EP0266447B1 - Rotating cutter, especially for a plastic granulator - Google Patents

Rotating cutter, especially for a plastic granulator Download PDF

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Publication number
EP0266447B1
EP0266447B1 EP86115293A EP86115293A EP0266447B1 EP 0266447 B1 EP0266447 B1 EP 0266447B1 EP 86115293 A EP86115293 A EP 86115293A EP 86115293 A EP86115293 A EP 86115293A EP 0266447 B1 EP0266447 B1 EP 0266447B1
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EP
European Patent Office
Prior art keywords
cutting
clamping
tool body
longitudinal groove
tool according
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP86115293A
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German (de)
French (fr)
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EP0266447A1 (en
Inventor
Hans Hench
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Individual
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Individual
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Priority to EP86115293A priority Critical patent/EP0266447B1/en
Priority to DE8686115293T priority patent/DE3671605D1/en
Priority to AT86115293T priority patent/ATE53178T1/en
Publication of EP0266447A1 publication Critical patent/EP0266447A1/en
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Publication of EP0266447B1 publication Critical patent/EP0266447B1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C18/00—Disintegrating by knives or other cutting or tearing members which chop material into fragments
    • B02C18/06—Disintegrating by knives or other cutting or tearing members which chop material into fragments with rotating knives
    • B02C18/16—Details
    • B02C18/18—Knives; Mountings thereof
    • B02C18/186—Axially elongated knives

Definitions

  • the invention relates to a concentric cutting tool, in particular for strand pelletizing of plastics, with the features of the preamble of patent claim 1.
  • a cutting tool in the form of a rasp with these features is known from FR-A 2 180 088.
  • the cutting elements which are designed in the manner of laterally limited parallel blades, are only held in a frictional manner in the longitudinal grooves between parallel clamping surfaces of the groove side wall and the clamping element.
  • high dynamic centrifugal stress there is therefore the risk that the cutting elements work radially forwards, which is inadmissible, for example, with a rotating cutting tool that is intended for strand pelletizing of plastics, because the cutting elements would run onto the fixed counter knife.
  • cutting elements in the form of V-shaped blow bars are inserted into the longitudinal grooves of the tool body and are fixed in position by means of wedge-shaped clamping or clamping elements. Because of the special design of these blow bars, they can only be pulled laterally out of the tool body after loosening the clamping or clamping elements, which is cumbersome and often requires large dismantling work of the associated machine for reasons of space.
  • two strip-like cutting elements are arranged in the lateral recesses of the two side walls of a longitudinal groove, which are clamped by an intermediate wedge, which is pulled towards the bottom of the longitudinal groove by a clamping screw penetrating it is.
  • the cutting elements are narrow strips which are delimited on the sides with parallel flanks and are not supported in the radial direction to the outside. It is therefore necessary to apply relatively large clamping forces from the wedge-shaped clamping element, which widens towards the circumference of the tool body, in order to ensure that the clamping elements are held securely by friction against the action of the centrifugal forces acting on them.
  • the narrow, strip-like, laterally parallel-flanked knives are in longitudinal grooves of rectangular cross-section Knife shaft body clamped.
  • wedge-shaped clamping elements are arranged in the longitudinal grooves behind the knives, a movable intermediate holder being held in the knife shaft body in a form-fitting manner between the knife and such a clamping element for transmitting the clamping force applied by the clamping element.
  • the clamping elements supported by compression springs against the bottom of the longitudinal groove are tapered in cross-section towards the circumference of the knife shaft body, so that they are pulled outwards under the influence of the centrifugal forces acting on them during operation and thus increase the clamping force for the knives.
  • the narrow knives are also held in this knife shaft in the radial direction without support only frictionally, the intermediate holder arranged in each longitudinal groove of the knife shaft body means an additional effort.
  • the object of the invention in contrast, is to provide a concentric cutting tool, in particular for strand pelletizing of plastics, which is distinguished by a particularly simple construction, allows easy and convenient replacement of the cutting elements from the circumferential side of the tool body and, moreover, above all a flawless, ensures secure holding of the cutting tools.
  • the wedge-shaped clamping element is clamped directly between the support surface of the cutting element and the opposite longitudinal groove side wall, there is no need for any intermediate holders or elements, so that the cutting element holder is of a very simple construction.
  • the radial support of the cutting elements towards the outside ensures that the centrifugal forces acting on it during operation are reliably excluded, so that there is always a correct and correct clamping of the cutting elements in the longitudinal grooves.
  • the assembly and replacement of the cutting elements from the circumferential side of the tool body are effortless: it is sufficient to use a suitable device to press the wedge-shaped clamping element radially inwards against the action of the clamping means or after loosening them in the respective longitudinal groove, thus reducing the cutting element from its radial support comes loose and can be removed freely from the longitudinal groove.
  • the new cutting element only needs to be inserted in the correct position, whereupon the clamping element is made effective, which is pressed radially outward by its clamping means into the wedge-shaped space between the supporting surface of the cutting element and the opposite longitudinal groove side wall and thus the clamping of the radially supported cutting element on the Tool body guaranteed.
  • the centrifugal forces then occurring during operation cannot lead to a release of the tension of the cutting elements; at most, they reinforce the clamping forces exerted by the clamping elements.
  • the seat surface is arranged with its track forming a secant to form a circle representing the outline of the tool body, so that on the one hand there are favorable cutting conditions for the cutting elements and on the other hand the radially directed centrifugal forces acting on them are perpendicular to the one
  • Have seat surface acting component that increases the pressure of the clamping surface of the cutting elements on the seat surface.
  • Suitable selection of the position of the plane containing the seat surface with respect to the axis of rotation of the tool body can achieve practically arbitrary clamping and support forces.
  • the support surface and the opposite longitudinal groove side wall can form a self-locking acute angle with one another, as a result of which the securing of the holder is further increased.
  • the seat is advantageously formed in or next to a recess of the tool body that extends laterally from the longitudinal groove, the bottom of which has an abutment for the cutting element. This ensures with simple means that after the insertion all cutting elements run with their cutting edges on a common circle of flies.
  • the bottom of the recess or areas of the tool body circumference can be designed as a contact surface for the cutting element, but embodiments are also conceivable in which adjustable adjusting elements are arranged in the arc of the longitudinal groove, which allow the system to be adjusted radially, in particular to coordinate the respective cutting element.
  • the clamping means pressing the clamping elements radially outward can have spring means, which in turn can expediently have at least one corrugated spring or at least one spring element made of an elastomeric material.
  • This spring element can be an elongated spring body which is inserted lengthways into the longitudinal groove, but embodiments are also conceivable in which the spring element is a spring pin which is arranged upright on the longitudinal groove base.
  • the spring element can also be at least one spring piston which acts against a gas cushion and acts in the manner of a gas spring.
  • each cutting element that projects into the longitudinal groove and is delimited by the clamping and supporting surface has an essentially wedge-shaped cross-sectional shape that tapers towards the circumference of the tool body.
  • the clamping and supporting surface can in turn have an acute angle of such a size that on the surfaces of the tool body and the clamping element interacting with them, i.e. the seat and the support surface, a self-locking effect occurs.
  • the two-legged cutting element has an essentially L-shaped cross section, at least one of its legs having a wedge-shaped cross-sectional shape.
  • the clamping surface is expediently arranged on the inner side of the associated leg.
  • the cutting element designed as an indexable cutting element can have two legs of the same design, each of which carries a cutting edge. It is also advantageous if the contact surface is arranged on the circumference of the tool body or a part connected to it next to the corresponding longitudinal groove.
  • the tool body can be solid at least in the outer circumferential areas, so that the longitudinal grooves are machined directly into the material of the tool body.
  • the longitudinal grooves are each formed in elongate cutting element carriers which are connected to the tool body or are arranged to form parts thereof.
  • the tool body consists of a number of coaxial, annular, axially braced sections and equipped with cutting elements, the cutting elements of which are butt-jointed at the parting joints of the sections, so that the axial length of the cutting tool result in continuous cutting edges.
  • the arrangement is such that adjacent sections on the facing end faces are rotatably connected to one another by fitting elements and spring parts acting in the axial direction are inserted between adjacent sections .
  • the tensioning means can also have at least one tensioning screw coupled to the tensioning element and / or the tool body or a part connected to it, which presses the tensioning element radially awake outward into the wedge-shaped tapering space.
  • tensioning screws can be present in addition to the spring means already mentioned, but embodiments are also conceivable in which the tensioning means are only formed by such tensioning screws.
  • the support surface of the cutting element is arranged in substantially flush alignment with the adjacent longitudinal groove side wall or only slightly protrudes beyond it into the groove interior.
  • FIG. 1 shows a rotary cutting tool according to the invention, in cross section, in detail and in a schematic representation, illustrating four different embodiments of the spring means assigned to the clamping elements
  • FIG. 2 shows a rotary cutting tool according to the invention, in cross section, in detail and in a schematic Representation, illustrating a modified embodiment of the cutting elements
  • Figure 3 shows the arrangement of Figure 2, illustrating another embodiment of the cutting elements in a corresponding representation
  • Figure 4 shows a multi-part tool body of a rotary cutting tool according to the invention, cut along the line IV-IV of the 5, in a side view
  • FIG. 5 the tool body according to FIG. 4, in a side view
  • FIG. 1 shows a rotary cutting tool according to the invention, in cross section, in detail and in a schematic representation, illustrating four different embodiments of the spring means assigned to the clamping elements
  • FIG. 2 shows a rotary cutting tool according to the invention, in cross section, in detail and in a schematic Representation, illustrating a modified embodiment of the cutting
  • FIG. 6 a cutting element carrier for use in the tool body according to FIG. 5, in a perspective view and in another dimension rod
  • FIG. 7 shows a rotary cutting tool composed of several tool bodies according to FIG. 4.5, according to the invention, in a top view, partially cut open and in a schematic representation
  • FIG. 8 shows two sections of a rotating cutting tool according to the invention, in a perspective schematic representation
  • FIGS 9, 10 shows a rotating cutting tool according to the invention, in cross section, in detail and in a schematic illustration, illustrating a modified embodiment of the cutting elements, and a clamping element of the arrangement according to FIG. 9, in a side view.
  • the rotary cutting tool shown in FIGS. 1-3 in detail has a solid, essentially sleeve-shaped or circular tool body 1, as is shown in principle in FIG.
  • This tool body 1 is intended - in particular together with other axially connecting, identical tool bodies 1 - to be arranged in a rotationally fixed manner on a shaft which at the end carries shaft journals with which the tool can be rotatably supported in corresponding bearings.
  • the cutting tool is used in particular for strand pelletizing of plastics and is excellently suitable for processing plastics which are difficult to granulate, for example those with admixtures of mineral fibers and the like.
  • the essentially cylindrical tool body 1 is formed on its circumference with a number of evenly distributed longitudinal grooves 2, which extend over the entire axial length of the tool body 1.
  • the longitudinal grooves 2 enclose a small angle of approximately 2 ° with the axis of rotation of the tool body 1, as is shown somewhat enlarged in FIG. 7 at 3.
  • a recess 4 extends laterally from each of the longitudinal grooves 2, which opens towards the circumference of the tool body 1 and whose side surface forms a seat surface 5 for a cutting element 6, 6a or 6b, which together with a clamping element 7 which is wedge-shaped in cross section, in the longitudinal groove 2 is housed.
  • the strip-like cutting elements 6, 6a, 6b preferably consist of hard metal, stellite or ceramic; they can be constructed in one or more parts, in which case cutting bars made of hard metal or the like are applied, for example soldered, to a corresponding carrier.
  • the cutting elements 6, 6a, 6b are basically arranged in the tool body 1 in such a way that their effective cutting edges 8 run on a common flight circle.
  • each of the cutting elements 6 is essentially L-shaped in cross section. It is therefore two-legged; his two legs are labeled 9 and 10.
  • the two legs 9, 10 are each essentially wedge-shaped in cross-section, the leg 10 lying in the longitudinal groove 2 having a wedge shape tapering towards the peripheral surface of the tool body 1. It is bounded on one side by a clamping surface 11 resting on the seat surface 5 and on the opposite side by a support surface 12 on which the wedge-shaped clamping element 7 acts, which in turn is supported against the side surface 13 of the longitudinal groove 2 opposite the support surface 12 .
  • the cutting element 6 With its leg 10, the cutting element 6 also lies on the base surface 14 of the associated recess 4, which thus forms a stop surface for the cutting element 6.
  • each cutting element 6 and the opposite longitudinal groove side wall 13 is tapered in a wedge shape towards the circumference of the tool body 1 educated.
  • the corresponding wedge-shaped clamping element 7, which tapers in the same direction, is pressed into this space by spring means which are arranged between the underside of the clamping element 7 and the bottom 15 of the longitudinal groove 2.
  • FIG. 1 Of these spring means, four different embodiments are illustrated in FIG. 1, which can be used alternatively:
  • the spring means are formed by at least one spring element made of an elastomeric material in the form of an elongated, cylindrical spring body 16, which is inserted lengthways into the longitudinal groove 2.
  • a corrugated or leaf spring 17 is inserted as the spring element in the longitudinal groove 2 adjoining on the right, while at least one spring piston 18 is arranged in the longitudinal groove 2 following on the right as spring means, which has a cylindrical piston neck 19 in a gas-filled cylinder space 20 formed in the tool body 1 protrudes, which is sealed against the piston neck via a corresponding sealing wall 21.
  • the spring piston 18 thus acting against a gas cushion is thus fundamentally similar to a gas spring.
  • the spring means are formed by spring pins 22 made of elastomeric material, which are inserted upright into corresponding bores 23 in the groove base 15.
  • each seat surface 5 is formed with its track a secant to a circle representing the outline of the tool body 1.
  • elements 6 in the radial direction attacking centrifugal forces therefore have a component that is perpendicular to the seat surface 5 and which strives to press the leg 10 with the clamping surface 11 against the seat surface 5.
  • the cutting elements 6 are supported radially on the tool body 1 by the inclined seating surfaces 5 and the cooperating, likewise inclined clamping surfaces 11.
  • each longitudinal groove encloses an acute angle, which results in a self-locking effect for the wedge-shaped clamping element 7, the size of which depends in individual cases on the material pairing that applies to the superimposed surfaces.
  • the clamping and support surface 11 and 12 of each cutting element 6 limit an acute angle of such a size that there is also a self-locking effect.
  • the clamping surface 11 of the cutting elements 6, which are essentially L-shaped in cross section, is arranged on the inner side of the associated leg 10.
  • the L-shaped cross-sectional shape of the cutting elements 6 brings with it the advantage of high stability of the cutting elements, while at the same time the area of the circumference of the tool body 1 which adjoins the cutting edge 8 in the cutting direction and which, according to experience, is particularly highly stressed, through the outer surface of the leg 9 of the respective hard metal, etc. existing cutting element is formed and is therefore particularly resistant.
  • flutes 24 are finally formed in the circumferential surface of the tool body 1 in the usual manner.
  • FIG. 2 differs from that according to FIG. 1 in that the cutting elements 6a are designed as so-called indexable cutting elements.
  • the two legs 9, 10 of the strip-like cutting elements 6a, which otherwise essentially correspond to the cutting elements 6, are both designed identically; each of them wears a cutting edge 8.
  • Each of the recesses 4 is designed with its seat 5 and its bottom surface 14 to match the shape of the two legs 9, 10, but the contact surface 14a is arranged next to the longitudinal groove 2 on the circumference of the tool body 1.
  • the same parts are therefore provided with the same reference numerals, so that a repeated discussion is unnecessary.
  • the strip-shaped cutting elements 6b are formed in one leg with an essentially wedge-shaped cross-sectional shape, the surfaces 11, 12 which laterally delimit the wedge shape being tapered radially outward.
  • the wedge-shaped clamping element 7 is arranged on the side of the leg 10 of the cutting element 6 or 6a facing away from the cutting edge 8, in the embodiment according to FIG. 3 the arrangement is such that the Clamping element 7 on the clamping surface 11 1 of the cutting element 6b containing the cutting edge 8, ie attacks on its front.
  • the tool body is designed in the manner of a so-called rotor 100.
  • the rotor 100 consists of a number of annular disks 30 which are clamped axially to one another by means of clamping bolts 31 in the manner shown in FIGS. 4 and 7.
  • the arrangement is such that 30 spacer sleeves 32 are arranged between the two external washers, through which the clamping screws 31 run, which are screwed into corresponding threaded bores 32 'of a centrally arranged hub disk 33, on which two further washers 30 rest on the end face.
  • the rotor 100 is covered on both end faces by cover caps 34 and, moreover, is placed on a shaft (not shown) in a rotationally fixed manner.
  • the ring disks 30 are provided on their circumference with open-edge grooves 200 which are aligned with one another over the axial length of the rotor 100.
  • Rail-shaped or strip-shaped cutting element carriers 35 as are illustrated in detail in FIG. 6, are inserted into the grooves 200 of adjacent annular disks 30.
  • Each of the cutting element supports 35 has two end flanges 36 which are substantially rectangular in cross section and which have holes 37 for fastening screws 38 which are screwed into corresponding threaded holes 39 on the bottom of the grooves 200 and are adapted to the shape of the grooves 200.
  • each cutting element carrier 35 is chamfered at 40 to ensure that the granulate produced can pass freely.
  • the cutting element carriers 35 are each designed with a continuous longitudinal groove 2, which has the cross-sectional shape shown in FIGS. 1-3 in the area between the end flanges 36. In it, the respective cutting element 6 (or 6a or 6b) is clamped by a wedge-shaped clamping element 7 in the manner shown in FIGS. 1 and 3.
  • the cutting element carriers 35 arranged on adjacent pairs of annular disks 30 are arranged with their cutting elements 6 butt-abutting, so that continuous cutting edges 8 result over the length of the rotor 100, which include the small angle 3 (FIG. 7) with the rotor axis of rotation 41.
  • Taper dowel pins 42 (FIG. 4) ensure an exact angular alignment of the ring disks 30 relative to one another.
  • the cutting tool consists of several coaxial sections, each of which is formed by a tool body 1, as has already been explained with reference to FIGS. 1-3.
  • These tool bodies 1 are non-rotatably mounted on a common shaft (not shown in FIG. 8) and axially clamped thereon, for example by a threaded ring.
  • a common shaft not shown in FIG. 8
  • axially parallel, cylindrical locating pins 44 and locating holes 45 associated therewith are arranged in the region of the end faces facing one another.
  • compression springs 47 are provided in corresponding bores 46, which strive to axially press the tool body 1 apart.
  • the radial support of the cutting elements 6, 6a, 6b on the tool body 1 or the cutting element carrier 35 can also take place in a form-fitting manner by means of an attachment 50 of the cutting element, as is schematically indicated in FIG. 1.
  • the cutting element 6, which is essentially L-shaped in cross section, is designed essentially as in FIG. 1.
  • the same parts are denoted here with the same reference numerals and are not explained in detail.
  • the recess 4 is so deep in the circumferential direction of the tool body 1 that the leg 10 of the cutting element 6 tapering in a wedge-shaped manner toward the circumferential surface of the tool body 1 is received essentially entirely in the recess 4.
  • Its support surface 12 projects only slightly beyond the adjacent longitudinal groove side wall into the interior of the longitudinal groove 2.
  • the tensioning element 7 with a laterally projecting shoulder resting on the support surface 12, it could also be aligned with the adjacent longitudinal groove side wall.
  • the wedge-shaped clamping element 7 has two bores 52 arranged at a distance, which open to the circumference of the tool body 1 and each of which receives a clamping screw 51.
  • the clamping screw 51 is screwed into a threaded bore 53 in the bottom of the bore 52 and is supported against the bottom 15 of the longitudinal groove 2.
  • Spring elements can be arranged between the tensioning screws 51, as explained in detail with reference to FIG. 1, but it is also possible to dispense with these spring elements in certain applications.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Milling Processes (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Abstract

1. A rotary cutting tool, more particularly for the continuous granulation of plastics, having a cylindrical tool body (1, 100) formed with a number of longitudinal grooves (2) uniformly distributed in the peripheral direction, each of which contains a releasably inserted, strip-like cutting element (6, 6a, 6b) and a clamping element (7) of wedge shaped cross-section which is disposed in the space, tapering in wedge shape in the direction of the periphery of the tool body (1), between a bearing surface (12) of the cutting element and the side wall (13) of the longitudinal groove opposite said bearing surface and has in cross-section a matching wedge shape tapering in the same direction and is pressed radially outwards by clamping means (16; 17; 18; 22) borne in the zone of the bottom (15) of the longitudinal groove into the space tapering in wedge shape, so that the cutting element is clamped via a clamping surface (11) remote from the clamping element against a seating surface (5) in the zone of the longitudinal groove, characterized in that that part of the cutting element which extends into the longitudinal groove in the tool body or in a member (35) connected thereto and is bounded by the clamping and bearing surfaces (11, 12) has a substantially wedge shaped cross-section tapering in the direction of the periphery of the tool body (1, 100) and having a maximum width smaller than the opening width of the longitudinal groove, and the tool body or the member (35) connected thereto has a bearing surface (14, 140) for the cutting element which determines the radial position of the cutting element.

Description

Die Erfindung betrifft ein rundlaufendes Schneidwerkzeug, insbesondere zum Stranggranulieren von Kunststoffen, mit den Merkmalen des Oberbegriffes des Patentanspruchs 1.The invention relates to a concentric cutting tool, in particular for strand pelletizing of plastics, with the features of the preamble of patent claim 1.

Ein in Gestalt einer Raspel ausgebildetes Schneidwerkzeug mit diesen Merkmalen ist aus der FR-A 2 180 088 bekannt.A cutting tool in the form of a rasp with these features is known from FR-A 2 180 088.

Bei diesem Werkzeug sind die nach Art von seitlich parallelflächig begrenzten Klingen ausgebildeten Schneidelemente in den Längsnuten zwischen parallelen Klemmfiäehen der Nutenseitenwand und des Spannelementes lediglich reibschlüssig gehalten. Bei hoher dynamischer Fliehkraftbeanspruchung besteht deshalb die Gefahr, daß die Schneidelemente sich radial etwas vorarbeiten, was bspw. bei einem rundlaufenden Schneidwerkzeug, das zum Stranggranulieren von Kunststoffen bestimmt ist, deshalb unzulässig ist, weil die Schneidelemente auf das feststehende Gegenmesser auflaufen würden. Außerdem ist es bei dem bekannten Schneidwerkzeug schwierig, die Schneidelemente mit ihren wirksamen Schneiden exakt auf einen gleichen Flugkreis einzustellen, weil keine formschlüssige radiale Abstützung der Schneidelemente vorhanden ist.In this tool, the cutting elements, which are designed in the manner of laterally limited parallel blades, are only held in a frictional manner in the longitudinal grooves between parallel clamping surfaces of the groove side wall and the clamping element. With high dynamic centrifugal stress there is therefore the risk that the cutting elements work radially forwards, which is inadmissible, for example, with a rotating cutting tool that is intended for strand pelletizing of plastics, because the cutting elements would run onto the fixed counter knife. In addition, it is difficult in the known cutting tool to set the cutting elements with their effective cutting edges exactly on the same flight circle, because there is no positive radial support for the cutting elements.

Bei einem aus der DE-C 930 839 bekannten Rotor für Schleudermühlen sind in die Längsnuten des Werkzeugkörpers Schneidelemente in Gestalt V-förmiger Schlagleisten eingesetzt, die mittels keilförmiger Spann- oder Klemmelemente lagefest fixiert sind. Wegen der besonderen Gestaltung dieser Schlagleisten können sie nach dem Lösen der Spann- oder Klemmelemente lediglich seitlich aus dem Werkzeugkörper herausgezogen werden, was umständlich ist und schon aus Platzgründen häufig größere Demontagearbeiten der zugehörigen Maschine erforderlich macht.In a rotor for centrifugal mills known from DE-C 930 839, cutting elements in the form of V-shaped blow bars are inserted into the longitudinal grooves of the tool body and are fixed in position by means of wedge-shaped clamping or clamping elements. Because of the special design of these blow bars, they can only be pulled laterally out of the tool body after loosening the clamping or clamping elements, which is cumbersome and often requires large dismantling work of the associated machine for reasons of space.

Bei einem aus der US-C 4 360 168 bekannten Schneidwerkzeug sind in seitlichen Ausnehmungen der beiden Seitenwände einer Längsnut jeweils zwei leistenartige Schneidelemente angeordnet, die durch einen dazwischenliegenden Keil verspannt sind, der durch eine ihn durchdringende Spannschraube in Richtung auf den Grund der Längsnut zu gezogen ist. Die Schneidelemente sind seitlich parallelflankig begrenzte schmale Leisten, die in Radialrichtung nach außen zu nicht abgestützt sind. Es müssen deshalb von dem sich zu dem Umfang des Werkzeugkörpers hin erweiternden keilförmigen Spannelement verhältnismäßig große Klemmkräfte aufgebracht werden, um eine sichere reibschlüssige Halterung der Spannelemente gegen die Wirkung der an ihnen angreifenden Fliehkräfte zu gewährleisten. Außerdem ist ein Austausch beschädigter oder abgenutzter Schneidelemente deshalb verhältnismäßig umständlich, weil dazu über die Länge des Schneidwerkzeuges eine beträchtliche Anzahl von Spannschrauben gelöst werden müssen, wobei noch hinzu kommt, daß die die Spannschraubenköpfe enthaltenden angesenkten Bohrungen in den Spannelementen durch eigene Abdeckelemente abgedeckt sind und erfahrungsgemäß nicht ausgeschlossen werden kann, daß die keilförmigen Spannelemente nach dem Lösen der Spannschrauben in den Längsnuten festsitzen und erst mühsam gelockert werden müssen.In a cutting tool known from US-C 4 360 168, two strip-like cutting elements are arranged in the lateral recesses of the two side walls of a longitudinal groove, which are clamped by an intermediate wedge, which is pulled towards the bottom of the longitudinal groove by a clamping screw penetrating it is. The cutting elements are narrow strips which are delimited on the sides with parallel flanks and are not supported in the radial direction to the outside. It is therefore necessary to apply relatively large clamping forces from the wedge-shaped clamping element, which widens towards the circumference of the tool body, in order to ensure that the clamping elements are held securely by friction against the action of the centrifugal forces acting on them. In addition, an exchange of damaged or worn cutting elements is relatively cumbersome because a considerable number of clamping screws have to be loosened over the length of the cutting tool, with the fact that the countersunk holes in the clamping elements containing the clamping screw heads are covered by their own cover elements and experience has shown It cannot be ruled out that the wedge-shaped clamping elements become stuck in the longitudinal grooves after loosening the clamping screws and only have to be loosened with difficulty.

Bei einem anderen rundlaufenden Schneidwerkzeug (DE-A2 2 208 687), das in Gestalt einer Messerwelle für Holzbearbeitungsmaschinen ausgebildet und deshalb nicht zum Stranggranulieren von Kunststoffen geeignet oder bestimmt ist, sind die schmalen leistenartig, seitlich ebenfalls parallelflanking begrenzten Messer in im Querschnitt rechteckigen Längsnuten des Messerwellenkörpers gespannt. Zu diesem Zwecke sind, in Umdrehungsrichtung der Messerwelle gesehen, hinter den Messern keilförmige Spannelemente in den Längsnuten angeordnet, wobei zwischen einem Messer und einem solchen Spannelement ein bewegbarer, formschlüssig in dem Messerwellenkörper gehaltener Zwischenhalter zur Übertragung der von dem Spannelement aufgebrachten Spannkraft vorgesehen ist. Die über Druckfedern gegen den Boden der Längsnut abgestützten Spannelemente sind im Querschnitt zu dem Umfang des Messerwellenkörpers hin sich verjüngend ausgebildet, so daß sie unter dem Einfluß der im Betrieb an ihnen angreifenden Fliehkräfte nach außen gezogen werden und damit die Klemmkraft für die Messer erhöhen. Die schmalen Messer sind aber auch bei dieser Messerwelle in Radialrichtung ohne Abstützung lediglich reibschlüssig gehalten, wobei der in jeder Längsnut des Messerwellenkörpers angeordnete Zwischenhalter einen zusätzlichen Aufwand bedeutet.In another rotary cutting tool (DE-A2 2 208 687), which is designed in the form of a knife shaft for woodworking machines and is therefore not suitable or intended for strand pelletizing of plastics, the narrow, strip-like, laterally parallel-flanked knives are in longitudinal grooves of rectangular cross-section Knife shaft body clamped. For this purpose, seen in the direction of rotation of the knife shaft, wedge-shaped clamping elements are arranged in the longitudinal grooves behind the knives, a movable intermediate holder being held in the knife shaft body in a form-fitting manner between the knife and such a clamping element for transmitting the clamping force applied by the clamping element. The clamping elements supported by compression springs against the bottom of the longitudinal groove are tapered in cross-section towards the circumference of the knife shaft body, so that they are pulled outwards under the influence of the centrifugal forces acting on them during operation and thus increase the clamping force for the knives. The narrow knives are also held in this knife shaft in the radial direction without support only frictionally, the intermediate holder arranged in each longitudinal groove of the knife shaft body means an additional effort.

Aufgabe der Erfindung ist es, demgegenüber ein rundlaufendes Schneidwerkzeug, insbesondere zum Stranggranulieren von Kunststoffen zu schaffen, das sich durch einen besonders einfachen Aufbau auszeichnet, ein leichtes und bequemes Auswechseln der Schneidelemente von der Umfangsseite des Werkzeugkörpers aus gestattet und darüber hinaus vor allem eine einwandfreie, sichere Halterung der Schneidwerkzeuge gewährleistet.The object of the invention, in contrast, is to provide a concentric cutting tool, in particular for strand pelletizing of plastics, which is distinguished by a particularly simple construction, allows easy and convenient replacement of the cutting elements from the circumferential side of the tool body and, moreover, above all a flawless, ensures secure holding of the cutting tools.

Zur Lösung dieser Aufgabe weist das eingangs genannte Schneidwerkzeug erfindungsgemäß die Merkmale des kennzeichnenden Teils des Patentanspruchs 1 auf.To achieve this object, the cutting tool mentioned at the outset according to the invention has the features of the characterizing part of patent claim 1.

Da das keilförmige Spannelement unmittelbar zwischen der Abstützfläche des Schneidelementes und der gegenüberliegenden Längsnutenseitenwand eingespannt ist, entfallen irgendwelche Zwischenhalter oder -elemente, so daß sich ein sehr einfacher Aufbau der Schneidelementhalterung ergibt. Durch die radiale Abstützung der Schneidelemente nach außen zu ist gewährleistet, daß die an ihm im Betrieb angreifenden Fliehkräfte sicher ausgenommen werden, so daß stets eine einwandfreie und lagerichtige Verspannung der Schneidelemente in den Längsnuten gegeben ist. Schließlich sind die Montage und der Austausch der Schneidelemente von der Umfangsseite des Werkzeugkörpers mühelos möglich: Es genügt dazu, mittels einer geeigneten Vorrichtung das keilförmige Spannelement gegen die Wirkung der Spannmittel oder nach deren Lösen in der jeweiligen Längsnut radial nach innen niederzudrücken, womit das Schneidelement von seiner radialen Abstützung loskommt und unbehindert aus der Längsnut entnommen werden kann. Das neue Schneidelement braucht lediglich lagerichtig eingelegt zu werden, worauf das Spannelement wirksam gemacht wird, das von seinen Spannmitteln in den keilförmigen Raum zwischen der Abstützfläche des Schneidelementes und der gegenüberliegenden Längsnutenseitenwand radial nach außen zu eingepreßt wird und somit die Verspannung des radial abgestützten Schneidelementes an dem Werkzeugkörper gewährleistet. Die betriebsmäßig dann auftretenden Fliehkräfte können zu keinem Lösen der Spannung der Schneidelemente führen; sie verstärken allenfalls noch die von den Spannelementen ausgeübten Spannkräfte.Since the wedge-shaped clamping element is clamped directly between the support surface of the cutting element and the opposite longitudinal groove side wall, there is no need for any intermediate holders or elements, so that the cutting element holder is of a very simple construction. The radial support of the cutting elements towards the outside ensures that the centrifugal forces acting on it during operation are reliably excluded, so that there is always a correct and correct clamping of the cutting elements in the longitudinal grooves. Finally, the assembly and replacement of the cutting elements from the circumferential side of the tool body are effortless: it is sufficient to use a suitable device to press the wedge-shaped clamping element radially inwards against the action of the clamping means or after loosening them in the respective longitudinal groove, thus reducing the cutting element from its radial support comes loose and can be removed freely from the longitudinal groove. The new cutting element only needs to be inserted in the correct position, whereupon the clamping element is made effective, which is pressed radially outward by its clamping means into the wedge-shaped space between the supporting surface of the cutting element and the opposite longitudinal groove side wall and thus the clamping of the radially supported cutting element on the Tool body guaranteed. The centrifugal forces then occurring during operation cannot lead to a release of the tension of the cutting elements; at most, they reinforce the clamping forces exerted by the clamping elements.

Zweckmäßig ist es, wenn die Sitzfläche mit ihrer Spur eine Sekante zu einem den Umriß des Werkzeugkörpers darstellenden Kreis bildend angeordnet ist, so daß sich zum einen günstige Schnittverhältnisse für die Schneidelemente ergeben, und zum anderen die an diesen angreifenden radial gerichteten Fliehkräfte eine rechtwinklig zu der Sitzfläche wirkende Komponente aufweisen, die die Anpressung der Spannfläche der Schneidelemente an der Sitzfläche vergrößert. Dabei können durch geeignete Wahl der Lage der die Sitzfläche enthaltenden Ebene bezüglich der Drehachse des Werkzeugkörpers praktisch beliebig große Klemm- und Abstützkräfte erreicht werden. Auch können die Abstützfläche und die gegenüberliegende Längsnutenseitenwand einen Selbsthemmung ergebenden spitzen Winkel miteinander einschließen, wodurch die Sicherung der Halterung weiter erhöht wird.It is useful if the seat surface is arranged with its track forming a secant to form a circle representing the outline of the tool body, so that on the one hand there are favorable cutting conditions for the cutting elements and on the other hand the radially directed centrifugal forces acting on them are perpendicular to the one Have seat surface acting component that increases the pressure of the clamping surface of the cutting elements on the seat surface. Suitable selection of the position of the plane containing the seat surface with respect to the axis of rotation of the tool body can achieve practically arbitrary clamping and support forces. The support surface and the opposite longitudinal groove side wall can form a self-locking acute angle with one another, as a result of which the securing of the holder is further increased.

Die Sitzfläche ist mit Vorteil in oder neben einer seitlich von der Längsnut abgehenden Ausnehmung des Werkzeugkörpers ausgebildet, deren Boden eine Anlage für das Schneidelement aufweist. Damit ist mit einfachen Mitteln gewährleistet, daß nach dem Einsetzen alle Schneidelemente mit ihren Schneiden auf einem gemeinsamen Fiugkreis laufen. Zur Erzielung dieser Anlage können bspw. der Boden der Ausnehmung oder Bereiche des Werkzeugkörperumfanges als Anlagefläche für das Schneidelement ausgebildet sein, doch sind auch Ausführungsformen denkbar, bei denen im Bogen der Längsnut verstellbare Justierelemente angeordnet sind, die es gestatten, die Anlage insbesondere radial auf das jeweilige Schneidelement abzustimmen.The seat is advantageously formed in or next to a recess of the tool body that extends laterally from the longitudinal groove, the bottom of which has an abutment for the cutting element. This ensures with simple means that after the insertion all cutting elements run with their cutting edges on a common circle of flies. To achieve this system, for example, the bottom of the recess or areas of the tool body circumference can be designed as a contact surface for the cutting element, but embodiments are also conceivable in which adjustable adjusting elements are arranged in the arc of the longitudinal groove, which allow the system to be adjusted radially, in particular to coordinate the respective cutting element.

Die die Spannelemente radial nach außen drückenden Spannmittel können Federmittel aufweisen, die ihrerseits zweckmäßigerweise wenigstens eine Wellfeder oder wenigstens ein aus einem elastomeren Material bestehendes Federelement aufweisen können. Dieses Federelement kann ein länglicher Federkörper sein, der der Länge nach in die Längsnut eingelegt ist, doch sind auch Ausführungsformen denkbar, bei denen das Federelement ein Federzapfen ist, der aufrecht stehend auf dem Längsnutenboden angeordnet ist. Alternativ kann das Federelement auch wenigstens ein gegen ein Gaspolster wirkender Federkolben sein, der nach Art einer Gasfeder zur Wirkung kommt.The clamping means pressing the clamping elements radially outward can have spring means, which in turn can expediently have at least one corrugated spring or at least one spring element made of an elastomeric material. This spring element can be an elongated spring body which is inserted lengthways into the longitudinal groove, but embodiments are also conceivable in which the spring element is a spring pin which is arranged upright on the longitudinal groove base. Alternatively, the spring element can also be at least one spring piston which acts against a gas cushion and acts in the manner of a gas spring.

Zumindest der in die Längsnut ragende und durch die Spann- und Abstützfläche begrenzte Teil jedes Schneidelementes weist eine im wesentlichen keilförmige, zu dem Umfang des Werkzeugkörpers hin sich verjüngende Querschnittsgestalt auf. Die Spann- und Abstützfläche können dabei wiederum einen spitzen Winkel solcher Größe aufweisen, daß an den mit ihnen zusammenwirkenden Flächen des Werkzeugkörpers und des Spannelementes, d.h. der Sitz- und der Abstützfläche, eine selbsthemmende Wirkung zustandekommt.At least the part of each cutting element that projects into the longitudinal groove and is delimited by the clamping and supporting surface has an essentially wedge-shaped cross-sectional shape that tapers towards the circumference of the tool body. The clamping and supporting surface can in turn have an acute angle of such a size that on the surfaces of the tool body and the clamping element interacting with them, i.e. the seat and the support surface, a self-locking effect occurs.

In einer bevorzugten Ausführungsform ist das zweischenklige Schneidelement im Querschnitt im wesentlichen L-förmig gestaltet, wobei zumindest einer seiner Schenkel, die sich keilförmig verjüngende Querschnittsgestalt aufweist. Die Spannfläche ist dabei zweckmäßigerweise auf der innenliegenden Seite des zugeordneten Schenkels angeordnet. Um die Materialausnutzung zu erhöhen, kann dabei das als Wendeschneidelement ausgebildete Schneidelement zwei gleichgestaltete Schenkel aufweisen, von denen jeder eine Schneide trägt. Auch ist es vorteilhaft, wenn die Anlagefläche am Umfang des Werkzeugkörpers oder eines mit diesem verbundenen Teils neben der entsprechenden Längsnut angeordnet ist.In a preferred embodiment, the two-legged cutting element has an essentially L-shaped cross section, at least one of its legs having a wedge-shaped cross-sectional shape. The clamping surface is expediently arranged on the inner side of the associated leg. In order to increase the material utilization, the cutting element designed as an indexable cutting element can have two legs of the same design, each of which carries a cutting edge. It is also advantageous if the contact surface is arranged on the circumference of the tool body or a part connected to it next to the corresponding longitudinal groove.

Der Werkzeugkörper kann zumindest in den Au- ßenumfangsbereichen massiv ausgebildet sein, so daß die Längsnuten unmittelbar in das Material des Werkzeugkörpers eingearbeitet sind. Zur Material-und Gewichtsersparung kann es aber insbesondere bei Schneidwerkzeugen für größere Leistungen zweckmäßig sein, wenn die Längsnuten jeweils in länglichen Schneidelemententrägern ausgebildet sind, die mit dem Werkzeugkörper verbunden oder Teile desselben bildend angeordnet sind.The tool body can be solid at least in the outer circumferential areas, so that the longitudinal grooves are machined directly into the material of the tool body. In order to save material and weight, however, it may be expedient, in particular in the case of cutting tools for greater outputs, if the longitudinal grooves are each formed in elongate cutting element carriers which are connected to the tool body or are arranged to form parts thereof.

Bei größerer axialer Länge des Schneidwerkzeuges ist es von Vorteil, wenn der Werkzeugkörper aus einer Anzahl koaxialer, kreisringförmiger, axial miteinander verspannter sowie mit Schneidelementen bestückter Abschnitte besteht, deren Schneidelemente an den Trennfugen der Abschnitte stumpf aneinanderstoßend angeordnet sind, so daß sich über die axiale Länge des Schneidwerkzeuges durchgehende Schneidkanten ergeben.With a greater axial length of the cutting tool, it is advantageous if the tool body consists of a number of coaxial, annular, axially braced sections and equipped with cutting elements, the cutting elements of which are butt-jointed at the parting joints of the sections, so that the axial length of the cutting tool result in continuous cutting edges.

Um nun trotzdem einen Austausch einzelner schadhaft gewordener Schneidelemente von der Außenumfangsseite einzelner Abschnitte dieses Werkzeugkörpers her zu ermöglichen, ist die Anordnung derart getroffen, daß benachbarte Abschnitte an den einander zugewandten Stirnseiten durch Paßelemente drehfest miteinander verbunden sind und zwischen benachbarte Abschnitte in Axialrichtung wirkende Federteile eingefügt sind.In order to enable the replacement of individual defective cutting elements from the outer peripheral side of individual sections of this tool body, the arrangement is such that adjacent sections on the facing end faces are rotatably connected to one another by fitting elements and spring parts acting in the axial direction are inserted between adjacent sections .

Durch diese Ausbildung wird erreicht, daß nach Lösen der axialen Verspannung der einzelnen Abschnitte die zwischen diesen angeordneten Federelemente die Abschnitte an den Trennfugen selbsttätig soweit auseinanderschieben, daß die einzelnen Schneidelemente der Abschnitte stirnseitig voneinander getrennt sind und nach dem Niederdrücken der keilförmigen Spannelemente in der bereits geschilderten Weise aus den zugeordneten Längsnuten des jeweiligen Abschnittes herausgenommen werden können. Bei axial gegeneinander verspannten Abschnitten des Werkzeugkörpers ist dies nicht ohne weiteres möglich, weil auch die Schneidelemente stirnseitig axial gegeneinander verspannt sind.This configuration ensures that after releasing the axial tensioning of the individual sections, the spring elements arranged between them automatically push the sections at the parting lines apart to such an extent that the individual cutting elements of the sections are separated from one another at the end and after the wedge-shaped clamping elements have been depressed in the one already described Can be removed from the associated longitudinal grooves of the respective section. With axially braced sections of the tool body, this is not readily possible because the cutting elements are also axially braced against one another on the end face.

Die Spannmittel können im übrigen auch wenigstens eine mit dem Spannelement und/oder dem Werkzeugkörper oder einem mit diesem verbundenen Teil gekuppelte Spannschraube aufweisen, die das Spannelement radial wach außen zu in den keilförmig sich verjüngenden Raum einpreßt. Solche Spannschrauben können zusätzlich zu den bereits erwähnten Federmitteln vorhanden sein, doch sind auch Ausführungsformen denkbar, bei denen die Spannmittel lediglich durch solche Spannschrauben gebildet sind.The tensioning means can also have at least one tensioning screw coupled to the tensioning element and / or the tool body or a part connected to it, which presses the tensioning element radially awake outward into the wedge-shaped tapering space. Such tensioning screws can be present in addition to the spring means already mentioned, but embodiments are also conceivable in which the tensioning means are only formed by such tensioning screws.

Besonders einfache konstruktive Verhältnisse ergeben sich dabei, wenn jede Spannschraube in eine zum Werkzeugkörperumfang sich öffnende Bohrung des Spannelementes eingesetzt und gegen den Boden der Längsnut abgestützt ist. Infrage kommen aber auch Ausführungsformen, bei denen die Spannschraube in entsprechenden Ausnehmungen oder Bohrungen des Werkzeugkörpers angeordnet von unten her gegen das jeweilige Spannelement drücken oder von der Seite her zugängig in den Werkzeugkörper oder dessen Teile eingesetzt sind.Particularly simple structural relationships result when each clamping screw is inserted into a bore of the clamping element that opens to the circumference of the tool body and is supported against the bottom of the longitudinal groove. However, embodiments are also possible in which the clamping screw, arranged in corresponding recesses or bores in the tool body, press against the respective clamping element from below or are inserted into the tool body or its parts with access from the side.

Abhängig von den Gegebenheiten des jeweiligen Schneidwerkzeuges kann es schließlich noch vorteilhaft sein, wenn die Abstützfläche des Schneidelementes mit der benachbarten Längsnutenseitenwandung im wesentlichen fluchtend oder nur geringfügig über diese in das Nutinnere vorragend angeordnet ist.Depending on the circumstances of the respective cutting tool, it may finally be advantageous if the support surface of the cutting element is arranged in substantially flush alignment with the adjacent longitudinal groove side wall or only slightly protrudes beyond it into the groove interior.

In der Zeichnung sind Ausführungsbeispiele des Gegenstandes der Erfindung dargestellt. Es zeigen Figur 1 ein rundlaufendes Schneidwerkzeug gemäß der Erfindung,im Querschnitt, im Ausschnitt und in schematischer Darstellung, unter Veranschaulichung von vier unterschiedlichen Ausführungsformen der den Spannelementen zugeordneten Federmittel, Figur 2 ein rundlaufendes Schneidwerkzeug gemäß der Erfindung, im Querschnitt, im Ausschnitt und in schematischer Darstellung, unter Veranschaulichung einer abgewandelten Ausführungsform der Schneidelemente, Figur 3 die Anordnung nach Figur 2, unter Veranschaulichung einer anderen Ausführungsform der Schneidelemente in einer entsprechenden Darstellung, Figur 4 einen mehrteiligen Werkzeugkörper eines rundlaufenden Schneidwerkzeuges gemäß der Erfindung, geschnitten längs der Linie IV-IV der Figur 5, in einer Seitenansicht, Figur 5 den Werkzeugkörper nach Figur 4, in einer Seitenansicht, Figur 6 einen Schneidelemententräger zum Einsatz in den Werkzeugkörper nach Fig. 5, in perspektivischer Darstellung und in einem anderen Maßstab, Figur 7 ein aus mehreren Werkzeugkörpern nach Figur 4,5 zusammengesetztes rundlaufendes Schneidwerkzeug, gemäß der Erfindung, in einer Draufsicht, teilweise aufgeschnitten und in schematischer Darstellung, Figur 8 zwei Abschnitte eines rundlaufenden Schneidwerkzeugs gemäß der Erfindung, in perspektivischer schematischer Darstellung, und Figuren 9,10 ein rundlaufendes Schneidwerkzeug gemäß der Erfindung, im Querschnitt, im Ausschnitt und in schematischer Darstellung, unter Veranschaulichung einer abgewandelten Ausführungsform der Schneidelemente sowie ein Spannelement der Anordnung nach Figur 9, in einer Seitenansicht.Exemplary embodiments of the subject matter of the invention are shown in the drawing. 1 shows a rotary cutting tool according to the invention, in cross section, in detail and in a schematic representation, illustrating four different embodiments of the spring means assigned to the clamping elements, FIG. 2 shows a rotary cutting tool according to the invention, in cross section, in detail and in a schematic Representation, illustrating a modified embodiment of the cutting elements, Figure 3 shows the arrangement of Figure 2, illustrating another embodiment of the cutting elements in a corresponding representation, Figure 4 shows a multi-part tool body of a rotary cutting tool according to the invention, cut along the line IV-IV of the 5, in a side view, FIG. 5 the tool body according to FIG. 4, in a side view, FIG. 6 a cutting element carrier for use in the tool body according to FIG. 5, in a perspective view and in another dimension rod, FIG. 7 shows a rotary cutting tool composed of several tool bodies according to FIG. 4.5, according to the invention, in a top view, partially cut open and in a schematic representation, FIG. 8 shows two sections of a rotating cutting tool according to the invention, in a perspective schematic representation, and FIGS 9, 10 shows a rotating cutting tool according to the invention, in cross section, in detail and in a schematic illustration, illustrating a modified embodiment of the cutting elements, and a clamping element of the arrangement according to FIG. 9, in a side view.

Das in den Figuren 1 - 3 jeweils im Ausschnitt dargestellte rundlaufende Schneidwerkzeug weist einen massiven, im wesentlichen hülsen- oder kreisringförmigen Werkzeugkörper 1 auf, wie er im Prinzip in Figur 8 dargestellt ist. Dieser Werkzeugkörper 1 ist dazu bestimmt - insbesondere gemeinsam mit weiteren axial anschließenden, gleichgestalteten Werkzeugkörpern 1 -auf einer Welle drehfest angeordnet zu werden, die endseitig Wellenzapfen trägt, mit denen das Werkzeug in entsprechenden Lagern drehbar gelagert werden kann. Das Schneidwerkzeug dient insbesondere zum Stranggranulieren von Kunststoffen und ist in hervorragender Weise dazu geeignet, auch schwer zu granulierende Kunststoffe, bspw. solche mit Beimischungen von Mineralfasern und dergl., zu verarbeiten.The rotary cutting tool shown in FIGS. 1-3 in detail has a solid, essentially sleeve-shaped or circular tool body 1, as is shown in principle in FIG. This tool body 1 is intended - in particular together with other axially connecting, identical tool bodies 1 - to be arranged in a rotationally fixed manner on a shaft which at the end carries shaft journals with which the tool can be rotatably supported in corresponding bearings. The cutting tool is used in particular for strand pelletizing of plastics and is excellently suitable for processing plastics which are difficult to granulate, for example those with admixtures of mineral fibers and the like.

Der im wesentlichen zylindrische Werkzeugkörper 1 ist an seinem Umfang mit einer Anzahl gleichmäßig verteilt angeordneter Längsnuten 2 ausgebildet, die sich über die gesamte axiale Länge des Werkzeugkörpers 1 erstrecken. Die Längsnuten 2 schließen mit der Drehachse des Werkzeugkörpers 1 einen kleinen Winkel von ca. 2° ein, wie dies in Fig. 7 bei 3 etwas vergrößert dargestellt ist.The essentially cylindrical tool body 1 is formed on its circumference with a number of evenly distributed longitudinal grooves 2, which extend over the entire axial length of the tool body 1. The longitudinal grooves 2 enclose a small angle of approximately 2 ° with the axis of rotation of the tool body 1, as is shown somewhat enlarged in FIG. 7 at 3.

Von jeder der Längsnuten 2 geht seitlich eine Ausnehmung 4 ab, die sich zum Umfang des Werkzeugkörpers 1 hin öffnet und deren Seitenfläche eine Sitzfläche 5 für ein Schneidelement 6, 6a oder 6b bildet, das gemeinsam mit einem im Querschnitt keilförmigen Spannelement 7 in der Längsnut 2 untergebracht ist.A recess 4 extends laterally from each of the longitudinal grooves 2, which opens towards the circumference of the tool body 1 and whose side surface forms a seat surface 5 for a cutting element 6, 6a or 6b, which together with a clamping element 7 which is wedge-shaped in cross section, in the longitudinal groove 2 is housed.

Die leistenartigen Schneidelemente 6, 6a, 6b bestehen vorzugsweise aus Hartmetall, Stellit oder Keramik; sie können ein- oder mehrteilig aufgebaut sein, wobei in dem zuletzt genannten Falle aus Hartmetall oder dergl. bestehende Schneidleisten auf einen entsprechenden Träger aufgebracht, bspw. aufgelötet, sind. Die Schneidelemente 6, 6a, 6b sind grundsätzlich derart in den Werkzeugkörper 1 angeordnet, daß ihre wirksamen Schneidkanten 8 auf einem gemeinsamen Flugkreis laufen.The strip-like cutting elements 6, 6a, 6b preferably consist of hard metal, stellite or ceramic; they can be constructed in one or more parts, in which case cutting bars made of hard metal or the like are applied, for example soldered, to a corresponding carrier. The cutting elements 6, 6a, 6b are basically arranged in the tool body 1 in such a way that their effective cutting edges 8 run on a common flight circle.

Bei der Ausführungsform nach Fig. 1 ist jedes der Schneidelemente 6 im Querschnitt im wesentlichen L-förmig gestaltet. Es ist somit zweischenklig; seine beiden Schenkel sind mit 9 und 10 bezeichnet. Die beiden Schenkel 9,10 sind im Querschnitt jeweils im wesentlichen keilförmig, wobei der in der Längsnut 2 liegende Schenkel 10 eine zu der Umfangsfläche des Werkzeugkörpers 1 hin sich verjüngende Keilform aufweist. Er ist auf der einen Seite durch eine auf der Sitzfläche 5 aufliegende Spannfläche 11 und auf der gegenüberliegenden Seite durch eine Abstützfläche 12 begrenzt, auf die das keilförmige Spannelement 7 einwirkt, das seinerseits gegen die der Abstützfläche 12 gegenüber liegende Seitenfläche 13 der Längsnut 2 abgestützt ist. Mit seinem Schenkel 10 liegt das Schneidelement 6 außerdem auf der Grundfläche 14 der zugeordneten Ausnehmung 4 auf, die damit eine Anschlagfläche für das Schneidelement 6 bildet.In the embodiment according to FIG. 1, each of the cutting elements 6 is essentially L-shaped in cross section. It is therefore two-legged; his two legs are labeled 9 and 10. The two legs 9, 10 are each essentially wedge-shaped in cross-section, the leg 10 lying in the longitudinal groove 2 having a wedge shape tapering towards the peripheral surface of the tool body 1. It is bounded on one side by a clamping surface 11 resting on the seat surface 5 and on the opposite side by a support surface 12 on which the wedge-shaped clamping element 7 acts, which in turn is supported against the side surface 13 of the longitudinal groove 2 opposite the support surface 12 . With its leg 10, the cutting element 6 also lies on the base surface 14 of the associated recess 4, which thus forms a stop surface for the cutting element 6.

Der durch die Abstützfläche 12 jedes Schneidelementes 6 und die gegenüberliegende Längsnutenseitenwand 13 begrenzte Raum ist zum Umfang des Werkzeugkörpers 1 hin keilförmig sich verjüngend ausgebildet. In diesen Raum ist das entsprechend keilförmig geformte, sich in der gleichen Richtung verjüngende Spannelement 7 durch Federmittel eingepreßt, die zwischen der Unterseite des Spannelementes 7 und dem Boden 15 der Längsnut 2 angeordnet sind.The space delimited by the support surface 12 of each cutting element 6 and the opposite longitudinal groove side wall 13 is tapered in a wedge shape towards the circumference of the tool body 1 educated. The corresponding wedge-shaped clamping element 7, which tapers in the same direction, is pressed into this space by spring means which are arranged between the underside of the clamping element 7 and the bottom 15 of the longitudinal groove 2.

Von diesen Federmitteln sind in Fig. 1 vier verschiedene Ausführungsformen veranschaulicht, die alternativ eingesetzt werden können:Of these spring means, four different embodiments are illustrated in FIG. 1, which can be used alternatively:

Bei der am weitesten links dargestellten Längsnut 2 sind die Federmittel durch wenigstens ein aus einem elastomeren Material bestehenden Federelement in Gestalt eines länglichen, zylindrischen Federkörpers 16, der der Länge nach in die Längsnut 2 eingelegt ist, gebildet.In the longitudinal groove 2 shown on the left, the spring means are formed by at least one spring element made of an elastomeric material in the form of an elongated, cylindrical spring body 16, which is inserted lengthways into the longitudinal groove 2.

In der rechts anschließenden Längsnut 2 ist als Federelement eine Well- bzw. Blattfeder 17 eingefügt, während in der rechts darauffolgenden Längsnut 2 als Federmittel wenigstens ein Federkolben 18 angeordnet ist, der mit einem zylindrischen Kolbenhals 19 in einen in dem Werkzeugkörper 1 ausgebildeten gasgefüllten Zylinderraum 20 ragt, der gegen den Kolbenhals über eine entsprechende Dichtwand 21 abgedichtet ist. Der somit gegen ein Gaspolster wirkende Federkolben 18 ist somit grundsätzlich ähnlich einer Gasfeder gestaltet.A corrugated or leaf spring 17 is inserted as the spring element in the longitudinal groove 2 adjoining on the right, while at least one spring piston 18 is arranged in the longitudinal groove 2 following on the right as spring means, which has a cylindrical piston neck 19 in a gas-filled cylinder space 20 formed in the tool body 1 protrudes, which is sealed against the piston neck via a corresponding sealing wall 21. The spring piston 18 thus acting against a gas cushion is thus fundamentally similar to a gas spring.

Bei der ganz rechts veranschaulichten Längsnut sind die Federmittel durch aus elastomerem Material bestehende Federzapfen 22 gebildet, die aufrecht stehend in entsprechende Bohrungen 23 in dem Nutenboden 15 eingesetzt sind.In the longitudinal groove illustrated on the far right, the spring means are formed by spring pins 22 made of elastomeric material, which are inserted upright into corresponding bores 23 in the groove base 15.

Die die Schenkel 10 der Schneidelemente 6 aufnehmenden Ausnehmungen 4 sind in dem Werkzeugkörper 1 derart angeordnet, daß jede Sitzfläche 5 mit ihrer Spur eine Sekante zu einem den Umriß des Werkzeugkörpers 1 darstellenden Kreis ausgebildet ist.Die im Betrieb an den Schneidele-. menten 6 in radialer Richtung angreifenden Fliehkräfte weisen deshalb eine Komponente auf, die rechtwinklig auf der Sitzfläche 5 steht und die bestrebt ist, den Schenkel 10 mit der Spannfläche 11 gegen die Sitzfläche 5 zu drücken. Die Schneidelemente 6 sind durch die schrägen Sitzflächen 5 und die mit diesen zusammenwirkenden, ebenfalls schrägen Spannflächen 11 an dem Werkzeugkörper 1 radial abgestützt.The recesses 4 receiving the legs 10 of the cutting elements 6 are arranged in the tool body 1 such that each seat surface 5 is formed with its track a secant to a circle representing the outline of the tool body 1. elements 6 in the radial direction attacking centrifugal forces therefore have a component that is perpendicular to the seat surface 5 and which strives to press the leg 10 with the clamping surface 11 against the seat surface 5. The cutting elements 6 are supported radially on the tool body 1 by the inclined seating surfaces 5 and the cooperating, likewise inclined clamping surfaces 11.

Die Abstützfläche 12 und die gegenüberliegende Längsnutenseitenwand 13 jeder Längsnut schließen einen eine Selbsthemmung für das keilförmige Spannelement 7 ergebenden spitzen Winkel miteinander ein, dessen Größe im Einzelfall von der an den aufeinanderliegenden Flächen geltenden Materialpaarung abhängt. In ähnlicher Weise begrenzen auch die Spann- und Abstützfläche 11 und 12 jedes Schneidelement 6 einen spitzen Winkel solcher Größe, daß sich ebenfalls eine selbsthemmende Wirkung ergibt.The support surface 12 and the opposite longitudinal groove side wall 13 of each longitudinal groove enclose an acute angle, which results in a self-locking effect for the wedge-shaped clamping element 7, the size of which depends in individual cases on the material pairing that applies to the superimposed surfaces. Similarly, the clamping and support surface 11 and 12 of each cutting element 6 limit an acute angle of such a size that there is also a self-locking effect.

Wie aus Fig. 1 zu ersehen, ist die Spannfläche 11 der im Querschnitt im wesentlichen L-förmigen Schneidelemente 6 auf der innenliegenden Seite des zugeordneten Schenkels 10 angeordnet. Die L-förmige Querschnittsgestalt der Schneidelemente 6 bringt den Vorteil hoher Stabilität der Schneidelemente mit sich, wobei gleichzeitig der in Schneidrichtung an die Schneide 8 anschließende, erfahrungsgemäß besonders hoch beanspruchte Bereich des Umfanges des Werkzeugkörpers 1 durch die Außenfläche des Schenkels 9 des jeweiligen aus Hartmetall etc. bestehenden Schneidelementes gebildet und damit besonders widerstandsfähig ist. In Schneidrichtung vor den Schneidkanten 8 sind in der Umfangsfläche des Werkzeugkörpers 1 schließlich in der üblichen Weise Spannuten 24 ausgebildet.As can be seen from FIG. 1, the clamping surface 11 of the cutting elements 6, which are essentially L-shaped in cross section, is arranged on the inner side of the associated leg 10. The L-shaped cross-sectional shape of the cutting elements 6 brings with it the advantage of high stability of the cutting elements, while at the same time the area of the circumference of the tool body 1 which adjoins the cutting edge 8 in the cutting direction and which, according to experience, is particularly highly stressed, through the outer surface of the leg 9 of the respective hard metal, etc. existing cutting element is formed and is therefore particularly resistant. In the cutting direction in front of the cutting edges 8, flutes 24 are finally formed in the circumferential surface of the tool body 1 in the usual manner.

Die in Fig. 2 veranschaulichte Ausführungsform unterscheidet sich von jener nach Fig. 1 insoweit, als die Schneidelemente 6a als sogenannte Wendeschneidelemente ausgebildet sind. Die beiden Schenkel 9,10 der ansonsten im wesentlichen den Schneidelementen 6 entsprechenden leistenartigen Schneidelemente 6a sind beide gleich gestaltet; jeder von ihnen trägt eine Schneide 8.The embodiment illustrated in FIG. 2 differs from that according to FIG. 1 in that the cutting elements 6a are designed as so-called indexable cutting elements. The two legs 9, 10 of the strip-like cutting elements 6a, which otherwise essentially correspond to the cutting elements 6, are both designed identically; each of them wears a cutting edge 8.

Jede der Ausnehmungen 4 ist mit ihrer Sitzfläche 5 und ihrer Bodenfläche 14 der Gestalt der beiden Schenkel 9,10 entsprechend ausgebildet, wobei aber die Anlagefläche 14a der neben der Längsnut 2 auf dem Umfang des Werkzeugkörpers 1 angeordnet ist. Gleiche Teile sind deshalb mit gleichen Bezugszeichen versehen, womit sich eine nochmalige Erörterung erübrigt.Each of the recesses 4 is designed with its seat 5 and its bottom surface 14 to match the shape of the two legs 9, 10, but the contact surface 14a is arranged next to the longitudinal groove 2 on the circumference of the tool body 1. The same parts are therefore provided with the same reference numerals, so that a repeated discussion is unnecessary.

Bei der Ausführungsform nach Fig. 3 schließlich sind die leistenförmigen Schneidelemente 6b einschenklig mit im wesentlichen keilförmiger Querschnittsgestalt ausgebildet, wobei die die Keilform seitlich begrenzenden Flächen 11, 12 radial nach außen zu gerichtet sich verjüngend angeordnet sind.Finally, in the embodiment according to FIG. 3, the strip-shaped cutting elements 6b are formed in one leg with an essentially wedge-shaped cross-sectional shape, the surfaces 11, 12 which laterally delimit the wedge shape being tapered radially outward.

Während aber bei den Ausführungen nach den Fig. 1,2 das keilförmige Spannelement 7 auf der der Schneidkante 8 abgewandten Seite des Schenkels 10 des Schneidelementes 6 bzw. 6a angeordnet ist, ist bei der Ausführungsform nach Fig. 3 die Anordnung derart getroffen, daß das Spannelement 7 an der die Schneidkante 8 enthaltenden Spannfläche 11 1 des Schneidelementes 6b, d.h. an dessen Vorderseite, angreift.1.2 but the wedge-shaped clamping element 7 is arranged on the side of the leg 10 of the cutting element 6 or 6a facing away from the cutting edge 8, in the embodiment according to FIG. 3 the arrangement is such that the Clamping element 7 on the clamping surface 11 1 of the cutting element 6b containing the cutting edge 8, ie attacks on its front.

Um eines der Schneidelemente 6, 6a, 6b in dem Werkzeugkörper 1 auszutauschen, genügt es, mittels einer geigneten Vorrichtung das Spannelement 7 vom Umfang des Werkzeugkörpers 1 her radial nach innen gegen die Wirkung der Federmittel soweit einzudrücken, daß der Schenkel 10 bzw. das Schneidelement 6b freikommt und aus der Längsnut 2 unbehindert entnommen sowie durch ein neues Schneidelement ersetzt werden kann. Dieses neue Schneidelement kann außerhalb des Werkzeugkörpers 1 maßgenau zugerichtet werden. Es wird bei niedergedrücktem Spannelement 7 einfach in die Ausnehmung 5 soweit eingeschoben, bis es auf der Anschlagfläche 14 aufsteht. Sodann wird das Spannelement 7 freigegeben, das von den Federmitteln in den keilförmigen Raum zwischen den Flächen 12, 13 eingepreßt wird, wodurch das Schneidelement 6, 6a, 6b mit seiner Spannfläche 11 gegen die Sitzfläche 5 des Werkzeugkörpers 1 verspannt wird. Die betriebsmäßig auftretenden Fliehkräfte sind bestrebt, das Spannelement 7 nach außen zu ziehen, wodurch die Spannung der Schneidelement 6, 6a, 6b noch verstärkt wird. Wegen der von der Radialrichtung abweichenden Schräglage der Sitzflächen 5 sind die Schneidelemente gleichzeitig, wie bereits erläutert, radial nach außen zu formschlüssig abgestützt.To replace one of the cutting elements 6, 6a, 6b in the tool body 1, it is sufficient to use a suitable device to press the clamping element 7 radially inward from the circumference of the tool body 1 against the action of the spring means to such an extent that the leg 10 or the cutting element 6b is released and can be freely removed from the longitudinal groove 2 and replaced by a new cutting element. This new cutting element can be tailored outside of the tool body 1. When the clamping element 7 is depressed, it is simply pushed into the recess 5 until it stands on the stop surface 14. Then the clamping element 7 is released, which is pressed by the spring means into the wedge-shaped space between the surfaces 12, 13, whereby the cutting element 6, 6a, 6b is clamped with its clamping surface 11 against the seat surface 5 of the tool body 1. The centrifugal forces that occur during operation endeavor to pull the tensioning element 7 outwards, whereby the tension of the cutting elements 6, 6a, 6b is further increased. Because of the inclined position of the seat surfaces 5 which deviates from the radial direction, the cutting elements are at the same time, as already explained, supported radially outward to form-fit.

Bei der in den Fig. 4 - 7 dargestellten abgewandelten Ausführungsform des neuen Schneidwerkzeugs ist der Werkzeugkörper nach Art eines sogenannten Rotors 100 ausgebildet. Der Rotor 100 besteht aus einer Anzahl von Ringscheiben 30, die in der aus den Fig. 4 und 7 ersichtlichen Weise mittels Spannbolzen 31 axial miteinander verspannt sind. Die Anordnung ist dabei derart getroffen, daß zwischen den beiden außenständigen Ringscheiben 30 Distanzhülsen 32 angeordnet sind, durch die die Spannschrauben 31 verlaufen, die in entsprechende Gewindebohrungen 32' einer mittig angeordneten Nabenscheibe 33 eingeschraubt sind, auf welcher stimseitig zwei weitere Ringscheiben 30 aufliegen. Der Rotor 100 ist auf beiden Stirnseiten durch Abdeckkappen 34 abgedeckt und im übrigen auf eine nicht weiter dargestellte Welle drehfest aufgesetzt.In the modified embodiment of the new cutting tool shown in FIGS. 4-7, the tool body is designed in the manner of a so-called rotor 100. The rotor 100 consists of a number of annular disks 30 which are clamped axially to one another by means of clamping bolts 31 in the manner shown in FIGS. 4 and 7. The arrangement is such that 30 spacer sleeves 32 are arranged between the two external washers, through which the clamping screws 31 run, which are screwed into corresponding threaded bores 32 'of a centrally arranged hub disk 33, on which two further washers 30 rest on the end face. The rotor 100 is covered on both end faces by cover caps 34 and, moreover, is placed on a shaft (not shown) in a rotationally fixed manner.

Die Ringscheiben 30 sind an ihrem Umfang mit randoffenen Nuten 200 versehen, die über die axiale Länge des Rotors 100 miteinander fluchtend angeordnet sind. In die Nuten 200 benachbarter Ringscheiben 30 sind schienen- oder leistenförmige Schneidelemententräger 35 eingesetzt, wie sie im einzelnen in Fig. 6 veranschaulicht sind.The ring disks 30 are provided on their circumference with open-edge grooves 200 which are aligned with one another over the axial length of the rotor 100. Rail-shaped or strip-shaped cutting element carriers 35, as are illustrated in detail in FIG. 6, are inserted into the grooves 200 of adjacent annular disks 30.

Jeder der Schneidelemententräger 35 weist zwei der Form der Nuten 200 angepaßte, im Querschnitt im wesentlichen rechteckige Endflansche 36 auf, die Bohrungen 37 für Befestigungsschrauben 38 haben, welche in entsprechende Gewindebohrungen 39 auf dem Boden der Nuten 200 eingeschraubt sind. In dem Bereich zwischen den Endflanschen 36 ist jeder Schneidelemententräger 35 bei 40 abgeschrägt, am einen freien Durchtritt des erzeugten Granulats zu gewährleisten.Each of the cutting element supports 35 has two end flanges 36 which are substantially rectangular in cross section and which have holes 37 for fastening screws 38 which are screwed into corresponding threaded holes 39 on the bottom of the grooves 200 and are adapted to the shape of the grooves 200. In the area between the end flanges 36, each cutting element carrier 35 is chamfered at 40 to ensure that the granulate produced can pass freely.

Die Schneidelemententräger 35 sind jeweils mit einer durchgehenden Längsnut 2 gestaltet, die in dem Bereich zwischen den Endflanschen 36 die in den Fig. 1 -3 dargestellte Querschnittsgestalt aufweist. In ihr ist das jeweilige Schneidelement 6 (oder 6a bzw. 6b) durch ein keilförmiges Spannelement 7 in der aus den Fig. 1 und 3 ersichtlichen Weise gespannt.The cutting element carriers 35 are each designed with a continuous longitudinal groove 2, which has the cross-sectional shape shown in FIGS. 1-3 in the area between the end flanges 36. In it, the respective cutting element 6 (or 6a or 6b) is clamped by a wedge-shaped clamping element 7 in the manner shown in FIGS. 1 and 3.

Die auf benachbarten Ringscheibenpaaren 30 angeordneten Schneidelemententräger 35 sind mit ihren Schneidelementen 6 stumpf aneinanderstoßend angeordnet, so daß sich über die Länge des Rotors 100 durchgehende Schneidkanten 8 ergeben, die den kleinen Winkel 3 (Fig. 7) mit der Rotordrehachse 41 einschließen.The cutting element carriers 35 arranged on adjacent pairs of annular disks 30 are arranged with their cutting elements 6 butt-abutting, so that continuous cutting edges 8 result over the length of the rotor 100, which include the small angle 3 (FIG. 7) with the rotor axis of rotation 41.

Kegelpaßstifte 42 (Fig. 4) gewährleisten eine exakt winkelgerechte Ausrichtung der Ringscheiben 30 gegeneinander.Taper dowel pins 42 (FIG. 4) ensure an exact angular alignment of the ring disks 30 relative to one another.

Bei der in Fig. 8 schematisch veranschaulichten Ausführungsform besteht das Schneidwerkzeug aus mehreren koaxialen Abschnitten, von denen jeder von einem Werkzeugkörper 1 gebildet ist, wie er anhand der Fig. 1 -3 schon erläutert wurde. Diese Werkzeugkörper 1 sind auf eine gemeinsame, in Fig. 8 nicht weiter dargestellte Welle drehfest aufgesetzt und auf dieser, bspw. durch einen Gewindering, axial verspannt. Zwischen benachbarten, jeweils von einem Werkzeugkörper 1 gebildeten Abschnitten sind achsparallele, zylindrische Paßstifte 44 und diesen zugeordnete Paßbohrungen 45 im Bereiche der aufeinander zuweisenden Stirnflächen angeordnet. Zwischen den Paßstiften 44 sind in entsprechende Bohrungen 46 eingesetzte Druckfedern 47 vorgesehen, die bestrebt sind, die Werkzeugkörper 1 axial auseinander zu drücken.In the embodiment schematically illustrated in FIG. 8, the cutting tool consists of several coaxial sections, each of which is formed by a tool body 1, as has already been explained with reference to FIGS. 1-3. These tool bodies 1 are non-rotatably mounted on a common shaft (not shown in FIG. 8) and axially clamped thereon, for example by a threaded ring. Between adjacent sections, each formed by a tool body 1, axially parallel, cylindrical locating pins 44 and locating holes 45 associated therewith are arranged in the region of the end faces facing one another. Between the dowel pins 44, compression springs 47 are provided in corresponding bores 46, which strive to axially press the tool body 1 apart.

Wenn bei einem aus solchen Abschnitten bestehenden Schneidwerkzeug ein Schneidelement 6 eines der Werkzeugkörper 1 ausgetauscht werden muß, wird die axiale Verspannung der Abschnitte gelöst, mit dem Ergebnis, daß die Druckfedern 47 die die Abschnitte bildenden Werkzeugkörper 1 axial soweit auseinanderdrücken können, daß die Schneidelemente dieser Abschnitte stirnseitig voneinander frei kommen und in der bereits beschriebenen Weise durch Niederdrücken der Spannelemente 7 gelöst und ausgetauscht werden können.If a cutting element 6 of one of the tool bodies 1 has to be exchanged in a cutting tool consisting of such sections, the axial bracing of the sections is released, with the result that the compression springs 47 can axially push apart the tool body 1 forming the sections to such an extent that the cutting elements thereof Sections come free from each other on the end face and can be released and exchanged in the manner already described by depressing the tensioning elements 7.

Selbstverständlich ist der Gedanke, auf diese Weise den Austausch der einzelnen Schneidelemente 6 zu erleichtern, nicht nur bei massiven Werkzeugkörpern 1 anwendbar; er kann auch auf den Rotor 100 nach Fig. 7 übertragen werden, wobei dann zwischen den nicht durch Schneidelemententräger 5 miteinander verbundenen Ringscheiben 30 den Druckfedern 47 entsprechende Federelemente anzuordnen sind.Of course, the idea of facilitating the exchange of the individual cutting elements 6 in this way is not only applicable to solid tool bodies 1; it can also be transferred to the rotor 100 according to FIG. 7, in which case spring elements corresponding to the compression springs 47 are to be arranged between the annular disks 30 which are not connected to one another by cutting element carriers 5.

Schließlich kann die radiale Abstützung der Schneidelemente 6,6a,6b an dem Werkzeugkörper 1 bzw. dem Schneidelementträger 35 auch durch einen Ansatz 50 des Schneidelementes formschlüssig erfolgen, wie dies in Fig. 1 schematisch angedeutet ist.Finally, the radial support of the cutting elements 6, 6a, 6b on the tool body 1 or the cutting element carrier 35 can also take place in a form-fitting manner by means of an attachment 50 of the cutting element, as is schematically indicated in FIG. 1.

Bei der in den Fig. 9,10 dargestellten Ausführungsform ist das im Querschnitt im wesentlichen L-förmig gestaltete Schneidelement 6 im wesentlichen wie in Fig. 1 gestaltet. Gleiche Teile sind auch hier mit gleichen Bezugszeichen bezeichnet und im einzelnen nicht weiter erläutert.In the embodiment shown in FIGS. 9, 10, the cutting element 6, which is essentially L-shaped in cross section, is designed essentially as in FIG. 1. The same parts are denoted here with the same reference numerals and are not explained in detail.

Die Ausnehmung 4 ist in Umfangsrichtung des Werkzeugkörpers 1 so tief, daß der in ihr liegende, zur Umfangsfläche des Werkzeugkörpers 1 hin sich keilförmig verjüngende Schenkel 10 des Schneidelementes 6 im wesentlichen ganz in der Ausnehmung 4 aufgenommen ist. Seine Abstützfläche 12 ragt nur geringfügig über die benachbarte Längsnutseitenwandung in das Innere der Längsnut 2 vor. Bei entsprechender Ausbildung des Spannelementes 7 mit einer seitlich vorspringenden, auf der Abstützfläche 12 aufliegenden Schulter könnte sie auch mit der benachbarten Längsnutenseitenwandung fluchten. Das keilförmige Spannelement 7 weist bei dem dargestellten Ausführungsbeispiel zwei im Abstand angeordnete Bohrungen 52 auf, die sich zum Umfang des Werkzeugkörpers 1 öffnen und von denen jede eine Spannschraube 51 erhält. Die Spannschaube 51 ist in eine Gewindebohrung 53 im Boden der Bohrung 52 eingeschraubt und gegen den Boden 15 der Längsnut 2 abgestützt. Zwischen den Spannschrauben 51 können Federelemente angeordnet sein, wie sie anhand von Fig. 1 im einzelnen erläutert wurden, doch ist es auch möglich, in bestimmten Anwendungsfällen auf diese Federelemente zu verzichten.The recess 4 is so deep in the circumferential direction of the tool body 1 that the leg 10 of the cutting element 6 tapering in a wedge-shaped manner toward the circumferential surface of the tool body 1 is received essentially entirely in the recess 4. Its support surface 12 projects only slightly beyond the adjacent longitudinal groove side wall into the interior of the longitudinal groove 2. With a corresponding design of the tensioning element 7 with a laterally projecting shoulder resting on the support surface 12, it could also be aligned with the adjacent longitudinal groove side wall. In the exemplary embodiment shown, the wedge-shaped clamping element 7 has two bores 52 arranged at a distance, which open to the circumference of the tool body 1 and each of which receives a clamping screw 51. The clamping screw 51 is screwed into a threaded bore 53 in the bottom of the bore 52 and is supported against the bottom 15 of the longitudinal groove 2. Spring elements can be arranged between the tensioning screws 51, as explained in detail with reference to FIG. 1, but it is also possible to dispense with these spring elements in certain applications.

Um ein solches Schneidelement 6 auszutauschen, werden die mit einem Innensechskant versehenen Spannschrauben 51 durch die Bohrung 52 von der Werkzeugkörperumfangsseite aus gelöst, womit sich das Spannelement 7 in der Längsnut 2 nach unten schieben läßt. Damit kommt es von der Abstützfläche 12 des Schneidelementes 6 wegen seiner keilförmigen Gestalt frei, und zwar soweit, daß das Schneidelement 6 mit seinem keilförmigen Schenkel 10 aus der Ausnehmung 4 zum Werkzeugkörperumfang hin herausgenommen werden kann. Nach dem Einsetzen eines neuen Schneidelementes 6 brauchen nur die Spannschrauben 51 angezogen zu werden, die auf dem Längsnutenboden 15 sich abstützend über ihr Gewinde das Spannelement 7 radial nach außen drücken und damit das Schneidelement 6 verklemmen.In order to replace such a cutting element 6, they are provided with an internal hexagon hen clamping screws 51 loosened through the bore 52 from the tool body circumference side, with which the clamping element 7 can be pushed downward in the longitudinal groove 2. Thus, it comes free from the support surface 12 of the cutting element 6 because of its wedge-shaped shape, to the extent that the cutting element 6 with its wedge-shaped leg 10 can be removed from the recess 4 towards the tool body circumference. After the insertion of a new cutting element 6, only the clamping screws 51 need to be tightened, which are supported on the longitudinal groove bottom 15 and press the clamping element 7 radially outward via their thread and thus clamp the cutting element 6.

Wenn zusätzliche Federmittel 16,17,18,22 vorhanden sind, übernehmen diese zunächst die Aufgabe, das Spannelement 7 radial nach außen in die Spannstellung zu drücken, wobei die Spannschrauben 51, die sodann festgezogen werden, noch eine weitere Erhöhung der Spannwirkung und damit eine zusätzliche Sicherung ergeben.If additional spring means 16, 17, 18, 22 are present, these first take on the task of pushing the tensioning element 7 radially outward into the tensioning position, the tensioning screws 51, which are then tightened, still further increasing the tensioning action and thus one result in additional security.

Claims (21)

1. A rotary cutting tool, more particularly for the continuous granulation of plastics, having a cylindrical tool body (1, 100) formed with a number of longitudinal grooves (2) uniformly distributed in the peripheral direction, each of which contains a releasably inserted, strip-like cutting element (6, 6a, 6b) and a clamping element (7) of wedge shaped cross-section which is disposed in the space, tapering in wedge shape in the direction of the periphery of the tool body (1), between a bearing surface (12) of the cutting element and the side wall (13) of the longitudinal groove opposite said bearing surface and has in cross-section a matching wedge shape tapering in the same direction and is pressed radially outwards by clamping means (16; 17; 18; 22) borne in the zone of the bottom (15) of the longitudinal groove into the space tapering in wedge shape, so that the cutting element is clamped via a clamping surface (11) remote from the clamping element against a seating surface (5) in the zone of the longitudinal groove, characterized in that that part of the cutting element which extends into the longitudinal groove in the tool body or in a member (35) connected thereto and is bounded by the clamping and bearing surfaces (11, 12) has a substantially wedge shaped cross-section tapering in the direction of the periphery of the tool body (1, 100) and having a maximum width smaller than the opening width of the longitudinal groove, and the tool body or the member (35) connected thereto has a bearing surface (14, 140) for the cutting element which determines the radial position of the cutting element,
2. A cutting tool according to claim 1, characterized in that the seating surface (5) is disposed to form with its track a secant to a circle representing the contour of the tool body (1).
3. A cutting tool according to claims 1 or 2, characterized in that the bearing surface (12) and the opposite side wall (13) of the longitudinal groove enclose with one another an acute angle producing self-inhibition.
4. A cutting tool according to one of the preceding claims, characterized in that the seating surface (5) is formed in or alongside a recess (4) in the tool body (1) or in a member (35) connected thereto which extends laterally from the longitudinal groove (2) and whose bottom (14) has a bearing for the cutting elements (6, 6a, 6b).
5. A cutting tool according to claims 4 or 5, characterized in that the recess (4) or the tool body (1) has the bearing surface (14; 14a) for the cutting elements (6, 6a, 6b).
6. A cutting tool according to one of the preceding claims, characterized in that the clamping means have spring means (16, 17, 18, 22).
7. A cutting tool according to one of the preceding claims, characterized in that the spring means have at least one spring washer (17).
8. A cutting tool according to claim 6, characterized in that the spring means have at least one spring element (16; 22) made from an elastomeric material.
9. A cutting tool according to claim 8, characterized in that the spring element is an elongate spring member (16) inserted lengthwise into the longitudinal groove (2).
10. A cutting tool according to claim 8, characterized in that the spring element is a spring pin (22) disposed standing upright on the bottom (15) of the longitudinal groove.
11. A cutting tool according to claim 8, characterized in that the spring element is a spring plunger (18) acting against a gas cushion.
12. A cutting tool according to claim 1, characterized in that the clamping and bearing surfaces (11, 12) enclose an acute angle producing a self-inhibition in cooperation with the associated surfaces of the tool body (1) or of a member (35) connected thereto and of the clamping element (7).
13. A cutting tool according to claim 1, characterized in that, the two-armed cutting element (6, 6a) is substantially L-shaped in cross-section and at least one of its arms (10) has the cross-sectional shape tapering in wedge shape.
14. A cutting tool according to claim 1, characterized in that the clamping surface (11) is disposed on the inner side of the associated arm (10).
15. A cutting tool according to claims 5 and 13, characterized in that the bearing surface (14a) is disposed alongside the corresponding longitudinal groove on the periphery of the tool body (1) or of a member (35) connected thereto.
16. A cutting tool according to claims 12 or 14, characterized in that the cutting element (6a), constructed in the form of a turnover cutting element, has two identically shaped arms (9, 10), each of which bears a cutting edge (8).
17. A cutting tool according to one of the preceding claims, characterized in that each of the longitudinal grooves (2) is formed in elongate cutting element carriers (35) which are connected to the tool body (1, 100) or disposed forming parts thereof.
18. A cutting tool according to one of the preceding claims, characterized in that it comprises a number of coaxial circular portions (1) which are clamped axially to one another and equipped with cutting elements (6, 6a, 6b), the cutting elements (6, 6a, 6b) being disposed abutting one another at the parting lines of the portions, adjacent portions (1) are non-rotatably connected to one another by mating elements (44, 45) at the adjacent end faces, and spring members (47) operating in the axial direction are inserted between adjacent portions (1).
19. A cutting tool according to one of the preceding claims, characterized in that the clamping means have at least one tightening screw (51) coupled to the clamping element (7) and/or the tool body (1) or a member connected thereto.
20. A cutting tool according to claim 19, characterized in that each tightening screw (51) is inserted in a bore (52) in the clamping element (7) opening in the direction of the tool body periphery and bears against the bottom of the longitudinal groove (7).
21. A cutting tool according to one of the preceding claims, characterized in that the bearing surface (12) of the cutting element (6, 6a, 6b) is disposed substantially in alignment with the adjacent side wall of the longitudinal groove or projecting only slightly beyond said side wall into the inside of the groove.
EP86115293A 1986-11-05 1986-11-05 Rotating cutter, especially for a plastic granulator Expired - Lifetime EP0266447B1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP86115293A EP0266447B1 (en) 1986-11-05 1986-11-05 Rotating cutter, especially for a plastic granulator
DE8686115293T DE3671605D1 (en) 1986-11-05 1986-11-05 ROTARY CUTTING TOOL, ESPECIALLY FOR STRAND GRANULATING PLASTICS.
AT86115293T ATE53178T1 (en) 1986-11-05 1986-11-05 ROTARY CUTTING TOOL, PARTICULARLY FOR STRAND GRANULATION OF PLASTICS.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP86115293A EP0266447B1 (en) 1986-11-05 1986-11-05 Rotating cutter, especially for a plastic granulator

Publications (2)

Publication Number Publication Date
EP0266447A1 EP0266447A1 (en) 1988-05-11
EP0266447B1 true EP0266447B1 (en) 1990-05-30

Family

ID=8195567

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86115293A Expired - Lifetime EP0266447B1 (en) 1986-11-05 1986-11-05 Rotating cutter, especially for a plastic granulator

Country Status (3)

Country Link
EP (1) EP0266447B1 (en)
AT (1) ATE53178T1 (en)
DE (1) DE3671605D1 (en)

Cited By (1)

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DE102006042255A1 (en) * 2006-09-08 2008-03-27 Komptech Gmbh shredder

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DE3886037D1 (en) * 1988-06-02 1994-01-13 Hench Hans Rotary cutting tool, especially for strand pelletizing of plastics.
DE58905321D1 (en) * 1989-01-03 1993-09-23 Hans Hench CIRCULAR CUTTING TOOL, ESPECIALLY FOR STRAND GRANULATING PLASTICS.
US5042733A (en) * 1990-08-06 1991-08-27 Hans Hench Rotary cutter, particularly for granulating plastic material
EP0956902B1 (en) 1998-05-12 2003-03-26 Holz-, Metall-, Abfall-, Recyclingtechnik GmbH Knife mounting device on a cutter shaft of a disintegrating machine
CN103120977B (en) * 2013-03-27 2014-09-10 湖南朝晖环境科技有限公司 Combined conveniently-detached tool for multi-jaw waste material breaker

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DE930839C (en) * 1951-10-11 1955-07-25 Westfalia Dinnendahl Groeppel Rotor for centrifugal mills
US2747803A (en) * 1952-07-09 1956-05-29 Pettibone Mulliken Corp Hammer rotor for hammermills
NL7015532A (en) * 1970-10-23 1972-04-25
DE2208687B1 (en) * 1972-02-24 1973-06-14 Hombak Maschinenfab Kg Knife shaft for woodworking machines
NL7205104A (en) * 1972-04-14 1973-10-16
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CH584067A5 (en) * 1974-03-15 1977-01-31 Andreas E Dr Hazemag Kg
CA1040072A (en) * 1975-07-14 1978-10-10 Arnold Schmidt Cutter shaft for wood machining apparatus
US4360168A (en) * 1978-12-21 1982-11-23 Conair, Inc. Rotary blade assembly for pelletizer assembly
US4219291A (en) * 1979-03-14 1980-08-26 Hoeh James A Segmented helical rotary cutter and method of making same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006042255A1 (en) * 2006-09-08 2008-03-27 Komptech Gmbh shredder
DE102006042255B4 (en) * 2006-09-08 2014-02-13 Komptech Gmbh shredder

Also Published As

Publication number Publication date
ATE53178T1 (en) 1990-06-15
EP0266447A1 (en) 1988-05-11
DE3671605D1 (en) 1990-07-05

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