EP0670203A1 - Method and device for cutting paper sheets assembled in a ream - Google Patents

Abstract

The paper cutting procedure consists of driving the blade (1) through the stack (2) in a direction parallel to the plane of the sheets, with the blade shaped to make a cut in sequence from the upper to the lower sheets. The blade is in the form of a toothed plate (4, 5) in the shape of a triangle with sides of unequal length, having its longer side at an angle to the direction of relative movement between the blade and paper stack and carrying the teeth, which have edges of different lengths. In a variant of the design, the blade can incorporate an additional section, similar to the first and facing in the opposite direction. The additional blade section can be made in one piece with the main blade, and the blade teeth can be detachable.

Description

Technical field

The invention belongs to the graphics industry. It relates in particular to a method for cutting collated paper sheets and to an apparatus for carrying it out.

Conventional procedure

Graphic engineering, which produces automated production lines that also include the processing of book blocks, is currently in a development stage in which cutting the book blocks is the bottleneck; both in terms of improving the quality of the cutting of the book blocks and in terms of increasing the performance of the entire production line.

At present, a conventional cutting method is mostly used for cutting a paper stack, in which the knife penetrates into the paper stack and divides it in the direction transverse to the plane of the sheet, the knife and the paper stack being moved relative to one another.

For the implementation of this known method for cutting pieces of paper, a device with a knife in the form of a circular saw blade with teeth is used which has cutting edges and which is rotatably mounted on a substructure and is provided with a drive for the relative movement between the knife and the paper stack.

The disadvantage of this method for cutting paper stacks is the low cut quality on the end faces of the paper stacks, since the teeth of the knife inevitably leave visible traces on the surface of the end face of the processed paper stack when it penetrates into the paper stack and when it is divided. The cutting depth of each tooth is limited by its size, which in turn limits the speed of the relative movement of the paper stack to the knife and accordingly the performance of the device. The desire to increase the performance of the device requires increasing the speed of rotation of the knife; this in turn leads to an increase in the noise level due to violent vibrations of the paper sheets in the stack, since the knife moves across the paper sheets. But mostly this device is the most important source of noise among all devices that are used, for example, in the processing of book blocks.

The present invention has for its object to provide a cutting method for collated sheets of paper and a device for its implementation, such that when the knife penetrates into the paper stack and when it is divided, there are no cutting marks on the surfaces of the end faces of the trimmed paper stack and an increase in relative speed of the paper stack to the knife is possible and that vibrations of the sheets of paper are excluded during cutting. This is intended to increase the quality of the end faces of the paper stack to be processed and the performance, and to reduce the noise during the cutting process.

The essence of the invention is that the cutting method for collated paper sheets provides that the penetration of the knife into the paper stack and its division is carried out according to the invention parallel to the collated paper sheets with relative movement of the knife and the paper stack.

The penetration of the knife into the paper stack and its division with a relative movement of the knife and the paper stack in a direction parallel to the sheets prevents visible traces of the cutting edges of the knife on the processing end faces of the paper stack. This is because of such a relative movement Always cut a certain number of sheets from start to finish between the knife and the stack of paper without touching other sheets.

The quality of the trimmed end faces of the paper stack is further improved in that each point of the cutting edges of the knife moves parallel to the sheet as it penetrates into the paper stack and its division, and thus leaves no visible traces of the cutting tool.

The efficiency of cutting the paper stack increases because the speed of the knife penetrating and dividing the paper stack does not depend on the depth of the cut, which depends on the size of the tooth, and not on the rotational speed of the knife, which increases the noise level increased, limited. In addition, the noise level is reduced since there are no vibrations of the paper sheets which accompany the conventional cutting of the sheets in the paper stack with the knife movement oriented transversely to the paper sheets.

The penetration of the knife into the paper stack is preferably carried out on the part of the top and bottom sheets.

The quality of the trimmed paper stack increases because of an improvement in the cut quality of the sole, which consists of a few last sheets, which receive better grip when the knife penetrates from the top and bottom sheets, do not bend and therefore improve the cutting condition of the sole.

The knife can be inserted into the paper stack one after the other, first from the top sheet of the paper stack and then from the bottom sheet.

This reduces the cutting quality, since the condition of the knife penetrating into the paper stack and its division is compensated for all sheets; all bows have a firm hold when divided.

The present object can be achieved with a device for carrying out the method for cutting collated sheets with a knife, which in the form of a plate with teeth,
which have cutting edges, executed and mounted on a substructure and with a drive for a relative movement of the knife and the paper stack.

According to the invention, the plate has the shape of an isosceles triangle, the longer side being at an acute angle to the relative direction of movement of the knife and the paper stack. The teeth are on the longer side of the plate and are made with two sides of different lengths. The cutting edges are on the longer sides.

Such a design of the device increases the quality and the performance and ensures a reduction in the noise level.

The design of the plate of the knife in the form of an isosceles triangle, the longer side of which is at an acute angle to the direction of movement of the knife and the stack of paper, results in a reduction in the cutting force; therefore the relative speed of the knife and the stack of paper can be increased. In this case, each tooth of the knife cuts part of the paper stack from start to finish, which consists of a few sheets, which prevents traces of the knife on the trimmed surface of the paper stack - a reliable and trouble-free way of cutting.

The quality of the trimmed surface of the paper stack increases because every point of the cutting edge of the knife, including the tips of the teeth, moves parallel to the paper sheets when penetrating into the paper stack and dividing it, and therefore does not cross with the sheets also leaves no visible traces.

The noise level is significantly reduced, since the proposed construction of the knife ensures a uniform penetration of the knife into the paper stack, that is to say causes a cut of the paper stack in which each tooth from the beginning to the end a certain part of the paper stack, which consists of a few Arch exists, cuts, but there is no violent oscillation of the arches that accompany the traditional cutting method.

This device preferably also has an additional knife, similar to the main knife, which is mounted on the substructure and is located in the plane of the main knife. The teeth of this additional knife would be aligned symmetrically to the teeth of the main knife and shifted from one another.

This additional knife ensures better cutting quality by making it easier to cut the sole (if there are only a few sheets left to cut, the strength of the paper stack is reduced, which makes cutting the sole more difficult).

You can run this additional knife together with the main knife.

In such a case, the need for an adjustment of the additional knife in the plane of the main knife and other adjustments when mounting the additional knife become obsolete.

Furthermore, the teeth can also be designed individually and mounted on a plate with the possibility of changing their position for the alignment of the cutting edges of the teeth in one plane.

In such a case, the operating conditions of the device improve by reducing the amount of work involved in sharpening the knife, since sharpening is made much easier.

The knife is preferably designed such that the tips of the cutting edges of the teeth on a section whose length is 1/3 to 1/4 of the total length of the longer side of the knife adjoins the shorter side of the knife, on a line with less Angle to the relative direction of movement of the knife and the paper stack than the angle of the remaining section of the longer side of the knife.

In this case, the cutting quality increases due to an improvement in the cutting conditions for the lower sheets, since the cutting force is reduced by a smaller angle of the line of the tooth tips of the knife to the direction of movement of the knife and the paper stack.

In this case, the knife can be designed as two connected plates, the connecting line of which passes between the sections of the longer side of the knife plate.

Such a design facilitates the production and sharpening of the knife.

Furthermore, the device could be designed with two brackets, which are mounted on the base. The knife with the possibility of suspension is mounted on a holder and resiliently against the second holder by means of a spring. It is expedient here that this device is equipped with a stop for limiting the suspension angle, which is attached to the substructure.

In such a case, the life of the knife is increased by reducing the regrinding. Since the cutting force increases when the tooth tips become blunt, pressure is created and the knife is twisted or the blunt cutting edges are twisted off into the non-working zone. Sharper zones of the cutting edge now act as tips of the cutting edges. This brings about a restoration of the operability of the device.

It can be recommended to install a means for regulating the pressure force of the spring in the form of a screw, which is attached to the holder against which the knife springs.

Such a means ensures a nominal angle of the knife to the direction of the relative movement of the paper stack and the knife, and thus ensures nominal conditions of the cutting force, which changes when processing paper stacks of different heights and types of paper.

It is recommended to mount two parallel plates on both sides of the base in the plane of the knife, which ensure the direction of movement of the knife during springing in one plane, but do not prevent the movement of the paper stack.

Brief description of the drawings

Fig. 1

eine schematische Darstellung des erfindungsgemässen Verfahrens zum Schneiden zusammengetragener Papierbogen;

Fig. 2

das Verfahren zum Schneiden zusammengetragener Papierbogen durch Eindringen des Messers von Seiten der obersten und untersten Bogen;

Fig. 3

eine Gesamtansicht der erfindungsgemässen Vorrichtung zum Schneiden zusammengetragener Papierbogen, wobei sich der Papierstapel bewegt und das Messer still steht;

Fig. 4

Schnitt IV-IV in Fig. 3;

Fig. 5

die Geometrie des erfindungsgemässen Messers zum Schneiden zusammengetragener Papierbogen in vergrössertem Massstab;

Fig. 6

Schnitt VI-VI in Fig. 5;

Fig. 7

eine Gesamtansicht der Vorrichtung zum Schneiden zusammengetragener Papierbogen während des Eindringens des Messers in den Papierstapel von Seiten der obersten und untersten Bogen;

Fig. 8

Schnitt VII-VII in Fig. 7;

Fig. 9

eine Variante der Vorrichtung zum Schneiden zusammengetragener Papierbogen mit einem Zusatzmesser, welches gemeinsam mit dem Hauptmesser ausgeführt wurde;

Fig. 10

Schnitt X-X in Fig. 9;

Fig. 11

die Geometrie des erfindungsgemässen Zusatzmessers, welches gemeinsam mit dem Hauptmesser ausgeführt ist;

Fig. 12

Schnitt XII-XII in Fig. 11;

Fig. 13

eine Variante der Vorrichtung für das Schneiden zusammengetragener Papierbogen im Falle montierbarer Zähne des Messers;

Fig. 14

Schnitt XIV-XIV in Fig. 13;

Fig. 15

die Geometrie des erfindungsgemässen Messers mit montierbaren Zähnen in vergrössertem Massstab;

Fig. 16

Schnitt XVI-XVI in Fig. 15;

Fig. 17

eine Variante der erfindungsgemässen Vorrichtung zum Schneiden zusammengetragener Papierbogen mit einem Messer, mit verschiedenen Neigungswinkeln der Abschnitte der Linie der Zahnspitzen zur relativen Bewegungsrichtung des Messers und des Papierstapels;

Fig. 18

Schnitt XVII-XVII in Fig. 17;

Fig. 19

ein erfindungsgemässes Messer ausgeführt aus zwei verbundenen Platten in vergrössertem Massstab;

Fig. 20

Schnitt XX-XX in Fig. 19;

Fig. 21

eine Variante der erfindungsgemässen Vorrichtung zum Schneiden von Papier mit einem federnden Messer;

Fig. 22

Schnitt XXII-XXII in Fig. 21.

The present invention is described in more detail below using a specific exemplary embodiment with references to the accompanying drawings. Show it:

Fig. 1

is a schematic representation of the inventive method for cutting collated paper sheets;

Fig. 2

the method of cutting collated sheets of paper by penetrating the knife from the top and bottom sheets;

Fig. 3

an overall view of the inventive device for cutting collated sheets of paper, with the stack of paper moving and the knife stationary;

Fig. 4

Section IV-IV in Fig. 3;

Fig. 5

the geometry of the knife according to the invention for cutting collated paper sheets on an enlarged scale;

Fig. 6

Section VI-VI in Fig. 5;

Fig. 7

an overall view of the device for cutting collated paper sheets during the penetration of the knife into the paper stack from the top and bottom sheets;

Fig. 8

Section VII-VII in Fig. 7;

Fig. 9

a variant of the device for cutting collated paper sheets with an additional knife, which was carried out together with the main knife;

Fig. 10

Section XX in Fig. 9;

Fig. 11

the geometry of the additional knife according to the invention, which is designed together with the main knife;

Fig. 12

Section XII-XII in Fig. 11;

Fig. 13

a variant of the device for cutting collated paper sheets in the case of mountable teeth of the knife;

Fig. 14

Section XIV-XIV in Fig. 13;

Fig. 15

the geometry of the knife according to the invention with mountable teeth on an enlarged scale;

Fig. 16

Section XVI-XVI in Fig. 15;

Fig. 17

a variant of the inventive device for cutting collated paper sheets with a knife, with different angles of inclination of the sections of the line of the tooth tips to the relative direction of movement of the knife and the paper stack;

Fig. 18

Section XVII-XVII in Fig. 17;

Fig. 19

a knife according to the invention made of two connected plates on an enlarged scale;

Fig. 20

Section XX-XX in Fig. 19;

Fig. 21

a variant of the inventive device for cutting paper with a resilient knife;

Fig. 22

Section XXII-XXII in Fig. 21.

Best implementation variant of the invention

The cutting method to be patented for collated sheets of paper provides for the knife 1 (FIG. 1) to penetrate into the paper stack 2 and cut it up. A movement (arrow A) of the knife 1 or a movement (arrow B) of the paper stack 2 or of the knife 1 and the paper stack 2 relative to one another is realized.

According to the invention, the penetration of the knife 1 into the paper stack 2 and the division of the paper stack 2 in the directions of the two arrows A and B is carried out parallel to the sheets of the paper stack.

The penetration of the knife 1 in the direction of arrows A and B, as can be seen from FIG. 2, into the paper stack 2 is carried out simultaneously on the part of the upper sheets of the paper stack 2 and the lower sheets of the paper stack 2.

This allows the quality of the surface of the cut part of the paper stack to be increased by improved cutting conditions of the sole.

The penetration of the knife 1 into the paper stack 2 can be carried out as follows: first from the side of the upper sheets of the paper stack 2, then from the side of the lower sheets of the paper stack 2.

The proposed cutting method for paper stacks is carried out by means of a device consisting of a base 3 (FIG. 3) on which the knife 1 (FIG. 4) in the form of a plate 4 with teeth 5, which have cutting edges 6 (FIG. 5) carried out. The plate 4 has the shape of an isosceles triangle, where the longest of the sides 7 is at an acute angle α (FIG. 3) to the relative direction of movement of the knife 1 and the paper stack 2. The teeth 5 are located on this longest side 7 of the plate 4 (FIG. 5) and are designed with two sides 8 and 9 of different lengths, the cutting edges 6 (FIGS. 5 and 6) being on the longer side 8 of the teeth 5 are located and have a radius R.

Furthermore, the device is equipped with guide elements 10 (FIGS. 3 and 4) mounted on the substructure 3, a carriage 11 placed on the guide elements for receiving the paper stack 2, equipped with pliers 12 for clamping the paper stack 2, and a drive 13 for the relative movement of the Knife 1 and the paper stack 2, which, as can be seen in FIG. 3, is connected to the carriage 11 for its possibility of transportation.

The drive 13 can be connected to the knife 1 or to the carriage 11, on which the paper stack 2 is located and the knife 1, with the possibility of the movement of the knife 1 or the movement of the carriage 1 with the paper stack 2 to one another.

Because the cutting edges of the teeth move parallel to the paper sheets and leave no visible traces, such a device guarantees and allows a better quality of the trimmed surfaces of the paper stack, an increase in the productivity of the cutting and a reduction in the noise level.

Another embodiment variant of the device for cutting a paper stack has a further knife 14 (FIGS. 7, 8) which is similar to the main knife 1 and which is mounted on the substructure and is located in one plane with the main knife 1. The teeth 15 (FIG. 7) of the additional knife 14 are arranged symmetrically to the teeth 5 of the main knife 1 and are displaced from one another. This improves the quality of the trimmed surface of the paper stack by making it easier to cut the sole of the paper stack.

9 and 10, a device with the additional knife 14 is shown, which is carried out together with the main knife 1 in one. 11 and 12, the additional knife 14 is shown on an enlarged scale, which is designed in one with the main knife 1. Such a design reduces the number of parts and in this case no additional fastening or additional regulation of the additional knife is required.

13 and 14 show a further embodiment variant of the device for cutting a paper stack. The knife 1 (Fig. 13) is designed with teeth 5 (Fig. 14) which are detachable and with the possibility of a change in position mounted on the plate 4 around the cutting edges (Fig. 15) of the teeth (Fig. 16) in one plane bring. This improves the operation of the device by reducing the work involved in grinding the knife, since all cutting edges are aligned like a cutting edge during the grinding process and the tips of the cutting edges of each tooth are reworked.

The device for cutting a stack of paper, which is shown in FIGS. 17 and 18, consists of the knife 1, where the tips 16 (FIG. 17) of the cutting edges 6 of the teeth 5 lie on the section 17, which has a length of approximately Has 1/3 to 1/4 of the total length of the longest sides 7 of the knife 1 and adjoins the shortest side 18 of the knife 1 (FIG. 18), on a line which has a smaller angle β to the relative direction of movement of the knife 1 and of the paper stack 2 has, as the angle γ of the remaining section 19 of the longest side 7 of the knife 1. The cutting quality is improved by the better cutting conditions of the lower sides of the paper stack.

19 and 20, the device for cutting a stack of paper is shown, which has a knife 1 made of two connected plates 20, 21. The plates are mounted on the knife holder 22, the connecting line 23 (FIG. 19) crossing the sections 17 and 19 of the longest side 7 of the knife 1. In this case, the manufacture and grinding of the knife 1 is simplified.

The device for cutting a stack of paper, which is shown in FIG. 21, has two holders 24 and 25, which are mounted on the substructure 3 (FIG. 22). On the holder 24 (FIG. 21), the knife 1 is mounted such that it can vibrate and is resiliently supported against the other holder 25 by means of the spring 26. The device also has a stop 27 mounted on the substructure 3 for limiting the suspension angle of the knife 1.

In this case, the life of the knife is increased by reducing the regrinding of the cutting edges of the teeth. As the tips of the cutting edges of the knife teeth oriented towards the cutting surface become blunt, the cutting pressure increases, which leads to compression of the spring and to a rotation of the knife in the direction of the paper stack or to the blunt cutting edges of the knife teeth turning away into a non-working zone, with sharper zones of the Cutting edges become tips, which restores the working ability of the device; this increases the life and productivity.

The spring 25 has a means for regulating the spring pressure, which is designed in the form of a screw 28 (FIG. 22) and is mounted on the holder 25, against which the knife 1 springs.

This gives the possibility to regulate the spring pressure and therefore also the position of the knife depending on the cutting force, which changes when cutting different types of paper and many other factors.

On the base 3 (FIG. 21), two parallel plates 29 (FIG. 22) are mounted on both sides of the plane of the knife 1, which ensure the direction of movement of the knife 1 with its springs.

In this case, the stability of the knife increases when cutting a stack of paper.

Cutting sheets gathered into a stack, e.g. Paper is carried out as follows.

With a relative movement of the paper stack 2 (FIGS. 3 and 4) and the knife 1, for example when the carriage 11 is moving with the paper stack 2 clamped in the pliers 12 along the guide elements 10 connected to the base in the direction of the knife mounted on the base 1 with teeth 5, which have cutting edges 6, the knife 1 penetrates parallel to the paper sheet into the paper stack 2 and divides it, each tooth 5 of the knife 1 from the beginning to the end cuts a part of the stack consisting of a specific number of sheets.

The device with additional knife works as follows.

With a relative movement of the paper stack 2, the main and the additional knife 1 and 14, which teeth, corresponding to 5 and 15, have, e.g. when the carriage 11 moves with the paper stack 2 clamped in the pliers 12 along the guide elements 10 connected to the substructure in the direction of the main and auxiliary knives 1 and 14 mounted on the substructure 3, the main knife 1 penetrates into the paper stack 2 parallel to the paper sheets from the side of the upper sheet and cuts the paper stack, the additional knife 14 penetrating parallel to the paper sheet from the side of the lower sheet into the paper stack 2, making an incision in the paper stack 2 from the side of the lower sheet and thus cutting the sole of the paper stack simplified.

The device with an additional knife, which is designed in one with the main knife, works as follows.

With a relative movement of the paper stack 2 (Fig. 9, 10) and the knife 1, which has teeth 5, e.g. when the carriage 11 moves with the paper stack 3 clamped in the pliers 12 along the guide elements 10 connected to the base 3 in the direction of the knives 1 and 14 mounted on the base 3, the knives 1 and 14 penetrate parallel to the paper sheets of the paper stack 3 from sides of the upper and lower sheets in the paper stack 2 and divide the paper stack.

The device for cutting a stack of paper with a knife with removable teeth works as follows.

With a relative movement of the paper stack 2 (FIGS. 13 and 14) and the knife 1 with removable individual teeth, for example when the carriage 11 is moving with the clamped in the pliers 12 Paper burst 2 along the guide elements 10 connected to the base 3 in the direction of the knife 1 mounted on the base 3 with removable teeth, the knife 1 penetrates parallel to the paper sheets into the paper stack 2 and divides the stack.

The knife 1 represents a plate 4 with removable teeth 5 (FIGS. 15 and 16) which are mounted on the plate 4 in order to change their position and thus align the cutting edges 6 of the teeth 5 in one plane. This allows the cutting edges 6 of the teeth 5 to be aligned like a cutting edge during grinding and the radius R of the cutting edge 6 of each tooth 5 to be reworked.

The device for cutting a paper stack with different angles β, γ of the sections 17 and 19 of the side 7 of the knife 1 functions as follows.

With a relative movement of the paper stack 2 (Figs. 17 and 18) and the toothed knife 1, e.g. When the carriage 11 moves with the paper stack 2 clamped in the pliers 12 along the guide elements 10 connected to the base 3 in the direction of the knife 1 mounted on the base 3, the knife 1 penetrates into the paper stack 2 parallel to the paper sheets. Each tooth 5 of the knife 1 on the section z (FIG. 19) cuts from the beginning to the end of the stack with the height h, each tooth of the second part of the knife - on the section z1 - a part of the stack 2 with a lower height h1. The knife 1 can be in the form of a plate 4 or two connected plates 20 and 21, which are mounted on the knife holder 22 and whose connecting line 23 passes through the two sections of the longest side 7 of the knife 1 (FIGS. 19 and 20) his.

The device for cutting a stack of paper with the knife, which swings on one holder and springs against the other holder, functions as follows.

With a relative movement of the paper stack 2 (FIGS. 21 and 22) and the knife 1 with teeth 5, for example, when the carriage 11 is moving with the paper stack 2 clamped in the pliers 12 along the guide elements 10 connected to the substructure in the direction of the substructure 3 by means of a knife 1 mounted by means of a holder 24, the knife 1 penetrates parallel to the paper sheets into the paper stack 2 and divides the paper stack 2.

When the tips of the cutting edges 6 of the teeth 5 of the knife 1 rounded off with the radius R on the cutting surface become blunt, the cutting pressure increases, this leads to the compression of the spring 26, which is located on the spring pressure regulating screw 28, which holds the holder 25 and the projection 30 of the knife 1 connects, for a rotation of the knife 1 in the direction of the paper stack 2 and for a turning away of the blunted cutting edges 6 of the teeth 5 of the knife 1 into a non-working zone, other sharper sections becoming tips of the cutting edges 6. Two parallel plates 29 limit the movement of the knife 1 in the plane where there is no cutting, and the stop 27 fixes the new position of the knife 1.

The proposed cutting method for paper sheets, which are brought together to form a stack and the device for carrying them out to improve the quality of the paper stack to be processed, allow the paper stack to be cut in motion, for example, book blocks at a speed of 0.5-1 m / Sec and faster, this significantly increases the productivity of the cutting machine, simplifies it considerably, reduces the noise level when performing the technological operation of cutting in motion using a knife with teeth.

The device for carrying out the proposed cutting processes for paper stacks is suitable for installing them in automatic lines for processing book blocks and in book production lines. This gives a leap in the development of cutting equipment and raises the bookbindery to a qualitatively new level.

The variants of the device for carrying out the proposed cutting method described above do not limit the scope of the invention, since the new cutting method of paper stacks opens up a wide field of application and there are development possibilities for a wide variety of equipment for cutting sheets from non-metallic material.

Application in industry

The most successful would be to use the present invention for cutting sheets of paper gathered in book block.

However, the invention can also be used for cutting sheets of non-metallic material.

Claims (12)

Method for cutting a stack (2) of paper sheets gathered, the knife (1) penetrating into the paper stack (2) and dividing it by a relative movement between the knife (1) and the paper stack (2), characterized in that the penetration of the Knife (1) in the paper stack (2) and its division takes place in a direction parallel to the paper sheets brought together to form a stack (2). A method according to claim 1, characterized in that the penetration of the knife (1) in the paper stack (2) takes place simultaneously from the side of the upper sheet and the lower sheet of the stack (2). A method according to claim 1, characterized in that the penetration of the knife (1) into the paper stack (2) in the order: First from the side of the upper sheet of the stack (2) and then from the lower sheet of the stack (2) . Device for carrying out the method according to claim 1, with a knife (1) mounted on a substructure (3) in the form of a plate (4) with teeth (5) which have cutting edges (6) and with a drive (13) for one relative movement of the knife (1) and the paper stack (2), characterized in that the plate (4) has the shape of an isosceles triangle, the longest side (7) being at an acute angle (α) to the relative direction of movement of the knife ( 1) and the paper stack (2) that the teeth (5) are arranged on this longest side (7) of the plate (4) and are of two different lengths (8, 9) and that the cutting edges of the teeth are on one another the longer of the sides (8). Device according to claim 4, characterized in that it additionally has an additional knife (14) similar to the main knife (1), mounted on the substructure (3) and located in the plane of the main knife (1), the teeth of the additional knife (14 ) are aligned symmetrically to the teeth (5) of the main knife (1) and shifted from each other. Apparatus according to claim 4, characterized in that the additional knife (14) with the main knife (1) is designed as a whole. Device according to claim 4, characterized in that the teeth (5) are designed individually and are mounted on the plate (4) with the possibility of changing their position in order to align the cutting edges (6) of the teeth (5) in one plane. Apparatus according to claim 4, characterized in that a section (17), the length of which is approximately 1/3 to approximately 1/4 of the total length (7) of the knife (1), on the shorter side (18) of the knife (1) adjoins that the tips (16) of the cutting edges (6) of the teeth (5) of this section (17) are on a line with a smaller angle (β) to the relative direction of movement of the knife (1) and the paper stack (2) than the angle (γ) of the remaining section (19) of the longer side (7) of the knife (1). Device according to claim 8, characterized in that the knife (1) is made from two connected plates (20 and 21), the connecting line (23) between the sections (17 and 19) of the longer side (7) of the knife (1 ) running. Apparatus according to claim 4, characterized in that it has two brackets (24 and 25) mounted on the substructure (3), one of which rests the knife (1) with the possibility of suspension and by means of a spring (26) resiliently opposite the second bracket (25 ) and is equipped with a stop (27) to limit the suspension angle of the knife (1). Apparatus according to claim 10, characterized in that the spring (26) has a possibility of regulating the spring pressure in the form of a screw (28) which is mounted on the holder (25) against which the knife (1) springs. Apparatus according to claim 10, characterized in that two parallel plates (29) are mounted on the base (3) on both sides at the level of the knife (1), which guarantee the direction of movement of the knife (1) when springing.

Images