Towing arrangement and deformation tube in a railway vehicle coupling

A towing arrangement intended for train couplers includes a bar (8), which at a rear end has an axially projecting pin (10), which projects through a through hole (40) in a plate (11), which on both sides is surrounded by shock-absorbing spring members (12), which always aim to hold the pin in a starting position in relation to the plate, and against the action of which the pin together with the bar are axially movable. The plate (11) is included in a mandrel (16) equipped with a cone (19), which mandrel is inserted into a deformation tube (17), more precisely into a wide, front tube section (22), which via a waist (23) transforms into a thinner, rear tube section (21), which is deformable by the mandrel (16). A deformation tube is also described.

TECHNICAL FIELD OF THE INVENTION

In a first aspect, this invention relates to a towing arrangement being intended for train couplers and of the type that comprises a bar, which at a rear end includes an axially projecting pin, which projects through a through hole in a plate, which on both sides is surrounded by shock-absorbing spring members, which always aim to hold the pin in a starting position in relation to the plate, and against the action of which the pin together with the bar are axially movable.

BACKGROUND OF THE INVENTION

Although arrangements of the above-mentioned type in practice have the purpose of, between different wheel-supported units, such as cars and/or locomotives, in a train unit transferring not only tractive forces but also thrust forces, the same are commonly denominated “towing arrangements” by those skilled in the art. Characteristic of such towing arrangements is that the same include a bar or registration arm (usually in the form of a tube), which at a rear end in one way or the other is fixed in one of the ends of a frame included in the vehicle unit in question, and which at a front end is connected to one or more additional details while forming a coupler. For instance, the front end of the bar may be directly connected to a coupler head and together with the same form an automatic coupler, but it may also via a muff coupling or the like be connected to a collision protection, which in turn is connected to a coupler head. In the towing arrangement, means are also included in order to absorb shocks of moderate character, i.e., such shock motions that every day arise and are transferred between the vehicle units during travel as well as in connection with coupling of the vehicle units.

DESCRIPTION OF PRIOR ART

In the market, a plurality of different types of towing arrangements are found, the kind initially mentioned of which makes use of spring members as shock-absorbing means. More precisely, one or more spring members are arranged on both sides of a plate having a through hole, in which a pin is inserted that protrudes axially from the rear end of the bar or registration arm of the towing arrangement. These spring members, which for instance may be composed of cushions or bodies of an elastic material, always aim to hold the pin, and thereby the bar, in a given starting position as long as the arrangement is not influenced by any appreciable shock motions, but as soon as shocks arise and manifest themselves in tractive motions in one direction and thrust motions in the opposite direction, these motions are absorbed by the spring members on both sides of the plate. A coupler assembled of just one such towing arrangement and a coupler head can of course absorb mild shocks and vibrations, but not such extreme shock forces that may arise in connection with collisions. Recently, demands have more and more often been raised that the couplers should be provided with particular collision protections, i.e., means, which in contrast to ordinary shock absorbers, have the capability of extincting extreme amounts of kinetic energy with the purpose of reducing and abating to the greatest possible extent the resulting effects in connection with strong collisions. If the couplers should be equipped with such collision protections, previously it has been necessary to place the means serving as collision protection in extension of the proper towing arrangement. In practice, a deformation tube is usually inserted between the towing arrangement and a coupler head. An aggravating disadvantage of this solution is, however, that the collision protection is based on the length, i.e., requires that the coupler in its entirety is given a great length. Furthermore, the solution is manufacturing-wise cost-demanding and results in difficulties with the construction in other respects.

OBJECTS AND FEATURES OF THE INVENTION

The present invention aims at obviating the above-mentioned problems and at providing an improved towing arrangement for train couplers. Therefore, a primary object of the invention is—in a first aspect—to provide a towing arrangement, in which a collision protection function is integrated in the proper towing arrangement. In other words, a coupler, which makes use of the towing arrangement according to the invention, should be able to assimilate and extinguish such extreme amounts of energy that arise upon collisions, without particular collision protection means needing to be inserted between, for instance, a coupler head and the towing arrangement. An additional object is to provide a towing arrangement that is structurally simple and thereby inexpensive to manufacture. Yet an object of the invention is to provide a towing arrangement, which after the occurrence of an accident has good chances to be restorable at a moderate cost.

FURTHER ELUCIDATION OF PRIOR ART

A collision protection in the form of a tube, which is deformable by means of a mandrel equipped with a cone, is previously known per se by EP 1 312 527. However, in this case, the collision protection is built-in in a link coupling, which lacks any shock-absorbing spring member of the type that characterizes the towing arrangement according to the present invention.

InFIG. 1,1generally designates a frame of the type that is included in any vehicle unit (e.g., a car, a locomotive or the like), and which together with other vehicle units may form a train unit. By those skilled in the art, the frame is at times also denominated body or chassis. At one end2of the frame, a towing arrangement in its entirety designated3is mounted, as well as two dead blocks4, only one of which is shown inFIG. 1. In the shown frame, two plates or panels5,6are included, between which a hollow space7is defined. In this hollow space, a rear part of the towing arrangement3is accommodated, while a front part of the same protrudes a distance from the end2of the frame. In this connection, it should be made clear that the concepts “front” and “rear”, respectively, relate to the proper towing arrangement and not to the frame. In other words, for the chosen terminology, it is insignificant whether the end2of the car is turned forward or rearward in the train unit.

A substantial part of the towing arrangement3consists of a bar or registration arm8, which in practice consists of a cylindrical tube. In the example, adjacent to the front end of the bar8, a muff coupling9is shown having the purpose of interconnecting the bar and another component, e.g., a coupler head, for the formation of an automatic coupler. From the rear end of the bar8(seeFIGS. 3 and 4), a pin10protrudes, which is thinner than the bar8and concentric with the geometrical centre axis C of the bar. The pin10projects through a hole40in a plate designated11. On both sides of this plate, shock absorbers or shock-absorbing spring members12are arranged, which advantageously may consist of cushions or bodies of an elastically deformable material, but which also could consist of mechanical compression springs, e.g., cup springs or screw springs. More precisely, one such spring member12is placed on the back side of the plate11, while two spring members12are present on the front side and are mutually spaced-apart by a washer13. Against the rear spring member12, a disc14is pressed. By means of a retaining element15, e.g., nut, the disc14is kept pressed against the spring member12by a predetermined pressure, which yields the desired degree of compression in the spring members12.

As far as the shown towing arrangement has been described hitherto, the same is in all essentials previously known. However, in previously known towing arrangements of this type, the plate11has served as a fastener, which has been fixed directly in the frame of the car or the vehicle unit. In doing so, the towing arrangement has in a satisfying way met not only the purpose of, between connected cars, transferring tractive as well as thrust forces, but also the purpose of absorbing and abating such moderate shock motions that permanently occur during, for instance, travel. However, the towing arrangement has not had any capability of extinguishing such amounts of kinetic energy that arise in connection with possible collisions.

Characteristic of the present invention is that the above-mentioned plate11is included in a mandrel in its entirety designated16, which is inserted into a deformable tube17, below denominated deformation tube. The mandrel16includes, in addition to the plate11, a cylinder18extending rearward from the same, which cylinder at the rear end thereof has a cone designated19. In the shown, preferred embodiment, the plate11and the cylinder18are made integrally from a first material, e.g., cast iron. The component made in this way has a shape similar to a barrel. The cone19consists in turn of a ring that is of a second material and formed with a conical surface20, which second material has greater compression strength than the material in the barrel-like component11,18. Advantageously, the ring19may be manufactured from hardened steel, the ring permanently being united to the cylinder18, e.g., by welding. The cone angle of the conical surface20may advantageously amount to about 40° (2×20°).

The deformation tube17, which is shown separately inFIG. 6, and which is of a cylindrical basic shape, includes a rear section21, which is spaced apart from a wider, front section22via a waist23, which tapers conically from the wide section22toward the thin section21. It is axiomatic that the inner diameter of the section22is larger than the inner diameter of the section21. More precisely, the inner diameter of the section22may correspond with—or be very little larger than—the outer diameter of the mandrel16, as this is determined primarily by the largest diameter of the cone19. The inner diameter of the section21is, however, considerably smaller than the outer diameter of the cone19. The interior, conical surface, which defines the waist23, is designated24. The cone angle of this surface may advantageously correspond with the cone angle (40°) of the conical surface20of the ring19. However, minor angle differences are feasible.

At the front end thereof, the deformation tube17has a comparatively robust flange25, which in the example has been made as a separate component, having a pipe socket25′, which has been united to the rest of the deformation tube via a welded joint26. The flange25has a rectangular contour shape and corbels out from the tube section22, while the inner diameter of the flange and the pipe socket substantially corresponds with the inner diameter of the tube section22. However, adjacent to the ring-shaped end surface27of the flange, a ring-shaped groove is recessed, which is defined by a planar, ring-shaped surface29as well as a cylindrical limiting surface. In the shown, preferred embodiment example, a female thread31is applied in said cylinder surface, which thread may be formed directly in the flange material or alternatively be made in a particular insert ring, which in turn is fixed against the cylinder surface. The width or axial extension of the proper thread31is somewhat smaller than the width or depth of the groove.

Said groove has the purpose of receiving a clamp ring32having an external male thread33.

As is best seen inFIG. 4, a circumferential groove is also formed adjacent to the front side34of the plate11, which groove is defined by a ring-shaped, planar shoulder surface36as well as a cylindrical surface37. The width of this cylinder surface may advantageously correspond with the width of the ring32(as this is counted between planar, opposite end surfaces of the ring), but be somewhat smaller than the depth of the groove that is defined in the flange25.

InFIG. 5(the cut A-A inFIG. 3), it is seen that the pin10has an out of round cross-section shape. More precisely, the shape is defined by two planar, parallel surfaces38, and two curved surfaces39. The hole40in the plate11, through which the pin10is brought, has a substantially square cross-section shape, and is considerably thicker than the pin10. As is seen inFIGS. 3 and 4, two insert bodies41of an elastically deformable or resilient material, e.g., rubber, are inserted into the hole40from opposite directions. In each such insert body41, a through hole is formed having the same out of round cross-section shape as the pin10. At least the planar, external surfaces38of the pin10have fine fit against the corresponding planar inner limiting surfaces in the insert bodies41. The deformable insert bodies41guarantee that the pin10normally assumes the rotation angle position that is shown inFIG. 5. However, upon the rather frequent occasions when the bar8, and thereby the pin10, is subjected to torsion stresses, the insert bodies permit a certain turning of the pin, although always against the action of the spring force in the material. In other words, the insert bodies form a torsion suspension, which, on one hand, guarantees requisite flexibility in the coupling between two cars, but which on the other hand always brings back the bar (and a coupler head belonging thereto) to a desired starting or normal position.

The Function and Advantages of the Towing Arrangement According to the Invention

First, reference is made toFIG. 1, in which the reference designation42implies how a vertical wall or panel is fixed in the hollow space7of the frame, more precisely at a distance inside the end2of the frame. In this panel42, there is a through, circular opening, the diameter of which is at least somewhat larger than the outer diameter of the coarse section22of the deformation tube. Thus, the deformation tube can be inserted through the opening until the flange25is pressed against the panel42. After this, the flange is fixed against the panel by means of suitable fastening elements, e.g., bolts, which are applied in co-operating holes43in the flange and the panel, respectively.

When the towing arrangement assumes the starting or normal state thereof (seeFIGS. 1-3), the cone19of the mandrel16is kept pressed, free of play, against the waist23of the deformation tube17. This takes place by means of the clamp ring32, which via the threaded joint31,33holds the mandrel in a position in which the cone surfaces20,24are pressed against each other by a certain pressure. Clamping of the mandrel may, per se, take place by means of the threaded clamp ring32only. However, in practice, it is preferred to press in the mandrel by means of a strong, hydraulic clamping mechanism (not shown), and then the clamp ring is tightened while forming a stop, which makes axial displacement of the mandrel in the forward direction impossible. In other words, the clamp ring holds the mandrel in place inside the wide section22of the deformation tube. On the contrary, the clamp ring32does not prevent the mandrel from moving axially rearward. Such a move of the mandrel is, however, prevented in the normal state according toFIG. 3by the waist23.

In any normal case, e.g., in connection with travel and coupling occasions, respectively, the motion-damping means of the towing arrangement in the form of the spring members12and the insert bodies41, respectively, work in a conventional way, i.e., tractive, thrust and rotary motions in the coupling between two cars are absorbed in a smooth and careful way.

However, if a collision would occur, in particular a collision during travel at high speed, the collision protection, which together is formed by the mandrel16and the deformation tube17, is activated. In the towing arrangement, an interaction of forces of high kinetic energy is then generated, the bar8together with the mandrel16being applied an aim to penetrate into the deformation tube. Such penetration may take place without hindrance by the clamp ring32, in that the smooth cylinder surface37of the mandrel freely can get loose from the likewise smooth inside of the clamp ring. When the mandrel16has left the clamp ring and started to move rearward, as is shown inFIG. 4, the tube17is successively deformed during conversion of the kinetic energy into heat energy. In such a way, the kinetic energy is extinguished under quick reduction of the resulting effects of the collision of the cars in the train unit as well as possible passengers therein. In this connection, it should be pointed out that the rear end flange44of the bar8(seeFIG. 4) has an outer diameter that is at least somewhat smaller than the outer diameter of the mandrel16. This means that the end flange44of the bar can follow a deep distance into the deformation tube without being stopped by the same. Depending on the nature of the collision and the size of the shock forces, which are generated in conjunction hereby, the mandrel may penetrate differently deep into the deformation tube before all energy has been extinguished. Thus, in particularly severe cases, the tube may be deformed along the major part of the length thereof.

A substantial advantage of the towing arrangement according to the invention is that the same has an inherent collision protection, which can be realized by structurally simple and inexpensive means. Furthermore, said collision protection function may be integrated in the towing arrangement without the length of the bar projecting from the frame needing to be increased. Thus, the requisite deformation tube can in its entirety be accommodated inside the space already available in the interior of the frame. Another advantage is that the construction of the towing arrangement offers reasonable possibilities of restoring the towing arrangement at low costs after an occurred collision. Thus, it may happen that only the deformation tube is destroyed in connection with the mandrel penetrating into the same and altering the shape thereof during plastic deformation of the material in the tube. However, under favourable circumstances, other components in the arrangement may remain intact, wherein the towing arrangement can be restored to working order by the simple measure of exchanging the deformation tube.

Feasible Modifications of the Invention

The invention is not solely limited to the embodiment described above and shown in the drawings. Thus, the mandrel connected to the bar or the registration arm via the pin may, for instance, be formed in many ways that deviate from the detailed embodiment that has been exemplified in the drawings. The concept “plate”, as this is used in the description as well as the claims, should therefore be interpreted in the widest sense. Hence, instead of an equally thick plate, the front part of the mandrel may have any suitable shape, provided that the part in question is suitable for the recession of a through hole for the pin and for the pressing of shock-absorbing spring members against the same.