Handheld power tool and impact block return device thereof

Patent metadata

Field	Value
Publication number	US-9868196-B2
Application number	US-201514724053-A
Country	US
Kind code	B2
Filing date	May 28, 2015
Priority date	Jun 5, 2014
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

The present invention provides a handheld power tool having an impact block and an impact block return device. The impact block has a plurality of continuous teeth arranged along a lengthwise direction of the impact block. The impact block return device comprises a gearwheel engaged with the teeth of the impact block; a ratchet wheel rotating simultaneously with the gearwheel; and a clamping member operated in a first state and a second state, the clamping member contacting the ratchet wheel in the first state and the clamping member being separated from the ratchet wheel in the second state; wherein the impact block only can do a single-directional movement when the clamping member contacts the ratchet wheel in the first state. The present invention can improve stability of the retraction process of the impact block (e.g., a firing pin).

First claim

What is claimed is:

1. A handheld power tool, having a main body, a nail magazine, an impact block, and an impact block return device, the main body having an exit at one end thereof, the exit communicating with the nail magazine and the impact block return device, the main body having a compressed air chamber at the other end thereof, the compressed air chamber accommodating the impact block, the impact block having a plurality of continuous teeth arranged along a lengthwise direction of the impact block, the impact block return device comprising:
a gearwheel adjacent to and engaged with the teeth of the impact block;
a ratchet wheel connecting to the gearwheel and rotating simultaneously with the gearwheel; and
a clamping member disposed at a position corresponding to the ratchet wheel and located away from the teeth of the impact block, the clamping member being operated in a first state and a second state, the clamping member contacting the ratchet wheel in the first state and the clamping member being separated from the ratchet wheel in the second state;
wherein the impact block only can do a single-directional movement when the clamping member contacts the ratchet wheel in the first state.

2. The handheld power tool according to claim 1 , wherein the impact block return device further comprises:
a power transmission assembly for driving the gearwheel and the ratchet wheel to rotate, wherein the power transmission assembly only can make the gearwheel and the ratchet wheel do a unidirectional rotation.

3. The handheld power tool according to claim 2 , wherein the power transmission assembly comprises:
a driven cam rotating simultaneously with the gearwheel and the ratchet wheel; and
an actuating cam driven by an electric motor, wherein the actuating cam drives the driven cam only when the actuating cam rotates along a particular direction.

4. The handheld power tool according to claim 3 , wherein the gearwheel, the ratchet wheel, and the driven cam have a same rotation axis.

5. The handheld power tool according to claim 1 , wherein the impact block return device further comprises:
an electromagnetic component for controlling the clamping member such that the clamping member changes between the first state and the second state.

6. The handheld power tool according to claim 1 , wherein during the impact block is actuated by a power source and thus moves from a start position to a stop position, the clamping member is at the second state separating from the ratchet wheel.

7. The handheld power tool according to claim 1 , wherein during the impact block moves from a stop position back to a start position, the clamping member is at the first state contacting the ratchet wheel.

8. An impact block return device for retracting an impact block having a plurality of continuous teeth arranged along a lengthwise direction of the impact block, the impact block return device comprising:
a gearwheel engaged with the teeth of the impact block;
a driven cam coupled to the gearwheel and rotating simultaneously with the gearwheel, the driven cam having a plurality of protruding blocks disposed on a wheel face thereof, the protruding blocks being annularly arranged at intervals;
an actuating cam driven by an electric motor, for driving the driven cam; and
a clamping member disposed at a position corresponding to the driven cam and located away from the teeth of the impact block, the clamping member being operated in a first state and a second state, the clamping member being located between any two protruding blocks of the driven cam in the first state and the clamping member being moved away from a moving track of the protruding blocks of the driven cam in the second state;
wherein the impact block only can do a single-directional movement when the clamping member is located between any two protruding blocks of the driven cam in the first state.

9. The impact block return device according to claim 8 , wherein the actuating cam drives the driven cam only when the actuating cam rotates along a particular direction.

10. The impact block return device according to claim 8 , wherein the gearwheel and the driven cam have a same rotation axis.

Assignees

• Basso Ind Corp

Inventors

• Chien Chia-Yu

Classifications

• B25C1/06 Primary

  operated by electric power · CPC title

• B25C1/047 Primary

  Mechanical details · CPC title