BG1317U1 - Knife for rotational punching machine - Google Patents

Abstract

The knife is designed for cutting sanitary absorbents, labels, packaging blanks and other details cut in strip material on paper, textile or metal base (band). In is used to provide a constant load per unit area of ??the cutting path in the various sections along the cutting edge, consequently, even wear. The knife comprises a main cylinder (2) having cutting edge (8) with cutting path (1) of variable width along the cutting edge (8). At both ends of the cylinder (2) there are concentric boards (10). The width of the cutting path (1) along the cutting edge (8) increases in proportion with increasing the size of the angle formed between the tangent (4) to the cutting edge (8) and the generatrix (5) of the cylindrical surface of the main cylinder (2) and in the opposite direction it is decreasing.

Description

Technical field

The utility model refers to a rotary punch knife that is used in the production of sanitary absorbents, labels, blanks and other details cut from strip material on paper, polyethylene or metal backing.

BACKGROUND OF THE INVENTION

A rotary knife is known for a rotary punch, a cylindrical body with a cutting contour formed on the main cylinder, with concentric edges formed at the ends of the cylinder having radii smaller than the radius of the main cylinder. The contour is obtained by moving a trapezoidal tooth in cross section along the cylinder [1].

The load on the cutting edge in the known knife in the different sections is different and uneven wear of the cutting contour is observed along its length, which results in a reduced durability.

The technical nature of the utility model

The utility of the utility model is to create a rotary knife for a rotary die with a variable width of the cutting path along the cutting contour, so that when cutting, the specific load per unit area of the track is achieved, resulting in even wear at work and overall higher durability.

This task is accomplished with a rotary punch knife, a cylindrical body with a cutting contour formed on the main cylinder, with concentric edges formed at the edges of the cylinder with radii smaller than the radius of the main cylinder. The contour is obtained by moving a trapezoidal tooth in cross section along the cylinder. According to the utility model, a variable width cutting path is formed along the cutting contour. It is larger in sections where its contact with the smooth drum is in the vicinity of a point, i. the contact area is very small. These are the sections where the tangent to the contour makes a right angle with the cylinder forming the smooth drum (tangent to the contour including straight and curved sections) and vice versa, the path is narrower in the sections where the tangent to the contour is parallel to the forming drum. The area of the contact spot is a function of the angle of the tangent of the contour with respect to the cylinder forming.

The advantage of the utility model is that it provides a uniform load per unit area of the cutting path of the various sections along the cutting contour, hence even wear. With a constant track width, wear is greatest in the areas where contact between the cutting circuit and the cylindrical drum in the vicinity is a point (this is due to the fact that the outer diameter of the cutting circuit is located on the cylinder).

Another advantage is that in such a construction, the required cutting force that compresses the cutting blade to the smooth drum is determined based on the minimum constant cutting force required along the cutting circuit. Conversely, at a constant width of the cutting path, the force by which the cutting knife is pressed against the smooth drum is determined by the maximum force required to cut the most unfavorable section of the contour.

Explanation of the annexed figures

An exemplary embodiment of the utility model is shown in the attached figures, where:

Figure 1 is a view of a rotary punch knife;

Figure 2 - unfolding the cutting contour;

3 is a cross-sectional view of the cutting contour.

An example of a utility model

According to FIG. 1 shows a rotary punch knife. The cutting path 1 is located on a main cylinder 2 (Fig. 1) with a radius of Bright (Fig. 3). In FIG. 2 shows an expansion of the cutting contour along which a variable width cutting path is located. The width of the track b along the cutting contour 8 increases in proportion to the magnitude of the angle alpha that connects the tangent to the cutting contour with the axis 2 forming

W7 Ul new cylinder 2 and vice versa reduced. The cutting contour in cross section has the form of a trapezoidal tooth, on the top of which is a small base, which is the width of the cutting path. The blade portion of the blade is obtained as this section is "slid" along the cutting contour 8 disposed on the main cylinder. At both ends of the cylinder body of the blade 9 are located concentric beads 10 with radius R6 <RpK.

Using the utility model

During operation, the master cylinder 2 is deflected onto a smooth drum 5, thereby cutting the contour of the sanitary absorbents 7 from the multilayer strip material which is fed between the cutting blade and the smooth drum. To ensure the cutting is necessary in all sections, ie. along the entire length of the cutting path 8, RpK> R6. During operation, as a result of wear, the RpK is continuously reduced. In addition, the width of the track changes proportionally, thus increasing the cutting resistance, which is compensated by adjusting it - increasing the force of the knife pressing against the smooth drum 5.

Claims (2)

1. A rotary punch knife configured as a cylindrical body with a cutting contour formed on a main cylinder, concentric edges formed at the ends of the cylinder having radii smaller than the radius of the main cylinder, whereby the contour is obtained by displacing a trapezoidal tooth in cross section along the cylinder, characterized in that a variable width cutting path (1) is formed along the cutting contour (8). Knife according to claim 1, characterized in that the width of the path (1) along the cutting contour (8) increases in proportion to the increase in the magnitude of the angle that connects the tangent (4) to the cutting contour (8) with the forming (5) on the cylindrical surface of the master cylinder (2) and decreases in the opposite direction.