Chain saw

Patent metadata

Field	Value
Publication number	US-9636840-B2
Application number	US-201314382262-A
Country	US
Kind code	B2
Filing date	Mar 6, 2013
Priority date	Mar 14, 2012
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

A chain saw is provided with an adjustment mechanism that adjusts the tension of a saw chain 4 attached along a guide bar 3 projecting from a main body 2 . The adjustment mechanism has a rotation shaft 55 that is provided with a feed screw, a moving element 70 that is moved on the rotation shaft 55 in an axial direction along with rotation of the rotation shaft 55 and moves the guide bar 3 forward/backward with respect to the main body 2 , and a transmission mechanism including an internal gear 51 provided on an inner peripheral surface of an adjustment dial 50 rotatably provided on the main body 2 and an external gear 52 disposed on an inner side of the adjustment dial 50 and engaged with the internal gear 51 . When the internal gear 51 is rotated along with rotation of the adjustment dial 50 , the rotation shaft 55 is rotated via the external gear 52.

First claim

The invention claimed is:

1. A chain saw comprising an adjustment mechanism that adjusts tension of a saw chain attached along a guide bar projecting from a main body,
wherein the adjustment mechanism includes:
a moving element that moves the guide bar forward/backward with respect to the main body; and
a transmission mechanism including:
a first gear that is provided on an inner peripheral surface of a first rotation member rotatably provided on the main body;
a second gear that is disposed on an inner side in a radial direction of the first rotation member and is engaged with and enclosed in the first gear;
a rotation shaft;
a third gear that is integrally rotated with the second gear; and
a fourth gear that is integrally rotated with the rotation shaft and is engaged with the third gear,

wherein when the first gear is rotated along with rotation of the first rotation member, the moving element is moved via the second gear,
wherein the moving element is moved on the rotation shaft in an axial direction along with rotation of the rotation shaft,
wherein the first gear and the second gear are spur gears, and the third gear and the fourth gear are bevel gears,
wherein the first gear and the second gear are disposed at positions overlapped with the first rotation member with respect to an axial direction of a rotation shaft of the first rotation member, and
wherein the third gear, the fourth gear, and the rotation shaft are disposed at positions not overlapped with the first rotation member with respect to an axial direction of the rotation shaft of the first rotation member.

2. The chain saw according to claim 1 ,
wherein the number of teeth of the first gear is greater than the number of teeth of the second gear.

3. The chain saw according to claim 2 ,
wherein a rotation axis of the first gear and the second gear and a rotation axis of the rotation shaft are orthogonal to each other.

4. The chain saw according to claim 1 , further comprising:
a second rotation member that shares a rotation axis with the first rotation member; and
a screw member that is projecting from the main body to penetrate through the guide bar and is provided with a male screw coupled to a female screw provided on the second rotation member,
wherein the guide bar is positioned between the main body and the second rotation member.

5. The chain saw according to claim 4 , further comprising:
a fixation member that is disposed around the screw member and between the guide bar and the second rotation member,
wherein the guide bar is sandwiched between the main body and the second rotation member via the fixation member.

6. The chain saw according to claim 4 ,
wherein the first rotation member has a discoid base part, a first sidewall part extending from a periphery of the base part toward the main body, and a second sidewall part extending from the periphery of the base part toward a direction opposite to the first sidewall part,
the first gear is formed on an inner peripheral surface of the first sidewall part of the first rotation member, and
the second rotation member is disposed on the base part of the first rotation member and on an inner side of the second sidewall part.

Assignees

• Hitachi Koki Kk

Inventors

• Saitoh Hiroyuki

Classifications

• B27B17/14

  Arrangements for stretching the chain saw · CPC title

• F16H7/06

  with chains · CPC title

• B27B17/08 Primary

  Drives or gearings; Devices for swivelling or tilting the chain saw · CPC title

• F16H7/14

  of a driving or driven pulley · CPC title

• B27B17/02

  Chain saws equipped with guide bar (B27B17/06 takes precedence) · CPC title