependent on movement of the working portion.

3. The woodworking machine of claim 1, where the detection system is further configured to impart the electric signal to the cutting tool.