| 摘要 |
An arming-delay mechanism suitable for use in artillery shells to prevent premature arming and explosion of the shell, employing an escapement including a balance which is "unbalanced" in that its pivot axis is radially further outward than its center of gravity with respect to the spin axis about which the mechanism spins after the shell is fired. It also includes two sequentially operating centrifugal detents for preventing accidental starting of the operation of the timing mechanism prior to firing of the shell, with the balance arranged to serve as an interlock between the two detents whereby the second detent cannot be actuated to its open position until after the first detent has been actuated. Arming is produced, after spinning of the shell releases both detents in sequence, by means of a centrifugally operated rotor having escapement teeth on it, which teeth engage the balance directly rather than through a gear train. The unbalanced balance responds to centrifugal forces produced during spinning to resist motion of the rotor more strongly than a "balanced" balance of the same mass, making possible a smaller, lighter and simpler mechanism for a given amount of delay, and the sequentially operating arrangement of detents provides a high degree of safety from premature accidental arming.
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