Grounding switch and switchgear comprising the same

Abstract

The invention relates to a grounding switch for a medium voltage switching device, the grounding switch comprising a frame supporting a mechanism for rotating a plurality of movable contacts between a first and a second reference position. The mechanism comprises a first shaft to which the movable contacts are rigidly mounted for rotation about a longitudinal axis in a closing direction of the movable contacts to the second reference position and in an opening direction of the movable contacts to the first reference position. The mechanism further comprises a second shaft coaxial with the first shaft and connectable to an operating mechanism for controlling the second shaft. The mechanism further comprises first coupling means for the shafts configured to free the second shaft from rotation relative to the first shaft at least in a first rotation phase when the second shaft is rotated according to the closing direction. The mechanism further comprises spring means operatively connected to the first coupling means, which are loaded during the first rotation phase and which release the spring energy of the spring means onto both shafts through the first coupling means when the first rotation phase has been completed.

Description

Grounding switch and switching device including the switch Technical Field

[0001] This invention relates to a grounding switch assembly for medium voltage applications. More specifically, this invention relates to a grounding switch for a medium voltage electrical switching device. Background Technology

[0002] Electrical switching devices are well known in power transmission and distribution networks.

[0003] Electrical switching devices typically comprise a metal cabinet internally divided into compartments or units to house various equipment and devices. In many applications, electrical switching devices include withdrawable switching devices (e.g., circuit breakers), meaning they are reversibly movable between a first position (inserted position) and a second position (withdrawn position), in which the switching device is electrically connected to the disconnecting contact and in the second position is electrically disconnected from the disconnecting contact.

[0004] Switching devices of the above type typically also include a grounding switch assembly. The grounding switch assembly typically includes a grounding switch, an operating mechanism for controlling the grounding switch, and a mechanical connection device, typically a connecting rod, that operably connects the grounding switch to the operating mechanism. More precisely, the general purpose of a grounding switch assembly is to ground a cable or main busbar. The grounding switch includes a mechanism for moving a plurality of movable contacts between a first reference position characterized by an open state and a second reference position characterized by a closed state. In the second reference position, the movable contacts engage fixed contacts, each of which is electrically connected to a wire.

[0005] In some known solutions, the mechanism includes a shaft on which a movable contact is rigidly mounted. The shaft rotates about a longitudinal axis, allowing the movable contact to rotate accordingly between the reference positions. Rotation in a first direction represents the closing movement of the grounding switch, while rotation in a second direction (opposite to the first direction) represents the opening movement of the grounding switch.

[0006] The rotation of the shaft is controlled by the operating mechanism mentioned above. This typically includes an actuating element that the operator can intervene on to change the state of the grounding switch. For safety reasons, the actuating element is positioned sufficiently far from the grounding switch (1000mm–2000mm) and is operably connected to the shaft of the grounding switch mechanism via a connecting device. According to a known embodiment, the actuating element is a rotating disk and is connected to the main shaft of the grounding switch mechanism via a control lever. The rotation of the disk, caused by a force acting on the lever, results in the rotation of the shaft of the grounding switch mechanism. The control lever can be moved from a first end position to a second position, the first end position and the second position corresponding to the open state and the closed state of the grounding switch, respectively. Typically, the mechanism includes a spring device operably connected to the shaft supporting the movable contact. In the first phase of the closing movement (i.e., the first rotational phase of the shaft and its mounted movable contact), the spring device is loaded. Once the rotation angle exceeds a predetermined value, the spring device releases the elastic energy on the shaft, thereby immediately and correctly bringing the movable contact into the second reference position, i.e., electrical connection with the fixed contact.

[0007] Therefore, it is possible to identify: the first stage of the closing motion, which is completed by the operator's action, i.e., the stage that is completely controlled by the operator; and the second stage that is executed after the first stage, which is executed only by the spring mechanism, i.e., the stage that is no longer under the operator's control.

[0008] In practice, the first stage depends solely on the operator's intention. This means that after grasping the lever and initiating the disengagement movement from the first position (disconnected state) to the second position (closed state), the operator can change their mind and decide to return the lever to the first position. However, in certain operating states of the switching device, this decision can be extremely dangerous.

[0009] In practice, during the first rotation phase, the moving contacts rotate in the direction of the fixed contacts, meaning they approach the fixed contacts. If one or more devices of the switching device are operating (i.e., if some components are under voltage), the initial rotation of the shaft (within the first phase) in the event of a line overvoltage is sufficient to trigger an arc between the moving and fixed contacts. Therefore, if the operator decides to stop the closing motion of the grounding switch and restore it to the open state, this could lead to arc extension with unpredictable consequences.

[0010] Therefore, a new solution is needed to prevent arcing during the closing motion of the moving contact (more precisely, during the operator-dependent phase of the motion). One possible solution is to make the closing motion completely independent of the operator. However, this solution can only be used for circuit breakers (where the operating mechanism is very close) and not for grounding switches, where the movement of the moving contact is determined by the operating mechanism installed at a location significantly away from the grounding switch. In practice, the function of the grounding switch and the arrangement of its operating mechanism necessarily require at least one phase of the closing motion to be operator-dependent. On the other hand, a grounding switch with a spring mechanism capable of performing the closing motion completely independently would require a large space and a complex design for the entire switchgear. This would result in significant costs. Summary of the Invention

[0011] The main objective of this invention is to provide a grounding switch that can overcome or mitigate the aforementioned problems of known technologies.

[0012] Against this background, the object of the present invention is to provide a grounding switch capable of accommodating an electric arc that may occur during the operator-controlled closing phase in the event of line overvoltage.

[0013] Another object of the present invention is to provide an electrical switching device that is easy to manufacture at an industrial level, has a competitive cost, and has an installation similar to that of the prior art.

[0014] According to the present invention, this objective and these and other objectives are achieved by grounding switch as described below, and these objectives and other objectives will become apparent from the following description and drawings.

[0015] Generally, the grounding switch according to the present invention includes:

[0016] - Multiple moving contacts and multiple fixed contacts;

[0017] - A frame supporting a rotational application mechanism for rotating a movable contact between a first reference position and a second reference position, wherein the movable contact is separated from the fixed contact at the first reference position and electrically connected to the fixed contact at the second reference position, wherein the rotational application mechanism includes a first shaft on which the movable contact is rigidly mounted, the first shaft rotating about a longitudinal axis in a closing direction in which the movable contact reaches the second reference position and in a disengaging direction in which the movable contact reaches the first reference position.

[0018] According to the present invention, the rotary application mechanism includes:

[0019] A second shaft, coaxial with the first shaft and connectable to an operating mechanism for controlling the second shaft, wherein the first shaft is hollow and defines a longitudinal cavity, and the second shaft is at least partially disposed within the longitudinal cavity.

[0020] - A first coupling device for the first and second shafts, the first coupling device being configured such that when the second shaft rotates from the first reference position according to the closing direction, the second shaft is freely rotatable relative to the first shaft during at least a first rotation phase; the first coupling device being configured such that the first and second shafts are rotatably connected after the first rotation phase is completed.

[0021] - A spring device operably connected to the first coupling device, wherein the spring device is loaded during the first rotation phase and, when the first rotation phase has been completed, the elastic energy of the spring device is released on the two shafts by means of the first coupling device.

[0022] Preferably, in the first reference position, the active contact is located on the first reference plane, and in the second reference position, the active contact is substantially located on the second reference plane, wherein the first reference plane and the second reference plane are orthogonal to each other.

[0023] According to one possible embodiment of the invention, the frame includes a main wall and two side walls extending from the main wall at opposite ends so as to face each other. The main wall includes an inner surface facing the rotation application mechanism. The two side walls support a first axis and a second axis at opposite ends such that the longitudinal axis is substantially parallel to the main wall.

[0024] According to a preferred embodiment, the first coupling device includes a first coupling assembly and a second coupling assembly operably arranged at opposite end portions of two shafts. The spring device includes a first spring assembly and a second spring assembly, wherein the first coupling assembly interacts with the first spring assembly, and the second coupling assembly interacts with the second spring assembly.

[0025] Preferably, at least one of the connecting components includes:

[0026] - A first cam portion, which is rigidly connected to a first shaft and includes a first slot extending through the entire longitudinal thickness of the first cam portion, the first slot extending according to a curved profile;

[0027] - A second cam portion, which is rigidly connected to the second shaft and includes a second slot that extends through the entire longitudinal thickness of the second cam portion and extends according to a curved profile; the first slot and the second slot only partially overlap with respect to the side view of the rotation application mechanism.

[0028] - A drive pin inserted longitudinally into the first slot and the second slot, wherein the drive pin is operatively connected to the spring assembly of the spring device, such that the spring assembly loads or releases its elastic energy according to the position of the drive pin.

[0029] According to one possible embodiment, the spring assembly includes a rod hinged to a pin for rotation about an axis parallel to the longitudinal axis, the rod including an abutting portion on which a first end of a spring element abuts, and the spring element including a second end abutting against a portion of the frame.

[0030] According to a preferred embodiment, the grounding switch further includes a second coupling device that operably connects a second shaft to a first shaft when the movable contact reaches a second reference position; and during rotation along the disconnection direction, the second coupling device rigidly connects the first shaft to the second shaft.

[0031] According to one possible embodiment, the second coupling device includes:

[0032] - A plurality of push plates rigidly connected to the outer surface of the second shaft, wherein each of the push plates includes a longitudinal edge;

[0033] - A plurality of openings defined through the outer surface of the first axis, each of the openings including a longitudinal edge;

[0034] When the active contact reaches the first reference position, the longitudinal edge of each push plate abuts against the corresponding longitudinal edge of the corresponding opening.

[0035] Preferably, the grounding switch includes a resilient device operably disposed between the frame and the first shaft, wherein the resilient device applies a force opposite to the closing motion, thereby preventing any oscillation / vibration of the first shaft during a first rotational phase of the second shaft along the closing direction.

[0036] Preferably, the grounding switch is provided with a damping device mounted on the frame to dampen the closing motion of the two shafts when the movable contact reaches the second reference position.

[0037] According to one possible embodiment, the damping device includes a first damping component that interacts with a first connection component of the first connection device and a second damping component that interacts with a second connection component of the first connection device, wherein each of the damping components is mounted on a frame.

[0038] Preferably, at least one of the first damping assembly and the second damping assembly includes a first damper element and a second damper element, wherein the first damper element and the second damper element provide abutment surfaces for the first cam portion and the second cam portion of the corresponding coupling assembly, respectively.

[0039] Preferably, the grounding switch includes a stop device connected to the frame to stop the disconnection movement of the two shafts when the active contact reaches a first reference position.

[0040] According to one possible embodiment, a drive pin is inserted into a rotating bushing that can rotate relative to the same drive pin sliding on the surface of the slot.

[0041] According to another possible embodiment, the pin retainer portion is mounted on the first shaft in a longitudinal position, the longitudinal position being between a first cam portion rigidly connected to the first shaft and a second cam portion rigidly connected to the second shaft, the pin retainer portion including a through hole into which a portion of the drive pin is inserted. Attached Figure Description

[0042] Other features and advantages of the invention will emerge from the description of preferred, but not exclusive, embodiments of the grounding switch according to this disclosure, non-limiting examples of which are provided in the accompanying drawings, wherein:

[0043] - Figure 1 is a view of an embodiment of a grounding switch according to the present invention in the open state;

[0044] - Figure 2 is a front view of the grounding switch in Figure 1;

[0045] - Figures 3 and 4 are two opposite side views of the grounding switch in Figure 1;

[0046] - Figure 5 is a view of the grounding switch in Figure 1 in the closed state;

[0047] - Figures 6 and 7 are two opposite side views of the grounding switch in Figure 5;

[0048] - Figure 8 is a top view of the grounding switch in Figure 5;

[0049] - Figures 9 and 10 are front views of the components of the grounding switch in Figure 8;

[0050] - Figure 11 is an exploded view of the grounding device in Figure 8;

[0051] - Figure 12 shows the details of the grounding switch in Figure 8;

[0052] - Figure 13 is a detailed cross-sectional view of Figure 12;

[0053] - Figure 14 is a perspective view of some components of the grounding switch in Figure 8;

[0054] - Figures 15 and 16 show the first group of components and the second group of components shown in Figure 14, respectively;

[0055] - Figure 17 is a cross-sectional view of the grounding switch mechanism of Figure 1 obtained from section line C-B of Figure 8;

[0056] Figures 18 and 19 are cross-sectional views of the grounding switch mechanism of Figure 1 obtained from section line C-A of Figure 8. Each of Figures 18 and 19 refers to the instantaneous closing motion of the grounding switch from the open state to the closed state.

[0057] Figures 20-21 are perspective views of the grounding switch mechanism in Figure 1, each showing the instantaneous closing motion of the grounding switch from the open to the closed state.

[0058] Figures 22-26 are views of the mechanism of the grounding switch in Figure 1, with each figure representing a different moment in the disconnection movement of the grounding switch from the closed state to the open state. Detailed Implementation

[0059] Referring to the above figures, the present invention relates to a grounding switch 1 for medium voltage applications. For the purposes of this invention, the term "low voltage" (LV) refers to an operating voltage below 1 kV AC, while the term "medium voltage" (MV) refers to an operating voltage above 1 kV up to tens of kV (e.g., 52 kV) AC.

[0060] The grounding switch 1 includes a frame 5 that supports a mechanism 4 configured to move a plurality of movable contacts 2 relative to a fixed contact 3 (shown schematically only in Figures 6 and 7). More precisely, the mechanism 4 is configured to rotate the movable contacts 2 between a first reference position and a second reference position, in which the movable contacts 2 are separated from and away from the fixed contact 3, and in the second reference position, the movable contacts 2 are electrically connected to the fixed contact 3. Thus, the first reference position and the second reference position represent the open and closed states of the grounding switch 1, respectively.

[0061] Figures 1-4 illustrate one possible embodiment of the grounding switch 1 in the open state, while Figures 5-8 illustrate the same grounding switch 1 in the closed state. According to the invention, mechanism 4 includes a first shaft 11 (also referred to as "conductive shaft 11") that rotates about a longitudinal axis 101. A movable contact 2 is rigidly mounted on the first shaft 11 to rotate between a first reference position and a second reference position. More precisely, according to the closing movement of the grounding switch 1, the first shaft 11 rotates along a first direction W1 (or the closing direction W1) such that the movable contact 2 rotates from the first reference position to the second reference position (see Figure 1). According to the opening movement of the grounding switch 1, the first shaft 11 can rotate along a second direction W2 (or the opening direction W2) such that the movable contact 2 rotates from the second reference position to the first reference position (see Figure 5).

[0062] According to the invention, mechanism 4 further includes a second shaft 12 (also referred to as "conductor shaft 12") coaxial with the first shaft 11 (i.e., rotating about the axis 101). As better explained below, the second shaft 12 can be connected to an operating mechanism (not shown) controlled by an operator.

[0063] The first shaft 11 is preferably hollow along its entire longitudinal length. The second shaft 12 is at least partially arranged in the longitudinal cavity of the first shaft 11. In particular, a bearing assembly (not shown) supports the second shaft 12 in the longitudinal cavity, thereby allowing the second shaft 12 to rotate relative to the first shaft 11.

[0064] Mechanism 4 includes first connecting devices 15A and 15B between two shafts 11 and 12. The connecting devices are configured such that the second shaft 12 can rotate freely relative to the first shaft 11 for a first rotational phase (i.e., a predetermined rotational angle) when its rotational direction corresponds to the closed direction W1. After this first rotational phase, the connecting devices rotatably engage the two shafts 11 and 12 (rigidly rotated), allowing them to rotate synchronously about a common axis 101. Therefore, due to the connecting devices, the two shafts 11 and 12 rotate together only after the second shaft 12 has completed a predetermined rotational angle, denoted by α1 in FIG. 18. This angle α1 defines the first rotational phase during which the first shaft 11 does not rotate, i.e., during this first rotational phase, the movable contact 2 remains in a first reference position (the open state of switch 1).

[0065] According to the invention, mechanism 4 further includes spring devices 13A and 13B, which are loaded by the second shaft 12 during a first rotational phase and release their load (i.e., release their elastic energy) after the first rotational phase is completed (i.e., when the two shafts 11 and 12 are rotatably engaged by means of the first coupling device 15A and 15B). When the spring devices 13A and 13B release their elastic energy, the movable contact 2 rotates together with the first shaft 11 to reach a second reference position, i.e., to close switch 1.

[0066] According to a preferred embodiment, in the first reference position (switch 1 open), the movable contact 2 is substantially located on the first reference plane PV, for example, on a vertical plane. In the second reference position (switch 1 closed), the movable contact 2 is substantially located on a second reference plane PH (e.g., a horizontal plane) orthogonal to the first reference plane PV. Therefore, during the closing movement and after the elastic energy of the spring devices 15A and 15B is released, the movable contact 2 is rotated by 90 degrees.

[0067] According to one possible embodiment, frame 5 includes a main wall 51 and two side walls 52, 53, which extend from the main wall 51 at opposite ends to face each other. The main wall 51 includes an inner surface 51A facing the mechanism 4. The two side walls 52, 53 support shafts 11, 12 at opposite ends. Preferably, the two side walls 52, 53 extend from the inner surface 51A of the main wall 51 orthogonally (see, for example, Figures 1 and 8). The longitudinal axes 101 of the two shafts 11, 12 are substantially orthogonal to the side walls 52, 53 and parallel to the main wall 51. Frame 5 also includes a bottom wall 54 having an inner surface 54A (facing the mechanism 4) for loading a spring device, as better described below.

[0068] According to one possible embodiment, the movable contacts 2 project radially from the main shaft 12 in a radial plane including the longitudinal axis 101. When the movable contacts 2 are in the first reference position, they are contained within a volume defined by the main wall 51 and the side walls 52, 53, as also clearly shown in Figures 2 and 3.

[0069] According to a known solution, for each movable contact 2, a central support element 2A is provided and two copper plates 2B are arranged on opposite sides of the support element 2A. For each movable contact 2, at least one movable contact on the copper plate 2B is electrically connected to the corresponding plate of the adjacent contact via a connecting copper plate 2C (see Figure 2). One or more of these copper plates 2B, 2C are electrically connected to the cable 2D for grounding.

[0070] The connecting device includes a first connecting assembly 15A and a second connecting assembly 15B operably arranged at the opposite end portions of the two shafts 11, 12. Similarly, the spring device also includes a first spring assembly 13A and a second spring assembly 13B located at the opposite end portions of the two shafts 11, 12. For example, as clearly shown in Figures 1 and 5, the first connecting assembly 15A interacts with the first spring assembly 13A, and both are arranged close to the first sidewall 53 of the frame 5. Similarly, the second connecting assembly 15B interacts with the second spring assembly 13B, and both are arranged close to the second sidewall 52. The following description primarily relates to the first connecting assembly 15A and the first spring assembly 13A. However, the technical solutions, operating principles, and / or related considerations, with necessary modifications in detail, also apply to the second connecting assembly 15B and the second spring assembly 13B.

[0071] According to a preferred embodiment, a control lever 16 is mounted on a first end 12A of the second shaft 12. Such a control lever 16 can be connected, for example, to an operating mechanism (not shown) that can be controlled by an operator via a connecting rod (not shown). The control lever 16 is located near the outer surface 53A of the side wall 53 of the frame 5 (see Figures 3 and 6), from which the first end 12A protrudes. Rotation of the control lever 16 in one of the possible directions W1 or W2 (clockwise or counterclockwise) causes the second shaft 12 to rotate accordingly in the same direction. Clearly, the direction of rotation of the first shaft 11 depends on the state of the mechanism 4, i.e., on the position of the movable contact 2.

[0072] Referring to Figures 8 through 16, according to one possible embodiment, the first coupling assembly 15A includes at least a first cam portion 151 rigidly connected to a first shaft 11 (see Figure 10) for rotation about a longitudinal axis 101. The first cam portion 151 includes a first slot 151B extending along its entire thickness, wherein the thickness is considered along the longitudinal direction (i.e., parallel to the longitudinal axis 101). The first slot 151B extends according to a curved profile.

[0073] The first coupling assembly 15A also includes a second cam portion 152 (see FIG. 9) rigidly connected to the second shaft 12. Therefore, the second cam portion 152 and the second shaft 12 always rotate together about the longitudinal axis 101. According to one possible embodiment shown in the figure, the second cam portion 152 includes a first plate 153A and a second plate 153B, both projecting from the second shaft 12. The two plates 153A, 153B are axially spaced apart by a reinforcing element 154. Alternatively, the second cam portion 152 may be defined by a single body connected to the second shaft 12.

[0074] In any case, the second cam portion 152 includes a second slot 152B that extends through the entire longitudinal thickness of the second cam portion 152 (i.e., extends parallel to the longitudinal axis 101). In the embodiment shown in the figures, each of the plates 153A, 153B has a slot facing the other plate 153B, 153A and corresponding (in shape and size) to the slot of the other plate 153B, 153A. Thus, in the case shown in the figures, the second slot 152B is actually defined by two spaced-apart slots, each slot being one of the corresponding plates 153B, 153A. Alternatively, the second cam portion 152 may be defined as a single plate longitudinally intersecting the single second slot 152B.

[0075] Like the first slot 151B above, the second slot 152B also extends according to a curved profile. The profile of the second slot 152B only partially overlaps with the profile of the first slot 151B in a side view, which is the viewpoint indicated by arrow T in FIG8. Each of the slots 151B and 152B includes inner ends 112, 142 and outer ends 111, 141, respectively, which are close to and away from the main wall 51 of the frame 5, respectively, considering the grounding switch in the off state.

[0076] The first connecting assembly 15A also includes a drive pin 85, which is longitudinally inserted into both the first slot 151B and the second slot 152B. Therefore, movement of the second cam portion 152 can be transmitted to the first cam portion 151 via the pin 85. Simultaneously, movement of the pin 85, determined by an external force acting on it, can also be transmitted to both cam portions 151 and 152. Thus, on one hand, the position of the connecting pin 85 depends on the angular position of the two cam portions 151 and 152. On the other hand, the external force applied to the pin 85 can determine the rotation of the cam portions 151 and 152, and thus the rotation of the shafts 11 and 12.

[0077] From a side viewpoint, pin 85 is always oriented in a direction substantially parallel to the longitudinal axis 101. This is because slots 151B and 152B are equidistant from the longitudinal axis X and partially overlap with respect to the side viewpoint (T).

[0078] The first spring assembly 13A is operatively connected to the pin 85, such that the first spring assembly is loaded or unloaded depending on the position of the pin 85. More precisely, when the second shaft 12 rotates in the closed direction W1, during a first rotational phase, the first spring assembly 13A is compressed (i.e., loaded) between the connecting pin 85 and the frame 5. During this first rotational phase, the pin 85 is pushed by the second cam portion 152, which rotates integrally with the second shaft 12. Simultaneously, the pin 85 moves relative to the second slot 152B, i.e., relative to the first cam portion 151. The first cam portion 151 does not move because it is integral with the first shaft 11.

[0079] As described above, the first rotation phase ends after the first cam portion 151 has rotated by a predetermined rotation angle α1. In this case, the spring assembly 13A reaches its maximum load / compression. Once the rotation angle α1 is exceeded, the spring assembly 13A releases its elastic energy onto the pin 85, which transmits this elastic energy to the two cam portions 151, 152 of the first coupling assembly 15A via corresponding slots 151B, 152B. This causes both shafts 11, 12 to rotate in the closed direction W1.

[0080] According to a possible embodiment clearly shown in the figures, the first spring assembly 13A includes a rod 131 hinged to a pin 85 (see, for example, Figures 14 to 16). Specifically, the first spring assembly 13A is freely rotatable about an axis parallel to the longitudinal axis 101 relative to the axis of the pin 85. The rod 131 includes an abutment portion 131A, on which a first end 133A of a spring element 133 abuts. The spring element 133 extends about the rod 131 and includes a second end 133B abutting against a portion of the frame 5. Preferably, as shown, the second end 133B abuts against an inner portion 54A of the bottom wall 54 of the frame 5. Thus, the spring element 133 is included between the bottom wall 54 and the abutment portion 131A of the rod 131.

[0081] In the embodiment shown in the accompanying drawings (especially Figures 1 to 7), the rod 131 intersects the bottom wall 54 such that at least a portion 131B protrudes below the bottom wall 54. The rod 131 is continuously pushed upward by the spring element 133. Hinged to the pin 85, the rod 131 is free to rotate relative to the frame 5, and this rotation (depending on the position of the pin 85) causes the spring element 133 to compress or release.

[0082] According to one embodiment shown in the figures, rod 131 is hinged to pin 85 at (or near) its upper end 131C. Preferably, the first spring assembly 13A is arranged such that the upper end 131C is located between two plates 153A, 153B defining the second cam portion 152. Thus, the upper end 131C is connected to a first longitudinal section 85A of pin 85, which is longitudinally included between the two plates 153A, 153B (see Figures 12 and 13). This means that the first longitudinal section 85A intersects the second cam portion 152. The second longitudinal section 85B of pin 85 is longitudinally included between the first cam portion 151 and the second cam portion 152, while the third section 85C intersects the first cam portion 151 (see Figure 13).

[0083] According to one embodiment of the invention, the grounding switch 1 further includes second connecting devices 16A and 16B, which operably connect the second shaft 12 to the first shaft 11 when the closing motion is completed (i.e., when the movable contact 2 reaches the second reference position). More precisely, the second connecting devices 16A and 16B rigidly connect the first shaft 11 to the second shaft 12 during the opening motion, such that the two shafts 11 and 12 rotate synchronously about the longitudinal axis 101 at least during the first rotation phase.

[0084] According to a preferred embodiment shown in the figures, the second coupling device includes a plurality of push plates 161A, 161B, which are rigidly connected to the outer surface of the second shaft 12, for example, by screws. The second coupling devices 16A, 16B include a plurality of openings 161, 162 (see Figure 10) defined through the outer surface of the first shaft 11. Each of the push plates 161A, 161B is arranged in a corresponding opening 161, 162 and includes longitudinal edges 165A, 165B parallel to the longitudinal axis 101 (see Figure 8). In the second reference position of the movable contact 2, each of the longitudinal edges 165A, 165B abuts against a corresponding longitudinal edge 166A, 166B of the corresponding opening 161, 162 (see Figure 10). Starting from the state shown in Figure 5 (grounding switch 1 closed), when the second shaft 12 rotates in the disconnection direction W2 via the control lever 16, each of the push plates 161A and 161B pushes the first shaft 11 at the longitudinal edges 166A and 166B of the corresponding openings 161 and 162 to rotate it. This causes the two coaxial shafts 11 and 12 to rotate synchronously.

[0085] According to one embodiment of the invention, the grounding switch 1 further includes an elastic device 60 operably connected between the frame 5 and the first shaft 12. The elastic device 60 applies a constant force opposite to the closing movement (i.e., rotation of the first shaft 11 along the closing direction W1). The function of the elastic device 60 is to prevent any rotation of the first shaft 11 along the closing direction W1 of the second shaft 12 during the first rotation phase. Indeed, due to use, the bearings supporting and allowing the two shafts 11, 12 to rotate relative to each other may experience friction. As a result, during the first rotation phase, the first shaft 11 will oscillate / vibrate about the longitudinal axis 101. This will cause a corresponding oscillation / vibration of the movable contact 2. By applying a force that tends to rotate the first shaft 11 along the disconnecting direction W2, the elastic device 60 keeps the first shaft 11 stopped, thereby preventing any vibration from occurring during the compression of the spring assemblies 13A, 13B. This solution allows for further increases in the safety of the grounding switch 1.

[0086] According to a preferred embodiment shown in the figure, the elastic device 60 includes a spring 66 having a first end 60A connected to the first shaft 11 and a second end 60B connected to the main wall 51 of the frame 5, such that the spring applies a force that tends to rotate the first shaft 11 in the opening direction W2 (i.e., tends to hold the movable contact 2 in the first reference position).

[0087] According to one embodiment, the grounding switch 1 is provided with damping devices 17A, 17B mounted on the frame 5 to dampen the closing movement of the two shafts 11, 12 when the movable contact 2 reaches the second reference position.

[0088] According to one embodiment shown in the figure, the damping devices 17A, 17B include a first damping component 17A that interacts with a first connecting component 13A and a second damping component 17B that interacts with a second connecting component 13B. Each of the damping components 17A, 17B is mounted on the frame 5, preferably on the inner surface 51A of the main wall 51, so as to contact the first cam portion 151 and the second cam portion 152 of the corresponding connecting component 13A, 13B when the movable contact 2 reaches the second reference position.

[0089] Referring specifically to Figure 2, the first damping assembly 17A includes a first damper element 121 and a second damper element 122, which provide abutment surfaces for the first cam portion 151 and the second cam portion 152 of the first coupling assembly 15A, respectively. Preferably, the damper elements 121 and 122 include springs and / or elastomers. According to a preferred embodiment, the first damper element 121 includes a spring disposed between the frame 5 and an enlarged head of the first pin, a section of the first cam portion 151 abutting against the enlarged head. Alternatively, the second damper element 122 includes an elastomer disposed between the frame and an enlarged head of the second pin, the enlarged head of the second pin defining an abutment surface for a section of the second cam portion 152.

[0090] In this regard, the perspective view of Figure 5 shows how the cam portions 151, 152 abut against the corresponding damper elements 121, 122 when the grounding switch 1 is in the closed state. As can be clearly seen from Figure 5, the above considerations and solutions for the first damping assembly 17A are also effective for the second damping assembly 17B.

[0091] As shown in Figures 10 and 11, for each connecting assembly 15A, 15B, the profile of the first cam portion 151 includes a first abutment section 178A that contacts the first damper element 121 at the end of the closing motion. Similarly, the second cam portion 152 (specifically each of plates 153A, 153B) includes a corresponding abutment section 178B that contacts the second damper element 122 at the end of the closing motion. The abutment sections 178A, 178B are generally straight. The cam portions 151, 152 are shaped such that the corresponding first abutment sections 178A, 178B are substantially parallel to the second reference plane PH when switch 1 is open, and substantially parallel to the first reference plane PV when switch 1 is closed.

[0092] Preferably, the grounding switch 1 further includes a stop device connected to the frame 5 to stop the closing movement of the two shafts 11, 12 when the movable contact 2 reaches the second reference position. The stop devices 18A, 18B interact directly or indirectly with the two shafts 11, 12 to prevent them from rotating, except at a predetermined angle relative to the arrangement of the movable contact 2 on the first reference plane PV.

[0093] According to a preferred embodiment illustrated in Figures 17 and 18, the stop devices 18A, 18B include a plurality of openings 181, 182 defined through the main wall 51 of the frame 5. Each of these openings 181, 182 is vertically defined by edges 181B, 182B parallel to the longitudinal axis 101. Each edge 181B, 182B serves as a stop for a reference element rigidly connected to a corresponding shaft 11, 12.

[0094] According to the embodiment (see Figures 9 and 10), the reference element of the first shaft 11 is defined by the second abutment section 179A of the first cam portion 151, while the second and third reference elements of the second shaft 12 are defined by the second abutment section 179B of one of the two plates 153A and 153B, respectively.

[0095] Referring to Figure 17, when switch 1 is open, the second abutment section 179A of the first cam portion 151 and the second abutment section 179B of the second cam portion 152 remain abutting against the edge 181B of the first opening 181 and the edge 182B of the second opening 182, respectively (only components 182B-182-179B are shown in the cross-sectional view of Figure 17). Referring to Figure 18, during the first rotation phase of the second shaft 11 (before the movable contact 2 moves to the second reference position), the second abutment section 179A of the first cam portion 151 maintains its position abutting against the edge 181B of the first opening 181.

[0096] According to one embodiment shown in the accompanying drawings, the aforementioned defined pin 85 is preferably inserted into a rotating bushing rotatable relative to the same pin 85. This bushing is essentially a housing (not shown) of the pin 85 that slides on the surfaces of the first slot 151B and the second slot 152B. This solution advantageously improves the durability and reliability of the grounding switch 1.

[0097] Preferably, for each coupling assembly 15A, 15B, the pin retainer portion 90 is mounted on the first shaft 11 in a longitudinal position, which includes a first cam portion 151 rigidly connected to the first shaft 11 and a second cam portion 152 rigidly connected to the second shaft 12. As clearly shown in the exploded view of FIG11, the pin retainer portion 90 includes a through-hole into which the second segment 85B of the pin 85 is inserted. The pin retainer portion 90 is freely rotatable relative to the second shaft 12 on which it is mounted. Its function is to support the pin 85 and increase the rotational stiffness of the second segment 85B of the pin itself. More precisely, the pin retainer portion 90 is also freely rotatable relative to the first shaft 11. Because the pin retainer portion 90 rotates integrally with the pin 85, the pin retainer portion 90 reduces the deflection and deformation that may occur during the coupling of the two shafts 11 due to the release of elastic energy. Advantageously, the pin retainer portion 90 reduces the bending moment on the second section 85B of the pin 85, allowing the pin to operate under shear.

[0098] Referring particularly to Figures 5 and 12, according to one possible embodiment, the second cam portion 152 includes a disconnecting roller 185 arranged between two plates 153A, 153B. This roller 185 rotates freely about an axis substantially parallel to the longitudinal axis 101. During the second phase of the disconnecting motion, i.e., as soon as the spring element 133 reaches its dead point, the disconnecting roller 185 pushes the rod 131 of assembly 13A and thus the pin 85. In effect, the disconnecting roller 185 is part of the second cam portion 152 that pushes the rod 131 from the neutral position (the dead point of spring assemblies 13A, 13B) to the position of the grounding switch 1 characterized by the disconnected state (see Figures 25 and 26 explained below). Specifically, the action of the disconnecting roller 185 causes rotational movement of the rod 131 of spring assemblies 13A, 13B.

[0099] Figures 17 to 21 are side views of mechanism 4 of the grounding switch 1, each view characterized at a moment of closing movement. In these figures, the frame 5 has been removed for clarity. Figure 17 shows mechanism 4 in the open state when the moving contact 2 is separated from the fixed contact 3 (first reference position). For convenience, in the following description, reference will be made only to the first connecting assembly 15A and the first spring assembly 13A. However, these considerations also apply to the second connecting assembly 15B and the second spring assembly 13B.

[0100] In the state shown in Figure 17, the pin 85 of the first connecting assembly 15A contacts the inner end 142 of the second slot 152B, and the rod 131 is oriented toward the main wall 51 (as illustrated in the schematic diagram). More specifically, the rod 131 is inclined at an angle β1 relative to the first reference plane PV on which the movable contact 2 is placed. The spring element 133 holds the reference elements (segments 179A, 179B) of the cam portions 151, 152 against the stop (edges 181B, 182B of the openings 181, 182) associated with the main wall 51 of the frame 5. At the same time, the disconnecting roller 185 of the second cam portion 152 also abuts against the side of the rod 131 opposite to the side facing the main wall 51.

[0101] As described above, the closing of switch 1 is actuated by an operator who controls a control lever 16 (not shown in Figures 17-19) integrated with the second shaft 12 via an operating mechanism (not shown). As can be seen from the configuration shown in Figure 17, the control lever 16 rotates in the closing direction W1. This rotation causes the second shaft 12 to rotate in the same direction, while the first shaft 11 remains independent of the second shaft 12 during this phase. In this respect, the elastic device 60 prevents the first shaft 11 from oscillating during the first rotation phase of the second shaft 12.

[0102] Referring to Figure 18, the second shaft 12 rotates by a first angle α1 until the spring assembly 13A reaches its dead point, i.e., the aforementioned neutral position, in which the axis of the rod 131 is aligned with the first reference plane PV (β1=0). During this first rotation phase, the first cam portion 151 of the first shaft 11 remains in position abutting against the stop device 18A (the second abutting section 179A abuts against the edge 181B of the first opening 181). This is because the pin 85 of the first connecting assembly 13A moves relative to the first slot 151B of the first cam portion 151. Simultaneously, the rod 131 of the spring assembly 13A rotates in the opposite direction W2, causing the spring element 133 to be compressed between the inner surface 54A of the bottom wall 54 of the frame 5 and the abutting portion 131A of the rod 131. In fact, the rotation angle α1 corresponds to the loading phase of the spring element 133.

[0103] In the state shown in Figure 18, the pin 85 of the connecting assembly 13A is always in contact with the inner end 142 of the second slot 152B of the second cam portion 152. However, in this state, a gap (defined by the second angle α2) exists between the axis of the pin 85 and the outer end 111 of the first slot 151B of the first cam portion 151. This gap allows for proper loading of the spring element 133 and stopping of the movable contact 2 when the spring assembly 13 is at its dead point. This state ensures that the spring element 133 releases its elastic energy after passing the dead point. In fact, only in this state does the pin 85 contact the outer end 111 of the first slot 151, making the closing movement of the movable contact 2 completely independent of the operator.

[0104] Once the dead point is reached, the spring element 133 releases its load. This triggers the movement of the pin 85 relative to the two slots 151B and 152B. The pin 85 contacts the outer end 111 of the first slot 151B and determines the rotation of the first shaft 11, that is, the rotation of its movable contact 2. Similarly, the second shaft 12 rotates by the action of the pin 85 on the outer end 141 of the second slot 152B.

[0105] Figure 19 illustrates the mechanism in which the first shaft 11 rotates due to the instantaneous contact between the pin 85 and the outer end 111 of the first slot 151B when the pin 85 is moved by the spring element 133. This contact occurs after the rotation of the pin 85 equals the aforementioned second angle α2.

[0106] In summary, the sum of the first angle α1 and the second angle α2 defines the rotation angle of the second shaft 12, which is independent of the rotation of the first shaft 11. As described above, the first angle α1 is characterized by a first rotation phase controlled by the first operator, i.e., a phase dependent on the operator's intention. If the operator decides to stop the closing operation in this phase, the spring element 133 will force the second shaft 12 to return to the state shown in FIG. 17 (moving the contact 2 to the first reference position). In any case, in this phase, the first shaft 11 and the moving contact 2 do not rotate.

[0107] Angle α2 is characterized by a rotational phase in which the second axis 11 of the closed motion is no longer controlled by the operator. However, during this further phase, the first axis 11 does not move relative to the second axis 12.

[0108] Figure 20 shows the mechanism in which the two shafts 11 and 12 rotate together in the first direction W1 until the movable contact 2 reaches the second reference position (i.e., until the switch 1 is closed (see Figure 21)). The configuration shown in Figure 20 follows that in Figure 19. Pin 85 contacts and thus pushes the outer ends 111 and 141 of the two slots 151B and 152B of the first coupling assembly 15A.

[0109] Referring to Figure 21, when the mechanism reaches the closed configuration (switch 1 closed), the movable contact 2 is located on the second reference plane PH. The slots 151B and 152B of the cam portions 151 and 152 are aligned as shown in the position where the pin 85 still contacts the outer ends 111 and 141 of each of the slots 151B and 152B. The rod 131 of the spring assembly 13A is tilted at an angle β2 relative to the first reference plane PV, while the first cam portion 151 and the second cam portion 152 are rotated 90° relative to the configuration shown in Figure 17 (switch open state).

[0110] Referring always to FIG21, during the closing motion until the dead point of the first spring assembly 13A (i.e., during the first rotation phase), the elastic device 60 is actually opposed to the closing action exerted by the spring element 133. However, the spring element 133 is designed such that its action on the pin 85 and shafts 11, 12 is unaffected by the elastic device 60. When the spring assembly 13A passes the dead point (more precisely, when the pin 85 contacts the outer end 111 of the first slot 151B), the elastic device 60 is no longer opposed to the closing motion. Instead, the elastic devices 60 release their elastic energy cooperating with the spring element 133 to rotate the first shaft 11 and the movable contact 2 until the grounding switch 1 is closed.

[0111] Figure 21 also shows how the cam portions 151, 152 are stopped by the corresponding damper elements 121, 122 (schematically illustrated by dashed square elements).

[0112] Figures 22-26 relate to the disconnection movement of switch 1, which is achieved by rotation of the two shafts 11, 12 in a second direction W2 (counterclockwise in the figures). As described above, this disconnection movement is achieved by second connecting devices 16A, 16B, which rotatably connect the two shafts 11, 12. Specifically, in the state shown in Figure 22, for each push plate 161A, 161B connected to the second shaft 12, the longitudinal edges 165A, 165B abut against the longitudinal edges 166A, 166B of the corresponding openings 161, 162 of the first shaft 11. Therefore, when the disconnection movement begins (after the action applied to the control lever 16 (not shown in Figure 21), the two shafts 11, 12 rotate synchronously opposite to the spring elements 133 of the two spring assemblies 13A, 13B. Therefore, the operator must apply sufficient torque via the control lever 16 to load / compress the spring elements 133 of the spring assemblies 13A and 13B, as well as to load / compress the aforementioned spring device 60.

[0113] In this regard, Figures 23 and 24 are perspective and side views of mechanism 4 at two different moments during the first rotational phase of the disengagement motion, respectively, where the two axes 11 and 12 rotate synchronously. During this phase, for each connecting assembly 15A and 15B, pin 85 is pushed by two corresponding cam portions 151 and 152, particularly at the outer ends 111 and 141 of slots 151B and 152B. As described above, during this first rotational phase, the spring elements 133 of spring assemblies 13A and 13B are loaded / compressed, and rod 131 rotates toward the main wall 51 of frame 5.

[0114] Referring to Figure 24, after rotating by a first angle δ1 along the second direction W2, the disconnecting roller 185 begins to push the rod 131. As soon as the spring assembly 13A approaches its end point, the pin 85 moves relative to the outer ends 111, 141 of the slots 151B, 152B specifically pushed by the disconnecting roller 185.

[0115] Figure 25 shows mechanism 4 when spring assemblies 13A and 13B reach their dead points after a further rotation by a second angle δ2 along the disconnecting direction W2 relative to the state of Figure 24. For both spring assemblies 13A and 13B, lever 131 is still pushed by disconnecting roller 185. Overall, the two angles δ1 and δ2 define the first rotational phase controlled by the operator acting on control lever 16.

[0116] Once the state shown in Figure 25 has been reached, the spring assemblies 13A and 13B release their elastic energy onto the pin 85. For each connecting assembly 15A and 15B, this causes a pushing action on the two cam portions 151 and 152, and thus causes rotation of the shafts 11 and 12 to achieve the state shown in Figure 26 (corresponding to the state in Figure 17), in which the movable contact 2 is in the first reference position. In the state of Figure 25, the spring assemblies 13A and 13B apply a force to the connecting assemblies 15A and 15B, which holds the connecting assemblies 15A and 15B against the stop associated with the frame 5. More precisely, the spring assemblies 13A and 13B push the pin 85 against the inner ends 112 and 142 of the slots 151B and 152B of the cam portions 151 and 152, thereby causing rotation of the shafts 11 and 12.

[0117] Therefore, after the dead point, the movement of the two axes 11 and 12 is no longer controlled by the operator, but is determined solely by the action of the spring assemblies 13A and 13B.

[0118] Grounding switches can be easily implemented at the industrial level. Therefore, similar devices using existing technology can be easily manufactured at a competitive cost.

Claims

1. A grounding switch (1) for a medium-voltage electrical switching device, wherein, The grounding switch includes: - a plurality of movable contacts (2) and a plurality of fixed contacts (3); - a frame (5) supporting a rotation application mechanism (4) for rotating the movable contacts (2) between a first reference position and a second reference position, wherein at the first reference position the movable contacts are separated from the fixed contacts (3) and at the second reference position the movable contacts are electrically connected to the fixed contacts (3), wherein the rotation application mechanism includes a first shaft (11), the movable contacts (2) being rigidly mounted on the first shaft, the first shaft (11) rotating about a longitudinal axis (101) in a closing direction (W1) where the movable contacts (2) reach the second reference position and in an opening direction (W2) where the movable contacts (2) reach the first reference position, characterized in that the rotation application mechanism (4) includes: - a second shaft (12), the second shaft being coaxial with the first shaft (11) and capable of being connected to an operating mechanism for controlling the second shaft (12), wherein the The first shaft (11) is hollow and defines a longitudinal cavity, the second shaft (12) is at least partially disposed within the longitudinal cavity, - a first connecting device (15A, 15B) for the first shaft (11) and the second shaft (12), the first connecting device being configured such that the second shaft (12) is free to rotate relative to the first shaft (11) at least during a first rotation phase when the second shaft (12) rotates according to the closed direction (W1), and after the first rotation phase is completed, the first connecting device (15A, 15B) rotatably connects the first shaft (11) and the second shaft (12); - a spring device (13A, 13B) operatively connected to the first connecting device (15A, 15B), wherein the spring device (13A, 13B) is loaded during the first rotation phase and releases the elastic energy of the spring device onto the first shaft (11) and the second shaft (12) via the first connecting device (15A, 15B) when the first rotation phase has been completed.

2. The grounding switch (1) according to claim 1, wherein, In the first reference position, the active contact (2) is located on the first reference plane (PV), and in the second reference position, the active contact (2) is substantially located on the second reference plane (PH), wherein the first reference plane and the second reference plane are orthogonal to each other.

3. The grounding switch (1) according to claim 1 or 2, wherein, The frame (5) includes a main wall (51) and two side walls (52, 53) extending from the main wall (51) at opposite ends so as to face each other. The main wall (51) includes an inner surface (51A) facing the rotation application mechanism (4). The two side walls (52, 53) support the first axis (11) and the second axis (12) at opposite ends such that the longitudinal axis (101) is substantially parallel to the main wall (51).

4. The grounding switch (1) according to claim 1 or 2, wherein, The first connecting device (15A, 15B) includes a first connecting assembly (15A) and a second connecting assembly (15B) operatively arranged at opposite end portions of the first shaft (11) and the second shaft (12), and the spring device (13A, 13B) includes a first spring assembly (13A) and a second spring assembly (13B), wherein the first connecting assembly (15A) interacts with the first spring assembly (13A), and the second connecting assembly (15B) interacts with the second spring assembly (13B).

5. The grounding switch (1) according to claim 1 or 2, wherein, The first coupling device includes at least one coupling assembly (15A, 15B), the coupling assembly comprising: - a first cam portion (151), the first cam portion being rigidly connected to the first shaft (11) and including a first slot (151B) extending through the entire longitudinal thickness of the first cam portion (151), the first slot (151B) extending according to a curved profile; - a second cam portion (152), the second cam portion being rigidly connected to the second shaft (12) and including extending through the entire longitudinal thickness of the second cam portion (152). The second slot (152B) extends according to a curved profile, and the first slot (151B) and the second slot (152B) only partially overlap with respect to the side view of the rotation application mechanism (4); a drive pin (85) is inserted longitudinally into the first slot (151B) and the second slot (152B), wherein the drive pin (85) is operatively connected to the spring assembly (13A, 13B) of the spring device, such that the spring assembly (13A) is loaded or unloaded according to the position of the drive pin (85).

6. The grounding switch (1) according to claim 5, wherein, The spring assembly (13A, 13B) includes a rod (131) hinged to the drive pin (85) for rotation about an axis parallel to the longitudinal axis (101), the rod (131) including an abutment portion (131A), a first end (133A) of a spring element (133) abutting the abutment portion, and a second end (133B) of the spring element (133) abutting a portion of the frame (5).

7. The grounding switch (1) according to claim 1 or 2, wherein, The grounding switch (1) further includes a second coupling device (16A, 16B) that operatively connects the second shaft (12) to the first shaft (11) when the movable contact (2) reaches the second reference position, and during rotation along the disconnection direction (W2), the second coupling device (16A, 16B) rigidly connects the first shaft (11) to the second shaft (12).

8. The grounding switch (1) according to claim 7, wherein, The second connecting device includes: - a plurality of push plates (161A, 161B) rigidly connected to the outer surface of the second shaft (12), wherein each of the plurality of push plates (161A, 161B) includes a longitudinal edge (165A, 165B); - a plurality of openings (161, 162) defined through the outer surface of the first shaft (11), each of the plurality of openings (161, 162) including a longitudinal edge (166A, 166B); wherein, when the movable contact (2) reaches the second reference position, the longitudinal edge (165A, 165B) of each push plate (161A, 161B) abuts against the corresponding longitudinal edge (166A, 166B) of the corresponding opening (161, 162).

9. The grounding switch (1) according to claim 1 or 2, wherein, The grounding switch (1) includes an elastic device (60) operatively arranged between the frame (5) and the first shaft (11), wherein the elastic device (60) applies a force opposite to the closing motion to prevent any oscillation or vibration of the first shaft (11) during the first rotational phase of the second shaft (12) along the closing direction (W1).

10. The grounding switch (1) according to claim 5, wherein, The grounding switch (1) is provided with damping devices (17A, 17B) mounted on the frame (5) to dampen the closing motion of the first shaft (11) and the second shaft (12) when the movable contact (2) reaches the second reference position.

11. The grounding switch (1) according to claim 10, wherein, The damping device (17A, 17B) includes a first damping component (17A) that interacts with a first connecting component (15A) of the first connecting device and a second damping component (17B) that interacts with a second connecting component (15B) of the first connecting device, wherein each of the first damping component (17A) and the second damping component (17B) is mounted on the frame (5).

12. The grounding switch (1) according to claim 11, wherein, At least one of the first damping assembly (17A) and the second damping assembly (17B) includes a first damper element (121) and a second damper element (122), the first damper element and the second damper element providing abutment surfaces to the first cam portion (151) and the second cam portion (152) of the corresponding coupling assembly (15A, 15B), respectively.

13. The grounding switch (1) according to claim 1 or 2, wherein, The grounding switch (1) includes stop devices (18A, 18B) connected to the frame (5) to stop the disconnection movement of the first shaft (11) and the second shaft (12) when the active contact (2) reaches the first reference position.

14. The grounding switch (1) according to claim 5, wherein, The drive pin (85) is inserted into a rotating bushing, which is rotatable relative to the same drive pin (85) that slides on the surfaces of the first slot (151B) and the second slot (152B).

15. The grounding switch (1) according to claim 5, wherein, A pin retainer portion (90) is mounted on the first shaft (11) in a longitudinal position, the longitudinal position being included between the first cam portion (151) rigidly connected to the first shaft (11) and the second cam portion (152) rigidly connected to the second shaft (12), the pin retainer portion (90) including a through hole into which a segment (85A) of the drive pin (85) is inserted.

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