. Modern mechanism, exhibiting the latest progress in machines, motors, and the transmission of power, being a supplementary volume to Appletons' cyclopaedia of applied mechanics . uires. The breech-block is worked by a lever arm which travels in a slot, so thatthe first movement of opening gives but a small descent to the block. This motion becomesquicker, until the block falls freely and throws its full weight in aid of the extraction. Theextractors have a straight, positive motion with a long travel, and are actuated by a groovein the breech-block, having a slow motion at first, but exei-ti
. Modern mechanism, exhibiting the latest progress in machines, motors, and the transmission of power, being a supplementary volume to Appletons' cyclopaedia of applied mechanics . uires. The breech-block is worked by a lever arm which travels in a slot, so thatthe first movement of opening gives but a small descent to the block. This motion becomesquicker, until the block falls freely and throws its full weight in aid of the extraction. Theextractors have a straight, positive motion with a long travel, and are actuated by a groovein the breech-block, having a slow motion at first, but exei-ting powerful leverage as theblock is opened wider. The block is supported when open by the head of a stop screwpassing through the side of the breech. The firing mechanism consists of an ordinary pivoted hammer with main and searsprings. Cocking takes place automatically by heel-and-toe cams outside the right part ofthe breech, but it can be done with the fingers, and the entire breech mechanism can beremoved, whether the block be closed or opened. Except the 1-pounder and the mountaingun, all of this system are jacketed to stand a pressure of 18 tons. The projectiles have a. Fig. 5. -Eiigstrom rapid fire gnn. travel of 35 calibers, which makes the gun about 44 calibers long. All guns above 1-poundersmust exceed 2,000 ft. initial velocity, with black or brown powders ; 2,350 ft. being reachedwith smokeless powder. Recognizing the great advantage of the rapid-fire system, and anticipating the large fieldof employment for a reliable and effective weapon of this kind. Lieutenants Driggs andSchroeder, U. S. N., took hold of the subject in 1887, and by careful study and experimentdeveloped a weapon that has already met with favor among naval experts. The jacket is intwo parts, one of which is termed a sleeve and is shrunk upon the tube, the two partsbeing coimected under the trunnion band by the screw thread of the latter. The breechmechanism is in rear of the jacket, which forms its
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Keywords: ., bookcentury1800, bookdecade189, booksubjectmechanicalengineering
