US2422260A - Electromagnetic operator - Google Patents

Description

June 17, 1947. w. A. RAY

ELECTROMAGNETIC OPERATOR Original Fil ed Nov. 25, 1942 I'mventor: W/z MAM A. Pny,

(Zltorneg.

Patented June 17, 1947 2,422,260 ELECTROMAGNETIC OPERATOR William A. Ray, Los Angeles, Calif., assignor fir General Controls 00., a corporation Original application November 23, 1942, Serial No.

1945, Serial No. 606,345

4 Claims.

This invention relates to low energy-consumption electromagnetic operators, and more particularly to those of the iron-clad single-workinggap type; the present application being a division of my copending application Serial No. 466,636, filed November 23, 1942; now Patent No. 2,382,664, granted August 14, 1945.

In Patent No. 2,358,828, granted to me September 26, 1944, I disclose. an electromagnetic operator, of the series working-gap type, the energy consumption of which is very small in comparison with that of electromagnetic operators of conventional form and capable of performing equivalent work; the improvement residing mainly in the provision of a core having, at its ends, enlargements forming pole-faces which are considerably greater in area than the cross-sectional area of the body of the core. The improved operation of that device is mainly due to the fact that, when the fiux density in the core (produced by a. weak magnetizing force) is at a point considerably below the knee of the magnetization curve for the core material, the flux density in the large-area pole face is substantially the same as that which could be produced by the weak magnetizing force if the cross-sectional area of the body were not reduced; reduction of the body area making possible the use of a coil winding of small mean turn diameter and correspondingly small electrical resistance. It is a general object of the present invention to apply similar principles to provide a low energyconsumption electromagnetic operator of the single working-gap type.

A more specific object of the invention is to provide an iron-clad electromagnetic operator having a plunger-type armature and embodying the principles set forth hereinabove.

Another object is to provide an electromagnetic operator, of the character described in the preceding object, which is especially adapted for energization by a pair of separate coil windings.

For full understanding of the invention, and further appreciation of its objects and advantages, reference is to be had to the following detailed description and accompanying drawing, and to the appended claims.

In the drawing, the single figure of which is a longitudinal sectional view of an electromagnetic operator embodying the invention, the numerals 3i and 32 indicate a pair of cup-shaped core portions which are intimately joined together by tightly lapping the mouth of one over that of the other, screws 33 serving to secure the Junction. Attached, as by welding, to the Divided and this application July 21,

end wallof the upper core portion 31 is a cylindrical inner core portion 34 having at its free end a cylindricalstop or head 35, of the same material as the core portion, the underside 33 of which forms the pole face of the electromagnet. Welded in a central opening through the end wall of the lower cup-shaped portion 32, and so arranged that it extends to a considerable distance from either side of the wall, is a sleeve 31 of magnetic material. A press-fit within this sleeve is another sleeve 38, of thin non-magnetic material, having at its inner or upper end, immediately above the corresponding end of the outer sleeve, a flange 33. A sliding fit within the inner sleeve is a magnetic plunger '46, the outer end of which is adapted to be connected to a, device to be operated. The plunger has at its upper end a cylindrical head 4|, also of magnetic material, the top surface of which defines with the pole face 36 the working-gap of the electromagnet. Direct engagement of the heads 35 and 4|, when the electromagnet is energized, is prevented by a non-magnetic button 42 set in he lower head; and, when the plunger is in its unattracted position as shown, the underside of its head is separated from the magnetic sleeve 31 by the non-magnetic flange 33. The adjacent surface areas of the heads 35 and H are several times greater than the cross-sectional areas of the core portion 34 and plunger 40, respectively, but the heads are preferably of such diameter that the space between them and the outer core portions is large enough to prevent material lateral leakage of flux. For energizing the electromagnet, a pair of coil windings l3 and 44, connected in aiding relation and having external leads 45, are provided; one winding surrounding the core portion 34 and the other the magnetic sleeve 31. Due to the large surface area of the sleeve 31 adjacent the plunger 40, the reluctance of the fixed air-gap between these parts is relatively low. To increase the flux-conducting capacity of the end walls of the outer core portions 3| and 32, disks 46 and 41, of magnetic material, are welded to their outer surfaces.

The embodiment of my invention herein shown and described is susceptible of modification without departing from the spirit of the invention,

and I intend therefore to be limited only by the scope of the appended claims.

I claim as my invention:

1. In an electromagnetic operator of the single for an energizing coil winding; said inner core portion being relatively small in cross-section and having at its free end a disk-like head providing a substantially plane pole face the area of which is at least several times greater than the crosssectional area of the small part of the inner core portion; a plunger-lik armature substantially coaxial with said inner core portion and extending through an opening in a wall of said outer core portion, said armature having at its inner end a disk-like head providing a surface substantially coextensive with that of said pole face and defining therewith a working-gap; said outer core portion providing at said opening an inward extension surrounding the plunger portion of the armature and in good flux-transfer relation thereto; a coil winding surrounding said small part of the inner core portion; and an additional coil winding surrounding said inward extension of the outer core portion.

2. In an electromagnetic operator'of the single working-gap type: a core member comprising a hollow outer portion formed by side walls and a pair of opposite end walls, and an inner portion extending from one of said end walls to define with said side walls a space for an energizing coil winding; said inner core portion being relatively small in cross-section and having at its free end a disk-like head providing a substantially plane pole face the area of which is at least several times greater than the cross-sectional area of the small part of the inner core portion; the other face and defining therewith a working-gap; a 4

col] winding surrounding said small part or the inner core portion; and an additional coil winding surrounding said sleeve.

0 Number 3. An electromagnetic operator, as defined in claim 2, including a sleeve of thin non-magnetic material interposed between said magnetic sleeve and the plunger portion of said armatur and extending beyond the inner end of the magnetic sleeve so as to prevent direct engagement of said armature-head with the magnetic sleeve.

' 4. In an electromagnetic operator oi the single working-gap type: a core member comprising a pair of cup-shaped portions lOined together at their mouths, and an inner core portion extending from the inner surface of the end wall of one of said clip-shaped portions in spaced relation to the side walls thereof; said inner core portion being relatively small in cross-section and having at its free end a disk-like head providing a substantially plane pole face the area'of which is at least several times greater than the cross-sectional area of the small part of the inner core portion; the end wall of the other of the cupshapedportions having an opening therethrough on the axis '01 said inner core portion; a sleeve of magnetic material joined to said last-mentioned end wall and extending inwardly from said opening along said axis; a plunger-like armature slidable in said sleeve and having at its inner end a disk-like head providing a surface substantially coextensive with that of said pole fac and defining therewith a working-gap; a coil winding surrounding said small part of the inner core portion; and an additional coil winding surrounding said sleeve.

WILLIAM A. RAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 1,333,542 Geissinger Mar, 9, 1920

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