GB568656A - Improvements in or relating to indicating means for use in observing the flight of projectiles - Google Patents

Abstract

568,656. Time-alarm signals. REYROLLE & CO., Ltd., A., and STEVENSON, W. M. June 16, 1939, No. 17705. [Class 118 (ii)] Relates to apparatus for giving an indication, after a predetermined time from the release of a projectile or torpedo, that the projectile is about to reach a target. According to the invention, apparatus of this kind comprises electric contacts operated by the release of the projectile, two or more timing devices, each set in motion by the operation of the contacts to give an indication after a predetermined timeinterval, and a change-over relay also controlled by the contacts and serving to connect the contacts to the, different timing devices in succession. The apparatus comprises a source of electricity such as a battery A, Fig. 1, a number of pairs of contacts B, each situated on or near one gun and momentarily closed by the recoil or blast, a number of timing devices C, and a selector relay K for bringing the timing devices into operation successively. Each timing device is provided with instantaneous contacts D for closing the circuit of one or more lamps E to indicate when a projectile is in flight, and delayed contacts F for closing the circuit of one or more lamps G and buzzers H after a prodetermined time-interval. The relay comprises a selector switch rotated step-by-step by a ratchet-and-pawl which is operated by a solenoid and a spring, a mechanical time-lag device being used to delay the movement of the switch from one contact to the next until a predetermined time after the relay has been released. The timing device consists of a solenoid C, Fig. 3, which when energized pulls down an armature C<1> until further movement is prevented by an adjustable stop M. The initial part of the movement allows a pair of instantaneous contacts D to close and, almost simultaneously, opens a pair of delayed contacts F, the whole of the movement being substantially instantaneous. The armature C<1> is connected through a freewheel clutch with an eddy current disc C<2> provided with a permanent magnet brake C<3>, so that the return movement of the armature under the action of a weight N or a spring R takes place relatively slowly. Thus when the solenoid C is de-energized, the armature C<1> moves slowly upwards, and after a period deter. mined by the position of the stop M it closes the delayed contacts and, after a further fixed period, opens the contacts D to extinguish the lamps E, G. The adjustment of the stop M, for determining the interval of all the timing devices, is carried out by means of an adjusting member, such as a knob, associated with a scale graduated with the range of the gun. In addition, a scale is provided to enable the device to be set so that an " observe " signal is given at any desired time before the projectile reaches the target.