Bypass switch matched with ring main unit

Abstract

This invention discloses a bypass switch for use with a ring main unit, comprising a base frame, a circuit switching unit, and an operation control mechanism. The circuit switching unit includes a drive shaft, a moving contact, a first stationary contact, and a second stationary contact. The operation control mechanism includes a handle assembly, an operating shaft, a first drive crank arm, a driven crank arm, a sliding shaft, a limit shaft, a splitting spring, and a linkage pull plate assembly. A fixing plate is fixed on the base frame. The handle assembly is connected to the operating shaft. The driven crank arm is connected to the drive shaft via the linkage pull plate assembly. The two ends of the splitting spring are connected to the sliding shaft and the limit shaft, respectively. A damping and position holding structure is provided near the end of the first limit hole. A limit element is provided on the first drive crank arm. Through structural optimization, this invention enables the rapid splitting and closing of the moving contact with a single splitting spring. The end damping and position holding structure achieves impact absorption and position self-locking. The structure is compact, the operation is reliable, and it has good practicality.

Description

Technical Field

[0001] This invention belongs to the field of electrical switches, and specifically relates to a bypass switch for use with ring main units. Background Technology

[0002] Ring main units (RNBs) are critical nodes in power distribution networks, typically containing load switches, circuit breakers, and other circuit-connecting devices. When these switches require maintenance or malfunction, power outages are often necessary, impacting power supply reliability. Therefore, bypass switches are widely used in RNB solutions. By temporarily connecting a bypass circuit, faulty or maintenance equipment can be isolated without power interruption. Existing bypass switch operating mechanisms often employ manual direct-drive of the moving contact. The opening and closing speeds are significantly affected by the operator's force and speed, easily leading to arcing or contact bounce during contact opening and closing, impacting the switch's electrical life and reliability. Some bypass switches incorporate energy storage springs in their operating control mechanisms to store and release energy during opening and closing. However, this typically requires two energy storage springs and involves numerous related components and transmission links, increasing structural complexity. Furthermore, unreasonable limit structures can easily lead to insufficient or overshoot of the moving contact, affecting contact pressure and breaking capacity. Summary of the Invention

[0003] The purpose of this invention is to provide a bypass switch for ring main units that is compact in structure, has few transmission links, and can achieve fast and stable opening and closing with a single opening and closing spring, while maintaining stable performance. It can effectively absorb the impact of the circuit breaker and achieve position self-locking while achieving fast opening and closing, thereby improving the electrical life and operational reliability of the switch.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] This invention provides a bypass switch for a ring main unit, comprising a base frame, a circuit switching unit mounted on the base frame, and an operation control mechanism. The circuit switching unit includes a drive shaft rotatably mounted on the base frame, a moving contact linked to the drive shaft, and a first stationary contact and a second stationary contact fixed at opposite positions on the base frame. One end of the moving contact is hinged to the first stationary contact. The drive shaft is driven to rotate by the operation control mechanism to connect and separate the moving contact from the second stationary contact. The operation control mechanism includes a handle assembly, an operation shaft, a first drive crank arm, a driven crank arm, a sliding shaft, a limit shaft, a splitting spring, and a linkage pull plate assembly. A fixing plate is fixed laterally on the base frame. The handle assembly is connected to the operation shaft, and the operation shaft is rotatably mounted. On the fixed plate, one end of the first driving crank arm is fixedly connected to the operating shaft, and the other end is fixed to the limiting shaft. One end of the driven crank arm is movably sleeved on the operating shaft, and the other end is connected to the sliding shaft. The driven crank arm is connected to the driving shaft through a linkage pull plate assembly. The two ends of the split-opening tension spring are respectively connected to the sliding shaft and the limiting shaft. The fixed plate is provided with a first limiting hole and a second limiting hole. The sliding shaft is installed on the fixed plate and movably passes through the first limiting hole, so that it can move relative to the fixed plate along the trajectory of the first limiting hole. A damping and position holding structure acting on the sliding shaft is provided near the end of the first limiting hole. The first driving crank arm is provided with a limiting member that cooperates with the second limiting hole.

[0006] Preferably, the driven crank arm and the sliding shaft are connected by a sliding connection structure so that the sliding shaft can move along the length direction of the driven crank arm; the damping and position holding structure is as follows: the first limiting hole is provided with curved hole sections protruding away from the center direction of the operating shaft at positions near its two ends. When the sliding shaft moves and passes through the curved hole sections, it overcomes the tension of the opening and closing springs and reaches the end of the first limiting hole after passing through the curved hole sections, so as to limit the sliding shaft at the extreme position of closing or opening.

[0007] Preferably, the sliding connection structure is as follows: a strip-shaped hole is provided on the driven crank arm along its length direction, and the sliding shaft extends into the strip-shaped hole and can slide relative to it along the length direction of the strip-shaped hole.

[0008] Preferably, the curved hole section is arc-shaped and has a smooth transition with the first limiting hole; the end of the first limiting hole is provided with a micro-locking groove adjacent to the curved hole section, the micro-locking groove is recessed in the direction of the drive shaft, and the sliding shaft slides into the micro-locking groove when it moves to the limit position of closing or opening.

[0009] Preferably, the fixed plate is fixed with guide plates at intervals, the guide plates are provided with third limiting holes that are opposite to the first limiting holes and have the same shape, and the sliding shaft is fitted with a first roller and a second roller that are respectively in rolling cooperation with the hole walls of the first limiting hole and the third limiting hole.

[0010] Preferably, the handle assembly includes an operating handle, a splitting / engaging crank arm, an adjusting link, and a second driving crank arm; the operating handle is rotatably mounted on the base frame via a handle shaft; one end of the splitting / engaging crank arm is fixed to the handle shaft, and the other end is movably connected to one end of the adjusting link; the other end of the adjusting link is movably connected to one end of the second driving crank arm; the other end of the second driving crank arm is fixedly connected to the operating shaft; the adjusting link has an adjustable length structure; the splitting / engaging crank arm has a first strip-shaped hole along its length direction, and the second driving crank arm has a second strip-shaped hole along its length direction; both ends of the adjusting link are connected to the first strip-shaped hole and the second strip-shaped hole respectively via a first connecting pin and a second connecting pin.

[0011] Preferably, the adjusting rod includes an adjusting screw, an adjusting sleeve, and a locking nut. One end of the adjusting screw is provided with a stud section, which is screwed into an axial threaded hole on the adjusting sleeve. The locking nut is screwed into the stud and abuts against the adjusting sleeve. The first connecting pin and the second connecting pin are respectively fixedly connected to the ends of the adjusting sleeve and the adjusting screw that are far apart from each other.

[0012] Preferably, the linkage pull plate assembly includes a first pull plate and a second pull plate. One end of the first pull plate is hinged to one end of the second pull plate, the other end of the first pull plate is fixedly connected to the drive shaft, and the other end of the second pull plate is hinged to the middle of the driven crank arm. A contact crank arm is fixed on the drive shaft. The contact crank arm is hinged to one end of the arc-shaped pull plate, and the other end of the arc-shaped pull plate is hinged to the connecting seat. The connecting seat is fixed to the moving contact.

[0013] Preferably, an arc-extinguishing device is fixed near the second stationary contact. The arc-extinguishing device includes an insulating support and multiple arc-extinguishing grid plates. The insulating support is fixedly connected to the second stationary contact and includes a mounting shaft. Multiple slots are spaced apart along the length of the mounting shaft. The arc-extinguishing grid plates are provided with slots. Multiple arc-extinguishing grid plates are engaged with the slots one by one through their slots and are spaced apart to form multiple arc-extinguishing gaps. The middle part of the arc-extinguishing grid plate is bent to form at least one arc-shaped bend-stop portion, and the length of the bend-stop portion is equal to the width of the arc-extinguishing grid plate.

[0014] Preferably, the limiting member is a limiting stop bar fixed on the first drive crank arm, and the limiting stop bar and the limiting shaft are two independent components; or the limiting member and the limiting shaft are an integral part.

[0015] The positive effects of this invention are as follows: In the bypass switch for the ring main unit of this invention, only one opening and closing spring is used to simultaneously achieve energy storage and rapid opening and closing. Combined with the sliding connection structure between the strip hole on the driven crank arm and the sliding shaft, over-constraint and motion interference are eliminated. The overall number of parts is small, assembly is convenient, and the cost is low. Moreover, through the stretching and energy storage of the opening and closing spring and the instantaneous release after passing the dead point, the opening and closing speed of the moving contact is determined by the spring characteristics and is independent of the speed at which the operator turns the handle. This effectively suppresses contact bounce and arcing, significantly improving electrical life. It has both breaking capacity and stopping capacity; in addition, by setting up a damping and position holding structure, when the sliding shaft moves to the end of its stroke, the bending hole section uses the tension of the opening and closing spring to generate a damping effect, absorbing part of the kinetic energy before it reaches the end position, avoiding the moving contact from hitting the second stationary contact at high speed, thereby reducing contact bounce; at the same time, after the sliding shaft passes through the bending hole section, it is pressed into the micro-locking groove by the opening and closing spring to achieve the locking function, so that it cannot retract on its own even when subjected to vibration or external force, ensuring the stable holding of the closing or opening position, and without the need to add any additional locking pin parts, the structure is simple and highly reliable. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art are briefly introduced below. Similar elements or parts in the drawings are generally identified by similar reference numerals. The elements or parts in the drawings are not necessarily drawn to scale.

[0017] Figure 1 This is a schematic diagram of the bypass switch used in the ring main unit of the present invention.

[0018] Figure 2 This is a schematic diagram of the internal structure of the bypass switch used in the ring main unit of this invention.

[0019] Figure 3 This is a schematic diagram of the operation control mechanism (including the fixing plate) in this invention.

[0020] Figure 4 This is a schematic diagram of the operation control mechanism (with the fixed plate removed) from another perspective in this invention.

[0021] Figure 5 This is a schematic diagram of the arc-extinguishing device (including the second stationary contact) in this invention.

[0022] Figure 6 for Figure 5 A disassembly attempt of the arc-extinguishing device shown.

[0023] Figure 7 This is a front view of the first limiting hole in this invention.

[0024] Figure 8 This is a schematic diagram of the adjusting linkage in this invention.

[0025] Figure 9 This is a front view of the adjusting linkage in this invention.

[0026] Figure 10 For along Figure 9 A sectional view cut along line AA.

[0027] The reference numerals in the figure are as follows: base frame 1; circuit switching unit 2; drive shaft 21; moving contact 22; first stationary contact 23; second stationary contact 24; operation control mechanism 3; handle assembly 31; operating handle 311; splitting crank arm 312; adjusting connecting rod 313; adjusting screw 3131; adjusting screw sleeve 3132; locking nut 3133; stud section 3134; second drive crank arm 314; handle shaft 315; first strip hole 316; second strip hole 317; first connecting pin 318; second connecting pin 319; operating shaft 32; first drive crank arm 33; driven crank arm 34; strip Hole 341; sliding shaft 35; limiting shaft 36; splitting and engaging tension spring 37; linkage pull plate assembly 38; first pull plate 381; second pull plate 382; fixing plate 39; first limiting hole 391; second limiting hole 392; bent hole section 393; micro-locking groove 394; guide plate 395; third limiting hole 396; first roller 397; second roller 398; contact crank arm 4; arc-shaped pull plate 41; connecting seat 42; arc extinguishing device 5; insulating bracket 51; mounting shaft part 511; slot 512; arc extinguishing grid plate 52; arc inlet 520; bayonet 521; bent arc-blocking part 522; limiting component 6. Detailed Implementation

[0028] The embodiments of the technical solution of the present invention will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore merely examples and should not be used to limit the scope of protection of the present invention.

[0029] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0030] The bypass switch structure for the ring main unit in this embodiment of the invention is as follows: Figures 1 to 10 As shown, it includes a base frame 1, a circuit switching unit 2 and an operation control mechanism 3 mounted on the base frame 1. The base frame 1 serves as the mounting foundation for the entire switch and is typically made of welded or riveted metal plates, possessing sufficient strength and rigidity to fix the switch to the ring main unit.

[0031] like Figure 2As shown, the circuit switching unit 2 includes a drive shaft 21 rotatably mounted on a base frame 1, a moving contact 22 linked to the drive shaft 21, and a first stationary contact 23 and a second stationary contact 24 fixed at opposite positions on the base frame 1. The first stationary contact 23 is typically connected to the power supply side, and the second stationary contact 24 is connected to the load side, or vice versa, depending on the main circuit wiring. The drive shaft 21 is supported on the base frame 1 by a bearing seat and can rotate flexibly around its own axis. One end of the moving contact 22 is hinged to the first stationary contact 23, allowing the moving contact 22 to swing within a certain angle range around the hinge point. The drive shaft 21 is driven to rotate by the operation control mechanism 3 to connect (close) and disconnect (open) the moving contact 22 and the second stationary contact 24.

[0032] See Figure 3 and Figure 4 As shown, the operation control mechanism 3 includes a handle assembly 31, an operating shaft 32, a first drive crank arm 33, a driven crank arm 34, a sliding shaft 35, a limiting shaft 36, a splitting tension spring 37, and a linkage pull plate assembly 38. A fixing plate 39 is fixed laterally on the base frame 1. The handle assembly 31 is connected to the operating shaft 32. The operating shaft 32 is rotatably mounted on the fixing plate 39 and is typically supported by rolling bearings or sliding bearings. The user drives the operating shaft 32 to rotate by operating the handle assembly 31. One end of the first drive crank arm 33 is fixedly connected to the operating shaft 32 (e.g., by key connection or welding), and the other end is fixed to the limiting shaft 36. One end of the driven crank arm 34 is movably sleeved on the operating shaft 32, allowing the driven crank arm 34 to rotate relative to the operating shaft 32. The other end of the driven crank arm 34 is connected to the sliding shaft 35. The driven crank arm 34 is connected to the sliding shaft 35. The linkage pull plate assembly 38 is connected to the drive shaft 21, converting the swing of the driven crank arm 34 into the rotation of the drive shaft 21. The two ends of the split tension spring 37 are respectively connected to the sliding shaft 35 and the limiting shaft 36. The fixed plate 39 is provided with a first limiting hole 391 and a second limiting hole 392. The sliding shaft 35 is mounted on the fixed plate 39 and movably passes through the first limiting hole 391, so that it can move relative to the fixed plate 39 along the trajectory of the first limiting hole 391. The first limiting hole 391 is used to guide the movement trajectory of the sliding shaft 35 and limit the movement stroke of the sliding shaft 35. Near the end of the first limiting hole 391, there is a damping and position holding structure acting on the sliding shaft 35. This structure can absorb excess kinetic energy when the sliding shaft 35 moves to the limit position and provide a stable holding force to prevent backing.

[0033] With the above structure, when the operator turns the handle assembly 31, the operating shaft 32 drives the first drive crank arm 33 to rotate. The first drive crank arm 33 applies tension to the sliding shaft 35 through the limit shaft 36, and at the same time stretches the opening and closing spring 37 to store energy. When the dead point is passed, the opening and closing spring 37 releases energy, driving the driven crank arm 34 to rotate rapidly. The driven crank arm 34 then drives the drive shaft 21 to rotate through the linkage pull plate assembly 38, finally realizing the rapid closing or opening of the moving contact 22 and the second stationary contact 24. With only one opening and closing spring 37, the structure is simple, the transmission links are few, and the operation is stable.

[0034] like Figure 4 As shown, the driven crank arm 34 and the sliding shaft 35 are connected by a sliding connection structure, so that the sliding shaft 35 can move along the length direction of the driven crank arm 34. When the driven crank arm 34 swings, the sliding shaft 35 is constrained by the first limiting hole 391 to move along a specific trajectory, and at the same time, the connection point between it and the driven crank arm 34 is constantly changing its relative position. The sliding connection structure allows the sliding shaft 35 to slide freely along the length of the driven crank arm 34, thereby eliminating motion interference and ensuring smooth operation of the mechanism. Simultaneously, a damping and position-holding structure is designed in conjunction with this structure. Specifically, the first limiting hole 391 has curved hole sections 393 protruding away from the center of the operating shaft 32 near its two ends. The curved hole sections 393 can be arc-shaped, with their protrusion direction away from the center of the operating shaft 32, i.e., bending away from the axis of the operating shaft 32. When the sliding shaft 35 passes the dead point and moves to the curved hole section 393 under the drive of the opening and closing spring 37, the direction of the curved hole section 393 forms an angle (or even the opposite) with the direction of the tension of the opening and closing spring 37. The sliding shaft 35 needs to overcome the tension of the opening and closing spring 37 to continue moving forward, thus generating a certain damping effect and appropriately absorbing the kinetic energy before reaching the position. During the closing phase, this prevents the moving contact 22 from impacting the stationary contact at excessive speed. When the sliding shaft 35 passes through the curved hole section 393 and reaches the end (physical endpoint) of the first limiting hole 391, the tension spring 37 still maintains a certain tension force. This tension force presses the sliding shaft 35 tightly against the end of the hole, forming a stable position holding. Due to the presence of the curved hole section 393, if you want the sliding shaft 35 to retract from the end of the hole, it must pass through the curved hole section 393 again in the opposite direction, which also requires overcoming the tension spring force, thus achieving a self-locking effect. This structure does not add any extra parts; it achieves damping buffering and positioning locking simply by changing the shape of the first limiting hole.

[0035] The sliding connection structure is further optimized as follows: a strip-shaped hole 341 is formed along the length of the driven crank arm 34, and the sliding shaft 35 extends into the strip-shaped hole 341 and can slide relative to it along the length of the strip-shaped hole 341. The portion of the sliding shaft 35 passing through the strip-shaped hole 341 is a smooth shaft (or a bearing is installed thereon) to ensure smooth sliding. When the sliding shaft 35 moves along the trajectory of the first limiting hole 391, it slides within the strip-shaped hole 341 and abuts against the hole wall of the strip-shaped hole 341, thereby driving the driven crank arm 34 to swing. This structure is simple, reliable, easy to manufacture, and can effectively compensate for manufacturing errors.

[0036] like Figure 7 The curved section 393 is arc-shaped and has a smooth transition connection with the main track of the first limiting hole 391 to reduce the impact and wear when the sliding shaft 35 moves, and to avoid scratching or jamming caused by sharp corners. The end of the first limiting hole 391 is also provided with a micro-locking groove 394 adjacent to the curved section 393. The micro-locking groove 394 is recessed in the direction of the drive shaft 21 (that is, opposite to the protruding direction of the curved section 393). When the sliding shaft 35 moves to the limit position of closing or opening, the sliding shaft 35 slides into the micro-locking groove 394, producing a "click" feeling of being put into position; since the concave direction of the micro-locking groove 394 is opposite to the convex direction of the curved hole section 393, the sliding shaft 35 first climbs over the apex of the curved hole section 393, and then slides down into the micro-locking groove 394. At the bottom of the micro-locking groove 394, it is pressed by the opening and closing tension spring 37 and blocked by the groove wall, and cannot be easily withdrawn; this structure provides a clear feeling of being put into position and significantly improves the vibration resistance; the micro-locking groove 394 is preferably designed as an arc groove.

[0037] In a preferred embodiment, to address the problem of tilting and jamming of the sliding shaft 35 due to uneven force during movement and to further improve its motion stability, a guide plate 395 is fixedly fixed at intervals on the fixed plate 39. The guide plate 395 is parallel to the fixed plate 39, and a third limiting hole 396 with the same shape and position as the first limiting hole 391 is provided on the guide plate 395. The guide plate 395 is connected to the fixed plate 39 by four metal isolation columns, the length of which determines the distance between the fixed plate 39 and the guide plate 395. A first roller 397 and a second roller 398 are sleeved on the sliding shaft 35, wherein the first roller 397... The first roller 397 is located within the first limiting hole 391 and rolls in engagement with the wall of the first limiting hole 391. The second roller 398 is located within the third limiting hole 396 and rolls in engagement with the wall of the third limiting hole 396. Through this structure, when the sliding shaft 35 moves under the combined action of the split-opening tension spring 37 and the driven crank arm 34, the first roller 397 and the second roller 398 roll in the first and third limiting holes respectively. This not only provides two support points for the sliding shaft 35 at a certain distance, effectively resisting the tilting torque generated by lateral forces and avoiding sliding friction between the sliding shaft 35 and the walls of the first and third limiting holes, but also reduces motion resistance through rolling engagement, making the movement of the sliding shaft 35 smoother. At the same time, the first limiting hole 391 and the third limiting hole 396 jointly constrain the radial position of the sliding shaft 35, improving the motion stability of the driven crank arm 34 and the entire operating control mechanism 3. To axially limit the sliding shaft 35 and prevent its axial movement, a limiting component (such as a snap ring, not shown in the figure) is provided on the sliding shaft 35. This limiting component forms an axial stop with the side of the fixed plate 39 or guide plate 395, thereby constraining the axial degree of freedom of the sliding shaft 35 to limit its installation on the fixed plate 39 and guide plate 395, preventing it from coming out of the first limiting hole 391 and the third limiting hole 396, ensuring that the sliding shaft 35 always moves smoothly within a preset trajectory, and improving the stability of the mechanism. The first roller 397 and the second roller 398 can be bearings.

[0038] Continue reading Figure 3 and Figure 4The handle assembly 31 includes an operating handle 311, a disengaging crank arm 312, an adjusting rod 313, and a second driving crank arm 314. The operating handle 311 is rotatably mounted on the base frame 1 via a handle shaft 315. One end of the disengaging crank arm 312 is fixed to the handle shaft 315, and the other end is movably connected to one end of the adjusting rod 313. The other end of the adjusting rod 313 is movably connected to one end of the second driving crank arm 314. The other end of the second driving crank arm 314 is fixedly connected to the operating shaft 32. The adjusting rod 313 has an adjustable length and is used to adjust the initial angle and disengaging stroke of the operating handle 311. The disengaging crank arm 312 has a first strip-shaped hole 316 along its length, and the second driving crank arm 314 has a second strip-shaped hole 317 along its length. The two ends of the adjusting rod 313 are respectively connected to the first strip-shaped hole 316 and the second strip-shaped hole 317 via a first connecting pin 318 and a second connecting pin 319.

[0039] Furthermore, combined Figure 3 , Figure 4 and Figures 8 to 10 The adjustable structure of the adjusting rod 313 includes an adjusting screw 3131, an adjusting sleeve 3132, and a locking nut 3133. One end of the adjusting screw 3131 has a stud section 3134, which is screwed into an axial threaded hole on the adjusting sleeve 3132. Rotating the adjusting sleeve 3132 changes the total length of the adjusting rod 313. The locking nut 3133 is screwed into the stud section 3134 and presses against the adjusting sleeve 3132 to lock the adjusted length and prevent loosening due to vibration during use. A first connecting pin 318 and a second connecting pin 319 are fixedly connected (or welded) to the ends of the adjusting sleeve 3132 and the adjusting screw 3131, respectively, at their furthest points. This adjustment method has a simple structure, a large adjustment range, and reliable locking after adjustment.

[0040] Furthermore, the linkage pull plate assembly 38 includes a first pull plate 381 and a second pull plate 382; one end of the first pull plate 381 is hinged to one end of the second pull plate 382, ​​the other end of the first pull plate 381 is fixedly connected to the drive shaft 21, and the other end of the second pull plate 382 is hinged to the middle of the driven crank arm 34; by adopting the form of two pull plates hinged together, it can accommodate the possible spatial misalignment and angular deviation between the driven crank arm 34 and the drive shaft 21, and avoid the jamming or sticking caused by rigid transmission; this structure is conducive to the flexible arrangement of the positions of each component. A contact crank arm 4 is also fixed on the drive shaft 21. The contact crank arm 4 is hinged to one end of the arc-shaped pull plate 41, and the other end of the arc-shaped pull plate 41 is hinged to the connecting seat 42, which is fixed on the moving contact 22. When the drive shaft 21 rotates, the contact crank arm 4 rotates accordingly, pushing or pulling the connecting seat 42 through the arc-shaped pull plate 41, thereby causing the moving contact 22 to swing around its hinge point with the first stationary contact 23. The arc shape of the arc-shaped pull plate 41 can compensate for the trajectory deviation between the hinge point of the drive shaft 21 and the moving contact 22, so that the moving contact 22 always maintains the correct angle during the swing and provides sufficient contact pressure at the closing end position.

[0041] Combination Figure 2 and Figure 5 and Figure 6As shown, in this embodiment, an arc-extinguishing device 5 is fixed near the second stationary contact 24 to quickly extinguish the arc generated when the moving contact 22 breaks with the second stationary contact 24, protecting the contact and improving the breaking capacity of the switch. The arc-extinguishing device 5 includes an insulating bracket 51 and multiple arc-extinguishing grid plates 52. The insulating bracket 51 is fixedly connected to the second stationary contact 24 (e.g., by screws or clips). The insulating bracket 51 is typically injection molded from arc-resistant engineering plastics (such as nylon or polycarbonate). The insulating bracket 51 includes a mounting shaft portion 511, which is elongated and has multiple slots 512 spaced along its length. The cross-sectional shape of the slots 512 matches the slots 521 on the arc-extinguishing grid plates 52. The arc-extinguishing grid plate 52 is stamped from a ferromagnetic material (such as silicon steel sheet) and is flat. A slot 521 is provided at one end of the grid plate 520 away from the arc inlet. The arc inlet 520 has a concave structure, and the second stationary contact 24 extends into the arc inlet 520. The arc enters the arc-extinguishing device 5 from the arc inlet 520. Multiple arc-extinguishing grid plates 52 are engaged one-to-one with multiple slots 512 on the insulating bracket 51 through their slots 521, without the need for screws or welding, making assembly convenient. All arc-extinguishing grid plates 52 are spaced apart to form multiple parallel arc-extinguishing gaps; and each arc-extinguishing grid plate 52 has at least one arc-shaped bend-off portion 522 in the middle, and the length of the bend-off portion 522 is equal to the width of the arc-extinguishing grid plate 52, that is, it extends along the entire width of the arc-extinguishing grid plate 52; when the arc enters the arc-extinguishing device, it is cut off by the arc-extinguishing grid plate 52, the short arc enters the arc-extinguishing gap and is blocked by the bend-off portion 522, increasing the arc path length and accelerating the cooling and extinguishing of the arc; at the same time, the bend-off portion 522 can also buffer the arc, reduce the arc flow rate, and prevent the arc from flowing directly through the arc-extinguishing gap and impacting the mounting shaft portion 511.

[0042] See Figure 3 The first drive crank arm 33 is provided with a limiting member 6 that cooperates with the second limiting hole 392. The limiting member 6 extends into the second limiting hole 392. When the first drive crank arm 33 rotates to the maximum angle with the operating shaft 32, the limiting member 6 contacts the corresponding end of the second limiting hole 392, thereby limiting the further rotation of the first drive crank arm 33 and indirectly limiting the rotation range of the operating shaft 32.

[0043] In one embodiment, the limiting member 6 and the limiting shaft 36 are two independent parts: the limiting shaft 36 is fixed to the first drive crank arm 33 for connecting the split-opening tension spring 37, and the limiting member 6 is fixed to another position of the first drive crank arm 33 and passes through the second limiting hole 392. In another embodiment, the limiting member 6 and the limiting shaft 36 are integrally formed long rods. These long rods pass through the first drive crank arm 33 and are welded and fixed. One end of the rod extends into the second limiting hole 392 as the limiting member 6, and the other end is used to connect the split-opening tension spring 37.

[0044] The following describes in detail the closing and opening processes of this bypass switch, based on the above structure.

[0045] Closing process:

[0046] The initial state is the open position. At this time, the moving contact 22 is separated from the second stationary contact 24, forming a clear disconnection gap. The opening and closing tension spring 37 is in a small tension state. The sliding shaft 35 is located at the open end of the first limiting hole 391 and falls into the micro-locking groove 394 at the open end.

[0047] When the operator moves the handle assembly 31 forward (e.g., clockwise), the operating handle 311 rotates around the handle shaft 315, which drives the second drive arm 314 to rotate via the splitting crank arm 312 and the adjusting linkage 313, thereby driving the operating shaft 32 to rotate. The first drive arm 33, which is fixed to the operating shaft 32, rotates accordingly. Since one end of the splitting tension spring 37 is connected to the limiting shaft 36 and the other end is connected to the sliding shaft 35, when the limiting shaft 36 moves, the splitting tension spring 37 is gradually stretched, and pulls the sliding shaft 35 to slide out of the micro-lock groove 394 at the opening end and pass through the curved hole section 393 at the opening end before advancing along the first limiting hole 391. As the sliding shaft 35 continues to advance and passes the highest point (dead point) of the first limiting hole 391, the angle between the tension direction of the opening and closing spring 37 and the direction of movement suddenly changes. The spring force changes from resistance to power, driving the sliding shaft 35 to accelerate into the latter half of the first limiting hole 391 and pass through the curved hole section 393 of the closing end, finally falling into the micro-locking groove 394 of the closing end. During this process, the sliding shaft 35 drives the driven crank arm 34 to swing rapidly by pushing against the side wall of the strip hole 341. The driven crank arm 34 drives the drive shaft 21 to rotate rapidly through the linkage pull plate assembly 38. The drive shaft 21 drives the moving contact 22 to swing rapidly towards the second stationary contact 24 through the contact crank arm 4 and the arc-shaped pull plate 41, making close contact with the second stationary contact 24 and completing the closing. During the closing phase, when the sliding shaft 35 passes the curved hole section 393, due to its protrusion away from the center of the operating shaft 32, the direction of movement of the sliding shaft 35 forms a significant angle with the direction of the tension force of the opening and closing spring 37. At this time, it needs to overcome part of the spring force to continue moving forward, thus producing a damping effect. This damping absorbs part of the kinetic energy of the rapidly moving contact 22, preventing the contact from impacting at excessive speed. The operator will feel an increase in the resistance of the handle, but this process is brief and smooth.

[0048] Opening process:

[0049] The initial state is the closed position. At this time, the moving contact 22 is in close contact with the second stationary contact 24, and the circuit is connected. The opening and closing tension spring 37 is in the stretched state. The sliding shaft 35 is located at the closing end of the first limiting hole 391 and falls into the micro-locking groove 394 of the closing end; the limiting member 6 is in contact with the other end (closing limit end) of the second limiting hole 392.

[0050] When the operator reverses the lever assembly 31 (e.g., counterclockwise), the operating handle 311 rotates in the opposite direction around the handle shaft 315, which in turn drives the second drive lever 314 to rotate in the opposite direction via the disengagement lever 312 and the adjusting linkage 313, thereby driving the operating shaft 32 to rotate in the opposite direction. The first drive lever 33, which is fixed to the operating shaft 32, rotates in the opposite direction, which pulls the disengagement spring 37 through the limit shaft 36, causing it to stretch further and drive the sliding shaft 35 to move along the first limit hole 391 in the direction of opening. The sliding shaft 35 first needs to overcome the holding force of the micro-lock groove 394 at the closing end and pass through the curved hole section 393 at the corresponding end. During this process, the operating resistance increases slightly.

[0051] As the sliding shaft 35 continues to move in the reverse direction and passes the highest point (dead point) of the first limiting hole 391, the angle between the tension direction of the opening and closing spring 37 and the direction of movement suddenly changes. The force of the opening and closing spring 37 changes from resistance to power, driving the sliding shaft 35 to accelerate and slide in the reverse direction past the rear half of the first limiting hole 391, and after passing the curved hole section 393 of the opening end, it falls into the micro-locking groove 394 of the opening end. During this process, the driven crank arm 34 drives the drive shaft 21 to rotate rapidly in the reverse direction through the linkage pull plate assembly 38. The drive shaft 21 drives the moving contact 22 to quickly leave the second stationary contact 24 through the contact crank arm 4 and the arc-shaped pull plate 41, breaking the circuit. At the same time, the limiting member 6 contacts the other end (opening limit end) of the second limiting hole 392. The electric arc generated during the entire opening process is quickly sucked into the gap of the arc-extinguishing grid plate 52 by the arc-extinguishing device 5 near the second stationary contact 24, is divided into multiple short arcs and cooled and extinguished, effectively protecting the contact from arc erosion.

[0052] For those skilled in the art, other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, these obvious variations or modifications derived from the essential spirit of this invention still fall within the scope of protection of this invention.

Claims

1. A bypass switch for use with a ring main unit, comprising a base frame, a circuit switching unit and an operation control mechanism mounted on the base frame, wherein the circuit switching unit includes a drive shaft rotatably mounted on the base frame, a moving contact linked to the drive shaft, and a first stationary contact and a second stationary contact fixed at opposite positions on the base frame; one end of the moving contact is hinged to the first stationary contact, and the drive shaft is driven to rotate by the operation control mechanism to drive the moving contact to connect and separate from the second stationary contact; characterized in that: The operation control mechanism includes a handle assembly, an operating shaft, a first drive crank arm, a driven crank arm, a sliding shaft, a limiting shaft, a splitting spring, and a linkage pull plate assembly. A fixed plate is horizontally fixed on the base frame. The handle assembly is connected to the operating shaft, which is rotatably mounted on the fixed plate. One end of the first drive crank arm is fixedly connected to the operating shaft, and the other end is fixed to the limiting shaft. One end of the driven crank arm is movably sleeved on the operating shaft, and the other end is connected to the sliding shaft. The driven crank arm is connected to the drive shaft through the linkage pull plate assembly. Both ends of the splitting spring are connected to the sliding shaft and the limiting shaft, respectively. The fixed plate is provided with a first limiting hole and a second limiting hole. The sliding shaft is mounted on the fixed plate and movably passes through the first limiting hole, allowing it to move relative to the fixed plate along the trajectory of the first limiting hole. A damping and position-holding structure acting on the sliding shaft is provided near the end of the first limiting hole. The first drive crank arm is provided with a limiting member that cooperates with the second limiting hole.

2. The bypass switch for the ring main unit according to claim 1, characterized in that: The driven crank arm and the sliding shaft are connected by a sliding connection structure so that the sliding shaft can move along the length direction of the driven crank arm; the damping and position holding structure is as follows: the first limiting hole is provided with curved hole sections protruding away from the center direction of the operating shaft at the positions near its two ends. When the sliding shaft moves and passes through the curved hole section, it overcomes the tension of the opening and closing spring, and reaches the end of the first limiting hole after passing through the curved hole section, so as to limit the sliding shaft at the extreme position of closing or opening.

3. The bypass switch for the ring main unit according to claim 2, characterized in that: The sliding connection structure is as follows: a strip-shaped hole is provided on the driven crank arm along its length direction, and the sliding shaft extends into the strip-shaped hole and can slide relative to it along the length direction of the strip-shaped hole.

4. The bypass switch for the ring main unit according to claim 2, characterized in that: The curved section is arc-shaped and has a smooth transition with the first limiting hole; the end of the first limiting hole is provided with a micro-locking groove adjacent to the curved section, the micro-locking groove is recessed in the direction of the drive shaft, and the sliding shaft slides into the micro-locking groove when it moves to the limit position of closing or opening.

5. The bypass switch for the ring main unit according to claim 3, characterized in that: The fixed plate is fixed with guide plates at intervals. The guide plates are provided with third limiting holes that are opposite to the first limiting holes and have the same shape. The sliding shaft is fitted with a first roller and a second roller that are respectively in rolling cooperation with the hole walls of the first limiting hole and the third limiting hole.

6. The bypass switch for the ring main unit according to claim 1, characterized in that: The handle assembly includes an operating handle, a splitting / engaging crank arm, an adjusting linkage, and a second driving crank arm. The operating handle is rotatably mounted on the base frame via a handle shaft. One end of the splitting / engaging crank arm is fixed to the handle shaft, and the other end is movably connected to one end of the adjusting linkage. The other end of the adjusting linkage is movably connected to one end of the second driving crank arm, and the other end of the second driving crank arm is fixedly connected to the operating shaft. The adjusting linkage has an adjustable length. The splitting / engaging crank arm has a first slot along its length, and the second driving crank arm has a second slot along its length. Both ends of the adjusting linkage are connected to the first slot and the second slot respectively via a first connecting pin and a second connecting pin.

7. The bypass switch for the ring main unit according to claim 6, characterized in that: The adjusting linkage includes an adjusting screw, an adjusting sleeve, and a locking nut. One end of the adjusting screw is provided with a stud section, which is screwed into an axial threaded hole on the adjusting sleeve. The locking nut is screwed into the stud and abuts against the adjusting sleeve. The first connecting pin and the second connecting pin are respectively fixedly connected to the ends of the adjusting sleeve and the adjusting screw that are far apart from each other.

8. The bypass switch for the ring main unit according to claim 1, characterized in that: The linkage pull plate assembly includes a first pull plate and a second pull plate. One end of the first pull plate is hinged to one end of the second pull plate, and the other end of the first pull plate is fixedly connected to the drive shaft. The other end of the second pull plate is hinged to the middle of the driven crank arm. A contact crank arm is fixed on the drive shaft. The contact crank arm is hinged to one end of the arc-shaped pull plate, and the other end of the arc-shaped pull plate is hinged to the connecting seat. The connecting seat is fixed to the moving contact.

9. The bypass switch for the ring main unit according to claim 1, characterized in that: An arc-extinguishing device is fixed near the second stationary contact. The arc-extinguishing device includes an insulating support and multiple arc-extinguishing grid plates. The insulating support is fixedly connected to the second stationary contact and includes a mounting shaft. Multiple slots are spaced apart along the length of the mounting shaft. The arc-extinguishing grid plates are provided with slots. Multiple arc-extinguishing grid plates are engaged with the slots one by one through their slots and are spaced apart to form multiple arc-extinguishing gaps. The middle part of the arc-extinguishing grid plate is bent to form at least one arc-shaped bend-stop portion, and the length of the bend-stop portion is equal to the width of the arc-extinguishing grid plate.

10. The bypass switch for the ring main unit according to claim 1, characterized in that: The limiting component is a limiting stop bar fixed on the first drive crank arm, and the limiting stop bar and the limiting shaft are two independent components; or the limiting component and the limiting shaft are an integral part.

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