US2429225A

US2429225A - Thermal circuit breaker

Info

Publication number: US2429225A
Application number: US608053A
Authority: US
Inventors: Stephen S Grady
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-07-31
Filing date: 1945-07-31
Publication date: 1947-10-21
Anticipated expiration: 1964-10-21

Description

Oct. 2l, 1947. s, 5 GRADY ,THERMAL CIRCUIT BREAKER File'd Juiy 31, 1945 NTOR . @Wwf lll l.

ATTORNEY Patented Oct. 2l, 1947 UNITED vSTATES" PATENT OFFICE 9 Claims. (Cl. 200-116) This invention relates t circuit breakers in general.

Among the objects of the present invention, it is aimed to provide an improved circuit breaker relying upon a bi-metal deflector sensitive to heat in case of an overload to initiate the break or interruption in the circuit thereby to afford protection to the apparatus and to avoid well known hazards and damage resulting from an overload in a circuit.

It is still another object of the present invention to provide an improved circuit breaker which includes a snap or quick acting switch for interrupting a current in case of an overload, which switch however can quickly be reset after the abnormal .condition has been overcome, ready for another emergency.

The invention still further contemplates an improved circuit breaker comprising a quick acting switch which will instantaneously,interrupt the current when an overload occurs initiated by the deection of a bi-metal thermostat and at the same time actuate an insulating shield into the gap formed between the main contacts when the interruption is effected,

These and other features, capabilities and advantages of the invention will appear from the subjoined detail description of one specic embodiment thereof illustrated in the accompanying drawings in which Fig. l. is a plan View of a container or panel having mounted therein a number of circuit breakers made according to the present invention;

Fig. 2 is a section on the line 2-2 of Fig. l;

Fig. 3 is a front elevation of one of the circuit lbreakers as a unit partly in section and slightly enlarged as to the scale of Fig. l;

Fig. 4 is a rear elevation of the unit shown in Fig. 3 partly in section;

Fig, 5 is a section on the line 5--5 of Fig. 3;

Fig. 6 is a front elevation of the unit with the circuit breaker in circuit interrupting position;

Fig. 7 is a front elevation of a unit after an overload has actuated the switch to interrupt the circuit;

Fig. 8 is a section on the line 8-8 of Fig. 3.

In the present embodiment, there is provided an insulating block having a base l and an upright 2. Secured to the'lower face of the base I `largement Ii on the arm 5.

there is 'provided a bracket 3 having an arm 4, Figs. 3 and 8, constituting one terminal of the switch or circuit breaker. The bracket 3 also has an upright 5 provided with an enlargement 6 to constitute the xed contact of the circuit breaker. To the lower face of the base I there is also secured the bracket 'I having the arm 8, Figs. 4 and 8, constituting the other terminal of the circuit breaker. The bracket 'I has upwardly extending therefrom the bi-metal thermostat 9 which is connected by the flexible conductor I0 to the centrally disposed supporting plate II, the flexible conductor IIJ being connected to the arm I2 of the plate I I. The plate I I is secured by the flange I I0 to the upper face of the base I, see Fig. 5. The plate II has an abutment I3 formed thereon to which there is secured a coil of the wire spring I4, one end of which, to wit the end I5, is preferably secured in the base I and the arm I6 of which spring I4 has a linger II to engage the shoulder I8 on the steel section I9 of the bi-metal thermostat 9. The arm I6 has an elbow 20 and adjacent to same a cam face 2I to cooperate with the shoulder 22 on the blade 23 pivoted at 24 to the plate Il adjacent to the base I, The blade 23, see Fig. 5, has a cross-piece 25 and an extension 26 extending down one face of the plate II while the main part of the blade 23 extending up from the pivot kpin 2-4 extends along the other face of the plate Il. The extension 26 has a projection 21 to which is connected one end of the spring 28, the other end of which is connected to the pin 29 adjacent to the free end rof the L-shaped lever 30. The pin 29 in the present instance is disposed substantially at the intersection of the arms 3l and 32 of the lever 30. The lever 30 is pivotally connected by the pin 33 to the plate II. The arm 32 preferably has an enlargement 34 at the end thereof constituting the contact element to engage the contact en- The spring 28 will cooperate with the blade 23 and arm 3| to form a snap or toggle switch, the spring being disposed to one side of the pivot pin 33 of the arm 30 in contact making position and to the other side of the pivot pin 33 in contact breaking or open position of the circuit.

The upright 2 has a slot therein to receive the insulating gate 35 which in lowered position, that shown in Fig, 6, cooperates with the flange 36 effectively to close the gap between the contact 6 and the contact 34. The gate 35 has an opening |36 therein to receive the finger or projection 31 formed on and extending from the upper end oi the arm 3| of the plate 30. The plate or lever Si) also has a resetting finger 38, Figs. 3, 4, 6 and '1, extending at right angles to the main part of the plate 30 and into the area above the finger I1 and to one side of the elbow 20 of the arm I6.

Preferably the plate II, see Fig. 4, has two

extensions

39 and 48. The extension 40 may serve as a limiting stop for the blade 23, see the position of the extension 28 of the blade 23, in engagement with the shoulder 40 in Fig. 4, in contactl making position when the spring finger I1 engages the shoulder I8 of the bi-metal thermostat fi. In such position, the finger 4I on the lower end of the blade 23 adjacent its pivot pin 24 may also engage the upper edge of the arm 32 of the lever 3B, see Figs. 3 and 4. The eXtension 39, on the other hand, may serve as a limiting stop for the plate 23 in circuit breaking position.

In operation, to set the finger I1 it is only necessary to move the blade 23 from the position in Fig. '1 into position shown where the elbow 2Q will engage the cam face 22 and depress the iinger I1 into engagement with the shoulder I8, see Fig. 6. Thereupon the blade 23 may be swung back into the position shown in Fig. 3, when due to the action of the spring 28, the contact 34 is brought into engagement with the contact 6. At the same time, the spring 28 will cause the lever 3U through its finger 31 to raise the gate 35 into the position shown in Fig. 3 where the gap will be formed and the arm 32 will extend under the gate 35 and over the shoulder 36 to enable its contact 34 to engage the contact 6.

In the position illustrated in Fig. 3, the circuit breaker is ready for operation. Should an overload arise and the overload continue long enough to affect the thermostat 9 to deiiect it, it will release the finger I1 due to the spring tension in the spring arm I6, cause the finger I1 to rise or snap upward to engage the finger 38 and thrust it upward in turn to rock the lever 30 to swing the spring 28 into position where it will withdraw its arm 32 out of the gap beneath the gate 35, at the same time withdraw the contact 34 from the contact 6, and at the same time cause the finger 31 to lower the gate 35 into gap closing position.

If the abnormal condition ceases and it is desired again to close the circuit, it is only necessary to swing the blade 23 back into the position shown in Fig. 6 where it will reset the nger I1 in engagement with the shoulder I8, whereupon the blade 23 may be swung over into position where it will cause the Contact 34 to engage the contact 6 and raise the gate 35 out of the gap between the

contacts

34 and 6. In normal contact making position, when the finger I1 engages the shoulder I8, the current will pass from the bracket 3 to the contact 6 and from the contact 6 to the contact 34 and then through the lever 38 to its pivot pin 33 and from its pivot pin 33 through the plate II to the fiexible conductor I0, from the fiexible conductor I to the thermostat 9 and from the thermostat 9 to the bracket 1.

Preferably to facilitate actuating the blade 23, the upper end of the plate 23 is provided with an insulating finger piece 42. The cross-piece 25 of the blade 23 in turn is positioned to move across the insulating strip 43 secured to the

extensions

39 and 40 on the plate I I.

Preferably, especially when the circuit breakers are mounted in a box with other circuit breakers, an insulated housing is provided having two side walls 44 and 45 connected to the end wall 48 which are secured to the base I and have an arcuate top wall 41 provided with a slot 48 to clear the neck 49 of the finger piece 42. The end wall 46 is disposed adjacent the thermostat 9. The other end wall 50 extends down from the arcuate wall 41 to the contact 6, see Fig. 3. The circuit breakers so housed, see Figs. 1 and 2, are then mounted upon the base 5I of the panel which is provided with

side walls

52 and 53 and a cover 54 having openings therein to clear the upper portions of the individual

circuit breaker housings

55 and 56 as shown in Fig. 2.

In the present instance, adjacent to the thermostat blade 9, there is provided the extension or upright 51, preferably integral with the base 1. The thermostat 9 is so constructed that when it is heated due to an overload, it will deflect toward the extension or upright 51. If the heat is sufficient to cause the blade 9 to deflect far enough, in turn to cause its upper edge to engage the extension 51, then the current will be shunted to pass from the conductor I0 through the upper edge of the blade 9 to the extension 51 and thereby relieve the blade 9 in turn to prevent it from being overheated.

Obviously, the bi-metal thermostat 9 may be made of any of the two different metals conventionally used instead of copper and steel.

It is obvious that various changes and modifications may be made to the details of construction without departing from the general spirit of the invention as set forth in the appended claims.

I claim:

1. The combination of a fixed contact, a pivotally mounted plate having a movable contact for engagement with said fixed Contact, a spring controlled blade forming a toggle with said plate for actuating said plate into circuit making and circuit breaking position, a finger on said plate, a spring actuator for engaging said finger and rocking said plate into circuit breaking position,

and a bi-metal thermostat normally anchoring said spring actuator out of engagement with said finger, said thermostat being connected to the circuit under control and sensitive to an overload to free said spring actuator and allow said spring actuator to actuate said finger in turn to withdraw the movable contact out of engagement with said fixed contact.

2. The combination of a fixed contact, a pivotally mounted plate having a movable contact for engagement with said fixed contact, a spring controlled blade forming a toggle with said plate for actuating said plate into circuit making and circuit breaking position, a finger on said plate, a spring actuator for engaging said finger and rocking said plate into circuit breaking position, a bi-metal thermostat normally anchoring said spring actuator out of engagement with said finger, said thermostat being connected to the circuit under control and sensitive to an overload to free said spring actuator and allow said spring actuator to actuate said finger in turn to withdraw the movable Contact out of engagement with said fixed contact, and a handle operatively connected to said toggle to actuate said plate and movable contact into and out of circuit making position.

3. The combination of a fixed contact, a pivotally mounted plate having a movable contact for engagement with said fixed contact, a spring controlled blade forming a toggle with said plate for actuating said plate into circuit making and circuit breaking position, a finger on said plate, a spring actuator for engaging said finger and rocking said plate into circuit breaking position, a bi-metal thermostat normally anchoring said spring actuator out of engagement with said finger, said thermostat being connected' to the circuit under control and sensitive to an overload to free said spring actuator and allow said spring actuator to actuate said finger in turn to withdraw the movable contact out of engagement with said fixed contact, said blade including a shoulder, and a handle connected to said blade for actuating said blade into circuit breaking position to enable said shoulder to reset said spring actuator into anchoring engagement with said thermostat.

4. The combination of a fixed contact, a pivotally mounted plate having a movable contact for engagement with said fixed contact, a pivotally mounted blade, a spring operatively connecting said plate and blade to form a quick acting toggle to actuate said movable contact into or out of circuit making position, a finger on said plate, a spring actuator, a thermostat in the electric circuit normally anchoring said spring actuator, said thermostat being deflected in case of an overload to free the spring actuator and enable it to actuate said finger in turn to actuate said plate into circuit breaking position, and a shoulder on said blade cooperating with said spring actuator to reset it into anchoring engagement with said thermostat upon actuation of said blade.

5. The combination of a fiXed contact, a Divotally mounted plate having a movable contact for engagement with said fixed contact, a spring controlled blade forming a toggle with said plate for actuating said plate into circuit making and circuit breaking position, a first finger on said plate, a spring actuator for engaging said first finger and rocking said plate into circuit breaking position, a bi-metal thermostat normally anchoring said spring actuator out of engagement with said first finger, said thermostat being connected to the circuit under control and sensitive to an overload to free said spring actuator and allow said spring actuator to actuate said finger in turn to withdraw the movable contact out of engagement with said fixed contact, an insulating gate slidably mounted between said xed contact and said movable contact, and a second finger integral with said plate engaging said gate upon the actuation of said plate to move said gate into position between said fixed contact and movable contact in circuit breaking position and to clear the gap between such contacts in circuit making position.

6. The combination of an insulated housing, a fixed contact for an electric circuit formed on the outside of said housing, a bearing plate disposed inside of said housing, a second plate pivotally mounted on said bearing plate and having a movable contact actuatable to extend from said housing into engagement with said fixed contact in circuit making position, a blade pivotally connested to said bearing plate, a spring operatively connecting said blade and said second plate to form a quick acting toggle to actuate said movable contact into or out of circuit making position, a thermostat in the circuit, conductively connected to said movable contact, a spring actuator normally anchored by said thermostat, a finger on said second plate, and a shoulder on said blade in position to actuate said spring active to an overload to deflect and thereby to free said spring actuator and allow said spring actuator to actuate said finger in turn to withdraw the movable contact outy of engagement with said fixed contact.

7. The combination of a fixed contact for an electric circuit, a bearing plate, a second plate pivotally mounted on said bearing plate and having a movable contact for engagement with said fixed Contact in circuit making position, a blade pivotally connected to said bearing plate, a spring operatively connecting said blade and said second plate to form a quick acting toggle to actuate said 'movable contact into or out of circuit making position, a thermostat conductively connected to said bearing plate, a spring actuator normally anchored by said thermostat, a finger on said second plate, and a shoulder on said blade in position to actuate said spring actuator to reset the same in anchoring relation with said thermostat, said thermostat being sensitive to an overload to deflect and thereby to free said spring actuator and allow said spring actuator to actuate said finger in turn to withdraw the movable contact out of engagement with said fixed contact.

8. The combination of an insulated housing, a fixed contact for an electric circuit disposed on the outside of said housing, a bearing plate on the inside of said housing, a second plate pivotally mounted on said bearing plate and having a movable contact actuatable to extend from said housing into engagement with said fixed contact in circuit making position, a blade pivotally connected to said bearing plate, a spring operatively connecting said blade and said second plate to form a quick acting toggle to actuate said movable contact into or out of circuit making position, a bi-metal thermostat conductively connected to said bearing plate, a shoulder on said thermostat, a spring actuator normally engaging said shoulder and anchored thereby, a rst finger on said second plate, and a cam shoulder on said blade in position to actuate said spring actuator to reset the same in anchoring relation, said thermostat being sensitive to an overload to defiect and in turn free said spring actuator from said shoulder, and allow said spring actuator to actuate said first finger in turn to withdraw the movable contact out of engagement with said fixed contact an insulating gate slidably mounted between said xed contact and said movable contact, and a second finger on said plate in engagement with said gate upon the actuation of said plate to move said gate into position between said fixed contact and movable contact in circuit breaking position and to clear the gap between said contacts in circuit making position.

9. The combination of a fixed contact, a pivotally mounted plate having a movable contact for engagement with said fixed contact to close an electric circuit, a pivotally mounted blade, a spring operatively connecting said plate and blade to form a quick acting toggle toiactuate said movable contact into or out of circuit making position, a first finger on said plate, a spring actuator, a thermostat in the electric circuit normally Yanchoring said spring actuator, said thermostat being deflected in case of an overload to free the spring actuator and enable it to actuate said rst finger in turn to actuate said plate into circuit breaking position; a shoulder on said blade cooperating with said spring actuator to reset it into anchoring engagement with said thermostat REFERENCES CITED The following references are of record in the file of this patent:

Number Number UNITED STATES PATENTS Name Date Grady July 20, 1943 Taylor May 16, 1939 Guett July 17, 1934 FOREIGN PATENTS Country Date Great Britain 1914