GB572791A - Improvements in or relating to delaying mechanisms for use on projectiles - Google Patents

Abstract

572,791. Projectile fuzes. WEST & CO., Ltd., A., and BREEZE, V. L. Dec. 18, 1941, No. 16357. [Class 9 (i)] Fuzes for projectiles which accelerate for a considerable period, e.g. self-propelled rockettype projectiles, comprise means for delaying arming of the fuze until the acceleration has fallen to a given value. In the construction shown, the arming of the fuze is accomplished with two pairs of fixed contacts 9 which are bridged by two contacts 10. Prior to discharge of the projectile, the parts are in the position shown. Each contact 10 is mounted on a lever 11 which is pivoted at 11a and pulled clockwise by a spring 5 anchored to the vertical arm of a bell-crank lever 3. The horizontal arm of the lever 3 abuts the lever 11 and holds the contact 10 away from the contacts 9. The lever 3 is and fixed on the shaft, between the plates, is a mass 6. It is to be assumed in the drawings that the projectile travels upwardly. When the projectile is discharged and accelerates, the mass 6 moves downwards by inertia and thus rotates the shaft 7 and disc 8 anti-clockwise. When the disc 8 has moved through 90 degrees, an opening 12 in the disc is opposite the tail 3a, so that the tail may drop into the opening and the lever 3 may rock clockwise to allow the contact 9, 10 to be made ; but the tail does not immediately drop into the opening, for the horizontal arm of the lever 3 also is held back by inertia. When the acceleration drops to a certain value, the spring 5 rocks the lever 3 clockwise and the contact 9, 10 is made. A safety device which ensures that the mass 6 will not move downwardly when the device is dropped, comprises a fly-wheel 13 so geared to the shaft 7 that as the shaft rotates slowly the fly-wheel moves rapidly. This device may be replaced by an air dashpot. The mass 6 is biassed to the normal position by a light spring 14. When the mass 6 reaches its permissive (opening-opposite-tail) position, it is latched there by a spring 15 which engages a recess 16 in the mass. The members 3 also may be latched-in after they have moved clockwise. In modified arrangements, (a) a circuit normally established may be interrupted by movement of the tail away from the disc 8 ; (b) the radius of that part of the surface of the disc 8 extending between the tail 3a and the opening 12 may increase, thus providing a delay additional to that caused by the fly-wheel 13. The elements 3, 8, 9, 10, 11 are duplicated on each side of the mass 11. The device is mounted on a base 1.