End Piece for a Coupling Rod, Draft Gear for a Coupling Rod, Coupler for a Multi-Car Vehicle and Method for Building a Draft Gear or Coupler

This application is the national stage application under 35 U.S.C. § 371 of International Application No. PCT/EP2023/067849 filed Jun. 29, 2023, which claims priority to EP 22182186.1 filed on Jun. 30, 2022, the entire disclosures of which are incorporated herein by reference in their entireties.

The invention pertains to an end piece suitable to be used as part of a draft gear of a coupler for a multi-car vehicle. The invention also pertains to a draft gear for a coupler for a multi-car vehicle. The invention also pertains to a coupler for a multi-car vehicle. The invention also pertains to a method of building a draft gear or a coupler.

From EP 1 719 684 B1, an end piece for a coupling rod is known. The end piece is suitable to be used as part of a draft gear of a coupler for a multi-car vehicle. The draft gear is shown for example inandof EP 1 719 684 B1. The end piece comprises a joint section (“Anlenkung”) configured to be mounted to a car of a multi-car vehicle such that it can rotate about a generally vertical axis. Such joint section comprises a housing that is not further designated in the Figs. of EP 1 719 684 B1. The end piece of EP 1 719 684 B1 has a rod referred to as “Kupplungsschaft 1” or “hinteres Ende des Kupplungsschafts 3”, the rod having a housing part that is arranged inside the housing of the end piece. The end piece, by way of the rubber donuts called “Federringe 13”, has an elastic connection that connects the housing part of the rod to the housing of the end piece. The main purpose of the elastic connection is to absorb shocks acting in the longitudinal direction of the rod during pushing and pulling of the cars of the multi-car vehicle. However, the elasticity of the elastic connection further allows the rod to slightly swivel upwards and downwards relative to the housing of the end piece, thereby compensating minor vertical displacements between two cars which are connected by the coupler. The elasticity of the elastic connection even further enables the rod to swivel about its longitudinal axis relative to the housing, i.e. slightly rotate about its longitudinal axis, when torsional forces are applied to the rod. More specifically, the housing part of the rod has circumferential grooves between circumferential ridges (“Ringwülste 14”) and the housing of the end piece has an inward-facing surface with circumferential grooves arranged between circumferential ridges arranged on the inward-facing surface. The doughnut-shaped elastic elements “Federringe 13” each have an inner part arranged in one of the circumferential grooves of the housing part of the rod and an outer part arranged in one of the circumferential grooves of the inward-facing surface of the housing of the end piece. The draft gear of EP 1 719 684 B1 has a bearing bracket referred to as “Lagerbock 4”, the above-described end piece and a joint (“Drehzapfen 16”) arranged between the bearing bracket and the housing of the end piece, whereby the joint allows the housing to swivel relative to the bearing bracket.

From WO 2019/045634, a coupler for a multi-car vehicle is known, the coupler comprising a main buffermounted between a coupler headand a car body attachment. In order to support the main bufferin an uncoupled state, support dampersare arranged underneath, with a rear end mounted on the car body attachmentand a front end mounted on the main bufferby means of a holder.

From WO 2021/249954 A1, a coupler for a multi-car vehicle is known having a coupling rod which has a first rod part and a second rod part, whereby the coupler head is attached to the second rod part, whereby the coupling rod has a rod joint arranged between the first rod part and the second rod part, the rod joint allowing the second rod part to be folded backwards towards the first rod part. Similar designs are known from EP 3 992 054 A1 and CN 112896224 A. Designs of couplers as shown in WO 2021/249954 A1 have the problem that, in a state where the coupler head is folded backwards (e.g.of WO 2021/249954 A1), the coupler head is arranged off-centre of the longitudinal axis of the first rod part and hence of the draft gear. This leads to the effect that the weight of the coupler head that now is off-centre applies a torsional force onto the first rod part and the draft gear.

From WO 2017/076871 A1 a draft gear for a coupling rod is known. The draft gear has a base plate (Grundplatte) that surrounds the coupler rod (Kupplungsstange). Different from the joint section with a two-part housing as known from EP 1 719 684 B1, which has two housing halves fixed by way of screws (seeof EP 1 719 684 B1), in the design known from WO 2017/076871 A1 the base plate has a one-piece element that has a hole through which the coupler rod passes. A bearing element (Lagerelement) is arranged between the inward-facing surface of the hole of the base plate and the outer circumferential surface of the coupler rod. The bearing element comprises an elastic element (Rueckstellkomponente). An inward-facing surface of the elastic element is arranged on the outer circumferential surface of the coupler rod so as not to rotate relative to the outer circumferential surface of the coupler rod via the design of an end wall of the bearing element (Stuetzkomponente) that sits on the outer circumferential surface of the coupler rod and on which the inward-facing surface of the elastic element sits. An outward-facing surface of the elastic element is arranged to contact the inward-facing surface of the hole of the base plate so as not to rotate relative to the inward-facing surface. A rotational movement of the outward-facing surface of the coupler rod relative to the inward-facing surface of the hole will lead to the elastic element being deformed, whereby the deformation creates a restoring force directed to rotate the coupler rod back.

Given this background, the problem to be solved by the invention is to provide means that reduce asymmetric loads on a draft gear.

This problem is solved by an end piece, a draft gear and a coupler or method according to aspects of the present disclosure. Preferred embodiments are described in the claims and the description following hereafter.

The invention is based on the basic idea of providing the end piece with an additional element which is suitable to create a spreading force. The additional element has a first end that is in contact with a part of the rod and a second end that is in contact with a part of the joint section, such as the afore-mentioned housing of the end piece. According to the invention, a spring element is arranged between the first and second end of the additional element, the spring element generating a spreading force that is directed to again increasing the distance between the first and second end of the additional element, if the first end is moved towards the second end. The invention identifies that a tendency for the rod to swivel about its longitudinal axis relative to the joint section of the end piece, as it may occur in designs as shown in WO 2021/249954 A1 for cases where the coupler head has been folded back, can be countered by providing the additional element that is suitable to create a spreading force as described above. The tendency of the rod to swivel about the longitudinal axis relative to the joint section of the end piece when the coupler head is folded back causes a twisting effect on the elastic connection between the rod and the joint section of the end piece. In the case of the design of EP 1 719 684 B1, the rubber donuts connecting the rod (i.e. the housing part of the rod) with the joint section (i.e. the housing of the end piece) are under constant pressure due to such twisting force. If—as the invention suggests—a spring element is provided that generates a spreading force if a certain part of the rod that is in contact with the first end of the additional element is moved towards the part of the joint section that is in contact with the second end, the rotational movement of the rod about the rod's longitudinal axis relative to the joint section can be countered and the twisting effect is hence at least reduced or even completely countered.

The invention is directed to a new design for an end piece of a coupling rod. It is believed that a new design for such an end piece is a marketable good in itself. The end piece modified according to the invention can, for example, be used as a replacement piece for the end piece that is disclosed as part of the draft gear shown in EP 1 719 684 B1. The bearing bracket (“Lagerbock”) and the joint (“Drehzapfen”) of the design shown in EP 1 719 684 B1 can remain the same if the draft gear according to EP 1 719 684 B1 is modified according to the invention. All key elements of the invention are realized within the end piece. The twisting forces applied to the rod that are to be counteracted by the additional element provided according to the invention are fully offset with the additional element provided to the end piece.

According to the invention, the end piece comprises a joint section configured to be mounted to a car of a multi-car vehicle such that it can rotate about a generally vertical axis.

In a first embodiment, the joint section of the end piece may comprise a housing. This housing can be a unitary body. In a preferred embodiment, the housing is made up of two shells that are connected to one another, for example an upper shell and a lower shell that are screwed together in a horizontal parting plane, e.g. similar to the design of EP 1 719 684 B1. In a preferred embodiment, the housing, preferably the shells that make up the housing, are either machined out of solid pieces or are cast pieces (that after the casting are possibly being further machined). In a preferred embodiment, the housing has a longitudinal shape and extends along a longitudinal axis. The end piece according to the invention further has a rod. The rod may be a coupling rod or a rod attached to a coupling rod. In other words, the rod may be composed of several parts, in particular several rod sections.

In particular, the rod may comprise a shock absorber, e.g. in the form of a hydraulic damper, for absorbing forces acting on the rod during normal operation and/or an energy dissipating structure configured to irreversibly dissipate energy by way of destruction in the case that overly strong forces are acting on the rod, such as in the case of a crash. The shock absorber and/or energy dissipating structure may comprise a cylinder and a piston guided in the cylinder, wherein the cylinder forms one part or section of the rod and the piston forms another part or section of the rod, wherein either one of the two may be connected to the joint section.

In the first embodiment, the rod may have a housing part that is arranged inside the housing of the end piece. The design shown in EP 1 719 684 B1 inshows such a rod which forms the rear part of the coupling rod and which terminates in an enlarged end that can be connected to a further part of the coupling rod. Such a design with a rod section which has the housing part arranged in the housing of the joint section of the end piece allows for the draft gear to be manufactured separately and, once it is finished, for the remainder of the coupling rod and the coupling head to be attached to it. Designs are also feasible, however, where the rod that forms part of the end piece is the coupling rod itself. In such a design, the rod has free end to which the coupler head is connected. In the preferred embodiment, where the coupling rod has a first rod part and a second rod part, wherein the coupler head is attached to the second rod part, a rod joint may be arranged between the first rod part and the second rod part, so as to allow the second rod part to be folded backwards towards the first rod part, in which case the rod of the end piece could form the first rod part. Alternatively, in such a design the first rod part could be attached to the rod of the end piece.

In a second embodiment, the joint section of the end piece may comprise a pin and the rod of the end piece may comprise an opening, such as an eyelet, in which the pin of the joint section is arranged. The pin may have any shape, and the position of such pin on the joint section is not critical. Furthermore, the pin may have a longitudinal axis, which axis may be horizontal or vertical or at an angle between horizontal and vertical, as long as the elastic connection between the pin of the joint section and the opening of the rod allows the rod to swivel upward and downward relative to the joint section of the end piece. Preferably, the pin has a vertical axis.

The elastic connection providing a connection between the pin of the joint section and the opening of the rod may be ring-shaped. More specifically, the elastic connection may comprise an inner metal ring connecting to the pin of the joint section, an outer metal ring connecting to the opening of the rod, and an elastic material, such as rubber, joining the inner and outer metal rings together. Such a three-piece elastic connection can be pre-fabricated easily and fitted in rod opening and on the joint pin, e.g. by means of one or more retaining rings. Preferably, the elastic material is spherical, i.e. it may have at least one, more preferably both, of a spherical outer surface facing the opening of the rod and a spherical inner surface facing the pin of the joint section. The spherical shape of the rubber material and, thus, the corresponding spherical shape of the outer surface of the joint pin or/and inner surface of the opening of the rod enhances the ability of the rod to slightly swivel upwards and downwards when the level between two connected cars of a multi-car vehicle changes.

The end piece according to the invention further has an elastic connection that connects the rod to the joint section, the elasticity of the elastic connection allowing the rod to swivel, inter alia, about its longitudinal axis relative to the joint section. Thus, the swivel-movement is a rotational movement about the longitudinal axis. The elastic connection between the rod and the joint section may be provided between an outer circumferential surface of the rod and an inward-facing surface of the joint section. The elastic connection can be provided by way of rubber material attached to the outer circumferential part of the rod on the one side and the inward-facing surface of the joint section on the other side.

The elastic connection may be provided by way of one or more ring-shaped elastic elements. In the above-mentioned first embodiment, the housing part of the rod has one or several circumferential grooves and the housing of the joint section has an inward-facing surface that has one or several circumferential grooves arranged on the inward-facing surface, whereby the elastic connection comprises one or more ring-shaped elastic elements, each ring-shaped elastic element having an inner part arranged in one of the circumferential grooves of the housing part and an outer part arranged in one of the circumferential grooves of the inward-facing surface of the housing of the joint section.

In the first embodiment, the elastic connection may be provided by way of several elements that each have the shape of a circular ring section. For example, two elements that each have the shape of a circular ring section that spans over 180° may contact each other at their ends to form a ring-shaped elastic element. The individual elements that each have the shape of a circular ring section are sometimes referred to as “banana-shaped” or “telephone receiver”-shaped (in German: “telefonhörerförmig”).

In the first embodiment, the housing part of the rod may have one or several circumferential grooves and the housing may have an inward-facing surface with one or several circumferential grooves arranged on the inward-facing surface, wherein the elastic connection may comprise one or more ring-shaped elastic elements which are each made of a number of elements having the shape of a circular ring section, each such composed ring-shaped elastic element having an inner part arranged in one of the circumferential grooves of the housing part and an outer part arranged in one of the circumferential grooves of the inward-facing surface of the housing of the first joint section.

Such a design is for example shown inof EP 1 719 684 B1 by way of the “Federringe”.

In the first embodiment, at least two circumferential grooves and two ring-shaped elastic elements may be provided (be it two one-piece ring-shaped elements or be it two composite ring-shaped elements, each made of a number of elements having the shape of a circular ring section). Preferably, at least three circumferential grooves and three ring-shaped elastic elements are provided. More preferably, fewer than 15, or even fewer than 10, circumferential grooves and ring-shaped elastic elements are provided.

Preferably, the elastic connection which connects the rod to the joint section has a design which allows the rod to swivel upwards and downwards relative to the joint section of the end piece of the coupler, thereby compensating minor vertical displacements between two cars which are connected by the coupler. The elasticity of the elastic connection further enables the rod to swivel about its longitudinal axis about its longitudinal axis relative to the joint section, i.e. slightly rotate about its longitudinal axis, when torsional forces are applied to the rod. These possible movements of the rod are due to the elasticity of the elastic connection, leading to a deformation of the material that provides the elastic connection. If a rubber material is used as a material for the elastic connection, the swivel movement of the rod about its longitudinal axis relative to the joint section will lead to a deformation of the rubber material. The design can also foresee that, if the swivel movement of the rod about its longitudinal axis relative to the joint section is larger than a predetermined amount, an outward-facing surface of the material which provides the elastic connection (for example the rubber material) and which is initially in surface contact with a surface of the rod or a surface of the joint section, looses such surface contact, e.g. lifts off or slips into a new position of surface contact.

Preferably, the rod is also moveable in a linear direction relative to the joint section at least to a certain degree, i.e. in the direction of the rod's longitudinal axis. This may also be enabled by the elastic connection, in particular when the elastic connection is made from an elastic material, such as rubber. Thus, in a preferred embodiment, the elastic connection allows the rod not only to swivel about its longitudinal axis relative to the housing but also to move along the rod's longitudinal axis relative to the housing at least to a certain degree.

According to the invention, the end piece is provided with at least one spreading element. The spreading element is arranged separately from the elastic connection that connects the rod to the joint section of the end piece. In a preferred embodiment, the spreading element is arranged outside of the joint section. The spreading element is suitable to create a spreading force. According to the invention, the spreading element has a first end which is in contact with a part of the rod. In a preferred embodiment, the first end is fixedly connected to a part of the rod. In a preferred embodiment, a mounting plate is provided on the outer circumference of the rod and the first end of the spreading element may be part of the mounting plate. In a preferred embodiment, the first end of the spreading element, e.g. the mounting plate, is attached to the rod in a releasable manner. For example, the first end of the spreading element, or the mounting plate comprising the first end, can be screwed to the outer circumference of the rod, allowing maintenance to the element should the element become damaged. Alternatively, the first end of the spreading element, or the mounting plate comprising the first end, may be welded to the rod.

According to the invention, the spreading element has a second end which is in contact with a part of the joint section. In a preferred embodiment, the second end of the additional element is formed by a free surface which is in surface contact with a part of the joint section. In a preferred embodiment, the second end that is in contact with a part of the joint section can slide along a surface of the joint section.

Accordingly, in a preferred embodiment, the first end of the spreading element is fixedly, but preferably releasably, attached to a part of the rod, while the second end of the spreading element is in surface contact with a part of the joint section, but not attached to a part of the joint section. Such a design, where the spreading element is attached to the rod, but only in surface contact with the joint section allows for movements of the rod to take place relative to the joint section along the longitudinal axis of the rod.

According to the invention, a spring element is arranged between the first end and second end of the spreading element, the spring element generating the spreading force that is directed to increase the distance between the first end and second end of the spreading element when the first end is moved towards the second end. In a preferred embodiment, the spring element is designed and arranged in such a manner that starting from an initial position, where the spring element might be relaxed or might be loaded to a smaller extent, the spring element is loaded or loaded further when the first end is moved towards the second end. (Further) loading the spring element leads to the spring element providing the spreading force. Preferably, the spring element is arranged in such a manner that the spring force is directed in a plane perpendicular to the longitudinal axis of the rod, preferably in a tangential direction relative to a circular shaped outer circumference of the rod, where the rod—in a preferred embodiment—is designed to have such a circular shaped outer circumference.

The spring element may be a damper, for example a gas hydraulic damper. In a preferred embodiment, the spring element is a spring. The spring element can for example be a coil spring. Preferably, the spring element is a disc spring or a series of disc springs arranged along a line.

Designs of the spreading element are feasible, in which the parts of the spreading element are uncovered. As suggested above, the first end of the additional element can be provided by a mounting plate which is attached to a part of the rod. In the simplest design, a coil spring is attached to this mounting plate, wherein the free end of the coil spring forms the second end of the spreading element, the second end being in surface contact with a part of the joint section.

However, the spring element is preferably arranged within a housing. Given the dirty environments of couplers for multi-car vehicles, for example on trains, the risk exists that the spring element may become dirty and lose its functionality. Therefore, in a preferred embodiment, the spreading element has a spreading element housing with a chamber, wherein the chamber has a chamber end wall. A spreading element rod is arranged so as to be at least partially arranged in the chamber and movable relative to the chamber end wall. In a preferred embodiment, the spring element is arranged at least partially, preferably completely, inside the chamber. The spring element is preferably arranged between the chamber end wall and a holding part of the spreading element rod. The holding part of the spreading element rod can be a fixed connection between an end of the spring element and the spreading element rod. For example, a straight end piece of a coil spring may be inserted into a hole of the spreading element rod, the hole hence forming the holding part of the spreading element rod and the coil spring, in this embodiment, being arranged between the chamber end wall and this hole of the spreading element rod, with the straight end piece of the coil spring arranged in the hole. In a different embodiment, the holding part is a protruding part that protrudes over other parts of the surface of the spreading element rod. Such a protruding part can be a simple pin that protrudes radially over other parts of the surface of the spreading element rod. Preferably, the protruding part is a rim that circumferentially extends around the remaining parts of the spreading element rod and protrudes radially outward from these remaining parts of the spreading element rod. Such a rim provides a good counter surface for the spring element.

In a preferred embodiment, the spring element comprises one disc spring or several disc springs, wherein the one disc spring or several disc springs are arranged between the chamber end wall and a holding part which radially extends from the spreading element rod, preferably a rim shaped holding part which radially extends from the spreading element rod.

In a preferred embodiment, the rim-shaped protruding element that forms the holding part of the spreading element rod has a circumferential sealing element arranged around its most outward end. Said sealing element is arranged to seal against the wall of the chamber of the spreading element. With the spring element arranged within the chamber and with the sealing element sealing against the circumferential wall of the chamber, the sealing element prevents dirt from entering into the chamber and from coming into contact with the spring element.

The spreading element rod is designed to be movable relative to the chamber end wall. In a preferred embodiment, the chamber end wall has a through-hole and the spreading element rod is arranged so as to extend through the through-hole. In a preferred embodiment, a blocking element is arranged on that part of the spreading element rod which is arranged outside of the chamber, the blocking element stopping the spreading element rod from being pulled through the through-hole. Such a blocking element may be a nut which is screwed onto an external threading provided on an end of the spreading element rod.

In a preferred embodiment, however, a threading is provided in the spreading element rod as an internal threading and extends from an end of the spreading element rod along the longitudinal axis of the spreading element rod, wherein a screw is screwed into the thread and wherein the second end of the spreading element is provided by a surface of the head of the screw. Designs are feasible where a free end of the spreading element rod provides the second end of the spreading element which is in contact with a part of the joint section, preferably in a surface contact with a part of the joint section, and preferably able to slide along that part of the joint section. However, providing a screw screwed into a thread of the spreading element rod allows the spreading element to be better adapted to its environment. By way of screwing the screw further into the threading or by way of screwing the screw out of the threading, the length of the spreading element rod including the screw can be changed. This design allows the spreading element to be adapted to individual construction scenarios and especially to compensate tolerances

In a preferred embodiment, a locking screw may be provided in a radially extending internal threading of the spreading element rod and terminate in the internal threading that takes up the screw. Said locking screw may be used to lock the position of the screw in the threading.

In a preferred embodiment, a second spreading element which is suitable to create a spreading force is provided, the second spreading element having

In a preferred embodiment, the first end of the first spreading element is in contact with a first part of the rod and the first end of the second spreading element is in contact with a second part of the rod, the first part of the rod being arranged on a first side of the rod and the second part of the rod being arranged on a second side of the rod, the second side being the opposite side of the first side. For example, the first end of the first spreading element may be in contact with an upper part of the rod, while the first end of the second spreading element may be in contact with a lower part of the rod. Or the first end of the first spreading element may be in contact with a left-facing part of the rod, when viewed along the longitudinal axis of the rod, and the first end of the second spreading element may be in contact with a right-facing part of the rod, when viewed along the longitudinal axis of the rod.

In a preferred embodiment, the second end of the first spreading element is in contact with a first part of the joint section and the second end of the second spreading element is in contact with a second part of the joint section, the rod being arranged between the first part of the joint section and the second part of the joint section. In a preferred embodiment, the first part of the joint section is arranged on one side of a vertical plane that contains the longitudinal axis of the rod and the second part of the joint section is arranged on the opposite side of such a vertical plane. In addition or as an alternative, the first part of the joint section is arranged on one side of a horizontal plane that contains the longitudinal axis of the rod and the second part of the joint section is arranged on the other side of such a horizontal plane.

The draft gear according to the invention comprises

In this preferred embodiment, the joint may comprise:

In a preferred embodiment, the upper joint pin and the lower joint pin are formed by a single joint pin. In the above-mentioned second embodiment, where a pin of the joint section of the end piece is arranged in an opening or eyelet of the rod, the pin may be formed by such single joint pin.

Preferably, the upper bracket and the lower bracket each have a break-away section, said break-away section containing the hole. The break-away section may extend through an opening in the bearing bracket to a plate which is screwed to the back of the bearing bracket. The screws can be designed to break upon the application of a certain linear force, wherein breaking away of the screws sets free the plate and the break-away sections, thereby allowing the end piece to move relative to the remainder of the bearing bracket.

In a preferred embodiment, the longitudinal axis of the rod is a horizontal axis.

In a preferred embodiment, the spreading element rod extends along a longitudinal axis which is a horizontal axis. In a preferred embodiment, the—preferably horizontal—longitudinal axis of the spreading element rod is arranged in a first vertical plane and the—preferably horizontal—longitudinal axis of the rod is arranged in a second vertical plane, wherein an angle between the first vertical plane and the second vertical plane is >0° and <180°, preferably>25° and <150°, more preferably>45° and<135°, and most preferably 90°.

The coupler according to the invention comprises a draft gear according to the invention and a coupler head attached to the rod of the end piece of the draft gear.

In a preferred embodiment, the rod of the coupler has a first rod part and a second rod part, wherein the first rod part is directly or indirectly connected to the joint section, and wherein the coupler head is attached to the second rod part and wherein the rod has a rod joint arranged between the first rod part and second rod part, the rod joint allowing the second rod part to be folded backwards towards the first rod part.

In the method according to the invention a draft gear according to the invention or a coupler according to the invention is built, wherein the term “built” includes the new building of a draft gear or a coupler during rehaul or repair of the draft gear. The method comprises the steps of:

In a preferred embodiment, the multi-car vehicle is a train.

show a first embodiment of a draft gearwith a rod, which rodmay form part of a coupling rod. The draft gearcomprises a bearing bracketsuitable to be attached to a car of a multi-car vehicle. The draft gearfurther comprises an end piece. A jointis arranged between the bearing bracketand the end piece, the jointbeing formed by a first joint section of the end pieceand a second joint section of the bearing bracket. The jointallows the end pieceto swivel about a vertical axis A relative to the bearing bracket.