Abstract: A ballistic projectile (10) includes a body (12) defining a hollow, open-ended payload cavity (22) covered by means of a cover portion (26) fitting as a spigot into a socket (12.1) defined by the body (12). Peripheral seats in the form of grooves (32), (34) are provided in register in peripheral slide surfaces of respectively the cover portion (26) and the body (12) forming the spigot-socket combination. A peripheral, discontinuous shear ring (36) is received within the respective grooves (32), (34) to bridge the interface and thus to lock the cover portion to the body. Pressure selectively generated in the payload cavity shears the ring (36) to allow parting of the cover portion to expose the payload cavity.

Abstract: A ballistic projectile (10) includes a body (12) defining a hollow, open-ended payload cavity (22) covered by means of a cover portion (26) fitting as a spigot into a socket (12.1) defined by the body (12). Peripheral seats in the form of grooves (32), (34) are provided in register in peripheral slide surfaces of respectively the cover portion (26) and the body (12) forming the spigot-socket combination. A peripheral, discontinuous shear ring (36) is received within the respective grooves (32), (34) to bridge the interface and thus to lock the cover portion to the body. Pressure selectively generated in the payload cavity shears the ring (36) to allow parting of the cover portion to expose the payload cavity.

Abstract: A cartridge assembly 10 includes a shell 12 containing a propellant charge 19. At a rear, open end, the shell 12 holds a force amplifying initiating device 20, in turn holding a rim fire primer 22 in operative association with the propellant 19. A firing pin body 40 is movably held within the device 40 to expose a rear of the body 40 to a shock wave to initiate the device 20. A fore end of the body 40 includes a taper formation 48 having a rounded fore point 50 aligned with an inactive surface of the primer 22 centrally within a firing rim. Inadvertent (mechanical) actuation of the firing pin 40 will fall to cause sufficient and sufficiently fast impingement on the primer to initiate the primer. Only a shock wave can cause initiation. The primer 22 is held in a collar 34 allowing it to flare open upon initiation and holding it within the shell 12 after initiation.

Abstract: A cartridge assembly 10 includes a shell 12 containing a propellant charge 19. At a rear, open end, the shell 12 holds a force amplifying initiating device 20, in turn holding a rim fire primer 22 in operative association with the propellant 19. A firing pin body 40 is movably held within the device 40 to expose a rear of the body 40 to a shock wave to initiate the devise 20. A fore end of the body 40 includes a taper formation 48 having a rounded fore point 50 aligned with an inactive surface of the primer 22 centrally within a firing rim. Inadvertent (mechanical) actuation of the firing pin 40 will fail to cause sufficient and sufficiently fast impingement on the primer to initiate the primer. Only a shock wave can cause initiation. The primer 22 is held in a collar 34 allowing it to flare open upon initiation and holding it within the shell 12 after initiation.

Abstract: A method of breaking rock (18), e.g. in underground mining, includes drilling a hole in the rock mass by means of a drilling machine (20) having an articulated boom (22) and a drilling tool (24) at the end of the boom (22). After drilling, the drilling tool (20) is retracted, charge means is indexed with the hole, and a rock breaking charge (30) is charged into the hole. The charge (30) includes a propellant, a fuse head (40), and a tamping medium (34), conveniently contained in the casing (32). The tamping medium (34), e.g. a two-component resin, is discharged into the hole and allowed to set around and rearward of the propellant. The driving machine (20) is removed and the propellant is actuated from a remote position, e.g. electrically.

Abstract: According to the invention there is a provided an obturation assembly for a gun of the type comprising a barrel of which a rear end defines a firing chamber having an obturation seat and the gun further having a breechblock, the obturation assembly comprising: an obturation set including an annular obturator pad for sealing against the obturation seat; an obturation spindle having a shaft and a head, the shaft extending coaxially through the obturator pad; a first shim for location between the obturation set and the breechblock, and a second shim for location between the obturation set and the head of the obturation spindle.

Abstract: A thruster for a helicopter is mounted in a rear portion of a tail boom. Two sets of vanes deflect an airflow stream flowing along the tail boom respectively to opposed sides of the tail boom. Two shutters are pivotally arranged partly around the sets of vanes to leave two openings in respective sides of the tailboom. The shutters are pivoted in sympathy toward each other or away from each other to open/close the respective openings symmetrically and simultaneously such that a geometrical center line of each opening remains static irrespective of the status of the opening.

Abstract: An impulse generating tool for breaking up rock has a barrel, a breech body for a cartridge (50) loaded with gas producing propellant (70) and a firing mechanism for firing the cartridge. A hole is drilled in the rock and filled with water. The barrel is passed down the hole and the cartridge is fired. Shockwaves break up the rock. A firing pin (42) of the firing mechanism is off-set (56) from a centerline (54) of the breech body, and the cartridge, which is of a shotgun type, has a rim-fire percussion cap (63) complemental to the off-set of the firing pin. Conventional shotgun ammunition cannot be fired with the tool, and cartridges for the tool cannot be fired by a conventional shotgun.

Abstract: An impulse generating tool for breaking up rock has a barrel, a breech body for a cartridge (50) loaded with gas producing propellant (70) and a firing mechanism for firing the cartridge. A hole is drilled in the rock and filled with water. The barrel is passed down the hole and the cartridge is fired. Shockwaves break up the rock. A firing pin (42) of the firing mechanism is off-set (56) from a centreline (54) of the breech body, and the cartridge, which is of a shotgun type, has a rim-fire percussion cap (63) complemental to the off-set of the firing pin. Conventional shotgun ammunition cannot be fired with the tool, and cartridges for the tool cannot be fired by a conventional shotgun.

Abstract: A modular concept for a gun which uses a breech conversion kit allows the firing of cased and caseless ammunition with the same gun. The cannon has 2 breech mechanism (10) which includes a first sliding breech-block (19) which engages the rear end (15) of a cartridge case in the firing position. Said first sliding breech-block (19) is interchanged for a second sliding breech-block (21) when firing caseless ammunition. Said second breech-block is in contact with a scaling member (23) which is mounted pivotally on an axis (27) which is located on the upper face of breech ring (11).

Abstract: In a helicopter having a main rotor, a tail boom and a circulation control slot along one side of the tail boom, and a thruster which is selectively directable at either side or both sides of the rear end of the tail boom, anti-torque and yaw control are effected by generating separate air flow streams of different pressures by means of separate pressure means and conducting said separate air flow streams at said different pressures in separate passages to respectively the circulation control slot and to the thruster.

Abstract: An ammunition feeder chute includes a plurality of unitary segments injection molded from a flexible thermoplastics material. The segments are articulated to one another in side-by-side relationship, and are interconnected by a cable which passes through a pair of apertures formed in opposed side walls of each segment. The opposed side walls are joined by an elongate base member which has a predetermined torsional flexure for facilitating overall torsional flexure of the feeder chute. Each segment is formed with complemental arcuate tab and recess formations for allowing pivoting of adjacent segments relative to one another.