GB384029A - Improvements relating to traffic-control signals - Google Patents

Abstract

384,029. Electromagnetic switches. QUILLIAM, S. T., 4, Longford Road, Stretford, near Manchester, and HARRIS, G. G. R., 64, Milden Road, Sheffield. Oct. 15, 1931, No. 28613. [Class 38 (v).] In automatically changing traffic control signals failure of the signals to act properly within a predetermined time limit causes a warning circuit to be closed, the signals to be put at " caution," and, if desired, the main electric circuit to be broken. The emergency contacts are adapted to be operated by a weight 2 which normally keeps rising and falling without reaching its upper limit. The weight 2 is carried by a cord 3 wound on a pulley 4 geared to a disc 1 driven by an induotion coil 5 which is in connection with the ordinary signal control mechanism by wires 6, 7, and through a wire 8, contact 9, and pivoted contact 12 with a terminal 13. When the parts 9, 12 are in contact, which only occurs between signals or when the signal system continues improperly, the coil 5 is energized and the weight 2 is raised, and if time permits, the weight continues to rise until it engages the pivoted member 14, thereby opening contacts 16, 18 and breaking the circuit of the controlling mechanism. If the weight 2 rises still farther it closes contacts 20, 21 and completes the circuit of a warning device. Assuming the weight 2 to be in an intermediate position and the amber light in operation, the circuit for the amber light includes wires 25, electromagnet 24, pivoted lever 27, contacts 28, 29, and wire 30. The contacts 9, 12 being broken by the electromagnet 24, the weight 2 falls. If'the amber light operates beyond its normal period, the weight 2 falls to the position shown in Fig. 1 and so forces the lever 10 away from the core 24, closing the contacts 9, 12, thus causing the weight to rise. In a modification, a rotatable switch-operating arm replaces the weight. In another modification, Fig. 3, when the signal light is operating, a plunger 41 is pulled inwards by a coil 42, and a tube 35, pivoted at 36, is tilted to the right, but when the coil is de-energized, the tube tilts by gravity to the left and if time permits, or the amber light, for example, does not operate within a normal period, the mercury in the tube, flowing through an aperture in a bridge 38, bridges contacts 39, 40 and closes a warning circuit.