In order to stop the clock, then, it is only necessary to pull on this
cord slightly, when, by moving the pendulum to the left, it will thrust
it against the inclined plane of the finger of the lever arm, A. It is
clear that the extremity of the pendulum, upon striking against the
finger, will depress it slightly and go beyond the projection against
which it remains fixed owing to the counterpoise, _i_. The fever, _n n'_,
is brought back to its position of rest by means of a small counterpoise
at the extremity of the arm, _n_. When the lever, A, is depressed, the
pendulum escapes and sets the clock running. This depression is effected
by means of an electro-magnet, E, whose armature, which is connected with
the rod, _t, t_, lifts the arm, _i_, of the lever, and depresses A. The
wires of the two bobbins of the electro-magnet end in two clamps, 1 and 2.
The second of these latter is insulated from the clock-case. Both
communicate with the extremities of the circuit in which is interposed the
seismic telltale that brings about a closing of the current. Having noted
the position of the hands on the dial when the clock was running, one can
deduce therefrom the moment at which the shock occurred that set the clock
in motion.
In addition to the parts that we have described, there are other accessory
ones, R R_r_, and a third clamp, 3, which constitute a sort of rheotome
that is designed to keep the circuit closed after the momentary closing
that is produced by the telltale has occurred.
Pages:
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72