Power tool and method for starting the same

Patent metadata

Field	Value
Publication number	US-12059737-B2
Application number	US-202117193563-A
Country	US
Kind code	B2
Filing date	Mar 5, 2021
Priority date	Sep 18, 2018
Publication date	Aug 13, 2024
Grant date	Aug 13, 2024

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 actuatable by a user;
a current switch for turning on or off an 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 a start of the motor; the signal switch being arranged to connect with the trigger mechanism to be actuated by the trigger mechanism,
wherein the signal switch comprises a first signal switch operably coupled to the trigger mechanism to be actuated by the trigger mechanism when the trigger mechanism is actuated and a second signal switch operably coupled to the trigger mechanism to be actuated by the trigger mechanism when the trigger mechanism is actuated, 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, and
wherein, when the trigger mechanism is released from the end position to the initial position, an on-off state of the second signal switch, an on-off state of the first signal switch, and an on-off state of the current switch, change sequentially, the on-off state of the first signal switch is changed to output a signal to the control module to brake the motor, and the on-off state of the current switch is changed to disconnect the electrical connection between the motor and the power supply module.

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 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, 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.

5. 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 detection circuit being electrically connected to the signal switch and the control module.

6. 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.

7. The power tool of claim 1 , 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.

8. The power tool of claim 7 , 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.

9. 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.

10. The power tool of claim 9 , wherein the predetermined time period ranges from 50 milliseconds to 200 milliseconds.

11. The power tool of claim 9 , 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.

12. The power tool of claim 11 , wherein the first switch element is a field effect transistor.

13. The power tool of claim 9 , 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.

14. The power tool of claim 13 , 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.

15. The power tool of claim 14 , 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

• H02P1/16

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

• B25F5/02

  Construction of casings, bodies or handles {(B25F5/006, B25F5/008 take precedence)} · CPC title

• H02P6/21

  Open loop start · CPC title

• H02P29/68

  based on the temperature of a drive component or a semiconductor component · CPC title

• H02P1/42

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