DE102013004560A1 - Paper cutting knife for use in paper cutting machine for machine-cutting e.g. paper stack, has blade made of hard material and screwed with base body via screw connector and connected with base body by adhesive - Google Patents

Abstract

The knife (1) has a base body (2) made of metal for fastening at a paper cutting machine. A blade (3) is made of a hard material and screwed with the base body via a screw connector and connected with the base body by an adhesive. A sticking groove increases adhesive bond in the base body and/or the blade. The screw connector comprises an attachment screw (4) with a screw head, and a region between the screw head and the blade is filled with the adhesive. The base body is formed with a recess for receiving the blade. The base body is made of steel.

Description

The present invention relates to a paper cutting knife, which has a base body made of metal for attachment to a paper cutting machine and at least one fixed to the base body blade made of hard material.

For cutting paper products, in particular paper webs, paper stacks, magazines, etc., it is known to use particularly wear-resistant blades made of hard material. In the context of the present description, hard material is understood to mean carbide, cermet and cutting ceramics. Under cutting ceramics are understood to mean ceramics, which are also used in a metal cutting machining, in particular cubic boron nitride and polycrystalline diamond. Hard metal (also referred to as "cemented carbide") is understood herein to mean a material in which hard metal carbides are embedded in a metallic matrix (binder). The metal carbides may be formed in particular by carbides or mixed carbides of the metals of groups IV to VI of the Periodic Table of the Elements, in particular z. As by carbides or mixed carbides of the metals W, Ti, Zr, Hf, V, Nb, Ta, Mo and Cr. The metallic matrix can, for. B. in particular be formed by Co, Ni and / or Fe. There may also be additives of other hard materials. Cermet is understood as meaning a material in which ceramic particles, which can be formed in particular by carbon oxides, oxides, borides or carbides, are embedded in a metallic matrix. The metallic matrix may in particular comprise cobalt (Co), tungsten (W), molybdenum (Mo), niobium (Nb), titanium (Ti), zirconium (Zr), chromium (Cr) and / or nickel (Ni). In the case of paper cutting knives, carbide is frequently used in particular.

It is basically known, for. B. paper cutting knife made of solid carbide. In this case, however, a large amount of high quality raw material is required for at least large paper cutting knives and costly grinding is required. For these reasons, a design made of solid carbide usually comes only in small Papierschneidmessern in question.

For larger paper cutting knives, it is known to provide a base body made of metal, in particular made of steel, with a fixed to the body blade (or more blades) made of hard material.

EP 1 992 458 A1 describes a knife for use in a machine for cutting or punching sheet stacks. A carbide insert forming the cutting edge is received in a recess in a main body of the knife.

When a hard-material blade is bonded to the body by brazing, stress cracks in the hard material may occur due to widely differing coefficients of expansion of the materials. To avoid this, the properties of the hard material must be designed strongly with respect to the properties of the body. Consequently, an optimization of the hard material with respect to the material to be cut is only very limited possible.

It is an object of the present invention to provide an improved paper cutting knife in which an adaptation of the material of the blade to the material to be cut is highly possible and at the same time a durable, reliable connection between a blade made of hard material and a base body is provided

The object is achieved by a paper cutting blade according to claim 1. Advantageous developments are specified in the dependent claims.

The paper cutting knife can be designed in particular for the automatic cutting of single paper or paper stacks and has a basic body made of metal for attachment to a paper cutting machine and at least one blade attached to the main body made of hard material. The at least one blade is bolted to the base body via at least one screw connection and also connected to the base body in a material-locking manner by means of an adhesive.

A reliable connection is provided via the screw connection, which reliably prevents the hard-material blade from detaching itself from the base body, even at high cutting forces and beating cuts. The additional material-locking connection by means of an adhesive damping between the blade made of hard material and the base body is provided. In particular, in an automatic operation of a paper cutting machine thus vibrations are reliably damped in the system. Furthermore, unevennesses of the surfaces of the main body and / or the blade are reliably compensated with the adhesive, so that manufacturing tolerances are compensated. On the hard material acting stresses are reduced in this way. Due to the adhesive, the screw connection is reliably secured against loosening. Compared with a pure adhesive connection thus a much more reliable backup is provided. Compared with a pure screw connection, a significantly lower stress on the hard material is achieved. Consequently, the properties of the hard material can be optimized with respect to the material to be cut and the coefficient of thermal expansion of the hard material no longer has to be so closely matched to the material of the base body. Since no high heat input is required to form the reliable connection, as would be required when soldering the blade to the body, occur in the compound even in the presence of different expansion coefficients no high voltages and it can, for. As carbide grades with high edge sharpness, such as in particular those with Mo, Cr, Re, Ni and / or V are used as carbide and / or alloying additive. It is Z. As well as a reduction of the proportion of a binder, such as Co, Fe, Ni and their alloys, possible or it can also coated hard materials are used to a greater extent, as caused by soldering heat input does not occur.

According to a development, at least one adhesive groove for reinforcing the adhesive bond in the base body and / or the blade is formed. It can be z. For example, one or more adhesive grooves may be formed in the body, one or more adhesive grooves may be formed in the blade, or one or more adhesive grooves may be provided both in the body and in the blade. An adhesive groove is understood in the present context to mean a recess which receives adhesive and thus locally reinforces the thickness of the adhesive layer. By providing adhesive grooves, the resulting holding force and / or damping effect of the adhesive can be adjusted specifically. Thus, a particularly reliable connection can be provided.

According to a development, at least one adhesive groove for reinforcing the adhesive bond is formed on a side of the blade opposite the cutting edge of the blade and / or of the base body. In this case, occurring in the cutting process striking forces between the blade and the body can be particularly reliably damped. The adhesive groove (or more) can be formed as a depression in the blade or as a recess in the body. It is Z. B. but also possible to form the glue groove by depressions in both the base body and the blade.

According to a further development, at least one adhesive groove for reinforcing the adhesive bond is formed on a contact surface of the blade and / or of the base body which is adjacent to the cutting edge. In this case, the adhesive bond can be reliably reinforced in the area of a large, flat support surface. The adhesive groove (or more) may in turn be formed as a depression in the blade, as a depression in the base body or by depressions in both the blade and the base body. Preferably, a plurality of adhesive grooves, in particular two, three or four adhesive grooves, may be provided.

According to a development, the screw connection has at least one fastening screw with a screw head and at least one region between the screw head and the at least one blade is filled with adhesive. In this case, a damping between the fastening screw and the blade are provided by the adhesive at the same time and reliably secured the screw against loosening. In addition, a smooth surface of the paper cutting knife can be provided.

According to a development, at least one area between the blade and the main body is filled with adhesive. In this case, beating cutting forces do not act directly on a contact point between the blade and the base body, but it is provided by the adhesive damping. Furthermore, a large-area, uniform connection between the base body and blade is made possible in this way. It can be z. B. be provided only in one area or more areas between the blade and the body adhesive. It is Z. B. but also possible to provide in the entire area between the base body and blade a layer of adhesive, so that a particularly effective damping is achieved. Particularly preferred is a layer of adhesive is provided, which has a uniform thickness. This can be z. B. be achieved by embedded in the adhesive layer spacers.

If the base body is formed with a recess for receiving the blade, stable storage of the blade and a large-area adhesive connection are made possible. Preferably, the recess may limit the blade at least on two sides, so that a particularly stable storage is provided.

According to a development, a plurality of blades is arranged on the base body. In this way, even very large paper cutting knives can be provided in a cost effective and stable manner by forming one blade area by a plurality of separate, juxtaposed blades.

If the material-locking connection is formed by means of a cold-curing adhesive, an undesirable high temperature entry in the formation of the material-locking connection is reliably avoided. Preferably, the base body may be formed of steel.

According to a development, the screw connection has at least one fastening screw with a screw head, which tapers in the direction of a threaded section. In this case, a damping adhesive layer between the screw head and the blade can be permanently introduced particularly reliably. Preferably, a plurality of such fastening screws may be provided. In the case of a plurality of blades, the individual blades may preferably be screwed to the base body in each case with such fastening screws.

Further advantages and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying figures.

From the figures show:

1 a schematic plan view of a paper cutter according to an embodiment;

2 a schematic partial section along a line DD in 1 ; and

3 a schematic partial section along a line AA in 1 ,

An embodiment will be described below with reference to FIGS 1 to 3 described.

The paper cutter 1 According to the embodiment is designed for machine cutting of single paper or paper stacks and has a main body 2 and a blade attached to it 3 on. Although an embodiment will be described below in which a single blade 3 on the body 2 is arranged, the blade portion may also be formed divided so that a plurality of blades 3 next to each other on the body 2 is attached. Such a subdivision into a plurality of blades 3 is in 1 schematically represented by dashed lines L. The following is a subdivision into a plurality of blades 3 not described in more detail, it is understood, however, that the possibility of a plurality of on the main body 2 attached blades 3 should always be included in the following description.

The main body 2 is formed of metal and can be made in particular of a tool steel. The main body 2 is designed for attachment to a component of a paper cutting machine. In the illustrated embodiment, the base body 2 z. B. a plurality of holes 2a on, over which the main body 2 can be firmly connected to the paper cutting machine. The main body 2 has a strip-like elongated shape and a longitudinal side of the body 2 is with a flat, elongated recess 21 for receiving the blade 3 or blades 3 provided, as in particular in the schematic sectional view of 3 you can see.

The recess 21 is so in the body 2 formed, that the recess 21 along the longitudinal side of the body 2 as to the longitudinal side and to a first main surface 22 open recess extends in which the blade 3 (or more) can be accommodated such that the side walls of the recess 21 the blade 3 limit on two sides. On the first main surface 22 opposite second major surface 23 is the main body 2 formed inclined towards the longitudinal side, so that the thickness of the body 2 rejuvenated in this direction. In the main body 2 is in the area of a floor area 24 the recess 21 a plurality of threaded holes 25 for mounting fastening screws 4 intended. In the embodiment, the threaded holes 25 while in a remote from the longitudinal side region of the recess 21 near a side wall 26 the recess 21 formed and extend substantially perpendicular to the first main surface 22 ,

In the illustrated embodiment is in the bottom surface 24 the recess 21 a plurality of adhesive grooves 5 whose function will be described in more detail. The glue grooves 5 are as depressions in the bottom surface 24 educated. Although in 3 for example, two glue grooves 5 in the floor area 24 are shown, z. As well as more or less adhesive grooves 5 be educated. Furthermore, z. B. also in the side wall 26 the recess 21 one or more glue grooves 5 be educated.

The blade 3 is formed of a hard material and may be formed in particular of hard metal. The blade 3 has a plate-like, elongated shape, one longitudinal side wedge-like to a sharp cutting edge 31 rejuvenated. The blade 3 is so in the recess 21 arranged that from the cutting edge 31 opposite other longitudinal side 32 the side wall 26 the recess 21 is facing. A first main surface 33 the blade 3 extends substantially flush with and parallel to the first major surface 22 of the basic body 2 , The opposite second main surface 34 the blade 3 is the floor area 24 the recess 21 facing and extending substantially parallel to this. The second main surface 34 the blade 3 and the floor area 24 thus form bearing surfaces of the blade 3 or of the basic body 2 ,

In the illustrated embodiment is in the of the cutting edge 31 opposite other longitudinal side 32 the blade 3 an adhesive groove 6 provided as a recess in the material of the blade 3 is trained. Although in 3 for example, such an adhesive groove 6 can also be a plurality of such adhesive grooves 6 be provided. Furthermore, one or more adhesive grooves may also be used 6 in the second main surface 34 the blade 3 be educated.

In an area near the long side 32 is in the blade 3 a plurality of holes 35 for receiving the fastening screws 4 intended. In 3 is an example of one of these holes 35 shown. The hole 35 points to the second major surface 34 side facing a first bore portion having a diameter which is slightly larger than the outer diameter of the threaded portion of the fastening screws 4 is. On the first main surface 33 the blade 3 facing side, a second bore portion is formed with a larger diameter, which is dimensioned such that in this the screw head of the fastening screw 4 is receivable. The first bore section merges stepwise into the second bore section, so that a shoulder is formed at which the screw head of the fastening screw 4 can support the blade 3 against the main body 2 to screw.

The blade 3 (or the plurality of blades 3 ) is by means of the fastening screws 4 via a screw connection with the main body 2 screwed.

According to the embodiment, an adhesive is in the space between the second main surface 34 the blade 3 and the floor area 24 brought in. Likewise, glue is in the space between the long side 32 the blade 3 and the side wall 26 brought in. The space between the screw head of the fixing screw 4 and the wall of the hole 35 is also filled with glue. In the embodiment, the adhesive is in particular formed by a cold-curing adhesive. Thus, the blade is 3 in addition to the previously described screw material fit by means of the adhesive to the body 2 connected. It is thus also an adhesive bond between the body 2 and the blade 3 educated. In the embodiment, both the areas between the blade 3 and the body 2 as well as the area between the fixing screws 4 and the blade 3 filled with glue. In this way, it is reliably ensured that the adhesive in use of the paper cutter 1 dampening effect. Through the glue grooves 5 . 6 the adhesive bond is strengthened locally, so that a special stability of the material connection is achieved. The adhesive also resembles unevenness of the surfaces of the body 2 and the blade 3 out.

Preferably, at least one outwardly exposed surface of the adhesive is ground. The grinding can preferably take place after complete curing of the adhesive. Preferably, all exposed surfaces of the adhesive may be ground so that a smooth surface of the paper cutting knife is provided.

When the fixing screw 4 is provided with a screw head whose outer diameter tapers in the direction of the threaded portion, the adhesive can be particularly effective in the area between the screw head and the threaded bore 35 provide damping. Preferably, the fastening screws 4 An extremely flat screw head, so that a small height of the paper cutter is possible. The screw head can z. B. in particular be provided with a Torx ^® profile for applying the tightening torque.

To ensure a uniform thickness of the adhesive layer between the blade 3 and the body 2 to achieve, for. B. remaining in the adhesive layer spacers in the space between the blade 3 and the body 2 be introduced.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1992458 A1 [0005]

Claims (13)

Paper cutting knife ( 1 ), in particular for the automatic cutting of single paper or paper stacks, comprising: a base body ( 2 ) of metal for attachment to a paper cutting machine and at least one of the base body ( 2 ) fixed blade ( 3 ) made of hard material, characterized in that the at least one blade ( 3 ) via at least one screw connection with the main body ( 2 ) screwed and also material fit by means of an adhesive to the main body ( 2 ) connected is. Paper cutting knife according to claim 1, characterized in that at least one adhesive groove ( 5 . 6 ) for reinforcing the adhesive bond in the base body ( 2 ) and / or the blade ( 3 ) is trained. Paper cutting knife according to one of the preceding claims, characterized in that at least one adhesive groove ( 5 . 6 ) for reinforcing the adhesive bond on one of the cutting edge ( 31 ) of the blade ( 3 ) opposite side of the blade ( 3 ) and / or the basic body ( 2 ) is trained. Paper cutting knife according to one of the preceding claims, characterized in that at least one adhesive groove ( 5 . 6 ) for reinforcing the adhesive bond on one of the cutting edge ( 31 ) adjacent bearing surface of the blade ( 3 ) and / or the basic body ( 2 ) is trained. Paper cutting knife according to one of the preceding claims, characterized in that the screw connection at least one fastening screw ( 4 ) with a screw head and at least one area between the screw head and the at least one blade ( 3 ) is filled with adhesive. Paper cutting knife according to one of the preceding claims, characterized in that at least one region between the blade ( 3 ) and the basic body ( 2 ) is filled with adhesive. Paper cutting knife according to one of the preceding claims, characterized in that an exposed surface of the adhesive is ground. Paper cutting knife according to one of the preceding claims, characterized in that the basic body ( 2 ) with a recess ( 21 ) for receiving the blade ( 3 ) is trained. Paper cutting knife according to claim 8, characterized in that the recess ( 21 ) the blade ( 3 ) limited at least on two sides. Paper cutting knife according to one of the preceding claims, characterized in that a plurality of blades ( 3 ) on the base body ( 2 ) is arranged. Paper cutting blade according to one of the preceding claims, characterized in that the material-locking connection is formed by means of a cold-curing adhesive. Paper cutting knife according to one of the preceding claims, characterized in that the basic body ( 2 ) is formed of steel. Paper cutting knife according to one of the preceding claims, characterized in that the screw connection at least one fastening screw ( 4 ) with a screw head, which tapers in the direction of a threaded portion has.

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