US695539A - Electromagnetic apparatus. - Google Patents

Description

No. 695,539. Patented Mar.. I8, |902.

` F. B. 000K.

i* ELECTROMAGNETIC APPARATUS.

(Application led Aug. 29, 1899.)

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UNITED STATES FRANK B. COOK, OF

PATENT OFFICE.

CHCAGO, ILLINOIS.

ELECTROMAGNETIC APPARATUS.

SPECIFECATION forming part Of Letters Patent NO. 695,539, dated March 18, 1902. Application filed August 29, 1899. Serial No. 728,820. (No model.)

To @ZZ whom it may con/cern:

Be it known that l, FRANK B. COOK, a citizen of the United States of America, and a resident of Chicago, Cook county, Illinois, have invented a certain new and useful Improvement in Electromagnetic Apparatus, of which the following is a specification.

My invention relates to certain improvements in an electromagnetic apparatus which is especially adapted, although not exclusively, for 'use in connection with telephone apparatus, and I shall therefore describe and illustrate my invention in connection with such apparatus.

In the central oflice ot a telephone system a switchboard is provided at and by which operators establish connection between the various circuits of the subscribers as and when called 'upon by any subscriber desiring to be coupled for conversation with some other subscriber. ln order to attract the attention of the operator at the switchboard to the circuit of any given subscriber, annunciators or visual indicators are provided, one for each subscribers circuit, which are operated to display or give a signal by a current generated at the subscribers station extending the call, which current acting upon an electromagnet of the annunciator operates it to display the signal. lt is desirable that the annunciator or drop be capable of sensitive' and invariable operation by currents of minimum strength, as the conditions which prevail in telephonie systems tend to impair and reduce the strength ci' the currents in generation and when generated.

The object of my invention is to provide an electromagnetic apparatus which shall be ca pable of sensitive action to invariably operate the annunciator by currents of a much less strength than has been possible heretotore.

My invention has certain other objects in view; audit consists in certain features,which will be fully described, and pointed out in my claims, reference being now had to the accompanying drawings, in which- Figure l is a side elevation of my improved annunciator. Fig. 2 is a central longitudinal section. Fig. 3 is an enlarged central longitudinal section of the central portion of the annunciator, showing the armature-lever and armature away from the magnet-poles in a position to be attracted thereby. Fig. 4 is an exterior View of said central portion of the annunciator, also enlarged. Fig. 5 is a crosssection on the line a a of Fig. 2. Fig. 6 is a like view on the line b h of Fig. 2. Fig. 7 is an exterior view of a modified form. Fig. 8 is a central longitudinal section of the same.

My invention broadly consists in an electromagnetic apparatus comprising substantially in construction an inclosing magnetic shell surrounding the electromagnet and formed in two parts, together with an armature acted upon by the magnetic poles ot' said shell, whereby the poles of the magnetic shell 'are presented in such close proximity to the armature as to obtain the maximum pull with a minimum current.

My invention also consists in disposing the armature in such relation to the pole or poles of the electromagnet that said armature is permitted to have a greater range of movement and yet remain always within the field ot force of the magnet, whereby the armature is invariably operated and permitted and given a wider or greater range of movement, and this is accomplished by an operating-current of less strength.

l shall proceed to describe my improvements in connection with the anuunciator of a telephone-exchange.

In annunciators as now usually constructed the one end of one pole of the electromagnet acts upon a pivoted armature, which in turn operates a pivoted latching-lever engaging a pivoted shutter, whereby the armature when attracted by one end or one pole of the magnet operates the lever to release the shutter, which then drops or falls and in so doing indicates or gives the signal to the operator.

The electromagnet Ais disposed within the tubular magnetic shell B,which latter is made in two parts B2 and B3, each secured to the end of the core A2 of the electromagnet by the screws A3 and Ai. The armature D is ring-shaped, surrounds the electromagnet A and its shell B, and is pivoted approximately at the center D2 to diamagnetic pivot-pieces d d; the pivot -screws c c, Fig. 5, passing through diamagnetic pieces ff on the arman IOC) Vzo

ture and entering said pivot-pieces. By this means the armature is magnetically insulated from the magnetic shell B and virtually made up of two parts or pieces isolated from each other. The pivot-pieces d d are held by the diamagnetic shield g. Angular-shaped polepieces J and J2 are secured on or formed, respectively, with the parts B2 and B3 of the shell B on the upper and lower sides thereof, and the poles of the magnet are therefore located, respectively, above and below the pivot D2 of the armature D and presented to opposite sides and vertical ends of said armature. The end portion of each of the parts B2 and -Bs of the magnetic shell in proximity to the armature D are cut away, as shown more clearly by the dotted lines of Fig. 3, to form the pole-pieces K and K2, which are thus beneath or within the ring-armature D. By reason of the weight of the latch-lever E the armature D tends to remain in a vertical position away from the pole pieces J J2, as shown in Fig. 3. It will be observed, however, that when in this position the armature is at the same distance from the pole-pieces K and K2, and therefore these poles exert aY pull immediately upon the armature D, theV poles J and J2 also supplementing and increasing this pull. YThe armature always maintains thesame slight'relative distance from the pole-pieces K and K2 in all its kassumed positions and notwithstanding the armature is given a wide range of movement it is always immersed within the magnetic field of the pole-pieces K K2. The armature as ordinarily used at present is pivoted at its upper or lower end in proximity to the magnet, and therefore a part of the energy of the magnet is wasted in exerting a pull upon the stationary pivot-point of the armature. Also the outer end portion of the armature in such a construction is relatively distant or remotel from the pole of the magnet and cannot be given a wide range of movement, as it would then be brought without the field of force of the magnet.

In my construction as shown in connection with the annunciator the armature is preferably centrally pivoted and a pole presented above and below said pivot and on either side of the armature, certain 'of the pole-pieces being arranged in suchrelation to the armature that it always remains at the same distance from said pole-pieces, and therefore always immersed in the eld of fo'rce thereof to be immediately acted upon thereby, the other pole-pieces supplementing'and exerting an additional pulling force. The pole-pieces unitedly exert an inuence which causes the armature to rotate on its pivot into the position shown in Figs. l and 3, thereby lifting thelever E to release the shutter H.

It will also be observed that I Aobtain a greater leverage in acting upon the armature, because the pole-pieces below the pivot exert a pull upon the lower lever-arm of the larmature in one direction, and the pole pieces above said pivot exert a pull upon the upper lever-arm of said armature in an opposite direction, the combined iniluence of the two sets of pole-pieces resulting in the rotation of the armature on its pivot and the lifting of the latching-lever.

In Figs. 7 and 8 I have shown a form in'` which the pole-pieces J and J2 are not employed, in whichk case it is not necessary to divide the armature into two parts by the diamagnetic pieces f f, as is done with the form previously described. It will be particularly observed that by reason of this construction the armature is always in close proximity to the electromagnet-poles, and thereby a maximum pull is brought to bear upon the armature by the poles with a minimum current. Again, as the electromagnet is surrounded by a heavy metallic shell, should the coil burn out under excess of current the shell would protect the other portions of the apparatus from injury by fire.

Having thus described my invention, what I claim as new therein, and desire to secure by Letters Patent, is-

1. In an electromagnetic apparatus, a twopart armature approximately centrally piv.

oted, an electromagnet and a plurality of polepieces of said magnet arranged on eitherside of said armature and above and below the pivot thereof, a latching-lever anda drop or` shutter normally held by said lever.

2. In an electromagnetic apparatus, a twoon an axis located between the poles of said two-part shell.

4. In an electromagnetic apparatus, a twopart magnetic shell, an electromagnet connected therewith, and an armature centrally pivoted and positioned between the' poles vof the shell.

5. In an electric magnetic apparatus, a twopart magnetic shell, an electromagnet connected therewith and a centrally-pivoted'ringy shaped armature positioned between the poles of the shell and surrounding the electromagnet.

'6. In an electromagnetic apparatus, a twopart magnetic shell, an electromagnet connected therewith and a centrally-pivoted ringshaped armature which surrounds the electromagnet and the pole-pieces of the shell whereby said armature remains within the field of force of said pole-pieces.

7. In an electromagnetic apparatus, anlag- IOO IIO

netic shell formed in two parts each of which is connected with the electromaguet and each having a. pole-piece and a two-pmt armature together Withsupplemental pole-pieces on the ends of the magnetic shell.

S. In an electromagnetic apparatus, a tWopart magnetic shell, an electromagnet connected therewith and L ring-shaped armature, suitably pivoted encircling said electromagnet and positioned between the poles of the 1o shell.

Signed by lne at Chicago, Cook county, Illinois, this 26th day of August, 1899.

FRANK B.. COOK.

lVitnesses:

CHAs. C. BULKLEY, L. W. BULKLEY.

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