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

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The width of this compound spring for a seconds’ pendulum of average weight may be .60 inch, from outside to outside, each spring .15 inch wide. This will separate the springs .30 inch in the center. With this form of spring, the lower end of each spring being held in a pair of clamps, the clamps will have to be let into the top of the rod, and held in by a stout pin, or the pendulum finished with a hook which will fit the clamp. In letting the clamp into the rod, the clamp should just go into the mortise and be without side shake, but tilt each way from the center a little on the pin, so that when the pendulum is hung it may hang perpendicular, directly in the center of both springs. Also, the top pair of clamps should fit into a bracket without shake, and tilt a little on a pin, the same as the lower clamps. These two points, each moving a little, helps to take any side twist away, and allows the whole mechanism to swing in line with the center of gravity of the mass from end to end. With the parts well made, as described, the bob will swing in a straight line from side to side, and its path will be without any other motion except the one of slight curvature, due to being suspended by a fixed point at the upper clamp.