GB549998A - Electrical systems or circuit arrangements for producing an electrical impulse with variable time delay - Google Patents

Abstract

549,998. Projectile fuzes and apparatus for setting the same. CLAESSON, M. A. June 20, 1941. No. 7800. Convention date, June 21, 1940. [Class 9 (i)] [Also in Group XL] In a gaseous discharge tube system arranged to produce an electrical impulse with variable time delay adapted to operate a fuze for igniting a priming composition in a projectile or the like a timing condenser is provided and so arranged that the time increases with increase of the voltage to which the condenser is charged. A current of limited value may be passed through the tube immediately before operation to increase the constancy of the starting potential as described in Specification 548,405. Fig. 6 shows an arrangement in which an ignition condenser. C' is charged to a voltage U higher than the starter potential Vt of the tube G while the timing condenser C2 is charged to an opposing voltage V and the time interval is determined by its discharge through resistance R until the tube ignites and operates fuze F. When voltage U = Vt x a where a is a constant the timing interval is independent of the voltage Vt. A safety switch S operated by the acceleration of the projectile may be provided. Fig. 7 shows an arrangement for applying the required voltages to condensers C<SP>1</SP>, C2. A voltage equal to the starting potential of the tube G is obtained across the points 4, 5 since condenser C' is charged over resistance L until the tube G ignites when relay P is operated over an amplifier H to break the charging and discharging circuits at contacts p<SP>1</SP>, p<SP>2</SP>, respectively, which voltage with the addition of constant voltage M is used to charge the condenser C<SP>1</SP>. Condenser C<SP>2</SP> is charged to the voltage required to produce the desired time either by manual adjustment or the timing voltage is automatically derived from the firing control device adjusted in accordance with the ballistic parameters. The voltage source M may be variable to control the sensitivity at various ranges and the condenser C<SP>3</SP> may be discharged by a protective resistance. As applied to the firing of shells, these may be fed so as successively to pass current through the tube, to charge the ignition condenser and in a third position to charge the timing condenser, the last position being the firing position. Specification 408.706, [Croup XXXVIII], also is referred to.