GB647366A - Improvements in or relating to fin assemblies for projectiles and the like - Google Patents

Abstract

647,366. Ammunition projectiles. BRISTOL AEROPLANE CO., Ltd. May 10, 1948, No. 12843. [Classes 9 (i) and 9 (ii)] A fin assembly for a projectile is provided wherein the fins are pivotally mounted on a frame and each is independently held in the folded position by a catch, all the catches being simultaneously unfastened from the frame and connected with a common release gear, when the assembly is fitted on the projectile. A sea-mine 10 adapted to be dropped from aircraft comprises a mine body 11 and a detachable fin system 12. The fin system' comprises four fins 13 hinged at 14 to a frame 15, Fig. 2, the fins swinging outwards when the mine is dropped and the fin' system being automatically thrown off when the mine hits the sea. The frame 15 comprises a cylindrical member 16 with axially spaced flanges 17, Figs. 2 and 3. The pivoted fins, mounted on tubes 18 extending between the corners of the flanges, Fig. 3, are held in the folded position, Fig. 4, by two-headed pins 19. Each fin has an upstanding flange 22 with a slot 23 receiving one end of a pin 19, the opposite end resting in a slot 24 in the member 16. Each pin is connected by a rod 25 to a bracket 27 and held there by a hook 28. Normally the bracket lies within the member 16, but when the frame is placed on the mine, the bracket is pushed out so that the rods 25 are disengaged from the member 16. On launching, a cable removes the hook 28 whereupon the fins fly outwardly under the action of springs 36.' Each fin carries an arm 29 pivotally connected to a link 30, the free end 39 of which moves on a slide 33 secured to the member 16, and comes to rest in slot 34 when the fins are extended (dotted lines in Fig. 4). The spring 36 is anchored to the link 30 and to a bracket on the member 16. A device 50 is provided for releasing the frame 15 when the mine strikes the water. This device consists of a bracket 40 on the member 16 connected to a flange 17 by a rod 41, Fig. 3. The bracket also carries a lever 42, one arm 43 of which, acted on by a spring 45, passes through an opening in the member 16 to engage the mine 11. The other arm 46 of the lever lies behind a weight 47 slidable on the rod 41. A locking wire 48 holds the weight clear of the arm 46. On impact the weight 47 shears the wire 48 and strikes the arm 46 so that the arm 43 is released and the mine is freed from the frame. Two devices 50 are placed at diagonally opposite corners, Fig. 2.