US727328A - Receiver for signaling. - Google Patents

Description

No. 727,328. Y PATENTED MAY 5, 1903..

' R. A. FBSSENDEN.

RECEIVER FOR SIGNALING.

APPLICATION FILED DEG. 29, 1902.

FIELI- IE 1 "DEE l4 1 [ml] gVgTNESSES: QIISVENTOR I AWL- limits dramas Patented May 5, 1903.

PATENT FFICE.

RECEIVER FOR SIGNALING.

SPECIFICATIQN forming part of Letters Patent No. 727,328, dated May 5, 1903. Application filed December 29, 1902. Serial No. 136.967. (No model.)

To (tZZ whout it may concern:

Be it known that I, REGINALD A. FEssEN- DEN, a citizen of the United States, residing at Fort Monroe, in the county of Elizabeth City and State of Virginia, have invented or discovered certain new and useful Improvements in Receivers for Signaling, of which improvements the following is a specification.

The invention described herein relates to certain improvements in receivers for signaling. It -is characteristic of most forms of imperfect coutact-reoeiverse. g., coherers now in usethat theyare formed ofsmallirregular particles of conducting material, so that when brought into contact with each other a surface of one particle may be in contact with a point of another particle, but when decohered and again, brought into contact with each other a surface of one may bear upon a surface of the other. By reason of this variation in the areas of contact the current passing through the coherer will vary, rendering the signals received uncertain. Ooherers have also been used in which the contacting surfaces are uniform; but the same surfaces are always brought into contact again after decoherence. Where the same non-conducting film is constantly acted on by the current, its character is so changed as to cause variations in the voltage required to actuate-the coherer.

The object of the present invention is to insure uniformity and reliability of action of receivers of the imperfect contact type and to insure their freedom from the effects of electrical or mechanical disturbances.

In the accompanying drawings, forming a part of this specification, Figure 1 is a diagrammatic view illustrative of my improved receiving apparatus, and Fig. 2 illustrates a modified form of the apparatus.

In the practice of my invention I employ an imperfect contact-receiver of the self-restoring typesuch, for example, as that shown and described-consisting of the parts or members 1 and 2, so constructed that one shall have movement relative to the other, so that the contacting surfaces can be changed with sufficient frequency to give operative uniformity. Convenientformsfortheseparts consist of a disk and a second member stationary relative to the direction of movement of the disk. The disk is mounted upon a spindle 3, which may be rotated by any convenient means, such as the clockwork 4E. This disk may be formed of carbon or carbonized structured material, such as carbonized velvet, or metal, such as an alloy of gold and bismuth, the latter forming five per cent. of the alloy, or aluminium or mercury or osmium or iron. The other part or member 2 of the coherer may be formed of carbon or metal. Both parts or members may be formed of similar material. When the part or memher 1 is formed of carbon, the part or member 2 is made by preference in the form of a roller mounted so as to bear upon the face of the disk and to be rotated by contact therewith, as shown in Fig. 2. When using this construction, the disk is preferably constantly rotated by any suitable mechanism. As an indicating mechanism a telephone 13 in the local circuit may be used.

It is characteristic of my improvement that new surfaces are c on stantly broughtinto C9111.

wa mth EH1 ptherTtlibhlitactew-i. e., area'ana shape of ni'snrracesnr contact being uniform and similar, so that for each coherence the action is practically the same and that any insensitive position of the contact does not persist on account of the fact that new surfaces are constantly presented. As on account of irregularities in the motion or vibration or surfaces the contacts will never be entirely uniform, and hence in the case, for example, of the rolling contact shown in Fig. 1 irregular noises will be produced in the telephone 13 which will interfere with the signaling, the indicating apparatus is designed so as to respond only to impulses having a frequency equal to the number of electrical discharges per second at the sendingstation-'. e, if at the sending-station there are one'hundred sparks per second the indicating apparatus should respond only to im' pulses of that frequency. This is obtained by tuning the receiving apparatus either electrically, as by putting in the capacity 15 and the inductance 16 in circuit with the telephone 13, as shown in Fig. 2, or mechanically, when the inductances and capacity'may be omitted and a telephone having instead of a diaphragm a tongue in tune to the desired frequency, as shown in Fig. 2, where 18 is a single telephone-magnet, and 19 a metallic tongue adapted to vibrate at the desired frequency.

I am aware that imperfect contact devices have been constructed where one or more of the contacts have been made movable for purposes of adjustment; but the motion herein described does not refer to motion of adjustment which effects a change of sensitiveness by changing the pressure, but of motion for, maintaining the sensitiveness practically without changing and for renewing the surfaces of contact.

The invention is not limited as regards the terms of the broad claims to any specific form or construction of self -restoring imperfect contact-receivers.

I claim herein as my invention- 1. An imperfect contact-receiver for signaling, having in combination two parts or members each having a uniform surface,

means for moving one of said surfaces relative to the other, and an indicating mechanism adapted to respond only to impulses of a predetermined frequency,substantially as set forth.

2. An imperfect contact-receiver for signaling, having in combination two parts or members each having a uniform surface, means for moving one of said surfaces relative to the other independent of the action of the electromagnetic waves, and an indicating mechanism adapted to respond only to impulses of a predetermined frequency, substantially as set forth.

In testimony whereof I have hereunto set my hand.

REGINALD A. FESSENDEN.

Witnesses:

JNO. W. BAILY, '1. L. SCLATER.

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