GB440906A - Improvements in and relating to road traffic signals - Google Patents

Abstract

440,906. Road signals for controlling traffic. KENT, A. F., Lee Moor, Cornwood, Devon. Sept. 26, 1934, No. 27577. [Class 118 (ii)] A pedestrian-controlled road-traffic signal comprises an arm which can be lowered from a vertical to a horizontal position, the sign on the arm changing as the horizontal is reached from a " caution " to a " stop " sign, the arm restoring slowly and being arranged so that re-operation is not possible until the signal is again vertical. The changing sign may be (i) a drum bearing red and green reflectors and adapted to be rotated to show red and green in rapid succession while descending to the horizontal position ; (ii) a prismatic unit having "slow" on two sides and " stop " on the other two which unit is rotated to present the "stop" signs to the traffic as the horizontal is reached or (iii) a " stop " sign normally hidden by a " slow sign, the " slow sign being held whilst the " stop sign is lowered to the horizontal as shown in the drawing. When the signal is at " stop " a "cross now " signal may be given to pedestrians. The sign may be fitted with internal illumination or with mirrors which reflect external light through the signs. As shown, when the " stop " signal is to be given the weighted or spring driven lever f is raised into the position shown either by handle l acting on pin m or by other suitable means. When the signal arm is vertical the cam c on lever a, which is rigidly connected to the signal arm spindle b, presses the pawl h anticlockwise against the action of spring j so that it engages pin d on lever a. The lever f restores slowly and as pawl h and pin d are engaged, the lever a is turned through 90‹ into the lower position shown dotted. Before reaching the horizontal position the " slow " signs are held and the " stop sign, which is normally hidden, moves alone into the horizontal position. When the lever a is in its lower position the cam c moves away from the pawl h so that the spring j swings the pawl clockwise and pin d is released. The lever a and the signal arm then restore slowly, the restoring power being supplied by a spring, whilst the action is delayed by a dashpot (not shown). Should the lever f be again lowered before the apparatus is normal the cam c will not move the pawl h into engagement with the pin d and the signal arm will not be affected.