US1661829A - Dynamo-electrical vibrating unit - Google Patents

Description

Patented Mar. 6, 1928.

UNITED STATES PATENT oFFic E.

DYNAMIC-ELECTRICAL VIBBATING UNIT.

Application filed June 4,

This invention relates to a dynamo-electrical vibrating unit for converting electrical pulsations into mechanical movement or vice versa, and its principle objects are to pro vide an instrument which shall:

First. Be highly eflicient, due to the accentuation of the motive force operating upon the reciprocating elements.

Second. Consist of few parts.

'lhird. Have these parts of simple construction so that the instrument shall be easily assembled and easily adjusted.

Fourth. Be economical in cost of production.

Fifth. Be so designed that it shall be readily adaptable to the activation of radio loud speakers and telephone receivers, as well as to electric relays, switches and meters.

' A desirable form of this instrument con sists of a permanent magnet having a general S-shape with like poles at the extremities of the 8 these poles being connected to each other by light vibrating reeds or other members capable of conducting the magnetic flux. One of these reeds is arranged to form the common armature of two coils wound in directioi'is opposed to each other, by which a like polarity is established at the extremities of the arn'iature reed, and the opposite polarity at the center of the reed, these polarities changing as the direction of the current flowing through the coil changes. At the same time, a path for the magnetic flux is providod, paralleling the armature and connecting the extremities of the S-magnet in the same manner as the armature. Thismagnetic path may be established by means of an 3 ther reed similar to the armature reed, or, in the instance of a. telephone receiver, it may consist of a soft iron diaphragm.

The auxiliary reed, or the diaphragm, as the case may be, compared with air, provides a path of small reluctance tor the magnetic flux, thereby making it possible to provide a certain increment to the flux passing through the first reed when the coils are energized, this being in addition to the usual magnetizing eiiect of the coil upon the armature reed. Hence a greater force is brought to act upon the actuating parts than would otherwise be the case, and as a result, in the instance of a telephone receiver, a greater force acts upon the diaphragm, which of course produces stronger tones.

The features of this invention for which 1925. Serial No. 34,830.

Fig. 1' represents a. vertical center cross section online 1--1, Fig. 2;

Fig. 2,a bottom plan, exposing the intenor of the instrument, the casing being shown in section;

Fig. 3, a section similar to Fig. 1 but show ing a modified construction of the instrument.

Referring to the drawing, 20 represents a permanent magnet having substantially the term of theletterS with the poles N and S. A reed 2.1 of soft steel connects the two N poles to each other, and may be attached to. the permanent magnet by screws 24. Placed around the reed 21, which; thereby acts as an armature, are the coils 25' and 25 these being supported by the screws 26 passing: through extended flanges 27 of the spool 28 on which the coils are wound. The screws 26 are fastened in the central branch 20 of the permanentmagnet. Terminals 29 and 30 lead from the coils and are connected to the binding posts 31 and 32 respectively. The permanent magnet may rest upon. the shoulder 34 the latter formingan integral part of the casing 34:. A secondmagnetic reed 41, in the construction shown in Fig. 3, or a diapln-agm42, in the construction shown in Fig. l, in magnetic contact with the permanent magnet. In either instance the reeds may be ,tensioned by means of the screws 43 passing through the walls of the casing. In order to more easily stress the reeds, saw kerfs 45 may becut in the bends of the Smagnet, thereby causing the bodyof the magnet to ofi'er less resistance to the screws 4:3.

In Fig. 1 the reed 21 is connected to the diaphragm 452 by means of the tie 46 passing through a hole 47 in the center branch ofthe permanent magnet. The tie 46 should be made of a non-magnetic substance, such as brass wire, and berigidly fastened to. the

reed 21 as at 48. The diaphragm 42, may be stressed adjustably against the reed 21 by means of the nut 49 threaded on the tie 46.

In the constructionshow-n in Fig. 3, the tie 56 may be secured-to the two reeds 2land 4:1, and the diaphragm 52 be adjustably stressed against the two reeds, by means of there is a greater increase in the the nut 59 threaded on the end of the tie 56.

In the case of a telephone receiver, the ear-piece 60 may be provided, this being threaded on the casing 34. as usual. In the instance of a loud speaker, the cap 70, provided with the usual neck 71 for connecting it to an amplifying horn, may be screwed to the casing 34 in a similar manner.

The operation of the instrument will now be explained in detail with particular reference to Fig. 3. When an electric current passes through the coils 25 and 25 in the proper direction, the magnetic flux through the reed 21 is increased, and naturally strengthens the magnetic pull between the pole S and the central portion of the reed 21. The lowered resistance to the magnetic flux offered by the reed 21, combined with the increased resistance to the passage of the flux in the reed 41, which result from the effect of the current in the coils tending to magnetize the reed 41 oppositely to the reed 21, establish the opposite polarity at the center of the reed 41 from that at the center of the reed 21, and cause the flux which previously passed through the reed 41 to be transferred to the reed 21. Tplus,

ux through the reed 21, than would normally be produced by the magnetizing effect of the coils upon that reed. alone. This magnetic condition results in the movement of the reed 21 toward the pole S, and of the reed 41 away from this pole. As the reed 21 approaches the pole S, the reluctance of this magnetic path is lowered, and as the reed 41 moves away from this pole, the reluctance of the path through this reed is increased because of the widening of the magnetic gap. This results in a still greater transfer of magnetic flux from the reed 41 to the reed 21, hence the force tending to move the reeds and the diaphragm, tends also to increase in a greater degree than is ordinarily the case, and thus more nearly approaches the ratio of increase of the resisting forces in the reeds and diaphragm caused by the tension and other stresses within these elements. I

Since movement of the diaphragm can occur only while the motive force acting thereupon is greater than the sum of the internal resisting forces, and since it is evident that this condition would prevail over a, greater amplitude of movement of the magnetic elements in this invention than would be the case without the reed 41, it follows that greater efiicieney in the transformation'o'f electrical energy into sound waves is obtained by theuse of this invention. Also, the movement of the diaphragm is more nearly proportional to differences in the current input, which obviously results in a more natural sound reproduction.

When the current in the coils decreases or reverses in direction, it will decrease the magnetic conductivity of the path through them, and increase the conductivity of the path through the reed 41. Thus, the flux will transfer from the reed 2.1 to the reed 41, causing the latter to be attracted to the pole S, and making it easier for the reed 21 to move away from this pole. This action results in a greatly increased force towards the reed 21, and produces a maximum amplitude of movement of the diaphragm.

'lhe reed 41 and the diaphragm 42 may be regarded as auxiliary armatures with relation to the armature reed 21.

For the reasons stated, this unit gives superior results as an induction type microphone.

A sound wave striking the diaphragm causes the downward travel of the movable elements, widening the gap between S and the central part of the reed 21, thus weakening the flux through the coils and inducing current in them in the usual manner. At the same time, the gap between S and the reed 41 is lessened, thereby making that passage easier, so the flux which previously passed through the reed 21 will be trans ferred to reed 41, resulting in a greater drop in the flux passing through the coils than would ordinarily occur, thus inducing a greater E. M. F. in them. When the movement of the diaphragm is upward, the lessening oi the gap between S and the reed 21 would ordinarily cause an increase of the magnetic flux through the coil. At the same time, however, the gap between S and the reed 41 will be increased, accordingly increasing the reluctance of this path to the magnetic flux and causing the latter to be transferred to the reed 21, thus also causing a greater increase of flux through the Coil, and consequently a. higher E. M. F. to be induced therethrough in the opposite direction.

The actions just described, in connection with the construction shown in Fig. 3, also hold good for the construction shown in Fig. 1, the reed 41 being replaced by the diaphragm 42. When an iron diaphragm is used, the construction in Fig. 1 permits a reduction in the number of parts, but where a dia 'ihragm of mica or other non-magnetic material is used, it will be necessary to use the construction in Fig. 3.

Briefly stated, the novel features of this invention consists in providing two alternating paths or circuits for conducting magnetic flux. Each circuit comprises a permanent magnet and an armature, the magnet being common to both circuits. The a l'lfllltlil'Qr are arranged in spaced relation to each other and connected to maintain this relation. lietween' the magnet and one point of each armature, is an air gap, in each instance forming part of the magnetic circuit. Nor- IOU mally, the two air gaps are'equal to each other, but as the two armatures are compelled to move in unison, when one armature moves towards the magnet a certain distance, the other armature moves away from the magnet an equal distance, and vice versa Thus when one gap is increased, the other gap is decreased, obviously resulting in a transfer of magnetic flux from the path of high reluctance through the wider gap, to the path of lower reluctance through the narrower gap.

One or more coils are arranged to influence the armatures, so that when an electric current is sent through the coils, the magnetic conductivity of one circuit will be decreased and that of the other path increased, and the flux therefore be largely transferred from the latter path, resulting in a force tending to move the corresponding armature towards the magnet and the other armature away from it. When this movement occurs, the resultant lessening of the gap in this path and'the simultaneous increase of the gap in the other path, brin s about a still greater transfer of magnetic flux from this other path to the one in which the gap is lessening, with a resulting increase in the force tending to produce motion.

1f the armatures are moved mechanically, the simultaneous increasing of one gap and the decreasing of the other gap, results in a transfer of magnetic flux from one armature to the other, causing an unusually large change in the magnetic flux through the coil or coils, as the case may be, consequently inducing an increased E. M. F in them.

B providing alternate paths into which the magnetic flux can be diverted,because of the accelerating or retarding effect of the coil magnetism, or, in other words, by producing a commutation of the linx through alternate magnetic paths, rather than by boosting the flux or choking it, in a single path, with no alternate path excepting through a non magnetic medium such as air, the force tend ing to produce motion is greatly increased.

While a specific embodiment of this invention is herein shown and described, all the detailed parts may, or may not be in the preferred forms, and further, the preferred forms may be varied from time to time as the development of the invention and the arts to which it appertains, progress. Therefore, that which forms an essential part of this invention will be discernible from the claims in which its spirit is generalized.

Having fully described my invention, what I claim is:

1. A dynamo-electric vibrating unit having a magnet, two complete and separate magnetic paths across the poles of the magnet, and means for shifting a portion of the magnetic flux from one path so that the said portion shall completely traverse the other path, or vice versa.

2. A dynamo-electric vibratingunit hav-- ing two magnetic paths, an armature in each path across the poles ofa magnet, and an electromagnetic coil arranged to effect an increase in the magnetization of one armature and a simultaneous decrease in the magnetization of the other armature, or vice versa.

A dynamo-electric vibrating unit hav ing two magnetic circuits, a source of magnetism common to both circuits, an armature in each circuit, and an induction coil arranged to oppositely affect the flow of magnetism in the said armatures, relatively to each other, thus causing a portion of the magnetic flux to shift from one armature to the other arn'iature, or vice versa.

t. A dynamo-electric vibrating unit having two magnetic paths, a magnet common to both paths, and. electromagnet coils wound in directions opposed to each other, arranged to exert a shifting effect upon one path to cause the transfer of a part of its magnetic flux to the other path, or vice versa. 7 5. In a dynamo-electric vibrating unit, the

combination with a magnet having an 8 form, of an armature reed connecting the extremities of the said magnet to each other, coils wound in directions opposed to each other arranged to act upon said armature, and an auxiliary magnetic member substantially paralleling the said armature and also connecting the extremitiesof the said magnet to each other.

(5. In a dynamo-electric vibrating unit, a.

magnet having an 8 form, magnetic reeds spaced apart from and substantially pa alleling each other, extending from one extremity to the other of the said magnet and in magnetic contact therewith, coils wound in directions opposed to each other, and arranged to directly influence one of the said reeds and to exert a secondary effect on the other reed, a diaphragm arranged in operative proximity to the said reeds, and

a tie extending from the saidreeds to the diaphragm. I

7. In a dynamo-electric vibrating unit, a permanent magnet having a central branch, side branches extending outwardly from the central branch in directions opposed to each other, magnetic reeds substantially paralleling each other and joined to the extremities of the said side branches, electromagnetic coils Wound in directions opposed to each other, placed in operative relation to the said reeds, means for tensioning the said reeds, a diaphragm arranged in proximity to the reeds, and a tie connecting the reeds to the diaphragm.

SQA dynamo-electric vibrating unit com prising a magnet, a plurality of separate magnetic paths across the poles of the magnet, and means for increasing the total magnetic resistance of certain of said paths while simultaneously decreasing the resistance of certain other of said paths, thus causing a portion of said flux to shift from certain said paths to certain other said paths, or vice versa.

9. A dynamo-electric vibrating unit having a magnet, a plurality of separate, variable magnetic paths across the poles of the magnet including a movable magnetic member, and an electronnlgnct arranged to cause a shifting of a portion of the magnetic flux from certain of said paths so that the flux shall completely traverse certain other of the said paths andthus exert a force on said magnetic member opposite to the force previously exerted thereon by said flux, or vice versa.

10. A source of magnetism, a plurality of movable armatnres associated therewith, each armature being arranged to complete a circuit carrying a separate fractioi'i oi the total magnetic flux, and means for rausing the complete removal of a portion of the magnetic flux from certain of said armatures and a simultaneous addition of this same portion of flux to certain other of said armatures, or vice versa.

11. A permanent magnet, an :n'mature reed extending from one polarity to the other polarity of the said magnet, a second armature reed extending similarly from polarity to polarity but located on that side of the said magnet opposite to the lirst reed, corresponding portions of each reed being iixed to one and the same polarity of the said magnet, while other portions oi the said reeds are rigidly connected to each other, but are spaced apart from the said other polarity, and means directly operative upon one of the said reeds for moving that reed relatively to the said other polarity, thereby varying the gaps between the respective reeds and the said other polarity in inverse proportion to each other.

12. A permanent magnet, an arn'lature reed extending from one polarity to the other polarity of the said magnet, a second armature reed extending similarily from polarity to polarity but located on that side of the said magnet opposite to the first reed, corresponding portions of each reed being lixed to one and the same polarity of the said magnet, While other portions of the said reeds are rigidly connected to each other, but are spaced apart from the said other polarity, and an electromagnet directly operative upon one of the said reeds for moving that rced relatively to the said other polarity, thereby varying the gaps between the respective reeds and the said other polarity in inverse proportion to each other.

13. A dynamo-electric 'ibrating unit having a magnet, a plurality of separate alternative magnetic paths for conductance of flux across the poles of the magnet, a movable magnetic member in each path and an electromagnetic coil arranged so that a variation of current in said coil will simultaneously cause an increase in the total reluctance of certain of said paths, and a corresponding decrease in the reluctance of certain other of said paths, or vice versa.

it. A dynamo-elmztric vibrating unit comprising a magnet, a plurality of separate armatures associated with said magnet, said armatures being arrmigcd so that a variable air-gap exists between a certain pole of said magnet and each of said armaturcs, and means for simultaneously causing an increase in certain of said air-gaps and a corresponding decrease in certain others of said air-gaps, or vice versa.

15. A dymuno-electric vibrating unit having a single magnet with two armaturcs, said armatures being so ititer-connected that they must move in unison with each other, the parts being so arranged that when movement of said armatures occurs, the permeability of the path through one of said armatures, will be increased while the permeability of the path through the other armatures will be decreased, or vice versa.

In testimony whereof, I sign my name hereto.

THOMAS ll. Ill )WELLS.

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