EP1800988B1 - Buffer for railway vehicles and method for manufacture of the buffer - Google Patents

Abstract

The buffer for rail vehicles includes a buffer plate (6) of plastic which is housed and fixed in a buffer head (1), wherein the buffer plate has a basically smooth surface on the rear side which faces the base of a recess (3) in the buffer head, while the base of the recess has projections and/or indentations (5) which may be in groove form and recessed into the base in helical fashion. An independent claim is included for a method for producing a buffer for rail vehicles in which the base of the recess in the buffer head is provided with indentations and/or projections by means of a cutting process, by laser machining, forging, eroding, embossing or casting.

Description

The invention relates to a buffer for rail vehicles according to the preamble of claim 1 and a method for producing the buffer according to the preamble of claim 7.

In order to reduce the frictional forces between the buffers of rail vehicles during coasting or braking, buffers are increasingly used with an existing plastic impact surface. For this purpose, the buffer head is usually provided with a recess in which a plastic buffer plate is received and fixed.

From the CH 370 109 a buffer for rail vehicles is known, the buffer head is occupied to form a shock surface with an inner part made of plastic and an outer part made of steel. The outer part is provided with a conically widening in the direction of the buffer head bore. In this hole, the provided with a corresponding edge inner part is held. The outer part is attached to the buffer head with the help of rivets.

In the EP-A-1 354 778 a buffer for rail vehicles is described in which the buffer plate is provided with a recess in which a plastic buffer plate is received. In order to use the buffer plate in the recess, the buffer plate is elastically deformed by compressive load and then fixed along its circumference in the deformed position by means of a first sleeve. Subsequently, the first sleeve is placed and aligned on the recess of the buffer plate, so that the buffer plate can be pressed into the recess. Subsequently, the buffer plate relaxes by utilizing its material elasticity, so that it is then fixed in a form-fitting manner along the edge in the recess.

In the aforementioned embodiments, the respective recess in the buffer plate has a smooth bottom and the buffer plate is neither by mechanical Fixing means still fixed by gluing at the bottom of the recess. As a result, there is a risk that the buffer plate is damaged when exposed to lateral impact forces, such as those that can occur when passing through tight bends. When driving through tight curves, it may happen that the side edge of a buffer head acts on the buffer plate of the counter-buffer in such a way that the buffer plate begins to bulge and thereby kinked, sheared or completely pushed out of the recess. This is due primarily to the fact that the back of the respective buffer plate is fixed only by clamping in the recess and there is no positive or non-positive connection with the bottom of the recess.

To remedy this problem, it would be obvious to fix the buffer plate in the recess either by mechanical fastening means or by gluing. However, the attachment of mechanical fasteners such as screws is associated with disadvantages, as this would increase the manufacturing cost of the buffer and the impact surface of the buffer plate would also have to be provided with unwanted openings. On the other hand, the bonding of a polyamide buffer plate is connected to a steel buffer plate due to the different material properties and in particular the different expansion coefficients with difficulty.

Finally is from the GB 809 137 a railway buffer known, the buffer head is provided with a round opening, which widens conically towards the buffer head. In a first embodiment, the opening is embedded in a head part, which is fastened by means of rivets on the actual buffer head. The buffer plate is inserted in this case from behind into the head part and the head part is then fastened by means of the rivets on the buffer head. In another embodiment, the opening is recessed directly into the buffer head. In this case, a fastening tool is provided, by means of which the buffer plate is deflected so far that it can be inserted into the opening. After removal of the fastening tool, the buffer plate relaxes, whereby she fixes herself in the opening. In addition, it is mentioned that an adhesive bond can be provided for fastening the buffer plate in the recess. Alternatively, the buffer plate can also be poured into the recess, in which case the recess can be provided with projections or recesses to form a toothing with the cast-in buffer plate.

The invention aims to develop a buffer for rail vehicles such that a buffer plate made of plastic can be fixed in a recess of the buffer head, that the risk of damaging the buffer plate is largely eliminated even when exposed to lateral forces, the production cost of the buffer should not be increased significantly.

For this purpose, a buffer according to claim 1 is provided according to the invention. A method for producing the buffer is given in claim 7.

The basic idea of the invention is to provide the bottom of the recess with elevations and / or depressions, which produce a positive and non-positive connection with the substantially smooth back of the buffer plate in the load case. Since the existing of a plastic such as polyamide buffer plate compared to the usual steel buffer head is comparatively soft and resilient, the buffer plate is under the action of impact forces, even if they have a large lateral component, against said elevations and / or pressed into the wells. In this case, the surface of the buffer plate conforms to the structure of the elevations and / or depressions, so that a positive and non-positive connection between the bottom of the buffer head and the buffer plate is effected, which ensures that the buffer plate is not laterally under the action of lateral forces can shift appreciably and does not begin to bulge appreciably and thus ultimately will not be damaged.

Advantageous developments of the buffer are defined in the dependent claims 2 to 6.

In claim 7, a method for producing a buffer head is also specified, in which the recess is provided with a surface enlarging structure. Preferred developments of the method are specified in the dependent claims 8 to 10.

• Fig. 1 einen nach dem Stand der Technik ausgebildeten Pufferkopf im Querschnitt,
• Fig. 2 einen erfindungsgemäss gestalteten Pufferkopf im Querschnitt,
• Fig. 3 den Pufferkopf gemäss Fig. 2 mit eingesetzter Pufferplatte, und
• Fig. 4 eine Draufsicht auf den Pufferkopf gemäss Fig. 2.

An embodiment of the invention will be explained in more detail with reference to a drawing. In this drawing shows:

• Fig. 1 a formed according to the prior art buffer head in cross section,
• Fig. 2 a buffer head designed according to the invention in cross-section,
• Fig. 3 the buffer head according Fig. 2 with inserted buffer plate, and
• Fig. 4 a plan view of the buffer head according to Fig. 2 ,

The FIG. 1 shows a formed according to the prior art buffer head in cross section. The buffer head forms part of a buffer for rail vehicles, as for example from the EP-A-1 083 105 is known. Since the basic structure of such buffers is known, essentially only addresses the essential features of the invention in connection with the buffer.

The buffer head 10, also called buffer plate, consists essentially of a plate 11 which is provided on the side facing away from the rail vehicle with a recess 12 for receiving a buffer plate made of plastic. The recess 12 is, seen in cross-section, designed substantially dovetail-shaped. In this recess 12 which can not be seen from this illustration, the buffer plate can be fixed by clamping. Although himself Buffer or buffer heads 10 have proven very useful in practice with such buffer plates, it may happen in individual cases that the buffer plate is so heavily loaded by the counter buffer, namely by the edge of the buffer head of the counter buffer when driving through a curve, ie in the transverse direction in that the buffer plate begins to bulge and thereby kinked, sheared or pushed out of the recess. This is due primarily to the fact that the back of the buffer plate is not positively or non-positively connected to the bottom 13 of the recess 12. Such a load occurs in particular in tight curves when the edge of a buffer head acts on the buffer plate of the counter-buffer, since in this case said buffer plate is loaded not only in the axial direction, but in particular also laterally. Therefore, the biggest risk of damaging the buffer plate is caused by the acting lateral forces.

Fig. 2 shows a inventively designed buffer head 1 in longitudinal section. As can be seen from this illustration, the bottom 4 of the recessed into the buffer head 1 and the base plate 2 recess 3 is provided with a plurality of groove-shaped recess 5.

The Fig. 3 shows the buffer head 1 according Fig. 2 with inserted into the recess 3 buffer plate 6. The buffer plate 6 may for example be made of polyamide and is preferably according to the in the EP-A-1 354 778 described method used in the recess. The groove-shaped recesses 5 are to ensure that in the case of loading a positive and non-positive connection between the back 7 of the buffer plate 6 and the bottom 4 of the recess 3 (FIGS. Fig. 2 ) is produced by the buffer plate 6 is pressed by the counter-buffer against these groove-shaped recesses 5 and against the groove-shaped recesses 5 bounding elevations, whereby the buffer plate 6 by their material elastic resilience quasi engages in these grooves, so that they are not laterally displaced can be. Thus, the previously described danger of bulging and a concomitant kinking, shearing, or squeezing the buffer plate 6 is eliminated.

Finally shows Fig. 4 a plan view of the buffer head 1 according Fig. 2 , On the one hand, it can be seen from this illustration that the recess 3 is round. In addition, the recessed in the bottom 4 of the recess 3 groove-shaped recesses 5 are shown in a schematic representation, in which case only a spiral groove is shown with exaggerated size shown slope. As can be seen, the buffer head 1 has a greater width than height. A horizontally extending in the transverse direction through the center of the base plate 2 is designated H.

Preferably, both the spherical front side of the buffer head 1 and the recess 3 and the recess (s) 5 are produced by machining on a lathe. For the production of the buffer head 1, usually a rectangular base plate 2 is used, which is provided on the lathe with a spherical front side. Thereafter, the recess 3 is produced by boring by means of a suitable machining tool. Finally, the bottom 4 of the recess 3 is provided with said groove structure, which also takes place by machining. Preferably, the groove is attached in the form of a spiral. For this purpose, the lathe machining tool centers in the center 4 of the recess 3 in the bottom 4 and is then moved radially outwards, while the buffer head 1 rotates in relation to the machining tool. Of course, the groove can also be made in reverse by moving the machining tool from the outside inwards. The groove produced in this way preferably has a depth between 1 and 2 mm and a pitch of 1 to 3 mm. The attachment of a spiral-shaped recess 5 on the bottom 4 of the recess 3 is quick, easy and inexpensive to accomplish, especially since the shape of the buffer head 1 already takes place on a lathe. It is understood that, of course, other shapes of elevations and / or depressions 5 can be provided instead of a spiral-shaped depression 5. It is only important that the elevations and / or depressions 5 do not run parallel to the horizontal H, but at least partially oblique, curved or transversely thereto, so that the buffer plate 6 in the action of Side forces not appreciably in the lateral direction, ie parallel to the horizontal H, can move.

On the other hand, the bottom 4 of the recess 3 can also be provided by laser processing, forging, erosion or by embossing with recesses 5, which form a surface enlarging structure. Of course, the basic shape of the buffer head 1 can also be produced in other ways, for example by forging, casting or by bending. Instead of depressions 5 surveys could be provided, for example, which are generated for example during casting. By casting surveys, of course, recesses automatically form again between the surveys.

Of course, instead of a round recess 3, deviating shapes such as, for example, rectangular or oval recesses 3 are also conceivable. Although the attachment of a spiral groove is very easy and inexpensive to accomplish, of course, other structures come into question, which form 4 elevations and / or depressions 5 in the surface of the bottom. It is important in particular that the said structure ensures the positive and non-positive connection between the bottom 4 of the recess 3 and the buffer plate 6, in particular under the action of lateral forces. This is, as already mentioned, achieved by the fact that the elevations and / or recesses 5 do not run parallel to the horizontal H and the buffer plate 6 compared to the buffer head 1 is comparatively soft, so that when pressure load of the buffer a form- and frictional connection between the back 7 of the buffer plate 6 and provided with elevations and / or depressions 5 bottom 4 of the recess 3 in the buffer head 1 is effected.

In any case, such a structure has the advantage that no additional connection, for example in the form of screws or an adhesive bond between the buffer plate 6 and the buffer head 1 must be provided.

Claims (10)

1. Buffer for rail vehicles, having a buffer head (1) which is provided with a recess (3) and in which a buffer plate (6), which is composed of plastic, is held and fixed, characterized in that the buffer plate (6) has an essentially smooth surface on the rear face (7) facing the bottom (4) of the recess (3), while the bottom (4) of the recess (3) is provided with projections and/or depressions (5).
2. Buffer according to Claim 1, characterized in that one or more groove-like depression or depressions (5) is or are incorporated in the bottom (4) of the recess (3).
3. Buffer according to Claim 1 or 2, characterized in that the groove-like depression or depressions (2) is or are incorporated in a spiral shape in the bottom (4) of the recess (3).
4. Buffer according to one of the preceding claims, characterized in that both the recess (3) which is incorporated in the buffer head (1) and the buffer plate (6) are round.
5. Buffer according to Claim 4, characterized in that a depression (5) which runs in a spiral shape is incorporated in the bottom (4) of the recess (3) and runs in a spiral shape outwards, from the centre (8) of the recess (3), or inwards from the outside.
6. Buffer according to one of the preceding claims, characterized in that the recess (3) has an essentially dovetail-shaped cross section and the buffer plate (6) is designed in a corresponding manner such that it is held in a clamped manner in the recess (3).
7. Method for production of a buffer for rail vehicles, having a buffer head (1) which is provided with a recess (3) and is designed to hold a buffer plate (6) which is composed of plastic, with the buffer plate (6) having an essentially smooth surface on the rear face (7) facing the bottom (4) of the recess (3), characterized in that the bottom (4) of the recess (3) is provided with depressions (5) and/or projections by means of metal-cutting machining, by laser processing, by forging, by erosion, by stamping or by casting.
8. Method according to Claim 7, characterized in that the buffer head (1) is provided with the recess (3) by metal-cutting machining on a lathe, and in that the structure is incorporated in the bottom (4) of the recess (3) after this.
9. Method according to Claim 7 or 8, characterized in that the buffer head (1) is fixed on a lathe, and the structure is incorporated in the bottom (4) of the recess (3), in the form of one or more depression or depressions (5).
10. Method according to Claim 9, characterized in that the respective depression (5) is incorporated in the bottom (4) of the recess (3) by moving a machining tool radially outwards from the centre (8) of the recess (3).

Images