Detection systems for power equipment

• US 8,087,438 B2
• Filed: 05/03/2010
• Issued: 01/03/2012
• Est. Priority Date: 12/31/2003
• Status: Active Grant

• Current Assignee: Sawstop Holding LLC
• Original Assignee: SD3, LLC
• Inventors: Gass, Stephen F.
• Primary Examiner(s): Kasenge, Charles
• Application Number:
  US12/799,915
• Publication Number:
  US 20110061769A1
• Time in Patent Office: 610 Days
• Field of Search: 700/21, 700/79, 700/177, 83/72, 83/79, 702/65, 702/187, 318/445, 144/427, 144/382, 144/383, 173/1
• US Class Current: 144/382
• CPC Class Codes: B23D 45/067 the saw blade being adjustable according to depth or angle of cut
• CPC Class Codes: B23D 47/025 of tables
• 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: B23D 59/006 for removing or collecting chips
• 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 19/02 for circular saws
• CPC Class Codes: B27G 19/06 for band or strap saws
• CPC Class Codes: B27G 19/08 Accessories for keeping open the saw kerf, e.g. riving knives or wedge plates
• 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 83/141 With means to monitor and control operation [e.g., self-regulating means]
• CPC Class Codes: Y10T 83/704 With work-support and means to vary relationship between tool and work support
• CPC Class Codes: Y10T 83/7688 Plural tool elements successively actuated at same station
• CPC Class Codes: Y10T 83/7693 Tool moved relative to work-support during cutting
• CPC Class Codes: Y10T 83/7697 Tool angularly adjustable relative to work-support
• CPC Class Codes: Y10T 83/7705 Adjustable angular relationship
• 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 83/7793 : Means to rotate or oscillate tool
• CPC Class Codes: Y10T 83/8773 : Bevel or miter cut

Abstract

Methods to detect when a human body contacts a predetermined portion of a machine are disclosed. The methods distinguish contact with a person from contact with other materials. The methods are particularly applicable in woodworking equipment such as power saws to distinguish contact between a person and the blade of the saw from contact between the blade and wet or green wood. Woodworking machines and memory devices for use in woodworking machines having safety systems designed to detect a dangerous condition between a human and a dangerous portion of the woodworking machine and to trigger some action to mitigate the dangerous condition are also disclosed.

Claims

1. A memory device for use in a woodworking machine having a safety system designed to detect a dangerous condition between a human and a dangerous portion of the woodworking machine and to trigger some action to mitigate the dangerous condition, the memory device comprising:

a module configured to be positioned within a woodworking machine and, further configured to be removable from the woodworking machine, where the module includes a housing;

permanent memory within the housing; and

a system to store data to the permanent memory, where the data indicates the cause of the trigger of the action to mitigate the dangerous condition.

2. The memory device of claim 1, where the permanent memory is flash memory.

3. The memory device of claim 2, where the flash memory is part of a digital signal processor.

4. The memory device of claim 1, where the woodworking machine is a table saw.

5. The memory device of claim 1, where the dangerous portion is a blade.

6. A memory device for use in a woodworking machine having a safety system designed to detect a dangerous condition between a human and a dangerous portion of the woodworking machine by imparting an electrical signal to the dangerous portion and monitoring that signal for predetermined changes indicative of the dangerous condition, and where the safety system is further designed to trigger some action to mitigate the dangerous condition upon detection of the predetermined changes in the electrical signal indicative of the dangerous condition, the memory device comprising:

a module configured to be positioned within a woodworking machine and further configured to be removable from the woodworking machine, where the module includes a housing;

permanent memory within the housing; and

a system to store data to the permanent memory, where the data includes at least the predetermined changes in the electrical signal that caused the safety system to trigger the action to mitigate the dangerous condition.

7. A woodworking machine comprising:

a cutting tool for cutting workpieces;

at least one motor configured to drive the cutting tool;

a detection system configured to detect a dangerous condition associated with the cutting tool by imparting an electrical signal on a portion of the woodworking machine and monitoring the electrical signal for predetermined changes indicative of the dangerous condition;

a reaction system triggerable to perform some action to mitigate the dangerous condition when the detection system detects the predetermined changes in the electrical signal indicative of the dangerous condition;

permanent nonvolatile memory; and

a system to store data to the permanent nonvolatile memory, where the data includes the predetermined changes in the electrical signal that cause the triggering of the reaction system.

8. The woodworking machine of claim 7, where the dangerous condition is contact between a human and the cutting tool.

9. The woodworking machine of claim 7, where the dangerous condition is proximity between a human and the cutting tool.