Electric pulse tool

Patent metadata

Field	Value
Publication number	US-11548123-B2
Application number	US-201816606709-A
Country	US
Kind code	B2
Filing date	Apr 5, 2018
Priority date	Apr 19, 2017
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

An electric pulse tool is configured to deliver torque in pulses on an output shaft thereof and includes an electric motor to drive the output shaft. The electric pulse tool is configured to, for each period, provide a current pulse to the electric motor during a current-on time interval, pause a current feed to the electric motor after the current-on time interval until an end of a torque pulse, determine a width of the torque pulse, and continue pausing the current feed to the electric motor during a pause interval from the end of the torque pulse. The pause interval is determined based on the width of the torque pulse such that a wider torque pulse results in a wider pause interval and a narrower torque pulse results in a shorter pause interval.

First claim

The invention claimed is:

1. An electric pulse tool configured to deliver torque in pulses on an output shaft thereof, the electric pulse tool comprising:
an electric motor configured to drive the output shaft; and
a processor and a memory storing instructions that are executable by the processor to control the electric pulse tool to perform operations including, for each of a plurality of periods:
providing a current pulse to the electric motor during a current-on time interval;
pausing a current feed to the electric motor after the current-on time interval until an end of a torque pulse generated due to the current pulse;
determining a width of the torque pulse;
determining a width of a pause interval, which is an interval from the end of the torque pulse to a beginning of a next current pulse, such that a wider torque pulse results in a wider pause interval and a narrower torque pulse results in a shorter pause interval; and
continuing pausing the current feed to the electric motor during the pause interval.

2. The electric pulse tool according to claim 1 , wherein the width of the torque pulse is determined based on an interval from a first point in time when the electric pulse tool starts to transfer energy on the output shaft to a second point in time when the electric pulse tool stops transferring energy on the output shaft.

3. The electric pulse tool according to claim 2 , further comprising:
a torque sensor,
wherein the transfer of energy on the output shaft is determined based on a determined torque on the output shaft.

4. The electric pulse tool according to claim 2 , further comprising:
a position sensor,
wherein the transfer of energy on the output shaft is determined based on a determined position change of the output shaft.

5. The electric pulse tool according to claim 3 , wherein the transfer of energy on the output shaft is determined to have stopped when the determined torque reaches essentially zero.

6. The electric pulse tool according to claim 1 , wherein the pause interval is a predetermined factor of the width of the torque pulse minus the current-on time interval.

7. The electric pulse tool according to claim 1 , wherein the processor executing the instructions controls the electric pulse tool to repeat said periods until a parameter value associated with tightening of a screw joint has been reached.

8. The electric pulse tool according to claim 7 , wherein the parameter value associated with the tightening of the screw joint is torque.

9. The electric pulse tool according to claim 7 , wherein the parameter value associated with the tightening of the screw joint is angle.

10. The electric pulse tool according to claim 1 , wherein each of the periods is a period from a beginning of the current pulse to the beginning of the next current pulse.

11. A method for controlling the electric pulse tool according to claim 1 , the method comprising, for each of the plurality of periods:
providing the current pulse to the electric motor during the current-on time interval;
pausing the current feed to the electric motor after the current-on time interval until the end of the torque pulse generated due to the current pulse;
determining the width of the torque pulse;
determining the width of the pause interval, which is the interval from the end of the torque pulse to the beginning of the next current pulse, such that a wider torque pulse results in a wider pause interval and a narrower torque pulse results in a shorter pause interval; and
continuing pausing the current feed to the electric motor during the pause interval.

12. The method according to claim 11 , wherein the width of the torque pulse is determined based on an interval from a first point in time when the electric pulse tool starts to transfer energy on the output shaft to a second point in time when the electric pulse tool stops transferring energy on the output shaft.

13. The method according to claim 12 , further comprising determining if energy is transferred on the output shaft based on a determined torque on the output shaft.

14. The method according to claim 12 , further comprising determining if energy is transferred on the output shaft based on a determined position change of the output shaft.

15. The method according to claim 13 , wherein the transfer of energy on the output shaft is determined to have stopped when the determined torque reaches essentially zero.

16. The method according to claim 11 , wherein the pause interval is a predetermined factor of the width of the torque pulse minus the current-on time interval.

17. A non-transitory computer-readable storage medium, having stored thereon a program executable by a processor of an electric pulse tool, the program being executable by the processor to control the electric pulse tool to perform the method according to claim 11 .

Assignees

• Atlas Copco Ind Technique Ab

Inventors

• Klotblixt Adam

Classifications

• B25B23/147 Primary

  specially adapted for electrically operated wrenches or screwdrivers · CPC title

• H02P27/085

  wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency · CPC title

• B25B21/00 Primary

  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 title

• H02K7/145

  Hand-held machine tool · CPC title

• H02P8/10

  Shaping pulses for starting; Boosting current during starting · CPC title