The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . in the last-named service,owing to the defect already named, all the latest guns, both lightand heavy, use metal cartridge cases. In the French navy, as in 2o6 ORDNANCE (HISTORY AND CONSTRUCTION most other services, cartridge cases are used for the smaller andmedium guns only. One of the most efficient obturators not liable to damage is theplastic device introduced by Colonel de Bange of the Frenchservice and adopted by the French army and also by the Britishand other governments. It consists of a
The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . in the last-named service,owing to the defect already named, all the latest guns, both lightand heavy, use metal cartridge cases. In the French navy, as in 2o6 ORDNANCE (HISTORY AND CONSTRUCTION most other services, cartridge cases are used for the smaller andmedium guns only. One of the most efficient obturators not liable to damage is theplastic device introduced by Colonel de Bange of the Frenchservice and adopted by the French army and also by the Britishand other governments. It consists of a pad (fig. 52) made up ofa strong annular-shaped canvas bag A, containing a mixture ofasbestos fibre and mutton suet; the bag with its contents is placedin a properly formed die and subjected to hydraulic pressure bywhich it becomes hard and firm. The pad so made is then placed onthe front of the breech screw B, and it is protected on its faces bydisks C, C, of metallic tin or copper having steel wedge rings onthe outer edges; the circumference of the complete pad and disks is H1N66 Pin ORREI. BBEECH SCBfw ^ lockW Fig. 44.—English modern Breech Mechanism, for heavy and medium guns, generally only slightly coned and fits into a corresponding seatingformed at the breech end of the chamber, the canvas of the circum-ference of the pad being in immediate contact with the seat. Inthe English service the steep cone pattern (fig. 53) of de Bangeobturator is used with mechanisms having the VVelin screw. Infront of the pad is placed a strong steel disk formed with a spindle,and called a mushroom head D, the spindle passing through thehole in the pad and through the breech screw, being secured inrear by a nut. The firing vent is generally drilled through themushroom head and spindle and the part is then termed a ventaxial. On the gun being fired the gas exerts a great pressure onthe mushroom head, which compresses the pad and squeezes itout on the circumference into close contact with
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Keywords: ., bookcentury1900, bookdecade1910, bookidencyclopdiab, bookyear1910
