JP4469028B2 - Chainsaw - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a chainsaw provided with a chain for cutting wood or the like.
[0002]
[Prior art]
A conventional example of a conventional chain saw will be described with reference to FIGS. FIG. 3 is a front view of a drive unit of a conventional chain saw. FIG. 4 is a partial sectional side view of a conventional chain saw driving section.
[0003]
3 and 4, the chain saw 21 includes a switch 22 for turning on / off the power source, a grip portion 23 that supports the main body of the chain saw 21, a drive unit 30 that includes a motor that rotates a sprocket described later, The gear portion 26 that is mechanically connected, the star-shaped sprocket 27 that is connected to the gear portion 26 and has several protrusions on the outer periphery, and the protrusions on the outer periphery of the sprocket 27 are engaged with each other. The attached ring-shaped chain 24, the guide bar 25 on which the chain 24 is disposed on the outer periphery, the sprocket 27 that prevents the sprocket 27 from coming off and the guide bar 25 is fixed, and the sprocket 27 And a protective cover 29 that protects the attachment portion of the chain 24.
[0004]
The protective cover 29 is formed in a box shape with a part opened, and the chain 24 disposed on the guide bar 25 protrudes from the opening of the protective cover 29.
[0005]
When the switch 22 of the gripping part 23 is turned on and power is supplied to the chain saw 21, the motor of the drive part 30 rotates, and the rotational force of this motor is transmitted to the sprocket 27 via the gear. When the sprocket 27 rotates, the chain 24 engaged with the protrusion of the sprocket 27 is guided by the guide bar 25 and rotates around the outer periphery of the sprocket 27 and the guide bar 25. And wood etc. can be cut | disconnected with the tooth | gear part 24a provided in the outer periphery of the chain 24. FIG.
[0006]
[Problems to be solved by the invention]
When the chain saw with the above configuration is driven, if the chain is removed from the sprocket due to abnormal external force applied to the chain, guide bar, etc., the chain will jump out of the chain saw body, and May cause damage.
[0007]
[Means for Solving the Problems]
Therefore, according to the present invention, a ring-shaped chain provided with a tooth portion for cutting wood or the like, a protective cover that covers and protects the non-cut portion of the chain, and the chain is disposed on the outer periphery, and the chain is rotated. A guide bar that supports movement, a sprocket that meshes with the chain and rotates the chain, and is housed in the protective cover, the guide bar is fixed to the chain saw body, and the meshing part of the chain and sprocket The sprocket support includes a sprocket support, a guide bar fixing bolt that fixes the sprocket support and the guide bar, and a drive unit that drives the sprocket, and protects the meshed portion of the chain and the sprocket in the sprocket support. the outer periphery of the portion to which, to be larger than the outer periphery of the teeth of the chain, the Idoba and is extended in the opposite direction, and the guide and the bar screw portion of the fixing bolt long, a part of the opening of the protective cover to provide a chain saw, characterized in that plugged in this screw portion.
[0008]
[Action]
The diameter of a part or all of the sprocket support attached to one end face of the sprocket and fixing the sprocket is made larger than the diameter of the sprocket to prevent the chain from coming off from the sprocket. Even if the screw part of the guide bar fixing bolt that fixes the sprocket support and the guide bar is lengthened and closed so as to cross part of the opening of the protective cover, the chain cover is removed. Prevents popping out.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view of a chainsaw according to the present invention. FIG. 2 is a partial cross-sectional side view of the drive portion of the chain saw according to the present invention.
[0010]
1 and 2, a chain saw 1 is similar to a conventional chain saw in that a gripping portion 2, a drive portion 4 having a motor for rotating the chain 3, and a gear portion 5 mechanically connected to the motor are provided. A star-shaped sprocket 6 connected to the gear portion 5; a ring-shaped chain 3 meshed with the sprocket 6; a guide bar 7 on which the chain 3 is disposed on the outer periphery; and a sprocket 6 The sprocket support 8 that fixes the guide bar 7 and the protective cover 9 that protects the attachment portion between the sprocket 8 and the chain 3 are provided.
[0011]
The diameter of the sprocket support 8 at the meshing portion of the chain 3 and the sprocket 6 is made larger than the outer diameter of the sprocket 6 to the tip of the sprocket 6 or the outer diameter of the chain 3 at the position meshed with the sprocket 6. .
[0012]
Further, the outer periphery of the sprocket support 8 does not need to be increased over the entire outer diameter of the sprocket 6 to the tip of the projection, and the chain 3 can be prevented from coming off if only a part of the outer periphery is increased.
[0013]
Further, by increasing the length of the threaded portion 10a of the bolt 10 that fixes the sprocket support 8 and the guide bar 7, the clearance is narrowed by the opening of the protective cover 9 and the threaded portion 10a, and the chain 3 Even when the sprocket 6 is detached from the sprocket 6, the chain 3 is caught by the opening of the protective cover 9 and the screw portion 10 a so that it does not jump out of the protective cover 9.
[0014]
With the above configuration, the shape of the sprocket support in the protective cover and the length of the threaded part of the bolt are only changed, so there is little change in the appearance of the chain saw, and the shape of existing parts is changed. Because it is just, it can be made cheaper.
[0015]
【The invention's effect】
Since the present invention has little change in appearance and has a simple structure, the chain can be prevented from coming off at low cost. Therefore, the safety of the chainsaw is improved.
[0016]
[Brief description of the drawings]
FIG. 1 is a front view of a chainsaw according to the present invention.
FIG. 2 is a partial side sectional view of a drive unit of a chain saw according to the present invention.
FIG. 3 is a front view of a conventional chain saw drive unit.
FIG. 4 is a partial side sectional view of a conventional chain saw drive unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 21 ... Chain saw 2, 23 ... Holding part 3, 24 ... Chain 4, 30 ... Drive part 5, 26 ... Gear part 6, 27 ... Sprocket 7, 25 ... Guide bar 8, 28 ... Sprocket support 9, 29 ... Protection Cover 10 ... Bolt 22 ... Switch

Claims (1)

An annular chain provided with teeth for cutting wood, etc.
A protective cover that covers and protects the uncut portion of the chain;
A guide bar disposed on an outer periphery of the chain for supporting the rotation of the chain;
A sprocket meshed with the chain and rotating the chain;
A sprocket support that is housed in the protective cover, fixes the guide bar to a chain saw body, and protects the meshing part of the chain and the sprocket;
A guide bar fixing bolt for fixing the sprocket support and the guide bar;
A drive unit that drives the sprocket,
In the sprocket support, the outer periphery of the portion protecting the meshing part of the chain and the sprocket is extended in the direction opposite to the guide bar so as to be larger than the outer periphery of the tooth portion of the chain ,
A chain saw characterized in that the threaded portion of the guide bar fixing bolt is lengthened and a part of the opening of the protective cover is closed with the threaded portion.

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