JPH06226703A - Saw chain of chain saw - Google Patents

Abstract

PURPOSE:To prolong the service life of tooth point without lowering the toughness and strength of a cutter link by a method wherein an outward projecting cutting blade part is provided on the cutter link on saw chain and further super- sub zero treatment consisting of the immersion in liquid nitrogen and the like after the quenching and tempering of the cutter link is performed. CONSTITUTION:Saw chain rotatingly driven which an engine round the outer periphery of a guide bar 5, which is forward protrudingly fixed on one side of a main body case for covering the engine, is slidably engaged into a chain saw. The saw chain is formed by successively and rockably connecting connectors 21, which consist of tie straps 19 and 19 connected and fixed by the front and rear rivets 17 on both the sides of the driving links, with the center driving links 23 journaled onto the rivets 17. Further, some of the tie straps 19 are substituted by steel cutter links 27, each of which is equipped with an outward projecting cutting blade part 25. Furthermore, the cutter link 27 is subjected to super-sub zero treatment consisting of the immersion in liquid nitrogen after the quenching and tempering of the link.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a guide bar which is fixed to one side of a main body case for covering an engine and projects forward, and a saw chain which is wound around the outer periphery of the guide bar and is rotated by driving the engine. It relates to saw chains in chain saws.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 4, in a saw chain, a connecting body 21 composed of tie straps (connecting pieces) 19 and 19 on both sides connected and fixed by a rivet 17 is pivotally attached to the rivet 17. The tie strap 1 is connected by the drive link 23 sequentially and rotatably.
9 is replaced with a cutter link 27 having a blade portion 25 outward (opposite to the guide bar) at appropriate intervals, and the drive link 23 is slidable in a groove portion 29 provided on the outer periphery of the guide bar 5. An engaging portion 31 that engages with the drive sprocket 35 and rotates and drives the saw chain by engaging with the drive sprocket 35 is formed so as to project inward (toward the guide bar).

Conventionally, this cutter link 27 has a blade portion 25.
The steel material whose strength and hardness have been increased by heat treatment has been used because it requires the hardness of the above.

[0004]

Conventionally, in order to increase the hardness of the cutter link 27 and reduce the wear of the blade portion 25, if a material for high hardness is used, the toughness may be lowered and the saw chain may be broken. When used as a link, there was a risk that the saw chain would break.

[0005]

DISCLOSURE OF THE INVENTION The present invention is intended to improve the wear resistance of the blade portion as much as possible without lowering the strength and toughness of the cutter link. Ultra-subzero treatment such as immersion in liquid nitrogen is performed to change the retained austenite into martensite, thereby further increasing the wear resistance of the blade.

Further, in the second item, after the ultra-subzero treatment, a hard compound or a hard film such as chrome plating is added to prolong the life of the blade.

The hard film referred to in the present invention is (1) T
A film formed by physical vapor deposition of iN, TiCN or the like, (2) a film formed by electrodeposition of hard particles such as diamond or CBN with Ni or the like, or a composite (dispersion) in which these hard particles are mixed.
plating. (3) Or hard plating such as hard chrome plating. And the like are added to the surface of the blade.

[0008]

[Operation] When working, trees are cut by the blade of the saw chain that rotates around the guide bar by driving the engine while holding the front and rear handles, but the cutter link uses a material with high strength and toughness. Therefore, it is not broken and the blade is less worn.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

The chain saw 1 is constructed as follows. That is, the guide bar 5 projects forward and is fixed to one side of the main body case 3 that covers the engine (not shown), and the saw chain 7 that rotates around the outer circumference of the guide bar 5 and is rotated by the drive of the engine is slidable. Engaged. A front handle 9 is provided at the front part of the body case 3, a rear handle 11 is provided at the rear part thereof, a guard plate 13 for protecting a worker's hand is provided in front of the front handle 9, and the rear handle 11 is provided at the rear handle 11. A throttle lever 15 is provided.

The saw chain 7 is constructed as follows. That is, the tie straps (connecting pieces) 19 on both sides, which are connected and fixed by the two front and rear rivets 17, 17,
A connecting body 21 composed of 19 is connected to a rivet 17 by a central drive link 23 so as to be swingable in sequence. The tie strap 19 is a steel cutter link 27 having a blade portion 25 on the outside (the direction opposite to the guide bar).
Has been replaced. The drive link 23 is formed with an engaging portion 31 slidably engaged with a groove portion 29 provided on the outer periphery of the guide bar 5 so as to project inward (in the direction of the guide bar 5). The engaging portion 31 is provided with a driven sprocket 33 rotatably provided on the front portion of the guide bar 5 by a ball bearing 32, grooves 29, 29 formed on the upper and lower edges of the guide bar 5, and close to the rear end. The saw chain 7 is rotated around the guide bar 5 by engaging with a drive sprocket 35 that rotates by driving the engine.

After the quenching and tempering, the cutter link 27 is subjected to a super-subzero treatment in which it is immersed in liquid nitrogen, and a hard film 39 made of a hard compound is added to the blade portion 25.

An operator grips the front handle 9 and the rear handle 11 with both hands, and cuts a tree or the like by the blade portion 25 of the saw chain 7 rotating around the guide bar 5 by driving the engine.

[0014]

According to the present invention, the retained austenite is converted to martensite, the structure is refined, the toughness is improved by the precipitation of fine carbide, or the stress is reduced by uphill quenching, as compared with the conventional surface hardening. In addition, the wear resistance of the blade portion can be improved, and the life of the blade edge can be extended without lowering the toughness and strength of the cutter link.

[Brief description of drawings]

FIG. 1 is a perspective explanatory view of a chain saw including a saw chain according to the present invention.

2A is a side view of a saw chain near a drive sprocket, FIG. 2B is a front sectional view taken along line II of FIG.
(c) is a sectional view taken along line II-II in (a).

3A is a side view of a saw chain near a driven sprocket, and FIG. 3B is a front sectional view taken along line III-III in FIG. 3A.

FIG. 4 is an exploded perspective view of the saw chain.

FIG. 5 is an enlarged view of a cutter link according to the present invention, in which (a) is a side view and (b) is IV-IV in (a).
It is a front sectional view of a line.

[Explanation of symbols]

 1 Chain Saw 3 Body Case 5 Guide Bar 7 Saw Chain 23 Drive Link 25 Blade 27 Cutter Link 37 Hardened Layer 39 Hard Film

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[Procedure amendment]

[Submission date] April 28, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006] In the second term, after super sub-zero treatment, Opposition
The life of the blade is extended by adding surface hardening such as quench hardening or a hard compound or a hard film such as chrome plating.

Claims (2)

[Claims] 1. A guide bar 5 fixed to one side of a main body case 3 for covering an engine and projecting forward, and a saw chain 7 wound around the outer periphery of the guide bar 5 and rotated by the drive of the engine. In the chain saw, a blade portion 25 protruding outward from the steel cutter link 27 of the saw chain 7 is provided, and ultra-subzero treatment such as quenching and tempering the cutter link 27 and immersing in liquid nitrogen is performed. A saw chain with a characteristic saw. 2. The saw chain of a chain saw according to claim 1, wherein a surface of the blade portion 25 after the ultra-subzero treatment is hardened by impact hardening, and a hard film 39 made of hard chrome or a hard compound is added.