Patent GB-216189-A (GB)
Title: Improvements in or relating to rotary light signal apparatus
IPC: G05D16/06
Filed: 1923-02-19
Abstract: 216,189. Gas Accumulator Co. (United Kingdom), Ltd., Watson, A. G., and Goodwin, G. Feb. 19, 1923. Revolving lamps.-In revolving light-projecting apparatus of the type in which gas mixers supplying gas to the burner are adapted to rotate the optical system, two mixers are provided and so interconnected that, should one fail, the other is brought into operation. Provision is alsc made whereby both mixers are brought into operation for a short period each time the optical system commences to revolve. The mixers a, b may be of the type described in Specification 102,374, and each comprises four chambers A - - C, Fig. 4. High pressure gas is supplied at E to the chamber A and leaves at L at a constant pressure determined by an adjustable spring G acting on a diaphragm F which operates the inlet valve J through a bell-crank lever H. Gas leaving at L enters through a port M, the chamber B thereby raising a diaphragm O which operates through a pivoted lever c the lamp-rotating mechanism. The diaphragm 0 carries a diaphragm P, the upward movement of which causes air to be drawn into the chamber C through a non-return valve R. When a determined quantity of gas has entered the chamber B the diaphragm O lifts a valve S, thereby closing the port M and allowing the gas to escape through a port N and mix with the air in the chamber C whereupon the diaphragms 0, P fall, admitting a fresh charge of gas to the chamber B and expelling the gaseous mixture from the chamber C through a valve U, port Y, and valve X to a chamber D. The pressure in the latter chamber is regulated by a spring-influenced diaphragm Z operating the valve X, and its outlet I communicates with the burner. The chamber C of such mixer is provided with an outlet V connected by a pipe v<1>, Fig. 1, valve 4 and throttle 8 to a chamber v closed by a diaphragm p<1>. Bearing on the diaphragm p<1> is a bell-crank lever p adapted to operate a valve o connecting an outlet W from the chamber C of the mixer b to a diaphragmchamber m, the lever p being also adapted to operate a valve 7 in the burner supply pipe. Normally the valve 7 is closed and the valve o open so that on opening the valve 4 to start the apparatus, gas is admitted to the diaphragm-chamber m raising the diaphragm and opening a valve k which admits gas from the mixer b to the burner supply pipe. As the diaphragm p<1> is distended, the valve 7 is opened, and after a predetermined interval sufficient to allow the rotary apparatus to attain full speed, the valve o is automatically closed whereupon the gas in the diaphragm chamber m leaks away through a throttle 9 allowing the valve k to close and cut off the mixer b, the mixer a then taking the full load. The chamber C of each mixer is also provided with an outlet W, one connected to each side of a diaphragm y in a chamber x adapted to operate a valve z admitting gas to the diaphragm-chamber m so that, m the event of the pressure in the mixer a falling off, the mixer b is again brought into operation. The rocking lever c of the mixers are coupled by links u to free-wheel clutches d on a pair of aligned spindles e, the rotary movement thereby imparted to the latter being transmitted to the spindle i of the turntable of the optical system through differential gear f. A non-return freewheel clutch j is provided on each spindle e of the differential gear to prevent lost motion when either mixer is inoperative. The connection between each driving link u and the corresponding free-wheel clutch d comprises a slotted member s, Fig. 2, pivoted at s<2> to which member the link is connected, and a lever t slotted at s<1> and movable about the axis of the spindle e. The lever t and member s are connected by a roller r disposed within the slots and connected to one end of a bell-crank lever p<2> which, at starting, occupies the position shown, its other end bearing on the diaphragm p<1>. Thus as the diaphragm p' is distended during starting operations, the roller r is moved in the direction of the shaft e so as to change the transmission ratio as the optical system attains normal speed.