US1262838A - Electromagnetic apparatus. - Google Patents

Description

F. P. POOLE.

ELECTROMAGNETIC APPARATUS.

APPLICMION min APR. In. 1917.

1,262,838. Patented Apr. 16,1913.

//1 Ven for. Frede/'fd' P /000/2 N UNITED STATES PATENT oEEIcE.

FREDERICK P. POOLE, OF LA GRANGE, ILLINOIS, ASSIGNOB TO WESTERN ELECTRIC COMPANY, INCORPORATED, F NEW YORK, N. Y., A CORPORATION OF NEW YORK.

ELECTROMAGNETIC APPARATUS.

' Specification of Letters Patent.

Patented Apr. 16, 19178.

Application led April 11, 1917'.v Serial No. 161,188.

Apparatus, of which the following is a full,

clear, concise,and exact description.

This invention relates to electromagnetic apparatus'and has for its object the production of an electromagnetic structure, in which the'energizing winding may be accurately located and positively secured inA definite relation to t'hevendA of its core.

` Generally `stated the invention relates to an electromagnetic structure` in which the energizing coil iswound as a solenoid on a hollow spool, whichspool is adapted to be slipped overa core; the core is provided with a seating 'portion adapted to serve as an abutment or an adjustable spacer interposed between one end of the spool and the said seat.

The invention resides more particularly in providing in an electromagnetic structure, means whereb the energizing winding may be accurate y located and definitely secured on a core and in a predetermined relation to the end thereof wherein variations in the dimensions of the individual parts of the structure may be compensated for at the time the said parts are assembled as a finished product, and whereby continuous production of linished structures having uniform characteristics and of uniform efliciency is assured.

The invention is of particular importance in its relation to telephone receivers where it has been found as the result of an extended investigation including a series of tests that the transmission eiiciency is governed to a considerable extent by the relation between the energizing winding and the end of the core, and that variations in the length of the portion of the core extending beyond the winding will cause variations in the transmission efficiency.

It has also been found upon investigation that transmission efficiency increases as the `length of the core extension beyond the winding is reduced, and that the best results are obtained by locating the winding as near as possible to the end of the core.

A better understanding of the invention.

may be obtained by referring to the drawing forming a part of this application, which shows the invention as employed .in the construction of a, telephone receiver and in which:

Figure 1 is a side view, `in section, of the ma etic structure of a telephone receiver;

. ig'. 2 is a side view of an eleetromagnet of the receiver shown in. Fig. 1;

Fi 3 is an end view of the electromagnet shown in Fig. 2 and illustrates the method used in retaining the winding spool on the core; and

4 is a detailed and side view of a portion ofthe rear end of the electromagn-et of Fig. 2, showing the adjustable spacer introduced between the endof the spool and the seat, or abutment on the pole piece or core. The receiver illustrated in Fig. 1 comprisesamong other things a horseshoe permanent magnet 1, provided with extended pole pieces 2 of reduced cross section, a pair of magnetizin coils 3, an inclosin cup 4 for the pole iece extensions 2 and the coils 3, and a diap ragm 5. The rim of cup 4 is adted to serve as a seat for the periphery of e said diaphragm 5.

The coils 3 are wound on .bobbins consisting of two Bauges 6 and 7, mounted on a tube 8, all composed of s itule insulatin material such as aper, ru b or fiber, an

in the preferred orm of bobbin one end of the tube is extended a short istanee beyond the flange 6. The interna dimensions of tubes 8 are such that the tubes will slide over the ends of the pole iece extensions 2 und make a snug lit. etallic washers 10 are used for the purpose of retaining the .4

coils on the pole extensions and the openings position that the ends of the tubes 8 projectmg beyond the flanges 6 are brought into engagement with the abutments 9, The washers l are then also slipped overl the forward ends of the pole piece extensions and pressed into engagement with the iijn es 7 of the bobbins. Lugs 11, struck out o the bod portions of the washers, pro3ect slightly into the opening through the central portions thereof. These lu grip the sides ot the pole extensions an hold the said washers in lace, which washers, 4in turn, hold the coi 3 in place on the pole extensions.

The complete magnetic structure, except the diaphragm, is then inserted into a suitable machine. and pressure is applied to the Washers 10, and they am forced along the pole extensions until the ends of such extensions extend a, predetermined distance beyond the said washers. The pressure applied to the washers 10, in addition to forcing the Washers along the pole extensions, also forces the bobbins with their fwindings as a whole-alon the said pole extensions but inasmuch es t e tubes of the seid bobbin spool are of a suitable material such as paper, rubber or fiber, the portions oi the said tubes 8 extending beyond the flanges 6 are compressed or crumpled, and as a result permit the coils to move alon the pole extensions -far enough 4to permit the coils to be located at the predetermined position K and at the same time serve the purpose of 3 an adjustable spacer between the flanges 6 of the bobbins 3, and the abutments 9. The extended portions of the tubes 8 in their engegement with abutments 9 also provide a.

i ver with a core, an abutment ineens for holding the bobbins in engagement with the washers 10.

As an alternative method of assembling the coils into the magnetic structure, and in accordance with this invention, the ends of the tubes B may be made iiush with the flanes 6., and separate elements in the shape of t e tubes S and of any suitable material, may be slipped over the pole extensions prior to the placing of the bobbins thereon, and the said separate tube sections will serve as adjustable spaces when the pressure is applied to the washers 10 for the purpose of seating the coils on the pole extensions in their predetermined positions.

What is claimed is:

1. In an electromugnet, the combination of a core, nn abutment. 'on said core, n bobbin adapted to sli over said core, a. retaining washer for said bobbn, and a yielding spacing element between said bobbin and said abutment, whereby said bobbin is held in a position determined by said retaining washer.

2. In an electromagnet, the combination formed on said core, a bobbin adapted to sliliover said core, a. retaining device for said obbin adapted to it over the said core and to engage therewithand a. compressible spacing element on said core between the abutment and one end of said bobbin adapted to permit the bobbin to assume, under pressure, a predetermined position, and to maintain the said bobbin in seid redetermined position.

In witness w ereof, I hereunto subscribe my name this 2nd day of April, A. D. 1917.

FREDERICK P. POOLE.

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