[0001] 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.

[0002] From EP 1 719 684 Bl, 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 in Fig. 5 and Fig. 6 of EP 1 719 684 Bl. 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 Bl. The end piece of EP 1 719 684 Bl 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 (“Ringwiilste 14”) and the housing of the end piece has an inward-facing surface with circumferential grooves arranged between circumferential ridges arranged on the inwardfacing 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 Bl 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. [0003] From WO 2019/045634, a coupler for a multi-car vehicle is known, the coupler comprising a main buffer 2 mounted between a coupler head 4 and a car body attachment 5. In order to support the main buffer 2 in an uncoupled state, support dampers 3 are arranged underneath, with a rear end mounted on the car body attachment 5 and a front end mounted on the main buffer 2 by means of a holder 6.

[0004] From WO 2021/249954 Al, 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 Al and CN 112896224 A. Designs of couplers as shown in WO 2021/249954 Al have the problem that, in a state where the coupler head is folded backwards (e.g. Fig. 1 of WO 2021/249954 Al), 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.

[0005] From WO 2017/076871 Al a draft gear for a coupling rod is known. The draft gear has a base plate (Grundplatte 20) that surrounds the coupler rod (Kupplungsstange 10). Different from the joint section with a two-part housing as known from EP 1 719 684 Bl, which has two housing halves fixed by way of screws (see Fig. 4,5 of EP 1 719 684 Bl), in the design known from WO 2017/076871 Al the base plate has a one-piece element that has a hole through which the coupler rod passes. A bearing element (Lagerelement 30) 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 32). 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 31) 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 outwardfacing 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. [0006] Given this background, the problem to be solved by the invention is to provide means that reduce asymmetric loads on a draft gear.

[0007] This problem is solved by an end piece, a draft gear and a coupler or method according to the appending independent claims. Preferred embodiments are described in the subordinate claims and the description following hereafter.

[0008] 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 Al 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 Bl, 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.

[0009] 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 Bl. The bearing bracket (“Lagerbock 4”) and the joint (“Drehzapfen 16”) of the design shown in EP 1 719 684 Bl can remain the same if the draft gear according to EP 1 719 684 Bl 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.

[00010] 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.

[00011] 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 Bl. 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.

[00012] 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.

[00013] 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 Bl in Figs. 4 to 6 shows 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.

[00014] 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.

[00015] 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.

[00016] 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.

[00017] 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 inwardfacing 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.

[00018] 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: “telefonhbrerfbrmig”).

[00019] 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 ringshaped 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.

[00020] Such a design is for example shown in Fig. 6 of EP 1 719 684 Bl by way of the “Federringe 13”.

[00021] In the first embodiment, at least two circumferential grooves and two ringshaped 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.

[00022] 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.

[00023] 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.

[00024] 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.

[00025] 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.

[00026] 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.

[00027] 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. [00028] 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.

[00029] 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.

[00030] 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.

[00031] 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.

[00032] 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.

[00033] 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.

[00034] 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.

[00035] 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.

[00036] In a preferred embodiment, a second spreading element which is suitable to create a spreading force is provided, the second spreading element having a first end which is in contact with a part of the rod, a second end which is in contact with a part of the joint section of the end piece, and a spring element arranged between the first end and second end of the second spreading element, the spring element generating a spreading force which is directed to increasing the distance between the first end and second end of the second spreading element when the first end of the second spreading element is moved towards the second end of the second spreading element.

[00037] 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.

[00038] 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. [00039] The draft gear according to the invention comprises a bearing bracket suitable to be attached to a car of a multi-car vehicle and having a (second) joint section, an end piece according to the invention as described above and

[00040] a joint arranged between the rod of the end piece and the bearing bracket and comprising the (first) joint section of the end piece, e.g. in the form of a joint pin (7), and the (second) joint section of the bearing bracket, e.g. in the form of an opening in which the joint pin is arranged, wherein the joint allows the (first) joint section of the end piece - and thus the rod - to swivel relative to the bearing bracket about a substantially vertical axis. In a preferred embodiment, the second joint section of the bearing bracket has an opening and the first joint section of the end piece is arranged partially within said opening, e.g. by means of a joint pin.

[00041] In this preferred embodiment, the joint may comprise: an upper joint pin protruding from the top of the first joint section of the end piece along a vertical axis, the upper joint pin being held in a hole of an upper bracket of the bearing bracket such that the upper joint pin can swivel in the hole about the vertical axis, and a lower joint pin protruding from the bottom of the first joint section of the end piece in the direction of the vertical axis, the lower joint pin being held in a hole of a lower bracket of the bearing bracket such that the lower joint pin can swivel in the hole about the vertical axis.

[00042] 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.

[00043] 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.

[00044] In a preferred embodiment, the longitudinal axis of the rod is a horizontal axis.

[00045] 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°.

[00046] 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.

[00047] 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.

[00048] 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: providing a draft gear according to the invention or a coupler according to the invention, removing at least one spreading element from the draft gear, providing a corresponding spreading element for replacing the removed spreading element, and attaching the corresponding spreading element to the draft gear.

[00049] In a preferred embodiment, the multi-car vehicle is a train. [00050] In the following, the invention will be described by reference to the appending drawings which show only exemplary embodiments. In the drawings:

Fig. 1 shows a schematic perspective view onto a draft gear according to a first embodiment;

Fig. 2 shows a sectional side view through parts of the draft gear according to Fig.

1;

Fig. 3 shows a sectional front view through parts of the draft gear according to Fig.

1;

Fig. 4 shows a perspective schematic view onto a detail of the draft gear shown in

Fig. 1;

Fig. 5 shows a schematic perspective view onto a draft gear according to a second embodiment;

Fig. 6 shows a sectional side view through parts of the draft gear according to Fig.

5;

Fig. 7 shows a sectional front view through parts of the draft gear according to Fig.

5;

Fig. 8 shows a perspective schematic view onto a coupler comprising a draft gear.

[00051] Figs. 1 to 4 show a first embodiment of a draft gear 1 with a rod 13, which rod 13 may form part of a coupling rod 2. The draft gear 1 comprises a bearing bracket 3 suitable to be attached to a car of a multi-car vehicle. The draft gear 1 further comprises an end piece 4. A joint 5 is arranged between the bearing bracket 3 and the end piece 4, the joint 5 being formed by a first joint section of the end piece 4 and a second joint section of the bearing bracket 3. The joint 5 allows the end piece 4 to swivel about a vertical axis A relative to the bearing bracket 3.

[00052] In the first embodiment shown in Figs. 1 to 4, the first joint section comprises an upper joint pin 7 protruding from the top of a housing 6 of the first joint section in the direction of the vertical axis A, the upper joint pin 7 being held in the second joint section of the bearing bracket 3, the second joint section being partly formed by a hole 8 in an upper bracket 9 of the bearing bracket 3, such that the upper joint pin 7 can swivel in the hole 8 about the vertical axis A, and

[00053] a lower joint pin 10 protruding from the bottom of the housing 6 in the direction of the vertical axis A, the lower joint pin 10 being held in another hole 11 in a lower bracket 12 of the bearing bracket 3, such that the lower joint pin 10 can swivel in the hole 11 about the vertical axis A.

[00054] The upper bracket 9 and the lower bracket 12 can be designed to have a breakaway section 44 each, said break-away section 44 containing the holes 8, 11. The break-away section 44 can extend through an opening 45 in the bearing bracket 3 to a plate 46 that is screwed to the back of the bearing bracket 3. The screws (not shown in Fig. 1) can be designed to break upon the application of a certain linear force. Breaking away of the screws sets free the plate 46 and the break-away sections 44, thereby allowing the end piece 4 to move relative to the remainder of the bearing bracket 3.

[00055] The end piece 4 comprises the housing 6 and a rod 13, which in the embodiment shown in Figs. 1 to 4 is a detachable end piece of the coupler rod 2. The rod 13 has a housing part 14 that is arranged inside the housing 6. An elastic connection 15 connects the housing part 14 to the housing 6. The elasticity of the elastic connection 15 allows the rod 13 to swivel about its longitudinal axis B relative to the housing 6. The swivel movement is a rotational movement around the longitudinal axis B as indicated by the arrow C in Fig. 1.

[00056] The housing part 14 of the rod 13 has circumferential grooves 16, and the housing 6 has an inward-facing surface with circumferential grooves 17 arranged on the inward-facing surface. The elastic connection 14 comprises ring-shaped elastic elements 18. Each ring-shaped elastic element 18 has an inner part arranged in one of the circumferential grooves 16 of the housing part 14 and an outer part arranged in one of the circumferential grooves 17 on the inward-facing surface of the housing 6.

[00057] The end piece 4 has a first spreading element 20 and a second spreading element 21, each being suitable to create a spreading force F. The first spreading element 20 has a first end 22 that is connected to a part of rod 15 by way of a screw 23. The first spreading element 20 also has a second end 24 which is in surface contact with a part of the housing 6. As part of the first spreading element 20, a spring element 25 is arranged between the first end 22 and the second end 24, the spring element 25 generating a spreading force F which is directed to increasing the distance between the first end 22 and the second end 24 when the first end 22 is moved towards the second end 24. The first end 22 comprises two perpendicular or substantially perpendicular contact surfaces, wherein one of said contact surfaces is parallel to or substantially parallel to a surface of the second end 24 and the second one is used to connect to the rod. [00058] The element 21 is designed in the same manner as the element 20 and hence has a first end 22 which is connected to a part of the rod 13 by way of a screw 23. The element 21 likewise has a second end 24 that is in surface contact with a part of the housing 6. As a part of the element 21, a spring element 25 is arranged between the first end 22 and the second end 24, the spring element 25 generating a spreading force F which is directed to increasing the distance between the first end 22 and the second end 24 when the first end 22 is moved towards the second end 24.

[00059] The spreading element 20, 21 has a spreading element housing 26 with a chamber 27, whereby the chamber 27 has a chamber end wall 28. A spreading element rod 29 is partially arranged in the chamber 27 and moveable relative to the chamber end wall 28. The spring element 25 is arranged between the chamber end wall 27 and a holding part 30 of the spreading element rod 29. In the embodiment of Fig. 1 to 4, the spring element 25 comprises several disc springs 31. The disc springs 31 are arranged between the chamber end wall 27 and a holding part 30 which, in the embodiment of Fig. 1 to 4, radially extends from the spreading element rod 29.

[00060] As can best be seen in Fig. 3, an internal threading 32 is provided in the spreading element rod 29 and extends from an end of the spreading element rod 29 along the longitudinal axis C of the spreading element rod 29, whereby a screw 33 is screwed into the threading 32. The screw 33 has a head. The second end 24 is provided by an end surface of the head of the screw 33. A lock screw 40 can be used to lock the position of the screw 33 in the threading 32.

[00061] As can best be seen in Fig. 3, the first end 22 of the first spreading element 20 is in contact with a first part of the rod 13, and the first end 22 of the second spreading element 21 is in contact with a second part of the rod 13, the first part of the rod 13 being arranged on a first side of the rod 13 (in the embodiment of Fig. 3 on the top of the rod 13; which can also be described as being on one side of a horizontal plane that contains the longitudinal axis B of the rod 13) and the second part of the rod 13 being arranged on a second side of the rod 13 (in the embodiment of Fig. 3 on the bottom of the rod 13; which can also be described as being on another side of a horizontal plane that contains the longitudinal axis B of the rod 13), the second side being the opposite side to the first side.

[00062] As can best be seen in Fig. 3, the second end 24 of the element 20 is in contact with a first part of the housing 6, and the second end 24 of the further element 21 is in contact with a second part of the housing 6, the rod 13 being arranged between the first part of the housing 6 and the second part of the housing 6. The arrangement can also be described such that the first part of the housing 6 is arranged on one side of a vertical plane that contains the longitudinal axis B of the rod 13 and the second part of the housing 6 is arranged on the opposite side of this vertical plane.

[00063] As can best be seen in Fig. 1, the housing 6 may be made up of an upper shell 34 and a lower shell 35 which are screwed together by screws 33. The housing 6 may have a recess 36 adapted to receive the spreading element housing 26 when the rod 13 is made to move linearly relative to the housing 6 for a certain distance.

[00064] The part of the housing 6 with which the second end 24 of the first spreading element 20 is in contact (the end surface of the screw 33) may be a plate 38 protruding from the remainder of the housing 6. The plate 38 may have a wear plate 39 of a plastic material attached to it to facilitate movement of the second end 24 relative to the housing 6. Fig. 1 and 4 show that the wear plate 39 may have a chamfered front edge which facilitates that the head of the screw 33 comes into contact with the wear plate 39 in situations where in certain driving conditions the rod 13 moves out of the housing 6 so much that the head of the screw 33 leaves contact with the wear plate 39.

[00065] Fig. 3 shows that the head of the screw 33 may have a crowned surface which forms the second end 24.

[00066] Figs. 1, 3 and 4 best show that a threading may be provided on the spreading element rod 29 at the end opposite the second end 24. A nut 41 with a locking screw 42 arranged in the nut 41 may be arranged on the threading. The nut 41 may be used to define the position of the spreading element rod 29 relative to the spreading element housing 26 and for pre-tensioning of the disc springs 31. As can also be seen from Fig. 3, the chamber end wall 28 may have a hole through which the spreading element rod 29 passes from inside the chamber 27 to the outside of the chamber 27. The nut 41 is arranged on that part of the spreading element rod 29 which is outside the chamber 27.

[00067] The holding part 30 which, in the embodiment of Fig. 1 to 4, extends radially from the spreading element rod 29 may be used to seal the open end of the chamber 27 by way of arranging a circular sealing element, such as a wearing ring 43, on an outer ringshaped circumferential surface of the holding part 30. The wearing ring 43, however, does not achieve a fluid tight seal as there remains a small gap, but the gap is sufficiently small to prevent dirt, dust, grease, etc. from entering the chamber 27.

[00068] Figs. 5 to 7 show a second embodiment of a draft gear 1 with a rod 13, which rod 13 consists of two rod sections 13D and 13E and which may form part of a longer coupling rod 2. The draft gear 1 comprises a bearing bracket 3 suitable to be attached to a car of a multi-car vehicle. The draft gear 1 further comprises an end piece 4. A joint 5 is arranged between the bearing bracket 3 and the end piece 4, the joint 5 being formed by a first joint section of the end piece 4 and a second joint section of the bearing bracket 3. The joint 5 allows the end piece 4 to swivel about a vertical axis A relative to the bearing bracket 3. As is shown in Fig. 6, the end piece 4 comprises a joint pin 7 which forms the (first) joint section of the joint 5. The joint pin 7 has a vertical axis A so that the end piece 4 with the rod 13 can journal about such vertical axis A of the joint 5 when the multi-car vehicle drives along a curve.

[00069] The rod 13, more specifically the rod section 13E of the rod 13, of the end piece 4 comprises an opening 13 A in the form of an eyelet in which the joint pin 7 of the end piece 4 is mounted and further comprises an elastic connection 15 which provides a connection between the joint pin 7 and the opening 13 A of the rod 13. Thus, in this second embodiment the joint pin 7 of the end piece 4 has two functions, namely serving - together with a corresponding bearing in the bearing bracket 3 - as a pivot about which the coupling rod 2 can rotate and serving as a mounting pin for mounting the rod 13 to the end piece 4 by means of the interposed elastic connection 15.

[00070] The elastic connection 15 providing the connection between the joint pin 7 of the (first) joint section and the opening 13 A of the rod 3 is ring-shaped. More specifically, the elastic connection 15 has an inner metal ring 15A connecting to the joint pin 7, an outer metal ring 15C connecting to the opening 13A of the rod 13, and an elastic material 15B, such as rubberjoining the inner and outer metal rings 15 A, 15C together. This three-piece elastic connection 15 is held in the rod opening 13 A by means of two retaining rings 15D. The elastic material 15B is spherical, i.e. it has a spherical outer surface facing the opening 13A of the rod 13 and a spherical inner surface facing the joint pin 7. The elastic material 15B enables the rod 13 to slightly swivel upwards and downwards when the level between two connected cars of a multi-car vehicle changes. [00071] The elastic material 15B is relatively thin and, thus, does not allow much movement of the end piece 4 relative to the bearing bracket 3 in an axial direction, i.e. in the longitudinal direction of the rod 13. In other words, the damping function of the elastic connection 15 is very limited as compared to the elastic connection 15 of the first embodiment. Therefore, in this second embodiment, the rod section 13 E comprises a shock absorber, e.g. in the form of a hydraulic damper, for absorbing forces acting axially on the rod during normal operation. In addition, the rod section 13 E comprises 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. The shock absorber and/or energy dissipating structure are not shown herein in further detail and may comprise a cylinder and a piston guided in the cylinder. In the embodiment shown, the cylinder forms part of the rod section 13E and the piston forms part of the rod section 13D.

[00072] A spreading element 20 is mounted on the rod 13 so as to create a spreading force between the rod 13 and the (first) joint section comprising the joint pin 7. In the embodiment shown, the spreading element 20 is mounted on the rear rod section 13E of the rod 13, which rod section includes the shock absorber. However, since the front rod section 13D is connected to the rear rod section 13E in such a way that the two rod sections 13D, 13E cannot rotate relative to each other, the spreading element 20 may likewise be mounted on the front rod section 13D. As in the first embodiment described above, the spreading element 20 counteracts any torsional movement of the rod 13 about the rod’s longitudinal axis relative to the joint section/joint pin 7. In this second embodiment, the spreading element is likewise mounted on the rod 13 (here on the rod section 13E) and in contact with an element of the joint section, namely with plate 38 shown in Fig. 5 which is in some way fixedly connected to the joint pin 7, so as to transfer such counter acting forces of the spreading element between the rod 13 and the joint section/joint pin 7.

[00073] The spreading element 20 is shown in a cross-sectional view in Fig.7. The structure of the spreading element 20 in this second embodiment is basically identical to the structure of the spreading elements 20, 21 in the first embodiment. More specifically, the view of the spreading element 20 as shown in Fig 7 corresponds to the view of the lower spreading element 21 as shown in Fig. 3. Thus, the spreading element 20 has a first end 22 that is connected to the rod section 13E by welding, but may likewise be connected by way of a screw 23 as in the first embodiment (see Fig. 4). The spreading element 20 also has a second end 24 which is in surface contact with a part of the joint section, namely with a wear plate 39 mounted to the plate 38 of the joint section. As part of the spreading element 20, a spring element 25 is arranged between the first end 22 and the second end 24, the spring element 25 generating a spreading force F which is directed to increasing the distance between the first end 22 and the second end 24 when the first end 22 is moved towards the second end 24. The first end 22 comprises two perpendicular or substantially perpendicular contact surfaces, wherein one of said contact surfaces is parallel to or substantially parallel to a surface of the second end 24 and the second one is used to weld the spreading element 20 to the rod section 13E.

[00074] Fig. 8 shows a coupler 100 according to the invention. The coupler 100 has a draft gear 1 according to the invention and a coupling rod 2, of which the rod 13 forms a part. A coupler head 101 is attached to the coupling rod 2. In the embodiment shown in Fig. 8, the coupling rod 2 has a first rod part 2a and a second rod part 2b, wherein the first rod part 2a is attached to the rod 13 of the end piece 4. The coupler head 101 is attached to the second rod part 2b, wherein the coupling rod 2 has a rod joint 102 arranged between the first rod part 2a and second rod part 2b, the rod joint 102 allowing the second rod part 2b to be folded backwards towards the first rod part 2a.

[00075] The coupler 100 may be brought into its operational state by aligning the first rod part 2a and the second rod part 2b into a straight line (not shown in Fig. 8). The coupler 100 also has a non-operational state shown in Fig. 8. In the non-operational state, the second rod part 2b has been swivelled to the side about the rod joint 102. The weight of the second rod part 2b and the weight of the coupler head 101 in the non-operational state are out of line relative to the longitudinal axis B and hence create a momentum around the longitudinal axis B, which momentum is directed to rotate the rod 13 about the longitudinal axis B. The spreading force F created by the first spreading element 20 and the second spreading element 21 at least partially counteracts this momentum.

[00076] However, even when the torsional forces are counteracted by the spreading elements 20, 21 when the coupler head 101 is folded back, the weight of the coupler head 101 may still cause downward movement of the rod 13 as well as movements towards the side due to centrifugal forces when the multi-car vehicle is driving along a curve. In order to keep the rod 13 straight relative to the end piece 4, the end piece 4 comprises a wear plate 39A on both lateral sides of the rod 13, as specifically shown in Fig. 7 in relation to the second embodiment.