US2136337A - Electrical apparatus - Google Patents

Description

Nov. 8, 1938. J. L. GREEN ET Al.

ELECTRICAL APPARATUS Filed June 5, 1937 w f l Y R. www E mi w mw .7 www Z/U www 4 F 5 )MMX- 3.3M/

ATTORNEY.

I Patented Nov;l 8, 1938y James L. Green, Cleveland, Ohio, and Frederick T. Hicks, Detroit, Mich., assignors to The Indemse Corporation, a corporation oi.' Michigan ,Application cime s, 193i, serial ivo. 146,614

Y11 chants.` (o1. ris-36s) Our invention pertains to electrically operated contactless vibrators and systems for operatin and utilizing ,the same. y A

It is an object of our invention to provide electro-magnetically operated vibrators which' are especially useful as radio B power units forenergizing luminous signs, producing musical tones, and musical notes, as frequency standardsand for many other applications requiring long life and permanent adjustment by eliminating me,- chanically engaging contacts with the accompanying wear, clatter, corrosion, and areing.

It is also an object of our invention to provvide a contactless vibrator actuated by'a/coil of a conductive metal which variesits resistance in accordance with the intensity of the electromagnetic ileld in which it is exposed.

It is a further object of our invention to prqvide such a contactless vibrator having means for periodically varying the, iield intensity comprisingI an armature member which is moved by the ux from the winding for pulsating the field in which the winding is exposed.

Another object of our invention is to provide such a contactless vibrator wherein the eld structure comprises a vcore and an enclosing shell arranged to deiine seriestconnected air gapsl and having the energizing winding dis. posed acacent one of the air gaps and the armature adjacent the other `air gap A further objectief our invention is to provide such a contactless vibrator comprising a current inverter for inverting iromdirect current.

The novel features which we consider charac-- teristic of our invention are set forth with particularity in the yappended claims. tion "itself, however, bothas toits organization and its method of operation, together with additional objects and ,advantages thereof. will best 4a be understood from the following description of specific embodiments', vwhen read in connection with the accompanying drawing, in which:

Fig. 1 is a longitudinal sectional view showing the construction of thecontactless vibrator;

Figa 2 is a. diagrammatic view representing the device in connection with `associated circuits for operating and utilizing thesame;

Fig. 3 is a longitudinal sectional .View showing another embodiment ofthe vibrator;

Fig, 4 is an elevational view ofthe armature4 support; and

. Fig. 5 is a diagrammatic view owing a sys,- tem utilizing thedevice? y A Referring more particularly to` Fig. 1 of the drawing. our contactless vibrator comprises a shell I which is of iron or other ferro-magnetic material of low magnetic reluctance, of \cast or sheet construction. The shell I which is pref erably of circular cross-section, is provided at one end with an enlarged annular collar 3 for 5 receiving` and supporting a cap 5 of magnetizvable material. The collar 3 isv precisely tapered and ground to fit snugly into an annular recess 'I in the edge of the rim 9 of the cap in order to provide a close coupled magnetic joint.` The 10 outer surface of the collar 3 is threaded for cooperatively engaging the outer wall of the recess I inthe cap, which is suitably threaded.

The lcap is thusV firmly secured on one open end of the shell I, where itis a closure and serves to 15l continue the magnetic flux path.

A pole II of magnetizable material is mounted on the inside of the closed end of the cap and it extends into the shell to' continue thelow reluctance flux path therein. The pole II is sub- 20 stantially ilat atits inner end,l and it may be integral therewith,l or secured thereon as by welding for examplel- An armature I34 is movably supported adja, cent the inner end of the pole II on a spring 25 support, I5 which is clamped between the outerI end of the shell and thev cap. The armature= support comprises a flat resilient diaphragm like member; preferably non-magnetic, with "apertures to minimize air damping. The armature 30 is secured to the support in any suitable manner as by rivetinggand opposite sides ofl the armature are of unlike `c onior1'11ations.v As shown, the inner side of the amature' I3 lis a tapered cone like conformation which is cut o' at at the 35 inner end .like a truncated cone, for a purpose tobe subsequently. described. The shape, size and weight of the armature and the rigidity of its support may be suitably selected for prede-` termining its vibrating frequency. l 40 Enclosed andsupported by the shell I is a core I9 which/is provided 'with an electrically conductive coil or solenoid winding 2|, for magnetizing the. eldstructure ofthe vibrator. 'I'he core fi 9 is covered withl a layer or tube 23 of in'- 45 sulating material and insulated conductor is f woundAV thereon'. The coil is held together` and secured in place b'yfmeans of suitably insulated annular disks 25 in theV usual manner. A a flange 21 projects inwardly in the shell for'abut- 50- ting and holding the inner end of the coil when 'l it is inserted into the shell. The terminals 28 of thecoil 2i are extended from the shell tlirough g suitable bushins #I in the side wall of the shell I`as will be understood.

Although the coil or solenoid winding may be Wound on the core and secured in the usual manner, the electrical conductor which cornprises the coil is made of a special metal that provides an important characteristic in the operation of the contactless vibrator, as will subsequently be more fully set forth.

The end of the core i9 adjacent the amature is provided with a conical recess 28 similar in conformation to the adjacent side of the armature which moves therein. g

At its other end the core i8 is recessed axially to receive a pin 3i projecting from a plug 33 of brass or other non-magnetic material. Being of a cross section similar to the core I 9, the nonmagnetic plug 33 fits into the coil 2i where it serves to secure the outer end of the core spaced from the end of the coil. The plug 33 is on a closure disli 35 which closes the end of the shell i in which it is preferably secured by external threads engaging corresponding threads on the inside of the shell. The disk 35 is also made of non-magnetic material in order to provide an appreciable air gap for the magnetic flux to pass through the turns of the'winding 2i between the adjacent ends of the core I 9 and the shell I.

it will be seen that the held structure of our contactless vibrator comprises the shell I, cap 5, pole il and core i9 which together dene a low reluctance flux path having two air gaps in series relation as at A and B. The armature I3 is disposed in one oi the air gaps, at A and it is so mounted that it can move axially therein.

Because of its unliise conformation on opposite sides, corresponding to the adjacent ileld structure, and because of its interiltting relation the movement of the armature I3 toward the core |S increases the total air gap, and reverse movement decreases the total air gap.

Because of the disposition of the solenoid lwinding 2l around the second air gap B, the coils of the winding are exposed to the varying iiux passing between the adjacent ends of the core and the shell.

For winding the magnetizing coil, an electrical conductor is provided of metal which varies its resistance according to the intensity oi the electromagnetic iield to which it is exposed. Such electrical and magnetic properties are found in cadmium, bismuth, zinc, silver and other metals and alloys in which the resistance increases when the intensityY of the electromagnetic field is in creased. Such metals we term ohmomagnetic. In our contactless vibrator we expose a coil of such ohmomagnetic material, in the second air gap B which provides the maximum exposure to the varying ux. For this purpose we preferably use bismuth, either pure or alloyed. At times` it is necessary to make only a part oi' the coil of bismuth in order to limit the resistance in accordance with the applied D; C. voltage. The frequency of vibration of the armature is iniiuenced by the inductance and magnetic lag of thecoil as well as by the percentage of chmomagnetic material.

In use the solenoid winding 2| of the vibrator is connected by input conductors 31 and 39 for energization from a source of direct current such as a battery 4|. A high inductive impedance such as a choke coil 43 may be connected in series with one conductor 3l ofthe energizing circuit. If the vibrator is to be utilized as an inverter for convertinga portion of the direct current to an alternating or pulsating current, loutput conductors 45 and 41 are connected from 'opposite ends of the energizing winding 2|, or tapped from intermediate turns.

To restrict the direct current from the output circuit, and for energizing the circuit in accordance with the pulsating component of the energizing current, a condenser 49 is inserted in one output conductor. If the vibrator is to be utilized for supplying only a potential for modulating purposes the condenser may be quite small, but if it is to be utilized to supply a substantial current for power purposes the condenser must be selected of a suitable size. Transformers or other output arrangements may be utilized if desired.

In operation, the current is turned on to energize the coil 2| and to magnetize the core I5. Electromagnetic flux is thus induced to flow through the iield structure of the vibrator passing across the air gap A to the pole I I, thence through the cap 5, through the shell I, and returning from the other end of the shell to the other end of the core by passing through the surrounding air gap B and the adjacent'turns of the coil. The armature is then moved toward the :pole II extending from the cap. This happens because of the tendency of magnetic loops to shorten their length, and because of the peculiar shape of the armature I3 it moves away from the core I9 and toward the pole II to shorten the air gap.

Because of its peculiar non-uniform shape, the movement of the armature toward the pole II decreases the total air gap, as previously described. This decreases the reluctance of the flux path and increases the ux. But increasing flux also increases the density of the eld, to which the coils ofthe energizing Winding are exposed in the air gap, and this in turn increases the ohmic resistance of the Winding, which is of an ohmomagnetic material, as previously set forth. This decreases the energizing current in the Winding and the armature I3 falls back from the pole II toward the core because of the resilience of its support.

Movement of the armature away from the pole II increases the total air gap A and increases the reluctance of the ilux path, as previously set forth. This causes the flux to decrease which diminishes the ileld intensity to which the energizing winding is exposed in the air gap B around the left hand end of the core. The resistance of the Winding 2| is thus decreased and it takes a greater energizing current. The ilux now increases and the armature is again drawn toward the pole II as previously described.

This sequence of operations constitutes a cycle which is repeated periodically with such rapidity that the armature is caused to vibrate. The growing and collapsing of the ileldinduces an alternating current in the energizing winding which may be tapped on by an output circuit as disclosed. Also the winding may be provided with various output taps to provide induced alternating current of any desired potential.

In accordance with another embodiment of our invention, as shown in Fig. 3, two coils I and 53 may be mounted in end-to-end relation for deiining an air gap C between the cores 55 and 51 which are disposed in axial alignment. The right hand coil 5| is wound with ordinary copper wire and the left hand coil 53 is wound with a conductor of bismuth or other ohmomagnetic material. The two coils may be selected in various ratios of resistance, turns, and the like according to the operating characteristics desired and f they are wound and secured upon the cores in the usual manner.

istics for current 'inverter 'use are obtained by providing about ten per cent greater ampere turns on the left hand coil Slthan on the copper coil i. A slack conductor 5t connects adjaacent ends oi the coils 5i and 5t.

The inturned ends ci the cores are respectively square and conically recessed, as in the first embodiment. At its outer end, the right hand' core 5| is integral or joined on the closed end ol a Desirable operating charactercup shaped shell 59 which is provided with a threaded coupling collar Si around its open end. The outer end'oi the left hand core 5l is apertured. to ilrmly receive a pin 63 projecting from a plug of non-magnetic material. I'he outer end of the non-magnetic plug 65 is provided` with a reduced portion 6l which is threaded for se-r. curement in the closed endof a cup shaped shell 69 which has a threaded collar il around its open` edges.

The shells- 59` and 69, which venclose and support their respectivsolenoids, are of any suitable ferroLmagnetic material and they are firmly joined together around' their open edgesl by a .coupling sleeve 'i3 which is internally threaded for clamping the coupling collars. 'I'he sleevel 'i3 is also of ferro-magnetic material and serves to provide (a joint of low magnetic reluctance. The armature 'l 3, similar to that previously described, is supported arounditsjouter edges in an annular recess '15 in the abutting edges of the shells whereby it is disposed in the air gap C between the inner endsol' the cores.` and as in the first embodiment the amature diaphragm has aper-1v tures to minimize damping. lInterconnecting conductor Slis passed through one of the apertures, as shown in Fig. i.

A terminal conductor 11 extends from the outerl end of the ohmomagneticcoil 53 through a suitable bushing i9 in theside wall of,the shell. f

From the outerend oi' thecopper coil 5i, and alsoffrom an intermediate turn, a terminal oo nductor 8l and an intermediate tap 83 are respectively connected passing through suitable insulating bushings In operation the terminal conductor 'il from I the ohmornagnetic coll 53 is connected to a direct current source, such as the batterv tl', as shown in Fie. 5. The intermediate tap 83 fromythe' con per coil di connects to the other side of the hatn To energize an output circuit in accordance with the pulsating con'iponentoi'r the input currenty the terminal conductor iii may be connected through a condenser 8d to an out-put conductor lili. The other output conductor Si is connected from the terminal conductor 'il of. the other coll. This embodiment or our invention operates in a manner substantiallysimilar to the operation described and will not he repeated. l

In the operation' of this embodiment the auton transformer action provides a, higher out-out voltage in proportion tothe input voltage. Also, copper coil ushells may, be provided having different tap connections, resistance, Aand ampere turns for .convenient replacement and attachment to the ohmomagnetic half of the unit.

By eliminating mechanically striking contacts and operating our device in the manner disclosed,

the vibrator is free from mechanical wear, sparking and corrosion which would change its adjustment and shorten its life. j Also disturbing induences are eliminated such .as the noise caused 'of the first embodiment which was previouslyl bythe mechanical striking of contacts and electro-magnetic disturbances caused, by sparking. 'I'he vibratoris free to move with a pure simple harmonic motion, as determined by ,the weight and elasticity of the armature, as Welly as the inductance ol:` the coil and other factors; as previously set forth our contactless vibrator is especially useful asa/radio E supply unit, in luminous sign lighting, as a frequency standard or modu 'lating device and for all purposes where long life and permanent adjustment are important.

lil

-We do not wish to be restricted to the specific Y structural details, of parts or circuits herein set forth, as various modications thereof may7 he.

eiected without departing from the' spirit and scope of our invention.

We claim: y

l. A contatless vibrator comprising, e. deld structure of magnetizahle material deilning an electromagnetic hun path of low `reluctance having an air gap therein, 'an electrical conductor ol ohmomagnetlc material disposed forenergising said field structure and exposure to the hun therefrom, and an armature of magnetizalole material movable for varying said air gap and responsive to the ux therein.

2. A contactiess vibrator comprising, a held structureel magnetiizable material 'having air.

amature ci magnetizable material adjacent the` other air gap for decreasing the tctal'air gap in Aresponse to increasing hun, and a resilient support for movably supporting` said armature.

. d. l contactless vibrator comprising, a held structure ci? ferro-magnetic material having air gaps therein, an electrical conductor oi? llisnfluth disposed adjacent one of said air gaps lor magnetizing the field structure Aand exposure to the hun therefrom, and a magnetizable armature movable adjacent the other air gap.Y ior varying the'total air gap in response to the'varyinayduc `density` therein.

5.. A contactless vibrator comprising, a maislo netizable .structure having an airV gap, the portions ci the field structure on opposite sides ot lsaid air gap being of unlike conformation, an electrical conductor' for magnetizing said held structure, an armature member o Aunlilre conformation on opposite sidesy corresponding to the unlike conformations of the portions of the ileld structure' spaced adjacent said air gap, and resilient means for movahly supporting said arrria-l ture' adjacent the air gap with its unlike conformations toward the held structure surfaces of corresponding conformation.

r `il. Acontactless vibrator comprising, a core oi ferro-magnetic material, a winding of ohmoinagnetic materialA for energizing said core, a shell of ferro-magnetic material enclosing said core,

ya ferro-magnetic cap secured on one end of said y f shell, a ferro-magneticpole extending frein.4 said cap into said shell in spaced relation to derine'an saidcore, and the air gap at the adjacent end of spaced ends of said core and said pole being of unlike conformation, an armature disposed in said air gap, said armature being of unlike conformation on opposite sides corresponding to the unlike conformations of the spaced core and pole dening the air gap, and resilient means for movably supporting the armature in said air gap.

7. A contactless vibrator comprising, a pair of cores of ferro-magnetic material, an enclosing shell of ferro-magnetic material for supporting said cores in spaced end-to-end relation with an air gap therebetween, a winding of copper conductor on one of said cores, a Winding of bismuth on the other one of said cores, an armature movable in response to magnetic ilux from said cores for varying the total air gap, and means for movably supporting said armature adjacent the air gap:

, 8. In combination, a solenoid winding of onmomagnetic material, a source of direct current, a. circuit for energizing said Winding from said source, a eld structure having a flux path magnetized by said Winding, and means for varying the reluctance of said path to subject said Winding to a varying flux for varying the resistance of said Winding in said circuit.

9. A contactless vibrator system comprising, a solenoid winding of ohmomagnetic material, a source of direct current, a circuitAIor energizing said Winding from said source, a iield structure having a ux path magnetized by said winding, i

and an armature responsive to flux in said path for periodically decreasing the reluctance of the path whereby the varying flux varies the resistance of the Winding and the armature vibrates. 10. A current inverter system comprising, a eld structure providing a low reluctance ilux path, a winding of bismuth for magnetizing said iield structure, a source of direct current, an input circuit for energizing said winding from said source, means for periodically varying the reluctance of the ilux path to pulsate the energizing current, an output circuit, andmeans for energizing said output circuit in accordance with the pulsating component of said energizing current.

11, A current inverter system comprising, a eld structure providing a low reluctance ux path, a winding of ohmomagnetic material for magnetizing said field structure, a source of direct current, an input circuit for energizing said winding from said source, an armature responsive to the flux for varying the reluctance of the ilux path, said armature moving to decrease the reluctanceof the ux path in response to increasing flux whereby the armature moves periodically, an output circuit, and means for energizing said output circuit in accordance with the pulsating component of said energizing current.

JAMES L. GREEN. FREDERICK T. mons.

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