Читать книгу The Modern Clock. A Study of Time Keeping Mechanism; Its Construction, Regulation and Repair онлайн

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As with the hairspring, it is quite necessary that the pendulum spring be accurately adjusted to isochronism and my advice to every jeweler is to thoroughly test his regulator, which can easily be done by changing the weight or motive power. If the test should prove the lack of isochronism he can adjust it by following these simple rules. ssss1 is the pendulum spring or leaf. If the short arcs should prove the slowest, make the spring a trifle thinner at B; if fastest, reduce the thickness of the spring at A. Continue the test until the long and short arcs are equal. In doing this care must be taken to thin each spring equally, if it is a double spring, and each edge equally, if a single spring, as if one side be left thicker than the other the pendulum will wabble.

Fig. 16.

The cause of a pendulum wobbling is that there must be something wrong with the suspension spring, or the bridge that holds the spring. If the suspension spring is bent or kinked, the pendulum will wabble; or if the spring should be of an unequal thickness it will have the same effect on the pendulum; but the main cause of the pendulum wobbling in American clocks is that the slot in the bridge that holds the spring, or the slot in the slide that works up and down on the spring (which is used to regulate the clock) is not parallel. When this slot is not parallel it pinches the spring, front or back, and allows it to vibrate more where it is the freest, causing the pendulum to wabble. We have found that by making these slots parallel the wobbling of the pendulum has ceased in most all cases. If the pallet staff is not at right angles to the crutch, wobbling may be caused by the oblique action of the crutch. This often happens when the movement is not set square in the case.