Patent Publication Number: US-2023160416-A1

Title: Opening/closing device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation patent application of International Application No. PCT/JP2020/031764, filed Aug. 24, 2020, the content of which is incorporated herein by reference. The PCT International Application was published in the Japanese language. 
    
    
     FIELD 
     An embodiment of the present invention relates to an opening/closing device. 
     BACKGROUND 
     In the related art, an opening/closing device is known which has a structure in which movable contacts provided for each of three phases are moved by one driving device via one shaft. For example, the shaft is constituted by a plurality of parts and provided with joints. In particular, an insulating material is used in a joint portion to prevent current from flowing. In addition, for the purpose of improving transmission efficiency and reducing the number of parts, a structure is also disclosed in which the shafts are connected as a spline to tightly transmit a torque associated with rotational movement. 
     When the opening/closing device is opened, if the shaft is rotated to move the movable contacts of each phase with a single shaft, the shaft is twisted, different delays occur between the movable contacts for each phase, and deviation in movement of the contacts may occur. Then, when the shaft is braked to stop an operation of the movable contacts for each phase, among three phases, while the movable contacts of a first phase close to an operating mechanism rapidly decelerate according to braking of the operating mechanism, the movable contacts of a second phase and a third phase far from the operating mechanism continuously move due to inertia, and the deceleration may be delayed. As a result, although the movable contacts of the first phase reach the open position and stop, the movable contacts of the second phase and the third phase exceed the open position and may bounce back. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a view showing an outline of an opening/closing device of a first embodiment. 
         FIG.  2    is a view showing an outline of an auxiliary shock absorbing mechanism. 
         FIG.  3    is a view showing a stroke curve of each movable contact that moves from a closed position to an open position. 
         FIG.  4    is a view showing a stroke curve of each movable contact when moving from a closed position to an open position in a comparing device. 
         FIG.  5    is a view showing an outline of an opening/closing device according to a second embodiment. 
         FIG.  6    is a view showing an outline of an auxiliary shock absorbing mechanism of an opening/closing device of a third embodiment. 
         FIG.  7    is a view showing an outline of an auxiliary shock absorbing mechanism of an opening/closing device of a fourth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, an opening/closing device of an embodiment will be described with reference to the accompanying drawings. An opening/closing device of an embodiment has a first movable contact, a first transmission mechanism, a first container, a second movable contact, a second transmission mechanism, a second container, a third movable contact, a third transmission mechanism, a third container, a crankshaft, an operating mechanism, and a shock absorbing mechanism. The first movable contact is accommodated in the first container. The first transmission mechanism is connected to the first movable contact. The first container accommodates at least the first movable contact. The second movable contact is accommodated in the second container. The second transmission mechanism is connected to the second movable contact. The second container accommodates at least the second movable contact and is aligned with the first container. The third movable contact is accommodated in the third container. The third transmission mechanism is connected to the third movable contact. The third container accommodates at least the third movable contact and is aligned with the second container. The crankshaft operates the first transmission mechanism, the second transmission mechanism, and the third transmission mechanism to change the first movable contact, the second movable contact, and the third movable contact from a closed state to an open state. The operating mechanism is disposed on the side of the first transmission mechanism and rotates the crankshaft. The shock absorbing mechanism is disposed on the side of the third transmission mechanism and absorbs a shock of rotational movement of the crankshaft. 
     In the application, a Z direction, an X direction, and a Y direction of an orthogonal coordinate system are defined as follows. The Z direction is a vertical direction, and a +Z direction is an upward direction. The X direction is a horizontal direction, and this is defined as a leftward/rightward direction of the opening/closing device. A +X direction is a rightward direction of the opening/closing device. The Y direction is a horizontal direction and a direction perpendicular to the X direction, and this is defined as a forward/rearward direction of the opening/closing device. A +Y direction is a forward direction. Further, terms such as “forward” and the like in this specification are expressed in terms of one direction when seen from the opening/closing device for the convenience of description. 
     First Embodiment 
     First, an opening/closing device of a first embodiment will be described.  FIG.  1    is a view showing an outline of an opening/closing device  1  of the first embodiment, and  FIG.  2    is a view showing an outline of an auxiliary shock absorbing mechanism  60 .  FIG.  1    shows the opening/closing device  1  in a plan view. The opening/closing device  1  includes, for example, a first phase  10 , a second phase  20 , a third phase  30 , a crankshaft  40 , an operating mechanism  50 , and the auxiliary shock absorbing mechanism  60 . 
     The first phase  10  includes, for example, a first container  11 , a first facing contact  12 , a first movable contact  13 , a first operating rod  14 , a first insulating operating rod  15 , a first crank lever  16 , and a first seal member  17 . An insulating medium G is sealed in the first container  11 , isolated from the external atmosphere, and hermetically sealed. The first container  11  is a hollow container elongated in the Y direction. The first facing contact  12 , the first movable contact  13 , the first operating rod  14 , the first insulating operating rod  15 , and the first crank lever  16  are received in the first container  11 . A through-hole is formed at a position in the vicinity of one end portion of the first container  11  in the longitudinal direction, and the first seal member  17  is attached to the through-hole. A first transmission mechanism  18  is constituted by the first operating rod  14 , the first insulating operating rod  15 , and the first crank lever  16 . 
     The first facing contact  12  is provided inside the first container  11  and fixed to the other end side of the first container  11  in the longitudinal direction. The first facing contact  12  protrudes toward one end (in the −Y direction) of the first container  11  in the longitudinal direction. 
     The first movable contact  13  has a concave shape that opens in the other end direction (+Y direction) of the first container  11 , and a cross section of an opening portion thereof is an O type. An opening width of a concave portion of the first movable contact  13  (an opening width in the X direction) is substantially the same as a width of the first facing contact  12  (a width in the X direction). For example, when the first movable contact  13  moves in the other end direction of the first container  11 , the first facing contact  12  and the first movable contact  13  come into contact with each other, and the first movable contact is closed. When the first movable contact  13  moves toward one end portion of the first container  11 , the first facing contact  12  and the first movable contact  13  are separated from each other, and the first movable contact  13  is opened. 
     The first movable contact  13  is provided integrally with the first operating rod  14  and connected to the first operating rod  14  in the other end portion of the first operating rod  14 . The first operating rod  14  is an elongated member in the longitudinal direction of the first container  11 . For example, the first operating rod  14  is supported on both end portions by bearings (not shown) and moves linearly in the longitudinal direction of the first container  11 . 
     The other end portion of the first insulating operating rod  15  is connected to one end portion of the first operating rod  14  through pin coupling. The first operating rod  14  is rotatable relative to the first insulating operating rod  15 . The first crank lever  16  is connected to one end portion of the first insulating operating rod  15  through pin coupling. One end portion of the first insulating operating rod  15  rotates around the pin connecting the first insulating operating rod  15  and the first crank lever  16  according to rotation of the first crank lever  16 . The first insulating operating rod  15  converts rotational movement of the first crank lever  16  into movement (linear movement) of the first operating rod  14 . 
     The first crank lever  16  is fitted and connected to the crankshaft  40 , and rotates according to rotation of the crankshaft  40 . The crankshaft  40  passes through a through-hole provided in the first container  11 . The first seal member  17  provided in the through-hole closes the through-hole through which the crankshaft  40  passes, and maintains airtightness in the first container  11 . The crankshaft  40  is supported by bearings such as ball bearings or the like (not shown) and rotates freely. 
     The second phase  20  includes, for example, a second container  21 , a second facing contact  22 , a second movable contact  23 , a second operating rod  24 , a second insulating operating rod  25 , a second crank lever  26 , and a second seal member  27 . The third phase  30  includes, for example, a third container  31 , a third facing contact  32 , a third movable contact  33 , a third operating rod  34 , a third insulating operating rod  35 , a third crank lever  36 , and a third seal member  37 . Both the second phase  20  and the third phase  30  have the same configuration as the first phase  10 . The second container  21  is aligned with the first container  11 , and the third container  31  is aligned with the second container  21 . A second transmission mechanism  28  is constituted by the second operating rod  24 , the second insulating operating rod  25 , and the second crank lever  26 , and a third transmission mechanism  38  is constituted by the third operating rod  34 , the third insulating operating rod  35 , and the third crank lever  36 . 
     The crankshaft  40  includes, for example, a first crank connecting rod  41 , a second crank connecting rod  42 , a third crank connecting rod  43 , an operating-mechanism-side coupling  44 , a first coupling  45 , a second coupling  46 , and a shock-absorbing-mechanism-side coupling  47 . The crankshaft  40  operates the first transmission mechanism  18 , the second transmission mechanism  28 , and the third transmission mechanism  38  to change the first movable contact  13 , the second movable contact  23 , and the third movable contact  33  between a closed state and an open state. The first crank connecting rod  41 , the second crank connecting rod  42 , and the third crank connecting rod  43  are provided to correspond to the first movable contact  13 , the second movable contact  23 , and the third movable contact  33 . The first crank connecting rod  41 , the second crank connecting rod  42 , and the third crank connecting rod  43  are all elongated members and have substantially the same diameter. 
     The first crank connecting rod  41  passes through the first container  11 , the second crank connecting rod  42  passes through the second container  21 , and the third crank connecting rod  43  passes through the third container  31 . The first crank lever  16  is fitted into a longitudinal central portion of the first crank connecting rod  41 , the second crank lever  26  is fitted into a longitudinal central portion of the second crank connecting rod  42 , and the third crank lever  36  is fitted into a longitudinal central portion of the third crank connecting rod  43 . 
     The operating-mechanism-side coupling  44  is attached to one end side of the first crank connecting rod  41  in a rotation axis direction. The second crank connecting rod  42  approaches the other end side of the first crank connecting rod  41 . The other end side of the first crank connecting rod  41  and the one end side of the second crank connecting rod  42  are coupled to each other by the first coupling  45 . The third crank connecting rod  43  approaches the other end side of the second crank connecting rod  42  in the rotation axis direction. The other end side of the second crank connecting rod  42  and the one end side of the third crank connecting rod  43  are coupled to each other by the second coupling  46 . The shock-absorbing-mechanism-side coupling  47  is attached to the other end side of the third crank connecting rod  43 . 
     The operating mechanism  50  is provided in the vicinity of one end side of the crankshaft  40 . The operating mechanism  50  includes, for example, a rotation shaft  51 , an operating mechanism crank lever  52 , an intermediate rod  53 , an intermediate lever  54 , a connecting link  55 , a built-in spring  56 , and a shock absorber  57 . The operating mechanism  50  is disposed on the side of the first transmission mechanism  18 , and rotates the crankshaft  40 . 
     The rotation shaft  51  is coaxial with the crankshaft  40  and coupled to one end side of the first crank connecting rod  41  via the operating-mechanism-side coupling  44 . The rotation shaft  51  is attached to the operating mechanism crank lever  52 . The operating mechanism crank lever  52  performs rotational movement around the same axis as the rotation shaft  51 . The operating mechanism crank lever  52  is coupled to the intermediate rod  53  by a pin. The intermediate rod  53  is an elongated member, and has a movable range in which it can reciprocally move in the longitudinal direction. The intermediate rod  53  rotates the operating mechanism crank lever  52  and the rotation shaft  51  using reciprocal movement in the longitudinal direction. 
     The intermediate lever  54  is connected to the intermediate rod  53 . The intermediate lever  54  has a rotation range corresponding to the movable range by the reciprocal movement of the intermediate rod  53  and around an axis parallel to the rotation shaft  51 . 
     The connecting link  55  includes two plate-shaped members. The connecting link  55  is connected to the connecting link  55  with the intermediate lever  54  sandwiched between the plate-shaped members. The connecting link  55  is connected to the intermediate lever  54  with a movable range of reciprocal movement in the upward/downward direction (Z direction) with respect to rotational movement of the intermediate lever  54 . 
     The built-in spring  56  applies a biasing force to the connecting link  55  and supplies power to the crankshaft  40  via the connecting link  55 , the intermediate lever  54 , the intermediate rod  53 , the operating mechanism crank lever  52 , and the rotation shaft  51 . When the biasing force of the built-in spring  56  is normally suppressed and an operating command of the opening/closing device  1  is output by a control device (not shown), the biasing force of the built-in spring  56  is released and applied to the connecting link  55 . The biasing force applied to the connecting link  55  is transmitted to the operating mechanism crank lever  52  via the intermediate lever  54 , and the intermediate rod  53 , the operating mechanism crank lever  52  and the rotation shaft  51  are rotated to rotate the crankshaft  40  according to rotation of the rotation shaft  51 . The biasing force applied by the built-in spring  56  is transmitted to the crankshaft  40  as power for rotating the crankshaft  40 . The built-in spring  56  is an example of a power source. 
     The shock absorber  57  starts to brake the rotating operation of the crankshaft  40  via the rotation shaft  51 , for example, when the first movable contact  13 , the second movable contact  23 , or the third movable contact  33  reaches a position where braking is started by the shock absorber  57  (hereinafter, “a braking start position”). The braking start position will be described below. 
     The auxiliary shock absorbing mechanism  60  is provided in the vicinity of the other end side of the crankshaft  40 . The auxiliary shock absorbing mechanism  60  includes, for example, a shock absorbing mechanism crank lever  61 , a damper roller  62 , and a damper  63 . The damper  63  includes a damper head  64 , a damper cylinder  65 , and a damper piston  66 . The auxiliary shock absorbing mechanism  60  is disposed on the side of the third transmission mechanism  38  and absorbs a shock of the rotational movement of the crankshaft. The auxiliary shock absorbing mechanism  60  is an example of the shock absorbing mechanism. 
     The shock absorbing mechanism crank lever  61  is coupled to the other end side of the third crank connecting rod  43  via the shock-absorbing-mechanism-side coupling  47 . A rotation axis of the shock absorbing mechanism crank lever  61  is coaxial with the crankshaft  40 , and a rotating direction of the shock absorbing mechanism crank lever  61  is the same as the rotating direction of the crankshaft  40 . 
     The damper roller  62  is attached to the other end side tip portion of the shock absorbing mechanism crank lever  61 . When the crankshaft  40  rotates, the shock absorbing mechanism crank lever  61  transmits rotation of the crankshaft  40  to the damper roller  62 . The damper roller  62  rotates and moves in a rotating direction W around the crankshaft  40  according to rotation of the crankshaft  40 . The damper roller  62  is an example of the roller member. 
     The damper  63  is disposed on a side of the third phase  30 . The damper  63  is a so-called oil damper, oil is sealed in an internal space of the damper cylinder  65  in the damper  63 , and the damper piston  66  is provided. The damper head  64  is disposed within the movable range of the shock absorbing mechanism crank lever  61 . The damper head  64  is integrated with the damper piston  66 , and reciprocal movement of the damper head  64  is transmitted as movement of the damper piston  66  therein. The damper head  64  of the damper  63  is engaged with (contacts) the damper roller  62 , and energy from rotational movement of the crankshaft  40  is absorbed by the damper cylinder  65 . The damper  63  is an example of the shock absorbing member. 
     Next, an opening operation of the opening/closing device  1  of the first embodiment will be described. The opening/closing device  1  finally separates the first movable contact  13  from the first facing contact  12  in the first container  11  by performing the opening operation. Likewise, in the second container  21  and the third container  31 , the second movable contact  23  and the third movable contact  33  are separated from the second facing contact  22  and the third facing contact  32 , respectively. 
     In the operating mechanism  50 , the connecting link  55  is operated by the biasing force of the built-in spring  56 . The connecting link  55  moves in the upward/downward direction (Z direction). The intermediate lever  54  is rotated and moved by movement of the connecting link  55 , and the intermediate rod  53  connected to the intermediate lever  54  is moved in a direction in which the operating mechanism crank lever  52  is pulled by the rotational movement of the intermediate lever  54 . The operating mechanism crank lever  52  is rotated around the crankshaft  40  by movement of the intermediate rod  53 . The rotational movement of the operating mechanism crank lever  52  is transmitted to the operating-mechanism-side coupling  44  via the rotation shaft  51 , and the first crank connecting rod  41  is also rotated similarly. 
     The first crank lever  16  is rotated by the rotational movement of the first crank connecting rod  41  to induce movement of the first insulating operating rod  15 . In the first insulating operating rod  15 , one end portion is rotated around the pin coupled to the first crank lever  16 , the other end portion is rotated around the pin coupled to the first operating rod  14 , and the first operating rod  14  is moved to be pulled to one end side of the first container  11 . 
     The first operating rod  14  is moved by movement of the first insulating operating rod  15 , and moved linearly from one end side toward the other end side of the first container  11  in the longitudinal direction of the first container  11 . The first movable contact  13  is moved linearly toward one end side of the first container  11  by movement of the first operating rod  14 . The first movable contact  13  is separated from the first facing contact  12  by movement of the first movable contact  13 . 
     The rotational movement of the first crank connecting rod  41  is transmitted to the second crank connecting rod  42  through the first coupling  45 , and the second crank connecting rod  42  is rotated. The second crank connecting rod  42  starts rotation with a delay from the first crank connecting rod  41  to an extent of a twist of the first crank connecting rod  41 , slight meshing of serrations between the first crank connecting rod  41  and the first coupling  45 , a twist of the first coupling  45 , and a twist of the second crank connecting rod  42 . The second crank lever  26 , the second insulating operating rod  25 , the second operating rod  24 , and the second movable contact  23  are moved by rotating the second crank connecting rod  42 , and the second movable contact  23  is separated from the second facing contact  22 . 
     The rotational movement of the second crank connecting rod  42  is transmitted to the third crank connecting rod  43  through the second coupling  46 , and the third crank connecting rod  43  is rotated. The third crank connecting rod  43  starts rotation with a delay from the second crank connecting rod  42  to an extent of a twist of the second crank connecting rod  42 , slight meshing of serrations between the second crank connecting rod  42  and the second coupling  46 , a twist of the second coupling  46 , and a twist of the third crank connecting rod  43 . The third crank lever  36 , the third insulating operating rod  35 , the third operating rod  34 , and the third movable contact  33  are moved by rotating the third crank connecting rod  43 , and the third movable contact  33  is separated from the third facing contact  32 . 
     The rotational movement of the third crank connecting rod  43  is transmitted to the shock absorbing mechanism crank lever  61  of the auxiliary shock absorbing mechanism  60  via the shock-absorbing-mechanism-side coupling  47  connected to the third crank connecting rod  43 . As shown in  FIG.  2   , the shock absorbing mechanism crank lever  61  rotates in the rotating direction W counterclockwise about the crankshaft  40  according to the transmitted rotational movement. When the shock absorbing mechanism crank lever  61  rotates in the rotating direction W, the damper roller  62  moves toward the damper head  64  and approaches the damper head  64 . The damper roller  62  is engaged with (contacts) the damper head  64  at the end of the operation, and moves the damper head  64  in the direction of the damper cylinder  65  to push the damper head  64  into the damper cylinder  65 . 
     The damper head  64  is integrated with the damper piston  66  provided in the damper cylinder  65 . For this reason, when the damper roller  62  pushes the damper head  64  into the damper cylinder  65 , the damper piston  66  moves in the oil in the damper cylinder  65 , and the damper  63  generates a braking force. 
     When the damper  63  generates the braking force, the third crank connecting rod  43  that rotates and moves is decelerated. Next, the second crank connecting rod  42  is delayed by the third crank connecting rod  43  and decelerated, and further, the first crank connecting rod  41  is delayed by the second crank connecting rod  42  and decelerated. Finally, the braking force of the shock absorber  57  provided in the operating mechanism  50  is applied via the connecting link  55  to brake the crankshaft  40 , and the first movable contact  13 , the second movable contact  23 , and the third movable contact  33  arrive at the open position and reach the open state. 
     Next, the results obtained by mechanism analysis of the stroke curve when the first movable contact  13 , the second movable contact  23 , and the third movable contact  33  move from the closed position to the open position will be described. In the mechanism analysis, the positions of the first movable contact  13 , the second movable contact  23 , and the third movable contact  33  (hereinafter, “movable contact position”) are defined as positions expressed as percentages with their open positions defined as 0% and their closed positions defined as 100%. 
       FIG.  3    is a view showing a stroke curve of each movable contact when moving from the closed position to the open position. A first stroke curve S 1  shows a stroke curve of the first movable contact  13 , a second stroke curve S 2  shows a stroke curve of the second movable contact  23 , and a third stroke curve S 3  shows a stroke curve of the third movable contact  33 . A command reception time t 0  is a time when an operating command output by a control device is received. 
     In addition, a braking start position is set to a movable contact position. For example, the braking start position is set to an arbitrary movable contact position of 15% or more and 25% or less, and a position of 20% for the mechanism analysis. The braking start position is determined on the basis of, for example, a stroke length of the damper piston  66  in the auxiliary shock absorbing mechanism  60  or a braking force of the shock absorber  57  and the auxiliary shock absorbing mechanism  60 . 
     In the mechanism analysis, it is assumed that the crankshaft  40  is braked by the shock absorber  57  and the auxiliary shock absorbing mechanism  60 .  FIG.  3    shows a change in time-lapse of the braking force applied to the crankshaft  40  by each of the shock absorber  57  and the auxiliary shock absorbing mechanism  60 . A first braking force curve B 1  shows a change in time-lapse of the braking force applied to the crankshaft  40  by the shock absorber  57 , and a second braking force curve B 2  shows a change in time-lapse of the braking force applied to the crankshaft  40  by the auxiliary shock absorbing mechanism  60 . 
     According to the results of the mechanism analysis, it is the first movable contact  13  that reaches the braking start position first between the first movable contact  13  and the third movable contact  33 . For this reason, in the shock absorber  57  and the auxiliary shock absorbing mechanism  60 , the shock absorber  57  disposed at a position close to the first movable contact  13  starts absorbing of a shock of rotational movement of the crankshaft  40  before the auxiliary shock absorbing mechanism  60  disposed at a position far from the first movable contact  13 . For this reason, a braking start timing (hereinafter, “a first braking start timing”) t 1  when the shock absorber  57  starts braking of the crankshaft  40  is set before a braking start timing (hereinafter, “a second braking start timing”) t 2  when the auxiliary shock absorbing mechanism  60  starts braking of the crankshaft  40 . 
     The first braking start timing t 1  may be set to a timing later than the second braking start timing t 2  or the first braking start timing t 1  may be set to the same timing as the second braking start timing t 2 . In particular, when the third movable contact  33  reaches the braking start position first between the first movable contact  13  and the third movable contact  33 , the first braking start timing t 1  is preferably set to a timing later than the second braking start timing t 2 . 
     In the mechanism analysis, a braking force of the shock absorber  57  and the auxiliary shock absorbing mechanism  60  varies as shown by the first braking force curve B 1  and the second braking force curve B 2  shown in  FIG.  3   . A braking end timing (hereinafter, “a first braking end timing”) t 3  when the shock absorber  57  terminates braking of the crankshaft  40  is set to a timing after a braking end timing (hereinafter, “a second braking end timing”) t 4  when the auxiliary shock absorbing mechanism  60  terminates braking of the crankshaft  40 . 
     The braking force added by the shock absorber  57  is greater than the braking force added by the auxiliary shock absorbing mechanism  60 , and the braking force added by the shock absorber  57  mainly causes the crankshaft  40  to brake. The first braking end timing t 3  may be set to a timing before the second braking end timing t 4  or may be set to the same timing as the first braking end timing t 3  and the second braking end timing t 4 . 
     According to the mechanism analysis, the braking force added to the crankshaft  40  by the shock absorber  57  and the auxiliary shock absorbing mechanism  60  is about 67% of the case in which a maximum value of a proportion occupied by the braking force added by the shock absorber  57  is 100%, and thus rebound can be preferably suppressed. Considering assembly changes, elastic deformation, or the like of the crankshaft  40 , the shock absorber  57 , and the auxiliary shock absorbing mechanism  60  in the opening/closing device  1 , it is preferable to set the proportion of the braking force added by the shock absorber  57  within a range of 50% to 70%. 
     Next, in the opening/closing device  1  of the first embodiment, the effect of providing the auxiliary shock absorbing mechanism  60  will be described while considering the difference from the opening/closing device (hereinafter, “a comparing device”) that is a comparison object. The comparing device is the opening/closing mechanism obtained by removing the auxiliary shock absorbing mechanism  60  from the opening/closing device  1 . 
       FIG.  4    is a view showing a stroke curve of each movable contact when moving from the closed position to the open position in the comparing device.  FIG.  4    shows a stroke curve of each movable contact in the comparing device.  FIG.  4    shows a change in time-lapse of a braking force added to the crankshaft  40  by the shock absorber  57 . A first stroke curve S 11  shows a stroke curve of the first movable contact  13 , a second stroke curve S 12  shows a stroke curve of the second movable contact  23 , and a third stroke curve S 13  shows a stroke curve of the third movable contact  33 . A braking force curve B 11  shows a change in time-lapse of a braking force added to the crankshaft  40  by the shock absorber  57 . 
     In the comparing device, when the crankshaft  40  is rotated by the operating mechanism  50 , due to the torsional rigidity generated in the crankshaft  40 , a variation occurs in the stroke between the first movable contact  13 , the second movable contact  23 , and the third movable contact  33  of the crankshaft  40 . On the other hand, in the opening/closing device  1 , when the auxiliary shock absorbing mechanism  60  is provided, it is possible to obtain a variation reduction effect in the time after the first braking start timing t 1  when the variation is especially desired to be suppressed. 
     Since the auxiliary shock absorbing mechanism  60  is not provided in the comparing device, the braking force added to the crankshaft  40 , in particular, the braking force added to the second crank connecting rod  42  and the third crank connecting rod  43  far from the shock absorber  57  may be reduced. In this case, as can be seen from the second stroke curve S 12  and the third stroke curve S 13  shown in  FIG.  4   , the second movable contact  23  and the third movable contact  33  connected to the second crank connecting rod  42  and the third crank connecting rod  43 , respectively, move beyond the open position to cause an over stroke. 
     As shown in  FIG.  4   , a large deviation between the first stroke curve S 11 , the second stroke curve S 12 , and the third stroke curve S 13  shows that a variation is increased between the first movable contact  13 , the second movable contact  23 , and the third movable contact  33  upon the opening operation. When the variation is increased between the first movable contact  13 , the second movable contact  23 , and the third movable contact  33 , they are disposed in the first container  11 , the second container  21  and the third container  31 , respectively, and interlocked to the operations of the first movable contact  13 , the second movable contact  23 , and the third movable contact  33 , respectively, and there is a pressure difference in the compression chamber (not shown) where the capacity is compressed. Accordingly, there is a pressure difference in the compression chamber. When there is a pressure difference in the compression chamber, a blast flow rate of the gas to the electrode (contact) is not stable, and cutoff performance upon the opening operation may be deteriorated. 
     On the other hand, in the opening/closing device  1 , as shown in  FIG.  3   , none of the first stroke curve S 11 , the second stroke curve S 12 , and the third stroke curve S 13  exceeds the open position. For this reason, when the auxiliary shock absorbing mechanism  60  is provided, the over stroke is suppressed in any one of the first movable contact  13 , the second movable contact  23 , and the third movable contact  33 . 
     The insulating medium G sealed in the first container  11 , the second container  21 , and the third container  31  is, for example, sulfur hexafluoride gas (SF6 gas). On the other hand, in recent years, application of alternative gas such as air, carbon dioxide gas, or the like, is considered as an alternative medium (gas) of SF6. In the opening/closing device  1 , when air or carbon dioxide gas is used as the insulating medium G, the pressure difference in the compression chamber appears greatly. This can be described via a general equation of adiabatic compression. 
     In the equation of the following (1), when an initial pressure is P0 and an initial volume is V0, the current pressure is P and the current volume is V. When the internal volume is changed from the initial pressure P0 to the current pressure P using the piston, it can be expressed by the equation (1) using a ratio of specific heat γ that takes different values depending on the gas. 
         P=P 0×( V/V 0){circumflex over ( )}γ  (1)
 
     As a physical property of a representative medium used in the insulating medium G, a ratio of specific heat γ of SF6 is 1.1, a ratio of specific heat γ of carbon dioxide is 1.3, and a ratio of specific heat γ of air is 1.4. For this reason, a difference in volume is greatly expanded by a multiplier of the ratio of specific heat γ in the carbon dioxide gas, air, or the like, and a difference in capacity of the compression chamber appears greatly in the difference in pressure. 
     In this respect, in the opening/closing device  1  of the first embodiment, the stroke curves can be aligned between the first movable contact  13 , the second movable contact  23 , and the third movable contact  33 . Accordingly, in the opening operation, the first movable contact  13 , the second movable contact  23 , and the third movable contact  33  can be stopped accurately at the open position. Further, since the difference in pressure (gas blast pressure) in the compression chamber between the first phase  10 , the second phase  20 , and the third phase  30  can be reduced, the cutoff performance can be stabilized by matching the blast flow rate of the gas to the electrode (contact). 
     Further, in the opening/closing device  1  of the first embodiment, the over stroke or rebound of the first movable contact  13 , the second movable contact  23 , and third movable contact seen in the comparing device shown by the stroke curve shown in  FIG.  4    is suppressed. For this reason, a withstanding pressure with respect to a transient recovery voltage can be maintained, and reignition can be suppressed. 
     Further, in the opening/closing device  1  of the first embodiment, the shock absorber  57  is provided on the side of the first transmission mechanism  18 , the auxiliary shock absorbing mechanism  60  is provided on the side of the third transmission mechanism  38 , and thus, torsion when the crankshaft  40  is braked is suppressed. Accordingly, mechanical yield strength of the crankshaft  40  can be increased. 
     Further, in the opening/closing device  1  of the first embodiment, the energy absorbed in the crankshaft  40  is distributed by both the shock absorber  57  and the auxiliary shock absorbing mechanism  60  included in the operating mechanism  50 . Accordingly, mechanical yield strength of the first crank connecting rod  41 , the second crank connecting rod, and the third crank connecting rod  43  in the crankshaft  40  can be improved. 
     Second Embodiment 
     Next, an opening/closing device of a second embodiment will be described. In the second embodiment and subsequent embodiments, the same components as in the first embodiment are designated by the same reference signs and description thereof will be omitted. Since an opening/closing device  2  of the second embodiment is distinguished from the opening/closing device  1  of the first embodiment in mainly a configuration of a crankshaft  70 , it will be described focusing on the differences. 
       FIG.  5    is a view showing an outline of the opening/closing device  2  of the second embodiment.  FIG.  5    shows a state in which the opening/closing device  2  is seen in a plan view. In the opening/closing device  2  of the second embodiment, the crankshaft  70  includes, for example, a first crank connecting rod  71 , a second crank connecting rod  72 , a third crank connecting rod  73 , an operating-mechanism-side coupling  74 , a first coupling  75 , a second coupling  76 , and a shock-absorbing-mechanism-side coupling  77 . 
     The crankshaft  70  operates the first transmission mechanism  18 , the second transmission mechanism  28 , and the third transmission mechanism  38  and changes the first movable contact  13 , the second movable contact  23 , and the third movable contact  33  from the closed state to the open state. The first crank connecting rod  71 , the second crank connecting rod  72 , and the third crank connecting rod  73  are provided to correspond to the first movable contact  13 , the second movable contact  23 , and the third movable contact  33 . All the first crank connecting rod  71 , the second crank connecting rod  72 , and the third crank connecting rod  73  have elongated members with a fixed size and having substantially the same length. 
     The first crank connecting rod  71  passes through the first container  11 , the second crank connecting rod  72  passes through the second container  21 , and the third crank connecting rod  73  passes through the third container  31 . The first crank lever  16  is fitted into a longitudinal central portion of the first crank connecting rod  71 , the second crank lever  26  is fitted into a longitudinal central portion of the second crank connecting rod  72 , and the third crank lever  36  is fitted into a longitudinal central portion of the third crank connecting rod  73 . 
     The operating-mechanism-side coupling  74  is attached to one end side of the first crank connecting rod  71 . The other end side of the first crank connecting rod  71  and one end side of the second crank connecting rod  72  are coupled by the first coupling  75 , and the other end side of the second crank connecting rod  72  and one end side of the third crank connecting rod  73  are coupled by the second coupling  76 . The shock-absorbing-mechanism-side coupling  77  is attached to the other end side of the third crank connecting rod  73 . 
     A geometrical moment of inertia around a rotation axis of the third crank connecting rod  73  is smaller than a geometrical moment of inertia around a rotation axis of the second crank connecting rod  72 . A geometrical moment of inertia around the rotation axis of the second crank connecting rod  72  is smaller than a geometrical moment of inertia of a rotation axis of the first crank connecting rod  71 . 
     A more specific structure of the crankshaft  70  will be described. When the first crank connecting rod  71  is provided along the rotation axis and a section modulus is calculated in the X direction, a minimum value thereof is a minimum section modulus (hereinafter, “a first minimum section modulus”) Ia of the first crank connecting rod  71 . Similarly, a minimum value when the second crank connecting rod  72  is provided along the rotation axis and a section modulus is calculated in the X direction is a minimum section modulus (hereinafter, “a second minimum section modulus”) Ib of the second crank connecting rod  72 , and a minimum value when the third crank connecting rod  73  is provided along the rotation axis and a section modulus is calculated in the X direction is a minimum section modulus (hereinafter, “a third minimum section modulus”) Ic of the third crank connecting rod  73 . 
     In the opening/closing device  2 , the first minimum section modulus Ia, the second minimum section modulus Ib, and the third minimum section modulus Ic have a relation shown in the following equation (2). The first minimum section modulus Ia, the second minimum section modulus Ib, and the third minimum section modulus Ic may have a relation shown in the following equation (3) or (4). 
         Ia&gt;Ib&gt;Ic   (2)
 
         Ia≥Ib&gt;Ic   (3)
 
         Ia&gt;Ib≥Ic   (4)
 
     A thickness (an outer diameter) of each of the operating-mechanism-side coupling  74 , the first coupling  75 , the second coupling  76  is slightly greater than the thicker one of the two connected rods, and they have different thickness between the operating-mechanism-side coupling  74 , the first coupling  75 , and the second coupling  76 . In this case, thicknesses of the operating-mechanism-side coupling  74 , the first coupling  75 , and the second coupling  76  are reduced in sequence. The operating-mechanism-side coupling  74 , the first coupling  75 , and the second coupling  76  may have the same thickness. 
     In the opening/closing device  2  of the second embodiment, the first crank lever  16  rotates with a moment of inertia on the basis of the section modulus of the first crank connecting rod  71  according to rotation of the first crank connecting rod  71 . Similarly, the second crank lever  26  rotates with a moment of inertia on the basis of the section modulus of the second crank connecting rod  72  according to rotation of the second crank connecting rod  72 , and the third crank lever  36  rotates with a moment of inertia on the basis of the section modulus of the third crank connecting rod  73  according to rotation of the third crank connecting rod  73 . 
     Here, a geometrical moment of inertia around a rotation axis of the third crank connecting rod  73  is smaller than a geometrical moment of inertia around a rotation axis of the second crank connecting rod  72 , and a geometrical moment of inertia around the rotation axis of the second crank connecting rod  72  is smaller than a geometrical moment of inertia around a rotation axis of the first crank connecting rod  71 . For this reason, a moment of inertia applied to the third crank lever  36  is smaller than a moment of inertia applied to the second crank lever  26 , and the moment of inertia applied to the second crank lever  26  is smaller than a moment of inertia applied to the first crank lever  16 . Accordingly, a delay with respect to the first crank connecting rod  41  and the second crank connecting rod  42  when the second crank connecting rod  42  and the third crank connecting rod  43  start to rotate can be reduced. Further, while a rotational torque to an extent of three phases is applied to the first crank connecting rod  41  closer to the operating mechanism  50 , since a moment of inertia applied to the third crank lever  36  connected to the third crank connecting rod  43  closer to the auxiliary shock absorbing mechanism  60  is reduced, a rotational torque applied by the third crank connecting rod  43  can be reduced. 
     Third Embodiment 
     Next, an opening/closing device of a third embodiment will be described. Since the opening/closing device of the third embodiment is distinguished from the opening/closing device  1  of the first embodiment mainly in a configuration of the auxiliary shock absorbing mechanism  60 , it will be described focusing on differences thereof. 
       FIG.  6    is a view showing an outline of the auxiliary shock absorbing mechanism  60  of the opening/closing device of the third embodiment. Like the first embodiment, the auxiliary shock absorbing mechanism  60  of the opening/closing device of the third embodiment includes the shock absorbing mechanism crank lever  61 , the damper roller  62 , and the damper  63 . The damper  63  includes the damper head  64 , the damper cylinder  65 , and the damper piston  66 . These points are common to the first embodiment. 
     The auxiliary shock absorbing mechanism  60  further includes a frame  81 , an auxiliary shock absorbing mechanism support  82 , a spacer  83 , a fixing bolt  84 , a first nut  85 , and a second nut  86 . The frame  81  is fixedly disposed above the damper cylinder  65 . The frame  81  maintains a relative positional relation to the crankshaft  40 . 
     The auxiliary shock absorbing mechanism support  82  is suspended from the frame  81 . The spacer  83  is interposed between the frame  81  and the auxiliary shock absorbing mechanism support  82 . The auxiliary shock absorbing mechanism support  82  is fixed to the frame  81  using the fixing bolt  84  with the spacer  83  sandwiched therebetween. A width between the auxiliary shock absorbing mechanism support  82  and the frame  81  can be adjusted by a thickness of the spacer  83  interposed therebetween, the number of spacers, or the like. For example, the spacer  83  is provided to adjust a relative height positional relation of the damper  63  with respect to the damper roller  62 . The spacer  83  is an example of the position adjusting mechanism. 
     A piercing hole through which the damper cylinder  65  passes is formed in a lower portion of the auxiliary shock absorbing mechanism support  82 . The first nut  85  and the second nut  86  are fixed to front and rear positions of the piercing hole, respectively. Opening portions of the first nut  85  and the second nut  86  are disposed coaxially with the piercing hole of the auxiliary shock absorbing mechanism support  82 . 
     A threaded portion  67  engaged with the first nut  85  and the second nut  86  is provided on a side surface of the damper cylinder  65 . The damper cylinder  65  passes through the piercing hole formed in the auxiliary shock absorbing mechanism support  82  and is screwed into the first nut  85  and the second nut  86 , and thus, the damper  63  is supported by and fixed to the auxiliary shock absorbing mechanism support  82 . The auxiliary shock absorbing mechanism support  82 , the first nut  85 , and the second nut  86  are an example of the support member that supports the damper  63 . 
     When the damper cylinder  65  screwed into the first nut  85  and the second nut  86  is rotated, the threaded portion  67  moves along the first nut  85  and the second nut  86 , and the damper cylinder  65  advances or retreats according to movement of the threaded portion  67 . The threaded portion  67  is provided to engage with teeth provided on the first nut  85  and the second nut  86  and adjust a relative positional relation of the damper  63  with respect to the damper roller  62 . The teeth engaged with the threaded portion  67  may be provided on the first nut  85  and the second nut  86 . For example, the teeth engaged with the threaded portion  67  may be provided in the piercing hole of the auxiliary shock absorbing mechanism support  82 . The threaded portion  67  is an example of the position adjusting mechanism. 
     In the opening/closing device of the third embodiment, as the shock absorbing mechanism crank lever  61  rotates during the opening operation, the damper roller  62  approaches the damper head  64  of the damper  63 , and eventually, the damper roller  62  comes into contact with the damper head  64 . When the damper roller  62  comes into contact with the damper head  64 , the damper piston  66  provided in the damper cylinder  65  and connected to the damper head  64  moves in the oil to achieve dissipation of the energy. The damper cylinder  65  is firmly fastened by the threaded portion  67  and the first nut  85  and the second nut  86 , and thus, the reaction force of the braking force is supported and received by the frame  81  via the auxiliary shock absorbing mechanism support  82 . 
     In the opening/closing device of the third embodiment, the auxiliary shock absorbing mechanism  60  includes the first nut  85  and the second nut  86 , and the threaded portion  67  is provided on a side surface of the damper cylinder  65 . For this reason, a position of the damper  63  with respect to the damper roller  62  can be easily adjusted by relatively rotating the damper cylinder  65  with respect to the first nut  85  and the second nut  86 . In this case, the first nut  85  and the second nut  86  may not be provided. 
     Further, in the opening/closing device of the third embodiment, the auxiliary shock absorbing mechanism  60  includes the spacer  83  interposed between the frame  81  and the auxiliary shock absorbing mechanism support  82 . A height position of the damper  63  supported by the auxiliary shock absorbing mechanism support  82  can be changed by changing the thickness or the number of the spacers  83  and adjusting the width between the frame  81  and the auxiliary shock absorbing mechanism support  82 . However, the position of the damper cylinder  65  (the damper  63 ) with respect to the damper roller  62  can be adjusted by adjusting the thickness or the like of the spacer  83 . The timing when the damper roller  62  and the damper head  64  come in contact with each other can be adjusted by adjusting the position of the damper  63  with respect to the damper roller  62 . 
     Further, adjustment of the position of the damper  63  with respect to the damper roller  62  can be executed by providing the spacers  83  with different thicknesses or adjusting the number of the spacers  83 . Accordingly, errors caused by manufacturing and assembly can be easily adjusted to generate appropriate braking position and braking force. 
     Further, the auxiliary shock absorbing mechanism support  82  through which the damper cylinder  65  passes in the damper  63  is sandwiched between the first nut  85  and the second nut  86  from the front and rear. For this reason, the damper cylinder  65  can be strongly fixed as a whole. For this reason, the position of the damper  63  supported by the auxiliary shock absorbing mechanism support  82  is stabilized, and the energy transmitted to the damper  63  via the damper roller  62  when the crankshaft  40  is braked can be reliably absorbed. 
     Fourth Embodiment 
     Next, an opening/closing device of a third embodiment will be described. Since the opening/closing device of the fourth embodiment is distinguished from the opening/closing device  1  of the first embodiment mainly in a configuration of the auxiliary shock absorbing mechanism  60 , it will be described focusing on differences thereof. 
       FIG.  7    is a view showing an outline of the auxiliary shock absorbing mechanism  60  of the opening/closing device of the fourth embodiment. Like the first embodiment, the auxiliary shock absorbing mechanism  60  of the opening/closing device of the fourth embodiment includes the shock absorbing mechanism crank lever  61 , the damper roller  62 , and the damper  63 . The damper  63  includes the damper head  64 , the damper cylinder  65 , the damper piston  66 , the frame  81 , the auxiliary shock absorbing mechanism support  82 , the spacer  83 , and the fixing bolt  84 . These points are common to the third embodiment. 
     The auxiliary shock absorbing mechanism  60  further includes a lower stud  90   a , an upper stud  90   b , a first lower nut  91   a , a second lower nut  91   b , a third lower nut  91   c , a first upper nut  91   d , a second upper nut  91   e , a third upper nut  91   f , a fixing plate  92 , a lower spacer  93 , a lower fixing bolt  94   a , and an upper fixing bolt  94   b.    
     The fixing plate  92  is disposed below the auxiliary shock absorbing mechanism support  82  and in front of the damper cylinder  65 . The fixing plate  92  is connected to the auxiliary shock absorbing mechanism support  82  via the lower stud  90   a  below the damper cylinder  65  and via the upper stud  90   b  above the damper cylinder  65 . 
     The lower stud  90   a  is fixed to be sandwiched between the first lower nut  91   a  and the second lower nut  91   b . The lower stud  90   a  is further inserted into the fixing plate  92  and fixed with the third lower nut  91   c . The upper stud  90   b  is fixed to be sandwiched between the first upper nut  91   d  and the second upper nut  91   e . The upper stud  90   b  is further inserted into the fixing plate  92  and fixed with the third upper nut  91   f . The lower stud  90   a  and the upper stud  90   b  are fixed by nuts  91   a  to  91   f , and can adjust a position of the fixing plate  92  with respect to the auxiliary shock absorbing mechanism support  82  in the Y direction and further a position of the fixing plate  92  with respect to the damper cylinder  65  in the Y direction. 
     The lower spacer  93  is interposed between the damper cylinder  65  and the fixing plate  92 . A width between the damper cylinder  65  and the fixing plate  92  can be adjusted by the thickness or the number of the interposed lower spacers  93 . For example, the lower spacer  93  is provided to adjust a positional relation of the damper  63  with respect to the damper roller  62  in a relative forward/rearward direction. The lower spacer  93  is an example of the position adjusting mechanism. 
     In the opening/closing device of the fourth embodiment, the auxiliary shock absorbing mechanism  60  includes the fixing plate  92  disposed in front of the damper cylinder  65 . When a braking force is added to the crankshaft  40 , a reaction force of the braking force is generated in the damper cylinder  65 . The generated reaction force acts on the fixing plate  92  disposed in front of the damper cylinder  65 . The fixing plate  92  is connected to the auxiliary shock absorbing mechanism support  82  by the lower stud  90   a  and the upper stud  90   b . For this reason, the reaction force generated in the damper cylinder  65  is transmitted to the auxiliary shock absorbing mechanism support  82  via the fixing plate  92 . Accordingly, the reaction force generated in the damper cylinder  65  can be reliably absorbed. 
     In the opening/closing device of the fourth embodiment, the auxiliary shock absorbing mechanism  60  includes the lower spacer  93  interposed between the damper cylinder  65  and the fixing plate  92 . It is possible to change a position of the damper  63  supported by the auxiliary shock absorbing mechanism support  82  in the forward/rearward direction by changing the thickness or the number of the lower spacers  93  or changing the width between the damper cylinder  65  and the fixing plate  92 . Accordingly, it is possible to adjust the position of the damper  63  with respect to the damper roller  62  by adjusting the thickness or the like of the lower spacers  93 . It is possible to adjust the timing when the damper roller  62  and the damper head  64  come in contact with each other by adjusting the position of the damper  63  with respect to the damper roller  62 . 
     Further, adjustment of the position of the damper  63  with respect to the damper roller  62  can be executed by providing the lower spacers  93  with different thicknesses and adjusting the number of the lower spacers  93 . Accordingly, it is possible to generate appropriate braking position and braking force by simply adjusting errors generated due to manufacture or assembly. 
     In the opening/closing device of the fourth embodiment, in order to adjust the position of the damper  63  with respect to the damper roller  62 , the lower spacer  93  is used instead of providing the threaded portions  67  in the side surfaces of the first nut  85 , the second nut  86 , and the damper cylinder  65  shown in the third embodiment. For this reason, it is possible to improve assemblability when the auxiliary shock absorbing mechanism  60  is assembled. 
     In each of the above-mentioned embodiments, in the auxiliary shock absorbing mechanism  60 , when the crankshaft  40  performs the closing operation, a return spring configured to add a biasing force to the crankshaft  40  may be provided. The return spring is provided in the auxiliary shock absorbing mechanism  60 , for example, it becomes an assist for the start of the closing operation by making the force of the return spring sufficiently strong, and thus, it is possible to reduce the variations of the first movable contact  13 , the second movable contact  23 , and the third movable contact  33  in the closing stroke. 
     In addition, in each of the above-mentioned embodiments, while the built-in spring  56  in the operating mechanism  50  functions as a power source to add power to the crankshaft  40 , a driving source or the like other than the built-in spring  56  may become a power source and power may be added to the crankshaft  40 . For example, the driving source of the operating mechanism  50  may use an electromagnetic force including a hydraulic pressure, linear driving, and motor driving. 
     In addition, in each of the above-mentioned embodiments, while the oil damper is used as the damper  63  that is a shock absorbing member, the shock absorbing member is not the oil damper, and for example, may be a gas damper, may be an electromagnetic mechanism, or may be a rotation damper or the like. In addition, each part such as an operating rod, an insulating operating rod, or the like, in the transmission mechanism is not limited to be constituted by one part, but may be constituted by a plurality of parts by appropriately integrating them. For example, the transmission mechanism may be a four-joint type instead of a three-joint type. 
     In addition, in each of the above-mentioned embodiments, the first movable contact  13 , the second movable contact  23 , and the third movable contact  33  form a concave shape, and the first facing contact  12 , the second facing contact  22 , and the third facing contact  32  form a convex type. Shapes of the movable contact and the facing contact may be a shape other than the shape described above, in which each contact can come into contact at the time of closing. For example, the movable contact may have a convex shape, the facing contact may be a concave shape, and the movable contact and the facing contact may have any one planar shape. 
     In addition, in each of the above-mentioned embodiments, while the crankshaft  40  couples the first crank connecting rod  41 , the second crank connecting rod  42 , and the third crank connecting rod  43  using the first coupling  45  and the second coupling  46 , the crankshaft may be constituted by one, two, or four rods, or more. In the case in which the crankshaft is constituted by one rod, for example, like the second embodiment, when a magnitude of a geometrical moment of inertia of the crank connecting rod corresponding to each of the first phase  10 , the second phase  20 , and the third phase  30  is changed, a stepped rod to which columnar bodies with different diameters are connected may be used. Alternatively, the crankshaft may be constituted by a rod with a tendency where a geometrical moment of inertia around a rotation axis of the crankshaft is reduced as it is located far from the operating mechanism  50 , for example, a rod with a taper where a diameter is reduced as it moves away from the operating mechanism  50 . 
     While “tending to be reduced” means, for example, that it tends to be reduced in addition to the aspect that it is uniformly reduced, in part of the middle, there is a part that it becomes larger, but it also includes an aspect that it becomes smaller as a whole. While “tending to be reduced” means, for example, an aspect in which the geometrical moment of inertia around the rotation axis of the crankshaft is gradually reduced as it is located far from the operating mechanism  50 , or a point as a protrusion where the geometrical moment of inertia is increased at a point partial distant from the operating mechanism  50  at a position separated from a position to which a part of the crankshaft, in particular, the crank lever is attached, it includes the crankshaft that is reduced as it is separated from the operating mechanism  50  as a whole. 
     In addition, in each of the above-mentioned embodiments, while the operating-mechanism-side coupling  44  configured to couple the operating mechanism  50  and the crankshaft  40  is used, the crankshaft  40  may be directly coupled to the operating mechanism  50 , for example, the rotation shaft  51  without using the operating-mechanism-side coupling  44 . Similarly, while the shock-absorbing-mechanism-side coupling  47  configured to couple the auxiliary shock absorbing mechanism  60  and the crankshaft  40  is used, the crankshaft  40  may be directly coupled to the auxiliary shock absorbing mechanism  60 , for example, the shock absorbing mechanism crank lever  61  without using the shock-absorbing-mechanism-side coupling  47 . 
     In addition, in each of the above-mentioned embodiments, while the auxiliary shock absorbing mechanism  60  is disposed on an outer side of the third transmission mechanism  38  (a right side in the X direction), it may be provided at any position as long as it is provided closer to the third transmission mechanism  38  than the operating mechanism  50 . For example, the auxiliary shock absorbing mechanism  60  may be disposed between the second transmission mechanism  28  and the third transmission mechanism  38 . In addition, the components in each embodiment may be appropriately combined. 
     According to at least one embodiment as described above, by providing a first movable contact accommodated in a first container, a first transmission mechanism connected to the first movable contact, the first container configured to accommodate at least the first movable contact, a second movable contact accommodated in a second container, a second transmission mechanism connected to the second movable contact, the second container configured to accommodate at least the second movable contact and arranged with the first container, a third movable contact accommodated in a third container, a third transmission mechanism connected to the third movable contact, the third container configured to accommodate at least the third movable contact and aligned with the second container, a crankshaft configured to operate the first transmission mechanism, the second transmission mechanism, and the third transmission mechanism and change the first movable contact, the second movable contact, and the third movable contact from a closed state to an open state, an operating mechanism disposed on the side of the first transmission mechanism and configured to rotate the crankshaft, and a shock absorbing mechanism disposed on the side of the third transmission mechanism and configured to absorb a shock of rotational movement of the crankshaft, the plurality of movable contacts can be accurately stopped at the open position in the opening operation. 
     While some embodiments of the present invention have been described, these embodiments are provided as examples and are not intended to limit the scope of the present invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and modifications may be made without departing from the spirit of the present invention. These embodiments or their modifications are included in the scope or spirit of the present invention, as well as the scope of the present invention described in the claims and their equivalents.