Router with improved safety system

Abstract

A router is described for cutting workpieces with router bits. The router includes a safety system configured to detect one or more dangerous conditions between a person and a router bit. The safety system includes a reaction subsystem configured to perform one or more predetermined actions in the event a dangerous condition is detected. In one embodiment, the safety system is configured to detect accidental contact between a person and the router bit, and then at least partially retract the router bit the person.

We claim:  
     
         1 . A router for cutting workpieces with one or more router bits, the router comprising: 
 an operative structure configured to support a router bit in a nominal operating position to cut workpieces;    a motor assembly coupled to rotate at least a portion of the operative structure; and    a safety system including a detection subsystem configured to detect one or more dangerous conditions between a person and a router bit supported by the operative structure, and a reaction subsystem configured to retract the router bit at least partially away from the nominal operating position if one or more dangerous conditions are detected by the detection subsystem.    
     
     
         2 . The router of  claim 1 , where the reaction subsystem is configured to engage and stop the rotation of at least a portion of the operative structure if one or more dangerous conditions are detected by the detection subsystem.  
     
     
         3 . The router of  claim 1 , where the reaction subsystem is configured to retract the router bit at least partially away from the nominal operating position within approximately 10 milliseconds after one or more dangerous conditions are detected by the detection subsystem.  
     
     
         4 . The router of  claim 1 , where the portion of the operative structure has rotational energy when rotating, and where the reaction subsystem is configured to utilize at least a portion of the rotational energy of the operative structure to retract the router bit.  
     
     
         5 . The router of  claim 1 , where the operative structure includes a rotatable shaft coupled to the motor assembly, a chuck configured to support a router bit, and a releasable coupling configured to rotationally couple the chuck to the shaft, and where the releasable coupling is configured to rotationally uncouple the chuck from the shaft when the reaction subsystem retracts the router bit at least partially away from the nominal operating position.  
     
     
         6 . The router of  claim 1 , where the operative structure includes a retractable spindle assembly configured to support a router bit in the nominal operating position, and where the retractable spindle assembly is selectively movable in a direction away from the nominal operating position, and where the reaction subsystem is configured to apply a retracting force on the retractable spindle assembly in a direction away from the nominal operating position if one or more dangerous conditions are detected by the detection subsystem.  
     
     
         7 . The router of  claim 6 , where the motor assembly is coupled to rotate the retractable spindle assembly during operation, where the retractable spindle assembly has rotational energy when rotating, and where the reaction subsystem is configured to convert at least a portion of the rotational energy of the retractable spindle assembly into the retracting force on the retractable spindle assembly if one or more dangerous conditions are detected by the detection subsystem.  
     
     
         8 . The router of  claim 7 , where the reaction subsystem includes a spindle engagement member configured to selectively engage a portion of the retractable spindle assembly and urge the retractable spindle assembly in a direction away from the nominal operating position.  
     
     
         9 . The router of  claim 8 , further comprising a housing configured to at least partially enclose the motor assembly and the operative structure, and a disposable cartridge assembly removably mounted to the housing, and where the spindle engagement member is mounted in the cartridge assembly.  
     
     
         10 . The router of  claim 1 , further comprising a housing configured to at least partially enclose the motor assembly and the operative structure, and a disposable cartridge assembly removably mounted to the housing, and where at least a portion of the reaction subsystem is mounted in the disposable cartridge assembly.  
     
     
         11 . For use with a router adapted to rotationally drive a router bit, a method for minimizing injury from a router bit coupled to the router, the method comprising: 
 detecting accidental contact between a person and the router bit; and    at least partially retracting the router bit away from the person in the event accidental contact between the person and the router bit is detected.    
     
     
         12 . The method of  claim 11 , where the step of retracting includes at least partially retracting the router bit away from the person within 10 milliseconds after the accidental contact between a person and the router bit is detected.  
     
     
         13 . The method of claim B, further comprising the step of stopping the rotation of the router bit in the event accidental contact between the person and the router bit is detected.  
     
     
         14 . The method of  claim 11 , where the step of detecting includes the steps of: 
 applying an electrical to the router bit, and    monitoring the electrical signal on the router bit changes indicative of accidental contact between a person and the router bit.    
     
     
         15 . The method of  claim 11 , where the router includes rotatable operative structure configured to support a router bit, where the operative structure has angular momentum when rotating, and where the step of retracting includes converting at least a portion of the angular momentum of the operative structure into a retraction force on the operative structure in a direction away from the person.  
     
     
         16 . A router comprising: 
 means for rotationally driving a router bit;    means for detecting accidental contact between a person and the router bit; and    means for at least partially retracting the router bit away from the person in the event accidental contact between the person and the router bit is detected.    
     
     
         17 . The router of  claim 16 , further comprising means for stopping the rotation of the router bit in the event accidental contact between the person and the router bit is detected.  
     
     
         18 . The router of  claim 16 , where the means for retracting includes means for retracting the router bit away from the person within 10 milliseconds after accidental contact between the person and the router bit is detected.  
     
     
         19 . The router of  claim 16 , further comprising biasing means for maintaining the router bit in a nominal operating position until accidental contact between the person and the router bit is detected.  
     
     
         20 . The router of  claim 19 , where the biasing means include means for releasably maintaining the router bit in a fully retracted position after contact between the person and the router bit is detected.