US2140604A - Electrical relay - Google Patents

Description

Dec. 20, 1938. C. 5, SNAVELY 2,140,604

ELECTRICAL RELAY Filed April 28, 1937 2 Sheets-Sheet l Fig-5f INVENTOR CZQPQHOQ S cweg.

HIS ATTORNEY Dec. 20, 1938. c, s. sNAvELY ELECTRICAL RELAY' Filed April 28, 1937 2 Sheets-Sheet 2 INVENTOR Clarence S avelg.

/HS ATTORNEY Patented Dec. 20, 1938 UNITED STATES PATENT OFFICE ELECTRICAL RELAY Application April 28, 1937, Serial No. 139,535

7 Claims.

My invention relates to electrical relays, and particularly tofpolar relays for use in centralized traffic controlling systems for railroads such, for example, as that disclosed and claimed in an application for Letters Patent of the United States, vSerial No. 31,592, filed by myself and others, on July 1-6, 1935, for Remote control systems.

One object of my invention is to provide a polar relay of simple, rugged, and compact construction which will operate without appreciable wear or change in operating characteristics over a long period of time, and for a very large number of operations.

Another object of my invention is to provide a quick acting polar relay in which the inertia of the armature is reduced to a minimum, and in whichimproper operation due to overenergization of the relay is prevented.

A further object of my invention is to provide a reliable polar relay which is inexpensive to manufacture.

Further objects and characteristic features of my invention will appear as the description proceeds.

I shall describe one form of relay embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1 and 2 are front and rear elevational views showing one form of relay embodying my invention, the front and rear cover plates of the relay being removed to better illustrate `the construction of the operating parts. Fig. 3 is a vertical sectional View of the relay shown in Fig. 1. Fig. 4 is a sectional view taken on the line IV-IV of Fig. 1. Fig. 5 is a detail View of the armature of the relay together with the insulating member which supports it and the flexible contact fingers of the relay. Fig. 6 is a top plan View of the insulating spool '25 and associated coil 26 comprising part of the operating winding of the relay.

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

Referring to the drawings, the relay in the form here shown comprises a rectangular frame I of insulating material that can be readily moulded, such for example, as a phenol condensation product, which frame supports all of the operating parts of the relay. Provided on the frame I at its upper end are a pair of depending lugs 2 and 3 having threaded inserts 2liL and 3a moulded therein, and provided on the frame I at its lower end are a pair of upstanding lugs 4 and 5 similar to the lugs 2 and 3, which latter lugs have threaded inserts 4B and 5a moulded therein. A U-shaped yoke 6 of magnetizable material is clamped against the rear faces of the lugs 2 and 4 by means of screws 'I which pass through clearance holes in the legs 6a and (ib of the yoke 5 and are screwed into the inserts 2a and 4e, and a similar yoke 8 is clamped against the rear faces of the lugs 3 and 5 by means of screws 9 which pass through clearance holes in the legs 8a and 8b of this latter yoke and are screwed into the inserts 3EL and 5a. The yokes 6 and 8 are disposed with their upper and lower legs in spaced confronting relation, and have their ends ground, chromium-plated, and polished for a purpose which will appear hereinv after. The yokes 5 and 8 are constantly magnetized by means of a pair of U-shaped permanent magnets I0 and II having ground ends which engage the yokes at their rear sides, The permanent magnets I0 and II are held in place i in a manner which will be described more fullyhereinafter.

The frame I is further provided at its medial portion in a vertical direction, as viewed in Figs. 1 and 2 with a pair of inwardly extending lugs I3 and I4 having moulded in their opposite sides threaded inserts I3a, |311, and I4a, Mb, respectively. A front pivot support I5, having a xed front pivot IB riveted thereto, is secured to the lugs I3 and I4 at their forward sides by means of screws il screwed into the inserts I3a and Ia, and a rear pvot support I8 having an adjustable rear pivot I9 mounted therein is secured to the lugs I3 and I4 at their rear sides by means of screws 20 screwed into the inserts I3b and Mb. The rear pivot I9 is screwed through a threaded hole 2l provided in the rear pivot support in horizontal alignment with the front pivot I6, and is arranged to be locked in an adjusted position by means of a lock nut 22,

Pivotally mounted on the front and rear pivots I6 and I9 is a member 23 of insulating material that can be readily moulded, and moulded into this member adjacent the rear end thereof is an armature 24 of suitable magnetizable material. such for example, as silicon steel. The upper and lower ends of the armature 24 extend between, and cooperate with, the confronting ends of the upper and lower legs of the magnetizable yokes 6 and 8 in such manner that the armature is free to swing between a normal extreme position in which the upper end of the armature engages the chromium-plated end of the leg 6a of the yoke v(i, and the lower end of the armature engages the chromium-plated end of the leg il"l of the yoke 8, and a reverse extreme position in which the upper end of the armature engages the chromium-plated end of the leg 8a of the yoke 8, and the lower end of the armature engages the chromium-plated end of the leg 6b of the yoke 6. To improve the magnetic efficiency of the relay and prevent wear, the ends of the armature are tapered in such manner that when the armature is swung to either extreme position, the engaging portions of the armature and the yokes will be disposed in flat surface relation, and the tapered surfaces oi the armature are chromiumplated.

A hollow spool 25 having a coil 26 wound thereon surrounds the upper end of the armature, and a similar spool 21 having a coil 28 wound thereon surrounds the lower end of the armature. The spool 25 is held in the proper vertical position by means of the lugs 2 and 3 and the lugs I3 and I4, and in the proper horizontal position by means of notches 25a (see Fig. 6) which receive the yokes 6 and 8. The spool 21 is similarly held in the proper vertical position by means of the lugs 4 and 5 and the lugs I3 and I4, and in the proper horizontal position by means of notches which receive the yokes 6 and 8. The leads 26n and 2Gb of the coil 26 are soldered to the inner ends of coil connectors 29a and 29b which are moulded into the opposite sides of the frame I, and the leads 21a and 21b of the coil 21 are soldered to the inner ends of coil connectors 30EL and 30b which are likewise moulded into the opposite sides of the frame I. The coil connectors 2921, 29h, 38a, and 3l)b project through the outer side of the frame I far enough to permit external circuit connections to be readily soldered to their outer ends. In practice, the coils 26 and 28 will usually be connected in series in an operating circuit which is at times supplied with current of normal polarity, and at other times with current of reverse polarity, and together constitute the operating winding of the relay. The coils 2S and 21 may, however, if operating conditions require, be included in separate circuits, as will be readily understood.

The forward end of the insulating member 23 is provided with an enlarged portion 23a, and moulded into this enlarged portion are four iiexible contact ngers 35, 38, 31, and 38. Each of these ngers has a long end and a short end projecting out of the insulating member in parallel spaced relation, and the short ends of the lingers are connected by means of iiexible leads 38, 40, 4I, and 42 with circuit connectors 43, 44, 45 and 46, respectively, which are moulded into the frame I above and below, as the case may be, the coil connectors 28h, 29a, 30e, and 38h, and which connectors project through the sides of the frame I to permit external circuit wires to be soldered directly thereto. The long ends of the fingers extend toward the four corners of a rectangle, and cooperate at their outer ends with fixed normal contact members 35a, 36a, 31a, and 38a and xed reverse contact members 351, 36h, 31h, and 38h, respectively, which are moulded into the sides of the frame I above and below the circuit connectors in a manner which will be readily apparent from an inspection of the drawings. The front and back contact members are each provided at their inner ends with a portion which is bent at an angle to the main part of the contact member in such manner that when the armature 24 is midway between its two extreme positions, the bent portion of each contact member will extend parallel to the associated iinger, and each bent portion is provided with a pair of contact buttons 48 which cooperate with similar contact buttons 41 provided on the associated iiexible contact ringer to provide a low resistance contact. The outer ends of the fixed Contact members extend through the side of the case in the same manner as the ends of the coil connectors and the circuit connectors topermit circuit wires to be readily soldered directly to these members. The parts are so proportioned that when the armature is midway between its normal and reverse positions, the contact buttons 41 on each finger will be midway between the contact buttons 48 on the associated normal and reverse xed contact members, but that when the armature is swung to its normal extreme position, the contact buttons 41 on the contact lingers will then engage the contact buttons 48 on the fixed normal contact members to close normal contacts 35-35a, 36-362, 31--31a, and 38-38, and that when the armature is swung to its reverse extreme position, the contact buttons 41 on the fingers will then engage the contact buttons 48 on the fixed reverse contact members to close reverse contacts 35-35b, SIS- 3611, 31-31b, and 38-38b. The parts are further so proportioned that when the armature occupies either its normal or its reverse extreme position, the flexible contact iingers will be flexed a slight amount intermediate their ends, whereby an eiiective low resistance contact is provided between the cooperating contact buttons.

The relay further comprises a back cover plate 50 of moulded insulating material, and a front cover plate 5I also of moulded insulating material.

These cover' plates are clamped against the front and the rear sides, respectively, of the frame I by means of screws 52, and together with the frame form a case which encloses all of the operating parts of the relay. The screws 52 pass through suitable clearance holes in the rear cover plate and in the frame and are screwed into threaded inserts provided in the front cover plate. The front cover plate is formed with a. window 53 which is closed by a window pane 54, whereby all of the parts of the relay can be readily inspected without the necessity for removing the cover plates. 'Ihe back cover plate is provided with recesses 55 which receive the ends of spring clips 56, which clips, when the rear cover plate is fastened in place, engage the rear faces of the magnets to hold the magnets in the proper operative relation with respect to the magnetic yokes.

Assuming that the left-hand ends of the permanent magnets Il] and II, as viewed in Fig. 1, are north poles and the opposite ends are south poles, both legs of the magnetic yoke 6 will become north poles while both legs of the magnetic yoke 8 will become south poles. Under these conditions, iux will iiow from the yoke 6 to the yoke 8. This flux will distribute itself in the air gaps between the confronting ends of the legs of the yoke in such away as to allow the greatest amount of iiux to flow. That is to say, when the armature is swung to its normal extreme position in which it is shown in the drawings, the greater part of the flux which passes from the yoke 6 to the yoke 8 will flow downwardly through the armature 24, but when the armature is swung to its reverse extreme position, the greater part of this iiux will then iiow upwardly through the armature. It will be apparent, therefore, that botlr the amount and the direction of the polarizing iiux which passes lengthwise through the armature depends upon the particular position of the armature with respect to the confronting ends or the legs of the yokes 6 and 8. When the armature is midway between its two extreme positions, there is no polarizing flux through the armature in the direction of its length because both ends of the armature are at the same magnetic potential, and under these conditions, all of the flux which passes from the yoke 6 to the yoke 8 will pass through the air gaps between the confronting legs la and 8a and 6b and 8b.

When the operating winding of the relay is supplied with current, the upper end of the armature will become a north pole and the lower end of the armature will become a south pole, or vice versa, according as the operating winding is then supplied with current of reverse polarity or with current of normal polarity. Assuming that the armature occupies its normal extreme position in which it is shown in the drawings and that the operating winding is supplied with current of reverse polarity, the upper end of thel armature will be repelled from the leg (ia of the yoke 6 and will be attracted toward the leg 8a of the yoke 8, and the lower end of the armature will be repelled l 'from the leg 8b of the yoke 8 and will be attracted toward the leg 6b of the yoke 6. As a result, the armature will quickly move from its normal posi.- tion to its reverse position and will thereby open the normal contacts of the relay and close the reverse contacts. As soon as the armature reaches its reverse position, the current can then be removed from the operating winding and the armature will then remain in its reverse position and Will hold its reverse contacts closed. by virtue of the polarizing flux passing through the armature, as will be readily understood.

If, when the armature occupies its reverse position, the operating winding is supplied with current of normal polarity, the upper end of the armature will then be repelled from the leg ila of the yoke 8 and will be attracted toward the leg ln of the yoke 6, while the lower end of the armature will be repelled from the leg Eb of the yoke 6 and will be attracted toward the leg 8lo of the yoke 8. The armature will therefore quickly move from its reverse position to its normal position and will thus open its reverse contacts and close its normal contacts. As scon as the armature has reached its normal position, the current may again be removed from the operating winding and the armature will then remain in the position `shown. If, when the armature occupies its normal position, current of normal polarity is supplied to the operating winding, or, if, when the armature occupies its reverse position current of reverse polarity is supplied to the operating winding, the armature will be held in the position which it then occupies in a manner which will be readily understood without further detailed description.

With a relay constructed in the manner thus far described, it will be apparent that when the armature occupies its normal position and the operating winding is supplied withl current of reverse polarity to cause the armature to move to its reverse position, the ux which is set up in the armature will tend to force ilux through the permanent magnets in the reverse direction from their proper magnetization, and if the armature has sufficient inertia and the iluX is of suflicient magnitude, two things may occur which will ad-l versely affect the operation of the relay. If the flux in the permanent magnet actually becomes reversed in direction before the armature reaches its mid position, the armature will tend to return to its original position. That is to say, the relay will not pole as intended, and as a result a failure in the system which it controls will occur. If the magnetomotive force set up by the operating Winding is great enough, and if the permanent magnet is not properly designed, the degree of magnetization of the permanent magnet will become changed and will cause a resulting change "in the calibration of the relay. This same action may occur when the armature of the relay occupies its reverse position and the operating winding of the relay is supplied with current of normal polarity. The failure of the armature to reverse in the proper manner is known as locking and cannot occur in a relay embodying my invention for the following reasons. In the rst place, the moment of inertia of the movable parts of the relay has been made small by reducing its weight and by pivoting it at its center of gravity, so that a very small force is required to cause the armature to reverse. In the second place, the cross-sectional area of the armature has been made small enough' so that the armature will saturate when normal operating potentials are placed across the winding, thereby limiting the amount of ilux which the operating winding can supply to the permanent magnet. In the third place, the demagnetizing leffect of the operating winding on the permanent magnet, as well as the demagnetizing effect due to external fields has been almost entirely eliminated by properly proportioning the dimensions of the permanent magnet, and by properly controlling the process by which the magnet is heat treated and the process by which it is magnetized.

One advantage of a relay constructed in the manner described is that since the armature and associated moving parts of the relay are light in Weight, the relay is capable of high speed operation.

Another advantage of a relay constructed in the manner described is that the relay will satisfactorily operat-e contacts capable of carrying relatively large currents in response to a relatively small power input.

Another advantage of a relay constructed in the manner described is that it is possible to inspect all of the vital parts oi the relay without removing the relay from service. Thus, if the contacts become worn or pitted, or if they are bent out of shape, or if the magnetic gaps get out of adjustment, these facts may be detected by casual inspection and the relay removed from service. If circuit failures occur, the contacts can be tested from the front of the relay.

A further advantage of a relay constructed in the manner described is that the parts of the relay are so constructed that very little adjustment of the contacts is required, and that, as a result, contact failures due to warping are unlikely to occur.

A still further advantage of a relay constructed in the manner described is that due to the arrangement of the parts no forces are transmitted through bearing surfaces except any minor forces which might exist due to unbalances in the magnetic circuit and that due to the weight of the movable element. This very materially reduces the wear on bearing surfaces.

Although I have herein shown and described only one form of relay embodying my invention, it is understood that various changes and modiflcations 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. A relay comprising a frame of moulded insulating material, two U-shaped magnetizable yokes secured to said frame with their legs in spaced confronting relation, a pair of pivot supports secured to said frame and provided with aligned pivots, an insulating member pivotally' mounted on said pivots, an armature carried by said insulating member and having its ends disposed between the confronting ends of said yokes for movement between normal and reverse positions, a permanent magnet connected with said yokes for polarizing said relay, a winding surrounding said armature, contact fingers carried by said insulating member, xed contact members moulded into said frame and cooperating with said contact fingers, and front and back cover plates secured to the front and rear sides respectively of said frame and forming with said frame a case which encloses all of the operating parts of said relay.

2. A relay comprising a rectangular frame of moulded insulating material, a first pair of lugs formed on one end of said frame, a second pair of lugs formed on the other end of said frame, a third pair of lugs formed on said frame intermediate its ends, two U-shaped magnetizable yokes secured to the lugs of said rst and second pairs of lugs with their legs in spaced confronting relation, front and back pivot supports secured to the opposite sides of said third pair of lugs and provided with aligned pivots, a member of moulded insulating material pivotally mounted on said pivots, an armature moulded into said member and having its ends disposed between the confronting ends of said magnetizable yokes for movement between normal and reverse positions, a permanent magnet connected with said yokes for polarizing said relay, whereby said armature is magnetically biased to its nearest extreme position, a winding surrounding said armature, and contact fingers moulded into said insulating member and cooperating at their free ends with fixed normal and reverse contact members moulded into said frame to form normal and reverse contacts which are closed according as said armature occupies its normal or its reverse position.

3. A relay comprising a rectangular frame of moulded insulating material, a rst pair of inwardly extending lugs formed on one end of said frame, a second pair of inwardly extending lugs formed on the other end of said frame, a third pair of inwardly extending lugs formed on said frame intermediate its ends, two U-shaped magnetizable yokes secured to the lugs of said first and second pairs of lugs with their legs in spaced confronting relation, front and back pivot supports secured to the opposite sides of said third pair of lugs and provided with aligned pivots, a member of moulded insulating material pivotally mounted on said pivots, an armature moulded into said member and having its ends disposed between the confronting ends of said yokes for movement between normal and reverse positions, a permanent magnet connected with said yokes for polarizing said relay, whereby said armature is magnetically biased to its nearest extreme position, a winding surrounding said armature, contact fingers moulded into said insulating member in such manner that said fingers extend in radial spaced relation toward the four corners of a rectangle, and fixed contact members moulded into said frame and cooperating with said flexible contact ngers. I

4. A relay comprising a rectangular frame of moulded insulating material, a first pair of inwardly extending lugs formed on one end of said frame, a second pair of inwardly extending lugs formed on the other end of said frame, a third pair of inwardly extending lugs formed on said frame intermediate its ends, two U-shaped magnetizable yokes secured to the lugs of said first and second pairs of lugs with their legs in spaced confronting relation, front and back pivot supports secured to the opposite sides of said third pair of lugs and provided with aligned pivots, a member of moulded insulating material pivotally mounted on said pivots, an armature moulded into said member and having its ends disposedv between the confronting ends of said yokes for movement between normal and reverse positions, a permanent magnet connected with said yokes for polarizing said relay, whereby said armature is magnetically biased to its nearest extreme position, a winding surrounding said armature, contact fingers moulded into said insulating member and cooperating at their free ends with xed normal and reverse contact members moulded into said frame to form normal and reverse contacts which are closed according as said armature occupies its normal or its reverse position, and front and back cover plates secured to the front and rear sides respectively of said frame and forming with said frame a case which encloses all of the operating parts of said relay.

5. A relay comprising a rectangular frame of moulded insulating material, a iirst pair of inwardly extending lugs formed on one end of said frame, a second pair of inwardly extending lugs formed on the other end of said frame, a third pair of inwardly extending lugs formed on said frame intermediate its ends, two U-shaped magnetizable yokes secured to the lugs of said first and second pairs with their legs in spaced confronting relation, front and back pivot supports secured to the opposite sides of said third pair of lugs and provided with aligned pivots, a member of moulded insulating material pivotally mounted on said pivots, an armature moulded into said member and having its ends disposed between the confronting ends of said yokes for movement between normal and reverse positions, a permanent magnet connected with said yokes for polarizing said relay, whereby said armature is magnetically biased to its nearest extreme position, a winding surrounding said armature, and contacts operatively connected with said armature.

6. A relay comprising a rectangular frame of moulded insulating material, a rst pair of inwardly extending lugs formed on one end of said frame, a second pair of inwardly extending lugs formed on the other end of said frame, a third pair of inwardly extending lugs formed on said frame intermediate its ends, two U- shaped magnetizable yokes secured to the lugs of said first and second pairs with their legs in spaced confronting relation, front and back pivot supports secured to the opposite sides of said third pair of lugs and provided with aligned pivots, a member of moulded insulating material pivotally mounted on said pivots, an armature moulded into said member and having its ends disposed between the confronting ends of said yokes for movement between normal and reverse positions. a permanent magnet connected with said yokes for polarizing said relay, whereby said armature is magnetically biased to its nearest extreme position, a rst spool surrounding one end of said armature and held in place longitudinally between the lugs of said rst and third pairs and held in place laterally by notches formed therein which receive said yokes, a rst coil wound on said rst spool, a second spool surrounding the other end of said armature and held in place longitudinally between the lugs of said second and third pairs and held in place laterally by notches formed therein which receive said yokes, a second coil wo-und on said second spool, and contacts operatively connected with said armature.

7. A relay comprising a rectangular frame of moulded insulating material, a first pair of inwardly extending lugs formed on one end of said frame, a second pair oi inwardly extending lugs formed on the other end of said frame, a third pair of inwardly extending lugs formed on said frame intermediate its ends, two U-shaped magnetizable yokes secured to the lugs of said first and second pairs with their legs in spaced confronting relation, front and back pivot supports secured to the opposite sides of said third pair of lugs and provided with aligned pivots, a member of moulded insulating material pivotally mounted on said pivots, an armature moulded into said member and having its ends disposed between the confronting ends of said yokes for movement between normal and reverse positions, a permanent magnet connected with said yokes for polarizing said relay, whereby said armature is magnetically biased to its nearest extreme position, a rst spool surrounding one end of said armature and held in place longitudinally between the lugs of said rst and third pairs and held in place laterally by notches formed therein which receive said yokes, a first coil wound on said rst spool, a second spool surrounding the other end of said armature and held in place longitudinally between the lugs of said second and third pairs and held in place laterally by notches formed therein which receive said yokes, a second coil wound on said second spool, and contact fingers moulded into said insulating member and cooperating at their free ends with fixed normal and reverse contact members moulded into said frame to form, normal and reverse contacts which are closed according as said armature occupies its normal or its reverse position.

CLARENCE S. SNAVELY.

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