A molded case circuit breaker guard

Abstract

The application relates to the technical field of circuit breakers, and particularly discloses a plastic-clad circuit breaker protective cover which comprises a front protective plate, an upper protective plate and two side protective plates, the front protective plate, the upper protective plate and the side protective plates are vertically distributed in pairs, the side protective plates are arranged in an inverted L shape, positioning pin columns are arranged on the sides of the horizontal sections of the two side protective plates which are opposite to each other, the positioning pin columns are in sliding connection with the circuit breaker, a limiting pin column is arranged on the outer wall of the horizontal section of one of the side protective plates, a limiting groove is arranged on the outer wall of the horizontal section of the side protective plate which is away from the limiting pin column, and the limiting pin column is matched with the limiting groove. The butt joint of the plurality of protective cover bodies separates a plurality of wire-coupling cavities of the circuit breaker, the opening of the circuit breaker protective cover of the already-powered equipment in the electric cabinet is avoided, the efficiency of leading the wires of the copper nose or the copper-pipe cold-shrink tube insulating material is improved, the installation of the to-be-powered equipment is facilitated, and the safety is improved.

Description

Technical Field

[0001] This invention relates to the field of circuit breaker technology, and more specifically to a protective cover for a molded case circuit breaker. Background Technology

[0002] A circuit breaker is a current switching device used to distribute electrical energy and provide real-time protection for power lines and motors. It can carry, close, and interrupt the current in a normal circuit according to the normal, overload, short circuit, and undervoltage states of the circuit, thereby ensuring safe production. Molded case circuit breakers, as a type of circuit breaker, use plastic insulators as the outer shell of the device. With the introduction of multi-opening molded case circuit breakers, this type of circuit breaker is now widely used in microelectronics factories. Low-voltage equipment requires power supply and wiring verification. Electrical cabinets often contain both energized and waiting-to-be-energized equipment at the same time. Careless operation can easily lead to power outages and electric shock accidents.

[0003] When existing multi-phase molded case circuit breakers are used in factory electrical cabinets, the installation frequency is high because both energized and pending equipment are often present in the cabinets simultaneously. Furthermore, multiple circuit breaker terminals typically share a single protective cover, requiring the cover to be removed, and the connection points of the copper lugs or copper busbars with heat-shrink tubing and other insulating materials to be led out of the cover before re-fixing it. This process is time-consuming and labor-intensive. During installation, the complete exposure of both energized and pending terminals increases the risk of power outages and electric shocks, making the safety insufficient. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, this invention provides a protective cover for molded case circuit breakers, which can overcome these issues.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A protective cover for a molded case circuit breaker includes an integrally molded front protective plate, an upper protective plate, and two side protective plates. The front, upper, and side protective plates are arranged vertically in pairs. The side protective plates are arranged in an inverted L-shape. Positioning pins are fixedly installed on opposite sides of the horizontal sections of the two side protective plates. The positioning pins are slidably connected to the circuit breaker. A limit pin is provided on the outer wall of the horizontal section of one side protective plate, and a limit groove is provided on the outer wall of the horizontal section of the side protective plate away from the limit pin. The limit pin aligns with the limit groove. The front and upper protective plates are equipped with heat dissipation structures. The front protective plate is equipped with a clamping component for leading out and fixing the connection part of the copper lug or copper busbar sleeve cold and heat shrink tubing insulation material. The integrally formed front protective plate, upper protective plate and side protective plate form the main body of the insulating circuit breaker protective cover. With the help of two positioning pins, the main body of the protective cover is slidably connected to the circuit breaker. The connection of multiple protective cover bodies separates multiple line-connecting chambers of the circuit breaker, avoiding the opening of the circuit breaker protective cover of the energized equipment in the electrical cabinet, and improving the safety of use.

[0007] Furthermore, the fastening assembly includes a support frame, an open opening at the bottom of the front protective plate, and the support frame fixedly installed on the wall of the open opening of the front protective plate. The bottom horizontal section of the support frame has a mating interface matching the circuit breaker. A transparent plate is fixedly installed between the two vertical sections of the support frame, with its top end fixedly connected to the top wall of the support frame. A limiting plate is slidably installed between the two vertical sections of the support frame. A comb plate is fixedly installed between the two vertical sections of the support frame, with its bottom end fixedly connected to the bottom wall of the support frame. The front and rear surfaces of the limiting plate are respectively fitted and slidably disposed with respect to the transparent plate and the comb plate. The comb plate... The toothed groove has a U-shaped cross-section. The bottom end of the limiting plate has a slot. Two levers are provided on the side of the limiting plate near the transparent plate. The upper protective plate has a limiting structure for fixing the protective cover and the circuit breaker. Initially, the lever is located in the notch. After the connecting part of the copper lug or copper busbar with heat shrink tubing and other insulating materials is led out from between the limiting plate and the comb plate and locked into the comb groove, the lever is held and the limiting plate is pushed down. The slot cooperates with the comb groove to fix the connecting part. The gap between the top of the comb plate and the bottom of the transparent plate is used to lead out the connecting part of the irregular copper lug or irregular copper busbar, which improves the lead-in efficiency of the copper lug or copper busbar with heat shrink tubing and other insulating materials.

[0008] Preferably, the heat dissipation structure includes a dust filter cover. The side walls of the front protective plate and the upper protective plate are provided with a plurality of heat dissipation holes arranged in an array. The cross-section of the heat dissipation holes is set in a rounded rectangle. The dust filter cover is fixedly installed between the plurality of heat dissipation holes. The heat dissipation holes, together with the dust filter cover, not only have the function of ventilation and heat dissipation, but also have the function of dust prevention, reducing the possibility of static electricity generation in the circuit breaker.

[0009] Preferably, the dust filter cover is made of metal, the dust filter part of the dust filter cover is located inside the heat dissipation holes, and the end face of the dust filter part of the dust filter cover is provided with an insulating coating, so the dust filter cover has insulation properties.

[0010] Preferably, the limiting plate has protrusions on both the left and right sides, and the inner walls of the supporting frame have grooves on both the left and right sides. The protrusions of the limiting plate match the grooves of the supporting frame, and the grooves of the supporting frame are provided with a damping coating. The damping coating increases the coefficient of friction between the limiting plate and the supporting frame, preventing free sliding.

[0011] Preferably, the slot and the curved part of the comb tooth plate have the same curvature. The slot, in conjunction with the comb tooth plate, is used to lead out the connection part of the copper lug or copper busbar with heat shrink tubing or other insulating materials. The transparent plate and the limiting plate have the same length in the vertical direction and are greater than half the length of the support frame. The length of the comb tooth plate in the vertical direction is less than one-quarter of the length of the support frame. The distance between the top end of the comb tooth plate and the bottom end of the transparent plate is used to accommodate irregularly shaped copper lugs or copper busbars. The distance between the top end of the comb tooth plate and the bottom end of the transparent plate is used to lead out the connection part of the irregularly shaped copper lug or copper busbar.

[0012] Preferably, the bottom end of the transparent plate is provided with two notches, and the lever is matched with the notches.

[0013] Preferably, the limiting structure includes a support column, which is rotatably mounted through and on the top of the upper protective plate. A rotating block is fixedly mounted on the top of the support column. The sidewall of the support column has multiple arrayed protrusions. The bottom of the upper protective plate has multiple limiting channels, and the protrusions match the limiting channels of the upper protective plate. A limiting block is fixedly mounted on the bottom of the support column, and the limiting block and rotating block are spatially perpendicular. The circuit breaker base has limiting holes that match the limiting blocks. The cross-section of the upper limiting hole in the circuit breaker is convex ("U") shaped. The hole is divided into a limiting section and a rotating section. The top of the upper protective plate is provided with an elastic support structure for resetting the support column. After holding the rotating block and pressing it down a certain distance, the protrusion slides from the limiting channel of the upper protective plate. The limiting block slides from the limiting section of the limiting hole to the rotating section or is not in the limiting hole. Then, rotate the rotating block clockwise by 90 degrees and release it. The limiting block rotates synchronously to disengage from the limiting hole or enter the rotating section of the limiting hole, switching the limiting state of the limiting structure. The spring drives the ring plate to slide in the support cylinder, driving the support column and the rotating block to reset, which facilitates the installation or disassembly of the protective cover body.

[0014] Preferably, the elastic support structure includes a support cylinder, which is fixedly installed on the top of the upper protective plate. A ring plate is fixedly sleeved on the side wall of the support column. The ring plate is slidably installed inside the support cylinder. A spring is fixedly installed at the bottom end of the ring plate. The bottom end of the spring is fixedly connected to the top of the upper protective plate.

[0015] The beneficial effects of this invention are as follows:

[0016] 1. By setting a front protective plate, an upper protective plate, and a side protective plate, the integrated front protective plate, upper protective plate, and side protective plate form the main body of the insulating circuit breaker protective cover. With the help of two positioning pins, the main body of the protective cover is slidably connected to the circuit breaker. The connection of multiple protective cover bodies separates multiple line-connecting chambers of the circuit breaker, avoiding the opening of the circuit breaker protective cover of the already energized equipment in the electrical cabinet, facilitating the installation of the equipment to be energized, and improving safety.

[0017] 2. By setting up a locking component, the initial position is within the notch. After the connecting part of the copper lug or copper busbar with heat shrink tubing and other insulating materials is led out from between the limiting plate and the comb plate and locked into the comb groove, the limiting plate is pushed down by holding the lever. The locking groove cooperates with the comb groove to fix the connecting part. The gap between the top of the comb plate and the bottom of the transparent plate is used to lead out the connecting part of the irregular copper lug or irregular copper busbar, which improves the lead-out efficiency of the copper lug or copper busbar with heat shrink tubing and other insulating materials.

[0018] 3. By setting up a heat dissipation structure, the heat dissipation holes are combined with a dust filter cover, which not only has the function of ventilation and heat dissipation, but also has the function of dust prevention, reducing the possibility of static electricity generation inside the circuit breaker.

[0019] 4. By setting a limiting structure, after holding the rotating block and pressing it down a certain distance, the convex strip slides from the limiting channel of the upper protective plate. The limiting block slides from the limiting section of the limiting hole to the rotating section or is not in the limiting hole. Then, rotate the rotating block 90 degrees clockwise and release it. The limiting block rotates synchronously and leaves the limiting hole or enters the rotating section of the limiting hole, switching the limiting state of the limiting structure. The spring drives the ring plate to slide in the support cylinder, driving the support column and the rotating block to reset, which improves the efficiency of installing and disassembling the protective cover. Attached Figure Description

[0020] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 This is a structural diagram of the dust filter screen in this invention;

[0023] Figure 3 This is a diagram showing the installation structure of the comb plate in this invention;

[0024] Figure 4 This is an exploded view of the locking component in this invention;

[0025] Figure 5 This is a diagram showing the installation structure of the limiting block in this invention;

[0026] Figure 6 This is a diagram showing the installation structure of the convex strip in this invention.

[0027] Explanation of key component symbols:

[0028] In the diagram: 1. Front protective plate; 2. Upper protective plate; 3. Side protective plate; 4. Positioning pin; 5. Limiting pin; 6. Limiting groove; 7. Heat dissipation hole; 8. Dust filter cover; 9. Support frame; 10. Transparent plate; 11. Limiting plate; 12. Comb plate; 13. Slot; 14. Pulling block; 15. Notch; 16. Support column; 17. Rotating block; 18. Protrusion; 19. Limiting block; 20. Support cylinder; 21. Ring plate; 22. Spring. Detailed Implementation

[0029] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the specific implementation methods, structures, features, and effects of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and preferred embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] In the description of this application, it should be understood that the orientation or positional relationship indicated by terms such as "inner" and "outer" are based on the orientation or position shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, a specific orientation structure and operation, and therefore should not be construed as a limitation of this application.

[0031] Reference Figure 1 and Figure 3This invention discloses a protective cover for a molded case circuit breaker, comprising an integrally formed front protective plate 1, an upper protective plate 2, and two side protective plates 3. The front protective plate 1, upper protective plate 2, and side protective plates 3 are arranged vertically in pairs to form the main body of the circuit breaker protective cover. The side protective plates 3 are arranged in an inverted L-shape. Positioning pins 4 are fixedly installed on the opposite side of the horizontal section of each of the two side protective plates 3. The positioning pins 4 are slidably connected to the circuit breaker. A limiting pin 5 is provided on the outer wall of the horizontal section of one of the side protective plates 3, and a limiting groove 6 is provided on the outer wall of the horizontal section of the side protective plate 3 away from the limiting pin 5. The limiting pin 5 and the limiting groove 6 are matched to prevent the opening of the circuit breaker protective cover of the energized equipment in the electrical cabinet, facilitate the docking of multiple protective covers, and facilitate the installation of the equipment to be energized.

[0032] Reference Figures 1-3 Both the front protective plate 1 and the upper protective plate 2 are equipped with heat dissipation structures, including a dust filter cover 8. Multiple heat dissipation holes 7 are arranged in an array on the side walls of both the front protective plate 1 and the upper protective plate 2. The cross-section of the heat dissipation holes 7 is set in a rounded rectangle and has a heat dissipation function. The dust filter cover 8 is fixedly installed between the multiple heat dissipation holes 7. The dust filter cover 8 is made of metal. The dust filter part of the dust filter cover 8 is located inside the heat dissipation holes 7. The end face of the dust filter part of the dust filter cover 8 is provided with an insulating coating, which has a dustproof function and reduces the possibility of static electricity generation in the circuit breaker.

[0033] Reference Figure 1 and Figures 3-4The front protective plate 1 is equipped with a locking assembly for leading out and fixing the connection part of the copper lug or copper busbar sleeve cold and heat shrink tubing insulation material. The locking assembly includes a support frame 9, with an opening at the bottom end of the front protective plate 1. The support frame 9 is fixedly installed on the wall of the opening of the front protective plate 1, providing support. A mating interface matching the circuit breaker is provided on the bottom horizontal section of the support frame 9. A transparent plate 10 is fixedly installed between the two vertical sections of the support frame 9. The top of the transparent plate 10 is fixedly connected to the top wall of the support frame 9, providing support and light transmission. A limit plate 11 is slidably installed between the two vertical sections of the support frame 9. The limit plate 11 has protrusions on both the left and right sides. The inner walls of both the left and right sides of the support frame 9 have sliding grooves. The protrusions of the limit plate 11 match the sliding grooves of the support frame 9. A damping coating is provided in the sliding grooves of the support frame 9. A comb plate 12 is fixedly installed between the two vertical sections of the support frame 9. The bottom end of the comb plate 12 is fixedly connected to the bottom wall of the support frame 9, providing support. The cable management structure is such that the front and rear sides of the limiting plate 11 are respectively fitted and slidably disposed with the transparent plate 10 and the comb plate 12. The comb groove of the comb plate 12 has a U-shaped cross-section. A slot 13 is provided at the bottom end of the limiting plate 11. The slot 13 and the curved part of the comb groove of the comb plate 12 have the same curvature. The slot 13 cooperates with the comb plate 12 to lead out the connection part of the copper lug or copper busbar sleeve cold and heat shrink tubing and other insulating materials. The transparent plate 10 and the limiting plate 11 have the same length in the vertical direction and are large. The length of the comb plate 12 in the vertical direction is less than one-quarter of the length of the support frame 9, which is half the length of the support frame 9. The distance between the top of the comb plate 12 and the bottom of the transparent plate 10 is used to accommodate irregularly shaped copper noses or irregularly shaped copper busbars. Two levers 14 are provided on the side of the limiting plate 11 near the transparent plate 10, and two notches 15 are provided at the bottom of the transparent plate 10. The levers 14 match the notches 15. The levers 14 are used for electrical adjustment of the position of the limiting plate 11 within the support frame 9.

[0034] Reference Figures 1-2 and Figures 5-6, a limiting structure for fixing the protective cover and the circuit breaker is provided on the upper protective plate 2. The limiting structure includes a support column 16, which is penetrated and rotatably installed at the top end of the upper protective plate 2 and has a supporting function. A rotating block 17 is fixedly installed at the top end of the support column 16 for an electrician to hold and rotate. A plurality of protruding strips 18 are arranged in an array on the side wall of the support column 16. A plurality of limiting channels are provided at the bottom end of the upper protective plate 2. The protruding strips 18 are matched with the limiting channels of the upper protective plate 2. A limiting block 19 is fixedly installed at the bottom end of the support column 16. The limiting block 19 and the rotating block 17 are vertically distributed in space. A limiting hole matched with the limiting block 19 is provided on the circuit breaker base. The cross-section of the limiting hole on the circuit breaker is arranged in a "convex" shape. The limiting hole is divided into a limiting section and a rotating section. When the protruding strip 18 is located in the limiting channel of the upper protective plate 2 and the limiting block 19 is located in the limiting section of the limiting hole, the limiting structure is in a limiting state. An elastic support structure for resetting the support column 16 is provided at the top end of the upper protective plate 2. The elastic support structure includes a support cylinder 20, which is fixedly installed at the top end of the upper protective plate 2 and has a supporting function. A ring plate 21 is fixedly sleeved on the side wall of the support column 16. The ring plate 21 is slidably installed in the support cylinder 20 and has a supporting function. A spring 22 is fixedly installed at the bottom end of the ring plate 21. The bottom end of the spring 22 is fixedly connected to the top end of the upper protective plate 2. The spring 22 is in a compressed state and has an elastic supporting function. After holding the rotating block 17 and pressing it downward for a certain distance, the protruding strip 18 slides out of the limiting channel of the upper protective plate २, and the limiting block 19 slides from the limiting section of the limiting hole to the rotating section or is not in the limiting hole. Then, rotate the rotating block 17 clockwise by 90 degrees and release it. The limiting block 19 rotates synchronously to disengage from the limiting hole or enters the rotating section of the limiting hole, switching the limiting state of the limiting structure. The spring 22 drives the ring plate 21 to slide in the support cylinder 20, driving the support column 16 and the rotating block 17 to reset.

[0035] It should be noted that there seems to be a small error in the original text where "२" appears instead of "2" in one place, and this has been corrected in the translation.The working principle and usage process of this invention: The integrated front protective plate 1, upper protective plate 2, and side protective plate 3 form the main body of the insulating circuit breaker protective cover. Two positioning pins 4 are used to slide and connect the main body of the protective cover to the circuit breaker. The connection of multiple protective covers avoids opening the circuit breaker protective covers of already energized equipment in the electrical cabinet, facilitating the installation of equipment to be energized and improving safety. The lever 14 is initially positioned within the notch 15. After the connecting part of the copper lug or copper busbar sleeve with heat shrink tubing and other insulating materials is led out from between the limiting plate 11 and the comb tooth plate 12 and inserted into the comb tooth groove, the lever is held to push the limiting plate 11 downwards. The slot 13 engages with the comb teeth. The groove fixes the connecting part. The gap between the top of the comb plate 12 and the bottom of the transparent plate 10 is used for the connecting part of the irregular copper nose or irregular copper busbar. After holding the rotating block 17 and pressing it down a certain distance, the protrusion 18 slides from the limiting channel of the upper protective plate 2. The limiting block 19 slides from the limiting section of the limiting hole to the rotating section or is not in the limiting hole. Then, rotate the rotating block 17 clockwise by 90 degrees and release it. The limiting block 19 rotates synchronously to get out of the limiting hole or enter the rotating section of the limiting hole, switching the limiting state of the limiting structure. The spring 22 drives the ring plate 21 to slide in the support cylinder 20, driving the support column 16 and the rotating block 17 to reset.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A protective cover for a molded case circuit breaker, comprising an integrally formed front protective plate, an upper protective plate, and two side protective plates, characterized in that: The front protective plate, upper protective plate, and side protective plates are arranged vertically in pairs. The side protective plates are arranged in an inverted L-shape. Positioning pins are fixedly installed on the opposite side of the horizontal sections of the two side protective plates. The positioning pins are slidably connected to the circuit breaker. A limiting pin is provided on the outer wall of the horizontal section of one of the side protective plates. A limiting groove is provided on the outer wall of the horizontal section of the side protective plate away from the limiting pin. The limiting pin matches the limiting groove. Both the front protective plate and the upper protective plate are provided with heat dissipation structures. The front protective plate is provided with a clamping component for leading out and fixing the connection part of the copper lug or copper busbar sleeve cold and heat shrink tubing insulation material. The fastening assembly includes a support frame, an open opening at the bottom of the front protective plate, the support frame being fixedly installed on the wall of the open opening of the front protective plate, a mating interface matching the circuit breaker being provided on the bottom horizontal section of the support frame, a transparent plate being fixedly installed between the two vertical sections of the support frame, the top of the transparent plate being fixedly connected to the top wall of the support frame, a limiting plate being slidably installed between the two vertical sections of the support frame, a comb plate being fixedly installed between the two vertical sections of the support frame, the bottom end of the comb plate being fixedly connected to the bottom wall of the support frame, the front and rear sides of the limiting plate being slidably fitted with the transparent plate and the comb plate respectively, the comb groove of the comb plate being U-shaped, a slot being provided at the bottom of the limiting plate, two levers being provided on the side of the limiting plate near the transparent plate, and a limiting structure for fixing the protective cover and the circuit breaker being provided on the upper protective plate; The slot and the comb tooth plate have the same curvature. The slot and the comb tooth plate are used to lead out the connection part of the copper lug or copper busbar with heat shrink tubing and other insulating materials. The transparent plate and the limiting plate have the same length in the vertical direction and are greater than half the length of the support frame. The length of the comb tooth plate in the vertical direction is less than one-quarter of the length of the support frame. The distance between the top end of the comb tooth plate and the bottom end of the transparent plate is used to accommodate irregularly shaped copper lugs or irregularly shaped copper busbars. The limiting structure includes a support column, which is rotatably mounted through and on the top of the upper protective plate. A rotating block is fixedly installed on the top of the support column. The side wall of the support column is provided with multiple arrayed protrusions. The bottom end of the upper protective plate is provided with multiple limiting channels. The protrusions match the limiting channels of the upper protective plate. A limiting block is fixedly installed on the bottom end of the support column. The limiting block and the rotating block are spatially perpendicular. The circuit breaker base is provided with a limiting hole that matches the limiting block. The cross-section of the upper limiting hole of the circuit breaker is convex. The limiting hole is divided into a limiting section and a rotating section. The top of the upper protective plate is provided with an elastic support structure for resetting the support column.

2. The protective cover for a molded case circuit breaker according to claim 1, characterized in that: The heat dissipation structure includes a dust filter cover. The side walls of the front protective plate and the upper protective plate are provided with a plurality of heat dissipation holes arranged in an array. The cross-section of the heat dissipation holes is arranged in a rounded rectangle. The dust filter cover is fixedly installed between the plurality of heat dissipation holes.

3. A protective cover for a molded case circuit breaker according to claim 2, characterized in that: The dust filter cover is made of metal, and the dust filter part of the dust filter cover is located inside the heat dissipation holes. The end face of the dust filter part of the dust filter cover is provided with an insulating coating.

4. A protective cover for a molded case circuit breaker according to claim 1, characterized in that: The limiting plate has protrusions on both the left and right sides, and the inner walls of the supporting frame have sliding grooves on both the left and right sides. The protrusions of the limiting plate match the sliding grooves of the supporting frame, and the sliding grooves of the supporting frame are provided with a damping coating.

5. A protective cover for a molded case circuit breaker according to claim 1, characterized in that: The bottom of the transparent plate has two notches, and the lever matches the notches.

6. A protective cover for a molded case circuit breaker according to claim 1, characterized in that: The elastic support structure includes a support cylinder, which is fixedly installed on the top of the upper protective plate. A ring plate is fixedly sleeved on the side wall of the support column. The ring plate is slidably installed inside the support cylinder. A spring is fixedly installed at the bottom end of the ring plate. The bottom end of the spring is fixedly connected to the top end of the upper protective plate.

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