CN118775558A - A three-eccentric butterfly valve capable of bidirectional sealing - Google Patents

Abstract

The invention discloses a three-eccentric butterfly valve capable of being sealed in two directions, which belongs to the technical field of three-eccentric butterfly valves and comprises a butterfly valve body, a sliding pin shaft and a linkage assembly, wherein a water contact disc in the linkage assembly is arranged to face a water flow direction, the water contact disc is enabled to move towards a driving connecting shaft through water pressure, and two sides of the water contact disc are matched with two sides of the linkage assembly to enable two sides of the sliding pin shaft to move outwards in the sliding boss, so that the end parts of the two sides of the sliding pin shaft are enabled to contact the inner wall of the butterfly valve body, a first reset spring is stressed and contracted, a sealing disc is enabled to be more stable in the butterfly valve body through friction force between the end parts of the sliding pin shaft and the inner wall of the butterfly valve body, the sealing disc can still keep sealing on water after the driving connecting shaft loosens, the contact area of a concave surface in the water contact disc is larger, and the influence of the water contact disc on flow can be reduced through each water penetration hole when the sealing disc is opened through the arrangement of a plurality of water penetration holes.

Description

A three-eccentric butterfly valve capable of bidirectional sealing

Technical Field

The invention belongs to the technical field of triple-eccentric butterfly valves, and in particular relates to a triple-eccentric butterfly valve capable of bidirectional sealing.

Background Art

The butterfly valve, also known as the flap valve, is a simple regulating valve. The opening and closing part of the butterfly valve is a disc-shaped butterfly plate. By rotating the butterfly plate around the corresponding axis in the valve body, the purpose of opening, closing or regulating the flow of the medium is achieved. The butterfly valve is not only simple in structure, small in size, light in weight, economical in material consumption, small in installation size, small in driving torque, easy and quick to operate, but also has good flow regulation function and closing and sealing characteristics at the same time. It is one of the fastest growing valve varieties in the past decade. Butterfly valves are divided into center-sealed butterfly valves, single-eccentric sealed butterfly valves, double-eccentric sealed butterfly valves and triple-eccentric sealed butterfly valves according to their structural forms.

Among them, the triple eccentric butterfly valve has three eccentric structures. The first eccentricity refers to the eccentric dimension between the valve stem axis and the radial sealing surface of the butterfly plate, that is, the axial eccentricity. The second eccentricity refers to the eccentric dimension between the valve stem axis and the channel axis of the valve body, that is, the radial eccentricity. The third eccentricity refers to the formation of an oblique cone angle between the valve seat seal and the channel axis of the valve body, that is, the angular eccentricity. Due to the existence of the angular eccentricity, the butterfly plate is usually a right-angled oblique circular frustum, and its outer peripheral surface is an oblique circular frustum curved surface.

For example, Chinese invention patent CN115264087A discloses a three-eccentric butterfly valve capable of bidirectional sealing, comprising a valve body, in which a valve shaft and a butterfly plate are arranged, the valve shaft is eccentrically arranged on the bottom surface of the butterfly plate, the projection of the axis of the valve shaft on the butterfly plate divides the butterfly plate into a first plate and a second plate, the sealing assembly comprises a fixed valve seat and a movable valve seat, the area of the first plate on the side of the butterfly plate facing away from the valve shaft is larger than the area of the second plate, the area of the end face of the movable valve seat on the side facing away from the valve shaft is larger than the difference between the areas of the first plate and the second plate on the side of the butterfly plate facing away from the valve shaft, when in use, the movable valve seat can push the butterfly plate that has been deflected by a small angle to reset the butterfly plate, and then the butterfly plate is kept sealed with the movable sealing ring on the fixed valve seat and with the inner wall surface of the movable valve seat, so that liquid leakage is not likely to occur.

Although the above-mentioned prior art can achieve better sealing performance, if the valve shaft and the disc plate become loose, the disc plate will rotate under the impact of the water pressure inside the pipeline, resulting in a gap between the disc plate and the valve body, thereby causing water in the water pipe to leak out.

Summary of the invention

The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

In order to solve the problem that the valve shaft and the disc plate become loose as mentioned in the background technology, the disc plate rotates under the impact of the water pressure inside the pipeline, resulting in a gap between the disc plate and the valve body, thereby causing water in the water pipe to leak out, the present invention adopts the following technical solution.

A three-eccentric butterfly valve capable of bidirectional sealing comprises a butterfly valve body, the outer walls of both sides of the butterfly valve body are fixedly connected with connecting flanges, the outer wall of the butterfly valve body near the upper end is equipped with a transmission housing, a driving connecting shaft is rotatably connected to the inner center of the butterfly valve body, the upper end of the driving connecting shaft passes through the butterfly valve body and is detachably connected to the transmission housing, an adjusting hand wheel is rotatably connected to the outer wall of the transmission housing, a sealing disc is detachably connected to the outer wall of the driving connecting shaft, and is characterized in that sliding bosses are fixedly connected to both sides of the outer wall of the sealing disc near the driving connecting shaft, sliding pins are slidably connected to the sliding bosses on both sides, linkage components are installed on the sliding pins on both sides, and the linkage components enable the sliding pins on both sides to move outwards at the same time.

Preferably, a water-dividing tip is fixedly connected to the outer wall of the sealing disc away from the water-contacting disc.

Preferably, mounting cylinder sleeves are embedded on both sides of the inner wall of the butterfly valve body, the first piston blocks are slidably connected inside the mounting cylinder sleeves on both sides, and sealing bosses are fixedly connected to the outer walls of the opposite surfaces of the first piston blocks on both sides, and the sealing bosses on both sides pass through the inner wall of the butterfly valve body, and a second reset spring is arranged between the first piston block and the inside of the mounting cylinder sleeves. Unlocking components are installed on the outer walls of both sides of the butterfly valve body, and the unlocking components reset the sealing boss and the first piston block.

Preferably, sealing bosses are provided on both sides of the mounting cylinder sleeves, and second piston blocks are slidably connected inside the sealing cavities on both sides. The outer walls of each two opposite second piston blocks are fixedly connected with limit blocks that pass through the inner wall of the butterfly valve body, and a through hole is provided between the mounting cylinder sleeves and the sealing bosses.

Preferably, the linkage assembly includes a water-contacting disc, a linkage driving plate and a first return spring. The opposite surfaces of the sealing discs on both sides are rotatably connected with the first piston blocks. The ends of the linkage driving plates on both sides are rotatably connected with the water-contacting discs. The outer walls of the sliding pins on both sides are fixedly connected with the limiting bosses. A first return spring is arranged between the limiting bosses and the sliding bosses on both sides.

Preferably, the outer wall of the water contact disc facing the water flow is concave.

Preferably, the water contact disc is provided with a plurality of water permeable holes on the outer wall close to the sealing disc, and each water permeable hole passes through the water contact disc.

Preferably, the unlocking assembly includes an electric telescopic rod and a reset disc, the outer walls of both sides of the butterfly valve body are detachably connected with the electric telescopic rod, and the mounting cylinder sleeves on both sides are provided with penetrating sealing bosses near the outer walls of the butterfly valve body, and the telescopic ends of the electric telescopic rods on both sides pass through the sealing bosses to reach the interior of the mounting cylinder sleeves.

Preferably, the telescopic ends of the electric telescopic rods on both sides are detachably connected with reset discs.

Compared with the prior art, the present invention has the following beneficial effects:

1. The water-contacting disc in the linkage assembly is oriented toward the direction of water flow, and the water pressure causes the water-contacting disc to move toward the driving connecting shaft, and the linkage driving plates on both sides cooperate to make the sliding pins on both sides move toward the outside inside the sliding boss, so that the ends of the sliding pins on both sides can contact the inner wall of the butterfly valve body, and the first return spring is forced to shrink. The friction between the end of the sliding pin and the inner wall of the butterfly valve body makes the sealing disc more stable inside the butterfly valve body. After the driving connecting shaft is loosened, the sealing disc can still keep a seal against water, and the design of the inner concave surface of the water-contacting disc can increase the contact area with water.

2. The arrangement of multiple water-permeable holes enables water to pass through each water-permeable hole when the sealing disc is opened, thereby reducing the influence of the water-contacting disc on the flow rate.

3. The tip of the water diverter tip is used to divert water to the surrounding areas, so that the water pressure is evenly contacted on the outer wall of the sealing disc near the outer edge, making the surface pressure of the sealing disc even and less likely to rotate, thereby increasing the sealing effect.

4. The sliding pin shaft is extended outward and then inserted into the sealing bosses on both sides, so that the sealing bosses on both sides shrink inward and compress the second return spring, thereby limiting the position of the sliding pin shafts on both sides and making them more stable.

5. When the sealing boss and the first piston block move inward, the air inside the cylinder sleeve is squeezed toward the sealing boss, so that each limit block can be squeezed outward on both sides of the sliding pin. After the sliding pin is pulled out, the first piston block and the sealing boss are reset, so that the pressure inside the sealing boss is reduced, causing the limit blocks on both sides to retract.

6. The electric telescopic rod in the unlocking assembly is extended to drive the reset disc to move inside the mounting cylinder sleeve, thereby resetting the first piston block and the sealing boss, and then resetting the sliding pin, so that the sealing disc can rotate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a three-eccentric butterfly valve capable of bidirectional sealing in the present invention;

FIG2 is a schematic diagram of the structure of the water contact disc in the present invention;

FIG3 is a schematic diagram of the structure of the water-dividing tip in the present invention;

FIG4 is a schematic cross-sectional view of the butterfly valve body of the present invention;

FIG5 is a schematic diagram of the enlarged structure of point A in FIG4 of the present invention;

FIG. 6 is a schematic diagram of the installation structure of the electric telescopic rod and the reset disc in the present invention.

The corresponding relationship between the illustrations and component names in the figure is as follows:

100, butterfly valve body; 101, connecting flange; 102, sealing disc; 103, transmission housing;

104. Adjusting hand wheel; 105. Driving connecting shaft;

200, water contact disc; 201, linkage drive plate; 202, sliding pin; 203, limiting boss;

204, first return spring; 205, sliding boss; 206, water permeable hole; 207, water diversion tip;

208, sealing cavity; 209, sealing boss; 210, first piston block; 211, through hole;

212, second return spring; 213, second piston block; 214, cylinder sleeve installation; 215, limit block;

300. Electric telescopic rod; 301. Reset disc.

DETAILED DESCRIPTION

In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments. The present invention provides the following embodiments.

As shown in Figure 1, it is a schematic diagram of the structure of a three-eccentric butterfly valve that can be bidirectionally sealed in a preferred embodiment of the present invention. The three-eccentric butterfly valve that can be bidirectionally sealed in this embodiment includes a butterfly valve body 100, and the outer walls on both sides of the butterfly valve body 100 are fixedly connected with connecting flanges 101. The outer wall of the butterfly valve body 100 near the upper end is installed with a transmission housing 103. A driving connecting shaft 105 is rotatably connected at the center of the butterfly valve body 100. The upper end of the driving connecting shaft 105 passes through the butterfly valve body 100 and is detachably connected to the transmission housing 103. The outer wall of the transmission housing 103 is rotatably connected with an adjusting hand wheel 104, and the outer wall of the driving connecting shaft 105 is detachably connected with a sealing disc 102. In this embodiment, the driving connecting shaft 105 is rotated by rotating the adjusting hand wheel 104, so that the sealing disc 102 can be rotated inside the butterfly valve body 100, thereby achieving the effect of opening and closing. The butterfly valve body 100 can be connected to the pipeline through the connecting flange 101.

As shown in FIG2 , it is a schematic diagram of the structure of the water-contacting disc in this embodiment. The outer wall of the sealing disc 102 close to the driving connecting shaft 105 is fixedly connected with sliding bosses 205 on both sides. Sliding pins 202 are slidably connected to the sliding bosses 205 on both sides. The sliding pins 202 are parallel to the outer wall of the sealing disc 102. The opposite surfaces of the sealing discs 102 on both sides are rotatably connected with the first piston blocks 210. The ends of the linkage driving plates 201 on both sides are rotatably connected with the water-contacting disc 200. The outer walls of the sliding pins 202 on both sides are fixedly connected with limiting bosses 203. A first return spring 204 is arranged between the limiting bosses 203 on both sides and the sliding bosses 205. In this embodiment, when the sealing When the sealing disc 102 rotates to seal the water, the water-contacting disc 200 faces the direction of the water flow, and the water pressure causes the water-contacting disc 200 to move toward the driving connecting shaft 105, and cooperates with the linkage driving plates 201 on both sides to make the sliding pins 202 on both sides move toward the outside inside the sliding boss 205, so that the ends of the sliding pins 202 on both sides can contact the inner wall of the butterfly valve body 100, and the first return spring 204 is forced to shrink, and the friction between the ends of the sliding pins 202 and the inner wall of the butterfly valve body 100 makes the sealing disc 102 more stable inside the butterfly valve body 100, and the sealing disc 102 can still keep a seal against water after the driving connecting shaft 105 is loosened.

It is worth noting that the above-mentioned water-contacting disc 200, linkage driving plate 201 and first return spring 204 are the linkage components in this embodiment. The linkage components include but are not limited to the water-contacting disc 200, linkage driving plate 201 and first return spring 204. As long as the components can enable the sliding pins 202 on both sides to move outward at the same time to contact the inner wall of the butterfly valve body 100, they can be applied to this embodiment.

As shown in FIG. 2 , in order to increase the contact area between the water contact disc 200 and water so that it can be better moved by water pressure, in this embodiment, the outer wall of the water contact disc 200 facing the water flow is concave, and the concave surface design can increase the contact area with water.

As shown in Figure 3, it is a schematic diagram of the water-dividing tip structure in this embodiment. The water-contacting disc 200 is provided with a plurality of water-permeable holes 206 on the outer wall close to the sealing disc 102. Each water-permeable hole 206 penetrates the water-contacting disc 200. In this embodiment, the provision of the plurality of water-permeable holes 206 enables water to pass through each water-permeable hole 206 when the sealing disc 102 is opened, thereby reducing the influence of the water-contacting disc 200 on the flow rate.

As shown in FIG. 3 , a water diverter tip 207 is fixedly connected to the outer wall of the sealing disc 102 away from the water contact disc 200. In the present embodiment, by providing the water diverter tip 207, when the water diverter tip 207 faces the direction of the water flow, the water flow can be diverted to the surroundings through the tip portion of the water diverter tip 207, so that the water pressure is evenly contacted on the outer wall of the sealing disc 102 close to the outer edge, so that the surface pressure of the sealing disc 102 is even and it is more difficult to rotate, thereby increasing the sealing effect.

As shown in Figures 4 and 5, they are a schematic diagram of the cross-sectional structure of the butterfly valve body in this embodiment and an enlarged structural diagram at point A in Figure 4. Mounting cylinder sleeves 214 are embedded on both sides of the inner wall of the butterfly valve body 100, and the interior of the mounting cylinder sleeves 214 on both sides is slidably connected with the first piston block 210. The outer walls of the opposite surfaces of the first piston blocks 210 on both sides are fixedly connected with sealing bosses 209. The sealing bosses 209 on both sides pass through the inner wall of the butterfly valve body 100, and a second return spring 212 is arranged between the first piston block 210 and the interior of the mounting cylinder sleeve 214. In this embodiment, the sliding pins 202 on both sides extend outward and are inserted into the sealing bosses 209 on both sides, so that the sealing bosses 209 on both sides shrink inward and compress the second return spring 212, thereby limiting the position of the sliding pins 202 on both sides to make them more stable.

As shown in Figures 4 and 5, in order to further fix the position of the sealing disc 102, in this embodiment, sealing bosses 209 are arranged on both sides of the mounting cylinder sleeves 214, and the interior of the sealing cavities 208 on both sides is slidably connected with second piston blocks 213, and the outer walls of each two opposite second piston blocks 213 are fixedly connected with limit blocks 215 that penetrate through the inner wall of the butterfly valve body 100, and a through hole 211 is arranged between the mounting cylinder sleeve 214 and the sealing boss 209. In this embodiment, when the sealing boss 209 and the first piston block 210 move inward, the air inside the mounting cylinder sleeve 214 is squeezed toward the sealing boss 209, so that each limit block 215 can be squeezed outward and located on both sides of the sliding pin 202. After the sliding pin 202 is pulled out, the first piston block 210 and the sealing boss 209 are reset, so that the pressure inside the sealing boss 209 is reduced, so that the limit blocks 215 on both sides retract.

As shown in Figures 5 and 6, they are an enlarged structural schematic diagram of point A in Figure 4 in this embodiment and a schematic diagram of the installation structure of the electric telescopic rod and the reset disc. The outer walls of the butterfly valve body 100 on both sides are detachably connected with electric telescopic rods 300, and the cylinder sleeves 214 on both sides are installed near the outer walls of the butterfly valve body 100. A penetrating sealing boss 209 is provided. The telescopic ends of the electric telescopic rods 300 on both sides pass through the sealing boss 209 to reach the inside of the installation cylinder sleeve 214, and the telescopic ends of the electric telescopic rods 300 on both sides are detachably connected with the reset disc 301. In this embodiment, when the valve needs to be opened, the reset disc 301 is driven to move inside the installation cylinder sleeve 214 by extending the electric telescopic rod 300, so that the first piston block 210 and the sealing boss 209 can be reset, and then the sliding pin 202 can be reset, so that the sealing disc 102 can rotate.

It is worth noting that the above-mentioned electric telescopic rod 300 and reset disc 301 are the unlocking components in this embodiment. The unlocking components include but are not limited to the electric telescopic rod 300 and the reset disc 301. As long as the components can enable the sliding pin 202 to be withdrawn from the sealing boss 209, they can be applied to this embodiment.

Working principle: When the sealing disc 102 is closed, the water-contacting disc 200 faces the direction of water flow, and the water pressure causes the water-contacting disc 200 to move toward the driving connection shaft 105, and cooperates with the linkage driving plates 201 on both sides to make the sliding pins 202 on both sides move outward from the inside of the sliding boss 205, so that the ends of the sliding pins 202 on both sides can contact the inner wall of the butterfly valve body 100, and the first return spring 204 is forced to shrink, and the friction between the ends of the sliding pins 202 and the inner wall of the butterfly valve body 100 makes the sealing disc 102 more stable inside the butterfly valve body 100. After the driving connection shaft 105 is loosened, the sealing disc 102 can still keep a seal against water, and the sliding pins 202 on both sides extend outward and insert into the sealing bosses 209 on both sides, so that the sealing bosses 209 on both sides shrink inward and compress the second return spring 204. The positioning spring 212 can limit the position of the sliding pins 202 on both sides to make them more stable. When the sealing boss 209 and the first piston block 210 move inward, the air inside the mounting cylinder sleeve 214 is squeezed toward the sealing boss 209, so that each limiting block 215 can be squeezed outward and located on both sides of the sliding pin 202. After the sliding pin 202 is withdrawn, the first piston block 210 and the sealing boss 209 are reset, so that the pressure inside the sealing boss 209 is reduced, and the limiting blocks 215 on both sides are retracted. When the valve needs to be opened, the electric telescopic rod 300 is extended to drive the reset disc 301 to move inside the mounting cylinder sleeve 214, so that the first piston block 210 and the sealing boss 209 can be reset, and then the sliding pin 202 can be reset, so that the sealing disc 102 can rotate.

The above content is a further detailed description of the present invention in combination with specific implementation methods. It cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the scope of protection determined by the claims submitted for the present invention.

Claims (9)

1. A three-eccentric butterfly valve capable of bidirectional sealing, comprising a butterfly valve body (100), the outer walls of both sides of the butterfly valve body (100) are fixedly connected with connecting flanges (101), the outer wall of the butterfly valve body (100) near the upper end is equipped with a transmission housing (103), the inner center of the butterfly valve body (100) is rotatably connected with a drive connecting shaft (105), the upper end of the drive connecting shaft (105) passes through the butterfly valve body (100) and is detachably connected to the transmission housing (103), and the transmission housing (103) is provided with a plurality of connecting flanges (101) and a plurality of connecting flanges (101) and a plurality of connecting flanges (101) are provided with the ... 3) is rotatably connected to an adjusting hand wheel (104), and the outer wall of the driving connecting shaft (105) is detachably connected to a sealing disc (102), characterized in that sliding bosses (205) are fixedly connected to both sides of the outer wall of the sealing disc (102) close to the driving connecting shaft (105), and sliding pins (202) are slidably connected to the sliding bosses (205) on both sides, and linkage components are installed on the sliding pins (202) on both sides, and the linkage components enable the sliding pins (202) on both sides to move outward at the same time. 2. The three-eccentric butterfly valve capable of bidirectional sealing according to claim 1 is characterized in that a water diversion tip (207) is fixedly connected to the outer wall of the sealing disc (102) away from the water contact disc (200). 3. The three-eccentric butterfly valve capable of bidirectional sealing according to claim 2 is characterized in that mounting cylinder sleeves (214) are embedded on both sides of the inner wall of the butterfly valve body (100), the first piston block (210) is slidably connected inside the mounting cylinder sleeves (214) on both sides, and sealing bosses (209) are fixedly connected to the outer walls of the opposite surfaces of the first piston blocks (210) on both sides, and the sealing bosses (209) on both sides pass through the inner wall of the butterfly valve body (100), and a second reset spring (212) is arranged between the first piston block (210) and the inside of the mounting cylinder sleeve (214), and unlocking components are installed on the outer walls of both sides of the butterfly valve body (100), and the unlocking components reset the sealing boss (209) and the first piston block (210). 4. The three-eccentric butterfly valve capable of bidirectional sealing according to claim 3 is characterized in that sealing bosses (209) are arranged on both sides of the cylinder sleeves (214) on both sides, the interiors of the sealing cavities (208) on both sides are slidably connected with second piston blocks (213), the outer walls of each two opposite second piston blocks (213) are fixedly connected with limit blocks (215) that pass through the inner wall of the butterfly valve body (100), and a through hole (211) is arranged between the cylinder sleeves (214) and the sealing bosses (209). 5. According to claim 4, the three-eccentric butterfly valve capable of bidirectional sealing is characterized in that the linkage assembly includes a water-contacting disc (200), a linkage driving plate (201) and a first return spring (204), the opposite surfaces of the sealing discs (102) on both sides are rotatably connected with the first piston blocks (210), the ends of the linkage driving plates (201) on both sides are rotatably connected with the water-contacting discs (200), the outer walls of the sliding pins (202) on both sides are fixedly connected with the limiting bosses (203), and the first return springs (204) are arranged between the limiting bosses (203) on both sides and the sliding bosses (205). 6. The three-eccentric butterfly valve capable of bidirectional sealing according to claim 5 is characterized in that the outer wall of the water contact disc (200) facing the water flow is concave. 7. The three-eccentric butterfly valve capable of bidirectional sealing according to claim 6 is characterized in that a plurality of water-permeable holes (206) are provided on the outer wall of the water-contacting disc (200) close to the sealing disc (102), and each water-permeable hole (206) penetrates the water-contacting disc (200). 8. According to claim 7, the three-eccentric butterfly valve capable of bidirectional sealing is characterized in that the unlocking component comprises an electric telescopic rod (300) and a reset disc (301), the outer walls on both sides of the butterfly valve body (100) are detachably connected with the electric telescopic rod (300), and the cylinder sleeves (214) on both sides are installed with penetrating sealing bosses (209) at positions close to the outer walls of the butterfly valve body (100), and the telescopic ends of the electric telescopic rods (300) on both sides pass through the sealing bosses (209) to reach the interior of the installing cylinder sleeves (214). 9. The three-eccentric butterfly valve capable of bidirectional sealing according to claim 8, characterized in that the telescopic ends of the electric telescopic rods (300) on both sides are detachably connected with reset discs (301).