JPH0545143Y2 - - Google Patents

Description

[Detailed explanation of the idea] Industrial applications The present invention relates to a cutting blade for a lawn mower.

2. Description of the Related Art A cutting blade for a lawn mower is known in which an endless saw chain is attached around a circular blade, and the blade is rotationally driven to cut grass with the saw chain. Such a cutting blade is disclosed, for example, in Japanese Patent Laid-Open No. 109601/1983. Conventional cutting blades of this type have a circular blade, and the entire endless saw chain provided around the blade is arranged on an equal radius circle from the center of the blade, and when the circular blade is rotated during mowing, The entire saw chain is constructed so that it cuts the grass by successively hitting the grass, and because the saw chain is fixed to the blade so that it does not shift, it is difficult to replace the saw chain, and it is difficult to replace the saw chain during work. The disadvantages are that the impact received when hitting a hard object is large, and the useful life of the cutting blade is relatively short.

Problems to be Solved by the Invention Therefore, an object of the present invention is to eliminate the drawbacks of the conventional techniques as described above, and to provide a mowing blade for a lawn mower that is simple in structure and convenient to use.

Means for Solving the Problems That is, according to the present invention, there is provided a cutting blade for a lawn mower in which an endless saw chain is slidably guided and supported over the entire circumference of a rotatably driven plate-shaped blade. It is characterized in that the blade is formed in a non-circular shape. Preferably, the blade is formed in a non-circular shape such as an equilateral triangle or a regular square, and the top of the periphery of the blade is rounded in the circumferential direction.

Function: Therefore, normally only a portion of the endless saw chain is involved in mowing work, and the saw chain moderately shifts its position relative to the blade due to the impact received during work, absorbing the impact and renewing the blade. Can be done.

Embodiments Next, the present invention will be explained based on embodiments shown in the drawings.

First, the cutting blade of the embodiment shown in FIG. 1 has a blade 1 made of a thin steel plate formed in an equilateral triangular non-circular shape as a whole, and three peaks 3 formed around the blade 2 will be described later. The endless saw chain 4, which is the same as that used in the chains used in the present invention, is rounded in the circumferential direction with a small radius so that it can slide when subjected to an impact exceeding a predetermined value. The blade 1 has a center hole 5 at its center, and is attached to a rotary shaft (not shown) of a mower through the center hole 5 so as to be rotationally driven. Furthermore,
The blade 1 has guide members 6 and 7 attached to both sides thereof extending in a similar shape along the entire periphery 2, and the guide members 6 and 7 are partially shaped as shown in FIG. Surroundings 2 of the blade 1
A circumferential groove 8 protrudes radially outward from and between them.
is formed. A base 9 of the endless saw chain 4 (a tongue of a drive link in the case of a chainsaw) is arranged in this circumferential groove 8, and the base 9 of the saw chain 4 is connected to the blade 1 by the guide members 6 and 7. They are guided in a relatively slidable and non-removable manner in the circumferential direction. As described above, each top portion 3 of the blade 1 is rounded with a small curvature in the circumferential direction, so that a predetermined resistance is provided to the sliding of the endless saw chain relative to the blade 1 in the circumferential direction. .

Note that the blades 1 of the guide members 6 and 7
As for the fixing method, any suitable method can be used as required, such as cutper brazing, screw fixing, riveting, etc.

When the cutting blade according to the present invention configured in this way is attached to the rotary shaft of the mowing machine and rotationally driven during grass cutting work, the three tops 3 of the blade 1 are mainly
Only the part of the saw chain 4 located at 1 touches the grass and performs the mowing work, and the other parts of the saw chain 4 do not substantially participate in the mowing work. In this way, only one part of the saw chain 4 is mainly involved in mowing work, but since the cutting blades are normally rotated at a relatively high speed, the work is carried out smoothly without any problems, and other parts of the saw chain 4 are not damaged. It is maintained in substantially unused condition without being subjected to wear or tear. When the part of the saw chain 4 located at each top 3 of the blade 1 receives a strong impact of more than a predetermined value, the saw chain 4 slides along the periphery 2 of the blade 1 to absorb the impact, and removes the unused part of the saw chain 4. The part is located on the top 3 of the blade 1. Due to the equilateral triangular shape of the blade 1, this is done simultaneously for all the tops 3.

Next, in the cutting blade of the embodiment shown in FIG. 3, the blade 1 is formed as a whole in a regular square non-circular shape, and around the blade 1 there are four rounded tops 3 with small curvature in the circumferential direction. The cutting blade is different from the cutting blade shown in FIG. 1 in that it has the following features, but other parts are constructed and operate in the same manner as the cutting blade shown in FIG. Therefore, the cutting blade shown in FIG. 3 performs grass cutting work at the endless saw chain 4 located at the four tops 3.

Furthermore, the cutting blade of the embodiment shown in FIG. 4 is formed in a non-circular elliptical shape, and is constructed so as to cut grass in the portion of the endless saw chain 4 located on the periphery in the elongated direction of the blade 1.

Although the embodiment shown in the drawings has been described above, in the present invention, the blade 1 can have a non-circular shape other than that described above. However, from the viewpoint of manufacturing and actual use, it is preferable that the blade 1 has a non-circular shape of an equilateral triangle or a regular square as shown in FIGS. 1 and 3.

Effects of the invention With the structure of the invention explained above, the invention has the following effects:
Normally, only a portion of the endless saw chain is involved in mowing work, and the impact received during work causes the saw chain to shift its position appropriately relative to the blade, allowing the blade to be renewed while absorbing the impact.
The useful life of the saw chain can be greatly extended, and the cutting blade can be easily and inexpensively manufactured.

[Brief explanation of the drawing]

1 is a plan view of a blade of a cutting blade showing an embodiment of the present invention; FIG. 2 is a partial sectional view showing a state in which an endless saw chain is attached around the blade of the cutting blade of FIG. 1; The figure is a plan view of a blade of a cutting blade showing another embodiment of the present invention, and FIG. 4 is a plan view of a blade of a cutting blade showing still another embodiment of the invention. 1...blade, 2...around the blade, 3...
...Top of the blade, 4...Endless saw chain.

Claims (1)

[Claims for Utility Model Registration] (1) A cutting blade for a lawn mower in which an endless saw chain 4 is slidably guided and supported over the entire periphery 2 of a rotatably driven plate-shaped blade 1, A cutting blade for a lawn mower, characterized in that the blade is formed into a non-circular shape. (2) Utility model registration claim No. 1, characterized in that the blade is formed in a non-circular shape of an equilateral triangle or a regular square, and the apex 3 of the periphery of the blade is rounded in the circumferential direction. A cutting blade for a lawn mower according to item 1.