AnAsbury Mechanism opens and closes thebreech of heavy artillery for reloading with a projectile and bags ofpropellant. It was widely used fornaval artillery of theworld wars and similarcoastal artillery andrailway guns. The device was invented at theWashington Navy Yard in 1916 by draftsman Dorsey Frost Asbury. It is sometimes called a Smith-Asbury mechanism by theUnited States Navy in recognition of Asbury's supervisor, Lieutenant Commander George Leonard Smith, USN.[1]
Large caliber breech-loading artillery became practical with French development of theobturator byCharles Ragon de Bange in 1872; and speed of reloading was improved by adaptation of theinterrupted screw breech plug, which was later further improved byAxel Welin in 1890 as theWelin screw breech and adopted by the Swedish.[2] Asbury used gearing to fully open a Welin breech by linking the unscrewing, withdrawing and swinging clear movements into one continuous action.[1]