BACKGROUND

The invention relates to an arrangement of a railway sig nal .

The invention further relates to a back part of the rail way signal .

The invention further relates to a front part of the rail way signal for co-operation with the back part.

Railway signals are safety relevant products and have to fulfil safety regulations, for example up to SIL 4 accord ing to EN 61508 ( IEC 61508 /IEC61511 ) .

Conventional railway signals are provided with bulbs com prising one or more filament (s) . In case the filament is broken, it has to be changed. There are some standardized bulbs for signalization, having specialized sockets. This socket is in fact a mechanically and electrically coded interface, securing usage of correct light source only. The change work is easy to do without touching electrical connection or need for re-adjusting signal, and thus it can be realized by unskilled workers, even under bad weather conditions.

Recently, LED-light technology has proceeded rapidly. LED- lights has several advantages over filament bulb(s) . LED- lights has a very high life time and capability to produce colors needed.

However, changing over to LED-light sources is far more complicated because of at least four reasons: a) there are huge variations in colors that LEDs may provide; b) LEDs need specific individually configured electronics to be driven in a correct and safe way; c) electronics of LEDs has to be protected from electromagnetic disturbances; d) LEDs need for forced cooling by heat conduction.

A problem is that existing LED-signal constructions do not keep the existing safety level of maintenance, especially when changing the light source.

BRIEF DESCRIPTION

Viewed from a first aspect, there can be provided arrange ment of a railway signal, comprising a LED light source, a back part comprising said LED light source, a front part, an arrangement of light optics arranged in the front part, said arrangement of light optics allowing light of said LED light source to exit the railway signal in a con trolled way, said back part being attached demountably to said front part by an interface, the interface comprising a back part contact surface and a front part contact sur face, wherein the interface comprises an indexing system, including a back part indexing member arranged in the back part contact surface, the back part indexing member being specific for the light of the LED light source and allowed front part(s), and a front part indexing member arranged in the front part contact surface, the front part indexing member being specific for the properties of the light op tics of said front part and allowed back part(s), wherein the indexing members being shaped to prevent an attachment of the back part to the front part in case of mismatch of said indexing members.

Thereby a railway signal wherein mistakes when changing a failed LED-source, even by unskilled persons, may be pre vented or at least reduced.

Viewed from a further aspect, there can be provided a back part of the railway signal, the back part comprising a LED light source, a back part contact surface, wherein the back part further comprises a back part indexing member arranged in the back part contact surface, the back part indexing member being specific for the LED light source and allowed front part(s) .

Thereby a back part of a railway signal that prevents or at least reduces mistakes when changing a failed LED- source, even by unskilled persons, may be achieved.

Viewed from a still further aspect, there can be provided a front part of the railway signal for co-operation with the back part defined above.

Thereby a front part of a railway signal that prevents or at least reduces mistakes when changing a failed LED- source, even by unskilled persons, may be achieved.

The arrangement and the method are characterised by what is stated in the characterising parts of the independent claims. Some other embodiments are characterised by what is stated in the other claims. Inventive embodiments are also disclosed in the specification and drawings of this patent application. The inventive content of the patent application may also be defined in other ways than defined in the following claims. The inventive content may also be formed of several separate inventions, especially if the invention is examined in the light of expressed or implic it sub-tasks or in view of obtained benefits or benefit groups. Some of the definitions contained in the following claims may then be unnecessary in view of the separate in ventive ideas. Features of the different embodiments of the invention may, within the scope of the basic inventive idea, be applied to other embodiments.

In an embodiment, the indexing system comprises a protrud ing part, such as a pin or ridge, projecting from one of the contact surfaces, and as a counterpart, a pit arranged to another one of the contact surfaces. An advantage is that the indexing system may be realized in a simple and reliable way that is allowing the change work done by un skilled workers even under bad weather conditions.

In an embodiment, the protruding part and/or the pit has a cross-section of a polygon, or the cross-section comprises points and bays. An advantage is that the number of varia tions in the indexing system may be broadened in a simple way .

In an embodiment, the protruding part has a shape that fits exactly with the pit. An advantage is that the cor rectness of the matching of the back and front parts may be easily ensured. In an embodiment, said exact fitting is arranged in the connector. An advantage is that an excel lent electrical contact without mechanical tension or dis location may be achieved.

In an embodiment, the protruding part has a shape or di mensions making a loose fit with the pit. An advantage is that a tolerance facilitating the attachment of the parts and against mutual rotation of the parts may be created. In an embodiment, there is an exact fit in direction of possible rotation, but a loose fit in other directions.

In an embodiment, the back part contact surface is ar ranged at least partially in a circuit board. An advantage is that the features or properties of the circuit board may be indexed directly.

In an embodiment, the circuit board comprises the LED light source. An advantage is that the features or proper ties of the LED light source, like light colour and/or in tensity may be indexed directly. In an embodiment, one of the contact surfaces comprises also a supplementary or extra indexing member being with out a counter indexing member in another one of the con tact surfaces, the supplementary or extra indexing member arranged to permit correct attachment of the back part to the front part. An advantage is that the varieties of the indexing system may be broadened and also extended in pur poses potentially existing in future.

In an embodiment, an electrical conductor for feeding electricity to the LED light source is arranged to enter in the front part, said electrical conductor being con nected to the LED light source by through a releasable electrical connector arranged between the front part and the back part. An advantage is that in case the back part is to be changed, the electrical conductor needs not to be removed from the signal, which makes the changing of the back part easier especially under bad weather conditions. Further advantage is that the electrical conductor may be arranged hidden in a metallic hose, and thus protected against vandalism.

In an embodiment, the electrical connector is arranged to close in consequence of connection of the back part to the front part. An advantage is that it is simple to attach the pack part to the front part, and that re-attaching of the connector may not be forget.

In an embodiment, at least part, or even all, of the in terface is arranged in the releasable electrical connect or. An advantage is that the front and the back part them selves are not affected by indexing system during their production process. In an embodiment, the indexing member is provided with a visible marking indicating the meaning of said indexing member. An advantage is that the purpose of the indexing marking may be visually checked and communicated for cor rect spare part.

In an embodiment, the arrangement comprises a gasket sys tem arranged to seal the back and front parts attached to each other and closing the indexing system therein. An ad vantage is that the indexing system is shielded against the elements, and thus there is no need for a weatherproof connector .

In an embodiment, the gasket is attached to the back part. An advantage is that the gasket will be automatically changed together with the pack part, and thus the level of shielding may be kept high.

In an embodiment, the interface is adapted for conducting heat from the back part to the front part and cooling the LED light source. An advantage is that the front part may be utilized in cooling the light source.

In an embodiment, a transformer adapted to transform elec tricity suitable for the LED light source is arranged in the front part. The transformer may be a toroidal trans former, arranged to surround a pathway of the light of the LED light source. Advantages are that very compact struc ture of the front part may be achieved, there may be bet ter protection against EMC (electrical fields influence) , and also less mounting work.

In an embodiment, the arrangement comprises attaching means for attaching the signal to a place of operation thereof, the attaching means being arranged in the front part. An advantage is that when changing the back part, the signal needs not to be removed from its place of oper ation, and that a re-adjustment of the signal is not nec essary .

In an embodiment, the back part indexing member is ar ranged to identify at least one of the following property of the back part: light color or colors, light intensity, particulars of the electrical connection, and size. An ad vantage is that the key features of the back part may be identified .

In an embodiment, the front part indexing member is ar ranged to identify at least one of the following property of the front part: size, light distribution, attaching means, light color or colors, light intensity, transform er, and particulars of the electrical connection. An ad vantage is that the key features of the front part may be identified .

BRIEF DESCRIPTION OF FIGURES

Some embodiments illustrating the present disclosure are described in more detail in the attached drawings, in which

Figure 1 is a schematic view of an arrangement of a rail way signal,

Figure 2 is a schematic side view of an arrangement of a railway signal in partial cross-section,

Figure 3 is a schematic side view of another arrangement of a railway signal in partial cross-section,

Figure 4 is a schematic side view of a third arrangement of a railway signal in partial cross-section, Figures 5a - 5d show schematic views of details of ar rangements of a railway signal in partial cross-section,

Figures 6a - 6d are schematic views of a details of anoth er arrangement of a railway signal in partial cross- sections, and

Figure 7 a schematic side view of a detail of a still an other arrangement of a railway signal in partial cross- section .

In the figures, some embodiments are shown simplified for the sake of clarity. Similar parts are marked with the same reference numbers in the figures.

DETAILED DESCRIPTION

Figure 1 is a schematic view of an arrangement of a rail way signal .

A signal 1 is a device erected beside a railway line to pass information relating to the state of the line ahead to engine drivers. The driver interprets the signal's in dication and acts accordingly. Typically, a signal might inform the driver of the speed at which the train may safely proceed or it may instruct the driver to stop.

It is to be noted, that in this description the term "sig nal" means an electric signal comprising a LED light source 2. The LED light source 2 is a part of the signal housing, containing electronics that is shielded by the housing and providing at least a heat sink. The signal is arranged in a place of operation that may be e.g. a mast or some other framework. One framework may comprise one or plurality of signals.

The signal 1 comprises attaching means 3 for attaching the signal 1 to the place of operation. According to an as- pect, the attaching means 3 are arranged in a front part 5 of the signal. The details of the front part 5 are dis cussed later in this description.

A back part 4 is attached demountably to the front part 5 by an interface 7. The interface 7 comprises a back part contact surface in the back part 4, and a front part con tact surface arranged in the front part 5. In an embodi ment, the parts 4, 5 are fixed to each other by fastening means 10, such as screw (s) .

A frames or base structure of the back part 4 and the front part 5 may be made of e.g. metal, plastic or compo site material. Metal, especially die casted aluminium, is preferable material, since it has good heat conduction and distribution properties.

An electrical conductor 14 is attached to the front part 5. In the shown embodiment, the conductor 14 is connected to a transformer 17 and an electrical connector 15 via a terminal clamp 24.

Figure 2 is a schematic side view of an arrangement of a railway signal in partial cross-section and front part de tached from back part.

The arrangement 100 comprises a LED light source 2 that is arranged in a back part 4 comprising said LED light source 2, a front part 5, and an arrangement of light optics 6 arranged in the front part 5.

The arrangement of light optics 6 allows light of said LED light source 2 to exit the railway signal 1 in a con trolled way. The arrangement of light optics 6 may com prise one or more lens parts, for instance. The interface 7 comprises an indexing system 11, including a back part indexing member 12 arranged in the back part contact surface 8, and a front part indexing member 13 ar ranged in the front part contact surface 9.

The back part indexing member 12 is specific for the light of the LED light source 2 and front part(s) that is/are allowed to connect with the back part 4. Analogously, the front part indexing member 13 is specific for the proper ties of the light optics of the front part 5 and back part(s) that is/are allowed to connect with the front part 5. In practice this means that the indexing members 12, 13 are shaped to prevent a correct attachment of the back part 4 to the front part 5 in case of mismatch of said in dexing members. Some embodiments of the indexing members 12, 13 are described later in this description.

In an embodiment, the indexing system 11 is integrated to the structure of the arrangement such that the system 11 cannot be removed from the arrangement 100 without break ing the arrangement.

There are various ways to realize the indexing system 11. In an embodiment, the indexing system 11 comprises at least one protruding part 18 projecting from one of the contact surfaces 8, 9, and as a counterpart, a hole or a pit 19 arranged to another one of the contact surfaces 8, 9. The protruding part 18 may comprise a pin, the cross- section of which is e.g. round or circle, polygon, or any "free" shape comprising points and bays. The points and bays may, for instance, create a star-like cross-section. In an embodiment, the protruding part 18 comprises at least one ridge. The pit 19 may have a corresponding shape . In the shown embodiments, the protruding parts 18 are pins (such as metallic pins) that are attached to the base plate of the contact surface 8, 9.

In an embodiment, the indexing system is integrated to and undetachable from the structure of the arrangement.

According to an aspect of the invention, the length of the protruding part 18 or the pit 19 is a variable of the in dexing system. This feature may be combined or not with above described variations in cross-sections of the index ing members .

In an embodiment, the protruding part 18 and the corre sponding pit 19 have shapes and dimensions such that there is a tight fit therebetween. In another embodiment, the protruding part 18 has a shape or dimensions making a loose fit with the pit 19.

In still another embodiment, the protruding part 18 and the pit 19 are shaped or dimensioned such that there is a loose fit in one direction and a tight fit in another di rection .

Not only the shape and size of the indexing members 12, 13 have a role in realization of the indexing system 11, but also placing or positioning of the indexing members 12, 13 in the indexing system 11.

According to an aspect of the invention, one of the con tact surfaces 8, 9 may comprise at least one supplementary or extra indexing member 20 being without a counter index ing member in another one of the contact surfaces 8, 9. The extra indexing member 20 permits a correct attachment of the back part 4 to the front part 5, provided, of course, that the rest of the indexing members 12, 13 are allowing the attachment.

According to an aspect of the invention, the indexing sys tem 11 provide all the differences or important particu lars to be indexed. For instance, if different sized front parts 5 need the same LED light source 2, an indexing mem ber defining or limiting the size are missing in the in terface 7. Thus the index system 11 allows correct attach ment of said front parts in a back part 4 comprising said light source.

In another case, if a front part 5 having bigger front lens part needs a stronger LED light source 2, i.e. more light intensity, then there is an indexing member in the front part indexing members 13 allowing just back parts 4 having the right intensity to be attached.

The arrangement comprises an electrical conductor 14 for feeding electricity to the LED light source 2. In an em bodiment, the electrical conductor 14 is arranged to enter in the railway signal 1 via the front part 5, and connect ed to the LED light source 2 by through a releasable elec trical connector 15 arranged between the front part 5 and the back part 4. In an embodiment, the electrical connect or 15 is arranged to close the electrical connection when the back part 4 is connected to the front part 5.

In an embodiment, the arrangement 100 comprises a gasket system 16 that is arranged to seal the back and front parts 4, 5 attached to each other, and furthermore to close the indexing system 11 therein. The gasket system 16 may comprise e.g. one or more elastic gasket ring(s) . In an embodiment, the gasket system 16 is attached to the back part 4. In an embodiment, the interface 7 is adapted for conduct ing heat created in the LED light source 2 from the back part 4 to the front part 5, thus cooling the LED light source. This function may be realized by e.g. metallic or other well heat conducting elements or sections of the in terface 7 that have connections both to the LED light source 2 and a cooling means arranged in the front part 5. In an embodiment, said cooling means comprises simply the casing of the front part 5.

In an embodiment, the arrangement comprises a transformer 17 arranged in the front part 5. The transformer 17 trans forms electricity fed in the signal 1 in a suitable volt age and/or current for the LED light source 2. According to an idea, the transformer 17 has a toroidal shape. This kind of transformer reduces cables needed for installa tion, provides low voltage only within the signal housing, and has low spreading magnetic field.

In an embodiment, the toroidal transformer 17 is arranged to surround a pathway of the light of the LED light source 2, i.e. at least part of the light passes through the ap erture 23 of the toroidal transformer 17. Preferably, all the active light needed in the light optics 6 passes through the aperture 23, as shown e.g. in Figure 1.

Figure 3 is a schematic side view of another arrangement of a railway signal in partial cross-section. Basically, this embodiment of the arrangement 100 is similar to that shown in Figure 2. The diameter of the front part 5 and the optics therein is larger, and furthermore the back part 4 is longer, e.g. for making it possible to envelope more powerful electrical components and provide more cool ing surface. However, the interface 7 is dimensioned in a same way in the both embodiments. Also, the indexing systems 11 have a same layout or configuration, that is, the indexing mem bers 12, 13 and the connector 15 are placed in the same areas or section in the interface 7.

It is to be noted, however, that in some embodiments also the layout of the interface 7 may have a role in estab lishing the indexing system 11.

Figure 4 is a schematic side view of a third arrangement of a railway signal in partial cross-section.

Also this embodiment of the arrangement 100 is basically similar to that shown in Figure 2, and thus also to that shown in Figure 3. Now the diameter of the front part 5 and the optics therein is small, and the back part 4 is shorter. This kind of very compact structure is advanta geous in circumstances where it is not needed much power. Typically, this kind of arrangement is used for small shunting signals.

The interface 7 is dimensioned in a same way as in the em bodiments shown in Figures 2 and 3. Also, the indexing systems 11 have a same layout. It can be concluded that the indexing system 11 is the same in the embodiments.

However, there are variations in indexing members 12, 13. Each of the back and front parts 4, 5 shown in Figures 2 - 4 has indexing members of its own.

As described above, the indexing system 11 comprises a back part indexing member 12 and a front part indexing member 13. The indexing members 12, 13 identify important properties of the part itself, but also they define the allowed counterpart ( s ) . In an embodiment, the back part indexing member 12 identi fies at least one of the following property of the back part 4: light color or colors (in case the LED light source have an ability to create more than one color) , light intensity, particulars of an electrical connection, and size.

In an embodiment, the front part indexing member 13 is ar ranged to identify at least one of the following property of the front part 5: size, light distribution, attaching means, light color/colors , light intensity, transformer, and particulars of an electrical connection.

In an embodiment, the indexing member 12, 13 is provided with a visible marking 21 indicating the meaning of said indexing member 12, 13. The marking 21 may comprise e.g. a color marking, a symbol such as letter (s), etc.

Figures 5a - 5d show schematic views of details of ar rangements of a railway signal in at least partial cross- sections .

The embodiment of back and front part contact surfaces 8, 9 shown in Figure 5a comprises pin-like protruding parts 18 and pits 19. As can be seen, the protruding part may be dimensioned to just reach the corresponding pit, or essen tially longer such that the protruding part may reach some parts of indexing system arranged behind the interface 7.

In an embodiment, the contact surface 8, 9 comprise one or more pits 19 that are closed by a plug 25 so that no pro truding part may enter the pit. The closed pit 19 is one alternative to realize a back part or a front part index ing member 12, 13. The excessive pit 19 closed this way may also be advantageous to realize the indexing system 11. An embodiment of the indexing system 11 utilizing com- binations of protruding parts 18, pits 19 and plugs 25 is based on a grid of pits (an embodiment shown in Figure 6d) that is manufactured to the parts to be indexed. Then, in some pits of the grid, there are attached protruding part(s) and/or plug(s) according to the indexing system. This way it is possible to vary the indexing without any need for individual modifications of the back and front parts 4, 5, and thus manufacturing of the parts may be simplified .

Figure 5b is showing further embodiments of the back and front part contact surfaces 8, 9. In an embodiment, the pit is not a through hole, but a blind hole. This feature may extend the variations of the indexing system 11, since the length or deepness of the pit is a variable of the system.

Figure 5b is also showing embodiments of the protruding parts 18 wherein the protruding part does not extend through the structure it is attached, but is, for in stance, attached in a blind hole or attached to said structure in moulding or casting process thereof.

Figure 5c is a top view of an embodiment of contact sur faces in cross-section. The protruding part 18 and also the pit 19 may have a cross-section of a polygon, or cross-section comprising points and bays. In the shown em bodiment, the cross-section is like a star. Number of points and bays may, of course, vary, as well as dimen sions and proportions of dimensions. Still another embodi ment of the protruding part 18 and the pit 19 is shown in Figure 5d. In this embodiment, there is also a visible marking "B" indicating the meaning of the indexing member.

Figure 5d is shown a side and top view of an embodiment of contact surfaces from side and top in cross-section. Figures 6a - 6d are schematic views of a details of anoth er arrangement of a railway signal in partial cross- sections .

According to an aspect of the invention, at least part of the interface 7 is arranged in a releasable electrical connector 15, an embodiment of which being shown in Figure 6c. In an embodiment, the whole interface 7 is arranged in the releasable electrical connector 15. The indexing sys tem 11 may then comprise indexing members 12, 13 realized by e.g. cross-sectional shape and dimensions of the con nector 15, size, positioning and number of contacts in cluded in the connector 15, positioning of male and female contacts, etc.

In an embodiment, the electrical connector 15 may comprise a selectable number of pins 30 and sockets 31 provided with integrated crimping ports 26 to be crimped onto wires 28, as shown in Figure 6a. The pin 30 and the socket 31 may also comprise a snap spring 27 that attaches the pin 30 or the socket 31 in a base part 32 provided with affil iated positions and spring cavities 29. Assembling the electrical connector 15 may be fully automated, using se- ries of connected pins and sockets as shown in Figure 6b, available on reels and using suitable tooling, like in au tomotive electrical harness production.

As shown in Figure 6c, the pins 30 and sockets 31 attached in the base part 32 makes the protruding part(s) 18 and the pit(s) 19 of the electrical connector 15, respective ly. The base part 32 may also create an isolating connect or housing as shown in Figure 6c. In an embodiment, the electrical connector 15 contains al so mechanical indexing members 34, as shown in Figure 6c. The mechanical indexing members 34 arranged in the con nector may comprise e.g. walls, pins, etc.

In an embodiment, at least some of the pins 30 and/or sockets 31 in the connector 15 are used for mechanical in dexing only, i.e. there are pins and/or sockets without connection to a wire etc. Figure 6d is showing a grid of holes 33 integrated into a base part 32. Similar grid 33 is arranged in both the back part 8 and the front part 9 contact surfaces. In the grid 33 there have been assembled pins 30 without wires in order to mechanically indexing the corresponding back 4 or front part 5. If at least one pair of pins coincides (as shown by C in Figure 6d) , there is a mismatch and an attachment of the back part 4 to the front part 5 is excluded. The same will happen also when using sockets instead of pins. It is to be noted, however, that the pins and/or sockets may also have different con struction with similar mechanical indexing functionality, for instance they can be made from plastics etc.

As described earlier in this description, the whole inter face 7 is arranged in the releasable electrical connector 15. The indexing system 11 may then comprise indexing mem bers 12, 13 realized by e.g. electrical connector pins 30 in the connector 15, by their size, positioning and number in the connector 15, positioning of male and female con tacts, etc.

Advantage of the embodiments wherein the interface 7 is arranged in the releasable electrical connector is that it is possible to unrestrictedly vary the indexing without any need for individual modifications of the back and front parts 4, 5.

Figure 7 a schematic side view of a detail of a still an other arrangement of a railway signal in partial cross- section. According to an aspect of the invention, at least part of the back part contact surface 8 is arranged in a circuit board 22. Especially hole or pit type of indexing members are preferable here, but also protruding indexing members may be used.

In an embodiment, the circuit board 22 is a circuit board that comprises the LED light source 2. In this embodiment, indexing members relating to the light color and intensity of the LED light source 2 are preferably used.

The invention is not limited solely to the embodiments de scribed above, but instead many variations are possible within the scope of the inventive concept defined by the claims below. Within the scope of the inventive concept the attributes of different embodiments and applications can be used in conjunction with or replace the attributes of another embodiment or application.

The drawings and the related description are only intended to illustrate the idea of the invention. The invention may vary in detail within the scope of the inventive idea de fined in the following claims.

REFERENCE SYMBOLS

1 railway signal

2 LED light source

3 attaching means

4 back part

5 front part

6 arrangement of light optics 7 interface

8 back part contact surface

9 front part contact surface

10 fastening means

11 indexing system

12 back part indexing member 13 front part indexing member

14 electrical conductor

15 electrical connector

16 gasket system

17 transformer

18 protruding part

19 pit

20 extra indexing member

21 marking

22 circuit board

23 aperture

24 terminal clamp

25 plug

26 crimping port

27 snap spring

28 wire

29 spring cavity

30 pin

31 socket

32 base part

33 grid

34 mechanical indexing member coinciding members arrangement