US3133172A - Armature mounting means for electromagnetic relay - Google Patents

Description

y 1964 w. A. WILLIAMS ETAL 3, 7

ARMATURE MOUNTING MEANS FOR ELECTROMAGNETIC RELAY Filed Dec. 28, 1960 FIGI H62 INVENTORS IV/LL/AM A. VV/LL/AMS DWIGHT M HUGHEY ATTORNEYS United States Patent 3,133,172 ARMATURE MOUNTKNG MEANS FUR ELECTRO- MAGNETlQ RELAY William A. Williams, Evansville, Ind, and Dwight M. Hughey, Mount Carmel, llL, assignors to American Machine a Foundry Co., a corporation of New Jersey Filed Dec. 28, 1960, Ser. No. 79,065 Claims. (Cl. Nth-87) This invention relates to electromagnetic devices and more particularly to electromagnetic relays.

One of the objects of this invention is to provide an improved, compact, heavy duty relay.

Another object is to provide a multiple pole relay having means preventing arcing between adjacent poles.

A further object is to provide an alternating current electromagnetic device with means to maintain quiet operation without excessive chattering.

Still another object is to devise an electromagnetic device having an improved retainer bracket.

A still further object is to devise a relay, of the type having a plurality of movable contacts carried by an armature, with improved means for connecting a plurality of flexible conductors to the movable contact arms in such a manner that the life of the conductors is not decreased.

In order that the manner in which these and other objects are attained, in accordance with the invention, can be understood in detail, reference is had to the accompanying drawings, which form a part of this specification, and wherein:

FIG. 1 is an end elevational view of a relay embodying the invention;

FIG. 2 is an elevational view of the other end of the relay shown in FIG. 1;

FIG. 3 is a side elevational view of the relay of FIG. 1;

FIG. 4 is an elevational View, partly in section along line 44, FIG. 3, and with portions removed for clarity;

FIG. 5 is a top plan view of the relay of FIG. 1, showing in horizontal section a cover enclosing the relay;

FIG. 6 is a bottom plan view of the armature assembly of the relay of FIG. 1; and

FIG. 7 is a detail sectional view, on an enlarged scale for clarity, illustrating the manner of attaching a flexible conductor to a movable contact arm of the relay shown in FIGS. 1 6.

Referring now to the drawings, the embodiment of the invention there shown is a four pole, double throw alternating current relay comprising an L-shaped frame 10 supporting an alternating current electromagnet 11 and an armature 12. Frame It) is constructed from magnetizable material and has a pair of mutually perpendicular legs 13 and 14. Leg 13 is provided with a plurality of struck-out mounting lugs 1.5 by means of which the relay can be attached to a suitable support.

As shown in FIG. 2, leg 14 has an upper end portion provided with a pair of aligned, laterally spaced bearing surfaces or edges 16 which abut the bottom surface of the armature and provide a fulcrum about which the armature pivots between actuated and unactuated positions relative to the electromagnet. Edges 16 are separated by a shallow recess 17.

Electromagnet 11 comprises a laminated core 18 secured at one end to leg 13 and supporting a spool 19 on which a winding or coil 26 is wound. Coil 2t) encircles the core and is adapted to be energized with alternating current. Core 18 is of rectangular transverse cross-section, the upper end of the core being exposed and slotted to receive a shading coil 21 which provides magnetic fields of different phase. As indicated by the dotted lines in FIG. 6, the shading coil is a rectangular annulus which encircles a shaded pole face 22 located between a pair of unshaded pole faces 23. The long dimension of 3,133,172 Patented May 12, 1964 the exposed end of the core extends transversely of armature 12.

Electromagnet 11 extends perpendicular to leg 13 and parallel to leg 14, the length of the electromagnet being such that the pole faces 22 and 23 and bearing edges 16 are approximately equidistant from leg 13 so that when the armature is attracted to its actuated position, it lies substantially parallel to leg 13. Adjacent to one end, the sides of armature 12 are notched, as indicated at 24 in FIG. 6. A retainer bracket 25 is secured by a pair of rivets 26 to leg 14 and has a pair of ears 27 which extend through the notches 24 to prevent the armature from sliding laterally and longitudinally of edges 16. As shown in FIG. 2, each of ears 27 has an L-shaped end portion 28 which extends transversely of and overlies the armature to limit movement of the armature away from engagement with edges 16, the direction of such movement being generally normal to edges 16 and parallel to leg 14. The end portions 28 are operative to prevent the ears 27 from being withdrawn from the notches except upon rupture or permanent distortion of either the bracket or the armature.

Bracket 25 has a pair of lugs 29 which project outwardly from leg 14, the lugs being suitably shaped to detachably anchor one end of each of a pair of parallel restoring springs 30. The other ends of springs 30 are detachably secured to a pair of lugs 31 which extend from that end of the armature which lies opposite to electromagnet 11. Springs 30 are in tension and exert forces onarmature 12 in directions parallel to leg 14 to bias the armature into engagement with edges 16 and toward its unactuated position, such position being that illustrated in FIG. 3. As best seen in FIG. 2, bracket 25 and armature 12 are wider than leg 14. Lugs 29 and 31 are so located that the lines of force of springs 30 are separated by a distance greater than the width of leg 14 so that such forces are exerted on the armature beyond the outer ends of edges 16.

\ Projecting from the bottom surface of the armature is a circular embossed or raised portion 32 which is dimensioned and arranged to abut only shaded pole face 22, when the armature is in its actuated position, to provide an air gap between the armature and unshaded pole faces 23 for achieving maximum utility of the flux components. The positional relationship of the pole faces to the armature, when the latter is in its actuated position, is illustrated in FIG. 6.

Secured to the end of leg 13 is a molded panel 33 of insulating material, the panel being a generally rectangular block which extends perpendicular to leg 13 and parallel to leg 14. Panel 33 and leg 14 are disposed on opposite sides of the electromagnet. Armature 12 extends from leg 14 toward but terminates short of the panel. A

Panel 33 is provided with four rectangular apertures 34. A pair of fixed contact arms 35 extends through each aperture 34, the contact arms being spaced in a direction perpendicular to leg 13. Each upper contact arm carries a fixed, normally closed contact 36 and each lower contact arm carries a fixed normally open contact 37.

Also mounted upon panel 33 are a pair of terminals 38, to which are connected the terminals of coil 20, and four terminals 39 which are connected, in a manner described hereinafter, to four movable contact arms 40 carried by the armature. The outer ends of contact arms 35 and terminals 38 and 39 are each provided with a screw for attaching a conductor thereto, the ends being angularly arranged as shown in FIGS. 1 and 3 to provide convenient access of a screw driver to the screws. 7

A rectangular insulating shim 42 and a molded movable contact arm carrier 43 are disposed on top of armature 12, being secured thereto by a pair of rivets 44, the lower ends of which pass through and hold a pair of Belleville springs or washers 45 against the armature.

Carrier 43 includes a. fiat body 46 which, at its front end, has a dependent stiilening lip 47 which abuts the left edge of the armature, as viewed in FIGS. 3 and 6, and a pair of laterally spaced, longitudinally extending stiffening ribs 48. Along the rear edge, i.e., the edge away from panel 33, carrier 43 has a transversely extending upstanding ridge 41 provided with four spaced recesses 49 each of which receives the fixed end of a diilerent one of the movable contact arms 49. Each contact arm 40 is secured to carrier 43 by means of a compression plate 50 and a rivet 51, the under side of the rivets being insulated from the armature by the insulating shim 42. The ridge 43 supports the fixed ends of the contact arms so that the free ends of the contact arms extend generally parallel to body portion 46. Each contact arm is of electrically conductive spring material and carries at its free end a movable contact 52.

Each movable contact 52 is disposed between a pair of normally open and normally closed fixed contacts, the movable contacts and the fixed contacts being arranged to provide a four pole, double throw, break-make switch. The contacts 36, 37 of each set of fixed contacts are so spaced from each other that movement of the armature between its actuated and unactuated positions causes the movable contact arms to flex and provide elfective wiping action between the contacts.

When relays of the type thus far described are operated under conditions of heavy duty, there is a tendency for adjacent poles to are over. {To prevent this, panel 33 is provided with three ribs 53 on the side thereof adjacent to the electromagnet and the armature. The ribs are located between adjacent sets of contacts and extend outwardly from panel 33 a distance sufficient to prevent arcing between adjacent poles. The side ribs are aligned with stiffening ribs 43 of contact arm carrier 43. The center rib has an overhanging portion 54 which projects further from the panel than do the side ribs and is engageable with a stop member 55 located on the forward edge of body portion 46. Portion 54 and stop member 55 are arranged to limit pivotal movement of the armature in a direction away from the pole face to a predetermined angle beyond the unactuated position of the armature, such predetermined angle eing so chosen that, if stop member 55 is caused to abut portion 54, as by reason of shock during shipment, for example, the movable contact armis 4i Will not be permanently distorted and thereby disrupt the initial adjustment thereof. it is obvious that the side ribs could be identical to the center rib and have overhanging portions also.

Each of terminals 39 is connected to a different one of the movable contact arms 4%) by means of a flexible stnanded conductor 56. As shown in FIG. 3, each conductor 56 extends from its associated terminal 39 and has a loop, indicated at 57, which provides sufiicient flexibility to minimize interference with movement of the armature. If the ends of the conductors were merely soldered to the movable contact arms, the solder would run between the strands of the conductor into the area of the loop and, upon solidification, shorten the flexing length of the conductor. Under such circumstances, the solder not only decreases the flexibility of each conductor and slows up movement of the armature, but it also weakens the conductor, at the point where the solder ends, so that the conductor will eventually break at this point. To increase its life, each conductor 56 is a single length of stranded wire which is bent at its middle and has the ree ends secured to one of the .terminals 3% by soldering, conductor 56 being covered by a tubular sheath of insulating material. As shown in FIG. 7, the looped end of conductor 56 extends through an eyelet 58 having an annular head 59 and a tubular shank 6d. The end of shank 6t) away from head is crimped, or otherwise distorted, the crimp being efiective to distort the looped end of the conductor in such manner that the portion of the conductor which extends beyond shank 60 has a greater lateral dimension than that of the end of the crimp so that the conductor cannot be pulled out of or Withdrawn from the eyelet. The eyelet, in turn, extends through an opening in and is soldered to the upstanding end of the movable contact arm 40, the crimp being effective to prevent solder from flowing back through the shank onto the flexing portion of the conductor and thereby interfering with movement of the armature. Advantageously, the solder fills thespace indicated by the dotted lines in FIG. 7.

As shown in FIG. 5, bracket 25 includes a lug 61 which extends away from leg 14- and is provided with an aperture 6 2. A cover 63 is provided with a slot through which lug 61 extends, the cover being suitably shaped to enclose the components of the relay. A leaf spring 64 of angular configuration is inserted through aperture 62 and bears against both the cover and the lug to bias the cover into engagement with panel 33 and thereby secure the cover in place. Panel 33 has a pair of recesses 65 and the cover has a pair of projections 66, indicated by the dotted lines in FIG. 5, which are received in recesses 65, when the cover is in position, to prevent movement of the end of the cover adjacent the panel in a direction parallel to the plane of the panel.

When the relay is tie-energized, the armature occupies an unactuated position, which position is illustrated in FIG. 3. In the unactuared position, the forces of springs 36, which tend to rotate armature 12 in a clockwise direction, are balanced by the forces of the movable contact arms, which tend to rotate the armature in a counterclockwise direction. The stiffness of springs 3% is so chosen and the movable contact arms ill are so arranged that the contact pressure and the amount of flexing and wiping are equal when the armature is in either the actuated or unactuated position.

When the relay is energized by passing an alternating current through coil 2%, such current causes flux to pass through core 1%, legs 13 and 1 and armature 12, whereby the armature is moved, against the bias of springs 3d, from the position shown in FIG. 3 into engagement with core 13, the raised portion 32 of the armature then engaging the shaded pole face 22 in the manner previously described.

Movement of the armature 17. from its unactuated position to its actuated position causes movable contacts 52 to be first disengaged from the normally closed fixed contacts dd and then engaged with the normally open fixed contacts 37, such engagement being accompanied by suitable flexing of the movable contact arms to properly Wipe the abutting contact surfaces and prevent sticking thereof. Subsequent de-energization of the relay allows spring Sil to move the armature to its unactuated position.

A relay constructed in accordance with the foregoing description is particularly quiet in operation. It is believed that this quiet operation is due to three factors: First, shading the pole face of core 13; second, allowing the armature to engage only the shaded pole portion to provide an air gap between the armature and the unshaded poleportion when the armature is actuated; and

third, providing a three point suspension for the armature when in its actuated position, i.e., supporting the armature in engagement with the pole face and the two spaced bearing edges.

While only one embodiment of this invention has been shown, it will be apparent to those skilled in the art that many changes can be made in the details and arrangement of parts without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. In an electromagnetic device of the type described, the combination of a magnetic frame member comprising two fiat legs projecting at right angles to each other,

the free end of one of said legs presenting two aligned, transversely spaced bearing edges directed away from the other of said legs;

an electromagnet comprising a core, an energizing winding surrounding said core and adapted to be energized by alternating current, and a shading coil,

said core being fixed to said other leg, extending parallel to said one leg, and having an exposed end slotted to present at least first and second pole portions, said shading coil encircling one of said first and second pole portions, whereby said one pole portion presents a shaded pole face;

an armature pivotally engaged with said bearing edges and arranged for pivotal movement between an actuated position, in which said armature extends at least substantially parallel to said other leg and engages only said shaded pole face of said core, and an unactuated position, in which said armature is disengaged from said core;

a pair of restoring springs each attached at one end to a point on said armature adjacent a diiierent one of said bearing edges,

said springs being spaced apart by a distance substantially equal to the spacing between said bearing edges,

said springs extending generally along said one leg; and

means carried by said frame member and anchoring the other ends of said restoring springs to maintain said springs in tension to urge said armature against said bearing edges and bias said armature pivotally toward said unactuated position,

engagement of said armature with said shaded pole face and said two spaced bearing edges providing three-point support for said armature when said armature is held in said actuated position by energization of said electromagnet,

said free end of said one leg having a shallow notch between said bearing edges, whereby contact between said one leg and said armature is limited to said bearing edges.

2. An electromagnetic device comprising an alternating current electromagnet having a shaded pole "face; a frame member of magnetizable material supporting said electromagnet and having a hat leg extending parallel to said electromagnet, said leg having an end portion pro vicled with a pair of laterally spaced bearing edges; an armature mounted for pivotal movement about said bearing edges into and away from engagement with said shaded pole face in response to actuation of said electromagnet; a retainer bracket secured to said leg, said bracket being wider than said leg and including a pair of cars each of which extends laterally of and adjacent to a different one of said bearing edges, said bracket further having a pair of lugs extending generally perpendicular to said leg in a direction away therefrom, said armature having a pair of notches each of which embraces a different one of said ears to prevent said armature from sliding laterally and longitudinally relative to said bearing edges, each of said ears terminating in an end portion which overlies said armature and limits movement there of in a direction away from engagement with said bearing edges; and a pair of restoring springs each connected at one end to a different one of said lugs and at the other end to said armature and biasing said armature in a direction away from engagement with said pole face, said springs further biasing said armature in a direction generally parallel to said electromagnet and normal to said bearing edges to hold said armature in engagement with said edges.

3. In an electromagnetic relay, the combination of an l.-shaped field member; a front panel of electrical insulating material secured to said field member, said panel extending generally perpendicular to one leg of said field member and parallel to the other leg of said field member; an electromagnet mounted on said one leg of said field member and extending between and parallel to said panel and said other leg, said electromagnet including a pole face spaced from said one leg, said other leg terminating in an end portion spaced from said one leg by a distance approximately equal to the spacing of said pole face from said one leg; an armature mounted for pivotal movement about said end portion between actuated and unactuated positions relative to said pole face; a retainer bracket secured to said other leg and effective to retain said armature in operative relation to said end portion; restoring spring means connected to said bracket and to said armature and biasing said armature toward said unactuated position, said armature extending from said end portion toward said front panel but terminating short thereof; a plurality of contacts mounted on said panel; and at least two laterally spaced movable contact arms operatively carried by said armature for movement therewith, each of said contact arms carrying a movable contact engageable with at least one of the contacts mounted on said panel, said panel further including a rib which extends between the movable contacts and contact arms a distance sumcient to prevent arcing between said movable contacts.

4. A relay constructed in accordance with claim 3 and including a pair of terminals mounted on said panel, a pair of flexible stranded conductors each connected to one of said terminals, and means connecting each of said conductors to one of said movable contact arms, said last-mentioned means including an eyelet soldered to the movable contact arm, said eyelet being crimped to mechanically retain one end of said stranded conductor therein, said stranded conductor being solder-free adjacent said eyelet.

5. A relay constructed in accordance with claim 3 and further comprising a cover, said cover bearing against said panel and being provided with a slot, a lug integral with and extending from said bracket through said slot, and resilient means engaged with said lug and biasing said cover toward said panel to secure the same in place.

References Cited in the file of this patent UNITED STATES PATENTS 1,550,180 Perry Aug. 18, 1925 2,245,230 Shaw June 10, 1941 2,421,642 Obszarny June 3, 1947 2,650,957 Cohen Sept. 1, 1953 2,735,967 Lewus Feb. 21, 1956 2,837,616 Jaidinger June 3, 1958 2,896,045 Brunicardi July 21, 1959 2,952,801 Hyink Sept. 13, '1960 3,018,347 Deer et a1. Jan. 23, 1962 3,022,399 Bauer Feb. 20, 1962

Claims (1)

1. IN AN ELECTROMAGNETIC DEVICE OF THE TYPE DESCRIBED, THE COMBINATION OF A MAGNETIC FRAME MEMBER COMPRISING TWO FLAT LEGS PROJECTING AT RIGHT ANGLES TO EACH OTHER, THE FREE END OF ONE OF SAID LEGS PRESENTING TWO ALIGNED, TRANSVERSELY SPACED BEARING EDGES DIRECTED AWAY FROM THE OTHER OF SAID LEGS; AN ELECTROMAGNET COMPRISING A CORE, AN ENERGIZING WINDING SURROUNDING SAID CORE AND ADAPTED TO BE ENERGIZED BY ALTERNATING CURRENT, AND A SHADING COIL, SAID CORE BEING FIXED TO SAID OTHER LEG, EXTENDING PARALLEL TO SAID ONE LEG, AND HAVING AN EXPOSED END SLOTTED TO PRESENT AT LEAST FIRST AND SECOND POLE PORTIONS, SAID SHADING COIL ENCIRCLING ONE OF SAID FIRST AND SECOND POLE PORTIONS, WHEREBY SAID ONE POLE PORTION PRESENTS A SHADED POLE FACE; AN ARMATURE PIVOTALLY ENGAGED WITH SAID BEARING EDGES AND ARRANGED FOR PIVOTAL MOVEMENT BETWEEN AN ACTUATED POSITION, IN WHICH SAID ARMATURE EXTENDS AT LEAST SUBSTANTIALLY PARALLEL TO SAID OTHER LEG AND ENGAGES ONLY SAID SHADED POLE FACE OF SAID CORE, AND AN UNACTUATED POSITION, IN WHICH SAID ARMATURE IS DISENGAGED FROM SAID CORE; A PAIR OF RESTORING SPRINGS EACH ATTACHED AT ONE END TO A POINT ON SAID ARMATURE ADJACENT A DIFFERENT ONE OF SAID BEARING EDGES, SAID SPRINGS BEING SPACED APART BY A DISTANCE SUBSTANTIALLY EQUAL TO THE SPACING BETWEEN SAID BEARING EDGES, SAID SPRINGS EXTENDING GENERALLY ALONG SAID ONE LEG; AND MEANS CARRIED BY SAID FRAME MEMBER AND ANCHORING THE OTHER ENDS OF SAID RESTORING SPRINGS TO MAINTAIN SAID SPRINGS IN TENSION TO URGE SAID ARMATURE AGAINST SAID BEARING EDGES AND BIAS SAID ARMATURE PIVOTALLY TOWARD SAID UNACTUATED POSITION, ENGAGEMENT OF SAID ARMATURE WITH SAID SHADED POLE FACE AND SAID TWO SPACED BEARING EDGES PROVIDING THREE-POINT SUPPORT FOR SAID ARMATURE WHEN SAID ARMATURE IS HELD IN SAID ACTUATED POSITION BY ENERGIZATION OF SAID ELECTROMAGNET, SAID FREE END OF SAID ONE LEG HAVING A SHALLOW NOTCH BETWEEN SAID BEARING EDGES, WHEREBY CONTACT BETWEEN SAID ONE LEG AND SAID ARMATURE IS LIMITED TO SAID BEARING EDGES.

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