JP2007116924A - Grass-cutting blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grass-cutting blade whose sharpness can easily be improved by a general user without needing a special grinding device or a skilled grinding technique, when the sharpness of the used blade is lowered, and to provide a grass-cutting blade which can prevent deformation caused by kickback or the like, is hardly worn, and can smoothly perform cutting works. <P>SOLUTION: This grass-cutting blade is characterized in that many saw tooth units 4... are integrally formed from a steel plate equivalent to a disk-like steel plate substrate 6 on the outer periphery 6a of the substrate 6 at a prescribed pitch, and each saw tooth unit 4 sequentially comprises a notching depth-limiting projection 3, a dent portion 2 and a tooth portion 1 from the upstream of a rotation direction to the downstream. The tooth portions 1 of the many saw tooth units 4 are formed by alternately bending each tip half portion 11 in front and back reverse directions. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a grass cutting blade that is used by being attached to a brush cutter for cutting grass and twigs in forests, gardens, and fields.

Conventional grass cutting blades are known in which a large number of tooth portions are formed on the outer periphery of a disk-shaped base body, and a super steel tip blade is brazed to the tip of each tooth portion (see, for example, Patent Document 1). .
When the cutting edge of the grass cutting blade is worn out and the sharpness of the grass cutting blade is lowered, each tip blade is polished using a dedicated diamond tool.
JP 10-42653 A

  However, since a skilled technique is required to polish a super steel tip using a diamond tool, it is very difficult for a general user to polish using a diamond tool to improve the sharpness of a tip blade. Therefore, if the sharpness of the super steel tip is deteriorated after the mowing operation, a general user often discards the mowing blade without performing the polishing operation of the tip blade. Further, the sharpness of the super steel tip blade is slightly reduced immediately after the use of a new one, and has a feature that it continues for a long time in the state of the reduced sharpness. However, as described above, it is difficult for the user to grind the ultra-steel chip, and the mowing operation is performed using a slightly sharpened grass cutting blade, which is inconvenient.

Therefore, the present invention can easily improve the sharpness even if the general user does not have a specialized polishing apparatus or a skilled polishing technique when the sharpness has been lowered by use. The purpose is to provide a mowing blade.
It is another object of the present invention to provide a mowing blade that can prevent deformation due to kickback or the like and is less likely to wear and that can perform a mowing operation smoothly.

  In order to achieve the above-mentioned object, the grass cutting blade according to the present invention has a plurality of sawtooth units on the outer periphery of a disk-shaped steel plate base portion with a predetermined pitch and the same steel plate as the base portion. Each of the sawtooth units is formed integrally, and sequentially includes a cut depth limiting protrusion, a recess, and a tooth portion from the upstream to the downstream in the rotation direction.

Further, the tooth portions of a large number of the sawtooth units are formed such that the tip half portions are alternately bent in opposite directions.
Further, the tooth portions of a number of the sawtooth units have their base end halves alternately folded once with a gentle inclination angle of 5 ° to 40 ° in the reverse direction of the front and back sides, and the base end halves are radially outward. The tip half that is connected to the end is folded back in the opposite direction, and the tip half is provided in an orthogonal direction substantially orthogonal to the base portion, and substantially extends over the entire tip half and a part of the base half. An L-shaped cutting edge is formed.

Moreover, the rake angle of the front-end | tip blade edge of the said front-end | tip half part was set to 25 degrees-35 degrees in the said tooth part of each said sawtooth unit.
Alternatively, the rake angle of the substantially L-shaped cutting edge was set to 25 ° to 35 °.
Furthermore, the base part and the sawtooth unit are subjected to a parkerizing process after quenching.

The present invention has the following remarkable effects.
In the grass cutting blade according to the present invention, a large number of sawtooth units are integrally formed on the outer periphery of a disk-shaped steel plate base portion with a predetermined pitch and the same steel plate as the base portion. Therefore, it can be easily polished to increase the sharpness. Therefore, unlike a mowing blade having a tip attached to a tooth portion, it is not necessary to perform specialized polishing using a diamond tool, so that one mowing blade can be used in a state with good sharpness for a long period of time.
Each saw-tooth unit is provided integrally on the outer periphery of the disc-shaped base portion, and sequentially from the upstream to the downstream in the rotational direction, the cut depth limiting protrusion, the recess, and the tooth portion. Therefore, unlike a general chainsaw, the sawtooth unit during shaving is prevented from rattling and wavy, and can be trimmed in a stable state, so that efficient mowing is possible.
In addition, the tooth portions of a number of sawtooth units have their tip halves alternately bent in opposite directions, so that the material to be cut from the side and lower side of the sawtooth unit can be trimmed. Mowing is possible and work efficiency is very good. Further, kickback during use can be prevented.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments.
1 to 5 show an embodiment of a grass cutting blade according to the present invention. This grass cutting blade has a plurality of sawtooth units 4 with a predetermined pitch P on the outer periphery 6a of a disk-shaped steel plate base portion 6. And it is integrally formed with the same steel plate as the base 6. In other words, the grass cutting blade processes a single disk-shaped steel material, and forms a disk-shaped base portion 6 (within the circular range surrounded by a two-dot chain line in FIGS. 1 and 2) and an outer side of the two-dot chain line. A plurality of saw-tooth units 4 formed integrally with the outer periphery 6a of the base portion 6 are formed.
The base portion 6 is provided with a large number of small holes 17... So that the diameter of the small holes 17 gradually increases from the inner diameter side to the outer diameter side of the base portion 6. The L indicates the rotation center of the mowing blade.
The external dimensions of the grass cutting blade, that is, the distance between the tips of the saw blade units 4 and 4 facing each other on the line in the radial direction R is, for example, about 250 mm, and the number of the saw blade units 4. ~ 30 (preferably around 24). The predetermined pitch P of the sawtooth units 4... Is set wide and sharp.

  Next, each saw-tooth unit 4 is obtained by pressing a small protruding plate piece that protrudes outward (continuously) from the outer periphery 6 a of the base portion 6, from upstream to downstream in the rotational direction 18. The cutting depth limiting protrusion 3, the recess 2, and the tooth 1 are sequentially formed. That is, the intermediate portion in the outer peripheral direction of the small protruding plate piece is cut out in a curved shape, and the concave portion 2 of the sawtooth unit 4 is formed. In addition, the cut depth limiting protrusion 3 is formed in a curved shape so that a portion continuous with the front end (in the rotational direction 18) of the recess 2 has a protruding shape.

  And the tooth | gear part 1 ... of many saw-tooth units 4 has the front-end | tip half part 11 ... bend | folded alternately by the press process in the front and back reverse direction. Specifically, the tooth portions 1 of the plurality of sawtooth units 4... Have their base end half portions 13 alternately bent once in a reverse inclination direction with a gentle inclination angle .alpha. The tip half 11 connected to the radially outer end of the half 13 is folded back in the opposite direction, and the tip half 11 is provided in an orthogonal direction substantially orthogonal to the base body 6. Of the adjacent sawtooth units 4, 4, the tooth portion 1 of one unit 4 is continuously provided in a flat surface shape from the outer periphery 6 a of the base portion 6 when viewed from the front in the rotational direction 18 and has the inclination angle α. A proximal half 13 once bent in a downwardly inclined manner, and an upward distal half 11 continuously provided with a bent portion 10 on the distal end side of the proximal half 13. Is directed upward (see FIG. 3). Further, the tooth portion 1 of the other unit 4 is provided in a flat surface from the outer periphery 6 a of the base portion 6 and is bent once upwardly with the inclination angle α, and a base end half 13. The end half 13 has a downward tip half 11 connected to the tip of the end half 13 with a bent portion 10, and the tip half 11 faces downward (see FIG. 4). 3 and 4 show a part of the mowing blade attached to the brush cutter.

Further, in the tooth portion 1 of each sawtooth unit 4, the entire front side portion of the tip half portion 11 and a part of the front side portion of the base end half portion 13 (the front side refers to the front in the rotation direction 18). A substantially L-shaped cutting edge 15 is formed continuously. The base end of the substantially L-shaped cutting edge 15 is formed up to a substantially intermediate portion of the base end half 13.
And the rake angle (theta) of the front-end | tip blade edge | tip 12 of the front-end | tip half part 11 is set to 25 degrees-35 degrees. Preferably, it is 30 °.
Further, the rake angle θ of the substantially L-shaped cutting edge 15 is set to 25 ° to 35 °. If the angle is less than 25 ° and exceeds 35 °, the tooth part 1 is likely to cause a kickback during the cutting operation, or the material to be cut (grass, bushes, twigs, etc.) cannot be sharply cut off. There is a risk that mowing will not be performed smoothly.
The leading edge 12 is formed at the leading end of the substantially L-shaped cutting edge 15 and is a part of the substantially L-shaped cutting edge 15.

  The material of the grass cutting blade is, for example, an alloy tool steel such as SKS-5, and the base portion 6 and the sawtooth unit 4... Are processed into this material, and the whole is subjected to heat treatment by quenching. Parkerizing treatment is then applied to provide corrosion resistance (rust prevention).

Then, when the above-mentioned grass cutting blade of the present invention is attached to the brush cutter and the material to be cut is cut off, the sawtooth units 4 of the grass cutting blade cut off the side and lower materials to be cut. That is, a portion of the substantially L-shaped cutting edge 15 formed at the tip half 11 of the tooth portion 1 and a portion corresponding to the bent portion 10 of the tooth portion 1 cut away the material to be cut (FIG. 3). reference).
Since each saw blade unit 4 of the grass cutting blade according to the present invention is fixed to the outer periphery 6a of the base portion 6 as described above, the saw blade units 4 may be rattled or wavy during the mowing operation. There is no, and it can be brushed smoothly.
On the other hand, although not shown in the drawings, the chainsaw chains that have been used in the past are formed by connecting a plurality of cutting links with pins, so that during cutting, each cutting link rattles and is in a stable state. It will hinder logging.

FIG. 6 shows the relationship between the sharpness of the mowing blade and time when a general user actually uses the mowing blade of the present invention and the mowing blade provided with the tip blade of Patent Document 1 above. In FIG. 6, when the tooth portion 1 of the grass cutting blade according to the present invention becomes poor and becomes 19, the user does not need a professional polishing operation with a diamond tool, and the user can use a round file for polishing a chain saw. The sharpness can be increased to 20 by polishing with Thus, every time the sharpness of the tooth portion 1 is lowered, the sharpness can be improved by performing the polishing operation, and the polishing operation is easy.
On the other hand, the mowing blade of Patent Document 1 has a property that, as shown by a one-dot chain line in FIG. In order to improve the sharpness of this super steel chip, it is difficult for general users because it requires a skilled polishing operation using a diamond tool. If the sharpness is further reduced, the mowing blade itself may be discarded. Not a few.
As can be seen from FIG. 6, the grass cutting blade of the present invention can be easily polished by the user himself / herself, and the sharpness is improved again by the polishing so that the mowing operation can be performed smoothly. One mowing blade can be used for a long time.

As described above, the grass cutting blade according to the present invention has a large number of sawtooth units 4 having a predetermined pitch P and the same steel plate as the base portion 6 on the outer periphery 6a of the disc-shaped base portion 6 made of a steel plate. Each saw-tooth unit 4 is composed of a cut depth limiting protrusion 3, a recess 2, and a tooth 1 in order from the upstream to the downstream in the rotation direction, so that it is easier for the user himself / herself. The sharpness can be increased by polishing. Therefore, unlike a mowing blade having a tip attached to a tooth portion, a single mowing blade can be used in a sharp state for a long period of time without performing specialized polishing using a diamond tool.
Further, since the sawtooth units 4 are integrally provided on the outer periphery 6a of the disk-shaped base portion 6, the sawtooth units 4 are not rattled or undulated during the mowing operation, and smoothly. You can mow.
Moreover, since the depth which each tooth | gear part 1 cuts with respect to a to-be-cut material is restrict | limited by the cutting depth restriction | limiting protrusion 3, cutting can be performed smoothly.

  Further, the tooth portions 1 of the many sawtooth units 4 are formed so that the front half portions 11 are alternately bent in opposite directions, so that the tooth portions 1 cause kickback while the material to be cut is cut. Is prevented and has durability.

  Further, the tooth portion 1 of the multiple sawtooth units 4 has its proximal half 13 alternately bent once in a reverse direction with a gentle inclination angle α of 5 ° to 40 °, and the diameter of the proximal half 13. The front end half 11 connected to the outer end in the direction is folded back in the opposite direction, and the front end half 11 is provided in an orthogonal direction substantially orthogonal to the base body 6. Since the substantially L-shaped cutting edge 15 is formed over the part, the substantially L-shaped cutting edge 15 is a part formed at the tip half 11 of the tooth part 1 and a part corresponding to the bent part 10 of the tooth part 1. However, since the material to be cut at the side and the lower side of the saw-tooth units 4 is cut off, a wide range of cutting can be performed, and the working efficiency is very good. Further, the tooth portion 1 is prevented from kicking back while the material to be cut is cut, and is not easily deformed.

In the tooth portion 1 of each saw tooth unit 4, the rake angle θ of the tip edge 12 of the tip half 11 is set to 25 ° to 35 °, so that the cutting performance is very good and the brushing operation can be performed smoothly.
Further, since the rake angle θ of the substantially L-shaped cutting edge 15 is set to 25 ° to 35 °, the cutting performance is very good and the brushing operation can be performed smoothly.

  Moreover, since the base part 6 and the sawtooth unit 4 are subjected to a parkerizing process after quenching, the entire cutting blade has a high strength and is not easily deformed. By being treated, it has a function of rust prevention. Therefore, the grass cutting blade has great durability and long-lasting.

It is a top view which shows one Embodiment of the mowing blade which concerns on this invention. It is a principal part top view. FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2. It is a BB cross-sectional arrow view of FIG. It is a principal part perspective view. It is a graph which shows the relationship between each sharpness of the grass cutting blade of this invention, and the grass cutting blade of patent document 1, and time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tooth part 2 Recessed part 3 Cutting depth restriction protrusion 4 Sawtooth unit 6 Base part 6a Outer periphery
11 Tip half
13 proximal half
15 L-shaped cutting edge α Inclination angle θ Rake angle P Predetermined pitch

Claims (6)

  On the outer periphery (6a) of the disk-shaped steel plate base portion (6), a large number of sawtooth units (4) are integrally formed with a predetermined pitch (P) and the same steel plate as the base portion (6). Each saw-tooth unit (4) is formed in order from the upstream to the downstream in the rotational direction from the cut depth limiting projection (3), the recess (2), and the tooth (1). A mowing blade characterized by comprising.   The cutting blade according to claim 1, wherein the tooth portions (1) of the plurality of saw-tooth units (4) are formed so that the tip half portions (11) are alternately bent in opposite directions.   The tooth portions (1) of a number of the sawtooth units (4) are bent once at their base half portions (13) alternately with a gentle inclination angle (α) of 5 ° to 40 ° in opposite directions. The front end half (11) connected to the radially outer end of the base end half (13) is folded back in the opposite direction, and the front end half (11) is substantially orthogonal to the base body (6). The mowing blade according to claim 1, wherein the cutting blade is provided in an orthogonal direction, and a substantially L-shaped cutting edge (15) is formed over the entire tip half (11) and part of the base half (13).   The rake angle (θ) of the tip cutting edge (12) of the tip half (11) in the tooth portion (1) of each saw blade unit (4) is set to 25 ° to 35 °. The mowing blade described.   The mowing blade according to claim 3, wherein a rake angle (θ) of the substantially L-shaped cutting edge (15) is set to 25 ° to 35 °.   The grass cutting blade according to claim 1, 2, 3, 4 or 5, wherein the base body (6) and the sawtooth unit (4) are subjected to a parkerizing treatment after quenching.

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