US2638514A

US2638514A - Electric circuit controller

Info

Publication number: US2638514A
Application number: US51261A
Authority: US
Inventors: Paul N Martin
Original assignee: Westinghouse Air Brake Co
Current assignee: Westinghouse Air Brake Co
Priority date: 1948-09-25
Filing date: 1948-09-25
Publication date: 1953-05-12
Anticipated expiration: 1970-05-12

Description

y .12, 1953. Y P. N. Mm; 2,638 51 ELECTRIC cmcur'r comom "F'uea Sept. 25, 1948 flnsulation Fllqi 26 v Fig: 2

INVENTOR. I M. Martin HIS ATTORNEY Insulation Patented May 12, 1953 ELECTRIC CIRCUIT CONTROLLER Paul N. Martin,

Penn Township,

Allegheny County, Pa., assignor to Westinghouse Air Brake Company, a corporation of Pennsylvania Application September 25, 1948, Serial No. 51,261

Claims.

My invention relates to electric circuit controllers, and particularly to contact supporting and operating mechanisms usable in multiple contact relays.

My invention is illustrated herein as applied to a relay including groups of movable contact fingers, and in which the movable contact fingers of each group are connected with the relay armature through the medium of an associated operating member of insulating material pivotally attached to the armature.

One object of my invention is to provide improved means for drivingly connecting an operating member to a contact-carrying finger.

Another object is to provide an improved spring pivot structure for a contact-carrying finger.

Another object of my invention is to provide an improved electrical relay of the type described in Letters Patent of the United States No. 2,198,704, granted to Branko Lazich on April 30, 1940 for Electrical Relays; No. 2,347,834, granted to John W. Lovingston on May 2, 1944 for Electrical Relays; and No. 2,372,594, granted to myself on March 27, 1945 for Mounting for Oscillatory Members.

My invention is described herein as applied to a relay having contact fingers in spaced vertical rows below the relay armature, and in which each row or pair of rows is provided with a contact operating member pivotally attached to the armature. In this relay, the foregoing and other objects of my invention are attained by providing the contact operating member with a pair of spaced opposed convex abutments for each finger. The fingers extend between these pairs of abutments, and each finger carries a leaf spring which is biased to engage one abutment and biases the finger into engagement with the other abutment. Two species of abutment structures and two species of leaf spring arrangements for engaging the abutment structures are illustrated.

The improved hinge structure include a relatively stiff, rigid finger attached at an intermediate point to a very flexible heel spring of the leaf spring type. The other end of the heel spring is rigidly fastened to a fixed support. The stiff spring overlies the flexible heel spring except for a small portion of the latter near the support. Movement of the pivot end of the stiff spring away from the heel spring is limited by a stop structure. The stiff spring extends over the fixed support so that its movement toward the flexible spring is limited by the support itself. In this Way, a hinge structure is provided which can be easily moved by a small force, but which after a short initial movement becomes capable of transmitting large forces without further movement.

Other objects and characteristic features of my invention will become apparent as the description proceeds.

I shall describe two forms of electric circuit controllers embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. l is a side elevational view of a relay embodying my invention. Fig. 2 is a fragmentary front elevational View of a portion of the contacts of the relay of Fig. 1. Fig. 3 is a fragmentary bottom view of the relay of Fig. 1. Fig. 4 is a side elevational view of a modified form of relay contact structure. Fig. 5 is a bottom view of the contact structure of Fig. 4.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Figs. 1, 2, and 3, the relay to which I have shown my invention applied is of the type described and claimed in Letters Patent of the United States to Lazich, No. 2,198,704, referred to hereinbefore, and comprises two magnetizable pole pieces I secured as by riveting to a nonmagnetizable supporting bracket 2, which supporting bracket, in turn, is fastened by suitable means to a backplate 4 of insulating material that can be readily moulded, such for example, as a phenol condensation product. The pole pieces extend upwardly through slots (not shown) formed in the bracket 2, and are provided at their upper ends with outwardly extending portions la. A magnetizable backstrap 6 is secured at its ends to the outwardly extending portions la of the pole pieces I by means of screws 1, and mounted on this backstrap is an insulating spool 8 provided with an energizing winding 9. The portions of the pole pieces which are located on the underside of the top plate extend toward each other, and have their lower pole faces lb ground to lie in the same plane.

The relay also comprises a magnetizable armature l5 which is pivotally supported at one end in trunnion screws l6 for swinging movement toward and away from the pole faces lb of the pole pieces I. The trunnion screws IE, only one of which is visible in the drawings, are supported in outstanding lugs I7 secured by means of screws 19 to a depending portion 20 of the bracket 2.

The relay further comprises an L-shaped permanent magnet 2! which is secured at one end to the outer pole piece I, and the other end of which extends underneath the armature l5 opposite the pole face lb of the outer pole piece I in such manner that when the armature I5 is swung away from the pole pieces I it will be swung toward the permanent magneig'ta'nd vice versa. 'The armature is prevented: from actually touching the pole pieces I by means of a core pin 22 of nonmagnetizable material riveted to the armature adjacent its forward end. A core pin 23 similar to the core pin 22- prevents the armature from actually touching the pole .face

of the permanent magnet -2 1..

Assuming that the lowerendofthe: permanent letters N and S in the drawings, when the. w-inding 9 is deenergized, the armature it? will drop under the influence of gravity tothe position shown, and under theseconditions va part ofv the flux from the permanent magnet will pass lengthwise through the armature and will exert on .the armature a torque which assists the pull ofgravity in retaining the armature in. the position shown. When,.however, the winding 9 becomes, energized, if it is energized in such direction that the front .pole piece I becomes asouth pole and the rear pole piece I. becomes anorth-pole, the permanent magnet and electromagnet fiuxeswill buck each other, and as the electromagnet flux builds. upon the armature, a point. will .be reached atwhich the upwardv pull exerted. on the armature by this flux will exceed the downwardpull due to the permanent magnet flux and the force of. gravity, and when this happens the armature it will swing upwardly toward the pole pieces I .to the position determined by the corepin 22. If. the winding 9. is energized .insuch av direction that the front pole piece 1 becomes a north pole and the rear pole piecel becomes a south pole when the armature i5 occupiesits deenergized position, the fiux due to both the electromagnetiand the permanent magnet will then threadthe armature M in the same direction, and under these .conditions the armature. l5 .Will remainin the. position shown even thoughithe energization of the winding I5 is increased to many timesitsnormal value.

It should be ..particularly pointed out that,..if the polarity of the permanent magnet 2 i. be .reversed from that showninthe drawings, the armature will operate in a mannersimilar .to that just describediexcept for the fact that the polarity of thev current whichamustbe. supplied to winding ii to cause itto pick up will then be reversed.

A contact finger operating memberfd, preferably formed of moulded insulating material, is

pivotally connected atits upper end tothe armae ture l5. In the arrangements shown. inFigs. 1, 2, and 3, one operating memberil l isprovicled for each pair of verticalrows of contactfingcrs. Spaced pairs of pins or: abutments project from.

the opposite. sides of operating member 2A,. each moves freely on pin gers Zlwhich engage the pins 25 are smooth and fiat so that they move .freely on those convex surfaces. The spring 23 is also flat so that it The spring its is pro vided with a concave portion 2% between two convex portions 2%. Because it is contoured in this manner, the spring 2%) not only moves freely on the pin 25, but accidental endwise movement of finger 2i. and spring 2i! out from between the

pins

25 and 26 isprevented.

A flexible heel spring 3% is provided for supporting the opposite end of each of the rigid contact fingers 27. Each of the springs it is a leaf spring. havingone of its ends attached to the finger 2Y1. at an intermediate point on the finger and having its. opposite end attached to a fixed support 3 l. The rigid fingers are long enough so that their extremities Eia overlie the ends-of the fixed support 3 l Afixed stop 32 is attached to each of the supports 3 l ,and is spaced a short distance above it, overlying the tip El a of the rigid finger 2?.

Near its center, each finger 2i carries either a front movablecontact. 33, a back. movable contact 3d, or. both. Stationary frontcontacts35 are provided, in alignment with. the movable front contact 33. Each contactiiii iscarricd at the ends of a leaf spring 36. attached to a fixed support 37. Each leaf springtii is self-biased to carry the contacts 35 toward the movable contact 33,.but its movement in that direcion is limited by a fixed stop memberv 38;

Stationary back contacts 353 are. provided, each carried at the-end of aleaf spring it Whose opposite. end is attached .to a fixed support. The leaf springs 4t bias the contacts 3% toward their associated movable contacts, and their movement in that direction is limited by another stop member 38.

Operation of Figs. 1 to 3 The parts .are shown in the drawings in the position'they-assume when the relay winding 9 is deenergizedt The "back; contacts are therefore closed and the front contacts open. Starting with these conditions, let it be assumed that the winding 9 is energized, causing armature iii to be moved upwardly, carrying with it the contact finger operating member lid. The sp gets and 29 are-stiif enough so that the fingers cl. are then raised with no'lost motionbetween them and the operating member E l. When the contact 33 en gages the stationary contact 35, then the upward movement of finger-2i is slowed, and the

springs

28 or 29 and 35 are compressed. Additional up- Ward-movementof the 24 is effective to increase the contact pressure. When the springs 28 and. 29 have been 'suiiiciehtly compressed, the front-contact supporting springs 3t deflect with further upward motion of the operating member 24. The right'ends of the rigid contactfingers are solidlysupported by the fixed support ti at this time." The contactfingers 22!- are eufiiciently rigid that they do not distort as the pressure at the contact is-thus 'increase'dz" When the relay winding ii is deenergized; the armature i5 and contactoperating 'rnemberd l drop)" The left endsof'the fingers 27 are then positively driven by the pin25. The fingers 21 .pivot on the leaf springs 30.

When the back contacts associated with the lower finger 21 engage, downward movement of the central portions of the fingers 21 is resisted by the back contact spring 40. As the left end of the lower finger 21 continues to move downward, its right end 21a rises and engages the stop As soon as the stop 32 is engaged, the further downward movement of the contact operating member 24 causes compression of the back contact spring 40. Since there is no back contact 39 associated with the upper finger 21, its downward movement is not resisted, and consequently its right end does not rise to engage its stop 32.

The

pins

25 and 26 provide in efi'ect a lostmotion connection between the operating member 24 and the rigid contact fingers 21. All the lost motion in these connections is taken up, however, by the

springs

28 and 29. By virtue of this connection, it may be seen that it is not necessary to make any adjustment between the various contact fingers and the driving pins during manufacture. The

springs

28 and 29 will take up all the lost motion, regardless of variations in dimensions of the parts due to manufacturing tolerances. Furthermore, since all the

pins

25 and 26 are rigidly connected to the operating member 24, the stresses applied to one pair of pins are not transmitted to the pair of pins on the opposite side of the operating member. It is therefore not necessary that the front and back contacts be arranged in pairs on each finger, nor that the fingers be arranged in pairs on opposite sides of the operating member.

My improved pivot heel spring arrangement including the leaf spring 30 and the stop 32 for the rigid finger 21 insure that the pivoting movement of the finger between its two positions requires only a small operating force. At the same time, the stifiness of the finger 21 is sufilcient to insure that it will not distort as the contact pressure is increased after the finger tip 21a has engaged the stop 32 or is backed up by the fixed support 3|.

Figs. 4 and 5 I have illustrated in Figs. 4 and 5 a somewhat different type of contact operating structure in which each vertical row of contact fingers has its own opera-ting member, instead of using one operating member for two adjacent vertical rows of contact fingers as in the previous modification.

Referring to Figs. 4 and 5, there is shown an operating member 4| whose upper end is pivotally connected to a relay armature by suitable means not shown. The operating member 4| is provided with a recess 4|a for receiving the end of a contact finger 42. The sides of recess 4| :1 are smoothly contoured to form a set of opposde contact abutments 4lb and 4|c. A leaf spring 43 is attached to the finger 42 and extends between the abutments MI) and Me. The spring 43 is generally similar to the spring 29 of Fig. 1. It is provided with a concave portion 43a for engaging the abutment Me. A pair of convex portions 43?) lies on the opposite sides of the concave portion 43a, and help to prevent longitudinal movement of the finger 42 with respect to arm 4|.

If desired, such longitudinal movement of finger 42 with respect to arm 4| may be further prevented by the use of a U-shaped locking piece 44, whose arms span the operating member 4| and are provided at their ends 44a with hooks engaging notches 42a in the contact finger 42.

The pivotal support for the opposite end of finger 42 may be the same as that for fingers 21 in Fig. l, as illustrated in Fig. 4.

Although I have herein shown and described only two forms of electric circuit controllers embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims Without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. Electric circuit controlling apparatus, comprising a rigid finger, operating means for positioning one end of the finger, a fixed support adjacent the opposite end of the finger, a pivot spring connecting an intermediate point on the finger to the support, a stop spaced from the support for limiting the movement of said opposite finger end away from the support, a first electric contact on the opposite side of the finger from said stop, a second electric contact, and spring means yieldably supporting the second contact in alignment with the first contact, so that upon movement of said one finger end in a contact-making direction, said pivot spring yieldably supports said opposite end until the contacts engage, whereupon said opposite finger end is moved to engage its stop, and thereafter the finger pivots about said stop and the spring means supporting the second contact yields.

2. Electric circuit controlling apparatus, comprising a rigid finger, an operating member having a pair of spaced facing abutments straddling one end of the finger, a spring on the finger engaging one abutment and biasing the finger into engagement with the other abutment, a fixed support adjacent the opposite end of the finger, a pivot spring connecting an intermediate point on the finger to the support, a stop spaced from the support for limiting the movement of said opposite finger end away from the support, a first electric contact on the opposite side of the finger from said stop, a second electric contact, spring means yieldably supporting the second contact in alignment with the first contact, and means for moving the operating member, said pivot spring being efiective upon movement of said one finger end in a contact-making direction to yieldably support said opposite end until the contacts engage, whereupon said opposite finger end is moved to engage its stop, and thereafter the finger pivots about said stop and the spring means supporting the second contact yields.

3. Electric circuit controlling apparatus, comprising a rigid finger, operating means for positioning one end of the finger, a fixed abutment adjacent one side of the opposite end of the finger, a leaf spring lying along the finger and connecting an intermediate point in the finger to the abutment, a stop for limiting the movement of said opposite finger end away from the abutment, first and second movable electric contacts carried on the opposite sides of the finger, first and second stationary electric contacts, means yieldably supporting the stationary contacts in alignment with their respective movable contacts, so that upon movement of said one finger end in a direction to engage the contact on the abutment side of the finger, said spring yieldably supports said opposite end until the contacts engage, whereupon said opposite finger end is moved to engage its stop, and thereafter the finger pivots answers.

about said stopg-ancl sozthatauponmovementaof said one fingers-end the opposite: direction, said spring yieldably supports; said opposites end until 1 .the contacts engage, whereupon :said mopeposite finger end moves until :it is stopped by said abutment and thereafter: the finger: pivots about said abutment.

4. Electric circuit controllingapparatus; com.- prisinga stationary'contactga movable contact, a finger. pivotallyrmountedxat. one end and supporting said movable e'contactzan operating member recessed to receive the free end ofasaidsfinger; the si'descoft-said :recess being .formedcby two facing convex abutments, a spring on the finger enie gaging/one of c said 'abutments :;and biasing the fingerdnto'engagement: withvthe other abutment, said spring and finger having surfaces nontoured to move. freely on said convex abutmentaimeans for moving" said operating imemberstowpivot; the

finger :and .move the movable :contact into and out Ofl engagement withwthe stationary. contact, and aalocking member for holdingthe free end of the fingersin the recess, said locking: member being 2 a U -shaped: piecestraddlingsthe. operating memberand having the ends ofits arms'attach'ed 5 to thefinger: 1

5. Electric: circuit controlling: apparatus; comprisiugma:v rigid" finger;:operatingrmeansz-forz positioning one end of the fingerrfirstspring means yieldably aSlXPDOl,biI1g-..the aopposite end of the fingeraasstop sforalimitingwthe movement of said oppositefingerend, a firstelectric contact on the opposite sideof the finger from said stop, a second electric contactrisecond' spring means yieldablyzsupporting the second contact in alignment with the first acontactyso that upon movement of saidsone finger end inia contact-making direction; said 'sfirst :spring' 1 means 1yieldab1y supports said :oppositawend --until :the contacts engage, whereuporrsaid oppositex'finger end is moved to engageeits'lstop and thereafter the finger pivots aboutvsaid-istop andthe'second spring means supporting the second contact yields.

PAUL N. MARTIN.

References.iCitedint-the file of. this patent UN I'I ED. STATES PATENTS Numbers" Name. Date 1,660,877.- Manson s Feb. 28, 1928 2,021,7U6..1 if'lwyman Nov. 19, 1935 2372;594' Martin Mar. 27, 1945 2,490i280 "I Rees: Dec. 6, 1949