Patent Application
20090134548
The present invention relates to a method for producing a signal plate and a traffic signal with a signal plate produced according to the above method.
Different types of traffic signals are currently used to control traffic flows. On the railways train traffic is predominantly still controlled using light signals, which may be of widely differing types. All light signals generally have in common a signal plate, into which the luminous points are inserted. This signal plate is traditionally made of metal and designed for stability reasons either with elements that are curved at the sides and/or with a second supporting metal plate. The holes for the individual luminous points have to be created in the signal plate and the luminous points then have to be inserted into the holes and secured there. The metalworking required to do this means the method is complex and makes it necessary to provide further elements on the signal plate to secure the luminous points.
The object of the present invention is therefore to specify a method which can be used to provide a traffic signal with less outlay. A traffic signal of such type will also be specified.
According to the invention this object is achieved with regard to the method by a method for producing a signal plate, in particular a signal plate for a railway signal, which comprises the following method steps:
a) providing a casting mold corresponding to the external form of the signal plate;
b) inserting at least one luminous point and/or at least one empty receptacle into the casting mold;
c) filling the casting mold with a free-flowing curable plastic to create a casting;
d) curing the plastic; and
e) removing the casting and in the case of cast-in empty receptacles inserting luminous points into the empty receptacle.
This allows the signal plate to be produced in a very simple manner, because the working process is simplified very significantly, in that the luminous points and/or the empty receptacles are positioned in the positions provided for them and are held by friction lock and form fit during the course of the casting process and the subsequent curing. Further processing steps to secure the luminous points and/or the empty receptacles are no longer required. It should be noted that a luminous point here refers to an insert with an integrated or integrable light source (e.g. an incandescent lamp, LED, etc.).
It is comparatively simple to arrange the luminous points and/or the empty receptacle, if the luminous point and/or the empty receptacle has an essentially cylindrical housing and is inserted into the casting mold in an essentially perpendicular orientation to the plane of the casting mold. In principle however the housing can have any cross-sectional form because the free-flowing nature of the plastic allows easy adjustment to pretty well any cross-sectional forms.
In order on the one hand to have to use comparatively little plastic and on the other hand still to achieve sufficiently firm anchoring of the luminous point and/or the empty receptacle in the plastic, in one embodiment of the invention provision can be made to cast the luminous point and/or the empty receptacle to a depth corresponding to its diameter as a maximum.
To increase the mechanical stability of the signal plate before filling the casting mold at least one structurally reinforcing element can be inserted into the casting mold. This structurally reinforcing element can then be cast in together with the luminous point and/or the empty receptacle in a single operation. It is thus possible to avoid the arrangement of further structurally reinforcing elements, which means that further manufacturing steps compared with conventional metal signal plates can be omitted. One structurally reinforcing element that is particularly preferred due to its ease of handling can be a glass-fiber mat for example.
To reliably prevent the plastic cast into the casting mold flowing under the luminous point and/or the empty receptacle, the luminous point and/or the empty receptacle can be pressed onto the casting mold when the casting mold is filled.
In order for example to allow the luminous point and/or the empty receptacle to move out of the plane of the signal plate, the casting mold can have at least one projection, into which the luminous point and/or the empty receptacle is inserted. The at least one projection can also be formed so that formed elements assigned to the luminous point and projecting from the plane of the signal plate, in particular protective or screening elements, are produced at the same time during filling. It is thus possible to form side shutters, extensions or other elements projecting from the plane of the signal plate directly when casting the signal plate. These elements can be connected to the luminous point and/or the empty receptacle permanently at the same time.
In order to be able to configure these in a particularly stable manner out of the plane of the signal plate, it is possible, before filling the casting mold, to insert at least one further structurally reinforcing element into the projection. Particularly suitable for this purpose is for example the above-mentioned glass-fiber mat, which is bent into the projection in the regions on which a luminous point and/or an empty receptacle would otherwise rest. Therefore the holes in the glass-fiber mat for the luminous points and/or the empty receptacle are not cut out as such and the cut-out sections removed but with a corresponding cut from the center of the hole radially to the edge, the segments still held at the edge of the hole can be folded into the projection and cast in there later with the plastic.
According to the invention the above-mentioned object is achieved with regard to the traffic signal by a traffic signal, in particular a railway signal, which has a signal plate produced by casting plastic, into which at least one luminous point and/or at least one empty receptacle is cast with a friction lock and form fit.
In an advantageous development of the invention to achieve a sufficiently high level of stability at least one structurally reinforcing element, in particular a glass-fiber mat, can be cast into the signal plate.
Exemplary embodiments of the invention are described in more detail below with reference to the drawing, in which:
In step b) a glass-fiber mat 10 is then inserted into the casting mold 4 avoiding the area provided for the luminous points 8. The glass-fiber mat 10 serves as a structurally reinforcing element rendering further strengthening of the signal plate 2 unnecessary. In step c) the casting mold 4 is filled with a free-flowing, curable plastic to create a cohesive casting with the integrated luminous points 8 and the simultaneously cast-in glass-fiber mat 10. An epoxy resin, which is a combination of a liquid resin and a hardening agent, which is cast and then hot-cured, is suitable for this purpose. Additionally or alternatively polyurethane and/or even laminated carbon fibers, so-called composite materials, can be used.
Alternatively a little of the plastic could be cast first into the casting mold and the glass-fiber mat 10 laid on top of the still soft plastic and the casting mold 4 then filled. Curing the plastic gives the finished signal plate 2, as shown in a front view in step d), which is then removed from the casting mold 4. In the case of cast-in empty receptacles the luminous points 8 would then have to be inserted into the empty receptacles.
As shown in
The ratios in
In the selected diagram in
The signal plates 2, 14 described above can thus be integrated in a simple manner in a traffic signal, for example a railway signal. The signal plates 2, 12 used in this process are simple to manufacture, because the working process is greatly simplified, in that the luminous points 8 and/or the empty receptacles are positioned at the places provided for them and are held by friction lock and form fit during casting and the subsequent curing. Further substantial processing steps to secure the luminous points 8 and/or the empty receptacles are no longer required.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2006/010481 | 10/31/2006 | WO | 00 | 6/5/2008 |
