Patent GB-1273208-A (GB)
Title: Improvement in or relating to ballistic devices and projectiles
Inventor: CELS ANDRE
IPC: F42B5/16
Filed: 1969-07-29
Abstract: 1,273,208. Ballistic assemblies; mortars. ARAMA S.A. 29 July, 1969, No. 37893/69. Headings F3A and F3C. A ballistic assembly consisting of a projectile, e.g., an arrow, rocket, grenade or bomb, and its launching device comprises, one or more tubular casings in which a propellant charge is confined within one or more chambers, the casing or casings being hermetically sealed by a piston so that the propellant charge produces two pressure peaks which are off-set in time and exceed a pressure corresponding to the elastic limit of the casing or casings but, because of their short duration, do not cause permanent deformation of the casing or casings. In one embodiment, Fig. 27, the tubular casing 140 contains a piston 141 and a thrust rod 143 which is integral with the finned tail unit 144 of a grenade. Upon firing the propellant charge, the tail unit moves relative to the head 145 of the grenade and its inertia resistance determines the first pressure peak. The second peak occurs as the head is brought into movement by a damping fluid in a space 146 and the action of the push rod on the end wall of the space 146. From this moment the head and tail unit are secured together by a spring pin (not shown). If the resistance force of the projectile is insufficient to bring about the second pressure peak its resistance can be amplified with an hydraulic piston. In another embodiment, Fig. 25, the piston 126 is supported on a fixed launching device 124. A sleeve 128 slidable within the tubular casing 129 forms part of a projectile and contains the propellant charge in two chambers 130 and 131. The charge in chamber 131 is ignited with delay by the preceding charge to produce the second pressure peak. The sleeve 128 is ejected from the launched projectile by residual gas pressure acting on a partition 132. In a modification (Fig. 26, not shown) a piston (136), through the agency of a sleeve (139), acts on the projectile (138) under the action of the pressure peak of a first charge, a second charge being ignited by hot gases passing through bores in the piston. In another embodiment, Fig. 6, a thrust rod 32 for the projectile contacts a piston formed with a striker 30a. The striker ignites a propellant 31 when a sleeve 28 is driven forwards by a piston 24 under the action of the gases from a first charge 25. In another embodiment, Fig. 9, two charges 45 and 51 for producing first and second pressure peaks are separated by a piston 44. The hot gases from the charge 45 pass through bores 54 and 56 and an expansion chamber 57 containing a filter to ignite the charge 51 after a short delay. In other modifications delay in igniting a second charge by a first charge is effected by extrusion of clay (58, Fig. 10, not shown) through a bore in a separating piston, or the bursting of a diaphragm (74, Fig. 11, not shown), or with a delay charge and fusecord (60, 60a, Fig. 12, not shown). In another embodiment (Fig. 13, not shown) a charge (91) is ignited by hot air compressed by a piston (84) driven by a first charge. In a number of other embodiments, (Figs. 14-24, not shown), the two pressure peaks are produced by charges having different burning rates, the charges being admixed or retained in separate zones in the form of rods, tandem or concentric charges. The charges can be ignited by one another through delay means of the kind previously described, or through a delay partition constituted by a fusible metal or capsule of liquid, or by a charge (122, Fig. 24, not shown) which is compressed by the piston. The off-setting of the time of firing of any of the propellant charges can also be brought about by piezo-electric means or by bringing into action at the desired moment one or more electric, piezo-electric, or percussive devices.