# US 8,770,315 B2 · Impact tool

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- Number: US 8,770,315 B2
- Document ID: US8770315B2
- Status: Granted
- Kind: B2
- Application number: 13/110,200
- Filed: 2011-05-18
- Published: 2011-12-01
- Granted: 2014-07-08
- Earliest claimed: 2010-05-25
- Assignees: Makita Corporation
- Applicants: Hajime Takeuchi; Masanori Furusawa; Naoki Soeda
- Inventors: Hajime Takeuchi; Masanori Furusawa; Naoki Soeda
- Web page: https://patentgrep.com/patent/US8770315B2

## CPC

- B25D 17/088: {with radial movable locking elements co-operating with bit shafts specially adapted therefor}
- B25D 17/00: Details of, or accessories for, portable power-driven percussive tools {(details or components, e.g. casings, bodies, of portable power-driven tools not particularly related to the operation performed B25F5/00)}
- B25D 2217/0038: Locking members of special shape
- B25D 2217/0065: Use of dust covers
- B25D 2222/57: Elastomers, e.g. rubber
- B25D: PERCUSSIVE TOOLS {(percussive machines for forging B21J; hand-held drilling machines, in general B23B45/00, for wood B27C3/08; drilling machines, used for mining or quarrying, with reciprocating tool which is turned intermittently when out of contact with the working face E21B1/00)}

## Abstract

An impact tool includes a bit holding device with an elongate tool holder having a bit holding hole with a tool bit, an outer shell component forming an outer shell of the bit holding device and mounted onto a front end portion of the tool holder, a stopper fitted onto the tool holder and prevented from moving in a longitudinal direction of the tool holder, and prevents the outer shell component from becoming detached from the front end of the tool holder, and an opening prevention member disposed outward of a center position of the stopper in the longitudinal direction of the tool holder and opposed to an outer surface of the stopper in a direction transverse to the longitudinal direction of the tool holder, and prevents the stopper from opening in the direction transverse to the longitudinal direction of the tool holder.

## Claims

### Claim 1

An impact tool comprising a tool body and a bit holding device mounted onto a front end region of the tool body to perform a predetermined operation at least by linearly driving a tool bit held by the bit holding device,
wherein the bit holding device comprises:
an elongate tool holder having a bit holding hole into which the tool bit is removably inserted,
an outer shell component which forms an outer shell of the bit holding device and is mounted onto a front end portion of the tool holder by moving the outer shell component from the front end of the tool holder toward the tool body,
a stopper which is fitted onto the tool holder such that the stopper is prevented from moving in a longitudinal direction of the tool holder, and serves to prevent the outer shell component from slipping out of the front end of the tool holder, and
an opening prevention member which is disposed outward of a center position of the stopper in the longitudinal direction of the tool holder and opposed to an outer surface of the stopper in a direction transverse to the longitudinal direction of the tool holder, and is configured to prevent the stopper from opening in the direction transverse to the longitudinal direction of the tool holder when impact is transmitted from the tool holder to the stopper during idle driving,
wherein the stopper and the opening prevention member are normally disposed in non-contact with each other.

### Claim 2 (depends on 1)

The impact tool as defined in claim 1, wherein the tool holder has a protruding front end which protrudes from a front end of the outer shell component, the bit holding device further has a rubber covering fitted onto the protruding front end, and the opening prevention member is integrated with the covering and disposed outward of the stopper when the covering is fitted onto the protruding front end of the tool holder.

### Claim 3 (depends on 1)

The impact tool as defined in claim 1, wherein the opening prevention member is made of metal.

### Claim 4 (depends on 1)

The impact tool as defined in claim 1, wherein the opening prevention member is formed by a ring closed in a circumferential direction.

### Claim 5 (depends on 4)

The impact tool as defined in claim 4, wherein the ring has a rectangular section, and its inner circumferential surface transverse to a direction transverse to the longitudinal direction of the tool holder is opposed to an outer surface of the stopper.