US294212A - Electric annunciator - Google Patents

Description

(No Model.)

I. H. PARNHAM.

ELECTRIC ANNUNGIATOR.

No. 294,212. Patented Feb. 26, 1884.

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UNITED STATES PATENT OFFICE.

ISAIAH H. FARNHAM, OF PORTLAND, MAINE, ASSIGNOR TO THE AMERICAN BELL TELEPHONE COMPANY, OF MASSACHUSETTS.

ELECTRIC ANNUNClATOR.

SPECIFICATION forming part of Letters Patent No. 294,212, dated February 26, 1884.

Application filed December 26, 1883. (X0 model.)

numbered 281,4;78, for Telephone System and Apparatus, I have; shown and described the annunciator which forms the subject of my present invention, in connection with improved telephoneexchange appliances.

The object I have in view is to produce an annunciator of extreme simplicity and economy in construction. comprising but few component parts, easy to be adjusted, and capable of fully responding to a very weak callingcurrent of either direction. In this annunciator the adjustments are very simple, comprising only two movementsnamely, a to-and-fro movement of the electro-magnet, and also .a rotary movement of the electromagnet.

Figure 1 is a front elevation of the annunciator, and Fig. 2 a sectional side elevation of the same.

The details of construction are as follows:

I A suitable case, A, is fitted with a glass front,

. similar suitable support.

B, and a short distance from the internal surface of the said glass a steel magnet, O, magnetized either permanently or by induction, is delicately pivoted at a in a plate, b, of brass or other non-magnetic material, or in a Immediately behind t-he said support is an ordinary electromagnet, D, which, by means of an adjustingscrew, f, working in a nut or threaded ring, 9, is capable of adjustment to and from the needle, and also may be turned to any required degree on its axis, as shown in dotted lines in Fig. 1, which is a front elevation of Fig. 2.

- The spindle 0 of the adjusting-screw is rigidly attached to the yoke Z of the electro-magnet, and turns easily in the gland d, which is fitted in the recess is of the partition E and secured by the lock -nut e and set-screw s.

The threaded part of the spindle cis provided with a second lock-nut, g, and the head or handle f, in a manner well understood, may also be detachable, for convenience in construction, and be screwed to the spindle. \Vhen the magnet is to be adj ustedforward or backward from the needle, it is only necessary to loosen the lock-nut g, and then push or pull tromagnet, whereby it is enabled to act more or less powerfully on the said needle.- This adjustment is accomplished by loosening the lock-nut g, and then turning the spindle c to the left or right, as may be desired. The needle C may also be slightly weighted, if necessary, at its lower end but this will not usually be requisite, and I do not prefer it, as the sensitiveness of the annunciator is thereby impaired. The electromagnet D may be con nected with any electric circuit by means of the wires h and 11.

One great advantage possessed by my annunciator over others used in telephony consists in the fact that it resumes its normal position as soon as the circuit is opened at the signal-sending point. It is, moreover, capable of responding differently to currents of either direction, a current of given direction producing a deflection to the right, while a current of opposite direction produces a deflection to the left.

Having now described my invention, I claim- An .annunciator consisting of an electromagnet capable of horizontal and rotary adjustment, and provided with a magnetic and polarized needle pivoted in front of or between the poles of the electro-magnet, substantially as described.

In testimony whereof I have signed my name to this specification,in the presence of two subscribing witnesses, this 2lst day of December, A. D. 1883.

ISAIAH H. FARNHAM. Witnesses:

ARDON \V. OooMBs, FRANK S. Wirnnnoosn.

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