Patent GB-219941-A (GB)
Title: Improvements in or relating to clockwork-operated fuses for shells and the like projectiles
IPC: F42C9/04
Filed: 1924-05-13
Abstract: 219,941. Tavannes Watch Co. Soc. Anon. Jan. 23, 1924, [Convention date]. Projectile fuzes.-A clockwork fuze comprises in combination : an internally-toothed crown member 50, Fig. 4, controlling the release of the striker and connected to a power shaft 42 by means of a reducing gear 46, 47, 49; a ratchet wheel 80 on the power shaft co-operating with a crown pawl 82 having an internally-toothed portion adapted to connect the said shaft to a balance mechanism during the flight of the projectile; a winding and setting key 3 normally connected with the power shaft but adapted to be disconnected therefrom on the departure of the projectile; and a two-part cylindrical casing 20 rigidly connected with the frame of the clockwork movement and with the body of the fuze. The key 3 is connected by pinions 5, 64 to a countershaft 66 connected by pinions 78, 45 to the power shaft 42, and serves to wind the main spring 37 up and simultaneously to set the crown member 50. This member is provided with a notch 55 for releasing a detent 56 at the appointed time. Before the projectile is discharged, the detent 56 is locked at safe and forward rotation of the timing crown member 50 is limited by a bolt 61, Figs. 4 and 19. The crown pawl 82 is loosely held in mesh with the ratchet wheel 80 by springs 85 and is connected by a multiplying gear 88, 92, 93, 94, Fig. 12, to the spindle 95 of the escapement wheel 96. The regulating anchor 97, which is pivoted about the axis of the fuze, has a V-shaped notch 100 engaged by a. screw 101 the adjustment of which determines the amplitude of oscillation of the regulator. The spindle 98 of this anchor carries a balance comprising three arms 104, Fig. 11, with weights 105. The mainspring 37, Fig. 15, is attached at its inner end to a boss 41 secured to the. shaft 42, and at its outer end to a flap 39 pivoted to the drum 27 and adapted to fit into a recess 40 therein when the spring is expanded. When the key 3 is turned before the projectile is discharged, the spring is wound up by the shaft 42, and simultaneously the time ring 50 is set; but the ratchet wheel 82 yields and transmits no rotation. When the projectile is discharged, inertia bolts 61, Fig. 4, and 75, Fig. 10, set back and release the detent 56 and an arm 71 respectively. The arm 71 is swung out about its pivot 72 by centrifugal force; a pin 73 thereon releases the balance 104; and its forked end 70 releases the pinion 64, which is thereupon moved out of mesh with the pinion 5 by a spring 69. The clockwork is thus released, and the ratchet crown wheels 80, 82 transmit the drive from the spring drum to the escapement wheel. At the appointed time the notch 55 in the timing ring 50 comes opposite the detent 56, which under the action of centrifugal force and a spring 59 is swung out of a notch 17 in the spring striker 13, thereby allowing the same to fire a percussion cap 12, Fig. 6. This cap is carried by a thimble 8, which is held back by a spring 9 and locked by a split sleeve 11. When the projectile is discharged, the split sleeve 11 sets back into the thimble 8, so that, if impact occurs before the clockwork releases the spring striker, the thimble 8 by virtue of its momentum drives the percussion cap 12 against the point 16 of the striker. The flash from the percussion cap 12 is transmitted to a detonator 7, which may be preceded by an intermediate detonator 108, Fig. 2. The clockwork mechanism is arranged between plates 22, 23, 24 and washers 28, 29 within the casing 20 made in two longitudinal halves and keyed against rotation within the body 1, Fig. 1, of the fuze. The key 3 is held in the nose-piece 2 of the fuze body by a screw 4, and is geared to a disc 106 which indicates roughly the setting imparted to the clockwork, the exact setting being indicated on the apparatus by which the key 3 is turned. In a modification, the key 3 is secured to the nosepiece 2, which is then rotatably connected to the body of the fuze and has a scale around it for indicating the setting by reference to a pointer on the .fuze body. The anchor escapement and balance wheel shown may be replaced by a deadbeat escapement and a spring balance. The Specification as open to inspection under Sect. 91 (3) (a) also states that the detent 56, instead of releasing the striker directly, may release a sleeve, which in turn releases balls holding the striker. This subject-matter does not appear in the Specification as accepted.