US2172888A

US2172888A - Electrical relay

Info

Publication number: US2172888A
Application number: US732857A
Authority: US
Inventors: Lazich Branko; Harry E Ashworth
Original assignee: Union Switch and Signal Inc
Current assignee: Hitachi Rail STS USA Inc
Priority date: 1930-01-14
Filing date: 1934-06-28
Publication date: 1939-09-12
Anticipated expiration: 1956-09-12

Description

Sept. 12, 1939. B. LAZICH ETAL ELECTRICAL RELAY Original Filed Jan. 14, 1930 4 Sh ets-Sheet 1 IN VENTORS Bvanlro Lazlch and By Haffg $12 zqol'zlz THEIR ATTORNEY Sept. 12, 1939. B. LAZICH ET AL ELECTRICAL RELAY Original Filed Jan.

14, 1930 4 Sheets-Sheet 2 Y R m m N w M g n i mzA A 0. LE 0 m Mm w T Y B u I Q 7"""""""" 1-1.x

Sept. 12, 1939. B. LAZICH El AL ELECTRICAL RELAY- Original Filed Jan. 14, 1930 4 Sheets-Sheet 3 s H h m Www H m MWA M 0 m wh E mm m BH Y B.

Sept. 12, 1939. B. LAZICH El AL ELECTRICAL RELAY Original Filed Jan. 14, 1930 4 Sheets-Sheet 4 INVENTORS Q12 f THEIR AHORN Bl'anlio Lazc'clz and yHarwy E.Aslzwarzfb Patented Sept. 12, 1939 UNITED STATES PATENT OFFICE worth, Swissvale, Pa.,

assignors to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Original application January 14, 1930, Serial No. 420,736, now Patent No. 1,966,965, dated July Divided and this application June 28, 1934, Serial No. 732,857

38 Claims.

Our invention relates to electrical relays, and particularly to relays of the type comprising a winding and a contact which is operated at the expiration of a time interval of predetermined length and of comparatively long duration after said winding becomes energized.

One object of our invention is to provide a relay of the type described in which the length of the time interval which elapses between the energization of its winding and the operation of its contact may be adjusted to any desired value.

Another object of our invention is to provide a relay of the type described which is so constructed as to provide maximum reliability of operation.

The present application is a division of our copending application, Serial No. 420,736, filed on January 14, 1930 Patent No. 1,966,965, dated July 1'7, 1934 for Electrical relay.

We will describe one form of relay embodying our invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a view, showing in side elevation, one form of relay embodying our invention, with certain of the parts omitted to illustrate the construction. Fig. 2 is a front view of the relay illustrated in Fig. 1. Fig. 3 is a rear view of the relay illustrated in Figs. 1 and 2. Fig. 4 is a top plan view of the neutral armature for the relay illustrated in Figs. 1, 2 and 3. Fig. 5 is a view showing, on a somewhat larger scale, the contact arm F for the relay illustrated in Figs. 1, 2 and 3, as it appears when viewed from the left in Fig. 3. Fig. 6 is a top plan view, drawn to the same scale as Fig. 5, of the contact arm for the relay illustrated in Figs. 1, 2 and 3. Fig. '7 is a fragmental view showing in isometric projection the magnetic clutch and drive shaft 26 forming a part of the relay illustrated in Figs. 1, 2 and 3. Fig. 8 is a detail view showing the pawl and ratchet mechanism for rotating the drive shaft 26 in response to oscillation of the auxiliary armature 21, as it appears when viewed from the right in Fig. 1. Fig. 9 is a diagrammatic view showing one circuit arrangement which may be used with the relay shown in Figs. 1, 2 and 3.

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

Referring first to Figs. 1, 2 and 3, the relay comprises a top plate A of suitable insulating material, such as porcelain or hard rubber, which serves as a support for all of the operating parts of the relay. Mounted on the top plate A are three

magnetizable cores

1, 2 and 3, the upper ends of which are connected together by a back strap 4, and the lower ends of which terminate, on the under side of the top plate A, in enlarged pole pieces,

l

2 and 3 respectively. Ihe core I is provided with a coil 5 and the core 2 is provided with a coil 8, each of which coils consists of two separate windings as will be explained more fully hereinafter. The core 3 is provided with a plurality of closed conductors. As here shown, these conductors comprise a sleeve 1 of suitable material such as copper, and a plurality of washers 8, also of suitable material such as copper.

A neutral armature 9 is pivotally supported for swinging motion toward or away from the pole pieces l and 2 on two pivot pins [9 threaded through the downwardly extending lugs of a non-magnetizable bracket 11 which is fastened to the sides of the pole pieces l and 2 by means of screws 12, as best seen in Fig. 1. As pointed out hereinafter, the armature 9 is at times operated by fluxes created by windings 5 and 6, and the windings are therefore so arranged that the fluxes produced thereby thread the armature 9 in the same directions. The fluxes from these windings will of course thread the core 3 in opposite directions. The opposite ends of the armature 9 are provided with ex tension 9 and 9' (see Fig. 4) which extensions cooperate with two auxiliary electromagnets B and C, respectively. These electromagnets are similar and, in the form here shown, and best illustrated in Figs. 1 and 2, each comprises a magnetizable core 2i extending downwardly from a magnetizable arm 22, and provided with a winding 23 and an elongated pole piece 24. The arm 22 of the electromagnet B is attached to the side of the pole piece 2 by means of screws 25, and the arm 22 of electromagnet C is similarly attached to the side of the pole piece l The parts of the electromagnets B and C are so arranged that when neutral armature 9 is swung away from the pole pieces 1 and 2 to its lower position in which it is illustrated in the drawings, the upper side of the pole piece 24 of electromagnet B will be parallel to, and will engage the underside of the extension 9 of armature 9, and the upper side of pole piece 24 of electromagnet C will be parallel to, and will engage the underside of the extension 9* of armature 9. The function of the electromagnets B and C will be explained in detail hereinafter.

A plurality of contact fingers, here shown as four in number, and designated l3, l4, l5, and

it, are attached to the under side of the armature 9 by means of insulating supports i'i. When armature 9 is swung away from the pole pieces l and 2 as shown in the drawings, the contact fingers l3, i l, and i5 each engage a back contact 58 to close contacts l3-l8, li-l8, and iii-i8, while the contact finger it engages a back contact is to close a contact iii-i 9. When armature 9 is swung towards the pole pieces l and 2 however, the contacts 53-48, l ii8, V-ifl, and l6l9 are all opened, and the contact finger it then engages a front contact 2'5 to close a contact l5'i5, while the contact finger it engages a front contact 20 to close a contact i62i3. The front contact 715 and the back con tacts l8 and i9 are attached to terminal posts i5 5 it and w respectively, mounted on the top plate A, as shown in Figs. 1 and 2, while the front contact 2i] is attached to a similar terminal post which is not shown in the drawings, but which is also mounted on top plate A.

As best seen in Figs. 1, 7 and 8, pole piece 3 of core 3 is bifurcated, and pivotally supported at its centre on a drive shaft 2% journaled in the bifurcations of pole piece 3 is an auxiliary armature ill. The pole pieces i and 2 have integral extensions 28 and 29, respectively, the pole faces of which overlie the armature El at its opposite ends. The armature 2i is arranged to swing toward one or the other of these pole faces, nonmagnetizable stops 3% (Fig. 8) being attached to the armature to prevent the armature from coming into actual contact with the pole faces.

The auxiliary armature 2'! is provided at one end with a contact finger 35 (Fig. 3) which is attached to the under side of the armature by means of an insulating support 32 and, at the other end, with a similar contact finger 33 which is simi arly attached to the armature by means of an insulating support When the armature 2? is swung toward the pole face of extension 23 of pole piece i as shown in the drawings, the contact finger 33 engages a fixed contact 35 fastened to a terminal post mounted on the top plate A, to close a normal contact 3S-35, and the contact finger 3i engages a fixed contact 36 attached to a terminal post also mounted on the top plate A, to close a normal contact 36-36. When armature 2'? is swung toward the pole face of ex tension 29 of pole piece 2 however, the contact finger 33 then engages a fixed contact Bl to close a reverse contact 3S3'i, and the contact finger 3i engages a fixed contact 38 to close a reverse contact s l33. The fixed contact 3'8 is attached to a terminal post St mounted on the top plate A, and the fixed contact 38 is attached to a similar terminal post also mounted on top plate A, but now shown in the drawings. While we have shown only two contact fingers attached to the armature 2? for simplicity in illustrating our invention, it is understood that additional contact fingers may be attached to this armature when desired.

As will be explained more fully hereinafter, the auxiliary armature it may at times be made to oscillate. When this armature is oscillating, the motion of the armature in one direction is transmitted to the drive shaft 26 by means of a pawl and ratchet mechanism (Figs. 1, 3, and 8), the pawl 39 being carried by a stud Gil projecting from the side of the armature 2i, and the ratchet wheel il being secured to one end of the drive shaft 26. The pawl 39 is normally held in engagement with the ratchet wheel at by gravity. Rotation of the drive shaft 26 in the direction opposite from that imparted to the drive shaft by the pawl and ratchet mechanism is prevented by a dog 52 of suitable resilient material secured to the underside of the extension 28 of the pole piece i and arranged to successively engage the teeth of the ratchet wheel ii as the wheel is rotated by the dog.

1 Mounted on the opposite end of the drive shaft ts from the ratchet wheel cl is a contact arm designated in general by the reference character F. As here shown, the contact arm F comprises two parallel plates 56 and ill secured together by spacing studs 33, as best seen in Figs. 1 and 5. The plate i is provided with two integral spaced lugs it and M3 and secured to a short shaft 56 which is journaled in these lugs is a worm 52'. The worm. iii meshes with a worm wheel 58, the hub 553 of which extends through, and is journaled in, a hole ri in the plate ll. Attached to the outer end of the hub 59 is a segment 60 which holds the worm wheel in place. The upper end 55 of the shaft 56 is made rectangular in shape to enable the shaft to be turned by a wrench or other suitable tool, and it will be apparent that when this shaft is turned, the worm Si rotates the worm wheel tit, thereby changing the position of the segment til with respect to the plates and ll. The segment Bil is provided with a scale, as best seen in Fig. 1, and the plate 47 has formed on its lower end a pointer ll which moves along this scale as the position of the segment with respect to the plates 46 and l": is varied. The reason for varying the relative position of the segment (36] and the

plates

43 and 3."! will be explained in detail hereinafter.

When the segment til has been adjusted to a predetermined position with respect to the plates 35 and it is desirable to hold the segment in this position and, for this purpose, we provide a locking member, here shown as a strip SI of flexible material, such as phosphor bronze. One end of the strip GE is fastened to the lug it by means of screws 82, and the other end of the strip is bent upwardly, and is provided with a rectangular slot i which is just wide enough to receive the upper end 58 of the short shaft 56 when the sides of the rectangular end are parallel to the sides of the slot Si With the parts of the arm F locked in this manner, when it is desired to change the position of the segment 68 with respect to the plates ii and 38, the inclined end of the strip iii is depressed as by the tool which is utilized for turning the shaft 56 until this end is below the rectangular end 56 of the shaft 56, whereupon the shaft 5% may be rotated until the segment 6i; occupies the desired position. It will be apparent that as soon as the tool is removed from the shaft, the free end of the strip 6! will automatically return to its inclined locking position provided the shaft occupies a position in which the sides of the end 56 are parallel to the sides of the slot fil The drive shaft extends through the hub E59 of the worm wheel iii. and through a hole 26 in the plate with sufficient clearance to permit the contact arm F to rotate about the drive shaft, and has attached to its outer end a pinion 43 which holds the contact arm on the drive shaft. The pinion '13 meshes with a gear wheel 3 i secured to one end of a countershaft 15. The countershaft i5 is journaled in suitable holes in the plates 46 and of the arm F, and carries on its other end a pinion (59 which meshes with a gear wheel Ell mounted on a bushing loosely journaled on the drive shaft The gear wheel 50 is attached to, or formed integral with, a clutch wheel 5| which, as here shown, is a knurled metal wheel, but which may, if desired, be constructed of any other suitable material, such for example, as cork, leather, or a condensation product of phenol. The clutch wheel 5| is at times engaged by a knurled stud 52 forming a part of a magnetic clutch which we will now describe.

This magnetic clutch, as best seen in Fig. '7, comprises a magnetizable member 53, pivotally supported on a pin 54 carried by a projection on one of the bifurcations of the pole piece 3 and arranged to be attracted toward the pole piece 3 and the extensions 28 and 29 of the pole pieces l' and 2 respectively, when either or both of the coils 5 and 6 are energized. The knurled stud 52 is attached to the lower end of the member 53 by means of a short strip 52 preferably of flexible material, and the parts are so arranged that when the magnetizable member 53 is attracted towards the pole piece 3 and the extensions 28 and 29, the stud 52 will engage the clutch wheel 5| and prevent rotation of the gear wheel 50. Two counterweights 55, attached to the upper part of the magnetizable member 53, bias this member to a position in which the stud 52 is out of engagement with the clutch wheel 5|.

The contact arm F is biased by gravity to a position in which an insulating strip 63 attached to the lug 46 engages a stop 13 fastened to a terminal post mounted on the top plate A as best seen in Fig. 3. When the arm occupies this position, the strip 63 also engages a contact finger 64 and moves it into engagement with a contact finger 65 to close a contact D. The contact finger 65 is attached to the terminal post 65 while the contact finger 64 is attached to a similar terminal post 64 also mounted on the top plate A. Suitable stops 66 are attached to the terminal posts 65 and 64 to limit the spacing between the contact fingers when the strip 63 is moved out of engagement with the contact finger 64.

The contact arm F also controls a contact E comprising two spaced contact fingers l6 and H attached by means of studs 68 to a block 61' of insulating material, which block, in turn, is fastened by means of a bracket 59 to a terminal post (:39 mounted on the top plate A. The contact finger '16 is provided with top and bottom stops ll] and 10 and the contact finger H is provided with a bottom stop H The contact E is arranged to be closed, in a manner which will be described in detail hereinafter, by an insulating piece 12 riveted to a lug 66* formed on the segment 6!! of the contact arm F.

Referring now to the wiring diagram for the relay shown in Fig. 9, the two windings of the coil 5 referred to hereinbefore are designated by the reference characters 5 and 5 respectively, and the two windings of the coil 6 are designated by the

reference characters

6 and 6*. Current is supplied to these windings and to the winding 23 of each of the auxiliary electromagnets B and C from a suitable source, such as a battery G, over a circuit controller H which may be operated in any suitable manner.

As shown in the drawings, circuit controller H is open so that windings 5 and 5 of coil 5,

windings

6 and 6 of coil 6, and windings 23 of the electromagnets B and C are all de-energized. The neutral armature 9 is therefore swung away from pole pieces l and 2 so that contacts I3-l 8, l4-l8, I5-l8, and l6-l9 are closed, while contacts I5-15 and l6-26 are open. Auxiliary armature 21 is swung toward extension 28 of pole piece I and normal contacts 33-35 and 3l-36 are therefore closed and reverse contacts 33-31 and 3l-38 are open. The contact arm F is held by gravity in its normal position, so that contact D is closed and contact E is open.

We will now assume that with the parts in the positions just described, circuit controller H becomes closed. Windings 5 5 6 and 6 are therefore connected in series with battery G over contact I5-l8, but only winding 6 becomes energized because windings 5 and 6 are short-circuited over a circuit which includes contact l3-l8, and winding 5 is short-circuited over a circuit which includes contacts I3-l8, I4-l8, and 3l-36. As a result, auxiliary armature 21 is swung toward extension 29 of pole piece 2 and the magnetizable member 53 of the magnetic clutch is attracted to the pole piece 3 and the extensions 28 and 29 of the pole pieces I and 2 The neutral armature 9, however, is held away from the pole pieces l and 2 under these conditions because the windings 23 of the auxiliary electromagnets B and C are deener'gized, and the reluctance of the path to the neutral armature through the magnetic structures of the auxiliary electromagnets B and C for the flux set up by the winding 6 is lower than the reluctance of the path to the neutral armature through the air gaps between the pole pieces I and 2 and the neutral armature, and more flux therefore reaches the neutral armature through the magnetic structure of the auxiliary electromagnets than through the air gaps between the pole pieces l and 2 and the neutral armature. It follows that the tractive force exerted to lift the armature 9 toward pole pieces l and 2 is less than the combined force of gravity and the effect of the flux through the magnetic structures of electromagnets B and C. The contacts l3-l8, !4-|8, 15-! and l6-l9 controlled by the neutral armature therefore remain closed even though winding 6 of coil 6 is now energized.

When the auxiliary armature 21 is swung towards extension 29 of pole piece 2*, the normal contacts 3l-36 and 33-35 controlled by this armature are opened, and the reverse contacts 3l-3B and 33-31 become closed. Since contacts l4-l8 and 15-!!! are still closed, the closing of reverse contact 3l-38 short-circuits winding 6 of coil 6, and the field set up by this winding commences to decay. Due, however, to the snubbing effect of the circuit for winding 6 and to the sleeve 1 and washers 8 on. the core 3, this decay is comparatively slow. The opening of the contact 3l-36 meantime has allowed winding 5 to become energized. The growth of the flux set up by this latter winding is comparatively slow, however, due to the sleeve 1 and washers 8 on core 3 but, after an interval of time, the torqueexerted on armature 21 by this fiux over-balances the torque exerted on armature 21 by the decaying flux in winding 6 and armature 21 then swings back toward extension 26 of pole piece l This motion first opens reverse contacts 3l-38 and 33-31 and then closes normal contacts 3l-36 and 33-35. The neutral armature 9 is still held away from the pole pieces l and 2 during this movement of the armature 21 for the reasons pointed out hereinbefore, so that contacts I3-l8, l4-l8, l5-l8, and Iii-l9 controlled by the armature 9 are still closed, and winding 6 therefore again becomes energized and winding 5 again becomes short-circuited. The field of winding l5 then slowly builds up and the field of winding 5" slowly decays, this decay being retarded by the self-inductance of winding 5*, and by sleeve 3, and the Washers 8. It will therefore be clear that auxiliary armature 2'! is positively swung to and fro as long as cir-- cuit controller H is closed and the winding 23 of the auxiliary electromagnets B and C remain deenergized, and it will also be clear that a considerable interval of time elapses between armature movements. It should be pointed out that this time interval is substantially independent of fluctuations of the electrornotive force in the energy supply because the auxiliary armature is acted upon by two opposing forces both of which increase or decrease as the electromotive force of the energy supply increases or decreases. This time interval, however, may be varied by varying the rate at which the flux in core 3 builds up or decays, this variation being effected, with the apparatus constructed in the manner here shown, by Varying the number of Washers 8 on core 3.

Each time auxiliary armature 21 is swung towards pole piece 29, drive shaft 26 is rotated through a small arc due to the pawl and ratchet mechanism described hereinbefore. This rotation of the drive shaft 26 is transmitted through the pinion 43 to the gear wheel M which, in turn, drives pinion 69. Since the magnetizable member 53 is now swung towards pole piece 3 and the extensions 28 and 29 of the pole pieces l and 2 gear Wheel 58 is prevented from rotating by the engagement of knurled stud 52 with the clutch wheel 5!, and it will be apparent, therefore, that the pinion 43, gear wheel 44, pinion 49, and gear wheel 56 constitute a planetary drive by means of Which contact arm F is rotated around the drive shaft 26 as a pivot, the direction of such rotation being clockwise as seen in Fig. 3. As soon as the contact arm has been rotated through a small arc, the resultant movement of the insulated strip 63 permits contact finger 64 to move out of engagement with contact finger 65, thereby opening contact D; and, when the arm has been rotated through a sufficiently large arc, the insulating piece 12 attached to segment 66 engages contact finger H and moves it into engagement with contact finger '56, thereby closing contact E.

When contact E becomes closed, current from battery G is supplied to the windings 23 of the electromagnets B and C in series if contact 3 4-35 is closed, or if this contact is not closed, then on the next operation of armature 21 which closes this contact, the circuit for these windings including, in addition to contact E and contact 3!-36, contact 14-18 and circuit controller H, as will be apparent from an inspection of, Fig. 9. The windings 23 are connected in this circuit in such manner that the fluxes created in the cores 2| of the auxiliary electromagnets B and C by the current in these windings thread the cores BE in the opposite direction from the flux which threads these cores due to current in either of the windings 5 and 6 and the parts are so proportioned that the magnitude of the flux in the cores 2! due to the current in the windings 23 is sufficiently great that the flux which threads the armature 9 through the air gaps bet veen the armature 9 and the pole pieces I and 2 under these conditions will exert a torque on the armature which causes the armature to swing toward the pole pieces l and 2 Shortly after the armature 9 starts to swing toward the pole pieces I and 2 contacts l4i8, l5i8, and l6-l9 are pened, but contact l3-l8 is adjusted to remain closed until the armature has moved a short distance beyond the point in its upward travel at which the contacts I l-48, l5lii, and l6-l9 open. When contacts l4l8 and Iii-48 are opened, winding 6 which is normally energized When these contacts are closed and contact 3l-36 is closed, becomes de-energized and, at the same time, the short circuit which is normally completed for winding 5" at contact |4|8 when contact 3l36 is closed, is opened. Winding 5" is then supplied with current in series with the windings 23 of the electromagnets B and C over contact [3-48 which, as pointed out hereinbefore, remains closed after contacts l4l8 and l5l8 are opened, and winding 5 therefore becomes energized and supplies flux to the armature 9 in place of winding 5 The resistance of the windings 23 will usually be considerably less than the resistance of the winding 5 so that the magnitude of the flux which is supplied to armature 9 due to the current in Winding 5 under these conditions will be only slightly less than the magnitude of the flux which was supplied to the armature 9 due to current in, winding 6, and it will be apparent, therefore, that the opening of contacts Hll8 and I5-i8 has very little effect on the torque exerted on the armature tending to move the armature toward the pole pieces I and 2 As soon as winding 6* becomes de-energized and Winding 5 becomes energized in the manner just described, auxiliary armature 27 stops oscillating and this armature is then held in the position in which its normal contacts 3l-36 and 3335 are closed. the short circuit which was previously closed for windings 5 and W at this contact, is opened, and the windings 5 5 6 and 23 in series are then all supplied with current from battery G over contact E and circuit controller H, so that these windings are all energized. The windings 5 and 6 are preferably constructed to have a comparatively high resistance in order to limit to a low value the current supplied to the relay from battery G- after these windings become ener gized. When armature 9 has completed its upward stroke contacts [El-15 and lfi-2U become closed. As long as circuit controller H now remains closed the windings 5 5 6 and 23 will continue to be energized because the magnetic clutch is held in the position in which the stud 52 engages the clutch wheel 5!, so that the contact arm F is held in the position in which contact E is closed. It will be apparent, therefore, that after the neutral armature has once been attracted to the pole pieces l and 2 this armature will be held in the position which it then occupies until circuit controller H is opened to de-energize the relay. When this is done, the neutral armature 9 drops away from the pole pieces l and 2 thereby opening contacts |5l5 and l52fi, and closing contacts i3l3, M-l8, l5-l8 and l6l9. Furthermore, the magnetic clutch drops away from the pole piece 3 and the extensions 28 and 29 of the pole pieces l and 2 respectively, thereby permitting the contact arm to return by gravity to its normal position. When the contact arm returns to its normal position, contact E is opened and contact D becomes closed. When contact D becomes closed, the parts of the relay are then restored to their normal positions in which they are illustrated in the drawings.

It will be noted in Fig. 9 that when armature 9 is picked up, winding 6 is short-circuited by When contact l3l8 opens,

contact l515. As a result, when the relay becomes de-energized, the self-inductance of winding Ii retards the decay of flux which threads the neutral armature, and hence causes the neutral armature to be slow-releasing. Under some conditions it may be desirable to cause the neutral armature to release more quickly upon the de-energization of the relay and, when this is the case, this contact may be omitted.

The time interval which elapses between the energization of the relay and the closing of contact E depends upon the rate at which armature 21 oscillates, upon the gear ratios of the tary drive for the contact arm F, and upon the length of the are through which the contact F must rotate from its normal position before insulating piece 12 closes contact E. The rate at which armature 21 oscillates may be varied by varying the proportioning of the parts, and by varying the number of washers 8 on core 3, as pointed out hereinbefore; the gear ratios of the planetary drive may be varied by replacing the gear wheels with other gear wheels having the desired ratio, as will be readily understood; and the length of the are through which the contact arm F has to move from its normal position in order to close contact E may be varied by varying the relative position of the segment 60 with respect to the

plates

46 and 47 in the manner which has also been previously described. It will be apparent, therefore, that the time interval which elapses between the energization of the relay and the closing of contact E may be adjusted to any desired value.

For any given gear ratio and proportioning of the parts the time interval required for the operation of the relay may be indicated by the position of the pointer 41 on the scale which is provided on segment 60 by suitably calibrating this scale so that the graduations on this scale correspond to the correct time intervals.

It is desirable that adjustments in the length of the time interval which elapses between the energiz'ation of the relay and the closing of contact E due to changes in the position of the segment 60 with respect to the

plates

46 and 4! of the contact arm F may be made from the top of the relay and, for this purpose, we provide a bushing 12 which is mounted in the top plate A in such manner that the bushing is directly above the vertical shaft 56 when the contact arm occupies its normal position, as shown in Fig. 3. The upper end of this bushing is threaded to receive a nut 12*, by means of which the top of the bushing may be closed. With the parts constructed in this manner, when it is desired to change the position of the segment 60 with respect to the

plates

46 and 41 of the arm F, the nut li removed from the top of the bushing, and the shaft 56 is turned by a suitable tool inserted through the bushing 12.

The contact D serves as a check to indicate that the contact arm F has returned to its normal position when the relay becomes de-energized. This contact may be used to control any suitable form of indicating apparatus in any suitable manner.

The normal contact 33-35 and reverse contact 33--3l controlled by the auxiliary armature 2?, and the contacts l$-l3 and Iii-2 3 controlled by the neutral armature may be utilized to control any desired circuits in any suitable manner forming no part of our present invention and therefore not shown in the drawings.

From the foregoing, it will be apparent that we have provided a time element relay in which a definite time interval of adjustable length and of. comparatively long duration may be made to elapse between the energization of the relay and the closing of contact E.

One advantage of a relay embodying our invention is that, since the contacts Iii-I8, [4-48 and l5-l8 are included in the circuits over which current is supplied to the windings of the relay before contact E becomes closed, the neu tral armature is positively prevented from picking up until this contact becomes closed. For, if, due, for example, to vibration or to some fault in the magnetic structure of the auxiliary electromagnets B and C, or to excessive voltage supplied to either or both of the windings 5 and 6 the neutral armature starts to move toward the pole pieces i an E before contact E becomes closed, then, as soon as the motion of the armature starts, the contacts l4!8 and l5l8 open and deenergize the winding 5 or 6 which is then energized, so that the armature 9 immediately returns to its lower position.

Another advantage of a relay embodying our invention is that due to the construction and arra ngement of the parts a high degree of accuracy in the time required for the operation of contact E is obtained.

Still another advantage of a relay embodying our invention is that the relay is constructed with a minimum of parts arranged to provide maximum reliability of operation.

Although we have herein shown and described only one form of relay embodying our 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 our invention.

Having thus described our invention, what we claim is:

1. In combination, three magnetizable cores connected together at one end by a back strap, a first coil on a first one of said cores and a second coil on a second one of said cores, a first armature pivotally attached to a third one of said cores and arranged to swing toward said first core or said second core, means controlled by said first armature for at times energizing said coils in such manner that said first armature is oscillated, a contact, means responsive to a predetermined number of oscillations of said first armature to operate said contact, a second armature arranged to at times swing toward said first and said second cores when said first or said second coil is energized, and means for preventing said second armature from swinging toward said first and said second cores unless said contact is operated.

2. In combination, a magnetic circuit including an armature, a first winding for creating flux in said magnetic circuit, a branch for said magnetic circuit including said armature, and a second winding for at times creating flux in said branch which opposes the fiux in said branch due to the first mentioned means.

3. In combination, a magnetic circuit including an armature, a first winding for creating flux in said magnetic circuit, a branch for said magnetic circuit including said armature, and a second winding for at times creating flux in said branch which threads said branch in the opposite direction from and which has a magnitude equal to or greater than the flux in said branch due to flux in said magnetic circuit.

4. In combination, an electromagnet, an armature movable toward and away from said electromagnet, means for creating fiux in said electromagnet, an auxiliary path from said electromagnet to said armature having a lower reluctance when said armature is away from said electromagnet than the path to said armature through the air gaps between said armature and said electromagnet for at times supplying fiux to said armature from said lectromagnet in such man ner that said armature is normally held away from said electromagnet, and means for at times creating fiux in said auxiliary path which allows said armature to move toward said electromagnet.

5. In combination, an eleotromagnet, an armature movable toward and away from said electromagnet, means for at times creating flux in said electromagnet, a magnetic path from said electromagnet to said armature having a lower reluctance when said armature is swung away from said electromagnet than the reluctance of the air gaps between said armature and said electromagnet for at times supplying fiux from said electromagnet to said armature such manner that said armature is normally held away from said electromagnet, and means for at times creating flux in said magnetic path which opposes the flux in said path due to the fiux in said electromagnet to an extent which permits said armature to move toward said electromagnet.

6. In combination, two main magnetizable cores connected together at one end by a back strap, a pivoted armature controlled by said cores and biased to a normal position in which said armature is separated from said cores by air gaps, a first and a second extension on said armature one integral with each end of said armature, a first and a second auxiliary electromagnet each comprising a magnetizable core carried by a magnetizable arm and provided with a winding, means for attaching the magnetizable arm of said first auxiliary electromagnet to a first one of said cores and for attaching the magnetizable arm of said second auxiliary electromagnet to the other said core, a first elongated pole piece attached to the core of said first auxiliary electromagnet in such manner that said first elongated pole piece engages the underside of said first extension when said armature occupies its normal position, a second elongated pole piece attached to the core of said second auxiliary electromagnet in such manner that said second elongated pole piece engages the underside of said second extension when said armature occupies its normal position, a first and a second coil one on each said main core, means for at times supplying current to said coils to create a flux in said main cores, and means for at times supplying current to the windings of said auxiliary electromagnets in such manner that the flux set up in the cores of said auxiliary electromagnets by the current in said windings opposes the fiux which threads the cores of said auxiliary electromagnets due to current in said first and second coils.

I 7. In combination, a first, a second, and a third magnetizable core connected together at one end by a back strap, a first pole piece on the free end of said first core and a second pole piece on the free end of said second core, a bifurcated pole piece on the free end of said third core, two extensions, one for each of said first and second pole pieces, a drive shaft journaled in the bifurcations or said bifurcated pole piece, an oscillatable armature pivoted on said drive shaft between said bifurcations and arranged to swing toward one or the other of said extensions, a conducting sleeve on said third core, a first winding on said first core and a second winding on said second core, means controlled by said armature for supplying said first winding with current and for short-circuiting said second winding when said armature is swung toward said second pole pi ce and for supplying said second winding with current and for short-circuiting said first winding when said armature is swung toward said first pole piece, whereby said armature is'made to oscillate, means for rotating said drive shaft through a small arc each time said armature is swung toward said first pole piece, a contact, and a contact arm journaled on said drive shaft and biased to one position and provided with means controlled by said shaft and by both said indings for rotating said arm from said one position through a predetermined distance to operate said contact upon the expiration of a predetermined time interval after said armature starts to oscillate.

8. In combination, three magnetizable cores connected together at one end by a back strap, a neutral armature arranged to swing toward and away from said cores, a first coil on a first one of said cores and a second coil on a second one of said cores, an auxiliary armature pivotally attached to the third one of said cores and arranged to swing toward said first or said second core, means controlled by said auxiliary armature for at times energizing said first and second coils in such manner that said auxiliary armature is oscillated, an auxiliary path from said first and second cores to said neutral armature having a lower reluctance when said neutral armature is swung away from said first and second cores than the path to said neutral armature through the air gaps between said first and said second cores for at times supplying fiux to said neutral armature from said cores in such manner that said neutral armature is at times held away from said cores, a contact arm which is rotated through a small are for each oscillation of said auxiliary armature, and means controlled by said contact arm and efiective when said contact arm is rotated through a predetermined angular distance for creating flux in said auxiliary path of such a magnitude and direction that the flux supplied to said neutral armature from said first and said second coils through the air gaps between said armature and said first and said second cores causes said neutral armature to swing toward said first and said second cores.

9. In combination, three magnetizable cores connected together at one end by a back strap, a neutral armature arranged to swing toward and away from said cores, a first coil on a first one of said cores and a second coil on a second one of said cores, an auxiliary armature pivotally attached to the third one of said cores and arranged to swing toward said first or said second core, means controlled by said auxiliary armature for at times energizing said first and second coils in such manner that said auxiliary armature is oscillated, an auxiliary path from said first second cores to said neutral armature having a lower reluctance when said neutral armature is swung away from said first and second cores than the path to said neutral armature through the air gaps between said first and said second cores for at times supplying fiux to said neutral armature from said cores in such manner that said neutral armature is at times held away from said cores, a contact arm which is rotated through a small are for each oscillation of said auxiliary armature, means controlled by said contact arm and effective when said contact arm is rotated through a predetermined angular distance for creating flux in said auxiliary path of such a magnitude and direction that the fiux supplied to said neutral armature from said first and said second coils through the air gaps between said armature and said first and said second cores causes said neutral armature to swing toward said first and said second cores, and means effective when said neutral armature is swung toward said first and second cores for energizing both said first and said second coils in such manner that said auxiliary armature stops oscillating.

10. A relay comprising two windings, means for alternately energizing said windings, a contact which is operated when said windings have been alternately energized for a predetermined length of time, and means controlled by said contact for de-energizing one of said windings.

11. A relay comprising two windings, means for alternately energizing said windings, an armature which is oscillated when said windings are alternately energized, a contact which is operated when said armature has been oscillated a predetermined number of times, and means controlled by said contact for de-energizing one of said windings to prevent further oscillation of said armature.

12. A relay comprising two windings, means for alternately energizing said windings, a contact which is at times operated by said windings, means for preventing operation of said contact until after said windings have been alternately energized for a predetermined length of time, and means controlled by said contact for de-energizing one of said windings.

13. A relay comprising two windings, means for alternately energizing said windings, a first contact which is at times operated when one of said windings is energized, a second contact which is operated when said windings have been alternately energized for a predetermined length of time, means for preventing operation of said first contact until after said second contact has been operated, and means effective when said first contact has been operated for deenergizing said one winding.

14. A relay comprising a first, a second, and a third winding, means for alternately energizing said first and said second winding, a first contact which is operated when said first and said third winding are both energized, a second contact which is operated when said first and second windings have been alternately energized for a predetermined length of time, means controlled by said second contact for energizing said third winding, and means effective when said first contact is operated for de-energizing said first wind- 15. A relay comprising six windings, means for alternately energizing a first and a second of said windings, three normally closed contacts two of which are opened when said first winding and a third and fourth of said windings are all energized, the remaining normally closed contact being arranged to open after said second and third contacts are opened, a fourth contact which is closed when said first and second windings have been alternately energized for a predetermined length of time, means for energizing said third and fourth windings in series when said second and fourth contacts are closed, means for deenergizing said first winding when said second contact is subsequently opened, means for energizing said second, third, and fourth windings in series when said second and third contacts are opened and said first and said fourth contacts are closed, and means for energizing the remaining two windings and said second, third, and fourth windings in series when said first contact is opened and said fourth contact is closed.

16. In combination, three magnetizablc cores connected together by a back strap, a first coil on a first one of said cores comprising a first and a second winding, a second coil on a second one of said cores comprising a third and a fourth winding, a neutral armature biased to a normal position in which said armature is separated from said first and second cores by air gaps and arranged to be swung at times toward said first and second cores, two magnetic paths one from each of said cores to said neutral armature, said paths having a lower reluctance when said armature occupies its normal position than the paths to said armature through the air gaps between said armature and said cores, a fifth winding on one of said paths and a sixth winding on the other of said paths, three normally closed contacts operated by said neutral armature, a first and a second of which are arranged to be opened upon a certain movement of said neutral armature away from its normal position and the third of which is arranged to be opened upon a further movement of said neutral armature away from its normal position, an auxiliary armature pivotally attached to the third one of said cores and arranged to swing toward said first or said second core, a fourth contact which is closed when said auxiliary armature is swung toward said first core and a fifth contact which is closed when said auxiliary armature is swung toward said second core, a source of electromotive force, means including said second contact for connecting said first, second, third, and fourth windings in series with said source, means for short-circuiting said second and fourth windings when said third contact is closed, means for short-circuiting said first winding when said third, first and fourth contacts are closed, means for short-circuiting said second winding when said first, second, and fifth contacts are closed, whereby said auxiliary armature is oscillated, a sixth contact which is closed when said auxiliary armature has been oscillated for a predetermined number of times, means for connecting said fifth and sixth windings in series with said source, when said sixth, first, and fourth contacts are closed, said fifth and sixth windings being so arranged and so proportioned that when said fifth and sixth windings are connected in series with said source the flux which is supplied to said neutral armature from said cores through the air gaps between said armature and said cores exceeds that supplied to said armature through said magnetic paths, whereby said neutral armature is moved toward said cores, and means including said sixth and said third con tact for connecting said first, fifth and sixth windings in series with said source after said second and third contacts are operated.

17. In combination, three magnetizable cores connected together at one end by a back strap, a first coil on a first one of said cores and a second coil on a second one of said cores, an armature pivotally attached to a third one of said cores and arranged to swing toward said first core or said second core, means for energizing said coils in such manner that said armature is oscillated, and a plurality of washers of electro-conducting material on said third core for controlling the speed at which armature is oscillated when said coils are energized.

18. In combination, three magnetizable cores connected together at one end by back strap, a first coil on a first one of said cores and a second coil on a second one of said cores, an armature pivotally attached to a third one of said cores and arranged to swing toward said first core or said second core, means for energizing said coils in such manner that said armature is oscillated, and a plurality of washers of electro-conducting material on said third core the number of which washers may be varied to vary the speed at which said armature is oscillated when said coils are energized.

19. In combination, three magnetizable ccrc connected together at one end by a back strap, a neutral armature arranged to swing toward and away from said cores, a first coil on a first one of said cores and a second coil on a second one of said cores, an auxiliary armature pivotally attached to the third one of said cores and arranged to swing toward said first or said second core, means controlled by said auxiliary armature for at times energizing said first and second coils in such manner that said auxiliary armature is oscillated, an auxiliary path. from sai' first and second cores to said neutral armature having a lower reluctance when said neutral armature is swung away fromv said first and second cores than the path to said neutral armature through the air gaps between said first and said second cores for at times supplying flux to said neutral armature from said cores in such manner that said neutral armature is at times held away from said cores, a contact arm which is rotated through a small are for each oscillation of said auxiliary armature, means controlled by said contact arm and effective when said contact arm is rotated through a predetermined angular distance for creating flux in said auxiliary path of such magnitude and direction that the fiux supplied to said neutral armature from said first and said second coils through the air gaps between said armature and said first and second cores causes said neutral armature to swing toward said first and said second cores, and a contact which is operated when said neutral armature is swung toward said first and second cores.

20. In combination, three magnetizable cores connected together at one end by a back strap, a first coil on a first one of said cores and a secand coil on a second one of said cores, an armature pivotally attached to a third one of said cores and arranged to swing toward said first core or said second core, means for energizing said coils in such manner that said armature is oscillated, and means associated with said third core for controlling the speed at which said armature is oscillated when said coils are ener gized.

21. In combination, three magnetizable cores connected together at one end by a back strap, a first coil on a first one of said cores and a second coil on a second one of said cores, an armature pivotally attached to a third one of said cores and arranged to swing toward said first core or said second core, means for energizing said coils in such manner that said armature is oscillated, and means on said third core for varying the rate at which the fiux which is set up in said third core due to the energization of said coils builds up and decays to vary the speed at which said armature is oscillated.

22. In combination, three magnetizable cores connected together at one end by a back strap, a first coil on a first one of said cores and a second coil on a second one of said cores, an armature pivotally attached to a third one of said cores and arranged to swing toward said fint core or said second core, means for energizing said coils in such manner that said armature is oscillated, and a plurality of conductors on said third core for controlling the speed at which said armature is oscillated when said coils are energized.

23. In combination, three magnetizable cores connected together at one end by a back strap, a first coil on a first one of said cores and a second coil on a second one of said cores, an armature pivotally attached to a third one of said cores and arranged to swing toward said first core or said second core, means for energizing said coils in such manner that said armature is oscillated, and means on said third core for delaying the rate at which the fiux which is set up in said third core due to the energization of said coils builds up and decays.

2 1. In combination, three magnetizable cores connected together at one end by a back strap, a first coil on a first one of said cores and a second coil on a second one of said cores, an armature pivotally attached to a third one of said cores and arranged to swing toward said first core or said second core, means for energizing said coils in such manner that said armature is oscillated, and a closed conductor on said third core for delaying the rate of growth and decay of the flux which is set up in said third core due to the energization of said coils.

25. In a contact operating mechanism, a neutral armature, two U-shaped electro-magnetic actuating means, each having a common leg, and means for equally adjusting the inductive characteristics of said two electro-magnetic actuating means, said means including short circuited windings on said common leg.

26. In a contact operating mechanism, a neutral armature, one magnetic circuit for actuating said armature, another magnetic circuit for actuating said armature, said magnetic circuits being in one part common to each other, and energizing means for each of said magnetic circuits connected to cause magnetic fiuXes to flow in said magnetic circuits in directions such that the fluxes will fiow in opposite directions in said one common part.

27. In a contact operating mechanism, a neutral armature, one magnetic circuit for actuating said armature, another magnetic circuit for actuating said armature, said magnetic circuits being in one part common to each other, energizing means for each of said magnetic circuits connected to cause magnetic fluxes to flow in said magnetic circuits in directions such that the fiuxes will flow in opposite directions in said one common part, and means for equally adjusting the inductive characteristics of said magnetic circuits, said means including short circuited windings associated with said one common part.

28. In a contact operating mechanism, a pivoted neutral armature, two electro-magnets one on each side of the pivotal axis of said armature whereby the armature is swung in one direction or the other according as one or the other of said electro-magnets is energized, said electromagnets being in one part in common with each other, and means energizing said electro-magnets alternately, said means so effective as to cause magnetic flux to flow in said common part in opposite directions when one or the other of said electro-magnets is energized, whereby upon the energization of one of said electro-magnets immediately following the deenergization of the other of said electro-magnets the response of said armature to said one electro-magnet is retarded.

29. In a contact operating mechanism, a neutral armature pivoted substantially at the center of its axis, three substantially parallel core members, one of said core members located at one end of said armature, another of said core members located at the other end of said armature, a third core member located substantially over the center of said armature, back strap means connecting said core members at their ends farthest from said armature, and two windings, one on said core member, another on said other core member.

30. A relay comprising a core having three legs, an armature pivotally supported to swing toward one or the other of the outer legs, a winding on each outer leg, energizing means for each of said windings connected to cause magnetic fluxes to flow in opposite directions in the middle leg, and means operating when said armature is swung to either outer leg to place the winding on such leg on short circuit.

31. A relay comprising a pivoted armature, two electro-magnets, one on each side of the pivotal axis of said armature whereby the armature is swung in one direction or the other according as one magnet or the other is energized, means effective when said armature is swung toward either magnet to place the winding of such magnet on short circuit, and energizing means for said electro-magnets to cause the fluxes through the wind ings of the electro-magnets to flow respectively in opposite directions.

32. In a contact operating mechanism, a neutral armature, two electro-magnets, each having a common leg, and adjusting means for equally adjusting the inductive characteristics of said electro-magnets, said means including said common leg,

33. In a contact operating mechanism, a neutral armature, one magnetic circuit for actuating said armature, another magnetic circuit for actuating said armature, said magnetic circuits being in one part common to each other, energizing means for each of said magnetic circuits connected to cause magnetic fluxes to flow in said magnetic circuits so that the fluxes will flow in said one common part, and means for equally adjusting the inductive characteristics of said magnetic circuits, said means including short circuited windings associated with said one common part.

34. In a contact operating mechanism, a pivoted neutral armature, two electro-magnets one on each side of the pivotal axis of said armature whereby the armature is swung in one direction or the other according as one or the other of said electro-magnets is energized, said electromagnets being in one part in common with each other, and means controlled by said armature for energizing said electro-magnets alternately, said means so effective as to cause magnetic flux to flow in said common part in opposite directions when one or the other of said electromagnets is energized, whereby upon the energization of one of said electro-magnets immediately following the deenergization of the other of said electro-magnets the response of said armature to said one electro-magnet is retarded.

35. In a contact operating mechanism, a neutral armature, two Ushaped electro-magnetic actuating means, each having a common leg, means for alternately energizing said electromagnets, and means for equally adjusting the inductive characteristics of said two electromagnetic actuating means, said means including short circuited windings on said common leg.

36. In a contact operating mechanism, a neutral armature, two U-shaped electro-magnetic actuating means, each having a common leg, means controlled by said armature for alternately energizing said electro-magnets, and means for equally adjusting the inductive characteristics of said two electro-magnetic actuating means, said means including short circuited windings on said common leg.

37. In contact operating mechanisms, in combination, an armature, two U-shaped electromagnetic actuating means for the armature, each having a common leg, and a short circuited winding on the common leg for equally adjusting the inductive characteristics of the two actuating means,

38. In contact operating mechanisms, in combination, a movable armature, two U-shaped electro-magnetic actuating means for the armature, each having a common leg, and a means on the common leg for equally adjusting the magnetic characteristics of the two actuating means.

BRANKO LAZICH. HARRY E. ASHWORTI-I.