US877451A - Means for receiving intelligence communicated by electric waves. - Google Patents

Description

No. 877,451. PATENTED JAN. 21, 1908.

G. w. PIGKARD. MEANS FOR RECEIVING INTELLIGENCE GOMMUNIGATED BY ELECTRIC WAVES.

APPLICATION FILED NOV.12. 1907.

1 I i" I M] all v MW W UNITED STATES PATENTTOFFIOE.

' GREENLEAF 'llITTIEB. PIOKARD, OF AMESBURY, MASSACHUSETTS.

MEANS FOR RECEIVING- INTELLIGEN'CE CONEM'UNICATED BY ELECTRIC WAVES.

Specification of .Letters Patent. I

, Patented JaIi. 21,1908.

Original application filed Align s t 30. 1906. Serial No. 332,697. Divided and application filed November 8. 1906' Serial No. 342.465.

Again divided and this application filed November 12, 1907. Serial 1c. 4.01.856.

To all whom it may concern:

Be it known that I, GREENLEAF Wnrr'rrnn PICKARD, a citizen of the United States of Amer ca, and a resident of the town of Amesbury, State of Massachusetts, have lnvented certain new and useful Imprpvements 1n Means for Recelvlng Intelligence Communivcated by Electric Waves, the principles of which are set forth in the following specification and accompanying drawing, which dis-3 closes the form of the invention which .lnow consider to be the/best of the various forms in which the principles of the invention may be embodied. v

This app'licaticm is a division of my appli cation Serial Number 342,465,1iled Nov. 8, 1906, which was a division ol" my application Serial Number 332,697, filed-Aug 3 0, 1906, and granted Nov 20, 1906 as Patent No. 836,531 5' This invention relates to means for receiving intelligence Communicated by electric waves The object of the invention is to provide a commercially usefulmeans for operating a device for translating the commu'nlcatlons into intelligible form, exclusively by the energy of the oscillatory currents generated by the receipt of the waves. T 0 this end the object is to practically convert the received oscillations into a'form suitable for operating anindicating device, such for example as a telephone receiver, without the use of any auxiliary energy, and without resistance due to conductor-attenuation or imperfect contact.

. Of the drawings, Figure tie adiagrammatic illustration of a wellknownform of wireless telegraph receiving station apparatus, this being the apparatus with which the invention has been actually used. Figs. 2

and 3 are a side elevation and section respectively of the present preferred embodiment of the detector employed in the invention in its present most elhcient form, Fig. 3 being a slightly modified form.

In Fig. 1 the general arrangement is the well-known loop form of wave-interceptor A, A .operatively provided with the usual 'a'djustable capacity C, inductance L ,adjustable in both the wave-intercepter and oscillationreceiving circuits, the inductance-L, adjustable in the wave-intercepter circuit, and the connection of the latter circuit to ground at G.

O In Fig. 1, the circuit L, T, J, CT, L receives the oscillations generated in the waveintercepting loop A, A, the inductance L being adjustable in the oscillation circuit which is well adapted for use with the oscillation receiver or detector of this invention, as it includes the adjust-able condenser C, andthe indicating device T in shunt to this condenser. The device is preferably a telephone receiver and may be any other form of device such as a sensitive galvanometer which will inilicate an abrupt flow of direct current. The receiver or detector should in use be maintained in good electrical connection in the oscillation circuit, and the contactjunction '1 J should be a substantially perfect electrical contact. The lead to the shuntconnected condenser C and the telephone T is taken from the lower end of the inductance L, so that the telephone and its parallel connectedcondenser are in series between the detector and a part of the inductance L which is of lower potential with respect to the ground.

The receiver-or detector of this invention, roughly indicated at T J in Fig. 1. is shown detail in Fig. 2. I are secured an angular metal support 2 and a metal plate 3, provided with binding posts 4, 5 for ,the leads of the oscillating circuit of Fig. 1'. ,One element of the detector is the chuck'which is removably screwed into the plate 3 by the'part 6. This chuck To a wooden base consists of apiece of metal M to which is material N upon a metallic surface, or otherwise; and as shown in Fig. 3, it is s'u'llicient to place the material N in a liquefied mass of fusible metal F Min "a chuck cup 18, provided with a screw 17, so that when the metal F M cools and solidifiesf the material- N will be firmly embedded in, and in good electrical and large-areaed contact with the metal F M. The operative contact-junction (T J of Fig. 1 is located atthe lower end of the than that of the contact between N and M indicating device.

eily wit '1 the member N.

P. The sleeve 7 can slide along the metallic projection 8 which depends from the metallic all 9, the ball formin a ball-and-socket universal joint with the part 10 of thin metal, which is stamped to shapeand secured to the metallic support ,2 so as to complete the circuit. The member 7 of the receiver may be of an conductor which cooperates prop- The member N may be the element silicon, which appears to be most useful either in the massive amorphous or graphitic solid form; or it may be a suitable equivalent which accomplishes the objects of the invention, i. e., a conductor within the scope of the invention which possesses high resistivity and which when operatively in substantially perfect electrical contact with the other conductor, as 7, operates in cooperation therewith to produce a direct current suitable for operating the When ,the member 7 is metallic, as of copper in accordance with this disclosure, and therefore has low resistivity, there is a very substantial difference in the degree of resistivity possessed by the two conductors. When the member N has high thermoelectromotive power in cooperation with the member 7, in addition to high resistivity, or when there is a substantial difference in the resistivity of the two conductors, a considerable part of the energy of the received oscillations is concentrated in the form of Joulean heat, at the contact junction, where it may be converted into a direct .current owing to the cooperative there mo-electromotive power of tlietwo conductors. conductors 7 and. N should be a substantially perfect electrical contact, and this is secured y the spring 11, which presses the two conductors together with suflicient force to exclude substantially all contact resistance and action of a loose -contact or coherer nature arising from the resistance of an imperfect contact, such as to cause the contact to be a substantially perfect one.- Such a perfect contact not only accomplishes the objects of'the invention, but avoids the uncommercial instability of imperfect contacts. The spring 11 also vserves to make good contact between thepart 7' and the pressure to insure a substantially perfect contact. The spring 11 however, cooperatively with the movable part 8, permits the selection by manual adjustment of difl'erent locations of the contact T J, owing, inthis The junction between the massive disclosure, to inequalities of different parts of the operating surface of part N, whereby the pressure of the spring is slightly varied within the limits of perfect contact pressure, so as to slightly vary the area of electrical contact and the sensitiveness of operation under different external conditions of use. In no case, however, is it necessary to continuouslymov'e either 7 or N with respect to each other during operation. The device is most efficient in the form shown, as to-the lower end of part 7 having a substantial roundedsurface in physical contact of considerable. area with part N, but having an extremely small electrical contact therewith. In no case need either member 7' or N possess such attenuation as might thereby generate heat.

'1 am aware of devices in the prior art which employ conductor-attenuation as an essential means of generating heat, and of those which employ the resistance of an imperfect contact as an essential means of generating heat. In this invention however, it is unnecessary to employ either of such means, the action being eflicient in all cases of pairs of conductors included within the invention which cooperatively have highresistivity and are in small-aread v substantially g perfect contact with each other.

In order to obtain the best results, the' 1 above specification should be carefully followed. So far I havebeen able to convert upward of ten percent. of the energy of the oscillations into direct current energy. .The device is therefore an electricalconverter or rectifier. In the preferred form: of this invention the action due to the inherent properties of the silicon member or its equivalent is of extraordinary vigor, as is indicated by the fact that the only energy employed to commercially operate the telephone T is that of the received oscillations. All resistancevarying action should be reduced to a minimum, as by employing the conductors in substantially massive form and inlsubstantially perfect contact with each other, because the energy of the oscillations should not be wastedwithout contributing substantially to effective action.

The remarkable 'fact that the telephone can be operated in a commercial manner, solely by the converted ener of the received oscillations, is explainefb ment that that feeble energy which is re-,

y the stateceived at the ordinary commercial wireless telegraph station is amply suflicient to operate a sensitive receiving instrument, provided that the translation of this ener into the form of a direct current is' efiicient y. ac-

comphshed. It is, ofcourse, necessary in commercial work to effect this conversion,

because there is no known indicating means which'can be sensibly affected by the received energy of commercial long-distance wireless telegraphy when in the form of high frequency oscillations, notwithstanding the fact that a sensitive telephone may, as an experimental feat, be slightly'affected by the oscillations emitted from'a nearby or very powerfulsending station.

'wireless communication is, at the minimum,

of the order of magnitude of one-thousandth of an erg-per dot.. 'l'he. efficiency of the apparatus of this invention, as demonstrated by trial under commercial conditions, is upwards of ten per cent. There is thus ample margin for commercialoperativeness for the least sensitive form of this invention in the case of the present longest distance wireless telegraphy. 1 4

The speed of reception with this invention is unlimited, since it is not only self-restoring to its sensitive state, but this restoration is practically instantaneous because, so far as 4 the thermoelectromotlve actlon is concerned,

the small quantity of heat which is'generated bythe received oscillations comprising a signal is rapidly conducted away, partly by 30 thermal conduction to the metal portion 7, and the remainder b the conversion into an electric current whlch finally expends its energy in the indicating device.

The advantages of the new detector are as follows. It fulfils all re uirements of commercial wireless telegrap y as to sensitiveness, speed, stabilityand freedom from delicate adjustments. I have found that the continued sensitiveness of the detector is in nowise impaired by severe static discharges. It is also simple and cheap in construction.

It is not affected by changes in atmospheric temperature or humidity. Itssensitiveness so far has not beeniimpaired by continuous and continued use. Any portion of any 'oneof the classes of'material having the inherent properties of the conductors included within this invention, makes an operative .con-

tact with another suitable conductor if that contact vbe substantially, perfect. This invention requires no auxiliary source of heat as has been necessary with previous converters designed for,high frequency oscillations. It is an important practicalas well as commercial advantage of this invention that it essentially dispenses with auxiliary I sources of energy, in that such sources, such as batteries and the requisite accompanying potentiometers, areexpensive and require fre uent replacement [here is apparently no imit to the operative life of the detectors included in this invention.

term here meaning. a non-attenuated, non- 'mass.

comminuted solid having a substantially uniform chemicalcomposition throughout the This word massive as used in the claims, does not possess its special mineralogical meaning which may exclude either crystalline form or crystalline structure, because it here includes non-attenuated, noncomininuted solids which may have either such form or'such structure; nor does the word massive, in the claims, possess its special geological meaning of homogeneity as to being destitute of structural divisions such as planes of stratification, because it here includes non-attenuated, non-comminutedsolids which may have cleavage for mations: The only limitations here placed on the word massive are that the material is not a chemical formation on a mere sur face, or a conductor attenuated for the necessary purpose of thereby obtaining necessary heat-producing resistance, and that it is not comminuted to such degree as'to lose its massive character-as and for the. purposes set forth.

Y The expression substantially perfect electrical contact in the claims, means the good electrical contact for the purpose of this invention, that is to say, a contact which has substantially no contact resistance, 11. 0., is not imperfect or microphonic such as might be necessarily employed to result in the generation of heat by means of the resistance of an imperfect contact, or to operate by varying contact-resistance, The substantially perfect contact of this invention is characterized by considerable pressure suflicient toexclude -material imperfection or looseness and substantially all contact resistance due to such looseness, as distinguished from the empirical or definite looseness, or contact "resistance, necessarily employed outside of On the other hand, the two this invention. conductors of this invention are individually separate, and the expression substantially resistance.

The meaning of the adjective non-metal he as used herein, is the commonly accepted one which excludes all metals, alloys or.

chemical mixtures of one metal with another,

and-which includes all non-metal elements, and chemical compounds of non-metals with I metallic substances.

I claim:

. 1. Means for receiving. intelligence communicated by electromagneticwaves, which comprises two substantially massive 'indiyidual electrical conductors operatively in substantially perfect contact with .each

' other, said. conductors having different dehighresistivity,-at least one of which conductors possesses high, resistivity; incombination with a spring which operatively holds the said conductors in substantially perfect small-areaed electrical contact with each other; and a freely movable, non-threaded support for said spring to permit a variation of contact pressure within wide limits of substantially erfect contact pressure, and thereby slig tly vary the area of the minute electrical contact. 7

3. Means for receiving intelligence communicated by electromagnetic Waves, which comprises two substantially massive individual conductors operatively in small-areaed substantially perfect contact with each other, and having different degrees of resistivity and cooperatively having high resist-- ivity, at least one of said conductors having highresistivity; in combination with a mass of good conducting material having a broad surface of intimate contact, relative .to said small-areaed contact, with said high resistance conductor.

'4. Means for receiving intelligence com municated by electromagnetic waves, which comprises a substantially massive conducting solid having low resistivity, and a substantially massive non-metallic solid having high resistivity and also thermoelectromoseparate, but operatively connected tocontact v 5. Means for receiving intelligence communicated by electromagnetic waves, which comprises two substantially massive individual conducting solids, one of which has low resistivity, and the other of which has 7 high resistivity and alsothermoelectrohiotive power; said conductors being operatively connected 'tOgGthGIf'iH' substantially perfect electrical contact.

6. Means for receiving intelligence communicated by electromagnetic waves, which comprises a substantially massive l'ow resistance metalhc member, and a separate substantiallymassive conducting solid having high resistivity; said members being con nected together in substantially perfect electrical contact;'said member which has h gh resistivity having also thermoelectromotive t e power said conductors being individu-. iv

trica trical currents into direct currents, which comprises a substantially massive low resistance conducting solid in substantially perfectelectrical contact but not integral with a substantlally massive conducting solid having high resistivity and also thermoelectromo-- t ve power.

8. Means for receiving intelligence communicated by electromagnetic waves, which comprises two substantially massive individual electr cally conduct ng solids cooperat1vely hav1ng high resistivity and also thermo-electromotive power'; in combination with means for holding said conductors together in substantially perfect contact.

9. Means for receiving intelligence communicated by electromagnetic waves, which com rises two substantially massive electrica 1y conducting solids which are individually separate, but 006 eratively connected together in substantia ly perfect electrical contact, said conductor's cooperativelyhaw ing high resistivity and also cooperatively possessing thermoelectromotive ower.

10. Means for receiving inte 'gence communicated by electromagnetic waves, which com rises two substantially massive electrica ly conducting solids, which are individually separate, but operatively connected together in small-areaed substantially perfect electrical contact, said conductors cooperatively having high resistivity and also cooperatively possessing thermoelectromotive power.

- 11 Means for receiving intelligence com- 'municated by electroma netic waves, which comprises two substantla ly massive electr1c-' ally conducting solids which are individually separateybut cooperatively connected together in siuall-areaed substantially perfect electrical contact, said conductors cooperatively possessing thermoelectromotive power, and having substantially different degrees of resistivity, at least oneJof the conductors having 'high'resistivit I 12. Means for recelving intelligence com municated by electromagnetic waves, which comprises two substantially massive electrically conducting solids which are individually separate, but operativel connected together in substantially pe ect'electrical contact, said conductors cooperativel having high resistivity and also thermoe ectromotive power, and the individual conductors having substantially different degrees of resistivity. o

13. Means for recelving intelligence com-- municated by electromagnetic waves, which complrises two substantially massive elecy conducting solids which are individually separate, but operatively connected together in small-areaed substantially perfect electrical contact, said conductors having substantially different degrees of resistivity, and coo eratively having high resistivity.

14. cans for receiving intelligence com- Inunicated by electromagiietic waves, which comprises two substantia y massive electrically conducting solids which are individually separate, but'o eratively connected together in substantialy perfect electrical contact,

.said conductors cooperatively having high resistivity, at least one of them having high resistivity; a mass of fusible good conducting material in which the "high resistance conductor isembedded; and a receptacle for the fusible conductor.

15. Means for receiving intelligence communicated by electromagnetic waves, which comprises two substantially massive individual electrical conductors of difierent degrees of resistivity and cooperatively having high resistivity, at least one of said conductors possessing high resistivity; in combination com rises two individualmassive electrical com uctors of different degrees of resistivity and cooperatively having high resistivity, at

least one of which conductors has high resistivity; in combination with a supporting member having a telescopic joint with one of said conductors; a spring operatively located. within the telescopic joint to hold the two conductors in substantially perfect contact .with each other; and means to permit the manual alteration of the location of the ("ontact junction of the two conductors.

- GREENLEAI! Wlll'll'llllll l'lhKMtlL Witnesses: 1

EDWARD I-I. RowELL, MYRA S. RowELL.

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