GB994761A - Improvements in or relating to safety devices for projectile fuzes - Google Patents

Abstract

994,761. Projectile fuzes. DIRECTOR GENERAL OF FORSVARETS FABRIKSSTYRELSE. Oct. 9, 1963, No. 39858/63. Heading F3A. A projectile fuze, particularly intended for mortar shells, is provided with a safety device which comprises a piston 3 and a plate 9, which components adhere to one another due to the surface tension effect of a layer of oil or grease 13 between machined parallel faces of these components, and a spring 7 adapted to urge the piston 3 and plate 9 apart and which causes separation after a time delay caused by the layer. In the embodiment shown a cylinder 1 carries a detonator 2 and is urged to rotate about a pin 10 by a spring 6. On launching the projectile, a member (not shown) sets back to release the cylinder 1, but the cylinder is prevented from rotating by set back of piston 3 and the entry of a firing pin 4 within a cavity 8, the piston being retained rearwardly by the grease layer 13. The plate 9 is loosely fitted on pin 10 and is held peripherally by a spring 11, which arrangement allows it sufficient play to ensure parallelism with the piston 3. On separation of plate 9 and piston 3 by spring 7, cylinder 1 is freed to rotate thereby bringing detonator 2 in line with firing pin 4 and a second detonator 5. On impact, the piston 3 is driven rearwardly by direct action of an extension screwed into the piston at 15 prior to launching. The fuze is provided with a detachable humidity-proof cover 14. In a second embodiment the piston and plate are both longitudinally movable within the fuze and are initially held together by a layer 13. On set back of the piston, the plate is rearwardly retained by projections on the pin 10 and spring-urged separation of the components takes place as before after a time interval.