Abstract:
A contact portion switch device of a circuit breaker which is capable of guaranteeing reliable operation by restraining distortion of each construction part in the operation of the circuit breaker and permitting an easy installation of an additional part for performing multifunction is disclosed. A switch lever installed in order to rotate between a penetration position and a cut-off position of a fixed contact portion and a movable contact portion, a cut-off spring combined to the switch lever, an operating wheel installed on the side of the switch lever so as to be rotational, an operating wheel for rotating the operating wheel, an operating arm installed on the side of the operating wheel so as to be rotational, an electric link interposed between the operating wheel and operating arm, a penetration spring combined to the operating arm, a trip arm combined to a rotating shaft of the switch lever, a trip latch for preventing the switch lever from rotating to the cut-off position, a penetration latch installed on the side of the operating wheel, and a transmission part placed between the operating arm and switch lever is also disclosed.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a vacuum circuit breaker, in particular to a switching mechanism of a vacuum circuit breaker. In more particular, the present invention relates to a switching mechanism of a vacuum circuit breaker which is capable of guaranteeing the credibility of its operation by restraining distortion of each component and installing additional components easily in order to perform multifunction. 
     2. Description of the Prior Art 
     Generally, a circuit breaker is for switching an electric circuit in order to protect a load unit or a load line from abnormal current caused by abnormal situations such as a short circuit occurrence on electric circuits from a power plant or a substation to an electric facility of a consumer, the circuit breaker is divided into an AC circuit breaker and a DC circuit breaker according to an applied line, and it is divided into a vacuum circuit breaker and a gas circuit breaker according to an arc shielding medium when the contact is switching. 
     Generally, inside of the circuit breaker is vacuum or is filled with an insulating material, and an arc-extinguishing unit for shielding arc generated in the switching operation of a fixed contactor and a movable contactor installed in the vacuum area or insulating material filled area is disposed in the circuit breaker. A switching mechanism for providing driving force is connected to an extended end of the movable contactor exposed-installed from the sealed area in order to contact or separate the movable contactor to/from the fixed contactor. 
     The conventional switching mechanism for the vacuum circuit breaker will now be described with reference to accompanying FIG.  1 . The construction and operation of the conventional switching mechanism for the vacuum circuit breaker is referable in the U.S. Pat. No. 5,140,117. 
     In the conventional switching mechanism for the vacuum circuit breaker, the end portion of a switch lever  111  having a long plate shape is connected to a movable contact portion  105 , the switch lever  111  is installed centering around a first rotating shaft  113  so as to be movable to a turn-ON position or turn-OFF position where the movable contactor  105  and fixed contactor  103  are mutually contacted or separated in order to contact or separate the movable contactor  105  to/from the fixed contactor  103 . A lever driving unit  121  comprises a cut-off spring  117  coupled to the switch lever  111  in order to drive the switch lever  111 . One end portion of an arm  115  is coupled to the other end portion of the switch lever  111 , the other end portion of the arm  115  is contacted to the lever driving unit  121 . A slave roller  116  is coupled to a free end portion as the other end portion of the arm  115  so as to be rotatable in order to be transferred by contacting a cam. The cut-off spring  117  is combined to the first rotation shaft  113  with a certain distance in order to press the switch lever  111  elastically to the turn-OFF position. 
     Hereinafter, the structure of the lever driving unit  121  will now be described in detail. 
     Conventionally, the lever driving unit  121  of the switching mechanism for the circuit breaker comprises a second rotating shaft  124  fixed on a base plate  121   a . An end portion of a turn-on spring  135  is combined to the second rotating shaft  124 . The cam  129  is coupled to the rotating shaft  131  coupled to the other end portion of the turn-on spring  135  so as to be rotatable, and performs a relative motion by contacting mutually to the slave roller  116 . A supporting unit  123  is coupled to the rotating shaft  131  so as to be rotatable in order to rotate centering around the turn-on spring  135 . A turn-on latch  137  is coupled to the side of the cam  129  so as to be rotational in order to make the turn-on spring  135  maintain an extension state by restraining the rotation of the cam  129 . A trip latch  139  is installed on the free end portion of the supporting unit  123  in order to prevent the supporting unit  123  from rotating by being pressed by the cut-off spring  117 . A stopper  127  is installed on the side of the trip latch  139  in order to restrain the rotation of the supporting unit  123  by contacting mutually with the supporting unit  123 . 
     The cam  129  is installed so as to rotate centering around the rotating shaft  131  projected from the plate surface of the supporting unit  123 , and the other end portion of the turn-on spring  135  is combined to the side of the cam  129  in order to rotate the cam  129 . 
     And, a stopper pin  133  is protrusively disposed on the side surface of the cam  129 , a roller  134  is installed on the stopper pin  133  so as to be rotational in order to contact the free end portion of the turn-on latch  137 . 
     Hereinafter, the operation of the conventional switching mechanism for the vacuum circuit breaker will now be described. 
     First, in order to make the movable contactor contact to the fixed contactor  103 , the turn-on  137  rotates in order to separate from the roller  134  of the stopper pin  133  of the cam  129 . 
     By the above said operation, the turn-on latch  137  is separated from the roller  134 , as depicted in FIG. 2, at the same time the cam  129  rotates to the clockwise direction by the tensile force of the turn-on spring  135 . 
     According to the rotation of the cam  129 , the slave roller  116  is pressed so as to separate from the rotating shaft  131  of the cam  129 , accordingly the switch lever  111  rotates toward the turn-ON position centering around the first rotating shaft  113 . 
     According to the rotation of the switch lever  111 , the fixed contactor  103  and movable contactor  105  are contacted each other, the cut-off spring  117  is elastically energized by being extended according with the rotation of the switch lever  111 . 
     On the contrary, in order to make the movable contactor  105  separate from the fixed contactor  103 , the trip latch  139  rotates in order to separate from the end portion of the supporting unit  123 . 
     According to the rotation, when the trip latch  139  is separated from the supporting unit  123 , as depicted in FIG.2, the switch lever  111  rotates to the counter clock-wise direction centering around the first rotating shaft  113  by the tensile force of the cut-off spring  117 . According to this, the supporting member  123  rotates temporarily centering around the second rotating shaft  124 , but the rotation of the supporting unit  123  is stopped by contacting to the stopper  127 . 
     Accordingly, according to the rotation of the switch lever  111 , the movable contactor  105  is separated from the fixed contactor  103 . 
     However, in the conventional vacuum circuit breaker, the supporting unit rotates centering around the second rotating shaft by the tensile force of the cut-off spring, and the rotation is stopped by contacting with the stopper  127  with an impact on the both supporting unit  123  and stopper  127 . When the operation is performed repeatedly, the distortion and separation of the construction parts including the cam can occur due to the impact force caused by the contact between the supporting unit  123  and stopper  127 . And, it may causes below problems. 
     First, the credibility of the apparatus can be lower because the turn-on or 
     Turn-off operation may not be performed smoothly due to the distortion of the construction parts caused by the impact force. 
     Second, in the conventional vacuum circuit breaker, the eccentric-installed switch lever and arm supported by the cut-off spring and the cam supported by the turn-on spring are suspended on the lower portion of the each spring, and the fixed supporting position for each spring is same as upper position. 
     Moreover, the switch lever is made with a steel plate having long length and the cam is made with the steel plate having long width, the gravity of the switch lever and cam have a bad effect on the compression/extension operation of the springs for contacting or separating the movable contactor to or from the fixed contactor. In particular, because the conventional vacuum circuit breaker uses a two link having the switch lever and operating arm, the gravity of the two link is more concentrated on the cut-off spring than the gravity of a multi link. 
     Third, when there is a need to add a new function, additional installation is difficult because the lever operating unit comprising the two springs and cam is constructed as the one assembly unit. 
     Fourth, the life span of the circuit breaker can lower due to over-energizing of the turn-on spring because there is no detecting means for detecting the energizing completion of the turn-on spring when the turn-on spring is elastically energized. 
     Fifth, in the conventional vacuum circuit breaker, there is no displaying means for displaying the energizing completion state or energizing energy exhaustion state of the turn-on spring, accordingly it is inconvenient for a user to use the circuit breaker. 
     Sixth, there is no displaying means for displaying the turn-ON or turn-OFF state of the main circuit, accordingly it is inconvenient for the user to use the circuit breaker. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a switch device for a vacuum circuit breaker which is capable of solving the above-mentioned problems. 
     The first problem of the conventional technology can be solved by providing the switch device for the vacuum circuit breaker according to the present invention which does not comprises a stopper restricting the rotation of a supporting unit. 
     The second problem of the conventional technology can be solved by &lt;providing the switching mechanism for the vacuum circuit breaker which comprises a first and a second spring for providing power for contacting movable contactor the fixed contactor or separating the movable contactor from the fixed contactor, wherein the first spring being providable the power for contacting the movable contactor to the fixed contactor when it is elastically energized, and the second spring being providable the power for separating the movable contactor from the fixed contactor when it is elastically energized, each of the first and second spring having one end portion being a operating point for providing the power and the other end portion for providing a supporting point to be extended or compressed, each of said other end portions of the first and second spring being placed to be vertically opposite; 
     a plurality of link means for providing the power provided from the first spring or the second spring to the movable contactor; and a spring energizing means for energizing at least one spring among the first and second spring. 
     The third problem of the conventional technology can be solved by providing the vacuum circuit breaker according to the present invention which is capable of installing easily a new function mean such as a displaying mean for displaying an original position return state or extension state of the turn-on spring or displaying a turn-ON (ON) state or turn-OFF (OFF) state of the circuit breaker. 
     The fourth problem of the conventional technology can be solved by providing the vacuum circuit breaker according to the present invention which comprises a driving wheel including a gear portion for receiving the power on the outer circumference and a gearless portion for detecting the energizing completion of the turn-on spring on the outer circumference. 
     The fifth problem of the conventional technology can be solved by providing the vacuum circuit breaker comprising a display plate including a display unit which is co-axially connected to the rotating shaft of the driving arm in order to rotate according to the rotation of the driving arm and display the energizing state or energizing energy exhaustion state of the spring on the front plate of the vacuum circuit breaker, and a see through window installed on the front surface of the vacuum circuit breaker in order to watch the display unit of the display plate. 
     The sixth problem of the present invention can be solved by providing the vacuum circuit breaker comprising a display plate including a display unit which is co-axially connected to the rotating shaft of the switch lever in order to rotate according to the rotation of the switch lever and display the turn-ON or turn-OFF state of the main circuit on the upper surface, and a see through window installed on the front surface of the vacuum circuit breaker in order to watch the display unit of the display plate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view illustrating the conventional switch device of the vacuum circuit breaker. 
     FIG. 2 is a side view illustrating a turn-ON state of the conventional switch device of the vacuum circuit breaker. 
     FIG. 3 is a front view illustrating a switch device of a vacuum circuit breaker according to the embodiment of the present invention. 
     FIG. 4 is a front view illustrating a turn-OFF state of the switch device of the vacuum circuit breaker according to the embodiment of the present invention. 
     FIG. 5 is a front view illustrating a turn-ON state of the switch device of the vacuum circuit breaker according to the embodiment of the present invention. 
     FIG. 6 is a front view illustrating an extended state of a penetration spring and a cut-off spring used in the switching mechanism of the vacuum circuit breaker according to the embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, the embodiments of a switching mechanism of a vacuum circuit breaker according to the present invention will now be described with reference to accompanying drawings. 
     The present invention can be embodied many ways, hereinafter the preferred embodiment will now be described. 
     FIG. 3 is front view illustrating an initial state of the switching mechanism of the vacuum circuit breaker according to the embodiment of the present invention. Herein, the initial state means a main circuit is turned-off state, in other words, a movable contactor and a fixed contactor are separated, a turn-ON spring and a cut-off spring are not elastically energized. 
     As depicted in FIG. 3, the switching mechanism according to the embodiment of the present invention comprises a switch lever  7  installed so as to be rotational to a switch-ON position or switch-OFF position where a fixed contactor  3  of a arc-extinguishing unit  1  contacts or separates to/from a movable contact portion  5 . The end of a cut-off spring  13  for providing the energized elastic force is contacted to the upper portion adjacent to the length-directional center portion of the switch lever  7  in order to make the switch lever  7  rotate to the switch OFF position. 
     And, the switch lever  7  is installed so as to be rotational centering around a rotating shaft  9  which length-directionally penetrates the side portion of the switch lever  7 , the end of a connection link  11  connected to the movable contactor  5  is coupled to the end portion of the switch lever  7  placed opposite to the rotating shaft  9  in order to perform a relative motion. 
     A first movable supporting member  15  is coupled to the other end of the cut-off spring  13  on which a first stopping portion  21  is formed so as to adjust the Elastic force of the cut-off spring  13 , and a first recess portion  15   a  is formed inside of the first movable supporting member  15  for containing the first stopping portion  21  so as to perform pivot. 
     A first male threaded portion  16  is formed on the outer circumference of the first movable supporting member  15 , and is partly or totally meshed or separated to/from a first female threaded portion  19  formed on the inner circumference of a first fixed supporting member  17  placed corresponding to the first male threaded portion  16 . Accordingly, the elastic force of the cut-off spring  13  can be adjusted because the first movable supporting member  15  can move along the axial line corresponding to the first fixed supporting member  17 . 
     Meanwhile, a driving wheel  33  is installed so as to be rotational centering around a rotating shaft  35  placed parallel to the rotating shaft  9  of the switch lever  7  to the axial line direction. 
     A geared portion  36  having a tooth formed with a predetermined portion is formed on the outer circumference of the driving wheel  33 , and a gearless portion  38  having a arch shape is formed on the outer circumference of the driving wheel  33 . 
     And, an driving pole  39  is installed on one side position of the driving wheel  33  for rotating the driving wheel  33  for making move the driving wheel  33  as much as the one teeth interval by meshing with the teeth of the geared portion  36 , and a reverse rotation restraining pole  43  is installed on the other side position of the driving wheel  33  in order to permit the clock-wise direction rotation of the driving wheel  33  by meshing with the tooth of the driving wheel  33  and at the same time restrain the counter clock-wise direction rotation of the driving wheel  33 . 
     A rotating shaft of the driving pole  39  is connected to the rotating shaft  41  a of an driving motor  41  for rotating the driving pole  39  through a power transmission means such as a crank shaft (not-shown) or a speed and torque transformable means such as a transmission. 
     Meanwhile, the other embodiment such as transmitting the power of the motor  41  to the driving wheel  33  through a gear instead of the driving pole  39  is possible. In addition, in order to make the turn-on spring energize elastically by a manual operation instead of the driving motor  41 , it is possible in the other embodiment to install a handle shaft its end is exposed to a front plate (not shown) of the vacuum circuit breaker and the other end is contacted to the driving pole  39 . Herein, a handle (not shown) is combined to the end of the handle shaft exposed on the front plate of the vacuum circuit breaker in order to provide the driving force. In addition, combining the manual operation embodiment with the embodiment using the gear as the power transmission means to the driving wheel  33  is possible. 
     Meanwhile, a turn-on cam  45  is coaxially connected to the rotating shaft  35  of the driving wheel  33  so as to rotate integrally with the driving wheel  33 . A turn-on latch  47  is installed on one side position deviated from the trajectory of the turn-on cam  45  being rotatable in order to maintain the energizing state of the turn-on spring  23  by preventing the rotation of the turn-on cam  45  and driving wheel  33  when the energizing of the turn-on spring  23  is completed. A rotation restraining roller  48  is installed rotatable by using the rotating shaft  47   a  of the turn-on latch  47  as the rotating shaft and it rotates to the position permitting the rotation of the cam  45  by releasing the contact with the cam  45  or the contact position with cam  45  in order to restrain the further rotation of the cam  45  when the energizing of the spring is completed. 
     The turn-on latch  47  rotates to the same direction of the rotation restraining roller  48  by being coaxially connected to the rotation straining roller  48 , and transmits the rotating force to the rotation restraining roller  48 . 
     In order to provide the rotating force to the turn-on latch  47 , a turn-on solenoid  49  is placed on the position where the turn-on latch  47  is pushed and is rotated. 
     The end of a link  55  is coupled to the turn-on cam  45  with a predetermined distance from the rotation shaft  35  so as to perform the relative motion with the turn-on cam  45 . The other end of the link  55  is coupled to the end of the driving arm  57 , the driving arm  57  can rotate to the clock-wise or counter clock-wise direction centering around the rotating shaft  57   a  placed parallel to the rotating shaft  35  of the driving wheel  33  correspondingly with the rotation of the driving wheel  33 . 
     In other words, the link  55  is placed between the driving wheel  33  and driving arm  57 , and transmits the power from the driving wheel  33  to the driving arm  57 . 
     Meanwhile, the other end of the driving arm  57  is coupled to the end of the turn-on spring  23 . The turn-on spring  23  rotates the switch lever  7  to the switch-ON position, and at the same time provides the driving force for making the cut-off spring  13  energize elastically. 
     In the meantime, a second movable supporting member  25  is coupled to the other end of the turn-on spring  23  in order to adjust the elastic force of the turn-on spring  23 . 
     A second stopping portion  31  is formed on the other end of the turn-on spring  23 , and a second recess portion  25   a  is formed inside of the second movable supporting member  25  in order to receive-support the second stopping portion  21  so as to perform the pivot. 
     And, a second male threaded portion  26  is formed on the outer circumference of the second movable supporting member  25 . A second female threaded portion  29  corresponding to the second male threaded portion  26  is formed on the inner circumference of the second fixed supporting member  27 , the second movable supporting member  25  is fastened or unfastened by the second male female threaded portion  29 , accordingly the second movable supporting member  25  partially or totally coupled or separates to/from the second fixed supporting member  27 . 
     The second movable supporting member  25  adjusts the elastic force of the turn-on spring  23  by moving along the axial line corresponding to the second fixed supporting member  27  after receiving the end of the turn-on spring  23  in order to perform the pivot and be stopped-fixed along the axial line. 
     Meanwhile, a stopping protrusion  51  is protrusively formed adjacent to the rotating shaft  47   a  of the turn-on latch  47 . A turn-on latch locking bar  53  is installed on the portion corresponding to the stopping protrusion  51 , the turn-on latch locking bar  53  restrains or permits the rotation of the turn-on latch  47  by contacting or separating to/from the stopping protrusion  51  by being rotated by the arm  59  rotating to the clock-wise direction. 
     In more detail, the turn-on latch locking bar  53  comprises a body having a semicircle cross-sectional shape and a protruded portion to be contactable with the arm  59 . Accordingly, when the vacant semicircle cross-sectional portion of the body is opposite to the stopping protrusion  51 , the turn-on latch  47  is permitted to rotate to the clock-wise direction, when the remained semicircle cross-sectional portion of the body is opposite to the stopping protrusion  51 , the rotation of the turn-on latch  47  is restrained. 
     The arm  59  is coaxially connected to the rotating shaft  57   a  of the driving arm  57 , and rotates to the clock-wise direction centering around the rotating shaft  57   a  of the driving arm  57 . One end of the driving arm  59  is contacted to a returning spring  60  for returning the arm  59  to the original position, and the other end of the driving arm  59  opposing in length direction to the one end of the driving arm  59  is coupled to a third link  69 . 
     In order to restrain the rotation of the driving arm  59 , a stopping pin portion  58  is protruded from a base surface of the driving arm  57 , one end of the arm  59  corresponding to the stopping pin portion  58  has an arch-shaped portion in order to increase the contact area between the stopping pin portion  58 . 
     Meanwhile, a trip arm  61  for restraining the clock-wise rotation and permitting the counter clock-wise rotation is coaxially connected to the rotating shaft  9  of the switch lever  7  so as to rotate to the same rotation direction of the switch lever  7 . 
     The other end of the trip arm  61  extended from the one end connected to the rotating shaft  9  is connected to a power transmission means. The power transmission means comprises at least three link means, is placed between the driving arm  57  and switch lever  17 , provides the elastically energized force of the penetration spring  23  or the elastically energized force of the cut-off spring  13  to the switch lever  7 , and rotates the switch lever to the switch-ON position or switch-OFF position. The power transmission means will now be described in detail. 
     The other end of the trip arm  61  is connected to a first link  63  so as to be rotational, a second link  65  is connected to the switch lever  7  so as to be rotational, the first and second link  63 ,  65  are arrayed centering around a connecting pin  67  so that the degree between the first and second link  63 ,  65  may have lower angle than 90°. The one end of a third link  69  is rotatably coupled to the free end of the arm  59  and the other end of a third link  69  is connected to the connecting pin  67 . 
     In the meantime, a roller  62  is coupled to the extended end of the trip arm  61  where the first link  63  is coupled so as to be rotational, the roller  62  contacts with the trip latch  71  installed so as to be rotational centering around a latch pin  72  without an impact, accordingly the rotation of the trip arm  61  is restrained. 
     The latch pin  72  is formed on the trip latch  71 , one end of the trip lever  73  placed so as to be rotational centering around the rotating shift  73   a  disposed on the side position of the latch pin  72  can contacts with the latch pin  72 . 
     Meanwhile, a trip solenoid  75  for making the trip latch  71  rotate the trip arm  61  and switch lever  7  to the switch OFF position by rotating the trip lever  73  is coupled to the other end of the trip lever  73 . 
     And, a first switch  77  is connected to the power supplying circuit of the operating motor  41  in order to cut off the power to the driving motor  41  on detecting idleness of the driving pole  39  when the gearless portion  38  of the driving wheel  33  contacts with the driving pole  39 . 
     The first switch  77  cuts off the power of the motor  41 , and at the same time turns on the power circuit to the turn-on solenoid  49 . 
     And, a second switch  79  is installed between the turn-on solenoid  49  and trip solenoid  75 , and one end of the second switch  79  is connected to the switch lever  7  in order to connect the power circuit to the turn-on solenoid  49  when the switch lever  7  is placed to the switch-OFF position by operating corresponding with the switching operation of the switch lever  7 . At the same time, the second switch  70  cuts off the power circuit to the trip solenoid  75 , when the switch lever is placed on the switch-ON position, it connects the power circuit to the trip solenoid  75 , and at the same time separates the power circuit to the penetration solenoid  49 . 
     Meanwhile, a displaying mean for displaying the energizing completion state or energizing energy exhaustion state of the turn-on spring  13  can be installed according to the embodiment of the present invention. 
     Herein, the displaying mean comprises a display plate (not shown) coupled to the driving arm  57  and rotating shaft  57   a  of the arm  59  among the link means rotating corresponding to the energizing completion state or energizing energy exhaustion state of the turn-on spring  23  and having a display portion corresponding to the each state, and a see through window (not shown) installed on the front plate (so called front panel) (not shown) of the circuit breaker corresponding to the display portion. It is desirable for the display plate to have a cam shape, a picture indication or a character indication indicating the extension/return of the spring corresponding to the energizing completion state or energized energy exhaustion state can be embodied. The see through window is installed on the position corresponding to the display plate on the front plate (front operation panel) exposed to the user operating the circuit breaker. 
     In addition, it is desirable to display the turn-ON state or turn-OFF state of the main circuit of the vacuum circuit breaker to the user. The display means for displaying the states comprises a display plate (not shown) coupled to the rotating shaft  9  of the switch lever  7  rotating according to the turn-ON state or turn-OFF state of the circuit breaker and having a display portion corresponding to the each state on the upper portion, and a see through window (not shown) installed on the front plate of the circuit breaker corresponding to the position corresponding to the display unit. The display plate can be embodied as a plate having a cam shape as same as the display plate of the turn-on spring  23 , and the character indication indicating the turn-on/turn-off or ON/OFF can be embodied on the front surface. The see through window is installed on the front surface (front operation panel) exposed to the user operating the circuit breaker corresponding to the position to the display plate. 
     Hereinafter, the operation and effect of the switch device according to the embodiment of the present invention will now be described with reference to accompanying FIG. 4-6. 
     First, when the power circuit of the motor  41  is connected by the first switch  77 , the power is applied, and the motor  41  rotates, accordingly the driving pole  39  rotates. 
     Herein, when the driving pole  39  rotates one time, the driving wheel  33  rotates with the one teeth interval, the reverse rotation restraining pole  43  placed centering around the driving wheel  33  to be opposite to the driving pole  39  prevents the counter lock-wise rotation of the driving wheel  39 . 
     As depicted in FIG. 4, when the driving wheel  33  rotates to the clock-wise direction, the driving arm  57  rotates to the clock-wise direction by the link  55  coupled to the turn-on cam  45 , and the turn-on spring  23  coupled to the other end of the driving arm  57  is extended according to the rotation of the driving arm  57 . 
     And, the third link  69  coupled to the opposing end to the end of the arm  59  being pulled by the returning spring  60  is upwardly lifted by the arm  59 , according to this, the first and second link  63 ,  65  coaxially coupled to the third link  69  are upwardly lifted, the switch lever  7  rotates to the counter clock-wise direction centering around the rotating shaft  9 , and the movable contactor  5  is separated from the fixed contactor  3  through the connection link  11 . Accordingly, the main circuit is cut-off. 
     As depicted in FIG. 4, according to this, the connecting pin  67  moves towards the rotating shaft  35  of the operating wheel  33 , and the second link  65  is placed on the straight line of the third link  69 . 
     Meanwhile, when the driving wheel  33  rotates as a predetermined angle, the turn-on spring  23  reaches to the maximum extended point, the roller contact portion of the turn-on cam  45  contacts to the rotation restraining roller  48 , accordingly the rotation of the turn-on cam  45  and driving wheel  33  stop. 
     Herein, the driving pole  39  performs the idling without rotating the driving wheel  33  by contacting with the gearless portion  38 . 
     Accordingly, according to the above-mentioned operation, when a detecting device (not shown, such as a rotary encoder installed on the rotating shaft of the driving wheel for generating a pulse signal corresponding to the rotation) detects the stop state of the driving wheel  33 , the first switch  77  cuts-off the power circuit to the motor  41 , and at the same time the first switch  77  switches in order to connect the power circuit to the turn-on solenoid  49 . 
     As described above, when the turn-on spring  23  is extended and the arm  59  rotates by the returning spring  60 , the turn-on latch locking bar  53  returns to the rotation permission position permitting the rotation of the turn-on latch  47 . 
     Meanwhile, in the circuit cut-off state as depicted in FIG. 4, the operation of the switching mechanism of the vacuum circuit breaker of the present invention which switches the main circuit to the turn-ON state will now be described with reference to accompanying FIG.  5 . 
     In order to connect the power to the main circuit by contacting the movable contactor  5  to the fixed contactor  3 , when the power circuit of the turn-on solenoid  49  is connected, the power is applied to the turn-on solenoid  49 . And, as depicted in FIG. 5, the rotation restraining roller  48  is separated from the turn-on cam  45  by rotating the turn-on latch  47  by the turn-on solenoid  49 . 
     According to this, as depicted in FIG. 5, the turn-on spring  23  is returned, and the arm  57  and arm  59  rotate to the counter clock-wise direction. At the same time, the wheel  33  and cam  45  rotate to the clock-wise direction. 
     Herein, the third link  69  coupled to the end of the arm  59  downwardly compresses the first and second link  63 ,  65  coupled through the connecting pin  67 , and the switch lever  7  rotates to the switch-ON position. 
     Accordingly, the cut-off spring  13  coupled to the switch lever  7  is extended and elastically energized by the rotation of the switch lever  7 , the movable contactor  5  connected to the connecting link  11  and switch lever  7  contacts with the fixed contactor  3 . Accordingly, the main circuit is in the conduction (turn-on) state. 
     Herein, the trip arm  61  rotatably coupled to the switch lever  7  rotates following the switch lever  7 , the roller  62  coupled to the extended end of the trip arm  61  rotates to the clock-wise direction while contacting with the trip latch  71 . 
     Herein, the trip latch  71  is applied the elastic force so as to rotate to the clock-wise direction by a spring (not shown), it prevents the roller  62  from reverse-rotating to the counter clock-wise direction after passing the trip latch  71 , accordingly the switch lever  7  maintains the switch-ON position. 
     When the switch lever  7  rotates to the switch-ON state, the second switch  79  connected to the switch lever  7  corresponds with the rotation of the switch lever  7 , separates the power circuit to the turn-on solenoid  49 , and at the same time connects the power circuit to the trip solenoid  75  (right side contact closed state in FIG.  5 ). 
     In the meantime, the turn-on spring  23  is returned while making the switch lever  7  rotate to the switch-ON position, the turn-on latch locking bar  53  follows the rotation of the arm  59 , and moves to the rotation restraining position so as to restrain the rotation of the turn-on latch  47 . 
     At the same time with the rotation of the switch lever  7  to the switch-ON position, the first switch  77  connected to the driving wheel  33  by a connecting member (not shown) corresponds with the rotation of the driving wheel  33 , cuts-off the power circuit to the turn-on solenoid  49 , and at the same time connects the power circuit to the motor  41 . 
     Herein, when the motor  41  rotates responding to a control from a control unit (not shown), the driving pole  38  rotates in order to rotate the wheel  33  as the one teeth interval. 
     As described above, the arm  57  rotates by the link  55  corresponding with the rotation of the wheel  33 , the spring  23  is extended by corresponding with the rotation of the arm  57 , and the spring  23  is elastically energized, accordingly the circuit breaker according to the present invention is in the state depicted in FIG.  6 . 
     Hereinafter, the switch-OFF operation of the switch device according to the present invention will now be described. 
     As depicted in FIG. 6, in the extended state (elastically energized state) of the spring  23  and spring  13 , when the over current flow due to the short circuit of the electric circuit or grounding error is detected, the control unit (not shown) applies the power to the trip solenoid  75 , and rotates the trip lever  73 . 
     According to this, the trip lever  73  pulls the latch pin  72  of the trip latch  71 , the trip latch  71  rotates to the counter clock-wise direction, accordingly the trip latch  71  separates from the end of the trip arm  61 . 
     And, the trip arm  61  and switch lever  7  rotates instaneously to the counter clock-wise direction by the elastic energy of the cut-off spring  13 , the movable contactor  5  is separated from the fixed contactor  3 . 
     Herein, the turn-on spring  23  stands by in the extended state, accordingly it can perform turn-on operation at the same time. 
     As above mentioned embodiments, the gear portion and gearless portion are formed on the circumference of the driving wheel, the driving pole and driving restraining pole are constructed in order to make the driving wheel rotate with the unit teeth interval, but it is also possible to rotate the driving wheel by forming the gear portion around the circumference of the driving wheel and forming an driving gear on the rotating shaft of the driving motor so as to be meshed with the driving wheel. 
     As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be constructed broadly within its sprit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalence of such meets and bounds are therefore intended to be embraced by the appended claims.