334,928. Reyrolle & Co., Ltd., A., Linstow, F. N., and Wright, H. May 13, 1929. Road signals. - In road-traffic signalling apparatus of the kind controlling traffic at cross-roads from a tower, the durations of two signals may be independently adjusted by means of movable stops controlling the times at which the rotation of an electric motor is periodically reversed. The signals may be semaphore arms &c., having coloured spectacles for use at night, or, as described, banks of lamps (red, R, amber, A, and green, G) installed at the north-south and east-west, roads of a crossing. The signals may be operated by solenoids D, D<1>, D<2>, Fig. 1, selectively energized through contacts c, c<1>, c<2>, closed by cams B<1>, B<2>, B<3>, integral with a drum B driven through gearing A<3>, A<4> by a motor A<2>, the motion of the drum being reciprocative about the position shown in Fig. 1, while the rotation each side of the central position is adjustable by movable stops L, L<1>, which enable the motor to be periodically reversed at the requisite times. As shown diagramatically in Fig. 1, the contacts c<1> are closed and the solenoid D' energized to close a switch E to light the amber lamps of both the N-S and E-W signals. With the drum rotating in the direction of the arrow, the contacts C<2> are closed to energize the solenoid D<2>, which however cannot operate to close the switch E', until the interlocking lever G<1> is released upon de-energization of relay D', owing to the overlapping of the cams B<2>, E<3>. The lighting of the green of the N-S, and the red of the E-W signals respectively, thus follows instantaneously the extinguishing of the amber lights. These signals remain during the further rotation of the drum, during the reversal of its rotation, and until the central position is reached, when the above operations are reversed, so that when the cam R<2> again releases the contacts c<1>, the energized relay D closes its switch E', E<2>, to light the red of the N-S and the green of the E-W signals. These signals remain while the drum is rotating and returning to its central position when the signals cycle is re-commenced. Reversing the motor. In the diagrammatic representation, Fig. 1, if the drum shaft A<1> is rotating in the direction of the arrow, the bevel pinion J is rotated similarly, driving through the pinions J<2>, loosely mounted on the arms K pivotable about the shaft A<1>, a bevel wheel J<1> in the opposite direction. The wheel J<1> continues to rotate until its pinion J<3> abuts against the arm L<1> stopping its progress and causing the pinion J<2> to rock the arm K from the stop K<1> to the stop K<2>, the movement of the upper end of the arm K being arranged to actuate a reversing switch H for the motor. The motor then rotates in the opposite direction, driving the wheel J<1> so that its pin J3 moves towards the arm L which when struck again cause the motor to be reversed. Arms L<4>, L<5> movable over a dial M<1> indicate the positions of the corresponding arms L, L<1>. Reversing-switch and setting-mechanism. The bevel pinions J, J' above referred to are replaced by ordinary pinions J<4>, J<6>, meshing with pinions J<6>, J', which mesh with one another, and are mounted on the pivotable arm K balanced by a weight K3. A compression spring N is mounted on knife edges N', N<2>, the former being integral with a lever O fixed to an arm 0' adapted to rock between stops O<2>, O<3>, and the latter with an arm K', integral with the arm K. In the position shown, with the arm K against the stop K<2>, the lever 0 is forced away from the motor reversing switch contact H<1> which is pressed against a contact H<2>. When the motor has rotated to rock the arm K to the stop K<1>, by means of the pin J<3>, the knife edge N<2> passes across the centre line between the pivot of the arm O<1> and shaft A<1>, causing the spring N with snap action to force the contact H' against the contact H<3>, thus reversing the motor. Modified forms of apparatus. To enable a vehicle driver to know which signal is to follow the amber light, the red and amber lamps together are lit for a short period before changing for green. To accomplish this the drum B has five contacts, Fig. 3, controlling five solenoids D<1> D<3> - - D<6>, the red lamps of the N-S and E-W signals being in series with windings P, P<1>, of normally closed relays p<2>, P<3>, which cause the red and amber of the N-S to be alight for a short time with the amber only of the E-W signal, followed by the red, and then the red and amber of the E-W simultaneously with the green only of the N-S signal. In another modification, Fig. 4, to accomplish this sequence of signals, the drum B is displaced by two arms T, T<1> fixed to the shaft A<1> operating switches S, S<2> respectively carrying arms S<3>, S<4> to operate a switch S. In the position shown the red of the N-S and the green of the E-W signals are alight, the motor has just reversed and the shaft A<1> is running as indicated by the arrow. The arm T<1> first moves the switch S<2> opening its contacts V<1>, V<3> and closing V, V<2> thereby extinguishing the green of the E-W signal and lighting both amber lamps, both the red and amber of the N-S signal being now alight. Further rotation of shaft A<1> causes the arm T to operate S which, by means of an arm S<3> carries the switch S' with it, closing contacts V, V<2> of these switches, whereupon only the green of the N-S and the red of the E-W signal are alight. The shaft A now reverses and the arm T operates the switch S extinguishing the green of the N-S signal and lighting both amber lamps, the red and amber of the E-W signal being now alight. The arm T<1> next operates the switch S<2> which by means of its arm S<4> carries the switch S with it, thus completing a cycle of operations. The construction of the switches S, S<1>, S2, ie shown in Figs. 5 and 6. A switch S, or S<2>, Figs. 4 and 5, comprises frameworks U, U<1>, carrying the fixed contacts V, V<1>, a bell-crank lever W adapted to be rocked between stops U<3>, U<4>, by the arm T actuating the coaxially pivoted arm U<2> carrying the contacts V<2>, V<3>, by means of a snap-action spring W<2>. The switch S<1>, Figs. 4 and 6, is similar to S, S<2>, but has a spring W<6> connected from the pivotal arm U<2> to a fixed stop X to assist in the actuation of the arm U<2> after the latter has been rocked just past the dead centre position by either of the arms S<3>, S<4> of the corresponding switches S, S<2>. When the automatic apparatus is not in use the motor is stopped with the amber lamps " on " and the switch Z opened to extinguish whichever red lamp is " on."