EP0548239B1 - Excavating tool tooth - Google Patents

Excavating tool tooth Download PDF

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Publication number
EP0548239B1
EP0548239B1 EP91917196A EP91917196A EP0548239B1 EP 0548239 B1 EP0548239 B1 EP 0548239B1 EP 91917196 A EP91917196 A EP 91917196A EP 91917196 A EP91917196 A EP 91917196A EP 0548239 B1 EP0548239 B1 EP 0548239B1
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EP
European Patent Office
Prior art keywords
hard material
tooth
bars
metal
particles
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EP91917196A
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German (de)
French (fr)
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EP0548239A1 (en
Inventor
Guy Maybon
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Technogenia SA
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Technogenia SA
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Priority to AT9191917196T priority Critical patent/ATE105355T1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
    • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
    • B22F7/08—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools with one or more parts not made from powder
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/28—Small metalwork for digging elements, e.g. teeth scraper bits
    • E02F9/2808—Teeth
    • E02F9/285—Teeth characterised by the material used
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
    • B22F2005/001—Cutting tools, earth boring or grinding tool other than table ware

Definitions

  • the present invention relates to excavation tools such as excavator wheels for mining or dredging cutters.
  • the excavator wheels comprise a drive wheel, pivoting about an axis and driven by means of rotation drive.
  • the periphery of the shovel wheel carries a series of buckets equipped with teeth arranged in substantially radial orientations.
  • Dredging strawberries do not have buckets, and their teeth are distributed around the periphery of a rotating ogival structure.
  • Each tooth comprises a one-piece tooth body structure of metal or mechanically resistant alloy such as steel, having a fixing zone for attachment to the bucket or to the ogival structure, and a working zone for digging the ground.
  • the working area is generally flat in the shape of a shovel, bounded by a leading face oriented in the direction of progression of the wheel periphery or of ogival structure in the preferential direction of rotation, a trailing face or face opposite to the attack face.
  • the leading face and the trailing face are generally flat or slightly curved and are connected by a beveled front facet defining a transverse cutting edge.
  • the transverse cutting edge is substantially parallel to the axis of rotation of the assembly, and the general plane formed by the tooth shovel or work area is generally inclined in the direction of tooth progression in the preferred direction of rotation.
  • the bucket or cutter scrapes, through part of its peripheral zone, into the ground, the teeth biting into the ground through the transverse cutting edge and repelling the material from the leading face. This results in significant wear of the transverse cutting edge and the leading face.
  • a usual solution to increase the service life and efficiency of the teeth is to recharge the outer surface of the attack face and the bevelled front facet to coat them with a layer of molten carbide, by melting a weld bead.
  • a protective hardfacing surface layer a layer produced by fusion with a torch or an electric arc.
  • a deposit can be made consisting of a mixture of fused carbide grains embedded in a fusible matrix.
  • Such reloading of a surface is long and tedious, and produces relatively irregular surfaces, consisting of the juxtaposition of several weld beads side by side.
  • the intermediate zones between two successive beads are most often hollow zones whose metallurgical structure is slightly different from the central structure of the weld beads. This results in a lack of homogeneity of the material forming the protective layer of hard material, which leads to the appearance of preferential wear zones promoting faster wear of the material.
  • such a process is expensive, and requires skilled labor.
  • Dredging teeth with a composite structure comprising a metal tooth body containing inserts made of hard abrasion-resistant material.
  • a prefabricated insert is added in suitable housings of the metal tooth body, in which it is fixed by welding or brazing.
  • the insert in the embodiment of Figures 3 and 4, comprises two intermediate bars each occupying the half height of the tooth.
  • JP-A-62 99 527 describes a tooth for an excavation tool in which prefabricated inserts are formed from sintered carbide, and are joined to the tooth body by brazing.
  • the object of the present invention is in particular to avoid the drawbacks of the known structures of teeth of excavation tools and of their production methods, and firstly proposes a new composite structure of tooth comprising several longitudinal bars of hard material occupying the entire height of the tooth.
  • the new tooth structure is compatible with the presence of protective surface layers of molten hard material, but can also be used in the absence of such a protective surface layer.
  • the invention therefore proposes to produce such a tooth structure by means of a so-called infiltration process.
  • the infiltration process can be implemented in a relatively simple manner, without requiring great dexterity of the user, unlike techniques of recharging with a weld bead, and leads to a reduction in the cost of production.
  • the method avoids the need for a delicate step of welding or brazing an insert.
  • the tooth structure thus obtained is characterized in that the bars of hard material are bonded to the metal of the tooth body by a brazing alloy forming the matrix itself binding the grains hard material between them. This characteristic appears particularly important for obtaining a good cohesion effect between the bars of hard material and the metal forming the tooth body.
  • the molding structures are particularly reduced and simple to produce, since the metal parts of the tooth structure themselves function as a mold.
  • the invention makes it possible to considerably improve the longevity and efficiency properties of an excavation tool tooth, in surprising proportions compared to known techniques, for comparable amounts of hard material. During wear, the tooth remains sharp.
  • the invention therefore makes it possible to obtain better cohesion of the excavation tooth, better hardness of the bars of hard material, and greater ease of production.
  • the tooth for excavation tool according to the invention has a general structure similar to known teeth; however the working area of the tooth according to the invention comprises bars made of a base mixture of hard material grains bonded in a matrix, said bars being embedded in the metal of the tooth body and forming longitudinal bars substantially perpendicular to the transverse cutting edge.
  • the longitudinal bars of hard material form a row of bars inserted into the interstices of a metal comb formed by the rest of the body structure.
  • grain material of hard material advantageously occupies the entire height of the tooth between the leading face and the trailing face.
  • the longitudinal bars of hard material are separated from the front facet by a metal zone, or metal crosspiece.
  • This structure facilitates the production of the tooth by infiltration, since the metal crosspiece then forms a mold part to contain the molten material intended to form the bars.
  • the longitudinal bars of hard material are connected to each other by bridges of hard material of height smaller than the bars and with which they form a plate of hard material constituting the central face face. attack.
  • the front ends of the bars of hard material can advantageously be connected to each other by a crosspiece of hard material of height substantially equal to the height of the bars.
  • an excavation tool such as a dredger for dredging or a shovel wheel for mining generally comprises a rotary support structure 1, rotatably mounted on a drive axis 2 and solicited by means for driving in rotation along a preferential axis of rotation represented by the arrow 3.
  • the periphery 4 of the rotary supporting structure carries teeth such as tooth 5, in generally radial orientations slightly inclined in the direction of direction 3 preferential rotation, as shown in the figure.
  • the teeth are all normally identical.
  • the tooth 5 comprises a leading face 6 oriented towards the preferred direction of rotation 3, an opposite trailing face 7, and a front facet 8 defining a transverse cutting edge 9.
  • the transverse cutting edge 9 is substantially parallel to the axis of rotation 2 of the wheel.
  • the tooth 5 is shown in more detail in Figures 2 to 4.
  • Figures 2 to 4 show only the outer surface of the tooth, which can be a traditional tooth or a tooth according to the present invention.
  • an excavation tool tooth according to the invention comprises a tooth body structure of metal or mechanically resistant alloy such as steel, having a fixing zone 10 for the attachment to the drive wheel structure, and a work area 11 for digging the ground.
  • the attachment zone 10 may be of the traditional type, and has no particular effect as regards the present invention.
  • the invention relates to work area 11.
  • the working area 11 is generally flat in the form of a shovel bounded by the leading face 6, the trailing face 7, the front facet 8 and two lateral edges 12 and 13.
  • the leading face 6 and the trailing face 7 are generally flat and slightly curved, possibly parallel to each other.
  • the front facet 8 is inclined at a bevel.
  • the tooth thus has a transverse cutting edge 9.
  • Traditional teeth generally have layers of hard material coating such as grain-based layers. molten tungsten carbide embedded in a metal matrix. The leading face 6, the front facet 8 and the side edges 12 and 13 are covered with a protective layer of hard material.
  • the structure according to the invention is particularly characterized by the presence and the shape of hard material zones embedded in the metal structure of the working zone 11.
  • hard material zones are apparent for example in the embodiment of FIGS. 5 to 7: in FIG. 5, five rectangular zones 14, 15, 16, 17 and 18 appear respectively on the leading face 6.
  • the hard material consisting of a mixture based on grains of hard material linked in a matrix, comes flush with the attack face 6 along the five rectangular zones, of longitudinal axis, regularly spaced from one another.
  • the rectangular areas come close to the transverse cutting edge 9, without however touching the edge.
  • similar rectangular zones 19, 20, 21, 22 and 23 appear on the trailing face 7 shown in FIG. 7.
  • the respective zones such as zone 17 in FIG. 5 and zone 22 in the FIG. 7 are the visible faces of a bar 24 (FIG. 8) made of hard material inserted in a slot passing through the metal forming the basic structure of the working area 11.
  • Figures 8 to 10 show the tooth of Figures 5 to 7, according to different transverse and longitudinal sections.
  • Figure 8 is a longitudinal section, along a plane perpendicular to the leading face 6 and cutting the bar of hard material 24 of Figure 9 corresponding to the surfaces 17 of Figure 5 and 22 of Figure 7.
  • the material of the bar 24 is laterally limited by two intermediate metal beams 25 and 26, by the base 27 of the metal structure of the working area, and by a metal end cross member 28.
  • the material of the bar 24 is flush with the face of attack 6 to form the rectangular area 17, and is flush with the trailing face 7 to form the rectangular area 22.
  • the metal part of the working area 11 has a series of longitudinal slots separated by side members, for example six side members 25, 26, 29, 30, 31 and 32 defining five slots for receiving five bars 24, 33 , 34, 35 and 36.
  • the longitudinal slots are filled with hard abrasion-resistant material such as tungsten carbide or the like.
  • the metal beams are all connected on the one hand to the base of the metal structure 27 and on the other hand to the front metal cross member 28.
  • the outer faces of the tooth are not covered with a wear-resistant protective layer based on hard material.
  • the presence of internal zones of hard material such as the bar 24 is sufficient to considerably delay the wear of the tooth.
  • FIGS. 11 to 13 The structure shown in Figures 11 to 13 is similar to that of Figures 8 to 10: the internal structure is identical; the only difference is the presence of a protective outer layer 100 of hard material, such as grains of molten tungsten carbide bonded by a metal matrix, the outer face of said protective layer forming the leading face 6, the front facet 8 and the side edges 12 and 13.
  • a protective outer layer 100 of hard material such as grains of molten tungsten carbide bonded by a metal matrix
  • FIGS. 14 to 16 The embodiment shown in FIGS. 14 to 16 is similar to that of FIGS. 11 to 13, and differs therefrom by the fact that the metal crosspiece 28 is eliminated.
  • the metal beams such as the beams 25 and 26 have free anterior ends which do not meet, and the space 24 is an open slot.
  • the metal beams thus form a sort of comb, the interstices of which are occupied by a row of bars made of hard material.
  • the hard material filling the interstices such that the space 24 propagates to the protective layer 100, the outer face of which forms the front cutting facet 8.
  • the same internal tooth structure may be used, devoid of a protective layer. 100 outdoor.
  • the structure is similar to that of the embodiment of FIGS. 14 to 16. It differs therefrom by the fact that, in the anterior zone of the side edges 12 and 13, the thickness of the protective layer 100 of hard material is increased. These zones in fact constitute zones of preferential wear, subject to wear stresses greater than those undergone by the other working parts of the tooth. It has been found that a slight increase in the thickness of the protective layer in these two lateral parts leads to a significant increase in the longevity of the tooth.
  • FIGS. 20 to 22 differs from the previous embodiments in that bridges of hard material are provided to connect the successive internal bars of hard material of the tooth.
  • the metal structure of the tooth comprises a metal base 27 to which the intermediate beams 25, 26, 29 and 30 are connected as well as two lateral beams 31 and 32.
  • the front ends of the side rails 31 and 32 are connected by the metal cross member 28.
  • the metal intermediate beams 25, 26, 29 and 30 have free anterior ends set back from the metal cross member 28.
  • the hard material thus forms the longitudinal bars 24, 33, 34, 35 and 36, and the front ends of the bars are connected to each other by a cross member 37 of hard material.
  • the crosspiece 37 of hard material can advantageously occupy the entire height of the active tooth part, that is to say the entire distance separating the leading face 6 and the trailing face 7, as shown in FIG. 20.
  • the metal cross member 28 wears out fairly quickly, and reveals the cross member 37 made of hard material which prevents wear.
  • the metal side rails 31 and 32 wear out fairly quickly, and then reveal the lateral bars of hard material 33 and 36, which prevent wear.
  • the longitudinal bars of hard material are connected to each other by bridges of hard material of height smaller than the bars and with which they form a plate of hard material constituting the central part of the face d 'attack 6.
  • the longitudinal bars of hard material 24 and 33 are connected by the bridge 38.
  • Figure 20 is a section along the longitudinal plane DD of Figure 21, and represents the longitudinal section of this same bridge 38.
  • the bridges 39, 40 and 41 connect two by two the other longitudinal bars of hard material.
  • the intermediate metal beams have a lower height than the total height of the active tooth part, so that the hard material covers the intermediate longitudinal bars on the leading face 6 of the tooth.
  • the bars of hard material can have a thickness of 4 to 15 approximately millimeters, and be separated by metal zones or metal beams whose thickness is approximately 4 to 15 millimeters.
  • the thickness is defined as the dimension in a direction parallel to the transverse cutting edge 9.
  • the length of the bars of hard material is substantially equal to the length of the maximum admissible wear area of the tooth.
  • the hard material constituting the longitudinal bars may advantageously contain grains of molten tungsten carbide, preferably spheroidal grains free of angular zones. Improved anti-wear characteristics are obtained by using a mixture of grains of different calibers, some of the grains of molten tungsten carbide having a diameter equal to or greater than 2 millimeters.
  • the blank 42 is such that the intermediate metal beams 25, 26, 29 and 30 are set back from the leading face 6 defined by the end beams 31 and 32.
  • the hard material 45 fills the slots 43 and covers the intermediate beams 25, 26, 29 and 30 to form a plate of infiltrated hard material 47, shown in FIG. 27, forming the central zone of the attack face 6.
  • the front ends of the end rails 31 and 32 are connected to each other by a metal cross member such as the cross member 28 shown in Figure 20, while the intermediate side members 25, 26, 29 and 30 have a free end separated from the cross member 28 by an interval.
  • the hard material 45 fills said gap separating the free ends of the intermediate beams and the metal cross member 28, to form a cross of hard material 37 such as shown in Figures 20 and 21.
  • the method is compatible with a subsequent step during which a surface coating 100 of hard material can be produced on the leading face 6 and the front facet 8, as shown in FIGS. 11 to 16.
  • the surface coating 100 of material hard can for example be made by welding with a torch or an electric arc of a weld bead, according to conventional methods of reloading by welding.
  • the present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof contained in the field of claims below. It is possible in particular, without departing from the scope of the invention, to provide a number of bars of hard material other than five, sections of bars different from the rectangular section, non-planar shapes of leading face and trailing face of tooth.

Abstract

The tooth according to the invention is composed, in the usual manner, of a mounting area (10) and a working area (11). The steel working area (11) comprises longitudinal bars made of a hard material (14-18). Said bars are inserted in the steel and snugly contact the tooth's cutting face. The presence of the rods made of a hard material substantially increases the tooth's service life. The bars are produced by infiltration.

Description

La présente invention concerne les outils d'excavation tels que les roues-pelles pour exploitation minière ou les fraises de dragage.The present invention relates to excavation tools such as excavator wheels for mining or dredging cutters.

Les roues-pelles comprennent une roue d'entraînement, pivotant autour d'un axe et entraînée par des moyens d'entraînement en rotation. La périphérie de la roue-pelle porte une série de godets équipés de dents disposées selon des orientations sensiblement radiales. Les fraises de dragage ne comportent pas de godets, et leurs dents sont réparties en périphérie d'une structure ogivale rotative. Chaque dent comprend une structure de corps de dent monobloc en métal ou alliage mécaniquement résistant tel que l'acier, présentant une zone de fixation pour la solidarisation au godet ou à la structure ogivale, et une zone de travail pour creuser le sol. La zone de travail est généralement plate en forme de pelle, limitée par une face d'attaque orientée dans le sens de progression de la périphérie de roue ou de structure ogivale dans le sens de rotation préférentielle, une face de fuite ou face opposée à la face d'attaque. La face d'attaque et la face de fuite sont généralement planes ou peu incurvées et se raccordent par une facette frontale en biseau définissant une arête transversale de coupe. Lorsque la dent est montée sur le godet ou la structure ogivale, l'arête transversale de coupe est sensiblement parallèle à l'axe de rotation de l'ensemble, et le plan général formé par la pelle de dent ou zone de travail est généralement incliné en direction du sens de progression de la dent dans le sens de rotation préférentielle.The excavator wheels comprise a drive wheel, pivoting about an axis and driven by means of rotation drive. The periphery of the shovel wheel carries a series of buckets equipped with teeth arranged in substantially radial orientations. Dredging strawberries do not have buckets, and their teeth are distributed around the periphery of a rotating ogival structure. Each tooth comprises a one-piece tooth body structure of metal or mechanically resistant alloy such as steel, having a fixing zone for attachment to the bucket or to the ogival structure, and a working zone for digging the ground. The working area is generally flat in the shape of a shovel, bounded by a leading face oriented in the direction of progression of the wheel periphery or of ogival structure in the preferential direction of rotation, a trailing face or face opposite to the attack face. The leading face and the trailing face are generally flat or slightly curved and are connected by a beveled front facet defining a transverse cutting edge. When the tooth is mounted on the bucket or the ogival structure, the transverse cutting edge is substantially parallel to the axis of rotation of the assembly, and the general plane formed by the tooth shovel or work area is generally inclined in the direction of tooth progression in the preferred direction of rotation.

Lors du fonctionnement, le godet ou la fraise gratte, par une partie de sa zone périphérique, dans le sol, les dents mordant dans le sol par l'arête transversale de coupe et repoussant la matière par la face d'attaque. Il en résulte une usure importante de l'arête transversale de coupe et de la face d'attaque.During operation, the bucket or cutter scrapes, through part of its peripheral zone, into the ground, the teeth biting into the ground through the transverse cutting edge and repelling the material from the leading face. This results in significant wear of the transverse cutting edge and the leading face.

Une solution habituelle pour augmenter la durée de vie et l'efficacité des dents est de recharger la surface extérieure de la face d'attaque et de la facette frontale en biseau pour les revêtir d'une couche de carbure fondu, par fusion d'un cordon de soudure.A usual solution to increase the service life and efficiency of the teeth is to recharge the outer surface of the attack face and the bevelled front facet to coat them with a layer of molten carbide, by melting a weld bead.

Bien que ce procédé augmente sensiblement la durée de vie de la dent, on constate que l'usure, relativement lente en début d'utilisation lorsque la matière dure recouvre encore la facette frontale, devient beaucoup plus rapide lorsque la matière dure recouvrant la facette frontale a elle-même été détériorée par l'usure. La dent ne peut être utilisée que tant que sa zone de travail n'a pas été réduite en longueur dans des proportions trop importantes, définissant la zone d'usure maximale admissible de la dent.Although this process appreciably increases the life of the tooth, it can be seen that wear, relatively slow at the start of use when the hard material still covers the front facet, becomes much faster when the hard material covering the facet front was itself deteriorated by wear. The tooth can only be used until its working area has been reduced in length in too large proportions, defining the maximum admissible wear area of the tooth.

En particulier, à partir du moment où la facette frontale a perdu sa couche protectrice de matière dure, l'usure devient beaucoup plus rapide, malgré l'existence d'une couche de matière dure sur la face d'attaque de la dent.In particular, from the moment the front facet has lost its protective layer of hard material, wear becomes much faster, despite the existence of a layer of hard material on the leading face of the tooth.

Un autre inconvénient des structures connues est qu'elles nécessitent la réalisation d'une couche superficielle protectrice de rechargement dur, couche réalisée par fusion au chalumeau ou à l'arc électrique. Par exemple on peut réaliser un dépôt constitué d'un mélange de grains de carbure fondu noyés dans une matrice fusible. Un tel rechargement d'une surface est long et fastidieux, et produit des surfaces relativement irrégulières, constituées de la juxtaposition de plusieurs cordons de soudure côte à côte. Les zones intermédiaires entre deux cordons successifs constituent le plus souvent des zones en creux dont la structure métallurgique est légèrement différente de la structure centrale des cordons de soudure. Il en résulte un manque d'homogénéité de la matière formant la couche protectrice en matière dure, ce qui entraîne l'apparition de zones préférentielles d'usure favorisant une usure plus rapide de la matière. En outre, un tel procédé est onéreux, et requiert une main d'oeuvre qualifiée.Another disadvantage of the known structures is that they require the production of a protective hardfacing surface layer, a layer produced by fusion with a torch or an electric arc. For example, a deposit can be made consisting of a mixture of fused carbide grains embedded in a fusible matrix. Such reloading of a surface is long and tedious, and produces relatively irregular surfaces, consisting of the juxtaposition of several weld beads side by side. The intermediate zones between two successive beads are most often hollow zones whose metallurgical structure is slightly different from the central structure of the weld beads. This results in a lack of homogeneity of the material forming the protective layer of hard material, which leads to the appearance of preferential wear zones promoting faster wear of the material. In addition, such a process is expensive, and requires skilled labor.

On connaît également des dents de dragage à structure composite, comportant un corps de dent métallique contenant des inserts en matière dure antiabrasion. Ainsi, dans le document US-A-3 805 423, un insert préfabriqué est rapporté dans des logements appropriés du corps métallique de dent, dans lesquels il est fixé par soudage ou brasage. L'insert, sur le mode de réalisation des figures 3 et 4, comprend deux barreaux intermédiaires occupant chacun la demi hauteur de la dent.Dredging teeth with a composite structure are also known, comprising a metal tooth body containing inserts made of hard abrasion-resistant material. Thus, in document US-A-3 805 423, a prefabricated insert is added in suitable housings of the metal tooth body, in which it is fixed by welding or brazing. The insert, in the embodiment of Figures 3 and 4, comprises two intermediate bars each occupying the half height of the tooth.

Le document US-A-4 052 802 enseigne également de prévoir un insert préfabriqué et rapporté dans le corps de dent. L'insert est pris en sandwich entre des plaques métalliques de surface, entre lesquelles il est assemblé par brasage. Ainsi, l'insert n'occupe pas toute la hauteur de la dent. Il n'y a aucune suggestion, dans ce document, pour remplacer les plaques métalliques par une matière à grains de matériau dur.Document US-A-4,052,802 also teaches to provide a prefabricated insert added to the tooth body. The insert is sandwiched between metal surface plates, between which it is assembled by brazing. Thus, the insert does not occupy the entire height of the tooth. There is no suggestion in this document to replace the metal plates with hard grain material.

Dans le document FR-A-2 373 500, un outil pour excavation est réalisé en prévoyant des plaques de couverture en carbure fritté sur un corps en acier. Le corps en acier est coulé autour des plaques de couverture. Il n'y a aucune suggestion, dans ce document, pour remplacer le corps intérieur en acier par une matière à grains de matériau dur. Il en résulterait, d'ailleurs, une grande fragilité de la dent.In document FR-A-2 373 500, an excavation tool is produced by providing cover plates of sintered carbide on a steel body. The steel body is cast around the cover plates. There is no suggestion in this document to replace the inner steel body with a hard grain material. It would result, moreover, a great brittleness of the tooth.

Les structures et procédés de réalisation décrits dans les documents US-A-4 052 802 et FR-A-2 373 500 ne sont pas compatibles entre eux. En effet, la réalisation d'une dent à insert intérieur à grains de matériau dur selon le document US-A-4 052 802 s'effectue par assemblage de plusieurs sous-ensembles par brasure, tandis que le document FR-A-2 373 500 prévoit un tel assemblage par surmoulage. L'homme du métier n'est donc pas incité à combiner l'enseignement de ces deux documents.The structures and production methods described in documents US-A-4,052,802 and FR-A-2,373,500 are not compatible with one another. In fact, the production of a tooth with an internal insert with grains of hard material according to document US-A-4,052,802 is carried out by assembling several sub-assemblies by brazing, while document FR-A-2,373 500 provides for such assembly by overmolding. Those skilled in the art are therefore not encouraged to combine the teaching of these two documents.

Dans le document US-A-3 286 379, des doigts de matériau dur sont réalisés par coulée d'un matériau dur dans des rainures longitudinales du corps métallique de dent. Le document JP-A-62 99 527 décrit une dent pour outil d'excavation dans laquelle des inserts préfabriqués sont formés à partir de carbure fritté, et sont assemblés au corps de dent par brasage.In document US Pat. No. 3,286,379, fingers of hard material are produced by pouring hard material into longitudinal grooves of the metal tooth body. JP-A-62 99 527 describes a tooth for an excavation tool in which prefabricated inserts are formed from sintered carbide, and are joined to the tooth body by brazing.

Il apparaît que ces structures connues à inserts longitudinaux ne procurent pas les résultats attendus d'efficacité et de longévité. On constate en effet une usure encore assez rapide de la dent, notamment par effritement des barreaux de matériau dur. Les barreaux de matériau dur, qui n'occupent pas toute la hauteur de la dent, ne procurent pas une augmentation suffisante de longévité de la dent, et leur procédé de fabrication ne permet pas une cohésion suffisante des parties d'une telle structure hétérogène.It appears that these known structures with longitudinal inserts do not provide the expected results of efficiency and longevity. There is indeed still a fairly rapid wear of the tooth, in particular by erosion of the bars of hard material. The bars of hard material, which do not occupy the entire height of the tooth, do not provide a sufficient increase in longevity of the tooth, and their manufacturing process does not allow sufficient cohesion of the parts of such a heterogeneous structure.

La présente invention a notamment pour objet d'éviter les inconvénients des structures connues de dents d'outils d'excavation et de leurs procédés de réalisation, et propose tout d'abord une nouvelle structure composite de dent comportant plusieurs barreaux longitudinaux de matériau dur occupant toute la hauteur de la dent. La nouvelle structure de dent est compatible avec la présence de couches superficielles de protection en matière dure fondue, mais peut également être utilisée en l'absence d'une telle couche superficielle de protection.The object of the present invention is in particular to avoid the drawbacks of the known structures of teeth of excavation tools and of their production methods, and firstly proposes a new composite structure of tooth comprising several longitudinal bars of hard material occupying the entire height of the tooth. The new tooth structure is compatible with the presence of protective surface layers of molten hard material, but can also be used in the absence of such a protective surface layer.

Mais l'un des problèmes est que, par les procédés habituels de brasage ou de soudage, il est délicat ou difficile d'insérer et de solidariser correctement des barreaux occupant toute la hauteur de la dent, sans perturber les propriétés mécaniques de la matière anti-abrasion constituant les barreaux. L'invention résoud cette difficulté par un procédé nouveau d'infiltration sur l'ébauche de dent elle-même.But one of the problems is that, by the usual methods of soldering or welding, it is difficult or difficult to insert and securely securing bars occupying the entire height of the tooth, without disturbing the mechanical properties of the abrasion-resistant material constituting the bars. The invention solves this difficulty by a new method of infiltration on the tooth blank itself.

L'invention propose donc de réaliser une telle structure de dent au moyen d'un procédé dit d'infiltration. Le procédé d'infiltration peut être mis en oeuvre de manière relativement simple, sans nécessiter une grande dextérité de l'utilisateur, contrairement aux techniques de rechargement par cordon de soudure, et conduit à une diminution du coût de production. Le procédé évite de recourir à une étape délicate de soudage ou de brasage d'un insert.The invention therefore proposes to produce such a tooth structure by means of a so-called infiltration process. The infiltration process can be implemented in a relatively simple manner, without requiring great dexterity of the user, unlike techniques of recharging with a weld bead, and leads to a reduction in the cost of production. The method avoids the need for a delicate step of welding or brazing an insert.

Lorsqu'on utilise un tel procédé d'infiltration, la structure de dent ainsi obtenue se caractérise par le fait que les barreaux de matériau dur sont liés au métal du corps de dent par un alliage de brasage formant la matrice elle-même liant les grains de matériau dur entre eux. Cette caractéristique apparaît particulièrement importante pour obtenir un bon effet de cohésion entre les barreaux de matériau dur et le métal formant le corps de dent.When using such an infiltration process, the tooth structure thus obtained is characterized in that the bars of hard material are bonded to the metal of the tooth body by a brazing alloy forming the matrix itself binding the grains hard material between them. This characteristic appears particularly important for obtaining a good cohesion effect between the bars of hard material and the metal forming the tooth body.

Lors de la mise en oeuvre d'un tel procédé d'infiltration, les structures de moulage sont particulièrement réduites et simples à réaliser, car les parties métalliques de la structure de dent font elles-mêmes fonction de moule.During the implementation of such an infiltration process, the molding structures are particularly reduced and simple to produce, since the metal parts of the tooth structure themselves function as a mold.

L'invention permet d'améliorer considérablement les propriétés de longévité et d'efficacité d'une dent d'outil d'excavation, dans des proportions étonnantes par rapport aux techniques connues, pour des quantités de matériau dur comparables. En cours d'usure, la dent reste coupante.The invention makes it possible to considerably improve the longevity and efficiency properties of an excavation tool tooth, in surprising proportions compared to known techniques, for comparable amounts of hard material. During wear, the tooth remains sharp.

Enfin, on diminue sensiblement le risque de casse ou d'effritement du revêtement et des barreaux de matériau dur, risque que l'on rencontre souvent dans les dents connues.Finally, the risk of breakage or crumbling of the coating and of the bars of hard material is appreciably reduced, a risk which is often encountered in known teeth.

L'invention permet donc d'obtenir une meilleure cohésion de la dent d'excavation, une meilleure dureté des barreaux de matériau dur, et une plus grande facilité de réalisation.The invention therefore makes it possible to obtain better cohesion of the excavation tooth, better hardness of the bars of hard material, and greater ease of production.

Pour atteindre ces objets ainsi que d'autres, la dent pour outil d'excavation selon l'invention présente une structure générale similaire aux dents connues ; toutefois la zone de travail de la dent selon l'invention comprend des barreaux constitués d'un mélange à base de grains de matériau dur liés dans une matrice, lesdits barreaux étant noyés dans le métal du corps de dent et formant des barreaux longitudinaux sensiblement perpendiculaires à l'arête transversale de coupe. Les barreaux longitudinaux en matériau dur forment une rangée de barreaux insérés dans les interstices d'un peigne métallique constitué par le reste de la structure de corps. Dans les parties de section transversale comprenant les barreaux longitudinaux à grains de matériau dur, de la matière à grains de matériau dur occupe avantageusement toute la hauteur de la dent entre la face d'attaque et la face de fuite.To achieve these and other objects, the tooth for excavation tool according to the invention has a general structure similar to known teeth; however the working area of the tooth according to the invention comprises bars made of a base mixture of hard material grains bonded in a matrix, said bars being embedded in the metal of the tooth body and forming longitudinal bars substantially perpendicular to the transverse cutting edge. The longitudinal bars of hard material form a row of bars inserted into the interstices of a metal comb formed by the rest of the body structure. In the cross-sectional parts comprising the longitudinal bars with grains of hard material, grain material of hard material advantageously occupies the entire height of the tooth between the leading face and the trailing face.

Selon une possibilité, les barreaux longitudinaux en matériau dur sont séparés de la facette frontale par une zone métallique, ou traverse métallique. Cette structure facilite la réalisation de la dent par infiltration, puisque la traverse métallique forme alors une partie de moule pour contenir le matériau en fusion destiné à former les barreaux.According to one possibility, the longitudinal bars of hard material are separated from the front facet by a metal zone, or metal crosspiece. This structure facilitates the production of the tooth by infiltration, since the metal crosspiece then forms a mold part to contain the molten material intended to form the bars.

Selon un mode de réalisation particulier, les barreaux longitudinaux en matériau dur sont reliés les uns aux autres par des ponts de matériau dur de hauteur plus petite que les barreaux et avec lesquels ils forment une plaque de matériau dur constituant la partie centrale de face d'attaque. Dans ce cas, les extrémités antérieures des barreaux en matériau dur peuvent avantageusement être reliées les unes aux autres par une traverse en matériau dur de hauteur sensiblement égale à la hauteur des barreaux.According to a particular embodiment, the longitudinal bars of hard material are connected to each other by bridges of hard material of height smaller than the bars and with which they form a plate of hard material constituting the central face face. attack. In this case, the front ends of the bars of hard material can advantageously be connected to each other by a crosspiece of hard material of height substantially equal to the height of the bars.

D'autres objets, caractéristiques et avantages de la présente invention ressortiront de la description suivante de modes de réalisation particuliers, faite en relation avec les figures jointes, parmi lesquelles :

  • la figure 1 est une vue en coupe transversale schématique d'une fraise de dragage ;
  • la figure 2 est une vue de dessus d'une dent, montrant la face d'attaque ;
  • la figure 3 est une vue de côté de la dent de la figure 2 ;
  • la figure 4 est une vue de dessous de la dent de la figure 2, montrant la face de fuite ;
  • les figures 5 à 7 montrent respectivement la face d'attaque, la vue de profil et la face de fuite d'une dent selon un autre mode de réalisation de l'invention ;
  • la figure 8 est une coupe longitudinale en vue de côté selon le plan A-A de la figure 9 ;
  • la figure 9 est une vue de dessus de la dent de la figure 5, en coupe longitudinale selon le plan B-B de la figure 8 ;
  • la figure 10 est une coupe transversale selon le plan C-C de la figure 9 ;
  • les figures 11, 12 et 13 sont des vues similaires des figures 8, 9 et 10 respectivement dans un second mode de réalisation de l'invention ;
  • les figures 14, 15 et 16 sont des vues similaires des figures 8, 9 et 10 dans un troisième mode de réalisation de l'invention ;
  • les figures 17, 18 et 19 sont des vues similaires des figures 8, 9 et 10 respectivement pour un troisième mode de réalisation de l'invention ;
  • les figures 21 et 22 sont des vues similaires des figures 9, 10 respectivement pour un quatrième mode de réalisation selon l'invention, la figure 20 étant une coupe longitudinale selon le plan D-D de la figure 21 ; et
  • les figures 23 à 27 illustrent les étapes d'un procédé de réalisation de dents selon l'invention par infiltration.
Other objects, characteristics and advantages of the present invention will emerge from the following description of particular embodiments, given in relation to the attached figures, among which:
  • Figure 1 is a schematic cross-sectional view of a dredging cutter;
  • Figure 2 is a top view of a tooth, showing the leading face;
  • Figure 3 is a side view of the tooth of Figure 2;
  • Figure 4 is a bottom view of the tooth of Figure 2 showing the trailing face;
  • Figures 5 to 7 respectively show the leading face, the side view and the trailing face of a tooth according to another embodiment of the invention;
  • Figure 8 is a longitudinal section in side view along the plane AA of Figure 9;
  • Figure 9 is a top view of the tooth of Figure 5, in longitudinal section along the plane BB of Figure 8;
  • Figure 10 is a cross section along the plane CC of Figure 9;
  • Figures 11, 12 and 13 are similar views of Figures 8, 9 and 10 respectively in a second embodiment of the invention;
  • Figures 14, 15 and 16 are similar views of Figures 8, 9 and 10 in a third embodiment of the invention;
  • Figures 17, 18 and 19 are similar views of Figures 8, 9 and 10 respectively for a third embodiment of the invention;
  • Figures 21 and 22 are similar views of Figures 9, 10 respectively for a fourth embodiment according to the invention, Figure 20 being a longitudinal section along the plane DD of the Figure 21; and
  • Figures 23 to 27 illustrate the steps of a method of producing teeth according to the invention by infiltration.

Dans le mode de réalisation schématiquement illustré sur la figure 1, un outil d'excavation tel qu'une fraise pour dragage ou une roue-pelle pour exploitation minière comprend généralement une structure porteuse rotative 1, montée rotative sur un axe 2 d'entraînement et sollicitée par des moyens d'entraînement en rotation selon un axe de rotation préférentielle représenté par la flèche 3. La périphérie 4 de la structure porteuse rotative porte des dents telles que la dent 5, selon des orientations généralement radiales légèrement inclinées en direction du sens 3 de rotation préférentielle, comme le représente la figure. Les dents sont toutes normalement identiques. La dent 5 comprend une face d'attaque 6 orientée vers le sens de rotation préférentielle 3, une face de fuite 7 opposée, et une facette frontale 8 définissant une arête transversale de coupe 9. L'arête transversale de coupe 9 est sensiblement parallèle à l'axe de rotation 2 de la roue.In the embodiment schematically illustrated in FIG. 1, an excavation tool such as a dredger for dredging or a shovel wheel for mining generally comprises a rotary support structure 1, rotatably mounted on a drive axis 2 and solicited by means for driving in rotation along a preferential axis of rotation represented by the arrow 3. The periphery 4 of the rotary supporting structure carries teeth such as tooth 5, in generally radial orientations slightly inclined in the direction of direction 3 preferential rotation, as shown in the figure. The teeth are all normally identical. The tooth 5 comprises a leading face 6 oriented towards the preferred direction of rotation 3, an opposite trailing face 7, and a front facet 8 defining a transverse cutting edge 9. The transverse cutting edge 9 is substantially parallel to the axis of rotation 2 of the wheel.

La dent 5 est représentée plus en détail sur les figures 2 à 4. Les figures 2 à 4 ne montrent que la surface extérieure de la dent, qui peut être une dent traditionnelle ou une dent selon la présente invention.The tooth 5 is shown in more detail in Figures 2 to 4. Figures 2 to 4 show only the outer surface of the tooth, which can be a traditional tooth or a tooth according to the present invention.

Comme le représentent les figures 2 à 4, une dent d'outil d'excavation selon l'invention comprend une structure de corps de dent en métal ou alliage mécaniquement résistant tel que l'acier, présentant une zone de fixation 10 pour la solidarisation à la structure de roue d'entraînement, et une zone de travail 11 pour creuser le sol. La zone de fixation 10 peut-être de type traditionnel, et n'a pas d'effet particulier pour ce qui concerne la présente invention. L'invention s'intéresse à la zone de travail 11.As shown in FIGS. 2 to 4, an excavation tool tooth according to the invention comprises a tooth body structure of metal or mechanically resistant alloy such as steel, having a fixing zone 10 for the attachment to the drive wheel structure, and a work area 11 for digging the ground. The attachment zone 10 may be of the traditional type, and has no particular effect as regards the present invention. The invention relates to work area 11.

La zone de travail 11 est généralement plate en forme de pelle limitée par la face d'attaque 6, la face de fuite 7, la facette frontale 8 et deux chants latéraux 12 et 13. La face d'attaque 6 et la face de fuite 7 sont généralement planes et peu incurvées, éventuellement parallèles l'une à l'autre. La facette frontale 8 est inclinée en biseau. La dent présente ainsi une arête transversale de coupe 9.The working area 11 is generally flat in the form of a shovel bounded by the leading face 6, the trailing face 7, the front facet 8 and two lateral edges 12 and 13. The leading face 6 and the trailing face 7 are generally flat and slightly curved, possibly parallel to each other. The front facet 8 is inclined at a bevel. The tooth thus has a transverse cutting edge 9.

Les dents traditionnelles comportent généralement des couches de revêtement en matériau dur telles que des couches à base de grains de carbure de tungstène fondu noyés dans une matrice métallique. La face d'attaque 6, la facette frontale 8 et les chants latéraux 12 et 13 sont recouverts d'une couche protectrice en matériau dur.Traditional teeth generally have layers of hard material coating such as grain-based layers. molten tungsten carbide embedded in a metal matrix. The leading face 6, the front facet 8 and the side edges 12 and 13 are covered with a protective layer of hard material.

La structure selon l'invention se caractérise particulièrement par la présence et la forme de zones de matériau dur noyées dans la structure métallique de la zone de travail 11. De telles zones de matériau dur sont apparentes par exemple dans le mode de réalisation des figures 5 à 7 : sur la figure 5, on voit apparaître, sur la face d'attaque 6, cinq zones rectangulaires respectivement 14, 15, 16, 17 et 18. La matière dure, constituée d'un mélange à base de grains de matériau dur liés dans une matrice, vient en affleurement de la face d'attaque 6 selon les cinq zones rectangulaires, d'axe longitudinal, régulièrement espacées les unes par rapport aux autres. Les zones rectangulaires viennent à proximité de l'arête transversale de coupe 9, sans toutefois toucher l'arête. De même, des zones similaires rectangulaires 19, 20, 21, 22 et 23 apparaissent sur la face de fuite 7 représentée sur la figure 7. En réalité, les zones respectives telles que la zone 17 de la figure 5 et la zone 22 de la figure 7 sont les faces apparentes d'un barreau 24 (figure 8) constitué de matière dure inséré dans une fente traversant le métal formant la structure de base de la zone de travail 11.The structure according to the invention is particularly characterized by the presence and the shape of hard material zones embedded in the metal structure of the working zone 11. Such hard material zones are apparent for example in the embodiment of FIGS. 5 to 7: in FIG. 5, five rectangular zones 14, 15, 16, 17 and 18 appear respectively on the leading face 6. The hard material, consisting of a mixture based on grains of hard material linked in a matrix, comes flush with the attack face 6 along the five rectangular zones, of longitudinal axis, regularly spaced from one another. The rectangular areas come close to the transverse cutting edge 9, without however touching the edge. Likewise, similar rectangular zones 19, 20, 21, 22 and 23 appear on the trailing face 7 shown in FIG. 7. In reality, the respective zones such as zone 17 in FIG. 5 and zone 22 in the FIG. 7 are the visible faces of a bar 24 (FIG. 8) made of hard material inserted in a slot passing through the metal forming the basic structure of the working area 11.

Les figures 8 à 10 représentent la dent des figures 5 à 7, selon différentes coupes transversales et longitudinales. Ainsi, la figure 8 est une coupe longitudinale, selon un plan perpendiculaire à la face d'attaque 6 et coupant le barreau de matière dure 24 de la figure 9 correspondant aux surfaces 17 de la figure 5 et 22 de la figure 7. La matière dure du barreau 24 est limitée latéralement par deux longerons métalliques intermédiaires 25 et 26, par la base 27 de la structure métallique de zone de travail, et par une traverse métallique d'extrémité 28. La matière du barreau 24 affleure sur la face d'attaque 6 pour former la zone rectangulaire 17, et affleure sur la face de fuite 7 pour former la zone rectangulaire 22.Figures 8 to 10 show the tooth of Figures 5 to 7, according to different transverse and longitudinal sections. Thus, Figure 8 is a longitudinal section, along a plane perpendicular to the leading face 6 and cutting the bar of hard material 24 of Figure 9 corresponding to the surfaces 17 of Figure 5 and 22 of Figure 7. The material of the bar 24 is laterally limited by two intermediate metal beams 25 and 26, by the base 27 of the metal structure of the working area, and by a metal end cross member 28. The material of the bar 24 is flush with the face of attack 6 to form the rectangular area 17, and is flush with the trailing face 7 to form the rectangular area 22.

Dans ce mode de réalisation, la partie métallique de zone de travail 11 comporte une série de fentes longitudinales séparées par des longerons, par exemple six longerons 25, 26, 29, 30, 31 et 32 définissant cinq fentes pour recevoir cinq barreaux 24, 33, 34, 35 et 36. Les fentes longitudinales sont remplies de matière dure anti-abrasion telle que le carbure de tungstène ou similaire. Les longerons métalliques sont tous reliés d'une part à la base de structure métallique 27 et d'autre part à la traverse métallique antérieure 28.In this embodiment, the metal part of the working area 11 has a series of longitudinal slots separated by side members, for example six side members 25, 26, 29, 30, 31 and 32 defining five slots for receiving five bars 24, 33 , 34, 35 and 36. The longitudinal slots are filled with hard abrasion-resistant material such as tungsten carbide or the like. The metal beams are all connected on the one hand to the base of the metal structure 27 and on the other hand to the front metal cross member 28.

Dans ce mode de réalisation, les faces extérieures de la dent ne sont pas recouvertes d'une couche de protection anti-usure à base de matériau dur. La présence des zones internes de matériau dur telles que le barreau 24 suffit à retarder considérablement l'usure de la dent.In this embodiment, the outer faces of the tooth are not covered with a wear-resistant protective layer based on hard material. The presence of internal zones of hard material such as the bar 24 is sufficient to considerably delay the wear of the tooth.

La structure représentée sur les figures 11 à 13 est similaire de celles des figures 8 à 10 : la structure interne est identique ; la seule différence est la présence d'une couche extérieure protectrice 100 de matériau dur, tels que des grains de carbure de tungstène fondu liés par une matrice métallique, la face extérieure de ladite couche protectrice formant la face d'attaque 6, la facette frontale 8 et les chants latéraux 12 et 13. L'aspect extérieur d'une telle dent est identique à celui représenté sur les figures 2 à 4.The structure shown in Figures 11 to 13 is similar to that of Figures 8 to 10: the internal structure is identical; the only difference is the presence of a protective outer layer 100 of hard material, such as grains of molten tungsten carbide bonded by a metal matrix, the outer face of said protective layer forming the leading face 6, the front facet 8 and the side edges 12 and 13. The external appearance of such a tooth is identical to that shown in FIGS. 2 to 4.

Le mode de réalisation représenté sur les figures 14 à 16 est similaire à celui des figures 11 à 13, et en diffère par le fait que l'on supprime la traverse métallique 28. Dans ce cas, les longerons métalliques tels que les longerons 25 et 26 comportent des extrémités antérieures libres qui ne se rejoignent pas, et l'espace 24 est une fente ouverte. Les longerons métalliques forment ainsi une sorte de peigne, dont les interstices sont occupés par une rangée de barreaux en matériau dur. La matière dure remplissant les interstices tels que l'espace 24 se propage jusqu'à la couche protectrice 100 dont la face extérieure forme la facette frontale de coupe 8. En variante, on peut utiliser la même structure interne de dent, dépourvue de couche protectrice 100 extérieure.The embodiment shown in FIGS. 14 to 16 is similar to that of FIGS. 11 to 13, and differs therefrom by the fact that the metal crosspiece 28 is eliminated. In this case, the metal beams such as the beams 25 and 26 have free anterior ends which do not meet, and the space 24 is an open slot. The metal beams thus form a sort of comb, the interstices of which are occupied by a row of bars made of hard material. The hard material filling the interstices such that the space 24 propagates to the protective layer 100, the outer face of which forms the front cutting facet 8. As a variant, the same internal tooth structure may be used, devoid of a protective layer. 100 outdoor.

Dans le mode de réalisation des figures 17 à 19, la structure est similaire à celle du mode de réalisation des figures 14 à 16. Elle en diffère par le fait que, dans la zone antérieure des chants latéraux 12 et 13, l'épaisseur de la couche protectrice 100 de matière dure est augmentée. Ces zones constituent en effet des zones d'usure préférentielle, soumises à des contraintes d'usure supérieures à celles subies par les autres parties de travail de la dent. On a constaté qu'une faible augmentation d'épaisseur de couche protectrice dans ces deux parties latérales conduit à augmenter sensiblement la longévité de la dent.In the embodiment of FIGS. 17 to 19, the structure is similar to that of the embodiment of FIGS. 14 to 16. It differs therefrom by the fact that, in the anterior zone of the side edges 12 and 13, the thickness of the protective layer 100 of hard material is increased. These zones in fact constitute zones of preferential wear, subject to wear stresses greater than those undergone by the other working parts of the tooth. It has been found that a slight increase in the thickness of the protective layer in these two lateral parts leads to a significant increase in the longevity of the tooth.

Le mode de réalisation des figures 20 à 22 diffère des modes de réalisation précédents en ce que des ponts de matière dure sont prévus pour relier les barreaux successifs internes de matière dure de la dent. Comme dans le mode de réalisation des figures 8 à 10, la structure métallique de la dent comprend une base métallique 27 à laquelle se raccordent les longerons intermédiaires 25, 26, 29 et 30 ainsi que deux longerons latéraux 31 et 32. Les extrémités antérieures des longerons latéraux 31 et 32 sont reliées par la traverse 28 métallique. Les longerons intermédiaires métalliques 25, 26, 29 et 30 comportent des extrémités antérieures libres en retrait de la traverse 28 métallique. La matière dure forme ainsi les barreaux longitudinaux 24, 33, 34, 35 et 36, et les extrémités antérieures des barreaux sont reliées les unes aux autres par une traverse 37 de matière dure. La traverse 37 de matière dure peut avantageusement occuper toute la hauteur de la partie active de dent, c'est-à-dire toute la distance séparant la face d'attaque 6 et la face de fuite 7, comme le représente la figure 20. Dans ce cas, lors de l'utilisation, la traverse métallique 28 s'use assez rapidement, et laisse apparaître la traverse 37 en matière dure qui s'oppose à l'usure. De même, les longerons latéraux 31 et 32 métalliques s'usent assez rapidement, et laissent ensuite apparaître les barreaux latéraux de matière dure 33 et 36, qui s'opposent à l'usure.The embodiment of FIGS. 20 to 22 differs from the previous embodiments in that bridges of hard material are provided to connect the successive internal bars of hard material of the tooth. As in the embodiment of FIGS. 8 to 10, the metal structure of the tooth comprises a metal base 27 to which the intermediate beams 25, 26, 29 and 30 are connected as well as two lateral beams 31 and 32. The front ends of the side rails 31 and 32 are connected by the metal cross member 28. The metal intermediate beams 25, 26, 29 and 30 have free anterior ends set back from the metal cross member 28. The hard material thus forms the longitudinal bars 24, 33, 34, 35 and 36, and the front ends of the bars are connected to each other by a cross member 37 of hard material. The crosspiece 37 of hard material can advantageously occupy the entire height of the active tooth part, that is to say the entire distance separating the leading face 6 and the trailing face 7, as shown in FIG. 20. In this case, during use, the metal cross member 28 wears out fairly quickly, and reveals the cross member 37 made of hard material which prevents wear. Likewise, the metal side rails 31 and 32 wear out fairly quickly, and then reveal the lateral bars of hard material 33 and 36, which prevent wear.

Dans ce même mode de réalisation, les barreaux longitudinaux en matériau dur sont reliés les uns aux autres par des ponts de matériau dur de hauteur plus petite que les barreaux et avec lesquels ils forment une plaque de matériau dur constituant la partie centrale de la face d'attaque 6. Ainsi, comme le représente la figure 22 en coupe transversale, les barreaux longitudinaux de matière dure 24 et 33 sont reliés par le pont 38. La figure 20 est une coupe selon le plan D-D longitudinal de la figure 21, et représente la coupe longitudinale de ce même pont 38. Les ponts 39, 40 et 41 relient deux à deux les autres barreaux longitudinaux de matière dure. En d'autres termes, les longerons métalliques intermédiaires ont une hauteur plus faible que la hauteur totale de la partie active de dent, de sorte que la matière dure recouvre les barreaux longitudinaux intermédiaires sur la face d'attaque 6 de la dent.In this same embodiment, the longitudinal bars of hard material are connected to each other by bridges of hard material of height smaller than the bars and with which they form a plate of hard material constituting the central part of the face d 'attack 6. Thus, as shown in Figure 22 in cross section, the longitudinal bars of hard material 24 and 33 are connected by the bridge 38. Figure 20 is a section along the longitudinal plane DD of Figure 21, and represents the longitudinal section of this same bridge 38. The bridges 39, 40 and 41 connect two by two the other longitudinal bars of hard material. In other words, the intermediate metal beams have a lower height than the total height of the active tooth part, so that the hard material covers the intermediate longitudinal bars on the leading face 6 of the tooth.

Dans tous les modes de réalisation qui ont été décrits, les barreaux en matériau dur peuvent avoir une épaisseur de 4 à 15 millimètres environ, et être séparés par des zones métalliques ou longerons métalliques dont l'épaisseur est de 4 à 15 millimètres environ. L'épaisseur est définie comme étant la dimension selon une direction parallèle à l'arête transversale de coupe 9. La longueur des barreaux en matériau dur est sensiblement égale à la longueur de la zone d'usure maximale admissible de la dent. La matière dure constituant les barreaux longitudinaux peut avantageusement contenir des grains de carbure de tungstène fondu, de préférence des grains sphéroïdaux exempts de zones anguleuses. Des caractéristiques anti-usure améliorées sont obtenues en utilisant un mélange de grains de différents calibres, certains des grains de carbure de tungstène fondu présentant un diamètre égal ou supérieur à 2 millimètres.In all the embodiments which have been described, the bars of hard material can have a thickness of 4 to 15 approximately millimeters, and be separated by metal zones or metal beams whose thickness is approximately 4 to 15 millimeters. The thickness is defined as the dimension in a direction parallel to the transverse cutting edge 9. The length of the bars of hard material is substantially equal to the length of the maximum admissible wear area of the tooth. The hard material constituting the longitudinal bars may advantageously contain grains of molten tungsten carbide, preferably spheroidal grains free of angular zones. Improved anti-wear characteristics are obtained by using a mixture of grains of different calibers, some of the grains of molten tungsten carbide having a diameter equal to or greater than 2 millimeters.

Selon l'invention, le procédé préféré représenté sur les figures 23 à 27, pour réaliser les zones internes de matière dure telles que les barreaux longitudinaux, comprend les étapes suivantes :

  • a) selon la figure 23, réaliser une ébauche 42 en métal ou alliage, comprenant la zone de fixation 10 et la partie métallique de zone de travail 11, ladite partie métallique de zone de travail comportant une série de fentes longitudinales 43 débouchant sur la face d'attaque 6 et sur la face de fuite 7 et séparées par des longerons 25, 26, 29, 30, 31, 32 ;
  • b) selon la figure 24, disposer ladite ébauche 42 sur un support 44 avec sa face d'attaque 6 au dessus et en orientation sensiblement horizontale ;
  • c) selon la figure 25, remplir lesdites fentes longitudinales 43 avec des particules de matière dure anti-abrasion 45 telle que le carbure de tungstène fondu ou similaire, en vibrant l'ensemble, de sorte que les particules viennent au maximum en appui contre les parois des fentes et sont jointives les unes aux autres ;
  • d) selon la figure 25, préparer une quantité suffisante d'un alliage approprié 46 sous forme adaptée pour assurer une répartition ultérieure de l'alliage au cours d'une phase de fusion ultérieure, l'alliage étant un alliage de brasage susceptible de mouiller les particules de matière dure 45 et la matière formant l'ébauche 42 et de fondre à une température inférieure à la température de fusion de l'ébauche 42 et du support 44 ;
  • e) selon la figure 26, chauffer l'ensemble à une température supérieure à la température de fusion de l'alliage 46 et inférieure à la température de fusion de l'ébauche 42 et du support 44, pour assurer l'infiltration de l'alliage en fusion entre les particules de matière dure 45 ;
  • f) selon la figure 27, laisser refroidir et séparer la pièce obtenue de son support.
According to the invention, the preferred method shown in FIGS. 23 to 27, for producing the internal zones of hard material such as the longitudinal bars, comprises the following steps:
  • a) according to FIG. 23, make a blank 42 of metal or alloy, comprising the fixing zone 10 and the metal part of the work zone 11, said metal part of the work zone comprising a series of longitudinal slots 43 opening onto the face 6 and on the trailing face 7 and separated by side members 25, 26, 29, 30, 31, 32;
  • b) according to FIG. 24, placing said blank 42 on a support 44 with its leading face 6 above and in substantially horizontal orientation;
  • c) according to FIG. 25, filling said longitudinal slots 43 with particles of hard abrasion-resistant material 45 such as molten tungsten carbide or the like, vibrating the assembly, so that the particles come to bear as much as possible against the walls of the slots and are joined to each other;
  • d) according to FIG. 25, preparing a sufficient quantity of an appropriate alloy 46 in a form suitable for ensuring a subsequent distribution of the alloy during a subsequent melting phase, the alloy being a brazing alloy capable of wetting the particles of hard material 45 and the material forming the blank 42 and melt at a temperature below the melting temperature of the blank 42 and the support 44;
  • e) according to FIG. 26, heat the assembly to a temperature higher than the melting temperature of the alloy 46 and lower than the melting temperature of the blank 42 and the support 44, to ensure the infiltration of the molten alloy between the hard material particles 45;
  • f) according to FIG. 27, allow to cool and separate the part obtained from its support.

Dans le mode de réalisation décrit en relation avec les figures 23 à 27, l'ébauche 42 est telle que les longerons métalliques intermédiaires 25, 26, 29 et 30 sont en retrait de la face d'attaque 6 définie par les longerons extrêmes 31 et 32. De cette façon, lors de l'étape de remplissage et d'infiltration de la figure 25, la matière dure 45 remplit les fentes 43 et recouvre les longerons intermédiaires 25, 26, 29 et 30 pour constituer une plaque de matière dure infiltrée 47, représentée sur la figure 27, formant la zone centrale de la face d'attaque 6.In the embodiment described in relation to FIGS. 23 to 27, the blank 42 is such that the intermediate metal beams 25, 26, 29 and 30 are set back from the leading face 6 defined by the end beams 31 and 32. In this way, during the filling and infiltration step of FIG. 25, the hard material 45 fills the slots 43 and covers the intermediate beams 25, 26, 29 and 30 to form a plate of infiltrated hard material 47, shown in FIG. 27, forming the central zone of the attack face 6.

Selon une variante, les extrémités antérieures des longerons extrêmes 31 et 32 sont reliées l'une à l'autre par une traverse métallique telle que la traverse 28 représentée sur la figure 20, tandis que les longerons intermédiaires 25, 26, 29 et 30 comportent une extrémité libre séparée de la traverse 28 par un intervalle. De cette façon, lors de l'étape de remplissage et d'infiltration illustrée par la figure 25, la matière dure 45 remplit ledit intervalle séparant les extrémités libres des longerons intermédiaires et la traverse métallique 28, pour former une traverse de matière dure 37 telle que représentée sur les figures 20 et 21.Alternatively, the front ends of the end rails 31 and 32 are connected to each other by a metal cross member such as the cross member 28 shown in Figure 20, while the intermediate side members 25, 26, 29 and 30 have a free end separated from the cross member 28 by an interval. In this way, during the filling and infiltration step illustrated in FIG. 25, the hard material 45 fills said gap separating the free ends of the intermediate beams and the metal cross member 28, to form a cross of hard material 37 such as shown in Figures 20 and 21.

Le procédé est compatible avec une étape ultérieure au cours de laquelle on peut réaliser un revêtement superficiel 100 de matière dure sur la face d'attaque 6 et la facette frontale 8, comme le représentent les figures 11 à 16. Le revêtement superficiel 100 de matière dure peut par exemple être réalisé par fusion au chalumeau ou à l'arc électrique d'un cordon de soudure, selon les procédés classiques de rechargement par soudure.The method is compatible with a subsequent step during which a surface coating 100 of hard material can be produced on the leading face 6 and the front facet 8, as shown in FIGS. 11 to 16. The surface coating 100 of material hard can for example be made by welding with a torch or an electric arc of a weld bead, according to conventional methods of reloading by welding.

Pour améliorer la cohésion entre la structure métallique de corps de dent et les parties en matériau dur, on peut recourir, avant infiltration-soudure, à une étape préalable de préparation de la surface de l'ébauche devant être au contact de la matière dure. La préparation peut comprendre les phases suivantes :

  • meulage ou grenaillage de la surface,
  • métallisation d'un voile d'alliage de type nickel/chrome/bore/silicium autofusible, à l'aide d'un chalumeau.
To improve the cohesion between the metal structure of the tooth body and the parts made of hard material, recourse may be had, before infiltration-welding, to a prior step of preparing the surface of the blank to be in contact with the hard material. Preparation can include the following phases:
  • surface grinding or shot blasting,
  • metallization of an alloy veil of nickel / chromium / boron / autofusible silicon type, using a torch.

La présente invention n'est pas limitée aux modes de réalisation qui ont été explicitement décrits, mais elle en inclut les diverses variantes et généralisations contenues dans le domaine des revendications ci-après. On peut notamment, sans sortir du cadre de l'invention, prévoir un nombre de barreaux de matériau dur différent de cinq, des sections de barreaux différentes de la section rectangulaire, des formes non planes de face d'attaque et de face de fuite de dent.The present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof contained in the field of claims below. It is possible in particular, without departing from the scope of the invention, to provide a number of bars of hard material other than five, sections of bars different from the rectangular section, non-planar shapes of leading face and trailing face of tooth.

Claims (15)

  1. Tooth for excavating tool such as a dredger or revolving cutter head excavator for use in mines consisting of a tooth body structure made of a mechanically resistant metal or alloy having a fixing area (10) to join it to a drive structure (1) and a working area (11) to dig the soil, the working area (11) generally being flat, shaped like a shovel and limited by a leading face (6) and a trailing face (7) which are generally flat or slightly curved and connected by a front tapered facet (8) that defines a transverse cutting edge (9), the working area (11) consisting of a row of bars (24, 33, 34, 35, 36) consisting of a mixture based on particles of hard material bonded in a matrix, the said bars being longitudinal and essentially perpendicular to transverse cutting edge (9) and forming a row of bars inserted in the interstices of a metal comb with several spars (25, 26, 29, 30, 31, 32) made up by the rest of the body structure characterised in that, in those parts of the cross section that include longitudinal bars made of particles of hard material (24, 33, 34, 35, 36), the material with particles of hard material takes up the entire height of the tooth between the leading face (6) and the trailing face (7).
  2. Tooth according to claim 1 characterised in that the longitudinal bars made of hard material (24, 33, 34, 35, 36) are separated from the front facet (8) by a metal crosspiece (28).
  3. Tooth according to claim 2 characterised in that the longitudinal bars made of hard material (24, 33, 34, 35, 36) are linked to each other by bridges of hard material (38, 39, 40, 41) of which the height is less than that of the bars and with which they form a plate of hard material (47) which constitutes the central part of leading face (6).
  4. Tooth according to claim 3 characterised in that the front ends of the bars of hard material (24, 33, 34, 35, 36) are joined to each other by a crosspiece made of hard material (37) of which the height essentially equals the height of the bars.
  5. Tooth according to any of claims 1 to 4 characterised in that the bars made of hard material (24, 33, 34, 35, 36) are roughly 4 to 15 mm thick and are separated by metal areas (25, 26, 29, 30) which are roughly 4 to 15 mm thick.
  6. Tooth according to any of claims 1 to 5 characterised in that the bars made of hard material (24, 33, 34, 35, 36) are essentially as long as the length of the maximum permissible area of wear of the tooth.
  7. Tooth according to any of claims 1 to 6 characterised in that the leading face (6), front facet (8) and the lateral edges (12, 13) are covered in a layer (100) of material based on particles of hard material bonded in a matrix.
  8. Tooth according to any of claims 1 to 7 characterised in that the longitudinal bars made of hard material (24, 33, 34, 35, 36) contain particles of molten tungsten carbide.
  9. Tooth according to claim 8 characterised in that some of the particles of molten tungsten carbide have a diameter equal to or greater than 2 mm.
  10. Tooth according to any of claims 1 to 9 characterised in that the bars made of hard material (24, 33, 34, 35, 36) are bonded to the metal of the tooth body by a brazing alloy forming the said matrix that links the particles of hard material.
  11. Process to produce a tooth according to claims I to 10 for an excavating tool such as a dredger or revolving cutter head excavator for use in a mine of the type consisting of a tooth body structure made of metal or alloy which is mechanically resistant having a fixing area (10) to join it to a drive structure (1) and a working area (11) to dig the soil, the working area generally being flat and shovel shaped and limited by a leading face (6) and a trailing face (7) which are generally flat or slightly curved and connected by a tapered front facet (8) defining a transverse cutting edge (9), the working area consisting of bars (24, 33, 34, 35, 36) consisting of a mixture based on particles of hard material bonded in a matrix, the said bars being embedded in the metal of the tooth body and forming longitudinal bars that are essentially perpendicular to transverse cutting edge (9), this process being characterised in that it comprises the following steps:
    a) Produce a blank (42) made of metal or alloy consisting of the fixing area (10) and the working area metal part (11), the said working area metal part consisting of a series of longitudinal slots (43) opening out into leading face (6) and trailing face (7) and separated by spars (25, 26, 29, 30, 31, 32);
    b) Place the said blank (42) on a mounting (44) with its leading face (6) upwards and in an essentially horizontal direction;
    c) Fill the said longitudinal slots (43) with particles of a hard anti-abrasion material (45) such as molten tungsten carbide or the like, vibrate this assembly so that the particles are in as close as possible contact with the walls of the slots and are contiguous with each other;
    d) Prepare a sufficient quantity of an appropriate alloy (46) in a form suitable to ensure subsequent distribution of the alloy during a subsequent melting phase, the alloy being a brazing alloy capable of wetting the particles of hard material (45) and the material which forms the blank (42) and of melting at a temperature less than the melting point of the blank (42) and the mounting (44);
    e) Heat this assembly to a temperature higher than the melting point of the alloy (46) and lower than the melting point of the blank (42) and the mounting (44) in order to ensure infiltration of the molten alloy between the particles of hard material (45);
    f) Allow to cool and separate the piece thus obtained from its mounting.
  12. Process according to claim 11 characterised in that it includes an initial operation to prepare the surface of the blank which is in contact with the hard material, this preparation stage consisting of the following phases:
    - Grinding or shot blasting of the surface,
    - Plating of a thin film of alloy of the self-fusing nickel-chrome-boron-silicon type by means of a welding torch.
  13. Process according to any of claims 11 or 12 characterised in that:
    - The blank (42) is such that the intermediate metal spars (25, 26, 29, 30) are offset from leading face (6) defined by the outer spars (31, 32),
    - During the filling and infiltration stage, the hard material (45) fills the slots (43) and covers the intermediate spars to make a plate of infiltrated hard material (47) forming the central area of leading face (6).
  14. Process according to claim 13 characterised in that:
    - The front ends of the outer spars (31, 32) are linked to each other by a metal crosspiece (28) whereas the intermediate spars (25, 26, 29, 30) have a free end that is separated from the metal crosspiece (28) by a gap,
    - During the filling and infiltration phase, the hard material (45) fills the said gap separating the free ends of the intermediate spars and the metal crosspiece (28) to form a crosspiece of hard material (37).
  15. Process according to any of claims 11 or 12 characterised in that it includes a subsequent stage to produce a surface coating (100) of hard material that covers, in particular, leading face (6) and front facet (8) by fusing a welding bead.
EP91917196A 1990-09-20 1991-09-18 Excavating tool tooth Expired - Lifetime EP0548239B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT9191917196T ATE105355T1 (en) 1990-09-20 1991-09-18 BUCKET TOOTH.

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR909011828A FR2667088B1 (en) 1990-09-20 1990-09-20 TOOTH FOR EXCAVATION TOOL.
FR9011828 1990-09-20
PCT/FR1991/000735 WO1992005320A1 (en) 1990-09-20 1991-09-18 Excavating tool tooth

Publications (2)

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EP0548239A1 EP0548239A1 (en) 1993-06-30
EP0548239B1 true EP0548239B1 (en) 1994-05-04

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US (1) US5375350A (en)
EP (1) EP0548239B1 (en)
AU (1) AU648826B2 (en)
CA (1) CA2091888A1 (en)
DE (1) DE69101927T2 (en)
ES (1) ES2055617T3 (en)
FR (1) FR2667088B1 (en)
WO (1) WO1992005320A1 (en)

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WO2020144028A1 (en) * 2019-01-11 2020-07-16 Thyssenkrupp Industrial Solutions Ag Tooth for attaching to an excavator bucket
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FR2667088A1 (en) 1992-03-27
FR2667088B1 (en) 1994-10-14
CA2091888A1 (en) 1992-03-21
ES2055617T3 (en) 1994-08-16
EP0548239A1 (en) 1993-06-30
AU8545191A (en) 1992-04-15
DE69101927D1 (en) 1994-06-09
AU648826B2 (en) 1994-05-05
DE69101927T2 (en) 1994-11-24
US5375350A (en) 1994-12-27
WO1992005320A1 (en) 1992-04-02

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