Patent GB-620875-A (GB)
Title: Improvements in or relating to projectile fuzes
IPC: F42C15/24
Filed: 1947-01-28
Abstract: 620,875. Ammunition projectile fuzes. ANSTALT FUR DIE ENTWICKLUNG VON ERFINDUNGEN UND GEWERBLICHEN ANWENDUNGEN ENERGA. Jan. 28, 1947, No. 2684. Convention date, Nov. 2, 1946. [Class 9 (i)] Mechanically delayed arming safety, or firing devices for projectile fuzes comprises two parts having a slide and groove connection, one part being an inertia member which is immobilised in the safety position by means of a spring, the groove being of V-formation and so shaped as to impose a zig-zag path on the part carrying the slide. The arrangement is such that under a sustained thrust the block passes from the safe to an intermediate position, and when the thrust ceases the slide passes to the other branch of the groove, thus bringing the block to the arming position, the movements being slowed down by the zigzag path imposed on the block. In Figs. 1 and 2, showing a percussion fuze, the percussion cap 6 is carried by an inertia block 5 formed with the V-groove 14. This groove is engaged by a slide 13 on a second inertia block 10 acted upon by a weak spring 23, the slide being retained in the blind branch 14b of the groove by the forward thrust of a spring 7. This is the safety position, for even i.f a blow should be accidentally given to the percussion head 2 shearing its retaining wire 21, the striker 3 would not be long enough to reach the cap 6. The block 10 is retained in the position shown by a ball 18. On discharge, the block 5 sets back and the slide 13 enters the end 17 of the groove 14, and when acceleration ceases the slide enters the open-ended branch 14a of the groove, the block 5 moving forwards under the action of the spring 7. Eventually the ball 18 is released, the front ends of the two blocks contact, and both move forwards together to the armed position. In another construction, Fig. 8, the inertia block 5 has similar grooves engaged by slides 13, the block by serving as a limiting stop for the block 10, which carries the cap 6, preventing accidental ignition. On discharge the block 5 sets back against a spring 7 and then moves forwards, as in Fig. 1, to become completely free of the slides, and a spring 30 then moves the cap 6 to the armed position. In another construction, Fig. 13, the striker 3 is in one with the block 5, whose grooves 14 are engaged by slides 13 in the fuze body 1, the striker setting back to the armed position on discharge and being held in this position by the engagement of the slides in the blind branches of the V-grooves. In a further construction the inertia block forms an obstructor, preventing the transmission of the flash to the main charge, the block being moved to the armed position, as above described, on discharge. The Specification as open to inspection under Sect. 91 (4) of the Acts describes also a construction, Fig. 23 (Cancelled), in which the slide 13 is in the fuze body 1 and the groove 14 in the block 5 carrying the striker 3 is so shaped that when the projectile strikes the target the block first moves forwardly under momentum, and then under the action of the spring 7 moves in a zig-zag path rearwardly until freed to enable the striker to strike the cap 6. This subject-matter does not appear in the Specification as accepted.