Patent GB-361319-A (GB)
Title: Improvements in or relating to fuses for projectiles
IPC: F42C9/06
Filed: 1930-08-13
Abstract: 361,319. Projectile fuzes. SPERRY GYROSCOPE CO., Inc., Manhattan Bridge Plaza, Brooklyn, New York, U.S.A.-(Assignees of Doe, T. B. ; 2, East 86th Street, New York, U.S.A.) Aug. 13, 1930, No. 24245. Convention date, June 6. [Class 9 (i).] A fuze for projectiles comprises a firing pin or hammer normally held retracted by a detent which coacts with a member which is initially restrained from movement by the air pressure due to the flight of the projectile, yielding means opposing the air pressure being provided for withdrawing the detent when the pressure falls to a predetermined value. The said member is arranged within the body of the fuze. According to one construction, a hammer 1, Figs. 6 and 8, is slidably mounted in a transverse groove 2 and is adapted, when released, to strike one of the detonator caps 4, 4<1>, which communicate with the main charge of the projectile through powder trains 5, a space 6, and channels 7. The hammer is thrown outwards, when released, to strike one of the detonator caps by the centrifugal force due to the rotation of the projectile, an inclined passage 10, Fig. 3, being provided to facilitate its movement in the groove 2. The hammer is normally held retracted by a detent 8 having a stem 81 to which is secured a piston 32 and a plate 11. The lower surfaces of the plate 11 are engaged by the bases 14 of two L-shaped members 12, 13, the upright limbs of which are forked and embrace the plate. These members normally rest on plates 16 slidably mounted on slotted members 18 and connected by pins to nuts 19 on screws 20, 20<1>. The outer ends of the screws have pinions 28, 29 which mesh with teeth 27 of a rotatable ring 26. By this means, the radial positions of the nuts 19, and hence the members 12, 13 can be adjusted. In operation, the members 12, 13, by centrifugal force, tend to tilt and raise the plate 11 and thus release the detent 8. This action is prevented for a time by the air pressure acting on the piston 32 via the passages 33, 34. At a predetermined time in the projectile's flight, regulated by the ring 26, the lifting force exerted by the members 12, 13 overcomes the diminishing air pressure, and the detent is raised. Premature release in the gun barrel is prevented by a ball 40 which, by its inertia during acceleration, is forced against the piston but which is thrown out of engagement therewith by centrifugal force after the projectile leaves the gun. A further safety device is in the form of two hinged leaf springs 30 which normally engage grooves 31 in the member 11 and which are also released during the flight of the projectile by centrifugal force. In a modification, the screws 20, 20<1> are at right-angles to the longitudinal axis of the projectile and the springs 30 are arranged in a longitudinal direction. In a further modification, Fig. 10, the stem 77 of the detent 76 is screw-threaded in a nut 81 and has a flared portion 78 forming the nose of the fuze. The nut 81 is rotatable in one direction only and is held in position by a screw-threaded ring 80. In operation, the stem is rotated to release the detent 76 by a coiled spring 84 when the force exerted thereby is sufficient to overcome the opposing frictional force exerted by the air pressure on the nose. Premature release is prevented by a second detent 70 on a plunger 71 which is thrown rearwards on discharge and held in its rearward position by a split ring 73. A further safety-device consists in spring-pressed plungers 86 which bear against a ring 88 on the stem during the accelerating movement and which are subsequently released by centrifugal force.