Work tool and transmission system thereof

Patent metadata

Field	Value
Publication number	US-12496697-B2
Application number	US-202218089718-A
Country	US
Kind code	B2
Filing date	Dec 28, 2022
Priority date	Dec 28, 2021
Publication date	Dec 16, 2025
Grant date	Dec 16, 2025

Abstract

A work tool and transmission system thereof. The transmission system comprises: a first shaft ( 250 ) and a second shaft ( 350 ), a near end ( 351 ) of the second shaft having a first mating part; a shaft coupler ( 600 ), a far-side part ( 620 ) of the shaft coupler having a second mating part matched in shape to the first mating part; and a coupling mechanism capable of directly or indirectly applying a coupling force to at least one of the first shaft, the second shaft and the shaft coupler; when the far-side part of the shaft coupler is aligned with the near end of the second shaft in the circumferential direction, the coupling force forces the first mating part to engage with the second mating part, so that the shaft coupler transmits rotational movement of the first shaft to the second shaft. The work tool comprises: a transmission system; a motive power head transmission-connected to the first shaft ( 250 ); and a working head transmission-connected to the second shaft ( 350 ).

First claim

The invention claimed is:

1 . Transmission system for a work tool, comprising:
a first shaft; a second shaft, a near end of the second shaft having a first mating part; and a shaft coupler, a far-side part of the shaft coupler having a second mating part matched in shape to the first mating part; wherein the transmission system further comprises a coupling mechanism capable of directly or indirectly applying a coupling force to at least one of the first shaft, the second shaft and the shaft coupler; wherein the shaft coupler is configured to transmit rotational movement of the first shaft to the second shaft when the far-side part of the shaft coupler is aligned with the near end of the second shaft in a circumferential direction such that the coupling force forces the first mating part to engage with the second mating part; wherein a near-side part of the shaft coupler comprises a first shaft hole for accommodating a far end of the first shaft, the far-side part of the shaft coupler comprises a second shaft hole for accommodating the near end of the second shaft; and wherein the far-side part of the shaft coupler further comprises a guide channel defined by an end wall of the shaft coupler extending between a far-end opening of the shaft coupler and the second shaft hole, a cross section of the guide channel gradually decreases in size from the far-end opening towards the second shaft hole; and wherein the coupling mechanism comprises a first biasing element arranged at least partially around the far end of the first shaft for applying a first axial biasing force to the shaft coupler and a second biasing element arranged at least partially around a near end of the first shaft for applying a second axial biasing force to the first shaft, and wherein the first shaft and the shaft coupler are configured to rotate until the far side part of the shaft coupler is aligned with the near end of the second shaft in the circumferential direction and one or both of the first axial biasing force and the second axial biasing force pushes the shaft coupler towards the far side such that the second shaft enters the second shaft hole.

2 . Transmission system according to claim 1 , wherein the first mating part comprises the first shaft and the first shaft hole having a non-circular cross section, the second mating part comprises the second shaft and the second shaft hole having the non-circular cross section, and when the far-side part of the shaft coupler is aligned with the near end of the second shaft in the circumferential direction, the second shaft can enter the second shaft hole.

3 . Transmission system according to claim 1 , wherein when the far-side part of the shaft coupler and the near end of the second shaft are in contact with each other but not aligned in the circumferential direction, the first axial biasing force of the first biasing element can be overcome by applying a pushing force to the second shaft, causing the shaft coupler to move a certain distance towards the near side.

4 . Transmission system according to claim 1 , wherein the near-side part of the shaft coupler and the far end of the first shaft are fixedly connected in such a way as to be unable to move relative to each other.

5 . Transmission system according to claim 1 , wherein the near-side part of the shaft coupler and the far end of the first shaft are connected in such a way as to be movable relative to each other in the axial direction.

6 . Transmission system according to claim 1 , wherein when the far-side part of the shaft coupler and the near end of the second shaft are in contact with each other but not aligned in the circumferential direction, the second shaft can push the shaft coupler to move towards the near side, while compressing the first biasing element.

7 . Transmission system according to claim 1 , wherein when the far-side part of the shaft coupler and the near end of the second shaft are in contact with each other but not aligned in the circumferential direction, the second shaft can push the first shaft to move towards the near side, while compressing the second biasing element.

8 . Transmission system according to claim 1 , wherein the first shaft is transmission-connected to a motive power head of the work tool, the second shaft is transmission-connected to a working head of the work tool, and optionally, at least one of the first shaft and the second shaft comprises multiple shaft segments transmission-connected to each other.

9 . Transmission system according to claim 2 , wherein the coupling mechanism comprises a magnetic element, the coupling force comprises a magnetic force applied to the shaft coupler and/or the second shaft by the magnetic element, and when the far-side part of the shaft coupler is aligned with the near end of the second shaft in the circumferential direction, the magnetic force forces the shaft coupler to move towards the far side, causing the second shaft to enter the second shaft hole.

10 . Transmission system according to claim 1 , wherein the transmission system further comprises:
a first tube, at least part of the first shaft being located in the first tube and rotatable relative to the first tube; a second tube, at least part of the second shaft being located in the second tube and rotatable relative to the second tube; a tube connector for connecting the first tube and the second tube, at least part of the shaft coupler being located in the tube connector; and a locking mechanism, comprising a positioning pin and a positioning hole, one of the positioning pin and positioning hole being located on the first tube or second tube, and the other being located on the tube connector; when the positioning pin enters or passes through the positioning hole, relative movement between the first tube or second tube and the tube connector is prevented, and the locking mechanism is in a locked position.

11 . Transmission system according to claim 10 , wherein the positioning pin is mounted on the second tube by means of a biasing component, and when the locking mechanism is in the locked position, the positioning pin extends through a hole formed in the second tube.

12 . Transmission system according to claim 11 , wherein the biasing component is pivotably mounted on the second tube by means of a fastener, the fastener comprising a protruding part located outside an outer wall of the second tube.

13 . Transmission system according to claim 12 , wherein the tube connector comprises a guide groove formed on an inner wall of the tube connector, the dimensions of the guide groove being designed to be suitable for accommodating and guiding the protruding part of the fastener.

14 . Transmission system according to claim 10 , wherein the locking mechanism further comprises an unlocking element which, when actuated, forces the positioning pin to leave the positioning hole.

15 . Transmission system according to claim 10 , wherein an inner wall of the tube connector defines a first connecting channel and a second connecting channel, the first connecting channel being used to receive a far end of the first tube, the second connecting channel being used to receive a near end of the second tube, and the first connecting channel and second connecting channel being separated by a flange; when mounting is complete, the near-side part of the shaft coupler is located in the first connecting channel, and the far-side part of the shaft coupler is located in the second connecting channel.

16 . Transmission system according to claim 10 , wherein the first biasing member comprises a fir

Assignees

• Techtronic Cordless Gp

Inventors

• Sabic Adis
• Lu xin ran
• Hu Ruo Yang

Classifications

• F16D2001/102

  the torque is transmitted via polygon shaped connections · CPC title

• F16D1/10

  Quick-acting couplings in which the parts are connected by simply bringing them together axially · CPC title

• F16D1/101

  without axial retaining means rotating with the coupling · CPC title

• B25F5/02

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

• A01G3/086

  Chain saws · CPC title