A balance spring assembly for a disconnector

Abstract

Embodiments of the present disclosure provide a balance spring assembly for a disconnect switch (200). The balance spring assembly includes: a push rod (101) partially and coaxially disposed in a knife blade (201) of the disconnect switch (200), the knife blade being rotatable about a first axis (202) to change an operating state of the disconnect switch (200), a first end of the push rod (101) being fixed to a second axis (103) to enable the push rod (101) to rotate about the second axis (103); and a spring (102) disposed in the knife blade (201) and surrounding the push rod (101), the spring (102) being held between a second end of the push rod (101) and an end of the knife blade (201) adjacent to the first axis (202), wherein the second axis (103) is disposed parallel to the first axis (202) to enable the push rod (101) to axially move in the knife blade (201) as the knife blade (201) rotates, thereby compressing or decompressing the spring (102). By disposing the balance spring assembly at least partially in the knife blade (201) of the disconnect switch (200), only one set of springs (102) is required. In addition, no additional components such as protection tubes, auxiliary springs, and some connecting elements are needed. Thus, the manufacturing and assembly costs are significantly reduced. In addition, with this arrangement, when the knife blade (201) rotates from the open position to the closed position, the spring (102) can fully operate throughout the process.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to a disconnect switch, and more particularly, to a balance spring assembly for a disconnect switch. Background Art

[0002] A disconnect switch is a switching device that operates when current does not flow through the power system. The opening and closing operations of the disconnect switch are both performed when current does not flow through the circuit. High-voltage disconnect switches are used in substations to allow isolation of equipment such as transformers and circuit breakers. Generally, disconnect switches are not used for circuit control but for isolation. The disconnect switch can be activated automatically or manually.

[0003] One type of disconnect switch is a vertical-break disconnect switch. The vertical-break disconnect switch typically includes three poles, and each pole typically includes a frame, a rotating insulator, and two support insulators on which a blade is mounted. For example, the blade can be driven by a drive unit that rotates about its longitudinal axis to close the circuit on a fixed contact located on a lateral insulator.

[0004] Due to the mass of the blade, the disconnect switch often requires a large driving force during the opening or closing process, which may cause a huge impact on the fixed contact. To reduce the driving force and the impact on the fixed contact, a balance spring assembly can be provided between the blade and the base on which the blade is mounted. In traditional solutions, the balance spring assembly typically includes two sets of springs, and the blade is usually disposed between the two sets of springs. To protect the springs from erosion and ensure their operation, some additional components, such as protective tubes, auxiliary springs, and some connection units, need to be provided for each spring. Therefore, assembling the spring assembly is not only time-consuming but also inefficient. In addition, due to the position of the springs relative to the blade, the traditional balance spring assembly cannot fully play its intended role. Summary of the Invention

[0005] Embodiments of the present disclosure provide a balance spring assembly for a disconnect switch to at least partially solve the above and other potential problems.

[0006] In a first aspect, there is provided a balance spring assembly for a disconnect switch. The balance spring assembly includes: a push rod, the push rod being partially and coaxially disposed in a blade of the disconnect switch, the blade being rotatable about a first axis to change an operating state of the disconnect switch, a first end of the push rod being fixed to a second axis to enable the push rod to rotate about the second axis; and a spring disposed in the blade and surrounding the push rod, the spring being held between a second end of the push rod and an end of the blade adjacent to the first axis, wherein the second axis is disposed parallel to the first axis to enable the push rod to axially move in the blade as the blade rotates, thereby compressing or decompressing the spring.

[0007] By disposing the balance spring assembly at least partially within the blade of the disconnect switch, only one set of springs is required. In addition, no additional components such as protective tubes, auxiliary springs, and some connecting elements are needed. Thereby, the manufacturing and assembly costs are significantly reduced. Moreover, with this arrangement, when the blade rotates from the open position to the closed position, the spring can fully function throughout the process.

[0008] In some embodiments, the balance spring assembly further includes a retaining block disposed at the second end of the push rod to hold one end of the spring. Thereby, the compressive force of the spring can be applied on a surface rather than a point, thus improving the reliability of the balance spring assembly.

[0009] In some embodiments, the balance spring assembly further includes an insulating ring coaxially disposed around the retaining block to provide insulation and guidance between the retaining block and the blade. With this arrangement, the insulating ring can provide electrical insulation between the blade and the balance spring assembly. Moreover, the sliding of the retaining block within the blade can be smoother.

[0010] In some embodiments, the balance spring assembly further includes a flange disposed at the end of the blade to hold one end of the spring. Thereby, the spring can be well held between the retaining block and the flange to further improve the reliability of the balance spring assembly.

[0011] In some embodiments, the flange includes a through hole adapted to allow the push rod to pass through. This arrangement facilitates the assembly of the balance spring assembly.

[0012] In some embodiments, the blade is rotatable between an open position and a closed position, wherein the blade is separated from the fixed contact of the disconnect switch at the open position to enable the disconnect switch to be in an open state, and the blade is connected to the fixed contact at the closed position to enable the disconnect switch to be in a closed state, and the spring is compressed during the rotation of the blade from the open position to the closed position. This arrangement ensures that the spring is compressed throughout the process of the blade rotating from the open position to the closed position.

[0013] In some embodiments, in a direction perpendicular to the push rod located at the closed position, the distance between the first shaft and the second shaft exceeds the diameter of the push rod. Thereby, interference between the push rod and the second shaft can be well avoided.

[0014] In some embodiments, the push rod is radially fixed on the second shaft so that the distance from the second end of the push rod to the second shaft is adjustable. Thus, the compression force of the spring can be adjusted to facilitate the maintenance of the balance spring assembly.

[0015] In some embodiments, the push rod includes a threaded section that engages with a threaded hole in the second shaft. The threaded section can facilitate the adjustment of the push rod relative to the first shaft.

[0016] In some embodiments, the balance spring assembly further includes at least one stopper disposed on the threaded section and adjacent to the second shaft to prevent radial movement of the push rod relative to the second shaft. This arrangement can prevent the push rod from moving radially relative to the first shaft, thereby improving the reliability of the balance spring assembly.

[0017] In a second aspect, a disconnect switch is provided that includes the balance spring assembly according to the first aspect.

[0018] It should be understood that the present invention content is not a key or essential feature for determining the embodiments of the present disclosure, nor is it used to limit the scope of the present disclosure. Through the following description, other features of the present disclosure will become easily understood. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects, features, and advantages of the present disclosure will be better understood through the following exemplary embodiments of the present disclosure described in detail in conjunction with the drawings, wherein in the exemplary embodiments of the present disclosure, the same reference numerals generally represent the same components.

[0020] Figure 1 A perspective view of the contact assembly and the balance spring assembly of a disconnect switch according to an embodiment of the present disclosure is shown, wherein the blade is hidden to show the components disposed therein;

[0021] Figure 2 A side cross-sectional view of the contact assembly and the balance spring assembly of a disconnect switch according to an embodiment of the present disclosure is shown;

[0022] Figure 3 A perspective view of the push rod and the spring according to an embodiment of the present disclosure is shown;

[0023] Figure 4 A side view of the spring according to an embodiment of the present disclosure is shown;

[0024] Figure 5 A perspective view of an insulating block according to an embodiment of the present disclosure is shown;

[0025] Figure 6 A cross-sectional view of a flange according to an embodiment of the present disclosure is shown; and

[0026] Figure 7 Shows a side view of a push rod according to an embodiment of the present disclosure.

[0027] Throughout the drawings, the same or similar reference numerals are used to denote the same or similar elements. Detailed Description

[0028] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that discussing these embodiments is only to enable those skilled in the art to better understand and thus implement the present disclosure, rather than limiting the scope of protection of the present disclosure.

[0029] As used herein, the term "comprising" and its variants should be understood as open-ended terms, meaning "including, but not limited to". The term "based on" should be understood as "at least partially based on". The term "embodiment" should be understood as "at least one embodiment". The term "another embodiment" should be understood as "at least one other embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may be listed below. The definition of a term is consistent throughout the specification unless the context clearly indicates otherwise.

[0030] As described above, in order to reduce the force for driving the blade and the impact on the fixed contact of the disconnecting switch, a balance spring assembly is usually provided between the blade and the base on which the blade is mounted. In traditional solutions, the balance spring assembly usually includes two sets of springs. The springs in the balance spring assembly are compressed during the rotation of the blade from the open position to the closed position. Thus, at least a part of the mass of the blade is transferred and stored in the compressed springs, thereby reducing the impact of the blade on the fixed contact. During the rotation of the blade from the closed position to the open position, the compressed springs provide a restoring force to facilitate the rotation of the blade.

[0031] In traditional solutions, the balance spring assembly is mounted outside the blade. Since disconnecting switches are usually placed in outdoor environments, in order to protect the springs from erosion, multiple components for enclosing the springs are required, such as including: a protective tube and a protective cover. In addition, in order to ensure the compression and decompression of the springs in the protective tube, an auxiliary spring and necessary connecting elements also need to be provided in the protective tube, which requires a complex assembly process for the balance spring assembly.

[0032] In addition, two balance spring assemblies are provided for the blade in each pole. Thus, the blade is arranged between the two balance spring assemblies. This arrangement doubles the already large number of components, resulting in higher costs and complexity.

[0033] In addition, in traditional solutions, the push rod is usually arranged between the knife blade and the base through two pins located at both ends of the push rod. During the rotation of the knife blade, the pins are subjected to a large force. Therefore, the pins are prone to deformation and damage, resulting in reduced reliability and additional maintenance costs.

[0034] In addition, due to the position of the traditional balance spring assembly relative to the knife blade and the base, during the rotation of the knife blade, the spring usually only functions for a limited period of time. For example, during the rotation of the knife blade from the open position to the closed position, before the knife blade rotates beyond the intermediate position, the spring can hardly be compressed. After the knife blade rotates beyond the intermediate position, the force of the knife blade can no longer act on the spring, resulting in the knife blade quickly dropping to the closed position.

[0035] Similarly, during the reverse rotation of the knife blade, that is, from the closed position to the open position, the balance spring assembly also does not work before rotating to the intermediate position, resulting in an increase in the driving force of the drive unit.

[0036] To at least partially address the above and / or other potential problems, embodiments of the present disclosure provide a balance spring assembly 100 for a disconnect switch 200.

[0037] Figure 1 A perspective view of the contact assembly of the disconnect switch 200 and the balance spring assembly 100 is shown. As shown, the disconnect switch 200 includes a contact assembly, which includes a knife blade 201 of the disconnect switch 200 and a fixed contact 203. The knife blade 201 is rotatable about an axis (referred to as the first axis 202 for ease of discussion) to change the operating state of the disconnect switch 200.

[0038] For example, the knife blade 201 is rotatable between an open position and a closed position. As Figure 2 shown, in the open position, the knife blade 201 is separated from the fixed contact 203 to enable the disconnect switch 200 to be in an open state. Thus, the disconnect switch can allow the isolation of devices such as transformers and circuit breakers in the power system. As Figure 1 shown, when the knife blade 201 rotates from the open position to the closed position, the knife blade 201 is connected to the fixed contact 203 to enable the disconnect switch 200 to be in a closed state. Therefore, the circuit allows to be switched on in the closed state.

[0039] As Figure 1 shown, generally, the balance spring assembly 100 according to embodiments of the present disclosure includes a push rod 101 and a spring 102. As Figure 1 and Figure 2 shown, different from the traditional solution, the push rod 101 is partially and coaxially arranged in the knife blade 201 of the disconnect switch 200.

[0040] In addition, as shown in the figure, a spring 102 is also disposed in the knife switch 201 and around the push rod 101. One end of the push rod 101 (referred to as the first end for the convenience of discussion) is fixed to the second shaft 103 so that the push rod 101 can rotate around the second shaft 103. As Figure 1 shown, the spring 102 is held between the second end of the push rod 101 opposite to the first end and the end of the knife switch 201 adjacent to the first shaft 202.

[0041] The first shaft 202 and the second shaft 103 are parallel to each other. Thus, as the knife switch 201 rotates, the spring 102 can be compressed or decompressed. To explain the principle of the present disclosure, a virtual triangle is introduced, as Figure 2 shown. The first side 110 of the triangle is from the first shaft 202 to the second shaft 103, the second side 111 is from the second shaft 103 to the end of the knife switch 201 adjacent to the first shaft 202, and the third side 112 is from the first shaft 202 to the end of the knife switch 201 adjacent to the first shaft 202.

[0042] It can be understood that the lengths of the first side 110 and the third side 112 are constant. When the knife switch 201 is in the open position as Figure 2 shown, the angle between the first side and the third side 110, 112 is an acute angle, resulting in a relatively small length of the second side 111. When the knife switch 201 rotates from the open position to the closed position as Figure 1 shown, the angle between the first side and the third side 110, 112 becomes an obtuse angle, resulting in a relatively large length of the second side 111.

[0043] The length of the second side 111 is equal to the length of the push rod 101 extending out of the knife switch 201. That is to say, as the knife switch 201 rotates from the open position to the closed position, the length of the push rod 101 extending out of the knife switch 201 becomes longer. Thus, when the knife switch 201 rotates from the open position to the closed position, the length of the push rod 101 in the knife switch becomes shorter, causing the spring 102 disposed in the knife switch 201 to be compressed. When the knife switch 201 rotates from the open position to the closed position, the compressed spring 102 can absorb the potential energy released due to the weight of the knife switch 201. Therefore, the impact on the fixed contact 203 can be significantly reduced.

[0044] Specifically, it should be understood that during the entire process of the knife switch 201 rotating from the open position to the closed position, the length of the push rod 101 in the knife switch 201 is continuously decreasing. That is to say, when the knife switch 201 rotates from the open position to the closed position, the spring 102 is continuously compressed to absorb potential energy. Thus, the speed of the knife switch 201 can be effectively controlled to reduce the impact on the fixed contact 203.

[0045] Similarly, during the rotation of the knife blade 201 from the closed position to the open position, the fully compressed spring 102 continuously and gradually returns to provide an auxiliary force to facilitate the rotation of the knife blade 201. Accordingly, the driving force for driving the knife blade 201 is reduced.

[0046] In some embodiments, when the knife blade 201 is in the open position, the spring 102 can be in a pre-compressed state, as Figure 2 shown. This setting can improve the robustness of the balance spring assembly 100.

[0047] As can be seen from the above, by disposing the balance spring assembly 100 at least partially in the knife blade 201 of the disconnect switch 200, only one set of springs is sufficient to reduce the force for driving the knife blade 201 and the impact on the fixed contact 203. In addition, no additional components such as protection tubes, auxiliary springs, and some connecting elements are required. Thus, the manufacturing and assembly costs of the disconnect switch 200 can be significantly reduced. In addition, with this setting, when the knife blade 201 rotates between the open position and the closed position, the spring 102 can always work.

[0048] In some embodiments, the balance spring assembly 100 includes a retaining block 107 disposed at the second end of the push rod 101. Thus, one end of the spring 102 can be held on the retaining block 107. In addition, in some embodiments, the balance spring assembly 100 further includes a flange 105 disposed at the end of the knife blade 201 adjacent to the first shaft 202. The other end of the spring 102 can be held on the flange 105.

[0049] From Figure 3 and Figure 4 it can be seen that the end face of the spring 102 is in a planar shape, and this end face is in contact with the surfaces of the flange 105 and the retaining block 107 respectively. Thus, the spring 102 can be held between the flange 105 and the retaining block 107, as Figure 5 and Figure 6 shown. Therefore, compared with traditional solutions, the compression force of the spring 102 is applied on a surface rather than a point, thereby reducing the risk of damage to the stressed components. Thus, the reliability of the balance spring assembly 100 can be improved.

[0050] In some embodiments, the retaining block 107 can be fixed to the second end of the push rod 101 by screws or any other suitable fasteners. For example, in some alternative embodiments, the retaining block 107 can also be fixed to the push rod 101 by welding, snap connection, or the like.

[0051] In addition, the insulating ring 104 can be coaxially disposed around the retaining block 107. For example, as Figure 5As shown, the insulating ring 104 can be disposed in an annular groove formed on the outer surface of the holding block 107. Thus, the insulating ring 104 is disposed between the inner surface of the knife blade 201 and the outer surface of the holding block 107. On the one hand, the insulating ring 104 can provide electrical insulation between the knife blade 201 and the push rod 101. On the other hand, the insulating ring 104 can eliminate the wobbling of the holding block 107 caused by the gap between the holding block 107 and the knife blade, thereby making the sliding of the holding block 107 in the knife blade 201 smoother.

[0052] To facilitate the passage of the push rod 101 through the flange 105, in some embodiments, a through hole 1051 can be provided on the flange 105. This setting facilitates the assembly of the balance spring assembly 100.

[0053] Referring Figure 1 and Figure 2 , in some embodiments, to avoid interference between the push rod 101 and the first shaft 202, in a direction perpendicular to the push rod 101 in the closed position, the distance D between the first shaft 202 and the second shaft 103 can exceed the diameter of the push rod 101. "Exceed" means that the distance D is equal to or greater than the diameter of the push rod 101. Thus, the push rod 101 can be rotated to the closed position without interfering with the first shaft 202.

[0054] In some embodiments, the push rod 101 can be radially fixed to the second shaft 103 so that the distance from the second end of the push rod 101 to the second shaft 103 can be adjusted. For example, the user can adjust the distance from the second end of the push rod 101 to the second shaft 103 to adjust the pre-compression force of the spring 102. In addition, this setting also facilitates the replacement of springs of different lengths. Thus, it is beneficial to the maintenance of the balance spring assembly 100.

[0055] To allow the distance from the second end of the push rod 101 to the second shaft 103 to be adjustable, in some embodiments, the push rod 101 includes a threaded section 1011, as Figure 7 shown. In addition, a threaded hole can be provided radially on the second shaft 103. Thus, the threaded section 1011 can engage with the threaded hole to allow adjustment of the distance from the second end of the push rod 101 to the second shaft 103.

[0056] In some embodiments, to prevent unnecessary movement of the push rod 101 relative to the second shaft 103, at least one stop 106 is provided on the threaded section 1011. As Figure 1 shown, in some embodiments, two stops 106 are provided adjacent to the second shaft 103. Thus, when the distance from the second end of the push rod 101 to the second shaft 103 is well adjusted, the movement of the push rod 101 relative to the second shaft 103 is prevented.

[0057] Embodiments of the present disclosure further provide a disconnect switch including the balance spring assembly 100 as described above. By providing the balance spring assembly 100, the reliability of the disconnect switch can be improved while reducing the cost of the disconnect switch.

[0058] It should be understood that the above specific embodiments of the present disclosure are only for demonstrating or explaining the principles of the present disclosure, rather than for limiting the scope of the present disclosure. Therefore, any modifications, equivalent alternatives, improvements, etc. should be included within the protection scope of the present disclosure without departing from the essence and scope of the present disclosure. At the same time, the appended claims of the present disclosure are intended to cover all changes and modifications that fall within the scope and bounds of the claims or are equivalent to such scope or bounds.

Claims

1. A balance spring assembly for a disconnector, comprising: A push rod (101) partially and coaxially disposed in a blade (201) of the disconnector (200), the blade (201) being rotatable about a first axis (202) to change an operating state of the disconnector (200), a first end of the push rod (101) being fixed to a second axis (103) to enable the push rod (101) to rotate about the second axis (103); and A spring (102) disposed in the blade (201) and surrounding the push rod (101), the spring (102) being held between a second end of the push rod (101) and an end of the blade (201) adjacent to the first axis (202), Wherein the second axis (103) is disposed parallel to the first axis (202) to enable the push rod (101) to axially move in the blade (201) as the blade (201) rotates, thereby compressing or decompressing the spring (102).

2. The balance spring assembly according to claim 1, further comprising a holding block (107) disposed at the second end of the push rod (101) to hold one end of the spring (102).

3. The balance spring assembly according to claim 2, further comprising: An insulating ring (104) coaxially surrounding the holding block (107) to provide insulation and guidance between the holding block (107) and the blade (201).

4. The balance spring assembly according to claim 2, further comprising: A flange (105) disposed at the end of the blade (201) to hold one end of the spring (102).

5. The balance spring assembly according to claim 4, wherein the flange (105) includes a through hole (1051) adapted to allow the push rod (101) to pass through.

6. The balance spring assembly according to claim 1, wherein, The blade (201) is rotatable between an open position and a closed position, wherein the blade (201) is separated from a fixed contact (203) of the disconnector (200) in the open position to enable the disconnector (200) to be in an open state, while the blade (201) is connected to the fixed contact (203) in the closed position to enable the disconnector (200) to be in a closed state, and Wherein the spring (102) is compressed during rotation of the blade (201) from the open position to the closed position.

7. The balance spring assembly according to claim 6, wherein, In a direction perpendicular to the push rod (101) in the closed position, the distance (D) between the first axis (202) and the second axis (103) exceeds the diameter of the push rod (101).

8. The balance spring assembly according to claim 1, wherein, The push rod (101) is radially fixed to the second axis (103) to enable the distance from the second end of the push rod (101) to the second axis (103) to be adjustable.

9. The balance spring assembly according to claim 8, wherein, The push rod (101) includes a threaded section (1011) that engages with the threaded hole of the second shaft (103).

10. The balance spring assembly according to claim 9, further comprising: At least one stopper (106) disposed on the threaded section (1011) and adjacent to the second shaft (103) to prevent radial movement of the push rod (101) relative to the second shaft (103).

11. A disconnect switch comprising the balance spring assembly according to any one of claims 1-10.

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