US2300613A - Street traffic control system - Google Patents

Description

NOV 3, 942- E. J. COLLE 2,300,613

STREET TRAFFIC CONTROL SYSTEM Filed May s1. 193s "LIGHT PHTO ELECTE /C CE' L L5 Bf@ L/s/fr sou/ac:

Patented Nov. 3 1942 T OFFICE STREET TRAFFIC CONTROL SYSTEM Edouard Joseph Colle, Antwerp, Belgium, assignor to International Standard ElectrlcrCorporation, New York, N. Y. l

' Application May 31, 1939, serial No. 276,628 In Belgium June 4, 1938 1 claim. (ci. 177-337) The invention relates to improvements in or relating to street trailic control equipment of the trado-actuated type. 4 Previous systems of traio operated control equipment comprised road contacts or studs embedded in the roadway near a crossing, these contacts or studs being operated each time a vehicle passed over them. Upon the operation of a contact an impulse is transmitted to a controller which registers the number of vehicles passing towards the crossing over each roadway leading thereto and so determines how the trafic lights are to be operated. A

Such systems have the disadvantage that the detectors embedded in the surface of the road are subject to heavy wear and consequently have to be frequently renewed.

The object of the invention is to provide a trafc operated system which is not subject to heavy wear due to the passage of trafc over essential parts of the control system.

According to the main feature of the invention each roadway leading to a crossing is provided with two light-sensitive cells which are mounted at a short distance apart on one side of the roadway, are arranged to be actuated by beams of light directed on to them from a lamp or lamps mounted on the opposite side of the roadway, and'control recording means arranged to differentiate between interruption of the lightbeams in different ways. It is to be understood thatthe terms light and light-sensitive devices are to be interpreted as including infrared rays and devices responsive thereto.

The invention will be fully understood from the following description of the accompanying drawing which shows a four-road crossing provided with four sets of signals and four sets of tramc-operated control equipment.

The sets of equipment associated with each roadway are identical and the operation of one set of equipment only will bedescribed in detail.

Situated on the right hand side of the road A approaching the crossing is a lamp standard AL which may comprise either a single lamp arranged to direct beams of light on to each of the photo-electric cells mounted at PAI and PA2 o r two lamps each of which is arranged to direct a beam of light on to either PAI or PA2. .The lamp and cells are mounted at such a height above the ground that when a vehicle passes along the roadway the beams of light impinging on the photo-electric cells are interrupted.

'Ihe arrangement of the photo-electric cells the right hand side of the roadway will interrupt both the beams of light for a period whilst vehicles passing along the left hand side of the road will interrupt first one beamfof light and then the other beam of light but will not interrupt both beams at any one time. In this manner the position of the vehicle with respect to the width of the road is determined. l

Each photo-electric cell is arranged to control a relay in a chain of relays at the traffic control cabinet TCC.

If the relays controlled byphoto-electric cells PAI and PA2 are operated simultaneously then the traiilc controlling register device at TCC registers the fact that avehicle has passed along road A towards the crossing. If, however, the relays controlled by PAI and PA2 do not operate simultaneously it is not possible to operate the register device and hence vehicles proceeding along the side o the road opposite to the lamp do not eiect the controller.

Vehicles proceeding towards the crossing along the other roadways leading to the crossing, ef,- fect the photo-sensitive devices BL, PBI, FB2; CL, PCI, PC2, and DL, PDI, PD2 associated with these roadways in like manner and according to the ow of traffic along the roads the traftlc lights TLA, TLB, 'I'LC and TLD are operated.

If it is not possible to arrange the lamp and photo-electric cells to have a large angle between the beams directed across the roadway, the relays controlled by the photo-electric cells can be so interconnected that the order in which the beams of light are interrupted determines whether the register device makes a record of a vehicle passing towards the crossing or not. For example a vehicle passing along the right hand side of the road towards the crossing will rst interrupt the beam of light between AL and PAI and then the beam of light between AL and PA2. This order of interruption of the light beams ensures that the vehicle is registered as proceeding towards the crossing. If, however, a vehicle passes on the right hand side of the roadway away from the crossing then the beam of light between AL and PA2 is first interrupted followed by the beam of light between AL and PAI. This order of interruption is arranged to have no effect on the register device.

Both the housings for the lamps and the photo-electric cells are provided with screens arranged to prevent daylight and direct beams of light, due to the sun or due to car headlights,

and lamp is such that a vehicle passing along tem.

from interfering with the operation of the sysphoto-sensitive devices to produce dverging beams of light falling on respective ones of said photo-sensitive devices, and a relay operative in response to interruption of both of said beams of 5 light during the same interval, whereby vehicles passing said light source on the side of the street adjacent thereto will operate said relay, while vehicles passing said light source on the side of the street adjacent said photo-sensitive devices 10 will not affect said relay.

EDOUARD JOSEPH COLLE.

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