US3204061A

US3204061A - Electromagnetic relay structure

Info

Publication number: US3204061A
Application number: US240637A
Authority: US
Inventors: Wheeler D Maynard
Original assignee: General Signal Corp
Current assignee: SPX Corp
Priority date: 1961-10-02
Filing date: 1962-11-28
Publication date: 1965-08-31
Anticipated expiration: 1982-08-31
Also published as: BE621618A; GB1028969A; NL132014C; DE1273069B; GB1013633A; NL281349A; GB991638A

Description

Aug 31, 1965 w. D. MAYNARD 3,204,061

ELECTROMAGNETIC RELAY STRUCTURE Filed Nov. 28, 1962 4 Sheets-Sheet 1 ,es |O eo 54 se l 5on i 5| 59 9 l 55 22-6 87 76 t 46 65 if 42 82 83 F f? 35 24 .f --1 85 n d =4 3 23g 64 22 25 34 93 9| I! 2 3e 38 94 4 @i 43 90 70 86 es I7 46 6| wvl l V59' mi 59' 72 V u V V |65 59 97 eo 54 l5 50 53 ,4 FIG. 3.

FISI. 2 62 IN VEN TOR.

Y WDMAYNARD Bww HIS ATTORNEY Aug. 31, 1965 w. D. MAYNARD ELECTROMAGNETIC RELAY STRUCTURE 4 Sheets-Sheet 2 FIG. 6.

Filed Nov. 28, 1962 FIG. 5.

FIGB.

FIG. 7.

INVENTOR. W. D. MAY NA R D HIS ATTORNEY FIGS.

4 Sheets-Sheet 3 Filed NOV. 28, 1962 FIG.|3.

CLOSED AIR GAP OPEN AIR GAP H(NI) FIG. IO.

INVENToR. W. D. M AY N A R D HIS ATTORNEY Aug. 31, 1965 w. D. MAYNARD ELECTROMAGNETIC RELAY STRUCTURE 4 Sheets-Sheet 4 Filed Nov. 28, 1962 F IG. I5.

DEFLECTION TRAVEL BACK 'OBARMATURE CONTACTS FULLY OPEN RELEASED I |00 FRONT CONTACTS CLOSE ARMATURE FULLY PICKED UP RD n mon m MA f O WN n IVI .A A Q|u M H D Y? B E M me l R a wu oc GM OO RL PS NN EE OO ER Lm ANAH l l @UT C um ||r| EC I\||\ Vl SA PO TAR LF mp0 G .II-3 Cl Nmw wRA E2 GT4 United States Patent O 3,204,061 ELECTROMAGNETIC RELAY STRUCTURE Wheeler D. Maynard, Meudon, N.Y., assignor to General Signal Corporation, a corporation of New York Filed Nov. 28, 1962, Ser. No. 240,637 13 Claims. (Cl. 200--104) This application is a continuation-in-part of my application Serial Number 142,391 liled October 2, 1961, now abandoned.

The present invention relates to relays, and more particularly to an electromagnetic relayy having improved structural and operating features. In one specific aspect, the present invention relates to an improved relay assembly of the type in which a multiplicity of movable contact blades are operated by the armature through the medium lof an insulative card.

Heretofore, electromagnetic relays, particularly those having the operating characteristics, reliability, and durability sutlicient for use in railway signaling or code communication systems for example, required a number of machined parts, considerable skill in their assembly, and intricate post-assembly adjustment. The most common of these adjustments after assembly, for example, were to the armature biasing means to insure proper loading pressures, to the relay Contact blades for insuring proper alignment and the desired contact travel and loading pressure, and adjustment to the residual, working and hinge air gaps of the armature to obtain proper armature travel for the desired operation.

ln present day complex communication or switching systems, relay requirements have become more rigid. For example, the relays must be relatively small and compact, be able to control a multiplicity of circuits, be versatile in their operation, be able to be mounted in close relation with one another, have rapid operating characteristics for required applications, should be so constituted that they can switch solid state devices reliably, and also maintain their reliability in operation for long periods of time.

The purpose of the present invention is to provide an improved relay which does not require any post assembly adjustment, is easily and rapidly assembled from parts that can be mass produced, is able to meet the requirements necessary for exacting applications, and which remains reliable in its operation for long periods of time.

In furtherance thereof, one of the objects of the present invention is to provide an improved relay that is so constructed that its separate component parts are so configurated to be capable of being assembled without skill in precise and proper relationship, with each part having means for precisely registering with another to provide a compact unitary structure, the operating characteristics of which are insensitive to minor production variations.

Another object of this invention is to provide an improved relay wherein the armature loading pressure during operation is relatively uniform throughout each predetermined portion of armature travel.

Another object of this invention is to provide an improved relay wherein the contact pressure is relatively uniform throughout their entire limits of travel.

Another object of this invention is to provide an improved relay assembly Which eliminates the need for adjusting the air gap and travel of the armature.

Another object of this invention is to provide an improved relay assembly whereby the various contact blades can be atiixedly and retainedly positioned in proper and precise alignment in their respective individual insulating mounts with zero tolerance and to remain in such precise position, not only when completely assembled, but when the individual mounts are being handled during assembly.

A further object of this invention is to provide an improved relay having operating characteristics capable of operating solid state devices reliably.

A further object of this invention is to provide an improved relay assembly having built-in arc suppression means.

A still further object of this invention is to provide an improved relay wherein the relative positioning of all of the movable components of the relay is precisely fixed by virtue of features inherent in the structural make-up of the relay.

A still further object of this invention is to provide an improved assembly and means for allixedly attaching the insulative card that is carried by the armature, to operate the contact blades.

A still further object of this invention is to provide an improved relay assembly which permits the relay to be used in varied applications, and is made up of cornponents that are either molded or stamped and require no machining.

Other objects of this invention will become apparent from the specification, the drawings, and the appended claims.

In the drawings:

FIG. 1 is a front View of a relay according to the present invention with parts cut away to show various structural features of the relay when assembled;

FIG. 2 is a sectional view of the relay taken along line 2-2 of FIG. 1 and viewed in the direction of the arrows;

FIG. 3 is a sectional view of the relay taken along line 3--3 of FIG. l and viewed in the direction of the arrows;

FIG. 4 is a fragmentary sectional View taken along line 4-4 of FIG. 3 and viewed in the direction of the arrows to illustrate how the relay armature is operatively connected to the relay core;

FIG. S is a rear view of the relay;

FIG. 6 is a fragmentary sectional View taken along line 6 6 of FIG. 5 and viewed in the direction of the arrows to illustrate the arc suppression means provided in the relay;

FIG. 7 is a fragmentary sectional view taken along line 7-7 of FIG. 5 and viewed in the direction of the arrows to illustrate the mounting of the individual relay contact blades adjacent the rear end of the relay;

FIG. 8 is a fragmentary sectional view taken along line S-8 of FIG. 5 and viewed in the direction of the arrows to illustrate the mounting of the terminal plates for the relay coils;

FIG. 9 is an enlarged isometric view of one of the mounting members employ-ed in the relay to show its configuration for holding the contact blades in proper aligned position for assembly and illustrating fragmentarily one Contact blade in such position;

FIG. 10 is a fragmentary front view showing one modified arrangement for spring biasing the stationary contact blades toward their released position;

FIG. 1l is a cross-sectional fragmentary view of a further modilication for spring biasing the stationary contact blades toward their released positions;

FIG. 12 is a fragmentary sectional view of a still further modiiication spring biasing means for a contact blade assembly;

FIG. 13 is `a graph illustrating the operating characteristics of a relay constructed in accordance with the present invention;

FIG, 14 is a graphical illustration of typical load and pull curves for a relay constructed -in accordance with one embodiment of lthe present invention;

FIG. l5 is a graph .illust-rating the relationship between the force and deformation of an elastic body; and

FIG. 16 illu-strates a general form -of external energizing circuit for the relay embodying the present invention.

seo/toer Generally speaking, and without attempting to limit the scope ott the present invention, the relay is comprised ot an elongate core of rectangular cross-section having a pair of coil structures positioned intermediate the ends thereof. An armature, also of substantially rectangular cross-section, is opena-brly connected to the core by inserting one end of the armature through an enlarged portion of an irregularly .shaped opening provided adjacent one end of the core. The armature Iis retained in such position by a pair of mating pilas-tic blocks which `are so formed lto embrace intimately the upper and lower faces of t-he core adjacent one end thereof a portion of one block extending into the irregular opening of lthe core. One of the mating lplastic members and the ar-mature has a portion for retaining a `spring to hold resiliently the armature against those edges of the portion of the irregular opening of the core on which it is adapted to pivot during operation. This `assembly precisely positions the armature without the necessity of adjusting the hinge air gap.

A Iplurality of molded plastic insulating members or 'wafers are so congurated to be stacked in intimate relationship on the upper and lower faces of the pair of mated blocks Iwith eac-h insulating member holding in precise alignment a plurality of elongate metallic contact blades. Thus, when the .fixed end of the rel-ay is completely assembled, the elongate metallic contact blades extend longitudinally of the core in spaced relation ,from both the upper and lower lfaces thereof.

Each of the plastic insulating members has a plurality of shallow recesses or grooves for receiving the xed ends of the contact blades. Each contact bdade is hel-d in precise alignment in its respective slot or recess by a resilient member 4integral with the insulating Wafer lfor assembly. In :use the alignment is maintained against external forces such as handling and curve strain by sharp projections or chisel points which embed into the contiguous surface of the wafer. One of the mated blocks is also provided with a pair `ot circular recesses to receive a non-linear resistive element which electrically connects to the terminal plates of the energizable coils to provide a -means `for suppressing the arcing of the contacts utilized to energize and deenergize Ithe relay.

The stacked insulating members and the mated blocks are fastened permanently to the core in assembled position by a `set of elongate studs which extend through aligned holes in each individual member land which are riveted at one end. Once the rivets are set, the assembly of the fixed end, or rear portion of the relay is completed.

The working end or forward portion of the relay is comprised of an integrally formed molded frame having generally rectangular external contiguration similar to that of the stacked assembly at the rear end or r'ixed end of the relay. This `frame has `a plurality of spaced partitions to form grate-like openings and a single larger central opening which is generally rectangular but has shoulders and raised surfaces on the side walls. The trame is positioned through the `central opening adjacent the front end of the core accurately by the yshoulders on the sidewall of the opening cooperating with the core. This frame is :fastened thereto by `the force of an arcuate spring member that is Iwedged between opposing surfaces of the core and the walls of the large central opening. When in this position the free ends of the contact blades each extend .through one of the grate-like openings of the frame. The released position of the armature is determined by the internal surface of the walls ot the larger central opening. A coil spring engages the armature and the opposite wall of the central opening to bias the armature to this released position.

In the illustrated embodiment of the invention there are two closely spaced horizontal rows ot so-called xed contact blades above the core, and two closely spaced horizontal rows of so-called rixed contact bla-des below the core. yEach contact blade of one row is aligned with a cor-responding contact blade of the other row to constitute `front and back contacts respectively. Spring means are mounted in the frame to bias each fixed contact blade in engagement 'with the .adjacent surface of the Wall of the opening through which the Contact blade extends. Extending through an opening interposed between each of the iront and back contact blades is a movable contact blade for engaging a lfront or back Contact `selectively in response to the operation of the relay.

A plastic card having a plural-ity of horizontally extending slits, arranged in rows and columns, each of which is positioned to receive a projection of a movable contact blade, is provided with a central rectangular opening for mounting on the t'ree end of the armature. The plastic card has an integrally formed finger that projects resiliently into the central opening and which lits in a hole in the end of the armature when the .card is positioned on the armature. The projections of the movable contact blades are locked in position in .the slits. The projections on the contact blades are so formed that the card is locked in operative position by `shifting it slightly to one side. The plastic card iixes the position of the movable contact blades relative to the armature so that when the `armature is in its released position the contact elements on the movable Contact blades, engage contact elements on the back contact bla-des to cause each of them to be lifted slightly from the wall or edge of its opening against the fonce of the spring means positioned in the Iframe. When .the armature is picked up, the movable contact arms disengage the back contacts to permit them to engage the wall of their respective openings through the pressure of the springs, and the contact elements on .the movable contact blades engage and lift the `front contact blades trom the wall or edge of its opening against the torce of the Ispring means.

ln accordance with the present invention, the individual spring means in the 'frame lare `so constituted that they are deflected sufliciently w-hen positioned in the openings to provide the proper contact pressure when the movable contact blades are in engagement with the trent or back contacts depending upon the position of the armature. This pressure, which is termed armature loading pressure is further able to be more accurate and provide greater stability to the so-called fixed contact blades because of the position of each of the spring means relative to each other and their position ot alignment with the air gap of the relay `close to the working ends of the contact blades. Thus, the contact blades are merely hinges and the flexibility factor inherent in the contact blades themselves is reduced to an absolute minimum.

The .spring means also are so fonmed that they have relatively low spring constants, that is, constants of proportionality which relate the `force exerted by the springs to the amount o-f spring deflection. In brief, they are lso-called low rate `spring means. Because the amount of spring deflection, during relay operation, is small compared to the amount .the springs are deected when in assembled position, the exerted spring pressure varies minimally during relay loperation from the values preset when inserted. This prolongs the life of the relay, because a wearing of the contact elements on the blades after continued operation does not appreciably affect the contact and armature loading pressure. These desired armature loading and contact pressures are accurately determined by the cooperation of the springs in their compressed condition with the inner face of the plastic molded .structure between which they are compressed.

'The residual air gap of the relay, that is, that which exists when the relay armature is in 'its energized `or picked up position is accurately determined by covering that portion of the surface of the armature that is in registry with the magnetic air gap with a thin accurately dimensioned layer of nonrnagnetic material. This elimi- S hates necessity for adjusting this air lgap by means of pins or the like.

-Referring in detail to FIGS l through 9 by numerals of reference, the relay is comprise-d of a core 10, which may be stamped out from appropriate rllat stock. The stamped core is an elongate metallic bar substantially rectangular in configuration and cross section, which has an irregularly coniigurated opening 1'1 adjacent its right- :hand end and a U-shaped recess |12 at its left-hand end, as viewed in FIG. 3. Centrally disposed on the core 10 are a pai-r of spools 14 which have :a generally rectangular central opening for slidably receiving the core 10. An energizing coil 15 is wound on each :off the spools 1'4. An elongate armature that is generally referred to at 16, is substantially rectangular in cross-section and is bent to have a :substantially L-shaped configuration, with its short leg '17 at the right-hand end, as viewed in FIG. 2, and its longer leg having an off-set rportionIS at the lefthand end thereof. The armature .16 may be stamped out and formed simultaneously with a progressive die. The right-hand leg 11:7 of the amature 16 has a pair of inwardly extending notches or recesses 1-9 at opposite side edges (IF'IG. 4), which notches are slightly wider than the thickness oif the core |10. In assembling the armature 16 in operative position, .the short leg 17 is inserted through the irregular opening .1K1 at its enlarged portion which is defined by side wall portions 20 (FIG. 3), land then shifted to the left as viewed in FIGS. .2 and 3 so that shoulders 21 of the core 10 engage in .the notches 19 of .the armature leg 17, and surface portion 212 of the armature leg y17 rabuts against tforward wall 23 of the core opening 1-1 which wall or side edge extends trans- Iverse .of the axis of the core 10.

With the wound spools 14 and the armature 16 so posi-tioned on the core 10, a molded block 24, of insulating material, is positioned on the core I10 in registry with the opening 111. This molded block 24 and the other insulative members hereinafter mentioned lare preferably a plastic having a high melting point land low expansion characteristics, such as a polycarbonate resin, which may Ibe formed by injection molding. The block 24 has an irregularly shaped integrally formed projection 25, the

`configuration of which substantially corresponds to the irregular opening `111 `of the core I10, and is best illust-rated in FIG. 3. The projection 25 extends Ithrough the irregulanly shaped opening .11 of the core 10 rearwardly of the armature 16, with its side faces adjacent the side wall portions 20 and 29 of the opening 111 in the core. Front faces `2.6 of the .projection 25 loosely contines the armature 1:6 in its mounted position on the shoulders 21 of the core '10. The plastic lblock 24 `also has integrally lformed tubular projections 27 that fit into holes 28 of the core .10 to properly position it on the core. A spring 30 is compressed in a chamber 31, rwhich chamber is formed by .a forward wall 32 lon the projection 25 of the block y24 :and the rear surface of the short leg 17 of the armature k16 so that the axis of the spring 30 is substantially in registry with .the uppermost portion of the transverse side wall 213 of the core opening 1'1. A spring seat 33 which fits in `a square cavity in the armature leg 17 and Ian appropriate project-ion (not shown) on the wall 32 retains the spring 30 in position. The force of the spring 30 resiliently biases the armature in its proper hinged or `pivotal position against the forward edge 2'3 of the irregularly shaped opening 111 to engage the `shoulders 21 of .the core `10. This assembly renders unnecessary any adjustment of the hinge air gap.

A square headed mounting bolt 134 is positioned with its head in `a recess 35, .the forward waill of which is rear 'face 32 of the projection 25 of the molded block 24 so that its shank extends rearwardly through the rear narrow -channel of the irregular opening 11 of .the core 10. A sleeve 36 may be inserted in the cavity 35 to better secure the holt 134 against movement and rotation.

Another molded block 38 of insulating material which is of similar overall length and width to .the .plastic block 24 is positioned against the under plane surface of the core 10 as viewed in the drawings. This block 38 has a shallow recess similar to the ycross-sectional configuration of the projection 25 of the block 24 and tubular projections similar to those referred to at y27 for block 24 so that when the block 38 is pressed -against the under surface of the core '10, it mates with .the block 24 as viewed in FIGS. 2 and 5.

The block 24 has a pair of arcuate recesses 40 formed in its upper surface to receive discs of material 41, such as Thyrite, for example, which has the property of providing high resistance to low operating voltage values, while providing low resistance to surge voltages. The discs 41, when seated in the recesses 40, are substantially flush with the upper surface of the block 24 as viewed in FIG. 6. The upper surface of the block 24 and the lower surface of the block 38 are provided with irregularly shaped shallow recesses into which correspondingly configurated terminal plates 42 (FIG. 8) and terminal plates 43 seat. Each of the

terminal plates

42 and 43, which may be stamped from sheet copper has a laterally projecting ear 44 to which a connector 45 of the windings 15 is attached. Each of the

terminal plates

42 and 43 also has a rearwardly extending projection 46 for connection to an external source of energy for energizing the windings 15. Thus, the terminals f-or energizing each of the windings 14 includes a terminal plate 42 and a terminal plate 43.

The projection 25 of the molded block 24 also has a pair of cylindrical bores, each of which communicates at the upper end with a respective recess 40 and at its lower end with the lower surface of the block 24 in registry with a bore extending through the block 38 to form an elongate bore 47 (FIG. 6) when the

blocks

24 and 38 are in mounted position on the right-hand end of the core 10. A spring 48 is inserted in the long cylindrical bore 47 and is slightly compressed to be in good contact with the disc 41 and a respective terminal plate 43 positioned on the lower surface of the block 38. The spring 4S also urges each disc 41 in good contact with its respective terminal plate 42. Thus, the energizing circuit for each of the windings 15 is electrically shunted by a path that extends from a terminal plate 42, disc 41, spring 48, and a terminal 43. During operation, this assembly, which is built-in at the xed end of the relay, prevents excessive arcing at contacts such as those illustrated, by way of example, in the general external energizing circuit shown in FIG. 16 that are used to control energization and deenergization of the relay windings 15.

A plurality of plastic members or wafers 50, which are rectangular in configuration and of such a dimension as to be co-extensive with the perimetral surfaces of the molded

blocks

24 and 38, when assembled, are positioned in stacked relationship on the upper and lower surfaces of the

blocks

24 and 38 respectively. Each of the plastic members or wafers 50, between which contact blades such as 54 and 60 are positioned as hereinafter described, have tubular projections 51 which lit into counter-bored recesses of adjoining wafers or beds 50 when stacked in proper position. Nested and stacked against the outer-most insulator wafers or beds 50 are insulator wafers or beds 52, each of which has tubular projections for nesting in the counter-bored tubular projections of its adjacent bed 50. The members 52 have a rectangular recess in one face for receiving a rectangular plate 53. A set of elongate rivets 49 are inserted through suitable openings in the plate 53 and the elongate cylindrical bores formed by the counter bored tubular projections of the members 52, beds 50, and

plastic blocks

24 and 38 to clamp the assembly together, and thus complete the assembly of the fixed end of the relay. The spring plate 53 accommodates thermal expansion and contraction while maintaining tightness of the assembly.

Each of the molded plastic beds 50 is contigurated to retain a plurality of the elongate

metallic contact blades

54 or 6@ stamped from flat sheet stock of suitable thickness and after conventional contact elements such as 59 are fastened thereto, they are ready for assembly without the necessity of forming or pretensioning. In the illustrated embodiment of the invention each of the wafers or beds has shallow recesses or slots for holding three of the contact blades, such as 54 or 60. Each of the slots has a side wall 55 against which the

Contact blades

54 or 66 engage when in the proper precise alignment. An integral projection 56, extending into the slot from each of the side walls 55, ts in a notch in the edge of each of the Contact blades 54 to insure that the contact blades are in their proper longitudinal position. The side wall opposite to side wall 55 of each of the slots is provided with an integrally formed finger 57 which normally extends resiliently into the slot, but when a contact blade such as 54 is positioned therein, the linger or projection 57 is urged out of the slot to engage against the edge of the contact blade 54. The force of the finger 57 not only holds the contact blades in intimate engagement with its respective wall 55 for proper precise alignment, but also prevents the inserted contact blade from dropping out of its respective slot or recess while the various plates are being stacked on top of one another and on the

blocks

24 and 38 during assembly. By present manufacturing techniques, these critical surfaces of the insulating members 50 can be made parallel to each other with a high degree of accuracy, and, by means of the resilient fingers 57, the various contact blades are easily assembled in precise parallel alignment with zero tolerance.

Each of the

contact blades

54 and 60 are provided with projections 59 which are formed during stamping and embed in the respective recesses of the wafers 50 so that when the iixed end of the relay is assembled, the

blades

54 and 60 are fixed in precise alignment against external forces.

It will be noted that the working or left-hand end of the contact blades 60, as viewed in FIG. 2, each have a longitudinally extending flat finger or projection 61 (FIG. l) which has a laterally extending hook portion 62; and during assembly an insulating bed 50 carrying the contact blades is interposed between those carrying the contact blades 54.

The working or front end of the relay assembly includes a molded member 63, which may be made of the same insulating material, as the fixed end of the relay.

The member 63 is substantially a rectangular frame that is open at the front and back and has integral partitions arranged to form a grate-like structure. The frame 63 has a generally rectangular central opening 64, the upper wall of which is comprised of an integral partition 65 and the lower wall of which is comprised of an integral partition 66. Parallel to and spaced between the top perimetral wall of the member 63 and the integral partition 65 are a pair of narrow parallel partitions or

cross members

68 and 69. Also, parallel to and spaced between a partiti-on 7@ and the bottom perimetral wall of the member 63 are a pair of spaced narrow parallel partitions or

cross members

71 and 72. Vertically extending spaced integral partitions 73 connect

partitions

65 and 70 to the top and bottom of the member 63 respectively and to the

narrow partitions

68, 69, 71 and 72 to complete the gratelike structure so as to provide a plurality of rectangular openings both above and below the core 10, through which the contact blades extend. These vertical partitions provide strength and rigidity to the member 63, particularly the

narrow partitions

64, 69, 71 and 72.

The member 63 is mounted on the left hand or working end of the core 10 by inserting the core 10 and the free end of the armature 16 through the central opening 64 until rectangular notches 73 (FIG. 3) in opposite side edges of the core 1G are in registry with rectangular abutments or shoulders 74 integrally formed in the side walls of the opening 64. The free ends of the

contact blades

54 and 60 are guided into respective openings such as formed by the

narrow cross members

68 and 69, and the

cross members

71 and 72. The core 10 and member 63 are then shifted relative to one another so that the core 10 engages at its under surface inwardly extending ridges 75 formed integrally with the side walls of the opening 64 fore and aft of the shoulder 74 and extending coextensively with the depth of the side walls of the memer 63. The ridges 75 are accurately molded so that their upper surface when engaged by the bottom surface of the core 10 precisely position the core 10 relative to the member 63. To fasten the member 63 to the core 10, an arcuate spring 76 is forced into the rectangular opening 64 in the space between the upper surface of the core 10 and the partition 65 with the edges of the spring 76 engaging ridges 77 integrally formed adjacent the top of the opening 64. The force of the spring 76 secures the member 63. The member 63 is held in precise longitudinal position by the abutments 74 in the notches 73 of the core as aforementioned. When the member 63 is so positioned, spools 14 carrying the coil windings 15 are confined in precise position on the central portion of the core 16 between rear edge 80 of the block 63 and the forward surface of

blocks

24 and 38 at the fixed end of the relay.

The offset portion 18 of the armature 16 engages the upper surface 81 of the partition 66 to register accurately the dropped away or released position of the relay armature.

Referring to FIG. 2, a low rate coil spring 82 is compressed, during assembly, between a spring seat 83 on surface 84 of the partition 65 of the molded member 63 and a spring seat 85 mounted in an opening in the offset portion of the relay armature 16. This spring 82 is provided for continually biasing the armature 16 toward its released position wherein its underside rests firmly on the surface 8l, of the molded member 63.

When the molded member 63 is positioned on the core 10 as described, the working ends of the front contact blades 54 are positioned in the respective openings between the top of the member 63 and the narrow partition 68, and also are positioned in the openings below the core 10 between the partition 'l0 and the partition 71. The back contact blades 54 are positioned in the openings between the narrow partition 69 and the partition 65 above the core 10, and the partition 72 and the bottom of the member 63, respectively below the core 10. The so-called movable contact blades 60 are positioned between the

partitions

68 and 69 and the

partitions

71 and 72, respectively.

The upper surfaces of the

partitions

68 and 71 respectively are engaged by the front contact blades 54 to accurately register their released or unengaged position. Back contact arms 54 engage the undersurface of the

partitions

69 and 72 when released to accurately register their released positions. To minimize manufacturing variations, the surfaces of the molded block 63 which register the position of the relay parts, such as the core 10, the contact blades 54, and the armature 16 are arranged for the least accumulation of tolerances and to negate the variation in thickness of parts where possible.

Specifically, the distance between the upper surface of the shoulders 75 and the upper surface of the partition 66 determines the open air gap of the relay without regard to variations in thickness of the core 10 or the partition 66. Only a variation in the thickness of the portion 18 of the armature 16 would affect the dimensions of the open air gap and the travel of the armature. However, even if there were slight variations in this thickness the operating characteristics of the relay are not adversely affected as is described hereinafter. Also, as long as the upper surface of the

cross members

68 and 71, and

,the lower surface of the

cross members

69 and 72 are 9` precisely positioned from the upper surface of the shoulder 75, the upper surface of the portion 66 and from each other, the thickness of the

cross members

68, 69, 71 and 72 may vary without aiecting the intended operation yof the relay.

In the preferred embodiment illustrated in FIGS. 1 through 3, coil springs such as 86 and 87 are inserted in the frame 63 to constantly urge front and back contact blades 54 respectively toward their released position. Springs 86 are inserted between each of the front contacts 54 and the top wall of the frame 63 and the partition 70 respectively. Springs 87 are inserted between each of the back contacts 54 and the bottom wall of the frame 63 and the partition 65 respectively. Circular projections or spring seats are formed integral with the inner face of the top and bottom of the frame 63 and the upper and lower surfaces of the

partitions

65 and 70 and on the front and back contact blades 54 so that the

springs

86 and 87 are secured close to the base of each bifur- Acated portion of the contact blades 54. The bifurcation is provided to insure reliability of contact. These coil springs 86 and 87 which have low spring constants, Iare of such a length that they are compressed a considerable distance when inserted in position so that the desired loading pressures are continually being exerted against the blades 54 4and 60. Thus, the exerted spring pressures remain substantially constant over their entire operating range because the amount of spring dellection, during relay operation, is small compared to the spring deection when assembled. Therefore, there is no need for relay adjustment after -assembly to obtain the desired loading or contact pressures. Also, there is no need for adjustment to maintain the desired loading or contact pressures, if the silver contacts elements 50 have become Worn because of continued operation.

To illustrate the relatively uniform contact and loading pressure over the total operating distance of the armature, reference is -made to FIG. l5. It is known that the elongation or compression, in the deformation of an elastic body is proportional to the force per unit area. Thus, if the amount of force F of a spring is equal to a constant K times the amount of the deflection of the spring D, and the constant is low, the pressure exerted by the spring will increase as illustrated by line 99 of the graph of FIG. l5 as the spring is compressed or deflected over its entire range from point C on the graph of FIG. to point D. However, in accord-ance with the present invention, the

springs

86 and 87 are compressed a distance Which may be represented from the point C to point E when the contact blades 54 are in their released position. Therefore, during the operation of the relay the amount of further spr-ing deflection or compression is only that which occurs between the points E and E. Thus, it is apparent that the force F varies only slightly during the entire travel of the contacts. This is represented by the slight variation in force accuracy between the arrows designated lat I. In actual practice, a spring such as 86 and 87 is compressed approximatey 90% of its total movement or compression when inserted and its operating range is approximately 5%. When compressed as above, in one practical application, the spring exerts substantially grams of pressure on the front and back contacts 54 over their entire range of travel. Spring 82 for biasing the armature is suitably selected to have similar characteristics.

As shown in FIGS. 1 through 3, the movable contact blades 60 by their projections 61 t in slits of a movable card 90, made of suitable insulating material, carried on the extend-ing left-hand end of the armature 16. The movable card 90 is mounted on the larmature 16, and, in proper engagement with movable contact blades 60, by rst sliding the movable card 90 over the projection 61 of the movable contact blades 60 and the projecting end of the armature 16 and then, displacing the movable card 90 to the right, as viewed in FIG. 1, so that the movable card slides into slots formed by the hook portion 62 of the projection 61 (see FIG. 3) provided in the left-hand ends of the movable contact blades 60. This card 90 is then held firmly in its assembled position by a resilient projection or linger 92 on card 90 which finger engages a hole 93 in the larmature 16 when the card 90 is properly positioned. This movable card 90 is also provided with protruding pockets 94 (see FIGS. l and 2) for receiving a relay identification card (not shown).

As shown in the accompanying drawings, with the windings 15 deenergized, the relay armature 16 is maintained in its normal released position (as illustrated) by coil spring 82 which although larger than the

springs

86 and 87, but compressed to have similar characteristics, continually exerts its predetermined spring pressure down- Wardly on the armature 16 and thereby biases the armature 16 against the upper surface 81 of the partition 66 of the front molded block 63. In this position, the movable card 90 is in its lowermost operating position and thereby causes movable contact blades 66 to engage back contact blades 54, moving these back contact blades 54 away from their unengaged positions Ias delined by the lower surfaces of

partitions

69 and 72. In this operation position, coil springs 87 provide .the desired contact pressure necessary to insure good electrical contact between the movable contact arms 60` and the back contact blades 54, and furthermore, in conjunction with coil spring 82 provides the desired armature loading pressure, while the armature 16 is in its released position. Referring to FIG. 2 it will be noted that with the armature 16 thus released, front contact arms 54 are held rmly in their unengaged position; i.e. against the associated upper surfaces of

partitions

68 and 71 of front molded block 63, by low rate coil springs 86.

If the rel-ay windings 15 are now energized, armature 16 is attracted toward the underside of the relay core 10, by the resulting magnetic ilux flowing through the series magnetic circuit formed by core 10 and armature 16. From the description already set forth, -it should be obvious that the travel of armature 16 has been accurately set by registering the desired armature release position (surface 81 of the partition 66 of the molded block 63), and the position of the left-hand end of the relay core 10 (ridge 75 in the central opening 64 of the front molded block 63). Furthermore, and with reference to the accompanying drawings, it will be noted that the working air gap of the relay has a relatively large crosssectional area as compared to the length of the air gap, thus preventing any relatively rapid changes of the magnetic pull on the relay armature 16 during energization of the windings 15 (see pull curve 110 of FIG. 14 hereinafter described).

The movable card 90 now carries movable contact blades 60 in an upwardly direction to break the contact between the movable contact blades 60 and the back contact blades 54, and then make contact between the movable contact blades 60 and the front contact blades 54. It will be noted, from the accompanying drawings and the description previously set forth, that until back contact blades 54 engage the underside of partition-

s

69 and 72 respectively in the front molded block 63, a good electrical contact is maintained between the movable contact -arms 60 and the back contact blades 54 by the individual coil springs 87.

As soon as front contact blades 54 are engaged by movable contact blades 60, they will be lifted off the upper side or surface of

partitions

68 and 71 of the front molded block 63 'and tend to further compress the associated coil springs 86. The pressure of the springs 86 is immediately effective to insure proper electrical contact between movable contactarme 60 and front contact arms 54. In addition, for reasons previously set forth, the exerted spring pressure of coil springs 86 remains substantially at the pressure preset by compressing them during assembly.

Referring to FIG. 2, a thin, accurately dimensioned sheet or plate 96 of suitable nonmagnetic material is attached to the upper side of the left-hand end 18 of the relay armature 16 and covers the working air gap of the relay. This plate 96 is provided to prevent the armature 16 from being stuck in its attracted position by any residual magnetism present in the relay magnetic structure, after the relay windings have been deenergized, to release the armature 16. The sheet 96 is retained in position by the spring seat which is rectangular in crosssection vand ts through a corresponding rectangular hole in the sheet 96. The plate 96 and the spring seat S5 are held by the pressure of the spring 82.

If the relay windings 15 are now deenergized, the combined loading pressures exerted by coil springs 86 and the coil spring 82 until front contacts 54 are disengaged are effective to cause the armature 16 to return to its normal released position, as shown, wherein it rests on sur'- face 81 of the front molded frame 63, and wherein mov* able contact blades are brought into engagement with back contact blades 54.

Referring to the diagram of FIG. 14, line represents the distance of travel of the portion 18 of the relay armature 16. Line 101 represents force. The solid line, generally referred to at 102 represents the load on the relay armature during its travel from the fully released position to the closed position. When the armature is fully released, the armature load is as represented at portion 103 of the solid line of 102. During travel of the armature 16 between points 103 and 1194 of line 102, the biasing force of the spring 82 which is decreased by the pressure of the springs 87 provides a load which remains substantially constant as is apparent from the slight slope of this portion of line 102. When the back contacts 54 open, the load on the armature increases abruptly to point 105 on the line 162 because the springs 87 no longer act to reduce the load. Between points 1115 and 106, the load remains substantially constant because of the low spring constant and the position of the spring 82 in substantial alignment with the air gap. When the front contacts 54 close, the armature load increases abruptly as represented by point 107 on line 102. This load remains substantially constant for the remainder of the armature travel because of the position and low spring constants of the springs 86 with the spring 82 now aiding the springs 86 in loading the armature. Thus, if because of manufacturing variations the travel of the armature is reduced slightly so that it is fully released at point 108 on the line 100, for example, the load on the armature remains substantially the same. Also even though the Contact elements 59 wear down after long and continued used, which would cause earlier disengagement with back contacts 54, and later engagement with front contacts 54, the loading pressure caused by these contacts 54, and the contact pressure remains practically the same. Solid line 110 of FIG. 14 represents the pull of the armature from its full released position to its fully picked up position. As seen from this diagram the slope of the pull curve 11@ is gradual which permits of a substantially wide variation in voltage range to effect the same operating characteristics and render the relay relatively insensitive to any small production variation.

The coil springs 82, 86 and 87 are all mounted in substantially vertical alignment with the working airgap of the relay close to the contact elements 59 and thus, the various predetermined pressures exerted by these coil springs accurately determine the loading pressures on the relay armature 16, and therefore also, the operating values of the relay as pointed out in connection with FIG. 14. It is apparent that the coil springs 82, S6 and 87 are removably mounted in the relay structure, so that different value coil springs may be inserted, for example, if it is desired to change the operating values of the relay, as is sometimes necessary if similar relays are to be utilized in more than one type of circuit arrangement.

In actual practice, it has been determined that a relay according to the present invention reliably operates solid state devices. This is believed primarily due to the relatively constant contact pressure over a generous compression distance. The initial contact is close to its selected Contact pressure and is relatively uniform throughout the entire range of contact travel. The short distance between the springs 8d, 87 and the contact 59 causes it to come up fast. Thus, there appears to be no contact bounce until after the armature and contacts have com pleted their travel, and the time for operating the solid state devices is sutiicient during the interim while the movable contacts are in engagement with the iixed contacts during armature travel.

Referring to FIG. 10, an alternative embodiment is illustrated wherein the contact blades referred to at 54 may be made to have integral lateral projections bent to form a at spring to provide the desired contact pressure. The flat spring 11S may be compressed sufficiently to provide characteristics similar to the coil springs 86 and S7 of the previously described embodiment.

FIG. 1l illustrates a further modification wherein liat springs such as 116 may be inserted in position in place of the coil springs 86 and 87. FIG. 12 illustrates a still further modiiication whereby a coil spring 117 may be insulatedly connected at one end to a plastic member 12) positioned in an opening of a front contact blade 54 and at its opposite end to a similar member 120 positioned in an opening of a back contact blade 54. The spring would be under sutlicient tension to provide the required loading pressure as described in the previous embodiments.

A relay constructed in accordane with the present invention is provided with two energizing coils 15, each of which is capable of operating the relay armature independently. Each of the windings 15 has a resistance in the order of 180 ohms and is adapted to be operated in the 12 to 30 volt range. Referring to the graph of FIG. 13, which represents the B/H curve of the relay, line represents the amount of magnetizing force in ampere turns H(NI) required to produce B kilo-lines per square inch of the flux density. It is apparent from FIG. 13 that when the armature is closed the magnetic circuit is saturated at approximately one hundred ten kilo-lines per square inch and the slope of line 125 is gradual from approximately three hundred ampere turns onward. The knee of the curve of line 125 commences at approximately one hundred ampere turns. The open air gap curve represented by line 126 illustrates that saturation occurs at slightly less tlux density than the closed air gap curve. The relay of the present invention picks up at point 127 on the curve 126 which is substantially in the saturation range of the curve 125. Once picked up the relay will stay up with a ux density as low as approximately eighty kilo-lines per square inch of force which is represented by point 128 on line 125. The armature drops away at point 130 which is approximately sixty kilo-lines per square inch. Because the relay operates in the area of saturation the ampere turns or force can vary considerably without causing an appreciable change in the ux density, and thus the pull on the armature. This, together with the large air gap area provides a flat pull curve that is insensitive to relatively minor voltage variations.

Having thus described a relay according to the invention with several modifications of the contact spring arrangement, it is understood that other modifications, particularly as regards the shapes of the component parts, as well as the arrangement of the Contact blades, may be made without departing from the spirit or scope of the present invention.

What I claim is:

1. A relay comprising, an elongated core substantially rectangular in cross-section,

(a) an energizable coil assembly mounted on said core and positioned to have a forward portion of the core extend outwardly of the coil;

(b) an armature hingedly connected adjacent one end of the core and disposed to have a forward portion of the armature attracted to the forward portion of the core upon energization of the coil;

(c) a frame of insulative material on the forward portion of the core having an internal dimension to receive the forward portions of the core and armature;

(d) said frame having inwardly extending integrally formed shoulders in engagement with the core to position precisely the frame on the core;

(e) means engaging the forward portion of the core and the frame to secure the frame in the precise position;

(f) said frame having a first integral cross member extending spaced from the core and engageable by the forward portion of the armature when the coil is deenergized to precisely x the travel of the armature;

(g) a plurality of movable contact blades insulatively attached adjacent said one end of the core and positioned to extend through the frame;

(h) an insulative card afixed to the armature and the opposite ends of said movable contact blades to precisely positionthe extending opposite ends of said movable contact blades relative to the armature;

(i) a plurality of fixed contact blades insulatively attached at said one end of the core and extending in vertical spaced alignment from the movable contact blades through said frame to be engaged and disengaged at their opposite ends by their associated movable blades in accordance with the operation of the armature;

(j) said frame also having other integral cross members each having a surface opposing that portion of each respective fixed contact blade in the frame and so positioned to limit the position of each fixed contact blade when disengaged by its aligned movable contact blade; and

(k) spring means positioned in the frame disposed to engage a portion of each fixed contact blade in aligned spaced relation to the forward portion of the core constantly urging each fixed contact blade toward said opposing surface of its respective cross member.

2. A relay as claimed in claim 1 wherein the forward portion of the core has a pair of recesses formed in opposite edges thereof and the integrally formed shoulders each have an integral extending portion to mate in the recesses when the core engages the shoulders of the frame.

3. A relay as claimed in claim 1 wherein the frame has an integrally formed interior surface spaced from the surface of the forward portion of the core opposite the armature and the means for securing the frame in precise position is an arcuate spring means positionally inserted when compressed between the forward portion of the core and the spaced interior surface.

4. An electromagnetic relay, comprising (a) a rectilinear magnetic core substantially rectangular `in cross section and having adjacent its rear end an irregular opening defined at its forward edge by a transverse wall;

(b) a coil `structure including a spool having a central rectangular opening positioned on said core with opposite ends of the core extending axially outwardly through the central opening;

(c) an armature rectangular in cross section and having adjacent one end at its side edges a pair of oppositely positioned notches having a length greater than the thickness of the core and of lsuch a depth that the distance between the inner edges of the notches is less than the length of the transverse wall at the forward edge of the irregular core opening;

(d) said armature being positioned in the irregular 14 core opening with the side of the core mating with the notches of the armature;

(e) the opposite end of the armature extending toward and beyond the forward end of the core;

(f) a pair of mating insulating members positioned on opposite sides of the core and having a portion extending into the irregular opening rearwardly of the armature;

(g) resilient means mounted intermediate its upper and lower surfaces in the front portion of the mated insulating members urging constantly the armature in contact with an edge of the transverse wall of said irregular opening;

(h) a plurality of insulative beds so congurated to mate with the upper and lower surfaces of the mated insulating members and with each other positioned in stacked relationship on the upper and lower surfaces of the insulating members;

(i) a plurality of elongated metallic contact blades positioned in precise alignment and fixed at one end between the stacked insulative beds;

(j) a molded grate-like structure attached to the extending forward end of the core with the free ends of the contact blades and the armature extending forwardly thereof through suitable openings provided therefor,

(k) first spring means mounted in the grate-like structure constantly urging the armature against an associated surface of the structure,

(l) second spring means mounted in the grate-like structure constantly urging certain of the contact blades against associated surfaces of the structure, and

(m) a card afiixed to the extending end of the armature and to others of the contact blades to cause such other contact blades to engage said certain contact blades when the coil windings are energized.

5. An electromagnetic relay as specified in claim 4 wherein said first and second spring means are coil springs which are removably mounted between the surfaces in said grate-like structure and said armature and said certain contact blades.

=6. An electromagnetic relay, comprising (a) a magnetic core;

(b) an energizing winding on said core;

(c) a back insulator member aflixed to one end of said core;

(d) an armature pivotally mounted on this end of said core and extending toward but spaced bya Working air gap from the opposite extending end of said core;

(e) said armature being attracted to or released from said core in accordance with the energization of said winding;

(f) a movable card mounted on the extending end of said armature;

(g) a plurality of contact blades each having one end fixed by said back insulator member and certain of which have their extending ends carried by said movable card to selectively engage the extending ends of those contact blades not carried by said movable card in accordance with the operating position of said armature;

(h) a front insulator member having registered surface means therein for respectively determining the position of the extending end of said core and the unengaged positions of the extending ends of those contact blades not carried by said movable card;

(i) first spring means operatively positioned in the 7. An electromagnetic relay as claimed in claim 6 wherein said back insulator member has a plurality of Contact slots formed therein for receiving one end of each of said plurality of contact blades, each of said contact slots having at least one surface thereof accurately registered to be parallel to a corresponding surface of the remaining contact slots, and said back insulator member including integral resilient projections for biasingV said contact blades against said accurately registered surfaces of said Contact slots when the contact blade-s are positioned therein.

S. An electromagnetic relay as claimed in claim 6 wherein said first and second spring means are positioned in substantial alignment with the Working air gap of the relay rearwardly of the card.

9. An electromagnetic relay as claimed in claim 6 wherein said iirst and second spring means are low rate coil springs.

10. An electromagnetic relay as claimed in claim 6 wherein said second spring means for biasing the contact blades are low rate flat springs.

11. A relay as claimed in claim 6 wherein said front insulator member includes a further registered surface means therein for determining the released position of said armature, and wherein said iirst and second spring means are coil springs in a compressed condition respectively positioned to engage said armature and the respective Contact blades not carried by the card, and said coil springs also engaging the spaced opposing surfaces of the front insulator member.

i2. A relay as claimed in claim 6 wherein said contact blades not carried by the card are positioned in spaced alignment, and the second spring means for biasing the aligned contact blades is a coil spring insulatively connected at opposite ends under tension between said aligned contact blades.

13. rThe relay according to claim 6 wherein the amount of deection of said first and second spring means in placing them in their assembled positions is relatively large compared to the amount of deflection of said iirst and second spring means during operation of said armature.

14. In a relay,

(a) a core having a cut out portion at one end thereof forming a transverse edge in said core spaced from said one end of said core,

(b) an armature mounted in said cut out portion to pivot about an axis substantially parallel to said transverse edge and extending toward but spaced by a working air gap from the opposite end of said core,

(c) an insulative member positioned and formed to iixedly engage said one end of said ocre and having a portion extending into said cut out portion of said core to retain said armature in operative position; and

(d) resilient means mounted between said armature and said insulator member to constantly urge said armature into engagement with the transverse edge of the core.

l5. In a relay,

(a) an armature operatively mounted at one end with .its free extending end movable to opposite limit positions, said armature having a hole therein adjacent its free extending end,

(b) a plurality of contact blades each having one end -xed and the other end extending substantially parallel with said armature, certain of said contact blades being movable to selectively engage others of said contact blades in accordance with the position of said armature, each of said movable contact blades having a transverse slot therein adjacent its extending end, and

(c) a card of insulation having openings therein to receive ttingly the extending end of said armature and the extending ends of said movable Contact blades and having a resilient integral hooked projection te therein normally projecting yieldingly into that opening which receives said armature and positioned to engage in said hole in said armature when said card is fitted into said transverse slots in said movable Contact blades.

16. An article of manufacture adapted to be secured to the core of .a relay for precisely positioning the release position of the armature and the fixed contact blades of the relay, comprising,

(a) a molded frame of insulative material of suflicient internal lateral dimension to receive a relay core; (b) a pair of integrally formed oppositely disposed shoulders in the interior of the frame to be engaged by the relay core to position the frame precisely relative to the core;

(c) a first integrally formed member, one surface of which is precisely positioned from said shoulders and disposed to be engaged by the armature in its released position; and

(d) a plurality of second integrally formed members, each having one surface precisely positioned from said shoulders and from each other against which the fixed contact blades of the relay engage when released.

17. In a relay structure,

(a) a plurality of fixed and movable contact blades each insulatedly supported at one end, and the fixed contact blades of which have their free ends relatively located for engagement by saidv movable Contact blades whose free ends are moved in accordance with the operation of a relay armature,

(b) a frame having a plurality of registering surface means to determine the unengaged positions of the free ends of said xed contact blades and other surface means disposed opposing said registering surface means and spaced therefrom by a predetermined distance,

(c) spring means located between each of said opposing surfaces means and an associated one of said fixed contact blades for continually urging that contact blade toward its registering surface means,

(d) said spring means having a normal non-deflected length greatly in excess of said predetermined distance between said registering surface means and said opposing surface means in said frame,

(e) whereby the amount of detiection of said spring means by its location is much greater than the amount of deliection of said spring means during relay operation, and

(f) whereby said spring means exerts a substantially constant biasing force on the associated fixed contact blade during operation of the associated movable Contact blade and regardless of contact wear during such operations.

18. An electromagnetic relay comprising,

(a) a generally flat rectangular core having notches at both sides thereof adjacent one end,

(b) a front insulator block having shoulders thereon to mate with the notches on said core,

(c) first resilient means compressibly mounted between said core and an opposing surface on said insulator member for continuously biasing said core against said shoulders in assembled position,

(d) said core having a cut out portion at its opposite end to form a transverse edge in said core spaced from said opposite end,

(e) an armature mounted in said cut out portion to pivot about said transverse edge,

(f) a back insulator block fixedly mounted on the cut out end of said core and having an extending portion which extends into the cut out portion of said core to retain said armature in assembled position Within said cut out portion,

g) an energizing winding interposed on said core be- .tween said front and back insulator blocks.

(h) second resilient means compressibly mounted between said armature and the extending portion of said back insulator block for continuously biasing said armature against the transverse pivoting edge of said core,

(i) a plurality of insulator members mounted in stacked relationship on said back insulator block and carrying a plurality of contact fingers which extend through openings in the front insulator block,

(j) anchoring means for holding the back insulator block and said insulator members in stacked relationship,

(k) a card carried on the extending end of said armature and effective to carry certain of said contact -iingers into engagement with the others of said contact fingers not carried by said card,

(l) a plurality of surfaces on said front insulator block formed to x the released position of said armature and the respective unengaged positions of those contact ngers not carried by said card,

(m) third resilient means compressibly mounted between said armature and an opposing surface of said front insulator block to constantly bias said armature toward its released position, and

(n) fourth resilient means compressibly mounted between those contact fingers not carried by said card and opposing surfaces on said front insulator block to constantly bias those contact ngers not carried by said card toward their respective unengaged posi- 5 tions.

References Cited bythe Examiner UNITED STATES PATENTS ROBERT K. SCHAEFER, Acting Primary Examiner.

25 BERNARD A. GILHEANY, Examiner.

Claims

1. A REALY COMPRISING, AN ELONGATED CORE SUBSTANTIALLY RECTANGULAR IN CROSS-SECTION (A) AN ENERGIZABLE COIL ASSEMBLY MOUNTED ON SAID CORE AND POSITION TO HAVE A FORWARD PORTION OF THE CORE EXTEND OUTWARDLY OF THE COIL; (B) AN ARMATURE HINGEDLY CONNECTED ADJACENT ONE END OF THE CORE AND DISPOSED TO HAVE A FORWARD PORTION OF THE ARMATURE ATTRACTED TO THE FORWARD PORTION OF THE CORE UPON ENERGIZATION OF THE COIL; (C) A FRAME OF INSULATIVE MATERIAL ON THE FORWARD PORTION OF THE CORE HAVING AN INTERNAL DIMENSION TO RECEIVE THE FORWARD PORTION OF THE CORE AND ARMATURE; (D) SAID FRAME HAVING INWARDLY EXTENDING INTEGRALLY FORMED SHOULDERS IN ENGAGEMENT WITH THE CORE TO POSITION PRECISELY THE FRAME ON THE CORE; (E) M EANS ENGAGING THE FORWARD PORTION OIF THE CORE AND THE FRAME TO SECURE THE FRAME IN THE PRECISE POSITION; (F) SAID FRAME HAVING A FIRST INTEGRAL CROSS MEMBER EXTENDING SPACED FROM THE CORE AND ENGAGEBLE THE THE FORWARD PORTION OF THE ARMATURE WHEN THE COIL IS DEENERGIZED TO PRECISELY FIX THE TRAVEL OF THE ARMATURE; (G) A PLURALITY OF MOVALBE CONTACT BLADES INSULATIVELY ATTACHED ADJACENT SAID ONE END OF THE CORE AND POSITIONED TO EXTEND THROUGH THE FRAME; (H) AN INSULATIVE CARD AFFIXED TO THE ARMATURE AND THE OPPOSIT ENDS OF SAID MOVABLE CONTACT BLADES TO PRECISELY POSITION THE EXTENDING OPPOSITE ENDS OF SAID MOVABLE CONTACT BLADES RELATIVE TO THE ARMATURE; (I) A PLURALITY OF FIXED CONTACT BLADES INSULATIVELY ATTACHED AT SAID ONE END OF THE CORE AND EXTENDING IN VERTICAL SPACED ALIGNMENT FROM THE MOVABLE CONTACT BLADES THROUGH SAID FRAME TO BE ENGAGED AND DISENGAGED AT THEIR OPPOSITE ENDS BY THEIR ASSOCIATE MOVABLE BLADES IN ACCORDANCE WITH THE OPERATION TION OF THE ARMATURE; (J) SAID FRAME ALSO HAVING OTHER INTEGRAL CROSS MEMBERS EACH HAVING A SURFACE OPPOSITE THAT PORTION OF EACH RESPECTIVE FIXED CONTACT BLADE IN THE SO POSITIONED TO LIMIT THE POSITION OF EACH FIXED CONTACT BLADE WHEN DISENGAGED BY ITS ALIGNED MOVABLE CONTACT BLADE; AND (K) SPRING MEANS POSITION IN THE FRAME DISPOSED TO ENGAGE A PORTION OF EACH FIXED CONTACT BLADE IN ALIGNED SPACED RELATION TO THE FORWARD PORTION OF THE CORE CONSTANTLY URGING EACH FIXED CONTACT BLADE TOWARD SAID OPPOSITE SURFACT OF ITS RESPECTIVE CROSS MEMBER.