JPH0524476Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a puncher for punching holes in paper, and more specifically to a puncher installed in a peripheral device of a copying machine.

Prior Art As shown in FIGS. 4 and 5, it has a punch 2 fixed to a rotating body 1 and a die 5 made of a rotating body 3 with a hole 4 formed in its outer periphery, and the punch and die are connected to each other. A puncher is known that rotates synchronously to fit the tip of the punch into the hole of the die. A modification of the die shown in FIG. 6 is also known.

In the conventional puncher, considering the outer diameter of the die 5 and the distance between the tip of the punch 2, that is, the cutting edge, from the center of the rotating body, the cutting edge of the punch 2 is The cutting edge angle α between the paper surface and the paper surface when the punch starts to fit into the hole 4 of the die 5 is determined by the larger the outer diameter of the die 5, and the larger the distance of the cutting edge of the punch 2 from the center of the rotating body. As the diameter of the die 5 decreases, the cutting edge angle α becomes smaller as shown in FIG. 7A, and conversely, as the diameter of the die 5 becomes smaller, the cutting edge angle α becomes larger as shown in FIG. 7B.

The paper 6 is sheared when the punch 2 fits into the hole 4, but when the cutting edge angle α is small as shown in Fig. 7A, the paper is reliably punched by the punch and the hole, whereas in Fig. 7B. If the cutting edge angle α is large, the paper will escape to the punch side at the beginning of cutting, as shown by the broken line in Figure 7B, and the paper will not be cut properly by the punch and the hole, causing the paper in the area of the cut hole to Some parts may remain attached without being cut. For this reason, in conventional punchers, in order to make good holes without causing burrs or cutting errors in the cut section, the diameter of the die must be made large, and the center of rotation of the cutting blade of the punch must be There was a problem in that the distance between the two had to be increased. For this reason, the puncher becomes large as a whole, making it difficult to incorporate it into a compact machine.

Purpose The purpose of the present invention is to solve the above-mentioned conventional problems and provide a puncher that can reliably punch holes using a die with a small diameter.

Configuration In order to achieve the above-mentioned purpose, the present invention has the following objectives: the distance from the rotation center of the outer periphery of the rotating body forming the die
At least in the range of the hole formed in the die, the punch gradually increases in size from the position where the punch begins to fit into the hole to the position where the punch ends.

The structure and operation of the present invention will be explained in detail based on the embodiment shown in the drawings.

In FIG. 1, the structure in which the punch 2 is fixed to the rotating body 1 is the same as the conventional one.
The die 5 is different from the conventional one in the shape of the outer periphery of the rotating body 3 having the hole 4. That is, from the position where the hole 4 starts contacting the cutting edge portion of the punch 2, that is, the distance r ₁ from the rotation center of the position 4a where the punch 2 starts to fit into the hole 4, to the position of the hole 4 where the punch 2 ends fitting. 4b is formed so that the distance from the rotation center gradually increases up to a distance r ₂ from the rotation center. That is, at least in the range of the hole 4, the radius of the outer periphery of the rotating body 3 is formed to gradually increase from the upstream side to the downstream side in the rotation direction. The overall shape of the rotating body 3 of the die 5 of the present invention is as follows:
Both the conventional shape shown in FIG. 5 and the conventional shape shown in FIG. 6 can be applied.

When forming the outer periphery of the rotating body 3 as described above, simply form the rotating body 3 along a straight line connecting the position 4b of the hole 4 of the rotating body with radius r ₂ and the position _4a of the hole 4 with radius r 1. It can be formed by cutting the outer periphery of the cylinder diagonally along a plane.

It has been found that it is best to set the difference between the radii r ₂ and r ₁ , that is, the machining allowance, to an amount close to S/2 of the maximum penetration amount S of the punch into the die in the rotating body before cutting. In contrast to the example of FIG. 1 in which the outer circumferential portion of the rotating body 3 is cut along a plane, as shown in FIG.
It can also be formed by eccentrically machining the outer circumference of the rotating body 3 with a curve having a radius R that connects the starting point 4a and the ending point 4b and centers on the point O.

While FIGS. 1 and 2 are examples of having one hole, a plurality of holes, for example two, can be formed as shown in FIG. 3.

In the conventional method, when looking at the beginning of cutting the paper when the length of the punch is shortened to about 1/2 compared to the example shown in Fig. 4, the cutting edge angle becomes α _{1 as shown in Fig. 8, and the cutting edge angle becomes α 1} . 4
The angle is larger than the cutting edge angle α in the case shown in the figure. With such a large cutting edge angle, mistakes may occur in drilling as described above. However, in the puncher according to the present invention, when a punch of the same length as the example shown in Fig. 8 is used, the cutting edge angle is α ₂ as shown in Fig. 9.
The cutting edge angle is approximately the same as shown in FIG. In the conventional case in Fig. 1, the punch 2 is inserted into the hole 4 at A.
This is because insertion starts at a point B, whereas in the present invention it can be moved closer to a line connecting point B and the center of rotation of the punch and die. Specifically, while the diameter of the locus of the cutting edge of the punch in Fig. 4 is 50 mm, in Fig. 9 the diameter is selected to be about 22 mm and the cutting edge angle α can be made almost the same. From this, it has become clear that the punch and die according to the present invention can be formed as a rotating body with a diameter approximately half that of the conventional punch and die. If the punch and die can be made smaller, it has become possible to incorporate them into machines that are about half the size of conventional machines.

Although the above explanation has mainly focused on the die, it is possible to perform the same process on the punch as well.

Effects According to the present invention, at least the outer diameter of the die can be made small, making it possible to make the puncher more compact as a whole, and moreover, it is possible to exhibit hole punching performance equivalent to that of conventional large-diameter dies.

This invention eliminates the occurrence of burrs and uncut parts at the beginning of hole cutting.

[Brief explanation of the drawing]

1 is a front sectional view of a puncher according to the present invention, FIG. 2 is a sectional view of a modification of the die shown in FIG. 1, FIG. 3 is a sectional view of a modification of the die of FIG.
The figure is a front sectional view of a conventional puncher, Figure 5 is a perspective view, Figure 6 is a perspective view of a modified example, Figure 7 is an explanatory diagram showing the relationship between the punch cutting edge angle and paper, and A is a cutting edge. When the angle is small, B shows the case where the cutting edge angle is large, FIG. 8 is a front cross-sectional view of the operation of a conventional short punch, and FIG. 9 is a puncher according to the present invention corresponding to FIG. 8. FIG. 1...Rotating body, 2...Punch, 3...Rotating body,
4...Hole, 5...Die, 4a...Start point (position to start fitting), 4b...End point (position to finish fitting).

Claims (1)

[Scope of utility model registration request] It has a punch fixed to a rotating body and a die made of the rotating body with a hole formed in its outer periphery, and the punch and die are rotated synchronously to fit the tip of the punch into the hole of the die. In the puncher, the distance from the center of the outer periphery of the rotating body forming the die gradually increases from the position where the punch starts to fit into the hole to the position where the punch ends.