Page:United States patent 714246.pdf/4

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United States Patent Office.


Harry Shoemaker, of Philadelphia, Pennsylvania, Assignor to Marie V. Gehring and American Wireless Telephone and Telegraph Company, of Philadelphia, Pennsylvania.
Wireless Telegraphy.

Specification forming part of Letters Patent, No. 714,246, dated November 25, 1902.

Original application filed October 25, 1901. Serial No. 79,959. (No model.)

To all whom it may concern:

Be it known that I, Harry Shoemaker, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and 5State of Pennsylvania, have invented certain new and useful Improvements in Wireless Telegraphy, of which the following is a specification.

This invention relates to improvements in 10wireless telegraphy, and has special reference to an apparatus in which static induction is used for operating the receiver.

Another object of my invention is to dispense with the Hertz oscillators now so 15generally used and also the imperfect electrical contact or coherer.

Another object of my invention is to dispense with the Hertz oscillators now so generally used and also the imperfect electrical contact or coherer.

Another object of my invention is the provision of a system which employs two ground connections at each station, although a ground 20and an air wire may be employed, if so desired.

Another object of my invention is the provision of a system which is easily tuned, so that any number of apparatus may be 25operated at the same time without in any way way affecting the other.

Another object of my invention is the provision of a transmitting apparatus in which is employed an alternator and a transformer 30which cause vibrations to pass through the earth or air to the receiving apparatus, which is provided with means which are positively operated to effect a relay and sounder, thus dispensing with the Hertz oscillator and the 35coherer.

To attain the desired objects, the invention consists of a system of wireless telegraphy embodying novel features of construction and combination of parts, substantially as 40disclosed herein.

In the drawings, Figure 1 is a diagrammatical view of the entire system. Fig. 2 is a sectional view of the receiving means, and Fig. 3 is a bottom plan view thereof. Fig. 4 45is a digrammatical view of the entire system using a ground and an air conductor at each station.

Referring to the drawings, A designates the transmitting apparatus, and B the receiving 50apparatus.

The transmitting apparatus consists of the alternator 1, to which is connected the primary of the transformer 2, a key 3 being employed to control the current through the wires connecting the two. Connected to the55 secondary posts 4 of the transformer are respectively the ground-wire 5 and the wire 6, to which is further connected the condenser 7, having the wire 8 connecting it to the ground at 9. If it should be desired, an air60 connection may be employed and is placed as shown in Fig. 4.

The receiving apparatus consists of the ground 11, to which is connected the wire 12, which is connected to the batteries 13, a wire65 14a connecting these batteries to the cap 14, which clamps and holds the ferrotype-diaphdram 15 in place. Secured to this cap is the rubber cap 16. The wire is also connected to the diaphragm.70

Mounted upon the posts 17 is the strip 18 of mica or any resilient insulation material. It is so mounted as to be free to vibrate at a certain period or pitch, depending upon its length. Carried by this strip by means of a75 post 19 is a metal plate or disk 20, which is also free to vibrate with said strip. Connected to the strip and also with the post 19 by means of a wire 21 is a spring-pointer 22, which is connected to a post 23, so as to have a80 slight spring motion, and upon its free end is carried the double-headed contact-point 24, which is adapted to always slightly contact on of the points 25 or 26, which with the wires 27, battery 28, relay 29, wire 30, and85 pointer, make a circuit. An adjusting screw 31 is used to vary the pressure of the spring-pointer. 32 is a non-inductive resistance which takes up self-inductance of the relay. The armature 33 controls the sounder 3490 through its circuit 35 as contact at 36 and 37 is made. A ground-wire 38 is connected to the post 19, and, if desired, an air-wire 39 may be employed.

From the foregoing description, taken in95 connection with the drawings, the operation is readily understood; but, briefly stated, it is as follows: As the source of electricity here employed is an alternator, the same is continuously operated, the key keeping the 100cur-
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