Power tool having multiple operating modes

Abstract

A handheld power tool is configured to receive an input indicative of a clutch setting for an electronic clutch from the tool operator, where the clutch setting is selectable from a drill mode, an automated drive mode and one or more user-defined drive modes. Each of the user-defined drive modes specifies a different value of torque at which to interrupt transmission of torque to the output spindle. In an automated drive mode, the controller interrupt torque to the output spindle in an automated manner when a fastener being driven reaches a desired stopping position. In a selected one of the user-defined drive modes, the controller sets a value of a maximum current threshold in accordance with the selected one of the user-defined drive modes and interrupts torque to the output spindle when current measures exceeding the maximum current threshold.

What is claimed is: 
     
         1 . A method of controlling operation of a power tool having an electric motor drivably connected to an output spindle to impart rotary motion thereto, comprising:
 receiving, by a controller residing in the power tool, an input indicative of a clutch setting for an electronic clutch, the clutch setting being selectable from a drill mode and a drive mode;   monitoring, by the controller, torque applied to the output spindle when the clutch setting is in a drive mode by
 sampling periodically current delivered to the electric motor; 
 storing a sequence of current measures most recently sampled, the sequence of current measures being stored in a memory of the power tool; and 
 determining a slope for the sequence of current measures by way of linear regression; 
   interrupting, by the controller, transmission of torque to the output spindle based in part on the slope of the sequence of current measures and when the clutch setting is in a drive mode; and   disregarding, by the controller, torque applied to the output spindle when the clutch setting is in drill mode.   
     
     
         2 . The method of  claim 1  further comprises
 detecting, by the controller, an occurrence of a trigger switch being released and subsequently depressed by the tool operator, where the trigger switch controls quantity of electric power delivered to the electric motor and the occurrence of the trigger switch being released and subsequently depressed by the tool operator occurs within a time limit of interrupting transmission of torque; and 
 energizing, by the controller, the electric motor for a period of time after generating haptic feedback and in response to detecting the occurrence of the trigger switch being released and subsequently depressed by the tool operator. 
 
     
     
         3 . The method of  claim 1  further comprises
 comparing, by the controller, the slope to a minimum slope threshold; 
 incrementing, by the controller, a slope counter by one when the slope exceeds the minimum slope threshold; 
 evaluating, by the controller, the slope counter in relation to a setting criteria, where the setting criteria is indicative of a desired stopping position for a fastener being driven by the power tool; and 
 interrupting, by the controller, transmission of torque to the output spindle when the slope counter meets the setting criteria. 
 
     
     
         4 . The method of  claim 3  further comprises
 storing, by the controller, a sequence of values for the slope counter; and 
 evaluating, by the controller, the sequence of values for the slope counter in relation to the setting criteria. 
 
     
     
         5 . The method of  claim 4  further comprises interrupting transmission of torque when values in the sequence of values for the slope counter are increasing from an oldest value to a most recent value. 
     
     
         6 . The method of  claim 4  further comprises interrupting transmission of torque when values in the sequence of values for the slope counter increase from an oldest value to an intermediate value and decrease from the intermediate value to a most recent value. 
     
     
         7 . The method of  claim 1  further comprises providing a visual indicator for the clutch setting during the operation of the tool. 
     
     
         8 . The method of  claim 1  wherein receiving an input further comprises receiving a signal from one or two buttons provided on a housing of the power tool, where one of the two buttons is associated with the drill mode and other of the two buttons is associated with the drive mode. 
     
     
         9 . The method of  claim 8  further comprises illuminating an icon integrated into one of the two buttons actuated by the tool operator, where the icon is indicative of the operating mode associated with the actuated button. 
     
     
         10 . The method of  claim 1  further comprising
 determining, by the controller, a magnitude of current being delivered to the electric motor immediately prior to interrupting transmission of torque; 
 storing, by the controller, the magnitude of current in a storage device in response to an input from the tool operator; 
 interrupting transmission of torque to the output spindle during a subsequent operation of the tool when the amount of current being delivered to the electric motor is equal to or exceeds the stored magnitude of current. 
 
     
     
         11 . A portable, hand held power tool, comprising:
 a housing;   an electric motor drivable connected to an output spindle to impart rotary motion thereto;   a current sensor configured to sample current being delivered to the electric motor;   an input component operable by the tool operator to set a clutch setting for tool, the clutch setting being selectable from a drill mode, an automated drive mode and one or more user-defined drive modes, where each of the user-defined drive modes specifies a different value of torque at which to interrupt transmission of torque to the output spindle; and   a controller configured to receive the clutch setting from the input component and current measures from the current sensor, wherein the controller operates, when the clutch setting is an automated drive mode, to interrupt torque to the output spindle monitor rate of change of the current measures and interrupt torque to the output spindle in response to the rate of change of current measures exceeding a rate change threshold, the controller further operates, when the clutch setting is in a selected one of the user-defined drive modes, to set a value of a maximum current threshold in accordance with the selected one of the user-defined drive modes and interrupt torque to the output spindle in response to the current measures exceeding the maximum current threshold.   
     
     
         12 . The power tool of  claim 11  wherein the controller, when the clutch setting is an automated drive mode, operates to receive current measure from the current sensor, stores a sequence of current measures most recently sampled in a memory of the power tool, and determine a slope for the sequence of current measures by way of linear regression and operates to interrupt transmission of torque based in part on the slope of the sequence of current measures. 
     
     
         13 . The power tool of claim of  claim 12  wherein the controller further operates to compare the slope to a minimum slope threshold; adjust a slope counter in accordance with the comparison of the slope with the minimum slope threshold, evaluate the slope counter in relation to a setting criteria, and interrupt transmission of torque to the output spindle when the slope counter meets the setting criteria, where the setting criteria is indicative of a desired stopping position for a fastener being driven by the power tool. 
     
     
         14 . The power tool of  claim 10  wherein the controller, when the clutch setting is a drill mode, ignores torque applied to the output spindle. 
     
     
         15 . The power tool of  claim 10  wherein the controller provides haptic feedback to the tool operator concurrently with interrupting transmission of torque to the output spindle. 
     
     
         16 . The power tool of  claim 10  wherein the input component is further defined as two pushbuttons integrated into the housing, such that actuation of one pushbutton sets the clutch setting to a drill mode and actuation of the other pushbutton sets the clutch setting to a drive mode. 
     
     
         17 . The power tool of  claim 16  wherein one of the two pushbuttons actuated by the tool operator is illuminated during operation of the tool. 
     
     
         18 . The power tool of  claim 10  wherein the input component is further defined as a rotary potentiometer switch assembly including:
 an assembly platform rotatably mounted to the body; 
 a rotary device rotatably mounted to the assembly platform such that manual axial rotation of the rotary device acts to create a clutch setting; and 
 opposed first and second directional switches mounted to the assembly platform, wherein when one of the first or second directional switches contacts the body during a manual rotation of the assembly platform, either a forward or a reverse operating direction of rotation command for the output spindle is created. 
 
     
     
         19 . The power tool of  claim 10  further comprising a display port located on the housing including multiple bi-color light emitting diodes (LEDs) each operating to display three colors, including two primary colors and a third color which is a mix of the two primary colors, each LED color providing visual indication of multiple different operating modes of the power tool. 
     
     
         20 . The power tool of  claim 10  further comprising a display port located on the housing, wherein a numeric value for the selected one of the user-defined drive modes is presented on the display port.