JP3008290U - Tip saw for brush cutter - Google Patents

Abstract

(57) [Abstract] [Purpose] A saw for a brush cutter, in which a tooth profile 2 is formed on the outer peripheral portion of a disk-shaped blade plate 1 at equal intervals, and a cemented carbide tip 3 is joined to the front end of each tooth profile. Not only small shrubs and small shrubs but also various cutting objects such as vines and bamboo grass that are difficult to cut can be mixed efficiently, it is possible to efficiently mow the forest under severe conditions. The purpose is to be able to easily re-polish by using. [Structure] The cemented carbide tip 3 has a front end surface 3a formed in an arc shape with the front center O ₁ and extending from the blade tip 3b to the tip tooth bottom portion 3c, and a part of the blade plate in front of the cemented carbide tip 3. Is cut into an arc shape that is continuous with the shape of the front end surface of the cemented carbide tip 3 and has a shape that can be applied with a cylindrical round file. Also,
The front end surface 3a of the cemented carbide tip 3 forms a relatively large lead angle (side scooping angle) over its entire length to cause the side edge to act as a cutting edge, so that the object to be cut taken in front of the cemented carbide tip 3 Allows cutting at the front end face 3a.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a tip saw for a brush cutter, in which a large number of tooth profiles are formed on an outer peripheral portion of a blade plate at equal intervals and a tungsten carbide carbide tip (hereinafter referred to as a carbide tip) is joined to a front end portion of each tooth profile. This is a device relating to a tip saw particularly suitable for cutting under the forest.

[0002]

[Prior art]

 Tipped saws for brush cutters, in which carbide tips are joined to the outer periphery of the blade plate, have been used for cutting rice ridges, banks, road shoulders and park weeds. In the general structure of a conventional chip saw for a brush cutter, it is usual to join a rectangular cemented carbide tip to the front end face of the tooth profile formed on the outer peripheral portion of the blade plate. In the conventional tip saw, the cemented carbide tip during use is often chipped or dropped, but in order to improve this, the applicant of the present invention has shown that the tip of the tooth profile B formed on the outer peripheral portion of the blade plate A as shown in FIG. , We are developing a brush saw tip saw (actual fair 3-23055) that joins the tapered tip C diagonally backward.

[0003]

[Problems to be solved by the device]

 In all of the conventional saw tips for mowers, only the tip of the carbide tip acts as a cutting blade, and most of them are used only for weeding weeds, etc. Therefore, it has not been widely used in the cutting of forests, which is the most severe use condition of the bush cutter. The reason for this is that the tip saw is expensive, but in the undercut of a forest where a large amount of mowing is performed under severe conditions, even with a tip saw, the cutting edge becomes worn, and it is necessary to re-grind (re-dress) it. Occurs. However, the conventional cemented carbide tip requires a special grinder to grind it, which is not suitable for cutting down forests that require long-term mountain climbing and is relatively easy to grind. A steel shaving blade that can be used has been used.

In view of the above situation, the present invention can relatively easily re-polish using a simple tool, a diamond electroplated round file, and simply cuts weeds and shrubs. Not only that, but we also devised a tip saw for brush cutters that has a carbide tip with a shape that can efficiently cut what was difficult to cut with conventional carbide tip saws such as vines and bamboo grass. .

[0005]

[Means for Solving the Problems]

In the tip saw for a brush cutter, a tooth profile 2 is basically formed on the outer peripheral portion of a disk-shaped blade plate 1 at equal intervals, and a cemented carbide tip 3 is joined to the front end thereof. In the present invention, the shape of the cemented carbide tip 3 to be joined to the front end of the tooth profile 2 is such that the front end face 3a thereof is centered on the front of the cemented carbide tip O ₁ and has an arc shape extending from the cutting edge 3b to at least a part of the tooth bottom. At the same time, the tooth bottom of the blade plate in front of the cemented carbide tip is cut into an arc shape continuous with the front end face 3a of the cemented carbide tip 3. Further, the plurality of cemented carbide tips 3, 3 to be joined to the front ends of the tooth profiles 2, 2 are formed such that the side edges of the front end surface 3a serve as cutting edges, and the front end surface of each cemented carbide tip extends from the cutting edge 3b to the tooth bottom portion 3c. A relatively large lead angle (lateral scooping angle) λ is formed over the entire length up to.

The shape of the tooth profile 2 of the blade plate 1 is such that the tooth bottom is gently continuous to the front flank of the tooth profile, or the cemented carbide tip is joined as a whole from the tip of the tooth profile toward the diagonal rear. It is effective to make the upper half of the front end surface 3a of the cemented carbide tip linear.

[0007]

[Action]

 When the blade plate 1 is rotated and used for mowing, the cutting edge 3b acts as a cutting blade, and at the same time, the lead angle of the front end face 3a is set to a relatively large angle, so it is taken into the gullet part in front of the carbide tip 3. The left or right side edge of the front end face 3a extending from the tip tooth bottom portion 3d to the cutting edge 3b of the cut object acts as a cutting blade. Therefore, mainly small shrubs are cut with the cutting edge 3b, while soft and flexible materials like vines and slippery materials such as bamboo grass are taken in front of the tooth profile 2 and cut at the front end surface 3a of the cemented carbide tip. To be done.

The re-polishing of the cemented carbide tip is carried out manually by using a diamond electroplated round file 5 which has a cylindrical shape and whose surface is coated with fine diamond powder. That is, since the front end surface 3a of the cemented carbide tip is arcuate and a part of the blade plate in front of the cemented carbide tip is cut in an arcuate shape continuous with the front end surface 3a of the cemented carbide tip, It is possible to apply a round file.

As shown in FIGS. 3 and 4, the direction of sanding is the direction along the scooping surface of the front end face 3a of the cemented carbide tip 3, that is, the direction of the lead angle λ as shown in FIG. Then, the worn state shown in FIG. 5 (b) is polished as shown in FIG. 5 (c), and the cutting blade of the entire cemented carbide tip is regenerated.

[0010]

【Example】

 An embodiment of a tip saw for a brush cutter according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a front view of the entire tip saw for a brush cutter. A large number of tooth profiles 2 and 2 are formed on the outer peripheral portion of a disc-shaped blade plate 1 at equal intervals, and a carbide tip 3 is formed on the front end of each tooth profile 2. Is brazed. In the figure, a part of the tooth profile 2 where the chip 3 is joined is shown in an enlarged manner.

The tooth profile 2 has a sawtooth shape in which the tooth bottom part is smoothly continuous to the flank of the tooth profile of the tip side, and the cemented carbide tip 3 is brazed to the front end of each tooth profile 2. The height of the front end surface 3a of the cemented carbide tip 3 from the cutting edge 3b to the bottom of the tooth, that is, the total height of the tooth profile, and the shape of the front end surface 3a as viewed from the front of FIG. ), The radius of curvature is slightly larger than one half of the tooth height, and it is formed in an arc shape with the center O _{1 at} the front position approximately in the middle of the tooth height. A part of the blade plate in front of the cemented carbide tip (root portion) is cut in an arc shape centered on O ₁ and continuous with the front end face 3a of the cemented carbide tip 3, and the cut portion 4 is a part of a shallow garette. To form.

In the illustrated embodiment, the upper half of the front end face 3a of the arc-shaped cemented carbide tip is formed in a straight line to form a straight scooping surface 3d, and the tip edge 3b is set to a desired scooping angle. γ. The scooping angle γ is about 20 degrees, which is sharper than the scooping angle of about 10 degrees of the conventional tip saw. Therefore, with a tool with such a large scooping angle, the cutting edge is formed sharply and it is not only possible to cut small trees and weeds with less resistance, but the object to be cut is drawn into the front end surface 3a of the carbide tip. It becomes easy to be damaged. The clearance angle α of the upper surface of the carbide tip is about 10 degrees, which is the same as the conventional one.

The front end surface 3a of the cemented carbide tip 3 has a total height range from the cutting edge 3b to the tooth bottom portion 3c so that either the left or right side edge alternately acts as a cutting blade. It has a large lead angle (lateral scooping angle) λ. Since the lead angle λ is much larger than the lead angle of the conventional tip saw of about 5 degrees, that is, about 20 degrees as shown in FIG. It has a sharp cutting edge. In the illustrated embodiment, the lead angles are formed in alternating left and right directions, but they may be in the same direction. However, if the cutting blades are formed alternately on the left and right, they act like saw teeth, and can be used not only for weeding or weeding under bamboo but also for cutting standing trees up to a diameter of about 50 mm.

The overall shape of the cemented carbide tip brazed to the front end of the tooth profile 2 is that the lower surface 3e is the extension direction of the flank surface 2a of the front tooth profile, the rear end surface 3f is the inclined surface of the front end surface 3a in the scooping angle direction, The upper surface is used as the flank of the cutting edge 3b, and the cutting force acting on the front end surface 3a or the cutting edge 3b, which is generally rhombic as a whole, presses the cemented carbide tip 3 against the blade plate 1 and stabilizes it firmly It is shaped like this. This basic idea is in common with the idea of Jikken 3-23055.

Next, the abrasion and re-polishing of the cemented carbide tip will be described. When the tip saw in the initial state shown in Fig. 5 (a) is used to continue the work, as shown in Fig. 5 (b), the side edges of the cutting edge 3b and the front end face 3a, which are cutting edges, are worn away. And the sharpness is getting worse. When the sharpness is lowered, the individual cemented carbide chips 3 are polished using a round file 5 having a cylindrical shape and electrodeposited diamond as shown in FIGS. 3 and 4. The direction of polishing by the round file 5 is the direction coinciding with the scooping surface of the chip front end surface 3a, that is, the direction slightly oblique when viewed from the front as shown by the arrow in FIG. 3, and the plane as shown by the arrow in FIG. As seen from the above, by sanding in the direction of the lead angle, it can be re-polished to the state shown in FIG. 5 (c).

In the state of being polished by the round file, the front end face 3a of the carbide tip is an arc shape having the curvature center at the point O ₂ which is moved backward by the polishing amount, and is continuous from the cutting edge 3b to the tooth bottom portion 3c of the front end face of the tip. Is polished to eliminate straight parts. At this time, the cutout portion 4 of the blade plate is also cut rearward according to the polishing amount of the cemented carbide tip. When this re-polishing is repeated n times, the arc-shaped curvature center O _{n of} the front end face 3a also gradually moves rearward, and eventually the entire carbide tip is used up. In that case, the material of the blade plate should be selected so that it can be used as a steel brush blade.

In the above-mentioned embodiment, the straight scooping surface 3d is formed on the upper half of the front end surface 3a of the cemented carbide tip, but it is needless to say that the straight scooping surface 3d may be formed in a continuous arc shape up to the upper end. It However, when forming a continuous arc shape up to the upper end, depending on the radius of curvature of the arc shape, the rake angle of the cutting edge 3b in the initial state is too large and sharp, and the chip is likely to break or fall off in terms of strength. Although there is a possibility, it is possible to form a constant scooping angle by forming the straight scooping surface 3d.

It is known that in a tip saw for a lawn mower, a slight runout occurs at the beginning of use due to familiarity with the rotating shaft and a slight difference in processing accuracy, and as the use progresses, the initial runout disappears. Has been. Therefore, if the cutting edge 3b in the initial state is too sharp, it is more likely to be damaged or fall out, but when re-polishing, the initial vibration of the blade plate is also eliminated, and the rake angle of the cutting edge is slightly sharpened. Even if it is damaged, the chip is unlikely to drop or drop out. Further, when the carbide tip is worn, the blade tip 3b, which bears the greatest load, is rounded as shown in FIG. 5 (b). To completely eliminate this, a large amount of grinding must be done, but as shown in Fig. 5 (c), if grinding is done with the round file 5 until the cutting edge is slightly rounded, the result is the same as the initial rake angle. It will be polished to a small scoring angle, and it will be possible to efficiently re-polish to the optimum state.

[0019]

[Effect of device]

 According to the tip saw for a brush cutter of the present invention as set forth in claim 1, not only is the blade tip of the cemented carbide tip relatively easy to cut, but also the conventional tip saw is difficult to cut because of vines and vines. , Such as bamboo grass, which is slippery and is difficult to cut by just cutting with the cutting edge, pulls various objects to be cut into the gullet part in front of the cemented carbide tip, and spreads over the entire side edge of the front end surface of the carbide tip. It can be efficiently cut with the sharp cutting edge that is formed, and can be used for cutting down forests where various objects are mixed.

Although the sharp cutting edge is accompanied by wear of the cutting edge, the present invention uses a round file capable of polishing a cemented carbide tip to easily and compare. It can be re-polished accurately.

According to the second aspect of the invention, the rake angle of the cutting edge in the initial state is too large, the cutting edge becomes unnecessarily sharp, and the initial vibration when the blade plate is used causes the chipping or dropping of the cemented carbide tip. This can be avoided, and a sharp cutting edge can be formed with a relatively small amount of polishing during re-polishing.

According to the third aspect of the present invention, when the above-described tip saw for a brush cutter is used, the object to be cut is easily guided to the front surface of the cemented carbide tip.

According to the invention of claim 4, when cutting resistance acts on the cutting edge or front end face of the cemented carbide tip of the above-mentioned tip saw for brush cutter, the cutting resistance presses the cemented carbide tip against the blade plate. It acts in a directional manner and makes the cemented carbide hard to fall off.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a tip saw for a brush cutter according to the present invention, which is partially enlarged.

FIG. 2 is a plan view showing, in an enlarged scale, only a part where cemented carbide chips are joined,

FIG. 3 is a front view showing a state of re-polishing a carbide tip;

FIG. 4 is a plan view showing a state of re-polishing a carbide tip;

FIG. 5 is a front view sequentially showing changes in a state in which a carbide tip is worn and re-polished.

FIG. 6 is a front view of only a part showing an example of a conventional tip saw for a brush cutter.

[Explanation of symbols]

1 ... Blade plate, 2 ... Tooth profile, 2a ... Tooth flank face, 3 ... Carbide tip, 3a ... Front end face, 3b ... Blade tip, 3c ... Tip bottom part, 3d ... Straight scooping surface, 3e ... Bottom face, 3f ... Rear End face,
4 ... excision part, 5 ... round file.

Claims (4)

[Scope of utility model registration request] 1. A tooth profile 2 is provided at equal intervals on an outer peripheral portion of a disk-shaped blade plate 1.
In the tip saw for a bush cutter, which forms a tooth and joins the cemented carbide tip 3 to the front end of the tooth profile 2,
Is centered on the front of the carbide tip O ₁ and has an arc shape extending from the cutting edge 3b to at least a part of the tooth bottom, and the tooth bottom portion of the blade plate in front of the carbide tip is the front end surface 3a of the carbide tip 3. The front end faces of the plurality of cemented carbide tips 3, 3 joined to the front end of the tooth profile 2 formed on the outer peripheral portion of the blade plate 1 should have left and right side edges alternately serving as cutting edges. A tip saw for a brush cutter, wherein each of the carbide tips has a relatively large lead angle λ formed over the entire length from the cutting edge 3b to the tooth bottom portion 3c. 2. A tip saw for a bush cutter according to claim 1, wherein the upper half of the front end surface 3a of the cemented carbide tip 3 has a straight scooping surface 3d formed by linearly forming a part of an arc shape. 3. A tooth profile 2 formed at equal intervals on the outer peripheral portion of a disk-shaped blade plate 1 has a shape in which the tooth bottom portion at the front end of the tooth profile is smoothly continuous to the flank surface 2a of the tooth profile at the front. The tip saw for a brush cutter according to claim 1. 4. The cemented carbide tip 3 to be joined to the front end of the tooth profile 2,
The lower surface 3e is the extension direction of the flank 2a of the front tooth profile, the rear end surface
3f is an inclined surface that inclines in the direction of the rake angle of the front end surface, and the upper surface is the cutting edge
The tip saw for a brush cutter according to claim 1, wherein the flank surface of 3b is joined to the front end of the tooth profile 2 in a diagonally rearward direction.