WO1997008035A1

WO1997008035A1 - Device for monitoring and controlling of rail based vehicle

Info

Publication number: WO1997008035A1
Application number: PCT/NO1996/000212
Authority: WO
Inventors: Thorbjørn BEKKEN
Original assignee: Aeg Norge A/S
Priority date: 1995-08-29
Filing date: 1996-08-27
Publication date: 1997-03-06
Also published as: AU6890996A; NO953385L; NO953385D0; NO305642B1

Abstract

A system, transmitter and receiver for the supervision and control of a railbound vehicle where a transmitter feeds a low frequency, pulse modulated signal current into the rails corresponding to certain allowed speed limits for the vehicle. A phase generating device (11) transmits signals having a phase shift of zero and/or where at least a portion of the signal contains phase shift. The phase shift may, e.g., be 180°.

Description

Device for minitoring and controlling of rail based vehicle

The present invention relates to a device for the supervision and control of railbound vehicles ofthe type described in the preamble in claim 1.

Various systems for the supervision and control of railbound vehicles have been used the world over, but one which has become very widespread in the last 30 to 40 years is an analog code system which has been developed for supervising the speed of railbound vehicles. This system makes use of a low frequency, pulse modulated signal current which is fed into the rails. These signals contain a code which, e.g., can indicate maximum speed by means ofthe fixed codes. A code sequence of this kind may be as follows:

Unmodulated < 15 km/h

75 pulses/min < 30 km/h

120 pulses/min < 50 km/h

180 pulses/min < 70 km/h

270 pulses/min < 90 km/h

A previously known analog system of this kind has a clear limitation with regard to the number of possible codes.

Among the efforts to solve this problem in the USA, there has been an attempt to introduce more codes by supplying the intervals ofthe modulated signal current with 120 Hz. However, this is a relatively costly solution since, besides new code device, there is also a need for frequency converters of 120 Hz in addition to the existing ones.

The objective ofthe present invention is, in an inexpensive manner, to be able to make use of this old system and at the same time obtain a code system which can provide intermediate velocity steps in addition to those mentioned above.

This is accomplished by means of a device ofthe aforementioned type, the characteristic features of which are disclosed in claim 1. Additional features ofthe invention are disclosed in the remaining dependent claims. Thus, by means ofthe present invention a device is provided which allows wagons having old equipment to run on the old system at the same time as new wagons, or converted old vehicles, with the additional velocity steps.

The invention will be described in more detail below with reference to the drawings, wherein:

Fig. 1 is a schematic illustration of a code transmitter device and two receiver devices.

Fig. 2 is a block diagram of a code transmitter according to the present invention.

Fig. 1 is a schematic illustration ofa code selector 1 and the actual code transmitter 2 which emits pulse signals into a railway line. Furthermore, a wagon ofthe old type is shown where 4 denotes the receiver unit for a wagon unit, and 3 a display device for displaying the transmitted signals. The reference numerals 3' and 4' indicate respectively the display device and the code receiver on a wagon which is equipped with a code system according to the present invention. On wagon 4 there are indicated two waveforms transmitted into the signal track: the uppermost shows signals transmitted with no phase shift, whilst the lowermost signal form shows signals transmitted with a phase shift after a certain time. The display device 3 in Fig. 1 shows how an old wagon will display the two different signals transmitted into the track, the uppermost showing a speed of 30 km, and the lowermost also showing 30 km despite the fact that the signal has had a partial phase shift.

Fig. 1 shows a wagon equipped with the new system according to the present invention, and here in the display panel 3' it can be seen that on a partial phase shift the speed will be increased to 40 km.

These speed limits can also be used to control the wagons so that it is not possible to exceed the at all times registered speeds transmitted into the rail network from the speed selector.

Fig. 2 is a schematic circuit diagram ofthe mode of operation ofthe safety system according to the present invention.

If the safety system 1 selects velocity steps 30, 50, 70 or 90 km/h, which correspond to, e.g., the velocity steps ofthe previously known system, the code selector 12 in the code transmitter 2 will select corresponding codes. The code selector then transmits output signal PH-0, corresponding to no phase shift, to a phase generator 11 and a triac 6 is switched on and off in time with the selected code so that the transformer 7 supplies pulsating 75 Hz between PH-0 and the central tap 13 ofthe transformer 7. A coded signal current is then transmitted via a resistor 8 and a transformer 9 into, e.g., a railway line 5.

However, if velocity steps 40, 60, 80 or 100 km/h are selected by the safety system 1 in addition to the aforementioned speeds, a second sequence is produced. Some 50 to 65 ms after each pulse start, a phase signal PH-180°, i.e., a signal which is shifted 180° in phase, is transmitted to the phase generator in addition to PH-0. When the phase signal arrives, the first triac 6 will be switched off and a triac 10 will then be switched on. The phase generator 1 1 ensures that the triac 1 and the triac 2 cannot be switched on simultaneously. During the time the triac 6 is switched on (about 55 ms), the transformer 7 is fed between PH-0 and the central tap. In the remaining pulse length, the triac 6 is switched off, the triac 2 is switched on and the transformer 7 is fed between PH-180⁰ and the central tap 13. This means that the signal current in the track, apart from about the first 55 ms, has been shifted 180°.

The codes which are transmitted into the track are intercepted by inductive antennae which are located underneath the wagon, ahead ofthe first bogey.

A receiver is coupled to the inductive antenna in order to detect the signals and conduct them further for processing and display, or optionally for controlling the speed ofthe railbound vehicle.

The receiver first detects the number of pulses per minute which corresponds to the speed indicated by the code switch. A check is then made to see whether portions ofthe pulse contain a phase shift. This is done in the first 110 ms or so ofthe code pulse. If there is a phase inversion the speed can, e.g., be increased by 10 km/h.

Claims

P a t e n t c l a i m s

1.

A system for the supervision and control of a railbound vehicle wherein a transmitter feeds a low frequency, pulse phase modulated signal current into the rails corresponding to specific allowed speed limits for the vehicle, and where there is provided a receiver in the railbound vehicle to register the transmitted pulses, characterised in that there is provided a phase generating device (11) for the transmission of a pulse train wherein at least some ofthe pulses in the pulse train contain phase shift.

2.

A system according to Claim 1 , characterised in that the phase shifted pulse portion has a phase shift of 180°.

3.

A system according to Claims 1-2, characterised in that the first portion which is not phase shifted has a duration of between 50 and 65 ms, preferably 55 ms.

4. A transmitter for transmitting a low frequency, pulse modulated signal current into the rails corresponding to certain allowed speed limits for the vehicle, characterised in that there is provided a phase generator (11) having a non-shifted phase and a phase shifted outlet connected to respective triacs (6J0), the output signal from the first triac (6) being fed between one terminal on the primary side of a transformer (7) and a central tap (13) and the output signal from the second triac (10) being fed between a second terminal on the primary side ofthe transformer (7) and the central tap (13), and that the secondary side ofthe transformer (7) is connected via a resistor (8) to a transformer (9) which feeds the coded signal current into a railway line (5).

5.

A receiver for receiving low frequency, pulse modulated signal current transmitted into the rails corresponding to certain allowed speed limits for the vehicle, characterised in that the receiver first detects the number of pulses per minute and then detects any phase shifts in portions ofthe received pulses.