US960495A - Current-reinforcing means. - Google Patents

Description

R. C. BROWNE. CURRENT REINFORCING MEANS. APPLIOA'HN FILED MAY 25, 1907.

Ptented June 7 es es.'

'RALPH C. BROWNE, OF SALEM, MASSACHUSETTS, ASSIGNOR T0 JOHN ABBOTT, OF WINCHESTER, MASSACHUSETTS.

C"UBRENT-EtIEINIEORIGIN-Gr` MEANS.

augmenting the energy in the varying cur-r rent circuit, by adding thereto and in synchronism therewith, additional energy derived from a battery or other electricalgenerator. In telephony practical resultshave been secured in instruments of this character by causing the current, to be reinforced in 4the telephone circuit, to act upon a diaphragm through the agency of the variable receiving magnet, which diaphragm is connected to an electrode'between which and a second fiiged electrode is placed the variable resistance medium.' Said electrodes and said resistance mediumv are arranged in series in a' local lbattery circuit, so that when the diaphraglufis vibrated,'it causes fluctuations in the local -or battery circuit in synchronism with the fluctuations of the current in the telephone circuit.. In instruments such as described, the diaphragm is madeof magnetic material which is fairly rigid and heavy, and its inertia must be overcome by the magnetic field -induced by the telephone current acting on the variable receiving magnet before the vdiaphragm is vibrated. The electrode which isaifixed to the diaphragm to movel therewith, adds to the A weight which must be moved by the magnet,

and if, as in most cases, it is made of pol-A ished carbon .or like material, it is apt to become roughened and less effective. Tele phone currents are feeble at best, and they grow weaker with the length of the telephone line in consequence of the increasedv resistance thereof and of leakages and other losses. On account of the feebleness of the current in a telephone circuit, the'diaphragm and the electrode connected thereto, have a very slight. movement, and the two electrodes therefore must be brought very close Specification of Letters Patent.

together sothat the pressure 'on the resistance medium may effect even a small part of the dead resistance between them. The closer the electrodes are brought together, the lower the resistance of the intervening medium, and the possible range of the instrument is correspondingly limited. The close adjacency of the electrodes kgreatly limits the amount of battery power that may be 'employed `'without such harmful results as burning or heating etc., and moreover, the closer the electrodes are brought together, the greater isth'e danger of the re sistance medium packing,

The objectof this invention is to improve such current reinforcing or renewing means by increasing their sensitiveness and their range of action, and by enhancing their efficiency, and durability. This is accomplished by employing in conjunction -with a variable magnet arranged in the telephone circ'uit or sequence of circuits, an armature or movable pole piece operating upon a thin resistance medium 'through which the current flows between electrodes so placed that the path of the current is substantially at right angles to the lines'of pressure of the armature o1" movable'pole piece upon the resikstanee medium. The two electrodes are stationary and neither of them. is carried by the movable pole iece or armature, -nor vibrated by the laction thereof. The resistance medium, which is preferably carbon in a comminuted form, is arranged in a thin layer between insulated retaining walls, of which one or both may be made of light Hexible material, such as mica or other suitable substance. Thus .I dispense with the employment of a magnetic diaphragm and the necessity of overcoming its inertia. By arranging the resistance medium `in a thinlayer, as described, and employing stationary electrodes, I secure the greatest possible scnsitiveness in the resistance medium, and.

Patented June 7, 1910.

Application filed May 25, 1907, Serial No. 375,573.

On the accompanying drawings,-'Figurc l 2 scones 1 represents diagrammaticallythe electric connections of the reinforcing instrument,

associated with a telephone circuit at animtermediate point thereof. Fig. 2r epres`ents a magnified section through the receptacle containing the variable resistancemedium..

Fig. 3 represents a magnified vertical section of another form of lnstrument embodying the invention.

The 'electrodes and the variable 'resistance medium to be hereinafter described aredesigned to be` connected in a main circuit 10,

as illustrated conventionally in Fig. 1, said main circuit including a'battery or source of power. as at 11. The magnetizatio'nvarying coil b .is arranged to be connected with another main circuit section 12. 'In the circuit 10 may be included the primary windings 13 13 of induction coils, the secondary windings. 14 14 of which are included in the main telephonecircuit 15. As..

illustrated, the apparatus is'shownv as being placed in the middle of the circuit 15 the which includes the coil b is in position to be operated from either end of the telephone circuitor s aid sections 17 17 there being inv the section 15 at eaclil end, areceiver 20.

The telephone currents passing through the-'coil b cause a variation in the field of the variable magnet so that the pole pieces a a2 are attracted 1n accordance with Such variation, to effect a similar variatlon in thecompression of the resistance medium. Consequently telephonie currentsv synchronous with those in the main circuit 15, are set up in the circuit 1.0, and by reason. of the coils 13, 13 iniductive relation to the coils 14, 14, the telephonie currents inthe main telephonic circuit are renewed or reinforced in a manner now well understood.

In Figs. 2 and 3 I have illustrated an embodimentof the invention in which I employ a magnet e of the horse-shoe type. This has the parallel arms e e which are apertured to receive the inwardly extending pole pieces f which are formedy of tubular magnetic material, such as soft iron. Upon these pole pieces-are supported the spools g of two magnetization-varying coils g g Whose axes are in alinement. These two coils may be placed inseries in the main telephonie circuit or in ,one of the sectins thereof, as

`for instance in the brid e 12. 4Between the adjacent ends of the co s is. placed a receptacle h of substantially the construction shownlsin Fig. 2. Said receptacle contains a thin layer@ of a suitable resistance medium suchv asgranular carbon, with separate staf tionary electrodes d d arranged in a line transverse to the axes of the coils. layeris preferably about one-tenth of an inch in thickness, and the retaining walls c c are preferably thin' (say .-001 of an inch in thickness) and have smooth4 surfaces. indthat .micais an excellent -material`for 75 these walls:A Said walls are spaced apart by' an intervening frame c2 of insulating ma- 'terial` to which they. are clamped lby outer frames c3 03, and the frames or walls 'consti-ff tute -a chamber or receptacle for the resist- 8e.. ance of the medium. 'The electrodes may consist vof stampings of this metal foi'l (preferably platinum) which are pointedat their ends, and they are supported by the framec2 so as to centralize or focus the flow of current through the variable resistance medium in lines transverse tothe axes or median 'lines of the pole pieces i z'. The receptacle is mounted upon a support attached to a l neutral point ofthe ma net e, said support 9'0 comprising the two memers j jvclamped .to-4 gether by a screw j to receive and rigidly support Said receptacle. lAttached to the outer .faces of the two flexible retaining walls of the receptacle, are two movable polepieces i z' arranged with their axesin alinement with the axes of the pole pieces f f, but out of contact therewith as shown. The movable pole pieces z' z' are formed of light tubing having solid'bos'ses or inner endsv 100 and have but little inertia. The movable pole pieces are attached in any suitable manner tothe retaining walls, but I find that with advantage they may be cemented to a facing of fine or delicate silk fabric which is in turn cemented to said walls. By reason yof magnetic induction, the pole pieces become magnetized more or less, according to; the strength of the magnet e, and" thereby attract each other with a certain force to cause the variable resistance medium to be compressed more or less. When the telephonie current passes through the coils' g g,-the magnetic ieldis either increased or decreased thereby causing a variation in the force with which said pole pieces z' i attract each other. The pressure u on the resist'- ance medium is effected direct y against both faces thereof by the variation in the telephonic current, and as said medium vis-ina very thin layer with the electrodes widely separated, thegreatest possible microphonic action -is had, and a` maximum electromagnetic force is utilized for reinforcing the telephonie currents in the main telephonie circuit. The electrodes which are in contact with the variable resistance medium are separated a distance several times greater than the thickness ofthe layer of the variable resistance medium, and the resistance of The 7o the medium may be as great or greater than the line resistance of the battery circuit.

I have not attempted to show the parts in their relative dimensions, as these will Vary according to circumstances, nor have I 'attempted to describe themodications of the apparatus inl which the invention may be embodied. It Will be understood by those to Whom this speciticati'on is addressed,that the illustrated details of construction and arrangement may be greatly varied Without departing from the spirit and scope of the invention, that the l reinforcing means herein described and claimed may be employed for reinforcing all kinds of Varying currents in electrical systems for the transmission of intelligence, and that the phraseology which I employ is for the purpose of description arid not of limitation.

Having thas explained the nature of my said invention and described away ofjconstructing and using the same, although Without attempting to set forth all-0f the forms in which it ma be made, or all of the modes `of its use, Iydeclare that What I claim is -v y l. A current retransmitting and reinforcing apparatus comprising a variable magnet having opposing fixed pole pieces; a receiving or magnetization-varying coil around each pole `of said magnet for 'varying` its field; a variable resistance medium; opposing movable pole pieces or armatures in the eids ofA said fixed pole pieces to impart pressure to both sides or facesof said resistance medium; and electrodes for said resistance medium arranged in a line transverse to the lines of pressure of said movable pole pieces on said resistance medium.

2. A current retransmittingand reinforcing appara-tus, comprising a variable magnet having opposing fixed pole pieces; a receiving or magnetization varying coil around each pole of said magnet for varying. its field; a variable resistance medium; opposing movable pole pieces or' armatures in the fields of said fixed pole pieces' to impart pressure to both sidesor faces of said resistance medium; a. receptacle for said resistance medium, and a iiXed support' for said receptacle..

3. A current retransmittingand reinforcing apparatus, comprising a variable magnet having opposing fixed pole pieces; a receiving or magnetization -varying coil around each poie of said magnet for varying its ield; a variable resistance medium; opposing movable pole pieces .or armatures in the fields of said fixed 'pole ieces to impart pressure to both sides `or aces of said resistance medium; said pole pieces all being arranged in axial' alinement; electrodes mountedv in a linetransversetothe axes of said pole pieces; and a receptacle for receiving and supporting said resistance medium and said electrodes.

In testimony vwhereof I have affixed my i signature, inpresence of two witnesses.

RALPH C..BROWNE.

wWitnesses MARCUS lB. MAY, E. BATCHELDER

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