Patent GB-803243-A (GB)
Title: Improvements in or relating to intermittently operated light-exposing apparatus
IPC: G08B5/38
Filed: 1954-02-08
Abstract: 803,243. Visible signalling apparatus. OLDHAM & SON, Ltd., and AKROYD, H. May 6, 1955 [Feb. 8, 1954; June 10, 1954], Nos. 3694/54 and 17150/54. Class 118 (2). An intermittently-operated light-exposing apparatus comprises a lamp in circuit with an electrical power source, a flashing mechanism for producing a predetermined light sequence of set duration on the part of the said lamp, means for varying the light-emitting operation at the end of said sequence, means for completing the said circuit in the upright position of the apparatus and breaking the said circuit in the inverted position of the apparatus, and means for resetting the said flashing mechanism automatically to zero for commencement of the light sequence anew each time the said circuit is completed. The arrangement is described as applied to buoys which are thereby reset automatically by the action of re-stowing after use or after a routine test. In the embodiment of Fig. 1 a clockwork mechanism of usual kind (Figs. 2 and 3, not shown) having an escapement drives a wheel 1 to make and break the contacts of a simple spring set 2 at approximately one-second periods. This intermittently connects the battery B to the lamp and produces a flashing signal. A cam system shown diagrammatically at 4 in its final condition is also driven by the clockwork mechanism through suitable gearing such that the spring set 5 is closed after, say, ten minutes of flashing. The contacts of spring set 5 are in parallel with those of spring set 2 and thus produce a continuous light signal. After a further period of, say, ten minutes the cam system 4 allows the spring set 7 to relax and thereby opens the circuit from battery B to the lamp. A gravity-operated switch 8, e.g. a mercury switch, disconnects the main supply from battery B while the device is inverted. A gravity-operated frictional or spragging means stops the clockwork mechanism when in the inverted position and allows it to run when the buoy is turned into the normal upright position. A glanded lever outside the waterproof casing of the clockwork mechanism is arranged to reset the cams automatically when operated to wind the spring. In the embodiment of Fig. 4 (not shown) two relays in cascade produce impulses at approximately one-second intervals to flash the lamp and drive a " pecker " motor. This motor rotates a cam having contacts which subsequently light the lamp continuously and eventually disconnect the battery supply. A similar gravity-operated switch to that in Fig. 1 is provided to disconnect the supply while the device is inverted. Also on inversion a weight (Fig. 5, not shown) slides against a lever to disengage pawls retaining the cam which is then automatically restored to its start position under the action of a spring. In a third embodiment (Fig. 6, not shown) an impulse motor is driven at constant speed by a vibrator comprising a tuned reed, the frequency of which remains constant (although the amplitude varies) over a wide range of battery voltage. Similar resetting arrangements are employed as in the previous embodiment. In a modification, additional contacts are provided on the vibrating reed and the impulse motor is replaced by a synchronous motor thereby reducing the noise of operation. In a further embodiment (Fig. 8, not shown) a sluggdd " pecker " motor is self-impulsed at a low frequency (e.g. six per second) and drives a train of wheels having one cam with contacts for flashing the lamp, and a second cam with three pairs of contacts for later producing a steady illumination of the lamp, then ultimately switching off the lamp and disconnecting the mechanism from the supply, respectively.