US3707612A

US3707612A - Circuit interrupter with improved molded insulating housing formed with vent passage means

Info

Publication number: US3707612A
Application number: US153198A
Authority: US
Inventors: Nick Yorgin; John G Salvati
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1970-02-16
Filing date: 1971-06-15
Publication date: 1972-12-26
Anticipated expiration: 1989-12-26
Also published as: AU8055175A; US3632939A; GB1300204A; GB1300203A; AU482990B2

Abstract

A circuit interrupter comprises a molded insulating housing molded to form improved vent passage means for venting arc gases from the housing.

Description

United States Patent Yorgin et al. [4 1 Dec. 26, 1972 54 CIRCUIT INTERRUPTER WITH [581 mu of Search ..2o0/144 R, 168 R IMPROVED MOLDED INSULATING HOUSING FORMED WITH VENT [56] References Cited PASSAGE MEANS i UNITED STATES PATENTS [72] Inventors: Nick Yorg n, Ambridge; John G.

3,489,872 l/l970 Casey ..200/l44 R Beaver Falls bah 3,564,176 2/1971 Fechant... ..200/144 R [73] Assignee: Westinghouse Electric Corporation, 3,422,235 1/1969 Camp ..200/ 144 R X Pittsburgh, Pa. 3,349,204 l0/l967 Fair ..200/l44 R X Filed? June 1971 Primary Examiner-H. 0. Jones [21] Appl, No.1 153,198 Attorney-A. T. Stratt0n et al.

Related US. Application Data 57 ABSTRACT Division Of 114 197, l- A circuit interrupter comprises a molded insulating housing molded to form improved vent passage means 1 for venting arc gases from the housing. [52] U.S. Cl. ..200/l68 R, 200/144 R [51] Int. Cl. ..H01h 9/30, HOlh 33/76 4-Claim s, 8 Drawing Figures H J 101 T PATENT'ED DEC 26 I972 3,707,612

sum 1 0F 3 FL. L

PATENTED DEC 2 s 1972

sum

3 or 3 FIG. 5

CIRCUIT INTERRUPTER WITH IMPROVED MOLDED INSULATINGHOUSING FORMED WITH VENT PASSAGE MEANS CROSS REFERENCE TO RELATED APPLICATION This application is a division of the application of Nick Yorgin et al. Ser. No. ll,452 filed Feb..l6, 1970 now US. Pat. No. 3,632,939.

BACKGROUND OF THE INVENTION l. Field of The Invention Circuit interrupters of the type comprising a molded insulating housing and a circuit interruptor mechanism supported in the molded insulating housing.

2. Description of The Prior Art his old in the circuit interruptor art to provide a molded insulating housing for the interruptor with cavities at one end for receiving the terminals of the interruptor and with wire screens, or insulating barriers having openings therein, supported on the insulating housing for venting gases from the housing into the area of the cavities. This invention is an improvement over the prior art in that the insulating housing is molded to form vent passages that lead into the terminal cavities with the vent passages being directed toward the sidewalls of the terminal cavities to make it more difficult for an elongated wire or other foreign member to be moved into the housing through the vent passages.

SUMMARY. OF THE INVENTION An improved circuit interruptor comprises a molded insulating housing and a circuit interrupter mechanism supported in the insulating housing. The insulating housing comprises molded projection means extending from an end wall to form a plurality of cavities at an end of the interrupter for receiving. solderless terminal connectors. The molded projection means forms generally planar spaced parallel surfaces that extend from the end wall along parallel planes which parallel surfaces serve as side walls of the cavities. The end wall of the insulating housing has a thickness dimension. The end wall is molded to form a plurality of vent passages through the thickness thereof for each pole unit of the interrupter. At each pole unit the vent passages extend from the inner surface of the end wall to the other surface of the end wall diverging toward the side walls of the associated cavity to thereby provide vent passages that do not readily receive elongated wires or other foreign members that could be moved into the housing through the vent passages.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a top plan view ofa circuit interrupter constructed in accordance with the principles of this invention; i

FIG. 2 is a side sectional view taken generally along the line II-II of FIG. 1;

FIG. 3 is a partial sectional view taken generally BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, there is shown, in FIGS. 1 and 2, a multi-pole molded-case or insulating housing type circuit interrupter 3. The circuit interrupter 3 is a circuit breaker of the type that is more specifically described in the copending application of Nick Yorgin et al. US. Pat. No. 3,460,075 issued Aug. 5, 1969. Thus, only a brief description of the circuit interrupter is provided herein. The circuit interrupter comprises an insulating housing 5 and a circuit interrupter mechanism 7 supported in the housing 5. The housing 5 comprises a molded insulating base 9 and a molded insulated cover 11 secured to the base 9 to enclose the circuit interrupter mechanism that is mounted on the base 9. The insulating housing 5 will be hereinafter more specifically described. 7 v

The circuit interrupter mechanism 7 comprises an operating mechanism 13, a latch mechanism 15 and a trip device 17'.

A stationary contact 19, a movable contact 2l and an arc-extinguishing unit 23 are provided for each pole of the circuit interrupter. The movable contact 21 is mounted on a movable contact arm 25 that is connected to a switch arm 26 that is secured to an insulating common tie bar 27. The tie bar 27 is supported for pivotal movement about theelongated axis thereof. A toggle, comprising a toggle link 29 and a toggle link 31, is pivotally connected at one end thereof to the movable switch arm' 26 of the center pole unit and at the other end thereof to a latched trip member 33 that is pivotally supported on a pin 35. that is mounted between a pair of supporting plates 37. An operating tension spring 39 is connected at one end thereof to the knee pivot 41 of the toggle and at the other end thereof to the bight portion of an inverted generally U-shaped operating member 43. A handle 45 extends from the lever 43 through an opening in the front of the housing cover 11 to permit manual operation of the interrupter. The releasable trip member 33 is latched at one end thereof by means of a roller latch member 47 that is in turn latched by an elongated insulated trip bar 49 that is mounted for pivotal movement about the elongated axis thereof. The operating lever 43 is an inverted U- shaped lever that is mounted at the ends of the legs thereof in U-shaped notches in the supporting plates 37.

The circuit interrupter is manually operated by operation of the handle 45 from the open position seen in FIG. 2 in a clockwise direction to the closed position during which movement the line of action of the spring 39 is moved to the right to erect the toggle 29, 31 to pivot the movable switch arm 26 in a clockwise direction to the closed position.

The interrupter is manually opened by reverse movement of the handle 45 in a counterclockwise direction to the open position during which movement the line of action of the spring 39 is moved to the left to collapse the toggle 29, 31 to thereby move the switch arm 26 of the center pole unit to the open position seen in FIG. 2.

Since all three of the switch arms 26 for the three pole units of the three-pole circuit interrupter are fixed to the common tie bar 27, operation of the center-pole tripping operation in the same manner as was hereinbe- I fore described following a time delay thermal tripping switch arm 26 simultaneously operates all three of the ble conductor 61, a conducting member 63,-to a terminal connector 65.

Upon the occurrence of an overload above a first predetermined value, the bimetal 51 becomes heated and flexes to the right (FIG. 2) whereupon the screw 53 engages the trip bar 49 to rotate the trip bar 49 in a operation.

The insulating base 9 (FIGS. 2 and 5) is a molded insulating member molded with integral barriers 87 that cooperate with barriers'89 (FIGS. 2, 6 and 7),'that are molded integral with the insulating cover 11, to separate the housing 5 into three adjacent pole-unit compartments. The

barriers

87, 89 are formed to provide parts that overlap in order to prevent the passage of gases between adjacent pole units. The base and cover, however, engage each other at a generally planar engagement as shown by the line 90 (FIGS. 2

counterclockwise direction whereupon the trip bar 49 releases the latch 47. Upon release of the latch 47, the

spring 39, operating through the toggle 29, 31, pivots the trip member 33 in a clockwise direction with the latch 47 moving in a clockwise direction about its pivot 71. This movement changes the line of action of the spring 39 whereupon the spring collapses the toggle 29, 31 to move the movable switch arms 26 to the open position. During the tripping operation, the spring 39 moves the handle 45 to a position intermediate the ON and OFF positions to provide a visual indication that the interrupter has tripped. Following a tripping operation, the interrupter is reset by movement of the handle 45 in a counterclockwise direction to a position slightly past the full OFF position. During this movement, a projection 73 on the operating member 43 engages a shoulder on the trip member 33 to rotate the trip member 33 in a counterclockwise direction during which movement the trip member 33 engages the latch 47 to move the latch to the latching position, and a spring 77 moves the trip. bar 49 to the latching position so that upon release of the handle 45 the interrupter will be latched in the reset position seen in FIG. 2. Thereafter, the circuit interrupter can be manually operated in the same manner as was hereinbefore described.

The circuit interrupter is magnetically tripped by operation of an electromagnet that comprises a stationary magnetic member 81 and a movable magnetic armature 83 that is supported for pivotal movement by means of a pair of pivot arm supports 85. The current in the bimetal 51 energizes the

magnetic members

81, 83. Upon the occurrence of the severe overload above a second predetermined value the armature 83 is attracted to the magnetic member 81 whereupon a part of the armature above the pivot support 85 thereof engages the trip bar 49 to rotate the trip bar 49 in a counterclockwise direction to effect an instantaneous magnetic tripping operation. A shunt conductor 86 on the armature 83 is utilized to shunt current through the stationary magnetic member 81 to the conductor 63 to thereby shunt current past the bimetal upon the occurrence of a magnetic tripping operation to protect the bimetal against excessive heating. The circuit interruptcr is reset following an instantaneous magnetic and 4). As can be understood with reference to FIG. 2, there is 5 single operating mechanism 13 and single latch mechanism 17 in the center pole-unit compartment. The circuit in each pole-unit is the same as that hereinbefore described with regard to the center poleunit, and there is a separate trip device 17 in each pole unit for operating the common trip bar 49 to trip the interrupter upon the occurrence of an overload in any of the pole units. The insulating cover 11 islformed with four openings 91 the'rethrough which align with tapped openings 93 in the insulating base 9 to receive four screws 95 (FIG. 3) which serve to secure thecover 9 to the base 11. The insulating base 9 is formed with four openings 97 therethrough which align with four openings 99 in the insulating cover 11 for receiving mounting bolts that extend through the

openings

97, 99 in the base and cover to secure the circuit interrupter 3 to a panel-at the installation. It is necessary to insulate the mounting bolts from the internal live parts of the circuit-interrupter at the area where the cover 11 engages the base 9. For example, when there is a circuit interruption, pressure generated by the arcs can blow the cover and base slightly apart and the ionized gases could cause a flashover from one of the poles to ground through a mounting bolt that would be grounded at the installation. In order to adequately insulate the mounting bolts from internal live parts of the circuit interrupter, the cover is molded with four insulating tube portions 101 that are molded integral, with the cover, which tube portions 101 nest within larger diameter opening portions 103 of the openings 97 in the insulating base 9. The tube portions 101, nesting within the openings 103 of the base 9, extend through the plane of the generally planar engagement 90 between the base and cover to insulate the mounting bolts from the internal live parts of the circuit interrupter at the area where the insulating cover 11 engages the insulating base 9.

As can be seen in FIG. 5, the insulating base 9 is molded with slot means 105 therein at each pole unit compartment at one end of the base 9. The insulating cover is molded with slot means 107 therein at each pole unit compartment, which slot means 107 aligns with the associated slot means 105 of the base 9. During assembly of the circuit interrupter, an insulating member 113 (FIG. 2) is positioned in the associated slot means 105, 107 of each pole unit to close off endwall openings in the insulating housing 5 at the arcextinguishing end of the insulating housing 5. The base 9 is formed with slot means 117 therein at each pole unit compartment thereof at the opposite end of the base 9. During assembly of the circuit interrupter, an insulating member 1 19 (FIG. 2) is positioned in the slot means 117 before the cover 11 is mounted on the base. The top of the barriers 119 engage the bottom surface of the cover end wall 123 when the cover is mounted on the base. As can be seen in FIG. 6, the insulating cover 11 is molded to provide and end wall part 123 at the one end of the housing with projections 125 extending from the end wall 123 to cooperate with similar projections 126 on the base 9 to provide three cavities 127 for the three terminal connectors 65 at the one end of the interrupter. The

projections

125, 126 insulate the adjacent externally accessible terminal connectors 65 from each other. As can be seen in FIG. 6, the end wall portion 123 of the cover 11 comprises an internal generally planar wall surface 129 and an external generally planar wall surface 131 at opposite sides of the thickness of the end wall portion 123. The projections 125 provide side wall surfaces 133 at each cavity 127 which side wall surfaces 133 are generally parallel to each other and generally normal to the wall surfaces 129, 131 of the end wall portion 123. The insulating cover 11 is molded with two vent passages 137 at each pole unit thereof which vent passages 137 diverge from the internal wall surface 129 through the thickness of the end wall portion 123 to the external wall surface 131 in directions toward the side walls 133.

The ventpassages 137 in each pole unit vent arc gases out of the associated pole unit. As can be seen and understood with reference to FIGS. 6 and 8, with the vent passages 137 diverging outward toward the cavity sidewall surfaces 133, a wire, for example, cannot easily be moved from the external end of the housing into the internal compartment of the housing through the vent passages.

By molding the vent passages and insulating tubes integral with the housing, additional parts are eliminated,

inventory control is facilitated and time is saved during assembly thereby providing a cost saving in the manufacture of the circuit interrupter. Moreover, there is a more reliable fitting of parts and reliability control is enhanced since there is less chance for human error during assembly of the circuit interrupter.

We claim as out invention:

1. A circuit interrupter comprising a molded insulating housing, a circuit-interrupter mechanism supported in said insulating housing, said circuit-interrupter mechanism comprising a pair of cooperable contacts operable to open and close an electric circuit, said insulating housing comprising a molded generally planar end wall at one end thereof and molded projection means extending from said end wall to form a cavity at said one end, said molded projection means comprising generally planar spaced generally parallelsurfaces that extend from said end wall along generally parallel planes that are generally normal to the plane of said end wall which generally parallel'surfaces serve as cavity side wall means providing side walls of said cavity, said end wall having a thickness dimension, and said end wall being molded to form a vent passage through the thickness thereof which vent passage extends from the inner surface of said end wall to the outer surface of said end wall toward one of said side walls of said cavi- 2. A circuit interrupter according to claim 1, and said end wall being molded to form a plurality of vent passages throu h the thickness thereof which vent passages exten from the inner surface of said end wall to the outer surface of said end wall toward said side wall means.

' 3. A circuit interrupter according to claim 2, and said vent passages comprising a pair of vent passages through the thickness of said end wall which vent passages diverge from the inner surface of said end wall to the outer surface of said end wall toward said side walls of said cavity.

4. A circuit interrupter according to claim 3, said insulating housing comprising a back base housing part with said circuit-interrupter mechanism supported thereon and a front cover housing part engaging said base housing part along a generally plane engagement between the back and the front of said insulating housing, and said pair of vent passages being formed in said front cover housing part.

Claims

1. A circuit interrupter comprising a molded insulating housing, a circuit-interrupter mechanism supported in said insulating housing, said circuit-interrupter mechanism comprising a pair of cooperable contacts operable to open and close an electric circuit, said insulating housing comprising a molded generally planar end wall at one end thereof and molded projection means extending from said end wall to form a cavity at said one end, said molded projection means comprising generally planar spaced generally parallel surfaces that extend from said end wall along generally parallel planes that are generally normal to the plane of said end wall which generally parallel surfaces serve as cavity side wall means providing side walls of said cavity, said end wall having a thickness dimension, and said end wall being molded to form a vent passage through the thickness thereof which vent passage extends from the inner surface of said end wall to the outer surface of said end wall toward one of said side walls of said cavity.

2. A circuit interrupter according to claim 1, and said end wall being molded to form a plurality of vent passages through the thickness thereof which vent passages extend from the inner surface of said end wall to the outer surface of said end wall toward said side wall means.

3. A circuit interrupter according to claim 2, and said vent passages comprising a pair of vent passages through the thickness of said end wall which vent passages diverge from the inner surface of said end wall to the outer surface of said end wall toward said side walls of said cavity.