Abstract:
A molded case circuit breaker is taught with a housing base and a primary cover disposed on the housing base. The primary cover has a recess therein for an auxiliary module which is disposed in the recess. A secondary cover is disposed on the primary cover for covering the recess when the auxiliary module is disposed therein. A combination manual trip and secondary cover interlock is provided which is accessible from outside of the secondary cover for manually opening separable main contacts or for automatically opening separable main contacts when the secondary cover is removed. There is also provided on the back plane of the housing a single piece DIN rail attachment for securing the back plane to a DIN rail. There is provided an under voltage release mechanism for actuating the circuit breaker to trip on the occurrence of an under voltage condition of predetermined magnitude across the lines served by the circuit interrupter. The under voltage release mechanism has an adjustment spring which is controlled by a nut or thumb screw on a shaft to vary the spring force for calibrating the under voltage release mechanism. There is also provided a self-retaining collar member for the load and line terminals of the circuit interrupter. The collar member comprises a locating protrusion in the bottom thereof which aligns with a hole in the load or line conductors. Side entrapment members which entrap the line or load conductor therebetween and between the bottom of the collar member are also provided.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a division of application Ser. No. 08/864,104 filed May 28, 1997 now abandoned. The subject matter for this invention is related to concurrently filed co-pending applications: U.S. patent application Ser. No. 08/864,095 filed May 28, 1997 entitled “Circuit Interrupter With Plasma Arc Acceleration Chamber And Contact Arm Housing”; U.S. patent application Ser. No. 08/864,141 filed May 28, 1997, entitled “Circuit Breaker With Welded Contact Inter-lock, Gas Sealing Cam Rider And Double Rate Spring” and U.S. patent application Ser. No. 08/864,100 filed May 27, 1997 entitled “Combined Wire Lead And Interphase Barrier For Power Switches”, U.S. Pat. No. 5,875,885 Mar. 2, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The subject matter of this invention is related to circuit interrupters generally and more particularly to covered accessory cases therefore, as well as adjustable under voltage relays, wire retainer collars and one-piece rail attachments. 
     2. Description of the Prior Art 
     The present invention provides an improvement over U.S. Pat. No. 4,503,408 issued Mar. 5, 1985 to Mrenna et al entitled “Molded Case Circuit Breaker Apparatus Having Trip Bar With Flexible Armor Interconnection” which is assigned at this time to the assignee of the present application and which is incorporated by reference herein. Accessories for molded case circuit breakers have been known for a long time. Generally in the past the accessories have been mounted externally of the internal portion of the circuit breaker. Molded case circuit breakers are well known in the art. An example of such an accessory is found in U.S. Pat. No. 4,595,812 issued Jun. 17, 1986 to Tamaru et al entitled “Circuit Interrupter With Detachable Optional Accessories”. In some cases the accessories are mounted within the internal portion of the circuit interrupter and are protected from interference or dangerous contact by an accessory cover. Examples of such covers are shown in U.S. Pat. No. 4,754,247 issued Jun. 28, 1988 to P. A. Raymont et al entitled “Molded Case Circuit Breaker Accessory Enclosure”; U.S. Pat. No. 4,757,294 issued Jul. 12, 1988 to Todarol entitled “Combined Trip Unit and Accessory Module for Electronic Trip Circuit Breakers” and U.S. Pat. 4,788,621 issued Nov. 29, 1988 to Russell et al entitled “Molded Case Circuit Breaker Multiple Accessory Unit”. In all of these examples, the covers can not be removed or opened when the circuit breaker contacts are in the closed position, this provides a safety feature. It would be advantageous, however, if means were found to automatically trip a circuit breaker if the cover is opened and where the same device could be used manually simply to trip the circuit breaker upon desire. 
     In Europe, molded case circuit breakers are disposed on mounting apparatus called DIN rails rather than in typical load centers as is the common practice in the United States. Therefore, circuit breakers manufactured for use in Europe must be adapted to be interconnected with the DIN rails. An example of such a separate adapter mechanism may be found in U.S. Pat. 5,192,227 issued Mar. 9, 1993 to Bales entitled “DIN Rail Mounting Bracket”. Usually the aforementioned DIN rail attachments come in multiple pieces which are assembled onto the back of the circuit breaker for snapping onto the DIN rail at a later time. It would be advantageous if a single DIN rail adapter connection device could be found which was part of the circuit breaker casing. 
     Many molded case circuit breakers have under voltage trip release mechanisms for causing the circuit breaker to trip open when the voltage on the lines thereof falls below a predetermined limit. The under voltage release mechanism must be adjustable to accommodate many different ranges of voltages and to account for small manufacturing errors when adapted for the use with a single voltage. It would be advantageous if an under voltage release spring adjustment could be found which would simplify the above indicated problem. 
     Molded case circuit breakers have load and line terminals for interconnection with circuits to be protected or from which power is derived respectively. In order to interconnect the aforementioned terminals with the circuits in question, a collar is provided on the terminal for the interconnection. Such a collar is shown in U.S. Pat. No. 5,206,789 issued Apr. 27, 1993 to Barbry entitled “Terminal Assembly For A Circuit Breaker And Similar Apparatus” assigned on the record to the assignee of the present application. The latter patent is incorporated herein by reference. In order to secure the interconnection between the load conductor for example and the wiring, the wiring and load conductor must be joined by way of the collar. This is a delicate operation requiring the collar to be held precisely in place as the joint is completed. It would be advantageous if a collar arrangement could be found which was self-retaining, that is which was disposed upon the line or load conductor of the circuit breaker in such a manner as to not require separate activity during the connecting operation. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, an electrical circuit interrupter is taught which includes a housing base and a primary cover disposed thereon where the primary cover has a recess therein for an auxiliary module. A secondary cover is disposed on the primary cover for covering the recess. An operating mechanism containing first and second separable main contacts is disposed within the housing. A combination manual trip and secondary cover interlock which is accessible from outside of the secondary cover is provided for either manually opening the separable main contacts or for automatically opening the separable main contacts when the cover is opened. 
     The circuit interrupter has a trip means interconnected for opening the separable main contacts upon actuation. An under voltage release mechanism is disposed within a housing in a disposition of structural cooperation with the operating mechanism for actuating the trip device on the occurrence of an under voltage of predetermined magnitude on a circuit which is interconnected with the separable main contacts. The under voltage release mechanism comprises a spring loaded plunger which is held in a first disposition when the voltage is greater than the predetermined magnitude but which actuates under the influence of the spring when the voltage is substantially equal to or less than that predetermined magnitude. The adjustment of the spring is controlled by a threaded nut or thumb wheel on a shaft which abuts against one end of the spring for changing the spring force to vary the predetermined magnitude. 
     A collar for an electrical circuit interrupter is taught which is utilized for interconnecting a conductor of the circuit interrupter with an external electrical conductor. The collar includes a bottom portion and side portions forming an enclosure. Transverse trap means are disposed internally of the enclosure on the side portions for capturing the rectangular cross-sectional conductor therebetween and the bottom portion. The bottom portion has a locating protrusion thereon which aligns with a hole in the conductor of the circuit breaker for fixing the disposition of the collar on that conductor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows an orthogonal view of a molded case circuit breaker embodying the teachings of the present invention; 
     FIG. 2 shows an exploded view of the housing, primary cover and secondary cover of the circuit breaker of FIG. 1; 
     FIG. 2A shows an orthogonal view partially broken away of the combination push-to-trip and auxiliary cover interlock member; 
     FIG. 3 shows a side elevation of an internal portion of the circuit breaker of FIG. 1; 
     FIG. 4 shows an orthogonal view of the operating mechanism, movable contact arrangement, shunt trip device and contact support member of the circuit breaker of FIG. 1; 
     FIG. 5 shows an orthogonal view of a portion of the circuit interrupter shown in FIG. 1 in which the primary cover and secondary cover have been removed; 
     FIG. 6 shows a side elevation partially broken away of the operating mechanism of the circuit breaker of FIG. 1 with the contacts and handle in the OPEN state; 
     FIG. 7 shows an arrangement similar to FIG. 6 but with the contacts and handle in the ON state; 
     FIG. 8 shows an arrangement similar to FIG. 6 but with the contacts and handle in the TRIPPED state; 
     FIG. 9 is similar to FIG. 6 but with the contacts open and the handle momentarily moved to the RESET state; 
     FIG. 10 shows a side elevation partially broken away of the rotating crossbar, handle mechanism and anti-weld interlock of the circuit interrupter of FIG. 1; 
     FIG. 11 shows an orthogonal view of a cam rider; 
     FIG. 12 shows a portion of the crossbar arrangement into which the cam rider is disposed; 
     FIG. 13 shows a side elevation partially broken away of the crossbar and cam rider of FIGS. 11 and 12 operating in conjunction with the movable contact as disposed in the blown-open state; 
     FIG. 14 shows a side elevation partially broken away of the trip mechanism of the circuit interrupter of FIG. 1; 
     FIG. 15 shows an orthogonal view of the lower contact support member and housing including the arc runner of the circuit interrupter of FIG. 1; 
     FIG. 16A shows a side view of the upper slot motor housing of the circuit interrupter of FIG. 1; 
     FIG. 16B shows a front view of the housing of FIG. 16A; 
     FIG. 16C shows an orthogonal view of the housing of FIGS. 16A and 16B; 
     FIG. 17 shows an exploded, side elevation, partially broken away orthogonal view of the mounting arrangement for the LINE conductor for the circuit interrupter of FIG. 1; 
     FIG. 18 shows an orthogonal view partially broken away of the auxiliary switching arrangement for the circuit interrupter shown in FIG. 1; 
     FIG. 18A shows an orthogonal view of one section of the auxiliary switch module shown in FIG. 18; 
     FIG. 18B shows an orthogonal view of the complimentary section of the switch module shown in FIG.  18 . 
     FIG. 19A shows a front elevation of the circuit interrupter of FIG. 1 depicting the under voltage relay arrangement; 
     FIG. 19B shows an enlarged view of the under voltage release mechanism of FIG. 19A; 
     FIG. 19C shows an orthogonal view of the under voltage release mechanism of FIGS. 19A AND 19B; 
     FIG. 20 shows an orthogonal view of the circuit interrupter similar to that shown in FIG. 1 but with interphase wire trough barriers in place; 
     FIG. 21A shows a partially broken away orthogonal view of the circuit breaker of FIG. 1 from the back; 
     FIG. 21B shows a partially broken away orthogonal view of the circuit breaker of FIG. 1 from the back so as to depict the DIN rail attachment region; 
     FIG. 22A shows an orthogonal view of a load or line terminal collar embodied in the present invention; and 
     FIG. 22B shows an orthogonal view of the collar of FIG. 22A disposed upon a line conductor. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings and FIGS. 1 and 2 in particular, there is shown a molded case circuit breaker  10 . Molded case circuit breaker  10  includes a lower base portion  14  mechanically interconnected with a primary cover  18 . Disposed on top of the primary cover  18  is an auxiliary or secondary cover  22 . The secondary cover  22  may include slightly depressed regions  22 A therein into which nameplates for the circuit breaker  10  may be disposed. There is also provided on the right an opening  22 B for a combination push-to-trip interlock member as will be described hereinafter. The secondary cover  22  may be removed from the circuit breaker rendering some internal portions of the circuit breaker available for maintenance and the like without disassembling the entire circuit breaker. In particular, the secondary cover  22  may shield auxiliary devices such as under-voltage relays, bell alarms and auxiliary switches, for example, which will be described hereinafter. Holes or openings  26  are provided in the secondary cover  22  for accepting screws for fastening the auxiliary or secondary cover  22  to the primary cover  18 . Additional holes  30  which feed through the auxiliary cover  22 , the primary cover  18  and the base  14  are provided for bolting the entire circuit breaker assembly onto a wall, into a DIN rail back panel or into a load center or the like. The auxiliary cover  22  includes an auxiliary cover handle opening  34 . The primary or main cover  18  includes a primary cover handle opening  38 . There is provided a handle  42  which protrudes through the aforementioned auxiliary cover handle opening  34  and the primary cover handle opening  38 . The handle  42  is utilized in the normal manner to open and close the contacts of the circuit breaker manually and to reset the circuit breaker when it has been tripped. It may also be provided as an indication of the status of the circuit breaker, that is whether the circuit breaker is ON, OFF or TRIPPED. There is also shown in base  14  an elongated circular groove  22 C for capturing the combination push-to-trip interlock member in a manner which will be described more fully hereinafter. Protruding upwardly through the rectangular opening  22 B is a top portion  23 A of the aforementioned combination push-to-trip interlock member the details of which will be more fully explained hereinafter. There are also shown three load conductor openings  46  which shield and protect load terminals  50  (not shown). The circuit breaker depicted is a three-phase circuit breaker. However, the invention is not limited to three-phase operation. Not depicted in FIGS. 1 and 2 are the LINE terminals which will be described hereinafter. 
     Referring now to FIG. 2A there is shown a broken away orthogonal view of the circuit breaker  10  in the region of the base  14  with the combination push-to-trip and secondary cover interlock member  23  in place. In particular, member  23  includes a rectangular push-button top portion  23 A which was described with respect to FIG.  2 . There is also provided an extended circular guide member  23 B which is connected in interlocking disposition with the aforementioned groove  22 C such that member  23  may move upwardly or downwardly in the directions  23 H and  23 K, but may not rotate or move otherwise. On a lower part of the member  23  is a first push-to-trip tab portion  23 C and oppositely dispose thereof, on the other side of member  23 A is an angularly offset pull-to-trip tab member  23 D. Provided rear the top of the member  23  is a set of shoulders  23 E which separate the main body of the combination member  23  from its push-to-trip region  23 A. The shoulders  23 E abut upwardly against the bottom surface of the secondary cover  22  to prevent further linear motion in the upward direction. The middle bottom portion of the member  23 B is designated  23 F and it provides a seat for a compression spring (not shown) which biases the member  23  in the direction  23 H. A rotatable trip shaft  200  is shown which will be described in further detail hereinafter. For the purposes of this portion of the invention it is sufficient to say that the trip shaft  200  is biased rotationally by a torsion spring in the rotational direction opposite to that shown at  200 C. Rotation of the member  200  in the direction  200 C will cause a tripping of the circuit breaker in a manner to be described hereinafter. The combination member  23  provides the aforementioned rotation  200 C in either of two manners. If the push-to-trip surface  23 A is actuated downwardly in the direction,  23 K push-to-trip tab member  23 J will impinge upon tab member  200 B which is rigidly attached to the rotating shaft  200  in such a member as to rotate the shaft  200  in the direction  200 C and cause a tripping action of the circuit breaker. On the other hand, if the secondary cover  22  is remove the shoulder  23 E has nothing to abut upwards against under the influence of the compression spring acting on portion  23 F which causes the member  23  to be forced upwardly in the direction  23 H by the action of the compression spring thus causing the secondary cover interlock tab  23 D to strike upwardly against tab member  200 A on the shaft  200  thus forcing the shaft  200  to rotate in the direction  200 C thus causing the circuit breaker to trip. Consequently it can be seen that the same member  23  may be utilized to trip the circuit breaker by interaction thereof with the shaft  200  either by downward motion in the direction  23 K when a push-to-trip actuation is required or by upward motion in the direction  23 H if the secondary cover is removed. 
     Referring now to FIG. 3, a longitudinal section of a side elevation, partially broken away and partially in phantom of the circuit breaker  10  is depicted. In this depiction, certain key features of the circuit breaker are shown. It is to be understood that many of these features will also be described in greater detail hereinafter. There is shown a plasma arc acceleration chamber comprising a slot motor assembly  54  and an arc extinguisher assembly  58 . There is also shown a contact assembly  56  comprising a movable contact arm  58  supporting thereon a movable contact  62  and a stationary contact arm  68  supporting thereon a stationary contact  64 . An operating mechanism  63  is also depicted. The operating mechanism  63  will be described in further detail hereinafter. The operating mechanism  63  is similar to and operates similarly to that shown and described in U.S. Pat. No. 4,503,408 issued Mar. 5, 1985, to Mrenna et al, which patent is herein incorporated by reference. There is also shown a trip mechanism  67  which in this non-limiting embodiment of the invention is an electromagnetic trip mechanism. It is to be understood that in other embodiments of the invention a thermal trip mechanism may be utilized or a combination of a thermal trip mechanism and an electro-magnetic trip mechanism may be utilized. 
     The slot motor assembly  54  includes a separate upper slot motor assembly  54 A and a separate lower slot motor assembly  54 B. The upper slot motor assembly  54 A includes stacked side-by-side U-shaped upper slot motor assembly plates  74  which are composed of magnetic material. In a like manner lower slot motor assembly plates  78  are disposed in the lower slot motor assembly  54 B. Lower assembly plates  78  are also composed of magnetic material. The combination of the upper slot motor assembly plates and the lower slot motor assembly plates  74  and  78  respectively, form an essentially closed electromagnetic path which provides the slot motor function which is shown and described in U.S. Pat. No. 3,815,059 issued Jun. 4, 1974 to Spoelman and entitled “Circuit Interrupter Comprising Electro-Magnetic Opening Means.” 
     The arc chute assembly  58  includes an arc chute  80  having spaced apart generally parallel angularly off-set arc chute plates  84  and an upper arc runner  84 A. There is also provided a lower runner  88  which is not part of the arc chute  80 . There is also provided a line terminal  71 . 
     Referring to FIG.  4  and FIG. 13, an orthogonal view of an internal portion of the circuit breaker  10  is shown. In particular, there is shown a crossbar assembly  100  which traverses the width of the circuit breaker and which is rotatably disposed on an internal portion of the base  14  (not shown). Movement of a lower toggle link  144 , in a manner which will be described hereinafter, causes the crossbar  100  and the associated movable contact arms  58  to rotate into or out of a disposition which places movable contacts  62  into or out of a disposition of electrical continuity with fixed contacts  64 . Each movable contact arm  58  is rotatably disposed upon a pivot pin  104  which is disposed in the movable contact cam housing  102 . There is one movable contact cam housing  102  for each movable contact arm  58 . Disposed in the movable contact cam housing is a cam follower  110  which is spring loaded by way of a spring  112  (see FIG. 13) in the upward direction against the movable cam  110  (see FIG.  13 ). During assembly, the cam follower  110  is inserted into the cam follower opening  114  in the housing  102  in a longitudinal direction and then raised upwardly against the cam  110 . The spring  112  is interposed between the upside of the bottom of the housing  102  and the bottom of the cam follower  110  thus urging the cam follower  110  against the bottom surface or camming surface  106  of the contact arm  58 . It is to be noted with respect to the crossbar assembly  100  that the movable contact arm  58  is free to rotate within limits independently of the rotation of the crossbar assembly  100 . In certain dynamic, electro-magnetic situations, the movable contact arm  58  can rotate upwardly about the movable contact pivot pin  104  under the influence of high magnetic forces whereupon it is latched in that disposition by the action of the rear most surface or latching surface of the movable contact arm  58  and the cam follower  110 . Under normal circumstances however, the movable contact arm  58  rotates in unison with the rotation of the housing  102  as housing  102  is rotated clockwise or counter-clockwise by the action of the lower link pin  144 . Also depicted in FIG. 4 is a portion of a self-contained auxiliary switch and alarm lock  320  which will be described in greater detail with reference to FIG.  5 . 
     Continuing to refer to FIG.  4  and also referring to FIG. 6, the operating mechanism  63  is depicted and described. The operating mechanism  63  comprises a handle assembly  126 , a cradle assembly  130 , an upper toggle link  140 , an interlinked lower toggle link  144 , and an upper toggle link pivot pin  148  which interlinks the upper toggle link  140  with the cradle assembly  130 . The lower toggle link  144  is pivotally interconnected with the upper toggle link  140  by way of the intermediate toggle link pivot pin  156 . There is provided a cradle assembly pin  160  which is laterally disposed between parallel, spaced apart operating mechanism support members  161 . Cradle assembly  130  is free to rotate within limits about cradle assembly pivot pin  160 . There is provided a handle assembly roller  164  which is disposed in and supported by the handle assembly  126  in such a manner as to make mechanical contact with a portion of the cradle assembly  130  during certain operations of the circuit breakers as will be described hereinafter. There is also provided a main stop bar  168  which is also laterally disposed between the operating support members  161 . Stop bar  168  abuts and stops or prevents further clockwise movement of the movable contact arm  58  during a circuit breaker opening operation. 
     Continuing to refer to FIG.  4  and referring once again to FIG. 3, the line terminal  71  and associated lower slot motor assembly and fixed contact support member  246  is shown. The fixed contact arm  68 , the fixed contact  64 , the arc runner  88  and the lower slot motor assembly  54 B all comprise portions of the lower slot motor assembly and fixed contact support member  246 . 
     Continuing to refer to FIG. 4 there is also depicted a portion of the trip mechanism  66  and a shunt trip device  92 . The shunt trip  92  comprises: a shunt trip coil  92 A which is normally non-energized, a spring loaded plunger  92 B which is spring-loaded to the off or left disposition by the spring  92 C in a normal condition, a spring-loaded plunger  92 E which is spring-loaded towards the crossbar arrangement  100  and a microswitch  92 D. The microswitch  92 D may be interconnected to a control facility by way of electrical lines  320 C 1  and  320 C 2 . If a control signal is provided on the lines  320 C 1  and  320 C 2 , the coil  92 A is energized thus causing the plunger  92 B to move to the right against the force of the spring  92 C to cause the trip mechanism  66  to trip in a manner to be described hereinafter. Once a tripping action has occurred, the crossbar arrangement  100  rotates upwardly or in the clockwise direction to the right thus causing the spring loaded plunger  92 E to move upwardly thus opening the contacts of the switch  92 D to prevent energy from being supplied to the coil which may have a tendency to burn it out. After the signal has been removed from the lines  320 C 1  and  320 C 2 , the spring  92 C causes the plunger  92 B to move to the left as shown in FIG. 4 for further action at a later time. The case for the shunt trip  92  is of the molded variety. It can be dropped into the previously described opening  18 X to thus be covered by the secondary cover  22  in a manner described previously. The drop-in case for the shunt trip  92  comprises two snap together sides  92 G and  92 J which may be joined together by way of flexible snap in hook arrangements  92 F in case portion  92 G which in turn interconnects within opening  92 H in case portion  92 J. In another embodiment of the invention as will be describe hereinafter, the shunt trip arrangement  92  may be replaced by an under voltage module which will be described in greater detail with respect to FIGS. 19A, B and C. 
     Referring now to FIG.  5  and FIG. 3 an orthogonal view of the lower base  14  with the upper cover  18  (FIG. 5) removed and some of the internal portions of the circuit breaker apparatus  10  disposed in place is shown. In particular, in FIG. 5 the under voltage relay  92  and shunt trip device are shown disposed in place having part of their collective protective cover broken away. Also shown is the self-contained auxiliary switch  320 , alarm  324  (see FIG. 18) and associated wiring  320 C. The load conductor openings  46  are shown on the right and the panel mounting holes  30 B in the base are shown to the left. Also shown is the plasma arc acceleration chamber  52  comprising the slot motor assembly  54  on the right and the arc extinguisher  58  on the left. The upper slot motor assembly  54 A includes stacked or layered, upper slot motor assembly plates  74  sandwiched between a front plate  292  and rear plate  296  of the upper slot motor assembly housing  291  which in turn comprises a portion of the upper slot motor assembly  54 A. Shown to the left of the slot motor assembly  54  is the arc chute  80  assembly or arc extinguisher  58 . The arc chute  80  comprises spaced, generally parallel, angularly slanted arc chute plates  84  of which the upper arc runner  84 A is most prominently shown. 
     Referring once again to FIG. 6, an elevation of that part of the circuit breaker  10  particularly associated with the operating mechanism  63  is depicted. The contacts  62  and  64  are shown in the disconnected or open disposition of the circuit breaker operating mechanism  63 . Stop bar  168  is shown in a disposition sufficient to prevent movable contact arm  58  from rotating significantly further upwardly in a clockwise direction. Cradle assembly pivot pin  160  supports cradle assembly  130  in such a manner that handle assembly roller  164  abuts against a back portion  165  of the cradle assembly  130 . In certain operations of the operating mechanism  63 , roller pin  164  rolls against arcuate portions of region  165  for the purpose of moving or rotating the cradle assembly  130  about cradle assembly pivot pin  160  in a clockwise direction for the purpose of resetting the circuit breaker in a manner which will be described hereinafter. In the disposition shown in FIG. 6, intermediate latch  176  is shown in its latched position abutting hard against the lower portion  139  of the latch region  131  of the cradle assembly latch cutout  135 . A pair of side-by-side aligned compression springs (not shown) such is shown in U.S. Pat. No. 4,503,408 is disposed in the operating mechanism  63  between the top portion of the handle assembly  126  and the knee or intermediate toggle link pivot point  156 . The tension in the aforementioned springs has a tendency to load portion  139  against the intermediate latch  176 . Latch  176  is prevented from unlatching the cradle assembly  130  because the other end thereof is fixed in place by the trip bar assembly  200  which is spring biased in the counter-clockwise direction against the intermediate latch  176 . This is the standard latch arrangement found in all dispositions of the circuit breaker except the unlatched disposition which will be described hereinafter. 
     In the disposition shown in FIG. 6, positive off-link  188  which is biased against rotation in the clockwise direction abuts against the circular portion of the crossbar  100  in such a manner that the fixedly attached positive off-link upper portion  189  is in a disposition of clearance away from the handle assembly cutout  137  so that movement in the clockwise rotational direction of the handle assembly  126  will be in such a manner that the cutout  137  misses or clears the aforementioned positive off-link upper portion  189 . 
     If, on the other hand, an operation tending to open the circuit breaker contacts resulting in a movement of the handle mechanism  42  in the clockwise direction to the right as will be shown and described in greater detail with respect to FIG. 10, will not cause the contacts  62  and  64  to separate such as when they are in a welded-closed disposition, the crossbar positive off protrusion  101  will force the positive off-link  192  to rotate in the counter-clockwise direction to the left. This causes handle assembly cutout  137  to abut against the positive off-link upper portion  189  thus preventing further movement of the handle in the clockwise direction to the right. This clearly indicates that the contacts have not opened even though an opening operation has been attempted. 
     Referring now to FIG. 7, the arrangement of the operating mechanism  63  is shown for the circuit breaker in the CLOSED disposition. In this disposition an electrical current may flow from load terminal  50  to line terminal  71  through the closed contacts  62  and  64  of the circuit breaker. The handle  42  has been rotated in a counter-clockwise direction to the left thus causing fixedly attached handle assembly  126  to rotate to the left or in a counter-clockwise direction thus causing the intermediate toggle link pivot point  156  to be influenced by the tension springs attached thereto (not shown) and to the top of the handle mechanism  126  to cause the upper and lower toggle links  140  and  144  respectively to assume the position shown in FIG.  7 . The assumption of the aforementioned position causes the pivotal interconnection with the crossbar  100  at pivot point  142  to rotate the crossbar  100  in the counterclockwise direction in such a manner as to cause arm  58  to force contact  62  into a pressurized abutted disposition with contact  64 . In comparing the arrangement of the elements of the operating mechanism  63  between FIGS. 6 and 7, the following elements remain unchanged in disposition: The cradle assembly  130  remains latched by the intermediate latch  176  as influenced by the trip assembly  200 . In addition since the movable contact arm  58  has been rotated into a disposition to close or abut the contacts  62  and  64  the cross bar positive-off protrusion  101  has made contact with the positive-off link  188  rotating it against its bias torsion spring in a counter-clockwise direction for being in a disposition to intercept the handle assembly cutout  137  in the event there occurs an operation tending to move the handle  42  and the associated handle assembly  26  to the right in a clockwise direction in an opening or tripping operation while the contacts  62 ,  64  remained closed. The following elements have attained a different orientation in FIG. 7 relative to FIG.  6 : The handle assembly  126  has been rotated counter-clockwise to the left thus causing upper toggle link  140  and lower toggle link  144  to be influenced by the spring (not shown) attached to intermediate toggle link pivot pin  156  to cause rotation of the crossbar assembly  100  at the pivotal interconnection  142  with the crossbar thus causing the contact carrying arm  58  to move in a counterclockwise direction to cause contact  62  to forcibly abut contact  64  to form a closed circuit between load conductor  50  and line conductor  71 . 
     In the arrangement depicted in FIG. 6 the handle  42  has been rotated to the right to a rotational position indicative of the contacts being OPEN. The handle position corresponds with a legend on the auxiliary cover  22  which clearly indicates the status of the circuit breaker contacts as being OPEN. Correspondingly, in the representation depicted in FIG. 7 where the contacts  62  and  64  are closed, the handle has been rotated to the left or counter-clockwise to a rotational disposition indicated by a legend on the auxiliary cover  22  of the contacts being CLOSED. 
     Referring now to FIG. 8, the TRIPPED disposition of the operating mechanism  63  is depicted. In particular, the TRIP disposition is related to an automatic or magnetically induced disposition of the circuit breaker in which the circuit breaker automatically opens in response to electro-magnetic or other stimulus related to the magnitude of the current flowing between the line conductor  71  and the load conductor  50 . In particular, a solenoid assembly  97  is provided which is interposed electrically between the load conductor  50  and the movable contact arm  58  and is thus exposed to the full electrical current flowing through the electrical contacts  62  and  64  when they are closed. In the event that that load current exceeds a predetermined amount, the solenoid  97  interacts by way of an electro-magnetically controlled plunger (not shown herein for purposes of simplicity of illustration) to induce the trip bar assembly solenoid armature interface  208  to move downwardly, in response to the electromagnetic action of the solenoid assembly  97 , in a clockwise direction about a trip bar assembly pivot  204  to cause the attached trip bar assembly intermediate latch interface  212  to rotate correspondingly away from the intermediate latch  176  thus freeing the cradle assembly  130  which had been held in place at the latch region  131  in the cradle assembly latch cutout  135  to be rotated counter-clockwise under the influence of the tension springs (not shown) interacting between the top of the handle mechanism  126  and the intermediate toggle link pivot pin  156 . This collapses the later toggle arrangement. This in turn causes the pivotal interconnection  142  to be rotated clockwise and upwardly to thus cause the crossbar  100  to rotate in a similar manner thus causing contacts  62  and  64  to be separated by the clockwise motion of the movable contact arm  58 . In this disposition the cradle assembly  130  has been rotated to the left or in a counter-clockwise direction about its axis  160 , thus causing the cradle member arcuate surface  177  to ride against the upper arm of the intermediate latch  176  thus keeping the lower arm thereof free from interconnection with the trip bar assembly intermediate latch interface  212  even thought that interface may have been moved back into the latching disposition by the cessation of the high current flowing in the solenoid assembly  97 . In this disposition, the handle  42  is maintained in an intermediate disposition between its disposition in the CLOSED state as shown in FIG.  7  and the OPEN state as shown in FIG.  6 . This disposition between the full off and full on positions is depicted on the secondary cover  22  of the circuit breaker  10  as an indication that the circuit breaker is in the TRIPPED state. Once in this disposition the circuit breaker may not be turned on again until it is RESET as will be described hereinafter. After that the handle  42  may be rotated in the counter-clockwise direction to the ON state depicted in FIG. 7 for causing the contacts  62  and  64  to close once again and abut each other in the arrangement of the operating mechanism  63  depicted in FIG.  7 . 
     Referring now to FIG. 9, the disposition of the operating mechanism  63  during resetting operation is depicted. This occurs while the contacts  62  and  64  remain open and is exemplified by a forceful movement of the contact handle  42  to the right or in clockwise direction after a tripping operation has occurred as described with respect to FIG.  8 . The forceful movement of the arm  42  to the right or towards the OPEN indication on the secondary cover  22  (not shown) of the circuit breaker causes fixedly attached handle assembly  126  to move correspondingly. The handle assembly roller  164  makes contact with the back portion  165  of the cradle assembly  130  thus forcing it to rotate clockwise against the tension of the springs (not shown) located between the top of the handle mechanism  126  and the intermediate toggle link pivot point  156  until the upper portion  139  of the cradle assembly latch cut-out  135  abuts against the upper arm of the intermediate latch  176  forcing that intermediate latch to rotate to the left or counter-clockwise so that the bottom portion thereof, also rotates counter-clockwise to the right to a disposition of interlatching with the trip bar assembly intermediate latch interface  212 . Thus when the force against the handle  42  is released it rotates backwardly over a small angular increment in the counter-clockwise direction thus causing the latch region of the cradle assembly to forcefully abut against the intermediate link  176  which is now abutted at its lower end thereof against the trip bar assembly intermediate latch  212  and is kept in that position by the influence of the previously described spring. In this disposition, the circuit breaker handle  42  may then be moved counter-clockwise or to the left towards the on disposition depicted in FIG. 7 without the latching arrangement being disturbed until the contact  62  and  64  are rotated by way of the movable contact arm  58  into a disposition of forceful electrical contact with each other. Once this occurs, a tripping operation such as depicted and described with respect to FIG. 8 may take place causing the contacts to open once again. 
     Under certain circumstances associated with the tripping action shown and described within respect to FIG. 8, the moveable contact arm  58  may independently pivot about its pivot  142  under the influence of extremely high current by way of well understood magnetic action causing the contacts  62  and  64  to separate in a period of time faster than can normally occur as the result of the action of the solenoid assembly  97  as was described previously. This operation will be further described with respect to FIGS. 3,  5 ,  16 A and  16 B where the blow open arrangement of the circuit breaker is described in greater detail. 
     Referring now to FIG. 10, a portion of the operating mechanism  63  broken away from other portions of the circuit breaker  10  as well as portions of the movable and stationary contacts  62  and  64  and the associated supports therefore are shown. In FIG. 10 the contacts are shown in the closed state with moveable contact arm  58  causing movable contact  62  to abut against stationary contact  64  as disposed on stationary contact support arm  68 . A portion of the separation wall  69  between the operating mechanisms  63  and the arcing chamber to the left is shown. The separation wall  69 , in addition to providing physical structure for the circuit breaker, also provides a barrier wall to assist in preventing hot gases from the arcing area on the left from escaping rightwardly towards the operating mechanism  63  on the right. The height of the separation wall  69  is limited by the need for the contact arm  58  to protrude from the region of the operating mechanism  63  to the region of the contact  64 . In the depicted disposition the contacts remain closed but the handle mechanism  126  has been pivotally rotated to the right as in a opening operation or a tripping operation. In this state an indication must be provided for indicating to an observer that the contacts have not opened, even though it may appear that an opening operation has occurred. In particular, cross bar  100  which has a cross bar positive operating protrusion  101  disposed thereon abuts against positive off-link  188  which is in turn rotated counter-clockwise thereby about its rotational axis  192 . This thrusts the positive off-link extension  1890  into the path of the handle assembly cutout  137 . This prevents the handle mechanism  126  which is pivotally supported at  128  by an internal handle support member  127  from rotating any further about its pivot point to the right or in a clockwise direction. This prevents the handle  42  from indicating that the circuit breaker is OFF when in fact it is not. In this contact-welded closed disposition, clear indication is thereby given to operating personnel that the circuit breaker contacts are closed and therefore care must be exercised in servicing or otherwise working with the line or load devices interconnected with the circuit breaker. 
     Referring now to FIGS. 11,  12  and  13 , there is shown a cam follower, crossbar, cam housing arrangement and movable contact disposed in the blown open disposition. The cam follower  110  comprises a main body  111  having on the rear thereof two oppositely disposed transversely protruding cam follower rear tabs  113 . Correspondingly in the front thereof there are two transversely protruding oppositely disposed cam follower front tabs  115 . On the top of the main body  111  is provided a cam follower top rear cam surface  121  and on the front thereof is provided a cam follower top front cam surface  121 A. The cam follower housing  102  disposed on the crossbar assembly  100  includes a cam follower opening  114  having on the inside thereof an inside wall and a pair of oppositely disposed parallel inside wall guides  117  disposed upwardly along the housing  102 . Disposed below the aforementioned guide walls  117  are oppositely disposed, parallel, longitudinally extended inside wall grooves  118 . When assembling the cam follower  110  into the cam follower housing  102 , the tabs  113  are aligned in the grooves  118  in the front of the housing  102  and then pushed inwardly towards the rear. This movement continues until the rearwardly protruding facing surfaces  115 A align with the front of the housing body  102 . At this point the rear tabs  113  have cleared the rear most portion of the groove  118 . At this point the cam follower  110  is raised so that the frontwardly facing surfaces  113 A and the rearwardly facing surfaces  115 A may slide respectively against the rearward and frontward facing walls formed transversely of the side walls  117 . Thereafter spring  112  is disposed between the top of the bottom most portion of the housing  102  and the lower inner surface of the cam  110  against which it is seated. The pressure of the spring  112  maintains the tabular members  115  and  113  clear of the grooves  118  and against the front and rear portions of the walls  117  respectively, thus restraining movement of the cam follower  110  in the housing  102  to upward and downward. As best seen in FIG. 13, when a magnetic blow-open condition occurs as was described previously, contact support arm  58  immediately forcefully rotates about its pivot  104  in a clockwise direction thus bringing attached contact  62  with it, thus separating contacts  62  and  64  (not shown). The contact arm rotational motion is prevented from continuing in the clock-wise direction by the main stop bar  168  (not shown). Since the cross bar assembly  100  has not begun to react to the circuit breaker magnetic trip opening action it remains in place rotationally on its axis  105 . However, the rotation of the movable contact arm  58  causes the rearwardly extending movable contact cam surface  106  thereof to move away from the cam follower top rear surface  121  towards the cam follower top front cam surface  121 A whereupon it depresses the cam follower  110  against the spring  112  thus moving the cam follower down the walls  117  to a disposition where the front of the cam tends to close off a significant portion of the front of the cam follower housing opening  114  thus protecting the spring member  112  from hot gas  149  which is forcefully blown over the wall  69  towards the region of the cam follower  110  and spring  112  during current interruption. 
     Referring now to FIG. 14, a partially broken away, sectional view of the trip mechanism of one embodiment of the invention is depicted. In particular, there is shown the trip bar assembly  200  which includes as part thereof the trip bar assembly intermediate latch interface  212  protruding upwardly and the trip bar assembly solenoid armature interface  208  protruding to the right. Trip bar assembly  200  is disposed to rotate against a bias torsion spring (not shown) around trip bar assembly pivot  204 . The bias spring biases the trip bar assembly in the counter-clockwise direction. As was described previously there is disposed below assembly  200  a solenoid coil  216  which is interconnected with load terminal  50  and by way of a braid or flexible conductor  51  with the rear most portion of the movable contact arm  58 . A solenoid armature guide  221  is in place for capturing therein and guiding therein in a direction longitudinal of the solenoid coil  216  a movable core  224 . The upper end of the movable core  224  is interconnected with a magnetic trip upper assembly  214 . The movable core  224  has disposed thereon a movable core plunger  231 . There is also provided a multi-rate or multi-pitch magnetic trip spring assembly lifter  238 , the bottom of which comprises a spring seat  239  and the top of which is vertically disposable as a function of the trip adjustment cam mechanism  67 . An upper interface seat  234  is provided. The multi-rate magnetic trip spring  220  is disposed around the movable core  224  between the fixed spring seat  239  on the top and the movable multi-rate magnetic trip spring seat  230  on the bottom. Adjustment of the cam  67  causes the movable spring seat  230  on the bottom to transpose axially, thus changing the air gap  246  without affecting the length of the spring  220 . There is provided on the bottom of the core  216  in the channel of the solenoid armature guide  221  a stationary core  242 . Electrical current flowing between the line terminal  50  and the conductive braid  51  causes the coil  216  to induce a magnetic field in the air gap  243  between the stationary core  242  and the movable armature or core  224 . The strength of the magnetic flux or magnetic force in the air gap  243  is a function of the amount of current flowing in the coil  216  and the size of the air gap  243 . This force has a tendency to draw the movable core  224  towards the stationary core  242  to reduce the size of the air gap  246  and is resisted by the multi-rate magnetic trip spring  220 . As the movable core  224  move towards the stationary core  242 , the plunger  230  causes the trip bar assembly solenoid armature interface  208  to move downwardly causing the trip bar assembly  200  to rotate about its pivot point  204  in a clock-wise direction against the force of its torsion spring. This causes the rigidly attached trip bar assembly intermediate latch interface  212  to move away from the intermediate latch  176  in the manner described previously to allow the latch to be freed. This causes the circuit breaker mechanism to trip in the manner described previously. Adjustment of the cam  67  causes the air gap  243  to change. The spring  220  is formed with a multiple winding pitch with more windings per unit axial length at the bottom thereof and less windings per unit axial length at the top thereof. However, other winding arrangements may be used to accomplish the same purpose using different spring factors: continuous movable spring pitch, different spring wire diameters, different spring materials. Thus the magnetic force induced in the solenoid coil by current flowing through the solenoid will cause the plunger  224  to move down slowly at first until all of the tightly wound spring pitch members have been compressed after which the coil will move more quickly as the more loosely wound spring coil pitch members are utilized to resist the movement of the core. This allows for a wider range of trip adjustment which may be, for example, from three times full rated current to eleven time full rated current. The exact adjustment of the tripping point is determined at least in part by the orientation of the cam member  67 . 
     Referring now to FIG.  3  and FIG. 15, the lower slot motor assembly and fixed contact support member  246  is depicted. Member  246  has a lower slot motor assembly arc plate opening  250  into which the lower arc plates  78  are disposed in a side-by-side layered relationship. These magnetic members form the lower part of the completed circuit of the magnetic slot motor  54  as described previously. Element  254  is disposed on and forms part of the right most portion of the lower slot motor assembly and fixed contact support member  246 . It comprises a curvilinear member having a central opening or hollow recess  256  and a curved main contact support member surface  260 . There is also provided a main contact support upper region  264 . The aforementioned lower arc plate opening  250  and its surrounding housing member as well as the main contact support  254  and the main contact support upper region  264  are formed integrally of a single piece of material which may, for example, be molded material having high electrical insulating characteristics and strong structural characteristics. The main contact support upper region  264  has a lower concave surface  268  and main contact support upper region  286 . The main contact support upper region  286  also has a peninsula  272  extending therefrom upon which the movable contact arm  58  (not shown) rests in the close contact disposition thereof. Arc runner  88  is shown disposed along the upper surface  282  of the housing  246 . It is captured between a pair of upper contact support protrusions  280  which are integrally molded into the aforementioned housing  246 . By referring also to FIG. 3, it can be seen that the fixed contact arm  68  comprises a U-shaped member interconnected with the line terminal  71  on one end and the fixed contact  64  on the other end. The curved U-shaped member is disposed around the main contact support  254  so that the upper part of the U-shaped member is captured between outer surface  260  and concave surface  268  while the lower or other part of the U-shaped portion is disposed under the housing exemplified by the lower slot motor assembly  246 . The thusly captured support arm  68  bears downwardly against the upper surface  274  of the arc runner  88  and holds it in place against the upper part  282  of the housing  246  with the tabular members  280  preventing sideways motion of the arc runner  88 . The arcing contact  88  cannot move longitudinally because it has an end  274 A thereof which is offset at right angles to the main portion thereof and is trapped in a grooved formed by one side of the housing  246  and the inner side of the main contact support  254 . 
     Referring now to FIGS. 3,  5 ,  15 ,  16 A,  16 B and  16 C, the upper slot motor assembly housing  291  is depicted. It comprises a rear plate  296 , a front plate  292  and an inner-support or mandrel  302 . The shape of the inner-support  302  is basically that of a U. Disposed on the U shaped inner-support  302  around the bite piece thereof and extending from one foot  298  to the other thereof are corresponding U-shaped layered magnetic plates  74  which correspond generally in a one-to-one relationship to the plates  78  shown in the opening  250  in the housing  246  of FIG.  15 . These plates are aligned in a layered manner from the front plate  292  to the rear plate  296 . When thusly assembled, assembly housing  291  is disposed on top of the lower slot motor assembly  246 , so that feet  298  are disposed on either side of the arc runner  88  as shown in FIG.  15 . The central opening formed thereby provides a slotted channel in which the movable arm  58  may reside and traverse during a contact opening or closing operation. Electrical current continues to flow in the movable contact arm  58  and through an electric arc between contacts  62  and  64  during a contact opening operation. This current induces a magnetic field into the closed magnetic loop provided by the combined upper and lower plates  74  and  78  respectively in the upper contact assembly  291  and lower contact assembly  246  respectively. This magnetic field interacts with the aforementioned current electromagnetically in such a way as to accelerate the movement of the opening contact arm  58  in such a manner as to more rapidly separate contacts  62  and  64 . The higher the electrical current flowing in the arc the higher the magnetic interaction and the more quickly the contacts  62  and  64  separate. For very high current this provides the aforementioned blow open operation associated with FIG.  13 . This operation is also described in the aforementioned U.S. Pat. No. 3,815,059 to Spoelman. Also the material of the housing  291  may comprise a gas evolving material such as cellulose filled Melamine Formaldehyde which helps to move the arc toward the arc chute and it flattens it against the arc plates in the form of a band or ribbon. This shape makes it easier to split the arc and move it into the arc chute, thereby obtaining the high level of arc voltage required. 
     Referring now to FIGS. 3,  15  and  17 , an attachment arrangement for the line conductor  71  and fixed contact support member  68  is depicted. In particular, a cut away portion of the base member  14  is shown in FIG.  17 . The stationary arm  68  with its characteristic U-shape is terminated in an offset load terminal  71 . There is provided in the base  14 , a line conductor fastening post  308 . A hole or opening  104  in the contact arm  68  fits over and around the post  308 . A line conductor retaining ring  310  is disposed on the fastening post  308  after the contact arm  68  has been placed thereon. Thusly configured and attached the fixed contact arm  68  is securely fixed in and to the base  14  by way of the line conductor fastening post  308  and retaining ring  310 . The region  311  in the bite portion of the U-shaped member  68  is designated as the lower slot motor assembly region and it is in this region that the previously described lower slot motor assembly  246  is disposed as can be best seen by reference to FIGS. 3 and 15. 
     Referring now to FIGS. 5 and 18, the disposition of an auxiliary switch  320  and a bell alarm  324  is shown. In particular there is an enclosure  326  shown partially broken away inside of which the auxiliary switch  320  is shown. Alternatively, a pair of auxiliary switches  320  or a pair of bell alarms  324  may be disposed within the enclosure  326  or the disposition of the auxiliary switch  320  and bell alarm  324  may be reversed. The bell alarm  324  is disposed in the same housing  326  on the other side of an insulating auxiliary wall  325 . Switch  320  has protruding from the bottom thereof an axially movable cam follower  328  which follows the upper cam surface  100 A of the cross bar assembly  100 . As described previously, when the contacts  62  and  64  are closed, the assembly  100  is in one disposition and when the contacts  62  and  64  are open, the assembly is in a second disposition. The difference between the dispositions is tracked by the cam follower  328 . The cam follower  328  interconnects with contacts (not shown) in the auxiliary switch  320  such that normally open contact  320 A is in one disposition when the contacts  62  and  64  are open and in the opposite disposition when the contacts  62  and  64  are closed. The complimentary set of contacts  320 B are in the opposite dispositions at these times. Electrical wiring  320 C as shown in FIG. 5 may be interconnected with the terminals  321  and provided to a remote location. Appropriate power for causing certain desirable functions as a result of the status and/or change of status of the auxiliary switch  320  may be provided to a subset of these wires. There is also provided a cradle follower  332  which protrudes at a right angle relative to the cam follower  328  from the other side of the enclosure  326  for interacting with or actuating the bell alarm  324 . Depending upon the status of the handle mechanism  126 , the cradle follower  322  may cause the bell alarm  324  to be in a first electrical disposition or a second electrical disposition. This arrangement may be used to alert operating personnel that the contacts are either opened or closed. Both the auxiliary switch  320  and alarm  324  are contained within one enclosure  326  which is independently removable from the circuit breaker mechanism without complete disassembly thereof by removal of the aforementioned secondary or auxiliary cover  22  (not shown) and subsequent removal of the enclosure  326 . Insertion of the enclosure  326  may occur in a similar but reverse way. 
     Referring now to FIGS. 18A and 18B, the detailed construction features of the enclosure  326  is depicted. In particular in FIG. 18A there is depicted that portion of the switch arrangement  326  shown in its entirety in FIG.  18 . In particular portion  326 A comprises an opening  332 A through which the bar  332  of FIG. 18 protrudes outwardly beyond the case  326 . Also one-half of the guiding arrangement  328 A for the plunger  328  of FIG. 18 is also shown. Two horizontal poles  450  and  452  are provided for matching up with complementary openings in the bell alarm or auxiliary switch of FIG. 18 for disposition of the bell alarm or auxiliary switch within the case  326 . There are also provided in this embodiment three openings  474 ,  476  and  478 . Also shown is sidewall  464  and sidewall  460 . Referring to FIG. 18, the complimentary portion  326 B for portion  326 A is depicted. Slightly shorter poles  454  and  456  are provided for axially aligning with poles  452  and  450  respectively as the cover  326 B is joined to cover  326 A to form the completed switch enclosure  326 . The other half of the plunger mechanism guide  328 B is also shown protruding downwardly from casing  326 B. There are also provided flexible snap devices  468 ,  470  and  472  for snappingly engaging portions of the openings  474 ,  468  and  478  respectively. Once this occurs, the two sides  328 A and  328 B joined. The sides  460  and  462  fit flush against each other and the sides  464  and  466  form an opening for access to the completed drop-in module  326  from above. The construction features for this device are similar to those used with respect to the shunt trip device  92  shown in FIG.  4  and the under voltage relay  93  shown in FIGS. 19A, B and C. The drop-in module  326  depicted in FIGS. 18,  18 A and  18 B drops into recess  18 Y in the primary cover  18  of FIG. 2 to subsequently be covered by the auxiliary or secondary cover  22 . 
     Referring now to FIGS. 5,  14 ,  18 ,  19 A,  19 B and  19 C the under voltage relay and shunt trip module  92 X is depicted for the circuit breaker  10 . Primary cover  14  has an opening therein through which the under voltage relay in  92 X is accessible. Handle  42  operates to reset the under voltage relay  92 X in the manner which will be described hereinafter with respect to FIG.  19 B. As is best shown in FIG. 18, the trip bar assembly  100  has an extension which constitutes a trip bar assembly under voltage relay interface  212 . If interface  212  is contacted in such a manner as to rotate the trip bar in the counter-clockwise direction as shown in FIG. 14, the trip bar will cause the circuit breaker  10  to trip in a manner similar to that described with respect to FIG.  14  and the solenoid trip operation associated therewith. Thus it can be seen that the circuit breaker mechanism can be tripped by either the action of the solenoid  216 , the under voltage relay  92 X, or the shunt trip mechanism  92  of FIG. 4 causing the trip bar to rotate in the counter-clockwise direction as viewed in FIG. 18 (clockwise in FIG.  14 ). 
     Referring to FIG. 19B and 19C a top view and an orthogonal view respectively of the aforementioned under voltage relay  92 X is depicted. In particular, under voltage relay  92 X has an enclosure case  92 XA in which the under voltage relay  92 X and its mechanism are disposed. There is provided an under voltage relay coil  338  which may be energized by electrical conductors connected to the under voltage relay terminals  92 B as shown best in FIG.  5 . There is provided an under voltage relay plunger arrangement  340  which is generally U-shaped having a lower section and an upper section. Plunger arrangement mechanism  340  has an opening  342  therein in which the right arm  352 A of the under voltage relay translating lever  352  is disposed. The under voltage relay translating lever  352  pivots above a fixed pivot  356 . The left arm  352 B thereof is disposed in an opening  360 A in the main plunger  360  of the under voltage relay  92 X. There is provided a fixed spring base or seat  369 . There is also provided a screw section or threads  344 A upon which an adjustment nut arrangement  344  may be disposed. Alternatively, arrangement  344  may be replaced by a thumb screw. Interposed between the fixed spring seat  369  and the adjustable nut  344  is a spring  348  which surrounds the plunger  360 . By adjusting the nut  344  on the threads  344 A the force necessary to cause an under voltage trip may be varied. The closer the nut  344  is moved to the fixed spring base or seat member  369  the more compression is displayed by the spring  348  and the harder it is for the under voltage relay to trip. On the other hand if the nut  344  is threaded further away from the fixed spring base or seat  369  the spring  348  is relaxed. In operation the spring  348  forces the plunger  360  against left arm  352 B. The under voltage relay coil is normally on and normally holds the plunger  352  in a downward direction thus exerting force against the spring  348 . In an under voltage situation, the coil  340  is de-energized as the coil voltage drops below a predetermined value, i.e. when an under voltage situation exists. Thus the spring  348  acts against the plunger  360  causing it to move outwardly to strike the trip bar assembly under voltage relay interface  212  thus causing a trip operation as described previously. 
     Referring now to FIG. 20, an orthogonal view of circuit breaker  10  is shown. In this embodiment of the invention, combination interface barriers and wiring troughs  374  are shown in place at the ends of the circuit breaker  10 . Barriers  374  are composed of insulating material and have hollow openings  375  through the longitudinal axes thereof into which electrical wiring such as auxiliary wiring  380  may be routed. Auxiliary wiring  380  may be provided to the external part of the circuit breaker  10  by way of opening  378  in the circuit breaker  10 . A similar opening  384  may be provided in the side of the circuit breaker  10 . In the prior art, auxiliary wiring is routed to the external part of the circuit breaker  10  from the opening  384 . The presence of the combination interface barrier and wiring trough  374  provides a solid insulating barrier between the incoming power leads which are interconnected with the load terminals  50 , for example. 
     Referring to FIGS. 21A and 21B, a DIN rail attachment  390  is shown. In both figures the circuit breaker  10  is shown in orthogonal view with the base  14  prominently displayed. In the case of FIG. 21A, the handle  42  is also shown for purposes of orientation. In FIG. 21A the back plane  400  of the base  14  is depicted. In this state the circuit breaker  10  may be directly interconnected to a wall of a load center or panel board. In FIG. 21B the DIN rail attachment  390  is shown attached to the back plane  400 . There is provided a single piece DIN rail attachment  390  having a singular, movable latch  394  and an inter-connected spring loaded plunger  398 . Device  390  may be securely fastened to the back plane  400  of the circuit breaker  10  by way of attachment devices  399  such as bolts. DIN rail mounting members  395  and  396  are provided for interaction with a typical DIN rail mounting arrangement. The plunger  398  may be activated to cause the movable latch  394  to clear the DIN rail during the mounting operation. The plunger  398  which is spring loaded springs back after the mounting procedure has begun causing the latch  394  to securely hold the circuit breaker  10  against the DIN rail (not shown) with the aid of members  395  and  396 . 
     Referring now to FIG. 22A a self-retaining collar for a load or line conductor is depicted. In this embodiment of the invention, the collar is disposed, as shown in FIG. 22B, on the line conductor  71 . The collar  400  comprises a formed strip of rectangular cross-section, electrically conductive material such as copper folded over four times at  406 ,  408 ,  410  and  412  to form a hollow rectangular collar. One end,  414  of the rectangular member includes a portion of peninsular material  418  bent over at  416  which is fitted or dove-tailed into a fit with an opening  420  of similar shape in the side of the wall defined by the corners  406  to  408 . In a like manner a rectangular protrusion  422  depends outwardly from the horizontal section of the bent over material emanating from fold over  406  towards the right. This latter rectangular portion is interlocked with a key member or opening  424  in the fold region  412 . This secure arrangement allows for a relatively strong collar member formed from a single unitary piece. There is provided at the top a threaded opening  426  into which a threaded member may be axially disposed for downward movement into the central enclosure  428  of the collar member  400  for compressing wires or conductor which may be inserted therein. The embodiment of the invention as shown in FIG. 22A includes two side mounted protrusions or trapping members  430 A and  430 B which transversely protrude into the central opening  428 . There is also included a sprung raised portion  436  peninsularly arranged in the middle of cutout  438 . The raised portion  436  is adapted for fitting into a hole as will be described later on in the line conductor  71  of the circuit interrupter. 
     Referring now to FIG. 22B, the collar  400  is shown in a self-retained disposition on the line conductor  71 . The line conductor  71  fits between the lower portion  440  of the dowel-like protrusions  430 A and  430 B to trap the rectangular cross-section of the line conductor  71  therebetween and between the bottom  446  of the collar  400 . The protrusion  436  protrudes upwardly into the hole  71 A in the line terminal  71  thus longitudinally fixing the relationship between the collar  440  and the conductor  71 . The entrapping protrusions  430 A and  430 B prevent the vertical movement of the collar  440  relative to the conductor  71  as viewed in FIG.  22 B. Lateral movement is prevented by the location of the sidewalls shown, for example, at  450  and  452  in FIG.  22 B.