US2024217A - Circuit breaker - Google Patents

Description

Dec. 17, 1935. s. s. GRADY 2,024,217

CIRCUIT BREAKER Original Filed May 6, 1932 2 Sheets-Sheet 1 VIL /s I. d, gli

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STEPHEN 5. GRADY 3 ATTORNEY.

@l 76 z5 1 f M73 5 54 76 @573 352455 Dec. l2, 1935. s. s. GRADY CIRCUIT BREAKER Original Filed May 6, 1932 2 Sheets-Sheet 2 .INI/EN TOR. STEPHEN 5. 5W/:DY

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Patented Dec. l*12935 t UNITEDYSTATES PATENT OFFICE CIRCUIT BREAKER Stephen S. Grady, Magnolia., N. C., assign'or to usoid Electric Co., Inc., a corporation o! New ork Application May 6, 1932, Serial No. 609,597 Renewed February 28, 1935 18 Claims. (Cl. 20o- 88) This invention relates to electric current conwith the cover removed on a smaller scale than trolling or electric current change detecting that illustrated in Fig. 1; devices in general and more` especially to electric Fig. 4 is a section on the line 4-4 of Fig. 1; circuit breakers. Fig. 5 is a section on the line 5-5 of Fig. 1;

5 Among the objects of the present invention, itis Fig. 6 is a section on the line I-f-Ii of Fig. 1; 5 aimed to provide an improved electric current Fig. 'I is a perspective of the actuating elements controlling or change detecting device by means of the circuit breaker and of the main` elements of which an indicator or actuatorl may be acted constituting the electric Current Change Sensing upon to indicate either a gradual abnormal indevice; and

crease in current or light overload or a sudden Fg- 8 is a perspective 0f a detail 0f the circuit 10 abnormal heavy increase in current or heavy breaker appurtenant t0 the tripping deVCe 0f the overload. circuit breaker.

Speciilcally it is an object of the present in- In the embodiment illustrated, there is provention to provide an electric current controlling vided a casing I composed of some suitable inor change detecting device consisting essentially sulating material such as bakelite or the like. l5 in a magnet that will not only detect a persistent This casing in the present instance consists of light overload or a persistent light increase in end walls 2 and 3, side walls 4 and 5 and a bottom current but also detect a sudden heavy overload wall 6. or sudden heavy increase in current. The end wall2, see particularly Fig. 1, prefer- It is still another object of the present invenably is recessed at 1 below its upper edge, which 20 tion to provide an improved magnet consisting of recess will register with the adjoining recess 1 a core and a bimetal coil by means of which an of an adjacent casing I to permit the insertion electric current detecting indicator may be acted of an insulated sheet or plate 8 to facilitate inupon not only when a persistent light overloador sulating the terminals in the end walls 2 now to :z5 a persistent light increase in current occurs but be described. l 25 also when a sudden heavy, overload or sudden The bottom wall 6 ofthe casing I, see particuheavy increase in current occurs. larly Fig. 1, is provided with a recess 9 adja- It is still another object of the present invencent to the end wall 2. This recess 9 is of contion to provide an improved combined magnet siderable advantage when a plurality ci these `so and thermostat which will thermostaticaliy effect casings are grouped adjacent to one another and an interruption in an electric current when a as illustrated in Fig. l, and a common bus bar I0 light overload or light increase in current occurs is connected to the alined terminals of the adjaand will magnetically effect an interruption in the cent casings. current when a sudden heavy overload or sudden The drawings illustrate a circuit breaker a1- increase in current occurs. though it is obvious that the main elements of 'I'he present invention also aims to provide a this device may be effeetively used in any eleccircuit breaking device having a casing particutrical current change detecting device or current larly adapted for use with a group of circuit Controlling device. 1 breakers, similarly encased both to conserve When these elements are used in a circuit 40 space and to facilitate insulation one from the breaker and casing I aforesaid iS used, then Pref- 40 other without any loss of wall space or the like. erably a Conductor plete II iS Connected togthe These and other features, capabilities and adlower face of the casing in the recess 9, which vantages of the invention will appear from the conductor II has a U-shaped end POItOn I2, the subjoined detail description of one speciiic emupper face of the upper flange of which is disbodiment thereof illustrated in the accompanying posed iiush with the lower face I4 of the vinner 45 drawings, in which face of the wall I adjacent to the side wall 2 Figure 1 is a longitudinal section of a circuit and such flange I3 completely encloses the disbreaker in circuit making position made accordcharge end of the opening I5 formed in the boting to the present invention and illustrating the tom wail 6 communicating with the recess 9. improved electric current change detecting ele- Forwardly of the opening I5, the bottom wall 6 60 l ments; is preferably chambered as at I6, which cham- Fig. 2 is a fragmental longitudinal section bered portion I6 is further depressed at its rear showing the circuit breaker in circuit breaking end as at I 'I. In circuit making position, the Y position; upper face of the conductor II constituting one Fig. 3 is a plan view of the circuit breaker terminal of this device contacts with the shoe It l5 at the rear end of the spring I9, which spring is connected to `the plate 26, the extensionsy 2I and 22 oi which, see Fig. 8, are preferably secured in place to the bottom wall 6 forwardly of the recess I1 by the screws 23 and 24.

'I'his shoe is further connected by the flexible conductor 25 with the bimetal coil 26. This bimetal coil in the present instance is composed of adjacent layers of invar steel and brass and rolled up into a coil to form for the purpose of one part of this invention, the coil of a magnet, the inner end of which coil 26 has secured thereto the soft iron core 21. This core 21 and inner end of the coil 26 is preferably connected to the vlateral extension 28 of the plate 29, which see Fig. 3, has its end disposed in the recess 36 where itI is preferably anchored in place by the screw 3 The end portion 32 of the plate 29 is connected to the main conductor 33 by the terminal screw 34. 'I'he extension 23 of the conductor 29 preferably has its free end diminished as indicated at 35 to ride in the recess 36 formed in the side wall 5 of. the casing.

'I'he core 21 of the magnet, see particularly Fig. 3, has its ends extending beyond the coil 26. The free ends of the core 21 are so exposed to facilitate cooperation with the wings 31 and 33 of the bracket 39, such wings 31 and 33 extending upwardly to Yeither side of the coil 26 and the bracket 39 itself being pivoted by means of the pivot extensions 46 and 4I being journaled in the openings formed in the upwardly extending flanges 42 and 43 of the plate 44 which is secured to the bottom wall 6 by means of the screw 45.

The rear end of the plate 44 is preferably provided with a forwardly extending projection 46 in its raised position due to the spring 41. 0n the other hand when rocked downwardly by the rearward movement of the wings 31 and 38, the circuit breaker will be released to snap into circuit breaking position.

Before proceeding to a detailed description of the circuit breaking device, it may be of advantage here to point out that when a light overload or light increase in current, and preferably a persistent or sustained light overload occurs, the current passing from the terminal II to the terminal29, the coil 26 will heat up and thereby thermostatically actuate the bracket 39 by causing the extensions 49 and 56 of the outer end of the coil 26, see particularly Fig. 7 to rise into engagement with the wings 31 and 33 to move them rearwardly and thereby to depress the.

On the other hand when a sudden heavy overload or sudden increase in current occurs, the magnetic force created by the magnet and particularly the magnetic attraction set up in the soft iron core 21 will attract the wings 31 and 33 of the bracket 39 again to depress the arm 43. It is of course to be understood that the bracket 39 is composed of a current conducting metal, preferably a conductive metal.

In the present instance, the terminal plate Il, see particularly Fig. 1, is connected to the main conductor by the terminal screw 32 to which on the other hand the bus bar I6 may be connected instead of the main conductor when a group of these devices are disposed adjacent to one an other. 5

The circuit breaking device consists essentially of an interposer composed of a plate composed of some suitable insulating material such for instance as bakelite or the like. The rear end 54 of the plate 53 is flared as shown, the for- 10 ward end of which is provided with two lateral arms 55 and 56, at the extreme forward ends of which are provided the projections 61 and 63 to receive the springs 5,9 and 66 which are preferably disposed in arcuate recesses formed 15 in the casing I, see particularly Fig. 6, with their forward ends abutting against the rear faces of the bosses 6I and 62 respectively.

'Ihe plate 53 in width preferably extends across the entire expanse of the interior of the casing 20 from one side wall 4 to the other side wall 6 and is mounted to slide on the face I4 and the shoulders 63 and 64 forwardly of the face I4.

It would also appear from the foregoing that when the interposer 53 is in circuit breaking posig5 tion, that illustrated in Fig. 2, it will completely cover the upper face of the flange I3 so that in circuit breaking position the current cannot possibly arc around the interposer from the shoe I3 to the flange I3. o

The interposer 53 is provided with downwardly extending projections 65 and 66 preferably formed on a metal plate 61 secured to the interposer plate 53. These projections 65 and 66 are adapted to cooperate with the forward face or 35 shoulder 63 of the crosspiece 69 formed on the bracket 39 and the forward end or shoulder formed by the finger 16 extending down from the bracket 39, the projection 66 engaging the finger 16 and the projection 65 engaging the 40 shoulder 63 in circuit making position, that illustrated in Fig. 1.

On the other hand when the arm 43 of the bracket 39 is depressed downwardly against the tension of the spring 41, due to the rearward 45 movement of the wings 31 and 33 as aforesaid when an abnormal or changed current condition arises, the finger 16 and shoulder 66 will move out of engagement with the projections 66 and 65 respectively ofthe interposer 53 and permit 50 the springs 59 and 66 to snap the interposer forwardly into circuit breaking position where, see Fig. 2, the plate 53 will slide under the shoe I6 and urge it upwardly out of contact with the flange I3 against the tension of the spring I9.

For resetting the interposer 53 into circuit making position, the handle 1I is provided which is preferably composed of bakelite or the like or other suitable insulating material and in the present instance has an extension or finger en- 60 gaging portion 12, an enlarged arcuate portion l 13 to the inner end of which arcuate portion, there is secured a metal bracket 14 having trunnions 15 and16 formed on lateral extensions therer of journaled in the upwardly extending ends of J the lateral extensions 11 and 13 of the plate ,19 from which the extensions 2I and 22 extend.

The plate 19 preferably at the lower ends of the wings 11 and 13 is provided with the projec- 7o tions 36 and 8| to rest in the recesses 32 and 33 of the casing I.

This handle 1I is preferably provided with a coil spring 84 for normally urging the extension 12 in a forward direction, that illustrated in 75 Pig. 2, the spring 94 being tensed between the plate 14 and the abutment 99.

To the plate 14, there is pivotally connected the levex` 99, which see Figs. 5 and 8, has a projection 91 adapted to ride under a portion oi' the spring I9. The lever 99 is provided with a spring I9 normally to urge the lever 88 so that its projection 91 will tend to move under the adjacent portion of the spring I9. The spring I9, see particularly Fig. 8, is provided with an opening 99 to permit the iever 99 to extend down through it.

The upper face of the projection r91 forms an oblique angle with the shortest radius to it from the center of the arm I9.

This oblique angular relation of the upper face of the projection 91 to the axis of the arm 99 is of importance in the action of this device and will be hereinafter described.

After the interposer B9 has been moved into circuit breaking position, that illustrated in Fig. 2, it will only be necessary to engage the extension 12 of the lever 1| and move it rearwardly into the position, illustrated in Fig, l when its lever 99, extending as it does through the spring I9 and into engagement with the shoulder 90 of the plate 91, will thereby move forwardly with u it the interposer plate 59 until its projections II and I9 pass the shoulders 99 and 10 of the bracket 99 when the interposer plate 59 will again be locked in circuit breaking position by the bracket 99. After the lever 1| has so moved the interposer plate 59 into circuit making position, it will then be necessary for its lever 99 to be moved out of the path of movement of the shoulder in order to permit the interposer plate 59 subsequently to be urged into circuit breaking position without interference with the lever 96 and in addition thereto it will be desirable to anchor the lever 1| against movement in such circuit making position.

In order that the lever 99 may clear the shoulder 99 after moving the interposer 53 into circuit making position, it will be found that the following action takes place.

In circuit breaking position, the projection 91 due to the tension of the spring 99 will ride under the spring I9 whereupon during the forward movement of the interposer 59, the frictional contact of the arm 99 with the shoulder 90 will so .anchor the lever 99 that it will not move about its pivot but positively return the interposer 59. However, after the interposer has been returned and anchored into position by its cooperation with the bracket 99 and the release of the lever 1| takes place so that the frlctional contact of the arm 99 with the shoulder 90 will have been broken, then the downward urge of the spring I9 on the upper face of the projection 91 will act to cam the lever 99 out of engagement with the spring I9 against the tension of the spring 99.

At this time, however, it will be desirable as aforesaid to anchor-the lever against movement in circuit making position. For this purpose. there is provided the lever 9| pivotally connected to the wing 11 of the plate 19. This lever has a lateral extension 92 and a downwardly extending shoulder forming portion 99. The shoulder forming portion 99 will engage the lateral extension 94 of the plate 14 when in circuit making position and thereby anchor the lever 1| in circuit making position. The lateral extension 92, see particularly Figs. 2 and 8, is disposed adjacent to the raised portion 95 of the spring I9 and consequently when the spring I9 is raised during the circuit breaking action, this extension 9| will engage the lateral extension 92 to raise the lever 9| against the tension of the spring 94 and thereby permit the spring I4 to cause the plate 14 to pivot about its axis with the upper extension 12 moving forwardly. The 5 the spring 94 serves not only to maintain the 10 rear arm of the lever 9| in engagement with the lateral extension 94 of the plate 14 but also to exercise an angular tension on the plate 14.

From the foregoing, it will thus appear that when the magnet consisting of the coil 29 and 15 core 21 is inserted in the conductors of an electric circuit, it may control a circuit breaker to protect the line of which the conductor or bus bar I0 forms a part with the conductor 99 as specifically illustrated in Fig. 1, or else these elements may form the main actuating elements of a current change sensing or current controlling device in which either when an abnormal current or a different current is passed through the system, either the core 21 will cooperate with an actuator, such as the bracket 99 or the thermostatic action of the coil 29 will cooperate to actuate an actuator such as the bracket 99 either to indicate such change or abnormal condition. or

else to initiate a change to overcome or bring 30 about a return to normal.

The casing I is preferably provided with a suitable cover of insulating material such as the cover 96 which is preferably connected to the casing by the screws 91 and 98 shown in section in IFig. 4 3 which pass through the openings 99 and |00 of the casing I, shown in Fig. 3.

The cover preferably has an opening |0| with arcuate flanges |02 to either side thereof, the ends |09 and |04 of which slot |0| are preferably 4 substantially radial to the axis of the lever 1|, the enlarged portion 13 conforming to the inner arc of the flanges |02 so as to substantially shut off access to the interior of the casing when the cover is closed and to prevent the discharge 4 of any electric arc flashes.

It is of course obvious that the bracket 99 will not return into position where it will lock 'the interposer 59 until the condition causing the overload has been removed and the overload relieved, even though the resetting handle 1| is operated to actuate the interposer into circuit making position and that the automatic return of the in terposer into circuit breaking position as soon as the handle is released due to this action of r the bracket 99 will in turn actuate the trip for d the handle to permit it to be rotated into circuit breaking position.

This action of the bracket 99 is of course due to the fact that during the overload the wing porc tions will be maintained in tilted position when the lower portion 49 will be maintained in depressed position where it cannot anchor the interposer in circuit making position.

To facilitate adjusting the position of the projections 49 and 50 at the end of the bimetal coil 29 either nearer or farther away from the core 21 due to the moldability of the copper plate 29 which is an integral part of the plate 29 if the diminished neck portion |01 betweenthe plate 7 portions 28 and 29 is engaged by a tool such as the device |05 having the jaw I 09, the plate 29 may be readily bent in one direction or the other either to move the projections 49 and 50 nearer to the wings 91 and 99 or farther away from the 7 same, according to the adjustment required.

1 It is obvious that various changes and modiilcations may be made to the details oi' construc- -tion without departing from the general spirit of the invention as set forth in the appended claims.

I claim:

1. An electric current change sensing device -f consisting of a magnetic device connected to the conductors of an electric circuit to form a part ot an electric circuit, said magnetic device com- -1 prising a, bimetallic coil, and a core connected to the inner engl of said coil, the outer end of the coil and said core forming the terminals of 'said magnetic device, and an Aactuator normally spaced from said core and forming a part oi a current controlling device operatively associated with said magnetic device to be actuated toward said core either by the thermostatic action oi said coil or the magnetic action of said core.

2. In an electric controlling device, the combination with an actuator, ot a magnetic device forming part of the electric circuit to be controlled comprising a bimetallic coil, and a core connected to the inner end of said coil, the outer end oi the coil and said core forming the terminals of said magnetic device, saidactuator being operatively associated with said magnetic device to be actuated toward said core either by the .thermcstatic action of said coil or the magnetic action of said core.

3. 4In an electric current controlling device, the combination with a pivotally mounted metallic actuator, of a magnetic device forming part oi 'the electric circuit to be controlled comprising a .bimetallic coil, and a core secured to the inner end of said coil, said coil having an abutment at its outer end, one arm of said actuator being disposed between said abutment and said core to be actuated either by said abutment during the thermostatic'action of said coil or said core during the magnetic action of said core.

' 4. In an electric current controlling device, the combination with a pivotally mounted metallic actuator, of a magnetic device forming part of the electric circuit to be controlled comprising a 1 abutment at its outer end and having a core at.

its inner end, said actuator being operatively disposed between said abutment and said core to be operated by either one or the other or both.

6. The combination with two terminals of a 'main circuit, of a circuit breaker connected to said terminals, said circuit breaker compris- 'ing a xed contact connected to one of said terminals, a magnetic device connected to the other of said terminals, a movable contact connected to said magnetic device, an interposer ior deecting said movable contact out oi' engagement with said fixed contact, said magnetic device comprising a. thermostatic coil having an abutment at its outer end and a coil'at its inner end, means for normally urging said interposer into circuit breaking position, and an anchoring device for anchoring said interposer vin circuit making p'osition,`said anchoring device beingl operatively associated with said abutment and core to be actuated to release said interposer either by'the magnetic action oi the core with a sudden heavy overload or by the movement of said abutment '5 during the thermostatlc action of said coil" with a persistent light overload.

7. The combination with two terminals of a main circuit, of a circuit breaker'connected to said terminals, said circuit breaker comprising a 10 iixed contact connected to one of said terminals, a magnetic device connected to the other of said terminals, a second contact connected tol said magnetic device, a spring for normally maintaining said second contact in engagement with said ,15

fixed contact, an interposer, means for actuating said interposer to deflect said second contact out of engagement with said ilxed contact to interrupt the circuit, and an anchoring device for anchoring said interposer in circuit making position, 20 said magnetic device having a thermostatic coil with an abutment at one end ther'of and a core at the other end thereof in operative association with' said anchoring device* to actuate the same upon a change in current in turn to release said '25 interposer.

8. .'I'he combination with two terminalsof a main circuit, of a circuit breaker connected to said terminals, said circuit breaker comprising Ya fixed contact connected to one of said terminals, 3o

an electromagnetic device connected to the other of said terminals, a Asecond contact connected to said electromagnetic device and normally engaging said xed contact, an interposer, means for actuating said interposer to deflect said second 35 contact out of engagement with said xedcontaot, and a pivotally mounted bracket having one arm normally anchoring said interposer in circuit making position, said electromagnetic device comprising a bimetalic coil having an abutment at 4, one end and a core at its inner end, the other arm of said bracket being disposed between said abutment and said core in position to be actuated by the magnetic action of said core during a heavy overload and`to be actuated by said abutment 45 during a persistent light overload-in turn to release said interposer.

' 9. 'The combination with two terminals oi`a4u main circuit, of a circuit breaker connected to said terminals, said circuit breaker comprising a 59 fixed contact connected to one of said terminals, an electromagnetic device having a movable coil connected to the other of said terminals, a'second contact connected to said electromagnetic device and normally engaging said fixed contact, an 55 interposer, means for actuating said interposer to deflect said second contact out of engagement with said fixed contact, an anchoring device actuatable both by the movement o f said coil and the magneticiniluence exercised by said coil when 60 energized for normally'anchoring said interposer in circuit making position, and a resetting -device operatively connected to said interposer to rese the same in circuit making position. r y

10. The combination with two terminals of v`a 65 main circuit, of a circuit breaker connected to said terminals, said circuit breaker comprisingca iixed contact connected to one of said terminals, an electromagnetic device connected to= the other of saidterminals, a second contact connected' to 70 'said electromagnetic device and normally engaging said fixed contact, an interposer, means i'r actuating said interposer to de'iiect said second contact out of engagement with said iixed coritact. an anchoring device controlledby said elee- 75 tromagnetic device for normally anchoring said interposer in circuit making position, and a resetting device comprising a pivotally mounted bracket, an arm pivotaily connected to said bracket, a spring for urging said arm into engagement with said interposer, and a cam on said arm for guiding said arm out of the path of movement of said interposer after having sent the same in circuit making position.

11. The combination with two terminals of a main circuit, of a circuit breaker connected to said terminals, said circuit breaker comprising a xed contact connected to one of said terminals, an electromagnetic device connected to the other of said terminals, a second contact connected to id electromagnetic device, a spring for normally maintaining said second contact in engagement with said xed contact, an interposer, spring means for urging said interposer into circuit breaking position, an anchoring device normally anchoring said interposer in circuit making position and adapted to be actuated by said electromagnetic device to release said interposer, and a resetting device comprising a pivotally mounted bracket, an arm pivotally connected to said bracket, a spring for urging said arm into engagement with said interposer in circuit breaking position preparatory to resetting action, and a cam on said arm cooperating with said spring to cam said arm out of the path of movement of said interposer after having reset said interposer in circuit making position.

12. The combination with two terminals of a main circuit, of a circuit breaker connected to said terminals, said circuit breaker comprising a iixed contact connected to one of said terminals, an electromagnetic device connected to the other of said terminals, a second contact connected to said electromagnetic device, means for normally maintaining said second contact in engagement with said fixed contact in circuit making position, an interposer, spring means for actuating said interposer to deflect said second contact out of engagement with said fixed contact, a bracket pivotally mounted and having two upwardly extending Wings, one to either side of said electromagnetic device, and a second arm normally anchoring said interposer in circuit making position, said electromagnetic device comprising a bimetallic coil with an abutment at one end and in front of said wings and a core at its inner end in back of said wings to facilitate actuation of said bracket either by said abutment or by said core.

13. The combination with two terminals of a main circuit, of a circuit breaker connected to said terminals, said circuit breaker comprising a xed contact connected to one of said terminals, an electromagnetic device having a movable coil connected to the other of said terminals, a second contact connected to said electromagnetic device and normally engaging said fixed contact in circuit making position, an interposer for deecting said second contact out of engagement with said fixed contact, an anchor for normally anchoring said interposer in circuit making position and actuatable by the movement of said coil and by the magnetic inuence of said coil when energized, a resetting device adapted to return said interposer into circuit making position, and means for anchoring said resetting device in circuit making position.

14. The combination with two terminals of a main circuit, of a circuit breaker connected to said terminals, said circuit breaker comprising a xed conta"L connected to one of said terminals,

an electromagnetic device connected to the other of said terminals, a second contact connected to said electromagnetic device and normally engaging said fixed contact in circuit making position, an interposer for deecting said second contact out of engagement with said xed contact, an anchor for normally anchoring said interposer in circuit making position and actuatably associated with said electromagnetic device, a resetting device adapted to return said interposer into circuit making positon, means for anchoring said resetting device in circuit making position, and means associated with said second contact to release the anchoring means for said resetting device in case of an overload.

15. In an electric current controlling device, the combination with a pivotally mounted metallic actuator, of a magnetic device forming part of the electric circuit to be controlled comprising a bimetallic coil having an abutment at its outer end, a core at its inner end, one arm of said actuator being disposed between said abutment and said core to be actuated either by the magnetic attraction of said core or by engagement with said abutment during the thermostatic action of said coll, and a metal bracket for supporting said core and bendable to facilitate adjusting the position of said abutment re1- .ative to saidbracket.

16. The combination with two terminals of a main circuit, of a circuit breaker connected to said terminals, said circuit breaker comprising a iixed contact connected to one of said terminals, a magnetic device connected to the other o1' said terminals, a movable contact connected to said magnetic device, an interposer for deflecting said movable contact out of engagement with said iixed contact, said magnetic device comprising a thermostatic coil having an abutment at its outer end and a core at its inner end, means for normally urging said interposer into circuit breaking position, and an anchoring device flor anchoring said interposer in circuit making position, said anchoring device being operatively associated with said abutment and core to be actuated to release said interposer either by the niagnetlc action of the core with a sudden heavy overload or by the movement of said coil with a persistent light overload, and said anchoring device being maintained in such released position either by the magnetic attraction of said core or by the thermostatically controlled position of said abutment until the overload is removed.

17. In an electric controlling device, the combination with an actuator, of a magnetic device forming part of the electric circuit to be controlled comprising a bimetallic coil, and a core connected to the inner end of said coil, the outer end of the coil and said core forming the terminals of said magnetic device, said actuator being operatively associated with said magnetic device to be actuated toward said core by the thermostatic action of said coil.

18. In an electric controlling device, the combination with an actuator, of a magnetic device forming part of the electric circuit to be controlled comprising a bimetallic coil, and a core connected to the inner end of said coil, the outer end of the coil and said core forming the terminals of said magnetic device, said actuator being operatively associated with said magnetic device to be actuated toward said core by the magnetic action of said core.

STEPHEN S. GRADY.

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