# US 2019/0168362 A1 · Electric pulse tool > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0168362 A1 - Document ID: US20190168362A1 - Status: Published application - Kind: A1 - Application number: 16/313,691 - Filed: 2017-06-19 - Published: 2019-06-06 - Earliest claimed: 2016-06-30 - Assignees: Atlas Copco Industrial Technique AB - Applicants: Atlas Copco Industrial Technique AB - Inventors: Adam KLOTBLIXT - Web page: https://patentgrep.com/patent/US20190168362A1 ## CPC - B25B 21/02: with means for imparting impact to screwdriver blade or nut socket - 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) - B25B 23/1405: {for impact wrenches or screwdrivers} - B25B 23/1425: {by electrical means} - B25B 23/147: specially adapted for electrically operated wrenches or screwdrivers - H02P 7/03: for controlling the direction of rotation of DC motors - B25B: TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING, OR HOLDING - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS ## Abstract An electric power tool includes an electrical motor adapted to drive a rotating shaft. The electric motor is adapted to be fed with a pulsed current where the pulsed current includes a main current pulse (A) in a first direction driving the rotating shaft in a first direction and adapted to provide a current (C) in an opposite direction following the main current pulse to retract the electrical power tool. The pulsed current prior to the current (C) in the opposite direction includes a first pre-pulse current pulse (B) in the same direction as the current in the opposite direction and of a magnitude lower than the current (C). The pulsed current prior to the main pulse includes a second pre-pulse current pulse (D) which is in the same direction as the main current pulse and of a magnitude lower than the main current pulse. ## Claims ### Claim at position 1 1-28. (canceled) ### Claim 29 An electric power tool comprising an electrical motor adapted to drive a rotating shaft of the electric power tool, the electric motor adapted to be fed with a pulsed current where the pulsed current comprises a main current pulse (A) in a first direction driving the rotating shaft in a first direction and adapted to provide a current (C) in an opposite direction to the first direction following the main current pulse to retract the electrical power tool, wherein the pulsed current prior to the current (C) in the opposite direction comprises a first pre-pulse current pulse (B) in the same direction as the current in the opposite direction and of a magnitude lower than the current in the opposite direction and wherein the pulsed current prior to the main pulse comprises a second pre-pulse current pulse (D) wherein the current pulse of the second pre-pulse is in the same direction as the main current pulse and of a magnitude lower than the main current pulse. ### Claim 30 (depends on 29) The electric power tool according to claim 29, further comprising a torque sensor for sensing an actual torque provided during a tightening operation performed by the electric power tool. ### Claim 31 (depends on 29) The electric power tool according to claim 29, wherein the electrical motor is connected to the rotating shaft via a gear arrangement. ### Claim 32 A method of controlling current supplied to a motor of an electric power tool, the electric power tool comprising a rotating shaft driven by the motor, the control method comprising providing a pulsed current comprising a main current pulse (A) in a first direction driving the rotating shaft in a first direction to add torque to a joint and a current (C) in an opposite direction to the first direction following the main current pulse to retract the electrical power tool, the method further comprising providing a first pre-pulse current pulse (B) prior to the current pulse in the opposite direction wherein the current pulse of the first pre-pulse is in the same direction as the current pulse in the opposite direction and of a magnitude lower than the current pulse in the opposite direction and providing a second pre-pulse current pulse (D) prior to the main pulse wherein the current pulse of the second pre-pulse is in the same direction as the main current pulse and of a magnitude lower than the main current pulse. ### Claim 33 (depends on 32) The method according to claim 32, wherein a magnitude of the current pulse in the opposite direction is selected to not loosen the joint. ### Claim 34 (depends on 33) The method according to claim 33, wherein the magnitude of the current pulse in the opposite direction is correlated to a magnitude of the main current pulse. ### Claim 35 (depends on 34) The method according to claim 34, wherein the magnitude of the current pulse in the opposite direction is linearly correlated to the magnitude of the main current pulse. ### Claim 36 (depends on 32) The method according to claim 32, wherein the magnitude of the current pulse in the opposite direction is 5-50% of a magnitude of the main current pulse. ### Claim 37 (depends on 32) The method according to claim 32, wherein the current pulse in the opposite direction comprises a ramped leading edge. ### Claim 38 (depends on 37) The method according to claim 37, wherein the ramped leading edge is linearly ramped. ### Claim 39 (depends on 35) The method according to claim 35, wherein the first pre-pulse is applied until a pre-set threshold value of a measured applied torque to the joint is reached. ### Claim 40 (depends on 35) The method according to claim 35, wherein the second pre-pulse is applied until a pre-set threshold value of a measured applied torque to the joint is reached. ### Claim 41 A method of controlling current supplied to a motor of an electric power tool, the electric power tool comprising a rotating shaft driven by the motor, the control method comprising providing a pulsed current comprising a main current pulse (A) in a first direction driving the rotating shaft in a first direction to add torque to a joint and providing a current pulse (D) prior to the main pulse wherein the current pulse is in the same direction as the main current pulse and of a magnitude lower than the main current pulse to remove forward backlash. ### Claim 42 (depends on 41) The method according to claim 41, wherein a magnitude of the current pulse (D) is 10-20% or less than a magnitude of the main current pulse (A). ### Claim 43 (depends on 41) The method according to claim 41, wherein the current pulse is provided until a measured torque in the joint is above a threshold value. ### Claim 44 (depends on 32) A power tool adapted to perform the method according to claim 32. ### Claim 45 (depends on 41) A power tool adapted to perform the method according to claim 41. ### Claim 46 (depends on 32) A control unit adapted to perform the method according to claim 32. ### Claim 47 (depends on 41) A control unit adapted to perform the method according to claim 41. ### Claim 48 (depends on 46) The control unit according to claim 46, wherein the control unit is external to a power tool controlled by the control unit. ### Claim 49 (depends on 47) The control unit according to claim 47, wherein the control unit is external to a power tool controlled by the control unit.