US530082A - bliss - Google Patents

Description

(No Model.)

L. D. BLISS. TBLEGRAPH KEY. No. 530,082. Patented Dec. 4, 1894.

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UNITED STATES PATENT OFFICEe i LOUIS D. BLISS, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO CHARLES W. NEEDHAM, OF SAME PLACE.

TELEGRAPH-KEY.

SPECIFICATION forming part of Letters Patent No. 530,082, dated December 4, 1894.

Application iled March 7, 1894. Serial No. 502,760. (Nomodel.)

Toa/ZZ whom it may concern: .Be it known that I, Louis D. BLISS, a citizen of the United States, residing at Washington, in the VDistrict of Columbia, have invented certain new and useful Improvements in Telegraph-Keys, of which the following is a specification.

In the use of the ordinary system of telegraphy, especially Where what is known as the Morse key and sounder is used in transmitting and receiving, it is a Well-known objection that unauthorized persons can read and understand the message being transmitted and received by listening to the sounds made by the key, or by the sounder or receiving device, and this is especially true where a large number of instruments are operated together in the same room, for instance, and they are adjusted and supplied with sufficient batterypower to make distinct and loud sounding signals.

One of the objects of my present invention is to provide means whereby an ordinary telegraphic message may be transmitted and reby authorized persons, but which cannot be ceived in a manner to be clearly understood surreptitionsly read and understood by unauthorized persons. In other words,I provide a practically silent transmitter or key and a receiver which while the sounds are distinct and sharp and of a character to be easily readv and understood when the instrument is in the proper position, they are of such slight volume that they cannot be heard or understood by unauthorized persons.

In my prior application, Serial No. 487,965, tiled October 12, 1893, I have illustrated and described a receiving instrument specially adapted for this classof work, and capable of overcoming the objections stated, as far as the receiving end of the lineis concerned, and the object of my present invention is to provide a transmitting instrument or key which, while it shall conform as nearly as may be to the ordinary transmitter keyin use, shall perform its functions practically noiselessly, so that the signals sent cannot be heard except by the proper person connected with the line.

Further, my invention includes the combination of such a noiseless transmitter and re- 5o ceiving instrument, and as such an instrument is not adapted to be used to callan operator at a station when adjusted for this purpose, my invention further includes some sort of an arrangement whereby `the attention of .the operator may be called to the fact that a signal is to be transmitted.

With these general statements as to the purposes and objects of my invention, it may be considered to consist in a noiseless transmitter key, and the combination with said key of a suitable receiver and signal device, substantially as hereinafter more particularly pointed out.

Referring to the accompanying drawings: Figure l, is a side view of a desk or table, showing an arrangement of devices embodying my invention. Fig. 2, is a plan view of the same; and Fig. 3, is a longitudinal, vertical section through the noiseless key, showing the preferred construction thereof.

The receiving table or desk is shown as comprising a platform A, and au upright A', on which the various instruments are mounted, but this of course, is not essential to my invention, being shown only as a convenient embodiment or arrangement of the parts, and of course can be varied to suit the requirements of any particular case. Supported on this platform is a noiseless key B, 8o and this is connected with the electric circuit in the usual way, by conductors passing through the base of the platform, and arranged also on the platform are the bindingposts c, to which the receiverC, is attached by means of a flexible cord C', or otherwise, and also mounted on the upright is a signal device D, which is also arranged to be operated by the transmitting key, in the manner more particularly pointed out hereinafter.

The transmitter key B, embraces the -usual base-piece B', having ears or standards B2, in which is mounted the key-lever B3, which is under the bias of a spring, as B4, and is provided with the usual knob or handle B5, and an adjustable back-stop B6. In other words, so far the key isv shown in the conventional form, and while I-have illustrated one of the scopes most com mon forms, of course, any other wellknown or equivalent form may be used, to suit the pleasure of the operator. It is usual to provide the back-stop with a metallic or other rest-piece B7, which will. produce a sound when the back-stop comes in contact therewith, but to avoidthis objection and to aid in making the key noiseless, I provide a back-rest B7, of some non-resonant or non. sound-producing material, such for instance,

control the electric current and produce a signal on the line, produces a 'loud and distinct noise, so that the signals can be easily read and understood by unauthorized-persons. in the vicinity of the transmitter, A In order to avoid this, I provide the key-lever with a contact b, which may be of platinum or similar material and provide another contact b', which may be of the same material, and so -support rthe contact, that when the two contacts are brought together to control Ithe electric circuit, practically no noise sha1-l be made which would enable an unauthorized person to ascertain the nature of themessage being sent. 'Vhile various means of supporting this Acontact may be used, I-have found it desirable to have it maintained with considerable rigidity or' positiveness in its tixed or normal position, but still be capable of yielding perhaps to a slight extent, and anyway being supported by a non-resonant or sound-transmittin g support. I have found rubber -to be one of the best materials, and the contact may be supported on a block or mass of rubber and connected directly with the line wire e, but as a refined and more satisfactory means of supporting the contact, I connect it to a flexible conductor E, and coil the conductor between layers of a rubber sheet or fabric f. Thus, I have shownthe contact b', as connected to the end of the conductor e, and the conductor is wound preferablyin a spiral relation between the superposed layers of the rubber fabric or'sheet f,` and in this way not `only does the rubber tend manipulated in the usual way. Not only,

does this permit the`key to operate as a noiseless key, but the somewhat elastic contacts make the manipulation of the key less tiresome t0 the operator. l

While of course, any receiving apparatus can be operated in the usual'way with a key of this character, in order to further carry out the main object of my invention, Ipreferably use a receiver C, which can be of a reduced size, and in which while the sounds or signals shall be sharp, clear and distinct,- so that they can bereadily heard when the receiver is applied to the ear of the receivingoperator, they cannot be understood by unaut-horized persons, and I do not deem it necessary herein to describe the specific construction'of such a device, as it is fullyset forth in my for- .mer application, and as broadly considered,

an ordinary magneto-telephone receiver mayy be used in its place.

As before intimated, it is ,desirable to bev able to call an operator at any 4particular' station lto let him know that communication is desired, and as the receiveudoes not ordinarily give out a sufiicient sound to attract the attention of the operator, some means has to be provided for calling him. It is possible to adjust the receiver C, so that the signals can be heard at a considerable distance from the instrument, and thereby attract the attention of the operator, but as this would require that the receiver should be in the transmitting circuit all the time, it would destroy to a great exten t the purposes and objects ot' my invention, as unauthorized persons could listen and obtain the messages passing through the instrument destined for other stations. In order vto-avoid all these difficulties, vI provide a calling apparatus D, and this is shown as comprising a magnet D', which is arranged in the electric circuit, but which is so wound'that it acts as a sluggish magnet, and'willnot be magnetized by the ordinary currents produced in sending the usual signals, and s6 that its armature D2, would not be fully attracted unless there was an unusual prolongation of the' contin nous current, or dwell in the operation ofthe transmitting key. As, however, such a magnet ton D4, connected by 'fa' pitman D5, to vthe armature D2, and-there is a'check valve D6, controlling 'the 4opening @Land the retracting spring D7, vis so adjusted as'to normally holdthe piston in the uppermost part of the cylinder,o\r adjacent' to the valve. When the coils of the magnet Dare energized, the tendency, of course, is iirstto attract the armature lever D2, and its armature,but it being at this time at the greatest distance from the magnet, not only is the attraction of magnet less, but the dash-pot tends to prevent the j rapid-movement of the armature lever until after a relatively considerable time, longer 'than any ordinaryzsignal to be transmitted ing easily to permit the piston to rise in the cylinder. It will thus be seen that only when there is a prolongedclosure of the circuit made at the transmitting key, so that the 5 magnetism of the magnet D', will be mainand give a distinct signal. It will thus be 'seen that with this arrangement of circuits, not only can a message be noiselessly transmitted by manipulating the noiseless key, but .lc it can'be received so that it will be unintelligible except to the proper person', and the danger of surreptitionsly obtaining knowl. edge of the message sent is avoided. Moreover, the signal circuit is practically inop- 25. erative in the ordinary transmissionof the message, but by holding the circuit closed at the transmitter, a signal may be given to attract the attention of the operator at any desired station, and it will further be observed 39 that when once the piston iswithdrawn or practically so, from the cylinder, a series of short signals or calls can be given before the piston has time to return to its normal position. It will thus be apparent that these in- 3 5 strumentsco-operate with each other in producing a complete, noiseless, or as itmay be termed, secret system of electric transmission and it can be readily applied to any existing lines, without material change, by sim- 4o ply substituting my noiseless key and a practically noiseless sounder or relay.

I have found that the receiver will operate satisfactorily Without the interposition of a local battery-at the receiving station, and it 45 can be placed directly in line in place of the ordinary relay, and the magnet of the signal vdevice .can also' be included betweenthe/t'er- -minals of the main line.'

Having thus described my inventio'niand 5o pointed outthe preferred embodiments thereof,.it will be evidentthat I do not limit myself necessarily to vthe precise construction and arrangement of parts herein set forth, as

they may be varied in detail by those skilled in the art, without departing from the gen- 5 5 eral principles of my invention.`

What I claim" is- 1. A noiseless transmitting key, comprising a" non resonant support, and a contact mounted on the support, substantially as de- 6o scribed.

2. A noiseless transmitting key, comprising a non-resonant contact-support, a contact 'mounted on the support, and a non-resonant contact-stop, substantially as described. 65

3. A noiseless transmitting key, provided Awith amen-resonant contactsupport, comprisingsuperposed layers of fabric with a conductor interposed between the layers, and a contact mounted on' the support, subs'tan- 7o ltially as described.

4. A noiseless transmitting key, comprising a non-resonant contactsupport consisting 'of sup'erposed layers of fabric, a conductor spirally arranged between the superposedlayers, 7 5 and a contact mounted on th'e support 'connected to theconductor, substantially as de.- scribed.

5. The combination with an electric circuit, of a noiseless transmitting key comprising a 8o non-resonant support and a contact mounted on the support, and a 'practically noiseless receiver, both the key and receiver being" connected in said electric circuit, substantially as described. 85

6. The combination with an electric circuit, of a. noise-,less transmitting key, comprising a non-resonant contact support and a contact mounted onY the support, a non-resonant y1 'e.- ceiver included in the circuit, and a retard- 9o ingY signal device also included in lthe circuit, substantially as described.

i7.' The combination with an electric. circuit, of a noiseless transmitting key, cbmprising a non-resonant contact support'and a contact 95 mounted on the support, a non-resonant receiver included in the circuit, a magnet also included in the, circuit, an armaturel forithe.

magnet, and retarding devices connectedto the armature, substantially as'desoribed.-

In testimony WhereofuI. have signed my' name to this-specification in the presenceof two subscribing witnesses. i

Louis n. Buss.

4:rco

Witnesses:

F. C. SCHOFIELD, W. S. CoLL1Ns.-

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