US2806103A - Circuit breaker - Google Patents

Description

p 0, 1957 F. GELZHEISER 2,806,103

CIRCUIT BREAKER 3 Sheets-Sheet 1 Filed Jan. 21, 1954 43 OFF Fig.2.

Fig.l.

43 OFF Fig. 3

INVENTOR Francis L.Gelzheiser BYQ/ Wfi -W|TNESSES:

p 1957 F. L. GELZHEISER 2,806,103

cmcun BREAKER Filed Jan. 21, 1954 5 Sheets-Sheet 2 Sept 10, 1957 F. L. GELZHEISER 2,

CIRCUIT BREAKER Filed Jan. 21, 1954 5 Sheets-Sheet 3 Fig. 8.

United States Patent Ofilice CIRCUIT BREAKER Francis L. Geizlieiser, Beaver, Pa., assignor t Westinghouse Electric Corporation, a corporation of Pennsyl- Vania Application Eanuary 21, 1954, Serial No. 405,320 10 Claims. (Cl. 200-88) This invention relates to circuit breakers and, more particularly, to circuit breakers that are manually oper* ated to open and closed positions and are automatically tripped open in response to overload currents.

An object of the invention is to provide a circuit breaker embodying improved means for causing opening and closing of the breaker contacts with a snap action.

Another object of the invention is to provide a circuit breaker having few parts, which parts are easy to assemble.

Another object of the invention is to provide a circuit breaker of simple construction, that is reliable in operation and inexpensive to manufacture.

The invention, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description thereof when read in conjunction with the accompanying drawing:

In said drawing:

Figure 1 is a side elevational view of a circuit breaker embodying the principles of the invention, the breaker being shown with the cover largely broken away and with the mechanism in the manually open position.

Fig. 2 is a view similar to Fig. 1, but showing the mechanism in the closed position.

Fig. 3 is similar to Figs. 1 and 2, but showing the mechanism in the tripped open position.

Fig. 4 is a side elevational view of a circuit breaker similar to that shown in the Figs. 1 to 3 modification, the breaker being shown with the cover removed and with the mechanism in the closed position.

Fig. 5 is a View similar to Fig. 4, but showing the mechanism in the manually opened position.

Fig. 6 is a view similar to Figs. 4 and 5, but showing the mechanism in the tripped open position.

Fig. 7 is a vertical sectional view taken substantially along line VII-NH of .Fig. 4 and looking in the direction of the arrows.

Fig. 8 is a horizontal sectional view taken on line VIII-VIII of Fig. 4 and looking in the direction of the )BITOWS.

Referring to Figs. 1 to 3 of the drawings, the circuit breaker is enclosed in a housing comprising an opensided housing 11 and a cover plate 13 both of molded insulating material. The cover plate is shown broken away for clearness. A stationary contact 15 is rigidly mounted on the inner end of a conductor 17 which extends out through a suitable opening in the end wall of the housing 11 and has a connecting means 19 at its outer end for connecting the circuit breaker in an electric circuit.

A movable contact 21 is rigidly mounted on a movable switch member or contact bar 23 pivotally supported on a pivot pin 25 mounted in the side wall of the housing 11. Also pivotally mounted on the pivot pin 25 is an actuator 27 for moving the switch member 23 to open and close the contacts. The switch member 23 and the actuator 27 extend substantially in opposite direction from their common pivot 25 and are normally latched together by 2,806,103 Patented Sept. 10, 1957 means of a bimetal element 29 welded or otherwise suitably secured to the switch member 23 adjacent the pivot 25. The bimetal element 29 extends along the actuator 27 and has a formed-over latch portion 31 which is normally in latching engagement with the edge of the actuator 27. The switch member 23 is biased in opening direction by means of a spring 33 coiled about the pivot pin 25 and having one of its ends hooked over the edge of the actuator 27. The other end of the spring 33 is hooked over the edge of the switch member 23 and biases the switch member counterclockwise in opening direction relative to the actuator 27 Movement of the switch member 23 in opening direction is normally prevented by engagement of the latch portion 31 of the bimetal element 29 with the actuator 27.

The actuator 27 and, due to the latch 31 and bimetal element 29, the switch member are biased to the closed contact position (Fig. 2) by means of a coil spring 35 disposed under compression between the outer end of the actuator 27 and the inner end of an operating lever 37 pivotally supported on a pin 39 in an opening 41 in the wall of the housing member 11. The operating lever 37 extends outwardly through the opening 41 and terminates in a manual operating handle 43. The ends of spring 35 are snugly coiled about spring guides 45 and 47, respectively, on the outer end of the actuator 27 and the inner end of the operating lever 37.

The outer end of the bimetal element is connected in the circuit through the breaker contacts by means of a flexible conductor 49 having one end connected to the bimetal and the other end connected to the inner end of a conductor 51 which extends out through an opening in the wall of the housing 11 and has a terminal connector 53 at its outer end for connecting the circuit breaker in an electric circuit.

Since the spring 35 is under initial compression, it biases the actuator 27 and the switch member clockwise to the closed position (Fig. 2) and biases the operating lever 37 counterclockwise to the on position. The contacts are manually opened by moving the operating lever 37 clockwise from its Fig. 2 position to the position shown in Fig. 1. This moves the operating spring 35 over center to the left of a line through the pivots 25-39 whereupon the spring 35 biases the actuator 27 counterclockwise to its open position and biases the handle clockwise to the o position. The opening movement of the mechanism is eifected with a snap action and is limited as shown in Fig. 1, by engagement of the switch member 23 with a portion 55 of the casing 11.

The contacts are closed manually by reverse movement of the operating lever 37, that is, counterclockwise from the off position (Fig. 1) to the on position (Fig. 2). The over center movement of the operating spring 35 causes the mechanism to close the contacts with a snap action.

The circuit breaker is automatically tripped open free of the operating mechanism by the unlatching action of the bimetal element 29 when it is heated a predetermined amount in response to an overload current. When suiiiciently the bimetal element 29 bends in a direction to disengage the latch 31 from the actuator 27 whereupon the spring 33 snaps the switch member 23 counterclockwise to the open position as shown in Fig. 3.

In the closed position of the circuit breaker (Fig. 2) the clockwise movement of the actuator 27 is limited by the latch 31 and the engagement of the movable contact 21 with the stationary contact 15. When the bi metal element 29 deflects and disengages the latch 31, the spring 35 biases actuator 27 in a clockwise direction, the movement being limited by engagement of the actuator with a stop stud 57 in the side wall of the casing 11.

When the breaker is tripped open and the actuator 27 moves into engagement with the stop stud 57 the additional expansion of the spring 35 causes the handle 43 to move beyond the on position to give an indication that the breaker has been tripped open.

Before the contacts can be closed following an automatic tripping operation it is necessary to relatch the switch member 23 to the actuator 27. With the parts in the tripped open position (Fig. 3) the actuator 27 is moved counterclockwise to its manually open position (Fig. l) by appropriate movement of the operating lever 37. During the counterclockwise movement the latch member 31 bears against the side of the actuator 27 due to the inherent resiliency of the bimetal element. As the actuator moves beyond the latch 31 the latch snaps into position back of the actuator as shown in Fig. l. The contacts are then closed by manually moving the handle 43 counterclockwise to the on position closing the contacts in the perviously described manner.

According to the modification shown in Figs. 4 to 8 there is provided electroresponsive means for disengaging the bimetal element from the latch to effect instantaneous opening of the breaker in response to high overload currents or short circuit currents.

Referring to Fig. 4, the circuit breaker comprises a housing 61 and a cover 63 (Figs. 7 and 8) therefor both made of molded insulating material, the circuit breaker being shown in Figs. 4, and 6 with the cover removed, a stationary contact 65, a movable contact 67, operating means 69 and a trip device 71. V

The stationary contact 65 is rigidly secured to the inner end of a conducting member 73 integral with a plug-in connector member 75 which is suitably supported in matching recesses in the housing 61 and the cover 63.

The movable contact 67 is rigidly mounted on a movable switch member or contact arm 77 pivotally supported on a pivot portion 79 integral in the side wall of the housing Also mounted on the portion 79 is an actuator 81 of insulating material for moving the switch member 77 to open and close the contacts. The switch member 77 and the actuator 81 are normally releasably latched together by means of a bimetal element 33 welded or otherwise suitably secured to the switch member '77 adjacent the pivot means 79. The bimetal element 33 extends along the actuator 31 and one edge thereof normally releasably engages a latch element 85 on the actuator 81. The switch member 77 is biased in opening direction by means of a spring S7 coiled about the pivot 79 and having one of its ends hooked over the edge o the actuator 31. The other end of the spring 87 engages an opening 89 in the switch member 77 and biases the switch member counterclockwise in opening direction relative to the actuator 81. Movement of the switch member 77 in opening direction is normally prevented by engagement of the bimetal element 83 with the latch 85 on the actuator 81. V

The actuator 31 and, due to the engagement of the bimetal element 33 with the latch 85, the switch mem-' bers are biased to the closed position (Fig. 4) by means of a coil spring 91 arranged under compression between the outer end of the actuator 81 and an operating handle One end of the spring 91 is looped around a spring retainer 95 secured to the end of the actuator 81 and the other enl is seated in a spring seat in the handle 93.

The handle 93 is arcuate in shape and has a finger 99 in the housing 61.

which exte out through an opening in the adjacent end wall of the housing 11 and has a terminal connector 109 at its outer end for connecting the circuit breaker in an electrical circuit.

Since the operating spring 91 is under initial compression, it biases the actuator 81 and, through the latch and bimetal 83, the switch member or contact arm 77 clockwise to the closed position (Fig. 4) and biases the handle 93 counterclockwise to the on position. The contacts are manually opened by moving the op erating handle 93 clockwise from its Fig. 4 position to its Fig. 5 position. This moves the line of action of the operating spring 91 over center to the right of center line of the actuator 81 whereupon the spring 91 biases the actuator 81 counterclockwise to the open position and biases the handle 93 clockwise to the OE position. The opening movement of the mechanism is efiected with a snap action and is limited, as shown in Fig. 5, by engagement of the actuator 81 with a shoulder 111 on the housing 61.

The contacts are closed manually by reverse movement of the handle 93, that is, counterclockwise from the ott position (Fig. 5) to the on position (Fig. 4). The overcenter movement of the operating spring 91 causes the mechanism to close the contacts with a snap action. V

The circuit breaker is automatically tripped open free of the operating mechanism by operation of the trip device 71 which includes the bimetal element 83. The trip device also includes an electromagnet for instantaneously tripping the breaker in response to short circuit currents. The electromagnet comprises a fixed magnet yoke 113 disposed in a recess 115 in the housing 61 and surrounding three sides of the terminal conductor 107. One leg 117 of the magnet yoke 113 (Fig. 8) is longer than the other leg and is provided with a reduced portion 119 which extends through an opening in an armature 121 for pivotally supporting an armature. The armature 121 is provided with a portion 123 formed at an angle to the main armature and having its end disposed adjacent the bimetal element at the high expansion side thereof..

A spring 125 secured to the armature 121 biases the armature to its unattracted position in which the portion 123 lies against a shoulder 127 on the housing 61.

' Upon the occurrence of an overload current below a predetermined value of, for instance, ten times normal rated current, the bimetal element 83 becomes heated and when heated sufliciently bends in a direction to disengage itself from the latch member 85. When this occurs the spring 87 snaps the switch member 77 counterclockwise to the open position as shown in Fig. 6, where it is arrested by the engagement of a projection 129 thereon with a shoulder 131 on the housing 61. When the bimetal element83 is released from the latch 85 the spring 87 biases the actuator 81 against a shoulder 133 on the housing 61.

An extension 135 (Figs. 4, 5, 6 and 7) suitably rigidly secured to the actuator 31 extends into a slot 137 in the inner portion of the handle 93. In the closed position of the breaker (Fig. 4) the operating spring 91 biases the handle 93 to its extreme on position and the actuator 81 and, through the latch 85, the bimetal 83 and switch member 77 to the closed position. In the closed position of the breaker the extension 135 does not engage the end wall 139 of the slot 137, the force of the spring 91 being between the end 99' of the opening 99 in the housing 61 and the breaker contacts to thereby provide contact pressure. When the bimetal element 83 is released from the latch member 85 and the spring 87 biases the actuator 81 against the shoulder 133, the relative movement of the actuator extension 135 and the handle 93 under the influence of spring 91 is limited by engagement of the end Wall 139 of the slot 137 with the extension 135. In this position (Fig. 6) the finger piece 917 of the handle occupies a trip indicating position.

Before the contacts can be closed following an automath: tripping operation, it is necessary to reset and relatch the mechanism. This is accomplished by moving the handle 93 clockwise from its Fig. 6 position to the oil position, as shown in Fig. 5. This movement of the handle to the ott position permits movement of the line of action of the operating spring 91 over to the right of the center line of the actuator 81 whereupon the spring 91 moves the actuator counterclockwise against the stop 111, as shown in Fig. 5. If, at this time, the bimetal element 83 has cooled, it will spring back into latching relation with the latch member 85. The contacts are then closed in the previously described means by counterclockwise movement of the handle 93 to its Fig. 4 position.

Upon the occurrence of an overload current above ten times normal rated current or ;a short circuit current, the tripping electromagnet is energized by the current flowing in the conductor 107 sufiiciently to attract the armature 121 to the magnet yoke 113. This movement of the armature 121 causes the portion 123 thereof to strike the bimetal element '33 and disengage it from the latch element 85 whereupon the spring 87 as previously described instantaneously moves the switch member 77 together with the bimetal element '83 to the open position, as shown in Fig. 6. The mechanism is reset and the contacts are closed following an instantaneous tripping operation in the previously described manner.

The hot arc gases are vented through a passage 141 and out a vent 143 at the opposite end of the breaker housing from the breaker contacts. The passage 141 is formed by walls 145 and 147 molded integral with housing 61 and closed by the cover 63.

Having described the invention in accordance with the provisions of the patent statutes, it is to be understood that various changes and modifications may be made in the structural details thereof without departing from some of the essential features of the invention.

I claim as my invention:

1. In a circuit breaker having relatively movable contacts, a pivoted switch member pivoted at one end and biased open and movable to open and close said contacts, an actuator having one end pivoted and the other end free for moving said switch member to open and closed positions, said switch member and said actuator extending in substantially opposite directions, a bimetallic latch rigidly mounted on said switch member at the pivoted end thereof and releasably engaging said actuator, a pivoted operating handle, an operating spring compressed between the one end of the operating handle and the free end of said actuator, said operating spring being operable by said handle to cause opening and closing movement of said actuator and said switch member, and thermal bending of said bimetallic latch releasing said switch member to permit opening movement of said switch member.

2. In a circuit breaker comprising relatively movable contacts, a movable switch member pivoted at one end for opening and closing said contacts, an actuator for said movable switch member having one end pivoted and the other end free and having -a spring guide on the free end thereof, an operating handle having a spring guide hereon adjacent the spring guide on said actuator, a coil spring compressed between the free end of said actuator and one end of said handle and having its ends surrounding said spring guides, said coil spring being operable by said handle to move said actuator and said switch member to open and closed positions, biasing means biasing said switch member in opening direction relative to said actuator, a bimetal element mounted on said switch member at the pivoted end thereof and having a portion releasably engaging said actuator to re leasably restrain said switch member from movement relative to said actuator, and thermal bending of: said bimetal element releasing said switch member from said actuator to permit said biasing means to move said switch member to open position free of said actuator.

3. In a circuit breaker having relatively movable contacts, a pivoted switch member movable to open and close said contacts, a pivoted actuator for moving said switch member, manual operating means comprising a handle and a spring compressed between said actuator and said handle for operating said actuator, a common fixed pivot supporting said switch member and said actuator, said switch member and said actuator extending substantially in opposite directions from said pivot, a spring biasing said actuator and said switch member in opposite directions about said common pivot and biasing said switch member to open position, a bimetal element rigidly mounted on said switch member at said pivot extending substantially parallel to and in the opposite direction from said switch member, a latching portion on said bimetal element engaging said actuator to normally releasably restrain said switch member in closed position, and thermal bending of said bimetal element causing said latch portion to disengage said actuator to permit said biasing means to move said switch member to open position.

4. In a circuit breaker having relatively movable contacts, a switch member pivoted at one end and biased open and movable to open and close said contacts, a pivoted actuator having one end free for moving said switch member to open and closed positions, said switch member and said actuator extending in substantially opposite directions, a bimetallic latch rigidly mounted on said switch member at the pivoted end thereof and releasably engaging said actuator, a pivoted operating handle, an operating spring compressed between one end of the operating handle and the free end of said actuator, said operating spring biasing said contacts closed in the closed position and biasing said contacts open in the open position, said operating spring being operable by said handle to cause opening and closing movement of said actuator and said switch member, and thermal bending of said bimetallic latch releasing said switch member to permit opening movement of said switch member.

5. In a circuit breaker comprising stationary and movable contacts, a movable contact bar pivoted at an end and having the movable contact at the other end, an actuating lever having one end pivoted adjacent the pivoted end of said movable contact bar, said contact bar and said actuating lever extending substantialy in opposite directions from the pivoted ends thereof, a thermally responsive trip element mounted on said contact bar at the pivoted end thereof and having a portion disposed in latching engagement with said actuating lever, said thermally responsive trip element and said contact bar extending substantially parallel in opposite directions from said pivoted ends, a spring biasing said contact bar and said actuating lever in opposite directions and biasing said contact bar in opening direction, said thermally responsive trip element deflecting when heated a predetermined amount to release said contact bar from said actuating lever to permit said spring to move said contact bar to open position, and manual means for moving said actuating lever and said contact bar to open and to closed positions.

6. In a circuit breaker comprising stationary and movable contacts, a movable contact bar pivoted at one end and carrying the movable contact at the other end, an actuating lever having one end pivoted adjacent the pivoted end of said contact bar, said contact bar and said actuating lever extending in opposite directions, a thermally responsive trip element mounted on said contact bar at the pivoted end thereof and extending in the opposite direction from said movable contact, said thermally responsive trip element normally releasably engaging said actuating lever, spring means biasing contact bar and said actuating lever in opposite directions and biasing said contact bar in opening direction relative to said actuating lever, thermal bending of said thermally rehaving one end pivoted adjacent the pivoted end by said switch member and the other end free for moving said switch member to open and closed positions, a bimetal element rigidly mounted on said switch member at the pivoted end thereof and releasably engaging said actuator, said bimetal element and said switch member extending generally at right angles to each other, an operating handle movable to an on and to an ofif position, an operating spring compressed between one end of said handle and the free end of said actuator, said operating spring being operable by said handle to cause opening and closing movements of said actuator and said switch member and thermal bending of said bimetal element releasing said switch member to permit opening movement of said switch member free of said actuator.

8. A circuit breaker having a casing of insulating material, relatively movable contacts, a switch member biased open and movable to open and close said contacts, an actuator having one end pivoted and the other end free for moving said switch member to open and close said contacts, a bimetal element rigidly mounted on said switch member and movable edgewise by said actuator to open and close said contacts, thermal 'bending of said bimetal element causing release of said himetal element from said actuator and opening movement of said switch member, an operating handle slidably mounted in said casing and slidable to an open position and to a closed position, the free end of said actuator being guided in said slidable handle, and an operating spring compressed between said slidable handle and the free end of said actuator and operable by said slidable handle to move said actuator to said open and closed positions.

9. A circuit breaker havig relatively movable contacts, a contact arm biased open, said contact arm being pivoted at one end and movable to open and close said contacts, a bimetal element mounted on the pivoted end of said contact arm and movable therewith, an actuator having one end pivotally mounted adjacent the pivoted end of said contact arm releasably engaged by said himetal element and operable to move said contact arm to open and closed positions, thermal bending of said bimetal element causing release of said bimetal element from said actuator and opening movement of said contact arm free of said actuator, stationary electromagnetic tripping means, and said bimetal element only when said contact arm is moved to said closed position being moved to a position where it is engageable by said stationary electromagnetic tripping means to release said bimetal element from said actuator.

10. A circuit breaker having relatively movable contacts, a contact arm biased open and movable to open and close said contacts, a bimetal element movable with said contact arm, an actuator releasably engaged by said bimetal element and operable to move said contact arm to open and closed positions, thermal bending of said bimetal element causing release of said bimetal element from said actuator to permit opening movement of said contact arm, stationary electromagnetic tripping means having a bell crank one arm of which is engageable with said bimetal and the other arm of said bell crank forms an armature, and said bimetal element only when moved by said actuator to said closed position being moved to a position where it is engageable by said one arm of said bell crank to efiect release of said bimetal element from said actuator.

References Cited in the file of this patent UNITED STATES PATENTS Locher May 22, 1956

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