Coupler arrangement for a rail vehicle

Abstract

A coupler arrangement for a rail vehicle, comprising a coupler head (1), such as a Scharfenberg-type coupler head, and an electrically driven uncoupling device (14) with an uncoupling actuator (15) arranged to move, upon supply of electric energy to the uncoupling device (14), from a first actuator position to a second actuator position, thereby causing a locking device (7) of the coupler head (1) to rotate from its coupled position to its uncoupled position against a spring force provided by a tension spring (10) in the coupler head (1). The arrangement is such that shutting off the supply of electric energy to the uncoupling device (14) allows, or even causes, the uncoupling actuator (15) to return to the first actuator position.

Description

FIELD OF THE INVENTION

[0001] This invention relates to a coupler arrangement for a rail vehicle, in particular for automatic coupling systems (AC) and digital automatic coupling systems (DAC) in rail freight transportation (RFT).BACKGROUND OF THE INVENTION

[0002] An analysis of worldwide RFT activities which was conducted by Berlin University of Technology for the German Federal Ministry of Transport and Digital Infrastructure (BMVI) and published on 29 June 2020 as "Development of a concept for the EU-wide migration to a digital automatic coupling system (DAC) for rail freight transportation" (generally referred to as Technical Report "DAC Technology") showed that the couplings currently used in RFT (Janney and SA3) create only the mechanical connection between the wagons automatically. The BMVI proposes that the European rail freight sector upgrades from a screw coupling (SC) to a DAC Type 4. A DAC Type 4 permits automatic coupling of compressed air, electrical power, and data lines, in addition to the mechanical connection.

[0003] One type of a DAC is the Scharfenberg-type coupling which is, however, not used in RFT so far but is the standard for high-speed rail transportation in Europe. Scharfenberg-type couplings are also available as DAC Type 4. The coupler heads of a Scharfenberg-type coupling have a coupling profile with a cone and a cup, the cone of one coupler head being guided into and centered in the cup of the opposing coupler head during the coupling process, thereby aligning the two coupler heads. Each coupler head contains a rotating metal disc, also known as "hook plate", which is sometimes also referred to as the heart of the coupler head. The disc is fixedly mounted to a main pin which can rotate about a main axis together with the hook plate. A plunger, also referred to as "coupling link" or "hoop", is pivotably mounted to one side of the disc with one of its ends. On the opposing side of the disc, there is a "notch" in the disc. The rotatable disc is held in position by at least one tension spring, in which position the notch is drawn into and the hoop urged outwards of the coupler head. This is also referred to as the "coupled position" of the coupler head.

[0004] There are two general concepts of Scharfenberg-type couplings, a single position coupling and a dual position coupling. In the single position coupling, the "coupled position" of the disc corresponds to the "ready-to-couple position" of the disc. Here, during coupling, when the hoop of one coupler head is pressed with its free end against the disc of the opposing coupler head while the disc is in the ready-to-couple position, its own disc is caused to rotate. Since the coupler heads are identical, such rotation of the disc occurs on both coupler heads simultaneously until the hoops of both coupler heads engage with the notch in the disc of the respective other coupler head. The discs then automatically return to their original position, which is now the coupled position, due to the spring force of the tension spring, and then the coupling process is complete. In the coupled position, the hoops and the virtual lines connecting their respective ends on the discs form a parallelogram. This way, half of the tensile forces acting on the coupler head during regular use is transmitted by each hoop. Uncoupling of the coupler heads requires an external force in order to turn the disc of one of the coupler heads against the spring force into an "uncoupled position" until the hoop of the coupler head slides out of the notch in the disc of the other coupler head. Since the disc of the other coupler head follows such movement, actuating the uncoupling mechanism of one coupler head simultaneously unlocks both coupler heads.

[0005] A dual position coupling differs from the single position coupling in that it includes a latching mechanism which, when the coupler head is being uncoupled against the spring force, holds the disc in the uncoupled position. This way, the hoop of one coupler head can immediately engage with its free end into the notch of the disc of the respective other coupler head at the time when the coupler heads come in contact. The locking mechanism is automatically released mechanically when the two coupler heads approach each other so that the spring force of the tension springs causes the discs to rotate towards their respective coupled position. Thus, in a dual position coupling, the "ready-to-couple position" of the disc corresponds to the disc's "uncoupled position".

[0006] The present invention is particularly useful in connection with Scharfenberg-type couplings, both single and dual position couplings, in particular according to EN16019:2014, but is likewise useful for other couplings, in particular those in which a locking force needs to be overcome in order to release the coupling.

[0007] US 4,366,911 discloses a single position Scharfenberg-type coupling which includes an electromechanical uncoupling mechanism. A lever is fixedly attached to the main pin, and a roller, which is eccentrically mounted on a rotating plate, can be moved by rotation of the rotating plate so that it engages the lever and thereby rotates the disc about the main axis from its coupled position (or ready-to-couple position) to its uncoupled position. Upon further rotation of the rotating plate, the roller disengages from the lever so that the disc can return to its ready-to-couple position urged by the spring force of the tension spring. Meanwhile, the rotating plate rotates further towards its initial position so that it is ready for the next uncoupling process. The rotation of the rotating plate is achieved by means of an electric motor. A sensor is provided to stop the electric motor when the rotating plate has reached its initial position.

[0008] WO 2022 / 129021 A1 relates to a dual position Scharfenberg-type coupling and discloses various kinds of electromechanical uncoupling mechanisms. Here, an electrically actuated element of the uncoupling mechanism engages with the disc so as to rotate the disc about the main axis from its coupled position to its uncoupled or ready-to-couple position. Once the uncoupled or ready-to-couple position has been reached, the disc is held in place in that position by means of a separate latching mechanism until, during the next coupling process, such latching mechanism is released by an approaching second coupler head. In a first mode, however, the return of the disc to the coupled position is blocked as long as the electrically actuated element is not actively moved back towards its starting position. In a second mode, the electrically actuated element is actively moved back to its starting position immediately after the coupled or ready-to-couple position has been reached. The return of the electrically actuated element to its starting position is achieved in either case by electrically actuating the uncoupling mechanism in an opposite direction. A controller is provided to switch between the first mode and the second mode.

[0009] The first mode in which the uncoupling mechanism is blocked in the uncoupled position is helpful on shunting yards where the wagons are pushed uphill and where, after the top of the hump is reached, different wagons can be rolled downhill on a track by gravity. This kind of management is particularly important in the handling of freight wagons. Hereinafter, the state of the coupler head in which the coupler head is uncoupled and not-ready-to-couple is also referred to as "buff state" or "buffer state", and the respective position of the disc is the "buff position" or "buffer position". In this position of the disc the coupler head is prevented from recoupling.SUMMARY OF THE INVENTION

[0010] It is an object of the present invention to simplify a coupler head, in particular a coupler head of the Scharfenberg-type as outlined above, in which the uncoupling process is carried out using an electrically actuated uncoupling mechanism, and it is a further object to provide a simplified method of uncoupling a coupler head.

[0011] The invention is defined in the appending claims. Accordingly, the coupling is configured such that shutting off the supply of electric energy to the electrically driven uncoupling mechanism allows an uncoupling actuator of the uncoupling mechanism to return to the initial position from which it started out when it caused the disc (or "hook plate" or, more generally, "locking device") to rotate from its coupled position towards its uncoupled position. Thus, rather than releasing the uncoupling mechanism by electrically actuating the uncoupling mechanism in an opposite direction, it is the shutting off of power supply which causes the uncoupling mechanism to return to its initial position or at least allows the uncoupling mechanism to return to its initial position. In other words, no electric energy is needed to return the uncoupling mechanism to its initial or starting position. This simplifies the coupler head as well as the method of uncoupling the coupler head. It particularly also simplifies the controlling of the uncoupling process, since the return of the uncoupling mechanism to its initial or starting position may be automatic, not requiring any control signal.

[0012] More specifically, the coupler arrangement of the present disclosure comprises a coupler head with a locking device, such as a hook plate, which is rotatable about a main pin of the coupler head between a coupled position and an uncoupled position and which is configured to cooperate with a locking device of a corresponding second coupler head so as to couple the two coupler heads together when the locking device of each of the two coupler heads is in its respective coupled position. The coupler head further has a tension spring which provides a spring force configured to urge the locking device (in the following also referred to as "hook plate" for reason of simplification) towards its coupled position. In addition, the coupler arrangement comprises an electrically driven uncoupling device having an uncoupling actuator arranged to move, upon supply of electric energy to the uncoupling device, from a first actuator position (which is the initial or starting position) to a second actuator position, thereby causing the locking device (hook plate) to rotate from its coupled position to its uncoupled position against the spring force provided by the tension spring. Finally, as stated above, the arrangement is such that shutting off the supply of electric energy to the uncoupling device allows the uncoupling actuator to return to the first actuator position.

[0013] In the case of a dual position coupling with a latching mechanism which holds the locking device (hook plate) in the uncoupled position, the uncoupling actuator does not immediately return to its starting position before the latching mechanism is released, e.g. when the coupler head is approached by a corresponding second coupler head. However, in the case that the energy supply to the uncoupling device is shut off before the hook plate has reached the latching mechanism or in the case of a single position coupling without such a latching mechanism, the uncoupling actuator may return immediately and automatically to its starting position. Thus, at least in these cases the shutting off of the supply of electric energy to the uncoupling device does cause (not merely "allow") the uncoupling actuator to return to its starting position.

[0014] It is preferably the spring force provided by the tension spring which causes the uncoupling actuator to return to the first actuator position, i.e. the starting position, when the supply of electric energy to the uncoupling device is shut off. This keeps the structure of the coupling head simple. For instance, the uncoupling actuator or an element connected to the uncoupling actuator may be arranged to press against a cam surface of the locking device or hook plate when the uncoupling actuator is caused to rotate the locking device from its coupled position to its uncoupled position. Then, when the electric energy is shut off, the spring force of the tension spring urges the locking device or hook plate towards its coupled position and, in consequence, the locking device or hook plate urges the uncoupling actuator back towards the starting position.

[0015] However, instead of or in addition to the spring force provided by the tension spring, there may be provided a biasing element, separate from the tension spring, which urges the uncoupling actuator towards the starting position. For instance, such biasing element may act directly on the uncoupling actuator or on any element of the uncoupling device. Thus, the biasing element may form part of the uncoupling device.

[0016] Preferably, the arrangement is such that, when the locking device is in its uncoupled position, it is hindered from rotating about the main pin towards its coupled position while electric energy is supplied to the uncoupling device. This way, the locking device or hook plate may be held in its uncoupled position, in which case the coupler head is "not ready to couple". In other words, the coupler head is held in a buff state. However, this is only the case as long as electric energy is supplied to the uncoupling device. As soon as the energy supply is shut off, the uncoupling actuator of the uncoupling device is no longer hindered from returning to its starting position, thereby no longer blocking the locking device or hook plate from rotating towards its coupled position.

[0017] According to a preferred embodiment, the arrangement is such that a first part of the electric energy supplied to the uncoupling device is used to move the uncoupling actuator from the first actuator position to the second actuator position, whereas a second part of the electric energy supplied to the uncoupling device is used to hinder the uncoupling actuator from returning to the first actuator position. In particular, the second part of electric energy may be very little as compared to the first part. That is, moving the uncoupling actuator against (at least) the spring force provided by the tension spring of the coupler head towards its second position, i.e. the position in which the locking device or hook plate is in its uncoupled position, requires a relatively large amount of electric energy, which is the first part of the electric energy. Once the locking device has reached a desired position, i.e. its uncoupled position, only the second part of electric energy is needed to hinder the uncoupling actuator from returning to the starting position. Depending on the particular arrangement, this may be realized in a way which requires only very little energy.

[0018] According to a first approach, the arrangement is such that the second part of the electric energy is used to energize an electrically actuated valve so as to hold the electrically actuated valve in a first valve position in which the uncoupling actuator is hindered from returning to the first actuator position. Then, the shutting off of the supply of electric energy to the uncoupling device causes the electrically actuated valve to automatically switch into a second valve position in which the uncoupling actuator is no longer hindered from returning to the first actuator position. Switching valves between two positions does not require a large amount of electric energy. For instance, the valve may be held in an active position with very little energy against a moderate spring force and automatically return to a passive position due to the spring force when the valve is no longer energized. A preferred example of an electrically actuated valve is a solenoid valve, as solenoid valves are commonly used for such purpose and available in many different forms.

[0019] In particular, the uncoupling device may be an electro-hydraulic uncoupling device and comprise an electrically driven hydraulic pump for moving the uncoupling actuator from the first actuator position to the second actuator position, and the electrically actuated valve may be configured to close, when energized, a hydraulic line in the uncoupling device. For instance, when the uncoupling actuator of the uncoupling device is being moved or has been moved, hydraulically by means of the hydraulic pump, to the second position in which the locking device is in its uncoupled position, any flow of hydraulic fluid back through the hydraulic pump is usually blocked by the hydraulic pump. Thus, the uncoupling actuator cannot return to the starting position. However, when the energy supply is shut off, the electrically actuated valve in the hydraulic line is de-energized and, thus, automatically opens the hydraulic line so that the hydraulic fluid can bypass the hydraulic pump and flow back to a tank or reservoir.

[0020] According to a second approach, the arrangement is such that the second part of the electric energy is used to energize a clutch so as to hold the clutch in a first clutch mode in which the uncoupling actuator is hindered from returning to the first actuator position. Then, the shutting off of the supply of electric energy to the uncoupling device causes the clutch to switch into a second clutch mode in which the uncoupling actuator is no longer hindered from returning to the first actuator position. Again, switching a clutch between an active and a passive mode does not necessarily require much electric energy. For instance, the clutch may be held in an active position with very little energy against a moderate spring force and automatically return to a passive position due to the spring force when the clutch is no longer energized. For instance, the switch may be a solenoid switch.

[0021] In particular, the uncoupling device may comprise an electromechanical drive configured to move the uncoupling actuator from the first actuator position to the second actuator position. Mechanical parts of the electro-mechanical drive provide a certain inertia that needs to be overcome in order to return the uncoupling actuator to its starting position when the clutch is not energized, such as friction in a worm gear or in other parts of a transmission. Preferably, the arrangement is made such that a force required to move the uncoupling actuator, when the clutch is not energized, from the second actuator position to the first actuator position is less than 400 N. This force can be overcome by the spring force of the tension spring provided in the coupler head.

[0022] Preferably, the coupler head is a Scharfenberg-type coupler head and, therefore, comprises: a hook plate (as the locking device) which is rotatable about the main pin of the coupler head between the coupled position and the uncoupled position and which comprises a coupling link pin on a first side relative to the main pin and a hook plate recess on a second side relative to the main pin opposite the first side, and a coupling link having a first end connected to the coupling link pin of the hook plate so as to be rotatable about the coupling link pin and a free second end to be received in the hook plate recess of a corresponding opposite coupler head.

[0023] More preferably, the coupler head further comprises a latching mechanism which is configured to hold the hook plate in the uncoupled position and which is automatically released mechanically when the coupler head is approached by a corresponding second coupler head.

[0024] As already mentioned before, the uncoupling actuator or an element connected to the uncoupling actuator may be arranged to press against a cam surface of the locking device or hook plate when the uncoupling actuator is caused to rotate the locking device or hook plate from its coupled position to its uncoupled position. Preferably, the coupler head comprises a coupler head housing in which at least the locking device and the tension spring are accommodated. A drive of the uncoupling device may be arranged on an outside of the coupler head housing with the uncoupling actuator of the uncoupling device extending through a wall of the coupler head housing into the coupler head housing. By this arrangement, it is easy to attach the uncoupling device to already existing coupler heads.

[0025] More preferably, the coupler head housing has a forward end arranged to contact the forward end of a corresponding second coupler head when the two coupler heads are coupled together and further has a rearward end, wherein the main pin is arranged between the forward end and the rearward end, and the uncoupling actuator extends through a wall of the coupler head housing rearward of the main pin. By this arrangement, the uncoupling device may be arranged on a rear side of the coupler head, thereby protecting it from being damaged.

[0026] Another, even better, way of protecting the uncoupling device from damage consists in mounting the uncoupling device to a car of the rail vehicle. That is, a coupling arrangement may comprise at least one of a dampening device and shock-absorbing device between the coupler head and the car. By mounting the uncoupling device on the car rather than on the coupler head, shocks acting on the coupler head, e.g. during a coupling process, will not affect the uncoupling device or its components.

[0027] In this case, the coupling arrangement preferably comprises a linking mechanism which links the uncoupling actuator of the uncoupling device to the coupler head so that movement of the uncoupling actuator from the first actuator position to the second actuator position is transferred to the coupler head so that the locking device or hook plate is caused to rotate from its coupled position to its uncoupled position. In preferred embodiments, the linking mechanism comprises a pull cable or a hydraulic line. Both variants allow the transfer of mechanic or hydraulic energy over long distances, do not require much space and are easy to adapt to different requirements.

[0028] For instance, the coupler head may comprise a coupler head housing with the main pin extending through a wall of the coupler head housing, wherein the linking mechanism is connected to the main pin outside of the coupler head housing. For instance, the pull cable may be attached to the main pin eccentrically from the rotating axis of the main pin so as to turn the main pin about the rotating axis by pulling the pull wire. Alternatively, a hydraulically actuated piston may act in a similar way eccentrically on the main pin. Thus, in this case it is not necessary to guide any element of the uncoupling device through a wall of the coupler head housing.

[0029] In addition, as a safety measure, a handle may be provided for manually rotating the locking device from its coupled position to its uncoupled position.

[0030] The coupler arrangement is particularly suitable for freight wagons of multi-car rail vehicles, in particular if the uncoupling device is mounted on the freight wagon, as discussed above. In addition, a battery for providing electric energy to the uncoupling device may be attached to the freight wagon. This way, weight acting on the coupler head may be kept limited.

[0031] The present disclosure further relates to a method of uncoupling a coupler head of a coupler arrangement as set out above, wherein the method comprises the steps of: providing a digital uncoupling signal, upon the provision of the uncoupling signal, supplying electric energy to the uncoupling device so as to move the uncoupling actuator of the uncoupling device from the first actuator position to the second actuator position, thereby causing the locking device of the coupler head to rotate from its coupled position towards its uncoupled position against the spring force provided by the tension spring of the coupler head, and shutting off the supply of electric energy to the uncoupling device, thereby allowing the uncoupling actuator to return to the first actuator position. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The foregoing summary, as well as the following detailed description of preferred embodiments, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, reference is made to the drawings. The scope of the disclosure is not limited, however, to the specific embodiments disclosed in the drawings. In the drawings: Fig. 1 is a cross-sectional plan view of a coupler head in a coupled position, Fig. 2 is a cross-sectional plan view of two coupler heads as shown in Fig. 1 coupled together, Fig. 3 is a cross-sectional plan view of the coupler head of Fig. 1 in an uncoupled position, Fig. 4 is a cross-sectional plan view of two coupler heads as shown in Fig. 1 in a buff state, Fig. 5 is a schematic drawing of an electromechanical uncoupling device, Fig. 6 is a schematic drawing of an electro-hydraulic uncoupling device, Fig. 7 is a side view of a coupler arrangement with the uncoupling device attached to a car of a rail vehicle, Fig. 8 is a bottom plan view of the coupler head of the coupler arrangement shown in Fig. 7, Fig. 9 shows a coupler arrangement with an unlocking handle in a coupled state, Fig. 10 shows the coupler arrangement of Fig. 9 in a buff state, and Fig. 11 shows details of the coupler arrangement of Figs. 9 and 10. DETAILED DESCRIPTION

[0033] Fig. 1 is a cross-sectional plan view of a coupler head 1 in a coupled position. The coupler head 1 has a coupler face 2 at its front end and has a rear end to which a coupler rod is attached for connecting the coupler head 1 to a car of a rail vehicle. The coupler rod usually includes one or preferably both of a dampening device and a shock-absorbing device, as is usual in central buffer couplings. Thus, the dampening device and shock-absorbing device is arranged between the coupler head 1 and the car of the rail vehicle.

[0034] The coupler head 1 further has a male cone 4, usually referred to simply as cone, and a female cone 5, usually referred to as cup, receiving the cone of a second coupler head 1 in order to align the coupler heads when they mate with their respective coupler faces 2.

[0035] Inside the coupler head housing 6, there is contained a locking device 7 in the form of a hook plate which can rotate about a main pin 8. A coupling link 9 or hook is pivotably attached with a first end 9A to the hook plate 7 and has a second end 9B which is configured to engage a hook plate recess 7A or notch of the hook plate 7. A tension spring 10 connects the hook plate 7 to the coupler housing 6 so as to urge the hook plate 7 into the position shown in Fig. 1, which shows a coupled position of the coupler head 1.

[0036] There is further provided a latching mechanism 11 which comprises a trigger 12 or stamp which is urged into an extended position by a trigger spring 13. The latching mechanism 11 comprises further components which are partly shown in Fig. 1 and well known to the skilled person in the art so that they will not be described here in further detail. In any case, the latching mechanism 11 usually prevents the hook plate 7 from returning, after an uncoupling process and biased by the spring force of the tension spring 10, into the coupled position shown in Fig. 1. Instead, when the latching mechanism 11 is effective, different to what is shown in Fig. 1, the hook plate 7 is held - against the spring force of the tension spring 10 - in a position in which the hook plate recess 7A is open towards the front side of the coupler head 1 so that the second end 9B of a coupling link 9 of a second coupler head can immediately engage with the hook plate recess 7A during a coupling process. But also in the situation shown in Fig. 1, where the latching mechanism 11 is not effective, can two coupler heads 1 couple together. In this case, the free second end 9B of the coupling link 9 of both coupler heads 1 contact a surface of the hook plate 7 of the respective other coupler head 1 when the coupler heads 1 are being moved against each other, thereby rotating the hook plates 7 about their main pin 8 until the second end 9B of the coupling links 9 engage with the hook plate recess 7A of the respective other hook plate 7. In this moment, the hook plates 7 are no longer blocked from rotating into the opposite direction by the spring force of the tension spring 10, thereby coupling the two coupler heads 1 together. The coupled state of two coupler heads 1 is shown in Fig. 2. As can be seen from Fig. 2, in this state the trigger 12 of the coupler head 1 is compressed against the trigger spring 13 by the cone 4 of the respective other coupler head 1

[0037] In order to uncouple the coupler heads 1 again, their locking devices 7 or hook plates need to be unlocked by rotating the hook plates 7 about their main pins 8 against the spring force of the tension springs 10 until the second ends 9B of the coupling links 9 can disengage from the hook plate recess 7A of the respective other hook plate 7. For this purpose, an uncoupling device 14 is attached to the coupler head housing 6 at a position between the main pin 8 and the reward end 3 of the coupler head 1. The uncoupling device 14 comprises an uncoupling actuator 15, here in the form of a piston, which extends through a wall of the coupler head housing 6 into the coupler head housing 6. There, the uncoupling actuator 15 contacts, with a front end 15A thereof, a cam surface 7B of the hook plate 7.

[0038] The uncoupling device 14 further comprises an electric motor 16 which drives the uncoupling actuator 15 by means of transmission gears 17. The uncoupling actuator 15 or piston is a linear actuator, meaning that the motion of the electric motor 16 is transformed into a linear motion of the piston 15. The uncoupling actuator 15, electric motor 16 and transmission gears 17 are contained in a housing 18 which is attached to the outside of the coupler head housing 6.

[0039] Although each of the two coupler heads 1 is equipped with an uncoupling device 14 as described before, it is sufficient for an uncoupling process to actuate only one of the pistons 15. More specifically, upon the advancement of the piston 15 from the position shown in Fig. 2 into the position shown in Fig. 3, the front end 15A of the piston 15 urges the hook plate 7 to rotate about the main pin 8, thereby sliding along the cam surface 7B of the hook plate 7. The position of the hook plate 7 of the coupler head 1 as shown in Fig. 3 is the uncoupled position, in which the latching mechanism 11 is active so as to prevent the hook plate 7 from returning into the coupled position shown in Fig. 1

[0040] Whether or not the hook plate 7 is in a ready-to-couple position or in a buff position, in which it is not ready to couple, depends on whether the uncoupling actuator 15 is allowed to return to its initial position shown in Fig. 1. That is, as long as the uncoupling actuator 15 is actuated by means of the electric motor 16 so as to extend into the position as shown in Fig. 3, the spring force of the tension spring 10 cannot cause the hook plate 7 to rotate about the main pin 8 during a coupling process. This is further shown in Fig. 4 where two coupler heads 1 are in tight contact with their coupler faces 2 and, although the trigger 12 of the latching mechanism 11 is compressed against the trigger spring 13, thereby releasing the hook plate 7, the hook plate 7 is nevertheless held in its uncoupled position by the extended uncoupling actuator 15. Accordingly, the coupler 1 is in the buff state.

[0041] The hook plate 7 can return to its coupled position only when the uncoupling actuator 15 is no longer energized by means of the electric motor 16. That is, the arrangement is such that the uncoupling actuator 15 is free to return to its initial position when no energy is supplied to the uncoupling device 14. In particular, such return of the uncoupling actuator 15 towards its initial position is automatic. Since in the embodiment shown in Fig. 4 the uncoupling actuator 15 does not itself contain a spring or other resilient means for returning the uncoupling actuator 15, it is solely the spring force of the tension spring (10) which causes the uncoupling actuator 15 to be pushed back towards its initial position by means of the cam surface 7B of the hook plate 7.

[0042] While Figs. 1 through 4 show an uncoupling device 14 with an electromechanical motor 16, other electric motors may likewise be employed, in particular an electro-hydraulic motor.

[0043] In any case, it is the shutting off of the supply of energy to the uncoupling device 14 which allows the uncoupling actuator 15 to return to its initial position, thereby allowing the hook plate 7 to return to its coupled position. Accordingly, another advantage of this arrangement is that the coupler heads of two cars of a rail vehicle can couple safely even in the case of a power failure. Notably, the return of the hook plate 7 towards its coupled position as shown in Fig. 1 also occurs in the case of a power failure during an uncoupling process, i.e. before the uncoupling actuator 15 has reached its fully extended position in which the hook plate 7 is held in the ready-to-couple position by the latching mechanism 11.

[0044] In a preferred embodiment, the electric energy supplied to the uncoupling device 15 is composed of two parts, namely a first part which is used to move the uncoupling actuator 15 from the initial actuator position shown in Fig. 1 to the extended position shown in Fig. 3 and a second part which is used to prevent the uncoupling actuator 15 from returning to its initial position. Thus, once the uncoupling actuator 15 has reached its fully extended position, only the second part of the electric energy needs to be supplied to the uncoupling device 1, which second part may be substantially lower than the first part. This will be explained in further detail in relation to the schematic drawings of an electromechanical uncoupling device as shown in Fig. 5 and an electro-hydraulic uncoupling device as shown in Fig. 6.

[0045] Fig. 5 shows an electromechanical uncoupling device 14 with a housing 18 in which an electric motor 16 drives a linear actuator comprising an uncoupling actuator 15 in the form of a piston that extends from the housing 18 into a coupler head housing 6 when the coupling device 14 is attached to the coupler head 1. In this embodiment, unlike the embodiment of Figs. 1 to 4, a return spring 19 is provided in the uncoupling device 14 so as to urge the uncoupling device 15 towards its initial position (towards the right in the embodiment shown in Fig. 5). The return spring 19 supports the spring force of the tension spring 10. An additional effect is that the uncoupling actuator 15 may return to its initial position upon shutting-off the electric energy supplied to the uncoupling device 14 even in the case that the hook plate 7 is still held in its uncoupled position by the latching mechanism 11 (see Fig. 3).

[0046] In the embodiment shown in Fig. 5, the transmission gears 17 comprise three gear wheels 17A, 17B, 17C, namely a drive wheel 17A connected to the electric motor 16, a driven wheel 17B connected to the linear actuator 15 or piston, and a transmission wheel 17C connecting the drive wheel 17A with the driven wheel 17B. The transmission wheel 17C makes part of a clutch 20. That is, the transmission wheel 17C can be moved in and out of engagement with the driven wheel 17B. More specifically, the transmission wheel 17C engages the driven wheel 17B only when an electric actuator 20A is energized. In the embodiment shown, energizing the electric actuator 20A has the effect that the transmission wheel 17C moves towards the left, as indicated by the arrow. A return spring 20B urges the transmission wheel 17C out of engagement with the driven wheel 17B as soon as the electric actuator 20A is de-energized, i.e. as soon as the supply of electric energy is shut off. As a result, when the driven wheel 17B is no longer connected to the drive wheel 17A by means of the transmission wheel 17C, the piston 15 can wind back towards and up to its initial position (towards the right in the embodiment shown in Fig. 5) due to the spring force of the return spring 19 and / or due to the spring force of the tension spring 10 of the coupler head 1. Thus, by simply shutting off the energy supplied to the uncoupling device 14, a buff state of the coupler head 1 can be released so that the coupler head 1 is ready to couple.

[0047] Importantly, a first part of energy which is needed to advance the piston 15 against the spring forces of the return spring 19 and tension spring 10 out of the housing 18, and which is relatively large, needs to be provided only until the piston 15 has reached its fully extended position. The piston is prevented from returning to its initial position as long as the second part of energy is provided to the electric actuator 20A of the clutch 20, which second part of energy is relatively little. When also the second part of energy is no longer supplied to the uncoupling device 14, i.e. when no electric energy is supplied to the uncoupling device 14 at all, the clutch 20 automatically releases due to the spring force of the return spring 20B, because in this situation the driven wheel 17B can freewheel. In other words, only very little energy is needed to hold the coupler head in a buff state.

[0048] The force needed to overcome the friction in the linear actuator in order to wind the piston back towards its initial position is relatively little and should not exceed 400 N, preferably not even 100 N, so that it can be overcome by the return spring 19 and / or tension spring 10 of the coupler head 1.

[0049] Fig. 6 discloses a very similar device 14, which includes an electro-hydraulic motor. Here, the uncoupling actuator 15 or piston can move back and forth in hydraulic chamber 21 with the front end 15A of the piston 15 extending from the hydraulic chamber 21 into the coupler head housing 6 when the uncoupling device 14 is attached to the coupler head 1. Pumping hydraulic fluid by means of a hydraulic pump 22 causes the piston 15 to move against the spring force of the return spring 19 so that the front end 15A of the piston 15 extends from the hydraulic chamber 21. Backflow of the hydraulic fluid from the hydraulic chamber 21 towards a reservoir 23 is prevented by the hydraulic pump 22, on the one hand, and an electrically actuated valve 24, on the other hand, which valve is provided in a bypass line 25 bypassing the hydraulic pump 22. Like the electrically actuated switch or clutch 20 in the embodiment of Fig. 5, the electrically actuated valve 24 in the embodiment of Fig. 6 includes an electric actuator 24A and a return spring 24B. Back flow of the hydraulic fluid from the hydraulic chamber 21 into the reservoir 23 and, thus, release of the uncoupling actuator 15 occurs as soon as the electric actuator 24A is no longer energized so that the electrically actuated valve 24 automatically opens due to the spring force of the return spring 24B. Again, the force and, thus, the electric energy needed to close the electrically actuated valve 24 in order to hold the uncoupling actuator 15 in its extended position is very little as compared to the other part of energy supplied to the uncoupling device 14 that is needed for driving the electrically driven hydraulic pump 22 when the uncoupling actuator 15 moves from its initial position towards its extended position. As a result, very little energy is needed to hold the coupler head 1 in the buff state, whereas the energy supply to the uncoupling device 14 needs simply be shut off in order to release the uncoupling actuator 15 and allow the hook plate 7 of the coupler head 1 to return to its coupled position.

[0050] Both, the electrically actuated switch or clutch 20 described above in relation to the embodiment shown in Fig. 5 and the electrically actuated valve 24 as described above in relation to the embodiment shown in Fig. 6 may comprise a solenoid as the electric actuators 20A and 24A, respectively.

[0051] Figs. 7 and 8 show a different embodiment in which the uncoupling device 14 is mounted to a car 100 of the rail vehicle, more specifically to the undercarriage thereof. A battery 28 providing energy to the uncoupling device 14 is also provided on the car 100. As can be seen, the coupler head 1 is connected to the car 100 by means of a coupler rod 26 which may contain one or both of a dampening device and shock-absorbing device. By arranging the uncoupling device 14 on the car 100, forces acting on the coupler head 1 are largely absorbed by the coupler rod 26 and by the dampening device and shock-absorbing device incorporated therein.

[0052] In the embodiment shown in Figs. 7 and 8, the uncoupling device 14 includes an electromechanical drive, and the uncoupling actuator 15 extending from the housing 18 of the uncoupling device 14 is connected to the coupler head 1 by means of a linking mechanism 27. The linking mechanism 27, in this embodiment, comprises a Bowden cable which includes a pull cable 27A, wherein the pull cable 27A is eccentrically connected to an end of the main pin 8 which extends through the coupler head housing 6 of the coupler head 1, as is shown in Fig. 8.

[0053] Instead of an electro-mechanical drive, the uncoupling device 14 may include an electro-hydraulic drive. Furthermore, instead of a Bowden cable 27 and / or pull cable 27A, a hydraulic line may connect the uncoupling device 14 with a hydraulic actuator on the coupler head 1, which hydraulic actuator acts eccentrically on the main pin 8, similar to the arrangement in Fig. 8.

[0054] Figs. 9 to 11 show a further embodiment in which the uncoupling device 14 is arranged on the car 100. Again, the uncoupling device 14 includes an electromechanical drive with the uncoupling actuator 15 extending from the housing 18 of the uncoupling device 14. In addition, two handles 103' and 103" are provided on opposite sides of the car 100. The uncoupling actuator 15 and the handles 103' and 103" each cooperate with the same mechanical mechanism, which mechanism transfers the movement of the handles 103' and 103" and the movement of the uncoupling actuator 15 in the same way to the coupler head 1. The handles 103' and 103" are provided to manually rotate the hook plate 7 (not shown) from its coupled position to its uncoupled position. Fig. 9 shows the two handles 103' and 103" in their first position, corresponding to the coupled state of the coupler head 1, and Fig. 10 shows the handles 103' and 103" in a position which corresponds to the buff state of the coupler head 1. Here, an extension of the handle 103' in the form of a connector rod 120 translates a pivoting movement of the handle 103' about an axis of rotation A into a corresponding rotation of a linking rod 114 about an axis of rotation A' that is parallel to the axis of rotation A so as to move the hook plate 7 from the coupled position to the uncoupled position. The connector rod 120 further translates a tilting movement of the handles 103', 103" into a corresponding tilting movement of a ledge 121, to which a first rod section 114A' is attached with one of its ends, while the second handle 103" is connected to the rod 114 and a second rod section 114A" in the same manner as the first handle 103'. As a result, rotational movement of either one of the two handles 103', 103" about the axis of rotation A and / or tilting movement of either one of the first and second handles 103', 103" will result in a corresponding rotational and / or tilting movement of the respective other handle. By tilting the handles 103' and 103", the handles can be moved behind a holder 123, thereby holding the handles in the uncoupled position, which is then - in fact - a not-ready-to-couple-position or, in other words, a buff position

[0055] Fig. 11 shows in more detail how the linking rod 14 and the rod sections 114A' and 114A" cooperate with a rotatable element 118 and a connector 119. In particular, the connector 119 may have the form of a cam plate or eccentric plate on which a pull cable 27A may wind up when the handles 103' and 103" are moved from their first position (coupled position) to their second position (uncoupled position). The uncoupling device 14 acts on the connector rod 120 in the same way as if the handle 103' or 103" was moved from the first, coupled position to the second, uncoupled position.

[0056] Preferred aspects of the present disclosure are specified in the following paragraphs, whereas the scope of protection of the present invention is defined by the appended claims. 1. A coupler arrangement for a rail vehicle, the coupler arrangement comprising a coupler head (1) with a locking device (7) which is rotatable about a main pin (8) of the coupler head (1) between a coupled position and an uncoupled position and which is configured to cooperate with a locking device (7) of a corresponding second coupler head (1) so as to couple the two coupler heads (1) together when the locking device (7) of each of the two coupler heads (1) is in its respective coupled position, and a tension spring (10) providing a spring force configured to urge the locking device (7) towards its coupled position, wherein the coupler arrangement further comprises an electrically driven uncoupling device (14) having an uncoupling actuator (15) arranged to move, upon supply of electric energy to the uncoupling device (14), from a first actuator position to a second actuator position, thereby causing the locking device (7) to rotate from its coupled position to its uncoupled position against the spring force provided by the tension spring (10), wherein the arrangement is such that shutting off the supply of electric energy to the uncoupling device (14) allows the uncoupling actuator (15) to return to the first actuator position. 2. The coupler arrangement of paragraph 1, wherein the arrangement is such that the shutting off of the supply of electric energy to the uncoupling device (14) causes the uncoupling actuator (15) to return to the first actuator position. 3. The coupler arrangement of paragraph 1 or 2, wherein the arrangement is such that, when the supply of electric energy to the uncoupling device (14) has been shut off, the spring force provided by the tension spring (10) causes the uncoupling actuator (15) to return to the first actuator position. 4. The coupler arrangement of any one of paragraphs 1 to 3, wherein a biasing element (19) is provided, separate from the tension spring (10), so as to urge the uncoupling actuator (15) towards the first actuator position. 5. The coupler arrangement of any one of paragraphs 1 to 4, wherein the arrangement is such that, when the locking device (7) is in its uncoupled position, the locking device (7) is hindered from rotating about the main pin (8) towards its coupled position while electric energy is supplied to the uncoupling device (14). 6. The coupler arrangement of any one of paragraphs 1 to 5, wherein the arrangement is such that a first part of the electric energy supplied to the uncoupling device (14) is used to move the uncoupling actuator (15) from the first actuator position to the second actuator position and a second part of the electric energy supplied to the uncoupling device (14) is used to hinder the uncoupling actuator (15) from returning to the first actuator position. 7. The coupler arrangement of paragraph 6, wherein the arrangement is such that the second part of the electric energy is used to energize an electrically actuated valve (24) so as to hold the electrically actuated valve (24) in a first valve position in which the uncoupling actuator (15) is hindered from returning to the first actuator position, wherein the shutting off of the supply of electric energy to the uncoupling device (14) causes the electrically actuated valve (24) to automatically switch into a second valve position in which the uncoupling actuator (15) is no longer hindered from returning to the first actuator position. 8. The coupler arrangement of paragraph 7, wherein the electrically actuated valve (24) is a solenoid valve. 9. The coupler arrangement of paragraph 7 or 8, wherein the uncoupling device (14) comprises an electrically driven hydraulic pump (22) configured to move the uncoupling actuator (15) from the first actuator position to the second actuator position and wherein the electrically actuated valve (24) is configured, when energized, to close a hydraulic line (25) of the uncoupling device (14). 10. The coupler arrangement of paragraph 6, wherein the arrangement is such that the second part of the electric energy is used to energize a clutch (20) so as to hold the clutch (20) in a first clutch mode in which the uncoupling actuator (15) is hindered from returning to the first actuator position, wherein the shutting off of the supply of electric energy to the uncoupling device (14) causes the clutch (20) to switch into a second clutch mode in which the uncoupling actuator (15) is no longer hindered from returning to the first actuator position. 11. The coupler arrangement of paragraph 10, wherein the uncoupling device (14) comprises an electromechanical drive configured to move the uncoupling actuator (15) from the first actuator position to the second actuator position. 12. The coupler arrangement according to paragraph 10 or 11, wherein a force required to move the uncoupling actuator (15), when the clutch (20) is not energized, from the second actuator position to the first actuator position is less than 400 N, preferably less than 100 N. 13. The coupler arrangement of any one of paragraphs 1 to 12, wherein the locking device (7) comprises: a hook plate which is rotatable about the main pin (8) of the coupler head (1) between the coupled position and the uncoupled position and which comprises a coupling link pin on a first side relative to the main pin (8) and a hook plate recess (7A) on a second side relative to the main pin (8) opposite the first side, and a coupling link (9) having a first end (9A) connected to the coupling link pin of the hook plate so as to be rotatable about the coupling link pin and a free second end (9B) to be received in the hook plate recess (7A) of a corresponding opposite coupler head (1). 14. The coupler arrangement of paragraph 13, wherein the coupler head (1) comprises a latching mechanism (11) which is configured to hold the hook plate in the uncoupled position and which is automatically released mechanically when the coupler head (1) is approached by a corresponding second coupler head (1). 15. The coupler arrangement of paragraph 13 or 14, wherein the uncoupling actuator (15) or an element connected to the uncoupling actuator (15) is arranged to press against a cam surface (7B) of the hook plate when the uncoupling actuator (15) is caused to rotate the locking device (7) from its coupled position to its uncoupled position. 16. The coupler arrangement of any one of paragraphs 1 to 15, wherein the coupler head (1) comprises a coupler head housing (6) in which at least the locking device (7) and the tension spring (10) are accommodated, wherein a drive of the uncoupling device (14) is arranged on an outside of the coupler head housing (6) and the uncoupling actuator (15) of the uncoupling device (14) extends through a wall of the coupler head housing (6) into the coupler head housing (6). 17. The coupler arrangement of paragraph 16, wherein the coupler head housing (6) has a forward end arranged to contact the forward end of a corresponding second coupler head (1) when the two coupler heads (1) are coupled together and further has a rearward end (3), wherein the main pin (8) is arranged between the forward end and the rearward end (3) and the uncoupling actuator (15) extends through a wall of the coupler head housing (6) rearward of the main pin (8). 18. The coupler arrangement of any one of paragraph 1 to 15, further comprising at least one of a dampening device and shock-absorbing device, wherein the coupler head (1) is configured to be connected to a car (100) of the rail vehicle with the at least one of a dampening device and shock-absorbing device arranged between the coupler head (1) and the car (100), wherein the uncoupling device (14) is configured to be mounted on the car (100). 19. The coupler arrangement of paragraph 18, comprising a linking mechanism (27) which links the uncoupling actuator (15) of the uncoupling device (14) to the coupler head (1) so that movement of the uncoupling actuator (15) from the first actuator position to the second actuator position is transferred to the coupler head (1) so as to cause the locking device (7) to rotate from its coupled position to its uncoupled position. 20. The coupler arrangement of paragraph 19, wherein the linking mechanism (27) comprises a pull cable (27A). 21. The coupler arrangement of paragraph 19, wherein the linking mechanism (27) comprises a hydraulic line. 22. The coupler arrangement of any one of paragraphs 19 to 21, wherein the coupler head (1) comprises a coupler head housing (6) with the main pin (8) extending through a wall of the coupler head housing (6), and wherein the linking mechanism (27) is connected to the main pin (8) outside of the coupler head housing (6). 23. The coupler arrangement of any one of paragraphs 1 to 22, comprising a handle (30) configured for manually rotating the locking device (7) to its uncoupled position. 24. A freight wagon of a rail vehicle, comprising a coupler arrangement of any one of paragraphs 18 to 23, wherein the uncoupling device (14) is mounted on the freight wagon. 25. The freight wagon of paragraph 24, further comprising a battery (28) attached to the freight wagon. 26. A method of uncoupling a coupler head (1) of a coupler arrangement which comprises: the coupler head (1) with a locking device (7) which is rotatable about a main pin (8) of the coupler head (1) between a coupled position and an uncoupled position and which is configured to cooperate with a locking device (7) of a corresponding second coupler head (1) so as to couple the two coupler heads (1) together when the locking device (7) of each of the two coupler heads (1) is in its respective coupled position, and a tension spring (10) providing a spring force configured to urge the locking device (7) towards its coupled position, and an electrically driven uncoupling device (14) having an uncoupling actuator (15) arranged to move, upon supply of electric energy to the uncoupling device (14), from a first actuator position to a second actuator position, thereby causing the locking device (7) to rotate from its coupled position to its uncoupled position against the spring force provided by the tension spring (10), wherein the method comprises the steps of: providing a digital uncoupling signal, upon the provision of the uncoupling signal, supplying electric energy to the uncoupling device (14) so as to move the uncoupling actuator (15) of the uncoupling device (14) from the first actuator position to the second actuator position, thereby causing the locking device (7) of the coupler head (1) to rotate from its coupled position towards its uncoupled position against the spring force provided by the tension spring (10) of the coupler head (1), and shutting off the supply of electric energy to the uncoupling device (14), thereby allowing the uncoupling actuator (15) to return to the first actuator position. 27. The method of paragraph 26, wherein the step of shutting off the supply of electric energy to the uncoupling device (14) causes the uncoupling actuator (15) to return to the first actuator position. 28. The method of paragraph 27, wherein the step of shutting off the supply of electric energy to the uncoupling device (14) causes the uncoupling actuator (15) to return to the first actuator position due to the spring force provided by the tension spring (10). 29. The method of paragraph 27 or 28, wherein the step of shutting off the supply of electric energy to the uncoupling device (14) causes the uncoupling actuator (15) to return to the first actuator position due to a biasing force generated by a biasing element (19) which is provided separate from the tension spring (10). 30. The method of any one of paragraphs 26 to 29, comprising the step of supplying, when the locking device (7) is in its uncoupled position, electric energy to the uncoupling device (14) so as to hinder the locking device (7) from rotating about the main pin (8) towards its coupled position. 31. The method of any one of paragraphs 26 to 30, comprising the steps of using a first part of the electric energy to the uncoupling device (14) so as to move the uncoupling actuator (15) from the first actuator position to the second actuator position and using a second part of the electric energy supplied to the uncoupling device (14) so as to hinder the uncoupling actuator (15) from returning to the first actuator position. 32. The method of paragraph 31, comprising the step of using the second part of the electric energy to energize an electrically actuated valve (24) so as to hold the electrically actuated valve (24) in a first valve position in which the uncoupling actuator (15) is hindered from returning to the first actuator position, wherein the step of shutting off the supply of electric energy to the uncoupling device (14) causes the electrically actuated valve (24) to automatically switch into a second valve position in which the uncoupling actuator (15) is no longer hindered from returning to the first actuator position. 33. The method of paragraph 32, wherein the electrically actuated valve (24) is a solenoid valve. 34. The method of paragraph 32 or 33, wherein the uncoupling device (14) comprises an electrically driven hydraulic pump (22) configured to move the uncoupling actuator (15) from the first actuator position to the second actuator position and wherein the step of energizing the electrically actuated valve (24) so as to hold the electrically actuated valve (24) in the first valve position in which the uncoupling actuator (15) is hindered from returning to the first actuator position comprises the step of closing a hydraulic line (25) of the uncoupling device (14). 35. The method of paragraph 34, comprising the step of using the second part of the electric energy to energize a clutch (20) so as to hold the clutch (20) in a first clutch mode in which the uncoupling actuator (15) is hindered from returning to the first actuator position, wherein the step of shutting off the supply of electric energy to the uncoupling device (14) causes the clutch (20) to switch into a second clutch mode in which the uncoupling actuator (15) is no longer hindered from returning to the first actuator position. 36. The method of paragraph 35, wherein the uncoupling device (14) comprises an electromechanical drive and wherein the method comprises the step of using the electromechanical drive to move the uncoupling actuator (15) from the first actuator position to the second actuator position. 37. The method according to paragraph 35 or 36, wherein a force required to move the uncoupling actuator (15), when the clutch (20) is not energized, from the second actuator position to the first actuator position is less than 400 N, preferably less than 100 N. 38. The method of any one of paragraphs 26 to 37, wherein the locking device (7) comprises: a hook plate which is rotatable about the main pin (8) of the coupler head (1) between the coupled position and the uncoupled position and which comprises a coupling link pin on a first side relative to the main pin (8) and a hook plate recess (7A) on a second side relative to the main pin (8) opposite the first side, and a coupling link (9) having a first end (9A) connected to the coupling link pin of the hook plate so as to be rotatable about the coupling link pin and a free second end (9B) to be received in the hook plate recess (7A) of a corresponding opposite coupler head (1). 39. The method of paragraph 38, wherein the coupler head (1) comprises a latching mechanism (11) which is configured to hold the hook plate in the uncoupled position and which is automatically released mechanically when the coupler head (1) is approached by a corresponding second coupler head (1). 40. The method of paragraph 37 or 38, wherein the step of supplying electric energy to the uncoupling device (14) so as to move the uncoupling actuator (15) from the first actuator position to the second actuator position, thereby causing the locking device (7) of the coupler head (1) to rotate from its coupled position towards its uncoupled position, comprises pressing the uncoupling actuator (15) or an element connected to the uncoupling actuator (15) against a cam surface (7B) of the hook plate. 41. The method of any one of paragraphs 26 to 40, wherein the coupler head (1) comprises a coupler head housing (6) in which at least the locking device (7) and the tension spring (10) are accommodated, wherein a drive of the uncoupling device (14) is arranged on an outside of the coupler head housing (6) and the uncoupling actuator (15) of the uncoupling device (14) extends through a wall of the coupler head housing (6) into the coupler head housing (6). 42. The method of paragraph 41, wherein the coupler head housing (6) has a forward end arranged to contact the forward end of a corresponding second coupler head (1) when the two coupler heads (1) are coupled together and further has a rearward end (3), wherein the main pin (8) is arranged between the forward end and the rearward end (3) and the uncoupling actuator (15) extends through a wall of the coupler head housing (6) rearward of the main pin (8). 43. The method of any one of paragraph 26 to 40, wherein the coupler head (1) is connected to a car (100) of the rail vehicle with at least one of a dampening device and shock-absorbing device arranged between the coupler head (1) and the car (100), and wherein the uncoupling device (14) is mounted on the car (100). 44. The method of paragraph 43, wherein a linking mechanism (27) links the uncoupling actuator (15) of the uncoupling device (14) to the coupler head (1), wherein the method comprises the step of transferring, by means of the linking mechanism (27), movement of the uncoupling actuator (15) to the coupler head (1) so as to cause the locking device (7) to rotate from its coupled position to its uncoupled position. 45. The method of paragraph 44, wherein the linking mechanism (27) comprises a pull cable (27A). 46. The method of paragraph 44, wherein the linking mechanism (27) comprises a hydraulic line. 47. The method of any one of paragraphs 44 to 46, wherein the coupler head (1) comprises a coupler head housing (6) with the main pin (8) extending through a wall of the coupler head housing (6), and wherein the linking mechanism (27) is connected to the main pin (8) outside of the coupler head housing (6). 48. The method of any one of paragraphs 26 to 47, comprising the step of using a handle (30) for manually rotating the locking device (7) to its uncoupled position.

Claims

1. A coupler arrangement for a rail vehicle, the coupler arrangement comprising a coupler head (1) with - a locking device (7) which is rotatable about a main pin (8) of the coupler head (1) between a coupled position and an uncoupled position and which is configured to cooperate with a locking device (7) of a corresponding second coupler head (1) so as to couple the two coupler heads (1) together when the locking device (7) of each of the two coupler heads (1) is in its respective coupled position, and - a tension spring (10) providing a spring force configured to urge the locking device (7) towards its coupled position, wherein the coupler arrangement further comprises an electrically driven uncoupling device (14) having an uncoupling actuator (15) arranged to move, upon supply of electric energy to the uncoupling device (14), from a first actuator position to a second actuator position, thereby causing the locking device (7) to rotate from its coupled position to its uncoupled position against the spring force provided by the tension spring (10), wherein the arrangement is such that shutting off the supply of electric energy to the uncoupling device (14) allows the uncoupling actuator (15) to return to the first actuator position.

2. The coupler arrangement of claim 1, wherein the arrangement is such that the shutting off of the supply of electric energy to the uncoupling device (14) causes the uncoupling actuator (15) to return to the first actuator position.

3. The coupler arrangement of claim 1 or 2, wherein the arrangement is such that, when the supply of electric energy to the uncoupling device (14) has been shut off, the spring force provided by the tension spring (10) causes the uncoupling actuator (15) to return to the first actuator position.

4. The coupler arrangement of any one of claims 1 to 3, wherein a biasing element (19) is provided, separate from the tension spring (10), so as to urge the uncoupling actuator (15) towards the first actuator position.

5. The coupler arrangement of any one of claims 1 to 4, wherein the arrangement is such that, when the locking device (7) is in its uncoupled position, the locking device (7) is hindered from rotating about the main pin (8) towards its coupled position while electric energy is supplied to the uncoupling device (14).

6. The coupler arrangement of any one of claims 1 to 5, wherein the arrangement is such that a first part of the electric energy supplied to the uncoupling device (14) is used to move the uncoupling actuator (15) from the first actuator position to the second actuator position and a second part of the electric energy supplied to the uncoupling device (14) is used to hinder the uncoupling actuator (15) from returning to the first actuator position.

7. The coupler arrangement of claim 6, wherein the arrangement is such that the second part of the electric energy is used to energize an electrically actuated valve (24) so as to hold the electrically actuated valve (24) in a first valve position in which the uncoupling actuator (15) is hindered from returning to the first actuator position, wherein the shutting off of the supply of electric energy to the uncoupling device (14) causes the electrically actuated valve (24), preferably a solenoid valve, to automatically switch into a second valve position in which the uncoupling actuator (15) is no longer hindered from returning to the first actuator position, wherein preferably the uncoupling device (14) comprises an electrically driven hydraulic pump (22) configured to move the uncoupling actuator (15) from the first actuator position to the second actuator position and wherein the electrically actuated valve (24) is configured, when energized, to close a hydraulic line (25) of the uncoupling device (14).

8. The coupler arrangement of claim 6, wherein the arrangement is such that the second part of the electric energy is used to energize a clutch (20) so as to hold the clutch (20) in a first clutch mode in which the uncoupling actuator (15) is hindered from returning to the first actuator position, wherein the shutting off of the supply of electric energy to the uncoupling device (14) causes the clutch (20) to switch into a second clutch mode in which the uncoupling actuator (15) is no longer hindered from returning to the first actuator position, wherein preferably the uncoupling device (14) comprises an electromechanical drive configured to move the uncoupling actuator (15) from the first actuator position to the second actuator position or a force required to move the uncoupling actuator (15), when the clutch (20) is not energized, from the second actuator position to the first actuator position is less than 400 N, preferably less than 100 N.

9. The coupler arrangement of any one of claims 1 to 8, wherein the locking device (7) comprises: - a hook plate which is rotatable about the main pin (8) of the coupler head (1) between the coupled position and the uncoupled position and which comprises a coupling link pin on a first side relative to the main pin (8) and a hook plate recess (7A) on a second side relative to the main pin (8) opposite the first side, and - a coupling link (9) having a first end (9A) connected to the coupling link pin of the hook plate so as to be rotatable about the coupling link pin and a free second end (9B) to be received in the hook plate recess (7A) of a corresponding opposite coupler head (1), wherein preferably one or both: - the coupler head (1) comprises a latching mechanism (11) which is configured to hold the hook plate in the uncoupled position and which is automatically released mechanically when the coupler head (1) is approached by a corresponding second coupler head (1) and - the uncoupling actuator (15) or an element connected to the uncoupling actuator (15) is arranged to press against a cam surface (7B) of the hook plate when the uncoupling actuator (15) is caused to rotate the locking device (7) from its coupled position to its uncoupled position.

10. The coupler arrangement of any one of claims 1 to 9, wherein the coupler head (1) comprises a coupler head housing (6) in which at least the locking device (7) and the tension spring (10) are accommodated, wherein a drive of the uncoupling device (14) is arranged on an outside of the coupler head housing (6) and the uncoupling actuator (15) of the uncoupling device (14) extends through a wall of the coupler head housing (6) into the coupler head housing (6), wherein preferably the coupler head housing (6) has a forward end arranged to contact the forward end of a corresponding second coupler head (1) when the two coupler heads (1) are coupled together and further has a rearward end (3), wherein the main pin (8) is arranged between the forward end and the rearward end (3) and the uncoupling actuator (15) extends through a wall of the coupler head housing (6) rearward of the main pin (8).

11. The coupler arrangement of any one of claim 1 to 10, further comprising at least one of a dampening device and shock-absorbing device, wherein the coupler head (1) is configured to be connected to a car (100) of the rail vehicle with the at least one of a dampening device and shock-absorbing device arranged between the coupler head (1) and the car (100), wherein the uncoupling device (14) is configured to be mounted on the car (100), wherein the coupler arrangement preferably comprises a linking mechanism (27) which links the uncoupling actuator (15) of the uncoupling device (14) to the coupler head (1) so that movement of the uncoupling actuator (15) from the first actuator position to the second actuator position is transferred to the coupler head (1) so as to cause the locking device (7) to rotate from its coupled position to its uncoupled position, wherein more preferably the linking mechanism (27) comprises a pull cable (27A) or a hydraulic line.

12. The coupler arrangement of claim 11, wherein the coupler head (1) comprises a coupler head housing (6) with the main pin (8) extending through a wall of the coupler head housing (6), and wherein the linking mechanism (27) is connected to the main pin (8) outside of the coupler head housing (6).

13. The coupler arrangement of any one of claims 1 to 12, comprising a handle (30) configured for manually rotating the locking device (7) to its uncoupled position.

14. A freight wagon of a rail vehicle, comprising a coupler arrangement of any one of claims 10 to 13, wherein the uncoupling device (14) is mounted on the freight wagon, preferably further comprising a battery (28) attached to the freight wagon.

15. A method of uncoupling a coupler head (1) of a coupler arrangement which comprises: the coupler head (1) with - a locking device (7) which is rotatable about a main pin (8) of the coupler head (1) between a coupled position and an uncoupled position and which is configured to cooperate with a locking device (7) of a corresponding second coupler head (1) so as to couple the two coupler heads (1) together when the locking device (7) of each of the two coupler heads (1) is in its respective coupled position, and - a tension spring (10) providing a spring force configured to urge the locking device (7) towards its coupled position, and an electrically driven uncoupling device (14) having an uncoupling actuator (15) arranged to move, upon supply of electric energy to the uncoupling device (14), from a first actuator position to a second actuator position, thereby causing the locking device (7) to rotate from its coupled position to its uncoupled position against the spring force provided by the tension spring (10), wherein the method comprises the steps of: - providing a digital uncoupling signal, - upon the provision of the uncoupling signal, supplying electric energy to the uncoupling device (14) so as to move the uncoupling actuator (15) of the uncoupling device (14) from the first actuator position to the second actuator position, thereby causing the locking device (7) of the coupler head (1) to rotate from its coupled position towards its uncoupled position against the spring force provided by the tension spring (10) of the coupler head (1), and - shutting off the supply of electric energy to the uncoupling device (14), thereby allowing the uncoupling actuator (15) to return to the first actuator position.

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