Contactless trigger with rotational magnetic sensor for a power tool

Patent metadata

Field	Value
Publication number	US-12115644-B2
Application number	US-202318490295-A
Country	US
Kind code	B2
Filing date	Oct 19, 2023
Priority date	May 13, 2019
Publication date	Oct 15, 2024
Grant date	Oct 15, 2024

Abstract

A trigger assembly for a power tool includes a housing, a moveable plunger extending from a surface of the housing, the movable plunger includes a first end disposed externally from the housing and a second end disposed internally within the housing. The trigger assembly further includes a trigger shoe coupled to the first end of the moveable plunger, and an arm including a first side that is moveably connected to the second end of the moveably plunger and a second side that is coupled to a magnet. The trigger assembly also includes a sensor configured to sense a magnetic field of the magnet. Movement of the trigger shoe rotates the magnet, and alters the magnetic field sensed by the sensor.

First claim

What is claimed is:

1. A trigger assembly for a power tool comprising:
a moveable plunger coupled having a first end and a second end, wherein the first end is coupled to a magnet;
a trigger shoe coupled to a second end of the moveable plunger; and
a sensor configured to sense a magnetic field of the magnet,
wherein movement of the trigger shoe rotates the magnet and alters the magnetic field sensed by the sensor.

2. The trigger assembly of claim 1 , wherein the sensor is electrically connected to a controller of the power tool, the controller configured to control an output of the power tool.

3. The trigger assembly of claim 2 , wherein the sensor is configured to output a signal to the controller based on the sensed magnetic field.

4. The trigger assembly of claim 3 , wherein the output is a voltage indicative of a position of the trigger shoe.

5. The trigger assembly of claim 1 , wherein the magnet is an annular magnet configured to rotate based on movement of the arm.

6. The trigger assembly of claim 5 , wherein the sensor is configured to sense a change in the magnetic field of the annular magnet in response to the annular magnet rotating.

7. The trigger assembly of claim 1 , further comprising:
a selector disposed on a surface of a housing of the trigger assembly;
a pin including a first end that is engageable with the selector and a second end that is coupled to a selector magnet; and
a selector sensor configured to sense a magnetic field of the selector magnet,
wherein axial motion of the selector rotates the selector magnet and alters the magnetic field sensed by the sensor.

8. The trigger assembly of claim 7 , wherein the selector sensor is configured to sense a polarity of the selector magnet and output a digital signal to a controller based on the sensed polarity.

9. The trigger assembly of claim 8 , wherein the controller is configured to execute an operating mode selected from a plurality of operating modes of the power tool based on the digital signal received from the selector sensor.

10. The trigger assembly of claim 9 , further comprising an arm having a first side that is moveably connected to the first end of the moveable plunger and a second side that is coupled to the magnet.

11. A method for controlling an output of an electric power tool, the method comprising:
actuating a trigger shoe of the electric power tool in a first linear direction;
converting linear movement of the movable plunger into a rotational movement of a movable arm in a first rotational direction;
rotating an annular magnet coupled to the movable arm in the first rotational direction;
sensing a parameter of a magnetic field generated by the annular magnet at a first magnetic sensor; and
controlling, via the controller, the output of the electric power tool based on the sensed parameter.

12. The method of claim 11 , wherein the output of the electric power tool is a rotational speed.

13. The method of claim 11 , wherein the sensed parameter is a magnetic flux density vector component.

14. The method of claim 11 , wherein the first magnetic sensor is an analog rotational magnetic field sensor.

15. The method of claim 11 , further comprising sensing a parameter of the magnetic field generated by the annular magnet at a second magnetic sensor, wherein the second magnetic sensor is a digital magnetic sensor.

16. The method of claim 15 , further comprising initiating a wake-up process for the controller based on the controller receiving an output of the second magnetic sensor.

17. A trigger assembly, comprising:
a trigger assembly including:
a housing;
a selector disposed on a surface of the housing;
a pin including a first end that is engageable with the selector and a second end that is coupled to a selector magnet; and
a selector sensor configured to sense a magnetic field of the selector magnet,
wherein axial motion of the selector rotates the selector magnet and alters the magnetic field sensed by the sensor.

18. The power tool of claim 17 , wherein the trigger assembly further comprises:
a trigger shoe configured to be actuated in a first linear direction, wherein actuation of the trigger shoe moves a movable plunger in the first linear direction,
a movable arm configured to rotate an annular magnet coupled to the movable arm in the first rotational direction, and
a magnetic sensor configured to sense a first parameter of a magnetic field generated by the annular magnet; and

a controller configured to receive the output voltage from the magnetic sensor and control an output of the power tool based on the sensed parameter.

19. The power tool of claim 18 , further comprising:
a second magnetic sensor configured to sense a second parameter of the annular magnet and transmit an output to the controller, wherein the second magnetic sensor is a digital magnetic sensor, and the second parameter is a polarity of the annular magnet.

20. The power tool of claim 19 , wherein the controller is further configured to initiate a wake-up process for the controller based on the controller receiving the output of the second magnetic sensor.

Assignees

• Milwaukee Electric Tool Corp

Inventors

• Merget Maxwell L
• Fieldbinder Douglas R
• Schneider Jacob P

Classifications

• H01H13/20

  Driving mechanisms · CPC title

• H01H13/14

  Operating parts, e.g. push-button · CPC title

• H01H3/50

  with indexing or locating means, e.g. indexing by ball and spring · CPC title

• H01H9/06

  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 · CPC title

• H03K17/97

  using a magnetic movable element · CPC title