US1224343A - Wireless telegraphy. - Google Patents

Description

1. 0. wmxmsQ WIRELESS TELEGRAPHY. APPLICATION FILED JULY 28. 1915.

1,224,343. Patented Maj1,1917. I

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WITNESSES: J. 0. M; wn/Vs ATTORNEYS.

UNITED STATES PATENT OFFICE.

JAMES O. WATKINS, OF SAN FRANCISCO, CALIFORNIA. ASSIGN OR TO FEDERAL TELE- GRAPH COMPANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALI- FORNIA.

WIRELESS TELEGRAPHY.

Patented May 1, 1917.

Application filed July 28, 1915. Serial No. 42,301.

To all whom it may concern:

Be it known that I, Janus O. YATKIXS, a citizen of the United States, and a resident of San Francisco, county of San Francisco. State of California, have invented certain new and useful Improvements in Wireless Telegraphy, of which the following is a specification.

The invention relates to a receiving system for wireless telegraph and especially to a device adapted to be used in said system.

An object of the invention is to provide an apparatus by means of which continuous electrical oscillations of high frequency are converted into continuous oscillations of lower frequency.

The invention possesses other objects and advantageous features, some of which, with the foregoing, will be set forth at length in the following description, where I shall outline in full that form of the invention which I have selected for illustration in the drawings accompanying and forming part of the present specification. In the drawings I have shown only one specific form of the apparatus of my invention, but it is to be understood that I do not limit myself to such form, because my invention may be em-' bodied in a multiplicity of forms. each being a species of my said invention. It is also to be understood that by the claims succeeding the description of m invention, I desire to cover the invention in whatever form it may be embodied.

Referring to said drawings:

Figure l is a top or plan view of one form of the apparatus of my invention.

Fig. 2 is a vertical section taken on the line A-A Fig. 1.

Fig. 3 is a diagrammatic representation of a wireless telegraphy receiving circuit,

showing the apparatus of my invention arranged therein.

Fig. 4 is a diagrammatic illustration of the effects produced by the operation of the apparatus.

The frequency of the oscillations of the electric impulses in a wireless telegraphy system employing substantially continuous undamped waves, is so high that they cannot be directly utilized to operate electro magnetic instruments, such as telephone reccivcrs, toproduce audible signals. The.

frequency .of the received oscillations is above the limits of audibility and to be received by the ear, the frequency must be reduced to within the limits of audibility. This has been accomplished heretofore by arranging an interrupter and a condenser in the receivingcircuit, the condenser being chargedby' the high frequency oscillations during the time that the interrupter is closed. and discharging with a surge through the telephone receivers when the interrupter is open.

In accordance with the present invention, the high frequency current is converted into a low frequency current. and the telephone receivers are operated by the latter current, The receiving circuit is opened and closed at a frequency which may be made to approach synchronism with the frequency of the received oscillations, thereby producing a low beat frequency. The regularity of the beat frequency gives a musical note to the received signals and the nearer the frequency of interruption approaches the frequency of the incoming waves, the lower will be the note. In Fig. I I have shown diagrammatically the incoming undamped oscillations of high frequency 2. The frequency of interrimtiou is somewhat less than the frequency of the,- waves, resulting in beat frequency oscillations3, which are of much lower frequency than the incoming waves.

The apparatus of my invention comprises a suitable base 4, upon which is mounted a metallic standard 5. Secured to the standard 5 is a holder 6 having a resilient shank 7. Horizontally disposed in the holder 6 is a bar 8 which constitutes the base of the string or wire holder. Passing through the standard 5 is an adjusting screw 9 which bears against the holder 6. and by turning the screw the position of the bar 8 may be varied.

Secured to the bar at one end is a block 12 to which one end of the wire 13 is secured, and at the other end of the bar is a slotted post l-l through which the wire passes. The other end of the wire is fas tened to the key 15 engaging in the end of the bar. Adjacent post ll is a second slotted post 16 having a roller 17 under which the wire passes arranged in the slot. Between the posts and guided thereby is a means for varying the tension f the wire. This means consists of a wedge shaped block is guided by the posts 14 and 16 and being movable against the wire by the thumb screw 19 passing through the bar 8.

The wire is vibrated by means of a smooth edged disk 21 which rotates in interrupted engagement with the wire. The point of contact of the disk and wire is arranged -with relation to the wire. so that it occurs at an anti-node of the desired harmonic. The wire adheres to the disk as it rotates and is stretched out until the curvature of the disk allows it to slip back to its former position, where it is again caught by the disk and the action repeated. Vibration of the wire will, therefore, be maintained and the wire contacts with the disk at the frequency of its vibration. The axis of the disk preferably lies in the same horizontal plane as the wire and the disk is rotated in such direction that that side of the disk which contacts with the wire moves upward.

The disk is placed in contact with the wire at a. point midway between two successive nodes or in other words, at a point exactly one-half the distance between two nodes. Means are, therefore, provided for adjusting the point of contact with relation to the adjacent nodal points. This 'adjust ment is accomplished by means of the sliding bridge 22 which rests on the bar 8 and which engages the wire. A thumb screw 23 is provided for sliding the bridge along the bar 8. After the proper position of the bridge is found which produces the proper distance between the disk and the effective end of the wire, tuning may be accomplished by varying the tension of the wire by means of the screw 19 or by var ing the pressure of the wire against the dislz by means of the screw 9. The disk is rotated by a motor 24 which is insulated from the wire 13.

I have found that the adjustment of the apparatus usually holds better if the disk is not rotated exactly at right angles to the wire, but preferably at an angle of about with respect thereto.

The device is placed in the receiving circuit in series with the telephone receivers 25 the wire 13 being connected in the circuit by means of the binding post 26 and the disk being provided with-a brush 27 connected to the other side of the circuit. The incoming high frequency currents pass through the disk and wire in series and are interrupted at the frequency of the harmonic producing a beat wave of low frequency which passes through the telephones.

The disk, which is preferably made of phosphor bronze, bears lightly against the wire, which is preferably of steel. The edge of the disk, which is preferably rounded, should be very carefully polished with crocus cloth and should be kept clean and dry in order that the frequency of interruptions may be constant. It is essential also that the edge of the disk be concentric with its axis of revolution.

By making the frequency of vibration of the wire equal to the frequency of the oscillations, the device may be employed as a rectifier.

I claim:

1. In an apparatus of the character described, an electric circuit, a stretched wire mounted to vibrate and a smooth edged r0- tatable disk in contact with said wire said wire and said disk being connected in series in said circuit. 1

2. In an apparatus of the character described, an electric circuit, a wire mounted to vibrate and a smooth edged rotatable disk in contact with said wire at an antinode said wire and said disk being connected in series in said circuit.

3. In an apparatus of the character described, an electric circuit, a stretched wire mounted to vibrate and a smooth edged r0- tatable disk in light contact with said wire at an antinode adjacent the end of the wire said wire and said disk being connected in series in said circuit.

4. In an apparatus of the character described, an electric circuit, a stretched wire mounted to vibrate, a smooth edged rotatable disk in contact with said wire and means for varying the tension of said wire said wire and said disk being connected in series in said circuit.

5. In an apparatus of the character described, an electric circuit, a stretched wire mounted to vibrate, a smooth faced rotatable disk in contact with said wire at an antinode and means for varying the tension of said wire said wire and said disk being connected in series in said circuit.

6. In an apparatus of the character described, an electric circuit, a stretched wire mounted to vibrate, a smooth edged rotatable disk in contact with said wire and means for varying the pressure of the wire against the disk said wire and said disk being connected in series in said circuit.

7. In an apparatus of the character described, an electric circuit, a stretched wire mounted to vibrate, a smooth edged rotatable disk in contact with said wire at an antinode and means for var ing the pressure of the wire against the dis said wire and said disk being connected in series in said circuit.

8. In an apparatus of the character described, an electric circuit, a stretched wire mounted to vibrate, a smooth edged rotatable disk in contact with said wire and means for varying the vibratory length of said wire said wire and said disk being connected in series in said circuit.

9. In an apparatus of the character described, an electric circuit, a stretched wire mounted to vibrate, a smooth edged rotatable disk in contact with said wire at an antinode and means for varying the vibratory length of said wire said wire and said disk being connected in series in said circuit.

10. In an apparatus of the character described, an electric'circuit, a stretched wire mounted to vibrate, a smooth edged rotatable disk in contact with said wire at an antinode adjacent one end of the wire and means at the same end of the wire for varying the vibratory length ofthe wire said wire and said disk being connected in series in said circuit.

11. In an apparatus of the character described, an electric circuit, a stretched Wire mounted to vibrate, a smooth edged rotatable disk in contact with the wire at an antinode, means for varying the tension of said wire and means for varying the pressure of said wire against the disk said wire andsaid disk belng connected in series in said circuit.

12. In an apparatus of the character described, an electric circuit, a stretched wire mounted to vibrate, a'smooth edged rotatable diskin contact with said wire at an antinode,

- means for varying the vibratory length of said wire, and means for varying the tension of said wire said wire and said disk being connected in series in said circuit.

13, .In an apparatus of the character described, an electric circuit, a stretched Wire mounted to vibrate, a smooth edged rotatable disk in contact with said wire at an antinode means for varying the vibratory length 01% said wire and means for varyin the pressure of the wire against the disE said wire and said disk being connected in series in said circuit.

14. In an apparatus of the character described, an electric circuit, a horizontally disposed stretched wire mounted to vibrate and a smooth edged disk rotatable about a horizontal axis lying in the same horizontal plane as the wire, in contact with said wire at an antinode said wire and said disk being connected in series in said circuit.

In testimopf whereof, I have hereunto set my hand at onolulu, Territory of Hawaii, this 10th day of June, 1915.

JAMES O.- WATKINS.

In presence of- G. A. CUNNINGHAM, W. Y. Nommr.

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