US2857494A - Electromagnetic device - Google Patents

Description

Oct. 21, 1958 r D. A. LACE 2,357,494,

ELECTROMAGNETIC DEVICE Filed June 10, 1955 INVEN TOR. DONALD A. LACE ATTORNEY United States ELECTROMAGNETIC DEVICE Donald A. Lace, Chicago, 111., assignor of one-fifth to Nicholas M. Esser, Melrose Park, Ill.

Application June 10, 1955, Serial No. 514,433

16 Claims. (Cl. 200-87) This invention relates to electromagnetics and more particularly to an electromagnetic device having improved operating characteristics.

It is the principal object of this invention to provide an electromagnetic device having optimum operating characteristics for minimum coil size and current consumption.

An outstanding feature of the present invention resides in its adaptability to extremely minute dimensions.

These objects and additional features and advantages will become more readily apparent as the following description proceeds taken in conjunction with the following drawings wherein:

Fig. l is a side elevation of an electromagnetic device in accordance with this invention illustrated in connection with a striker for a bell, gong or other audible device.

Fig. 2 is an exploded view of the components of the device illustrated in Fig. 1.

Fig. 3 is a top view of Fig. 1 with the armature removed for clarity.

Fig. 4 is a side elevation schematically illustrating an electromagnetic device in accordance with this invention in the form of a relay.

Fig. 5 illustrates an exploded view of components for a modified form of electromagnetic device such as that of Fig. 1.

Fig. 6 is a top assembled view of the device of Fig. 5.

Referring now more particularly to Figs. 1 to 3 of the drawings, numeral 10 represents a magnetic yoke structure having a base 11, an upstanding web 12 extending from one end of the base 11 and an upper inturned member 13 which lies preferably in a plane parallel to the base 11 but of considerably shorter length. The base 11 is provided with a central bore 14, into which a reduced end 16 of the magnetic pole 17 is fitted. A pole structure is provided by preferably presecuring the pole 17 to an extension thereof 18 which preferably lies in the same plane as that of member 13 and which forms with the yoke 10 and the pole 17 the entire electromagnetic circuit or structure. The reduced end 16 of the pole 17 may be provided with an internally threaded bore into which a screw 19 may be threaded, thereby securing the structure to the base 11 of the yoke, or it may be merely upset and peened over to so secure it.

A coil 20, in the form of a solenoid, may be placed to snugly circumscribe the pole 17 before it is secured to the yoke 10 or the coil may be pre-wound directly upon the pole 17 of the pole structure 16, 17, 18.

Referring particularly to Fig. 3, it will be noted that the member 18 is shaped complementary to the coil 20 except for its rear edge 21, which is straight. The edge 21 is closely spaced from the edge 22 of the inturned member 13 of the yoke structure 10 in such a manner as to form a small air gap of the order of a few thousandths of an'inch, and in the preferred embodiment illustrated, .018". To the upstanding web 12 of the yoke there is secured by any suitable means, such as for example, screws 23, a non-magnetic, armature supporting structure Patented Oct. 21, 1958 24. This may conveniently be formed of brass and precision shaped into'a C-shaped structure having only three walls. The upper edges 25 of the lateral sides of this structure may be sloped at a small angle with respect to the plane of the top surfaces 13 and 18 of the magnetic structure, this angle being of the order of 1 to 5 and preferably 1. The connection of the non-magnetic member to the web 12 is such that the lower armature surface is always substantially tangential to the upper portion of a radius or curved pivot 26, formed in the bending over of the upper magnetic portion 13 from the upstanding web 12.

However, the upper edges 25 may be flat and lie in a plane parallel to the plane of members 13 and 18. The position of the edges 25 with respect to member 13 may be adjusted by means of the slot-like apertures 29 in the cross wall of the supporting structure 24. The range of adjustability is such that the armature position, to be described presently, is maintained at rest with respect to surfaces 13 and 18 at an angle of 1 to 5.

It is to be understood that the armature supporting structure 24 may comprise any non-magnetic material and need not be metal. It may comprise, for example, a resin or rigid plastic insulating material. The shape may also vary and may be solid so long as the slope characteristics imparted thereby to the armature remain in the range specified.

Two aligned positioning pins 27 are provided near opposite sides of the structure 24. The lateral walls of the structure 24 may also be provided with one or more pairs of aligned bearing holes 28, the purpose for which will appear shortly.

The magnetic device is completed with an armature 30 of magnetic material and is substantially rectangular but may have a rounded end to match that of the base 11. It is provided toward its rear edge 31 with a pair of notches or bores 32, which fit about the guide pins 27. It

is further provided with an intermediate aperture 33.

The armature 30, guided by pins 27, is connected to the non-magnetic'supporting structure '24 or the yoke 10 by means of a pin 35 extending through the aperture 33 and anchored at any convenient place and by any convenient means, for example on the cross Wall of the structure 24 by means of a threaded or hook and eye connection. The armature 30 is held in place under the moderate tension of a coil spring 36 between the armature and the head of the pin 35 which it surrounds. In the embodiment illustrated, the spring 36 is positioned above the armature but obviously can be positioned beneath as well. The position of the spring may be varied but it is preferable that it be positioned closer to the radiused pivot than to the rear pivot position of the armature. The rear lateral sides of the armature 30 in the rest position, therefore, are supported on the top edges 25 of the armature supporting structure 24 so that the armature bears tangentially upon the upper portion of the radiused surface 26 of the magnetic piece 13 at a small angle to the top surfaces 13 and 13 of the magnetic circuit and closely adjacent the air gap. It will be apparent, therefore, that when the coil 20 is energized, the armature will be rocked downwardly about the radiused pivot 26, immediately closing the air gap between edges 21 and 22, and storing up mechanical energy in the spring 36. When the circuit to the coil 20 is opened, the armature will move toward its rest position under the stored up energy of the spring 36 and will rock at least one or more times about its rearmost pivot edge 31 until it comes to a rest position. If necessary, a thin non-magnetic buffer material, such as aluminum foil may be placed between the armature and surface 18 to control possible sticking due to residual magnetism. Obviously, a simple self-interrupting circuit can be arranged and timed to utilize whatever number of oscillations, preferably one, in this return rocking arrangement, .as is desired.

In the embodiment shown, a striker or clapper member 40 is attached by arms 41 to a pivot shaft 42, secured through:aligned ?bores 28 in'ithe lateral walls .ofathe non-.

magnetic member 4. .A :simple' selfeinterrupted icircuit for the coil 20 may he :arranged through mating ;contacts 43son the clapper Eand anzisolated contact-:37 ton-the armature. :Such a circuit is schematicallyrillustmted Fig. 1. Depending :on the operating position-of :sucha device, .a spring 44 :to bias "the clapper toward contact position may 'be required.

The magnetic structure of ;this :device is soxefiicientr'that considerable energies-can :be transferred to the =clapper member-:40 of :-such :a magnetic ;device employing an. tex

tremely minute coil. The entire coil, whether pre-wound onpole 17 \orwound'asaa (solenoid and ;placed;thereover, need not exceed in aoutside :diameteruthe :diameter of.;a standard pencil eraser, :and is preferably wound of :copper wire .ranging about 42 to '43 wire :size,- andhaving a total resistance .of 20 .to :40 ohms, :and ,preferablyn-30 ohms. The length .of-the :arms 41 need notrexceed-fi inch and this entire magnetic device, operating self-interrupted, will drive a onetounce clapper l-to ilZzQSCillEttions perzsecond at .fllCllI'IBHt consumption lofsless than one milliampere per hour. Inctherxwords, powered'by a. single :standard ipenlight dry cell, .a magnetic device 10f this type will operate continuously for;3 00 hours or :more. Thecurrent consumed in watts,:therefore, is of=thetorder of' to A of awatt. It will be apparent thahthe compactness and efficiency of its magnetic circuit:lends this device particularly well to any need for a magnetic'structure, eitherself-interrupted or energized :and released at will, especially where extremely small dimensions ;and

currents are required. The entire .devicewith clapper need not exceed the dimensions of a OIIG-hfilfrlIlChtCllbG.

In Fig. 4 the same magnetic structure withzpairs'oi contacts- 45 and 46 illustrates .schematically :extremely efficientrelay arrangements of minutesize. InFig. 4, the insulating propertiesof a non metallic-mon-magnetic armature supporting :structure 24 may .be utilized to :mount a pair:of relayecontactssuchas =46,-operated by tthe rear ofithe armature30-byan arm-47.

Figs.:5 and:6rillustrate ,azmodified form of thermagnetic structure 'resultingin "even greater ,efiiciencies, like mumhers being assigned to like members.

Certain modifications and changes will 'be suggested hereby to thoseskilled in the art, and it iszintended that all snchrevisionsiand' modifications as fall within the true spirit of this invention'areincluded :within its scope as best defined-by the appended claims.

.I- claim:

1. An electromagneticdevicecomprising a yoke structure'of magneticmaterial having a base and.an .upstand ing web connected to one end of the .base, awpoleifixed to the base, a coil .disposed about said pole, :anrextensinn of said pole adjacent said yoke structure, and spaced therefrom by'a narrow -air. gap, an armature supporting member of non-magnetic material secured ;to1the yoke structure, and anal-mature, biasing means urging said armature toward simultaneous engagementwithtthe endssof the webdistal from thebase and a-portion atleast of said armaturesupporting-member, said armature extendingrat rest'over said extensionof said pole, adapted to :rock aboutithe yoke structurezwhen lthercoil is energized and about a pivot on the-supporting'member on'deenergiza tion of the coil.

2..An.electromagnetic device-comprising ayoke struc ture of magnetic material-having a base andan upstanding web connectedtoone end. of. the base, .a pole fixed to the base, a coil disposed .aboutsaid pole, anlextensionof saidpoleadjacent said yoke structure,.andspacedtherefrom'by a narrow air gap, an'armature supporting member'of'non-magnetic material secured to the yoke structure, and an armature, biasing means urging said armature toward simultaneousengagement'with'the ends olE-the 4 web distal from the base and a portion at least of said armature. supporting member, said armature extending ,at rest over said extension of said pole, and at a slight angle thereto, adapted to rock about the yoke structure when the coil is energized and about a pivot on the supporting member on deenergization of the coil.

3. An electromagnetic device comprising a yoke structure of magnetic material-having a base and an upstanding web connected to one end of the base, a pole fixed to the base, a coil disposed about said pole, an extensionof said :pole'adjacent said tyoke structure'and'spaced therefrom by a narrow air gap, an armature supporting member of non-magnetic material secured to .the yoke structure, -and an armature, biasing means urging said armature toward-simultaneous engagement with the ends of the web distal from the base and a portion at least of said armature supporting member, said armature extending at rest over said extension of said pole, adapted to rock about the yokestructure when the coil is energizedand about a pivot on the supporting member on deenergization of the coil, the end -of theweb -distal from :said base'being provided with a radius -.whereby a continuous and progressive magnetic contact -is maintained with-the armature as it rocks thereabout.

4. An electromagnetic device as claimed in claim 1, in -which said armature supporting member comprises an insulating material.

5. An electromagnetic device comprising a yoke'structure of magnetic material having a-base and anupstahding web connected to'oneend of the base, a pole'fixed to the base, a coil disposed about said pole, *an extension of said pole adjacent said'yoke structure and-spaced therefrom -byanarrow air gap, an armaturesupporting member of non-magnetic material secured to' the yoke structure, and an armature, biasing means 'urging said armature toward simultaneous engagement with'the "ends of the'web-distal from the base and a-portion at least of said armature supporting member, said'armature extending at rest over said extension of said pole and at' a slight angle thereto, adapted to rock about the'yoke struc ture when the coil is energized and about a pivot on the supporting member on deenergization -ofthe"-coil, the 'position'of said armature supporting member being adjustable with respect to said yoke to vary the'angle of the armature at rest with respect'to the'upper-surface of'the extension of the pole.

6. An electromagnetic device comprising a yokestructure of magnetic material having a base and an'upstanding web connected to one endof'the base, a pole fixed to'the base, a coil disposed about said pole, anextension of said pole adjacent said yoke structure and :spaced therefrom by a narrow air 'gap, an armature supporting member of non-magnetic material secured 'to'the .yoke structure, and an armature, biasing means urging said armature toward'simultaneous engagement with the ends of the web distal'from the base and a portion at least of said'armature supporting member, said armature extending at rest over said extension of said pole, adaptedto rock about the yoke structure when the coil is energized and about a-pivot onthe supporting member on deenergization of the coil, a swinging member provided with a pair of arms straddling said yoke and coil, said member being pivotally mounted'to said armature supporting member and adapted to be struck by said armature to swing it about its pivotal mounting, and self-interrupted circuit means for operating said coil ,to intermittently swing-the swinging. member about its said pivotal mountmg.

7. An 'electromagnetic device comprising ayoke structureofmagnetic material having a base and an upstandingweb connected to one end of the base,.a pole fixed to thebase, a coil disposed about said pole, an extension of sai'd'pole adjacentisaid yoke structure and spaced there from'by a narrow air gap, an armature supporting memberof non-magnetic material secured to the yoke structure, and an armature, biasing means urging said armature toward simultaneous engagement with the ends of the web distal from the base and a portion at least of said armature supporting member, said armature extending at rest over said extension of said pole, adapted to rock about the yoke structure when the coil is energized and about a pivot on the supporting member on deenergization of the coil, and at least one pair of relay contacts operable by said armature.

8. An electromagnetic device comprising a yoke structure of magnetic material having a base and an upstanding web connected to one end of the base, a pole fixed to the base, a coil disposed about said pole, an extension of said pole adjacent said yoke structure and spaced therefrom by a narrow air gap, an armature supporting member of non-magnetic material secured to the yoke structure, and an armature, biasing means urging said armature toward simultaneous engagement with the ends of the web distal from the base and a portion at least of said armature supporting member, said armature extending at rest over said extension of said pole, adapted to rock about the yoke structure when the coil is energized and about a pivot on the supporting member on deenergization of 'the coil, said armature supporting member comprising an insulating material, and at least one pair of relay contacts secured to said armature supporting member of insulating material and operable by said armature.

9. An electromagnetic device comprising a yoke structure of magnetic material having a base and an upstanding I web connected to one end of the base, a pole fixed to the base, a coil disposed about said pole, an extension of said pole adjacent said yoke structure and spaced therefrom by a narrow air gap, an armature supporting member of non-magnetic material secured to the yoke structure, and an armature, biasing means urging said armature toward simultaneous engagement with the ends of the web distal from the base and a portion at least of said armature supporting member, said armature extending at rest over said extension of said pole and at a slight angle thereto, adapted to rock about the yoke structure when the coil is energized and about a pivot on the supporting member on deenergization of the coil, at least one surface of the armature supporting member and upon which the armature bears when the coil is deenergized being provided with a slope substantially equal to the angle at which the armature extends with respect to the extension of said pole.

10. An electromagnetic device comprising a yoke structure of magnetic material having a base and an upstanding web connected to one end of the base, a pole fixed to the base, a coil disposed about said pole, an extension of said pole adjacent said yoke structure and spaced therefrom by a narrow air gap, an armature supporting member of non-magnetic material secured to the yoke structure, and an armature, biasing means urging said armature toward simultaneous engagement with the ends of the web distal from the base and a portion at least of said armature supporting member, said armature extend ing at rest over said extension of said pole, adapted to rock about the yoke structure when the coil is energized and about a pivot on the supporting member on deenergization of the coil, the means biasing the armature toward said armature supporting member being positioned closer to the web than to the position where the armature pivots on the armature supporting member.

11. An electromagnetic device comprising a yoke structure of magnetic material having a base and an upstanding web connected to one end of the base, an inturned projection extending from the other end of said web in the same direction as the base, a pole fixed to the base and having a portion extending to adjacent said inturned projection and spaced therefrom by a narrow airgap, a coil disposed about said pole between the portion extending therefrom and the base, an armature supporting member of non-magnetic material secured to the yoke structure, and an armature, biasing means urging said armature toward simultaneous engagement with portions at least of the inturned projection and the armature supporting member, said armature extending at rest over said portion extending from said pole at a slight angle thereto and adapted to rock about the juncture of the inturned projection and the web when the coil is energized and about a pivot on the supporting member on deenergization of the coil.

12. An electromagnetic device as claimed in claim 11, in which the juncture of the web and the inturned projection is radiused whereby a continuous and progressive magnetic contact is maintained with the armature as it rocks thereabout.

13. An electromagnetic device as claimed in claim 12, in which the means biasing the armature is positioned closer to said radiused pivot than to the position where the armature pivots on the armature supporting member.

14. An electromagnetic device as claimed in claim 12, including a swinging member pivotally mounted to said armature supporting member and adapted to be struck by said armature to swing it about its pivotal mounting, and self-interrupted circuit means for operating said-coil to intermittently swing the swinging member about its said pivotal mounting.

15. An electromagnetic device as claimed in claim 12, including at least one pair of relay contacts operably by said armature.

16. An electromagnetic device comprising a yoke structure of magnetic material having a base and at least one upstanding extension connected to the end of the base, a pole connected to the base adjacent said upstanding extension, a coil disposed about said pole, an extension of said pole positioned adjacent said yoke structure and spaced therefrom by a narrow air gap, an armature supporting member of non-magnetic material secured to the yoke structure, an armature, said armature being supported by said non-magnetic material and said yoke structure, the said armature extending at rest over the exten sion of said pole and adapted to rock about said nonmagnetic material and said yoke structure upon energization and deenergization of the coil, and biasing means normally urging said armature simultaneously against the said yoke structure and the supporting member of nonmagnetic material secured to the yoke structure.

References Cited in the file of this patent UNITED STATES PATENTS 501,183 Daves July 11, 1893 629,645 Baynard July 25, 1899 1,269,563 Henderson June 11, 1918 1,360,281 Evans Nov. 30, 1920 1,891,676 Lansing Dec. 20, 1932 1,937,403 Davies Nov. 28, 1933 2,287,539 Spaulding June 23, 1942 2,321,834 Marco et a1 June 15, 1943 2,458,939 Hall Jan. 11, 1949 2,526,455 Bonnano Oct. 17, 1950 2,610,995 Orsatti et a1 Sept. 16, 1952 2,617,950 Lace Nov. 11, 1952

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