JPH018261Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a circular saw with a cemented carbide, such as a metal saw or a cold saw, whose cutting blade is made of cemented carbide.

Conventional circular saws of this type include those shown in FIGS. 1 and 2, for example. The circular saw with a carbide shown in these figures has a plurality of back metal parts 2 that project outward in the radial direction and are spaced apart from each other in the circumferential direction on the outer peripheral part of a circular saw main body 1. A mounting portion 3 having an L-shape when viewed from the side is formed at the front end in the rotational direction, and a cutting blade tip 4 made of cemented carbide having a cutting edge 4a is fixed to this mounting portion 3 by brazing. .

By the way, in the above circular saw with carbide, when the cutting blade 4a wears out, the outer periphery of the cutting blade tip 4 is re-ground, so when the height of the cutting blade tip 4 decreases, the back metal is correspondingly reduced. It is necessary to re-grind the outer periphery of part 2.

However, when the outer periphery of the back metal part 2 is reground, the brazing area between the back surface of the cutting blade tip 4 and the back metal part 2 gradually decreases, resulting in a decrease in brazing strength. Accidents such as falling off occurred. Once such an accident occurs, the falling cutting blade tip 4 gets caught between the following cutting blade tip 4 and the workpiece, and the cutting blade tips 4 are damaged one after another, making the entire circular saw unusable. There were times when I found myself in a situation where this happened. On the other hand, in order to avoid such a situation, it is necessary to reduce the total amount of regrinding, and therefore, conventional circular saws have the disadvantage of having a short service life.

This invention was made in consideration of the above circumstances, and aims to provide a circular saw with a carbide tip that can prevent the cutting blade tip from falling off, thereby increasing its life. purpose.

In order to achieve the above object, this invention forms a mounting groove on the outer periphery of the circular saw body adjacent to and in front of the back metal part, and inserts the inner end of the cutting blade tip into the mounting groove. The cutting blade tip is fixed to the circular saw body by brazing with the back side of the cutting blade tip in contact with the back metal part, and the two cutting blade tips are arranged adjacent to each other in the circumferential direction of the circular saw body. The cutting edge of one of the cutting edges is formed at the center of the outer circumferential side of said one cutting edge with a length of approximately half of the total blade width, and the cutting edge of the other cutting edge is formed with a length of approximately half of the total blade width. At each end of the outer peripheral side of the other cutting edge tip, approximately four quarters of the total blade width are placed so that the inner end overlaps the end of the cutting edge formed on the one cutting edge tip in the rotation locus. It is formed with half the length.

An embodiment of this invention will be described below with reference to FIGS. 3 to 7. This example is a circular saw with a carbide blade having 200 blades, a diameter of 360 mm, and a blade width of 3.5 mm.

In FIGS. 3 to 7, reference numeral 11 denotes a circular saw main body, and a plurality of back metal parts 12 protruding radially outward are formed on the outer circumference thereof, and a base end of the back metal parts 12 is formed. A mounting groove 13 extending in the width direction of the circular saw body 11 is formed adjacent to and in front of the circular saw body 11 .

This mounting groove 13 is for inserting the lower end of the cutting blade tip 14 to improve its brazing strength, and has a side surface 13a facing the rotation direction, a side surface 13b opposite to this side surface 13a, and both side surfaces. It is defined by a bottom surface 13c existing between 13a and 13b. In this case, the side surface 13a is
Wall surface 12a facing the rotation direction of the back metal part 12
It is made to continue. Furthermore, in order to improve the strength of the intersection between the bottom surface 13c and each side surface 13a, 13b, the bottom surface 13c and each side surface 13a, 13b are smoothly continuous.

In each of the mounting grooves 13 configured in this way, the lower end of the cemented carbide cutting tip 14 is attached to its back surface 14.
A is the wall surface 1 facing the rotation direction of the back metal part 12.
It is inserted in a state where it is in contact with 2a. The cutting blade tip 14 is brazed to the side surfaces 13a, 13b and bottom surface 13c of the mounting groove 13, and to the wall surface 12a of the back metal portion 12, thereby being fixed to the circular saw body 11.

Furthermore, cutting edges 15 and 16 having mutually different shapes are formed alternately in the circumferential direction at the outer circumferential end of each cutting edge tip 14. That is, as shown in FIG. 6, a cutting edge 15 consisting of divided blades 15a, 15a formed at both ends is formed at the outer peripheral end of one cutting edge tip 14. Further, a cutting edge 16 is formed at the center of the outer circumferential end of the cutting edge tip 14 adjacent to one cutting edge tip 14 in the circumferential direction. When the total blade width is W, the divided blade 15
The blade width of a is set to 1/4W+α, and the blade width of the cutting blade 16 is set to 1/2W+2α. Therefore, the cutting edge 16
The ends thereof overlap the inner ends of the divided blades 15a, 15a by a width α in the rotation locus, and the cutting widths of the cutting blades 15, 16 are the same, so that each The applied cutting loads are the same.

In FIG. 3, reference numeral 17 is a mounting hole for attaching the circular saw to a rotationally driven shaft (not shown), reference numeral 18 is a through hole through which a tightening bolt is passed, and reference numeral 19 is a hole for positioning. This is a positioning hole.

However, in the carbide circular saw with the above configuration,
Since the cutting blade tip 14 is brazed with its lower end inserted into the mounting groove 13, the brazing area of the cutting blade tip 14 can be increased by the side surface 13b. Moreover, the side surface 13b supports the cutting blade tip 14 against the cutting load acting on the cutting blades 15 and 16. Therefore, the cutting edge tip 14
It is possible to improve the brazing strength of the material and prevent it from falling off. Further, as a result, the total amount of re-grinding of the cutting blade tip 14 can be greatly increased, and the life of the circular saw can be improved, thereby reducing the total cost of the circular saw. In other words, if the initial height of the cutting tip 14 is made higher than the conventional one by the depth of the mounting groove 13, the side wall of the mounting groove 13 will increase as shown by the two-dot chain line in FIG. When re-grinding is performed until 13b disappears, the attachment state of the cutting blade tip 14 becomes similar to that of a conventional circular saw, and from this state, further re-grinding can be performed to the same degree as that of a conventional circular saw. Therefore, in this case, the amount of re-grinding can be increased by the depth of the mounting groove 13. In addition, since the amount of re-grinding can be increased, forming the mounting groove 13 and increasing the height of the cutting edge tip 14 increases the initial manufacturing cost of the circular saw, but takes into account the re-grinding. Therefore, the total cost can be reduced. Furthermore, cutting blade 1
Since the lengths 5 and 16 are approximately half of the total blade width, the cutting load acting on each cutting edge 15 and 16 can be reduced, thereby further preventing the cutting blade tip 14 from falling off. be able to.

As explained above, according to the circular saw with carbide of this invention, a mounting groove is formed on the outer periphery of the circular saw body adjacent to and in front of the back metal part, and the inner end of the cutting blade tip is mounted. Since the cutting blade tip is inserted into the groove and fixed to the circular saw body by brazing with the back side of the cutting blade in contact with the back metal part, it is possible to prevent accidents of the cutting blade tip falling off. This makes it possible to extend the life of the circular saw and reduce the total cost of the circular saw. The cutting edge of one cutting edge is formed at the center of its outer circumferential side by approximately half of the total blade width, and the cutting edge of the other cutting edge is formed so that the inner edge Since the cutting edge of the blade tip is formed at both ends so that they overlap in the rotation trajectory, the cutting load acting on each cutting edge can be reduced by approximately a quarter of the total blade width. It is possible to further prevent the blade tip from falling off.

[Brief explanation of the drawing]

Figures 1 and 2 show an example of a conventional circular saw with a carbide attachment. Figure 1 is a plan view thereof, Figure 2 is an enlarged view of the circular part in Figure 1, and Figures 3 to 7 are One embodiment of this invention is shown, FIG. 3 is a plan view thereof, FIG. 4 is a front view thereof, FIG. 5 is an enlarged view of the V-circle portion in FIG. 3, and FIG. −A enlarged cross-sectional view,
Figure 6B is an enlarged sectional view taken along the line B-B in Figure 5;
The figure is similar to FIG. 5, with the cutting tip removed from the circular saw body. 11...Circular saw body, 12...Back metal part,
12a...Wall surface, 13...Mounting groove, 13a, 1
3b... Side surface, 13c... Bottom surface, 14... Cutting blade tip, 14a... Back surface, 15, 16... Cutting blade.

Claims (1)

[Claims for Utility Model Registration] A plurality of back metal parts projecting outward in the radial direction of the circular saw main body are formed at a distance from each other in the circumferential direction on the outer periphery of the circular saw main body, and the base end of the back metal parts A mounting groove extending in the width direction of the circular saw body is formed adjacent to and in front of the section, and a cemented carbide cutting blade tip having a cutting edge at the outer peripheral end is attached to the inner peripheral end thereof. is inserted into the mounting groove, and is fixed to the circular saw body by brazing with the outer circumferential end of the back metal part in contact with a wall surface facing the rotational direction of the back metal part, and the circular saw body 2 adjacent to each other in the circumferential direction of
The cutting edge of one of the two cutting edge tips is formed at the center of the outer circumferential side of the one cutting edge tip with a length approximately half of the total blade width, and the cutting edge of the other cutting edge tip is The cutting edge of the blade tip is arranged so that the inner end thereof overlaps the end of the cutting edge formed on the one cutting edge tip at each outer circumference side end of the other cutting edge tip in a rotation trajectory. A carbide circular saw characterized by being formed with a length that is approximately a quarter of the total blade width.