JPH0321Y2 - - 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. 4689/1989, 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.

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
No. 169141).

However, the blade body and mounting part are subject to the radial centrifugal force generated by the rotation of the rotary brush cutter blade, and the force generated by the blade body colliding with plants, stones, the ground, and other obstacles. Destructive force is a complex combination of tangential reaction force and tangential reaction force.

In the above-mentioned conventional rotary blade for a brush cutter, the strength of attaching the blade to the support member is low, so these deform and the posture of the blade with respect to the support member collapses, resulting in poor cutting of the rotary blade for the brush cutter. In addition, the blade falls off from the support member, and furthermore, the blade and the attachment piece break and scatter, resulting in safety problems and shortened service life.

In view of the above-mentioned problems, the present invention aims to provide a rotary blade for a brush cutter whose blade body is easily replaceable, whose blade body is securely held on a support member, and which is safe and has a long life. .

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a brush cutter with a plurality of blades protruding approximately radially from the periphery of a flexible disk-shaped support member. The blade body is a rotary blade, and the blade body consists of a base and a blade part continuous to the base, step parts wider than the blade part are provided on both sides of the base part, and each step part has a step part wider than the blade part. ,
A locking projection protruding in the thickness direction of the blade body is provided near the periphery of the support member, and the locking protrusion is formed of an inclined part and an upper side part and penetrates in the radial direction for inserting the blade body. A plurality of attachment pieces having insertion holes and a side wall portion surrounding the peripheral end surface of the base of the blade are provided, and each of the inclined portions is provided with a recess into which at least a portion of the step portion fits, The support member is characterized in that a locking hole into which the locking protrusion fits is provided at a position corresponding to the recess.

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

In FIGS. 1 to 8, the rotary blade 1 has a relatively flexible disc-shaped support member 2 made of an elastic polymer, and a support member 2 made of an elastic polymer that is harder than the support member 2. It is provided with a plurality of blade bodies 3 that protrude radially. 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 part 5 includes an insertion part 5a coaxial with the base 4, and a base 4 and the insertion part 5a.
and a cutting edge portion 5b having edges 6, 6 on both sides thereof. Two locking protrusions 4a, 4a are integrally provided on the lower surface of the base 4.

On one surface 2a of the support member 2, the support member 2
A mounting piece 7 having an elongated insertion hole 8 penetrating in the radial direction, and locking holes 9, 9 into which the locking protrusion 4a described above is inserted are provided at three locations at equal intervals in the circumferential direction. The above-mentioned blade 3 is inserted into the insertion hole 8 from the center of the support member 2 radially outward, and with the insertion portion 5a of the blade 3 positioned in the insertion hole 8. , the stepped portion 4b is in contact with the inner wall surface of the recesses 7a, 7a provided in the inclined portion 7b of the mounting piece 7, and the locking protrusion 4a is fitted into the locking hole 9. The support member 2 includes a support member 2 that surrounds the peripheral end surface 4c of the base 4 of the blade 3.
A side wall portion 10 for covering the gap between the surface 2a of the support member 2 and the base portion 4 is provided continuously to the aforementioned mounting piece 7. The side wall portion 10 has a height that is approximately the same as the thickness of the base portion 4 of the blade body 3 on both sides, and a center portion that is slightly lower than this, and this is continuous with a smooth curved surface. Further, both this side wall portion 10 and the above-mentioned mounting piece 7 have an inclined portion 10 that is smoothly inclined toward the surface 2a of the support member 2.
a, 10a, 10b, 7b, and 7b.
A recessed hole 11 having a depth of about half the thickness of the upper side 7c 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 at equal intervals in the circumferential direction. These buffer holes 14 are provided to increase the flexibility of this part, and when the blade 3 collides with a hard obstacle, this part of the support member 2 bends due to the flexibility of the material. This prevents the blade 3, mounting piece 7, etc. from being damaged. Furthermore, the attachment piece 7 tends to expand due to the centrifugal force caused by the rotation of the rotary blade 1, but the buffer hole 14
This facilitates its elongation 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 attachment 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. These buffer holes 14 also have the additional benefit of cooling and 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 configured 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 side wall part 10, and the buffer hole 14 are each provided at equal intervals in the circumferential direction of the rotary blade 1, so they are well balanced and do not generate abnormal vibrations. I won't let you. Since the blade body 3 is an elastic body and the support member 2 is provided with a buffer hole 14, even if it collides with an obstacle, it will bend elastically and will not be damaged, and no excessive recoil will occur. It's safe. 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. When replacing the blade 3, it is sufficient to bend the support member 2 near the side wall 10, pull the base 4 of the blade 3 to remove it from the insertion hole 8, and then insert a new blade 3. Since these are made of elastic material, they can be easily attached and detached. Moreover, since the locking protrusion 4a fits into the locking hole 9, and thereby the blade body 3 is locked to the support member 2, a load force is applied to the blade body 3 when the rotary blade 1 is used. Even if the blade body 3
It is safe as there is no risk of it falling off unexpectedly. The presence of the side wall portion 10 prevents dirt, grass, etc. from entering the gap between the surface 2a of the support member 2 and the blade body 3. Since the inclined portions 7b, 10a, and 10b are provided, resistance during use is reduced, thereby reducing damage and wear of the support member 2, reducing impact and wasted rotational power during use, Work efficiency improves. If the recessed hole 11 provided in the mounting piece 7 becomes shallow or disappears due to the use of the rotary blade 1, this will tell you the lifespan of the support member 2, so replace the support member 2. Bye.

In the above embodiment, it is possible to attach three blade bodies 3, but it is possible to attach four, six, and eight blade bodies.
It is also possible to use individual items. If the blade 3 is damaged and there is no spare blade to replace it, the blade can be replaced by removing blades located symmetrically to the damaged blade or blades equally spaced from each other. Although the number of bodies 3 is reduced, it is possible to use the rotary blade 1 without losing its balance. Further, even if the blade body 3 is not damaged, the blade body 3 may be removed and used in the same position as described above depending on the condition of the grass or grass. Furthermore, depending on the state of wear of the blade body 3 and the state of the grass, the rotary blade 1 may be turned over and the other edge 6 may be used for mowing. Moreover, the blade body 3 can also be used upside down. In that case, locking protrusions 4a are provided on both sides of the blade body 3,
Correspondingly, it is preferable to provide a recessed hole corresponding to the locking hole 9 in the upper side 7c of the mounting piece 7. Although the cutting edge portion 5b of the blade body 3 is inclined, it may be straight without being inclined. Also in this case,
The attachment piece 7 and the like may be provided to be inclined with respect to the radial direction, thereby making the cutting edge portion 5b inclined. The shape of the cutting edge portion 5b may be triangular, the tip may be arcuate, or various other shapes.The edge 6 may be a double taper type as in the embodiment, or may be a single taper type. The entire blade body 3 can have various shapes, such as having serrations.
The shape of the locking protrusion 4a and the locking hole 9 may be round or other shapes. The buffer hole 14 may be circular, oval, or square, or may be a bottomed recess that does not penetrate through these shapes. Further, these may be omitted as appropriate depending on the size and material of the rotary blade 1. Side wall part 10
It is also possible to have other shapes. There may be two or three recessed holes 11, and they may be formed into a narrow groove shape, or may be omitted. Although the rotary blade 1 of the above-described embodiment is made of an elastic polymer, it is also possible to manufacture them from other 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, the blade body is inserted into the insertion hole of the mounting piece,
The stepped portion and locking protrusion of the blade fit into the recess or locking hole, respectively, and the peripheral end surface of the base of the blade is surrounded by the side wall, so the blade can be firmly and securely attached to the support member. As a result, the posture of the blade relative to the support member is stabilized, and the blade does not accidentally fall off from the support member, resulting in safety and long life.

Further, when a recess is provided in the upper side, the degree of wear can be determined by the depth or presence or absence of the recess, and the support member can be replaced at an appropriate timing.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and 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, and 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. DESCRIPTION OF SYMBOLS 1... Rotary blade (rotary blade for brush cutter), 2... Support member, 3... Blade body, 4... Base, 4a... Locking protrusion, 5... Blade part, 5a... Insertion part, 5b...Blade tip portion, 6...Edge, 7...Mounting piece, 8...
Insertion hole, 9...locking hole.

Claims (1)

[Claims for Utility Model Registration] (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 disk-shaped support member 2, the blades comprising: The body 3 consists of a base 4 and a blade 5 continuous to the base 4, step portions 4b, 4b wider than the blade portion 5 are provided on both sides of the base 4, and each of the step portions 4b , 4b are provided with locking protrusions 4a, 4a that protrude in the thickness direction of the blade 3, and an inclined portion 7 is provided near the periphery of the support member 2.
b, 7b and the upper side 7c of the blade body 3.
radially penetrating insertion hole 8 for inserting the
a plurality of mounting pieces 7 having
A side wall portion 10 surrounding the peripheral end surface 4c of the base portion 4 is provided, each of the inclined portions 7b, 7b is provided with recesses 7a, 7a into which at least a portion of the step portions 4b, 4b fit, and the support member A rotary blade for a brush cutter, characterized in that locking holes 9, 9 into which the locking protrusions 4a, 4a fit are provided at positions corresponding to the recesses 7a, 7a. (2) The rotary blade for a brush cutter according to claim 1, wherein the upper side portion 7c is provided with a recessed portion 11 for indicating the degree of wear of the upper side portion 7c.