US2550578A - Relay construction - Google Patents

Description

l 'aten ted Apr. 24,

U N I TED STATE PAT EN T OF Fl CE 2,550,578 7 RELAY coNs'rRU'rioN Robert K. McBerty, Galion, Ohio, :assignor "to The North lllcctric Manufacturing Company,

Galion, Ohio, a "corporation of Ohio Appucaiio'n aya), 1946, SerialNo.-d73,195

'2 Claims. (01. 200-87) over the relay construction disclosed in the 'co-' pending application of Frank R. 'McBerty, Serial No. 652,335, filed March- 6, 1946 and assig ne'd'to the assignee of this application. 7

The relay construction, to which the present invention relates,-comprises a plurality-ofmetallic reeds of stainless steel which are stationarily mounted near one end and are arranged to be flexed by electromagnetic means attracting an elongated armature carried near the free end thereof. Generally a number of 'reeds is em ployed for each relay, the number depending upon the circuitconnectionsthat are to be controlled. Of course, a single reed and armature can be employed.

Since the voltage applied to telephone circuits is relatively low, only aslight movement of the reed and armature is required for opening or closing a circuit. Because'of this slight'movemerit-particular care is-taken to limit the movement of the reed-and armature 'awayffromthe cooperating electromagnetic means and stationary contact. For this purpose a back stop in the'form'ofa round glass rod has been us'ed. This rod has been positioned transversely'of the reeds and the construction thereof 'Wlth respect .to the 'mounting of the armature thereon has been such that the armature, which is formed of -relatively soft magnetic 'material such as a nickel iron alloy, has been allowed "to engage :the back stop. After repeated operations of therelay and a corresponding 'number'of engagements of the armature or armatures with theback stop, ithas beenfoun'dthatthe-arma ture,-because of its being formed of relatively soft metal tends to wear away and "produce a fine metaldust-on the backstop. IILthGjPIZQS- ence of -moisture this dust has adhesive characteristics such that-the armature tends to stick to the back stop, in certain circumstances and theattractive force applicable tothe-armature by the electromagnetic means is not sufli'cient to.pull the same-away arid operate the contact Inthe-copendingapplication of Frank R. Mc- Berty,above referred to, this difficulty was over come :by positioning the reed in a longitudinal slotfalongoneiside of:the armature with the reed extending slightly above" thesurface of the'arm'a ture. The armature was then deformed to cause the sides of the slot to grip' the reed =therebetween and then the reed was spot welded to the armature. The portion of the reed extend-'- ing from the surface of the armature [was per mitted to engagethe'glass rod back stop. In this manner the wearing away of the armature was prevented .since substantially only point contact engagement was present'between the relatively ,hard round metallic reed and the round glassrod back stop. 'The :present'i'nventijon ac? 'complish'es this same result in asomewhat more expeditious and satisfactory manner. I

The object of myinven'tion, generally stated,

is to provide a telephonerelay type of contact construction which shall be simple, efficient and long lived in operation and which ,may be readily and economically manufactured.

Another object is to secure an armature to ametallic reed to form a telephone relay type of contactfinger so as "to provide substantiall point contact engagement betweenthe reed and a back stop while the major portion of the reed coextensive with the armature is positioned below its "surface. a H

Another object is to simultaneously deform a-portion of the armature substantially around the metallic reed while relieving another portion of "the armature alongthereed'so that the latter will project slightly from the former to permit contact engagement with aback stop solely by the relatively hard metallic re'efd.

Other objects of-my invention will, in part, be obvious and in part appear hereinafter.

My invention is disclosed in the embodiment thereof shown in the accompanying drawing and it comprises thefeatures of construction and arrangement "of "parts which will be exemplified in" the construction hereinafter set .forth. and the scope of the application of which willbe indicatedin the appended'claiins. H a a For a morecomplete understanding of the nature and scope of my invention reierence'can be had to the "following detailed description taken in connection ,with 'the accompanying drawing, in which; I

Figure 1 is a view, partly in end elevation and partly-in section, showing a tens -relay1in which my invention is incorporated; a

Figure '2 is a view, at an enlarged scale; side "elevation of one of the-metallic reeds with its armature mounted adjacent 1 the cooperating stationary contact ofthe relayshown in'l 'igure 1. FigureB isa viewygpatrtl in sideelevation and partly insectiori, of-the upper portion of the reed carrying the arainture and-the stationary contact shown in Figurez;

Figure 4 is a perspective view of a portion of the armature, showing how it is relieved to expose a portion of the reed for contact engagement with the back stop; and

Figure is a detail sectional view, taken along the lines 55 of Figure 4.

Referring now particularly to Figure 1 of the drawing, it will be observed that the reference character l3 designates, generally, a relay, such as a tens relay, in which the present invention may be incorporated. It will be understood that this particular relay is shown merely for illustrative purposes and that the invention can be used in other relays to solve the problem of sticking of the contact fingers to the back stop which has been described in detail hereinbefore.

The relay comprises electromagnetic means including a coil ll disposed on a core I2 which extends upwardly from a back bar I3 and along the sides of which side plates I4 and I5 extend toward a pole piece [6 which is carried by the upper end of the core I2. As set forth in the copending application of Frank R. McBerty, above referred to, the back bar [3 supports a plurality of tens relays which together make up a link that forms a part of an all relay telephone exchange system.

Mounted on the pole piece 16 is a block 2i of insulation of a character which can be molded readily about stationary contact members 22 that extend upwardly therefrom to various heights to permit paralleling with similar contact members of other relays. Each contact member 22, which is preferably formed of German silver, has a reentrant portion 22 extending, as shown in Figure 3, into the block 2| of insulation to facilitate molding and holding the same in place. At its lower end the contact finger 22 is provided with an insert 23 of wear resisting metal, such as a gold alloy, which has a centrally located groove 24 to permit double contact engagement therewith by a transverse erosion resisting contact member 25 which may also be a gold alloy. The contact member 25 is carried at the upper end of an armature, shown generally at 26 on the side thereof adjacent the insert 23. When the armature 26 is attracted, as by energization of the coil I l it will be understood that it moves toward the stationary contact 22 and carries the contact member 25 therewith into contact engagement with the insert 23. The armature 26 is preferably formed of a nickel-iron alloy which provides the desired magnetic characteristics.

The armature 26 is mounted on the upper end of a flexible metallic reed 2! which is preferably formed of stainless steel. The reed 2'! is flattened, as indicated at 28 in Figure 2, intermediate its ends to facilitate its being molded and held in place in strip 29 of suitable insulating material, it being understood that each strip 29 has molded therein a number of the reeds 21, the number depending upon the type and character of the relay employed. Connection to the metallic reed 27 is provided at the lower end thereof which projects below the strip 29. As indicated in Figure 1, the strips 29 carrying the reeds 21 may be held in place along the back bar l3 by suitable screws 33.

The metallic reed 27 is so arranged and positioned with respect to the stationary contact member 22 that its inherent resiliency tends to bias it away therefrom. Ror proper operation of the several movable contact fingers making up the relay If), it is essential that the armatures 26 and reeds 21 supporting the same be uniformly spaced away from the pole piece N1 of the elecreceive the reed 21.

tromagnetic means. For this purpose a back stop 34 in the form of a glass rod is mounted transversely of the contact fingers and, as shown in Figures 1 and 3, is located along the upper ends thereof. As indicated hereinbefore, when the armature 26 has been so constructed that it, rather than the reed 2l, engaged the back stop 34, substantial wear of the armature took place resulting in the deposition of fine metallic powder on the back stop 34. This tended to cause sticking of the armature 26 to the back stop 34.

' Now, in accordance with my invention, as herein disclosed, I have provided a simple and effective way for mounting the armature 26 on the metallic reed 27 so that the latter rather than the former provides the sole contact engagement with the back stop 34.

This construction is shown more clearly in Figures 4 and 5 of the drawings. As there shown, the armature 26 has a longitudinally extending groove 35 along one side thereof. The groove 35 is centrally located and is of sufiicient width to In order to hold the armature 26 in place on the reed 2? and to provide good mechanical and electrical engagement therebetween, the armature 26, with the reed 2'! in place in the groove 35, is positioned in a suitable die of a press where Sllfi'lClBllt pressure can be applied to the opposite sides 36 of the armature 26 so as to deform it around the reed 21 with the edges of the slot 35, as indicated at 31, extending over the reed 27 to a substantial extent so that the reed 2? is located below the surface 38 of the armature 26.

At the same time that the edges 3! of the groove 35 are being deformed, as just described,

the remaining surface 33 of the armature 26 isrelieved by application of sufficient pressure thereto and at the same time the sides 4| are correspondingly deformed outwardly slightly beyond the sides 36. This exposes a portion 42 of the reed 21 so that the outer edge thereof is spaced from the surface 39 and, as shown in Figure 3, can have substantially point contact engagement with the round glass rod back stop 7 34. In this manner, in a single operation the "armature 23 is mechanically and electrically connected to the reed 21 and a portion thereof is relieved to provide point contact engagement with the back stop 34.

Solely for the purpose of illustration and in order to indicate design dimensions which may be used in practicing my invention I call attention to the fact that the stainless steel reed 2'! may have a diameter of .016. For one particular type of relay it is 21% long. The armature may be 5% long and the width thereof between the sides 36 may be .078". The surface 39 is relieved for about along the reed 2'! and the sides 4| of this portion are spaced .088 apart. The section 42 of the reed 27 along the relieved portion of the armature 26 extends above the surface 39 about .OO. Using these particular dimensions for the type of relay referred to in the construction and manufacture of the movable contact finger it has been possible to eliminate entirely sticking to the back stop 34.

Since certain further changes can be made in the foregoing constructions and method and different embodiments of the invention can be made without departing from the spirit and scope thereof, it is intended that all matter shown in the accompanying drawing and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. Method of making a reed type, contact finger which comprises positioning a metallic metal of a comparatively tough characteristic completely within a longitudinal slot in one side of an elongated armature of a softer type magnetic alloy, deforming portions of the side of said slot around said reed for a substantial portion of the armature length to effect frictional attachment thereb'etween and incasement of said reed for said substantial length, and relieving the brief remaining portion of the sides of said slot sufficiently to permit only the section of said reed which is coextensive therewith to project above the edges of the slot and said relieved portion of the armature surface, whereby the exposed reed portion of said tougher material forms a durable contacting sur face for engaging contact positioning members on an associated relay structure.

2. In a telephone type relay having at least one set of circuit controlling members comprising a stationary contact, a movable contact-bearing member, limit means for normally positioning the contact-bearing member in a given position, and electromagnetic means for operating said movable member under tension from said given position to a second position to effect engagement of said stationary and movable contacts for circuit controlling purposes, said contact-bearing member comprising a metallic reed stationarily mounted at its one end, an elongated armature having a longitudinally extending slot in one side thereof which substantially inoases and frictionally engages said reed for a substantial portion of the length of said armature and which is relieved for a brief portion to permit an outer face of said reed to extend above said relieved armature surface for a correspondingly short portion of their coextensive lengths, said armature being disposed to efiect engagement of said briefly exposed coextensive reed portion with said limit means upon the tensioned return of said contact-bearing member to said first given position, whereby said tougher reed member is adapted to absorb the wear normally inflicted on said armature in said tensioned return and said frictional incasement of said reed by said armature for said substantial length is effective to minimize flexing and relative movement of the reed and armature resulting therefrom.

ROBERT K. McBERTY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,061,919 Miller May 13, 1913 1,318,178 Reed Oct. 7, 1919 1,706,005 Thompson Mar. 19, 1929 1,907,931 Henderson May 9, 1933 2,106,332 Wilkins Jan. 25, 1938 2,257,900 Crum Oct. '7, 1941 2,307,216 Graham Jan. 5, 1943 2,396,332 McBerty Mar. 12, 1946 FOREIGN PATENTS Number Country Date 129,453 Austria Aug. 10, 1932

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