Patent GB-299040-A (GB)
IPC: G08G1/08
Filed: 1928-09-29
Abstract: 299,040. Automatic Signal Corporation, (Assignees of Haugh, H. A.). Oct. 20, 1927, [Convention date]. Road signals.-An automatic signalling system for controlling vehicular traffic at highway intersections, railway and other crossings, is operated (a) by the traffic through a timing mechanism, (b) by the timing mechanism, or (c) by both, in such a way that : (1) Right of way is given successively to several traffic lanes in an order which may be predetemiined but in such a way that the length of time during which one lane retains the right of way is dependent upon either the approach of vehicles in said lane, or upon the approach of vehicles in one or more other lanes, or upon both. (2) A traffic line which does not require the right of way cannot hold it to the disadvantage of one which does. (3) A vehicle whose progress is prevented by a continuous stream of opposing traffic may not be required to wait more than a. fixed period of time, but within this period is given right of way for as long as required for itself and following vehicles up to the aforementioned time limit. (4) Interfering lanes of traffic shall not be permitted to hold the right of way simultaneously. (5) A vehicle which has passed the actuating means is protected against opposing traffic for a period of time sufficient to permit the vehicle to pase the intersection of the traffic lanes. (6) A vehicle which approaches an intersection is given immediate right of way on condition and only on condition that there is no opposing traffic in or immediately approaching the intersection. (7) When a vehicle is not given immediate right of wav or has right of way taken from it before it has had sufficient time to reach the intersection. the system is left in such a condition that right of way will return to the delaved car at the earliest possible moment. (8) Continuous vehicular traffic in one line is periodically interrupted to allow pedestrians to cross this lane. (9) When the signal means and timing system is disconnected from the traffic actuated means, right of way is given successively to the various traffic lanes according to a predetermined sequence and each for a predetermined time interval. (10) By simple adjustments in the system all fixed time intervals and responses to traffic in various lanes may be adjusted to meet various distributions and densities of traffic. The traffic control signal device 9 at the intersection of streets A, B may comprise a yellow light 89 which indicates that no vehicles are approaching, green light 85 and red light 86 giving right of way to street A, and red light 84 and green light 83 giving right of way to street B. In place of lights, semaphore arms, horns, bells or other signals may be used. The vehicle-actuated means 4 - - 7 may each comprise a pivoted ramp 104 so arranged that when a vehicle passes over it, contacts 90, 91 are separated and contacts 92, 93 brought together, the effect being to open the circuit beween wires 11, 12 and make a circuit between wires 10, 11. A spring 108<1> rasets the apparatus after the vehicle has passed say the ramp 5, connection between wires 11, 12 being re-established through contacts 94, 95 on the other ramp 7 in street A. Wires 10, 11, 12 interconnecting the ramps 5, 7 also connect with the time-limiting control 8, Fig. 1, which is shown in detail in Fig. 2 and comprises instantaneous operating contact relays 26. 27, 34, 35, 36, interconnected as shown with oil dash-pot relays 28, 29 arranged to operate their apertures thirty seconds after their coils are energized, and oil dash-pot relays 30, 31 arranged to operate their armature ten seconds after their coils are energized, and oil dash-pot relays 32, 33, arranged to operate their annatures two seconds alter their coils are energized. Wires 13, 14, 15 for the ramps 4, 6 on street B correspond to the wires 10. 11, 12 for street A. If, for example. a vehicle approaching from street A has automatically lighted the A-street green and the B- street red lights 85, 86 and simultaneouslv extinguished the yellow light 89, the circuits shown provide for relinquishing the A-street green light under any one of the following conditions : (1) When A-street traffic has all passed the intersection. (2) If A-street traffic is still moving at the end of the thirty seconds the green light is yielded to permit pedestrians to cross A-street. (3) If A-street traffic is still moving at the end of the thirty second period and vehicles are waiting on B-street, the A-street green light is yielded in favour of B-street. The control circuit is so arranged that when A-street has yielded the green light under any of the above conditions, a, yellow light is shown in both streets during a caution period of two seconds. If, at the end of the yellow caution period, vehicles have operated the B-street actuating means since ten seconds before said street last lost the right of way, the green light is given to B-street. If, on the other hand, no vehicles have operated the B-street actuating means since ten seconds before B-street last lost the green light, and vehicles have operated the A-street actuating means since ten seconds before A-street last lost the green light, right of way returns, to A-street after the yellow caution period. If the actuating means in neither street has been operated since ten seconds before said street last lost the green light, the yellow lights will remain lighted on both streets until a vehicle approaches, whereupon right of way is immediately given to that vehicle. The control may be varied by the selective closing of switches 16, 17, 21, 20, 18, 19, 107, 108. Manual control may be effected by the use of switches 105, 106. All signal lights. except the yellow light may be extinguished by closing a switch 102, or by applying power to the two wires marked " To Fire Headquarters," thus providing for emergency control.