Impact tool

Patent metadata

Field	Value
Publication number	US-10022852-B2
Application number	US-201514714719-A
Country	US
Kind code	B2
Filing date	May 18, 2015
Priority date	May 16, 2014
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

An electrical hammer (100) comprises a main housing (101), a hand grip (500) connected to the main housing (101) via a compression coil spring (321). In the electrical hammer (100), a hammer bit (119) is driven by a first motion converting mechanism (120) and thereby a hammering operation is performed. During the hammering operation, the hand grip (500) is moved against the main housing (101) in a state that biasing force of the compression coil spring (321) is applied on the hand grip (500). Further, the electrical hammer (100) comprises a second motion converting mechanism (220) which drives a counterweight (231).

First claim

The invention claimed is:

1. An impact tool which drives a tool bit in a longitudinal direction of the tool bit and performs a predetermined operation, comprising:
a motor which includes a motor shaft,
a driving mechanism which is driven by the motor and drives the tool bit,
a main housing which houses the driving mechanism,
a handle which includes a grip portion extending in a cross direction crossing the longitudinal direction of the tool bit, the handle being configured to be moved with respect to the main housing,
a biasing member which is arranged between the main housing and the handle and applies biasing force on the handle,
a weight which is housed in the main housing and movable with respect to the main housing,
a first crank mechanism which has a first rotation shaft and a first eccentric shaft which is offset from the rotational center of the first rotation shaft, the first crank mechanism being configured to be driven by the motor and drive the driving mechanism, and
a second crank mechanism which has a second rotation shaft and a second eccentric shaft which is offset from the rotational center of the second rotation shaft, the second crank member being configured to be driven by the motor and drive the weight such that the weight is relatively moved with respect to the main housing,
wherein the weight is configured to reduce vibration generated on the main housing during the operation by relatively moving with respect to the main housing,
the handle is configured to prevent vibration transmission from the main housing to the handle during the operation by relatively moving with respect to the main housing in a state that the biasing force of the biasing member is applied on the handle, and
the first and second eccentric shafts are disposed such that when the first eccentric shaft is positioned at the closest position to the tool bit in the longitudinal direction of the tool bit within its movable range, the second eccentric shaft is positioned at a position other than the closest position to the tool bit in the longitudinal direction of the tool bit and the most distant position from tool bit in the longitudinal direction of the tool bit within its movable range.

2. The impact tool according to claim 1 , comprising an intervening member which is arranged between the weight and the second eccentric shaft,
wherein the weight is driven by the second crank mechanism via the intervening member.

3. The impact tool according to claim 2 , wherein the intervening member is provided as an elastically deformable elastic member,
wherein the weight is driven by the second crank mechanism via the elastic member.

4. The impact tool according to claim 1 , wherein a moving amount of the second eccentric shaft in the longitudinal direction of the tool bit is defined to be equal to a moving amount of the weight in the longitudinal direction of the tool bit.

5. The impact tool according to claim 1 , wherein the weight is connected directly to the second eccentric shaft.

6. The impact tool according to claim 1 , wherein the motor is arranged such that the motor shaft crosses the axial line of the tool bit.

7. The impact tool according to claim 1 , wherein the driving mechanism comprises a hammering element for hammering the tool bit, and a cylinder which holds the hammering element slidably therein and is coaxial with the axial line of the tool bit, and
the weight is arranged outside of the cylinder so as to surround at least part of the cylinder.

8. The impact tool according to claim 7 , wherein the gravity center of the weight is arranged so as to overlap with the cylinder on a cross section perpendicular to the axial line of the tool bit.

9. The impact tool according to claim 1 , wherein the driving mechanism comprises a hammering element for hammering the tool bit, and a cylinder which holds the hammering element slidably therein and is coaxial with the axial line of the tool bit, and
the weight comprises a pair of weight components which are arranged at both outsides of the cylinder with respect to a plane including the axial line of the tool bit and a grip portion extending line, respectively.

10. The impact tool according to claim 1 , wherein the driving mechanism comprises a hammering element for hammering the tool bit, and a cylinder which holds the hammering element slidably therein and is coaxial with the axial line of the tool bit, and
the weight is arranged in at least one of outer regions of the cylinder in the crossing direction.

11. The impact tool according to claim 1 , wherein the handle is relatively moved with respect to the main housing in the longitudinal direction of the tool bit.

12. The impact tool according to claim 11 , comprising a rotation support part which rotatably supports the handle with respect to the main housing such that the handle is rotated on a plane including the axial line of the tool bit and a grip part extending line,
wherein the biasing member is arranged on the plane distant from the rotation support part.

13. The impact tool according to claim 1 , comprising an outer housing which covers at least a part of a region of the main housing which houses the driving mechanism and the motor,
wherein the handle is connected to the outer housing and integrally moved with the outer housing with respect to the main housing.

14. The impact tool according to claim 13 , comprising an auxiliary handle attachable part to which an auxiliary handle is detachably attached,
wherein the auxiliary handle attachable part is connected to the outer housing and integrally moved with the handle connected to the outer housing with respect to the main housing.

15. The impact tool according to claim 1 , wherein the first rotation shaft and the second rotation shaft are arranged coaxially with each other.

16. The impact tool according to claim 1 , comprising a controller which controls rotation speed of the motor to be driven at substantially constant rotation speed.

17. The impact tool according to claim 1 , wherein a phase of the first eccentric shaft and a phase of the second eccentric shaft is set to approximately 90 degrees.

18. An impact tool which drives a tool bit in a longitudinal direction of the tool bit and performs a predetermined operation, comprising:
a motor which includes a motor shaft,
a driving mechanism which is driven by the motor and drives the tool bit,
a main housing which houses the driving mechanism,
a handle which includes a grip portion extending in a cross direction crossing the longitudinal direction of the tool bit, the handle being configured to be moved with respect to the main housing,
a biasing member which is arranged between the main housing and the handle and applies biasing force on the handle,
a weight which is housed in the main housing and movable with respect to the main housing,
a first crank mechanism which has a first rotation shaft and a first eccentric shaft which is offset from the rotational center of the first rotation shaft, the first crank mechanism being configured to be driven by the motor and drive the driving mechanism,
a second crank mechanism which has a second rotation shaft and a second eccentric shaft which is offset from the rotational center of the second rotation shaft, the second crank member being configured to be driven by the motor and drive the weight such that the weight is relatively moved with respect to the main housing, and
an outer housing which covers at least a part of a region of the main housing which houses the driving mechanism and t

Assignees

• Makita Corp

Inventors

• Ikuta Hiroki
• Machida Yoshitaka
• Furusawa Masanori

Classifications

• B25D2250/245

  Spatial arrangement of components of the tool relative to each other · CPC title

• B25D11/04

  in which the tool bit or anvil is hit by an impulse member · CPC title

• B25D2250/175

  Phase shift of tool components · CPC title

• B25D2250/121

  Housing details · CPC title

• B25D2217/0088

  being mechanically-driven · CPC title