EP-4741251-A1 - LIGHT SIGNAL FOR CONTROLLING A MEANS OF TRANSPORTATION

Abstract

The present invention is therefore based on the objective of providing a light signal whose light points can always be reliably perceived, even in winter weather conditions. The problem is solved according to the invention by a light signal (2) for controlling a means of transport, in particular a rail vehicle, comprising: a) at least one luminous point defining a volume in which a light source (4) associated with that luminous point is arranged; b) a front glass (8) that limits the volume in the direction of emission and is transparent to the light from the light source, c) a heating element (6, 18) arranged in the volume and/or in the front window (8); and d) a control circuit (12) for supplying the light point (4) and the heating element (6, 18) with electrical power, wherein a constant current source (32) is provided for supplying the heating element, which provides a predeterminable current for the circuit of the heating element (6, 16).

Inventors

• WEBER, ROLF

Assignees

• Siemens Mobility AG

Dates

Publication Date

20260513

Application Date

20241107

Claims (3)

1. Light signal (2) for controlling a means of transport, in particular a rail vehicle, comprising: a) at least one luminous point defining a volume in which a light source (4) associated with that luminous point is arranged; b) a front glass (8) that limits the volume in the direction of emission and is transparent to the light from the light source, c) a heating element (6, 18) arranged in the volume and/or in the front window (8); and d) a control circuit (12) for supplying the light point (4) and the heating element (6, 18) with electrical power, wherein a constant current source (32) is provided for supplying the heating element, which provides a predeterminable current for the circuit of the heating element (6, 16).
2. Light signal (2) according to claim 1, characterized by the fact that At least two light points are provided, with the heating elements of the at least two light points connected in series.
3. Light signal (2) according to claim 1 or 2, characterized by the fact that the control circuit (12) is set independently of the light source used to a power consumption that provides a current for the operation of an incandescent lamp with a predefinable luminous intensity, whereby, due to a possibly lower power consumption by the light source (4) compared to the incandescent lamp, the excess power can be consumed in the heating element (6, 18).

Description

The present invention relates to a light signal for controlling a means of transport, in particular a rail vehicle. Light signals are widely used to control traffic flow, such as in rail and road traffic. Depending on their location, traffic lights, for example in mountains and Nordic countries, are often exposed to very long periods of winter weather. Wet snow, in particular, can obscure the light of a signal due to snow hanging from the barge and/or snow directly on the windshield, preventing it from being seen clearly and early enough. In the worst-case scenario, this can even lead to a vehicle passing a red-light railway signal, with the associated safety hazards. Very often, the individual light points are designed so that the light source of each light point is located in a relatively well-sealed volume. Incandescent lamps, which typically have power consumption of 10 to 50 watts in railway applications, generate a comparatively large amount of heat, which is usually sufficient to warm the front lens of the light point from the inside. This makes it difficult for windblown wet snow to adhere to the outside of the lens. Furthermore, the heat rising from the lens also warms the protective cover above the light point against precipitation, thus virtually eliminating the risk of snow overhanging the lens and obscuring the light point. For reasons of longer lifespan and low maintenance, more and more lighting points, especially in railway signals, are being equipped with LEDs, which require significantly less electrical power to achieve the same brightness. Furthermore, the heat generated by an LED is also considerably lower than that of a traditional incandescent bulb. Thus, the problem of sufficient visibility of light points in winter weather conditions, especially blown-in wet snow, is once again virulent, as the heat generated by the LED light source may no longer be sufficient to keep the windshield and the visor free of snow. Precisely because traffic signals in railway and road areas are exposed to the elements, and deposits of snow, ice, or frost on the surface of the signal lenses can impair visibility, separate signal heaters are used to reduce these safety-relevant impairments. These heaters, in the form of electric heating elements (ohmic resistors), are installed, for example, in and/or on the surface or inside the housing of a signal. These heaters are powered by an electrical supply. A particular challenge here is determining the number of individual light points that need to be heated at a signal location, as well as the distance of the electrical supply to the signal location. In railway signals, all light points are necessary to determine the signal aspect. Therefore, either all light points must be heated, or none at all, as otherwise the signal aspect could be misinterpreted. For this reason, the signal heaters of individual light points are connected in series, so that the failure of a single heater affects all light points and thus prevents any misinterpretation that could jeopardize signal safety. Connecting resistive loads in series presents a challenge for the design of the signaling system's power supply. This is especially true given that signal locations are often far from the actual power supply (railway technology: the technical room can be several kilometers away from the signal location). This also makes the conductor resistance, particularly the ohmic resistance of the supply line, relevant as a voltage divider. This problem has previously been addressed in railway systems by providing a conventional power supply in the technical room, using a transformer with different voltage ratings and additional series resistors. This allows the necessary voltage to be set for each signal location, especially when a variable resistor is also used. This type of power supply requires individual consideration of each location, the number of light points, and the length of the existing cable to the signal location. The present invention is therefore based on the objective of providing a light signal whose light points can always be reliably perceived using simple measures, even in winter weather conditions. The problem is solved according to the invention by a light signal for controlling a means of transport, in particular a rail vehicle, comprising: a) at least one luminous point that defines a volume in which a light source associated with that luminous point is arranged; b) a front panel that limits the volume in the direction of radiation and is transparent to the light from the light source, c) a heating element arranged in the volume and/or in the windshield; and d) a control circuit for supplying electrical power to the light point and the heating element, wherein a constant current source is provided for the supply of the heating element, which provides a predeterminable current for the circuit of the heating element. In this way, it is possible to keep the windshield and/or the