Trigger profile for a power tool

• US 8,403,072 B2
• Filed: 06/22/2012
• Issued: 03/26/2013
• Est. Priority Date: 01/07/2010
• Status: Active Grant

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Eshleman, Scott, Kelleher, Joseph P.
• Primary Examiner(s): Smith, Scott A.
• Application Number:
  US13/530,452
• Publication Number:
  US 20120273242A1
• Time in Patent Office: 277 Days
• Field of Search: 173/1, 173/2, 173/4, 173/176, 173/178, 173/181, 173/183, 173/216, 173/217
• US Class Current: 173/1
• CPC Class Codes: B23B 2220/08 Deburring
• CPC Class Codes: B25B 21/00 Portable power-driven screw or nut setting or loosening tools; details or components, e.g. casings, bodies, of portable power-driven tools not particularly related to the operation performed B25F5/00; for mounting or dismounting wheels B60B29/006; Attachments for drilling apparatus serving the same purpose machines B23P19/06
• CPC Class Codes: B25B 21/008 with automatic change-over from high speed-low torque mode to low speed-high torque mode
• CPC Class Codes: B25B 23/00 Details of, or accessories for, spanners, wrenches, screwdrivers bolt tensioners B25B29/02
• CPC Class Codes: B25B 23/0064 Means for adjusting screwing depth
• CPC Class Codes: B25B 23/14 Arrangement of torque limiters or torque indicators in wrenches or screwdrivers couplings for transmitting rotation or clutches F16D; devices for measuring torque per se G01L
• CPC Class Codes: B25B 23/147 specially adapted for electrically operated wrenches or screwdrivers
• CPC Class Codes: B25D 2250/221 Sensors
• CPC Class Codes: B25F 5/00 Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
• CPC Class Codes: B25F 5/001 Gearings, speed selectors, clutches or the like specially adapted for rotary tools
• CPC Class Codes: E21B 15/04 specially adapted for directional drilling, e.g. slant hole rigs
• CPC Class Codes: H01H 9/06 Casing of switch constituted by a handle serving a purpose other than the actuation of the switch, e.g. by the handle of a vacuum cleaner

Abstract

An improved method is provided for operating a power tool. The method includes receiving an input control variable from an input unit; determining a derivative of the input control variable; selecting one of a plurality of control profiles based on the control input variable and the derivative, each control profile correlating the control input variable of the input unit to a rotational speed at which to drive the output shaft; and driving the output shaft at a rotational speed in accordance with the selected control profile.

Claims

1. A method for operating a power tool having an output shaft, comprising:

receiving an input control variable from an input unit;

determining a derivative of the input control variable;

selecting one of a plurality of control profiles based on the control input variable and the derivative, each control profile correlating the control input variable of the input unit to a rotational speed at which to drive the output shaft; and

driving the output shaft at a rotational speed in accordance with the selected control profile.

2. The method of claim 1 further comprising:

selecting a first control profile from the plurality of control profiles when the derivative of the control input variable is above a first threshold and selecting a second control profile from the plurality of control profiles when the derivative of the control input variable is below the first threshold, where the first control profile differs from the second control profile.

3. The method of claim 2, wherein the first control profile designates maximum rotational speed of the output shaft for a predetermined range of the corresponding control input variable and the second control profile designates a linear control relationship between the rotational speed of the output shaft and the corresponding control input variable.

4. The method of claim 3, further comprising selecting a third control profile from the plurality of control profiles when the variable of the control input variable is below a second threshold below the first threshold, wherein the third control profile designates a control curve comprising a first linear curve corresponding to a first range of the control input variables and a second linear curve steeper than the first linear curve and corresponding to a second range of control input variables.

5. The method of claim 1, wherein the input unit comprises a trigger switch and the control input variable comprises one of a displacement, velocity, or acceleration of the trigger switch.

6. The method of claim 1, wherein control input variable comprises a displacement of the input unit and the derivative of the control input variable comprises a speed at which the input unit is actuated.

7. The method of claim 1, wherein the input unit comprises a rotational motion sensor disposed in the power tool and configured to measure rotational motion of the power tool about an axis aligned substantially parallel with a longitudinal axis of the output shaft.

8. The method of claim 7, wherein the control input variable comprises an angular displacement of the tool about the axis and the derivative comprises an angular velocity of the tool about the axis.

9. The method of claim 8, further comprising determining the angular displacement of the tool about the axis in relation to a reference position and driving the output shaft at a rotational speed that correlates to the angular displacement of the tool from the reference position based on the selected control profile.

10. The method of claim 9, further comprising resetting the reference position to zero in response to an input command from an operator of the tool.

11. A power tool comprising:

a housing;

an output member configured to rotate about a longitudinal axis;

a motor contained in the housing and driveably connected to the output member to impart rotary motion thereto;

an input unit configured to output an input control variable in response to a user action; and

a controller in the housing configured to calculate a derivative of the input control variable, select one of a plurality of control profiles based on the control input variable and the derivative, and drive the output shaft via the motor at a rotational speed in accordance with the selected control profile, wherein each control profile correlating the control input variable of the input unit to a rotational speed at which to drive the output shaft.

12. The power tool of claim 11, wherein the controller is configured to select a first control profile from the plurality of control profiles when the derivative of the control input variable is above a first threshold and select a second control profile from the plurality of control profiles when the derivative of the control input variable is below the first threshold, where the first control profile differs from the second control profile.

13. The power tool of claim 12, wherein the first control profile designates maximum rotational speed of the output shaft for a predetermined range of the corresponding control input variable and the second control profile designates a linear control relationship between the rotational speed of the output shaft and the corresponding control input variable.

14. The power tool of claim 13, wherein the controller is further configured to select a third control profile from the plurality of control profiles when the variable of the control input variable is below a second threshold below the first threshold, wherein the third control profile designates a control curve comprising a first linear curve corresponding to a first range of the control input variables and a second linear curve steeper than the first linear curve and corresponding to a second range of control input variables.

15. The power tool of claim 11, wherein the input unit comprises a trigger switch and the control input variable comprises one of a displacement, velocity, or acceleration of the trigger switch.

16. The power tool of claim 11, wherein control input variable comprises a displacement of the input unit and the derivative of the control input variable comprises a speed at which the input unit is actuated.

17. The power tool of claim 11, wherein the input unit comprises a rotational motion sensor disposed in the power tool and configured to measure rotational motion of the power tool about an axis aligned substantially parallel with a longitudinal axis of the output shaft.

18. The power tool of claim 17, wherein the control input variable comprises an angular displacement of the tool about the axis and the derivative comprises an angular velocity of the tool about the axis.

19. The power tool of claim 18, wherein the controller is configured to determine the angular displacement of the tool about the axis in relation to a reference position and driving the output shaft at a rotational speed that correlates to the angular displacement of the tool from the reference position based on the selected control profile.

20. The power tool of claim 19, wherein the controller is configured to reset the reference position to zero in response to an input command from an operator of the tool.