EP3241948A1 - Rotary milling cutter with a plurality of interchangeable tool heads and tool head for such a rotary milling cutter - Google Patents

Abstract

The invention discloses a milling tool for road milling, tilling, forestry milling, stone crushers o. The like. Machines. The milling tool has a milling drum (10) rotating about a horizontal axis, which is equipped on its outer circumference with a plurality of interchangeable tool heads (12), at least some of which are designed as flat milling bits (16), each with carbide inserts (18). are provided. The flat milling bits (16) are each interchangeably fixed in retaining seats (20) on the outer circumference of the milling drum (10). Here, flat milling bits (16) slide in sections over an outer contour (22) of the respective holding receptacle (20) and are thereby secured against rotation about a respective longitudinal axis of the flat milling chisel (16). In addition, a chisel shank (26) of each flat milling chisel (16) is provided with an external thread (32) which cooperates with a screwed threaded nut (34) for fixing the flat milling chisel (16) in or on the holding mount (20).

Description

The present invention relates to a milling cutter for road milling, soil milling, forestry milling, stone crushers o. The like., Which has a milling drum rotating about a horizontal axis, which is equipped at its outer periphery with a plurality of interchangeable tool heads, having the features of independent claim 1. The invention also relates to a tool head for a milling drum, which is exchangeably fixable there in a holding receptacle, having the features of the independent claim 9.

There are various variants of soil milling known. A frequently used variant of such ground milling machines are so-called chisel cutters which can be used for milling ground surfaces such as roads, surfaces made of concrete, asphalt or the like surfaces, but also of unpaved surfaces, forest areas, etc. The actual milling process takes place here by means of a horizontal axis of rotation rotating milling drum, which is slowly moved in the horizontal milling direction, which is transverse to the axis of rotation, over the ground, the outside mounted on the milling drum chisel when milling in the direction of travel or feed direction against the milled Beat the floor surface and remove it by a defined amount.

In practice, road or asphalt milling in various embodiments, diameters and widths are known in which the conventional milling with a milling drum with horizontal axis of rotation takes place. Typically, carbide-tipped bits strike the milled ground surface in the direction of advance, while the milling machine that carries and drives the rotating drum slowly advances. The milling performance and the achievable milling depth depend on the design features of the milling machine and the milling drum, including the weight of the milling machine. Optionally, the rotating milling drum can be imprinted with at least slight eccentricity in order thereby to improve and increase its removal rate even at lower milling machine weights.

About the circumference and the width of the rotating milling drum usually chisels are distributed, which are naturally subject to relatively high wear and therefore are replaceable to mount on the milling drum. The milling drums are basically suitable for all variants of such soil cutters, forestry cutters and stone crushers. Different types of soil can be milled with these machines. Here, milling bits with carbide wear surface are available, which are mounted in holders outside on a milling drum. These chisels are usually designed mostly as a round shank chisel. Such so-called. Rundschaftmeißel are usually made of steel, and as a wear protection is a tip made of carbide. In order to ensure a uniform wear of the carbide and to improve in this way the service life of the round shank chisel, the chisel must be able to rotate in a holder around its own longitudinal axis and must not be fixed in one position.

From the WO 2008/077 963 A1 is, for example, a conventional milling machine with rotating milling drum for processing road surfaces known. A variant of such a milling drum with a plurality arranged thereon chisel is also from the DE 102 34 661 A1 known. The DE 10 2013 208 539 A1 also discloses a road milling machine for machining road or ground surfaces.

From the DE 20 1015 101 552 U1 In addition, a generic rotary milling tool with a variety of interchangeable tool heads is known. In this known milling tool each equipped with a round shank cutting tools are inserted into corresponding receptacles on the outer circumference of a rotatable milling drum and bolted there. The drill collar has a central internal thread for receiving a fastening screw, which, however, under unfavorable circumstances, can lead to an undesirable weakening of the drill collar and its failure due to breakage when subjected to very high loads.

For this reason, the primary object of the present invention can be seen to provide a milling tool with replaceable tool heads, which have a mechanically more stable and resistant attachment, which entails less material weakenings on a drill collar and thus a better protection against mechanical Failure at high loads can offer.

This object of the invention is achieved with the objects of the independent claims. Features of advantageous developments emerge from the respective dependent claims.

Thus, the invention proposes to achieve the above objective, a milling cutter for road milling, tilling, forestry, stone crushers or similar machines, wherein the milling tool has a milling drum rotating about a horizontal axis, which is equipped on its preferably cylindrical outer periphery with a plurality of interchangeable tool heads of which at least some are formed as a flat-cutting chisel, each of which is provided with cemented carbide inserts. It has been found in practice that when milling particularly abrasive floors previously used versions of milling drums with this often used round shank chisels can not meet all requirements, since the round shank chisel must be changed frequently due to the pronounced wear, resulting in high operating costs , In the present invention, the cutting tools are designed so that they are provided over a larger area with hard metal and designed as a flat cutting chisel and preferably can be replaced arbitrarily against round shank chisel or chisel. In this context, the contact surfaces of the respective chisel, which come into contact with the ground, equipped with a relatively large-area carbide. However, a chisel in this embodiment must be fixable in a defined position on the milling drum, so that the contact surfaces do not rotate out of engagement with the material to be removed. For this purpose, the bit body in the milling tool according to the invention is designed so that it slides over the outer contour of the existing holder and is thereby secured against rotation.

The attachment to the chisel shaft according to the invention with a screwed nut, which secures the chisel shaft. This mounting variant allows the use of a solid drill collar, which is not weakened by a mounting hole, by an internal thread and / or by a circumferential groove for a snap ring attachment o. Since the notch effects of such fasteners weaken the bit shank particularly in those areas which are exposed to very high loads during operation, chisels thus fastened tend to fail and break under unfavorable operating conditions, whereas the flat milling bits designed in accordance with the invention are relatively resistant to comparable loads. These relationships become particularly clear when the indispensable in the prior art central bore with a bore diameter of typically about eight millimeters and a thread depth of typically about thirty millimeters is considered. These bore and thread dimensions are matched to an M8 bolt typically used for bit attachment (see, for example, those in DE 20 1015 101 552 U1 revealed chisel attachment; there Fig. 2b ), however, lead to a potential weakening of the drill collar and thus also increase the risk of breakage or the risk that the bit can break off at high loads due to failure of this attachment of the milling drum.

In contrast, the inventive back extension of the drill collar, which continues into an external thread provides a significant improvement in stability, since the end of the chisel end extending external thread weakens the chisel shaft in any way. The external thread has the advantage that it can be dimensioned significantly larger than the known from the prior art blind hole thread (see. DE 20 1015 101 552 U1 ). With a typical diameter of the chisel shaft of approximately 20 to 30 mm, it is no problem to provide, for example, an M16 or M20 external thread (with external thread diameters of 16 or 20 mm). The screwed onto it threaded nut with the same thread size (eg M16 or M20), which can be preferably added to a washer for support against a contact surface of the holding support for the bit, moves the complete fastener into a region of the drill collar, which is outside of the breakthrough in the holding receptacle of the milling drum and thus outside of a range of highest voltages in the operation of the milling drum, which can act on the drill collar.

This fastening variant has the significant advantage that the external thread arranged at the back of the bit shaft can be dimensioned largely independently of the diameter of the bit shaft, as long as the external thread is at least slightly smaller in diameter than the bit shaft itself.

In the milling cutter according to the invention, the flat milling bits arranged on the rotating milling drum are each interchangeably fixed in holding receptacles on the outer circumference of the milling drum, wherein the flat milling bits interchangeably inserted in the holding receptacles of the milling drum each push over an outer contour of the holding receptacle and thereby prevent rotation about a respective longitudinal axis of the milling cutter Flat chisel are secured. In addition, it is envisaged that a chisel shank of each flat milling chisel with an external thread is equipped, which cooperates with a screw-threaded nut for fixing the flat cutting chisel in or on the holding receptacle.

In the case of the milling tool according to the invention, the flat milling bits also preferably each have a tool head which is equipped with a carbide insert on the face side. The back of the tool head opens into the chisel shaft, which continues at the end in the external thread. To fix the flat milling chisel in the holding receptacle, a threaded nut is screwed onto this external thread.

The holding receptacles each have an obliquely oriented to the outer periphery of the milling drum breakthrough for receiving the cutter shank, wherein the breakthrough receives the respective chisel shank largely free of play. The term of the aperture oriented obliquely to the outer circumference of the milling drum means, in particular, that the holding receptacle or its longitudinal extension direction has an opening enclosing an acute angle for receiving the tool shank with a tangent on the outer circumference of the milling drum. So that the flat-cutting chisel can not loosen or loosen in the mechanically demanding operation, it makes sense that the openings or receptacles take up the respective chisel shanks largely without play. It may even be useful in the interest of a long service life, when the chisel shanks used under at least slight resistance and pushed or pushed into the openings so that they each have a tight fit, even under temperature or other influences to no loose Leads fortifications.

Since these breakthroughs are conventionally designed for pointed chisel, which should rotate in operation about its longitudinal axis, the breakthrough is usefully shaped hollow cylindrical. In the case of the tool according to the invention, the tool head of the flat-milling chisel at least partially covers the holding receptacle, wherein the tool head can correspond in form-fitting manner to an outer contour of this holding receptacle and can form an anti-twist device with the latter. Preferably, the tool head has at least one lateral flank, which rests positively on an outer surface of the holding receptacle.

Optionally, the flat-cutting bit may be designed symmetrically to its longitudinal axis and accordingly have two lateral flanks, which may fit positively against a flattened outer surface of the holding receptacle. In addition, if there is a constriction between the laterally pulled down flanks, the one to Tip-facing withdrawn portion provides, abuts a located between the lateral surfaces of the holding receptacle surface is created due to the thus created positive engagement of the corresponding contours of the bit head and the holding receptacle a very effective anti-rotation and support against leverage forces and moments occurring during operation.

A variant of the milling tool according to the invention can provide that the flat milling bits are each interchangeably fixed in holding receptacles, which can optionally serve as holding receptacles for round shank chisel or pointed chisel o. In the milling drum used, some or all of the chisels used can optionally be designed as flat milling bits. In principle, each of the flat milling bits used in the milling drum can each have the same fastening type as other applicable chisel variants, such as, for example, round shank chisels.

Since it has been found in practice that the conventionally used round shank bits when milling particularly abrasive floors not only wear hard, but can break out of their attachments to the milling drum, the present invention provides an improved, more stable and resistant variant of chisels for Milling machines, which on the one hand are subject to less wear and on the other hand offer better protection against mechanical failure and material fractures, so that they can offer a longer service life.

The above-mentioned object of the invention is further achieved with the subject-matter of independent claim 9, which defines a replaceable milling cutter tool for a rotating milling drum. The tool with its tool head is interchangeable fixable there in a holding receptacle and is designed as a flat milling chisel, which is provided with a carbide insert. The inventively defined tool can be fixed interchangeable in particular in a holding receptacle of the milling drum, which can optionally serve as a holding receptacle for round shank chisel. In this way, the tool head or the tool in a manner cooperate with the holding receptacle, so that the flat milling tool inserted on the milling drum each pushes over an outer contour of the holding receptacle (bit holder) and is thus secured against rotation about a longitudinal axis. The flat-cutting chisel at least partially overlaps an outer contour of the holding receptacle in a form-fitting manner and is thereby secured against rotation about its longitudinal axis. The chisel shank of the flat milling chisel carries an external thread, which cooperates with a screw-threaded nut for fixing the flat cutting chisel in or on the holding receptacle.

The tool head of the tool according to the invention opens for this purpose on the back in the drill collar, which continues at the end in the external thread, which is provided for fixing the flat milling chisel in the holding receptacle with the threaded nut. In addition, the tool head according to the invention preferably has at least one lateral flank for positive engagement with an outer surface of the holding receptacle.

The thus defined tool for the rotary milling drum equipped with a plurality of bits is preferably formed by a chisel or a flat milling chisel, which correspond to one of the previously described embodiments.

• Fig. 1 zeigt in einer schematischen Ansicht einen Teil einer Frästrommel mit einem dort fixierten Fräsmeißel.
• Fig. 2A und Fig. 2B zeigen in schematischen Perspektivansichten eine Ausführungsvariante eines erfindungsgemäßen Flachfräsmeißels, der in einem Halter befestigt ist.
• Fig. 2C zeigt den Flachfräsmeißel gemäß Fig. 2A und Fig. 2B in einer schematischen Teilschnittdarstellung.

In the following, embodiments of the invention and their advantages with reference to the accompanying figures will be explained in more detail. The proportions of the individual elements to one another in the figures do not always correspond to the actual size ratios, since some shapes are simplified and other shapes are shown enlarged in relation to other elements for better illustration.

• Fig. 1 shows a schematic view of a part of a milling drum with a there fixed milling cutter.
• Fig. 2A and Fig. 2B show in schematic perspective views of an embodiment of a flat milling chisel according to the invention, which is mounted in a holder.
• Fig. 2C shows the flat cutter chisel according to Fig. 2A and Fig. 2B in a schematic partial sectional view.

For the same or equivalent elements of the invention are in the FIGS. 1 as well as in the FIGS. 2A to 2C each used the same reference numerals. In some cases, only such reference numerals are shown in the individual figures for better clarity, which are useful or necessary for the description of the respective figure. The illustrated embodiments are only examples of how the device according to the invention can be designed and do not represent a final limitation.

The Fig. 1 shows in a schematic view a portion of a rotating milling drum 10 having a tool head 12 inserted on the outer circumference for abrading a bottom surface 14. The milling drum 10 rotating about a horizontal axis may for example be part of a tiller, forestry tiller or a stone crusher. With the aforementioned machines different types of soil can be milled. These tool heads 12, of which only one in the Fig. 1 is indicated schematically, are used in greater numbers on the outer circumferential surface of the milling drum 10 and fixed, usually in a uniform distribution over the working width of the milling drum 10 and / or on the outer circumference. According to the present invention, the tool heads 12 are each formed by milling bits 16 and by Flachfräsmeißel 16, which are respectively provided at their engagement surfaces with carbide wear surfaces, as described with reference to the FIGS. 2A to 3C are explained in more detail.

The in the FIGS. 2A to 2C Milling bit 16 or flat milling bit 16 shown has a hard metal wear surface 18 and can be mounted in a holder 20 on the milling drum 10. In practice, such bits 16 are often designed as pointed bits (not shown), while the bit 16 according to the invention is designed as a much more effective and wear-resistant flat milling tool 16. The chisel 16 is made of steel; The tip 18 made of carbide serves as wear protection. With conventional pointed bits (not shown) it is useful to provide uniform wear of the tip's hard metal, which is why such a bit normally rotates about its own axis in its holder and should not be fixed in position. However, it has been shown that these variants are disadvantageous when milling particularly abrasive floors, since the wear and thus the cost is relatively high.

The milling tool 16 according to the invention Fig. 2A . Fig. 2B and Fig. 2C is designed so that it is provided over a larger area with carbide than flat milling chisel 16 is formed and can be inserted into the same holder 20 and in the same holding receptacle 20, as it is also used for conventional pointed chisel. For this purpose, the contact surface of the bit 16, which comes into contact with the bottom 14 ( Fig. 1 ), provided with a larger hard metal stocking 18 (cf., for example Fig. 2A ). However, a bit 16 in this embodiment must be fixed in a position so that it does not rotate in the holder or holding receptacle 20 during its use. For this reason, equipped on its front side with the carbide insert 18 tool head 12 of the flat milling chisel 16 according to the invention is designed so that this slides over the outer contour 22 of the existing holder 20 and is secured by this positive connection against rotation.

The tool head 12 has a collar-like widening 24 in the direction of its cylindrical drill shank 26, wherein on this collar-like widening 24 on two opposite sides each strip-like elongated flanks 28 are arranged, which slide over opposite flat sides of the outer contour 22 of the holder 20 and thereby with this outer contour 22 produce a form fit, which secures the bit 16 against rotation.

As is the partial section of the Fig. 2C can recognize the cylindrical chisel shaft 26 is in the assembled state of the flat cutting chisel 16 in a corresponding hollow cylindrical bore 30 in the holder 20, whose oblique orientation defines the angular positioning and positioning of the flat milling chisel 16 on the outer periphery of the milling drum 10. In addition, the chisel shank 26 of each flat-cutting chisel 16 is provided at the end with an external thread 32, onto which a threaded nut 34 for fixing the flat-milling chisel 16 in or on the holding mount 20 can be screwed.

How it especially the FIGS. 2B and 2C clarify, the attachment of the flat milling chisel 16 takes place at the chisel shaft 26 by means of the threaded nut 34 screwed on the back, which secures the chisel shaft in the opening 30 of the holding mount 20. The illustrated mounting variant allows the use of a solid cutter shank 26, which is not weakened by a mounting hole, by an internal thread and / or by a circumferential groove for a snap ring attachment o. On the other hand, the back extension of the chisel shaft 26 shown in the figures, which continues into the external thread 32, provides high stability since the external thread 32 does not weaken the chisel shaft 26. Rather, the external thread 26 has the advantage that it can be dimensioned significantly larger than, for example, a blind-hole thread known from the prior art, which partially penetrates the tool shank (cf. DE 20 1015 101 552 U1 ). With a typical diameter of the chisel shaft 26 of about 20 to 30 mm, there is no problem in providing an M16 or M20 external thread 32 (with outer thread diameters of 16 or 20 mm, for example). The screwed onto it threaded nut 34 with the same thread size (eg M16 or M20), which may be added preferably a washer 36 for support against a contact surface of the holding receptacle 20 for the bit 16 (see. Fig. 2B, Fig. 2C ) displaces the entire fastener into a portion of the reamer shaft 26 that is outside of the aperture 30 in the retainer receptacle 20 of the milling drum 10, and thus outside of a range of highest stresses in the operation of the milling drum 10 that may act on the bit shank 26.

The fastening variant shown has the significant advantage that the external thread 32 arranged on the rear side of the drill collar 26 can be largely dimensioned independently of the diameter of the drill collar 26 as long as the external thread 32 is at least slightly smaller in diameter than the drill collar 26 itself.

Typical dimensions for the flat milling chisel 16 shown may provide approximately its entire length from the tip 18 to the rear external thread 32 of approximately 100 to 150 mm, in particular of approximately 125 mm. A meaningful measure of the largest diameter of the tool head 12 on the collar-like expander 24 may be approximately at about 50 mm to about 80 mm, in particular at about 65 mm. The length of the tool head 12 from the rear contact surface on the holding receptacle 20 to the hard metal tip 18 may be about 35 mm to about 65 mm, in particular about 50 mm. However, all these dimensions are not to be understood as limiting and, depending on the variant embodiment of the invention, may also be chosen significantly differently.

The invention has been described with reference to the FIGS. 1 and 2A to 2C shown preferred embodiment described. However, it will be apparent to those skilled in the art that modifications or changes may be made to the invention without departing from the scope of the following claims.

Bezuaszeichenliste

10

Milling drum, rotating milling drum

12

tool head

14

Soil, soil surface

16

Chisel, milling chisel, flat chisel

18

Carbide wear surface, tip, chisel tip, carbide, carbide tip

20

Holder, holding holder, holder

22

outer contour

24

collar-like broadening

26

Chisel shank, cylindrical chisel shank

28

Flank, extended flank

30

Drilling, breakthrough

32

external thread

34

threaded nut

36

washer

Claims (12)

Milling tool for road milling, tilling, forestry milling, stone crushers o. The like. Machines which has a milling drum rotating about a horizontal axis (10), which is equipped at its outer periphery with a plurality of interchangeable tool heads (12), of which at least some as a flat milling chisel (16) are formed, which are each provided with hard metal inserts (18), - wherein the flat milling bits (16) are each interchangeably fixed in retaining seats (20) on the outer circumference of the milling drum (10), - wherein the in the holding receptacles (20) of the milling drum (10) interchangeable flat milling chisel (16) each in sections over an outer contour (22) of the holding receptacle (20) push and thereby secured against rotation about a respective longitudinal axis of the Flachfräsmeißels (16) , and - Wherein a chisel shank (26) of each Flachfräsmeißels (16) with an external thread (32) is equipped with a screw-threaded nut (34) for fixing the Flachfräsmeißels (16) in or on the respective holding receptacle (20) on the outer circumference of the milling drum (10) interacts. Milling tool according to Claim 1, in which the flat-milling bits (16) each have a tool head (12) which is equipped with a hard-metal insert (18) at the end, wherein the tool head (12) opens at the rear into the tool shank (26), which terminates in the External thread (32) continues. Milling tool according to Claim 1, in which the external thread (32) located on the back of the drill collar (26) for fixing the flat milling bit (16) in the holding receptacle (20) or in the holding fixture (20) fixed state of the respective flat milling chisel (16) the threaded nut (34) is provided. Milling tool according to Claim 1, 2 or 3, in which the holding receptacle (20) or its direction of longitudinal extent has an opening (30) oriented at an angle to the outer circumference of the milling drum (10) or at an acute angle with a tangent at the outer circumference of the milling drum (10) ) for receiving the cutter shank (26), wherein the opening (30) receives the respective chisel shank (26) largely free of play. Milling tool according to one of claims 1 to 4, wherein the tool head (12) of the Flachfräsmeißels (16) at least partially covers the holding receptacle (20) and / or positively corresponds with an outer contour (22) of this holding receptacle (20) and with this an anti-rotation forms. Milling tool according to claim 5, wherein the tool head has at least one lateral flank (28), which rests positively on an outer surface (22) of the holding receptacle (20). Milling tool according to one of claims 1 to 6, wherein the flat milling bits (16) are each interchangeably fixed in the retaining seats (20), which can optionally serve as retaining seats (20) for round shank chisel. Milling tool according to one of claims 1 to 7, wherein each of the flat milling bits (16) inserted in the milling drum (10) each have the same fastening type as a round shank bit. Tool for a rotating milling drum (10) which is exchangeably fixable there in a holding receptacle (20), and which is designed as a flat milling chisel (16) which is provided with a cemented carbide insert (18), wherein the flat milling chisel (16) at least in sections Outer contour (22) of the holding receptacle (20) engages over a form-fitting manner and is secured against rotation about its longitudinal axis, and wherein a chisel shank (26) of the Flachfräsmeißels (16) carries an external thread (32) with a screw-threaded nut (34) for fixing of the flat cutting bit (16) cooperates in or on the holding receptacle (20). Tool according to claim 9, whose tool head (12) opens into the tool shank (26) at the end, which extends in the external thread (32) at the ends, which is provided with the threaded nut (34) for fixing the flat milling bit (16) in the holding receptacle (20) is. Tool according to claim 9 or 10, the tool head (12) has at least one lateral flank (28) for positive engagement with an outer surface (22) of the holding receptacle (20). Tool according to one of claims 9 to 11, which is replaceable in a holding receptacle (20) of the milling drum (10) can be fixed, which can optionally serve as a holding receptacle (20) for round shank chisel.

Images