Patent GB-1199707-A (GB)
Title: Improvements in or relating to a Time Fuse for Projectiles
IPC: F42C9/02
Filed: 1969-02-24
Abstract: 1,199,707. Projectile fuzes. MEFINA S.A. 24 Feb., 1969 [4 April, 1968], No. 9753/69. Heading F3A. A time fuze for a spinning or non-spinning projectile providing transport, bore and trajectory safety comprises a movable carrier 41, Fig. 8, for bringing a primer 45 into line with a spring loaded striker 38, clockwork and escapement mechanism 2, Fig. 1, for controlling the operation of the striker and for preventing movement of the primer for a predetermined time after the projectile has been fired, a rotatable cap 6 movable with respect to the fuze body 1, a disc 3 turned by the cap, a clockwork drive spring 27, Fig. 8, a clockwork drive spindle 19 rigid with the disc 3 so as to tension the spring 27 when the cap 6 is rotated and thereafter to be subject to the torque of the spring, a retractable coupler 10, Fig. 1, for connecting the cap and disc, the coupler actively connecting the cap and disc when the fuze is not set and being movable to an inactive position when the spring 27 has been tensioned and the projectile axially accelerated. The coupler is held in its active position in a notch in the periphery of the disc 3 by a stop 5 on the body of the fuze. Weights 13 mounted on a leaf spring 12 are provided for moving the coupler into its inactive position. The clockwork and escapement mechanism comprises a cam 20, Fig. 8, rigid with the drive spindle 19, a main wheel 26 rotatably secured on the spindle by an elastic washer 25, intermediate wheels 29, 30 and an escapement mechanism 31, 32. The surface 70 of the spring loaded striker tends to drive a blocking plate 40 out of engagement with the striker, but movement of the plate is prevented by a shaft 33, Fig. 3. A bolt 36 carried by the shaft 33 is urged by a spring 35 against the periphery of the disc. The primer carrier is held in a safe position by a pin 68 and is further prevented from moving to the armed position by a finger 37 fixed to the shaft 33. A collar 48 on the pin 68 engages the balance 32 of the escapement mechanism and prevents operation of the clockwork. The pin is surrounded by inertia bushes 46 and 47 and resilient fingers 63 of the bush 46 engage in one of two grooves 61, 62 whilst the bush 46 is locked by cam 20. When the cap 6 is rotated, the motion is transmitted through the coupler 10 to the disc 3 and spindle 19 to tension the clockwork drive spring 27. Since the balance 32 of the escapement is locked by the collar on pin 68, the main wheel 26 remains stationary during rotation of the shaft 19. Rotation of the cap also moves the coupler out of engagement with the stop 5, and, rotation of the disc 3 disengages the cam 20 from bush 46. Upon firing the projectile, the weights 13 set back to lift the coupler out of the notch in the disc. Meanwhile the bushes 46, 47 set back and the fingers 63 engage in groove 62. As the projectile leaves the muzzle of the weapon from which it is fired, pin 68, Fig. 3, is lifted by spring 50, whereupon the carrier 41 is released for rotation under spring action and the balance 32 is released to permit operation of the clockwork. Rotation of the carrier to the armed position is prevented by finger 37 until the clockwork has rotated the disc 3 to a position in which the bolt 36 can enter the notch in the disc and permit rotation of the shaft 33 and thereby the finger 37. Further rotation of the disc permits deeper penetration of the bolt into the notch and further rotation of the shaft 33, whereupon a recess 34 in the shaft is aligned with the striker blocking plate 40 which then rotates to permit the striker to be driven against the primer.