US3230329A - Electromagnetic relay with multiple spring type contacts - Google Patents

Description

2 Sheets-Sheet 1 ATTORNEYS W. J. RICHERT ETAL l 8 l B 2 3 H 5 I l 3 0 n a A 1 2 2 an a m O so S $QS E T e 3 l 3 22 7/// 7 v a VII/ 7%!!! 7 W Ed I 3 1 T 111 I 4 we I Q 9 4 IA 2\, 2 N 2 3 r a 1 4 4% MW l H/ 8 3 0 J8 ll 0 B w 6 m we 2 1/ l LY 2 Z! F 4,... MW 4 '4 Y 6 B 3 G 2 Jan. 18, 1966 ELECTROMAGNETIC RELAY WITH MULTIPLE SPRING TYPE CONTACTS Filed May 28, 1962 Q Q U Q Q3? 9 4 1 Q 2 Q Q Q Q t, 2- 0 Q 6 Q Q r u I 1966 I w. J. RlCHERT ETAL 3,230,329

ELECTROMAGNETIC RELAY WITH MULTIPLE SPRING TYPE CONTACTS Filed May 28, 1962 2 Sheets-Sheet 2 \ll-llll WALTEIZ .1. IZICHEZT 20v 5. sTEwAm; J2.

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ATTORNEYS United States Patent 3,230,329 ELECTROMAGNETIC RELAY WITH MULTIPLE SPRING TYPE CONTACTS Walter J. Richert and Roy B. Stewart, Jr., Princeton, Ind., assiguors to American Machine & Foundry Company,

a corporation of New Jersey Filed May 28, 1962, Ser. No. 198,251 4 Claims. (Cl. 200-104) This invention relates to electromagnetic relays and, more particularly, to improvements in contact arrangements and in means for actuating the movable contacts of such arrangements.

In the past, there have been devised many types of relays which are provided with a plurality of movable contact springs that are held, either due to their own bias or to some externally applied forces, in open position out of engagement with the cooperating fixed contacts. The movable contact springs are moved into engagement with the fixed contacts by some form of an actuator, such as a pusher card, which, in order to achieve the necessary contact pressures for proper operation of the relay, applies to the movable contact springs forces greater than those required to move the contacts into mere abutting engagement with the fixed contacts. That is, the actuator, upon movement of each movable contact spring from its open position to its closed position, applies a force which at first moves the movable contact into engagement with the fixed contact and then continues to apply a force sufficient to develop the necessary contact pressure.

One feature of the present invention is based upon the principle of providing a relay wherein each movable contact spring is biased by its own resiliency toward engagement with a fixed contact and the actuator is arranged to separate or open the movable contact springs. Such a relay is advantageous in comparison to the type of relays discussed above because contact bounce is minimized and the contact pressures are more uniform throughout the life of the relay since such pressures depend upon the bias of each arm and not upon forces applied by the actuator. That is, as the contacts wear during operation of the relay, the contact pressures developed due to the inherent bias of the arms are aifected only slightly whereas contact wear, in relays of the type employing an actuator to develop the necessary contact pressures, affects such pressures to a much greater degree.

In accordance with another feature of the invention, a relay is provided which, structurally, is extremely strong and rugged, this result being accomplished by having a rigid base connected across the free ends of the legs of a rigid U-shaped frame. The base and the frame are of nearly the same width and enclose on four sides most of the remaining relay components including an electromagnet, an armature, an actuator and a contact arrangement. Furthermore, the relay can be provided with a cover which, although advantageously constructed of plastic and having relatively thin walls, cooperates with and is reinforced by the frame so that the strength of the cover is also high.

Accordingly, one of the objects of the invention is to provide a new and improved electromagnetic relay of the type employing a plurality of movable contact springs that are biased by their own resiliency toward engagement with cooperating fixed contacts.

Another object is to provide a relay wherein the contact pressures throughout the life of the relay are relatively uniform.

Still another object is to provide a relay wherein contact bounce is minimized.

A further object is to provide a relay having extraordinary strength and rigidity.

3,Z3fl,329 Patented Jan. 18, 1966 "ice Another object is to provide a low-cost relay wherein, prior to final assembly of the relay, the movable contact springs and the fixed contacts are assembled so that no further adjustments are necessary during final assembly of the relay or after the relay has been assembled.

A further object is to provide a relay wherein the contact springs are biased by their own resiliency toward engagement with the fixed contacts and the springs and the contacts are constructed to provide effective wiping action.

Still another object is to provide a rugged relay having its contacts arranged to achieve maximum space efficiency while maintaining proper spacing between adjacent circuits.

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 a side elevational view, partly in section and looking along line 11 of FIG. 2, of one embodiment of the invention;

FIGS. 2, 3 and 4 are top plan views, partly in section, looking along lines 2-2, 33 and 44, respectively, of FIG. 1;

FIG. 5 is an end elevational view, partly in section, looking along line 5-5 of FIG. 1;

FIG. 6 is a bottom plan view of the relay shown in FIG. 1;

FIG. 7 is a top plan view, partly in section, illustrating a portion of the contact arrangement of the relay illustrated in FIGS. 1-6.

FIG. 8 is an elevational view looking along lines 88 of FIG. 7;

FIGS. 9-14 are detail views of other contact arrangements in accordance with the invention, FIG. 14 being an elevational sectional view along line 14-14 of FIG. 13; and

FIG. 15 is a perspective of a modified form of an actuator, FIGS. 9-15 being on enlarged scales relative to that of FIGS. 1-6 for clarity of illustration.

Referring now to the drawings, and in particular FIGS. 1-6, the illustrated relay includes a base assembly 10, a cover 11, a frame 12, an electromagnet 13, an armature 14, a restoring spring 15, a bracket 16, a guide plate 17 and an actuator 18.

Base assembly 10 includes a base 19 having mounted thereon a plurality of terminals 20 arranged in a plurality of rows parallel to each other and to the sides of the base. Base 19 is rigid and is of insulation material such as glass alkyd. The base has the configuration of a relatively thin, rectangular, flat block and, because of the relatively large number of terminals and contacts in the illustrated embodiment, is longer in one direction than in the other, i.e., the block has an elongated rectangular shape.

Terminals 20 extend through base 19 in directions perpendicular thereto and project from opposite sides of the base, the medial portions of the terminals being enlarged and embedded in the base. The upper portions of the terminals are cylindrical pins and support a plurality of contacts in a manner described below. The lower portions, although illustrated as pins, can be of any desired shape, such as flat, hooked, etc., dependent upon the particular connection requirement of the relay. The base and terminals can be assembled in a manner similar to that disclosed in copending application Serial Number 146,607, filed October 20, 1961, by Zeke R. Smith, assigned to the assignee of the present invention.

Cover 11, in conjunction with base 19, encloses the relay and protects it from dust and other atmospheric conditions, the cover being in the form of a rectangular,

inverted, cup-shaped housing. The cover includes a top wall and four side walls. At the corners of the side walls, there are provided four vertical guides 21 which terminate short of the lower edge of the cover by a distance corresponding to the thickness of base 19 so that the lower ends of guides 21 abut the top surface of base 19 whereby the lower edge of cover 11 lies flush with the lower face of base 19 and the lower end of the cover fits snugly around the base. At each end of the cover, the guides 21 are spaced apart a distance corresponding to the width of frame 12 and are adapted to frictionally engage the sides of frame 12 to frictionally hold the cover in place whereby the cover can be removed. The cover is preferably of a clear plastic mate-rial so that the enclosed components can be externally viewed. Furthermore, although the cover has been illustrated as composed of separate panels secured together, the cover obviously can be fabricated, as by molding, as an integral unit.

Frame 12 is of relatively heavy gauge sheet metal and has an inverted U-shaped configuration. The frame is magnetic so that a portion of it serves as a field member providing a flux path for the electromagnet and armature. Frame 12 includes a horizontal cross bar 22 and a pair of downwardly extending, parallel legs 23 which depend from opposite ends of cross bar 22.

The lower ends of legs 23 are of reduced Width and are received in recesses 24 provided in opposite ends of base 19, as best seen in FIGS. 4-6, the depth of the recesses being equal to the thickness of the frame so that the ends of the base and the outer or opposite surfaces of legs 23 are flush. The length of the lower ends of legs 23 is equal to the thickness of the base so that the lower ends lie flush with the bottom face of base 19.

The frame is secured to the base by a pair of screws 25, so that the base extends between the lower or free ends of legs 23. The width of the frame is nearly equal to the width of the base but is less by an amount equal to the thickness of two guides 21. Thus, the lower chamber is enclosed .on four sides by the frame and the base and the cover encloses the remaining sides of the chamber.

The distance between the outer surfaces of legs 23 is equal to the corresponding internal dimension of the cover whereby the frame and the base backs up and additionally strengthens the cover against compressive forces. Note also such strengthening is aided by guides 21 engaging the sides of legs 23.

Electromagnet 13 comprises a core 26 attached at one end to one of legs 23 and provided at its other end with an exposed pole face, a bobbin surrounding core 26 and supported thereon, and a coil 28 wound on bobbin 27, the coil having a pair of leads 29 which are connected to the upper ends of two of the terminals 20 located in the outer rows. The electromagnet is disposed in the lower chamber and extends parallel to base 19 below cross bar 22 and has its axis coincident with a vertical plane that passes through the longitudinal center line of the base and of the relay. The diameter of the electromagnet is slightly less than the width of frame 12, whereby the frame is wrapped around and protects the electromagnet.

Frame 12 has an aperture 30 located at the intersection of cross bar 22 and the one of legs 23 opposite to that upon which core 26 is mounted, the aperture being shaped to provide a pair of lugs 31 and a pivot edge 32 on cross bar 22. Armature 14 includes a flat body portion 33 pivoted at one end on edge 32 and a pair of laterally spaced, parallel arms 34 which overlie cross bar 22 and extend generally perpendicular or transversely of body portion 33. Armature 14 also includes a pair of U-shaped recesses 35 which receive lugs 31 and prevent relative movement between the armature and frame 12 in a direction longitudinally of the body portion of the armature.

The armature further includes an eyelet 36 which projects from the upper end of body portion 33 into the upper chamber and is connected to one end of restoring spring 15. The other end of restoring spring 15 is anchored by a lug 37 which projects upwardly from the body portion of bracket 16 so that the axis of spring 15, which is a helical tension spring, is substantially horizontal. Bracket 16 is of nonmagnetic material and has a T-shaped body portion including a cross bar 37 and a leg 38. Cross bar 37 extends across the top of cross bar 22 and is provided with a pair of ears 39 which are bent into recesses 40 formed in cross bar 22 and secure the bracket to the frame. Cross bar 37 lies between the free ends of arms 34 and frame 12 and serves as a stop member to limit pivotal movement of the armature away from engagement with core 26 and as a nonmagnetic shim to prevent the armature from sticking to the field member when the armature is in its unactuated position. The end of leg 38 extends through eyelet 36 and is bent to prevent the armature from being moved away from operative engagement with the pivot edge.

As viewed in FIG. 1, restoring spring 15 biases armature 14 in a conuterclockwise direction about pivot edge 32 toward the unactuated position of the armature, such position being indicated in FIG. 1. When the electromagnet is energized, as by passing a suitable electrical current through the terminals to which the leads 29 are connected, the armature is attracted and moves into engagement with the pole face of core 26, such movement being in a clockwise direction as viewed in FIG. 1 and against the bias of restoring spring 15. When the electromagnet is deenergized, the restoring spring is operative to return the armature to its unactuated position wherein arms 34 engage bracket 16.

Body portion 33 of the armature includes a lower, elongated rectangular portion 41 provided at its lower edge with a tip 42 received in an aperture in actuator 18 so that movement of the armature causes the actuator to move.

Actuator 18 comprises a main body portion 43 and a plurality of downwardly extending bearing arms 44 having their lower faces disposed in sliding engagement with the upper surface of base 19. Body portion 43 has an elongated rectangular configuration and lies parallel to base 19 so that the center lines of body portion 43 and of base 19 lie in the same vertical plane. Bearing arms 44 hold body portion 43 spaced above base 19 whereby the bottom of body portion 43 is spaced above the tops of terminals 20 and the contacts mounted thereon. Actuator 18 also includes a plurality of apertures 49 which reduce the weight of the actuator.

Guide plate 17 is in the form of a rectangular annulus and has at opposite ends pairs of laterally spaced ears 45 which are received in apertures in frame 12 so that the guide plate is supported by the frame and extends between legs 23 parallel to and above base 19 and above actuator 18. The sides of guide plate 17 are provided with downwardly extending curved abutments 46 which slidably engage the top of body portion 43 of actuator 18 and hold the actuator in engagement with base 19 to prevent movement of the actuator upwardly relative to the base.

Portion 41 of the armature extends through the guide plate and is spaced therefrom a distance sufiiciently great so that the guide plate does not interfere with movement of the armature and the actuator. Energization and dcenergization of electromagnet 13 is effective to cause actuator 18 to reciprocate longitudinally and produce relative longitudinal sliding movement between the actuator and guide plate 17 and base 19. A plurality of longitudinally extending, upwardly projecting guides 55 slidably engage the inner edges of arms 44 and confine movement of the actuator to longitudinal directions. Actuator 18 also includes a plurality of downwardly extending actuating arms 47 which, in the illustrated embodiment, comprise two parallel rows each including four actuating arms, the rows being parallel to and located on opposite sides of the longitudinal center line of the relay.

Mounted on the upper ends of terminals are a plurality of fixed contacts 50 and a plurality of movable contact springs 51. As best seen in FIGS. 7 and 8, each of fixed contacts 50 is in the form of a sleeve of suitable contact material, such as silver or a silver alloy, that surrounds the upper end of the associated one of terminals 20 and is secured thereto either by a press fit or fused metal. In the illustrated embodiment, the relay comprises eight fixed contacts arranged in two parallel rows each containing four fixed contacts, each row being parallel to and disposed on opposite sides of the longitudinal center line of the relay and forming an outer row.

Each movable contact spring 51 is of resilient, spring, sheet metal and is elongated. Each contact spring is fixed at one end to its supporting terminal so that the free end of the spring is movable parallel to and above the base, the fixed end being curved back upon itself and arranged concentric to the terminal. As best seen in FIGS. 7 and 8, the free end of each spring is curved about an axis which is parallel to the contact spring and on the side thereof opposite to the cooperating fixed contact so that, when the contact spring is closed, the abutting surfaces provide point contact.

When each contact spring engages a fixed contact, it is held by the fixed contact, as illustrated by the full lines in the upper spring shown in FIG. 7, deflected from its unstressed condition, illustrated by the dotted lines in FIG. 7, whereby the contact spring is internally stressed, due to its inherent resiliency, an amount sufficient to provide the necessary contact pressure. Upon movement from the closed position to the open position, the internal stresses are increased whereby, when the actuating forces are removed, the contact spring moves under its own bias to the closed position.

The contact springs are arranged in pairs each associated with a different fixed contact. In each pair, the contact springs alternately engage the fixed contact on opposite sides thereof. Furthermore, in each pair, the fixed ends curve away from each other and around the supporting terminals in opposite directions whereby movements of the free ends are in opposite directions when traversing from an open position to a closed position and vice versa.

Each pair of contact springs cooperates with a fixed contact mounted on a terminal located in a row opposite to the adjacent row of fixed contact terminals. That is, each pair of contact springs extends from their supporting terminals across the center line of the relay and is engageable with a fixed contact located on the other side of the center line.

Adjacent pairs of springs extend in opposite directions so that adjacent springs of adjacent pairs overlap over approximately one-half their lengths. However, the springs are spaced so that no arcing or flashover can occur under the design load conditions. Note that, although the tendency to are is greatest at the fixed contacts due to the opening and closing of the contacts, the fixed contacts are relatively far apart due to the alternating arrangement.

The terminals which support the movable contact springs are arranged in two parallel rows each containing eight terminals. These rows are spaced inwardly of the rows supporting the fixed contacts and are each located on the side of the longitudinal center line of the relay opposite to that of the associated row of fixed contacts. Each of actuating arms 47 is associated with a different pair of movable contact springs, each actuating arm being disposed between the associated contact springs, as best seen in FIG. 7. The actuating arms are arranged so that within each pair of movable contact springs, the contact springs are alternately engageable with the associated fixed contacts, whereby, upon actuation of the actuating arm, the closed contact spring breaks and the open contact spring makes with the fixed contact. Obviously, the springs can be arranged to either break-beforemake or make-before-break.

The movable contact springs are preformed before assembly and can, by use of special assembly fixtures, be fastened to their respective terminals so that, when the actuator and motor structure are finally assembled with the base assembly, no further adjustments of the contacts are necessary.

Other contact arrangements which provide sufiicient wiping action and are suitable for use in the invention are illustrated in FIGS. 9-14. Referring now to FIGS. 9 and 10, the free end portion of each movable contact spring can be flat. In this case, the fixed contact is in the form of a curved sheet metal tip 52 which has an arcuate transverse cross section that extends around the terminal through an are greater than the axis of the tip being parallel to the axis of the terminal on which it is mounted. The inner surface of the tip is secured by fused metal to the upper end of the associated terminal and is engageable with the free end of the contact spring.

In the embodiment shown in FIGS. 11 and 12, the free end of each contact spring is curved about an axis that extends transverse of the contact spring and parallel to the axis of an associated fixed contact, such axis lying on the side of the contact spring opposite to that engageable with the fixed contact. The free end has a longitudinal slot 54 that divides the end portion into tabs having different widths and therefore different resonant frequencies of vibration. Such an arrangement provides greater reliability in low level contact operation. When engaged, the fixed contact and the associated movable spring abut to provide line contact.

In the embodiment shown in FIGS. 13 and 14, the movable contact spring is the same as in the embodiment of FIG. 9 but the fixed contact is in the form of a contact button or rivet 53 which projects from opposite sides of the terminal. The upper end of the terminal is flattened, as indicated at 56, and is pierced and the rivet extends through the aperture thus formed. The contact surfaces of the rivet are spherical and provide point contact with the fiat surfaces of the contact springs. The flattened portion 56 lies substantially parallel to the free ends of the associated contact springs.

There is shown in FIG. 15 an actuator 57 having a fiat rectangular body portion 58, a plurality of weight reducing apertures 59, an elongated aperture 60 adapted to receive the tip 42 of the armature, and a plurality of arms 61 adapted to be disposed between the contact spring of each pair for actuating the same. The lower ends of arms 61 are adapted to engage base 19 to support the actuator on the base. Aperture 60 is shaped so that tip 42 prevents the actuator from twisting and thereby confines movement of the actuator to longitudinal directions. Thus, actuator 57 differs from actuator 18 because arms 61 perform the function of all of arms 44 and 47 and because guides 55 would not be needed.

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. An electromagnetic relay comprising a rectangular block constituting a base;

a U-shaped frame having its ends secured to opposite ends of said base;

a plurality of terminals mounted on said base and arranged in a plurality of longitudinal rows which are parallel to the sides of said base;

a plurality of fixed contacts mounted on some of said terminals at a location between said frame and said base;

a plurality of movable, elongated contact springs mounted on others of said terminals at a location between said frame and said base, each of said contact springs being secured at one end to a ter-, minal and extending transversely of said base so that its free end cooperates with a fixed contact mounted on a terminal located in a different row;

an actuator for moving said contact springs, said actuator being disposed in sliding engagement with said base for reciprocatory movement parallel to said base and to said rows;

an electromagnet mounted on said frame;

and means for moving said actuator including an armature pivotally mounted on said frame and engaged with said actuator.

2. An electromagnetic relay comprising a rectangular block constituting a base;

a rigid, U-shaped frame including a cross bar parallel to said base and a pair of substantially parallel legs having their free ends secured to opposite ends of said base;

a cover having an opening with one dimension sub stantially the same as the length of said cross bar frictionally secured to said frame and substantially enclosing the same, said base extending across and substantially filling said open end,

said cross bar dividing the space enclosed by said cover and said base into an upper chamber and a lower chamber;

a plurality of terminals carried by and extending through said base and including upper portions disposed in the lower end of said lower chamber;

a plurality of fixed contacts mounted on certain of said terminals;

a plurality of movable contacts mounted on others of said terminals;

an actuator for said movable contacts, said actuator including a body portion disposed above said contacts and arm means depending from said body portion and slidably engaged with said base, whereby said actuator is movable longitudinally of and parallel to said base;

an electromagnet mounted on said frame and lying in said lower chamber above said actuator;

an armature pivotally mounted on said frame and engaged with said actuator formoving the same in response to movement of said armature;

a restoring spring connected to said armature;

and a guide plate slidably engaged with said body portion of said actuator to prevent movement of said actuator away from said base.

3. An electromagnetic relay comprising a rectangular block constituting a base; a U-shaped frame having its ends secured to opposite ends of said base; a plurality of terminals mounted on said base and arranged in a plurality of longitudinal rows which are parallel to the sides of said base; a plurality of fixed contacts mounted on some of said terminals at a location between said frame and said base; a plurality of movable, elongated rcontact springs mounted on others of said terminals at ra location between said frame and said base, each of 'said contact springs being secured at one end to a terminal and extending transversely of said base so that tits free end cooperates with a fixed contact mounted on 'a terminal located in a different row; an actuator for 'moving said contact springs, said actuator being disposed between said frame and said base for reciprocatory 'movement parallel to said base and to said rows; an electromagnet mounted on said frame; and means for unoving said actuator including an armature pivotally lmOUntCd on said frame and engaged with said actuator. v 4. A relay in accordance with claim 3 including a guide plate slidably engaged with said actuator to prevent movement of said actuator away from said base.

References Cited by the Examiner UNITED STATES PATENTS 1,672,976 6/1928 Field 200-104 2,077,622 4/ 1937 Field 200-166 2,259,183 10/1941 Snavely' 200-104 2,441,614 5/1948 Baumer 200-16 2,472,709 6/ 1949 Knapp 200-104 2,490,963 12/1949 Hofgaard 200-104 2,556,716 6/1951 Viol 200-104 2,658,961 11/1953 Fisher 200-104 2,853,578 9/1958 Rommel et al 200-166 3,041,422 6/ 1962 Greshel 200-104 3,051,804 8/1962 Mayer 200-104 3,068,335 12/1962 Gregg 200-104 FOREIGN PATENTS 819,362 9/ 1959 Great Britain.

BERNARD A. GILHEANY, Primary Examiner.

Claims (1)

1. AN ELECTROMAGNETIC RELAY COMPRISING A RECTANGULAR BLOCK CONSTITUTING A BASE; A U-SHAPED FRAME HAVING ITS ENDS SECURED TO OPPOSITE ENDS OF SAID BASE; A PLURALITY OF TERMINALS MOUNTED ON SAID BASE AND ARRANGED IN A PLURALITY OF LONGITUDINAL ROWS WHICH ARE PARALLEL TO THE SIDES OF SAID BASE; A PLURALITY OF FIXED CONTACTS MOUNTED ON SOME OF SAID TERMINALS AT A LOCATION SAID FRAME AND SAID BASE; A PLURALITY OF MOVABLE, ELONGATED CONTACT SPRINGS MOUNTED ON OTHERS OF SAID TERMINALS AT A LOCATION BETWEEN SAID FRAME AND SAID BASE, EACH OF SAID CONTACT SPRINGS BEING SECURED AT ONE END TO A TERMINAL AND EXTENDING TRANSVERSELY OF SAID BASE SO THAT ITS FREE END COOPERATES WITH A FIXED CONTACT MOUNTED ON A TERMINAL LOCATED IN A DIFFERENT ROW; AN ACTUATOR FOR MOVING SAID CONTACT SPRINGS, SAID ACTUATOR BEING DISPOSED IN SLIDING ENGAGEMENT WITH SAID BASE FOR RECIPROCATORY MOVEMENT PARALLEL TO SAID BASE AND TO SAID ROWS; AN ELECTROMAGNET MOUNTED ON SAID FRAME; AND MEANS FOR MOVING SAID ACTUATOR INCLUDING AN ARMATURE PIVOTALLY MOUNTED ON SAID FRAME AND ENGAGED WITH SAID ACTUATOR.

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