AT397481B - CIRCULAR KNIFE SCISSORS - Google Patents

Description

AT397481B

The invention relates to a circular knife scissors for separating thin single-layer or multi-layer flat materials according to the concept of claim 1.

The given circular knife scissors should make it possible to use thin single-layer, in particular multi-layer, sheets of materials with low tear strength, such as. As newsprint, or from materials with high elongation at low mechanical stresses, such as. B. aluminum and plastic films, avoiding the formation of waves and wrinkles in the entry area with high accuracy and quality cut strips. Furthermore, a safe pull-in into the scissors is to be ensured and a dust accumulation or dust development when slitting cut material, which is formed with several layers of thin fibrous or fibrous material, is reduced or avoided.

It is known to cut strips, sheets or the like into strips using a circular knife scissors consisting of a knife and a counter knife, which interact in a cutting manner. The knife and the counter knife of the scissors can be arranged on two moving or driven shafts. To guide the sheet material, it is known to move elements in the radial direction, for. B. pressure rings to provide between two cutter disks or counter-cutter disks, which presses the clippings onto the end face of the counter-cutter disks or cutter disks interacting with the cutter. The cutter and counter-cutter disks have a cutting edge angle of approximately 90 °.

When separating thin, possibly elastic or compressible materials, whereby the material to be cut can be formed from one, in particular also from several, layer (s), tensile stresses arise at right angles to the cutting direction due to the cutting edge angle of 90 °, which means that materials with low tensile strength can lead to tearing or at least to an unclean cut with increased dust accumulation. In the case of materials with high elongation, these tensions can result in unclean cuts and the flat material on the entry side of the scissors can be drawn together and shaped in a wave shape. The so-called cherry core effect can also hinder the pulling of such thicker clippings into the cutting area of the scissors.

In order to avoid the formation of a gap between the cutting edges, it has already been proposed (DE-OS-37 01 716) to press the disc knives of a knife shaft against the side flanks of the cylindrically shaped grooving knives of the counter knife shaft by means of disc springs in order to prevent low tensile stresses by an exact interaction of sharp cutting edges to reach the foils during the cut. Furthermore, a roller-shaped design of the knife and counter knife shafts with displaceable elastic measuring rings (US Pat. No. 4,275,631) should enable advantageous precise positioning of the measuring rings between the counter knife members.

Attempts have already been made to form knife and counter knife disks with acute-angled cutting edges. However, an exact, flat guidance of a flat material is largely not possible. Furthermore, when cutting due to the interaction of two acute-angled wedge-shaped cutting edges, the strips are convexly bent open transversely to the cutting direction, which in the area of the entry can lead to a contraction or a wavy bending of the material to be cut, on the other hand, if the material is formed from several layers Cuttings the individual layers shifted against each other. This can result in uneven, wavy, saw-like stripes if wrinkles form. In the event of extreme wrinkling and the resulting overlapping of the cut, damage to the circular knife scissors is also possible.

In order to change the cutting width, it has been proposed according to US Pat. No. 4,757,732 to arrange the knife and counter-knife disks in frames which can be displaced relative to one another perpendicular to the cutting direction. In order to avoid sagging of the material to be cut, support rollers are arranged between the knife frames, which can also be moved. From DE-OS 34 01 958 a device for separating sheet-like structures has also become known, in which the sheet-like structure is guided and held between two mutually adjustable conveyor belts and the knife and counter knife is arranged between the interacting conveyor belts. In order to separate rolled-up band-shaped material when wrapping it into strips, with a reliable process taking place in a shorter time, it is proposed according to EP-Al-36 311 to use a cutting head which can be rotated about an external axis. The cutting head can be swiveled to remove the spool and insert a full roll, making this manipulation safer, in a shorter time and with less work. However, all known devices for slitting flat materials have the disadvantage of inaccurate or disadvantageous cutting.

The invention has for its object to provide a circular knife scissors of the type mentioned, in which a flat cutting material consisting of one or more layers, which is elastic or compressible, has low tensile strength or high elongation at low mechanical stresses, drawn into the scissors and divided into strips of constant width with good cut edge quality, with essentially no cut dust.

This object is achieved in a generic device by the characterizing features of claim 1. Advantageous refinements and developments of the invention are characterized in the subclaims.

Further details of the invention will be explained in more detail with reference to the description of the drawings.

AT 397 481B

1 shows a schematic longitudinal section through a circular knife scissors for different strip widths

2 shows a schematic longitudinal section through a circular knife scissors with elements for securing the strip discharge 5 Hg. 3 shows a schematic cross section of the circular knife scissors according to Hg. 2

Fig. 4 is a knife disc with wavy cutting edge formation

S shows a cross section (CD) of the knife disk according to FIG. 4.

In the circular knife shears shown in FIG. 1, circular knife disks (4) with acute-angled cutting edges, which have a cutting edge angle (a), are attached to a drivable shaft (2). The 10 cutting edge angle (a) is the angle which is included by the generatrix of the side surface perpendicular to the shaft axis and the conical end face of the knife disc. Two knife disks (4), which form a pair of knife disks, are arranged in such a way that the side surfaces each containing the cutting edges are furthest apart from one another, their distance corresponding to a strip width. In order to enlarge this one strip width, if advantageously the width of the individual knife disks (4) is chosen to be the same for economical storage, spacer rings (8) or again several spacer rings with certain widths can be arranged side by side according to a modular system for economic storage. Between the pairs of cutter disks (4) with spacing rings (8), if necessary, between them, a cutting spacer ring (6), (6b) is used to set a further strip width, or several cutting spacing rings (6), 20 (6a) are also used for the above reasons. Concentrically on the cutting distance rings (6), (6a), (6b) preferably substantially equally wide driving disks (7), (7a) are arranged between the individual pairs of knife disks or a knife disk and a stop for limiting the width of the shares.

These drive plates (7), (7a) are made of a resilient elastic material, e.g. B. rubber or the like, which largely prevents sliding on their surface, in particular of the sheet material (1), 25, and have an outer diameter which corresponds approximately to that of the cutter disks (4) or is larger.

On the countershaft (3), which can also be driven, largely cylindrical counter-knife disks (5), (5a) are arranged in such a way that their right-angled cutting edges and the acute-angled cutting edges of the knife disks (4) of the shaft (2) touch or overlap one another and produce a cut 30 Cooperation and the end faces of the counter-knife disks (5), (5a) on the driving disks (7), (7a) press against the surface. A setting or alignment of the counter-knife disks (5), (5a), which may have different thicknesses, on the counter-knife shaft is accomplished by counter-knife spacer rings (9), (9a), their individual thickness and number in each case again being able to be carried out side by side according to a type of modular system. 35 When cutting into strip-shaped parts, the material to be cut (1) is pressed in a straight line by the elastic, non-sliding drive plates (7), (7a) onto the counter-knife discs (5), (5a) and thus prevented from shifting sideways, with the acute-angled cutting edges of the knife disks (4) on the rectangular edges of the respective counter knife disks (5), (5a) bring about a sharp cut with high quality. If a table, possibly consisting of many layers, is fed to the circular knife shears, the driving disks on the one hand bring about a secure, uniform pulling of the material into the shears, on the other hand it is clamped down in a straight line or in the cutting area on the end faces of the counter knife disks (5), (5a) pressed, whereby a wave formation of the clippings in the entry area and occurrence of high tensile stresses in the layers are largely avoided.

Fig. 2 shows elements (10), (11) for securing the strip discharge after the cut. The 45 ring-shaped elements (10), (11) which are preferably rotatable about their axis and have a larger diameter than the knife disks, are in the cutting area in the concave space between the cutting edges of a pair of knife disks (4), (4 ') and / or in the opposite space between the counter-cutter discs (5), (5 ') are arranged in such a way that they do not cause any disruptive compressive forces on the material to be cut (1). This embodiment has the advantage that no additional tensile stresses 50 are formed in the clippings. However, fixed elements for securing the strip discharge can also be provided, which protrude like tongues from the discharge side into the space between the knife disks (4), (4 ') and / or into the space between the counter knife disks (5), (5') . Furthermore, it can be advantageous to design the counter-knife discs in two parts with the interposition of a spacer ring with a smaller diameter or in one part with a face-side groove and to arrange a ring (13), (14) with 55 material properties, such as essentially that of the drive plate, in the cavity created. This has the advantage of further securing the retraction of a tabular clippings (1).

Fig. 3 shows schematically in cross section devices (12) and (12 '), by means of which annular elements can advantageously be held and displaced in the discharge direction. As a result, the strips can be discharged essentially in a straight line, even if there are any clamps between the 60 cutter disks.

4 shows a knife disc with a wave-shaped cutting edge formation. Thereby in the -3-

Claims (11)

AT 397 481B tapered end face of the cutter disc (4) alternating cylindrical jacket partial surfaces (41) are introduced at an angle.This shape of the cutting edge enables an additional reduction in the cutting pressure. A further embodiment of the invention provides for, if necessary, smoothing, in particular, several Lay existing, clippings to arrange at least one drivable pair of rollers in front of the cutting elements. The rollers can advantageously be made of an elastic material such as. B. be formed rubber or foam and extend substantially over the entire width of the entry area of the circular knife scissors, an embodiment with narrow rollers and counter-rollers distributed over the length of the shafts is economically advantageous. 10 The design of the circular knife scissors also increases the amount of cut dust decreased. According to the invention, a further reduction in the development of dust with an increase in the cutting edge retention of the knives and improved operational safety of the scissors is achieved by hardening and / or coating the surfaces of the measuring and counter knife disks. The surface can be hardened, for example, by nitriding and is particularly wear-resistant; coating the panes with 15, for example, M0S2 or, if appropriate, with hard materials such as TiN and the like, using a CVD or PVD process, in particular has an improving effect on the sliding properties of the surfaces and thus reduces the amount of cut dust. 20 PATENT CLAIMS 25 1. Circular knife scissors for cutting thin single or multi-layer flat materials that have low tear strength or high elongation at low mechanical stresses, such as. B. paper, textiles, plastic films, optionally aluminum foils, and the like, in strip-shaped parts, 30 consisting of two oppositely rotating axially parallel cutter shafts with cutter disks, the cross-section in the axial direction of the shaft acute, z. B. have cutting edges formed by a V-shaped recess in the end face and cylindrically shaped counter-cutter disks which interact to produce cutting, and pressure rings for guiding the material to be cut and spacer rings between the cutter disks and possibly rings for securing the strip discharge, characterized in that 35 on a cutter shaft ( 2) Knife discs (4) each with parallel side faces and with an acute-angled cutting edge, which is formed by the conical design of the end face and has a cutting edge angle (a) between the generatrices of a side face and the end face of at most 60 °, with the interposition of cutting distance rings ( 6) with a width that corresponds to the required strip width (s) of the material to be cut (1), such that the side surfaces containing the 40 cutting edges of two adjacent discs (4,4 ') are furthest apart from one another and if necessary for setting a further strip width of the material to be cut (1) spacer rings (8) for spacing the knife disks (4) from one another are provided and between the side surfaces of the knife disk pairs (4, 4 ') containing the cutting edge a driver disk (7) formed with elastic material , which is supported on the one hand on a cutting distance ring (6), is arranged 45, which drive disc (7) on the other hand during the separation with the interposition of clippings (1) on the end face of one counter knife disc (5) arranged on an opposite knife shaft (3) ), which, as is known per se, is largely cylindrical with right-angled cutting edges and can have pressure rings (13, 14) for taking the cut material (1) with it, pressing against the surface, coordinated with the distance between the cutting edges of the cutting disks (4,4 ' ) the counter knife disks (5) 50 by counter knife spacer rings (9,9a, 9b) po can be positioned, overlapping one another and strip discharge rings (10, 11) for securing the strip discharge are each arranged in the area of a pair of knife disks (4, 4 '). 2. Circular knife shears according to claim 1, characterized in that the surfaces of the knife disks (4) 55 and counter knife disks (5), in particular the surfaces forming the cutting edges, are hardened and / or coated. 3. Circular knife shears according to one of claims 1 or 2, characterized in that further spacer rings (8, 6a, 9a) with the same thickness are arranged on the knife shafts in order to enlarge the strip width. -4- 60 AT 397 481B 4. Circular knife scissors according to one of claims 1 to 3, characterized in that the driving disks (7) and optionally the pressure rings (13, 14) for taking the cut material out of a material (for example plastic, rubber and the like) are formed , which largely prevents slippage of the, in particular tabular, clippings at low surface pressures. 5. Circular knife shears according to one of claims 1 to 4, characterized in that in the free space, which is formed by the conical end faces of the opposite, optionally with the interposition of a spacer ring (8) adjacent knife disks (4,4 '), a strip discharge ring (10) is arranged, which element is held or guided by guide rollers (12) and, if necessary, displaceable in the discharge direction and preferably at a distance from the clippings (1) or bears against it without pressure force. 6. Circular knife shears according to one of claims 1 to 5, characterized in that a strip discharge ring (11) is arranged in the gap between two counter-knife discs, which ring is held or guided by guide rollers (12) and is optionally displaceable in the discharge direction and preferably in the cutting area for Cut material (1) has a distance. 7. Circular knife shears according to claim 5 or 6, characterized in that the strip discharge rings (10, 11) are formed by largely loosely guided rings. 8. Circular knife shears according to one of claims 1 to 4, characterized in that fixed tongues are arranged to secure the strip discharge from the discharge side into the free space between the knife disks and / or in the space between the counter knife disks. 9. Circular knife shears according to one of claims 1 to 8, characterized in that the cutting edge of the cutter disc (4) is wave-shaped and the conical end face of the cutter disc (4) alternately has cylindrical surface partial surfaces (41) at an angle to the side surface, the angle being greater than the cutting edge angle (a). 10. Use of a circular knife scissors according to one of claims 1 to 9, for separating single or multi-layer paper sheets strip-shaped parts. 11. Use of a circular knife scissors according to one of claims 1 to 9, for separating single or multi-layer sheets of foils, in particular non-ferrous metal foils, into strip-shaped parts. With 3 sheets of drawings -5-