JPH0223130B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rotary blade for a brush cutter, particularly a rotary blade with an exchangeable blade body, and is used for mowing lawns, weeds, etc.

(Prior Art and its Problems) Various types of rotary blades for brush cutters have been proposed. One such example is the rotary blade described in Japanese Patent Publication No. 60-4689, which was previously proposed by the inventor of the present invention. This is a disc-shaped support member and a plurality of blades protruding approximately radially from the periphery of the disc-shaped support member, which are integrally molded from an elastic polymer material. This rotary blade has the great advantage of being sharp because it has a large number of blades, and being safe and less likely to be damaged even if it comes into contact with an obstacle. However, by using a rotary blade, although the supporting member hardly wears out, the blade body collides with grass, weeds, and other obstacles at a high circumferential speed, causing rapid wear, which shortens the service life of the rotary blade as a whole. I was getting used to it. Further, before the blade ends its life due to normal wear, one of the blades may be damaged due to collision with an obstacle or the like. In such a case, the rotary blade must be balanced by cutting a blade in a symmetrical position to the damaged blade in the same shape, or else it becomes unusable and must be discarded.

As described above, the life of the entire rotary blade is limited by the life of the blade, damage, etc., and as a result, the number of rotary blades used has increased, leading to an increase in running costs.

Further, depending on the condition of the lawn or grass, it may be preferable to reduce the number of blades of the rotary blade and perform mowing work. However, in the above-mentioned conventional rotary blade, since the blade body is integrated with the support member, the number of blade bodies cannot be reduced, and if one blade body is removed, it cannot be restored.

In order to solve this problem, the rotary blade is divided into a plurality of blade bodies and a disc-shaped support member, and a plurality of mounting pieces having insertion holes are provided around the support member. A rotary blade for brush cutters has been proposed in which the blade is inserted into the
169141, Utility Model Publication No. 144396).

However, in the conventional rotary blade for a brush cutter mentioned above, the former has a blade extending straight in the radial direction and an edge is provided only on one side of the blade. It is not possible to use different types of blades depending on the type of grass or plants to be cut, especially their hardness, and the blade must be replaced due to wear of a single edge.

In addition, although the latter type of rotary blade for brush cutters has edges on both sides of the blade, each edge has the same angle with respect to the radial line, so the grass and plants to be cut are It was not possible to use the same blade depending on the type.

In view of the above-mentioned problems, the present invention aims to provide a rotary blade for a brush cutter in which the blade body is easily replaceable and the same blade body can be used depending on the type of grass or plants to be cut. The purpose is

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a brush cutter with a plurality of blade bodies protruding approximately radially from the periphery of a flexible disc-shaped support member. The rotary blade has a plurality of mounting pieces having insertion holes penetrating in the radial direction provided near the periphery of the support member at equal intervals in the circumferential direction, and the blade body has a base portion. and a blade portion narrower than the base portion, the blade portion including an insertion portion that is inserted into and supported by the insertion hole, and a cutting edge portion that is inclined at an angle with respect to the insertion portion and has edges on both sides. It is characterized by the following.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

In FIGS. 1 to 8, a rotary blade 1 includes a disk-shaped support member 2 made of an elastic polymer material, and a plurality of blade bodies 3 made of an elastic polymer material and protruding radially around the support member 2. It is equipped with... As shown in particular in FIGS. 7 and 8, the blade body 3 consists of a base 4 for attachment, and a blade 5 that is continuous with the base 4 and has a narrower width than the base 4. The portion 5 includes an insertion portion 5a coaxial with the base 4, and a coaxial insertion portion 5a with the base 4.
and a cutting edge portion 5b having edges 6, 6 on both sides, which are inclined at an angle with respect to the insertion portion 5a.

On one surface 2a of the support member 2, the support member 2
Mounting pieces 7 having a substantially U-shaped cross section and having elongated insertion holes 8 penetrating in the radial direction are provided at equal intervals in the circumferential direction. is inserted radially outward from the center of the support member 2, and the insertion portion 5a of the blade 3 is inserted into the insertion hole 8.
The stepped portion 4a comes into contact with both inner end surfaces 7c, 7c of the mounting piece 7 when it is located inside. The support member 2 has an end surface 4b of the base 4 of the blade 3.
A locking piece 9 that prevents the blade 3 from coming off toward the center of the support member 2 is provided at a position where it comes into contact with the support member 2 . The locking piece 9 has a substantially L-shaped cross section, consisting of a locking base 10 that abuts the end surface 4b and a locking cover 11 that covers the upper surface near the end surface 4b, and has side walls on a portion of both sides. Sections 12, 12 are provided. Also, both end surfaces 4c, 4c of the base 4 of the blade 3
Side wall portions 13, 13 for covering the gap between the surface 2a of the support member 2 and the base portion 4 are provided continuously along the aforementioned mounting piece 7. A narrow groove 7b having a depth of approximately half the thickness of the upper side 7a of the mounting piece 7 is provided, and serves as a guide for determining the degree of wear on the mounting piece 7.

The support member 2 is provided with buffer holes 14 and 15 near where the blade 3 is attached, and a mounting hole 16 in the center. These buffer holes 14 and 15 are intended to increase the flexibility of this part, and when the blade body 3 collides with a hard obstacle, this part bends together with the flexibility of the material, and the blade body 3, the mounting piece 7, etc. are prevented from being damaged. Furthermore, the mounting piece 7 tends to extend due to the centrifugal force caused by the rotation of the rotary blade 1;
These buffer holes 14 and 15 encourage the expansion to some extent, thereby causing the insertion hole 8 to contract, and the insertion portion 5a of the blade body 3 to be gripped by the mounting piece 7. . Therefore, the insertion hole 8 is made slightly larger than the blade portion 5 so that the blade body 3 can be easily attached and detached, and when the rotary blade 1 is used, the blade body 3 is rotated. It is possible to securely hold it by the attachment piece 7. In this case, the hardness of the blade 3 is made larger than that of the support member 2, and the insertion portion 5a
It is preferable to keep it from stretching itself too much. However, if these buffer holes 14 and 15 are too large or too close to the outer periphery of the support member 2 or the mounting piece 7, the strength of that part will be weakened, making it easy to damage or causing the blade to become slightly damaged. Since it will bend due to impact and lose its sharpness, be sure to install it at an appropriate size and location. These buffer holes 14,1
5, the cooling effect also has the added benefit of weight and material savings. An edge 14a is provided at the inner edge of the buffer hole 14.

Particularly with reference to FIG. 4, a disk-shaped core 17 is embedded in the center of the support member 2 in order to limit radial expansion caused by centrifugal force due to rotation. This core 17 is made of a steel plate or the like, and is integrally embedded, for example, when the support member 2 is injection molded. 18 is a pin hole for positioning at that time. Further, reference numeral 19 denotes a reinforcing annular rib provided on the support member 2.

The support member 2 and blade body 3 of the rotary blade 1 described above are
Each material is injection molded using a thermoplastic polymer material, such as polyurethane elastomer and polyester elastomer, which have excellent abrasion resistance, bending resistance, and tear resistance, as well as natural rubber and synthetic rubber. , or those mixed with carbon black or various fibers are used.

The rotary blade 1 constructed as described above is used by being attached to a brush cutter using the attachment hole 16 so that the surface shown in FIG. 1 is the top surface, and being rotated to the left. The blade body 3, the mounting piece 7 for attaching the blade body 3, the locking piece 9, the side wall part 13, and the buffer holes 14 and 15 are provided at equal intervals in the circumferential direction of the rotary blade 1, so that the balance is maintained. has good vibration and does not generate abnormal vibrations. Since the blade body 3 is an elastic body and the support member 2 is provided with buffer holes 14 and 15, even if it collides with an obstacle, it will bend elastically and will not be damaged and will not cause excessive recoil. It is safe because there is no
If the blade 3 becomes worn out or damaged by any chance, you can easily replace only that blade 3. Therefore, if you keep the blade 3 as a consumable item, it will last for a long time. can be used to reduce running costs. To replace the blade 3, turn the locking cover 11 of the locking piece 9 backward by hand or with a screwdriver, and insert the blade 3 into the insertion hole 8.
After pulling it out, a new blade 3 can be inserted. Since these are made of elastic material, they can be easily attached and detached. Moreover, the locking base 1 of the locking piece 9
0 prevents the blade 3 from coming off toward the center, the side walls 12 and 13 prevent the blade 3 from shifting in the circumferential direction, and the locking cover 11 prevents the blade 3 from slipping off toward the center. Since the blade body 3 is held down so that it does not float up, there is no risk that the blade body 3 will fall off unexpectedly, so it is safe. Because the side walls 12 and 13 are present, the support member 2
This prevents dirt, grass, etc. from entering the gap between the surface 2a and the blade 3. When the buffer holes 14 and 15 are provided at appropriate positions, the insertion hole 8 contracts due to the radial expansion of the mounting piece 7 due to centrifugal force.
The blade body 3 is clamped and becomes even more stable.

If the blade 3 is damaged and there is no spare blade to replace it, a blade in a symmetrical position to that blade,
Alternatively, by removing two blades that are equally spaced from each other, the number of blades 3 will be reduced, but the number of rotary blades 1 will be reduced.
can be used without disturbing the balance. Furthermore, even if the blade 3 is not damaged, the blade 3 at the same position may be removed and used depending on the condition of the grass or grass. Blade tip portion 5b of blade body 3
has an inclination angle with respect to the radial direction line, and has edges 6, 6 on both sides of the cutting edge portion 5b,
By turning the blade body 3 upside down and attaching it to the attachment piece 7, the angle at which the edge 6 cuts into the grass, plants, etc. changes, and the sharpness changes. Therefore, for example, when mowing grass or plants of normal hardness or relatively hardness, the blade should be cut so that the angle between the edge 6 on the side to be used and the tangent line is an obtuse angle, as shown in Figure 1. body 3
When cutting relatively soft vegetation with the
Turn the blade body 3 over and attach it so that the above-mentioned angle becomes an acute angle. In this way, the same blade 3 can be used depending on the type of grass or plants to be cut. By using the rotary blade 1, the mounting piece 7
If the narrow groove 7b provided in the support member 2 becomes shallow or disappears, the life span of the support member 2 can be determined from this, and the support member 2 may be replaced.

In the above embodiment, six blade bodies 3 are provided, but the number may be four, five, eight, etc. By providing the edges 6 with serrations, it is possible to adapt to various types of grass and plants. The buffer holes 14 and 15 may be circular, oval, or square, or may be bottomed recesses that do not penetrate through them. Further, these may be omitted as appropriate depending on the size and material of the rotary blade 1. It is also possible for the locking piece 9 and the side wall 13 to have other shapes or to be omitted. There may be two or three narrow grooves 7b, and these may be formed into protrusions, or may be omitted. Although the rotary blade 1 in the above embodiment is made of an elastic polymer, it can also be made of other flexible materials.

(Effects of the Invention) According to the present invention, the support member and the blade body are separate bodies, and the blade body can be easily attached to and removed from the support member, so that the blade body can be easily replaced.
Moreover, since the cutting edge of the blade has an inclination angle with respect to the insertion part and has edges on both sides of the cutting edge, by turning the blade upside down and attaching it, you can easily cut the edge against grass, plants, etc. Since the cutting angle changes and the sharpness changes, the same blade can be used depending on the type of grass or vegetation to be cut.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is a plan view of the rotary blade, FIG. 2 is an enlarged view of the main part of FIG. 1, FIG. 3 is a view taken in the direction of the arrow in FIG. 2, FIG. 5 is a cross-sectional view taken along the line - in FIG. 2, FIG. 6 is a sectional view taken along the line - in FIG. FIG. 8 is a view taken along the arrows in FIG. 1... Rotary blade (rotary blade for brush cutter), 2... Support member,
3...Blade body, 4...Base, 5...Blade portion, 5a...Insertion part, 6...Edge, 7...Mounting piece, 7b...Slim groove, 8
...insertion hole, 9...locking piece, 10...locking base, 11
... Locking cover part, 12, 13... Side wall part, 14, 15...
buffer hole.

Claims (1)

[Scope of Claims] 1. A rotary blade 1 for a brush cutter comprising a plurality of blade bodies 3 protruding approximately radially from the periphery of a flexible disc-shaped support member 2, comprising: Nearby, a plurality of mounting pieces 7 having insertion holes 8 penetrating in the radial direction are provided at equal intervals in the circumferential direction, and the blade body 3 has a base 4 and a width smaller than the base 4. It consists of a narrow blade part 5, and the blade part 5 has an insertion part 5a that is inserted into the insertion hole 8 and is supported, and has edges 6, 6 on both sides that are inclined at an angle with respect to the insertion part 5a. A rotary blade for a brush cutter, characterized by comprising a cutting edge portion 5b.