US3293392A - Fuse protected electrical switch - Google Patents

Description

Dec- 20, 1966 J. B. CATALDO ET AL FUSE PROTECTED ELECTRICAL SWITCH Original Filed July 27 1962 4 Sheets-Shea?I l FIG. 2

.Dec- 20, 1966 J. B. cATALDo ET AL 323,392

FUSE PROTECTED ELECTRICAL SWITCH Original Filed July 27, 1962 4 SheetsSheet 2 Dec. 20, 1966 J. B. CATALDO ET AL 3,293,392

FUSE PROTECTED ELECTRICAL SWITCH I Original Filed July 27, 1962 4 Sheets-Sheet 5 Dec. 20, 1966 J. B. CATALDO ET AL 3,293,392

FUSE PROTECTED ELECTRICAL SWITCH Original Filed July 27, 1962 4 Sheets-Sheet 4 United States Patent O n 3,293,392 v, FUSE PROTECTED- ELECTRICAL SWITCH `lohn B.l Cataldo, Bloomfield Hills, Andrew J. Kralik, Detroit, Frank W.,Kussy, Birmingham, and Robert W. Thomas, St. Clair Shores, Mich., assignors to l-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Original application `luly 27, 1962, Ser. No.`212,89t), now Patent No. 3,217,130, dated Nov. 9, 1965. Divided and this application Aug. 2, 1965, Ser. No. 487,951

3 Claims. (Cl. 20G- 114) This invention is a division of application Ser. No. 212,890, now patent 3,217,130, issued on November 9, 1965, to the present inventor and assigned to the assignee o'f the present invention.

This invention relates to circuit interrupters and more particularly to circuit interrupters consisting of a novel vacuum switch and fuse assembly having a parallelogram linkage operating assembly fo'r providing rapid, reliable contact opening and closing operations.

Double break switches of the prior art are comprised of a stationary contact pair having a reciprocating member slideab'ly mounted therebetween. The reciprocating member consists of a conductive portion and an insulated portion wherein the conductive portion is positioned between the contact pair in the switch-closed position. The insulating portion moves to a position between the cont'act pair when the switch is operated to open circuit position. This arrangementthereby positions ar member of high insulating valuebetween the contact pair and further acts to prevent the accumulation of ionized gases in the region between the contact pair. A s

The instant invention provides a switch assembly which minimizes the effect of ionizing gases and inhibits 'arcing by means of a novel contact pair and reciprocating member configuration which together with an operating mechanism provides rapid and complete current interruption. The switch assembly 0f the invention is comprised of an operating means coupled to the contact assembly reciprocating member.V U.S. Patent No. 3,217,130 describes the operating means. s The contact pair is arranged so that one contact is relatively stationary and the second contact is relatively movable. A biasing member abuts the relatively movable contact providing high magnitude contact pressure in the contact assembly. The biasing spring mounting enables the contacts of the contact pair to' be lcurved away from one another at theirwfree ends each forming an arcing contact configuration toA aid in the extinguishment of any electrical current arcs formed therebetween.

The contact arrangement described in the paragraph immediately above' has the vdisadvantage that vwith the switch in the closed position the direction of current flow in one arm of the contact pair is opposite in direction to the current flow in the second arm of the contact pair. These two current paths generate magnetic fields which tend to oppose one another subsequently tending to drive the two contact arms of the contact assembly away from one another thus, substantially decreasing the contact engagement between the arms `of the contactpair and the reciprocating metallic insert which is movable under control of the aforementioned toggle assembly. This arrangement thereby significantly alters the main current path. In order to overcome this undesirable feature, an alternative embodiment to the contact assembly has been provided which is comprised of rst and second pairs each pair having a rst andsecond contact arm which are positioned so as to receive and make firm engagement with opposing ends of the reciprocating metallic insert movable under control of the toggle assembly. The opposite ends of the first and second contact pairs are con- ICC nected to the current path serviced by the switch assembly. With this arrangement and with the metallic insert in the closed position, i.e., with the metallic insert engaging both arms of both contact pairs, the current path extends through the contact assembly in such a manner that the direction of current ow through the first and second arms of each contact pair both extend in the same direction. This is likewise true of the direction of current flow in the first and second arms of the second contact pair. In this arrangement the contactarms of each contact pair generate magnetic fields which react with the associated arm of the contact pair in such a manner as to urge the contacts toward one another thereby increasing the contact engagement between the first and second arms of each contact pair and the reciprocating metallic insert. y

The contact arms of each contact pair are further constructed so that the length of the side of each contact arm which faces its associated contact arm is substantially greater than the width of each contact arm. Thus with this arrangement, even though the rst and second contact pairs are positioned in a substantially side-by-side arrangement, the physical configuration of the contact arms are such that they cannot undergo any bending whatsoever in the direction parallel to their faces so that the inherent strength and rigidity of each contact arm, due to its physical configuration is such that the arms of each contact pair may not be influenced to any degree by the interacting magnetic fields between contact pairs. This arrangement thereby eliminates the occurrence of any contact low open conditions, while taking full advantage of contact low closed conditions.

In cases where circuit control for a multiphase system is desired, a unitary head is provided for mounting al1 of the reciprocating members. One end of the unitary head is coupled to the operating mechanism.

The switch housing is designed to compactly house the switch assembly. Guiding means are provided within the housing which cooperate with associated guide pins projecting from the unitary head for preventing the unitary switch head from experiencing any translational motion in directions transverse to the normal reciprocating motions.

Each switch assembly has a series connected fuse for each circuit to provide protection during overload or short circuit conditions. The fuse is mounted in mechanical parallel to its associated switch assembly providing a circuit interrupter assembly having extremely compact outside dimensions which are limited only by the dimensions of the fuses employed in the assembly. Openings are positioned along the housing adjacent each contact assembly for observation of the condition, i.e., open or closed position of the contact assembly. In installations where dust, humidity and other such objectionable environmental factors are present each opening may be fitted with transparent inserts to protect the switch assembly while retaining the observation feature.

Another object of this invention is to provide a novel `spring biased stationary contact assembly having stationary contact members which are curved at their free ends in directions away from one :another to provide a novel arcing contact conguration.

Another object yof this invention is to provide a novel contact assembly for circuit interrupters of the multiphase type wherein a novel unitary head is employed for mounting the reciprocating members of each contact assembly to provide simultaneous uniform opening and closing operations.

Another object of this invention is to provide a housing for a circuit interrupter having novel means for mounting a switch assembly and associated series connected fuse means.

Another object of this invention is to provide a hous- -in-g for a circuit interrupter having novel means for mounting a switch assembly and associated series connected fuse means wherein the series connected fuse means is mounted in mechanical parallel with its associated switch assembly.

Still another object of this invention is to provide a movable contact arrangement for circuit interrupters having a unitary head means which is designed to cooperate with guide means provided in the interrupter housing to control the motion of the contact Iassembly reciprocating member.

Yet another object of this invention is to provide a movable contact a-rrangement for circuit interrupters having a reciprocating contact which is designed to cooperate with a contact assembly having a novel arrangement to enhance contact pressure between the reciprocating member and the cooperating contact assembly when the circuit interrupter is in its ON position.

These and other objects -will become apparent upon reading the accompanying description and drawings in which:

FIGURE 1 is a perspective of the operating mechanism and the unitary head structure of the instant invention.

FIGURE 2 is a view in the direction 2 2 of FIG- URE 1.

FIGURE 3 is a top plan view of the circuit interrupter of this invention.

FIGURES 4 and 5 are end views of the opposing ends of the circuit interrupter of FIGURE 3.

FIGURE 6 is a perspective view of an interior portion of the circuit interrupter of FIGURE 3 showing the stationary contact assembly in greater detail.

FIGURE 7 is a cross-sectional view of the interrupter assembly of FIGURE 3 taken along the line 7-7.

FIGURE 7a is a View of the -unitary head structure and contact assembly of FIGURE 7 shown in the circuit closed position.

Referring to the drawings, FIGURE 1 shows switch operating mechanism 12 which is connected by links 15 and 16 to unitary mounting head structure 19', causing structure 19 to reciprocate in directions 13 and 14 in a manner detailed in U.S. Patent No. 3,217,130. The stationary contact structure shown in FIGURE 6 cooperates with the unitary mounting head structure 19 which can best be seen in FIGURES 1 and 2 and which is cornprised of an' elongated body 80 formed of an insulating material fand having three extensions 81, 82 and 83 eX- tending substantially perpendicular from the main body 80, each being formed integrally with the main body and each being formed of an insulating material. Each extension 81-83 is substantially rectangular and has a substantially rectangular cavity 84-86 respectively provided therein. A stationary insulating member 87, 88 and 89 is positioned in each cavity 84-86 respectively and is of such thickness as to be slidably engageable with the inner surfaces of the lcontact structure comprised of members 43a-c 4and 44a-c shown in FIGURE 6. Conductive members 90, 91 and 92 respectively are provided in the cavities 8486 and are positioned so as to be substantially in alignment with their associated guide members 87- 89 respectively. The conductive members 90-92 are positioned immediately behind their associated insulating means 87-89 respectively so that each insulating member such -as member 87 is substantially in alignment with its associated conductive member, such as for example the conductive member 90. The mounting head 19 is provided with grooves (not shown) which are so dimensioned as to permit some movement of the conductive members 9092 in a direction transverse to their longitudinal axis. This arrangement enables conductive members 90-92 to become property aligned between its associated contact pair when moved to the fully closed position as will be more fully described.

Unitary mounting head 19 further includes guide pins 93 and 94 for the purpose of cooperating with associated grooves (not shown) in the circuit interrupter housing to restrain the unitary mounting head 19 from any movement other than the reciprocating movement.

The circuit interrupter housing 200 can best be seen in FIGURES 36 and is comprised of a main shell 201 which is adapted to house the operating mechanism 12. The mechanism is positioned in the housing shell 201 in such a manner that the pins 93 and 94 of the unitary mounting head 19' are guided by the elongated grooves 202 and 203 provided along the floor of housing shell 201 (see FIGURES 6 and 7). With this arrangement the unitary mounting head 19 is in close proximity with the stationary contact structure comprised of -contact members 43a-c and 44a-c which can best be seen in FIG- URE 6. In this position the insulating members such as for example the insulating member 87 is positioned between the surfaces of contact members 43 and 44 when the operating mechanism 12 is in the fully open position (see FIGURE 7). When the operating mechanism 12 is moved to the fully closed position the unitary mounting head 19 moves in a direction shown by arrow 205 relative to the stationary contact structure -causing the conductive member such as for example the conductive member 90 to be positioned between the opposing faces of the contact members 43 and 44 (see FIGURE 7a). This provides a conductive path between the stationary contact members 43 and 44 which are connected to load and line terminals respectively in a manner to be more fully described.

Springs 45 apply pressure biasing relatively movable contacts 44a-c toward relatively stationary contacts 43a-c to ensure that a good contact between contacts 43 and 44 is obtained.

When the `operating mechanism is moved from the fully closed position to the fully open position the unitary head moves in the direction shown by arrow 206 relative to the stationary contact assembly causing the conductive member such as the conductive member 90 to become disengaged from the opposing surface-s of contact members 43a and 44a. The insulating member 87 however, slides into a position directly between the opposing surface of contact members 43a and 44a so as to prevent the accumulation of ionized gases in the immediate region of the contact members 43a and 44a thereby preventing the occurrence of any restrike of the arc. The outwardly curved free ends of stationary contact members 43a and 44a act as arcing tips which become areas for an arc toy travel when the switch is opened acting to stretch the length of the arc. This configuration substantially decreases burning in the portion where contact members are engaged by the conductive member 90 when the toggle assembly is in the fully closed position.

Alternative embodiments of head structure 19' and contacts 43a-c and 44a-c can be seen in FIGURES 19-22 of U.S. Patent No. 3,217,130.

Upper surface 206 of housing assembly 200 (see FIG- URES 3 and 7) is adapted to receive fuse holding assemblies which secure and electrically connect each fuse member with its associated double break contact structure. Since the structure for the fuse holding assembly is identical for each phase of the multiphase circuit interrupter only one such structure will be described. The fuse holding assembly is comprised of rst and second fuse clips 207 and 208, respectively, which are secured to housing cover 206 by means of screw members 209 and 210. The fuse clip 209 is electrically connected to stationary contact member 44 which is secured to the upper Isurface 206' of the housing assembly by screw member 211. The conductive path therebetween consists of fuse clip 207, metallic member 212, and contact member 44. Metallic member 212 is positioned in a cavity 213 pro.-

vided in the upper surface 2%' of the housing assembly which cavity acts to prevent any movement of metallic member 212. Screw member 211 simultaneously acts to secure metallic member 212 within cavity 213 and to further maintain metallic member 212 in firm engagement with the upper portion of contact member 411. The screw member 26% acts to electrically and mechanically connect fuse clip 2197 to metallic member 212. The contact member 43 is secured near the base of housing 2111 by screw member 214 and has its right-hand most end (see FIG- URE 7) in rigid engagement with the mounting terminal assembly 215. This assembly consists of a substantially rectangularly shaped member 216 (see also FIGURE 5) having a tapped screw member 217 for rigidly securing conductors positioned in the opening 218 formed by member 216 and screw member 217. A second screw member 218:1 is provided for rigidly securing rectangular member 216 to the right-hand most end of stationary contact 43 so as to provide good electrical connection therebetween. Thus the conductive path so far described (with the toggle assembly in its fully closed position) consists of the terminal means 215, stationary contact 43a, conductive member 90, stationary contact 44a, metallic member 212 and fuse clip 207.

The cooperating fuse clip 208 is secured by screw member 216i to an elongated metallic member 220. The screw member 210 acts to secure both the fuse clip 208 and the elongated metallic member 220 to the upper surface 266 of the housing assembly. The opposite end 221m of elongated metallic member 220 is positioned within the left-hand end of cavity 213 so as to prevent any movement thereof. A second terminal connector assembly 221 is provided which assembly is secured to a projecting ear portion h of elongated metallic member 221). This terminal assembly is identical in structure to the terminal assembly 215 and is comprised of a substantially rectangularly shaped member 222 having a tapped aperture for receiving screw member 223 employed for rigidly securing a conductor within the cavity 223 formed between the screw member 221 and the rectangularly shaped member 222 (see FTGURE 4). The fuse member is mounted between the associated fuse clips in the manner shown with respect to phases b and c in FIGURE 3 thereby establishing a conductive path between associated fuse clips such as for example the fuse clips 207 and 2118. The entire conductive path through the circuit interrupter is therefore as follows:

Terminal means 215, stationary contact 43a, metallic member 90, stationary contact 44a, metallic member 212, fuse clip 207, fuse 229 (shown in FIGURE 7), fuse clip 20S, conductive member 220 and terminal means 221. As can clearly be seen, this arrangement provides a conductive path through a series connected fuse and double break switch assembly which elements are physically arranged in mechanical parallel. This thereby provides an extremely compact circuit interrupter assembly.

The elongated conductive member 220 is provided with a plurality of tapped apertures 231 along its length .for the purpose of mounting the fuse clip 208 in a variety of positions so as to accommodate fuses of varying lengths. In order to isolate adjacent phases of the circuit interrupter assembly the housing assembly upper surface 206 is provided with elongated grooves such as for example the groove FGURE 3 for receiving an insulating barrier such as the insulating barrier 233 shown in FIGURES 4 and 5.

Apertures 235 and 236 are provided in the upper and lower surfaces of the housing assembly which can best be seen in FIGURES 3 and 7. The upper aperture 235 provided in the housing upper surface 266 is adapted to receive the manual operating handle 237 shown in FIG- URES 4 and 5. Handle 237 is described in U.S. Patent No. 3,217,130.

Openings 260 which can best be seen in FIGURES 3 and 6 are provided in the upper surface 206 of the housing assembly to permit observation of the contact assembly positioned immediately below each opening 260. In the fully closed position the contact members 43a-c and 44a-c are covered by the extending portions 81-83 .of the unitary head means 19' (see FIGURE 2) and are therefore not visible at this time. When the operating mechanism is moved to the fully tripped or open position the contact members are observable in this position so as to permit a visual inspection for maintenance or other purposes. In situations where it is desired to cover the apertures 26@ for protecting the circuit interrupter toggle assembly against dust, gases or other foreign matter, small insulating pieces having the same configuration as openings 261i may be snapped over the open areas and retained in this position by molded extensions 260a provided along the sides of each opening 260. If it is desired to prevent the introduction of such foreign matter while at the same time permitting observation of the contacts contained within the housing, the inserts employed may be formed of a transparent material.

t can therefore be seen that this invention provides a novel circuit interrupter assembly having an operating mechanism and which is designed so that the series connected fuse associated with each double break contact assembly of the multiphase circuit interrupter is positioned in mechanical parallel with its associated contact assembly to provide a compact structure. While the preferred embodiment described herein is a multiphase circuit interrupter assembly, it should be understood that this invention operates equally as well with a greater or lesser number of phases.

Although there has been described a preferred embodiment of this novel invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appending claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A reciprocating assembly for use in a multiphase circuit interrupter wherein each phase is comprised of a stationary Contact pair and is controlled by a circuit interrupter operating mechanism comprising an insulating body portion, first means contained within said body portion for coupling said operating mechanism to each of said contact pairs; said first means comprising a plurality of portions projecting from said body portion, each associated with one phase of said multiphase breaker, each projecting portion extending in a direction substantially perpendicular to said body portion, and having a cavity of a configuration to position the ends of the contacts facing said projection portion substantially within at least the opening of said cavity; an insulating means mounted within said cavity adjacent the opening thereof and positioned to slideably engage the opposing faces of said contact pair; a conductive member mounted within said cavity behind said conductive member and positioned to slideably engage the opposing faces of said contact pair when said circuit interrupter is moved to its closed position; said conductive member resiliently mounted at the end adjacent said insulating means for self alignment of said conductive member with said contact pair to provide a suflicient conductive path therebetween; a housing for said circuit interrupter; said housing having a plurality of apertures; each aperture being positioned adjacent an associated said contact pair and for observation of said contact pair when said circuit interrupter is in the tripped position and to prevent observation of said contact pair when said circuit interrupter is in the closed position so as to permit observation thereof only when each contact pair is fully deenergized; a plurality of transparent inserts mounted to cover each of said housing apertures to permit observation of said contact pairs while excluding foreign matter from said housing interior; a plurality of fuse clip assemblies mounted upon the upper surface of said housing, each assembly having first and second fuse clips .adapted to -receive a fuse member therebetween; said fuse clips mounted in mechanical parallel with its associated contact pair; each of said assemblies connected in electrical series with its associated contact pair.

2. The reciprocating assembly of claim 1 wherein said housing upper surface is provided with elongated grooves positioned between adjacent phases; a plurality of barrier means engaged by an associated groove for isolating each of said fuse assemblies.

3. The reciprocating assembly of claim 1 wherein a plurality of conductive assemblies electrically connects each fuse assembly to its associated contact assembly; said conductive assembly including fastening means adapted to simultaneously fasten one of said fuse clips and one contact of said contact pair to said conductive assembly and further adapted to insure a continuous sumcient current path therethrough.

No references cited.

BERNARD A. GILHEANY, Primary Examiner.

H. A. LEWITTER, Assistant Examiner.

Claims (1)

1. A RECIPROCATING ASSEMBLY FOR USE IN A MULTIPHASE CIRCUIT INTERRUPTER WHEREIN EACH PHASE IS COMPRISED OF A STATIONARY CONTACT PAIR AND IS CONTROLLED BY A CIRCUIT INTERRUPTER OPERATING MECHANISM COMPRISING AN INSULATING BODY PORTION, FIRST MEANS CONTAINED WITHIN SAID BODY PORTION FOR COUPLING SAID OPERATING MECHANISM TO EACH OF SAID CONTACT PAIRS; SAID FIRST MEANS COMPRISING A PLURALITY OF PORTIONS PROJECTING FROM SAID BODY PORTION, EACH ASSOCIATED WITH ONE PHASE OF SAID MULTIPHASE BREAKER, EACH PROJECTING PORTION EXTENDING IN A DIRECTION SUBSTANTIALLY PERPENDICULAR TO SAID BODY POTION, AND HAVING A CAVITY OF A CONFIGURATION TO POSITION THE ENDS OF THE CONTACTS FACING SAID PROJECTION PORTION SUBSTANTIALLY WITHIN AT LEAST THE OPENING OF SAID CAVITY; AN INSULATING MEANS MOUNTED WITHIN SAID CAVITY ADJACENT THE OPENING THEREOF AND POSITIONED TO SLIDEABLY ENGAGE THE OPPOSING FACES OF SAID CONTACT PAIR; A CONDUCTIVE MEMBER MOUNTED WITHIN SAID CAVITY BEHIND SAID CONDUCTIVE MEMBER AND POSITIONED TO SLIDEABLY ENGAGE THE OPPOSING FACESF OF SAID CONTACT PAIR WHEN SAID CIRCUIT INTERRUPTER IS MOVED TO ITS CLOSED POSITION; SAID CONDUCTIVE MEMBER RESILIENTLY MOUNTED AT THE END ADJACENT SAID INSULATING MEANS FOR SELF ALIGNMENT OF SAID CONDUCTIVE MEMBER WITH SAID CONTACT PAIR TO PROVIDE A SUFFICIENT CONDUCTIVE PATH THEREBETWEEN; A HOUSING FOR SAID CIRCUIT INTERRUPTER; SAID HOUSING HAVING A PLURALITY OF APERTURES; EACH APERTURE BEING POSITIONED ADJACENT AND ASSOCIATED SAID CONTACT PAIR AND FOR OBSERVATION OF SAID CONTACT PAIR WHEN SAID CIRCUIT INTERRUPTER IS IN THE TRIPPED POSITION AND TO PREVENT OBSERVATION OF SAID CONTACT PAIR WHEN SAID CIRCUIT INTERRUPTER IS IN THE CLOSED POSITIONS SO AS TO PERMIT OBSERVATION THEREOF ONLY WHEN EACH CONTACT PAIR IS FULLY DEENERGIZED; A PLURALITY OF TRANSPARENT INSERTS MOUNTED TO COVER EACH OF SAID HOUSING APERTURES TO PERMIT OBSERVATION OF SAID CONTACT PAIRS WHILE EXCLUDING FOREIGN MATTER FROM SAID HOUSING INTERIOR; A PLURALITY OF FUSE CLIP ASSEMBLIES MOUNTED UPON THE UPPER SURFACE OF SAID HOUSING, EACH ASSEMBLY HAVING FIRST AND SECOND FUSE CLIPS ADAPTED TO RECEIVE A FUSE MEMBER THERBETWEEN; SAID FUSE CLIPS MOUNTED IN MEHCANICAL PARALLEL WITH ITS ASSOCIATED CONTACT PAIR; EACH OF SAID ASSEMBLIES CONNECTED IN ELECTRICAL SERIES WITH ITS ASSOCIATED CONTACT PAIR.

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