Patent GB-637152-A (GB)
Title: Improvements in and relating to mechanical time fuzes for projectiles
IPC: F42C9/04
Filed: 1942-07-01
Abstract: 637,152. Projectile fuzes. DELAY, F. July 1, 1942, No. 9101. Convention date, June 25, 1941. [A Specification was laid open to inspection under Sect. 91 of the Acts, Dec. 21, 1942.] [Class 9 (i)] A clockwork fuze for projectiles comprises a clockwork casing which houses a pretensioned driving spring and which is rotated as a whole during the setting operation, inertia responsive means being provided for locking the casing and its setting member on firing, and means responsive to centrifugal force being provided for simultaneously starting the driving and regulating members and promoting the rotation of the release control member of the fuze after linear acceleration has ceased. In the construction shown, the clockwork casing comprises two parts 10, 13, each having mortises for the reception of a stud 13e which prevents relative angular rotation. The casing is mounted for rotation in the fuze body 1 which is fitted with a cap 5 and a clamping ring 6, both of which have parts 5a, 6a engaging in a key 2 of the clockwork mechanism. The lower end of this key is slotted at 2b for engagement with a projection on the casing 1. The lower casing part 10 houses the driving spring 11 which is anchored to the casing and to a bush 41 rigid with a control crown 41c of the detonating mechanism. The bush is also rigidly connected with a toothed crown 39 which meshes with a pinion 38 of the clockwork mechanism. The pinion 38 and other gears of the clockwork mechanism and the balance wheel 30 are all housed within the upper casing part, the balance wheel being under the influence of a torsion leaf spring 28 which, with its adjusting nut, is lodged in a tube 27 arranged within the key 2. Other parts of the apparatus include segments 8 which, by reason of their conical surfaces 8a spread out when they set back on firing, and thus lock the casing 10, 13 and also the cap 5 in the set position. Detonating mechanism.-This mechanism comprises a primer holder 43 slidably mounted within a flanged sleeve 42 and urged upwardly towards a firing pin 14 by a spring 49. Balls 47 in apertures of sleeve 42 prevent such movement, the balls being held in place by a sleeve 48 which is held in the ball-retaining position by a spring 44 and which has a groove for the reception of a locking segment 50 in sleeve 42 when sleeve 48 sets back on firing. From the flange of sleeve 42 projects a pin 46 (see also Fig. 2), which passes freely through an aperture of a release lever 45. When the clockwork casing has been rotated, this lever 45 engages beneath a depending flange of the crown 41c, but, during flight, the crown rotates with the bush 41, and when openings in the crown register with lever 45, the latter and the primer are freed to fly towards the firing pin. Operation.-In the normal inoperative positions, the balance wheel 30 of the clockwork mechanism is held by pins 23a which extend from centrifugally-operated levers 23, the spring 11 is stressed, thereby tending to rotate the crown 41c, and the crown is prevented from rotating by a spring-controlled lever 12 which is pivoted on the casing part 10 and engages a notch 41d in the crown. When setting the fuze by rotating the cap 5, the clockwork mechanism, including the crown, rotate as a whole and the lever 12, by engaging cam surfaces, is moved clear of the notch. On firing, the segments 8 locking the casing as above described, the pins 23a move clear of the balance wheel, and the sleeve 42 sets back, being held in its retracted position by the centrifugallyoperated segments 50. Spring 49 now moves the detonator and lever 45 towards the firing pin, the movement being limited by the lever engaging with the depending flange of the crown 41c. The fuze functions when the clockwork mechanism has rotated sufficiently to bring its notches 41d, 41c into alignment with the lever 45. In a modification, Figs. 7 and 8 (not shown), the lever 45 and associated parts are replaced by a centrifugally-operated arm which is partially unlocked by pins which set back by inertia, and is subsequently held from outward movement by engaging the wall of the crown 41c. When a notch in the crown comes opposite the lever, the latter flies outwards and thus allows the firing pin to move under spring action towards the detonator. In this modification the primer runs forwards by momentum to strike the firing pin should impact occur before the predetermined time of detonation. Specifications 611,606, 621,948 and 637,151 are referred to.