US2268882A - Relay - Google Patents

Description

Jan. 6, 1942; E. D. LILJA 2,268,882

' I RELAY Filed Aug. 3, 1940 2 Sheets-Sheet l Jan. 6, 1942.

E. D. LILJA RELAY Filed Aug. 3, 1940 ljji 3.

2 Sheets-Sheet 2 ATTORNEYS Patented Jan. 6, 1942 RELAY Edgar-D. Lilia, Rockford, 111., assignor to Barber- Eolman Company, Rockford, 111., a corporation of Illinois Application August 3, 1940, Serial No. 350,397

10 Claims.

The invention relates to relays and particularly to polarized relays.

The primary object of the invention is to provide a relay having extreme sensitivity.

The important increase in sensitivity which I attain is believed to be in large measure attributable to the utilization of afundamentally new combination of operating principles for relays as a class, as will hereinafter more fully appear.

Another object of the invention is to provide a polarized relay characterized not only by its high sensitivity, but also by its ruggedness and simplicity of construction which achieve long life, efiectualness of operation and low cost.

The invention also resides in certain novel combinations and arrangements of the relay parts by virtue of which adverse effects of mounting vibration and power frequency response are minimized.

Further objects and advantages of the invention will become apparent as the following description proceeds, taken in connection with the accompanying drawings in which:

Figure 1 is a general perspective view of a relay embodying the invention.

Fig. 2 is a longitudinal sectional view taken substantially along the line 2-2 in Fig. l, and being in efiect a stop-motion view since it indisates the flux-distribution which is effective to shift the armature from the position shown over to the left hand position indicated in Fig. 3.

Fig. 3 is a longitudinal sectional view similar to Fig. 2 but showing the relay armature as having completed its shift to the left.

Fig. 4 is a longitudinal sectional view similar .to Fig. 3 but indicating the current and flux paths during a current cycle alternate to that indicated in Fig. 3.

Fig. 5 is a longitudinal sectional view similar to Fig. 3 but showing the relay armature in its right hand position.

Fig. 6 is a transverse sectional view taken substantially along the line 6--6 in Fig. 2.

While the invention is susceptible .of various modifications and alternative constructions, I have shown in the drawings and will herein describe ln detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

In the instant exemplification the invention has been shown as embodied in an alternating current polarized relay. This relay comprises a pair of stationary contact points l0 and H on the ends of respective ones of a pair of adjusting screws l2, l3 threaded in'supports 14 which may be mounted on a panel or other suitable base (not shown). Between these stationary contact points I 0, H is a double contact fixed on a resilient spring tongue or finger l6, anchored in cantilever fashion at its upper end on a U- shaped metal bracket, ll and flexible to right or left to close the movable contact l5 against one or the other of the stationary contacts in,

ii and thereby close corresponding controlledcircuits (not shown). Of course, when the movable contact l5 is in its central'or mid-position it is out of engagement with both of the stationary contacts in, ll and both of the alternatively closable controlled circuits are open.

vAdjustment of the bracket ll may be made to vary the initial position of the tongue l6 and its contact l5. For this purpose the bracket is pivoted on a pin li fixed to a suitable base and the bracket is urged into frictional engagement with the face of the base or panel by a compression spring 51* encircling the pin H and interposed between the inner arm of the bracket and a collar W on the pin. To adjust the angular position of the bracket l'l about the pin fil a screw ll is threaded in or out, this pin being arranged to bear against a fixedabutment il A tension spring it, anchored to the inner bracket arm and to the base yieldably holds the nose of the screw El against the abutments fil The actuating mechanism for the relay comprises a horizontal plunger or armature iron or other magnetizable material. This plunger is fixed by screws 68 at its opposite ends to stiffener extensions 59 on the lowerextremities of depending spring fingers l9, which are anchored at their upper ends to the arms of a bracket 28 also fixed on the base (not shown). These fingers is are in turn connected through contractile springs 2! with the central contacts finger (6. Accordingly, when the plunger [8 is shifted endwise to the left (position shown in Fig. 3) the central finger i6 is flexed to close the contact l5 against the stationary contact point l0. Similarly, when the plunger 18 is shifted axially to the right (the'position shown in Fig. 5) the central finger I6 is pulled over to close the contact point l5 against the contact ll; and'when the plunger l8 rests in its centered or mid-position, the movable contact l5 centered out or engagement with the iecontects ill, E11.

omagnetic actuating system lei plunger i8 is next descri-cezl below.

seeding to that it should he rowel,

iii

cont-sot points which might otherwise be caused toy the power frequency response the plunger. This spring errangement also minimizes the efiect of any vibration of the supporting base from which the fingers l9 are hung and which would otherwise tend to shake the center finger it with resultant chattering oi the contact points. 29

Further damping out of undesirable plunger vibration is also 'afiorded by e brake comprising .a resilient wire'iie (Figs; 1 and 2) fixed to one of the spring extensions l9 and arranged to ride irictionally over a pin as the plunger it moves heels and forth. Endwise movement of the plunger is limited by stops at each end, one of which is shown in Fig. l as a bracket 3i preseut= ing a felt button Ell to the adjacent portion of the spring extension ill to limit the letters outward swing.-

In the exemplary electromagnetic system shown (see Fig. 2) the plunger l8, which con stitutes the movable armature of the system,-

projects axially through a casing or stator struc-."

ture, designated generally as 22,'and comprising a cylindrical sleeve 23. This casing also includes end walls 26, rigid with the sleeve 23, and cen= trally apertured as at 25 for free passage of the ends'of the plunger 68, with a fairly large air gap between the adjacent plunger and casing parts as shown. For example, if the casing 22 has an outside diameter of h s inches, the plunger diameter may be 0.265 inch and the holes 25 may be of a diameter to give an air gap from their edges to the main body of the plunger of 0.086 inch. In such case the overall length or the casing may be 2 inches, the main or unreduced portion of the plunger 2% inches long, the end members -26 maybe inch thick and the sleeve 23 may be is inch thick. Additionally, a

eeeeeee pairs oi windings are wound on spools 2B, snugly fitted in the sleeve Note t t .centerpsrtition 26 is made rip of two aperturecl Zerrous seated cesses in the opposed or these thickness of each dish losing suhstel. for one of the end members 2Q, smith central apertures are slightly lerger: W on in the end members. The polarizing windo s PWl, PWa are continuously excited iron: at iii-lic eble source of alternating current, the hastentaneous direction of current flow tor one cycle being indicated hy the dotted arrow line i in Figs. 2 and 3. llt may loe noted, incidentally, at this point that the direction of current flow in the alternate hsli cycles is indicated by the dotted arrow line 09 in Fig. 'l he control windings CW1 and CW2 are, on the other hand, excited with an alternating current having a controlled and variable phase relation with reseect to the current in the polarizing windings, and in the exemplary construction the'conriections of the control windings are such that the directions of current fiowin the two are opposed with respect to each other, as ihdicemel hy the arrow line [1c in Fig. 2. As a generalmotion it may be noted that for one phase relation between i is the magnetomotive forces set up by the windings PW; and CW1 aid each. other while those of the other pair of windings, namely PWB and (Wife, buck or oppose each other, so that the plunger l8 moves to the left (to the position shown in Fig. 3) that is, toward the aiding coils. Similarly, for another or opposite phase relation of the cur rents i and le the magnetomotive force of the windings PWz, CW2 aid each other while those set up by the windings FY11 and CW1 oppose, and the plunger it moves in the opposite direction, that is, to the right (to the position shown in Fig. 5). It will readily be understood by those skilled in the art that the some general efiect noted can be obtained by using oppositely wound (with respect to each other) polarizing windings and like wound control windings rather than like wound polarizing windings and oppositely wound control windings as shown. The details of the fluxes set up by the windings shown and their action on the plunger, under different current phase conditions, will appear more fully below.

so The significance of the structural arrangement center partition 2% is provided in the sleeve 23,

being-rigid with the latter and centrally epertured as indicated at all for free passage or the plunger. The entire casing '22 is made of iron or other ferromagnetic material and serves, in conJunc-' tion with the plunger I8, to form various flux paths as hereinafter more particularly described.

The casing 22 is, like the contact structure, sup ported on a suitable base (not shown) and particularly. to be noted is the fact that none of its parts touch or rub against the plunger l8 so that there is no friction to impede or interfere with the latter's free movement except the adjustable amount provided by the oral-1e28, l! for damping purposes. This is, of course, important ins sensitive device such asthe one herein disclosed.

Within the casing 22, and encircling the plunget ID, are two polarizing windings PW; and Pw2 8nd two control windings CWz'and CW2, arrangedin pairs so that the polarlzing'wlndln: PW; and the control winding CW1 encircle one end portion of substantially half of the plunger l8 and the other twowlndlnzs PW: and cwaset out above will become apparent on connection with an analysis of the relays operation, for, unexpectedly enough, it will be found that the relay involves quite a fundamentally new combination of operating principles, insofar as relays are "concerned; In general, it should be borne in mind that similar relays-have heretofore commonly operated as a result of what may be termed solenoid action. The relay herein shown utilizes not only such a solenoid action, but also supplements it withawhat may be termed a "motor action." It is the utilization of this latter departure from prior practice which apparently accounts in large measure for my relays unusual sensitivity. 3

By "solenoid action"'I have reference to the tendency of a movable magnetizable element, threaded by flux, to move into a position in the flux or magnetic field in which the reluctance of the path for the flux is a minimum. For

example, in the structure shown (see Fig. 2) the encircle the other hall. For this the the flux thresdlnz onc end or other or the accuses plunger) to a position in which the gap is minimized between the plunger and theme of the casing end walls 24 at which the flux is a maximum. Thus, if there is more flux between the left end wall and the plunger than between the right end wall of the casing and the plunger, the plunger will tend to move to the left so as to minimize the length of the air gap between this left end wall and the plunger, such motion being due to the so-called solenoid action. A similar action, in the opposite direction, takes place when the greater amount of flux threads the right hand end of the plunger. It should be observed, incidentally, that it is only the amount, and not the polarity, of the net flux which is important. Thus, when using an alternating current to set up the flux, the polarity of the fiux will reverse for each half cycle of the current. Two such opposite directions of current flow are indicated respectively in Figs. 3 and i. In both cases, however, the preponderance of flux at the left end of the plunger tends to move the latter to the left, even though the directions of the flux are, in the two instances shown, opposite to each other.

As to motor action," I have reference to the well known phenomenon commonly referred to as defined by Arnperes law, namely that when a current carrying conductor lies at right angles to the lines of force in a magnetic field a force is set up tending to displace the conductor in the field.

In the presentinstance the plunger ii! is, in a general sense, utilized both as a movable magnetic member in a solenoid action system and as a movable conductor in a motor action system, the effects. of the two actions on the plunger being made cumulative.

Turning now to the application of these factors in the particular structure shown, it iii be observed, upon reference to Fig, 2, that current Ip of the polarizing windings PWr and PWz sets up a flux i flowing through a long orbital path including the full length of the plunger or armature E8. The control windings CW1, CW2, on the other hand, set up fluxes fcl. and fee, respectively, in the two shorter orbital paths indicated, which extend through respectivehalves of the plunger i8 and have in common only the intermediate portion or center partition 26 of the stator. In the left hand portion of the magnetic structure the fluxes fp and fol aid each other to produce a net flux fm threading the gap between the end of the plunger l8 and the left end wall 24 of the casing. The fluxes fp and ,fcZ buck each other, however, so that a smaller net flux i112 links the plunger 68 and the right hand end wall of the casing. The relative magnitudes of the fluxes are indicated roughly by the corresponding iengths of the arrows. Under the circumstances noted, the solenoid action of the prepoiioierating net flux fni tends to cause the plunger 28 to shift to the left to the position shown in Fig. 3.

The solenoid action described just above is, however, augmented by an important motor action which thefluxes noted also set up. in this connection it should be observed particularly that the plunger 58 is traversed from end to end by flux which has a minimum value, even in its right hand portion, of fn2. When a piece of magnetizable material, such as the plunger 18, is traversed by flux, the individual atoms in the material are realined by the impressed field or flux in such a way that the combined effect of their electron spins may be represented by a current sheath banding the part. This sheath current tor the plunger i8 is indicated by the arrows Is in Fig. 6. At the mid-portion of the plunger !8, however, a net flux fna, equal to the sum of in and fc2, threading between the plunger 58 and the partition 26, cuts across the path of this sheath current. Accordingly, a motor action is set up between the sheath current and the crossing flux fn3, which also tends to shift the plunger 18 to the left. The polarizing windings PW1, PW2 determine the polarity of the sheath current, and the polarity impressed on the control windings, relative to that of the polarizing windings, determines the polarity relationship between the sheath current and the net flux in: entering the mid-portion of the plunger, which relation in turn determines the direction of. the force on the plunger resulting from the motor action. With the flux and sheath current polarity relation indicated in Figs. 3 and 6 the motor action would be to the left (as determined by the socalled left-hand rule) or, in other words, in a direction to augment the solenoid efiect.

Substantially the same type of operation takes place when the phase of the control current in the windings CW1, CW2 is altered so as to shift the plunger 38 to the right and close the movable contact l5 against the stationary contact 1 i. In such case the flux fc'l, set up by the control winding CW2, aids the polarizing winding flux f while the flux fcl, set up by the other control winding CW1, opposes the flux f of the polarizing windings. Accordingly, the net flux fnz exceeds the net fiux fin so that the resulting solenoid action on the plunger tends to move it to the right, to the position of Fig. 5. Furthermore, the polarity relation is reversed between the net flux ,fn3 at the mid-portion of the plunger and the sheath current, so that the efiect of the motor action is also reversed and tends to shift the plunger to the right.

To restore the plunger to its neutral or midposition the voltage applied to the control wind-- ings CW1, CW2 may. be reduced to zero, whereupon only the polarizing windings are effective, and since their chest is balanced there will be no force tending to move the plunger in either direction and it will r tu From the foregoing, lo ill be appreciated that a. very simple relay structure has been provided. Despite this structural roplicity the very unusual operating charac: ics of the relay afiord a high degree of sensitivity, particularly adapt ing the relay for use in various types of control circuits where such sensitivity is often of paramount importance.

I claim as my invention:

1. A polarized relay comprising, in combination, two polarizing coils and two control coils arranged in axially alined pairs with one control coil and one polarizing coil in each pair, the polarizing coils being arranged to produce magnetomotive forces of the same polarity with relation to respective ends thereof but the control coils being arranged to produce magnetomotive forces of opposite polarity with relation to their respective ends, an elongated armature core projecting axially through said pairs of coils, means supporting said armature for free endwise movement, switch means actuated in opposite senses by movement of the armature in respectively opposite directions, and means forming a low reluctance return path for flux set up in said armature core by said coils and extending from one end or said armature to the other end with a m to its mid-position.

loy pass extending from its mid portion and he tween said pairs or coils to apoint adjacent the mid=portion of said armature.

2. A polarized relay comprising, in combina= tion, an elongated maguetizahle armature, means supporting said arncature for endwise move= ment, switch means actuated by movement or" said armature, a stator oi magnetizaole material including three spaced members projecting in proximity respectively with the two end an mid-portions of the armature and having end portions remote from the armature all joined together to form three low reluctance flux paths linking said armature, one path extending lengthwne through the armature and including the stator members at its ends, the second extending through the portion of the armature between its mid-portion and one oi said members at one end of the armature, and the third extending between the mid-portion oi the armature and said member at the opposite end of said armature, means including a polarizing winding for inducing a how of flux through said one path, and means including a pair of control windings for inducing a flow of flux through re= spective ones of said second and third paths.

- 3. A polarized relay comprising, in combination, an elongated magnetizable armature, means supporting said armature for endwise move= ment, switch means actuated by movement oi said armature, a stator of magnetizable ma erial including three spaced members projecting in proximity respectively with the two end and mid-portions of the armature and having end portions remote from the armature all joined to form three low'reluctance flux paths said armature, one path extending aeoassa of hire polarity traversing said armature ae= tween said two points in an orbital path inciud= ing the armature and said first mentioned two portions oi the stator and remote portion oi the latter,'and two control arranged to produce or opposite polarity to each other traversing respective paths in common oniy portion or the stators 6. a reiay combination or a movably mounted armature oi" magnetiaahie material, a magnetiaahle stator having portions proxirrdty to two spaced points on the armature and joined by a portion remote irom the armature, said stator also including a portion cut-ending from said remote portion proximity with a point on the armature intermediate the first inan tioned two points, and exciting means for pro= lewise through the armature and including the stator members at its ends, the second extending through the portion of the armature between its mid-portion and one of said members at one end of the armature, and the third ex-.

tending between the mid-portion of the arma= ture and said member at the opposite end of said armature, means including a polarizing win for inducing a flow 'of flux through said one path, sndmeans including at ieast one control winding for inducing a flow of flux through one of said second and third paths.

4.111 a relay, the combination of a switch, an elongated movable actuating plunger of magnetizable material for said switch, a stator of a. .s; etizable material adjacent said plunger, means for setting up a magnetic field linking said plunger and stator to draw the plunger toward thev statorby'solenoid action, said field traversing the plunger endwise, and means for setting up a magnetic field cutting substantially at right angles across the sheath current band'- ing sa'id plunger substantially adjacent the midportion of the latter by reason of the flux traversing it endwise and with a polarity relative to that of. the sheath current'such as to produce extending only through that portion or the arma= ture lying between said intermediate point and one of said first mentioned points.

7. In a relay the combination oi? a movably mounted armature of magnetizalole material, a magnetizable stator having portions in 11; ty to twospaced points on the armature and joined by a portion remote from the armature, said stator also including an intermediate portion ere v tending from said remote portion into pro m.

ty with a point on the armature intermediate the first mentioned points, and exciting means for producing flux threading an orbital path extending through the armature between said first mentioned points and through the first mentioned portions of the stator adjacent said points and through said remote portion of the stator and for also setting up flux traversing the gap between said intermediate point on the armature =K 1,8aifi intermediate portion of the stator to cut across a sheath current bending the armature and set up bythe first mentioned flux traversing it.

8. A polarized relay comprising, in combine tion, a tubular casing having end walls and a transverse central partition, all of magnetizable material, said end walls and partition having allned central apertures therein, on

in respectively opposite directions, We polarizing windings .in respective halves of the casing defined by said partition andencircling said armsture, and two control windings also disposed in respective halves of the casing defined by said partition and encircling said armature, said polarizing windings being arranged to produce fluxes of like polarity traversing said core and said control windings being arranged to produce" fluxes of opposite polarity to each other traversing the portions of said armature which'they encircle.

9. In a relay, the combination of two resilient spring fingers each fixed at one end to depend from such fixed end in generally parallel spaced relation, an elongated magnetizable armature fixed between and carried by the-lower end portions of said fingers, means including an electromagnetic actuator freely encircling said armature and out of contact with it for moving the same endwise, a laterally movable switch member disposed between said fingers, cooperating stationary switchmembers on each side of said movable switch member and alternatively engage- I able thereby, and contractile springs operatively members remote from their upper ends and carried thereby for endwise movement upon lateral swinging of said members, means including an electromagnetic actuator encircling said armature for moving the same endwise, a laterally movable switch member disposed between said vertical members, cooperating stationary switch members on each side of said movable switch member and alternatively engageable thereby,

and contractile springs operatively connecting said movable switch member and the vertical members on opposite sides thereof.

EDGAR D. LIL-1A.

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