JPS59161224A - Cutter forming method of saw chain - Google Patents

Abstract

PURPOSE:To easily form a chisel blade and a semi-chisel blade of a cutter with higher strength by providing a process wherein a upper blade is melted down into a prescribed thickness as well as a side surface part reaching a lateral blade is forlded, a process wherein the upper blade is folded at a prescribed angle, and a process wherein R of the lateral blade part is melted down. CONSTITUTION:Upon forming a chisel blade or a semi-chisel blade being a cutter for one parts of a saw chain, a raw material 9 of a metallic material is firstly placed on a disc 10a, and a side surface part 12 connecting from a cutter link 11 to a lateral blade 4 is folded at an angle of approximately 40 deg.-50 deg. due to the lowering movement of a punch, while a part forming a upper blade 3 is melted down into a tapered shape. Then, a portion of the upper blade 3 is folded so as to make an angle ranging approximately 85 deg.-87 deg. with respect to the cutter link 11 by holding the raw material 9 (cutter link 11) between the disc 10b and a stripper 14 and allowing a bend top 15 to be lowered. Thereafter, by holding the cutter link 11 between the dice 10c and the stripper 14, and allowing a punch 13b to be elevated, the formation is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a chisel blade or semi-chisel blade of a saw chain cutter.

The cutter 2 of the conventional saw chain 1 shown in Fig. 1 has a sharp corner 5 connecting the upper blade 3 and the side blade 4 as shown in Fig. 2, and is called a chisel blade 6, as shown in Fig. 3. As shown, the corner 5 is approximately 70 mm thicker than the thickness of the upper blade 3 and the side blade 4 before and after forming the corner 5.
% or less is generally called a semi-chisel blade 7. That is, normally, the corner portion 5 cannot be reduced to less than 75 inches in thickness by cold bending alone. Even if the horizontal blade 4 is crushed and the meat is gathered in the corner, the horizontal blade 4 becomes thinner and there is a problem in terms of strength. Therefore, in order to obtain the chisel blade 6 and the semi-chisel blade 7, the rounded corner 5 is first formed and then the corner 5 is cut by machining, or the corner 5 is formed as shown in FIG. In the present invention, the coining operation is a method in which one step is added between the first step and the second step so as to generate the rib-like thick portion 8 in advance at the planned portion.

The method of machining is time-consuming and cannot be said to be an appropriate method. In addition, the method of adding one coining operation does not only increase the number of steps by one, but also causes the fibers of the material to be subjected to compressive force due to the coining operation, causing them to wave significantly, and then due to the bending operation, they are then subjected to tensile force. At this point, the fibers are broken in some places.Furthermore, in the final step, when the horizontal blade 4 crushes the fibers, the outer surface of the corner 5 is completely separated, and the fibers are weak in terms of strength. It is lower than when they are connected, and this is taken into consideration in advance during coining operations.
The inner thickness portion 8 must be increased, which is a troublesome process.

An object of the present invention is to provide a chisel blade 6 and a semi-chisel blade 7 that can be easily molded without the drawbacks of the prior art described above and have high strength.

The present invention anticipates the wall thickness that is expected to decrease in advance,
By increasing the thickness of the material 9 accordingly, the cutter 2 with high strength can be obtained using a simple molding method.

The present invention will be described below with reference to FIGS. 5 and 6 showing one embodiment thereof.
This will be explained in detail based on FIG. In FIG. 6, a metal material material 9 is placed on a die 10a, and the side surface 12 connected to the side blade 4 from the cutter link 11 is bent at an angle of 40 to 50 degrees, and at the same time, the portion forming the upper blade 3 is tapered. Punch the process of crushing into shape at the same time 13. This is done by moving in the direction of the arrow.

Figure 6 shows the next process, dies 10b1 stripper 1.
4, and by moving the bending piece 15 in the direction of the arrow, the upper blade 3 portion is bent at an angle of 85° to 87° with the cutter link 11. At this time,
The corner 5 connecting the upper blade 3 and the horizontal blade 4 is approximately 75 mm thick of the horizontal blade 4.
% of R is formed.

FIG. 7 shows the final process, in which the cutter link 11 is connected to the die 1.
0. and the stripper 14, and the end surface 16 of the upper blade 3
The cutter 2 is struck by the stripper 14, and with no escape of the upper blade 3, the cutter 2 is punched into the punch 13b so that the corner 5 of the cutter 2 has the desired radius, even if there is almost no radius. By providing a similar radius and moving the punch 13b in the direction of the arrow, the side blade 4 portion is crushed and gathered at the corner 5 due to the reduced plate thickness, forming a predetermined radius.

The plate thickness ratio between the drive link 18 and the cutter 2 of the conventional saw chain 1 shown in FIG. 1 is approximately 10 to 30% thicker in the drive link 18. Therefore, as shown in FIG. 8, the cutter 2 is provided on the drive link 18 and sandwiched between the tie straps 19. By doing this, the thickness of the cutting blade 20 is increased.
Naturally, the present invention can be accomplished without increasing the thickness of the cutter 2.

As described below, according to the present invention, the thickness of the side blade part, which is expected to decrease in advance, is covered by the thickness of the material, and there is no need for coining operations, so the strength is improved. Chisel blades and semi-chisel blades can be obtained easily and at high cost.

[Brief explanation of the drawing]

Figure 1 is a partially omitted side view showing a conventional saw chain;
Figure 1. Fig. 3 is a front view schematically showing the shape of a chisel blade and semi-chisel blade, Fig. 4 is a partially omitted front view showing a conventional coining operation, and Figs. 5, 6, and 7 are according to the present invention. 8 is a partially omitted side view, and FIG. 8 is a side view in which the invention is applied to a saw chain of a new shape. In the figure, 2 is the cutter, 3 is the upper blade, 4 is the side blade, 5 is the corner, 9 is the material, 10a, 10'b + 10c is the die, 11 is the cutter link, 12 is the side part, '3a +
13b is a punch, 14 is a stripper, and 15 is a bending piece.

Claims (1)

[Claims] A chisel blade or a semi-chisel blade in which the radius of the corner connecting the upper blade and the side blade is 70 inches or less than the plate thickness before and after the corner in a one-part saw chain cutter. A first step in which the process of crushing the blade to a predetermined thickness and the bending process of bending the side part from the cutter link to the side blade with an inclination of 40 to 50' are performed simultaneously;
f, bend to 85 to 87 degrees for one cutter link,
A second step in which the portion where the horizontal blade is formed in the bending process has a large radius, and the radius of the horizontal blade portion is further crushed, and the radius at the corner is determined only by the radius previously set on the punch. A method for forming a saw chain cutter, characterized in that the thickness of the side blade is reduced by 30 to 50% relative to the thickness of the cutter link, that is, the thickness of the material.