EP0143289A1 - Frog for switches or crossings, and method of manufacturing them - Google Patents

Abstract

In a frog for switches or crossings, essentially consisting of conventional, weldable rail steel, having two wing rails (1) and a frog tip (4) arranged between the wing rails (1) and extending from a starting region (2) to an end region (3), in which frog the frog tip (4) forms with the wing rails (1) two routing and guide channels (5) which run at an acute angle relative to each other, it being possible for connecting rails (6) to be welded on the one hand onto free ends of the wing rails (1) and on the other hand onto the end region (3) of the frog tip (4) and the region of greatest wear being equipped with austenitic manganese steel, an optimum construction in terms of manufacture and application is achieved if the wing rails (1) and the frog tip (4) together are designed as a one-part frog block (7) consisting of conventional, weldable rail steel, if the frog block (7) in the region of greatest wear, thus especially in the starting region (2) of the frog tip (4), has a recess (8), and if a frog insert (9) of austenitic manganese steel is firmly inserted in the recess (8). In a frog of this type, the frog insert (9) can be readily held with a press fit in the recess (8), it being particularly advantageous for a low temperature shrinkage method to be used for producing this press fit. <IMAGE>

Description

The invention relates to a centerpiece for switches or crossings, consisting essentially of conventional, weldable rail steel, with two wing rails and a centerpiece tip arranged between the wing rails and widening from an initial region to an end region, the centerpiece tip with the wing rails being two acute angles to one another - And guide grooves forms, connecting rails can be welded on the one hand to free ends of the wing rails, and on the other hand to the end region of the frog tip, and in the area of greatest wear, in particular in the beginning region of the frog tip, equipment with high manganese steel is provided. The invention also relates to a method for producing such a centerpiece.

The known centerpiece, from which the invention is based (cf. DE-AS 20 42 488), consists of three parts, namely two wing rails and the centerpiece tip. These three parts are welded together into a manageable core. This core is made of common, weldable rail steel. Taking into account the special stress of such a frog in the wear area, this frog is provided with armor made of a manganese steel alloy in the wear area, namely in the beginning area of the frog tip and on the overflow edges of the adjacent wing rails. This armor made of a manganese steel alloy is applied to the centerpiece tip and the corresponding areas of the wing rails by means of electron beam welding. This complex construction is necessary because manganese hard steel cannot be easily welded to the usual rail steels, since temperatures above approx. 570 K lead to the manganese hard steel becoming brittle. Even with the process of electron beam welding, the desired armoring made of a manganese high-carbon steel alloy cannot be reliably connected to the rest of the rail steel of the heart. Despite the very considerable manufacturing effort that such a centerpiece requires, none is optimal for practice appropriate success achieved. In addition, armor made of manganese steel is naturally inferior to a solid part made of manganese steel.

Since manganese hard steel is extremely well suited as a particularly wear-resistant material for the wear area of frogs of the type in question, but with manganese hard steel the above-mentioned considerable problems arise in the manufacture of welded connections, screw connections are preferred in practice. In such a known centerpiece (cf. DE-OS 22 44 902), the centerpiece tip is designed as a part that is particularly susceptible to wear as a manganese-coated casting. The centerpiece tip is screwed to the wing rails via connecting straps. However, such screw connections are not without problems in practice, since they can come loose in continuous operation, i. H. require constant monitoring and are also relatively prone to repair.

Finally, a core piece for switches or crossings, which is produced entirely as a one-piece casting, is known (see DE-AS 12 42 252), which consists of a central area (wear area) made of high-manganese steel, front end areas made of a weldable rail steel and between the central area and the End regions formed, mixing zones produced by a composite casting process. It has been shown that this core is not optimal in operation and that the process for its production as a composite casting process is extremely complex.

Taking into account the prior art explained in detail above, the invention is based on the object of specifying a centerpiece of the type described at the outset, which combines the advantages of the known centerpieces explained above in terms of production technology and application technology, in which case welded connections with connecting rails can be produced without any problems and nevertheless an optimal wear-free design of the wear area is possible. The object of the invention is also to provide of a method for producing such a core.

The centerpiece according to the invention, in which the above-mentioned object is achieved, is initially characterized in that the wing rails and the centerpiece tip are formed with one another as a one-piece centerpiece block made of customary, weldable rail steel, that the centerpiece block is in the area of greatest wear, in particular in the beginning area of the Frog tip, has a recess and that a frog insert made of high manganese steel is firmly inserted into the recess. The production of such a frog block, which includes the wing rails and the frog tip, is easily possible with modern manufacturing methods. In this frog block, the frog insert made of manganese steel is embodied as a separate part. The centerpiece insert itself can also be easily manufactured as an independent part. The connection of the frog insert to the frog block can be realized permanently and robustly because of the shape of the embedding of the frog insert in a recess in the frog block.

The heart of the invention can be easily welded to connecting rails. Nevertheless, the wear area of the centerpiece can also be easily produced from the preferred manganese steel. All the advantages of the known frogs explained at the outset are combined in the frog according to the invention.

There are now various options for designing and developing the centerpiece according to the invention, which will only be explained below by way of example.

First of all, it is advisable to design the centerpiece insert of the centerpiece according to the invention in such a way that it encompasses both the start region of the centerpiece tip and the adjacent upper run regions of the wing rails. In the centerpiece insert there are of course between the centerpiece tip and the wing rails formed the driving and guide grooves explained above. In principle, it is also conceivable that in such a case the frog insert is made in several parts.

With regard to the choice of material for the centerpiece insert, it is advisable to produce it as a casting from 12 to 14% high manganese steel.

As far as the recess in the frog block for receiving the frog insert is concerned, there are of course various options.

A first possibility, which is quite practical in terms of production technology, is to design the recess as a tub which is only open at the top. The centerpiece insert is then inserted into the recess from above and held in this recess in some way. How this can be done in detail will be explained in more detail later.

A second possibility is characterized in that the recess in the frog block is open at the top and on one long side and that the frog insert can be inserted into the recess in the frog block from the open long side.

Finally, a third possibility is characterized in that the recess in the frog block is open at the top and on both long sides, that is to say represents a channel running transversely to the direction of extension of the frog.

While straight or upward diverging walls of the recess are required in the possibility explained above in the first place, for the second and third possibility an embodiment of the centerpiece according to the invention is recommended, which is characterized in that the recess has undercuts on the edge, in particular trapezoidal in cross section is formed, and that the frog insert the edge Has undercuts corresponding formations, in particular is correspondingly trapezoidal in cross section. In the second possibility with an opening open at the top and only on one long side, such undercuts can be provided on the three other sides, while in the third possibility with such an undercut open upwards and on both long sides, such undercuts can only be provided on the two remaining end faces can. In any case, these undercuts prevent the centerpiece insert from being removed upward from the recess.

While there is only a single possibility from the outset of how the centerpiece insert can be inserted into the recess in the previously explained second possibility, a clear insertion path can also be specified in the previously explained third possibility, namely by the sides of the crosswise to the direction of extension of the centerpiece Recess (or the centerpiece insert) are not arranged exactly parallel to each other.

Unless a sufficiently firm connection of the frog insert to the frog block can be provided in another way, it is advisable to provide, at least in addition, screw connections for connecting the frog insert to the frog block. This is particularly true, of course, if the recess in the frog block is open on one long side or on both long sides. Such screw connections are expediently arranged on the edge or on the edges of the frog insert.

In particular, with regard to the screw connections, an embodiment of the frog according to the invention is recommended, which is characterized in that the frog block is provided with threaded bores in the region of the recess and the frog insert is provided with push-through holes which are aligned with the threaded bores when the frog insert is inserted into the recess, and that fitting screws are provided through the push-through holes can be inserted and screwed into the threaded holes. To do the screw To bind the connections or the fitting screws of the screw connections in an area that is not problematic from an operational point of view, it is advisable to provide the centerpiece insert with a gradation in the area of the screw connections.

In particular when the recess in the frog block is designed as a trough which is only open at the top, the frog insert can be firmly connected to the frog block by being held in the press fit in the recess.

In order not to make the one-piece frog block provided according to the invention unnecessarily long and wide, a configuration of the frog according to the invention is recommended, which is characterized in that the wing rails are provided in the region of the connecting rails welded to the end region of the frog tip. The wheel control arms are expediently attached to wheel handlebar stands which are known per se and which do not need to be explained further here.

In order to make the upper run area of wing rails and frog tip particularly easy to drive, the frog insert should have a trapezoidal shape in plan view on both end faces. In this context, it is also advisable to design the centerpiece according to the invention in such a way that the centerpiece tip rises in a concave-arc shape in the initial region from the level of the bottom of the driving and guide grooves to a level slightly below the treads of the wing rails and then to the level of Treads of the wing rails is just rising. As a result, the load of an overflowing wheel is only fully transferred to the frog tip when its width is sufficiently large.

The subject matter of the invention, as has been explained at the beginning, is also a method for producing a heart of the type in question. The method according to the invention is characterized in that the heart Piece block from a cast, forged or rolled starting block by shaping the wing rails, the driving and guide grooves, the centerpiece tip, the end areas for welding the connecting rails and the recess for the centerpiece insert and the centerpiece insert with wing rails, driving and guide grooves and centerpiece tip made of manganese hard steel is finished pouring. These process steps take into account the fact that the necessary driving and guiding grooves, etc., can be produced with precision and inexpensively in the forged centerpiece block, for example, on modern machine tools, while a casting method made of wear-resistant manganese steel is more expedient for the centerpiece insert.

Finally, a special embodiment of a method according to the invention for the production of a frog is recommended, in which the frog insert is held in the recess in the frog block in a press fit, which is characterized in that the frog insert is manufactured with external dimensions that are normal operating temperatures to be expected are slightly larger than the dimensions of the recess in the frog block, that before inserting the frog insert into the recess in the frog block, the frog insert to a temperature that is very low compared to the normal temperature during operation and / or the frog block to a temperature that is high compared to the normal temperature during operation is brought and that the frog insert is then inserted into the recess in the frog block. In this way, in particular when the recess in the frog block is only open at the top, a connection of the frog insert to the frog block that is absolutely firm during operation can be realized without the need for screw connections.

• Fig. 1 ein erstes Ausführungsbeispiel eines erfindungsgemäßen Herzstückes für eine Weiche in schematischer Darstellung,
• Fig. 2 einen Schnitt durch den Gegenstand nach Fig. 1 entlang der Linie II-II,
• Fig. 3 einen Schnitt durch den Gegenstand nach Fig. 1 entlang der Linie III-III,
• Fig. 4 einen Schnitt durch den Gegenstand nach Fig. 1 entlang der Linie IV-IV,
• Fig. 5 ein zweites Ausführungsbeispiel eines erfindungsgemäßen Herzstückes für eine Weiche in schematischer Darstellung,
• Fig. 6 einen Schnitt durch den Gegenstand nach Fig. 1 entlang der Linie VI-VI,
• Fig. 7 einen Schnitt durch den Gegenstand nach Fig. 1 entlang der Linie VII-VII,
• Fig. 8 einen Schnitt durch den Gegenstand nach Fig. 1 entlang der Linie VIII-VIII,
• Fig. 9 ein drittes Ausführangsbeispiel eines erfindungsgemäßen Herzstückes für eine Weiche in schematischer Darstellung,
• Fig. 10 einen Schnitt durch den Gegenstand nach Fig. 1 entlang der Linie X-X,
• Fig. 11 einen Schnitt durch den Gegenstand nach Fig. 1 entlang der Linie XI-XI.und
• Fig. 12 einen Schnitt durch den Gegenstand nach Fig. 1 entlang der Linie XII-XII.

In the following, the invention is explained in more detail with reference to a drawing which only shows exemplary embodiments; it shows

• 1 shows a first exemplary embodiment of a centerpiece according to the invention for a switch in a schematic illustration,
• 2 shows a section through the object according to FIG. 1 along the line II-II,
• 3 shows a section through the object according to FIG. 1 along the line III-III,
• 4 shows a section through the object according to FIG. 1 along the line IV-IV,
• 5 shows a second exemplary embodiment of a centerpiece according to the invention for a switch in a schematic illustration,
• 6 shows a section through the object according to FIG. 1 along the line VI-VI,
• 7 shows a section through the object according to FIG. 1 along the line VII-VII,
• 8 shows a section through the object according to FIG. 1 along the line VIII-VIII,
• 9 shows a third exemplary embodiment of a centerpiece according to the invention for a switch in a schematic illustration,
• 10 shows a section through the object according to FIG. 1 along the line XX,
• Fig. 11 is a section through the article of Fig. 1 along the line XI-XI. And
• Fig. 12 is a section through the object of FIG. 1 along the line XII-XII.

The basic structure of the centerpiece according to the invention for switches or crossings will first be explained with reference to FIG. 1.

The centerpiece consists essentially of customary, weldable rail steel and has two wing rails 1 and a centerpiece tip 4 which is arranged between the wing rails 1 and widens from an initial region 2 to an end region 3. The centerpiece tip 4 forms with the wing rails 1 two driving and guide grooves 5 which run at an acute angle to one another. On the one hand to free ends of the wing rails 1, and on the other hand to the end region 3 of the centerpiece tip 4, connecting rails 6 are weldable or welded in the exemplary embodiment shown. In the area of the greatest wear, in particular in the initial area 2 of the frog tip 4, equipment with high manganese steel is provided, as will be explained below.

As can clearly be seen in FIG. 1, the wing rails 1 and the frog tip 4 are designed together as a one-piece frog block 7 made of conventional, weldable rail steel. The frog block 7 has a recess 8 in the area of greatest wear, into which a frog insert 9 made of high manganese steel is firmly inserted. This is particularly clear from FIG. 1 in conjunction with FIG. 2.

In the exemplary embodiment shown, the frog insert 9 comprises both the initial region 2 of the frog tip 4 and also adjacent overflow regions 10 of the wing rails 1.

In the embodiment shown in FIG. 1, the recess 8 in the frog block 7 is designed as a trough which is only open at the top. This is shown particularly clearly in FIG. 3. 3 shows the driving and guide grooves 5 particularly well.

While in the embodiment according to FIG. 1 the recess 8 is designed as a trough which is only open at the top, in the embodiment according to FIG. 5 the recess 8 in the frog block 7 is open at the top and on one long side, so that the frog insert 9 is from the open long side can be inserted into the recess 8 in the frog block 7.

In the exemplary embodiment according to FIG. 9, the recess 8 in the frog block 7 is open at the top and on both longitudinal sides, thus forming a channel running transversely to the direction of extension of the frog.

As shown in FIGS. 6, 7 and 10, the recess 8 in the second and third exemplary embodiment of a centerpiece according to the invention has undercuts 11, namely is trapezoidal in cross section. Here, the centerpiece insert 9 is provided on the edge side with the undercuts 11 corresponding formations 12, namely also correspondingly trapezoidal in cross section.

In the second and third exemplary embodiment of the centerpiece according to the invention, 7 screw connections 13 are provided for connecting the centerpiece insert 9 to the centerpiece block. This is indicated in FIGS. 5 and 9 and shown in more detail in FIGS. 7 and 11. 7 and 11 show that the frog block 7 is provided in the region of the recess 8 with threaded holes 14 and the frog insert 9 is provided with through holes 15 aligned with the threaded holes 14 when the frog insert 9 is inserted into the recess 8, and that fit screws 16 are provided by the Push-through bores 15 can be pushed through and screwed into the threaded bores 14. The centerpiece insert 9 has a gradation 17 or gradations 17 in the area of the screw connections 13 or in the areas of the screw connections 13, as can be seen from FIGS. 7 and 11.

In the first embodiment of a frog according to the invention shown in FIGS. 1 to 4, a special feature is that the frog insert 9 is held in the recess 8 in a press fit. This is achieved in that the frog insert 9 is produced with external dimensions that are slightly larger than the dimensions of the recess 8 in the frog block 7 at the temperatures that normally occur during operation, and that before the frog insert 9 is inserted into the recess 8, the frog insert 9 is brought to a temperature which is very low compared to the normal temperature during operation and is only then inserted into the recess 8 in the frog block 7. When warming up to the normal temperature during operation, the frog insert 9 expands somewhat and wedges absolutely firmly in the recess 8 in the frog block 7.

In accordance with all three exemplary embodiments of the frog according to the invention, it is provided that in the region of the connecting rails 6 welded to the end region 3 of the frog tip 4, the wing rails 1 extending wheel links 18 are arranged. The wheel control arms 18 are attached to conventional wheel control arms 19. 4, 8 and 12 show known fastenings 20 which engage on the rail foot so as to fasten the parts of the heart according to the invention to a rail support plate 21 or the like.

1 finally shows a particularly preferred embodiment of a frog according to the invention when the frog insert 9 has a trapezoidal shape in plan view on both end faces. This is particularly convenient.

2, 6 and 10, the shape of the centerpiece tip 4, which rises in a concave-arc shape from the level of the bottom of the driving and guide grooves 5 to a level slightly below the running surfaces of the wing rails 1, is also visible in FIGS. 2, 6 and 10 then only rises to the level of the tread of the wing rails 1.

Finally, a uniform block width for frog blocks 7 of frogs allows the use of uniform rib plates for these frog blocks 7. Furthermore, it is of course easily possible to design frog blocks 7 for use with curved switches in a corresponding curved shape. At intersections, double frogs can also be designed with uniform frog blocks 7 in the manner explained.

Claims (11)

1. Centerpiece for switches or crossings, essentially consisting of conventional, weldable rail steel, with two wing rails and a centerpiece tip arranged between the wing rails and widening from an initial region to an end region, the centerpiece tip with the wing rails two driving and running at an acute angle to one another Guide grooves form, connecting rails being weldable to free ends of the wing rails on the one hand, and to the end region of the frog tip, on the other hand, and in the area of greatest wear, in particular in the beginning region of the frog tip, being provided with high manganese steel, characterized in that the wing rails (1) and the frog tip (4) with one another as a one-piece frog block (7) made of common, weldable rail steel that the frog block (7) in the area of greatest wear, in particular in the beginning area (2) of the frog tip (4), e has a recess (8) and that in the recess (8) a core insert (9) made of high manganese steel is firmly inserted. 2. centerpiece according to claim 1, characterized in that the centerpiece insert (9) comprises both the initial region (2) of the centerpiece tip (4) and the adjacent overflow regions (10) of the wing rails (1). 3. centerpiece according to claim 1 or 2, characterized in that the centerpiece insert (9) is made as a casting from 12 to 14% high manganese steel. 4. frog according to one of claims 1 to 3, characterized in that the recess (8) in the frog block (7) is designed as a tub open only upwards or the recess (8) in the frog block (7) is open upwards and on one long side and the frog insert (9) can be inserted from the open long side into the recess (8) in the frog block (7) or the recess (8) in the frog block (7) is open and open on both long sides is, that is, a channel running transversely to the direction of extension of the frog. 5. centerpiece according to claim 4, characterized in that the recess (8) has undercuts on the edge (11), in particular is trapezoidal in cross-section, and the centerpiece insert (9) on the edge of the undercuts (11) has corresponding formations (12), in particular is correspondingly trapezoidal in cross section. 6. frog according to one of claims 1 to 5, characterized in that the frog block (7) in the region of the recess (8) with threaded bores (14) and the frog insert (9) with in the recess (8) inserted frog insert (9 ) to the threaded holes (14) aligned through holes (15) is provided and that fitting screws (16) can be inserted through the through holes (15) and screwed into the threaded holes (14). 7. centerpiece according to one of claims 1 to 6, characterized in that the centerpiece insert (9) in the recess (8) is held in a press fit. 8. centerpiece according to one of claims 1 to 7, characterized in that in the region of the end portion (3) of the frog tip (4) welded connecting rails (6), the wing rails (1) extending wheel links (18) are provided. 9. centerpiece according to one of claims 1 to 8, characterized in that the centerpiece tip (4) in the initial region (2) from the level of the bottom of the driving and guide grooves (5) to a level slightly below the running surfaces of the wing rails (1) rising concave-arc-shaped and then straight up to the level of the running surfaces of the wing rails (1). 10. A method for producing a frog according to one of claims 1 to 9, characterized in that the frog block from a cast, forged or rolled starting block by shaping the wing rails, the driving and guide grooves, the frog tip, the end regions for welding the connecting rails and the recess for the centerpiece insert is formed and the centerpiece insert with wing rails, driving and guide grooves and centerpiece tip is cast from high manganese steel. 11. A method for producing a frog according to claim 7, characterized in that the frog insert is made with external dimensions that are slightly larger than the dimensions of the recess in the frog block at normal temperatures to be expected during operation, that before inserting the frog insert into the recess in the frog block, the frog insert is brought to a temperature which is very low compared to the normal temperature during operation and / or the frog block is brought to a temperature which is high compared to the normal temperature during operation and that the frog insert is then inserted into the recess in the frog block.

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