COUPLER HEAD FOR A COUPLER ASSEMBLY OF A MULTI-CAR RAIL VEHICLE, COUPLER ASSEMBLY, AND METHOD OF RETROFITTING A COUPLER HEAD WITH A SAFETY DEVICE

Abstract

A coupler head for a (Janney) coupler assembly of a multi-car rail vehicle comprises a coupler head body, a knuckle pin and a knuckle which is rotatable about the knuckle pin relative to the coupler head body between a coupled position and an uncoupled position. A first lock is configured to prevent rotation of the knuckle when the knuckle is in the coupled position. A second lock is configured to prevent rotation of the knuckle when the knuckle is in the uncoupled position. The second lock is further configured to unlock when a predetermined force, which acts on the knuckle so as to rotate the knuckle toward the coupled position, is exceeded, so that the second lock no longer hinders rotation of the knuckle toward the coupled position.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority benefit under 35 U.S.C. § 119 to European Patent Application No. 23217970.5, filed Dec. 19, 2023, the entirety of which is incorporated by reference herein for all purposes.

FIELD OF THE INVENTION

The present invention relates to a coupler head for a coupler assembly of a multi-car rail vehicle, a coupler assembly, and a method of retrofitting a coupler head of a coupler assembly of a multi-car rail vehicle with a safety device.

BACKGROUND OF THE INVENTION

More specifically, the invention relates to couplers for multi-car rail vehicles, in particular to Janney couplers, also known as AAR (Association of American Railroads), CBC (Centre Buffer Coupler) or simply knuckle couplers. A Janney coupler combines a draft and a buffing gear in one, in that it transmits both tensile and compressive forces. There are various types of Janney couplers, such as the basic E-type coupler, the F-type Interlock coupler which comprises an interlocking head and which is mainly used for freight trains, and the H-type Tightlock coupler which has an even tighter interlocking head and which is mainly used on passenger trains. The H-type Tightlock coupler is particularly suitable for being designed as an automatic coupler by which also hydraulic and electric lines are coupled automatically. While the specific embodiments disclosed herein in context with the present invention relate to an H-type Tightlock coupler, the present invention can be used in connection with all types of knuckle couplers.

These couplers have in common as their basic structure a coupler head comprising a coupler head body, a knuckle, and a knuckle pin, wherein the knuckle pin connects the knuckle to the coupler head body such that the knuckle is rotatable relative to the coupler head body about a vertical axis defined by the knuckle pin. The coupler further comprises a lock. When two couplers are moved against each other in a coupling process, the knuckle of one coupler collides with the knuckle of the other coupler and is thereby caused to rotate behind the knuckle of the respective other coupler. In this situation, the lock falls down into a locking position in which it blocks the knuckle so that the two coupler heads are in a coupled state. Tensile forces between adjacent cars of the multi-car vehicle are then transferred via the knuckles. In order to unlock the two couplers again, the lock of—at least one—coupler is lifted, e.g., by means of a hand-operated lever so that the coupler heads may be moved apart, in which situation the lock in its lifted position rests on a shelf of the knuckle until the knuckle is again rotated back into its coupling position.

While it is sufficient that one of the mating knuckles is in an open position prior to the start of the coupling process, it is advantageous when the knuckles of both coupler heads are always open in their uncoupled state. This way it can be avoided that two coupler heads might make forcible contact while their knuckles are each in a closed position, which contact would ultimately result in costly damage to the couplers and coupler arrangements.

U.S. Pat. No. 7,497,345 B2 discloses an apparatus for automatically pivoting and maintaining the fully open position of the knuckle when the uncoupling mechanism is actuated. For this, a coiled torsion spring capable of continuously exerting a predetermined force is attached with one of its ends to the coupler head body and with the respective other end to the knuckle so as to generate a torque on the knuckle to pivot and maintain the knuckle in the fully open position.

However, this may bear the risk that, in case that the uncoupling mechanism is actuated unintentionally, thereby lifting the lock of the coupler head, the lock cannot fall back into its locking position because it rests on the ledge of the knuckle which was pushed open by means of the torsion spring. In general, means which could support unintentional opening of the coupler are principally to be avoided.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to overcome the prior art defects.

Accordingly, a first aspect of the present disclosure relates to a coupler assembly of a multi-car rail vehicle, in particular to a coupler head for the coupler assembly. The coupler head comprises a coupler head body, a knuckle configured for cooperating with a corresponding knuckle of another coupler head, and a knuckle pin having a knuckle pin axis. The knuckle pin is mounted to the coupler head body and the knuckle is mounted to the knuckle pin so that the knuckle is rotatable about the knuckle pin axis relative to the coupler head body between a “coupled position” and an “uncoupled position”. The coupled position relates to a state of the knuckle in which the knuckle has been rotated inward into a closed position, whereas the uncoupled position relates to a state of the knuckle in which the knuckle has been rotated outward into an open position. In the knuckle's open or uncoupled position, the coupler head is generally ready to couple. A first lock is configured to be moved, when the knuckle is in the coupled position, into a locking position in which it prevents rotation of the knuckle about the knuckle pin axis toward the uncoupled position.

In addition, there is provided a second lock. While the second lock is configured to prevent, when the knuckle is in its uncoupled, i.e. open, position, rotation of the knuckle about the knuckle pin axis toward the knuckle's coupled, i.e. closed, position, it is further configured to automatically unlock when a predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded. In this unlocked situation, the second lock no longer hinders rotation of the knuckle about the knuckle pin axis toward its coupled position.

Thus, unlike the torsion spring proposed in U.S. Pat. No. 7,497,345 B2 for automatically pivoting the knuckle and maintaining it in the fully open position when two coupler heads are being uncoupled, the second lock of the present disclosure does not hinder rotation of the knuckle-once it is unlocked. Rather, the second lock may be brought into its locking state and, thus, assume its locking function only after the knuckle has reached its open position, and then it automatically unlocks when the predetermined force acting on the knuckle in the knuckle closing direction is exceeded. This may happen when two coupler heads forcibly contact each other with their knuckles each in a closed position, for instance during a crash of two multi-car vehicles. However, when the knuckles are held in their respective open position by means of the second locks and the second locks automatically unlock during such crash, the coupler heads will automatically couple so that compression forces are perfectly transmitted between the coupler heads and coupler assemblies in the same way as when a crash occurs with the two cars already being coupled. This way, the energy absorption means which are typically provided in the coupler assemblies can absorb energy in an appropriate manner, instead of being damaged due to non-aligned forces acting between the coupler arrangements. That is, when forces applied on a knuckle coupler during crash are acting in axes different from those that were previously tested and simulated, the safety components of the coupler, in particular the energy absorption components such as a deformation unit, are most likely not to perform fully and in controlled manner, thereby causing severe damages.

In order to fulfill this function properly, the second lock should not unlock during regular driving conditions of a multi-car vehicle and, thus, bear acceleration and deceleration forces acting on the knuckle, but it should not unnecessarily hinder a coupling during a crash situation or during a regular coupling process. Preferably, automatic unlocking should occur when a force of between 250 N and 800 N, more preferably about 400 N, acts frontally on the knuckle, i.e. in a direction of the longitudinal axis of the coupler head or coupler assembly.

In a generally preferred arrangement of preventing the rotation of the knuckle about the knuckle pin axis toward the knuckle's coupled position, the second lock may simply connect the knuckle to the coupler head body and keep the knuckle in a predetermined relative position with respect to the coupler head body when the knuckle is in the uncoupled position.

Preferably, the second lock is visible from outside the coupler head when the knuckle is in the uncoupled position and in a state in which the second lock prevents the rotation of the knuckle about the knuckle pin axis toward the coupled position. This allows for a remote visible inspection of the secured open state of the coupler head.

Furthermore, the second lock is preferably accessible from outside the coupler head when the knuckle is in its uncoupled position and in a state in which the second lock prevents rotation of the knuckle about the knuckle pin axis toward the coupled position. This way, the arrangement may be made such that the second lock can easily be unlocked, for instance removed from the coupler head, in order to put the coupler head into regular operation, without a need to disassemble the coupler head. The removal may be automatic removal by remote control and/or—preferably—manual removal. The overall intention is to remove the second lock prior to a normal or controlled coupling process, not only to avoid damage to the second lock but also in order to increase the likelihood of a successful coupling without a spring force needed to be overcome the during coupling process, as would be the case in U.S. Pat. No. 7,497,345 B2 mentioned above.

Further preferably, the second lock may be arranged on a top side of the coupler head to improve its visibility and accessibility as well as to minimize any likelihood of the second lock becoming loose by the influence of gravity.

Even further preferably, at least a part of the second lock may be configured to deform and, thus, automatically unlock due to such deformation, when said predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded. The automatic unlocking of the second lock by deformation can be achieved in different ways, which can roughly be divided into “breaking locks” and “resilient locks”.

I. Breaking Lock

Thus, according to a first approach, the second lock comprises a locking element which is configured to break when said predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded. Once broken, the lock no longer hinders the rotation of the knuckle about the knuckle pin axis toward the coupled position, i.e. its closed position in which coupling may occur.

Preferably, the locking element is made of a brittle material, such as bronze or a stiff polymer, so that it does not deform but breaks. While the locking element may entirely consist of such brittle material, it may be sufficient if it comprises a limited breaking portion which, when said predetermined force is exceeded, is configured to break.

The locking element may comprise a locking pin which is configured to engage into at least one hole when the knuckle is in the uncoupled, open position. Thereby, rotation of the knuckle about the knuckle pin axis toward the coupled position is prevented. Preferably, the locking pin is removable from the hole, without breakage of the locking pin, in order to unlock the second lock. This way, the locking pin can be reused.

A minimum inner diameter of the hole into which the locking pin engages is preferably between 4 mm and 8 mm, more preferably between 5 mm and 7 mm, and most preferably about 6 mm. Accordingly, the locking pin may have a corresponding diameter of between 4 mm and 8 mm, preferably between 5 mm and 7 mm, and more preferably about 6 mm, where it engages into the at least one hole.

I.a Locking Pin Extending Through Two Holes

In a particularly preferred embodiment, the coupler head, the at least one hole for the locking pin comprises a first hole provided in the coupler head body and a second hole provided in the knuckle. The arrangement is such that, when the knuckle is in the uncoupled position, the locking pin may simultaneously engage into both the first hole and the second hole. When said predetermined force is exceeded, the locking pin will break into at least two pieces and the knuckle rotate toward its closed position. Once broken, all or some parts of the locking pin may simply fall out of the hole or holes by gravity.

Preferably, the locking pin has a weakened portion which is configured to break when said predetermined force is exceeded, wherein, when the locking pin engages into the at least one hole, the weakened portion is preferably located between the first hole and the second hole. This is the area where forces, namely shearing forces, acting on the locking pin will become strongest so that the locking pin will definitely break at this weakened portion.

The locking pin may be secured in the hole in various ways, e.g., by means of a splint, a screw threaded section, press fitting, and the like. In a preferred embodiment, the second lock comprises a resilient safety element by which the locking pin may be secured in the hole. The resilient safety element provides a resilient force. It may take the form of a leaf spring. Preferably, the resilient safety element is fixedly connected to the coupler head or to the knuckle and engages when the knuckle is in the open, uncoupled position, with the locking pin. Alternatively, the resilient safety element may be fixedly connected to the locking pin and resiliently engage with the coupler head or knuckle. This way, unintentional removal of the locking pin from the at least one hole may be prevented, while, due to its resilience, the resilient safety element may easily be disengaged from the locking pin manually, namely by acting on the resilient safety element against the resilient force, so as to permit removal of the locking pin from the at least one hole without its destruction.

The coupler head may further comprise a locking pin holder on the coupler head body, knuckle or knuckle pin, in order to hold the locking pin when the locking pin is in a state removed from the at least one hole. This way, the locking pin can be reused easily.

To this end, the second lock may further comprise a safety cable by which the locking pin is connected to the coupler head body, knuckle pin or knuckle. The safety cable has a sufficient length which allows the locking pin, while being connected to the coupler head body, knuckle pin or knuckle by means of the safety cable, both to engage into the at least one hole and to be held in the locking pin holder.

I.b Locking Pin Connected to Plunger

In another preferred embodiment, the locking element further comprises a plunger to which the locking pin is connected. The plunger is detachably connected either to the knuckle or to the coupler head body, and the at least one hole into which the locking pin engages is arranged on the respective other one of the knuckle and coupler head body. Then, removal of the locking pin from the at least one hole without breakage of the locking element requires detaching the plunger from the knuckle or coupler head body, respectively.

Once the plunger has been detached from the knuckle or coupler head body, it may be reconnected thereto in a different orientation in which it does not hinder rotation of the knuckle about the knuckle pin axis toward its closed or coupled position. This may be achieved by turning the plunger about 180° and reattaching it at connection points which are identical to the connection points prior to the detachment. Thus, after reattachment, the plunger with the locking pin connected thereto faces backward or upward so that the locking pin is out of the way during the subsequent coupling.

The locking pin may have a weakened portion configured to break when said predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded. When the locking pin engages into the at least one hole, the weakened portion is preferably located at a position outside the at least one hole, i.e. between the plunger and the hole. This is the area where forces, namely shearing forces, acting on the locking pin will become strongest so that the locking pin will definitely break at this weakened portion.

An elastomeric or rubber sleeve may be provided between an outer surface of the locking pin and an inner surface of the at least one hole when the locking pin engages into the at least one hole. This will prevent rattling noise when the rail vehicle is driving.

Couplers usually have to fulfill certain standards, and Janney couplers typically have a so-called “flag hole” in the front end of the knuckle. The flag hole usually extends vertically all the way through the knuckle. In the above-mentioned embodiments, the hole for the locking pin may advantageously be formed by the flag hole of the knuckle.

II. Resilient Lock

According to a second approach, the second lock comprises a locking element which is configured to resiliently move away, rather than break, when said predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded. Once the locking element has moved out of the way, the lock no longer hinders the rotation of the knuckle about the knuckle pin axis toward the coupled position, i.e. its closed position in which coupling may occur. An advantage of the resilient lock over a breaking lock resides in the reusability of the resilient lock.

As such, the second lock may comprise a resilient element and a locking element. The resilient element is arranged to provide, when the knuckle is in the uncoupled position, a resilient force which urges the locking element into a locking position in which the locking element prevents the rotation of the knuckle about the knuckle pin axis. And the locking element is arranged to move out of such locking position against the resilient force of the resilient element when said predetermined force acting on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position is exceeded. Thus, in case two cars crash with their respective couplers facing each other, the locking elements of the coupler heads move out of their locking position against the resilient force of the corresponding resilient element, thereby allowing their knuckles to rotate and ultimately couple. Afterwards, when the couplers have been uncoupled again, the knuckles may again be held in their open, uncoupled position by means of the same locking element being urged into its locking position by way of the associated resilient element.

The resilient element of the second lock may be attached either to the coupler head body or knuckle pin or to the knuckle, whereas the locking element may be configured to engage, when the knuckle is in the uncoupled position, with the respective other one of the coupler head body/knuckle pin and knuckle. This way, the knuckle can be held in a fixed position relative to the coupler head body until the predetermined force acting on the knuckle is exceeded and overcomes the resilient force of the resilient element.

According to a preferred embodiment, the locking element may engage a depression or hole when the knuckle is in the uncoupled position. Preferably, the flag hole of the knuckle, which is usually not used, is employed as the hole, so that retrofitting existing couplers with the second lock is kept relatively simple.

In this context, the locking element may preferably have a sloped surface by which it engages the hole or depression when the knuckle is in the uncoupled position. Thereby, damage to the locking element can be prevented when the locking element is forcibly moved out of the depression or hole.

II.a Leaf Spring

In a particularly preferred embodiment, the resilient element takes the form and function of a leaf spring. An advantage of a leaf spring over other spring elements consists in that the manufacture of a leaf spring is relatively simple and the required mounting space relatively little. In particular, the locking element may easily be integrated as a part of the leaf spring so that the locking element and resilient element form an integral unit.

II.b Plunger with Compression Spring

Alternatively, the resilient element may comprise a compression spring which is arranged on a plunger. For instance, the plunger may be mounted to the coupler head body, or possibly to the knuckle pin. In any case, the compression spring may be arranged to urge the locking element into its locking position. For instance, the compression spring may urge the locking element into the flag hole of the knuckle pin or into a different hole or depression on the knuckle pin until said predetermined force acting on the knuckle pin is exceeded.

III. Method of Retrofitting

According to a second aspect of the present disclosure, there is provided a method of retrofitting a coupler head of a coupler assembly of a multi-car rail vehicle with a safety device. The safety device has the purpose of maintaining the knuckle of a knuckle coupler in an open position under normal conditions, i.e. driving conditions. As such, the safety device may take the form of the above-described second lock. Thus, the coupler head to be retro-fitted with the safety device comprises a coupler head body, a knuckle configured for cooperating with a corresponding knuckle of another coupler head, and a knuckle pin having a knuckle pin axis, wherein the knuckle pin is mounted to the coupler head body and the knuckle is mounted to the knuckle pin so that the knuckle is rotatable about the knuckle pin axis relative to the coupler head body between a coupled position and an uncoupled position. The coupler head further comprises a first lock which is configured to be moved, when the knuckle is in the coupled position, into a locking position in which it prevents rotation of the knuckle about the knuckle pin axis toward the uncoupled position.

Then, the method comprises the following steps:

• • providing the safety device in the form of a (second) lock, and
  • mounting the (second) lock on the coupler head in such a manner that, when the knuckle is in the uncoupled position, the second lock is able to:
    • (a) prevent rotation of the knuckle about the knuckle pin axis toward the coupled position, and
    • (b) unlock, when a predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded, so that the second lock no longer hinders rotation of the knuckle about the knuckle pin axis toward the coupled position.

As mentioned before, the predetermined force may be a force acting frontally on the knuckle, i.e. in a direction of the longitudinal axis of the coupler head or coupler assembly, which force may be in the range of between 250 N and 800 N, preferably about 400 N. As already explained in connection with the above-described coupler head, the safety device may be arranged on the coupler head so as to keep the knuckle in a predetermined relative position with respect to the coupler head body when the knuckle is in its uncoupled position.

Furthermore, the second lock may be arranged such that, when the knuckle is in the uncoupled position and the second lock is in a state in which it prevents rotation of the knuckle about the knuckle pin axis toward the coupled position, the second lock is preferably visible from outside the coupler head.

Even further, the second lock may be arranged such that, when the knuckle is in its uncoupled position and the second lock is in a state in which it prevents rotation of the knuckle about the knuckle pin axis toward the coupled position, the second lock is preferably accessible and unlockable from outside the coupler head without a need to disassemble the coupler head.

In particular, the second lock may be arranged on a top side of the coupler head for the reasons set out above.

As also mentioned before, at least a part of the second lock may be configured to deform, for instance break or flex, when said predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded.

III.1 Breaking Lock

In line with the first approach, the second lock may comprise a locking element which is configured to break when said predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded. In particular, the locking element may comprise a locking pin, wherein the method may comprise the step of drilling at least one hole into the coupler head, in which case the locking pin may be configured to, when the knuckle is in the uncoupled position, engage into the at least one hole so as to prevent the rotation of the knuckle about the knuckle pin axis toward the coupled position. Further, the locking pin may be removable from the at least one hole, without breakage of the locking pin, in order to unlock the second lock. In particular, the at least one hole may be drilled with an inner diameter of between 4 mm and 8 mm, preferably between 5 mm and 7 mm, more preferably about 6 mm.

III.1.a Locking Pin Extending Through Two Holes

The step of drilling the at least one hole may comprise drilling a first hole in the coupler head body and a second hole in the knuckle, wherein the locking pin may be configured to, when the knuckle is in the uncoupled position, simultaneously engage into both the first hole and the second hole.

A resilient safety element, which provides a resilient force, may be fixedly connected to one of the coupler head and knuckle in such a manner that, when the knuckle is in the uncoupled position, the resilient safety element is able to perform two functions, namely (a) engage with the locking pin so as to prevent unintentional removal of the locking pin from the at least one hole, and (b) be disengaged from the locking pin by acting on the resilient safety element against the resilient force so as to allow removing the locking pin from the at least one hole.

In addition, a locking pin holder may be fixedly connected to the coupler head body, knuckle or knuckle pin, wherein the locking pin holder is configured to hold the locking pin when the locking pin is in a state removed from the first and second holes.

Furthermore, the method may comprise the steps of:

• • providing a safety cable and
  • connecting the locking pin to the coupler head body, knuckle pin or knuckle by means of the safety cable,
  • wherein the safety cable is provided with a sufficient length which allows the locking pin, while being connected to the coupler head body, knuckle pin or knuckle by means of the safety cable, to engage into the first and second holes and to be held in the locking pin holder.

III.1.b Locking Pin Connected to Plunger

Alternatively, where the locking element comprises a plunger to which the locking pin is connected, the retrofitting method may comprise the steps of:

• • detachably connecting the plunger to one of the knuckle and coupler head body and
  • drilling the at least one hole in the respective other one of the knuckle and coupler head body,
  • wherein the arrangement is made such that removal of the locking pin from the at least one hole without breakage of the locking element requires detaching the plunger from the knuckle or coupler head body, respectively.

In particular, the locking pin may have a weakened portion configured to break when said predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded. In this case, the arrangement is preferably made such that, when the locking pin engages into the at least one hole, the weakened portion is located outside the at least one hole between the plunger and the hole.

The method may further comprise a step of providing an elastomeric or rubber sleeve on an outer surface of the locking pin or an inner surface of the at least one hole such that the elastomeric or rubber sleeve is arranged between an outer surface of the locking pin and an inner surface of the at least one hole when the locking pin engages into the at least one hole. Preferably, the at least one hole is a flag hole of the knuckle.

III.2. Resilient Lock

In line with the second approach, the second lock may comprise a resilient element and a locking element. In this case, the method may comprise the steps of:

• • arranging the resilient element such that, when the knuckle is in the uncoupled position, a resilient force of the resilient element urges the locking element into a locking position in which it prevents the rotation of the knuckle about the knuckle pin axis, and
  • arranging the locking element such that it moves, when said predetermined force acting on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position is exceeded, out of its locking position against the resilient force of the resilient element.

The resilient element of the second lock may be attached to one of the coupler head body or knuckle pin, on the one hand, and knuckle, on the other hand, such that the locking element of the second lock is able to engage, when the knuckle is in the uncoupled position, with the respective other one of the coupler head body or knuckle pin, on the one hand, and knuckle, on the other hand.

In particular, the step of arranging the locking element may be such that the locking element is able to engage a depression or hole when the knuckle is in the uncoupled position, wherein the hole is preferably the flag hole of the knuckle. Again, for reasons already set out above, the locking element may have a sloped surface by which it engages the hole or depression when the knuckle is in the uncoupled position.

III.2.a Leaf Spring

In one embodiment, the resilient element may be provided as a leaf spring, wherein preferably the locking element is provided so as to form an integral part of the leaf spring.

III.2.b Plunger with Compression Spring

In another embodiment, the resilient element may comprise a compression spring arranged on a plunger, wherein the arrangement of the resilient element is preferably made such that the compression spring is able to urge the locking element into the locking position.

IV. Coupler Assembly

Finally, there is provided a coupler assembly for a car of a multi-car rail vehicle, the coupler assembly comprising a coupler head as described above and further comprising energy absorption means configured to absorb energy when the coupler head collides with a corresponding coupler head of another car of the multi-car vehicle. The energy absorption means usually make up part of a draft gear by which the coupler head is attached to the car of the multi-car vehicle. The draft gear and, in particular, the energy absorption means disposed therein may get damaged in case that forces act frontally on the coupler head which are not coaxial with the longitudinal axis of the draft gear.

BRIEF DESCRIPTION OF THE DRAWINGS

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, however, is not limited to the specific embodiments disclosed in the drawings. In the drawings:

FIGS. 1A, 1B are different perspective views of a coupler assembly according to a first embodiment,

FIG. 2 is an enlarged perspective view of a part of the coupler head of the coupler assembly shown in FIGS. 1A and 1B, illustrating a (second) lock,

FIG. 3 shows the coupler head and (second) lock of FIG. 2 partly in cross-section, illustrating a locking pin of the (second lock),

FIG. 4 shows a holder on the coupler head for holding the locking pin of the (second) lock shown in FIG. 3,

FIG. 5 illustrates a safety cable by which the locking pin shown in FIGS. 3 and 4 is connected to the coupler head,

FIG. 6 shows the coupler head with a (second) lock according to a second embodiment,

FIG. 7 shows the (second) lock of the second lock of the second embodiment of FIG. 6 in isolation,

FIG. 8 shows the coupler head with a (second) lock according to a third embodiment,

FIG. 9 shows the coupler head with a (second) lock according to a fourth embodiment,

FIG. 10 shows the coupler head with a (second) lock according to a fifth embodiment and

FIG. 11 shows a locking element of the (second) lock of FIG. 10 in detail.

DETAILED DESCRIPTION

FIGS. 1A and 1B are different perspective views of a coupler assembly which comprises a coupler head 1 and a draft gear 2. The draft gear 2 connects the coupler head 1 to the car body of a car of a multi-car vehicle by means of a mounting plate 3. The draft gear is designed to absorb the stresses during coupling and train acceleration and, for this purpose, incorporates certain energy-absorbing means. In this example, this includes a hydraulic damper, a rubber bearing and a deformation tube. The coupler head 1 includes a coupler head body 10 and a knuckle 11 and further a knuckle pin 12. The knuckle pin 12 is secured in the coupler head body 10 by two splints at the top end and bottom end, respectively, of the knuckle pin 12. The knuckle pin 12 has a knuckle pin axis A and is mounted to the coupler head body 10 so that the knuckle pin axis A is vertical. The knuckle 11 is mounted on the knuckle pin 12 so as to be rotatable about the knuckle pin axis A between an open position, which is shown in FIGS. 1A and 1B, and a closed position. In the opened position, the coupler head 1 is ready for coupling in that it can receive another knuckle of a corresponding coupler head, which other knuckle may be in the open or closed position. During the coupling process, the other knuckle of the corresponding coupler head pushes against a tail 11A of the knuckle 11 so that the knuckle 11 rotates about the knuckle pin axis A until the knuckle 11 (or possibly the knuckles of both coupler heads) reaches its closed position. In this position a first lock, which is located inside the coupler head body 10 behind the pressure plate 13 (and is therefore not visible here) and rests on a knuckle shelf 11B, falls down by gravity and thereby blocks any rotation of the knuckle 11 back toward its open position. In this closed position (not illustrated) the knuckles 11 of both couplers are interlocked behind each other and blocked from further rotation, which constitutes the coupled state of the coupler heads. Uncoupling is performed by means of a coupler lock lifter (not shown), which, in a first step, lifts the first lock above the knuckle shelf 11B and, in a second step, pushes the knuckle 11 by means of a knuckler thrower (not shown) so as to rotate the knuckle 11 back toward its open position.

As can be seen from the guard arm 14 on the lateral side of the coupler head body 10, the coupler head shown in FIGS. 1A and 1B is an H-type Tightlock coupler head. The guard arm 14 is received in a corresponding pocket 15 on the respective other lateral side of the coupler head body 10.

FIG. 2 is an enlarged perspective view of a part of the coupler head 1 shown in FIGS. 1A and 1B and illustrates a second lock 20 according to a first embodiment. The second lock 20 is configured to prevent rotation of the knuckle 11 about the knuckle pin axis A toward its coupled or closed position when the knuckle 11 is in the uncoupled position, which position is shown in FIG. 2. This is illustrated in more detail in FIG. 3 which shows the coupler head body 10 and second lock 20 partly in cross-section. More specifically, as in all embodiments described herein, the second lock 20 is configured to lock the knuckle 11 to the coupler head body 10 and keep the knuckle 11 in a predetermined relative position with respect to the coupler head body when the knuckle 11 is in the uncoupled position. For this purpose, according to this first embodiment, the second lock 20 comprises a locking pin 21 which extends through a first hole 22 in the coupler head body 10 and a second hole 23 in the knuckle 11. As can be seen, the locking pin 21 is arranged on a top side of the coupler head and extends from the coupler head body 10 so that it is both visible and easily accessible from outside the coupler head. This way, it can be easily verified whether the second lock 20 is in place to block rotation of the knuckle 11, and the locking pin 21 can be easily removed from the coupler head 1 without a need to disassemble the coupler head 1, thereby unlocking the second lock 20.

At least the locking pin 21 of the second lock 20 is spaced apart from a vertical mid-plane of the coupler head 1, wherein the vertical mid-plane intersects a longitudinal center axis of the coupler assembly. This is the case for the locking elements of all embodiments disclosed herein.

A core feature of the second lock 20 of this embodiment consists in that the second lock 20, more specifically a part thereof, can break, namely the locking pin 21. That is, when a predetermined force acts on the knuckle 11 so as to rotate the knuckle 11 about the knuckle pin axis A toward the knuckle's coupled position (not shown) is exceeded, the locking pin 21 will break. Thus, it is preferable that the locking pin 21 is made from brittle material, such as bronze or a stiff polymer. For most applications, also in relation to the other embodiments disclosed herein, the second lock 20 should unlock, here “break”, when a force acting frontally in the knuckle 11 is in the range of 250 N to 800 N (or higher), a preferred predetermined breaking force being about 400 N.

The locking pin 21 preferably fits tightly in the first and second holes 22, 23, wherein the holes 22, 23 may have an inner diameter of between 4 mm and 8 mm, preferably between 5 mm and 7 mm and more preferably about 6 mm. Thus, the diameter of the locking pin 21 is about the same as that of the holes 22, 23 and may be slightly smaller than this in order to allow easy removal of the locking pin 21 from the coupler head 1.

In this first embodiment, the locking pin 21 is provided with a weakened portion 21A which is configured to break when said predetermined force is exceeded. The weakened portion 21A is located between the first hole 22 in the coupler head body 10 and the second hole 23 in the knuckle 11. In the area of the weakened portion 21A, the diameter of the locking pin 21 is accordingly reduced.

The second lock 20 further comprises a resilient safety element 24 which provides a resilient force. In the embodiment shown, the resilient safety element 24 takes the form of a leaf spring. The resilient safety element 24 is fixedly connected to the coupler head body 10 with one end 24A thereof and engages with the locking pin 21 with its respective other end 24B. Alternatively, the resilient safety element 24 may be fixedly connected to the knuckle 11. A recess 21B is provided on a top end of the locking pin 21 extending from the coupler head body 10, and the resilient safety element 24 engages into such recess 21B with its free end 24B so as to prevent unintentional removal of the locking pin 21 from the holes 22, 23. The resilient safety element 24 can be easily disengaged from the locking pin 21 by pushing the free end 24B of the resilient safety element 24 sideways against the resilient force so that the locking pin 21 can be removed from the holes 22, 23 without destruction of the locking pin 21. This is done prior to an intentional coupling process.

Since the locking pin 21 is supposed to be reused and replaced into the holes 22, 23 after the next uncoupling process, it may be held in a locking pin holder 25 meanwhile. The locking pin holder 25 is provided on a side of the coupler head body 10, as illustrated in FIG. 4. Thus, the locking pin holder 25 may hold the locking pin 21 in a state when it is removed from the first and second holes 22, 23.

In addition, the second lock 20 may further comprise a safety cable 25A which is illustrated in FIGS. 1A and 1B and, in further detail in FIG. 5, which is a partial view of FIG. 1A. The safety cable 25A connects the locking pin 21 to the coupler head body 10, but it may alternatively connect the locking pin 21 to the knuckle pin 12 or the knuckle 11. The safety cable 25A has a length sufficient to allow the locking pin 21 to engage into the first and second holes 22, 23 and to be held in the locking pin holder 25 on the side of the coupler head body 10. In the embodiment shown, there are shown two locking pins 21, one positioned in the first and second holes 22, 23 and one being held in the locking pin holder 25.

It is important to note that in all embodiments disclosed herein the second lock 20 can be retro-fitted to existing coupler heads, namely in this first embodiment by drilling the first and second holes 22, 23 into the coupler head body 10 and knuckle 11, respectively, attaching the resilient safety element 24 on top of the coupler head body 10 with a first fixed end 24A thereof, and attaching the locking pin holder 25 to a side of the coupler head body 10.

FIG. 6 shows the coupler head with a second lock 20 according to a second embodiment. The second embodiment differs from the first embodiment only in the second lock 20. In this case, the second lock 20 comprises a plunger 26 with a fixed end 26A mounted on top of the coupler head body 10 and a free end 26B. A locking pin 21 is connected to the free end 26B of the plunger 26 and extends into the flag hole 11C of the knuckle 11. Most, if not all, standardized knuckle couplers have such a flag hole 11C. The flag hole 11C runs all the way through the knuckle 11 parallel to the knuckle pin axis A. Rather than extending into the flag hole 11C, the locking pin 21 could likewise extend into a different hole or depression in the knuckle 11 or extend along an inward side of the knuckle 11 so as to prevent its inward rotation toward its closed position. The fixed end 26A may alternatively be fixed to the knuckle 11, in which case the pin 21 attached to the free end 26B of the plunger 26 extends into a hole or depression on the coupler head body 10. The locking pin may be shorter than shown in FIG. 6.

As can be seen from FIG. 6, the fixed end 26A of the plunger 26 is fixedly attached to the top of the coupler head body 10 by means of a buckle 27, more specifically by two buckles on opposite sides of the coupler head body 10. The buckles, in turn, are mounted and can be retro-fitted on the coupler head body 10. By releasing the buckles 27 on each side of the coupler head body 10, the plunger 26 can be removed along with the locking pin 21 without breaking any part of the second lock 20. Once unlocked, the locking element, i.e. the plunger 26 with the locking pin 21, can be simply turned by 180° around a vertical axis and reattached at the same connection points, i.e. with the same buckles 27, by which it was attached to the coupler head body 10 in the first place.

Importantly, the arrangement is such that the second lock 20, i.e. a part thereof, breaks when it is in its locked position (shown in FIG. 6) and collides with a corresponding coupler head of a second car, thereby allowing the two coupler heads to couple. More specifically, the locking pin 21 may have a weakened portion (not shown), similar to the weakened portion of the locking pin 21 of the first embodiment, so that, when a predetermined force acting on the knuckle 11 is exceeded, the locking pin 21 breaks at said weakened portion. For this purpose, the weakened portion of the locking pin 21 may be located outside the flag hole 11C between the plunger 26A and the flag hole 11C.

FIG. 7 shows the second lock 20 in isolation. As shown, the second lock 20 comprises the plunger 26, the locking pin 21 and the two buckles 27 on either side of the fixed end 26A of the plunger 26. The locking pin 21 may be shorter than shown, as it is sufficient that it extends into the flag hole 11C. The outer diameter of the locking pin 21 corresponds to or is slightly smaller than the inner diameter of the flag hole 11C. Either the entire plunger 26 and locking pin 21 are made from a brittle material, such as bronze or a stiff polymer, or at least the portion thereof which is supposed to break in the case of a collision should be made from such material.

FIG. 8 shows the coupler head body 10 with a second lock 20 according to a third embodiment. The second lock 20 of the third embodiment is similar to that of the second embodiment in that it comprises a plunger 26 having a fixed end 26A and a free end 26B, wherein a locking pin 21 is attached to the free end 26B of the plunger 26 and extends vertically from above into the flag hole 11C. It differs from the second lock 20 of the second embodiment in that, apart from the plunger 26 being substantially smaller in size, the plunger 26 is screwed onto the top of the coupler head body 10 with its fixed end 26A, on the one hand, and, more importantly, comprises an elastomeric or rubber sleeve 28 arranged between an outer surface of the locking pin 21 and an inner surface of the flag hole 11C, on the other hand. The elastomeric or rubber sleeve 28 may either be fixedly attached to the locking pin 21 or mounted in the flag hole 11C. Alternatively, the elastomeric or rubber sleeve 28 may be entirely separate from the locking pin 21 and flag hole 11C. The purpose of the elastomeric or rubber sleeve 28 is to avoid a rattling noise when the multi-car vehicle is driving.

Again, the plunger 26 may be detached from the coupler head body 10 in order to unlock the second lock 20. It may be reconnected thereto by turning the plunger by 180° about a vertical axis or even about a horizontal axis and reattaching it at the same connection points 26C at which the plunger 26 is attached when it is in its locked position, shown in FIG. 8.

Again, the second lock 20 is supposed to break when a predetermined force acting on the knuckle 11 is exceeded. Therefore, also the locking pin 21 of this third embodiment has a weakened portion 21A of reduced diameter at a location between the free end 26B of the plunger 26 and the flag hole 11C.

FIG. 9 shows the coupler head body 10 with a second lock 20 according to a fourth embodiment. This embodiment differs from the embodiments described above in that the second lock 20 is not supposed to break. Rather, the second lock 20 comprises a resilient element 29 and a locking element 30. The resilient element 29 has a fixed end 26C connected to the top of the coupler head 10 and a free end 29B to which the locking element 30 is (here: integrally) connected. As can be seen in FIG. 9 in comparison to FIG. 8, the resilient element 29 is similar to the plunger 26 of the third embodiment, except that its purpose is to be flexible when mounted to the coupler head body 10 by means of screws or the like at the connecting points 26C. Thus, the plunger or resilient element 29 has substantially the function of a leaf spring. The locking element 30 at the free end 29B of the resilient element 29 reaches into the flag hole 11C (or into any other hole or depression) of the knuckle 11. However, unlike the locking pin 21 in the above-described embodiments, the locking element 30 has a sloped surface by which it engages the flag hole 11C. Therefore, when a force acts frontally on the knuckle 11, the knuckle 11 is urged to rotate about the knuckle pin axis A, thereby creating a force on the sloped surface 31 of the locking element 30 which includes a vertical force component that ultimately causes the resilient element 29 to flex upward and give way for the knuckle 11 to rotate toward its closed position. Thus, the second lock 20 unlocks automatically when a predetermined force is exceeded, without any part thereof breaking. Accordingly, there is no need to replace any part of the second 5 lock 20 of this fourth embodiment in case of an unintentional collision of two coupler heads. Furthermore, there is no need to detach and reattach the resilient element 29 in order to unlock and lock, respectively, the second lock 20.

FIG. 10 shows a coupler head body 10 with a second lock 20 according to a fifth embodiment. The fifth embodiment substantially corresponds to the fourth embodiment in function. However, the plunger 26 is not resilient, unlike the resilient element 29 in the fourth embodiment. Instead, the plunger 26 is substantially stiff and has movably attached to its free end 26B the locking element 30 with the sloped surface 30A extending into the flag hole 11C. This is shown in more detail in FIG. 11, according to which a pin 30B of the locking element 30 is vertically movable within the free end 26B of the plunger 26 and held in its lower vertical position by means of a resilient element 29 which may take the form of a compression spring as shown in FIG. 11. Again any force acting frontally on the knuckle 11 is transferred onto the sloped surface 30A of the locking element 30 so as to create a vertical force component which urges the pin 30B vertically upward against the resilient force of the resilient element 29 (compression spring). Once a predetermined force acting on the knuckle 11 is exceeded, the locking element 11 will lift out of the flag hole 11C, thereby giving free the way for the knuckle 11 to rotate toward its closed position.

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 head (1) for a coupler assembly of a multi-car rail vehicle, comprising:
    • a coupler head body (10), a knuckle (11) configured for cooperating with a corresponding knuckle (11) of another coupler head (1), and a knuckle pin (12) having a knuckle pin axis (A), wherein the knuckle pin (12) is mounted to the coupler head body (10) and the knuckle (11) is mounted to the knuckle pin (12) so that the knuckle (11) is rotatable about the knuckle pin axis (A) relative to the coupler head body (10) between a coupled position and an uncoupled position, and
    • a first lock which is configured to be moved, when the knuckle (11) is in the coupled position, into a locking position in which it prevents rotation of the knuckle (11) about the knuckle pin axis (A) toward the uncoupled position,
    • characterized by a second lock (20) which is configured to prevent, when the knuckle (11) is in the uncoupled position, rotation of the knuckle (11) about the knuckle pin axis (A) toward the coupled position, wherein the second lock (20) is further configured to unlock when a predetermined force, which acts on the knuckle (11) so as to rotate the knuckle (11) about the knuckle pin axis (A) toward the coupled position, is exceeded, so that the second lock (20) no longer hinders rotation of the knuckle (11) about the knuckle pin axis (A) toward the coupled position.
  • 2. The coupler head (1) of paragraph 1, wherein the second lock (20) is configured to connect the knuckle to the coupler head body (10) and keep the knuckle (11) in a predetermined relative position with respect to the coupler head body (10) when the knuckle (11) is in the uncoupled position.
  • 3. The coupler head (1) of paragraph 1 or 2, wherein, when the knuckle (11) is in the uncoupled position and the second lock (20) is in a state in which it prevents rotation of the knuckle (11) about the knuckle pin axis (A) toward the coupled position, the second lock (20) is visible from outside the coupler head (1).
  • 4. The coupler head (1) of any one of paragraphs 1 to 3, wherein, when the knuckle (11) is in the uncoupled position and the second lock (20) is in a state in which it prevents rotation of the knuckle (11) about the knuckle pin axis (A) toward the coupled position, the second lock (20) is accessible and unlockable from outside the coupler head (1) without a need to disassemble the coupler head (1).
  • 5. The coupler head (1) of any one of paragraphs 1 to 4, wherein the second lock (20) is arranged on a top side of the coupler head (1).
  • 6. The coupler head (1) of any one of paragraphs 1 to 5, wherein at least a part of the second lock (20) is configured to deform when said predetermined force, which acts on the knuckle (11) so as to rotate the knuckle (11) about the knuckle pin axis (A) toward the coupled position, is exceeded.

I. Breaking Lock

• • 7. The coupler head (1) of any one of paragraphs 1 to 6, wherein the second lock (20) comprises a locking element (30) which is configured to break when said predetermined force, which acts on the knuckle (11) so as to rotate the knuckle (11) about the knuckle pin axis (A) toward the coupled position, is exceeded.
  • 8. The coupler head (1) of paragraph 7, wherein the locking element (30) comprises a breaking portion which, when said predetermined force acting on the knuckle (11) so as to rotate the knuckle (11) about the knuckle pin axis (A) toward the coupled position is exceeded, is configured to break, wherein at least said breaking portion of the locking element (30) is made of bronze or stiff polymer.
  • 9. The coupler head (1) of paragraph 7 or 8, wherein the locking element (30) comprises a locking pin (21) which is configured to, when the knuckle (11) is in the uncoupled position, engage into at least one hole (11C; 22, 23), thereby preventing the rotation of the knuckle (11) about the knuckle pin axis (A) toward the coupled position, wherein the locking pin (21) is removable from the at least one hole (11C; 22, 23), without breakage of the locking pin (21), in order to unlock the second lock (20).
  • 10. The coupler head (1) of paragraph 9, wherein, where the locking pin (21) engages into the at least one hole (11C; 22, 23), a minimum inner diameter of the at least one hole (11C; 22, 23) is between 4 mm and 8 mm, preferably between 5 mm and 7 mm, more preferably about 6 mm.

I.a Locking Pin Extending Through Two Holes

• • 11. The coupler head (1) of paragraph 9 or 10, wherein the at least one hole (22, 23) comprises a first hole (22) provided in the coupler head body (10) and a second hole (23) provided in the knuckle (11), and wherein the locking pin (21) is configured to, when the knuckle (11) is in the uncoupled position, simultaneously engage into both the first hole (22) and the second hole (23) and break when said predetermined force, which acts on the knuckle (11) so as to rotate the knuckle (11) about the knuckle pin axis (A) toward the coupled position, is exceeded.
  • 12. The coupler head (1) of paragraph 11, wherein the locking pin (21) has a weakened portion (21A) configured to break when said predetermined force, which acts on the knuckle (11) so as to rotate the knuckle (11) about the knuckle pin axis (A) toward the coupled position, is exceeded, wherein, when the locking pin (21) engages into the first and second hole (22, 23), the weakened portion (21A) is located between the first hole (22) and the second hole (23).
  • 13. The coupler head (1) of paragraph 11 or 12, wherein the second lock (20) further comprises a resilient safety element (24) providing a resilient force, wherein the resilient safety element (24) is fixedly connected to one of the coupler head body (10) and knuckle (11) and configured to engage, when the knuckle (11) is in the uncoupled position, with the locking pin (21) so as to prevent unintentional removal of the locking pin (21) from the first and second hole (22, 23), and wherein the resilient safety element (24) is further configured to be disengaged from the locking pin (21) by acting on the resilient safety element (24) against the resilient force so as to allow removing the locking pin (21) from the first and second hole (22, 23).
  • 14. The coupler head (1) of any one of paragraphs 11 to 13, further comprising a locking pin holder (25) on the coupler head body (10), knuckle (11) or knuckle pin (12), wherein the locking pin holder (25) is configured to hold the locking pin (21) when the locking pin (21) is in a state removed from the first and second hole (22, 23).
  • 15. The coupler head (1) of paragraph 14, wherein the second lock (20) further comprises a safety cable (25A) by which the locking pin (21) is connected to the coupler head body (10), knuckle pin (12) or knuckle (11), wherein the safety cable (25A) has a sufficient length which allows the locking pin (21), while being connected to the coupler head body (10), knuckle pin (12) or knuckle (11) by means of the safety cable (25A), to engage into the first and second hole (22, 23) and to be held in the locking pin holder (25).

I.b Locking Pin Connected to Plunger

• • 16. The coupler head (1) of paragraph 9 or 10, wherein the locking element (30) further comprises a plunger (26) to which the locking pin (21) is connected, wherein the plunger (26) is detachably connected to one of the knuckle (11) and coupler head body (10) and the at least one hole (11C) is arranged on the respective other one of the knuckle (11) and coupler head body (10), wherein removal of the locking pin (21) from the at least one hole (11C) without breakage of the locking element (30) requires detaching the plunger (26) from the knuckle (11) or coupler head body (10), respectively.
  • 17. The coupler head (1) of paragraph 16, wherein the plunger (26) is configured to, once detached from the knuckle (11) or coupler head body (10), be reconnected thereto, in a manner which does not hinder rotation of the knuckle (11) about the knuckle pin axis (A) toward the coupled position, by turning the plunger (26) about 180° and reattaching it at connection points (26C) which are identical to connection points (26C) prior to the detachment.
  • 18. The coupler head (1) of paragraph 16 or 17, wherein the locking pin (21) has a weakened portion (21A) configured to break when said predetermined force, which acts on the knuckle (11) so as to rotate the knuckle (11) about the knuckle pin axis (A) toward the coupled position, is exceeded, wherein, when the locking pin (21) engages into the at least one hole (11C), the weakened portion (21A) is located outside the at least one hole (11C) between the plunger (26) and the at least one hole (11C).
  • 19. The coupler head (1) of any one of paragraphs 16 to 18, further comprising an elastomeric or rubber sleeve (28) which is provided between an outer surface of the locking pin (21) and an inner surface of the at least one hole (11C) when the locking pin (21) engages into the at least one hole (11C).
  • 20. The coupler head (1) of any one of paragraphs 16 to 19, wherein the at least one hole (11C) is a flag hole of the knuckle (11).

II. Resilient Lock

• • 21. The coupler head (1) of any one of paragraphs 1 to 6, wherein the second lock (20) comprises a resilient element (29) and a locking element (30), wherein the resilient element (29) is arranged to provide, when the knuckle (11) is in the uncoupled position, a resilient force urging the locking element (30) into a locking position in which the locking element (30) prevents the rotation of the knuckle (11) about the knuckle pin axis (A), and wherein the locking element (30) is arranged to move, when said predetermined force acting on the knuckle (11) so as to rotate the knuckle (11) about the knuckle pin axis (A) toward the coupled position is exceeded, out of the locking position against the resilient force of the resilient element (29).
  • 22. The coupler head (1) of paragraph 21, wherein the resilient element (29) of the second lock (20) is attached to one of the coupler head body (10) or knuckle pin (12), on the one hand, and knuckle (11), on the other hand, and wherein the locking element (30) of the second lock (20) is configured to engage, when the knuckle (11) is in the uncoupled position, with the respective other one of the coupler head body (10) or knuckle pin (12), on the one hand, and knuckle (11), on the other hand.
  • 23. The coupler head (1) of paragraph 21 or 22, wherein the locking element (30) engages a depression or hole (11C) when the knuckle (11) is in the uncoupled position.
  • 24. The coupler head (1) of paragraph 23, wherein the hole (11C) is a flag hole of the knuckle (11).
  • 25. The coupler head (1) of paragraph 23 or 24, wherein the locking element (30) has a sloped surface (30A) by which it engages the hole (11C) or depression when the knuckle (11) is in the uncoupled position.

II.a Leaf Spring

• • 26. The coupler head (1) of any one of paragraphs 21 to 25, wherein the resilient element (29) is a leaf spring.
  • 27. The coupler head (1) of paragraph 26, wherein the locking element (30) forms an integral part of the leaf spring.
    II.b Plunger with Compression Spring
  • 28. The coupler head (1) of any one of paragraphs 21 to 25, wherein the resilient element (29) comprises a compression spring arranged on a plunger (26).
  • 29. The coupler head (1) of paragraph 28, wherein the resilient element (29) is configured to urge the locking element (30) into the locking position.

III. Method of Retrofitting

• • 30. A method of retrofitting a coupler head (1) of a coupler assembly of a multi-car rail vehicle with a safety device, wherein the coupler head (1) comprises:
    • a coupler head body (10), a knuckle (11) configured for cooperating with a corresponding knuckle (11) of another coupler head (1), and a knuckle pin (12) having a knuckle pin axis (A), wherein the knuckle pin (12) is mounted to the coupler head body (10) and the knuckle (11) is mounted to the knuckle pin (12) so that the knuckle (11) is rotatable about the knuckle pin axis (A) relative to the coupler head body (10) between a coupled position and an uncoupled position, and
    • a first lock which is configured to be moved, when the knuckle (11) is in the coupled position, into a locking position in which it prevents rotation of the knuckle (11) about the knuckle pin axis (A) toward the uncoupled position,
  • characterized by the following steps:
    • providing the safety device in the form of a second lock (20), and
    • mounting the second lock (20) on the coupler head (1) in such a manner that, when the knuckle (11) is in the uncoupled position, the second lock (20) is able to:
      • (a) prevent rotation of the knuckle (11) about the knuckle pin axis (A) toward the coupled position, and
      • (b) unlock, when a predetermined force, which acts on the knuckle (11) so as to rotate the knuckle (11) about the knuckle pin axis (A) toward the coupled position, is exceeded, so that the second lock (20) no longer hinders rotation of the knuckle (11) about the knuckle pin axis (A) toward the coupled position.
  • 31. The method of paragraph 30, wherein the safety device may be mounted on the coupler head (1) so as to keep the knuckle (11) in a predetermined relative position with respect to the coupler head body (10) when the knuckle (11) is in the uncoupled position.
  • 32. The method of paragraph 30 or 31, wherein the second lock (20) is arranged such that, when the knuckle (11) is in the uncoupled position and the second lock (20) is in a state in which it prevents rotation of the knuckle (11) about the knuckle pin axis (A) toward the coupled position, the second lock (20) is visible from outside the coupler head (1).
  • 33. The method of any one of paragraphs 30 to 32, wherein the second lock (20) is arranged such that, when the knuckle (11) is in the uncoupled position and the second lock (20) is in a state in which it prevents rotation of the knuckle (11) about the knuckle pin axis (A) toward the coupled position, the second lock (20) is accessible and unlockable from outside the coupler head (1) without a need to disassemble the coupler head (1).
  • 34. The method of any one of paragraphs 30 to 33, wherein the second lock (20) is arranged on a top side of the coupler head (1).
  • 35. The method of any one of paragraphs 30 to 34, wherein at least a part of the second lock (20) is configured to deform when said predetermined force, which acts on the knuckle (11) so as to rotate the knuckle (11) about the knuckle pin axis (A) toward the coupled position, is exceeded.

III.1 Breaking Lock

• • 36. The method of any one of paragraphs 30 to 35, wherein the second lock (20) comprises a locking element (30) which is configured to break when said predetermined force, which acts on the knuckle (11) so as to rotate the knuckle (11) about the knuckle pin axis (A) toward the coupled position, is exceeded.
  • 37. The method of paragraph 36, wherein the locking element (30) comprises a locking pin (21), wherein the method comprises a step of drilling at least one hole (11C; 22, 23) into the coupler head (1), wherein the locking pin (21) is configured to, when the knuckle (11) is in the uncoupled position, engage into the at least one hole (11C; 22, 23) so as to prevent rotation of the knuckle (11) about the knuckle pin axis (A) toward the coupled position, and wherein the locking pin (21) is removable from the at least one hole (11C; 22, 23), without breakage of the locking pin (21), in order to unlock the second lock (20).
  • 38. The method of paragraph 37, wherein the at least one hole (11C; 22, 23) is drilled with an inner diameter of between 4 mm and 8 mm, preferably between 5 mm and 7 mm, more preferably about 6 mm.

III.1.a Locking Pin Extending Through Two Holes

• • 39. The method of paragraph 37 or 38, wherein the step of drilling the at least one hole (22, 23) comprises drilling a first hole (22) in the coupler head body (10) and a second hole (23) in the knuckle (11), wherein the locking pin (21) is configured to, when the knuckle (11) is in the uncoupled position, simultaneously engage into both the first hole (22) and the second hole (23).
  • 40. The method of paragraph 39, comprising a step of fixedly connecting a resilient safety element (24), which provides a resilient force, to one of the coupler head (1) and knuckle (11) in such a manner that, when the knuckle (11) is in the uncoupled position, the resilient safety element (24) is able to:
    • (a) engage with the locking pin (21) so as to prevent unintentional removal of the locking pin (21) from the first and second hole (22, 23), and
    • (b) be disengaged from the locking pin (21) by acting on the resilient safety element (24) against the resilient force so as to allow removing the locking pin (21) from the first and second hole (22, 23).
  • 41. The method of paragraph 39 or 40, comprising a step of fixedly connecting a locking pin holder (25) to the coupler head body (10), knuckle (11) or knuckle pin (12), wherein the locking pin holder (25) is configured to hold the locking pin (21) when the locking pin (21) is in a state removed from the first and second hole (22, 23).
  • 42. The method of any one of paragraphs 39 to 41, comprising the steps of:
    • providing a safety cable (25A) and
    • connecting the locking pin (21) to the coupler head body (10), knuckle pin (12) or knuckle (11) by means of the safety cable (25A),
    • wherein the safety cable (25A) is provided with a sufficient length which allows the locking pin (21), while being connected to the coupler head body (10), knuckle pin (12) or knuckle (11) by means of the safety cable (25A), to engage into the first and second hole (22, 23) and to be held in the locking pin holder (25).

III.1.b Locking Pin Connected to Plunger

• • 43. The method of paragraph 37 or 38, wherein the locking element (30) comprises a plunger (26) to which the locking pin (21) is connected, wherein the method comprises the steps of:
    • detachably connecting the plunger (26) to one of the knuckle (11) and coupler head body (10) and
    • drilling the at least one hole (11C) in the respective other one of the knuckle (11) and coupler head body (10),
    • wherein the arrangement is made such that removal of the locking pin (21) from the at least one hole (11C) without breakage of the locking element (30) requires detaching the plunger (26) from the knuckle (11) or coupler head body (10), respectively.
  • 44. The method of paragraph 43, wherein the locking pin (21) has a weakened portion (21A) configured to break when said predetermined force, which acts on the knuckle (11) so as to rotate the knuckle (11) about the knuckle pin axis (A) toward the coupled position, is exceeded, wherein the arrangement is made such that, when the locking pin (21) engages into the at least one hole (11C), the weakened portion (21A) is located outside the at least one hole (11C) between the plunger (26) and the hole.
  • 45. The method of paragraph 43 or 44, further comprising the step of providing an elastomeric or rubber sleeve (28) on an outer surface of the locking pin (21) or an inner surface of the at least one hole (11C) such that the elastomeric or rubber sleeve (28) is arranged between an outer surface of the locking pin (21) and an inner surface of the at least one hole (11C) when the locking pin (21) engages into the at least one hole (11C).
  • 46. The method of any one of paragraphs 43 to 45, wherein the at least one hole (11C) is a flag hole of the knuckle (11).

III.2. Resilient Lock

• • 47. The method of paragraph 35, wherein the second lock (20) comprises a resilient element (29) and a locking element (30), wherein the method comprises the steps of:
    • arranging the resilient element (29) such that, when the knuckle (11) is in the uncoupled position, a resilient force of the resilient element (29) urges the locking element (30) into a locking position in which the locking element (30) prevents rotation of the knuckle (11) about the knuckle pin axis (A), and
    • arranging the locking element (30) such that it moves, when said predetermined force acting on the knuckle (11) so as to rotate the knuckle (11) about the knuckle pin axis (A) toward the coupled position is exceeded, out of the locking position against the resilient force of the resilient element (29).
  • 48. The method of paragraph 47, comprising the step of attaching the resilient element (29) of the second lock (20) to one of the coupler head body (10) or knuckle pin (12), on the one hand, and knuckle (11), on the other hand, such that the locking element (30) of the second lock (20) is able to engage, when the knuckle (11) is in the uncoupled position, with the respective other one of the coupler head body (10) or knuckle pin (12), on the one hand, and knuckle (11), on the other hand.
  • 49. The method of paragraph 47 or 48, wherein the step of arranging the locking element (30) is such that the locking element (30) is able to engage a depression or hole (11C) when the knuckle (11) is in the uncoupled position.
  • 50. The method of paragraph 49, wherein the hole (11C) is a flag hole of the knuckle (11).
  • 51. The method of paragraph 49 or 50, wherein the locking element (30) has a sloped surface (30A) by which it engages the hole (11C) or depression when the knuckle (11) is in the uncoupled position.

III.2.a Leaf Spring

• • 52. The method of any one of paragraphs 47 to 51, wherein the resilient element (29) is provided as a leaf spring.
  • 53. The method of paragraph 52, wherein the locking element (30) is provided so as to form an integral part of the leaf spring.
    III.2.b Plunger with Compression Spring
  • 54. The method of any one of paragraphs 47 to 51, wherein the resilient element (29) comprises a compression spring arranged on a plunger (26).
  • 55. The method of paragraph 54, wherein the arrangement of the resilient element (29) is made such that the compression spring is able to urge the locking element (30) into the locking position.

IV. Coupler Assembly

• • 56. A coupler assembly for a car of a multi-car rail vehicle, comprising a coupler head (1) according to any one of paragraphs 1 to 29 and further comprising energy absorption means configured to absorb energy when the coupler head (1) collides with a corresponding coupler head (1) of another car of the multi-car vehicle.

Claims

1. A coupler head for a coupler assembly of a multi-car rail vehicle, comprising:

a coupler head body, a knuckle configured for cooperating with a corresponding knuckle of another coupler head, and a knuckle pin having a knuckle pin axis, wherein the knuckle pin is mounted to the coupler head body and the knuckle is mounted to the knuckle pin so that the knuckle is rotatable about the knuckle pin axis relative to the coupler head body between a coupled position and an uncoupled position,

a first lock which is configured to be moved, when the knuckle is in the coupled position, into a locking position in which it prevents rotation of the knuckle about the knuckle pin axis toward the uncoupled position, and

a second lock which is configured to prevent, when the knuckle is in the uncoupled position, rotation of the knuckle about the knuckle pin axis toward the coupled position, wherein the second lock is further configured to unlock when a predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded, so that the second lock no longer hinders rotation of the knuckle about the knuckle pin axis (A) toward the coupled position.

2. The coupler head of claim 1, wherein the second lock is configured to connect the knuckle to the coupler head body and keep the knuckle in a predetermined relative position with respect to the coupler head body when the knuckle is in the uncoupled position.

3. The coupler head of claim 1, wherein, when the knuckle is in the uncoupled position and the second lock is in a state in which it prevents rotation of the knuckle about the knuckle pin axis toward the coupled position, the second lock is visible from outside the coupler head.

4. The coupler head of claim 1, wherein, when the knuckle is in the uncoupled position and the second lock is in a state in which it prevents rotation of the knuckle about the knuckle pin axis toward the coupled position, the second lock is accessible and unlockable from outside the coupler head without a need to disassemble the coupler head.

5. The coupler head of claim 1, wherein the second lock is arranged on a top side of the coupler head.

6. The coupler head of claim 1, wherein at least a part of the second lock is configured to deform when said predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded.

7. The coupler head of claim 1, wherein the second lock comprises a locking element which is configured to break when said predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded.

8. The coupler head of claim 7, wherein the locking element comprises at least one of:

a breaking portion which, when said predetermined force acting on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position is exceeded, is configured to break, wherein at least said breaking portion of the locking element is made of bronze or stiff polymer, and

a locking pin which is configured to, when the knuckle is in the uncoupled position, engage into at least one hole, thereby preventing the rotation of the knuckle about the knuckle pin axis toward the coupled position, wherein the locking pin is removable from the at least one hole without breakage of the locking pin, in order to unlock the second lock.

9. The coupler head of claim 8, wherein the locking element comprises a locking pin which is configured to, when the knuckle is in the uncoupled position, engage into at least one hole, wherein the at least one hole comprises a first hole provided in the coupler head body and a second hole provided in the knuckle, and wherein the locking pin is configured to, when the knuckle is in the uncoupled position, simultaneously engage into both the first hole and the second hole and break when said predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis (A) toward the coupled position, is exceeded.

10. The coupler head of claim 9, wherein the coupler head comprises at least one of:

the locking pin having a weakened portion configured to break when said predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis (A) toward the coupled position, is exceeded, wherein, when the locking pin engages into the first and second hole, the weakened portion is located between the first hole and the second hole,

the second lock further comprising a resilient safety element providing a resilient force, wherein the resilient safety element is fixedly connected to one of the coupler head body and knuckle and configured to engage, when the knuckle is in the uncoupled position, with the locking pin so as to prevent removal of the locking pin from the first and second hole, and wherein the resilient safety element is further configured to be disengaged from the locking pin by acting on the resilient safety element against the resilient force so as to allow removing the locking pin from the first and second hole, or

a locking pin holder provided on the coupler head body, knuckle or knuckle pin, wherein the locking pin holder is configured to hold the locking pin when the locking pin is in a state removed from the first and second hole.

11. The coupler head of claim 7, wherein the locking element further comprises a plunger to which the locking pin is connected, wherein the plunger is detachably connected to one of the knuckle and coupler head body and the at least one hole is arranged on the respective other one of the knuckle and coupler head body, wherein removal of the locking pin from the at least one hole without breakage of the locking element requires detaching the plunger from the knuckle or coupler head body, respectively.

12. The coupler head of claim 11, wherein the coupler head comprises at least one of:

the plunger configured to, once detached from the knuckle or coupler head body, be reconnected thereto, in a manner which does not hinder rotation of the knuckle about the knuckle pin axis toward the coupled position, by turning the plunger about 180° and reattaching it at connection points which are identical to connection points prior to the detachment,

the locking pin having a weakened portion configured to break when said predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis (A) toward the coupled position, is exceeded, wherein, when the locking pin engages into the at least one hole, the weakened portion is located outside the at least one hole between the plunger and the at least one hole,

an elastomeric or rubber sleeve provided between an outer surface of the locking pin and an inner surface of the at least one hole when the locking pin engages into the at least one hole, or

the at least one hole being a flag hole of the knuckle.

13. The coupler head of claim 1, wherein the second lock comprises a resilient element and a locking element, wherein the resilient element is arranged to provide, when the knuckle is in the uncoupled position, a resilient force urging the locking element into a locking position in which the locking element prevents the rotation of the knuckle about the knuckle pin axis, and wherein the locking element is arranged to move, when said predetermined force acting on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position is exceeded, out of the locking position against the resilient force of the resilient element.

14. The coupler head of claim 13, wherein the coupler head comprises at least one of:

the resilient element of the second lock attached to one of (a) the coupler head body or the knuckle pin, or (b) the knuckle, and wherein the locking element of the second lock is configured to engage, when the knuckle is in the uncoupled position, with the respective other one of (a) the coupler head body or the knuckle pin, or (b) the knuckle,

the locking element engaging a depression or hole when the knuckle is in the uncoupled position, or

the locking element having a sloped surface by which it engages the hole or depression when the knuckle is in the uncoupled position.

15. The coupler head of claim 13, wherein the resilient element is a leaf spring, wherein the locking element forms an integral part of the leaf spring.

16. The coupler head of claim 13, wherein the resilient element comprises a compression spring arranged on a plunger, wherein the resilient element is configured to urge the locking element into the locking position.

17. A method of retrofitting a coupler head of a coupler assembly of a multi-car rail vehicle with a safety device, wherein the coupler head comprises:

a coupler head body, a knuckle configured for cooperating with a corresponding knuckle of another coupler head, and a knuckle pin having a knuckle pin axis, wherein the knuckle pin is mounted to the coupler head body and the knuckle is mounted to the knuckle pin so that the knuckle is rotatable about the knuckle pin axis relative to the coupler head body between a coupled position and an uncoupled position, and

a first lock which is configured to be moved, when the knuckle is in the coupled position, into a locking position in which it prevents rotation of the knuckle about the knuckle pin axis toward the uncoupled position,

the method comprising: providing the safety device in the form of a second lock, and mounting the second lock on the coupler head in such a manner that, when the knuckle is in the uncoupled position, the second lock is able to: (a) prevent rotation of the knuckle about the knuckle pin axis toward the coupled position, and (b) unlock, when a predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded, so that the second lock no longer hinders rotation of the knuckle about the knuckle pin axis toward the coupled position.

18. The method of claim 17, further comprising at least one of:

the safety device is mounted on the coupler head so as to keep the knuckle in a predetermined relative position with respect to the coupler head body when the knuckle is in the uncoupled position,

the second lock is arranged such that, when the knuckle is in the uncoupled position and the second lock is in a state in which it prevents rotation of the knuckle about the knuckle pin axis toward the coupled position, the second lock is visible from outside the coupler head,

the second lock is arranged such that, when the knuckle is in the uncoupled position and the second lock is in a state in which it prevents rotation of the knuckle about the knuckle pin axis toward the coupled position, the second lock is accessible and unlockable from outside the coupler head without a need to disassemble the coupler head,

the second lock is arranged on a top side of the coupler head, or

at least a part of the second lock is configured to deform when said predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded.

19. A coupler assembly for a car of a multi-car rail vehicle, comprising:

a coupler head, comprising: a coupler head body, a knuckle configured for cooperating with a corresponding knuckle of another coupler head, and a knuckle pin having a knuckle pin axis, wherein the knuckle pin is mounted to the coupler head body and the knuckle is mounted to the knuckle pin so that the knuckle is rotatable about the knuckle pin axis relative to the coupler head body between a coupled position and an uncoupled position, a first lock which is configured to be moved, when the knuckle is in the coupled position, into a locking position in which it prevents rotation of the knuckle about the knuckle pin axis (A) toward the uncoupled position, and a second lock which is configured to prevent, when the knuckle is in the uncoupled position, rotation of the knuckle about the knuckle pin axis toward the coupled position, wherein the second lock is further configured to unlock when a predetermined force, which acts on the knuckle so as to rotate the knuckle about the knuckle pin axis toward the coupled position, is exceeded, so that the second lock no longer hinders rotation of the knuckle about the knuckle pin axis toward the coupled position; and

energy absorption means configured to absorb energy when the coupler head collides with a corresponding coupler head of another car of the multi-car vehicle.