EP2612404B1

EP2612404B1 - Connector with spreader for twisted wires

Info

Publication number: EP2612404B1
Application number: EP11822226.4A
Authority: EP
Inventors: Lars MÖTTÖNEN
Original assignee: EGO INTERNATIONAL BV
Current assignee: EGO INTERNATIONAL BV
Priority date: 2010-09-03
Filing date: 2011-09-01
Publication date: 2016-06-15
Anticipated expiration: 2031-09-01
Also published as: WO2012030291A1; SE535946C2; EP2612404A1; EP2612404A4; SE1050906A1

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates in a first aspect to a connector for termination of at least two incoming and pair-wise twisted wires. In a second aspect the present invention relates to a signal transmission arrangement in a train coupler.

BACKGROUND OF THE INVENTION

In modern vehicles there exists a large demand for fast signal transmission between the subsystems of the vehicle. These signals can be of both analogue and digital type. The signal is transmitted via optical signals, radio waves or as electric signals in an electrical conductor. For analog and digital signals that will be transmitted in a vehicle, is it advisable to choose a signal transmission system that is both simple and well-dimensioned for the desired bandwidth.
Usually a signal transmission system based on some type of electrical signal is selected. The electrical signal can be of either digital or analog type. If a large bandwidth and a large signal/noise ratio are desired, preferably an electrical conductor of either coaxial type or twisted type is selected.
The twisted cable type comprises pair-wise twisted wires and a cable may comprise one or more pairs of twisted wires. These pairs are surrounded by an outer cover of either plastic or rubber. In order to further enhance the cable's immunity to interference it can be equipped with an electrical conductive covering usually designated "shield".
Cables comprising twisted pairs of wires are particularly suitable for low noise transmission of analog signals when high immunity to interference is desirable, such as transmission of signals from a sensor.
In normal on-road vehicles such as cars and trucks are the cables usually connected directly to the subsystems of the vehicle by means of standard connectors. The connectors must be appropriate for use in relatively sheltered environments, and must perform well for a relatively small number of connections and disconnections. The connectors are usually disconnected only for servicing and repair of the vehicle.
If the signal transmission takes place in a train comprising multiple rail vehicles such as locomotives and cars, quite different demands on the connectors that connect the signals between the different vehicles in the train will arise.
The signal-related connection in a rail-bound train is generally performed by using a special terminal block, where the various connectors are arranged for power supply and signal transmission, for example. The terminal is divided into rows and columns with fasteners for the connectors arranged with a predetermined spacing. The spacing is dimensioned in order for the connectors to be robust enough to allow a secure connection. The robustness of the connectors implies that the terminal block becomes dimensionally rather large compared to the cables for the actual signal transmission.
These connectors should of course be separable to allow automatic coupling and decoupling of the rail vehicles in the train. The connectors must also withstand harsh conditions due to the operating environment in the form of moisture, dust, dirt, cold, heat and vibrations.
Traditionally at joining and termination of cables comprising twisted pairs of wires the twisted pair is split apart, and the twisted structure is interrupted near the joint/termination. The wires of the pair are distributed to individual connectors which in turn are secured in said terminal block or connected to a corresponding complementary connector. This interrupt in the twisted structure will impair the immunity against interference, which typically manifests itself in problems with crosstalk that occurs or increases. The problem becomes even larger if the cable is arranged with a shield that must be interrupted at the termination in order for the twisted pair to be connected to the terminal block.
This problem has been solved in such a way that a connector with a conducting housing is used and to which the shield is connected. The wires of the twisted pair are split apart a distance corresponding to the necessary distance needed for stripping and distribution in the connector. The connector has a body arranged to be surrounded by a sleeve. The body usually comprises contact elements to which the individual wires of the pair is distributed and connected. This solution causes a problem with the arrangement of the wires in the connector, due to the fact that the individual wires are not twisted in the connector and not anchored, which causes a spread in cross-talk characteristics and varying contact impedance between different connectors of the same type. A large spread in the contact impedance causes the impedance match of the cable to be less than optimal, which in turn causes bandwidth degradation of the signal transmission, thereby causing a lower transmission speed.
A connector is disclosed in US4693537 that solves at least some of the above identified problems. This solution discloses a connector that is separable in two pieces along a parting line. This solution is not viable if a cable with more than one twisted pairs is used. This solution is also not suitable for use in an automatic couple due to the bayonet coupling. This solution also involves bending the cables in the twisted pair in a way that is incompatible with high speed communication.
Another connector is disclosed in US2008/026647 that at least partly solves some of the above outlined problems.

DESCRIPTION OF THE INVENTION

The invention aims to eliminate the problem of varying contact impedance and crosstalk characteristics due to the distribution of the wires in a cable with twisted pair wires in a connector suitable for automatic train couplers.
The object of the invention is attained by means of a connector of the initially defined type that comprises a spreader connectable to a cable terminator, the spreader having contact pins embedded in a dielectric material, the contact pins extending through the spreader and in at least a part of their extension having a radial direction component. The spreader is further separable into at least two parts, the parts having paths arranged for the contact pins.
This spreader causes the twisted wires of the cable to be coupled to the contact pins in the spreader in a controllable and repetitive way, thereby causing a geometrical spreading by means of the spreader. The embedding of the contact pins in a dielectric material causes the technical effect of arresting the contact pins in the spreader, whereby contact impedance becomes constant between different connectors and different events of coupling. As the spreader is separable into at least two parts the possibility to manufacture spreader and connector pins separately is attained. This means that even a single contact pin can be removed and replaced.
According to a preferred embodiment said paths extend at least partially in a distribution plane perpendicular to a longitudinal axis of the spreader, and are angularly equally spaced in the distribution plane.
Thereby the additional advantage that the contact pins becomes easily replaceable and dismountable is attained
The connector comprises a sleeve that extends coaxially with the spreader, the connector having a seat arranged in a forward end thereof, the seat is arranged to receive the spreader.
By forming the seat and spreader with mutual form fit, the spreader can be mounted firmly in the sleeve. The sleeve further extends around the spreader, whereby efficient shielding of the spreader is attained.
According to a preferred embodiment the connector comprises a cable terminator having for each wire an electrical contact element that connects the conductor to a contact pin embedded in the spreader. The cable terminator is further operable for arresting the wires of the cable.
In this way the arresting characteristics of the cable terminator is optimized, whereby the repeatable characteristics of the contact impedance is influenced in a good way.
According to the preferred embodiment, said sleeve is internally dimensioned to radially fix the cable terminator in the sleeve. Hereby, mechanical stability and vibration protection are attained.
Said sleeve preferably comprises a seat arranged to receive a clamping ring insertable in the rear end of the sleeve, the seat comprising a stop for said clamping ring. The clamping ring forms a rear axial stop for the cable terminator in the sleeve.
When the seat for the clamping ring is arranged in the sleeve, the clamping ring will in one direction form an axial stop for all parts of the connector.
The connector comprises a shell arranged to threadingly engage a threaded rear part of the sleeve, the shell comprising a stop that presses against the clamping ring as the shell engages the sleeve for locking the clamping ring in the sleeve.
This means that the sleeve will press the clamping ring and the sleeve together, whereby the clamping ring will press the cable terminator and the spreader together in the sleeve and fixate these relative to the shell.
Said connector preferably comprises a locking washer, which is arranged to be removably mounted on the front end surface of the sleeve, whereby the spreader is arrested in the sleeve.
Said locking washer comprises at least two contact sleeves, which are arranged centered around the contact pins. The contact sleeves can be integrated in the locking washer or alternatively be separate elements that are arrested by said locking washer in a mounted position thereof.
By arranging the connector in this way with removable contact sleeves, these can easily be dismounted if the contact sleeves have been damaged.
The twisted wires have a surrounding shield, which is coupled to the sleeve by means of the clamping ring, causing electric contact between shield and sleeve.
By coupling the shield to the sleeve of the connector the advantage by having the wires shielded through the length of the connector is attained, which is of great importance for signal integrity and signal/noise ratio.
According to an additional aspect of the invention, a signal transmission arrangement for couplers for automatic coupling of rail vehicles comprises a mountable terminal block, and a connector insertable in the terminal block arranged for termination of at least two incoming and pairwise twisted wires, wherein the terminal block having connector seats arranged in rows and columns. The signal transmission arrangement is characterized in that the connector has a cable terminator connectable to a spreader with contact pins embedded in a dielectric material, the contact pins extending through the spreader and in at least a part of their extension having a radial direction component adapted to the center distance between said connector seats.
In this way is a signal transmission arrangement provided in an automatic coupler which avoids the problems commonly associated with data transmission at higher data transmission speeds between coupled rail vehicles.
Preferred embodiments of the invention are specified in the independent claims.

SHORT DESCRIPTION OF THE FIGURES

The invention is further explained below in the detailed description of embodiment examples of the invention, with reference to the accompanying drawings, of which

Figure 1a shows the connector in a longitudinal cross section view in a mounted position;
Figure 1b shows the connector in a corresponding and exploded longitudinal cross section view;
Figure 2 shows the connector in an end view, and
Figure 3a-g shows corresponding end views of alternative embodiments of a spreader included in the connector.

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.
In fig. 1 is a shielded cable commonly designated 1 schematically shown that comprises twisted pairs of electric wires 2 which are connected to a connector commonly designated 3.
In the inventive connector is the wires 2 of the cable, coupled via one cable terminator commonly designated 4 to a spreader commonly designated 5 that distributes the signals in a geometrically desired way.
In order to mount a connector 3 on a cable 1 the cable must be prepared, which means that the outer covering 6 must be removed an appropriate distance, further must the electromagnetic shielding 7 be uncovered and finally must the wires in the twisted pair 2 also be stripped an appropriate distance.
The inner wires 2 of the twisted pair is provided with sleeve couplings 8 which are electrically connected to the wires 2, for example crimped or soldered onto the wires. The wires 2 and sleeve couplings 8 are mounted in the below described cable terminator 4.
The cable terminator 4 is operable for arresting the wires 2 of the twisted pair relative each other and relative the connector 3. In a preferred embodiment of the invention is the cable terminator 4 separable in at least two parts, one front part 9 and one rear part 10. The cable terminator 4 is further formed to arrest the sleeve couplings 8 for further connection.
The rear part 10 of the cable terminator has the form of a cylinder manufactured in a dielectric material, and having at least two paths 13 arranged in the longitudinal direction of the cylinder, the paths extends along the envelope surface of the cylinder and parallel with a center axis thereof. The paths 13 have a depth that is sufficient to completely laterally insert the sleeve couplings 8 therein. The paths 13 can further be arranged with a contraction 12 and thereby arresting the sleeve couplings 8 in the paths 13 in the longitudinal direction of the cable terminator 4.
The rear part 10 of the cable terminator has a groove 11 that extends around the cylinder in its front part, the groove 11 is operable for snap locking and arresting the front part 9 of the cable terminator by means of a snap-lock means configured for this purpose.
The front part 9 of the cable terminator is formed as a cap adapted to the rear part 10, the front part 9 has grip devices 14 arranged along the edge of the cap, and the grip devices 14 engage the groove 11 at the rear part 10 of the cable terminator. When snap-locking the front part 9 to the rear part 10 is the sleeve couplings 8 arrested in the rear part 10. In order to ensure the relative positions of the sleeve couplings 8 is the front part 9 provided with guide tubes 15 arranged on the outside of the cap.
The front end of the sleeve couplings 8 inserts into a rear part 16 of the spreader 5, and connects to electrical conducting contact pins 19 which inserts into holes 17 arranged in the rear part of the spreader. In this way are the wires 2 via the cable terminator 4 electrically coupled to the contact pins 19 in the spreader 5.
The spreader 5 is manufactured in a dielectric material with suitable material characteristics for the desired impedance; the spreader 5 of the example embodiment comprises a front part 18 and a rear part 16. In this way is the spreader 5 separable which means that the contact pins 19 can easily be mounted in the spreader 5, which means that individual contact pins 19 can be replaced. Replaceable contact pins 19 are preferred from a service point of view due to the fact that individual contact pins can be replaced without dismounting the cable 1 from the connector 3.
The contact pins 19 extend through the rear part 16 of the spreader which has paths 38 arranged for the contact pins 19. The paths extend axially through the rear part 16 of the spreader, and extend lowered or at least partially lowered with a radial direction in the front end plane of the rear part 16. In a corresponding way can the grooves 38 for the contact pins have a radial and at least partially lowered extension in the rear end plane of the front end 18 of the spreader, from there extends the groove axially and parallel with the center axis of the connector 3 through the front part 18 of the spreader. The contact pins 19 extend through the front part 18 and through a formed throat 37 on the same for coupling to a mating connector.
The spreader 5 of the inventive connector 3 can have a plurality of shapes and also a varying number of contact pins 19. Figure 3a shows a spreader with sharp corners that is arranged for four contact pins. Figure 3d shows a spreader with sharp corners with only two contact pins. The figures 3b, 3e, 3c, 3f and 3g all have spreaders with rounded shapes and varying number of contact pins 19. It goes without saying that the other parts of the connector must be adapted to the shape of the spreader.
On the front part 18 of the spreader is contact sleeves 20 arranged around the contact pins 19. The contact sleeves 20 is operable for guiding a mating connector at the event of coupling, it also fulfills the function to electrically couple the shield 7 of the cable to the shield of the mating connector. The contact sleeves 20 are connected to the sleeve 24 by means of a locking washer 21 that is removable connected to the sleeve 24 and holds the contact sleeves 20 in position by means of a flange 22 at the foot of the contact sleeves 20, and the locking washer 21 has a corresponding recess 40 formed around a through hole arranged for the contact sleeve 20.
The cable terminator 4 and the spreader 5 is held together by means of a sleeve 24 having a front seat 36 arranged to house the spreader 5, whereby the latter by form fitting in the seat will be firmly attached to the sleeve 24. The sleeve 24 is internally dimensioned for radially arresting the cable terminator 4 received by the sleeve. The sleeve 24 is provided with at least one threaded hole 25 that mouth into the end surface of the sleeve, the threaded hole 25 is used for mounting the locking washer 21 whereby the contact sleeves 24, the spreader 5 and the cable terminator 4 are arrested radially and in one longitudinal direction of the connector 3.
The sleeve 24 also exhibits a threaded part 26 in its rear end, which aims to bring a shell 32 in threaded engagement with the sleeve 24.
In the rear end of the sleeve 24 is a seat 27 arranged for housing a clamping ring 28, the clamping ring 28 is arranged to press the shield 7 of the cable 1 against the rear seat 27 of the sleeve and thereby lock the shield 7. This connection also ensures an electrical connection between the sleeve 24 and the shield 7. An electrical connection between the shield 7 and the connector 3 is of utter importance for suppressing interference and cross-talk.
The clamping ring 28 has a through hole for insertion of the cable 1 and having a front stop 29, a rear stop 30 and a beveling 31. The rear stop 30 is arranged to be brought in contact with the shell 32 when the shell is screwed on the sleeve 24. The front stop 29 of the clamping ring brings the shield 7 in contact with the sleeve 24.
The inner diameter of the clamping ring 28 is dimensionally adapted to the desired cable 1 and is provided with the inner beveling 31 in order to facilitate the insertion of the cable 1. By locking the shield 7 to the connector 3 by means of the clamping ring 28 is also a tension relief for the cable 1 provided, which tension relief also protects the wires 2 of the cable against fracture when an axial force is applied on the cable in a longitudinal direction of the connector 3.
The shell 32 having an internal thread 33, which is arranged to be brought in threaded engagement with the threaded rear part 26 of the sleeve. The shell 32 also exhibits a stop 34 arranged on its inside, which stop 34 is brought in contact with the clamping ring 28 at said threaded engagement. In the shell 32 is also a relief 35 attached for protection of the cable 1 against external damage.
In fig. 2 is the connector shown in an end view. The locking washer 21 is removable attached to the shell 32 by means of screws 23. Contact sleeves 20 are arranged around the throats 37 that extend from the front part 18 of the spreader. The contact pins 19 are arranged centered in said throats 37 and contact sleeves 20.
The shown embodiment shall generally be considered as an example of a solution to the problem of creating an interface between a dimensionally thin cable with pair-wise twisted wires and a dimensionally robust connector suitable for use in harsh conditions.
The shown embodiment is especially developed and suitable for use in an arrangement for transmission of data at high speed between vehicles in a rail-bound train, wherein the need to isolate the signal paths from outer interference is especially hard to fulfill due to vibrations and shocks, and due to demands on the connector in terms of robustness in order to allow and withstand automatic coupling of the vehicles.
The invention can therefore in a second aspect nevertheless be considered as a signal transmission device between coupled rail vehicles, wherein the above specified connector is dimensioned to cooperate with a terminal block arranged to be carried on a draft gear intended for automatic coupling of rail vehicles. Such a terminal block is preferably formed as a block made of a non-conducting material, such as a polymer material, and comprises seats for the connectors formed as through holes arranged on rows and columns in form of a perpendicular matrix. The contact seats are formed for insertion of the contact sleeves 20 of the connector from the back side of the terminal block. Thereafter, is an extension of the contact pins 19 inserted from the front side of the terminal block for electric connection with the contact pins 19. This extension connector can be formed as either a male or female connector which is arranged to mate with a corresponding extension connector in the terminal block of the mating couple. To facilitate the arrest of the connector 3 in the connector seats of the terminal block can the contact sleeves 20 as in the embodiment example be provided with snap-lock devices in the form of lugs 39 which is arranged in such a way that during mounting a correspondingly shaped shoulder arranged inside the contact seat arrest said lugs 39. Insertion of the contact sleeves in the seats of the terminal block is facilitated if the contact sleeves is axially slitted and elastic compressible in a radial direction.

Claims

A connector (3) configured for termination of at least two incoming and pairwise twisted wires (2), comprising a spreader (5) connectable to a cable terminator (4), the spreader having contact pins (19) embedded in a dielectric material, the contact pins 19 extending through the spreader (5) and in at least a part of its extension having a radial direction component, characterized in, that the spreader (5) is separable in a front part 18 and a rear part 16, the parts having paths (38) arranged for the contact pins (19).
A connector (3) according to claim 1, wherein said paths (38) extend at least partially in a distribution plane perpendicular to a longitudinal axis of the spreader (5) and said paths (38) are angularly equally spaced in the distribution plane.
A connector (3) according to claim 1 or 2, comprising a sleeve (24) that extends coaxially with the spreader (5), the sleeve (24) comprises a front seat (36) arranged to house the spreader (5).
A connector (3) according to any of claim 1 to 3, comprising a cable terminator (4), having for each conductor (2) an electrical connection element (8) that connects the conductor (2) to a contact pin (19) in the spreader (5).
A connector (3) according to claim 3, wherein said sleeve (24) has a through hole with an internal dimension that is configured to radially fix the cable terminator (4) in the sleeve (24).
A connector (3) according to claim 3 or 5, wherein said sleeve (24) comprises a seat (27) arranged to receive a clamping ring (28) insertable in the rear end of the sleeve (24), which seat (27) comprises a stop for said clamping ring (28), wherein said clamping ring (28) forms a rear axial stop for the cable terminator (4) in the sleeve (24).
A connector (3) according to claim 3, 5 or 6, comprising a shell (32) arranged to threadingly engage a threaded rear part of the sleeve (26), which shell (32) comprised a stop (34) that presses against the clamping ring (28) as the shells (32) engages the sleeve (24), for locking the clamping ring against the sleeve (24).
A connector (3) according to claim 3, 5, 6 or 7, comprising a locking washer (21) arranged to be removably mounted on a front end surface of the sleeve (24), whereby the spreader (5) is axially arrested in the sleeve (24).
A connector (3) according to claim 8, wherein each of the contact pins (19) has a contact sleeve (20) arranged centered around the contact pin (19) and is fixated against the sleeve (24) by the locking washer (21).
A connector (3) according to any preceding claim, wherein said incoming pairwise twisted wires (2) have a surrounding shield (7), which shield (7) by means of the clamping ring (28) is coupled to the sleeve (24) causing electric contact between the shield (7) and the sleeve (24).
Signal transmission arrangement comprising a terminal block arranged on a coupler for automatic coupling of rail vehicles, and a connector (3) according to any preceding claim insertable into the terminal block arranged for termination of at least two incoming and pairwise twisted wires (2), wherein the terminal block comprises contact seats arranged in rows and columns.