. American telephone practice . FIG. ELEVATION AMERICAN DROP AND TACK. tion, the path through which it swings being indicated by thecurved dotted line. Repairs on these drops may be readily made,as the entire structure of any drop and jack may be withdrawn fromthe front face of the board by removing the thumb-nuts. 1 and 2, Great sensitiveness can never be attained with this drop, becausethe shutter rests upon the armature rod in such manner as to bear 200 AM ERIC AX TELEPHOXE PRACTICE. upon it with its entire weight. It can therefore only be releasedby a considerable effort on the p
. American telephone practice . FIG. ELEVATION AMERICAN DROP AND TACK. tion, the path through which it swings being indicated by thecurved dotted line. Repairs on these drops may be readily made,as the entire structure of any drop and jack may be withdrawn fromthe front face of the board by removing the thumb-nuts. 1 and 2, Great sensitiveness can never be attained with this drop, becausethe shutter rests upon the armature rod in such manner as to bear 200 AM ERIC AX TELEPHOXE PRACTICE. upon it with its entire weight. It can therefore only be releasedby a considerable effort on the part of the armature, this effort beingdue to the friction between the shutter and the armature rod. Another form of mechanically self-restoring drop is that now \Mc inmmmwmmmmmmn I H«»mimrtmi»ttmiw«. FIG. 1S4.—TOP VIEW, WTTH COIL REMOVED. manufactured by the American Electric Telephone Company. Inthis drop, which is shown in Figs. 183, 184 and 185, the actuatingcoil is mounted directly above the spring-jack. The coil is inclosedon the sides in a sheet-iron frame or box, C, for lessening the amountof induction between adjacent drops. The armature of the magnetis pivoted at the rear of this shield, and carries a forwardly project-
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Keywords: ., boo, bookcentury1900, bookdecade1900, bookidamericantelepho00mill
