US2686850A - General purpose relay - Google Patents

Description

Aug. 17, 1954 E. L. EARLE 2,686,850 GENERAL PURPOSE RELAY Filed Oct. 26, 1950 INVENTOR EDWIN L.. EARLE ATTORNEY Patented Aug. 17, 1954 2,686,850

UNITED STATES PATENT OFFICE 2,686,850 GENERAL PURPOSE RELAY Edwin L. Earle, Chicago, 111., assignor, by mesne assignments, to International Telephone and Telegraph Corporation, a corporation of Mary land Application October 26, 1950, Serial No. 192,260

2 Claims. 1

This invention relates to electro-magnetic relays and more particularly, general-purpose electromagnetic relays of the type used in the telephone communication industry.

This invention is a direct improvement on the relay apparatus disclosed in the application of Arthur et a1. Serial No. 20,196, filed April 10, 1948.

A general object of this invention is to provide reliable and economically produced relays suitable for meeting a large number of varying switching requirements.

A specific object is to provide a new and improved structure which facilitates alignment of the armature keeper.

A further specific object is to provide a relay structure of the foregoing character in which the number of actuating ladders required to meet the large variety of switching needs is minimized.

In the relay construction to which this invention is directed, insulated ladder-type switch actuating members are associated with spring sets stacked in a sequence according to the number of spring members contained in the stack, whereby the diiferent ladder forms may be limited to a minimum number. After the limited minimum number of ladder shapes is determined, this invention effects a further reduction in ladder forms by providing a double row of steps oppositely disposed on the edges of the same ladder, each row accommodating a specifically different combination of spring-set sequences. This arrangement makes it possible to cut in half the number of standard ladder configurations required for the noted system of stacking.

To assure proper aligned association of the armature of the relay with the spring stack, a raised portion is provided on the upper surface of the magnetic support plate for cooperation with a slot provided in the armature keeper, and with the mounting screw which extends through the keeper slot, so as to properly align the keeper, which in turn, properly aligns the armature with the switch stack. A resulting feature is that the armature alignment with the switch assembly is predetermined and automatically accomplished incidentally to assembly of the relay.

Other objects and features will appear as the description progresses.

Fig. 1 is a top plan view of a relay embodying the invention shown with a portion of one upper back contact spring of the switch assembly broken away to reveal the shape of the uppermost front contact spring as representative of the shape of the remaining front contact springs.

Fig. 2 is a side elevational view of the relay of Fig. 1.

Fig. 3 is a top plan View of the relay with its switch assembly removed.

Fig. 4 is a front elevational View of the relay shown in Fig. 3 with its armature assembly removed.

General structur e Referring particularly to Figs. 1 and 2, the relay includes an electromagnet I0, its armature II, a twin stack switch assembly I2 both stacks of which are actuable by the electromagnet through the armature, and an L-shaped return plate I3 on which the switch assembly and armature are mounted.

The electromagnet I0 includes a coil I4 and a cylindrical magnetic core I6 extending therethrough. The rear end of the core is threadedly received within an opening in the vertical portion of the return plate I 3, rendering it longitudinally adjustable. A locknut I1 is provided to retain the core in a desired longitudinal position of adjustment.

The electromagnet I0 has a rounded front spoolhead I8 fiat on its upper edge, and a square rear spoolhead I9 which may be seen in profile in Fig. 4. The fiat edges of the spoolheads retain this coil against rotation by reason of the squared relation of one edge of each with the under surface of the horizontal portion of the return plate I3.

Rcarwardly extending winding terminals 20 for coil I4 are located in a row along the lower edge of the rear spoolhead I9. The upstanding base portions of the terminals are kept out of engagement with the vertical rear portion of the return plate I3 by an insulating spacing collar 2|, which encircles the core I6 between the return plate I3 and the spoolhead I9.

The coil is retained in its longitudinal position at the front of the electromagnet by a spring clip 22 engaged within an annular groove in the front portion of the core.

As shown in Figs. 1, 2 and 3, the armature is held in position at the front of return plate I3 by a keeper-member 23. The keeper-member 23 is provided with a pair of arms 24 preferably disposed, as shown in Fig. 2, so that they make about equal angles with parts 26 and 27 which comprise the angularly disposed arms of the bellcrank armature I I. The smooth working surfaces of such arms bear against the bent portion of armature I I to prevent its upward or forward displacement.

To enable th keeper-member 23 and armature to be mounted on the return plate, an aperture or cut-out portion is provided in the arm 2% of armature H through which a flat bifurcated extending portion 28 of the keeper may be fastened to the return plate H3. The bifurcated extension portion comprises a pair of arms 2S3 defining a slot within which a fastening screw 38 is snugly accommodated for threaded ngagement with a hole in the top of the return plate is so that the arms 29 can be either tightened against the. return plate or slidably disengaged from the return plate upon loosening the screw 3%.

A raised cylindrical projection 31 is formed on the upper surface of the return plate just behind the screw as and underlying the front part of the switch assembly by a semi-perforating operation on the under side of the return plate. The raised portion 3! cooperates with the slot in the armature keeper to key it against rotation while the retaining screw 30 is being tightened in place. Besides keying the keeper against rotation the raised portion 3! is also used as a guide to locate the keeper in proper position for association with the armature ii. That is, while the keeper 23 is being mounted, the screw so and the raised perforation Bl both act to automatically align the keeper laterally by reason of their fixed location one behind the other on the return plate l3. and their snug fit within the slot formed in the keeper extension 28 by the arms 29. The length of the slot may be made such that the keeper can be longitudinally positioned by merely sliding it rearwardly until the end of the slot hits the screw 30. With such an arrangement, mounting and removal of the keeper and armature may be effected without complete removal of the screw 30, and both parts may be mounted on the return plate without the need for special lateral or longitudinal aligning procedures.

In its deenergized state, stop position of the armature is regulated by the setting of the screw 33 in the keeper-member 23, while a locknut 34 associated therewith locks the screw 33 in a desired position. A U-shaped residual plate 35, shown in Fig. 2, is applied to the armature and then crimped in place to ap pear as shown. Such plate, when employed, lies between the core and the armature. By striking the core, it holds the. armature out of contact therewith to insure that a desired amount of operating air gap remains unclosed with the armature in fully operated position. This is commonly referred to as the-residual gap which has a length determined by the thickness of plate 35, and controls the release characteristic of the relay, as is commonly known.

Switch assembly The twin stack switch assembly of Figs. 1, 2, and includes a cap-plate 3?, base plate 38, and parts clamped between them by screws M) which pass through openings in the cap-plate andintervening parts to the base plate, wherein they are threadedly received. Two opposed columns 42 and 43 of the contact sets are included in the same unitary assembly l2. This construction enhances rigidity and reduces the number of assembly and clamping screws required. The switch assembly is readily installed in position on return plate l3 and is simply secured by two mounting screws fill which pass through the assembly for threaded engagement with apertures Ala in the upper surface of the return plate. The switch assembly lies fiatly upon the return plate with the protruding ends of clamping screws the normal or back 40 thereof being received in provided clearance openings 49a in the return plate.

Referring now to Fig. 5 wherein the left hand column 43 is shown in profile to include four commonly denoted types of contact sets, the make-before-break set (fixed blade 44 and traveling blades 25 and 56) the break-make set (fixed blades 48 and 5t and traveling blade 49), the break set (fixed blade 5! and traveling blade 52), and the make set (fixed blade 55 and traveling blade 54) A spacing member 53 having the same thickness as the traveling blades, is used in the tongue portion of the assembly between the traveling blades 52 and 54, to balance the assembly by compensating for the travel or motion of the adjacent traveling blades. The right hand column may or may not include similar sets.

The traveling blades of both columns are moved by a pair of similar actuating ladders .53 which move the blades into and out of electrical contact with the fixed blades of their respective contact setsin response to movement of the associated armature. The ladder 58 which is provided for column 42 is actuated simultaneously with the ladder 58 of column 43 by the armature. Each of the contact blades of columns $2 and 43 has a terminal portion 6!] for the attachment of cir cuit wires. The terminals are staggered as shown in Fig. 1 for wiring convenience.

The traveling blades d6, 39, and 52 of the normally closed contacts in column 43 are downwardly tensioned by a preforming operation, and in normal position exert sufiicient contact pressure against their respective fixed contact blades 44, 48, and El to insure that reliable electrical connection is established therebetween. The traveling blades 15, and 54 of the normally open contacts of each column are slightly tensioned downwardly to insure that they will return to their normal open position after operation.

The fixed blades are sufficiently rigid to withstand pressure exerted against them by their respective traveling blades and are all of similar construction with th exception of fixed blade M, which is upwardly offset at the front. Blade 44 is constructed in this manner to permit its associated make-before-break contact set to perform its usual functions with the actuating blade 5 thereof in an intermediate position between blades 44 and it, which places the control thereof at the same point or level as that of the breakmake sets. It is important to have control of the different sets thus fixed at the same level since they can then be actuated by the same step on the actuating ladder 53, making it possible for the two sets to be interchangeable and thereby promoting adaptability to operation of a number of switches comprising different contact set combinations with a minimum number of actuating ladders.

Each actuating ladder 5B is operatively associated with its respective switch stackup by being passed through a series of aligned slots comprising one slot in each traveling blade and then placing its steps in en agement with the respective blades which it is to acuate. The ladder slots are somewhat longer than the width of the ladder which they accommodate so that the ladder may be readily passed through them.

To secure each of the ladders 58 in a vertical position in engagement with their traveling blades, a pair of retaining springs 2'6 and H are provided at the bottom and top of each stack respectively. A narrow elongated aperture is provided in each retaining spring to permit the spring to snugly accommodate an end of the ladder of its stackup. The upper retaining spring the return plate l3.

Numerous combinations of contact sets are possible in switch assemblies of this type; and for this reason a large number of actuating ladder forms are usually required to accommodate all the possible combinations. As pointed out above, the number of actuating ladder forms may be reduced somewhat by arranging some of the contact sets so that fewer step shapes and spacing arrangements are required. To further reduce the number of ladder forms to meet all switch combinations, steps are provided along both longitudinal edges of the ladder, thus making it possible to adapt the ladder to substantially double the number of arrangements of contact sets. This may be readily seen by viewing Fig. 6 in which the actuating ladder 58, which was used spect to its position in Fig. 5 so that the steps along the edge opposite that used in the stackup of Fig. 5 can be used with the second switch assembly. For more ready comparison, the ladder 58 is also shown in Figs. 7 and 8 in the positions in which it is used in the assemblies of Figs. 5 and 6.

The assembly of Fig. 6 includes five contact sets, the break-make set (fixed blades 5! and 63 and traveling blade 62) the two break sets (fixed blades 65 and 68 respectively, and traveling blades 66 and 69 respectively), spacer member 6'! and two make sets (fixed blades 72 and I4 and traveling blades TI and T2). The steps along the second edge of ladder 58 are spaced so that they will fit in engagement with the traveling blades of this switch assembly. The ladder is thereby made capable of fitting two entirely different switch assembly arrangements which have no relation whatsoever as far as their sequence of stacking contact sets is concerned. Thus, it is readily apparent that the number of standard froms of actuating ladders which might normally be required with single sided ladders can be effectively cut in half by providing ladders having steps along two edges thereof. practice, where twenty-one ladder forms might satisfactorily meet all combinations of contact sets normally encountered, the use of double sided ladders will permit this number to be cut to eleven ladder forms.

To enable an end for end reversal of the double sided ladder 58 so that both rows of steps can be associated with contacts in different assemblies, a pair of projections are provided at each end of the ladder; one of which is primarily a foot portion and a means for securing the ladder when it is disposed at the bottom of the ladder; and

the other, a somewhat shorter and narrower portion which engages the armature for actuation of the switch assembly when disposed at the bottom of the ladder, and as a means for retaining the ladder when located at the top. As shown in Fig. 5, the foot projection 78 at the bottom of the ladder is engaged within an aperture in the lower ladder retaining spring 16, and in passing through the aperture it comes into contact with the upper surface of the return plate I 3 upon which it rests. The aperture in the retaining spring 16 is of just the right size to permit the width of the foot projection 18 to fit therein For example, in

' posed at the bottom of the ladder.

snugly without play, thereby holding the bottom part of the ladder in position. The shorter projection 79, as shown in Fig. 5, is disposed immediately in front of the foot projection 18, and by reason of its shorter dimension, the arm 26 of the armature l I can be slipped thereunder for operative association with the ladder. The projection 19 is made sufficiently short so that a large enough clearance exists for the end of arm 26 of the armature to be inserted under the projection without disturbing or upsetting the ladder or switch assembly after the assembly is mounted on the return plate I3. Once the arm 26 is positioned in underlying relation to the forward engaging projection 19, the normal back position of the armature is obtained by turning the backstop screw 33 inward until contact is made by the arm 26 with the projection 19 without lifting the ladder.

Fig. 5 also shows that the second foot projection and the shorter projection 81 at the top of the ladder are disposed in reverse order to that in which the corresponding projections are dis- That is, the shorter projection 81 at the bottom of the ladder is disposed behind the foot projection. The ladder retaining Spring 11 this is conveniently positioned to engage the armature engaging projection Hi to hold the upper part of the ladder in place. The aperture in the retaining spring 11 thus need not be as large as that in the retaining spring I6 since the projections accommodated therein are of narrower width. By reason of the difference in size of the apertures in the retaining springs, the ladder 58 can be oriented with the switch assemblies in only two ways rather than four which would be possible if both projections at each end of the ladder could be inserted in the apertures of either of the retaining springs l6 and 11. That is, when the foot projection 18 is located at the bottom of the ladder, the ladder can be mounted in the retaining spring only in the manner shown in Fig. 5, and cannot be turned so that its front edge faces the rear, because the foot projection 89 at the top of the ladder will not fit within the aperture in the top retaining spring Tl. Correspondingly, when the foot projection 8D is located at the bottom of the ladder, as in Fig. 6, only one edge can be made to engage the traveling springs of the switch assembly while being held by the retaining springs, because the foot projection 18 at the top of the ladder cannot be inserted in the aperture of the retaining spring Tl.

As indicated, the retaining spring 11 is tensioned downwardly to assist in biasing the ladder 58 downwardly against the return plate [3. In this respect, it is to be noted that the cut-out portion between the projections 89 and 8!, engaged by the retaining spring TE, as shown in Fig. 5, is somewhat deeper than the cut-out portion between projections 18 and T9 at the bottom of the ladder. The diiference in depth of these two cut-out portions exists by reason of the fact that the two switch assemblies for which the ladder is designed each have a different over-al1 height and the difference exists in order to make the retaining spring 77 provide the same biasing force for the switch assemblies of both Figs. 5 and 6. The depth of the cut-out portion between projections 80 and iii, within which the biasing spring ll engages for the assembly of Fig. 5, must therefore be greater than the depth of the cutout portion between projections 18 and 19 engaged by the spring 17 for the assembly of Fig. 6 which has a greater over-all height.

As shown in Figs. 7 and 8, the steps provided along the edges of the ladder 58 are formed by cut-out portions or notches N! through N9 in the edges which leave the steps as projections for engagement with the traveling springs. The notches are of such width that sufficient space is provided above the engaging edges of the steps that association of the ladder in proper position for engagement with the traveling springs of the respective assemblies is easily accomplished. The distance between adjacent notches and the distance between each notch and the foot located directly below is dependent upon the type of contact sets with which the traveling springs are associated. In this respect, it will be noted that the distance between each foot of ladder 58 and the first moving contact blade with which the foot is actively associated in the difierent switch assemblies (the distance from tip of foot 78 to notch Ni and the distance from the tip of foot 89 to notch N9) is the same. Similarly the distance from the foot and the second moving contact blade (the distance from the tip of foot 78 to N2 and the distance from the tip of foot 89 to N8) in each assembly is the same. From the second step on up, however, it will be noted that difierent distances exist between the moving blades and the ladder foot, since the third contact set in Fig. is disposed above a set having three springs (the third or upper spring being a stationary spring), while in Fig. 6 the third contact set is disposed above a set comprising only two springs. The distance between the second and third notches in the assembly of Fig. 6 (N8 and N1 in Figs. 7 and 8) therefore is not required to be as large as the distance between corresponding notches (N2 and N3 in Figs. 7 and 8) in the ladder for the switch assembly of Fig. 5. Subsequent adjacent notches (N3 and and N1, N6, and N5 in Figs. 7 and 8) in each of the assemblies are more closely spaced because they are associated with contact sets comprising only two springs. The assembly of Fig. 5 must of necessity be limited to a smaller number of sets within a given height because the contact sets at its lower level include a greater number of springs and consequently occupy a greater portion of the over-all height.

In the light of the above description, it is apparent that the ladder incorporated in the switch assembly, in being adapted to actuation of more than one stack or combination of contact sets, greatly reduces the number of standard actuating ladder forms required to meet the combinations that might be encountered in practice. In addition, it is readily seen that adjustment of the switch assemblies may be accomplished before they are mounted on the return plate of the relay. Still further, adjustment of the contact sets may be effected even after the assembly is mounted on the return plate 13, independently of the association of the assembly with the armature. In other words, after the switch assembly is mounted on the return plate and the ladder is biased downwardly on the upper surface thereof, each of the contact springs in the assembly may be adjusted for tension by bending them for the desired biasing effect even before the armature is put in place on the magnetic structure of the relay. After such adjustment is accomplished, the armature may be slipped in place and mounted on the relay without disturbing the switch in any manner whatsoever. As pointed out above, the armature is then adjusted so that its backstop position is such that its arm 28 just contacts either projection 79 or 8! respectively, without lifting the ladder.

Upon'energization of the electromagnet I0, the associated armature H turns about its axis to bring its lower attracted'portion 27 into contact with the dome end of the core 16 which provides an adjustable front stop for the armature.

Upon deenergization of the electromagnet, the downward tension, of the associated traveling blades of the switch assembly serve to turn the armature to its normal position, and as indicated, the normal or back stop position of the armature is regulated by the setting of screw 33. Turning the screw in the opposite direction permits a more expanded return movement of the armature. Locknut 27, when tightened, locks screw 26 in the desired position which in many instances will be dependent upon the residual gap which will provide the operatingtiming desired.

I claim:

1. An actuating ladder for electrical switching assemblies including contact sets spaced apart in a stackup, said ladder comprising a striplike member having its edges serrate to provide two rows of actuating steps disposed respectively on opposite sides of the member, one row having the steps thereof spaced from each other difierently from those of the other row, thereby adapting it for operative association with a stackup of contact sets spaced apart different- 13 from those with which the other row may be operatively associated, said strip-like member having opposite ends of which a portion has a lesser length than the overall length of the member, either longer end portion defining a stop and either lesser end portion defining a means tobe engaged by an operating member.

2. In an electrical switching device comprising a switch assembly of stacked contact sets, means including a plate-like base for supporting said assembly, a switch actuating ladder comprising a strip-like member having serrations providing separate actuating steps for said contact sets respectively, means for holding said ladder with its steps in operative association with said contact sets, means included in said switch assembly biasing said contact sets downwardly to a non-operated position, means including an operating member movably supported on said base for applying force for upward movement of said ladder against said biasing means to a position of operation, said strip-like member having a longer and a shorter lower end portion defining respectively a stop on said base and an abutment to be engaged by said operating member.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,997,655 Sanford et al Apr. 16, 1935 2,069,171 Merkel Jan. 26, 1937 2,077,091 Brander Apr. 13, 1937 2,120,980 Johnston June 21, 1938 2,190,381 Merkel Feb. 13, 194.0 2,282,687 Vigren et al May 12, 1942 2,426,253 Towner e Aug. 26, 1947 2,488,669 Knos Nov. 22, 1949 2,566,840 Krumreich Sept. 4, 1951 2,602,867 Vincent July 8, 1952 2,616,993 Koehler Nov. 4, 1952 2,632,065 Smith et al Mar. 17', 1953

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