US2419071A - Electromagnet - Google Patents

Description

c. l. HALL Ewcmbummrr April 15, 1947.

Filed May 2, 1944 Inventor: Chester I. Hall,

Fig.1.

His Attorney PM... Apr. 15, umv

OFFICE ELECTROMAGNET Chester H. Hall, Vischerl Ferry, N. Y., asaignor to General Electric Company, a corporation of New York Application May 2, 1944, Serial no. 533,688

3 Claims. (01. 175-336) My invention relates to electromagnets, more particularly to direct current electromagnets, and has for its object a simple, reliable and light weight electromagnet of this type.

In carrying out my invention in one form I provide operating electromagnet having an operating coil of low inductance coeflicient and a pivotal mounting for the armature of the-magnet including a grommet made of a resilient material, such as rubber, by means of which the armature is secured at one end to the magnet frame. I also provide a relatively long flexible spring having one end secured to the armature and carrying on its other end a movable contact. This elongated spring gives a more gradual buildup or pressure between the contacts after they engage each other and thereby tends to obviate bouncing oi the movable contact and arcing resuiting therefrom. I

For a more complete understanding of my invention reference should be had' to the drawing in which Fig. l is a perspective view of a contactor embodying my invention; Fig. 2 is a tragmentary side elevation view of the device 01 Fig. 1; Fig. 3 is a fragmentary view in section of a resilient mounting for one end of the armature; Fig. 4 is a view in section of a resilient armature support; Fig. 5 is an elevation view of the two halves of an interlock switch mounted on the contaetor, while Fig. 6 is a side elevation view of the interlock switch of Fig. 5 with a part broken away to show the interior.

Referring to the drawing, in one form. of my invention I provide a suitable supporting base or The electromagnet comprises a coil l2 whose diameter is substantially greater than its axial length, preferably several times greater than its length as shown in the drawing for the purpose of obtaining high speed of operation in both closing and opening of the contactor. The mag-- net core comprises a plate is made of magnet iron secured to the support It by suitable screws or bolts and having its lower end as seen in the drawing provided with a transversely extending portion It projecting outward from the support IE to a point just beyond the outer limits of the coil. On this portion 14 are two brackets ll (only one of which is shown in the drawing) to which the lower end or the armature l8 comprising a plate of magnet iron is secured by means or two grommet-like members ii and it made of.

a resilient material and bolts l9 and 20 extending through the'grommets and the bracket II. The members I! and I8 are made of a suitable rubber or rubber-like material, preferably neeprene.

As' shown in the drawing, the lower end of the armature has a width which is about the same as the diameter of the coil and the two supports Ii and is are secured in spaced-apart apertures in its lower end. As shown in Fig. 4, the grommet l1, and also the grommet ll, are provided with a central hole 2| for thebolt IS in a cylindrical portion 22 which extends through a hole 23 (Fig. 3) in the end supporting portion of the armature and preferably is slightly larger than the hole so as to secure itself permanently therein. Also, the two circular flanges 24 and 25 of the grommet are formed with their outer edges closely spaced together as shown in Fig. 4, while at the point where they join, the cylindrical portion 22, they are spaced apart a distance substantially equal to the thickness of the armature l8. Thus, when the grommet is forced part way through the hole so that the cylindrical portion lies in the hole, the flanges of the grommet are spread apart as shown in Fig. 3 by the armature between them and thereby by reason of their resiliency grip the armature between them and secure the grommet to the armature. This construction will exclude dust and foreign matter. The bolts l9 and 2b are drawn up tightly thereby to compress somewhat the grommets and seem the armature to the bracket 55. i

As shown, the bracket extends downward at an angle somewhat less than 90 degrees with the core portion l4 whereby the armature is. caused to extend normally in non-parallel relation upwardly with respect to the plate l3 which position is the unattracted position of the armature. The armature is thus biased to this position by the resiliency oi the rubber supporting grommets. It is additionally biased by means of a helical spring 26 surrounding a supporting bolt alf axial length of the coil of the movable contact and consequent arcing e engaging, when atbetween the contacts during the closing movelon the cell, the end of mans. nclrical core portion 25:: in its upper end the armature is forked to to all}? plate 53. This type of provide two projections 38 and 39 which can be up magneticlealrage utilised to operate suitable interlock switches only one which, 0, is shown. Stops for limithe movement of the armature to its limit ctsd. position are provided consisting of two ts extending through the two portions 38 and v one of whicl'a, 4!, is shown, and provided b heads against which the portions mature is in unattracted posit the pancake .ct advent ge t current uic ar than its a two casing i a. noldcd clcc wl'fcn identical together in reversed As shown, these with registering g thicknesses substantially led thickness of the remainc two parts when they are put r These portions, as indicated in Fig. 4, at opposite ends of the two assembled parts,

1r, .uial to the coin members 6 and 47 each of which has witc contacts on each side.

Also, each or" the two members is provided with semicircular depressions or grooves 48 and 45 which when the parts are put together form apertures for a longitudinally movable switch member or plunger 50 extending in a direction at right angles to the stationary contact faces thickness between each end of the bracket 32 and on the members 45 and 41. The plunger 50, the armature, after which the screws 33 and 34 40 which is mad of a molded electrically insulatare tightened, the upper end of the contact 3! ing material, extends through an aperture in an is given the desired contact wipe. The open D- electrically conducting contact bridging member sitlon or air gap is adjusted by nuts 41. normally biased by a helical spring 52 toward Another adjustment of the spring for varythe right-hand, as seen in Fig. 4, against a flange ing the force of the spring is provided by means 53 on the plunger. The other end of the spring of a screw 35 extending through an aperture in rests against a flange 54 secured to the plunger. its lower end. Thus by turning this screw against On the opposite side of the flange 54 is a helical the spring, it is bent toward the armature and spring 55 whose other end surrounds a. short the force of the spring availablefor contact prestubular spring seat 56 on a member 51. This sure thereby reduced. The screw is held in admember 51 is provided with an aperture concenjusted position by means of a lock member 35 trio with the spring seat 56 through which the having an aperture fitting over the head of the plunger extends and the member 51 fits in a screw and having its lower end secured to the recess 58 provided for it in each of the two halves. rmature by the screw 28c. Thus, when the two parts, as shown in Fig, 5,

When the armature moves toward its attracted are folded over on each other, the bridging memposition upon energization of the coil, the movber 5| cooperates with the contacts on one side able contact 3i engages the stationary contact of each of the members 46 and 41 and is biased at some predetermined point in the movement against the contacts by the spring 52. This forms of the armature and before the armature reaches a normally closed interlock switch. The switch its fully attracted position. Thereafter the ar- 69 4G is secured to the support In by terminal bolts nature continues its movement to its attracted 59 and 60 molded in the casings and connected position and thereby applies a desired force electrically to the members 46 and 41 with the through the spring 31": to the movable contact 4 plunger 50 in position to be engaged by the pro- Eil ,and also wipes the movable contact over the jection 38 or 39 when the armature is moved to stationary contact. After engagement of the its attracted position whereby the switch is movable contact with the stationary contact, the opened. armature and bracket 32 continue their move- As shown inFig, 6, the interlock switch can ment and move away from the spring 30 which be converted easily into a normally open switch i thereby bent and caused to apply an increasby simply reversing the bridging member 5|. The 8 press 130 he stationary Contact. he bridging member has its ends bent into laterally Sp i y reason 0:? its length, pro a displaced relation with the central portion segradual increase in the pressure applied to the cured to the plunger 50 these ends being on the movable contact after ts engagement With the left-hand of this central portion as seen in Fig. 4. stationary contact. This gradual application of With the bridging member reversed to the posipressure is an advantage in preventing bouncing tion shown in Fig. 5, it is turned through an angle one 44 and 45 respectively of 139 degrees about an axis perpendicular to the plunger 50. The bridging member is held by the spring 55 in spaced relation with the stationary contacts. Also, the bridging member is positioned as seen in Fig. 0n the right-hand side of flange 53 as is also the spring 52. The flange 53, and also flange 54, preferably is a metal. part provided with a slot into which fits a portion of reduced size on the plunger whereby the flanges can be readily removed for disassembly of the parts when the two halves of the casing are sepsi 1d dble electric conductor (it forms elec connection between the contact and a A member 52 secured to the base Ch ,e "i have shown a particular embodiment oi invention, it will be understood, of course, that do not wish to be limited thereto since many modifications may be made, and therefore contemplate by the appended claims to cover 1 any such modifications as fall Within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent oi the United States is:

1. An electromagnet comprising an operating coil, a magnet core member for said coil, an armature for said coil including a supporting portion provided with a hole, a member made of resilient material extending through said hole and provided with flanges on opposite sides of said supporting portion constructed and arranged to grip said supporting portion between them, said resilient member being provided with a central aperture, a support for said armature, and a bolt member secured to said support extending through said aperture for compressing said resilient member against said support thereby to secure said resilient member and said armature to said support so that said armature is biased by said resilientmember to its unattracted position away from said coil, said resilient member flexing upon energization of said coil to provide for movement of said armature to its attracted position about an axis substantially at right angles to said bolt member.

2. An electromagnet comprising an operating coil, a magnet core for said coil, a transversely extending projection on said magnet core, an ar mature member having a supporting portion provided with a hole in one end, a resilient member made of rubber-like material extending through said hole and provided with two flanges on opposite sides of armature constructed and arranged to grips-aid armature between them, said resilient member lwlng provided with a central aperture, a bolt eaten-ding through said apes ture and secured to said projection compress ing said resilient member against said projection whereby said armature is secured to said projec tion and biased by said resilient member to unattracted position away from said coil, said resilient member flexing upon energization of said coil to provide tor movement of said ture to its attracted position about an axis sub stantially at right angles to said bolt.

r in electroinagnet comprising an operating coil, a magnet core for said coil, transversely extent f projections on said magnet core, an .ner 'iber provided with two holes end, a ber of resilient material ar t ugh each oi said holes and provided two race on opposite sides of said arrna ture constructed and arranged to grip said ar mature between them, each or said resilient mem hers being provided with a central aperture, 2. bolt extending through each of said apertures and secured to one of said projections, said bolts being provided with heads for compressing said resilient members against said projections whereby said armature is secured to said projections, said projections and said resilient members being constructed and arranged to bias said armature to its unattracted position away from said coil, said resilient members flexing upon energization of said coil to provide for movement of said armature to its attracted position about an axis substantially at right angles to said bolt.

CHESTER. I. HALL.

REFERENCES CITED The following references are of record in the

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