WO2011162671A1

WO2011162671A1 - Shock-absorbing coupling arrangement

Info

Publication number: WO2011162671A1
Application number: PCT/SE2011/050702
Authority: WO
Inventors: Anders Svedbo
Original assignee: Soldian Limited
Priority date: 2010-06-23
Filing date: 2011-06-08
Publication date: 2011-12-29
Also published as: SE534925C2; SE1050676A1

Abstract

A coupling arrangement is shown, comprising a drawbar (1) and a coupler head (2), which in a rear end is attached to the drawbar and extends in the longitudinal direction of the same to a front end that is arranged to carry a front plate (4) having a coupling interface between coupled rail vehicles, which coupler head furthermore houses components (7-10) of a mechanical coupling (6) effective for automatic coupling to the corresponding coupling components of a connecting coupling arrangement. The drawbar extends elongated into the coupler head and is in a traction force-transmitting engagement with the mechanical coupling (6), and said extension (20) of the drawbar is arranged to be subjected to a predetermined deformation while absorbing energy from a deforming compressive force applied in the longitudinal direction in addition to which the extension has juxtapositionly running beams (22, 23) arranged to, upon length reduction of the extension (20), be deformed primarily in the horizontal direction.

Description

TITLE

Shock-absorbing coupling arrangement

TECHNICAL FIELD OF THE INVENTION

The invention concerns a coupling arrangement for rail vehicles comprising a drawbar and a coupler head, which in a rear end is attached to the drawbar and extends in the longitudinal direction of the same to a front end, which is arranged to carry a front plate, which coupler head furthermore houses components of a mechanical coupling effective for automatic coupling to the corresponding coupling components of a connecting coupling arrangement. More precisely, the invention relates to a coupling arrangement of this type that, by a predetermined course of deformation, is arranged to dissipate energy from a deforming compressive force that is applied to the coupling arrangement in the longitudinal direction thereof. BACKGROUND AND PRIOR ART

Shock-absorbing devices in rail vehicles are previously known. Known devices may, for instance, be made as deformable brackets for the mounting of buffers on a car chassis, see, e.g., DE 10 2004 045 737 Al, WO 00/051 19 Al , US 2009/0000506 Al .

Different solutions are also previously known for the absorption of energy in a coupling arrangement between rail vehicles. These solutions comprise, for example, shock-absorbing elastic damping devices mounted in the coupling arrangement, but also devices that are arranged to be plastically deformed in the event of a collision, in the conversion of at least a portion of the generated force into kinetic energy and heat. To these latter devices, expanding or compressible deformation tubes typically belong, which may be included in the fixing of the coupling arrangement to a car chassis or which are integrated parts of the drawbar. As an example of the latter, EP 1 312 527 Al or EP 1 663 755 B l could be pointed out.

The coupler head of an automatic coupler, which in a surrounding housing accommodates the mechanical coupling components necessary for coupling for automatic engagement with a meeting coupler, is usually made of castings and lacks typically shock-absorbing measures. A coupler head housing made of weldable forged steel for a central buffer coupling is, however, previously known from DE 1 124 535. This coupler head housing is dimensioned to resist occurring normal traction and thrust forces, but lacks measures for a controlled shock- absorbing deformation. BRIEF SUMMARY OF THE INVENTION

The invention aims at generally increasing the capability of a coupling arrangement of absorbing energy, in particular energy arising from forces generated in a collision, and thereby providing an increased protection against deformation of the car chassis.

Therefore, an object of the invention is to provide a coupling arrangement for the automatic coupling of rail vehicles, which coupling arrangement is arranged to be deformed in a predetermined way while absorbing energy.

Another object of the invention is to provide a coupling arrangement that is arranged to remain in the coupled state, and in particular in a traction force- transmitting state, also after a predetermined deformation of the coupling arrangement.

In brief, a coupling arrangement is provided of the type indicated by way of introduction, in which the drawbar extends elongated into the coupler head and is in a traction force-transmitting engagement with the mechanical coupling. For an increased capability of the coupling arrangement of absorbing energy from a deforming compressive force applied in the longitudinal direction, said extension of the drawbar is arranged to be subjected to a predetermined deformation in the form of a length reduction. In a preferred embodiment, the mechanical coupling is supported in the extension of the drawbar. By the fact that the coupling in this way is carried along in the deformation motion of the coupler head and extension element, the risk of breaking forces being generated between the coupling and the coupling arrangement in the course of deformation is reduced.

The displaceable bearing of the coupling can meritoriously be realised by a trunnion included in the mechanical coupling being arranged to extend through a

longitudinal groove in the extension of the drawbar, which groove is limited by two juxtapositionly running beams.

In an advantageous embodiment, said trunnion extends through a groove limited by two parallel side beams that converge in front of the axis. Upon compression and length reduction of the extension, said juxtapositionly running beams are arranged to be deformed primarily in the horizontal direction, by which here it is intended that their deformation motion has a dominating horizontal direction component, and, where appropriate, an insignificant and negligible vertical direction component.

In a preferred embodiment, the side beams are arranged and predetermined to bend outward in opposite lateral directions. The controlled deformation of the side beams of the extension may be provided by the side beams already from the beginning being given a slightly outwardly bent shape, or, for instance, by forming them with a rectangular cross-section having shorter horizontal sides and longer vertical sides. In a preferred embodiment, said side beams are compression-moulded parts of a separate element connected with the drawbar and made from steel, in which notches for a controlled deformation are provided in compression-moulding.

In a preferred embodiment of the invention, the coupler head is connected with the drawbar by means of a collar surrounding the drawbar in front of a shoulder formed on the drawbar, and is displaceable rearward on the drawbar in the longitudinal direction against the force of a radial expansion of said collar caused by the shoulder.

The shoulder has suitably a conical front against which the collar is forced to expand upon triggering of the rectilinear motion of the coupler head on the drawbar. By selection of material and material thickness of the collar, and by adaptation of the cone angle and radial protrusion from the drawbar of the shoulder, the threshold value of the force required to trigger the motion of the coupler head on the drawbar and the force required for the radial expansion of the collar can be determined, by which the level of the shock-absorbing capability of the coupling arrangement can be influenced.

For an axial fixation of the coupler head on the drawbar in normal operating conditions, shearable elements or shear pins, known per se, can be utilized for interconnection of the drawbar and the coupler head. In order to allow shock absorption by a controlled deformation to an even higher extent, it is taught, in another preferred embodiment, that the housing of the coupler head has at least one notch for a predetermined axial compression of the coupler head housing. In the shown embodiment example, the coupler head housing comprises two opposite sides, an upper part and a bottom, respectively, notches for the folding of the coupler head housing being made at least in the sides of the coupler head housing, but preferably also in the upper part and bottom thereof.

By these measures, three deformation steps are provided, which may be combined in various ways in a coupling arrangement having the ability to absorb energy:

• by the displacement of the coupler head inward on the drawbar against the force of a forced radial expansion of the connection of the coupler head with the drawbar, and/ or

• by the predetermined compression and folding of the coupler head housing according to notches made on the coupler head housing, and / or

• by the deformation of an element arranged internally in the coupler head and that is connected with the drawbar and forming an extension of the same, which extension extends into the coupler head.

In a particularly preferred combination comprising at least two of the deformation steps, the extension of the drawbar extends up to or quite close to the front plate carried in the front end of the coupler head, whereby the same is brought to deformation by the front plate as a result of the coupler head housing being displaceably arranged on the drawbar, and/or as a result of the coupler head housing being arranged to be compressed axially by folding.

It will be appreciated by a person skilled in the art that a complete quenching or absorption of the energy that is generated in, for instance, a collision, only can be expected in connection with forces up to a certain magnitude, while forces exceeding this magnitude result in a no longer predictable deformation. The object of the invention is, however, still achieved, because the energy that is dissipated during the controllable deformation of the coupler head implies a corresponding reduction of the initial force. In combination with other shock-absorbing devices, known per se, in the coupler, the invention implies that more energy can be absorbed before the car chassis is affected by a deforming force.

The coupler head is preferably made from steel, the elasticity and ability of the steel to be plastically deformed when subjected to loads above its yield point being utilized to convert a deforming compressive force into kinetic energy and heat. In particular, it is taught that at least said collar, and preferably the coupler head housing in its entirety, is made from a high-strength steel, such as an advanced high-strength steel or a steel having extra high or ultra high strength, whereby the required strength to resist normal traction or thrusts occurring during operation can be provided also in a coupler head of comparatively low weight.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be elucidated below by embodiment examples and reference being made to the accompanying schematic drawings, of which

Fig. 1 shows a partially sectioned view from above of a coupling arrangement according to the invention;

Fig. 2 shows the coupling arrangement in Fig. 1 in a partially sectioned side view;

Fig. 3 shows the coupling arrangement in Figs. 1 and 2 in a partially deformed state;

Fig. 4 shows the coupling arrangement in Figs. 1-3 in an additionally deformed state, in a side view;

Fig. 5 shows the coupling arrangement in Fig. 4 in a view from above, and

Fig. 6 is a load-displacement diagram that schematically illustrates a shock- absorbing course of deformation.

DETAILED DESCRIPTION OF EMBODIMENT EXAMPLES

It should be emphasized that the drawing figures are schematic and only suited to elucidate the general idea of the invention such as the same is seen in the written description and in the connecting claims. Therefore, the invention should not be considered limited to shown dimensions, geometries or to the embodiment of design details in the embodiment examples, because these have to be considered by a person skilled in the art in each individual application of the invention. In particular, it should be noted that material thicknesses and other dimensions may be over dimensioned and the constructive design of details simplified, for reasons of drawing technique.

The drawing figures schematically show a coupling arrangement comprising a drawbar 1, which in its inner end is mountable in a car chassis and in its outer end carries a coupler head 2. The coupler head 2 comprises a coupler head housing 3 and is, in a first and rear end, attachable to the drawbar 1 , and in a second and front end arranged to carry a front plate 4, typically comprising a guide cone 5 for the alignment of the coupler heads upon coupling to a corresponding coupling arrangement. In the drawings, the guide cone of the connecting coupling

arrangement is illustrated by a dash-dotted line. Components included in a mechanical coupling 6, such as a central plate 7 and a coupling link 8, are housed in the coupler head housing and rotatably carried on a pivot or shaft 9, which in turn is mounted in bearings 10 mounted in the coupler head. Devices for the locking/unlocking of the coupling mechanism are for the sake of simplicity excluded from the drawing figures, as well as devices for the connection of electricity and pneumatics /hydraulics, which usually are carried on the outside of the coupler head. The coupler head housing 3 has a box-shaped structure and consists of an upper part 1 1 , a bottom 12, and two opposite sides 13 and 14, respectively. The upper part and the bottom, as well as the two sides, may suitably be mutually identically shaped with the exception of externally or internally arranged attachments and seats for the mounting of additional equipment. The parts of the coupler head housing consist, as previously mentioned, preferably of steel and are suitably assembled by welding and/ or screw fitting.

As is seen in Figs. 1, 3 and 5, the coupler head housing is generally shaped as a funnel the sides of which are bent in such a way that a predetermined folding takes place upon axial compression of the coupler head housing, as a result of a deforming compressive force FB acting in the longitudinal direction of the coupling arrangement (see Fig. 3). Figs. 2 and 4 illustrate how the upper part and bottom of the coupler head housing can be correspondingly made for a predetermined folding of the same.

In the connection area between the coupler head and the drawbar, the coupler head has, in its rear end, a collar 15, which surrounds the drawbar in front of a shoulder 16 arranged on the drawbar. The shoulder 16 protrudes radially from the drawbar and has an oblique front surface 17 facing the collar. The front surface 17 forms a conical ring over which the collar 15 is forced to expand radially upon the rectilinear displacement of the coupler head rearward on the drawbar. A stop (not shown) fixedly arranged on the drawbar may be arranged behind the shoulder 17 to limit the possible rectilinear motion. Alternatively, as is illustrated in the drawings, the displacement of the coupler head inward on the drawbar may be limited by the collar being stopped against a flange coupling 18 by which the coupling

arrangement is mountable in a car chassis. The reference numeral 19 in Fig. 1 designates a seat in the drawbar intended for the receipt of a shear pin (not shown), which, where appropriate, has the purpose of guaranteeing the axial fixation of the coupler head on the drawbar in normal operating conditions.

An extension 20 extends forward in the longitudinal direction from the drawbar 1 and has a groove 21 having an axial extension that is limited by two side beams 22 and 23 running in parallel, which in the front ends thereof converge in front of the shaft 9 included in the coupling. The shaft 9 extends through the groove 21 and is, via the extension 20, in a traction force-transmitting engagement with the drawbar 1. In the coupling arrangement of the embodiment example, the extension consists of an upper part 20' running in the gap between the coupling 6 and the upper part 1 1 of the coupler head housing, and a corresponding lower part 20" that runs in the gap between the coupling 6 and the bottom 12 of the coupler head housing. In this embodiment, the parts 20' and 20" of the extension form a respective guiding of the upper part and bottom of the coupler head housing in the course of the compression/ folding of the coupler head housing, and particularly prevent these from folding inward in a way unfavourable for the function of the coupling. In particular, the extension 20, 20' provides a support for the upper part and bottom of the coupler head housing in the area of the bearings 10 of the shaft, whereby the shaft 9 and the coupling 6 can be carried along in the axial compression of the coupler head housing and displaced rearward in the groove 21 , but in other respects essentially unaffected by the course of deformation.

Fig. 3 shows the coupling arrangement in a state in which the compression of the coupler head housing by folding has resulted in the front plate 4 being brought in contact with the front tip of the extension 20. The same state may alternatively be achieved only by the rectilinear displacement of the coupler head rearward on the drawbar, or by a combination of the displacement of the coupler head and the folding of the coupler head housing. How these two deformation steps are utilized or combined may be a dimensioning question by a person skilled in the art, as well as the selection of order in case that the coupling arrangement is formed for both deformation steps.

From the state shown in Fig. 3, continued compression of the coupler head housing, and/ or a displacement of the coupler head housing rearward on the drawbar, results in a shock- absorbing deformation of the extension 20. Said deformation may be regarded as a third substep of the total shock-absorbing course of deformation. The side beams 22 and 23 of the extension are for the purpose formed to be deformed primarily in a horizontal plane, in the way discussed above. In a meritorious and preferred embodiment, the side beams 22, 23 are arranged to be upset outward in opposite lateral directions, away from the shaft 9 running through the groove 21, as shown in Figs. 4 and 5. A controlled deformation of the side beams 22, 23 may, as discussed above, be provided in various ways. The side beams 22, 23 may advantageously be included as compression-moulded parts of a separate steel or high-strength steel extension element 20 connected with the drawbar and designed with notches for a controlled deformation.

In Fig. 5, there is illustrated the deformation distance S that is available in the coupling arrangement of the embodiment example without the mechanical coupling 6 being essentially affected in a controllable course of deformation. By the corresponding course of deformation in the connected coupling arrangement, here shown by a dash-dotted line, accordingly a total shock-absorbing deformation distance of S + S is provided. In the deformed state shown in Figs. 4 and 5, the extension 20 still serves as a traction force-transmitting link between coupled cars also if the coupler head no longer, as a result of the deformation of the collar 15, is axially fixed on the drawbar in the towing direction.

It should be appreciated that the drawing figures contain a simplified account of the design of the coupling arrangement, and that design details predictable by a person skilled in the art are omitted for reasons of clarity. A detail that deserves to be mentioned in this context is that the coupler head, if required, may comprise support members, such as stays or support elbows, which, where appropriate, may be fixedly arranged on the coupler head housing and effective to impart increased stiffness to the same in its compressed state. Moreover, a blocking member 24 (see Fig. 5) may be mentioned, which advantageously is dismountable from the outside of the coupler head, and which, by the folding of the coupler head housing, is arranged to be brought into an active state to prevent the rotation of the central plate into an unlocking state. An example of a shock- absorbing course of deformation may be described according to the following (see also Fig. 6): Upon application of a deformed force FB, the coupler head housing is initially subjected to an elastic deformation until the force reaches the threshold value YP at which a permanent deformation commences. The shock-absorbing capability of the coupling arrangement rises to a force peak at which the predetermined folding of the coupler head housing commences. The compression of the coupler head housing is retarded upon the impact of the front plate against the drawbar extension, the shock-absorbing capability rising to a second threshold value represented by the initial deformation resistance of the drawbar extension and, where appropriate, of the collar, possibly with the addition of the ultimate strength value of shear pins in the connection between the coupler head and the drawbar. The shock-absorbing capability of the coupling arrangement rises further to a force peak at which the axial compression of the drawbar extension and the radial expansion of the collar commence, parallel to or at least overlapping each other, after which the deformation resistance falls but from a higher level. Upon change to tension load on the coupling arrangement, certain elasticity typically commences in the coupling, before a traction force-transmitting engagement is recreated between the drawbar extension 20 and the shaft 9 of the coupling.

Another preferred embodiment involves that the coupler head housing is made with an inherent stiffness and resistance against folding and axial compression that exceeds the threshold value of the rectilinear displacement of the coupler head rearward on the drawbar. According to this preferred embodiment, the first step of the course of deformation consists accordingly of the displacement of the coupler head on the drawbar, while the axial compression of the coupler head housing and the axial compression of the drawbar extension take place in parallel, entirely or partly overlapping each other, in a subsequent deformation step. Of course, it is also feasible that the drawbar extension 20 already initially contacts the front plate and that all substeps of the predetermined deformation of the coupling

arrangement are triggered essentially simultaneously.

It should in conclusion be emphasized that the course of deformation described above only is an example of a possible and advantageous combination of shown shock-absorbing measures in a coupling arrangement according to the invention. It will be appreciated that each one of the shock-absorbing measures gives a contribution to the total capability of the coupling arrangement of absorbing energy, and another order among the substeps of the course of deformation is feasible.

Claims

1. Coupling arrangement comprising a drawbar ( 1) and a coupler head (2) , which in a rear end is attached to the drawbar and extends in the longitudinal direction of the same to a front end that is arranged to carry a front plate (4) , which coupler head furthermore houses components (7-10) of a mechanical coupling (6) effective for automatic coupling to the corresponding coupling components of a connecting coupling arrangement, characterized in that the drawbar extends elongated into the coupler head and is in a traction force-transmitting engagement with the mechanical coupling (6) , and in that said extension (20) of the drawbar is arranged to be subjected to a predetermined deformation while absorbing energy from a deforming compressive force applied in the longitudinal direction, in addition to which the extension (20) has juxtapositionly running beams (22 , 23) arranged to, upon length reduction of the extension (20) , be deformed primarily in the horizontal direction.

2. Coupling arrangement according to claim 1 , wherein the mechanical coupling (6) is displaceably supported in the longitudinal direction in the extension (20) of the drawbar.

3. Coupling arrangement according to claim 2, wherein a shaft (9) included in the mechanical coupling (6) extends through a longitudinal groove (2 1) in the extension of the drawbar, which groove is limited by two parallel side beams (22 , 23) that converge in front of the axis (9) and are arranged to bend outward in opposite lateral directions.

4. Coupling arrangement according to claim 3, wherein the side beams (22, 23) are compression-moulded parts of a separate element connected with the drawbar ( 1 ) .

5. Coupling arrangement according to any one of claims 1-4, wherein the extension (20) of the drawbar extends into a coupler head housing (3) comprising two opposite sides ( 13, 14) , an upper part ( 1 1) and a bottom ( 12) , respectively, and the drawbar extension comprises an upper extension (20 which is arranged to extend in the gap between the coupling (6) and the upper part ( 1 1) of the coupler head housing, and a corresponding lower extension (20") arranged to extend in the gap between the coupling (6) and the bottom ( 12) of the coupler head housing.

6. Coupling arrangement according to claim 5, wherein the extension (20) of the drawbar extends up to or quite close to the front plate (4) carried in the front end of the coupler head, and by the front plate is brought to said deformation as a result of the coupler head (3) being displaceably arranged on the drawbar, and/or as a result of the coupler head housing being arranged to be compressed axially and for the purpose having at least one notch for a predetermined folding of the coupler head housing.

7. Coupling arrangement according to claim 6, wherein notches for the folding of the coupler head housing are made at least in the sides of the coupler head housing, and preferably also in the upper part and bottom thereof.

8. Coupling arrangement according to any one of claims 6-7, wherein the coupler head is connected with the drawbar by means of a collar (15) surrounding the drawbar in front of a shoulder (16) formed on the same, and is displaceable on the drawbar in the longitudinal direction against the force of a radial expansion of said collar caused by the shoulder.

9. Coupling arrangement according to any one of claims 6-8, furthermore

comprising a member (24) that, by the compression of the coupler head housing, is arranged to be brought into a position in which the member prevents the rotation of a central plate (7) included in the mechanical coupling (6) into an unlocking state.