Abstract:
A three-phase vacuum interrupter switch assembly for power distribution systems comprises an outer case having at least one window, a plurality of internal disconnect switch assemblies, and a plurality of vacuum interrupter bottle switch assemblies within the case. Each vacuum interrupter bottle switch is coupled in electrical series with a corresponding internal disconnect switch assembly. Because the open/closed state of a bottle switch is not directly observable owing to its sealed interior, a direct visible indication of the state of the three-phase vacuum interrupter switch assembly is provided by a visually detectable contact rod for each internal disconnect switch that is visible through the case window. To prevent potentially serious damage caused by arcing between the contacts of the internal disconnect switch, the internal disconnect switch is prevented from opening or closing when the bottle switches are closed. The case interior is preferably free of oil and/or SF 6  gas.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention pertains to current interrupting switches for power distribution systems. More particularly, the present invention relates to vacuum interrupter switches for underground locations of three-phase four-wire power distribution systems. 
       BACKGROUND 
       [0002]    Electric utility power distribution systems are frequently constructed underground for a variety of reasons ranging from objections to the above-ground aesthetics, the premium of above-ground space in dense urban locations, and safety concerns. Accordingly, power distribution systems heretofore constructed of poles, wires, and pole-mounted switches and transformers are being superseded and even replaced by underground systems in underground installations. 
         [0003]    Whether used in overhead or underground locations within a power distribution system, the main function of current-interrupting switches is to isolate desired sections to allow for maintenance. While overhead space is relatively open and unrestricted, space in underground installations is at a premium. Underground installations (which are also referred to as “vaults”) are relatively small and need to have enough space for all the necessary material, as well as enough room for lineman to safely work inside. 
         [0004]    For many vaults, switch installation requires using an equipment access hole which may require lifting a heavy cover and can be costly. A switch that can fit through a maintenance hole (sometimes referred to as an “access hole” or a “manhole”), however, can be very cost effective. Many switches currently used in underground vaults contain oil or SF 6  gas as an electrical insulation medium in order to make the switch small. It is possible that a switch containing oil or SF 6  gas can be made small enough to fit through a maintenance hole; however, rising environmental and safety concerns discourage the use of oil and SF 6  gas, which can each be flammable and/or explosive while presenting environmental hazards when leakage occurs or when emissions are created. Thus, utility companies are trying to move away from switches with oil or SF 6  gas. 
         [0005]    Three-phase vacuum switches have been manufactured under the Elastimold trademark by Thomas &amp; Betts Corporation (Memphis, Tenn.) that fit through a maintenance hole, and utilize vacuum interrupter bottle switches as the current-interrupting switch. The vacuum interrupter bottle switches utilized in the Elastimold switches are molded inside a rubber housing and surrounded with a thin metal sheet. Vacuum interrupter bottle switches are manufactured so that the inside components cannot be seen. The only indication as to whether or not the switch is opened or closed is the position of an exterior handle which is not the most direct type of visible evidence one wishes to have when dealing with such high voltages and currents. It is not possible to determine whether the switch is truly open or closed because the movable contacts are hidden inside. 
         [0006]    Three-phase vacuum switches have been developed to fit through a maintenance hole, and utilize vacuum interrupter switches as the current-interrupting switch. However, they do not incorporate a visible disconnect switch as a safety feature. It is not possible to determine whether a vacuum interrupter bottle switch is open or closed because the movable contacts associated with the switches are contained within the sealed body of the bottle. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention pertains to vacuum interrupter switches designed to replace oil and SF 6  gas switch assemblies, while being compact enough to fit through a 30-inch diameter maintenance hole for use in underground three-phase four-wire power distribution systems. 
         [0008]    A vacuum interrupter switch assembly constructed in accordance with the invention (hereinafter sometimes referred to simply as the “switch assembly”) includes a direct visible indication of the vacuum interrupter switch assembly&#39;s open-circuited state, a configuration that minimizes the chances of death or injury to personnel and of a spark-induced fire or explosion owing to an attempted connection of the switch assembly to the electrical grid while in an incorrect switching state, and also provides a configuration that can close into and open under a bolted fault current without the container exploding. The term “bolted fault current” is recognized by those skilled in the art to denote the large short circuit current that can flow through the vacuum interrupter switch assembly when conductors at different potentials become connected, the magnitude of which can cause arcing between opening switch contacts. 
         [0009]    Other objects, advantages and significant features of the invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, disclose a preferred embodiment of the invention. 
         [0010]    It will be understood that orientations described in this specification, such as “up”, “down”, “top”, “side” and the like, are relative, and are used for the purpose of describing an embodiment of the invention with respect to the drawings. Those of ordinary skill in the art will recognize that the orientation of the disclosed device can be varied in practice, and that the orientation used herein has been chosen for explanatory purposes only. Similarly, it will be recognized by those skilled in the art that the materials referred to herein, and particularly those identified by trademark, are examples of materials that meet the requirements and specifications mandated by safety concerns and by the use of the preferred switch assembly with electric power lines. Accordingly, other acceptable materials are within the scope of the invention whether known by generic names and/or other trademarks, or comprising other functionally equivalent material. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a left front perspective view of a preferred vacuum interrupter switch assembly constructed in accordance with the invention; 
           [0012]      FIG. 2  is a right front perspective view of the vacuum interrupter switch assembly of  FIG. 1 ; 
           [0013]      FIG. 3  is a right back perspective view of the vacuum interrupter switch assembly of  FIG. 1 ; 
           [0014]      FIG. 4  is a cut-away left side elevation view in schematic of the vacuum interrupter switch assembly of  FIG. 1 , illustrating the preferred internal layout of the disconnect switch assembly components; 
           [0015]      FIG. 5  is a cut-away right side elevation view of the vacuum interrupter switch assembly of  FIG. 1 , illustrating the internal layout of the vacuum interrupter bottle switch assembly components; 
           [0016]      FIG. 6  is a cut-away front elevation view of the vacuum interrupter switch assembly of  FIG. 1 , illustrating the preferred internal layout of components for the disconnect switch and vacuum interrupter bottle switch assemblies; 
           [0017]      FIG. 7  is a side elevation view, in schematic, of a preferred vacuum interrupter bottle switch assembly constructed in accordance with the invention, with its operating mechanism shown in cut-away schematic form; 
           [0018]      FIG. 8  is a front partially-sectioned elevation view in schematic of a preferred disconnect switch assembly constructed in accordance with the invention; 
           [0019]      FIG. 9  is an exploded right side perspective view of the vacuum interrupter switch assembly of  FIG. 1 , illustrating the preferred interlocking control assembly; 
           [0020]      FIG. 10  is an exploded view of the components fastened to the inside of the cover of the vacuum interrupter switch assembly; 
           [0021]      FIG. 11  is a left side elevation view of the preferred components fastened to the bottom of the preferred vacuum interrupter switch assembly; 
           [0022]      FIG. 12  is an explosion view of a preferred vacuum interrupter bottle switch assembly without an operating mechanism; 
           [0023]      FIG. 13  is an explosion view of the preferred three-phase vacuum interrupter bottle switch assembly without the operating mechanisms; 
           [0024]      FIG. 14  is an explosion view illustrating the components of a preferred bus connector; 
           [0025]      FIG. 15  illustrates a right front perspective view of the three-phase vacuum interrupter bottle switch assembly of  FIG. 5 ; 
           [0026]      FIG. 16  is a left elevation view of the disconnect switch assembly operating mechanism in  FIG. 4 ; 
           [0027]      FIG. 17  is a front view of the preferred disconnect switch assembly operating mechanism shown in cut-away schematic form and constructed in accordance with the invention; 
           [0028]      FIGS. 18A-T  are illustrations of components of the disconnect switch assembly operating mechanism of  FIG. 16 ; 
           [0029]      FIG. 19  is a front view of the drive shaft for the disconnect switch assembly; 
           [0030]      FIG. 20  is a side view of  FIG. 19 ; 
           [0031]      FIG. 21  is a right front perspective of the vacuum interrupter switch assembly with the front and right side panels removed; 
           [0032]      FIG. 22  illustrates an explosion view of the preferred disconnect switch insulating shield with bottom contact and connection bus; 
           [0033]      FIG. 23  is a cut-away top view of the preferred vacuum interrupter switch assembly illustrating the preferred internal layout of the disconnect switch assembly components; 
           [0034]      FIG. 24  is a lower right side perspective view of the preferred vacuum interrupter switch assembly illustrating the preferred internal layout of components; 
           [0035]      FIG. 25  is an expanded view of the preferred interlocking control assembly; 
           [0036]      FIG. 26  is a cut-away view of the preferred interlocking control assembly illustrating the preferred internal layout of some components. 
           [0037]      FIG. 27  is a side view of the preferred operating mechanism assembly for the preferred vacuum interrupter bottle switch assembly; 
           [0038]      FIG. 28  is a front view of the operating mechanism assembly of  FIG. 27 ; 
           [0039]      FIG. 29  is an internal view of the operating mechanism assembly of  FIG. 27 ; 
           [0040]      FIG. 30  is a side view of a preferred spring support rod; 
           [0041]      FIG. 31  is a top view illustration of the spring support rod of  FIG. 30   
           [0042]      FIG. 32  is a side view illustration of the preferred push-pull assembly of  FIG. 27 ; 
           [0043]      FIG. 33  is a front view illustration of the push-pull assembly of  FIG. 32 ; 
           [0044]      FIG. 34  is a side view of preferred operating shaft for the vacuum interrupter bottle assembly; 
           [0045]      FIG. 35  is a front view illustration of the preferred drive shaft assembly of  FIG. 27 ; 
           [0046]      FIG. 36  is a front view illustration of the preferred damper assembly of  FIG. 27 : 
           [0047]      FIGS. 37A-Q  are illustrations of components of the vacuum interrupter bottle switch assembly operating mechanism of  FIG. 27 ; 
           [0048]      FIGS. 38A-H  are illustrations of components of the vacuum interrupter bottle switch assembly operating mechanism of  FIG. 27 ; 
           [0049]      FIGS. 39A-N  are illustrations of components of the vacuum interrupter bottle switch assembly operating mechanism of  FIG. 27 ; 
           [0050]      FIG. 40A-D  are illustrations of components of the vacuum interrupter bottle switch assembly operating mechanism of  FIG. 27 ; 
           [0051]      FIG. 41  is a right side cut-away view of  FIG. 35 . 
           [0052]      FIG. 42  is a front elevation view of a preferred mounting frame; 
           [0053]      FIG. 43  is a side elevation view of  FIG. 42 ; 
           [0054]      FIG. 44  is a top plan view of a preferred operating handle; 
           [0055]      FIG. 45  is a front elevation view of the handle of  FIG. 44 ; 
           [0056]      FIG. 46  is a side elevation view of the handle of  FIG. 44 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0057]    Referring to  FIGS. 1-3 , a preferred three-phase, two-way, submersible loadbreak vacuum interrupter switch assembly  5  constructed in accordance with the invention is illustrated. The assembly comprises of an outer case  10 , formed from a sturdy, corrosive-resistant material. The preferred material is stainless steel. The dimensions of case  10  are preferably approximately 16.7 inches wide by 39 inches high by 25 inches deep to fit within existing access holes and underground spaces available for switching assemblies. Each switch assembly case  10  is filled with dry air. Neither oil nor SF 6  gas is used. Case  10  preferably has sides  11   a - d , bottom  13 , and cover  12  welded together along the abutting edges. Front side  11   b  has viewing window  55  and the back side  11   d  has viewing window  55 . As will become clear later, the viewing window permits personnel to view power interruption switches inside the sealed case in order to determine if the switches are open or closed, with the interior of the case  10  being illuminated through the rear window by exterior daylight, a room light, a flashlight, or other source of illumination. It is foreseeable that the vacuum interrupter switch assembly  5  will be placed against a wall, however, rendering the backside window useless, and it may accordingly be desirable to have a second window installed on the front side  11   b  to enable a flashlight to be shined into the case via the second window while the first front window is used to view the illuminated power interruption switch. Viewing window  55  on the back side can accordingly be moved to the front side, if necessary, or a third window or larger window can simply be used on the front of the illustrated case. 
         [0058]    Two sets of three power bushings ( 302   a,    302   b,    302   c  and  102   a,    102   b,    102   c ) extend out from cover  12 . As illustrated in  FIGS. 1-3 , power bushings  302   a,    302   b,  and  302   c  extend from the left region of the cover, while power bushings  102   a,    102   b,  and  102   c  extend from the right region of the cover. In use, the incoming three-phase power feeder cable is electrically coupled to power bushings  302   a,    302   b,  and  302   c.  The power bushings  102   a,    102   b,  and  102   c  are electrically coupled to branch circuits to provide three-phase power. For this invention, the preferred power bushings are manufactured under the Elastimold trademark by Thomas &amp; Betts Corporation (Memphis, Tenn.). 
         [0059]      FIG. 4  is a cut-away left side elevation view of the switch assembly  5  illustrating the preferred layout of the assembly&#39;s preferred internal disconnect switch assemblies  300   a,    300   b , and  300   c.    FIG. 5  is a cut-away right side elevation view of the preferred vacuum interrupter switch assembly  5  illustrating the preferred internal layout of the vacuum interrupter bottle switch assembly components  100   a,    100   b,  and  100   c.    FIG. 6  is a cut-away front elevation view of the preferred vacuum interrupter switch assembly illustrating the preferred internal layout of the preferred components for the disconnect switch assemblies  300   a,    300   b,  and  300   c  and vacuum interrupter bottle switch assemblies  100   a,    100   b,  and  100   c.    
         [0060]      FIG. 7  is a side elevation view, in schematic, of a preferred vacuum interrupter bottle switch assembly constructed in accordance with the invention, with its operating mechanism shown in cut-away schematic form. As illustrated in  FIGS. 7 and 12 , vacuum interrupter bottle switch assemblies  100   a,    100   b,  and  100   c  each generally comprise a power bushing  102   a - c , an insulation shield  104   a - c , a vacuum interrupter bottle switch  108   a - c , a common bus connector  110   a - c , a push-pull insulator  116   a - c , and an operating mechanism assembly  150   a - c . For the sake of brevity, it will be understood that a description of a component having an “a” suffix following its reference numeral will also serve as a description of a corresponding component having a “b” or “c” suffix service unless otherwise stated in the specification or as evident from the Figures. Likewise, all three corresponding components may be referred to with the suffix “a-c” following the reference numeral. 
         [0061]    As illustrated in  FIGS. 5 and 6 , vacuum interrupter bottle switch assembly  100   a  extends vertically upward and out of cover  12 . Vacuum interrupter bottle switch assembly  100   b  extends vertically upward and out of cover  12 , behind vacuum interrupter bottle switch assembly  100   a  and generally parallel thereto. Vacuum interrupter bottle switch assembly  100   c  extends vertically upward and out of cover  12 , behind vacuum interrupter bottle switch assembly  100   b  and generally parallel thereto. 
         [0062]      FIG. 8  is a front partially-sectioned elevation view in schematic of a preferred disconnect switch assembly constructed in accordance with the invention. Disconnect switch assemblies  300   a,    300   b  and  300   c  are all represented in  FIG. 8 , with the nomenclature  300   a - c . Corresponding elements of the respective disconnect switch assemblies are denoted similarly. Disconnect switch assembly  300   a - c  is generally comprised of a power bushing  302   a - c , an insulating shield  304   a - c , a transparent insulating shield  318   a - c , top contact  306   a - c  and bottom contact  312   a - c , a contact rod  308   a - c , an insulating shield  314   a - c , and a push-pull insulator  316   a - c . As illustrated in  FIGS. 4 and 6 , internal disconnect switch assembly  300   a  extends vertically upward and out of cover  12 . Internal disconnect switch assembly  300   b  extends vertically upward and out of cover  12  behind internal disconnect switch assembly  300   a  and generally parallel thereto. Internal disconnect switch assembly  300   c  extends vertically upward and out of cover  12  behind internal disconnect switch assembly  300   b  and generally parallel thereto. 
         [0063]    As illustrated in  FIG. 6 , each vacuum interrupter bottle switch assembly  100   a - c  is mechanically and electrically coupled to a corresponding disconnect switch assembly  300   a - c  through bus  140   a - c . Bus  140   a - c  is connected to L-bracket  310   a - c  (best shown in  FIG. 8 ) of disconnect switch assembly  300   a - c  and to connector  110   a - c  (best shown in  FIG. 7 ) of vacuum interrupter bottle switch assembly  100   a - c.    
         [0064]    As illustrated in  FIG. 4 , disconnect switch assemblies  300   a,    300   b,  and  300   c  (shown in the open position) are connected to drive shaft  363  which is mechanically coupled to operating mechanism  350 . Coupling to drive shaft  363  allows the disconnect switch assemblies  300   a - c  to be controlled in unison. Turning drive shaft  363  clockwise will push contact rods  308   a - c  through guides  305   a - c  from the shown “open” position into top contacts  306   a - c , the “closed” position where upper contacts  306   a - c  and bottom contacts  312   a - c  are electrically coupled through contact rods  308   a - c . From the closed position, turning drive shaft  363  counter clockwise pulls contact rods  308   a - c  out from top contacts  306   a - c  and back down to bottom contacts  312   a - c  and into the open position. 
         [0065]    As illustrated in  FIG. 15 , vacuum interrupter bottle switch assemblies  100   a,    100   b,  and  100   c  are mechanically coupled to drive shaft  60  through operating mechanisms  150   a,    150   b,  and  150   c,  respectively. Coupling to drive shaft  60  allows the vacuum interrupter bottle switch assemblies  100   a - c  to be controlled in unison. Referring to  FIG. 6 , the vacuum interrupter bottle switch assemblies  100   a - c  are seen in the open position. Turning drive shaft  60  clockwise results in pushing up the moveable contact of vacuum interrupter bottle switch  108   a - c  such that the internal contacts are pushed together. This is the closed position for the vacuum interrupter bottle switch assembly. From the closed position, turning drive shaft  60  counterclockwise pulls the moveable contact of vacuum interrupter bottle switch  108   a - c  downwards so that the internal contacts are pulled apart and into the open position. 
         [0066]      FIG. 9  is an exploded right side perspective view of the vacuum interrupter switch assembly of  FIG. 1 , illustrating the preferred interlocking control assembly. As illustrated in  FIG. 9 , interlocking control assembly  40  is preferably affixed to front side  11   b.  Drive shafts  60  and  363  are mechanically connected to interlocking control assembly  40  via control shafts  41   a  and  41   b,  respectively. Interlocking control assembly  40  ensures proper and safe operation of the switch by preventing the internal disconnect switch assemblies  100   a - c  from opening or closing unless the vacuum interrupter bottle switches  108   a - c  are open. 
         [0067]    If an underground vault has a 30-inch diameter access hole, then switch assembly  5  described above can fit through the hole, bottom side first, and into the vault. If smaller dimensions are desired, then a variety of dielectric materials can be utilized. Oil or SF 6  could also be used, but would re-introduce environmental hazards to the disclosed assembly and negate some of its features and benefits. 
         [0068]    A variety of grounding methods are available for the switch assembly  5 . One can, for example, weld ground rods to the case  10  so that a grounding wire can be connected to the rods. Alternatively, a bracket can be used so that a grounding wire with a terminal can be bolted on. Once positioned inside the vault, the vacuum interrupter switch can be grounded and synthetic power cables attached to power bushings  102   a - c  and  302   a - c  through power cable elbows such as those manufactured under the Elastimold trademark by Thomas &amp; Betts Corporation (Memphis, Tenn.) and under the Cooper trademark by Cooper Power Systems (Waukesha, Wis.). For this invention, Elastimold is the preferred brand. 
       Assembly 
       [0069]    The assembly of the preferred vacuum interrupter switch assembly will now be discussed. The construction and operation of a vacuum interrupter bottle switches are known to those of ordinary skill in the art, and are not discussed here for the sake of brevity. 
         [0070]      FIG. 10  is an exploded view of the components fastened to the inside of the cover of the vacuum interrupter switch assembly, and  FIG. 11  is a left side elevation view of the preferred components fastened to the bottom of the preferred vacuum interrupter switch assembly. Referring to  FIGS. 10 and 11 , support bars  14   a - d ,  15   a - c , and  16  are bolted into place onto cover  12  and bottom  13  through threaded holes. Floor mounting brackets  21  are fastened with bolts, nuts, and lock washers to the underside of bottom  13  at points  98 . Cylindrical support rods  404  and  406  are bolted to bottom  13  through threaded holes. As best illustrated in  FIGS. 5 and 11 , rectangular support rod  408  is laid on support rods  404 . Support stand  410  is laid on rectangular support rod  408  and support rods  406 . Support stand  410  is bolted to support rods  406  and, through rectangular support rod  408 , to support rods  404 . 
         [0071]    Power bushing  102   a,    102   b,  and  102   c  are inserted in respective holes in the cover and welded to cover  12 . Power bushing  302   a,    302   b,  and  302   c  are inserted in respective holes in the cover and welded to cover  12 . Nut  128   a  and a lock washer are installed on the threaded portion of stud adapter  130   a  which is then threaded into power bushing  102   a.  Similarly, nuts and lock washers are installed on the threaded portion of stud adapters threaded into power bushing  102   b  and  102   c.    
         [0072]    A lock washer and connector  320   c  are threaded onto the stud of power bushing  302   c . The large end of top contact  306   c  clasps onto the small end of connector  320   c.  Spring  321   c  is placed onto top contact  306   c  to hold it firmly onto connector  320   c.  Spacer  322   c  is placed into a small groove inside the small end of top contact  306   c.  Spring  323   c  is placed around the small end of top contact  306   c.  The same is done for the other two power bushings. 
         [0073]    As best shown in  FIG. 10 , the right ends of shields  104   a - c  have holes  105 . The ends of shields  104   a - c  without the holes  105  are installed onto power bushing  102   a,    102   b,  and  102   c , respectively. Similarly, the ends of shields  304   a - c  without holes  303  are installed onto power bushing  302   a,    302   b,  and  302   c,  respectively. 
         [0074]    Guides  305   a - c  are each cylindrically-shaped with an interior that is slanted so that one end has a smaller interior cross-section than the other end. Guides  305   a,    305   b,  and  305   c  are inserted smaller end first into power bushings  302   a,    302   b,  and  302   c,  respectively. All holes  307  are aligned with holes  303  and inserted with a peg  309 . 
       Vacuum Interrupter Bottle Switch Assembly  100   
       [0075]    Assembly of the preferred vacuum interrupter bottle switch assembly is best understood with reference to  FIGS. 12 and 13 . A lock washer  106  is installed onto the stationary contact for vacuum interrupter bottle switches  108   a,    108   b,  and  108   c  which are then threaded into stud adapters  130   a,    130   b,  and  130   c,  respectively. 
         [0076]    Four insulating cylinders  119  cover the four short studs surrounding the moveable contact of vacuum interrupter bottle switch  108   a.  A short threaded cylindrical spacer  121  and a long threaded cylindrical spacer  120  are screwed onto the moveable contact for vacuum interrupter bottle switch  108   a  and tightened against one another. The same is done to vacuum interrupter bottle switches  108   b  and  108   c.    
         [0077]    A threaded rod  127   a  with metal spacer  126   a  has lock washers  131  placed on both ends and is screwed into the internal threads of the movable contact for vacuum interrupter bottle switch  108   a.  The same is done to vacuum interrupter bottle switches  108   b  and  108   c.    
         [0078]    Insulation cover tops  132   a,    132   b,  and  132   c  are loosely installed over vacuum interrupter bottle switches  108   a,    108   b,  and  108   c,  respectively. Assembly holder  129  is loosely installed over vacuum interrupter bottle switches  108   a,    108   b,  and  108   c  through respective holes  129   a ,  129   b,  and  129   c.  An O-ring  122  is fitted around the movable contact end of vacuum interrupter bottle switches  108   a,    108   b,  and  108   c.  From openings  135   a,    135   b,  and  135   c,  insulating covers  134   a,    134   b,  and  134   c  are fitted over vacuum interrupter bottle switches  132   a,    132   b,  and  132   c , respectively. 
         [0079]    Bus connector  110   a - c , as illustrated in  FIGS. 13 and 14 , comprises a generally cylindrical body with a rectangular flange at one end that has holes  107 . The other end of the connector  110   a - c  has four holes  109  on the other end with internal grooves  111 . Within groove  111  is a disposed band of torsion or leaf spring contact material  112 . Contact elements of this type are sold, for example, under the Multilam trademark. C-clips  113  secure the Multilam contact  112  within groove  111 . 
         [0080]    As best illustrated in  FIG. 13 , bus connector  110   a  is inserted into insulating cover  134   a  through the slotted opening end, around metal spacer  126   a,  and installed onto vacuum interrupter bottle switch  108   a  by aligning its four holes  109  with the four studs (not shown) surrounding the movable contact of vacuum interrupter bottle switch  108   a.  An insulating spacer  118  is inserted into bus connector  110   a,  and around metal spacer  126   a,  with its holes  117  aligned with holes  109 . Four screws  125  are inserted through holes  117  and  109  and screwed into the four studs surrounding the movable contact for vacuum interrupter bottle switch  108   a.  The same is done with corresponding components to respect to vacuum interrupter bottle switches  108   b  and  108   c.    
       Operating Mechanism Assembly  150   
       [0081]      FIGS. 27-28  show right side and front perspective views of a preferred operating mechanism assembly  150  ( FIGS. 7 ,  15 ) constructed in accordance with the invention.  FIG. 29  is an internal view of the operating mechanism assembly  150 . The operating mechanism assembly  150  comprises a drive shaft assembly  151 , push-pull assembly  152 , and damper assembly  153 , and framing components. Three identical operating mechanisms are preferably used, and are designated as  150   a,    150   b,  and  150   c  herein. 
         [0082]    Referring to  FIGS. 35 ,  37 A-Q, and  38 A-H, the drive shaft assembly  151  is assembled with spring shaft  167  secured between the arms of rotating clevis  165  ( FIG. 37B ) by inserting pin  166  through holes  165   a  and hole  167   a  of spring shaft  167 . Spring  169  is slid onto spring shaft  167  and held in place with screws at points  167   c.  Spring  169  is important since it controls the opening and closing speed of vacuum interrupter bottle switch  108 . Pin  166  is held in place with cotter pins inserted into holes  166   a.  Lever arm  161  is fitted onto rotating clevis  165  with an end of pin  166  inserted into curved slot  161   a  and shaft opening  161   b  aligned with shaft opening  164  of rotating clevis  165 . Pivot point  161   c  protrudes away from rotating clevis  165 . Lever arm  162  is fitted onto rotating clevis  165  with the other end of pin  166  inserted into curved slot  162   a  and shaft opening  162   b  aligned with shaft opening  164  of rotating clevis  165 . Pivot point  162   c  protrudes away from rotating clevis  165 . 
         [0083]    End  170   c  of toggle link  170   a  is fastened to pivot point  161   c  with a retaining washer. End  170   d  of toggle link  170   a  along with end  171   c  of toggle link  171   a  are fastened by retaining washers to pivot point  173   a  of clevis  172 . Toggle link  170   b  is substantially identical in structure to toggle link  170   a.  End  170   c  of toggle link  170   b  is fastened to pivot point  162   c  with a retaining washer. End  170   d  of toggle link  170   b  along with end  171   d  of toggle link  171   b  is fastened by retaining washers to pivot point  173   b  of clevis  172 . (Note: Toggle link  171   b  is substantially identical in structure to toggle link  171   a  (FIGS.  37 N,O)). A threaded spacer  183  ( FIG. 39A ) is fitted between toggle links  170   a  and  170   b  and screwed into place at point  170   e  of both toggle links. 
         [0084]    Referring to  FIGS. 27-33  and  38 A-H, the push-pull assembly  152  is assembled with bolt  176  inserted through hole  179   d  of spring support rod  179 , bottom spring holder  178 , over-travel spring  177 , and top spring holder  178 . A spring washer, two nuts, and a second spring washer are screwed onto bolt  176 . 
         [0085]    Referring to  FIGS. 27 ,  29 ,  36  and  39 , a damper assembly  153  includes a stopper  188  which is inserted through spacer  189 , through hole  186  on support  185  and held in place with a cotter pin. 
         [0086]    Drive shaft assembly  151  is connected to push-pull assembly  152  by fastening the end  171   d  of toggle link  171   a  to the end  179   a  of spring support rod  179  with a retaining washer, and fastening the end  171   d  of the toggle link  171   b  to the end  179   b  of spring support rod  179  with a retaining washer. In  FIGS. 32 and 33 , toggle links  171   a - b  of drive shaft assembly  151  are shown attached to push-pull assembly  152 . 
         [0087]    Referring to  FIGS. 39 and 40 , flanged spacers  200  are inserted into hole  202   a  on frame  202  and hole  201   a  on frame  201  from the non-flanged side. Spring support rod end  179   b  is inserted into slot  202   b  on frame  202 . Bolt  197  is inserted into hole  202   c  of frame  202  and screwed into threaded spacer  184   a  at end  184   d.  A second bolt  197  is inserted into hole  202   e  of frame  202  and screwed into threaded spacer  184   b  at end  184   d.  Pivot rod  175  is inserted into pivot shaft  174  of clevis  172  with end  175   b  inserted into hole  202   g  and fastened in place with a retaining washer. Damper assembly  153  is installed onto spacer  184   b  through hole  185   a  and positioned between the arms of clevis  172  and on pivot shaft  174  at support point  185   b.    
         [0088]    Spring support end  179   a  is inserted into slot  201   b  on frame  201 . A bolt  197  is inserted into hole  201   c  of frame  201  and screwed into threaded spacer  184   a  at end  184   c.  Another bolt  197  is inserted through hole  201   e  of frame  201  and screwed into threaded spacer  184   b  at end  184   c.  End  175   a  of pivot rod  175  is inserted through hole  201   g  and fastened into place with a retaining washer. Pin  168  is inserted through hole  202   d,  slot  167   b,  and hole  201   d  and fastened in place with retaining washers. The screws in points  167   c  are removed. 
         [0089]    A support screw is fitted with a flat washer, nut, and spring washer and then screwed into hole  179   f  at spring support rod end  179   b.  A support screw is fitted with a flat washer, nut, and spring washer and then screwed into hole  202   f  of frame  202 . Spring end  182   c  of spring  182  is hooked onto the support screw at support rod end  179   b.  Spring end  182   d  of spring  182  is hooked on the support screw at hole  202   f  of frame  202 . A support screw is fitted with a flat washer, nut, and spring washer and then screwed into hole  179   e  at spring support rod end  179   a . A second support screw is fitted with a flat washer, nut, and spring washer and then screwed into hole  201   f  of frame  201 . Spring end  182   c  of another spring  182  is hooked onto the support screw at support rod end  179   a.  Spring end  182   d  of the second spring  182  is hooked on the support screw at hole  201   f  of frame  201  to complete the assembly of an operating mechanism designated as  150   a.  Two more operating mechanisms are assembled in the same manner and designated as  150   b  and  150   c.    
         [0090]    The small end of push-pull insulator  116   a  ( FIGS. 7 ,  13 ) is screwed onto threaded rod  127   a  ( FIG. 13 ). The large end of push-pull insulator  116   a  is screwed onto bolt  176   a  ( FIGS. 32 ,  33 ) of operating mechanism  150   a.  The small end of push-pull insulator  116   b  is screwed onto threaded rod  127   b.  The large end of push-pull insulator  116   b  is screwed onto bolt  176   b  of operating mechanism  150   b.  The small end of push-pull insulator  116   c  is screwed onto threaded rod  127   c . The large end of push-pull insulator  116   c  is screwed onto bolt  176   c  of operating mechanism  150   c.    
         [0091]    Turning to  FIGS. 13 and 15 , assembly holder  129  is fitted onto insulating covers  134   a ,  134   b,  and  134   c  through respective holes  129   a,    129   b,  and  129   c.  Insulation cover tops  132   a ,  132   b,  and  132   c  are fitted onto insulating covers  134   a,    134   b,  and  134   c,  respectively, with assembly holder  129  held firmly between them. 
         [0092]    The vacuum interrupter bottle switches  108   a - c  are mechanically linked together for operation in unison by driveshaft  60 . A holding bar  217  is placed in slots  60   a,    60   b,  and  60   c  of drive shaft  60 . End  60   d  of drive shaft  60  is slid through operating mechanism  150   c  through its flanged spacer  200  of frame  202 . End  60   d  of drive shaft  60  is then slid through operating mechanism  150   b  through its flanged spacer  200  of frame  202 . End  60   d  of drive shaft  60  is then slid through operating mechanism  150   a  through its flanged spacer  200  of frame  202 . Operating mechanism  150   a  is positioned over hole  60   a.  Operating mechanism  150   b  is positioned over hole  60   b.  Operating mechanism  150   c  is positioned over hole  60   c.  Drive shaft  60  is rotated until the holding bars  217  in slots  60   a,    60   b,  and  60   c  fall into notches  216  of each operating mechanism. Drive shaft  60  is held in place with retaining washers at grooves  60   f  ( FIG. 34 ). A lever rod  199  ( FIG. 28 ) is inserted through drive shaft hole  60   g.    FIG. 15  best illustrates the assembled three-phase vacuum interrupter bottle switch assemblies  100   a,    100   b,  and  100   c . 
       Disconnect Switch Assembly  350   
       [0093]      FIG. 16  is a side view of disconnect switch assembly operating mechanism  350 .  FIG. 17  is an internal view of operating mechanism  350 .  FIGS. 18   a  through  18 T illustrate the components of the operating mechanism  350 .  FIGS. 19 and 20  are front and side views, respectively, of disconnect switch assembly drive shaft  363 . 
         [0094]    As illustrated in  FIG. 16 , pin  366  ( FIG. 18L ) is inserted through spring rod hole  370   a  ( FIG. 18N ), clevis holes  361   a  ( FIG. 18G ), and fastened to clevis  361  with retaining washers  391  at grooves  366   a  ( FIG. 18L ). End  370   b  ( FIG. 18N ) of spring rod  370  is inserted into spring tube  367  ( FIG. 18J ) through opening  367   a.  Spring  369  ( FIG. 18Q ) is fitted over spring tube  367  and pin  368  ( FIG. 18O ) is inserted through holes  367   b.  Pin  368  is inserted into hole  401   d  of frame  401  (FIGS.  18 C,D) and hole  402   d  of frame  402  (FIGS.  18 A,B) and fastened with retaining washers  391  at grooves  368   a  ( FIG. 18O ). 
         [0095]    Flanged spacers  400  ( FIG. 18H ) are fitted onto drive shaft  363  ( FIG. 19 ) and at both ends of clevis  361  with the flanged ends butting against the ends of clevis  361 . End  400   a  of flanged spacers  400  ( FIG. 18I ) is inserted into hole  401   a  of frame  401  ( FIG. 18C ) and hole  402   a  of frame  402  ( FIG. 18A ). Openings  400   c  of flanged spacers  400  ( FIG. 18H ) are aligned with opening  361   d  of clevis  361  ( FIG. 18G ). End  363   a  of drive shaft  363  ( FIG. 19 ) is fitted through retaining ring  384  ( FIG. 18J ), opening  400   c  in frame  402  ( FIG. 18A ), clevis shaft opening  361   d  of clevis  361  ( FIG. 18G ) and openings  400   c  in frame  401  ( FIG. 18C ) and fastened with retaining rings  384  ( FIG. 18J ) at grooves  363   e  ( FIG. 19 ). Holes  361   c  ( FIG. 18F ) and hole  363   c  ( FIG. 19 ) are aligned, and tapered pin  378  ( FIG. 18E ) is inserted slit end  379  first. 
         [0096]    Frames  401  and  402  are held a desired distance apart by spacer tubes  374 . The openings of spacer tubes  374  ( FIG. 18R ) are aligned with holes  401   c  of frame  401  (FIGS.  18 C,D) and holes  402   c  of frame  402  (FIGS.  18 A,B). Bolts are inserted through holes  401   c,  spacer tubes  374 , and  402   c  and fastened with lock washers and nuts. 
         [0097]    Guide rod  372  controls the degree of movement of the clevis  361 . Guide rod  372  ( FIG. 18S ) is inserted through slot  401   b  of frame  401  ( FIG. 18C ), holes  361   b  of clevis  361 , and slot  402   b  of frame  402  ( FIG. 18A ). Holes  373  of guide rod  372  ( FIG. 18S ) are positioned between the arms of clevis  361 . Straight end  381  of retaining pins  380  ( FIG. 18T ) are inserted through holes  373  until section  382  of pins  380  surrounds guide rod  372 . 
         [0098]    Referring to  FIGS. 11 ,  42 , and  43 , end  363   b  of driveshaft  363  is fitted through hole  403   a  of frame  403  and frames  401 ,  402 , and  403  are fastened to bottom  13  through mounting nuts  401   e,    402   e,  and  403   b,  respectively. 
         [0099]    As illustrated in  FIGS. 6 ,  11 ,  21 ,  40 A, and  40 C, each operating mechanism  150   a  is bolted to support stand  410  through mounting nuts  201   h  and  201   i  at points  411   a  and  202   h  and  202   i  at points  411   b.  Operating mechanism  150   b  is bolted to support stand  410  through mounting nuts  201   h  and  201   i  at points  412   a  and  202   h  and  202   i  at points  412   b.  Operating mechanism  150   c  is bolted to support stand  410  through mounting nuts  201   h  and  201   i  at points  413   a  and  202   h  and  202   i  at points  413   b.    
         [0100]    As illustrated in  FIGS. 6 and 22 , L-bracket  310   a  is bolted through hole  311   a  to insulating shield  314   a  at point  313   a.  Connector  325   a - c  are similarly shaped as connector  320   a - c , except shorter and wider in diameter. The large end of bottom contact  312   a  clasps onto the small end of connector  325   a.  Spring  326  is placed onto bottom contact  312   a  to hold it firmly onto connector  325   a.  Spacer  327  is placed into a small groove inside the small end of bottom contact  312   a.  Spring  328  is placed around the small end of bottom contact  312   a.  Bolts are inserted through support holes (not shown) in L-bracket  310   a  through holes  142   a  of connection bus  140   a,  and into holes at the bottom of connector  325   a.  Similarly, L-bracket  310   b  is bolted through hole  311   b  to insulating shield  314   b  at point  313   b.  The large end of bottom contact  312   b  clasps onto the small end of connector  325   b.  Spring  326  is placed onto bottom contact  312   b  to hold it firmly onto connector  325   b.  Spacer  327  is placed into a small groove inside the small end of bottom contact  312   b.  Spring  328  is placed around the small end of bottom contact  312   b . Bolts are inserted through support holes (not shown) in L-bracket  310   b  through holes  142   b  of connection bus  140   b,  and into holes at the bottom of connector  325   b.  Likewise, L-bracket  310   c  is bolted through hole  311   c  to insulating shield  314   c  at point  313   c.  The large end of bottom contact  312   c  clasps onto the small end of connector  325   c.  Spring  326  is placed onto bottom contact  312   c  to hold it firmly onto connector  325   c.  Spacer  327  is placed into a small groove inside the small end of bottom contact  312   c.  Spring  328  is placed around the small end of bottom contact  312   c.  Bolts are inserted vertically through support holes (not shown) in L-bracket  310   c  through holes  142   c  of connection bus  140   c,  and into holes at the bottom of connector  325   c.    
         [0101]    As illustrated in  FIGS. 4 ,  6  and  8 , a gasket  319  is placed around the small end of each push-pull insulator  316 . Contact rod  308   a  is threaded into the top side of push-pull insulator  316   a  and clevis-shaped connector  330   a  is bolted to the bottom side of push-pull insulator  316   a . A peg  329  is inserted and fastened to connector  330   a  and rod  332   a  through arm holes  331  and  333 , respectively. Similarly, contact rod  308   b  is threaded into the top side of push-pull insulator  316   b  and clevis-shaped connector  330   b  is bolted to the bottom side of push-pull insulator  316   b . A peg  329  is inserted and fastened to connector  330   b  and rod  332   b  through arm holes  331  and  333 , respectively. Contact rod  308   c  is threaded into the top side of push-pull insulator  316   c  and clevis-shaped connector  330   c  is bolted to the bottom side of push-pull insulator  316   c.  A peg  329  is inserted and fastened to connector  330   c  and rod  332   c  through arm holes  331  and  333 , respectively. Contact rod  308   a  is inserted into insulating shield  314   a  and through bottom contact  312   a.  Contact rod  308   b  is inserted into bottom contact  312   b  and insulating shield  314   b . Contact rod  308   c  is inserted into bottom contact  312   c.    
         [0102]    Referring to  FIGS. 6 ,  21 , and  23 , tank side  11   a  is bolted to support bar  15   a  and to support bar  16 . Transparent cylinder  318   a  is fitted on top of the slotted end for insulating shield  314   a.  The top end of transparent cylinder  318   a  is fitted to the bottom end of insulating shield  304   a  and insulating shield  314   a  is bolted to tank side  11   a  at bolting points  18   a.  Similarly, transparent cylinder  318   b  is fitted on top of the slotted end for insulating shield  314   b.  The top end of transparent cylinder  318   b  is fitted to the bottom end of insulating shield  304   b  and insulating shield  314   b  is bolted to tank side  11   a  behind insulating shield  314   a  and generally parallel thereto at bolting points  18   b.  Likewise, transparent cylinder  318   c  is fitted on top of the slotted end for insulating shield  314   c.  The top end of transparent cylinder  318   c  is fitted to the bottom end of insulating shield  304   c  and insulating shield  314   c  is bolted to tank side  11   a  behind insulating shield  314   b  and generally parallel thereto at bolting points  18   c.    
         [0103]    As illustrated in  FIGS. 4 ,  6 , and  19 , a peg  329  is inserted and fastened to rod  332   a  and drive shaft lever arms  364   a  through arm holes  334  and  365 , respectively. A peg  329  is inserted and fastened to rod  332   b  and drive shaft lever arms  364   b  through arm holes  334  and  365 , respectively. A peg  329  is inserted and fastened to rod  332   c  and drive shaft lever arms  364   c  through arm holes  334  and  365 , respectively. 
         [0104]    When properly assembled, and as best illustrated in  FIGS. 4 ,  6 , and  8 , turning drive shaft  363  clockwise will move contact rods  308   a - c  through bottom contacts  312   a - c , up through guide  305   a - c  and into top contacts  306   a - c . This is referred to as the closed position. Top contact  306   a  will be electrically coupled to bottom contact  312   a  through contact rod  308   a.  Top contact  306   b  will be electrically coupled to bottom contact  312   b  through contact rod  308   b.  Top contact  306   c  will be electrically coupled to bottom contact  312   c  through contact rod  308   c . Contact rods  308   a - c  can be seen through transparent insulating shields  318   a - c  and viewing windows  55 . From the closed position, turning drive shaft  363  counterclockwise will move contact rods  308   a - c  out of top contacts  306   a - c , through guides  305   a - c , and down into bottom contacts  312   a - c  as illustrated in  FIG. 8 . This is the open position. Top contacts  306   a - c  are not electrically coupled to bottom contacts  312   a - c  and contact rods  308   a - c  are not visible inside transparent insulating shields  318   a - c . As best illustrated in  FIG. 6 , connection bus  140   a  is bolted to bus connector  110   a  ( FIG. 13 ) through holes  143  and holes  107 , respectively. Connection bus  140   b  is bolted to bus connector  110   b  through holes  143  and holes  107 , respectively, behind connection bus  140   a  and generally parallel thereto. Connection bus  140   c  is bolted to bus connector  110   c  through holes  143  and holes  107 , respectively, behind connection bus  140   b  and generally parallel thereto. 
         [0105]    Referring to  FIGS. 5 ,  11 ,  21  and  24 , two long cylindrical spacer rods  414  are bolted onto bottom  13  at points  415  and extend vertically upwards to cover  12  where they are bolted at points  416 . Two each long cylindrical spacer rods  417  are bolted onto support bars  15   c  and  16  on bottom  13  and extend vertically upwards to support bars  15   a  and  15   b  on cover  12 . Two long cylindrical spacer rods  418  are bolted onto support bars  14   c  and  14   d  on bottom  13  and extend vertically upwards to support bars  14   a  and  14   b  on cover  12 . 
         [0106]    As best illustrated in  FIGS. 1 ,  9 , and  23 , a rubber cushion  52  is fitted into hole  62  of the tank&#39;s front side lib. A window  55  with an O-ring  56  fitted along the edge is placed over hole  62  of tank side  11   b.  Window holder  57  is placed over window  55  and O-ring  56  from the outside of tank side  11   b  and window backplate  58  is placed over hole  62  from the inside of tank side  11   b.  Window backplate  58  is bolted through holes  58   a  and  59  to window holder  57  at threaded holes  57   a  (not shown). The same method is used to place a window  55  onto tank side  11   d  as shown in  FIGS. 3 and 24 . 
         [0107]    It may now be appreciated that the viewing windows  55  ( FIGS. 1-3 ) allow an operator to look inside vacuum interrupter switch assembly  5  to see whether or not disconnect switch assemblies  300   a - c  are in the open or closed position. In the closed position, contact rods  308   a - c  will be seen inside transparent insulating shields  318   a - c . In the open position, contact rods  308   a - c  will not be seen inside transparent insulating shields  318   a - c.    
         [0108]    As illustrated in  FIG. 24 ,  0 -rings  23  are fitted into grooves  24  on gas vent plug  22  and inserted into gas vent  17 . Holes  26  of gas vent  17  and holes  25  of gas vent plug  22  are aligned and cotter pin  27  is inserted. 
       Interlocking Control Assembly  40   
       [0109]    Proper integration of a visible disconnect switch should preferably include proper procedures for opening and closing the vacuum interrupter switch assembly. The interlocking control assembly preferably used herein ensures that correct procedures are taken to open and close the vacuum interrupter switch assembly  5 . Interlocking control assembly  40  accordingly prevents the internal disconnect switch assemblies  100   a - c  from opening or closing unless the vacuum interrupter bottle switches  108   a - c  are open. 
         [0110]      FIG. 25  illustrates an expanded view of the preferred interlocking control assembly  40 . Threaded cover spacers  30  and spacer guides  64   a  and  64   b  are welded into place on backplate  54 . Referring to  FIGS. 9 ,  25 , and  26 , control assembly backplate  54  is bolted to front side  11   b  through holes  63  and  31 , respectively. O-rings  50  are fitted into grooves  51  of control shafts  41   a  and  41   b.  Control arm  42  has studs  44   a  and  44   b  inserted in holes  42   b.  Control arm  43  has studs  44   c  and  44   d  inserted in holes  43   b.    
         [0111]    Referring to  FIGS. 1 ,  2 ,  9 ,  23  and  25 , the slotted end of control shaft  41   a  for vacuum interrupter bottle switch assemblies  100   a - c  is inserted through control shaft well  29   a  of front side  11   b,  through hole  28   a  of backplate  54 , and into control arm  42  at opening  42   a.  Hole  45  of control shaft  41   a  is aligned with hole  42   c  of control arm  42  and bolted together. The slotted end of control shaft  41   b  for disconnect switch assemblies  300   a - c  is inserted through its control shaft well  29   b  of front side  11   b,  through hole  28   b  of backplate  54 , and into control arm  43  at opening  43   a.  Hole  47  of control shaft  41   b  is aligned with hole  43   c  of control arm  43  and bolted together. Spring  74  is placed around threaded spacer  73 . Spring  75  is placed around spacer  46 . 
         [0112]    Rod  71  is inserted through the large hole of blocker guide bar  68  and fastened near the middle with retaining washers. Blocker  66  is screwed to blocker guide bar  68  through holes  66   b  and  68   b,  respectively, with rod  71  being inserted through hole  66   a  of blocker  66 . 
         [0113]    Pivot rod  72  is inserted through hole  69   a  of blocker guide bar  69 , through slot hole  70   b  of toggle bar  70 , and through hole  67   a  of blocker  67  and fastened near the middle with retaining washers. A peg  70   d  is installed into peg hole  70   c  with peg  70   d  extending inwards. 
         [0114]    Toggle bar  70  is placed onto spacer  46  through pivot hole  70   a  and fastened with a retaining washer. Guide bar  69  is placed between spacer guides  64   b  and end  72   b  of pivot rod  72  is inserted into slot  54   b  of backplate  54 . After installation, the flat portion of control arm  43  will be between blocker  67  and guide bar  69 . The back end of rod  71  is inserted into slot  54   a  of backplate  54  and guide bar  68  is placed between spacer guides  64   a.  After installation, the flat portion of control arm  42  will be between blocker  66  and guide bar  68 . 
         [0115]    As best illustrated in  FIG. 25 , a screw and washer is screwed into holes  48   a  and  48   b  on backplate  54 . As best illustrated in  FIG. 26 , spring end  74   a  pushes against rod  71 . Spring end  74   b  pushes against the screw at hole  48   a  and held down by the washer. Spring end  75   a  pushes against the screw at hole  48   b  and held down by the washer. Spring end  75   b  pushes against peg  70   d  of toggle bar  70 . 
         [0116]    When properly assembled,  FIG. 26  illustrates the positions of the interlocking control assembly  40  components when the disconnect switch assemblies  300   a - c  are in the closed position and the vacuum interrupter bottle switch assemblies  100   a - c  in the open position. As shown, control arm  42  can only rotate clockwise and control arm  43  can only rotate counterclockwise. When control arm  42  is rotated clockwise, stud  44   b  will push toggle bar  70  so that it rotates counterclockwise around spacer  46  and pushes guide bar  69  downwards towards control arm  43  guided by spacers  64   b.  Once the rotation is completed, blocker  67  covers hole  43   a  of control arm  43  to prevent access with handle  220  ( FIG. 44-46 ). Guide bar  69  is also positioned to prevent control arm  43  from rotating counterclockwise by blocking stud  44   d  of control arm  43 . From this point, control arm  42  must be rotated counterclockwise first before control arm  43  can rotate counterclockwise. After control arm  42  is rotated counterclockwise, spring end  75   b  pushes against peg  70   d  so that toggle bar  70  rotates clockwise and guide bar  69  is pulled upwards to allow movement for control arm  43 . 
         [0117]    When control arm  43  is rotated counterclockwise, stud  44   c  of control arm  43  will push guide bar  68  upwards towards control arm  42  guided by guide spacers  64   a.  Once the rotation is completed, blocker  66  covers hole  42   a  of control arm  42  to prevent access with handle  220 . Guide bar  68  is also positioned to prevent control arm  42  from rotating clockwise by blocking stud  44   a  of control arm  42 . From this point, control arm  43  must be rotated clockwise first before control arm  42  can rotate clockwise. After control arm  43  is rotated clockwise, spring end  74   a  pushes against pivot rod  71  so that guide bar  68  is pulled downwards to allow movement for control arm  42 . 
         [0118]    As best illustrated in  FIGS. 6 and 23 , tank side  11   c  is bolted to support bars  15   b  and  15   c  through threaded holes. Control shafts  41   a  and  41   b  are aligned and fitted over ends  60   d  of drive shaft  60  and end  363   b  of drive shaft  363 , respectively. Tank side  11   b  is bolted to support bars  14   a  and  14   c  through threaded holes. Tank side  11   d  is bolted to support bars  14   b  and  14   d  through threaded holes. Tank sides  11   a,    11   b,    11   c,  and  11   d  are bolted together at bolting nuts  37 . As best illustrated in  FIG. 5 , rectangular support bar  408  is bolted to tank side  11   b  and  11   d  at points  79  and  78 , respectively. As best illustrated in  FIG. 24 , cylindrical rods  419  are bolted to tank side  11   d  at points  420   a  and  420   b  and to corresponding points on tank side  11   b.    
         [0119]    Interlocking control assembly cover  53  is aligned and secured to threaded cover spacers  30  with washers and bolts. As illustrated in  FIG. 9 , the front end of rod  71  will extend into slot  53   a  and the front end of pivot rod  72  will extend through slot  53   b  of cover  53 . The front ends of spacer guides  64   a  and  64   b  will extend out of holes  53   c  and  53   d,  respectively, and fastened with retaining washers. The slotted openings for control shafts  41   a  and  41   b  can be accessed through holes  53   e  and  53   f,  respectively, of cover  53 . 
         [0120]    Vacuum interrupter switch  5  is operated with handle  220  ( FIGS. 44-46 ) by inserting the slotted end of handle shaft  220   a  into the slotted openings of either control shafts  41   a  or  41   b  and turning clockwise or counterclockwise. 
         [0121]    The specific components illustrated in the drawings and described in the specification are presently preferred components, and there is no intention to limit the scope of the invention to an assembly using these specific components to achieve the intended result. It is recognized that those skilled in the art may be able to change or modify the specifically described hardware, and that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by appended claims. It is accordingly intended that the claims be interpreted as broadly as possible in light of the prior art, and that the full advantage of the Doctrine of Equivalents be employed in such interpretation.