US1333247A - Electromagnet - Google Patents

Description

, is ineffective.

GEORGE C. CUMMINGS, OF EAST ORANGE, .NE-W JERSEY.

ELECTROMAGNET.

Specication of Letters Patent.

Patented Mar. 9, 1920.

Application ,led May 1, 1919. Serial No. 294,117.

To all whom it may Concern.'

Be it known that I, GEORGE C. CUMMINGS, subject of King George of England, residing at East Orange, in the county of Essex and State of New Jersey, have invented a certain new and useful Improvement in Electromagnets, of which the followingV is a full, clear, concise, and exact description.

My invention, in one aspect, relatesto electromagnets included in the class that embraces the polarized relay disclosed in the expired patent to Anderson, 267,966, of November'21, 1882.

The invention also relates to a novel armature mounting 4 which is preferably employed in the vmagnet having the other characteristics of my invention.

The invention has for one of its objects the elimination of residual magnetism in the oscillating relay or magnet armature that is arranged along a face of a polar end of the magnet. In carrying out my invention this polar face is of a length that is a multiple of twice the width of the space between the axis of the armature and said Vpolar face. This armature is threaded transversely ofits length by the flux of a magnet,

preferably a permanent magnet, substantially throughout all of the armature that is opposite said .polar face. The armature is operable by means of an energizing circuit that includes a winding arranged, when the circuit is effective, to set up flux in said armature longitudinally thereof, the transverse flux of the aforesaid permanent magnet being of strength effective to eliminate longitudinal flux or residual magnetism in said armature when said energizing circuit In' the preferred embodiment of the invention thev magnet that establishes the transverse fluir' has closely approached polar ends whose opposing faces are substantially parallel throughout a length that is a multiple of the width of the space between said parallel faces.

In magnets of the prior art the interpolar spaces were very wide and short. The flux produced by the permanent magnts'of the prior art would not be permitted to exceed the most favorable magnetization points to prevent the magnets from becoming insensitive, a result that would follow excessive iluX due to increased pressure of the Varmavoperating flux before effecting armature movement. The limitations heretofore present in the design of such magnets or relays have made it impossible to produce structures in which the permanent magnets would eliminate the residual magnetism, owing to the fact that only small portions of the armature lengths were subject to the transverse fiuXof the permanent magnets. When there is residual magnetism in the armature a force substantially equal thereto must be dded to the forceexerted by the operating In accordance with the remaining feature of my invention the armature is mounted upon a bar spring with which the armature is in rigid connection. This bar spring is preferably a strip metal spring secured at its ends to a suitable support.y By means of such an armature mounting the armature may be held in mid position without engagement with either front or back contact.

I will explain my invention more fully by reference to the accompanying `drawing showing the preferred embodiment thereof and in which Figure 1 is a view, somewhat diagrammatic, illustrating the preferred structure of my invention; Fig. 2 vis a perspective view of a structure embracing the invention, parts being indicated in section; and Fig. 3 is a perspective view illustrating the preferred armature mounting.

Like parts are indicated by similar characters of reference throughout the different figures.

The magnet which I employ for effecting the transverse flux is desirably permanent and is preferably made up of a number of horseshoe magnet elements lhaving closely approached polar ends 2 and 3. The polar ends 2 of the magnet elements 1 are upon one side of the interpolar gap and the polar v stops.

ends 3 of the magnet elements l are upon the other 'side of the interpolar gap. The opposing faces of the polar ends of the com-- pound magnetV are substantially parallel throughout a length that is a multiple of the width of the space between said parallel faces. An oscillating armature 4 is located in and is disposed longitudinally of vsaid space and is threaded transversely of its length by the -flux ofthe permanent magnet y substantially'throughout all of the armature that is in said space, An energizing circuit is provided for` the armature and includes a winding 5V arranged, when the circuit is effective, to set up flux in the armature longitudinally thereof, the transverse flux of f the compound magnet being of strength effective to eliminate longitudinal fluX or residual magnetism in said armature whensaid energizing circuit is ineffective. The mounting for the swinging armature/is desirably inthe form of a bar spring 6 which is preferably a strip metal spring permitting slight axial movement of the armature. This slight axial movement is the reciprocatinglengthwise movement of the armature at the contact points where the structure'is used for a relay. The armature is brought into rigid relation with said spring where connected therewith by means of a pin 7 i rigidly secured to the armature and spring. The armature supporting spring is itself supported at its ends upon the nonmagnetic support 8. The pin 7 is a strain equalizing pin that serves to distribute' the torque of the spring evenly across the face of such spring which may be so arranged that its force is always such as to maintain or tend to maintain the armature in the center of the space between the contact 'screws or stops 9 and 10.- Such spring force is adjusted so as nearly to but not quite offset the force, due to the permanent magnet flux,

that tends to hold the armature against said The armature is positioned to be subject to the actuating influence of the flux 'on both sides of the spring.

It will be observed that each polar end face of the permanent magnet is of a length that is a multiple of twice the width of the space between the axis of the armature and said face and while I prefer to employ two closely approached polar ends, I do not wish to be limited to this arrangement. It is preferable to make the width between the pole faces commensurate with the height of each individual one of the several permanent magnets comprising the structure because thereby the reluctance of the air gap between the faces insures a considerable percentage of the iux established by the permanent magnet passing directly across this `gap rather than taking the longer and greater reluctance path out to the added tween the pole faces at all points. The two' together insure that the transverse flux shall be effective to eliminate residual magnetism.

In a very effective arrangement the distance between t-he poles is not more than onesixth of the length of each polar'face, such length being measured along the armature,

and the strength of the permanent magnet should be ten or fifteen times that which is ordinarily present in a relay structure of the aforesaid Anderson type. By the arrangement herein disclosed an intense substantially equally distributed transverse field is established, neglecting reference to the leakage -and fringe effects over the faces of the poles.

The armature 4 may be of soft iron, if desired, and preferably has a non-magnetic continuation 11 to carry contacts 12-and 13 when the structure is employed as a relay. The intense transverse magnetic field due to the combined permanent magnet effects the arrangement of the molecules of the armature in alinement with each other in the transverse directions followed by the permanent magnet flux whereby one long face of thearniature is caused to be of one polarity and the face of the armature parallel to the aforesaid armature face is caused to be of the opposite polarity.

The operating circuit of the magnet is inclusive of a winding 5 which is preferably subdivided into two coils arranged on opposite sides of the armature mounting spring 6. Any suitable form of circuit controlling switch is employed, a circuit closing switch tion. This iux will cause the movement of the armature in one direction or the other depending upon the polarity of the battery and the direction of the winding 5. When the key 14 is released so as tobe in open position ther molecules of the armature which were disturbed by the longitudinal flux will assume their former positions transverse of the armature and parallel with the transverse flux of the permanent magnet which is at right angles to the length of the armature, such a shifting of the disturbed molecules to normal position being due to the intensity of the transverse flux ofthe permanent magnet. All longitudinal flux, or residual magnetism, in the armature is thus eifaced when the operating circuit of the ma net is opened.

n thepreferred embodiment of the invention illustrated in Fig. 2 there are em-l ployed miniature polar extensions 16 that serve merely to concentrate locally very small portions of thev transverse permanent magnet flux adjacent the ends of the armature to correspond with the concentration of the operating flux at thearmature extremities. i

In the structure of the Anderson type the forces which tend to move the armature and that result from the operating current fluxv are those exerted within the limitations of the polar extensions adjacent the extremities 'of the; armature.` In my structure the forces tending to move the armature are not only existent within Ithe limits of the polar extensions 16- but are'strongly existent over the maj or portion of the length of the armature because of the tendency of the transverse permanent magnet field that suppliesr a field of flux overthe entire length of the armature to enable 'the lweaker operating flux to become effective to move the armature, this weaker operating flux being effec? tive throughout the major portion of the armature length` as well as at the armature extremities.

While I have herein shown and particu'- larly described the preferred embodiment of v my invention I do not wish to be limited to the precise details of construction shown as 'changes may readily be made without departing from the spirit of my invention, but having thus described my invention I claim as new and desire to secure by Letters Pat- 1. A magnet structure including a permanent magnet having closely approached polar ends whose;4 opposing faces are sub' stantially parallel throughout`a length that f is a multiple of the width of the space be-- tween said parallel faces; an oscillating i armature inv and disposedlongitudinally of said space and threaded transversely of its length by the flux of the permanent magnet substantially throughout all of the armature that is in said space; and an energizing cirrcuit for said armature including a winding arranged, when the circuit is eective, to set up iux in saidv armature longitudinally thereof, the transverse Hux ofthe permanent magnet being of strength e`ective to eliminate longitudinal flux or residual magnetism in said armature when said energiz-y ing circuitis ineffective. .A

2. A. magnet structure including a magnet having closely 'approached` polar ends whose opposing faces are substantially parallel throughout .a length that is a multiple of the widthAv of the space between `said I parallel faces; an oscillating armature in and disposed longitudinally of said space and threaded transversely of its length by the flux of the magnet substantially throughout all of Ythe armature that. is in said space; and an energizing circuit for said armature including a winding arranged, when the circuit is effective, to set up flux in said armature lon itudinally thereof, the transverse flux of tIie magnet being of strength effective to eliminate longitudinal flux or residual ma etism in said armature when said energizing circuit is ineffective.

3. Amagnet structure including a permanent magnet; an oscillating armature arranged along a face'of a polar end of said magnet, which face is of a length that isl a multiple of twice the width of the space between the axis of the armature and said face, said armature being threaded-transversely of its length by the flux of the permanent magnet substantially throughout all of the armature that is'l opposite said -polar face; and an energizing circuit for said armature including a winding arranged, when the' circuit is effective to set up flux in said armature longitudina ly thereof, the transverse flux of the permanent magnet being of strength effective to eliminate longi tudinal flux or residual magnetism in'said armature when said energizing circuit is in effective.

4. A ma net structure including a-.Imagnet; an oscillating armature arranged along.

twice the width of the space between the axis of the armature and saidface, said armature being threaded transversely of its length by the flux of the magnet substantially throughout all of the armature that is opposite said polar face; and an energizing circuit for said armature including a winding arranged, when the circuit/is effective, to set upflux in said armature longitudinall thereof, `the transverse flux of the magnet eing of strength effective to eliminate longitudinal flux4 or residual magnetism in said armature when said energizing circuit is inefective. p

5. An electro-magnet including a magnet winding; a swinging armature movable by the flux due to said winding; a bar spring extending transversely of the armature and upon an intermediate portion of which the armature is mounted at an intermediate portion of the armature where the armature is in rigid connection with the spring, the armature being positioned to be subject to the actuating iniiuence of the flux on both -sides of said spring; and a support for ,holding the ends of said spring in fixed relation. 6. An electro-magnet including a magnet winding; a swinging armature movable by lll@ the flux due to said Winding; a bei' spring extending transversely of the armatui'efand upon an intermediate portion of which the arma-ture is mounted at al1-intermediate portion of the armature Where theJ armaturelis in rigid connection with: the spring, the armature being positioned 'be subject to the actuating influence of the iux on both sides of said spring; and a support for said spring. `.10 In witness whereof, hereunto subscribe

Images