Power tool and method for starting the same

Patent metadata

Field	Value
Publication number	US-2021187635-A1
Application number	US-202117193563-A
Country	US
Kind code	A1
Filing date	Mar 5, 2021
Priority date	Sep 18, 2018
Publication date	Jun 24, 2021
Grant date	—

Abstract

A power tool includes a tool accessory, a motor, a control module, a power supply, and an operating switch. The operating switch includes a trigger mechanism, a current switch coupled to the trigger mechanism to be actuated by the trigger mechanism for connecting and disconnecting the electrical connection between the power supply module and the motor, and a signal switch coupled to the trigger mechanism to be actuated by the trigger mechanism at least configured to output a control signal to the control module to control the start of the motor.

First claim

What is claimed is:

1 . A power tool comprising:
a tool accessory; a motor configured to drive the tool accessory; a control module configured to control the motor; a power supply module configured to provide electric power for the motor and the control module; and an operating switch, comprising: a trigger mechanism; a current switch for turning on or off the electrical connection between the power supply module and the motor; the current switch being coupled to the trigger mechanism to be actuated by the trigger mechanism; and a signal switch at least configured to output a control signal to the control module to control the start of the motor; the signal switch being arranged to connect with the trigger mechanism to be actuated by the trigger mechanism.

2 . The power tool of claim 1 , wherein the current switch and the signal switch are actuated by the trigger mechanism in a different order.

3 . The power tool of claim 1 , wherein the signal switch comprises a signal switch, when the trigger mechanism is actuated to reach a first position, the current switch is actuated to enable the electrical connection between the power supply module and the power tool, when the trigger mechanism is actuated to reach a second position, the signal switch is actuated to output a signal to the control module to control the motor to start, and, when the trigger mechanism is actuated from an initial position to an end position, the trigger mechanism sequentially reaches the first position and the second position.

4 . The power tool of claim 1 , wherein the signal switch comprises a first signal switch coupled to the trigger mechanism to be actuated by the trigger mechanism and a second signal switch coupled to the trigger mechanism to be actuated by the trigger mechanism, when the trigger mechanism is actuated from an initial position to an end position, the trigger mechanism sequentially reaches a first position, a second position, and a third position, when the trigger mechanism is actuated to reach the first position, the first signal switch is actuated, when the trigger mechanism is actuated to reach the second position, the current switch is actuated to electrically connect the motor and the power supply module, and, when the trigger mechanism is actuated to reach the third position, the second signal switch is actuated to output a signal to the control module to start the motor.

5 . The power tool of claim 4 , wherein, when the trigger mechanism is actuated to reach the first position, the first signal switch is actuated to electrically connect the power supply module and the control module.

6 . The power tool of claim 4 , wherein, when the trigger mechanism is released from the end position to the initial position, the trigger mechanism sequentially reaches a fourth position, a fifth position, and a sixth position, when the trigger mechanism is actuated to reach the fourth position, the on-off state of the second signal switch is changed, when the trigger mechanism is actuated to reach the fifth position, the on-off state of the first signal switch is changed to output a signal to the control module to brake the motor and, when the trigger mechanism is actuated to reach the sixth position, the on-off state of the current switch is changed to disconnect the electrical connection between the motor and the power supply module.

7 . The power tool of claim 6 , wherein the fifth position is closer to the initial position with respect to the second position.

8 . The power tool of claim 1 , further comprising a signal switch detection circuit configured to detect the state of the signal switch, the signal switch state detection circuit being electrically connected to the signal switch and the control module.

9 . The power tool of claim 1 , wherein the current switch has at least two pairs of contacts and each pair of the contacts is connected by a metal conductor.

10 . The power tool of claim 4 , further comprising a housing, which is formed with a handle, wherein a plane that bisects the handle is defined as a handle central plane and the first signal switch and the second signal switch are distributed on both sides of the handle central plane.

11 . The power tool of claim 10 , wherein a projection of the first signal switch on the handle central plane and a projection of the second signal switch on handle central plane at least partially overlap.

12 . The power tool of claim 1 , further comprising a power storage element, a drive circuit electrically connected to the motor and the power supply module, and a first switch circuit, connected in series with the power storage element and then connected in parallel with the drive circuit, wherein the control module is electrically connected with the drive circuit and the first switch circuit and the control module is configured to delay turning on the first switch circuit for a predetermined time period after the current switch is turned on.

13 . The power tool of claim 12 , wherein the predetermined time period ranges from 50 milliseconds to 200 milliseconds.

14 . The power tool of claim 12 , wherein the first switch circuit comprises a first switch element connected in series with the power storage element and electrically connected with the control module.

15 . The power tool of claim 14 , wherein the first switch element is a field effect transistor.

16 . The power tool of claim 12 , further comprising a second switch circuit connected in parallel with the first switch circuit and electrically connected with the control module, the first switch circuit allows a first current to flow therethrough, the second switch circuit allows a second current to flow therethrough, a current value of the first current is greater than a current value of the second current, and the control module is further configured to, after the current switch is turned on and before the first switch circuit is turned on, turn on the second switch circuit to allow the power storage element to be charged with the second current.

17 . The power tool of claim 16 , wherein the second switch circuit comprises a second switch element electrically connected to the control module and a current limiting element connected in series with the second switch element.

18 . The power tool of claim 17 , wherein the second switch element is a field effect transistor and the current limiting element is a resistor.

Assignees

• Nanjing Chervon Ind Co Ltd

Inventors

• Lu Bing
• Yang Xin
• Yang Yuwei
• Zhou Yi
• Xu Tianxiao
• Duan Junya

Classifications

• B25B21/00

  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 title

• B23D45/16 Primary

  Hand-held sawing devices with circular saw blades · CPC title

• H02P1/16

  for starting dynamo-electric motors or dynamo-electric converters · CPC title

• H02P1/26

  for starting an individual polyphase induction motor · CPC title

• H02P1/42

  for starting an individual single-phase induction motor {(H02P27/04 takes precedence)} · CPC title