Patent Publication Number: US-11387059-B2

Title: High voltage vertical break disconnect switch with planetary gear reduction switch drive mechanism

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application No. 63/114,167 filed Nov. 16, 2020, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates generally to a vertical break disconnect switch for high voltage applications and, more particularly, to an extra high voltage (EHV) vertical break disconnect switch. 
     In electric power systems, high voltage disconnect switches are employed to isolate transmission lines and high voltage electrical apparatus to permit the inspection or repair of such apparatus or redirect power or other reasons. A common outdoor vertical break disconnect switch drive mechanism includes a post insulator connected to a current carrying blade through a space linkage. Typically, when the switch is opening the insulator is caused to rotate through 100 degrees about its longitudinal axis while the switch blade rotates about its longitudinal axis and then the switch blade is caused to move about a hinge mounted at a proximal end of the blade causing the blade to pivot about its proximal end through about 90 degrees in the vertical direction and thereby provide an air gap across the open switch. The rotating post insulator is solidly connected to an above-mounted single-piece crank shaft. The crank shaft drives a link connecting to the switch blade assembly. High voltage vertical break disconnect switches such as, extra high voltage (EHV) air insulated disconnect switches have comparatively long blades which become heavy under thick ice condition greatly increasing the required power output from the switch&#39;s operator putting extra stress on the rotating post insulator. EHV switches are typically rated for handling voltages from 345 kV to 800 kV. 
     Such high voltage vertical break disconnect switches, including horizontally or vertically mounted high voltage vertical break switches, are characterized by the elongated switch blade when closing, to first swing about a stationary pivot at the proximal end of the blade, in a first switch closing operation and subsequently to rotate about its own axis in a second switch closing operation. A reverse operation of the switch takes place during opening. As such, a horizontally mounted vertical break disconnect switch blade when closing in the first switch closing operation first swings about the stationary pivot from a vertical orientation to a horizontal orientation, where an elongated blade contact portion or tip carried at the distal end of the switch blade comes into first contact with a break jaw stop of a break jaw assembly at an intermediate closing position of the switch. The switch blade then, in the second switch closing operation, rotates about its own longitudinal axis between the parting contact jaws, with the blade tip&#39;s side edges forcing the parting contact jaws to spread until desirably full contact with the oppositely disposed break jaws is accomplished in the final closing of the switch. The side edges of the blade contact portion or tip at full contact are typically about horizontal when in full contact with the contact fingers of the break jaws. A basic patent for such a high voltage vertical break switch is disclosed in U.S. Pat. No. 2,521,484, entitled “Electric Switch Whose Blade Swings and Twists”, by Frederick G. Schmidt, issued Sep. 5, 1950. Such a vertical break switch for very high voltage applications is disclosed in Cleaveland/Price Inc. Bulletin DB-06DP-A20, entitled “V2-CA Aluminum Vertical Break Disconnect Switch 500 kV-3000 A, which is incorporated herein by reference as though fully set forth. Cleaveland/Price Inc. is the assignee of the present invention. 
     Such a standard prior art vertical break disconnect switch includes linkage connecting the switch blade driven by a prime mover, such as, an electric motor or geared hand crank assembly rotating a perpendicular cylindrically-shaped insulator that is directly connected to a crank shaft mounted above the rotating insulator. An adjacent non-rotating perpendicular cylindrically-shaped insulator supports a live base assembly that includes the driven linkage connecting to the switch blade which is actuated by the rotating insulator. 
     It is therefore an object of the present invention to provide a high voltage vertical break disconnect switch such as, an extra high voltage (EHV) vertical break disconnect switch with a compact and economical drive mechanism that places reduced stress on the rotating perpendicular cylindrically-shaped insulator and power transmitting components between the prime mover and the switch crank component compared to prior art switches, particularly when under heavy thick ice conditions when opening or closing. 
     SUMMARY OF THE INVENTION 
     The object is achieved by the high voltage vertical break disconnect switch of the present invention having an improved drive mechanism for reducing the loads transmitted by the switch&#39;s drive components between the switch&#39;s operator, i.e., a prime mover such as a motor or geared hand crank assembly, and the switch&#39;s crank shaft mounted on top of the perpendicular rotating cylindrically-shaped insulator. This is accomplished by the introduction of a planetary gear reduction assembly into a modified crank shaft of the switch which requires replacing the prior art existing single piece crank shaft with a two-piece crank shaft. The planetary gear reduction assembly of the present invention includes a planetary gear reduction switch drive mechanism having at least one stage. In the case of a high voltage vertical break disconnect switch of the extra high voltage (EHV) type rated for voltages of greater than 500 kV, a two-stage planetary gear reduction switch drive mechanism of the present invention is preferred. In the case of a high voltage vertical break disconnect switch rated for voltages of 345 kV and lower, a single-stage planetary gear reduction switch drive mechanism of the present invention may be utilized. The linkage beyond the crank shaft that moves the blade between the open and closed positions is the same as the prior art standard arrangement for a standard prior art high voltage vertical break disconnect switch. 
     In the case of a high voltage vertical break disconnect switch of the extra high voltage (EHV) type, a two-stage planetary gear reduction switch drive mechanism is installed between the top of the rotating perpendicular cylindrically-shaped insulator to virtually surround in cooperating relationship the two-piece crank shaft, which is operatively attached to the rotating insulator. The two-stage planetary gear reduction switch drive mechanism is mounted in a live base assembly. The two-piece crank shaft has a lower shaft part and an upper shaft part. The lower shaft part of the two-piece crank shaft is solidly connected to the top of the rotating perpendicular cylindrically-shaped insulator, while the upper shaft part of the modified crank shaft is rotatable with respect to the lower shaft part by means of a secondary gear train of the two-stage planetary gear reduction. The top of the lower shaft part of the modified crank shaft operatively engages a sun gear connected as the input gear to a first stage planetary gear set. A first stage planet carrier assembly is rotated by means of the interaction of the input sun gear and a stationary first stage ring gear which is held from rotating by means of stationary insulator side plates of the live base assembly. A second stage sun gear is rigidly connected to the first stage planet carrier and is the input gear for the second stage. A second stage carrier is rotated by the interaction between the second stage sun gear and a second stage ring gear which is held stationary in the same manner as the first stage ring gear. The second stage planet carrier is solidly connected to the upper shaft part of the modified two-piece crank shaft which is the output of the gear train and used to drive the vertical break live base assembly linkage. The upper shaft part of the modified two-piece crank shaft accepts plates that creates a traditional crank component which is used to drive the vertical break linkage. 
     The standard prior art vertical break switch linkage is driven by the rotating perpendicular cylindrically-shaped insulator that is directly connected to the two-piece crank shaft of the present invention. The live base assembly is held stationary by a non-rotating perpendicular cylindrically-shaped insulator which supports the live base assembly that includes the live base assembly linkage which can be actuated by rotating the rotating insulator. 
     In the case of a high voltage vertical break disconnect switch rated for system voltages less than 345 kV, a single-stage planetary gear reduction switch drive mechanism is installed between the top of the rotating perpendicular cylindrically-shaped insulator to virtually surround in cooperating relationship the two-piece crank shaft, which is operatively attached to the rotating insulator. The single-stage planetary gear reduction switch drive mechanism is mounted in the live base assembly. The two-piece crank shaft as mentioned has a lower shaft part and an upper shaft part. The lower shaft part of the two-piece crank shaft is solidly connected to the top of the rotating perpendicular cylindrically-shaped insulator, while the upper shaft part of the modified crank shaft is rotatable with respect to the lower shaft part by means of a gear train of the single stage planetary gear reduction switch drive mechanism. The top of the lower shaft part of the modified crank shaft operatively engages a sun gear connected as the input gear to a single stage planetary gear set. A single stage planet carrier assembly is rotated by means of the interaction of the input sun gear and a stationary single stage ring gear which is held from rotating by means of stationary insulator side plates of the live base assembly. The single stage planet carrier is solidly connected to the upper shaft part of the modified two-piece crank shaft which is the output of the gear train and used to drive the vertical break live base assembly linkage. The upper shaft part of the modified two-piece crank shaft accepts plates that creates a traditional crank component which is used to drive the vertical break linkage. 
     These and other aspects of the present invention will be further understood from the entirety of the description, drawings and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the invention reference may be made to the accompanying drawings exemplary of the invention, in which: 
         FIG. 1  is a schematic partially cut away side-elevation view of an extra high voltage vertical break switch of the prior art shown in both the closed position and open position; 
         FIG. 2  is a schematic perspective view of the live base assembly in the configuration of the invention; 
         FIG. 3  is a schematic sectional elevation view of the live base assembly of the invention with a two-stage planetary gear reduction assembly mounted on the rotating perpendicular cylindrically-shaped insulator taken along the line ‘ 3 ’-‘ 3 ’ of  FIG. 2 ; 
         FIG. 4  is an exploded view of  FIG. 3 . 
         FIG. 5  is a schematic sectional elevation view of a single-stage planetary gear reduction assembly version of the invention; and, 
         FIG. 6  is an exploded view of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to  FIG. 1  showing the prior art, a high voltage vertical air break disconnect switch  10  in the electrically closed position and also in the electrically opened position, indicated by the curved arrow and dashed lines, is shown. The switch  10  includes a longitudinal beam  12  having a top  12   a  with three perpendicularly mounted post-type cylindrically-shaped insulators  13   a ,  13   b  and  14 . A first post insulator  13   a  and a second post insulator  13   b  are stationary and are mounted as shown in  FIG. 1 . The third post insulator  14  is rotatable and can be driven by a prime mover  36 , such as an electric motor with controls or a manual geared hand crank assembly having a prime mover drive shaft  16 , as well known in the art, operatively attached to the bottom  18  of the third post insulator  14 . 
     A line-terminal connection  20  and a stationary break-jaw contact assembly  22  are attached to the top  15  of the stationary first post perpendicular cylindrically-shaped insulator  13   a . The break-jaw contact assembly  22  may have U-shaped break-jaws, not shown in the drawings. An elongated movable switch-blade assembly  24  makes electrical contact with the stationary break-jaw contact assembly  22 , when the switch  10  is closed. The elongated movable switch-blade assembly  24  includes an elongated switch blade  26  which is pivotally mounted at its proximal end  30  to a hinge assembly  28 , for electrically opening and closing the high voltage vertical break disconnect switch  10 . The general details of this arrangement are apparent by reference to  FIG. 1 . The elongated switch blade  26  may be tubular for example. A switch blade contact portion, is arranged at a distal end  32  of the switch blade  26 , such as a relatively flat switch blade tip  34 , for contacting the U-shaped stationary break-jaw contact assembly  22 , when the switch  10  is in the electrically closed position, as shown in  FIG. 1 . 
     As shown in  FIG. 1 , the rotatable third post perpendicular cylindrically-shaped insulator  14  is capable of rotary operative motion about its longitudinal axis  23  for driving the switch-blade assembly  24  to mechanically interconnect the operation of the elongated movable switch-blade assembly  24  with the rotation of the rotatable third post insulator  14 . As mentioned, the switch  10  includes a prime mover, such as an electric motor or geared hand crank assembly  36 , shown in  FIG. 1  schematically as a box, for three phase group operation, for rotating the prime mover drive shaft  16  to cause the rotation of the third post perpendicular cylindrically-shaped insulator  14  to open and close the switch  10 , as is well known in the art. A drive shaft support bearing  25  is provided for supporting the prime mover drive shaft  16  and the rotatable third post insulator  14 , as shown in  FIG. 1 . 
     The hinge assembly  28  is provided with a blade hinge pivot point, which may be hinge shaft  38 ; the hinge assembly  28  in electrically conductive relationship with the elongated switch blade  26 . The switch-blade  26  is operatively attached at its proximal end  30  to the hinge shaft  38  which blade hinge pivot point is used for rotating the blade  26  to the open position as shown in  FIG. 1 . A crank assembly  40  at one end  40   a  operatively engages a movable link assembly  42  through pin  46 , which is rotated by the operating motion of the rotatable third post perpendicular cylindrically-shaped insulator  14 . The movable link assembly  42  is in operative arrangement with the hinge assembly  28  for rotating the elongated switch blade  26  from a closed electrically conductive position to an open electrically non-conductive position. The crank assembly  40  is connected at the other end  40   b  to a one piece crank shaft  50  supported by and substantially housed in a live base assembly  52 , as shown in  FIG. 1 , which is the prior art. The live base assembly  52  is mounted on and supported by stationary first post perpendicular cylindrically-shaped insulator  13   b , which as can be seen in  FIG. 1 , adjoins rotatable third post perpendicular cylindrically-shaped insulator  14 . The live base assembly  52  includes a straight unbent first side plate  54  and an oppositely disposed straight unbent second side plate  56 , not shown in  FIG. 1 . The crank assembly  40  is attached to the one piece crank shaft  50  as shown in  FIG. 1 . A spring counter balance tube assembly  48  is connected at one end  66  to a fixed pin  67  through the live base assembly  52  and at the other end  68  to spring counterbalance arm assembly  69 . The spring counter balance tube assembly  48  acts to counter balance the weight of the switch-blade assembly  24 . 
     Regarding the operation of the switch  10  during closing, the movement of the rotatable third post perpendicular cylindrically-shaped insulator  14  initially causes the one piece crank shaft  50  and the elongated movable switch-blade assembly  24  to rotate about the hinge axis  44 , through a predetermined angle ‘A’—from a vertical orientation to a horizontal orientation as shown in  FIG. 1 . During this movement, the switch  10  goes from the open electrically non-conductive position to an almost fully closed position, as indicated by the solid curved line with double arrows in  FIG. 1 , which is designated as angle ‘A’ of about 90°. This initial rotation results in the switch  10  being in a so-called intermediate closed position, not shown in the drawings, with the switch blade tip  34  entering the U-shaped stationary break-jaw contact assembly  22 —but the tip is at a non-horizontal orientation between the jaw stationary contacts—and thus is not yet in the fully electrically closed position with the jaw stationary contacts, not shown. In the second switch closing operation, instead of the switch-blade assembly  24  rotating about the hinge axis  44 , the switch-blade assembly  24  rotates about its own longitudinal axis  27  to the fully closed position as shown in  FIG. 1 . 
     The horizontal vertical break switch  10  of prior art as described thus far is conventional and well known in the industry. As shown in  FIG. 2 , the live base assembly  52  of the present invention includes a first side plate  54  and an oppositely disposed parallel second side plate  56 , that have been modified from the side plates of the prior art live base assembly which are straight and not bent. This modified form of the side plates of the prior art live base assembly results in the live base assembly  52  of the present invention having a wide section  52   a  and a narrow section  52   b , as shown in  FIG. 2 , instead of the side plates having a uniform width of separation like the prior art live base assembly, not shown in the drawings. The modified live base assembly  52  also includes a top plate  58  and a bottom plate  62  which are positioned between the first and second side plates  54 ,  56  in the wide section  52   a  as shown in  FIG. 2 . As shown in  FIG. 3 , the bottom plate  62  is provided with a bottom plate crank shaft aperture  64 . The top plate  58  is provided with a top plate crank shaft aperture  60 . The narrow section  52   b  of live base assembly  52  is configured to carry a switch blade proximal end contact assembly  33  proximate the hinge assembly  28 , for provided electrical connection to the proximal end  30  of the switch blade  26  as shown in  FIG. 1 . Also, as shown in  FIG. 3 , the improvement of the present invention provides a planetary gear reduction assembly  65  housed within the wide section  52   a  of the modified live base assembly  52 . The planetary gear reduction assembly  65  includes a planetary gear reduction switch drive mechanism having at least one stage. A stage may include a stationary ring gear and a rotatable carrier assembly with planet gears. As shown in  FIGS. 3 and 4 , an embodiment for a high voltage vertical break disconnect switch of the extra high voltage (EHV) type, having a two-stage planetary gear reduction switch drive mechanism  70  in place of the prior art one piece crank shaft  50  is provided. This embodiment of the invention can be seen in  FIG. 3  showing the components of the two-stage planetary gear reduction switch drive mechanism  70  with an associated two-piece crank shaft assembly  72 , which are mounted between a plate  19  of rotatable third post insulator  14  and the crank assembly  40 . The two-piece crank shaft assembly  72  is coaxially aligned with and in operational rotational relationship with the rotatable perpendicular cylindrically-shaped insulator  13   a . The linkage beyond the crank assembly  40 , that moves the switch blade  26  between the open and closed positions is the same as the prior art arrangement already described. As can be seen in  FIGS. 3 and 4 , the two-stage planetary gear reduction switch drive mechanism  70  circumferentially surrounds a substantial portion of the two-piece crank shaft assembly  72 . The two-piece crank shaft assembly  72  includes a lower shaft part  74  which is solidly connected to plate  19  of the rotatable third post perpendicular cylindrically-shaped insulator  14 . The lower crankshaft part  74  has a central recess  75 , as can be seen in  FIG. 3 , for receiving a lower crankshaft part engagement portion  77  of the upper crankshaft part  76 . An upper crankshaft part support bearing  79  is operatively arranged proximate the central recess  75 , as shown in  FIG. 3 , for rotatably supporting the lower crankshaft part engagement portion  77 . The lower crankshaft part engagement portion  77  is rotatable within the central recess  75 . An upper shaft part  76  of the two-piece crank shaft assembly  72  is turned by means of a second planetary gear set  78  of the two-stage planetary gear reduction switch drive mechanism  70 . The lower shaft part  74  of the two-piece crank shaft assembly  72  has a first stage sun gear  80  connected to it as the input gear which engages with a first stage planetary gear set  82  as shown in  FIG. 4 . The first stage planetary gear set  82  and the second stage planetary gear set  78 , each include eight planet gears  84 , for example. The first stage planetary gear set  82  is turned by the interaction or engagement with the first sun gear  80 , i.e., the input gear, and a stationary first stage ring gear  86 . The stationary first stage ring gear  86  is held fixed relative to plates  58  and  62  by bolting. Plates  58  and  62  are held from turning by stationary insulator oppositely disposed side plates  56  and  54  of the live base assembly  52 , as can be discerned from  FIGS. 2 and 3 . The first stage planetary gear set  82  is nested within the stationary first stage ring gear  86  as can be seen by reference to  FIGS. 3 and 4 . Within the center of the first stage planetary gear set  82  is a first stage planet carrier  90  configured to carry the first stage planetary gear set  82  shown on  FIG. 4 . 
     In this embodiment, a second stage sun gear  92  is rigidly connected to the first stage planet carrier  90  and is driven by the first stage planetary gear set  82 . The second stage sun gear  92  is the input gear for the second stage planetary gear set  78 . The second stage planetary gear set  78  is turned by the interaction or engagement of the second stage sun gear  92 , i.e., the input gear, and a stationary second stage ring gear  96  which is held stationary in the same manner as the first stage ring gear  86 . Within the center of the second stage planetary gear set  78  is a second stage planet carrier  94  configured to carry the second stage planetary gear set  78 . The upper shaft part  76  of the two-piece crank shaft assembly  72  is solidly connected to the second stage planet carrier  94  and is the output of the two-stage planetary gear reduction switch drive mechanism  70 . The upper shaft part  76  is part of the second stage planetary gear set  78  and is the gear reduction output. 
     The lower shaft part  74  of the two-piece crank shaft assembly  72  is operably connected to the first stage sun gear  80  by cross pin  100 . As the lower shaft part  74  of the two-piece crank shaft assembly  72  is caused to rotate by perpendicular cylindrically-shaped insulator  14  connected to the prime mover  36  the first stage sun gear  80  actuates first stage planetary gear set  82  of the two-stage planetary gear reduction switch drive mechanism  70 . 
     This embodiment of the two-stage planetary gear reduction switch drive mechanism  70  with an associated two-piece crank shaft assembly  72  provides for the rotatable third post insulator  14  and the lower shaft part  74  of the two-piece crank shaft assembly  72  to rotate multiple times while the upper shaft part  76  of the two-piece crank shaft assembly  72  rotates about 180 degrees. This particular arrangement has a 9:1 gear reduction. The rotatable third post insulator  14  rotates about 4.5 times to rotate the crank assembly  40  through 0.5 rotations, thus providing reduced stress on the rotating perpendicular cylindrically-shaped insulator  14  and power transmitting components between prime mover  36  and the switch crank component compared to prior art switches, particularly under heavy thick ice conditions when opening or closing. 
     In a second embodiment of the invention, applicable to the case of a high voltage vertical break disconnect switch  10  rated for voltages of 345 kV and lower, a single-stage planetary gear reduction switch drive mechanism  98  of the present invention may be utilized as shown in  FIGS. 5 and 6 , instead of a two-stage mechanism. Like reference numerals are used for the present embodiment as were used for the first embodiment and represent the same or similar elements for this embodiment. This embodiment of the invention as can be seen in  FIG. 6  shows the components of the single-stage planetary gear reduction switch drive mechanism  98  with an associated two-piece crank shaft assembly  72 . As can be seen in  FIGS. 5 and 6 , the single-stage planetary gear reduction switch drive mechanism  98  circumferentially surrounds a substantial portion of the two-piece crank shaft assembly  72 . The two-piece crank shaft assembly  72  includes a lower shaft part  74  which is solidly connected to the plate  19  of the rotatable third post perpendicular cylindrically-shaped insulator  14 . The lower crankshaft part  74  has a central recess  75 , as can be seen in  FIG. 5 , for receiving a lower crankshaft part engagement portion  77  of the upper crankshaft part  76 . An upper crankshaft part support bearing  79  is operatively arranged proximate the central recess  75 , as shown in  FIG. 5 , for rotatably supporting the lower crankshaft part engagement portion  77 . The lower crankshaft part engagement portion  77  is rotatable within the central recess  75 . An upper shaft part  76  of the two-piece crank shaft assembly  72  is connected to the single-stage planetary gear set  78  of the single-stage planetary gear reduction switch drive mechanism  98 . As shown in  FIG. 6 , the lower shaft part  74  of the two-piece crank shaft assembly  72  has a single stage sun gear  80  connected to it by cross pin  100  and is the input gear which engages with the single-stage planetary gear set  78 . The single-stage planetary gear set  78  includes eight planet gears  84 , for example. The single-stage planetary gear set  78  is turned by the interaction or engagement with the single-stage sun gear  80 , i.e., the input gear, and a stationary single stage ring gear  86 . The stationary single stage ring gear  86  is held fixed relative to plates  58  and  62  by bolting. Plates  58  and  62  are held from turning by stationary insulator oppositely disposed side plates  56  and  54  of the live base assembly  52 , as can be discerned from  FIGS. 2 and 5 . The single-stage planetary gear set  78  is nested within the stationary single stage ring gear  86  as can be seen by reference to  FIGS. 5 and 6 . 
     Within the center of the single stage planetary gear set  78  is a single stage planet carrier  90  configured to carry the single stage planetary gear set  78 . The upper shaft part  76  of the two-piece crank shaft assembly  72  is solidly connected to the single stage planet carrier  90  and is the output of the single-stage planetary gear reduction switch drive mechanism  98 . The upper shaft part  76  is part of the single stage planetary gear set  78  and is the gear reduction output. 
     As the lower shaft part  74  of the two-piece crank shaft assembly  72  is caused to rotate by insulator  14  connected to the prime mover  36 , the single stage sun gear  80  actuates the single stage planetary gear set  78  of the single-stage planetary gear reduction switch drive mechanism  98 . 
     This embodiment of the single-stage planetary gear reduction switch drive mechanism  98  with an associated two-piece crank shaft assembly  72  provides for the rotatable third post insulator  14  and the lower shaft part  74  of the two piece crank shaft assembly  72  to rotate multiple times while the upper shaft part  76  of the two piece crank shaft assembly  72  rotates about 180 degrees. This particular arrangement has a 3:1 gear reduction. The rotatable third post insulator  14  rotates about 1.5 times to rotate the crank assembly  40  through 0.5 rotations, thus providing reduced stress on the rotating insulator  14  and power transmitting components between prime mover  36  and the switch crank component compared to prior art switches, particularly under heavy thick ice conditions when opening or closing. 
     LIST OF REFERENCE NUMERALS 
     
         
         
           
               10  high voltage air break disconnect switch 
               12  longitudinal beam 
               12   a  top of  12   
               13   a  stationary 1 st  post perpendicular cylindrically-shaped insulator 
               13   b  stationary 2 nd  post perpendicular cylindrically-shaped insulator 
               14  rotatable 3 rd  post perpendicular cylindrically-shaped insulator 
               15  top of  13   a    
               16  motor drive shaft 
               18  bottom of  14   
               19  plate of  14   
               20  line-terminal connection 
               22  U-shaped stationary break-jaw contact assembly 
               23  longitudinal axis of  14   
               24  elongated movable switch-blade assembly 
               25  drive shaft support bearing assembly 
               26  elongated switch blade 
               27  longitudinal axis of  24   
               28  hinge assembly 
               30  proximal end of  26   
               32  distal end of  26   
               33  switch blade proximal end contact assembly 
               34  switch blade tip 
               36  prime mover, motor or geared hand crank assembly 
               38  hinge shaft 
               40  crank assembly 
               40   a  one end of  40   
               40   b  other end of  40   
               42  movable link assembly 
               44  hinge axis 
               46  pin 
               48  spring counter balance tube assembly 
               50  one piece crank shaft of prior art 
               52  live base assembly 
               52   a  wide section of  52   
               52   b  narrow section of  52   
               54  first live base assembly side plate 
               56  second live base assembly side plate 
               58  top plate of live base assembly 
               60  top plate crank shaft aperture 
               62  bottom plate of live base assembly 
               64  bottom plate crank shaft aperture 
               65  planetary gear reduction assembly 
               66  one end of  48   
               67  fixed pin 
               68  the other end of  48   
               69  counterbalance arm assembly 
               70  two-stage planetary gear reduction switch drive mechanism 
               72  two piece crank shaft assembly 
               74  lower shaft part of  72   
               75  central recess 
               76  upper shaft part of  72   
               77  lower crankshaft part engagement portion 
               78  2 nd  stage or single stage planetary gear set 
               79  upper crankshaft part engagement portion 
               80  first stage or single stage sun gear 
               82  first stage planetary gear set 
               84  planet gears 
               86  stationary first stage or single stage ring gear 
               90  first stage planet carrier or single stage planet carrier 
               92  second stage sun gear 
               94  second stage planet carrier 
               96  stationary second stage ring gear 
               98  single-stage planetary gear reduction switch drive mechanism 
               100  cross pin 
           
         
       
    
     Of course variations from the foregoing embodiments are possible without departing from the scope of the invention.