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United States Patent Office.

Francis J. McCarty, of San Francisco, California; Henry A. McCarty, Administrator of said Francis J. McCarty, deceased, Assignor to McCarty Wireless Telephone Co. of San Francisco, California, a corporation of California.

Wireless Telephone

No. 889,031 Specification of Letters Patent.

Patented May 26, 1908.

Application filed December 12, 1906. Serial No. 236,685.

To all whom it may concern:

Be it known that I, Francis J. McCarty, a citizen of the United States, residing at the city and county of San Francisco and State of California, have invented new and useful Improvements in Wireless Telephones, of which the following is a specification.

This invention relates to improvements in wireless telephone systems and apparatus therefor by means of which telephonic messages may be transmitted without the aid of wires or other mechanical intermediate connections between the stations.

The invention consists in a combination of devices whereby vibrations produced by transmission through the medium surrounding the earth without the aid of wires or similar connections.

The invention is hereafter described with reference to the accompanying drawings, in which—the Figure is a diagrammatic view of the transmitting apparatus.

A is a mouth-piece with the usual or any suitable diaphragm extended within it and 2 is a tube into the side of which the mouth piece opens. At one end of this tube is the microphone transmitter as at 3, and at the opposite end of the tube is another transmitter diaphragm 4.

5 represents an induction coil having two primary windings of wires 6 and 7, and in conjunction with these an insulated secondary winding as at 8. The first primary wire 6 is connected through a branch of the wire 6a, and a binding post 9, with the contact screw or point 10, which is adjustable in the non-conducting case within which the diaphragm 4 is fixed, and this diaphragm has the contact 11 corresponding with the contact 10. The contacts may be of platinum. From the binding-post 9, the wire 62 passes into the coil 5 thence passing out of it through wire 6 connects with the battery 12, and thence to the binding post 13 of the transmitter 4.

14 is a condenser interposed between the binding-post 9 and the primary wire 6, and it serves to prevent sparking at the contacts of the transmitter.

The microphone transmitter 3 has the binding-posts 15 and 16 with which the ends of the second primary wire are connected with a resistance interposed as at 17.

In the operation of the device, words spoken into the mouth piece A will cause a vibration of both the diaphragm 4 and that within the transmitter 3, and the vibration of the microphone transmitter being synchronous with the vibrations of the diaphragm 4, the effect produced by the double primary winding of the coil 5 is transmitted through the secondary winding 8 and the discharge points 18 to the aerial conductor in the line shown by the arrow 19 and thence to any suitable receiver.

I have ascertained that any primary of an induction coil which has a second layer of wire wound over it serves to choke off the effect of current in the first primary upon the secondary, if it be suddenly short-circuited and that by connecting an ordinary microphone transmitter across the ends of this second primary, it will vary the effects of the first primary upon the secondary when the mouth piece is spoken into, without the aid of a battery when used over short distances, but to obtain this effect over long distances I usually employ a few battery elements.

Having thus described my invention, what I claim and desire to secure by Letters Patent is—

1. In a wireless telephone, means for intensifying the vibrations from a transmitting device, said means consisting of a transmitting diaphragm with metallic contact points, an opposed microphone transmitter, an induction coil including two primary, and a secondary winding, one of said primary windings being connected with the diaphragm, and the other with the microphone, a local battery, connections there-through with the coil, a spark-gap interposed in the secondary circuit and aerial and ground wires connected with said secondary wire.

2. In a telephone, means introduced into the transmission device, said means including a mouth-piece, a transmitting diaphragm with metallic contacts, and an opposed microphone transmitter, two primary windings connected with the diaphragm and microphone coil respectively, a secondary coil energized thereby, a spark-gap device connected with the secondary coil, through
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