Electrical Device Transmits Striking of Clock
Converting an ordinary parlor, or mantel, clock into a master clock, from which the striking of the gong is transmitted to various parts of the home, may be accomplished by fitting it with a simple electrical device, as shown in the sketch. The general arrangement of the batteries, single-stroke bells, and the contact device within the clock case is shown in [Fig. 1]; a detail of the silk cord and other connections of the contact key and the gong hammer, is shown in [Fig. 2]. This arrangement has been in operation for several years, and has been found practical.
Fig. 1
Fig. 2
The General Arrangement of the Apparatus for Transmitting the Striking of a Clock Gong is Shown in Fig. 1, and a Detail of the Contact Device in Fig. 2
The various rooms to which the striking of the gong is to be transmitted are wired with No. 18 annunciator wire, run carefully behind picture moldings and in corners. Where the wires must be carried through a partition, a ¹⁄₄-in. hole is sufficiently large for the purpose. The single-stroke bells are wired up as shown in the sketch. The number of dry batteries necessary varies with the number of bells in the circuit, and also depends on the length of wire through which the current is carried. A trial should be made with several batteries and more added until the bells are rung properly.
The connecting device may be fitted into the clock case without defacing it by boring holes in its side, and the binding posts are fixed into place neatly. The two sections of the contact key, shown in detail in [Fig. 2], are fastened to the back of the clock case with bolts. The upper member is fitted with an adjustable thumbscrew and is stationary on the bolt fastening. The lower arm is made of covered wire and is pivoted on the supporting bolt. Attached to its lower edge, at the pivot, is a small lever arm. This is connected to the hammer rod of the gong with a silk cord. The length of the cord must be determined by careful adjustment so that it will not hinder the action of the hammer H, but will bring the swinging arm into proper contact with the thumbscrew. The contact should be made at the instant the hammer strikes the bell. The contact of the platinum point of the thumbscrew and the swinging arm must be close, but not too strong. Metal posts or tubes fitted over the bolts, at the points where the arms are attached to the back of the clock case, may be used to bring the arms the proper distance forward in the case, so that they will be in alinement with the hammer rod. The silk cord must not interfere with the action of the pendulum P. To hold the silk cord in place on the hammer rod, drop a small piece of melted sealing wax or solder on the rod.—W. E. Day, Pittsfield, Mass.