JPH07227124A - Tip saw for bush and grass clearing - Google Patents

Abstract

PURPOSE:To remarkably improve the cutting quality, durability and safety of a cutting blade by preventing the cutting blade of cemented carbide tips fused to a saw blade from abrading, breaking and damaging and eliminate the scattering of the tips caused thereby. CONSTITUTION:This tip saw for bush and grass clearing is equipped with cutting blades 7 and 8 between protruding parts to which cemented carbide tips 6 are fused at a suitable interval around a steel plate of a saw blade body.

Description

Detailed Description of the Invention

(1) Industrial field of application: The present invention relates to a tip saw having a super hard tip installed. Particularly, regarding a tip saw for cutting bushes, a large number of hard objects are scattered at the cutting place and saw blades are used during operation. However, the tip of the tip is sometimes subjected to a large impact when it comes into contact with a hard material, and the tip may inevitably be broken and scattered, resulting in a great loss and a danger. The present invention is intended to eliminate the drawbacks of these conventional tip saws and to realize a tip saw having excellent sharpness, durability and safety. (2) Prior art: Most of the tip saws for vegetation are substitutes for wood and woodwork at present, but it is a well-known fact that about 8 blades are the most suitable for mowing vegetation. However, after all, in the case of 8 blades with a large distance between the blades, the impact when contacting the hard object received by the chip welded to it is too large, and the chip is inevitably damaged or extremely worn Therefore, up until now, we have not realized such a cutting saw with a small number of blades that can be practically used. In the past, when cutting grass in the steel blade age, eight blades were 70
The saw blade for woodworking and sawing, which has a large number of blades, is rarely used except for undercutting of forests. This fact proves that the cutting blades with around 8 blades having a small number of blades were superior to the saw blades with a large number of blades in terms of reaping of vegetation. When entering the era of carbide tip saws, carbide tips that are strong against wear but weak against impact have to cut while contacting hard objects from beginning to end. The current situation is to use a tip saw for woodworking and wood, which is a common saw blade. Many people made efforts to develop and manufacture 8 blades with a small number of blades, but the distance between the blades is wide and the impact on the tip is larger than expected, so the carbide tip will be broken or broken immediately.
It did not reach the stage of wear. It is well known that in the age of steel plate blades, saw blades with around 8 blades, which have few blades, are more than several times more durable than saw blades for woodworking and lumber with around 40 blades, which have many blades. Despite this fact, cutting blades with a small number of blades have not been developed and put into practical use, so the present situation is that saw blades for woodworking and sawing are substituted. (3) Problem to be Solved by the Invention: In the present invention, the most important drawback of the mowing tip saw is breakage and crushing of the tip during work, which is eliminated, and only the abrasion of the tip is used. If it is only damaged, the durability of the saw blade is dramatically improved, and it is a safe and economical saw blade. However, it is concluded that it is an uneconomical saw blade that is highly worn, but lacks in toughness, and is very economically worn, and many people still use steel plate blades. Is. The present invention intends to further improve the wear resistance of the above-mentioned tip saw, to additionally install a device for reinforcing the lack of toughness, and to drastically improve the durability time of the mowing tip saw. (4) Means to solve the problem: A tip protection protrusion is provided on the front of the carbide tip of the tip saw, and at the same time as the front edge of the cutting edge and the outer peripheral portion of the carbide tip wears during work, the front surface of the defense protrusion simultaneously. And the outer circumference also wear, and the outer circumference and the front surface of the convex part always wear more than the tip, and using the wear theory of the saw blade, the tip is an unnecessary hard material other than vegetation. The tip is protected by a protective convex part so that it does not come in contact with (rocks, gravel, gravel, and other hard objects), and the chip is protected from the impact due to contact with hard objects to increase the service life of the chip. . (5) Operation: Since the breakage and damage due to the impact with the hard material, which is the weak point of the hard tip, is minimized, the durability of the tip is extended and the change of the tip shape due to the abrasion damage of the tip is extremely changed. Since the number of blades decreases, even if the saw blade is used for a long time, the diameter of the entire saw blade is slightly reduced. This also concludes that there is little change in the sharpness of the entire saw blade. Detailed principle operation will be described in detail with reference to the embodiments. (6) Description of Examples and Drawings: The basic action of the examples will be described. (6) in FIG. 7 shows the velocity and angle at which plants and hard objects jump into the cutting blade when using the saw blade, expressed as a vector, where R is the peripheral speed when the saw is used, and F is The feed rate (the speed at which the mower is shaken) FC is the resultant force and direction. Normally, the number of rotations of a brush cutter depends on the person and the plants to be mowed, but the approximate value used during design is R = 50.
m / s to 15 m / s and F = 1.0 m / s to 1.5 m /
s. For example, assuming that F = 1.3, FC dive angle θ =
It is 1.5 ° to 5 °. From the above theory, Tan θ
= F / R and the average value is F = 1.3 m / s R = 30 m / s
Then, Tan θ = 1.3 / 30 = 0.0433 θ =
It is 2.5 °. Since the distance between the blades of eight blades with a diameter of 255 mm is L + l≈10 cm, the cutting width of the cutting object on the tip of the cemented carbide tip having the blade tip on the outermost circumference is 100 mm ×
0.043 = 4.3 mm. This cutting width changes in inverse proportion to the rotational speed of the saw. For example, a 40-blade saw has a cutting width of 0.8 mm or more. Defense convex part (2)
The outermost tips of the front cutting edge (4) and the rear cutting edge (5) are larger in the cutting edge (5) than in the cutting edge (4) with respect to the rotation direction of The difference (S) between the tip of the outermost periphery of the hard tip (6) and the tip of the cutting edge (5) is maintained at a distance of about 1 mm lower at the cutting edge (5) and follows the wear of the tip (6). Wear out. In this case, due to the principle of wear of the rotating body, the cutting edge (4) is worn lower than the cutting edge (5), and the resulting tip of the cutting edge (4) and the tip of the cutting edge (5) are chips. The difference (T) with respect to the tip is larger than the difference (S),
Also, the line connecting these is the angle of rising from the front to the rear from the center, and the formed angle of rising is increased / decreased in inverse proportion to the rotation speed of the saw blade.
The height difference (S) between the sharpest cutting edge (5) of the blade and the tip of the tip (6) also changes in inverse proportion to the rotation speed of the saw blade (1), and in proportion to the distance between the blades (L + 1). Increase or decrease. That is, a saw blade with a small number of blades has a large difference, and a saw blade with a large number of blades has a small difference. The factors of the above change are the rotational speed, that is, the peripheral speed
It is the distance between the blades (L + 1) and is mainly the number of saw blades. FIG. 7 (a) shows that the hard material (m) has a plunge angle of 2 ° to 5 °.
It shows a state that it entered at an angle of ° and was pushed out to the outside at the outer peripheral portion (the line connecting B-C) of the defense convex portion. At this time, it is needless to say that the plant has a root diameter and adheres to the ground, and is soft, so that it is cut without being repelled to the outside. FIG. 1 shows an 8-blade tip saw, but it is a saw blade for medium speed and has a small distance from the cutting edge portion (3) in front of the protective convex portion,
Therefore, since the cutting width is small, the outer peripheral part of the protection convex part is not necessary, and most hard materials are pushed out by the protection cutting blade (4) which is a slope against rotation and the result protects the following cutting blade. Only the vegetation is sorted and cut by each cutting edge that follows the rear. This saw blade uses both sides, and if it becomes difficult to cut, it can be turned over and installed so that the cutting work can be performed by the cutting blades (5) and (8) installed on the opposite side. Fig. 2 is a saw-tooth type with double-sided use. The cutting edge of the protective convex part is only slightly higher than the front cutting edge, and the impact of the hard objects is also absorbed in sequence, so there are relatively few protective convex parts. , Those with such a saw-tooth cutting blade are often used in places with few hard objects. As shown in Fig. 3 by a low-speed saw blade in vector form, the plunge angle (θ ') is large and the cutting width is large, so the chip is severely damaged. For this reason, the interval between the protective convex portion and the chip is reduced. ,
In addition, a hard object probably also enters the protective convex part, so the cutting edge (4) that prevents it and the outer peripheral part of the cutting edge also hold an inclination to alleviate the impact with the hard object, and stroke the plant It has become. Fig. 4 shows that the hardness is very hard, but on the other hand it is a cermet tip that is very weak against impact, so it is not possible to give an impact at once, so it is made to come into contact with a hard object gradually. Then, as shown by the dotted line in FIG. 7 (a), at the beginning of use, first the cutting work is carried out with the cutting blade (4) whose tip of the cutting edge protrudes from the outer peripheral tip of the tip. In FIG. 7 (a), AB- surrounded by a dotted line
Eventually, the part C disappears due to wear, and the outer peripheral part is BC
In that case, the difference (S) between the tip of the tip and the tip of the cutting edge (5) is 8 blades, so about 1 mm is retained and follows the wear of the tip. Wear out. However, the inclination angle of B-C is gentle when the rotation of the saw is high, and the angle is large when the rotation of the saw is low, and the blade wears. As described above, the tip begins cutting work as the outer periphery of the protection plate is worn out during use, and finally the difference between the tip and the cutting edge (5) is maintained at about 1 m / m for cutting work. To last. Fig. 5 is for underforest cutting (dedicated blade for wood, vegetation, etc.) and has cutting blades (4), (5) in front of the tip cutting blade (6).
Since the protective convex portion (2) with a blade is installed and the interval between the blades is narrow, the protective action of the tip (6) of the protective convex portion is that of the cutting edge (4) and the cutting edge (5) of the outer peripheral portion. The vegetation having the root diameter only near the apex of the obtuse angle of the intersection is cut by the following series of chip blades (6), but the hard material is pushed outward by the inclined surface of the apex. In this case, the difference (S) held between the tip of the protection protrusion and the tip of the tip is 0.2 to 0.4 m / m in this case (since it is 48 blades). This has been confirmed by experiments. FIG. 6 shows a 6-blade tip saw for low speed, but the tip blade (6) is protected from hard objects by the cutting blade (4) and the cutting blade (4).
It is a saw blade which is performed by the outer peripheral portion connecting the cutting edge (5) and the cutting edge (5). The angle of the inclined surface of the cutting blade (4) increases / decreases in inverse proportion to the rotation speed, and the radius from the center of its operating portion is proportional to the rotation speed of the saw blade, but its cutting width is inversely proportional to the rotation speed of the saw blade. . FIG. 8 shows a part of a double-sided three-blade in which the protection projections of FIG. 6 are installed in the left-right direction, and the principle of operation is similar to that shown in FIG. (7) Advantages of the Invention: At present, the drawback of a tip saw is that it is very brittle, and its advantage is that it is extremely hard and therefore it is resistant to wear. This development solves this drawback and raises the advantage even further, and its technical effect has succeeded in sustaining the service life of conventional tip saws by a factor of three to several times. This is a national loss in view of the fact that the chips of the saw blade are severely damaged and broken, and therefore the saw blades are left unusable despite being left in a state close to the current state. What was able to overcome this situation this time is to provide a protective convex portion on the front surface of the tip, and to adjust the inclined surface and outer peripheral portion of this cutting edge, and the height of the convex portion according to the rotation speed and the number of blades of the saw blade. By appropriately changing the above, the brittleness of the chip is protected by the toughness of the convex portion of the steel sheet, and it is possible to utilize only the advantage of abrasion resistance. This is a factor in which the installation of the protective convex portion of the steel plate is large and is not very important.

[Explanation of symbols]

 : (1) …… Blade (desk) (2) …… Defense convex part (3) …… Cutting edge part (4). (4 ') ... cutting edge (defense section cutting edge) (5) ... cutting edge (defense section cutting edge) (6). (6 ') ... Carbide tip (7). (7 ') …… cutting edge (8) …… cutting edge

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[Procedure amendment]

[Submission date] July 18, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Detailed explanation of the invention

[Correction method] Change

[Correction content]

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tip saw having a super hard tip installed, and in particular for a tip saw for cutting bushes, a large number of hard objects are scattered at the cutting site, and the saw blades are hard during operation. The tip of the tip is sometimes subjected to a large impact when it only comes into contact with an object, and the tip may inevitably be broken and scattered, resulting in a great loss and danger. The present invention eliminates the drawbacks of these conventional tip saws,
It is intended to realize a tip saw that has excellent sharpness and is highly durable and safe.

2. Description of the Related Art Currently, most tip saws for plants are for wood,
Woodworking ones have been used instead, but for cutting bushes 8
It is a well-known fact that the one with a single blade is best,
After all, if there are around 8 blades with a large distance between the blades, the impact when the tip welded to the hard object is too large and the tip is inevitably damaged or extremely worn, Until now, we have not realized a cutting saw with a small number of blades that can be used practically. In the past, eight blades accounted for nearly 70% of grass cutting blades in the age of steel plate blades, and saw blades for woodworking and sawing, which had a large number of blades, were rarely used except for cutting under the forest. . This fact proves that the cutting blades with around 8 blades having a small number of blades were superior to the saw blades with a large number of blades in terms of reaping of vegetation. When entering the era of carbide tip saws, carbide tips that are strong against wear but weak against impact have to cut while contacting hard objects from beginning to end. The current situation is to use a tip saw for woodworking and wood, which is a common saw blade. Many people have made efforts to develop and manufacture 8 blades with a small number of blades, but the distance between the blades is wide and the impact on the tip is greater than expected, so the carbide tip immediately breaks, breaks, and wears out. I didn't use it. It is well known that in the age of steel plate blades, saw blades with around 8 blades, which have few blades, are more than several times more durable than saw blades for woodworking and lumber with around 40 blades, which have many blades. Despite this fact, cutting blades with a small number of blades have not been developed and put into practical use, so the present situation is that saw blades for woodworking and sawing are substituted.

DISCLOSURE OF THE INVENTION The present invention provides a cutting tip saw with a large number of breakages and crushes during work, which is the greatest drawback of the cutting tip saw. Therefore, this problem is solved, and damage is caused only by abrasion of the tip. If it is stopped, the durability of the saw blade is dramatically improved, and it is a safe and economical saw blade. However, it is concluded that it is an uneconomical saw blade that is highly worn, but lacks in toughness, and is very economically worn, and many people still use steel plate blades. Is.
The present invention intends to further improve the wear resistance of the above-mentioned tip saw, to additionally install a device for reinforcing the lack of toughness, and to drastically improve the durability time of the mowing tip saw.

[Problems to be Solved by the Invention] A tip convex portion is provided on the front part of a cemented carbide tip of a tip saw, and at the same time as the front surface and outer peripheral portion of the cutting edge of the cemented carbide tip are worn during work, the front surface and outer periphery of the protective convex portion simultaneously The wear theory of the saw blade says that the parts also wear along with each other, and that the outer peripheral part and the front surface of the convex parts always wear more than the tip. , Gravel, gravel, and other hard materials) are protected from contact with the protective projections to protect the chips from impact due to contact with hard materials, thereby increasing the life of the chips.

[Function] Since the breakage and damage due to impact with a hard object, which is a weak point of the hard chip, is minimized, the durability of the chip is prolonged and the change of the shape of the chip due to abrasion damage of the chip is extremely reduced. Even when used for a long time, the diameter of the entire saw blade is slightly reduced. This also concludes that there is little change in the sharpness of the entire saw blade. Detailed principle operation will be described in detail with reference to the embodiments.

Description of Embodiments and Drawings The basic action of the embodiment will be described. (6) in FIG. 7 shows the velocity and angle at which plants and hard objects jump into the cutting blade when using the saw blade, expressed as a vector, where R is the peripheral speed when the saw is used, and F is The feed rate (the speed at which the mower is shaken) FC is the resultant force and direction. Normally, the number of rotations of a brush cutter depends on the person and the plants to be cut, but the approximate value used during design is R = 50m.
/ S to 15 m / s and F = 1.0 m / s to 1.5 m / s
Is. For example, assuming that F = 1.3, FC dive angle θ =
It is 1.5 ° to 5 °. From the above theory, Tan θ
= F / R and the average value is F = 1.3 m / s R = 30 m / s, Tan θ = 1.3 / 30 = 0.0433 θ =
It is 2.5 °. Since the distance between the blades of eight blades with a diameter of 255 mm is L + l≈10 cm, the cutting width of the cutting object on the tip of the cemented carbide tip having the blade tip on the outermost circumference is 100 mm ×
0.043 = 4.3 mm. This cutting width changes in inverse proportion to the rotational speed of the saw. For example, in the case of a 40-blade saw, the cutting width is a little over 0.8 mm. Defense convex part (2)
The outermost tips of the front cutting blade (4) and the rear cutting blade (5) are larger in the cutting blade (5) than in the cutting blade (4) with respect to the rotation direction of The difference (S) between the tip of the outermost periphery of the hard tip (6) and the tip of the cutting edge (5) is maintained at a distance of about 1 mm lower at the cutting edge (5) and follows the wear of the tip (6). Wear out. In this case, due to the principle of wear of the rotating body, the cutting edge (4) is worn lower than the cutting edge (5), and the resulting tip of the cutting edge (4) and the tip of the cutting edge (5) are chips. The difference (T) with respect to the tip is larger than the difference (S),
Also, the line connecting these is the angle of rising from the front to the rear from the center, and the formed angle of rising is increased / decreased in inverse proportion to the rotation speed of the saw blade.
The height difference (S) between the sharpest cutting edge (5) of the blade and the tip of the tip (6) also changes in inverse proportion to the rotation speed of the saw blade (1), and in proportion to the distance between the blades (L + 1). Increase or decrease. That is, a saw blade with a small number of blades has a large difference, and a saw blade with a large number of blades has a small difference. The factors of the above change are the rotational speed, that is, the peripheral speed
It is the distance between the blades (L + 1) and is mainly the number of saw blades. FIG. 7 (a) shows that the hard material (m) has a plunge angle of 2 ° to 5 °.
It shows a state that it entered at an angle of ° and was pushed out to the outside at the outer peripheral portion (the line connecting B-C) of the defense convex portion. At this time, it is needless to say that the plant has a root diameter and adheres to the ground, and is soft, so that it is cut without being repelled to the outside. FIG. 1 shows an 8-blade tip saw, but it is a saw blade for medium speed and has a small distance from the cutting edge portion (3) in front of the protective convex portion,
Therefore, since the cutting width is small, the outer peripheral part of the protection convex part is not necessary, and most hard materials are pushed out by the protection cutting blade (4) which is a slope against rotation and the result protects the following cutting blade. Only the vegetation is sorted and cut by each cutting edge that follows the rear. This saw blade uses both sides, and if it becomes difficult to cut, it can be turned over and installed so that the cutting work can be performed by the cutting blades (5) and (8) installed on the opposite side. Fig. 2 is a saw-tooth type with double-sided use. The cutting edge of the protective convex part is only slightly higher than the front cutting edge, and the impact of the hard objects is also absorbed in sequence, so there are relatively few protective convex parts. , Those with such a saw-tooth cutting blade are often used in places with few hard objects. As shown in Fig. 3 by a low-speed saw blade in vector form, the plunge angle (θ ') is large and the cutting width is large, so the chip is severely damaged. For this reason, the interval between the protective convex portion and the chip is reduced. ,
In addition, a hard object probably also enters the protective convex part, so the cutting edge (4) that prevents it and the outer peripheral part of the cutting edge also hold an inclination to alleviate the impact with the hard object, and stroke the plant It has become. Fig. 4 shows that the hardness is very hard, but on the other hand it is a cermet tip that is very weak against impact, so it is not possible to give an impact at once, so it is made to come into contact with a hard object gradually. Then, as shown by the dotted line in FIG. 7 (a), at the beginning of use, first the cutting work is carried out with the cutting blade (4) whose tip of the cutting edge protrudes from the outer peripheral tip of the tip. In FIG. 7 (a), AB- surrounded by a dotted line
Eventually, the part C disappears due to wear, and the outer peripheral part is BC
In that case, the difference (S) between the tip of the tip and the tip of the cutting edge (5) is 8 blades, so about 1 mm is retained and follows the wear of the tip. Wear out. However, the inclination angle of B-C is gentle when the rotation of the saw is high, and the angle is large when the rotation of the saw is low, and the blade wears. As described above, the tip begins cutting work as the outer periphery of the protection plate is worn out during use, and finally the difference between the tip and the cutting edge (5) is maintained at about 1 m / m for cutting work. To last. Fig. 5 is for underforest cutting (dedicated blade for wood, vegetation, etc.) and has cutting blades (4), (5) in front of the tip cutting blade (6).
Since the protective convex portion (2) with a blade is installed and the interval between the blades is narrow, the protective action of the tip (6) of the protective convex portion is that of the cutting edge (4) and the cutting edge (5) of the outer peripheral portion. The vegetation having the root diameter only near the apex of the obtuse angle of the intersection is cut by the following series of chip blades (6), but the hard material is pushed outward by the inclined surface of the apex. In this case, the difference (S) held between the tip of the protection protrusion and the tip of the tip is 0.2 to 0.4 m / m in this case (since it is 48 blades). This has been confirmed by experiments. FIG. 6 shows a 6-blade tip saw for low speed, but the tip blade (6) is protected from hard objects by the cutting blade (4) and the cutting blade (4).
It is a saw blade which is performed by the outer peripheral portion connecting the cutting edge (5) and the cutting edge (5). The angle of the sloping surface of the cutting blade (4) increases / decreases while counter-pressing against the rotation speed, and the radius from the center of its action point is proportional to the rotation speed of the saw blade, but its cutting width depends on the rotation speed of the saw blade. Inversely proportional. FIG. 8 shows a part of a double-sided three-blade in which the protection projections of FIG. 6 are installed in the left-right direction, and the principle of operation is similar to that shown in FIG.

At present, the drawback of the tip saw is that it is very brittle, and the advantage thereof is that it is extremely hard and therefore it is resistant to abrasion. This development solves this drawback and raises the advantage even further, and its technical effect has succeeded in sustaining the service life of conventional tip saws by a factor of three to several times. This is a national loss in view of the fact that the chips of the saw blade are severely damaged and broken, and therefore the saw blades are left unusable despite being left in a state close to the current state. What was able to overcome this situation this time is to provide a protective convex portion on the front surface of the tip, and to adjust the inclined surface and outer peripheral portion of this cutting edge, and the height of the convex portion according to the rotation speed and the number of blades of the saw blade. By appropriately changing the above, the brittleness of the chip is protected by the toughness of the convex portion of the steel sheet, and it is possible to utilize only the advantage of abrasion resistance. This is a factor in which the installation of the protective convex portion of the steel plate is large and is not very important.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a front view of a tip saw for mowing.

FIG. 2 is a front view of the upper part of the cutting brush saw from the center.

FIG. 3 is a partial front view of the upper part of the cutting brush saw and a vector showing the angle and speed at which plants, hard particles, gravel and the like jump into the cutting blade during work.

FIG. 4 is a front view of the upper part of the cutting brush tip saw.

FIG. 5 is a front view of an upper portion of a cutting brush saw.

FIG. 6 is a front view of the upper portion of the cutting brush saw.

FIG. 7 (a) is a diagram showing movements of plants and hard objects acting on the cutting edge, and FIG. 7 (b) is a vector showing plunge angles and velocities of plants and other hard objects.

FIG. 8 is a partial front view of a cutting saw for double-sided use.

[Explanation of Codes] [1] ………… Blade (desk) [2] ………… Defensive convex part [3] ………… Cutting edge part [4], [4 '] …… Cutting edge ( Protective part cutting edge [5] ………… Cutting edge (defense part cutting edge) [6], [6 '] …… Carbide tip [7], [7') …… Cutting edge [8] …… ...... Cutting edge

Claims (5)

[Claims] 1. A defense projection (2) in which the tip of a cutting blade (4), (4 ') cutting blade (5) is held near the radius of the tip of the tip (6) in a tip saw (1). ) Is installed at the front of each tip on the circumference of the tip saw (1), and the cutting blades (4), ( 4 ') and (5) are installed, and a cutting saw tip. 2. A tip (6) in a tip saw (1).
The cutting blade saw according to claim 1, further comprising a cutting blade portion (3) having cutting blades (7) and (8) provided between the convex portions welded to each other. 3. A tip (6) in a tip saw (1).
The cutting saw according to claim 1, wherein an appropriate number of saw blades each having a triangular cutting edge are installed between the convex portions welded with each other so as to face each other. 4. In a tip saw, a protective convex portion (2) having cutting blades (4), (5) is provided on the front surface of a tip (6), and these are directed in opposite directions to form a left-right united body. The cutting saw according to claim 1, wherein an appropriate number of blades are arranged on the circumference. 5. In a tip saw, a protective convex portion (2) having cutting blades (4) and (5) is provided on the front surface of a tip (6), and an appropriate number of the convex convex portions (2) are arranged in the entire circle. The cutting saw according to claim 1, which is provided.