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Publication numberUS222118 A
Publication typeGrant
Publication dateDec 2, 1879
Filing dateAug 18, 1879
Publication numberUS 222118 A, US 222118A, US-A-222118, US222118 A, US222118A
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Improvement in magnet-telephones
US 222118 A
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Description  (OCR text may contain errors)

2 Sheets-Sheet 1 G. ADER. Magnet Telephones.

Patented Dec. 2, I879.


2 Sheets-Sheet 2.

OJADER. Magnet Telephones.

No. 222,118. Patented. Deb. 2, 1879.,

e .KIQ MHW F v 5:1 m m I Z 2 .g e e, e e I m \\m\ x N PETERS, E


Specification forming part of Letters Patent No. 222,118., dated December 2, 1879; application filed August 18, 1879. i

telephones requiring the aid of abattery for operation. In this class of telephones the transmission and reproduction of speech depend upon the vibrations .of an inductive armature in frontof agnetic poles surrounded by bobbins, the vibrations of the armature inducing or responding to currents in the coils of the bobbins.

In the telephones now known and usedthe magnetic poles are separated by a distance in general somewhat greater than the diameter of the coils, and are paralle1,or nearly so, their ends facing the armature. A telephone has, however, been devised in which an electro-mag-net with its poles beyond the ends of the bob-bins bent at right angles, so that they face each other, is used in connection with an ordinary metallicvibratory-plate. In thiscase the bobbins are parallel, as usual.

This invent-ion is essentially different from the above 3 and it consists in bringing the poles of the electro-magnet together almost to the pointof touching, to create thereby a magnetic plane, opposite the center of which is suspended from a suitable vibratory plate or diaphragm an inductive armature, exceeding but slightly, if any, .the distance between the poles. By brin gin g the poles thus together the attraction upon the armature -1s concentrated, and, the latter being of light weight, the read iness and amplitude of its vibrations are increased. In this invention, -moreover, the

bobbins which surround the magnetic poles are arranged end to end, as well as the latter.

In order 'to carry out most effectually the principles above indicated, I employ, by preference, the following disposition: Two magnets of the ordinary horseshoe form are placed parallel with each other, being separated from each other throughout their length. Between the ends nets are placed pole-pieces of soft iron, the ends of which face each other, and, being brought very close together, are united by a small insulating or non-magnetic strip of suitable material, such as brass. Thepole-pieces are in the form of flat oblong or rectangular strips, and are each surrounded by coils of inteleof the two magsulated wire, through which coils the phone-circuit is completed,

The inductive armature is but slightly wider and longer than the non-magnetic strip. It is attached to the diaphragm of the telephone, and is disposed symmetrically over the said strip, so as to be suspended above, to extend a slight distance over the magnetic poles.

The diaphragm may be of almost any kind of material. It may, for example, be a thin plate of wood, free or secured at the sides; or 4 f it may be a thin sheet of metal, which can be stretched as desired; or, again, it may he of mica. In a word, any plate susceptible of vibration and adapted to transmit sound may be .used.

The diaphragm may be square, round, oval, or an ydesired shape. It m a r be exposedorcm ered with a protecting-plate provided with a mouthpiece or acoustic tube.

The accompanying drawings, which form a part of this specification, represent telephones constructed in accordance with my invention, Figure 1 being an elevation with the diaphragm removed; Figs. 2 and 3, horizontal and vertical sections, respectively, on line a: a0 and y y, Fig. 1 Fig. 4, acentral vertical section of a'moditied construction Fig. 5, a section on line 2 z,

armature differently connected with the diaphragm from that illustrated in the other figures.

The same letters refer to like parts on the drawings wherever they occur.

' A represents two horseshoe-magnets B B, the two'pole-pieces, of soft iron, fixed between the two pairs of poles of the magnets. The two pole-pi eces are brought very close together, an d Fig. 4; and Figs. 6 and 7, partial views in different planes, showing the separated by a strip, a, of nonmagnetic material-copper, for instance. 0 G are bobbins carried by the pole-pieces, the coils of which are connected With bindingposts, as shown in Figs. 1, 2, and 3, or otherwise connected in the telephonic circuit.

, The parts above described are inclosed in a box, X, of wood, ebonite, or other material, upon the face of which thevibratory diaphragm G is secured. This diaphragm is very large, and to it is attached the armature b by means of a block or tongue, D, fixed solidly to the center of the diaphragm. The armature is but little larger than the insulating material, and is held at a very small distance from and projects at the sides over the pole-pieces or cores B B. The armature is thus placed opposite the center of the magnetic plane created by the polesof the magnet.

The adjustment is effected by any suitable meansfor example, by springs and set-screws, as shown, operating to raise and lower the magnet.

The diaphragm, as before stated, can be of wood, mica, &c., and of all forms, free or stretched. In the drawings the diaphragins represented are square or rectangular, with a width exceeding somewhat their length. 111 Figs. 1, 2, and 3 the diaphragm is shown exposed, while in Figs. at and 5 it is covered with a plate provided with a mouth-piece.

In Figs. 4 and 5 the telephone is shown provided with devices for stretching the diaphragm.

The piece D for securing the armature to the diaphragm may be of different shapes and sizes, as illustrated in the different figures. As shown in Fig. 2,

it corresponds in width with the armature. It may extend the entire length of the diaphragm, or be of the same length as the armature, or somewhat less. In Figs. 4. and 5 it is shown extending nearly the length of the diaphragm, and rounded on the under side, the armature being centrally attached, while in width it is very much less than the armature, and is placed in the middle line of the latter. In Figs. 6 and 7 the piece D is thin and shorter than the armature. The material of which the piece Dis composed may be the same as that of the diaphragm, as wood, or it may be metal.

2 I Q22dll Although I have shown the magnet composed of two magnets of horseshoe form, separated from each other, yet one, or three, or more may be used, and I do not limit myself to the horseshoe form.

The pole-pieces may be fixed in position on the permanent magnets in any way deemed proper, so long as they are under the magnetic influence.

The box or case may be of any suitable form and dimensions.

Having thus fully described my said invention, and the manner in which the same is or may be carried into effect, what I claim, and desire to secure by Letters Patent, is-

1. A telephone having the poles of the mag net brought together almost to the point of touching, as described, thereby creating a magnetic plane, and provided with an inductive armature of a width but slightly, if any, greater than the space between the poles, arranged opposite the center of the aforesaid magnetic plane, whereby the readiness of the diaphragm of the telephone to vibrate and the amplitude of the vibrations are increased, substantially as set forth.

2. In a telephone, a magnet with pole-pieces connected with opposite poles, and arranged with their ends facing each other and brought almost to the point of touching, the said polepieces being surrounded by bobbins, the ends of which latter face each other also, substantially as describec 3. The combination, with a magnet having its poles surrounded by bobbins, brought together end to end almost to the point of touching, and separated by a strip of non-magnetic material, the said bobbins being placed also end to end, of an armature but slightly wider than the non-magnetic strip, suspended from a vibratory diaphragm between the ends of the said bobbin centrally over the aforesaid strip, substantially as described.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.



FREDERIG A. GowER, R0131. M. Hoorna.

Cooperative ClassificationH04R11/00