Detection systems for power equipment
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.
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.