Electromagnetic actuator for power tool

Patent metadata

Field	Value
Publication number	US-12365076-B2
Application number	US-202117345848-A
Country	US
Kind code	B2
Filing date	Jun 11, 2021
Priority date	Jun 24, 2011
Publication date	Jul 22, 2025
Grant date	Jul 22, 2025

Abstract

An actuator assembly for a power tool includes an actuator with a permanent magnet. The actuator is moveable between a first position for a first mode of operation, and a second position for a second mode of operation. A first positioning member is adjacent the first position composed of a ferromagnetic material to attract the permanent magnet. A second positioning member is adjacent the second position and composed of a ferromagnetic material to attract the permanent magnet. An electromagnet may be energized to move the actuator between the first position and the second position. When the electromagnet is not energized and the actuator is in the first position, the actuator is retained in the first position. When the electromagnet is not energized and the actuator is in the second position, the actuator is retained in the second position. When the electromagnet is energized, the actuator moves between the first and second positions.

First claim

What is claimed is:

1. An actuator assembly for a power tool, comprising:
a positioning member remaining axially stationary along an axis;
an actuator moveable along the axis between a first position closer to the positioning member that corresponds to a first mode of operation of the power tool, and a second position further from the positioning member that corresponds to a second mode of operation of the power tool;
a first permanent magnet assembly fixed to the actuator and a second permanent magnet assembly fixed to the positioning member, wherein the first permanent magnet assembly and the second permanent magnet assembly are configured to attract each other by an attractive force when the actuator is in the first position and to repel each other by a repulsive force when the actuator is in the second position; and
an electromagnet axially stationary relative to the positioning member,
wherein when the actuator is in the first position, the electromagnet can be momentarily energized to generate a magnetic force sufficient to overcome the attractive force and move the actuator to the second position, where the actuator will be maintained in the second position after the electromagnet is deenergized due to the repulsive force, and
when the actuator is in the second position, the electromagnet can be momentarily energized to generate a magnetic force sufficient to overcome the repulsive force and move the actuator to the first position, where the actuator will be maintained in the first position after the electromagnet is deenergized due to the attractive force.

2. The actuator assembly of claim 1 , wherein the first permanent magnet assembly includes a first plurality of permanent magnets and the second permanent magnet assembly includes a second plurality of permanent magnets, with a first portion of the first plurality of permanent magnets and a first portion of the second plurality of permanent magnets arranged to exert the attractive force and a second portion of the first plurality of permanent magnets and a second portion of the second plurality of permanent magnets are arranged to exert the repulsive force.

3. The actuator assembly of claim 2 , wherein the first plurality of permanent magnets and the second plurality of permanent magnets each comprise an array of correlated magnets.

4. The actuator assembly of claim 2 , wherein the first plurality of permanent magnets comprises a first magnet and a second magnet arranged so that they have the same polarity as each other along the axis, and the second plurality of magnets comprises a third magnet and a fourth magnet arranged so that they have the opposite polarity from each other along the axis.

5. The actuator assembly of claim 1 , wherein the electromagnet can be momentarily energized by current flowing in a first direction to move the actuator from the first position to the second position, and can be momentarily energized by current flowing in a second opposite direction to move the actuator from the second position to the first position.

6. The actuator assembly of claim 1 , further comprising a control circuit configured to control energization of the electromagnet in response to an input condition, the input condition comprising at least one of a user selection of a desired power tool operating condition or a sensed power tool operating condition.

7. The actuator assembly of claim 1 , wherein the actuator, the positioning member, and the electromagnet comprise a portion of a clutch of the power tool, the clutch having an input member coupled to a transmission of the power tool, an output member coupled to an output shaft of the power tool, and a coupling device movable between a driving position in which torque is transmitted from the input member to the output member and a clutching position in which torque transmission from the input member to the output member is interrupted, and wherein when the actuator is in the first position, the actuator retains the coupling member in the driving position, and when then actuator is in the second position, the actuator allows the coupling member to move to the clutching position.

8. The actuator assembly of claim 7 , wherein the input member comprises an input sleeve defining a radial bore, the output member comprises an output cylinder received in the input sleeve defining a groove, the coupling member comprises a drive ball received in the bore, and the actuator comprises a actuation sleeve received over the input sleeve, wherein when the actuation sleeve is in the first position, the ball is retained in the groove to transmit torque from the input sleeve to the output cylinder, and when the actuation sleeve is in the second position, the ball is permitted to escape the groove to interrupt torque transmission from the input sleeve to the output cylinder.

9. The actuator assembly of claim 7 , wherein the input member comprises a ring gear of the transmission having a recess, the output member comprises a portion of the output shaft, the actuator comprises a sleeve, and the coupling member comprises a leg extending from the sleeve, wherein when the sleeve is in the first position, the leg engages the recess to inhibit rotation of the ring gear, which enables torque transmission to the output member, and when the sleeve is in the second position, the leg does not engage the recess to allow rotation of the ring gear, which interrupts torque transmission to the output member.

10. The actuator assembly of claim 1 , wherein the actuator, the positioning member, and the electromagnet comprise a portion of a tool holder of the power tool, the tool holder coupled to the output shaft for releasably retaining a power tool accessory, wherein when the actuator is in the first position, the accessory is retained by the tool holder, and when the actuator is in the second position the accessory is releasable from the tool holder.

11. The actuator assembly of claim 10 , wherein the tool holder comprises a socket drive having a retractable retention pin and a linkage coupled to the retention pin for selectively retracting the retention pin, and wherein the actuator comprises a ring configured to move the linkage and the retention pin between a retention position and a release position when the actuator is in the first position and the second position, respectively.

12. The actuator assembly of claim 1 , further comprising a stop to prevent contact between the actuator and the positioning member when the actuator is in the first position.

13. An actuator assembly for a power tool, comprising:
an actuator moveable between a first position in which an output member of the power tool is coupled to an input member of the power tool so that movement of the input member causes movement of the output member and a second position in which the output member is decoupled from the input member so that movement of the input member does not cause movement of the output member;
a first permanent magnet assembly fixed to the actuator and a second permanent magnet assembly fixed to one of the input member and the output member, wherein the first permanent magnet assembly and the second permanent magnet assembly are configured to attract each other by an attractive force when the actuator is in the first position and to repel each other by a repulsive force when the actuator is in the second position; and
an electromagnet disposed adjacent the actuator,
wherein when the actuator is in the first position, the electromagnet can be momentarily energized to generate a magnetic force sufficient to overcome the attractive force and move the actuator to the second position, where the actuator will be ma

Assignees

• Black & Decker Inc

Inventors

• Puzio Daniel
• Gehret Robert S
• Cox John D
• Opsitos Jr Robert J
• Kusmierski Robert G
• Schell Craig A
• Haupt Michael T
• Kelleher Joseph P

Classifications

• H01H36/0073

  actuated by relative movement between two magnets · CPC title

• B25B23/147

  specially adapted for electrically operated wrenches or screwdrivers · CPC title

• B25B23/0035

  Connection means between socket or screwdriver bit and tool · CPC title

• B25B23/1475

  for impact wrenches or screwdrivers · CPC title

• B25B21/02

  with means for imparting impact to screwdriver blade or nut socket · CPC title