US3480900A

US3480900A - Circuit breaker with improved conducting path and trip means

Info

Publication number: US3480900A
Application number: US698848A
Authority: US
Inventors: Francis L Gelzbeiser; Gerald J Deangelo
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1968-01-18
Filing date: 1968-01-18
Publication date: 1969-11-25
Anticipated expiration: 1986-11-25
Also published as: FR2000386A1; JPS48464B1; GB1211522A

Description

Nov. z5, 1969 F, L, GEM-HEBER Em. 3,480,900

CIRCUIT BREAKER WITH IMPROVED CONDUCTING PATH AND TRIP MEANS Filed Jan. 18, 1968 l C5 Sheets-Sheet 1 1:1 0 l@ l@ m g Q Q ml m E :5 .5| 99| 23 E 0 1--1 V 1 lo EL l (D h 7|./

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1| 2R, E l l m I m o m m E l PJ r i i U I D Q Q i J I f l ||||l g *d L I Q I S Y il WITNESSESI INVENTORS Francis LGelzhiser und Gerold J. DeAngelo.

No 25 1959 F. L. GELzHEIsER ET AL 3,480,900

CIRCUIT BREAKER WITH IMPROVED CONDUCTING PATH AND TRIP MEANS NV 25 1969. F. L.. GELzHElsER ET AL 3,480,900

CIRCUIT BREAKER WITH IMPROVED CONDUCTING PATH AND TRIP MEANS Filed Jan. 18, 1968 3 Sheets-Sheet :5

FIGS.

United States Patent O 3,480,900 CIRCUIT BREAKER WITH IMPROVED CONDUCT- ING PATH AND TRIP MEANS Francis L. Gelzheiser, Fairield, and Gerald J. DeAngelo,

Monroe, Conn., assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Jan. 18, 1968, Ser. No. 698,848 Int. Cl. H01h 71 /16 U.S. Cl. 337-75 9 Claims ABSTRACT OF 'TI-IE DISCLOSURE A circuit breaker is provided with an improved compact arrangement of parts and with an improved trip device for tripping the circuit breaker upon the occurrence of overload current conditions.

CROSS-REFERENCES TO RELATED APPLICATIONS Certain features of the herein disclosed circuit breaker are disclosed in the copending applications Ser. No. 698,891, tiled Jan. 18, 1968 and Ser. No. 698,809, led Jan. 18, 1968, which applications are filed concurrently herewith.

BACKGROUND OF THE INVENTION This invention relates to circuit breakers of the type comprising a bimetal actuator for tripping the circuit breaker with a time delay upon the occurrence of certain overload current conditions. A compact construction and arrangement of parts is provided whereby the overall dimensions of the circuit breaker are kept reduced. Improved means is provided for preventing the loss of calibration of the trip device when forces are applied to the terminal connector. A `dual-latch trip is operated to release a trip member in order to trip the circuit breaker.

SUMMARY OF THE INVENTION An improved circuit breaker comprises a rigid conductor that extends lengthwise in the base and that supports a tripping bimetal that is supported at one end to the conductor and that extends lengthwise along the conductor. The bimetal and the rigid conductor comprise parallel current paths in the vicinity of the trip device. The conductor and bimetal are supported in the breaker on the breaker base over a line-terminal cavity and under a trip device to provide a compact arrangement. The trip device comprises a dual-latch trip supported on spaced side plates. The rigid conductor extends into a cavity at the end of the circuit breaker where the conductor is connected to a conducting line Iby means of a pressure-type terminal. The rigid conductor is xedly supported on the housing base by means of the securing means that secures the housing cover to the housing base sandwiching the rigid conductor between the cover and the base to prevent loss of calibration when forces are applied to the pressure-type connector.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a top plan View `of a two-pole circuit breaker constructed in accordance with principles of this` invention;

FIG. 2 is a sectional view taken generally along the line II-II of FIG. 1 showing the circuit breaker in the closed position;

FIG. 3 is a view similar to FIG. 2, with parts broken away, and with the breaker in the off position;

FIG. 4 is a View similar to FIG. 3 with the breaker in the tripped position;

3,480,900 Patented Nov. 25, 1969 ICC DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, there is shown therein a circuit breaker 5 comprising an insulating housing 7 and a circuit-breaker structure 9 supported on the housing 7.

The insulating housing 7 is a two-part housing comprising a base 11, having a generally planar bottom, and a cover 13 secured to the base 11 by means of three rivets 15. The base 11, at one end thereof, 'comprises insulating barriers 17 forming two adjacent cavities. The cavities are open at the top and open at the one end of the housing for receiving two clamp-type terminal connectors -19 that are used to connect conducting lines to the two pole units. The terminal connectors 19 are more specifically described in the copending patent application of Kenneth R. Coley, Ser. No. 698,809, led Ian. 18, 1968. The base 11 and cover 13 cooperate to form two adjacent compartments 21 for housing the circuit breaker parts of the two pole units.

Each of the circuit-breaker structures 9 comprises an operating mecthanism 23, trip structure 25 and trip device 27. A separate circuit-breaker structure 9 is supported in each of the compartments 21.

Since the parts of the two pole units of the circuit breaker are identical, only the pole unit seen in FIGS. 2-4 will be specifically described.

Referring to FIG. 2, the operating mechanism 23 comprises a stationary contact 29 and a movable contact 31. The stationary contact 29 is fxedly secured to a rigid conductor 33 that extends toward the load end into a cavity 35, formed in the base 11, where the conductor 33 is connected to or is part of a clip-on type terminal connector 37 that is supported in the cavity 35. The cavity 35 is open at the bottom of the ibase 11 for receiving a stab conductor that would protrude into the cavity 35 to be engaged by the clip-on type terminal connector 37. The movable contact 31 is ixedly secured to an elongated contact arm 39. The contact arm 39 is provided with aslot 41 therein for receiving a supporting pin 43. A torsion spring 45 biases the contact arm 39 toward the open position seen in FIG. 3 wherein the pin 43 is at the lower part of the slot 41. A toggle 47 connects the contact arm 43 with an angle-link 49 of a trip structure 51. The toggle 47 comprises a lower toggle link 53 and an upper toggle link 55. The lower toggle link 53 is pivotally connected to the contact arm 39 by means of a pin 57 and the upper toggle link 55 is pivotally connected to one leg of the anglelink 49 by means of a pin 59. The

toggle links

53 and 55 are pivotally connected by means of a knee pivot pin 61. 'Ihe angle-link 49 comprises two legs that are angularly spaced and movable as a unit. The angle-link 49 is mounted on a ixed pivot 63 that is supported between a pair of rigid side plates that are supported in the associated compartment. lOniy one of the side plates 65 is seen in FIG. 2, and `both of the side plates are seen in FIG. 6. As can be seen in FIG. 6, the

links

53, 47 and 49 are twin links in that each of these links comprises `a pair of spaced connected link members. As is lbest seen in FIG. 6, the other leg of the angle-link 49 is provided with a slot 65 therein for receiving a pin 67 that also extends through an opening 69 in a releasable cradle member or trip member 71. The pin 67 moves in the slot 65 and opening 69 permitting relative movement between the angle-link 49 and the trip member 71 during tripping and resetting operations. The trip member 71 is pivotally supported, intermediate the ends thereof, on and between the side plates 65, by means of a pin 73. The trip member 71 is maintained in the latched position seen in FIG. 2 by means of the trip device 27.

The trip device 27 comprises a latch member 75 that is pivotally supported, intermediate the ends thereof, between the side plates 65 on a pin 77. The latch member 75 is biased in an unlatching (counterclockwise FIG. 2) direction by means of a torsion spring 79. The upper end of the latch 75 engages the trip member 71 to latch the trip member 71 in the position seen in FIG. 2. The lower end of the latch member 75 is latched by means of a member 81 that is pivotally supported intermediate the ends thereof on a pin 83 that is supported between the side plates `65. The latch member 81 is biased in a latching (clockwise FIG. 2) direction about the pin 83 by means of a torsion spring 85. A Calibrating screw 87 is threadedly supported on one end of the latch member 81.

In the closed position of the circuit breaker 5, a circuit extends from the plug-in line terminal 37 through the conductor 33, stationary contact 29, movable contact 31, contact arm 39, parallel

flexible conductors

89 and 91,

parallel conducting paths

93 and 95, through the lefthand (FIG. 2) part of the conductor 93 to a conducting line that may be connected to the conductor 93 by means of the clamp-type terminal connector 19. The conductor 93 is a rigid conductor that is fixedly secured in the housing 7. As can be seen in FIG. '2, the rigid conductor 93 rests on a generally flat part of the base above the cavity 35. A ilexible pad 99 is placed over the conductor 93, and when the housing cover 13 is tightly riveted down against the base 11 the pad 99 and rigid conductor 93 are sandwiched between the cover 13 and base 11 so that the clamping force of the rivets (FIGS. 1 and 6) operates to xedly secure the rigid conductor 93 within the housing. The main conducting path between the contact arm 39 and clamp-type terminal 19 is through the rigid conductor 93. A parallel conducting path is provided through the flexible conductor 91 and bimetal 95. As can be seen in FIG. 2, the bimetal 95 is supported at the left end thereof on the rigid conductor 93, and the free end of the bimetal 95 is free to ex in an upward (FIG. 2) direction to trip the circuit breaker.

Referring to FIG. 2, it will be noted that the housing is provided with an opening in the front thereof. A handle part 105 of an insulating operating member 107 protrudes through the opening to permit manual operation of the circuit breaker. The insulating operating member 107 is pivotally supported on the side plates 65 by means of a pin 109. A torsion spring 113 biases the operating member 107 in a clockwise (FIG. 2) direction. A link member 115 is pivotally connected, at one end thereof, to the knee 61 of the toggle 47. The link 115 is pivotally connected at the other end thereof to the lower end of the operating member 107 by means of a pin 117. The pin 117 moves in an opening 119 in the trip member 71.

The circuit breaker is shown in FIG. 2 in the closed position with a generally L-shaped insulating member 121 insulating the rigid conductor 33 from the conductors that are positioned above the insulating member 121. A coil compression spring 123 is positioned under the rigid conductor 33 to bias the conductor 33 upward to provide Contact pressure between the

contacts

29, 31 in the closed position of the contacts. The housing base is provided with an insulating projection 125 that extends into an opening in the conductor 33 to prevent substantial lateral movement of the conductor 33. Upward movement of the conductor 33 is limited by an insulating member 200 that is held down by the plates 65 that are in turn held down by the cover 13. An arc-extinguishing structure 127 is provided for extinguishing arcs drawn between the contacts during opening operations.

The circuit breaker is shown in the closed position in FIG. 2. When it is desired to manually operate the circuit breaker to the open position, the operating member 107 is pivoted from the on position seen in FIG. 2 to the oit position seen in FIG. 3. During this movement, the operating member 107 operates through the link 115 to move the knee 61 of the toggle 47 to the left whereupon the erected toggle 47 collapses moving the contact arm 39, toggle 47, link and operating member 107 to the full open position seen in FIG. 3. The opening operation is effected by the force of the worker manually moving the operating member 107 which force is aided by the forces of the

springs

123, 45 and 113. During the opening operation, as the toggle 47 starts to collapse the spring 45 first moves the Contact arm 39 to the position where the pin 43 is at the lower point of the slot 41 during which movement the heel part of the movable contact 31 first separates from the stationary contact 29, and when the pin 43 engages the contact arm at the bottom of the slot 41 the nal movement of the contact arm 39 is counterclockwise about the pin 43 during `which movement the toe portion of the movable contact 31 separates from the stationary contact 29 and during which movement the contact arm 39 pivots about the pin 43 to the fully open position seen in FIG. 3.

When it is desired to manually operate the circuit breaker to the closed position, the operating member 107 is manually operated from the oit position (FIG. 3) to the on position (FIG. 2). During this movement, the link 115 is driven by the operating member 107 to operate the toggle 47 from the collapsed to the erected position. During the initial part of this movement, the contact arm 39 pivots about the pin 43 until the toe of the contact 31 engages the stationary Contact 29 whereupon further closing movement of the toggle 47 operates to move the contact arm 39 to the `fully closed position, wherein both the toe and heel of the contact 31 engage the stationary contact 29, during which movement the left (FIG. 2) end of the contact arm 39 is moved downward, as the slot 41 moves relative to the stationary pivot pin 43, to the fully closed position.

During the manual opening and closing operations of the circuit breaker, the angle-link 51 is stationary to maintain the pivot 59 of the upper toggle link 55 fixed.

The circuit breaker is tripped open by operation of the trip device 27. In addition to the bimetal 95, the trip device 27 comprises a U-shaped magnetic member 127 supported with the bight portion thereof in a cavity 129 in the base 11 and with the opposite legs thereof extending upward on opposite sides of the rigid conductor 93 and on opposite sides of the bimetal 95. The latch member 81 is magnetic, and the left-hand (FIG. 2) end of this member is positioned above the opposite legs of the member 127 whereby the member 81 functions as an armature of an electromagnetic trip structure. An alternative construction would be to -make the latch member 81 nonmagnetic and to secure a magnetic member to the member 81 above the member 127.

Upon the occurrence of an overload above a first predetermined value and below a second predetermined Value, the bimetal 95, which is heated by the heat generated by the current ilow therein and which is also heated by the heat generated in the rigid conductor 93, flexes with the free end (on the right) moving upward to engage the Calibrating screw 87 to move the latch member 81 in a counterclockwise direction to release the latch member 75. Upon release of the latch mem'ber 75 the trip member 71 is released and the contact arm 39 is free to move to the open position under the bias of the spring 45. Although the main tripping force is exerted by the spring y45, the contact pressure spring 123 provides additional force during the initial movement, and the relatively weak spring 113 also aids in providing an opening force. The blow-off force generated by the arc also aids the tripping movement. The contact arm 39 moves from the position shown in FIG. 2 to the tripped position shown in FIG. 4 with the trip member 71 moving clockwise and with the angle-link 51 moving counterclockwise to permit the upper pivot 59 of the toggle 47 to move to release the toggle 47 which collapses to the tripped position seen in FIG. 4. During the tripping operation, the spring 113 operates to move the operating member 107 to a tripped position (FIG. 4) intermediate the on and olf positions. The operating member 107 is stopped in the tripped position by engagement of the pin 117 with an edge of the trip member 71 in the slot 119. When it is desired to reset the circuit breaker for manual operation, the operating member 107 is moved from the tripped position seen in FIG. 4 to a position slightly past the full oli position seen in FIG. 3. During this movement, the pin 117 engages the trip member 71 in the slot 119 to rotate the trip member 71 in a counterclockwise direction. Near the end of this movement of the operating member 107, the end of the trip member 71 engages the latch member 75 moving the latch member clockwise to the latching position and when the latch member 75 reaches the latching position the spring 85 biases the latch member 81 to the latching position t0 latch the latch member 75 whereby upon release of the operating member 107 the circuit breaker will be latched in the position seen in FIG. 3. When the trip member 71 is in the latched position the angle-link 51 is held stationary so that the upper pivot 59 of the toggle 47 is iixed whereby the circuit breaker may be manually operated between the on and off positions in the same manner hereinbefore described. The slot-and-pin connection between the angle-link 51 and trip member 71 prevents movement of the angle-link 51 when the trip member is latched in a stationary position and permits the relative movement between these parts during the tripping and resetting operations. The angle-link 51 enables a tripping operation of the trip member 71 with the trip member 71 not moving to a position substantially higher within the circuit 'breaker housing than the original position of the trip member 71 so that the heightwise dimension of the circuit breaker housing can be kept compact.

Upon the occurrence of an overload above the second predetermined value, magnetic flux generated in the

members

127, 81 by means of the current owing through the

members

93, 95 causes attraction of the armature 81 to the yoke 127 whereupon the armature 81 moves to the tripped position instantaneously without the time delay of the thermal tripping operation. Upon movement of the latch member 81 to the tripped position the circuit breaker is tripped in the same manner as was hereinbefore described with regard to the thermal tripping operation. The circuit breaker is thereafter reset in the same manner as was hereinbefore described with regard to the resetting operation following the thermal tripping operation.

As was previously set forth, the circuit breaker 5 is a two pole circuit breaker with each of the poles constructed as shown in FIGS. 2-4 and 6. A handle tie member 135 (FIG. l) connects the handles of the two pole units together for simultaneous manual operation. In order to provide that both of the pole units will trip upon the tripping of either of the pole units, a separate member 137 (FIG. 2) is pivotally mounted between the side plates 65 of each of the poles. Each of the members 137 is pivotally supported on a pin 139. The members 137 in the two pole units are operatively connected for simultaneous pivotal movement about the same axis. Upon the occurrence of a tripping operation in either pole unit, the associated latch 75 will engage the associated member 137 to cam the member 137 in a counterclockwise (FIG. 2) direction whereupon both of the members 137 will simultaneously move counterclockwise so that the member 137 in the adjacent pole unit will engage that armature 81 to move the armature 81 in the adjacent pole unit to the tripped position. When the circuit breaker is reset, the armatures 81 engage the members 137 to move the members 137 to the position shown in FIG. 2.

As is shown in FIG. 4, the operating member 107 is moved to an intermediate position during tripping operations to provide a visual indication that the circuit 'breaker is tripped. Thus, it is necessary to reset the circuit breaker in the manner hereinbefore described in order to manually operate the breaker aft-er each tripping operation. If it is desired to provide an automatic-reset circuit breaker, the spring 113 is strengthened to provide enough drive during a tripping operation to force the operating member 107 to the reset position. With the strengthened spring mounted in the breaker, the operating member 107 will be automatically moved to the reset position during tripping operations. Thus, after tripping operations, the breaker will be automatically reset and a worker will be able to manually operate the breaker without manually resetting the breaker.

From the foregoing, it can be understood that there is provided by this invention an improved circuit breaker of compact construction. The circuit breaker comprises a conducting path that extends from one terminal connector lengthwise in one direction through the breaker to the contacts and then back toward the one terminal to a clipon type terminal connector that is positioned in a cavity open at the bottom of the breaker. A rigid conductor which extends from the one terminal within the breaker 1s supported lengthwise on the base over the cavity. An elongated bimetal is connected at one end to the rigid conductor and extends lengthwise along the conductor over the cavity and under a dual-latch trip device. The bimetal and rigid conductor form parallel conducting paths. When the bimetal is heated by certain Overload currents, the bimetal flexes upwardly to eirect release of a dual-latch structure to thereby trip the breaker. The latch members of the dual-latch trip device are supported between common side plates, and the rigid conductor is xedly supported on the base for stable calibration. The rigid conductor extends through opening means in the housing to a cavity where the conductor is connected to a conducting line by means of a solderless terminal pressure connector. The housing securing means, which secures the housing cover to the housing base, sandwiches the rigid conductor and a exible pad between the cover and base to xedly secure the rigid conductor within the houslng so that the forces exerted on the solderless termlnal connector will not destroy the ycalibration of the trip device.

We claim as our invention:

1.. A circuit breaker comprising an insulating housing, a clrcuit-breaker structure supported in said housing, said circuit-breaker structure comprising a pair of contacts, an operating mechanism operable to open and close said contacts, trip means operating automatically upon the occurrence of overload current conditions above a predetermined value to effect automatic opening of said contacts, conducting means comprising a rigid conductor in electr1cal series with said contacts, an externally accessible terminal connector supported on said housing for connecting a conducting line to said rigid conductor, said housing comprising an insulating base and an insulating cover, securing means drawing said cover and said base together to secure said cover to said base and sandwiching said rigid conductor between said cover and said base to iixedly support said rigid conductor on said base, and said trlp means comprising a bimetal tripping member xedly secured to said rigid conductor which bimetal tripping member exes upon the occurrence of certain overload current conditions to effect automatic opening of said contacts.

2. A circuit breaker according to claim 1, and a flexible member sandwiched between at least one of said housing parts and said rigid conductor.

3. A circuit breaker according to claim 1, said rigid conductor engaging said terminal connector to iixedly position said terminal connector on said housing.

4. A circuit breaker according to claim 2, a pair of spaced parallel supporting plates in said housing, said circuit-breaker structurecomprising an operating mech# anism supported on said parallel Asupporting plates, said circuit breaker structure comprising a releasable member, a rst latch latching said releasable member, means pivotally supporting said first latch on said side plates, a second latch latching said first latch, means pivotally supporting said second latch on said side plates, and upon the occurrence of certain overload current conditions said bimetal moving said second latch to release said first latch to thereby release said releasable member whereupon said releasable member moves to effect automatic opening of said contacts.

5. A circuit breaker comprising an insulating housing having an opening at the front thereof, a first terminal connector at one end of said housing, a pair of contacts in proximity to the other end of said housing, an operating mechanism comprising a handle extending from said opening and being operable to open and close said contacts, said housing having a cavity therein open at the bottom thereof which cavity is positioned between said iirst terminal connector and said operating mechanism relative to the length of said housing, a second terminal connector supported in said cavity, conducting means connecting said first terminal connector said contacts and said second terminal connector in electrical series, said conducting means comprising a rigid conductor extending lengthwise in said housing over said cavity, a trip device comprising an elongated bimetal supported at one end thereof on said rigid conductor and extending lengthwise along said rigid conductor, and upon the occurrence of certain overload current conditions said bimetal flexing and moving to effect automatic opening of said contacts.

6. A circuit breaker according to claim 5, a trip device supported in said housing above said bimetal, said trip device being positioned between said operating mechanisms and said first terminal connector relative to the length of said housing, said operating mechanism `comprising a releasable member, said trip device comprising latch means latching said releasable member and operable by said movement of said bimetal to effect release of said releasable member.

7. A circuit breaker according to claim 5, said rigid conductor and said bimetal being connected to provide parallel current paths at the vicinity of said bimetal,

8. A circuit breaker according to claim 7, said operating mechanism comprising a releasable member releasable to effect automatic opening of said contacts, said trip device comprising a first latch latching said releasable member and a second latch latching said first latch, said bimetal upon said movement thereof moving said second latch to thereby release said first latch to release said releasable member to effect automatic opening of said contacts, a stationary magneticmember energized by the current in said rigid conductor and in said bimetal, and said second latch comprising an armature portion movable toward said magnetic member upon the occurrence of certain severe overload current conditions to release said first latch to thereby release said releasable member.

9. A circuit breaker according to claim 8, a pair of side plates supported in said housing, said releasable member said first latch and said second latch being supported on and between said side plates.

References Cited UNITED STATES PATENTS 2,102,545 12/1937 Rowe 337-110 2,573,306 10/1951 Casey 337-75 BERNARD A. GILHEANY, Primary Examiner R. L. COI-IRS, Assistant Examiner U.S. Cl. X.R. 337-45, 112