US3343042A - Switchboard apparatus - Google Patents

Description

P 1967 A. R. CELLERINI ETAL I 3, 343,Q42

SWITCHBOARD APPARATUS v s Sheets-Sheet 1 Filed Nov. 5, 1964 8 mm. m9 H S p 1967 A. R. CELLERINI ETAL .SWITCHBOARD APPARATUS 6 Sheets-Shet 2 Filed Nov. 5, 1964 A. R. CELLERINI ETAL SWITCHBOARD APPARATUS Sept. 19, 1967 Filed Nov. 5, 1964 3,343,042 1 6 Sheets-Sheet 5 S p 1967 A. R. CELLERINI ETAL 3,343,042 YSWITCHBOARD APPARATUS 6 Sheets-Sheet 4 Filed Nov. 5, 1964 FIG-7.

IIIIIEL I Sept. 19, 1967 A. R. CELLERINI ETAL 3,343,042

S WITCHBOARD APPARATUS Filed Nov. 5, 1964 6 Sheets-Sheet 6 United States Patent 3,343,042 SWITCHBOARD APPARATUS Albert R. Cellerini, Beaver, and Louis N. Ricci, Chippewa Township, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Nov. 5, 1964, Ser. No. 409,244 8 Claims. (Cl. 317-112) This invention relates generally to switchboard apparatus and more particularly to switchboards of the type comprising plug-on type circuit breakers. This invention also relates to plug-on type terminal connectors.

A general object of this invention is to provide an improved switchboard.

Another object of this invention is to provide an improved switchboard comprising a circuit breaker with means automatically tripping the circuit breaker under certain predetermined conditions.

Another object of this invention is to provide an improved switchboard comprising a plug-on type circuit breaker which improved means for moving the circuit breaker into and out of operating position on the switchboard.

Another object of this invention is to provide an improved circuit breaker.

Another object of this invention is to provide an improved compactly constructed molded-case type circuit breaker.

Another object of this invention is to provide an improved plug-on type circuit breaker that can carry increased current with a minimum of heating.

A further object of this invention is to provide an improved plug-on type terminal connector.

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

In said drawings:

FIGURE 1 is a side sectional View, taken generally along the line I-I of FIG. 2, illustrating a circuit breaker constructed in accordance with principles of this invention;

FIG. 2 is a top plan view, with parts broken away, of the circuit breaker seen in FIG. 1;

FIG. 3 is a sectional view of the separately enclosed trip unit of the circuit breaker taken generally along the line III-III of FIG. 1;

FIG. 4 is a side sectional view through the center pole unit of the trip device of FIG. 3 with the circuit-breaker safety tripping structure being shown in cooperating relationship with the trip unit;

FIG. 5 is a side view of one of the contact plug-on type terminal connectors seen in FIG. 1;

FIG. 6 is an isometric view, on a substantially smaller scale relative to the scale of FIGS. 1-5, of a switchboard or control center comprising at least one circuit breaker of the type disclosed in FIGS. 1 and 2, and embodying principles of this invention;

FIG. 7 is a side sectional view with parts broken away illustrating a circuit breaker in operating position in one of the compartments of the switchboard unit seen in FIG. 6;

FIG. 8 is a partial view similar to FIG. 7 illustrating the position of certain parts of the structure seen in FIG. 7 when the switchboard door is in the open position;

FIG. 9 is a sectional view, taken generally along the line IXIX of FIG. 8 and illustrated on an enlarged scale relative to FIG. 8;

FIG. 10 is an end view, on an enlarged scale relative to FIG. 4 of part of the tripping structure seen in FIG. 4;

FIG. 11 is a view similar to FIG. 7 with the circuit breaker being shown in a disconnected position;

FIG. 12 is a top plan view of the carriage structure seen in FIGS. 7 and 11;

FIG. 13 is an elevational view of part of the structure seen in FIG. 12 which part is identified by the line XIIIXIII in FIG. 12;

FIG. 14 is an elevational view of the bell-crank lever member disclosed in FIGS. 7 and 11;

FIG. 15 is a side view of part of the structure seen in FIGS. 7 and 11 With part of the disclosed terminal being rotated to a different position from that seen in FIGS. 7 and 11;

FIG. 16 is a plan view of one of the terminal structures seen in FIGS. 7 and 11; and

FIG. 17 is a sectional view taken generally along the line XVII-XVII of FIG. 16.

Referring to the drawings, there is shown in FIGS. 1 and 2 a circuit breaker 3 comprising an insulating housing 5 and a three-pole circuit breaker mechanism supported within the housing. The housing 5 comprises a base 9 and a cover 11 both of molded insulating material.

The circuit-breaker mechanism 7 comprises an operating mechanism 13 and a trip unit 15. The circuit breaker is a three-pole circuit breaker comprising three compartments disposed in a side-by-side relationship. The center compartment is separated from each of the two outer compartments by means of a separate pair of cooperating insulating barriers 17 and 19 molded integrally with the circuit breaker base 9 and cover 11 respectively. At the two opposite ends of the circuit breaker each compartment is closed off by means of two insulating barriers 20 that are suitably secured to the housing base and cover 11. The removable three-pole trip unit 15, which extends transversely across the internal width of the circuit breaker will be hereinafter specifically described. The operating mechanism 13, that is disposed in the circuit breaker center pole unit or compartment, is a single operating mechanism for operating the contacts of all three pole units.

Each pole unit comprises a stationary contact 21 that is fixedly secured to a rigid main conductor 23 that is secured to the base 9 by means of bolts 25. In each pole unit, a movable contact 27 is Welded or brazed to a contact arm 29 that is pivotally mounted on a switch arm 31 by means of a pivot pin 33. Each of the switch arms 31 is pivotally supported'at one end thereof on a separate support bracket 34 by means of a separate pivot pin 35. The switch arms 31 for all three of the pole units are connected to move in unison by means of a common tie bar 37 that is rigidly connected to all three of the switch arms. Each of the contact arms 29 is biased about the associated pivot 33 by means of a separate spring 39 to provide contact pressure in the closed position of the contacts.

The switch arms 31 are operated to the open and closed positions by means of the common operating mechanism 13. The operating mechanism 13 comprises a toggle link 41 that is pivotally connected to an extension 43 of the center pole switch arm 31 by means of a pivot pin 45. The togglelink 41 is pivotally connected to the lower end of another toggle link 47 by means of a knee pivot pin 49. The upper end of the toggle link 47 is pivotally connected to a cradle or releasable member 51 by means of a pivot pin 53. The cradle 51 is pivotally supported at one end thereof on the supporting bracket 34 by means of a pivot pin 57. The other end 59 of the releasable member 51 is held in a latched position by means of a latch member 61. The operating mechanism 13 also comprises an inverted generally U- shaped operating lever 63 that is pivotally supported on th bracket 34 by means of pins 65 that engage the inner ends of the legs of the operating lever 63. An actuating insulating shield 67, for substantially closing an opening 69 in the cover 11, is secured to the upper end of the operating lever 63. An insulating handle portion 71 ex tends from the shield 67 out through the opening 69 to permit manual operation of the breaker. Two overcenter springs 75 (only one being shown in FIG. 1) are connected under tension between the knee pin 49 of the toggle 41, 47 and the upper end of the operating lever 63. Pin means 77 are secured to the upper end of the lever 63 in order to support the upper ends of the springs 75.

In each pole unit, an arc-extinguishing unit 81 is provided to extinguish the are drawn between the associated contacts 21, 27. Each arc-extinguishing unit comprises an insulating housing 83 and a plurality of magnetic steel plates 85 supported within the housing 83. The moving contact 27 moves within a generally V-shaped opening 87 (FIG. 2) in the stacked plates 85, and the are drawn between the contacts 21, 27 is magnetically moved to the right (FIGS. 1 and 2) into the plates 85 to be extinguished during a circuit interrupting operation. Each of the arc-extinguishing units 81 is secured to the associated main conductor 23 (FIG. 1) by means of four bolts 89 that are threaded into tapped openings in the conductor 23.

At each of the three-pole units, the circuit breaker 3 is provided with two plug-on type terminal connectors 91 that are suitably secured at opposite ends of the circuit breaker. The plug-on type terminal connectors 91 will be hereinafter more specifically described.

The circuit through each pole unit of the circuit breaker 3 extends from the right-hand (FIG. 1) terminal 91 through the conductor 23, the contacts 21, 27, the contact arm 29, flexible conductors 93 that are secured at one end to the contact arm 29 and at the other end to a terminal conductor 95, through the terminal conductor 95 that is secured to the base by means of a screw 97, a unitary rigid main conductor 99 that is connected to the terminal conductor 95 and is secured to the base by means of bolts 101 and 103, to the other terminal connector 91. The bolts 101 and 103 are threaded into inserts 105 in the base 9 to secure the main conductor 99 to the base. Each of the rear-type plug-on terminal connectors 91 is connected to the associated internal conductor (23 or 99), by means of four bolts 107 that are disposed at the four corners of an imaginary square. Only two bolts for each of the connectors 91 are disclosed in FIG. 1. As can be seen in FIG. 2, the section in FIG. 1 is shown at the left in the outer pole unit and it jogs into the center pole unit in order to more clearly disclose the operating mechanism which is a single mechanism only in the center pole unit of the circuit breaker. It is to be understood that each of the circuits through each of the three pole units comprises the same kind of structure as that hereinbefore described with respect to the parts that are illustrated in FIG. 1.

The circuit breaker 3 is disclosed in FIG. 1 in the closed or on position. The circuit breaker, is manually operated to the open or off position by movement of the handle 71 in a counterclockwise direction to the 011 position. During this movement, the line of action of the overcenter spring means 75 is moved to the left to an overcenter position to efiect a collapse of the toggle 41, 47 to pivot the switch arm 31 for the centerpole in a counterclockwise direction about the associated pivot 35 to an open position. This movement of the, center pole switch arm 31, because of a rigid connection of all of the switch arms- 31 by means of a rigid common tie bar 37, simultaneously moves all of the three switch arms 31 to the open position.

The circuit breaker is manually closed by reverse movement of the handle 71 from the off to the on position.

This movement moves the operating lever 63 to move the line of action of the overcenter spring means to the right to thereby straighten the toggle 41, 47 moving all three of the switch arms 31 simultaneously to the closed position seen in FIG. 1.

Referring to FIGS. 1-4, the trip device 15 comprises a molded insulating base 113 and a molded insulating cover 115 cooperable with the base to enclose three thermal magnetic tripping means which are disposed within three compartments in the housing 113, 115. The compartments are separated by means of insulating barriers 117. The trip device 15 includes a molded insulating trip bar 119 that passes through suitable openings in the barriers 117 and is common to all three of the pole units. The trip bar 119 is pivotally supported on a bracket 121 that extends out of the base 113 and is supported on a suitable supporting bracket 123. A separate laminated U-shaped magnetic core 125 for each pole unit is suitably mounted in the associated compartment of the trip device 15 by means of bolts 127 that secure the core to the trip-unit base 113. As can be seen in FIGS. 3 and 4, each of the main conductors 99 passes through the opening in the U-shaped magnet 125 and is held in place by means of a bolt 129. A separate movable armature 131 is pivotally supported on one leg of each of the cores 125. Each armature is biased to an opened position'by means of a separate spring 133. A rod 135 is pivotally connected to each armature 131 and a head portion 137 on each rod 135 is adapted to engage and operate the trip bar 119 upon sutficient energization of the electromagnet 125, 131. Each tripping electromagnet is energized by current flowing in the associated main conductor 99.

The circuit breaker is tripped open instantaneously by operation of any one of the tripping electromagnets. When one of the tripping electroma-gnets is energized by an overload current above a predetermined value or by means of a short circuit, the armature 131 is attracted and the free end thereof is moved into engagement with the other leg of the magnet yoke 125 during which movement the rod 135 is pulled down, whereupon the head 137 of the rod 135 engages the trip bar 119 causing the trip bar to rotate in a counterclockwise (FIG. 4) direction. This movement effects a releasing movement of the latch 61 to disengage the latch 61 from the cradle 51 (FIG. 1). Upon release of the cradle 51, the springs 75 act to rotate the cradle in a clockwise direction about the pivot 57 and to collapse the toggle 41, 47 to thereby pivotally move the three switch arms 31 in a counterclockwise (FIG. 1) direction to the open position.

During the automatic opening operation the line of force of the spring means 75 operates to move the operating lever 63 and handle 71 to an intermediate position between the on and off positions in a well known manner to thereby provide a visual indictaion that the circuit breaker has been automatically tripped.

Following an automatic opening operation, it is necessary to reset and relatch the circuit breaker mechanism before the contacts can be closed. This is effected by movement of the handle 71 to the full off position. During this movement, a pin 137 that is supported on the operating lever 63, engages a shoulder 139 on the cradle 51 moving the cradle in a counterclockwise direction about the pivot 57. Near the end of this movement, the free or latching end 59 of the cradle 51 cams the latch 61 to the left against the bias of spring means (not shown) and moves below the latching end of the latch 61 whereupon the latch 61 is biased back to the latching position seen in FIG. 1 to relatch the cradle 51 in a well known manner. The breaker contacts are then closed in the previously described manner by movement of the handle to the on position.

An adjusting mechanism is provided for adjusting the position of each armature 131 to provide for selection of the minimum overload current that will be required to instantaneously trip the circuit breaker. The adjusting mechanism is of the type that is specifically described in the patent to Glenn R. Thomas et al., Pat. No. 3,073,- 925. Thus, only a brief description of the adjusting mechanism is given herein. The adjusting mechanism comprises a cam member 141 having an upper cam surface that is engaged by one end of a lever 143. The lever 143 is pivotally supported intermediate its ends on a supporting bracket 147 that is attached to the yoke 125 and housing 113 by means of rivets 127. A rod 145 extends from the cam 141 to an adjusting knob 149 that passes out through a suitable opening in the trip unit housing 113, 115. Rotation of the adjusting knob 149 rotates the cam 141 to thereby pivot the lever 143 whereupon an adjusting screw 151 on one end of the lever 143 moves against the associated armature 131 to pivot the armature 131 varying the magnetic air gap and therefore the minimum overload current that will magnetically trip the circuit breaker.

Thermal tripping means is provided to effect automatic tripping of the circuit breaker with a time delay upon the occurrence of lower overload current conditions. The thermal tripping means comprises another U-shaped laminated magnet yoke 155 (FIG. 4) through which the conductor 99 passes. An unlaminated magnetic bar 157 connects the upper legs of the magnet yoke 155. A bimetal member 159 is supported on a conducting coil 161 that is disposed over the bar 157. Upon the occurrence of an overload current below a predetermined value, the hysteresis losses in the bar 157, which occur in the form of heat, will be conducted to the bimetal 159 and heat generated by eddy currents in the coil 161 will be conducted to the bimetal 159 whereupon the heated bimetal will bend to the left (-FIG. 4) to engage an adjusting screw 165 that is supported on the trip bar 119 to thereby rotate the trip bar 119 to effect a tripping operation of the circuit breaker in the same general manner as was hereinbefore described.

As can be seen in FIG. 1, the trip device 15 is secured to the circuit breaker by means of bolts 101 and 103 that secure the three rig-id conductors 99 for the three pole units to the base 9. The trip device 15 and conductors 99 comprise a unitary removable structure whereby the trip units are interchangeable so that the breaker can accommodate other trip units having different current carrying capacities. It can be seen in FIG. 3 that there are three conductors 99 extending through the trip device 15 for the three pole units of the trip device. Each of the conductors 99 conducts the current in the associated pole unit along the length of the circuit breaker. In each pole unit a reartype and plug-on type terminal connector 91 is supported on and directly connected to the associated conductor 99 by means of four bolts 107 (only two of which are seen in FIG. 1). In each pole unit an opening 167 is provided in the housing base 9 to receive the terminal connector 91 that is connected to the conductor 99. In each pole unit, the terminal connector 91 on the right (FIG. 1) passes through a separate opening 168 in the housing base 9 and is connected directly to the rigid internal conductor 23 by means of four bolts 107 (only two of the bolts 107 being seen in 'FIG. 1).

As can be seen in FIGS. 1 and 2, the circuit breaker housing 5 comprises a front or top 181, a back or bottom 183, and side wall means comprising two side walls 185 and two end walls 187. The handle 71 extends through the opening 69 in the front of the housing. The openings 167 and 168 in the back of the housing permit connections between the terminal connectors 91' and the conductors 23 and 99. The arc-extinguishing units 81 extend substantially to the adjacent end wall 187.

As can be seen in FIGS. 1 and 5, each of the terminal connectors 91 comprises a generally T-shaped rigid conducting support part 189. The arm parts of the support part 189 have openings therein for receiving the bolts 107 that are screwed into tapped openings in the conductor 99 or 23 to mount the terminal structure 91 on the conductor 99 or 23 with a generally flat upper face of the terminal connector support part 189 engaging a generally flat lower face of the conductor 99 or 23. The leg portion 193 of the support part 189 of the terminal connector 91 extends in a direction generally normal to the upper flat connecting surface of the support part 189 and this leg portion is provided with openings therein for receiving three bolts or rivets 195 that secure a plurality of contact members to the leg portion 193. The openings in the arm parts of the support 189 are disposed at the four corners of an imaginary square and the tapped openings in the conductors 99 and 23 are disposed at the four corners of an imaginary square. Thus, each of the terminal connector structures 91 can be rotated and secured to the associated main conductor 99 or 23 in the same general manner as that hereinbefore described.

As can be seen in FIGS. 1 and 5, a contact structure comprising two outer contact members 201, two intermediate contact members 203 and two inner contact members 205 is supported on the support part 193 of the conducting support 189 by means of the three rivets 195. Each of the contact members 201, 203 and 205 comprises an elongated sheet metal conducting member having a plurality of slot portions 209 (FIG. 5) therein to form a plurality of contact fingers. As can be seen in FIG. 5, each of the contact members of the specifically described contact structure is split to provide five separate contact fingers. Each of the contact fingers is bent over at the outer end thereof to provide a general-1y rounded portion forming a contact surface 213 (FIG. 1). There are thirty contacts or contact surfaces 213 on each of the connectors 91.

The contact members 201, 203 and 205 comprise members of good conducting material having good spring characteristics or resiliency. Copper and silver are examples of good basic conducting materials, and when anyone of these materials is alloyed in order to provide the desirable resiliency, the alloyed material can be effectively utilized as the material forming the contact fingers of this invention. For example, the contact members can be formed from a beryllium copper alloy, a zirconium copper alloy or a cadmium copper alloy. A specific example of a suitable contact member is a contact member formed from a beryllium copper alloy having the composition of about 98% copper, 1% beryllium and 0.2% nickel. The contact members may be formed by any suitable method.

The circuit breaker is shown in FIG. 11 in the disconnected position and in FIG. 7 in the connected position. In the connected position the terminal connectors 91 are connected to conducting stabs 214. It can be understood that as the circuit breaker is moved into the connected position the contact members 201 are the first to engage the stabs 214 and these contact members are spread apart as they move into further engagement with the stabs 214; then the intermediate contact members 203 engage the stabs 214 and are biased apart by the stabs and finally the inner contact 205 engage the stabs 214 to be biased apart by the stabs. The resiliency of the contact members provides a spring bias against the stabs 214 to provide good contact pressure in the connected position seen in FIG. 7. As can be seen in FIG. 7, although the stabs 209 are progressively wider from left to right, the contact pressure between the different pairs of contact members is substantially the same because the contact members 201 which are spread furthest apart in the connected position are the longest contact members and the contact members 205 which are spread apart the least are the shortest contact members.

With the provision of three pairs of contact members each of which contact members comprises five resilient contact fingers, each of the contact structures 91 will make contact with the associated stab 214 at thirty different contact points 213. Thus, the circuit breaker will be able to carry increased currents with less heat rise. An

advantage of the provision of three different pairs of contact members that progressively engage the associated stab conductor is that the force required to initially and then progressively make contact can be less for the same amount of effective contact engagement, than that required if, for example, only one row or pair of contact arms were used.

Referring to FIG. 6, there is shown therein a control center or switchboard 217 comprising a cabinet structure 219 having six compartments therein each of which compartments is provided with an opening at the front of the cabinet that is covered by means of an openable door 221. Each of the doors 221 is pivotally mounted on the cabinet structure 219 by means of hinges 223. Each of the doors 221 is provided with a suitable opening 225 therein for receiving the operating handle 71 of an enclosed circuit interrupter when the door is moved to the closed position. Thus, the enclosed circuit interrupter or circuit breaker 3 can be manually operated when the door 221 is in the closed position. The switchboard 217 may have more or less than six compartments therein and it may be constructed in any of a number of ways that are well known in the art.

Referring to FIGS. 7 and 11, within each of the compartments of the control center there is supported a back supporting plate 229 and a bottom support member 231 that is suitably secured to the back plate 229. The back plate 229 is a generally flat plate member having six openings therein for receiving six terminal structures 233 (FIGS. 16 and 17). As is seen in FIGS. 16 and 17, each of the terminal structures 233 comprises an insulating block 234 having an opening 235 therein. Each of the insulating blocks 234 is provided with four openings 237 at the four corners thereof for receiving four screw members that are threaded into tapped openings in the back plate 229 to mount the terminal structure on the back plate 229. The insulating block 234 is also provided with four openings 241 therein for receiving four bolts 243. The stab member 214 is a generally T-shaped (FIG. 17) rigid conducting member that is positioned in a cavity 245 in the support 233 with the flat rear surface thereof engaging the flat rear surface of a rigid generally T- shaped conductor 247. The bolts 243 rigidly secure the members 214 and 247 together and support these members on the insulating block 234 which is in turn supported on the back plate 229 by means of the bolts that fix into the openings 237 (FIG. 16). Metallic inserts 248 are provided in the openings 241 to prevent damage to the insulating block 234 upon operation of the bolts 243. The conductor 247 is provided with openings 251 (FIG. 17) therein for receiving bolts 253 (FIGS. 7 and 11) that are used to connect the conductor 247 to one of the bus bars 255 that are suitably supported in the switchboard enclosure (FIG. 6) in a manner well known in the art. As can be seen in FIG. 16, the bolts 243 are disposed at the four corners of an imaginary square so that the members 247 and 214 can be rotated 90 and still be connectable to the support 233 in the same manner described. Moreover, with the openings in the members 214 and 247 being disposed at the four corners of an imaginary square, either of these members 214 or 247 can be rotated 90 relative to the other member and still be connectable to the other member in the same manner hereinbefore described.

Referring to FIGS. 7 and 11, two side plates 259 are suitably secured to and supported on the back plate 229. The side plates 259 are spaced to receive the circuit breaker 3 in a manner to be hereinafter described. Only one of the side plates 259 is visible in FIGS. 7 and 11', but it can be understood that a pair of these identical side plates 259 are used to support the associated circuit breaker. Each of the side plates 259 is provided with an elongated slot 261 therein that is opened at the outer end of the plate 259. The slots 261 cooperate to form a track to receive rollers 263. The circuit breaker 3 is supported on a carriage 265 (FIG. 12) that comprises two side plates 267 and two back braces 269 (FIGS. lland 12). Each ofthe back braces 269 is provided with two openings 271 (FIG. 12) therein. Four bolts 273 (FIG. 11) that are disposed in four openings 275 (FIGS. 11 and 12) in the insulating housing 5 of the circuit breaker 3 are threaded into the tapped openings 271 to secure the circuit breaker 3 to the carriage 265. As can be seen in FIG. 2, the openings 275 in the housing 5 are provided in the insulation between the pole units of the circuit breaker 3. The four rollers 263 (FIG. 12) are suitably secured to the side plates 267.

A locking member 279 (FIG. 13) is pivotally supported intermediate the ends thereof on one of the side plates 267 by means of a pivot pin 281. A spring member 283 is supported under tension between one end of the locking member 279 and a stationary pin 284 on the side plate 267 to bias the locking member in a clockwise direction (FIGS. 7, 11 and 13) about the pivot 281. The member 279 is provided with a pin 285 that passes through a suitable opening 287 (FIG. 13) in the side plate 267 to limit movement of the lever 279 in both directions. The pin 285 is provided to cooperate with three notches 289, 291 and 293 in the side plate 259 in a manner to be hereinafter described.

When it is desired to mount the circuit breaker 3 in the desired position on the switchboard, the circuit breaker structure 300, which comprises the molded-case circuit breaker 3 and the carriage 265, is moved into the position seen in FIG. 11 wherein the rollers 263 are engaged in the tracks 261 in the opposite side supporting plates 259. As the circuit breaker structure is moved to the FIG. 11 position the members 279, unless manually held in the unlocking position, will be automatically moved to locking positions with the pins 285 being biased first into the notches 293 and then into the notches 291. The members 279 are manually operable out of the locking positions by counterclockwise (FIG. 11) movement about the pivots 281. Each of the side plates 267 of the carriage 265 is provided with an opening 301 at the upper end thereof to receive a hook part of a crane that may be used to move the circuit breaker structure 300 into the position seen in FIG. 11. With the circuit breaker structure 300 in the position seen in FIG. 11, a bell-crank lever 305 (FIG. 14) is placed in the position seen in FIG. 11 wherein an elongated slot 307 thereof receives a pin 309 that is fixedly supported on one side plate 267 and wherein a slot portion 311 at one end thereof receives a pin 313 that is fixedly supported on the supporting side plate 259. If desired, a similar bell-crank lever 305 can be simultaneously utilized at the other side of the circuit breaker structure 300. With the bell-crank 305 in the position seen in FIG. 11, an operator manually rotates this member in a clockwise (FIG. 11) direction whereupon the circuit breaker structure 300 is moved into the connected position seen in FIG. 7. When the circuit breaker structure 300 reaches the fully connected position seen in FIG. 7, the spring member 283 will bias the lever 279 to move the pin 285 into the slot 289 to thereby lock the circuit breaker structure 300 in the fully connected position.

When it is desired to move the circuit breaker structure 300 to a disconnected position on the switchboard, the locking lever 279 is depressed to release the pin 285 from the slot 289. The bell crank lever 305 is then rotated in a counterclockwise direction to cam the circuit breaker structure 300 out to a fully disconnected position, and at the end of this movement, the locking pin 285 of the locking lever 279 will snap into the slot 291 to automatically lock the circuit breaker structure 300, in the disconnected position. The slots 293 are provided to be used as an additional locking slot when extensions (not shown) are used to elongate the tracks 261.

As can be seen in FIGS. 7, 8, 9, and 11, there is supported on the support 231 a safety trip structure 318 comprising a cam plate member 319 that is secured to the support 231 by means of two screws 321 (FIG. 9). The cam plate 319 is provided with an offset portion 323 having two bent-over portions 325 that extend upward from the support 231. Each of the parts 325 is provided with an opening therein, and a cam member 327 is movably supported in these openings. The cam member 327 is provided with a cam part 329 at one end thereof (FIG. 8). A spring support 331 is fixedly secured to the member 327, and a compression spring 333 is disposed over the member 327 and biased between the member 331 and the one support part 325 to bias the cam member 327 to the left as seen in FIGS. 7, 8 and 9.

Referring to FIGS. 4 and 10, there is shown therein a tripping device 341 comprising a first part 343 and a second part 345. Three insulating supports 347 are supported in one end of the center pole compartment of the circuit breaker 3. The supports 347 are supported in suitable slots in the insulating housing parts 9 and 11. Each of the supports 347 is provided with an opening therein, and the members 345 and 343 are disposed within the openings to be supported on the circuit breaker. The part 343 has a pin member 349 thereon that engages one barrier 347 to limit outward movement of the tripping device 341 to retain the tripping device 341 in position on the circuit breaker. The part 345 passes through a suitable opening in the housing part 115 of the trip device 15 and the inner end of the part 345 is disposed adjacent the lower side of the trip bar 1119. A compression spring 351 is disposed over the part 345 and it engages the housing part 115 and a spring support 353 to bias the part 345 and therefore the entire tripping device 341 outward to the position wherein the pin 349 engages the barrier 347. An adjusting screw 355 engages the part 345 at one end thereof and threadedly engages the part 343 at the other end thereof to enable adjustment of the length of the tripping device 341 to thereby enable adjustment of the tripping function that will be hereinafter described. As can be seen in FIG. 10, a roller 357 is rotatably supported at the outer end of the part 343 on a pin 359. Another roller 361 is rotatably supported on the pin 359 adjacent the roller 357. Referring to FIG. 7, it will be seen that when the door 221 of the switchboard (FIG. 6) is in the closed position seen in FIG. 7, the door engages the outer end of the cam member 327 biasing the cam member to the right to the position seen in FIG. 7. The spring 351 (FIG. 4) biases the tripping device 341 outward to the position seen in FIG. 7. When the door 221 is moved to the open position,'the cam member 327 is released and the spring 333 (FIG. 9) biases the cam member 327 to the left whereupon the cam part 329 of the member 327 engages the roller 361 (FIG. 10) camming the tripping device 34 1 (FIG. 4) inward against the bias of the spring 351 during which movement the part 345 engages the trip bar 119 to rotate the trip bar to a tripping position to thereby trip the circuit breaker in the same general manner hereinbefore described. Thus, it can be understood that the circuit breaker 3 is automatically tripped by operation of the cam member 327 when the cabinet door 221 is moved to the open position. If for any reason the spring 333 should fail, the circuit breaker would not be tripped by operation of the cam 227 when the door 221 is opened. Means is provided to trip the breaker if an attempt is then made to move the breaker to the disconnected position. As can be seen in FIG. 11, when the circuit breaker structure 300 is moved from the connected position seen in FIG. 7 toward the disconnected position seen in FIG. 11, the roller 357 will engage the stationary cam member 319 moving to the top surface of the cam member 319 which camming action moves the tripping device 341 inward against the bias of the spring 351 (FIG. 4) to effect an automatic tripping operation in the same manner hereinbefore described. The cam member 319 is so positioned that the breaker will be tripped before the terminal connectors 91 are moved to the disconnected position seen in FIG. 11.

It is to be understood that at certain installations only one of the improved tripping cam structures 319 or 327 may be used without the other in a switchboard.

Referring to FIGS. 7, 11 and 13, it will be noted that the circuit interrupter structure 300 will be eflectively retained in the connected and disconnected positions by automatic operation of the manually releasable locking member 279. The slot 291 serves to maintain the circuit interrupting structure 300 in the disconnected position and also to stop the circuit interrupting structure in the disconnected position to prevent accidental displacement off of the tracks 261, of this structure when the structure is being moved out of the connected position.

While the invention has been disclosed in accordance with the provisions of the patent statutesit is to be understood that various changes in the structural details and arrangement of parts may be made without departing from the spirit and scope of the invention.

We claim as our invention:

1. A switchboard structure comprising a cabinet having a cabinet opening therein, bus bar means supported in said cabinet, terminal means electrically connected to said bus bar means, a cricuit interrupting device sup ported in said cabinet and comprising a terminal structure automatically connected to said terminal means by the positioning of said circuit interrupting device in said cabinet, said circuit interrupting device comprising an insulating housing having a first opening therein and a pair of contacts supported within said housing, an operating member extending through said first opening and being manually movable to open and close said contacts, said insulating housing having a second opening therein, a tripping device supported in said insulating housing and extending outward from said second opening, a trip bar supported within said insulating housing and being movable to effect automatic opening of said contact-s, said cabinet comprising a stationary cam member, and upon movement of said circuit interrupting device outward from said cabinet said tripping device engaging said stationary cam member and being cammed to a position to move said trip bar to effect automatic opening of said contacts.

2. A switchboard srtucture comprising a cabinet having a cabinet opening therein, bus bar means supported in said cabinet, terminal means electrically connected to said bus bar means, a circuit interrupting structure supported in said cabinet and comprising a terminal structure automatically connected to said terminal means by the positioning of said circuit interrupting structure in the connected position, said circuit interrupting structure comprising an insulating housing having a first opening therein and a pair of contacts supported within said housing, an operating member extending through said first opening and being manually movable to open and close said contacts, said insulating housing having a second opening therein, a tripping device supported in said insulating housing and extending outward from said second opening, a trip bar supported within said housing and being movable to a tripping position to effect automatic opening of said contacts, said cabinet comprising a stationary cam member, upon movement of said circuit interrupting structure away from said connected position toward a disconnected position wherein said terminal structure is disconnected from said terminal means said tripping device engaging said stationary cam member and being cammed to a position to move said trip bar to said tripping position, and upon movement of said circuit interrupting structure from said disconnected position toward said connected position said tripping device engaging said stationary cam member and being cammed to a position to move said trip bar to said tripping position.

3. A switchboard structure comprising a cabinet having a cabinet opening therein, bus bar means supported in said cabinet, a circuit interrupter supported in said cabinet in a connected position connected to said bus bar means, said circuit interrupter comprising an insulating housing having a first opening means therein and a second opening means therein, a pair of contacts supported in said insulating housing, an operating member supported in said insulating housing and extending out through said first opening means, said operating member being manually operable to open and close said contacts, trip means supported within said insulating housing, said trip means comprising a latched releasable member releasable to effect automatic opening of said contacts and a trip bar movable to efiect release of said latched releasable member, a spring biased movable cam means supported in said cabinet, said circuit interrupter comprising a tripping device supported in said insulating housing and extending out through said opening means, a cover in a closed position closing said cabinet opening and engaging said spring biased movable cam means to maintain said spring biased movable cam means in an inoperative position, and upon opening of said cover said spring biased movable cam means moving automatically to engage said tripping device to move said tripping device to a tripping position, said tripping device in moving to said tripping position moving said trip bar to eliect release of said latched releasable means to eifect opening of said contacts.

4. A switchboard structure according to claim 3, and said tripping device comprising an elongated member supported on said circuit interrupter for rectilinear movement.

5. A switchboard structure comprising a cabinet having a cabinet opening therein, bus bar means supported in said cabinet, terminal means electrically connected to said bus bar means, a circuit interrupter supported in said cabinet and comprising a terminal structure automatically connected to said terminal means when said circuit interrupter is positioned in said cabinet in a connected position, said terminal structure being automatical- 1y disconnected from said terminal means when said circuit interrupter is moved from said connected to a disconnected position toward said cabinet opening, said circuit interrupter comprising an insulating housing having a first opening means therein and a second opening means therein, a pair of contacts supported in said insulating housing, an operating member extending out from said first opening means and being manually movable to open and close said contacts, said circuit interrupter comprising trip means supported within said insulating housing, said trip means comprising a latched releasable member releasable to effect automatic opening of said contacts and a trip bar movable to effect release of said latched releasable member, a tripping device supported in said insulating housing and extending out through said second opening means, said tripping device being movable to a tripping position to move said trip bar to effect release of said latched releasable member to thereby effect automatic opening of said contacts, a cam structure supported on said cabinet and combrising a stationary cam member and a movable cam member, said cabinet comprising a door closing said cabinet opening and movable to an open position to open said cabinet opening, said door in the closed position thereof maintaining said movable cam member in an inoperative position, when said door is moved to the open position with said circuit interrupter in the connected position said movable cam member being automatically released and moving to move said tripping device to said tripping position, said stationary cam member being stationarily positioned such that when said circuit interrupter is moved from the connected position toward the dis connected position said stationary cam member is in the path of movement of said tripping device, whereby when said door is opened and said movable cam member fails to move said tripping device to said tripping position and said circuit interrupter is moved from the connected position toward the disconnected position said tripping device will engage said stationary cam member and be automatically moved to said tripping position.

6. A switchboard structure according to claim 5, and said triping device comprising an elongated member supported on said circuit interrupter for rectilinear movement into and out of said tripping position.

7. A switchboard structure comprising a cabinet having a cabinet opening therein, bus bar means supported in said cabinet, stationary terminal means supported in said cabinet and electrically connected to said bus bar means, track means supported in said cabinet in proximity to said stationary terminal means, a circuit interrupting device supported in said cabinet and comprising support means engaging said track means, said circuit interrupting device comprising a terminal structure, said circuit interrupting device being movable on said track means between a connected position wherein said terminal structure is automatically connected to said terminal means and a disconnected position wherein said terminal structure is automatically disconnected from said terminal means, positioning means operable to move said circuit interrupting device on said track means into and out of said connected position, said circuit interrupting device comprisin an insulating housing having a first opening therein and a pair of contacts supported within said insulating housing, an operating member extending through said first opening and being movable to open and close said contacts, said insulating housing havmg a second opening therein, a tripping device supported in said insulating housing and extending outward from said second opening, a trip bar supported within said insulating housing and being movable to eliect automatic opening of said contacts, a stationary cam member supported on said cabinet in the path of movement of said tripping device which path is determined by the movement of said circuit interrupting device on said track means from said connected position toward said disconnected position, and upon movement of said circuit interrupting device on said track means outward from said cabinet from said connected position to said disconnected position said tripping device engaging said cam member and being cammed automatically to a position to move said trip bar to elfect automatic opening of said contacts before said circuit interrupting device reaches said disconnected position.

8. A switchboard structure according toclaim 7, and said positioning means comprising a bell-crank lever member manually operable to move said circuit interrupting device on said track means into and out of said connected position.

References Cited UNITED STATES PATENTS 2,95 8,858 11/ 1960 Eversole ZOO-61.62 X 3,073,925 1/ 1963 Thomas et al. 20088 3,188,412 6 /1965 Netzel 200'50 3,249,708 5/1966 Johnson ZOO-61.62 X

RROBERT K. SCHAEFER, Primary Examiner.

M. GINSBURG, Assistant Examiner.

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