Electric Clock
A clock operated by a weight or spring and having a pendulum, which is controlled by electrical currents transmitted automatically by a master clock. 2. A clock in which the winding is performed by electricity, by means of a motor placed in the case. Fig. 95 illustrates the mechanism of an electric clock made by Mr. F. Lorenz, which has many novel features to-recommend it. It consists of a brass, German silver, or other metal back plate A, made sufficiently heavy to support the entire weight of the movement and pendulum in a proper manner. The pendulum, which beats seconds. is supported by an arm B, in the usual manner, and is composed of steel rods CC, held by brass bars DD, and adapted to carry glass jars of mercury, with a rating nut at the lower end, in the usual form. A three-ohm electro-magnet E is suspended from the upper part of the plate as shown, and beneath it is an armature F, which is carried on a pivoted lever having a counter balance weight G, at one end and an impulse weight H, at the other. An adjusting screw is provided beneath the armature to retain it within the influence of the magnet. Attached to the bar D, of the pendulum and oscillating with it, is an adjusting screw I, which receives the blow from the impulse weight H, and imparts the momentum to the pendulum. This weight, which weighs thirteen pennyweights, is suspended from the armature lever by a silk cord, and acts upon the pendulum every 58, 60, 62 or 64 seconds, according to the amount of pressure in the atmosphere. At the lower end of the plate is shown the escapement. The bar J, is carried upon the pendulum rods, and has at its center a pillar which carries a ruby jewel, having a groove cut in its face at right angles to the plane in which the pendulum swings. Beneath this is an oscillating lever L, carried upon an arbor which is fitted in jeweled holes in a pair of upright plates M. This lever is made of gold, tipped with irridium, (the hardest known metal), and has its lower end enlarged to form a disc about the center of the arbor. Upon this disc are placed two guard pins which prevent the uncoiling of the hairsprings. At suitable points in the plate M, are placed two banking pins which prevent the lever from moving too far by striking against the projecting outer ends of the hairsprings. The hairsprings are mounted on the arbor so that one coils to the right and the other to the left, and are so adjusted that the recoil of either will throw the oscillating lever to the same side as that upon which the spring is coiled. Thus, when the jewel is carried past the lever it presses upon it sufficiently to coil one hairspring so that the recoil will reverse the lever. On the return motion, the reverse happens, and this is kept up until the arc of the pendulum has decreased so much that the jewel is no longer carried past the lever. When this occurs, the irridium point of the lever enters the groove of the jewel and the momentum of the pendulum pushes the plates M and the spring bar K downward, out of its path, thus making electrical contact between the spring bars K and N, and closing the circuit, which operates the magnet E, the armature F, and the impulse weight H, and gives renewed impulse to the pendulum. Attached to the center of the pendulum bar D, is a lever Q, carrying at its lower end a roller jewel which works in the fork R, to operate two pawls which are hung eccentrically upon the fork arbor, and actuate a ratchet wheel S, with 30 teeth. The ratchet wheel arbor carries on its outer end a pinion which meshes with the hour and minute wheels in the usual manner, and also bears the seconds hand. As the length of the pawls is such that the ratchet wheel moves one-half tooth at each vibration of the pendulum, this gives a center-seconds motion direct from the ratchet wheel arbor. The clock is operated by two cells of sal ammoniac battery, the wires from which enter the case and are passed behind the back plate by means of binding screws as shown.
The current enters on the wire T, and is conveyed to the spring bar K, through the insulated arm as shown. This arm, which carries the oscillating lever L, is adjusted so as to remain 3 mm. from the arm N, which is similarly insulated and from which runs the wire O, connecting with the magnet E. A wire P, is connected with an adjusting screw which presses upon the bar N, and the points of contact upon the bars K and N are tipped with platinum. When K is depressed by the pendulum acting on the lever, the circuit runs through T, K, N, P and O for about 01 second; then as the depression continues, N is removed entirely from the contact with P, and the entire current follows the line T, K, N, O. This prevents sparking between K and N, and also prevents induced currents in the magnet. The important feature of this clock, aside from its simplicity, is that the arc of the pendulum cannot decrease beyond that for which it is adjusted, as the action of the impulse weight and oscillating lever cannot vary, which feature renders the timekeeping qualities of this clock far superior to that of any weight clock.