Patent GB-321091-A (GB)
Title: Improvements relating to automatic light changing mechanisms for lighthouses
IPC: F21V19/04
Filed: 1928-12-10
Abstract: 321,091. Austinlite, Ltd., and Walker, C. B. Dec. 10, 1928. Convertible gas and electric lamps; mounting electric lamps in lanterns.-In a light-house lamp in which in the event of failure of an electric light another electric light or a gas light is automatically brought into action, the lights are carried by a horizontal table which is adapted to be rotated in one direction by means of a coiled spring, or a falling weight, under the control of a fluid dash-pot supplied with oil or other fluid by means of a pump, reverse motion of the table and the rewinding of the spring or weight being effected by causing the dash-pot to operate as a fluid motor. In the form shown in Fig. 2, a gas regulator 33 and supports 32 for a pair of electric lamp bulbs 16, 17, Fig. 4, in series with fuses 20, are carried on the upper side of a table b which is secured to a hollow spindle a, segmental contact pieces e for controlling the electric lamp circuits being secured to the lower surface of the table. A weight i for rotating the table is carried by a cord or cable g which passes over a guide pulley h and is attached to a pulley f on the spindle. The spindle also carries a circular block j provided with a radial vane k, Fig. 1, which closely fits a flat dash-pot cylinder 1 provided with a partition m and with an aperture o communicating with an annular reservoir n. The cylinder and reservoir n are connected by pipes to a pump t, adapted to be driven by an electric or other motor z, and to a hollow valve q which is controlled by a spring y and contains a ball valve w controlled by a spring x. The table is held in predetermined positions by means of a pivoted lever 9 engaging the notched periphery of a plate 5 which is connected to the spindle a through the medium of a coiled spring 10 which is housed within a cylindrical wall 11 on the plate. The wall 11 has upper projections which engage slightly larger notches in a plate 34 secured to the spindle a so that the spring 10 can have a further cushioning effect when the table b is arrested by the lever J. This lever forms part of a resilient contact piece 14 which is held against the adjacent segment e by an electromagnet which comprises a series winding 21 and an auxiliary winding 22 and forms part of the electric circuit shown in Fig. 4. Upon failure of the bulb 16, or of the current supply, the electromagnet releases the contact 14 and the circuit is opened by a spring 36, Fig. 2, which acts urpon the lever 9 to release the plate 5 and allow the table b to be rotated against the action of the dash-pot. A projection 23 on one of the segments e connected to the bulb 17 then engages a contact 24 to close the circuit of the winding 22. If the bulb 17 is intact, and the current-supply still working, the electromagnet engages the contact 14 with the adjacent segment e to close the circuit of the bulb 17. A small additional rotation of the table releases the projection 23 from the contact 24 and the lever 9 engages the next notch in the plate 5 to bring the table to rest. If the bulb 17 is defective, or the current supply still not working, the table continues to rotate until a projection 37 on the exterior of a mercury seal d carried by the spindle a operates a lever 38 and opens a gas valve to allow gas to flow, through pipes c within the spindle a, to the gas lamp which is ignited by a constantly burning pilot flame. Also, a signal may be operated to give a warning that the electric light is not in action. At the same time an extra segmental contact 18 on the underside of the table engages a second resilient contact piece 15, and two contacts 26, 27 on the table touch a pair of resilient contacts 28, 29 in the circuit of a shunt winding 30. After the bulbs 16, 17 have been replaced, or the current supply re-established, current flows through the lamps and a switch 8 opens the circuit containing the winding 22 and closes the circuit containing the motor z. The pump t then rotates the table in the reverse direction until it reaches the initial position. A projection 4 on the plate 5 then strikes a tappet 6 and trips a catch lever 7 which operates the switch 8 to open the circuit of the motor z and close the circuit of the winding 22. A slight overrun of the table is allowed so that a projection 31 can touch the contact 24 whereby the winding 22 will close the contact 14 on the segment e and establish current through the bulb 16. The table is finally brought to rest by the arm 9 engaging the plate 5 and with the projection 31 out of contact with the contact 24.