FR2485460A1 - Optical monitor for railway crossing - triggers delayed action signal and optical protective sheet renewal after longer set delay following obstacle detection - Google Patents

Abstract

The railway crossing has an array of optical infrared transmitters and receivers for detecting the presence of an obstacle on the crossing. Each of the transmitters and receivers (11) is protected by a transparent plastics ribbon which can be wound from a call, across the optics and onto a take-up roll by a motor (M) to present a clean portion to the optics when the previous portion is dirtied. The receivers are coupled to an AND gate (E) whose output supplies a first time delay typically of 50 seconds. This indirectly switches a relay (F) activating a train signal and also triggering the motors through a further delay circuit (B) of typically 8 secs. The second delay circuit is switched by a first contact of a second relay (R) controlled directly by the first delay circuit. The first relay (F) is switched by a further delay circuit (C) after a 10 second delay, the further circuit being controlled by a second contact of the second relay.

Description

Device for unwinding protective ribbons for infrared barrier optics for level crossings
The present invention relates to a device for unwinding protective tapes of infrared barrier optics for level crossings and in particular an electromechanical device ensuring the protection and automatic cleaning of lenses and / or mirrors of optical devices used to detect an obstacle immobilized on a level crossing.

We know that it is necessary to stop trains when a road vehicle accidentally stops on the road between the two barriers delimiting a level crossing. For this, light barriers are used comprising light ray emitters, receivers and possibly mirrors for returning light rays to the receivers and based on the principle of the interruption of the light beams, this interruption causing the start-up railway vehicle stop signals.

However, it can happen that the interruption of the light beams is caused by dirt deposits on the optics and which are due to spray, dust or projections from road and rail vehicles. Known protection devices with plastic ribbons and their unwinding in front of the optics are then used in order to replace dirty surfaces with dirty tape.

 However, the devices of the prior art are based on a periodic renewal of ribbons by means of a timer.

The disadvantage of these devices lies in the fact that they require a prohibitive consumption of ribbons and therefore a replacement and a supply requiring frequent visits of personnel for the renewal of ribbons.
The device according to the present invention overcomes this drawback. In this in fact the unwinding of the ribbon is discontinuous and takes place only when a vehicle is immobilized for a relatively long period between the two barriers of the level crossing or when the ribbon is dirty.

 The subject of the present invention is a device for unwinding protective tapes of the infrared barrier optics for level crossing comprising transmitters and receivers of infrared beams between which an obstacle stops the beam, motors unrolling a transparent ribbon in front of each of the optics of the transmitters and receivers, said receivers supplying the inputs of an AND gate, the output of which supplies a first time delay at the fall of a duration TA, said first time delay indirectly triggering a first relay actuating the signaling lights of trains, said motors being supplied through a timer, characterized in that said timer TB is triggered by a first contact of a second relay supplied directly by said first timer and that said first relay is actuated by a second timer at the fall in duration T triggered by a second contact of said second relay, the duration T B being slightly less than the duration Tc itself less than the duration TA.

 With reference to the attached diagrammatic figures 1 to 5, an example of implementation of the present invention will be described below, an example given purely by way of illustration and in no way limiting. The same elements bearing on all the figures the same references.

 Figure 1 shows a schematic plan view of a level crossing with light barriers.

 FIG. 2 represents a schematic view of the mechanism for unwinding the protective tape in front of the optics of the dam.

 FIG. 3 represents an electrical block diagram of the control of the signaling lights and of the motors for unwinding the protective tapes.

 FIG. 4 represents diagrams of the logic states of the various components of FIG. 3 in the case of the presence of an obstacle on the level crossing and of the absence of dirt on the protective tape.

FIG. 5 represents diagrams similar to those of FIG. 4 in the case of the presence of dirt on the protective tape and the absence of an obstacle on the level crossing.

 As can be seen in FIG. 1, two railways 1 and 2 are cut by a roadway 3 which includes barriers 4 and 5 for level crossing. Transmitters such as 6 and 7 of infrared beams cooperate with receivers of these beams such as 8 and 9. In the case of a transmitter 6 and a receiver 8 arranged on the same side of the roadway 3 there is a mirror 10 arranged on the other side and returning the beam to the receiver 8. The transmitters and receivers are arranged in sufficient number to cover the whole of the raised 3 between the two barriers 4 and 59 in order to detect a stationary vehicle. active mirrors 10, transmitters 6 or 7s receivers 8 or 9 which we will call optical 11 is protected by a transparent ribbon 12 of plastic material (for example nylon) (FIG. 2).

 The ribbon 12 is stored on a supply reel 13 to be wound up under the action of a motor M not shown, on a take-up reel 14. thus when the motor turns the parts of the ribbon 12 exposed to dirt are replaced by clean parts and the propagation of the infrared beam is again restored.

 The electrical device according to the invention is particularly detailed in FIG. 3. The ribbon, as will be seen below, only scrolls discontinuously on reduction of the receiver output signal and the control of the signaling lights is not carried out. not only if the tape is dirty.

 We see in Figure 3 a plurality of optics 1 1 consisting of transmitters, receivers and possibly mirrors, which are associated with ribbons as shown in Figure 2 moved by motors M. The infrared receivers forming part of the optics 1 1 deliver electrical signals to an AND gate, E when the infrared beams from the transmitters are not interrupted.

When one of the beams, for example, is interrupted, the electrical signal for entering logic state 1 goes to state O and gate E delivers a state 0. The output of gate E attacks a time delay on falling A of duration TA The contact of time delay A is delayed at fall, that is to say that the contact does not move until after a time delay, the start of which begins with the interruption of the current in the time delay coil. On the other hand, an attraction for the duration of the delay time TA causes an instantaneous action to restore the current. The duration TA can be 50 seconds.

This duration is imposed by the duration of immobilization of the obstacle on the level crossing because it is not useful for the passage of vehicles which do not stop to trigger the signaling lights or the starting of the engines. MTa time delay A triggers a relay R whose contacts are represented in the normal state when A is in logic state 1 as well as the relay R.

A contact 14 is a normally open contact which has the characteristic of being open when the relay is energized. The contact 14 is connected to a timer B of duration TB which may be 8 seconds. your timer B is an organ, which when activated, closes a contact for a given time and opens it automatically at the end of this time. The timer B, when it operates for the duration Tg, powers all of the motors M of all the optics 11.

 Contact 15 is linked to a time delay at fall C of duration TC greater than TB. The TC duration can be 10 seconds. The time delay C activates a relay F which in the normal position activates a contact lighting the green signal (V) for passing and in the de-energized position the red signal (r) for stopping the trains.

In Figures 4 and 5 we see the successive diagrams of operation at the output of the door E, E; timer A, A of relay R, R; timer B, B; motors M, M; timer C, C; of relay F, F.

In FIG. 4, the passage from E from state 1 to O means that there is an interruption of the infrared beam either because of an obstacle or because of dirt. Maintaining in Figure 4 E in the state O means that there is an obstacle - a stationary vehicle and not a dirt on the tape.

 In fact, the time delay A is activated by the passage from E to O and is triggered after 50 seconds also passing to O. The relay R is de-energized and goes to state 0 which has the effect of firstly triggering the timer B (state 1) for 10 seconds as well as to operate the motors M and on the other hand to activate the time delay C (dotted line) which has the effect of changing C from 1 to O after 10 seconds as well as F from 1 to O (Red).

 In FIG. 5, the passage for E from O to 1 means that the beam is restored and that there has been dirt on the tape and no obstacle.

 It follows that A, triggered as in FIG. 4 and passing to state 0, returns to state 1.

 It is the same for relay R. The timer B and the motor M operate for 10 seconds which has the effect of unwinding the strips of all the optics and re-establishing the beams between transmitters and receivers. Time delay C remains at state 1 because its starting by the dotted line (change of state from R from 1 to O) does not trigger an effect since R goes from O to 1 so becomes again excited before the end of the delay time TC.

 it follows that F remains in state 1 and does not trigger the stop signal.

It can be noted that a fugitive obstacle lasting less than TA (50 seconds) does not change the state of relay R. The signaling lights are therefore triggered after 60 seconds (TA + TC).

Furthermore, the use of electromechanical devices such as relays and timers is not limited. it is obvious that static components, known to those skilled in the art, can replace these by having the same function to have the same result.

 The applications of the device according to the invention are in the field of railway signaling.

Claims (1)

CLAIM Device for unwinding protective tapes of infrared barrier optics for level crossings comprising transmitters and receivers of infrared beams between which an obstacle stops the beam, motors unrolling a transparent ribbon in front of each of the optics of transmitters and receivers, said receivers supplying the inputs of an AND gate, the output of which supplies a first time delay at the fall of a duration TA, said first time delay indirectly triggering a first relay actuating the signaling lights of trains, said motors being supplied by means of a timer , characterized in that said timer TB is triggered by a first contact of a second relay supplied directly by said first timer and that said first relay is actuated by a second timer at the fall in duration TC triggered by a second contact of said second relay , the duration TB being slightly less than the duration T C itself less than duration TA.