Patent GB-190905687-A (GB)
Title: Improvements in Electrical Arrangements with Horological Pendulums and Balances.
Inventor: PRIOR ARTHUR VENN
IPC: G04C3/027
Filed: 1909-03-09
Granted: 1910-02-17
Abstract: 5687. Prior, A. V. March 9.. Electric clocks. - A pendulum or balance carrying a magnet or piece of iron is arranged to actuate contacts by magnetic attraction as it swings, by causing to oscillate a suitablypoised mass of iron or magnet near which it passes, or by the induction of a current in a coil within which the magnet may move. Various arrangements of switches operated in this way, comprising spring- or gravity-controlled contacts, or mercury contacts, are described. The electric circuit or circuits so closed may be used to maintain the oscillation of the pendulum in the usual manner, to.govern the amplitude of the oscillations, or to operate dial-work. Fig. 5 shows one method of effecting the closing of an impulse-giving circuit at the correct instant. A mass of iron A on the pendulum passes over magnets B, C pivoted at D, E with their upper ends near together. The magnets carry rigid arms G, F, on one of which is a pin H. As the pendulum swings in one direction, it attracts the magnet B first, which closes the impulse-circuit at the contact K. Both magnets fall back when the pendulum has passed. In returning, it attracts the magnet C first, and the end S of its arm then blocks the arm G and prevents the closure at K. The arm F is shown as having its path limited by a stop Z, but it may close a second circuit for operating dial-work. In the arrangement shown in Fig. 7, a magnet N S carried by the pendulum A moves within fixed coils B, C. The direction of the current generated by the pole N in the coil B and relay electromagnets E, F, as the pendulum swings in a given direction, is such that a contact X Y is closed and the impulse-magnet C energized. The contact is broken, or a second one may be closed to supply a reversed current to the magnet C, as soon as the return swing begins. A device for controlling the amplitude of the oscillations of the pendulum, Fig. 6, comprises a magnet N S mounted on an arm A pivoted in unstable equilibrium at B, the end of the arm A resting on either of the contact screws C, D; an impulse-giving electro-magnet P; electro-magnets K, R to determine the position of the arm A; and contacts I, G closed by the pendulum, the contact G being closed only when the swing of the pendulum reaches the desired limit. When this occurs, the impulse to the pendulum is cut out; but the next time the contact I is closed, the circuit of the magnet P is restored. Fig. 8 illustrates an arrangement for transmitting a current at regular intervals to one or more subsidiary circuits, for the purpose of driving secondary clocks or for giving impulses to the pendulum of the master-clock. The circuit, which is closed magnetically by means of the pendulum, includes an electromagnet E by which a lever C and thereby a ratchet-wheel A are actuated. The ratchetwheel, which may be geared directly to timeindicating dial-work, may carry one or more projections F whereby the contacts T, G of a secondary circuit are periodically pressed together. The contacts are fixed on an insulating- block mounted on the lever C. Alternatively, or in addition, a circuit may be closed at O by a pivoted arm M, the arm being raised and allowed to drop periodically by a cam Q or its equivalent on the arbor of the wheel A. A spring V ensures that the contact is momentary.