Патент USA US2135490код для вставки
Nov. 8, 1938. E. o. BLODGETT 2,135,490 RELAY Filed July 28, 1934 5 $heets—Sheet l FIG-.1. 15 1a 14 a 44 H 10 17 as a? 2434 . 1,5 55 35 11 35 12 g 25 -\ \ I 4546 55 43 37 10 25 .v B V1 ‘ E M m NV ATTORNEY Nov. 8, 1938. I E, Q, BVLODGETT RELAY 2,135,490 ' Filed July 28, 1934 3 Sheets-Sheet 2 m ""'__|||IT 55 » [mill] // 17 as 34 52 1 36 11 : g; I 19 - 12 4° _ I 22 2: E 20 — >19‘ - 18 2 2 ‘ 52 , 272526 22 1 :2 . 2a 9 275/121; "45\50 Q7 10 2a26 04.5 546 4a. 25 27 INVENTOR 5.0. M! “MM ATTORNEY , ’ Patented Nov. 8, 1938 2,135,4t-i i : UNITED STATES PATENT OFFICE 2,135,490 RELAY ‘ Edwin 0. Blodgett, Rochester, N. 'Y., assignor to General Railway Signal Company, Rochester, N. Y. Application July 28, 1934, Serial No. 737,440 24 Claims. This invention relates to relays, and more par ticularly to a tractive type relay which is self compensating to allow its armature to be re leased from its attracted position in response to an‘abrupt decrease in energization of the relay with the same certainty regardless of the degree ‘of energization which had gradually obtained previously » In a normally energized track circuit, it is es sential to attract the armature of the track re lay associated therewith and to hold the arma ture in its attracted position during normal ly unoccupied conditions from current passing through the rails of the insulating section of trackin series, but when the section becomes occupied, the train must shunt sui‘?cient cur rent through the wheels and axles to effect the release of the relay armature. Obviously, then, the leakage of the current from one rail to the other throughout the track section af fects the armature of the track relay in the (Cl. 246-41) leased position, and it is also proposed to incor porate a simple and reliable means for manu ally adjusting the magnitude of the armature retaining force'which is to thus be maintained constant regardless of subsequent gradual varia tions in energization, and to provide such an adjustment which will not a?ect the magnitude of the force by which the armature is attracted from its released position. Other objects, purposes and characteristic fea tures of the present invention will be obvious as the description thereof progresses, during which, references will be made to the accom panying drawings, in'which— Fig. 1 diagrammatically shows a preferred form 15 of the present invention applied to a normally energized railway track circuit. Fig. 2 is a front elevational sectional view of a relay incorporating a preferred embodiment of the present invention. Fig. 3 is a side elevational sectional View of the same manner as the shunt effected by a train, relay shown in Fig 2. and consequently it is found that when the track circuit current is adjusted to a .value permit ting proper ‘operation at any one time, a change in weather condition may in one instance su?i Fig. 4 is a partial bottom View of the relay shown in Fig. 2 with the armature and certain ciently, increase the current leakage between rails to‘ duplicate the effect of a train shunt and drop the usual type of track relay, or in an other parts removed. 7 Fig. 5 is a plan view of a detail of the relay shown in Fig. 2. Fig. 6 is a partial front elevational sectional view showing a modi?cation which may be made other instance the leakage current may sufficient ly decrease to increase the relay energization to such an abnormally high value that the relay in the relay shown in Fig. 2. particularly adapted to produce reliable opera In the drawings/the present invention has been shown‘as applied to a relay constructed Fig. '7 is a side elevational view of a relay in corporating a modi?ed form of the present in armature will not release in response to a train vention with certain parts of the relay sectioned shunt. and other parts removed. In view of the above and other considerations, * Fig. 8 is a front elevational view of the relay it is proposed in accordance with the present in shown in Fig. 7, also having certain parts sec vention to provide a self-compensating relay tioned. tionunder various special conditions, such as 40 encountered in a track circuit, to which the conventional type of tractive relay is not par ticularly adapted. Speci?cally, it is proposed to provide a relay of the tractive armature type which is self~compensating to maintain a con “ stant tractive force acting on its armature when in its attracted position regardless of changes which occur gradually in the energization ofv the relay to thereby allow the armature to drop away’ in response to an abrupt reduction in energization with equal certainty regardless of the degree of e-nergization which had previously obtained gradually. It is further proposed to provide a locking means actuated by a release of the armature to prevent the above compensat ing action as longas the armature is in its re along the lines of the type found suitable for 40 railway signalling systems and particularly for railway track circuits, but it will be obvious that the present invention can equally well be ap plied to various other well known relay types. 4 The general construction of the relay shown in detail includes two vertical cores 1 and 8 hav ing enlarged lower ends forming pole faces 9 and Ill, respectively, whereby they are held to a top plate II by screws l2, the top plate it being of insulating or at least non-magnetic ma terial. The cores 1 and 8 carry windings I3 and M, respectively, which are normally con nected in series and arranged to produce cumu lative ?ux within the cores 1 and 8, which cores 55 2 2,135,490 are joined at their upper ends by a yoke l5 of magnetic material held thereto by bolts I6. A tractive type magnetic armature I1 is piv otally supported below the lower surface of the pole pieces 9 and It so as to be attracted thereto and complete the magnetic circuit by energiza tion of the coils I3 and M, the armature ll be ing biased away from the pole pieces 9 and ill by gravity. The armature supporting means Boom 10 prises a non-magnetic yoke l8 (see Fig. 4) sus pended from the top plate II by bolts l9 each attached to the top plate II by nuts 20 bear ing on spacing bushings 2|, the yoke l8 being carried between upper and lower nuts 22 .to threaded only at its upper end, the lower end forming a bearing for the shaft 33 andis pro vided with an annular upper ?ange retained in a recess in the top of the plate H by a cover plate 35 secured above the plate H by screws 36 as shown in Fig. 5. The shaft 33 is rotated to various positions in accordance with the magnetomotive force ob taining between the pole pieces 59 and I'll by an armature 31 suitably attached thereto and hav—' 10 ing enlarged circular ends, these circular ends coacting with curved inner vertical surfaces of the pole pieces 9 and ID as shown in ‘Fig. 4, the armature .37 being shown in all the present ?g 15 thereby be vertically adjustable along the end ures .as assuming -a position in response to a 15 portions of the bolts 19. ‘Two armature arms 23 are suitably attached to the armature H and maximum value of magnetomotive force which would normally obtain in the relay. The arma ture-31 thus being separated by a small air gap from the vertical surface of the pole pieces 9 and it tends to rotate to a position aligning with the 20 adjustably hold outwardly extending trunnion pins 25 by screws 26, which trunnion ,pins have reduced ends rotatably ?tting into holes in. down wardly extending lugs ‘21 carried by the yoke I8. The armature :l"! is thus adjustably sup ported to permit pivotal movement relative to the pole faces 9 and ID with a minimum of ‘fric 25 tion. - Suitable contacts are, of course, ‘attached to the armature I‘! in a manner to engage either upper or lower ‘fixed ‘contacts in. accordance .of the pole pieces 9 and 10., all .of which is .in accordance with well known principles of mag with the operation of the armature, ‘but to sim netic attraction. 30 plify the present disclosure such contact means have been omitted from all views, except Fig. 3 which shows in a very diagrammatic ‘manner a movable contact ?nger 28 attached to the arma ture I’! by insulating spacing screws 7,29, and this 35 movable ?nger 28 engages either front or back fixed contacts indicated merely by ‘the arrows in. Fig. 3. vIn a tractive type relay, such as just described, it is well known that the force retaining the ar mature in its attracted position against the pole pieces is substantially proportional to the ?ux in the magnetic circuit, and consequently “in cer tain relay applications, such as, a track circuit wherein it is desirable to maintain 'a constant 45 armature retaining force when the track section is unoccupied, it is desirable to maintain the flux in the magnetic circuit constant regardless of changes in intererail leakage current. A con stant ?ux Value can, of course, be maintained by an auxiliary means maintaining a constant value 50 of energization of the relay coils or the mag netomotive force of the relay but the present device does not act on the energizing circuit but 55 60 65 70 75 flux ?owing therethrough from one pole Ipiece . to the other, .and of course, the armature 3] also tends to ‘rotate to a position ‘wherein the :reluc tance to the flow of such flux .ltherethrough is a minimum or, that is, to place more of the sur 25 face of its pole faces in register with the surface " ’ Referring to Fig. vll which is a ‘view looking at 30 the lower end of the present relay with the ‘ar mature I’! removed, the rotatable armature 31 is shown as rotated to its extreme ‘position .in a rcounter-clockwi'se direction against ‘the biasing force of a spiral coil spring :38, which spring is 35 attached at its inner end to the top plate ‘I I by a ‘stud 39, and at its other end to :a sector 40 ‘by a pin will. The sector '40 "is also attached to the shaft 33 at a point above the armature .31 and extends rearwardly for a purpose to be later de~ 40 scribed. ‘ If the spring '38 is arranged to exert a force ‘tending to rotate the shaft 133 in a clockwise di rection which force increases evenly in direct proportion to the counter-clockwise rotation of the .shaft 33, the various values of magnetomo tive force between the pole pieces 9 .and vIll will effect a force counteracting the opposing force vof ‘the spring 38 only at certain de?nite rotated positions of the shaft 33. For example, when the armature 31 is in the position shown, each ' decrement in the magnetomotive force produces a ‘proportional degree of clockwise rotation of the rather, it acts on the magnetic circuit in a man shaft 33. Inasmuch as the upper end of the ner to maintain a constant flux value in the mag- - shaft 33 is provided with right-hand threads, netic circuit by varying the reluctance thereof the shaft will now be moved upwardly within in inverse proportion to changes in the mag the stationary threaded bushing '34 due to this netomotive force which occur gradually, and yet clockwise rotation, thereby allowing the arma~ allow the ?ux to decrease sufficiently in response ture H to move closer 'to'the pole pieces 9 and 13 to abrupt changes in the magnetomotive force This upward movement of the armature I‘! as to release the armature. ‘permitted by the upward movement of ‘the shaft 60 Inasmuch as one factor determining the reluc 33 obviously decreases the air gap between the tance of the magnetic circuit is the air gap sep armature H and the pole pieces 9 and I0, thereby arating the armature from the pole faces, the decreasing the reluctance of the magnetic circuit present device is arranged to enforce a separa in direct proportion to the'degree of reduction tion of the armature H from the pole faces 9 and in energization of'the coils l3 and M as detected 65 it which is in inverse proportion to the magneto by the rotation of the armature 31. In this man motive force obtaining between these pole pieces ner, the flux in the armature l? and consequently 9 and Ill. The preferred apparatus for effecting the tractive force acting thereon is maintained such operation is shown in Figs. 2 to 5 inclu at a constant ‘value regardless of the decrease 70 sively, and comprises a vertical shaft 33 positioned in the magnetomotive force or the energization midway between the cores 1 and 8 with its lower of the relay coils I3 and I4. I end rounded and engaging the upper surface of The converse action of the armature 31 is of the armature I‘! and its upper end threaded into course obvious, or that is, the shaft 33 will be a bushing 34. The bushing 34 is shown as rotated counterclockwise in response to a grad 75 2,135,490 ual increase in magnetomotive force to thereby screw the shaft 33 downwardly within the bush ing 34. This downward motion of the shaft in creases the reluctance of the magnetic circuit by forcing the armature I'I farther from the pole pieces 9 and I0 thereby preventing an increase of flux. " The pitch of the threads on the upper end of the shaft 33 will, of course, depend on the char 10 ‘acteristics of the magnetic circuit and on the ' proportion of various other parts of the relay, but it is to be understood that these threads must be arranged to vary the air gap between the ar mature I ‘I and the pole pieces 9 and I0 in such 15 a proportion to a change in magnetomotive force that the flux in the armature I‘I remains at a constant value. ~ ' a It was previously mentioned that the armature '3'! is to respond only to changes which occur 20 gradually in the magnetomotive force or the energization of coils I3 and I4, and the air gap should'not be varied in response to an abrupt de crease in relay energization. This is because the purpose of regulating the air gap is to allow the 25 armature to at all times drop away with equal certainty when the energization is quickly re duced, and if the air gap were varied in response to this quick reduction before the ~armature dropped away, the bene?t of the previous air gap 30 regulation would be lost. Consequently, the armature 31 is provided with two flux retarding washers or slugs 43 of a non magnetic current-conducting material, such as copper, brass or aluminum, and these slugs 43 35 completely surround'the armature 31 at posi tions‘ between the shaft 33 and the respective enlarged ends or pole faces. An effective amount of current is then induced in these Washers 43 when the ?ux in the armature 37 tends to change 40 quickly, which current acts to retard such change in?ux in a manner which is well recognized in the relay art. These slugs 43 will then act to re tard a rapid decrease in flux in the armature 3'! in response to a rapidly reduced relay energiza tion, thereby preventing an effective rotation of the armature 37 until the armature IT has been released by the reduction of the ?ux permitted by the inaction of they armature 37. However, ‘gradual changes in the relay energization or the magnetomotive force will produce such a gradual flux change through the armature 3'! that the flux retarding slugs 43 are practically ineffective, and the rotation of the armature 31. will follow very closely such gradual changes in magnetomo tive force. It is to be understood, however, that although the armature Il drops away before the armature 31 can respond to a, rapidly reduced ‘value of magnetomotive force, the armature 31 will sub60 sequently respond to this reduced value by ro tating to a position moving the shaft 33 down wardly. However, when the armature I1 is again attracted by a quickly increased value of magnetomotive force, the armature 3'! will not 05 immediately rotate back to again raise the shaft 33, and during the operation of the armature 3'! an air ‘gap will be momentarily provided which isn'ot proportional to the newly increased mag netomotive force. ' In some applications such operation of the armature 3'! while the‘ armature I1 is released, may be objectionable, and consequently the pres ent relay is provided with an upwardly extend ing spring arm 44 suitably attached to a rear wardly extending bracket 45 ?xed to the arma 3 ture I1 by screws 46 as shown in Fig. 3. The upper end of the spring arm 44 is positioned slightly to the rear of and out of engagement with the edges of the previously mentioned sector 40 when the armature I1 is attracted, but when the armature I‘! is released, the spring arm 44 is operated forwardly to engage the edge of the sector 40 and thereby prevent further movement of the shaft 33 while the armature I1 is in its released position. 10 Inasmuch as it has been considered that the rotation of the shaft 33 will not be more than about one-fourth of a revolution, the sector 43 may have a quarter circular outer edge concen tric with the shaft 33 as shown in Fig. 4, and the 15 right-hand edge may form a stop for the biased direction of rotation by engaging the down wardly extending head of the spring holding stud 39. The outer edge of the sector 40 may be roughened or serrated to provide a better fric~ 20 tional contact with the spring arm 44. The present device, of course, necessitates that the normal or average energization of the coils I3 and I4 be adjusted to a value which reliably 25 attracts the armature I ‘I from its deenergized position, and low enough to permit reasonably gradual variations either above or below this normal value to fall within the range of opera tion of the armature 31 in order to maintain a 30 constant ?ux in the armature El’. This constant armature ?ux must also be of a value which per mits‘ the most reliable armature release in re sponse to the degree of abrupt reduction in the energization of coils I 3 and I4 which is effected 35 in the particular circuit application. However, it is found in certain applications, such as railway track circuits, that even though the normal or average energization of the relay coils is a correct value, the abrupt reductions in 40 energization may be of considerably different magnitudes in different track circuits, due per haps to the different weights of trains shunting the track circuits, and the like. It then becomes desirable that this constant flux value in the 45 armature I ‘I be adjusted to a value providing prop er armature release in response to the degree of the abrupt energy reduction resulting from the particulartrain shunts, providing such ad justment does not affect the degree of energiza 50 tion required to pick up the armature. A rather simple means has consequently been provided for manually adjusting the normal or average air gap between the pole pieces 9 and I0 and the armature I ‘I when attracted, to there 55 by select a normal ?ux value in the armature I‘? which provides the maximum reliability of re~ sponse to the particular abrupt reduction of re lay energization effected in each application. ' This means is shown in Fig. 5 as comprising a 60 pointer arm 48 extending forwardly from the ?ange of the bushing 34 and having a pointer at its front end cooperating with arcuate gradu ations suitably marked on the top plate I I. The arm 48 may be rotated in either direction from 65 its illustrated position thus rotating the bushing 34 relatively to the shaft 33 to either move the shaft 33 upwardly or downwardly to accordingly vary the air gap between the armature I1 and the pole pieces 9 and I0, and consequently vary the normal value of flux in the’ armature IT. The adjusted position of the arm 48 may be re tained by a screw 49 threaded into the top plate II and extending through a circular slot in the outer end of the arm 48. 75 2,135,490 In Fig. 6‘ of the drawings, the same relay as shown in Fig. 2 is illustrated as having windings 59 on the rotating armature 31 in addition to the enters the track section to shunt the rails T, the energization of the relay coils l3 and I4 is quickly decreased, and inasmuch as the compensating ar non-magnetic current-conducting washers 43, mature 31 is retarded by‘ the washers 43 (not , which washers in this case, are made shorter to provide space for the coils 59. The two Iwindings shown in Fig. l) the flux decreases in the arma ture wVI‘! beyond a point where the retaining force 5B are shown as connected in series by a ‘wire 5| is overcome by the gravitational biasing force and and in multiple with the main windings I3 and thearmature I ‘I immediately drops away. The dropping of the armature I1 then engages the arm 44 with the sector 49 and prevents move ment of the compensating armature 31 as long as I4 by wires 52, and these windings 50 are arranged 10 to produce cumulative ?ux in the armature 31, which ?ux is to flow in the same direction as the ' ?ux produced in the armature 31 by energization of coils l3 and M. This arrangement in Fig. 6 substantially constitutes a shunt motor mecha nism for rotating the shaft 33, wherein the wind ings l3 and M supply the ?eld excitation coacting with the armature flux supplied by windings 59, and it is contemplated that additional torque tending to rotate the shaft 33 throughout its 90 20 degree rotation against the biasing spring 38 may thereby be provided. The washers 43 are intended to retard the ‘response of the armature 31 to rapid changes in energization of the relay in the same manner as in Fig. 2. The operation of ‘the previously described form of the present relay may be more clearly set forth by referring to Fig. l, in which a very diagram matic representation of the preferred form of the present invention is shown connected across one end of two track rails T, the other rail ends being connected to a battery B in series with a manually adjustable resistor R to thereby normallyenergize the windings of the present relay by current from .the battery B flowing through the track rails T 35 in series. The parts of the present relay‘ which are diagramatically shown in Fig. l have been given the same reference characters as assigned to the represented parts of the speci?c construction already described, and obviously this track cir 40 cuit current flows through windings l3 and I4 to attract and hold the armature IT in its upper position, which current is adjusted by the varia ble resistor R to provide .a predetermined desired value of magnetomotive force which is su?icient to easily attract the armature I‘! under normal or average leakage current through the ballast sepa rating the rails T when not shunted by a train. The manually adjusting arm 48 (not shown in Fig. 1) is now also adjusted to allowa ?ux value ‘the armature I‘! in response to this adjusted .50 in value of magnetomotive force, which produces a tractive force reliably retaining the armature I‘! in its attracted position, but which permits the reduction in magnetomotive force effected by the 55 train shunt obtaining on the particular track sec tion to reduce this ?ux value considerably below the value at which the relay armature l ‘I is found to drop away. In other words, the means for manually adjusting the air gap normally sepa rating the armature I‘! from the pole pieces 9 and l 0 provides a simple and convenient means for ad justing the release value of the relay armature without affecting the pick-up value. When the inter-rail leakage current changes in 65 the track circuit of Fig. 1, due, for example, to weather changes, the changes in relay energiza tion resulting therefrom occur gradually and the armature 37 rotates in a corresponding direction accordingly, thereby increasing or decreasing the reluctance of the magnetic circuit in inverse pro 7.0 portion to the change in magnetomotive force pro duced by the change in energization to maintain a constant flux, and obviously a constant tractive force acting on the armature I‘! in the manner previously described. However, when the train the track rails T are shunted. .10 It may be men tioned that this means for preventing the opera tion of the compensating armature 31 while the armature I‘! is released may be omitted from the 15 present devices and yet retain the most desirable operating characteristics, but in order to prevent unnecessary operation of armature 31 as pre viously outlined, its incorporation is considered advantageous. 7 An air gap compensating means is thus pro vided which operates to maintain a constant force 120 retaining the armature IT in its attracted posi tion regardless of various gradual changes in the energization of the relay. This arrangement then ; - insures that the relay armature releases in re sponse to a rapid reduction of energization with the same certainty regardless of the degree of energization of the relay coils which had prevailed before the rapid energy reduction. 30 In the .modi?ed form of the present invention shown in Fig. 7 and Fig. 8, substantially the same main magnetic structure has been shown in order 7 to simplify the disclosure, but the mechanical con struction of the compensating means is entirely different although the principle of operation is substantially the same. The speci?c construction in Fig. 7 and Fig. 8 comprises a horizontal mag netic shaft 55 rotatably supported in front of the pole pieces 9 and ID by two brackets 56 ?xed to 40 the top plate I I by bolts 5'! and nuts 58, which brackets 56 carry threaded pins 59 having re duced ends entering holes in each end of the shaft'55, as shown in Fig. 8. The pins 59 being threaded into the brackets 56 may be adjusted longitudinally to permit free rotation of the shaft 55 but substantially no longitudinal movement, and lock nuts 60 threaded on the pins 59 may be employed to hold the pins 59 in, such adjusted positions. The ends of the magnetic shaft 55 carry mag 60 netic vanes 62 and B3 clamped on reduced di ameter ends thereof by nuts 64, and these vanes are spaced to magnetically coact with the outer vertical edges of the pole pieces 9 and I0 re 55 spectively through small separating air gaps. The armature i‘! in this embodiment is, consid erably shorter than the spacing of the vanes 62 and 63, both for the purpose of clearing these vanes and to minimize the magnetic effect be 60 tween the vanes and the armature. A cam mem ber 65 is suitably attached to the center of the shaft 55 which cam 55 engages an enlarged head of a screw 66 threaded into a forwardly extending arm 61 suitably attached to the armature l1, the 65 screw 66 being locked in position by a nut 68. A coil spring 69 is provided around the shaft 55 with a center loop engaging the lower edge of a forwardly extending arm 10 on the cam mem ber 65, and the extreme outer ends of the spring 70 69 extend over the top of the shaft 55 toward the pole pieces 9 and ID with upwardly bent ends entering holes (not shown) in the top plate 'I I. The shaft 55 is thus biased in a counter-clock wise direction of .rotation. which direction of ro 5 2,136,490 tation is limited by a screw ‘H threaded through the, top plate H and locked by a nut 12 so that its lower end may engage the cam arm 10 when operated to its extreme upper position. be clearly seen from Fig. 7, or that is, these vanes are magnetically attracted upwardly against the intermediate position of the shaft 55. act with the respective pole pieces 9 and I0 may force of the spring 69 to register more of their 10 vertical surfaces with the outer surfaces of their respective pole pieces as the energization of coils l3 and M is increased, thereby rotating the shaft 55 in a clockwise direction in accordance with the degree of energization of the relay. The cam 15 65 is arranged as shown in Fig. '7 so that this clockwise rotation engages portions on its periph ery with the head of the screw 66 which are of continuously increasing radii, thus forcing the armature I1 away from the pole pieces 9 and ID. The pro?le of the cam 65 is then arranged to at all times enforce an air gap between the arma ture I‘! and the pole pieces 9 and In which is in inverse proportion to the magnetomotive force prevailing between the pole pieces. In order to retard the operation of the vanes in response to an abrupt change in magnetomo tive force, two sleeves 13 are provided on the shaft 55 between the cam member 65 and the two vanes 62 and 63, which sleeves are of a non-mag - T netic current-conducting material. These sleeves 13 then act as a ?ux retarding choke means which opposes a rapid change in the value of flux ?owing from one vane to the other through the shaft 55,»but are comparatively ineffective to retard gradual ?ux changes. The construction of the relay to which the modi?ed compensating means shown in Fig. '7 and Fig. 8 has been applied has been considered to be the same as previously described, in con nection with the other embodiments, but some modi?cations are obviously necessary such as the U-shaped armature-supporting bracket l8 (not shown in Fig. 8) , which in this case must be made wider in order to clear the vanes 62 and 63, and also the inner vertical edges of the pole pieces 9 and Ill are preferably plain in Fig. 7 and Fig. 8 instead of concave as shown in Fig. 4. Suitable contactsare of course to be operated by the armature l1 and such contacts are usual ly sufficiently ?exed when engaging the asso ciated upper ?xed contacts so that the varia tionsl‘in position of the armature l1 as caused ‘ by the compensating means will not affect the , resistance of the electrical circuit therethrough. The edge of the cam 65 which contacts with the head of the screw 66 has been rounded as shown tore-duce the frictional resistance to the rotation thereof to a minimum. 6,0 The operation of the modi?ed form of the present invention illustrated in Fig. '7 and Fig. 8 when applied to the railway track circuit of Fig. 1 is substantially the same as the other forms, or that is, when the track circuit current is ad a 7,0.~ through the shaft 55, and to the other pole pieces through the other vane, which ?ux produces an upward attraction of the vanes 62 and 63 which is equally opposed by the spring 69 only at an The manner in which the vanes 62 and 63 co 3.0 ing made because the normal degree of ener gization of coils l3 and I4 produces a flux ?owing from one pole piece, through the associated vane, The shaft 55 will now be rotated in either di rection by an upward or downward movement of the vanes‘ 62 and 63 in accordance with the gradual changes in the energization of coils l3 and M which may be caused by natural changes in the inter-rail leakage'current. The rotation of shaft 55 then varies the reluctance of the 16 magnetic circuit by the cam 65 in such a propor tion tov the changes in the energization of coils i3 and M that the flux in the armature I1 is maintained at the value selected by the screw 66. However when a train enters the track section, 20 the energization of coils l3 and I4 is quickly de creased, but due to the flux retarding sleeves 13, the flux in the shaft 55 does not immediately decrease proportionally, and consequently the reluctance of the magnetic circuit is not effec 25 tively changed by a rotation of the cam 65 before the armature l1 drops away. A means for pre venting a movement of the air gap regulating means while the armature I1 is dropped away has not been shown in this modified form, but it is 30 obvious that an arm operated by the armature IT, as shown in Fig. 3, could operate in a similar manner to engage an extension of the vanes 62 and 63, forexample, and thus prevent rotation of the shaft 55 while the armature I1 is in its 35 released position. In all the forms of the present disclosure, it has‘ been considered that the variations in the amount of flux passing through the compensat ing magnetic structures according to their ro tated positions do not materially affect the amount of flux passing through the armature ll, except due to the effected change in air gap, but it is obvious that the flux path through the armature 31 or the shaft 55 is in multiple with the path through the armature l7, and in some cases, it may be found that a change in position of the compensating means materially affects the armature l'l apart from the air gap variation. However, it is contemplated that in this case, the only result would be an over-compensation which could be recti?ed by a change in tension of the springs 38 or 69. A simple and compact relay has thus been pro vided which is particularly adaptable to nor mally energized circuits in which it is desirable to detect,‘ with great certainty, an abrupt re duction in the energization thereof. Many of such'norrnally energized circuits are materially affected by changes in natural conditions, such as gradual variations in the electromotive force of the source of energy, and changes in the inter rail leakage current in track circuits caused by equal certainty regardless of the natural condi tions which had prevailed previous to such abrupt tracted position may then be adjusted by the reduction. screw 66, under conditions providing‘ a normal or eration is accomplished is particularly reliable and advantageous because the reliability of the energizing circuit is in no way impaired by the average inter-rail leakage current, to produce a 50 55 60 varying weather conditions, and the present relay justed by the variable resistor R to a value, which by flowing through the windings l3 and I4 pro duce a ?ux which reliably attractsthe armature I‘! from its released position, the air gap between the pole pieces and the armature when in its at , flux value which affords a. reliable armature re 40 provides a means for detecting an abrupt reduc 65 tion in the energization of such a circuit with The manner in which the above op lease in response to a train shunt. The shaft 55 is of courseassuming an intermediate posi use of automatically variable resistors or the like, but rather a simple and positive means has been tion when the adjustment of the screw 66 is be employed to regulate the reluctance of the relay’s 7.5 2,135,490 6 magnetic circuit, thus preventing continued op eration from altering the electrical characteris tics of ‘the energizing circuit in any manner. The above rather speci?c description of the embodiments of the present invention is given solely by the way of example, and is'not intended, in ‘any manner whatsoever, in a limiting sense. It is also to be understood that ‘various modi ?cations, adaptationsand alterations may be ap 10 plied‘to meet the requirements of practice, with out in any manner departing from the spirit or scope of the present ‘invention, except as limited by the appended claims. ‘ Having thus described my invention, what I claim is: ‘l. A relay having in combination, a 'U-shaped magnetic structure, windings on the magnetic structure, amain armature attracted to a posi tion magnetically joining the ends of the U shaped magnetic structure When current above 20 operation of said means vbeing delayed in re sponse to changes in current in theelectromagnet which occur abruptly. 5. In a relay, an electromagnet having spaced extending pole pieces, a contact-operatingarma Cl ture positioned to magnetically-connect the pole pieces and ‘to vary the reluctance of the magnetic circuit of the electromagnet in accordance With its proximity to the pole pieces, a rotatable ar mature positioned between the pole pieces and 10 rotatable against a biasing spring to various po sitions in accordance with the magnetomotive force existing between/the'pole pieces, and means enforcing a separation of the contact operating armature from the pole piecesin accordance with the position of the rotatable armature whereby the magnetic flux in the contact operating arma ture is maintained a‘ constant value regardless of changes in the magnetomotive force of the, electromagnet. ' ' a predetermined value ‘?ows in the windings, a V 6. In a relay having electromagnetic structure threaded shaft interposed between the armature including windings about spaced magnetic cores, and the magnetic structure whereby the proxim the cores being magnetically joined at their upper ity of ‘the armature to the ends of the magnetic 25 structure may be determined in accordance with the rotated position of the threaded shaft, a magnetic member carried by the threaded shaft and coacting with the ends of the U-shaped magnetic structure whereby to rotate the shaft, ends and having enlarged pole pieces at their; lower ends attached beneath a non-magnetic top 25 plate; an armature operable toward and away from‘thellower surface of the pole pieces, a verti cal shaft between the pole pieces and having a lower end engaging the armature with an upper , end threaded into a holding member manually 30 rotatable within the top plate, amagnetic mem ber attached to the shaft and coacting'with'the 2; In a relay of the class wherein an armature vertical edges of the pole pieces in a manner to is moved toward an electromagnet in response magnetically effect rotation of the shaft in'one to a degree of energization of the electromagnet direction, a spiral spring acting‘v in opposition to 35 which is ,above ajpredetermined value and said the magnetic rotation of the shaft, a horizontal armature is moved away from the electromagnet sectcr‘attached to theshaft, and an arm operated by a biasing means when the degree of energiza by the armature toward the edge of the sector tion of the electromagnet falls "below said pre-. when the armature is operated away from the ‘ V determined value, the combination of, regulating pole pieces. means variably limiting the distance of move 7. In a relay having electromagnetic structure ment of the armature toward the electromagnet including windings about spaced magnetic cores, ' inaccordance with the degree-of energization of the cores being magnetically joined attheir upper ends and having enlarged pole pieces at their the electromagnet, and means retarding the re sponse of .the regulating means to abrupt changes lower ends attached beneath anon-magnetic top 45 in the degree of energization of the electro plate; an armature operable toward and away magnet. from the lower surface of. the ‘pole pieces, a verti ‘3. In a relay of the class wherein an arma cal shaft between the pole pieces and having a ture is held'toward an electromagnet in response lower end engaging the armature with an upper to a degree of energizationof the electromagnet end threaded into a holding member manually 50' which is above a predetermined value and said rotatable within the top plate, a-magneticmem armature is moved away from the electromagnet ber attached to the shaft and, coacting with the by a biasing means when the degree of ener vertical edges of .thepole ‘pieces, a winding on'the gization of the electromagnet falls below .said magnetic member arranged when energized to predetermined ‘value, the combination of regu magnetically effect rotation .of the shaft in one lating means variably ‘limiting the movement of direction, aspiral spring acting in opposition to, the armature toward ‘the electromagnet in, ac the ‘magnetic rotation of the shaft, a horizontal cordance with ‘the degree of energization of the sector attached tolthe shaft, and van arm operated electromagnet, means retarding ‘the response of by ‘the armature toward the edge vof. the sector the regulating means ‘to abrupt changes in the when the armature is operated ‘away from "the 60 degree of energization of the electromagnet, and pole pieces. ‘ " locking means ‘preventing operation of the regu 8. ‘In a relay having an electrom'agneti-cstruc- ' lating means while vthe armature .is operated time including windings about spaced magnetic away from the e'lectromagnet by ‘the biasing cores, the cores ‘being magnetically joined at their upper ends and having enlarged pole pieces 65 Ll. Ina relay, an electromagnet having two at their lower ends ‘attached beneath ‘a non extending pole pieces, an armature operable ‘to magnetic topplate; an armature operable'toward ward thepole pieces when current above a pre and away ‘from the' lower surface of "the pole determinedvalue ‘?ows in the .electromagnet and pieces, a magnetic'shaift rotatably carried ‘by the operable away from the pole pieces bylgravita top plate, rotatory biasing means acting on the 70 tional force when said current falls below said shaft, magnetic vanes ‘?xed to the ends of ‘the predetermined value, and means .coacting with shaft and coacting with the outer vertical sur the pole pieces ‘for variably separating the arma faces of the pole pieces whereby the shaft‘isro ture from the ,pole‘ pieces ‘in accordance with the tated .in opposition- to the rotatory ‘biasing means amount of current‘ in the electromagnets, the in accordance with the magnetomotive force ob-' and an arm .on the armature operable to pre vent rotation of theshaft while the armature is .1111 its unattracted position. ' 40 55 60 65 70 75 as’ means. i . 2,135,490 taining between the pole pieces, a cam operating to ‘enforce a separation of the armature from the pole pieces in accordance with the rotated position of the shaft, and a non-magnetic cur rent-conducting sleeve on the shaft whereby to retard the rotation of the shaft in response to an abrupt change in the magnetomotive force be-v tween the pole pieces. 9. In a relay wherein an electromagnet is nor 10 mally energized to attract an armature toward pole pieces of the electromagnet, the combination of a magnetic shaft rotatably held in a de?nite relation to the pole pieces, magnetic vanes on the ends of the shaft coacting with the pole pieces 15 in a manner to rotate the shaft, biasing means opposing such rotation of the shaft whereby the shaft is rotated to various positions depending on the strength of the magnetomotive force between the pole pieces, means retarding the rotation of‘ 20 the shaft in response to an abrupt change in the strength of said magnetomotive force, and cam means on the shaft operating on the armature to thereby regulate the separation of the arma ' ture from the pole pieces in inverse proportion to 25 gradual changes in the strength of said magneto motive force. ' 1 ed position when the track circuit‘ is unshunted, a compensating armature in the relay movable to various positions in accordance with the degree of energization of. the relay, means operated by the compensating armature to move the con tact-operating armature in a manner to maintain a constant flux‘ in the contact-operating arma ture regardless of gradual changes in the normal energization of the relay, and means retarding the response of the compensating armature to an 10 abrupt decrease in energization of the relay, whereby to permit the contact-operating arma ture to drop away in response to a shunt on the track circuit before the compensating armature eifectively moves in response to such shunt. 15 14. In a track circuit, a track relay, a ?rst ar mature in the track relay attracted or released in accordance with the unshunted or shunted condition of the track circuit, and a second ar mature in the track relay regulating the at 20 tracted position of the ?rst armature in accord ance with gradual changes in the degree of en ergization of the track relay when unshunted, whereby to permit the release of the ?rst arma ture in response to a shunt on the track circuit 25 with equal certainty regardless of the prevailing V 10. In a relay wherein an electromagnet is nor ballast condition in the track circuit. ~ mally energized to attract an armature toward 15. In a track relay, a ?rst armature attracted or released in accordance with abrupt changes in the degree of energization of the relay, and a 30 second armature regulating the attracted posi tion of the ?rst armature to maintain a constant ?ux density in the ?rst armature regardless of pole pieces of the electromagnet, the combination 30 of a magnetic shaft rotatably held in a de?nite relation to the pole pieces, magnetic vanes on the ends of the shaft coacting with the pole pieces in a manner to rotate the shaft, biasing means 0p posing such rotation of the shaft whereby» the shaft is rotated to various positions depending on the strength of the magnetomotive force between the pole pieces, means retarding the rotation of gradual changes in the degree of energization of the relay. 35 16. In a track relay, an electro-magnet hav ing extending pole pieces, an armature operable the shaft in response to an‘ abrupt change in the toward said pole pieces when current above a strength of. said magnetomotive force, cam means predetermined value flows in the electro-magnet and operable away from the pole pieces by grav 40 40 on the shaftoperating on the armature to there by‘ regulate the separation of the armature from the pole pieces in inverse proportion to gradual changes in‘ the strength of said magnetomotive force, and means for manually adjusting the 45 separation of the armature from the pole pieces which permits subsequent regulation thereof by the cam means. I ‘11. In a relay, two vertical magnetic cores joined at one end and having enlarged pole pieces 50 at the other ends, a non-magnetic member-hold ing the cores, windings on the cores, an arma ture operable toward or away from the pole pieces in accordance with the degree of energization of the windings, a manually rotatable member 55 in the core holding member, a shaft threaded into the manually rotatable member and engag ing the armature when operated toward the pole pieces, and means for automatically rotating the shaft in accordance with gradual changes in the 60 degree of. energization of the windings. 12. A relay having in combination, an electro magnet having an incomplete magnetic core, a contact operating armature operable to a position completing the core of the electromagnet, and 65 magnetic means automatically providing a length of air gap between the armature and the core of the electromagnet which is in inverse propor tion to the degree of energization of the electro magnet, wherebyto maintain a constant value 70 of magnetic ?ux in the armature regardless of gradual changes in the degree of energization of the electromagnet. 13. In a normally energized track circuit, a relay energized by the track circuit current to 75 hold a contact-operating armature in an attract itational force when said current falls to‘ a pre determined lower value, slow acting adjusting means for variably separating the armature from the pole pieces when in its attracted position in accordance with gradual changes in the potential 45 across said electro-magnet, and means for look ing said adjusting means upon dropping of said armature. I 1'7. In a relay, a magnetic core structure ter minating in two pole pieces, a winding mounted 50 on the core, an armature biased to a position away from the pole pieces and movable toward said pole pieces in response to magnetic flux created by current supplied to the winding, a magnetic shunt path including a magnetizable 55 member movable to different positions relative to said pole pieces for regulating the ?ux which passes through the armature in response to variations in the magnitude of the current sup plied to the winding, and means controlled in 60 part by said armature for governing the posi tion of said member. 18. In a relay, a magnetic core structure ter minating in two pole pieces, a winding mounted on said core, an armature mounted for move 65 ment relative to said pole pieces in response to magnetic ?ux created by current supplied to said winding, an auxiliary magnetizable member mounted for movement relative to said pole pieces in response to such magnetic ?ux for regulating 70 the ?ux through the armature in response to variations in the current strength supplied to the winding, a biasing device for governing the posi tion of said member when in?uenced by the ?ux, and means controlled by said armature operative 75 8' area-r90: when the armature is‘ released in. response. to. de'energizing the winding to‘ retain. said auxiliary member at the position. to which it was moved ?ux created by current. ?owing in said winding, by the magnetic. flux; magnetic an auxiliary pathmovable in shuntarmature with said main disposed armature‘ in and responding to variations in the. current in said winding, spring means for biasing said aux iliary armature with a force varying with its position toward a position for maximum reluc tance of said. shunt path, said auxiliary arma 110-. ture' assuming, different positions in its. magnetic shunt path dependent upon the strength of the . 19. In combination, a section of railway track‘, a source of. current connected across: the rails of: said‘ section, an electromagnet receiving’ current from. said rails and‘ having an armature ad justed for operation when the‘ magnetic ?ux‘ act ing thereon is‘ that‘ created by a predetermined value of current, amovable magnetizable mem ber operable to: different positions‘ relative to’ the core structure of the electromagnet for regu lating the flux which passes through said arma ture to reduce in the. armature the. ?ux created by currents greater than said predetermined value, and means controlled in part by the posi~ tion. of said armature for governing. the position of said member. 201' for movement away from said pole pieces and attracted: toward said pole pieces: by magnetic? current in said winding, and means actuated by’ movement of said main armature to its rc tracted position for retaining said auxiliary ar 195? mature in its then existing position. 23., A relay of the direct current tractive type for use’ on railroads comprising, a core structure the magnetic flux through the armature when current above a predetermined value is sup-plied to the Winding, and a short-circuited winding mounted on the shunt path for delaying the dying away and the building up of flux through said shunt path. 21. In combination, a section of railway track, and a winding for attracting a biased movable armature. to open. and close contacts, a magnetic 26; movable member disposed in a magnetic ?ux path in shunt with said armature, spring means for biasing said member to a position for the maximum reluctance of said shunt path, said member being moved inv opposition to said spring means by variations in the current flowing insaid winding; to different positions dependent upon the: magnitude- of such.‘ current, means asso ciated with» said movable member for delaying a change in its position in response to a change 301~ in the current in. said winding, and means. re sponding to the movement of said armature toits retracted. position for retaining said member in the position existing at the time said armature a source of current connected across the rails assumes its retracted position. ‘20. In a relay; a: magnetic, core structure ter minating in two- pole pieces, a winding mounted on said core; an armature mounted for move ment. relative to said pole pieces in response to: magnetid ?ux created by current supplied to 2a vsaid winding, a magnetic shunt path including a magnetizable member mounted for magnetic relationship with said pole pieces for regulating , 24-. In av relay of the type described, a magnetic of said section, a track relay receiving current from said rails and adjusted for release of its core structure‘ terminating in two spaced pole ' armature at a predetermined value of current, pieces, a winding on said core structure, a main a movable magnetizab-le member mounted» for movable armature attracted toward said pole pieces by- the magnetic flux in said core structure 44-) movement relative to the pole pieces of the relay by flux ?owing in multiple with said armature, produced by current flowing in said winding, and means to» associate movement of the member with movement oi’- the armature’ whereby a-v means including a.- biased movable auxiliary ar mature disposed in a magnetic flux path in shunt gradual change in the ballast resistance of the. section automatically changes the setting of the passing through said main armature depending, member but a sudden decrease in the energizing current to release the: armature causes the mem ber to be retained in its former setting. 22. A relay of the» direct current. tractive type for use with track circuits on railroads com,-» prising, a magnetic core structure forming two. spaced polle- pieces, a winding on said core struc ture, a main contact operating armature biased with said main armature for varyingthe ?ux upon the magnitude of current in said winding, a short-circuited winding associated with said shunt path for retarding a change of flux there in, and means» actuated by movement of said main'armature to its retracted position for hold-. 5(11 ing said auxiliary armature inv its then. existing position. ~ > EDWIN O. BLODGETT.