US1944832A

US1944832A - Circuit breaker

Info

Publication number: US1944832A
Application number: US403988A
Authority: US
Inventors: Gustav O Wilms; Trombetta Panfilo
Original assignee: Allen Bradley Co LLC
Current assignee: Allen Bradley Co LLC
Priority date: 1929-11-01
Filing date: 1929-11-01
Publication date: 1934-01-23
Anticipated expiration: 1951-01-23

Description

Jan. 23, 1934. G. o. WILMS ET AL CIRCUIT BREAKER I Original Filed Nov. 1, 1929 Jaw mm? 5 3 4 /2 z vT .l 1 2 i g i 5 2 5 3%? fi A a Q s? 22 w, x 9 i I] 6 m J J c, 4 m 0 ow o ww l l ||1||/ O a luw 5 W; 4 1. 2? G Hu .6 m H F F Patented Jan. 23, 1934 CIRCUIT BREAKER Gustav 0. Wilms and Panfilo Trombetta, Milwaukee, Wis., assignors, by mesne assignments, to Allen-Bradley Company, Milwaukee, Wis., a corporation of Wisconsin Application November ,1, 1929, Serial No. 403,988 Renewed June 14, 1933 24 Claims. (Cl. 200--124) This invention relates to a thermal circuit breaker of the type in which is employed a pawl and ratchet wheel latch having the ratchet wheel retained in a fixed position under normal conditions by a fusible binder.

The invention has as an object to provide a circuit breaker which is simple and eiiicient and which is positive and precise in operation.

Another object is to provide a circuit breaker in which the rate at which heat is delivered to the fusible binder may be readily adjusted to vary the conditions under which the latch will be released. v

Another object is to provide a circuit breaker which may be readily and economically manufactured.

According to the invention in its general aspect and as ordinarily embodied in practice, the circuit breaker is provided with an electric switch having a contact arranged in a stationary position and another contact arranged upon a movable contact carrier biased to an initial position, a heat insulated heat conductor extending through the contact carrier and carried thereby, a ratchet wheel arranged upon one side of the contact carrier and retained in a fixed position upon the heat conductor by a fusible binder, a pawl engaging the ratchet wheel and retaining the contact carrier in a predetermined position away from its initial position, an electric heater arranged upon the other side of the contact carrier to generate heat and transmit it through the heat conductor to the binder and thereby release the ratchet wheel.

The invention is exemplified by the circuit breaker illustrated in the accompanying drawing in which the views are as follows:

Fig. 1 is a top plan view with the top cover plate omitted, showing the circuit breaker closed and indicating the open position thereof by dotted lines.

Fig. 2 is a sectional front view taken on the line 2-2 of Fig. 1.

Fig. 3 is a bottom plan view with the bottom cover plate omitted.

The circuit breaker has its mechanism arranged within and carried by a casing 1 which is closed at its top by a removable cover plate 2 and at its bottom by a removable cover plate 3.

The cover plates are attached to the casing at one end thereof by a bolt or rivet 4 and at the other end thereof by a bolt 5 which may be retracted or withdrawn to permit one or both of the cover plates to be pivoted upon the rivet 4 and provide access to the circuit breaker mechanism.

The casing 1 has a terminal 6 and a terminal 7 arranged upon its outside and electrically connected, respectively, to a spring contact 8 and a spring contact 9 arranged upon its inside.

The spring contacts .8 and 9 are engaged, respectively, by

movable contacts

10 and 11 carried by a pivoted plate or contact carrier 12 connected by a pivot 13 to a lug 14 upon the casing 1.

The contact 10 is in continual engagement with the spring contact 8 which tends to swing the pivoted plate 12 upon its pivot 13 and move contact 11 out of engagement with spring contact 9, as shown in dotted lines in Fig. 1.

A heat conductor 15, shown as a tube of high heat conductivity such as copper, is carried by the pivoted plate 12 and heat insulated therefrom by an insulating bushing 16.

A ratchet wheel 1'7 is fixed on the upper end of the conductor 15 by a fusible binder 18, such as solder, and normally engaged by a catch or pawl 19 carried by the casing 1 to hold the

contacts

10 and 11 in engagement with the spring contacts 8 and 9, respectively.

The binder 18 is adapted to be fused to release the ratchet wheel 1'7 and permit the circuit br eakerto open, by heat transferred from an electric heater which is connected in the circuit to be controlled and arranged in thermal relation with the end of the conductor 15 on the opposite side of the pivoted plate to the ratchet wheel.

The electric heater may take any of the usual forms, such as a coil of resistance wire, but it is preferably a flat electric heater 20 connected between the

contacts

10 and 11.

The heater 20 is formed from a fiat strip of 90 resistance material, bent intermediate its ends to form a heating compartment 21, and apertured at its ends to receive the

screws

22 and 23 by means of which it is connected to the contacts 95 10 and 11.

An aperture 24, of greater diameter than the heat conductor 15, is formed in the heater 20 at the top of chamber 21 and the heat conductor 15 extends therethrough and into the chamber 21 100 but preferably does not contact with the heater 20.

Heat generated by the heater is radiated to the heat conductor 15 and conducted thereby to the fusible binder 18.

When the binder is fused, the spring contact 8 will swing the pivoted plate 12 on its pivot 13 and move the contact 11 out of engagement with the spring contact 9 to open the circuit, as shown in dotted lines in Fig. 1. 110

The binder 18 will then reharden to again bind the ratchet wheel 17 to the heat conductor 15 in a fixed position thereon.

When the circuit is open, a button 25 on the pivoted plate 12 extends through the front wall or the casing 1 and the circuit may be closed by pressing this button inward to swing the pivoted plate 12 on its pivot 13 and bring the contact 11 into engagement with the contact 9.

When a heating coil of resistance wire is employed, the end of the heat conductor 15 is arranged within the coil, but preferably out of contact therewith, and the heat characteristics of the circuit breaker are varied by varying the gauge of the wire, the number of turns in the coil, or the diameter of the coil relative to the diameter of the heat conductor.

When the heater 20 is employed, the heat characteristics of the circuit breaker may be varied by varying the cross-sectional area of the strip from which the heater is formed, the diameter of the aperture 24 relative to the diameter of the heat conductor 15, the diameter of the aperture 24 relative to the width of the strip, the width of the chamber 21, the depth of the chamber 21, or any combination of such variables.

Regardless of the type heater employed, heat radiated thereby will be absorbed by the conductor 15 and conducted to the fusible binder 18 to raise the temperature thereof.

Whenever a prohibitive overload occurs or a sufliciently large overload continues for a sufficient length of time, the temperature of the binder 18 is raised to the fusing point and then the ratchet wheel 17 released to allow the same to rotate on the heat conductor 15.

Heat produced under small and harmless overloads is radiated from the end portions of the heater, the contacts and 11, and the conductor so that the temperature of the binder 18 is not raised to the fusing point.

Under large or prohibitive overloads, the heat is generated so rapidly and conducted so quickly to the binder 18 that a sufficient amount thereof cannot be dissipated to delay fusing the binder and the circuit breaker is opened almost instantly.

Overloads intermediate these two extremes will cause temperature rises in the heater in proportion to the overload and the amount of heat dissipated to delay fusing the binder will be relative to the overload.

The electric heater 20 is readily accessible upon opening the casing on the side adjacent thereto, and then it may be readily removed from the pivoted plate or contact carrier and replaced either by itself or another electric heater of different characteristics.

The electric heater which is employed is given characteristics corresponding to the characteristics of the motor or other appliance to be protected.

The characteristics which the heater may be given are such that the circuit breaker will be opened almost instantly upon the occurrence of a predetermined high overload, or only upon the continuance of a lower overload for a predetermined period. a

The circuit breaker may be adapted to protect any motor by simply providing the same with a heater having heat characteristics corresponding to the characteristics of that motor.

The invention herein set forth is susceptible of various modifications without departing from the scope. thereof as hereafter claimed,

The invention is hereby claimed as follows:

1. A circuit breaker, comprising an automatically opening electric switch having stationary contacts for connection with the circuit to be controlled, a movable contact carrier having movable contacts arranged thereon to engage said stationary contacts, an electric heater arranged upon one side of said contact carrier and connected in series with said stationary and movable contacts, a heat conductor extending through said contact carrier to conduct heat from one side to the other side thereof and having one end in intimate thermal association with said heater, and a ratchet latch arranged upon the opposite side of said contact carrier to said heater to hold said switch closed and having a part thereof retained in a fixed position upon said heat conductor by a fiusible binder to keep said latch from being released until said binder is fused by heat from said heater.

2. A circuit breaker, comprising an automatically opening electric switch having stationary contacts for connection with the circuit to be controlled, a movable contact carrier having movable contacts arranged thereon to engage said stationary contacts, an electric heater arranged upon one side of said contact carrier and connected in series with said stationary and movable contacts, a heat conductor extending throughv said contact carrier and having one end thereof arranged in thermal relation to said heater to conduct heat therefrom, a ratchet wheel arranged upon the other side of said contact carrier and retained in a fixed position upon said heat conductor by a fusible binder,

and a pawl arranged to engage said ratchet wheel and hold said switch closed.

3. A circuit breaker comprising an automati cally opening switch for controlling an electric circuit, a flat electric heater connected into said circuit and having an opening therethrough intermediate the edges thereof, a heat conductor having a part thereof arranged in said opening, and a ratchet latch arranged to hold said switch closed and having a part thereof retained in a fixed position upon said heat conductor by a fusible binder.

4. A circuit breaker comprising an automatically opening switch for controlling an electric circuit, aflat electric heater connected into said circuit and having an opening therethrough intermediate the edges thereof, a heat conductor having one end thereof arranged in said opening, a ratchet wheel fixed on the other end of said heat conductor by a fusible binder, and a pawl to engage said ratchet wheel and hold said switch closed.

5. A circuit breaker comprising an automatically opening switch for controlling an electric circuit, a flat electric heater connected into said circuit and bent to form a heating compartment, a heat conductor having a part thereof arranged in said compartment and a ratchet latch arranged to hold said switch closed and having a part thereof retained in a fixed position upon said heat conductor by a fusible binder arranged between said latch and said conductor to normally hold said latch against relative movement.

6. A circuit breaker comprising an automatically opening switch having fixed contacts for connection into an electric circuit and movable contacts to engage said fixed contacts and comiii plete said circuit, an electric heater connecting said movable contacts and movable therewith, a heat conductor having one end thereof arranged in thermal association with said heater to conduct heat therefrom, a ratchet wheel fixed on the other end of said conductor by a fusible binder, and a pawl to engage said ratchet wheel and hold said switch closed.

'7. A circuit breaker comprising an automatically opening switch having fixed contacts for connection into an electric circuit and movable contacts to engage said fixed contacts and complete said circuit, an electric heater connecting said movable contacts and movable therewith, a heat conductor having one end thereof arranged in thermal relation with said-heater to conduct heat therefrom, a ratchet wheel fixed on the other end of said conductor by a fusible binder, a movable support for said movable contacts and said heat conductor arranged between said heater and said ratchet wheel and heat insulated from said heat conductor, and a pawl to engage said ratchet wheel and hold said switch closed.

8. A circuit breaker comprising two stationary spring contacts. a movable contact carrier, two movable contacts carried by said carrier to engage said spring contacts and close an electric circuit and repelled by said spring contacts to cause one of said spring contacts and its opposing movable contact to separate and open said circuit, an electric heater connected in said circuit, a heat conductor arranged in thermal relation with said heater to conduct heat therefrom, a ratchet wheel fixed on said heat con ductor by a fusible binder and spaced from said heater, and a pawl to engage said ratchet wheel and hold said switch closed.

9. A circuit breaker comprising two stationary spring contacts, a movable contact carrier, two movable contacts carried by said carrier to engage said spring contacts and close an electric circuit and repelled by said spring contacts to. cause one of said spring contacts and its opposing movable contact to separate and open said circuit, an electric heater connecting said movable contacts, a heat conductor arranged in thermal relation with said heater to conduct heat therefrom, a ratchet wheel fixed on said heat conductor by a fusible binder and spaced from said heater, and a pawl to engage said ratchet wheel and hold said switch closed.

10. A circuit breaker comprising two stationary spring contacts for connection into an electric circuit, two movable contacts carried by a pivoted contact carrier to engage said spring contacts, one of said spring contacts being in continual engagement with one of said movable contacts and tending to move said carrier and separate the other two contacts, a ratchet latch having a part thereof held against relative movement by a fusible binder to hold said movable con- 'tacts in engagement with said spring contacts, and an electric heater connected in said circuit to generate heat to fuse said binder and release said latch.

11. A circuit breaker comprising two stationary spring contacts for connection into an electric circuit, two movable contacts carried by a pivoted contact carrier to engage said spring contacts, one of said spring contacts being in continual engagement with one of said movable contacts and tending to move said carrier and separate the other two contacts, a ratchet latch having a part thereof held against relative movement by a fusible binder to hold said movable contacts in engagement with said spring contacts, and an electric heater connecting said movable contacts and adapted to generate heat to fuse said binder and release said latch.

12. A circuit breaker comprising two stationary spring contacts for connection into an electric circuit, two movable contactscarried by a pivoted contact carrier to engage said spring contacts, one of said spring contacts being in continual engagement with one of said movable contacts and tending to move said carrier and separate the other two contacts, an electric heater connected in said circuit, a heat conductor having a part thereof arranged in thermal relation with said heater to conduct heat therefrom, a ratchet wheel fixed on another part of said heat conductoriby a fusible binder, and a pawl to engage said ratchet wheel and hold said movable contacts in engagement with said stationary contacts.

13. A circuit breaker comprising two stationary spring contacts for connection into an electric circuit, two movable contacts carried by a pivoted contact carrier to engage said spring contacts, one of said spring contacts being in continual engagement with one of said movable contacts and tending to move said carrier and separate the other two contacts, an electric heater connecting said movable contacts, a heat conductor having a part thereof arranged in thermal relation with said heater to conduct heat therefrom, a ratchet wheel fixed on another part of said heat conductor by a fusible binder, and a pawl to engage said ratchet wheel and hold said movable contacts in engagement with said stationary contacts.

14. A circuit breaker comprising two stationary spring contacts for connection into an electric circuit, two movable contacts carried by a pivoted contact carrier to engage said spring contacts, one of said spring contacts being in continual engagement with one of said movable contacts and tending to move said carrier and separate the other two contacts, an electric heater connected in said circuit, a heat conductor having one end thereof arranged within said heater to conduct heat therefrom, a ratchet wheel fixed on the other end of said heat conductor by a fusible binder, and a pawl to engage said ratchet wheel and hold said movable contacts in engagement with said stationary contacts.

15. A circuit breaker comprising a casing, spring contacts arranged within said casing and having terminals arranged upon the outside of said casing for connection into an electric circuit, a contact carrier pivoted within said casing, movable contacts carried by said carrier to engage said spring contacts and close said circuit and repelled by said spring contacts to open said circuit, a heat conductor carried by said carrier, a ratchet wheel retained in a fixed position on said heat conductor by a fusible binder, a pawl to engage said ratchet Wheel and hold said movable contacts in engagement with said spring contacts, and an electric heater connected in said circuit and arranged in thermal relation with said heat conductor to heat the same and fuse said binder.

16. A circuit breaker, comprising a contact, a pivoted plate, a second contact carried by said pivoted plate, means for locking said pivoted plate in position so that said second contact engages said first contact, means for moving said plate into said locking position, thermally actuated means for releasirfg said locking means upon excessive flow of current through said contacts, one of said contacts also comprising spring means for moving said pivoted plate to snap open said contacts upon the release of said locking means.

1'7. A circuit breaker, comprising an electric switch tending to be opened by spring action between a movable contact and a stationary contact, a pawl and ratchet wheel latch associated therewith to keep said switch closed under normal current, a fusible binder retaining said ratchet wheel in a fixed position, and an electric heater connected in the circuit controlled by said switch and arranged to fuse said binder upon an abnormal current through said switch and thereby release said latch to permit'said switch to open.

18. A circuit breaker, comprising an electric switch tending to be opened by spring action between a movable contact and a stationary contact, a pivoted actuator carrying said movable contact, a pawl and ratchet wheel latch to keep said switch closed under normal current and having said ratchet wheel carried by said actuator and said pawl arranged in a stationary position, a fusible binder retaining said ratchet wheel in a fixed position, and an electric heater connected in the circuit controlled by said switch and arranged to fuse said binder upon an abnormal current through said switch and thereby release said latch to permit said switch to open.

19. A circuit breaker, comprising a self-opening switch, a flat electric heater connected in circuit with said switch and bent intermediate the ends thereof to form a heating compartment and having an aperture formed therein at one end of said compartment, a heat conductor extending through said aperture into said compartment, a ratchet wheel spaced from said electric heater and fixed upon said heat conductor by a fusible binder arranged between the same, and a pawl to engage said ratchet wheel and hold said switch closed.

20. A circuit breaker, comprising a supporting frame,-a plate pivoted upon said frame and spring biased toward a given position, an electric switch having a stationary contact carried by said frame and a movable contact carried by said plate, a heat insulated heat conductor extending through said plate to conduct heat from one side to the other side thereof, a ratchet wheel arranged upon one side of said plate and fixed upon said heat conductor by a fusible binder, a pawl carried by said frame and normally engaging said ratchet wheel to retain said plate in a different position, an electric heater connected into an electric circuit and arranged upon the other side of said plate in intimate thermal association with said heat conductor to generate heat and transmit the same through said heat conductor to said binder to thereby fuse said binder and release said ratchet wheel upon the pe of an excessive current through said heater.

21. A circuit breaker, comprising a movable contact carrier provided with a switch contact engageable with another contact and urged to an initial position by spring action between said contacts, a heat conductor extending through said contact carrier from one side to the other side thereof and heat insulated therefrom, a ratchet wheel carried by said heat conductor upon one side of said contact carrier and retained in a fixed position upon said heat conductor by a fusible binder, an electric heater arranged upon the other side of said contact carrier in thermal relation to said heat conductor, and a pawl engageable with said ratchet wheel to retain said contact carrier in a predetermined position away from its initial position.

22. A circuit breaker, comprising a movable contact carrier provided with a switch contact engageable with another contact, a heat conductor carried by said contact carrier, an electric heater carried by said contact carrier and arranged in thermal relation with said heat conductor, a ratchet wheel retained in a fixed position upon said heat conductor by a fusible binder, and a pawl arranged to engage said ratchet wheel to retain said contact carrier in position to engage said switch contacts.

23. A circuit breaker, comprising a movable contact carrier provided with two movable switch contacts engageable with corresponding stationary contacts, a heat conductor carried by said contact carrier, an electric heater arranged in thermal relation to said heat conductor and connected between said movable contacts, a ratchet wheel retained in a fixed position upon said heat conductor by a fusible binder, and a pawl arranged to engage said ratchet wheel to retain said contact carrier in position to engage said movable contacts with said stationary contacts.

24. A circuit breaker, comprising a movable contact carrier provided with two movable switch contacts engageable with corresponding stationary contacts, a heat conductor carried by said contact carrier and extending therethrough from one side to the other side thereof, an electric heater arranged in thermal relation with said heat conductor upon one side of 'said contact carrier and connected in circuit between said movable contacts, a ratchet Wheel arranged upon the other side of said contact carrier and re- -tained in a fixed position upon said heat conductor by a fusible binder, and a pawl arranged to engage said ratchet wheel to retain said contact carrier in position to engage said movable contacts with said stationary contacts.

GUSTAV O. WILMS. PANFILO 'I'ROIVIBETIA.

CERTIFICATE or CORRECTION.

Patent No. 1,944,832; January 23, 1934.

GUSTAV 0. WILMS, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, lines 143, 14.4 and 145, claim 5, strike out the words "arranged between said latch and said conductor to normally hold said latch against relative movement"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 20th day of March, A. D. 1934.

F. M. Hopkins (Seal) Acting Commissioner of Patents.