JPH0730006U - Blade for mower - Google Patents

Abstract

(57) [Abstract] [Purpose] We improved the impact resistance of blades for mowers,
Moreover, it has excellent mowing performance. [Structure] An impact receiving part is provided on the outer edge of each large tooth on the outer circumference of the blade to guide weeds etc. to the side edge cutting edge, and the cutting edge is linear in the radial direction, or the inner edge is delayed in the rotation direction. The shape is straight or curved located on the side to improve the mowing efficiency. Further, the impact receiving portion is provided in front of the cutting blade so that stone blocks and the like are flipped outward, and the large tooth portion has a width sufficient to obtain impact resistance.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a blade for a mower, and more particularly to a blade designed to prevent damage caused by a lump of stone or concrete.

[0002]

[Prior art]

 When cutting grass with a mower, a blade with multiple cutting blades is used, but a blade for a hard mower has a serrated outer edge of a substantially disk-shaped blade, and the side edge of each saw tooth on the advance side in the rotation direction. It is common to form a cutting edge on.

However, in order to mow weeds and the like by a plurality of cutting blades rotating at high speed along a circumferential trajectory, each cutting blade is extended to the outermost edge of the plate, and the cutting edge outer edge side is used. The structure is designed to mow, but if there is stone or concrete on the ground to be mowed, the cutting edge will collide violently with it and some or all of the cutting edge will be chipped and easily scattered, which is terrible. In some cases, the saw teeth themselves were chipped and the life was very short.

Therefore, in conventional blades for mowers, a hard special steel cutting edge tip is fixed to the side edge of each saw tooth on the leading side in the rotation direction by brazing to improve the impact resistance of the cutting edge. Is being done.

[0005]

[Problems to be solved by the device]

 However, in the actual mowing work, the engine speed usually reaches 2000 to 3000 rpm, and the maximum is 4000 rpm, so the impact force exerted on each cutting edge tip and saw blade due to collision with stones is very large. It was virtually impossible to manufacture a cutting edge tip or saw blade that could withstand the above-mentioned problems, and the problems of chipping of the cutting edge and lack of saw blades were still unsolved.

In view of the above problems, it is an object of the present invention to provide a blade for a mower having excellent impact resistance with respect to stone blocks and the like.

[0007]

[Means for Solving the Problems]

 Therefore, a blade for a mower according to the present invention is attached to a holder rotary shaft at the tip of a rod of a mower, and a blade that is rotated at a high speed by an engine at the rear end of the mower to mow the blade can be attached to the rotary shaft. On the outer circumference of the base, a plurality of large tooth portions are provided to extend outward in the radial direction at equal angular intervals in the circumferential direction, and each large tooth portion has a width sufficient to obtain impact resistance in the circumferential direction. None, and a cutting edge is provided on the side edge on the leading side in the rotation direction of each of the plurality of large teeth, and the blade shape of each cutting edge is either a straight line extending substantially in the radial direction of the mounting base or the inner end side of which has a radial direction. A straight line or a curved line is located on the lag side in the rotation direction with respect to the straight line, while the impact receiving part is provided on the outer edge of the large tooth portion so as to project to the advance side in the rotation direction from the cutting edge. It is characterized by

Since the large tooth portion secures impact resistance by the width in the circumferential direction, the number thereof is optimally 3 or 4 in consideration of the width of the tooth portion. This is because with two teeth, the vibration during mowing work is severe, and with many teeth weeds cannot move inside the cutting blade and cannot be cut. The shape of the large tooth portion is not particularly limited and may be a quadrangular shape, but in order to secure sufficient impact resistance, it is preferable to have a shape in which arcuate shapes are combined as shown in the following examples.

[0009] In order to ensure high mowing performance, the cutting edge is designed to move weeds and the like inward along the cutting edge during a short time during high-speed rotation. It is preferable to make a straight line extending substantially in the direction, or a straight line or a curved line whose inner end side is located on the delay side in the rotation direction with respect to the straight line in the radial direction. It has an arc shape that is recessed to the side, and this cutting edge is formed by grinding and polishing the side edge of the large tooth portion, and if the large tooth portion wears or the cutting edge wears due to long-term use, it can be polished and repaired for long-term use. .

The impact receiving portion may be formed by bending the outer edge of the large tooth portion, or a separate impact receiving portion may be manufactured and this may be brazed or welded to the outer edge of the large tooth portion. You may fix it. The shape of the impact receiving portion is not particularly limited, but it is preferably a shape extending in the circumferential direction in order to reliably receive a large impact.

[0011]

[Action and effect of the device]

 When the rotary shaft is driven by the engine at the rear end of the rod, the large tooth portion of the blade is rotated at high speed along a circular locus determined by its radius, and each cutting edge causes weeds, reeds, bamboo grass, plows, and small diameter standing trees. To be cut.

At that time, since the impact receiving portion is provided so as to project to the advance side in the rotation direction of the cutting edge, if there is a lump of stone or concrete between weeds or the like, these collide with the impact receiving portion that rotates at a high speed. Then, it is blown out to the outside, almost never collides with the cutting edge, it is possible to reliably prevent the cutting edge from chipping, and the large tooth has a width sufficient to withstand impact, so the large tooth is Without being chipped or deformed by impact, the impact resistance of the blade can be improved and the life can be greatly improved.

Further, since the impact receiving portion projects toward the leading side in the rotation direction of the cutting blade, weeds and the like in front of the impact receiving portion are fed to the cutting blade side as the blade rotates at high speed, and each cutting blade is Since it has a straight line extending in the radial direction or a shape in which its inner end side is located on the lag side, weeds and the like move to the inner end side of the cutting blade along the cutting edge, and weeds and the like are reliably cut.

[0014]

【Example】

 Hereinafter, the present invention will be described in detail based on specific examples shown in the accompanying drawings. 1 to 3 show a blade for a mower according to an embodiment of the present invention. 2 and 3, the blade 1 is manufactured by using a steel plate having a thickness of about 1.8 mm, for example, a spring steel plate, and a central portion of the blade 1 serves as a mounting base 10 having a mounting hole 100.

On the outer peripheral edge of the mounting base 10, three large tooth portions 11 are integrally formed so as to project outward in the radial direction at intervals of 120 ° in the circumferential direction, and the three large tooth portions 11 are formed as a whole. And three equal circular arcs are combined so that they become higher toward the blade rotation direction leading side toward the outer side, and form an out-of-plane shape that is continuous with the next circular arc through a step. The width is such that sufficient impact resistance can be obtained in any direction.

A cutting edge 12 is formed by cutting and grinding on a side edge of each of the large-sized tooth portions 11 on the leading side in the rotation direction, and the cutting edge of the cutting edge 12 is recessed on the lag side in the rotation direction with respect to the straight line a in the radial direction. It has a circular arc shape.

Further, the outer edge of each of the large-sized tooth portions 11 is bent upward by a predetermined dimension, and the bent portion serves as an impact receiving portion 13, and the impact receiving portion 13 is more than the cutting edge 12. The shape is such that it projects from the leading side in the rotation direction and extends to the lagging side in the circumferential direction.

When the blade 1 is attached to the mower 2, as shown in FIG. 2, the holder rotating shaft 22 at the tip of the rod 20 is sequentially inserted into the attachment hole 100 of the blade 1 and the attachment hole 230 of the attachment plate 23, and the reverse rotation is performed. The blade 1 is fixed to the rotary shaft 22 by screwing the screw nut 24 onto the rotary shaft 22.

Here, the structure of the mower 2 will be briefly described. As shown in FIG. 1, a holder 21 is provided at the tip of the rod 20 and an engine 25 is mounted at the rear end of the rod 20. The drive shaft of the engine 25 and the rotary shaft 22 of the holder 21 are connected by a transmission mechanism in the rod 20, and the holder rotary shaft 22 is driven by the engine 25. Further, a hand-held handle 26 having a substantially U-shape is provided slightly behind the middle portion of the rod 20, and a shoulder strap 26 is provided behind it, and the shoulder strap 27 is hung on the shoulder, and the handle 26 is held by both hands. You can operate the mower 2 by holding.

Next, the function and effect will be described. When the engine 25 is driven, the blade 1 is rotated at high speed together with the rotating shaft 22, and the three cutting edges 12 of the blade 1 mow the blade.

Usually, in the mowing work, the blade 1 rotating at a high speed is reciprocated leftward and rightward, and is gradually advanced. However, since the impact receiving portion 13 projects forward from the cutting blade 12, it is Due to the above blade operation and high speed rotation, the weeds 4 in front of the impact receiving portion 13 are pushed toward the inner cutting edge 12 side as shown by the arrow A in FIG. 3, and further due to the arc shape of the cutting edge. As a result of moving inwardly along the cutting edge and efficiently contacting the cutting edge with the weeds 4, the weeds 4 are reliably cut.

According to the trial manufactures and experiments by the present inventors, the weeds 4 could be lightly and completely mowed, but further, reeds, bamboo grass, plows, and standing trees with a diameter of 2 cm or less can be reasonably mowed. I was able to. Therefore, in the past, a blade for exclusive use was also required for cutting down forests and felling shrubs. However, using blade 1 of this example, trees standing with a diameter of 2 cm or more are felled with a hatchet while leaving the rest. It was very useful because it could be mowed with the mower 2.

Further, if there is a stone block 3 within the operating range of the blade 1 during the mowing work, it may hit the cutting blade 12 rotating at high speed and the cutting blade 12 may be chipped. As shown by the arrow B, the stone block 3 always collides with the high-speed rotating impact receiving portion 13 before hitting the cutting edge 12 and is repelled to the outside by the high-speed rotational force. The collision does not occur so much, and the cutting edge 12 can be reliably prevented from being chipped.

Moreover, in the blade 1 of this example, since the large-sized tooth portion 11 has a wide width in the circumferential direction, the large-sized tooth portion 11 is not chipped or deformed by impact.

As a result, the impact resistance of the blade 1 can be improved and the life can be greatly improved. According to the prototypes and experiments conducted by the present inventors, the conventional blade for a mower causes chipping of the cutting edge immediately after the start of the work even when careful operation is performed when mowing in a place with many stone blocks. Moreover, since it occurs with many cutting edges, it became impossible to mow the grass in about 1 to 2 hours, but with the blade 1 of this example, even if the mowing work is carried out all day long, the cutting edges will be chipped. Was not seen at all, and it was confirmed that the life was greatly extended.

[Submission date] December 24, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

In order to ensure high mowing performance, the cutting edge moves the weeds and the like inward along the cutting edge during a short time during high-speed rotation. A straight line extending substantially in the radial direction or a straight line or a curved line whose inner end side is located on the delay side in the rotation direction with respect to the straight line in the radial direction is preferable. It has an arc shape that is recessed to the side, and this cutting edge is formed by grinding and polishing the side edge of the large tooth portion.If the large tooth portion wears or the cutting edge wears due to long-term use, it can be polished and repaired for long-term use. it can.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a mower to which a blade according to an embodiment of the present invention is applied.

FIG. 2 is an exploded perspective view for explaining a method of attaching the blade.

FIG. 3 is a plan view showing the blade.

[Explanation of symbols]

 1 Blade 10 Mounting Base 11 Large Tooth 12 Cutting Edge 13 Impact Receptor 2 Mower 20 Rod 21 Holder 22 Rotating Shaft 25 Engine 3 Stone Clump 4 Weed

Claims (2)

[Scope of utility model registration request] 1. A blade which is attached to a holder rotating shaft at the tip of a rod of a mower and is used for mowing by being rotated at a high speed by an engine on the rear end side of the rod. The large tooth portions are provided so as to extend outward in the radial direction at equal angular intervals in the circumferential direction, and each large tooth portion has a width sufficient to obtain impact resistance in the circumferential direction. A cutting edge is provided on the side edge on the advance side in the rotation direction of the portion, and the cutting edge of each of the cutting edges is a straight line extending substantially in the radial direction of the mounting base, or the inner end side thereof is on the delay side in the rotation direction with respect to the radial direction. The blade for a mower is characterized in that the impact receiving portion is provided on the outer end edge of the large-sized tooth portion so as to project in the rotational direction advance side with respect to the cutting edge while being linear or curved. . 2. The blade for a mower according to claim 1, wherein the cutting edge of each of the upper cutting blades has an arcuate shape which is recessed in the rotational direction delay side with respect to the radial direction.