A water conservancy monitoring device for water conservancy projects

Abstract

The present invention discloses a water conservancy monitoring device for water conservancy projects, which relates to the technical field of water conservancy monitoring and includes a buoyancy member; a lifting member; a lifting plate; a supporting plate; a water conservancy monitor; a rotating sleeve; a telescopic column; a stop bar; and a returning member provided on the supporting plate. The returning member gives the rotating sleeve the potential energy to rotate towards the stop bar, and at the same time makes the telescopic column slide towards the outside of the rotating sleeve. In the present invention, when a floating object drifts towards the water conservancy monitor along the water flow, the stop bar is located in front of the water conservancy monitor, so that the floating object will be blocked by the stop bar and cannot contact the water flow monitor. Due to the driving of the water flow on the floating object, the floating object has a force on the stop bar, and then the stop bar has a force on the telescopic column, enabling the telescopic column to drive the rotating sleeve to swing. When swinging, the telescopic column slides towards the inside of the rotating sleeve, so that the floating object is deflected by the stop bar to the outside of the water conservancy monitor and will not contact the water flow monitor as the water flow moves.

Description

Technical Field

[0001] The present invention relates to the technical field of water conservancy monitoring, and specifically to a water conservancy monitoring device for water conservancy projects. Background Art

[0002] Water conservancy projects are the general term for various engineering constructions built to control, utilize, and protect surface and underground water resources and the environment. During the construction of water conservancy projects, it is usually necessary to survey the hydrological conditions of lakes and rivers, that is, use hydrological monitoring equipment to survey water bodies, and the hydrological monitoring equipment generally floats in the water body through a floating board. For example, a water conservancy monitoring device for water conservancy projects disclosed in the Chinese Utility Model Patent Publication No. CN214470807U. In this technology, the hydrological monitoring equipment dives into the water for hydrological survey. However, when large floating objects (such as waterweeds, plastic bags, etc.) drift towards the hydrological monitoring equipment along with the water flow, it may cause the floating objects to block the sensors or monitoring modules of the hydrological monitoring equipment, resulting in a decrease in the detection accuracy of the hydrological monitoring equipment and affecting the survey of water conservancy. Summary of the Invention

[0003] The purpose of the present invention is to provide a water conservancy monitoring device for water conservancy projects to solve the problems raised in the above background art.

[0004] To achieve the above purpose, the present invention provides the following technical solutions:

[0005] A water conservancy monitoring device for water conservancy projects, comprising:

[0006] A buoyancy member and a lifting member installed on the buoyancy member;

[0007] A lifting plate drivingly connected to the lifting member and a supporting plate connected to the lifting plate;

[0008] A water conservancy monitor installed on the top of the supporting plate;

[0009] A rotating sleeve rotatably connected to the bottom of the supporting plate;

[0010] A telescopic column telescopically inserted into the rotating sleeve;

[0011] A blocking strip connected to the end of the telescopic column away from the rotating sleeve;

[0012] A returning member provided on the supporting plate, the returning member imparts a potential energy to the rotating sleeve to rotate towards the blocking strip, and at the same time makes the telescopic column slide towards the outside of the rotating sleeve.

[0013] Through the above technical solution, when a floating object drifts towards the water conservancy monitor along the water flow, the blocking bar is located in front of the water conservancy monitor, so that the floating object will be blocked by the blocking bar and unable to contact the water flow monitor. Since the floating object is driven by the water flow, the floating object has a force on the blocking bar, and then the blocking bar has a force on the telescopic column, enabling the telescopic column to drive the rotating sleeve to swing. When swinging, the telescopic column slides towards the inner side of the rotating sleeve, so that the floating object is deflected by the blocking bar to the outside of the water conservancy monitor and will not contact the water flow monitor as the water flow moves. And since the telescopic column will slide towards the inner side of the rotating sleeve when rotating, the distance between the blocking bar and the water conservancy monitor is reduced, and when the floating object swings with the blocking bar, it also moves horizontally, so that when the floating object is deflected to the outside of the water conservancy monitor, it can be carried away by the water flow and smoothly separated from the blocking bar.

[0014] Further, the lifting member includes a base plate connected above the buoyancy member through a plurality of connecting plates. A lifting cylinder is vertically installed on the top of the base plate, and the cylinder rod of the lifting cylinder is fixedly connected to the top of the lifting plate.

[0015] Through the above technical solution, the lifting cylinder drives the lifting plate to move up and down, thereby enabling the water conservancy monitor to move up and down.

[0016] Further, the lifting plate and the supporting plate are connected by a pull rod.

[0017] Through the above technical solution, the longitudinal distance between the lifting plate and the supporting plate can be adjusted, and thus different models of water conservancy monitors can be adapted for installation.

[0018] Further, a fixed sleeve is fixedly penetrated through the outer wall of the supporting plate. The end face of the fixed sleeve is coaxially rotatably connected to a pivot shaft. One end of the rotating sleeve is fixedly connected to an ear block, and the ear block is fixedly connected to one end of the pivot shaft.

[0019] Through the above technical solution, the pivot shaft rotates on the fixed sleeve, thereby enabling the rotating sleeve to be rotatably connected to the outer wall of the supporting plate.

[0020] Further, the returning member includes a volute spring installed in the fixed sleeve. The two ends of the volute spring are respectively fixedly connected to the periphery of the pivot shaft and the inner cavity wall of the fixed sleeve. One end of the telescopic column penetrating into the rotating sleeve is fixedly connected to a sliding pin. A first waist-shaped hole for inserting the sliding pin is formed on the surface of the supporting plate. The length direction of the first waist-shaped hole forms an angle with the axial direction of the rotating sleeve. A second waist-shaped hole for the sliding pin to freely pass through is formed on the periphery of the rotating sleeve.

[0021] Through the above technical solution, the floating object exerts a force on the blocking bar, which in turn causes the blocking bar to exert a force on the telescopic column, causing the telescopic column to slide within the rotating sleeve. When sliding, the sliding pin slides within the first kidney-shaped hole, causing the telescopic column to drive the rotating sleeve to swing and causing the telescopic column to slide within the rotating sleeve.

[0022] Further, the length dimension of the telescopic column is greater than the length dimension of the side of the support plate adjacent to the rotating sleeve.

[0023] Through the above technical solution, when the telescopic column rotates around the rotation fulcrum of the rotating sleeve on the support plate, the floating object can be toggled to the outside of the support plate.

[0024] Further, two rotating arms are rotatably connected to one end of the telescopic column away from the rotating sleeve through a short shaft. The two rotating arms are symmetrically arranged along the axial direction of the telescopic column. The blocking bar is vertically fixed to one end of the rotating arm away from the short shaft. A rotating member for driving the two rotating arms to rotate is provided on the telescopic column.

[0025] Through the above technical solution, when the telescopic column slides towards the inner side of the rotating sleeve, the rotating member will drive the rotating arms to rotate. When the rotating arms rotate, the two rotating arms will rotate synchronously and in opposite directions, causing the two blocking bars to swing away from each other, so that the blocking bars can unfold the floating object to increase the contact area with the water flow, and thus the floating object can be washed away by the water flow more smoothly.

[0026] Further, a guiding rib plate extending to the outer wall of the blocking bar is fixedly connected to the surface of the rotating arm.

[0027] Through the above technical solution, the guiding rib plate can reinforce the blocking bar and reduce the bending deformation of the blocking bar.

[0028] Further, the rotating member includes a gear portion coaxially and fixedly sleeved on the periphery of the short shaft. A sliding rod is coaxially and slidably inserted into the telescopic column. A rack portion is provided at one end of the sliding rod facing the gear portion. The rack portion is disposed between the two gear portions and meshes with the gear portion. A stop ring is fixedly sleeved at the end of the sliding rod away from the gear portion. A sliding groove for the free passage of the stop ring is provided on the end face of the telescopic column. A spring is provided in the sliding groove, and the spring elastically abuts against the end face of the stop ring.

[0029] Through the above technical solution, when the telescopic column slides towards the inner side of the rotating sleeve, the end of the sliding rod will abut against the inner cavity wall of the rotating sleeve, causing the sliding rod and the telescopic column to be in a relative motion state, causing the gear portion and the rack portion to engage and drive the two rotating arms to rotate, causing the two blocking bars to move away from each other.

[0030] Further, a stopper is connected to one end of the telescopic column away from the stop ring.

[0031] Through the above technical solution, the stopper contacts the gear part, thereby limiting the movement of the sliding rod in the direction of retracting into the inner side of the rotating sleeve.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] 1. In the present invention, when a floating object drifts towards the water conservancy monitor along the water flow, the baffle is located in front of the water conservancy monitor, so that the floating object will be blocked by the baffle and cannot contact the water flow monitor. Since the floating object is driven by the water flow, the floating object has a force on the baffle, and then the baffle has a force on the telescopic column, so that the telescopic column can drive the rotating sleeve to swing. When swinging, the telescopic column slides towards the inner side of the rotating sleeve, so that the floating object is deflected by the baffle to the outside of the water conservancy monitor and will not contact the water flow monitor as the water flow moves. And because when the telescopic column rotates, it will slide towards the inner side of the rotating sleeve, thereby reducing the distance between the baffle and the water conservancy monitor, and making the floating object move horizontally while swinging with the baffle. Thus, when the floating object is deflected to the outside of the water conservancy monitor, it can be carried away by the water flow and smoothly separated from the baffle.

[0034] 2. In the present invention, when the telescopic column slides towards the inner side of the rotating sleeve, the rotating member will drive the rotating arm to rotate. When the rotating arm rotates, the two rotating arms will rotate synchronously in the opposite direction, and then the two baffles will swing away from each other, so that the baffle can spread the floating object to increase the contact area with the water flow, and then the floating object can be washed away by the water flow more smoothly.

[0035] 3. In the present invention, when the telescopic column slides towards the inner side of the rotating sleeve, the end of the sliding rod will abut against the inner cavity wall of the rotating sleeve, so that the sliding rod and the telescopic column are in a relative motion state, causing the gear part and the rack part to engage and drive the two rotating arms to rotate, so that the two baffles move away from each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic diagram of the overall structure of a water conservancy monitoring device for a water conservancy project in the present invention;

[0037] Figure 2 is Figure 1 an enlarged schematic diagram of the partial structure at A in

[0038] Figure 3 is Figure 1 a schematic diagram of the positional relationship from the first perspective in

[0039] Figure 4 is Figure 1 a schematic diagram of the positional relationship of the second perspective in

[0040] Figure 5 a schematic diagram of the positional relationship after the assembly of the rotating sleeve, telescopic column and retaining bar in the present invention;

[0041] Figure 6 is Figure 5 a schematic diagram of the positional relationship of the first perspective in

[0042] Figure 7 is Figure 5 a schematic diagram of the positional relationship of the second perspective in

[0043] Figure 8 is Figure 7 a schematic diagram of the positional relationship after partial structures are cut open in

[0044] Figure 9 a schematic diagram of the positional relationship after the assembly of the telescopic column, rotating arm and retaining bar in the present invention;

[0045] Figure 10 is Figure 9 an exploded view of the structure in

[0046] Figure 11 a sectional view of the telescopic column in the present invention.

[0047] In the figures, the descriptions of each reference numeral are as follows: 1, lifting cylinder; 2, base plate; 3, connecting plate; 4, buoyancy member; 5, lifting plate; 6, water conservancy monitor; 7, support plate; 8, scroll spring; 9, fixed sleeve; 10, rotating sleeve; 11, telescopic column; 12, guide rib plate; 13, retaining bar; 14, first kidney-shaped hole; 15, rotating arm; 16, stop block; 17, gear portion; 18, rack portion; 19, short shaft; 20, pivot shaft; 21, sliding pin; 22, second kidney-shaped hole; 23, sliding rod; 24, spring; 25, sliding groove; 26, stop ring. Detailed Embodiments

[0048] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0049] Please refer to Figure 1 - Figure 11, the present invention provides a technical solution: a water conservancy monitoring device for water conservancy projects, including a buoyancy member 4 that can float on the surface of a lake. The buoyancy member 4 can be an airbag. A fixing ring is installed on the top of the buoyancy member 4. A plurality of connecting plates 3 are connected to the surface of the fixing ring by screws. One end of the plurality of connecting plates 3 away from the fixing ring is commonly connected by screws to a base plate 2. A lifting cylinder 1 is vertically installed on the top of the base plate 2. The cylinder rod of the lifting cylinder 1 penetrates the base plate 2 and slides freely. In addition, the end of the cylinder rod of the lifting cylinder 1 is welded with a lifting plate 5. A pull rod is penetrated through each of the four corners of the surface of the lifting plate 5. A support plate 7 is arranged parallel to the lower part of the lifting plate 5. The lower end of the pull rod penetrates the support plate 7. In addition, a nut is threadedly sleeved on the periphery of the pull rod. The end face of the nut abuts against the surfaces of the lifting plate 5 and the support plate 7, so that the lifting plate 5 and the support plate 7 are connected together. In addition, by screwing the nut on the pull rod, the longitudinal distance between the lifting plate 5 and the support plate 7 can be adjusted. A water conservancy monitor 6 is installed on the top of the support plate 7. In addition, by adjusting the longitudinal distance between the lifting plate 5 and the support plate 7, water conservancy monitors 6 with different external dimensions can be installed on the support plate 7;

[0050] A through groove is opened on the outer wall of one side of the support plate 7. A fixing sleeve 9 is installed in the through groove. A pivot shaft 20 is coaxially rotatably connected to the fixing sleeve 9 through a mounting bearing (as Figure 5 shown). An ear block is slidably sleeved on the lower end of the pivot shaft 20. A through hole for the pivot shaft 20 to freely pass through is opened on the ear block. The through hole is in key connection with the pivot shaft 20. In addition, two snap rings are installed on the periphery of the pivot shaft 20. The two snap rings respectively abut against the two surfaces of the ear block, so that the position of the pivot shaft 20 on the ear block will not change. In addition, a rotating sleeve 10 is fixedly connected to the surface of the ear block, so that the rotating sleeve 10 can swing around the axis of the pivot shaft 20, and thus is horizontally rotatably connected to the support plate 7;

[0051] The fixing sleeve 9 is arranged on the front side in the detection direction of the water conservancy monitor 6. A receiving cavity is opened on the upper end face of the fixing sleeve 9. A scroll spring 8 is installed in the receiving cavity. The inner ring of the scroll spring 8 is wound around the upper end of the pivot shaft 20 and is fixedly connected to the upper end of the pivot shaft 20. The outer ring end of the scroll spring 8 is fixedly connected to the inner wall of the receiving cavity. In this way, when the pivot shaft 20 rotates, the scroll spring 8 can be synchronously elastically contracted or elastically unfolded, and the scroll spring 8 accumulates elastic potential energy. A telescopic column 11 is telescopically inserted into the inner cavity of the rotating sleeve 10. The telescopic column 11 can freely slide in the inner cavity of the rotating sleeve 10. In addition, a sliding pin 21 is vertically fixedly connected to the end of the telescopic column 11 penetrating into the inner cavity of the rotating sleeve 10. The sliding pin 21 penetrates out of the rotating sleeve 10. A first kidney-shaped hole 14 for the sliding pin 21 to freely pass through is opened on the surface of the support plate 7 (as Figure 5As shown in the figure, the length direction of the first kidney-shaped hole 14 forms an angle with the axial direction of the rotating sleeve 10. In addition, a second kidney-shaped hole 22 for the free passage of the sliding pin 21 is provided on the outer wall of the rotating sleeve 10. The length dimension of the telescopic column 11 is greater than the length dimension of the side of the support plate 7 adjacent to the rotating sleeve 10 (refer to Figure 1 , and the length dimension of the telescopic column 11 is greater than the length dimension of the left edge of the support plate 7);

[0052] One end of the telescopic column 11 away from the rotating sleeve 10 is rotatably connected with two rotating arms 15 through a mounting short shaft 19. The two rotating arms 15 are symmetrically arranged along the axial direction of the telescopic column 11. In addition, a retaining bar 13 is vertically fixed at one end of the rotating arm 15 away from the short shaft 19, and a guiding rib plate 12 extending to the surface of the retaining bar 13 is fixed on the outer wall of the rotating arm 15. The guiding rib plate 12 can reinforce the retaining bar 13;

[0053] A gear part 17 is coaxially and fixedly sleeved on the periphery of the short shaft 19. A sliding rod 23 is coaxially and slidably inserted into the telescopic column 11 (as Figure 9 shown). A rack part 18 is provided at one end of the sliding rod 23 facing the gear part 17. The rack part 18 is arranged between the two gear parts 17 and meshes with the gear part 17. A stop ring 26 is fixedly sleeved at one end of the sliding rod 23 away from the gear part 17. A sliding groove 25 for the free passage of the stop ring 26 is provided on the end face of the telescopic column 11. A spring 24 is arranged in the sliding groove 25. The spring 24 elastically abuts against the end face of the stop ring 26. In addition, a stop block 16 is connected to one end of the sliding rod 23 away from the stop ring 26. The stop block 16 is exposed outside the telescopic column 11. The stop block 16 contacts the gear part 17, so as to limit the movement of the telescopic column 11 in the direction towards the rotating sleeve 10.

[0054] The working principle of the present invention:

[0055] In the initial state, the axial direction of the rotating sleeve 10 faces the direction of the water flow. When there are large floating objects in the water body floating towards the water conservancy monitor 6 with the water flow, the floating objects first contact the retaining bar 13, and the retaining bar 13 intercepts the floating objects. Since the floating objects have a force on the retaining bar 13 when the water flow drives the floating objects to drift, the retaining bar 13 drives the telescopic column 11 to slide in the rotating sleeve 10, and the sliding pin 21 slides in the first kidney-shaped hole 14, so that the rotating sleeve 10 swings around the axial direction of the pivot 20 towards the left side of the support plate 7 (refer to Figure 1 ), and the retaining bar 13 deflects the floating objects to the outside of the support plate 7;

[0056] When the telescopic column 11 moves towards the inner side of the rotating sleeve 10, the end of the sliding rod 23 will start to contact the inner cavity wall of the rotating sleeve 10 (as Figure 8As shown), as the telescopic column 11 continues to move, the telescopic column 11 and the sliding rod 23 are in a relative motion state, and the stop ring 26 compresses the spring 24, the spring 24 accumulates elastic potential energy, and at the same time the rack portion 18 is meshed with the gear portion 17 for transmission, thereby driving the gear portion 17 to drive the short shaft 19 to rotate. When the gear portion 17 rotates, it will drive the rotating arm 15 to rotate. When the rotating arm 15 rotates, it will cause the two baffles 13 to rotate in a direction away from each other, thereby causing the two baffles 13 to unfold the float (the two baffles 13 are closed together when they just contact the float, and the two baffles 13 press against the float to fold the float. When the two baffles 13 rotate in a direction away from each other, the float will be unfolded), so that the contact area between the float and the water flow increases, thereby increasing the probability of the float being washed away by the water flow;

[0057] When the floating object is washed away by the water flow, the force on the blocking bar 13 disappears, thereby releasing the elastic potential energy stored in the spiral spring 8, and causing the pivot 20 to drive the rotating sleeve 10 to rotate. During the rotation, the sliding pin 21 will slide in the first waist-shaped hole 14 in the opposite direction, thereby causing the telescopic column 11 to rotate to Figure 1 Location status;

[0058] When the rotating sleeve 10 swings in the reverse direction, the elastic potential energy stored in the spring 24 is released, thereby causing the sliding rod 23 to move in the reverse direction, and causing the gear portion 17 and the rack portion 18 to mesh and rotate in the reverse direction, thereby causing the two rotating arms 15 to rotate in a direction approaching each other, so that the two blocking bars 13 are in a merged state, so as to facilitate the next floating object interception.

[0059] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A water conservancy monitoring device for a water conservancy project, characterized in that: include: A buoyancy member (4) and a lifting member installed on the buoyancy member (4); Driving a lifting plate (5) connected to the lifting member and a supporting plate (7) connected to the lifting plate (5); A hydraulic monitoring instrument (6) mounted on the top of the support plate (7); A rotating sleeve (10) rotatably connected to the bottom of the support plate (7); A telescopic column (11) telescopically inserted into the rotating sleeve (10); A blocking bar (13) connected to an end of the telescopic column (11) away from the rotating sleeve (10); A swinging member is provided on the support plate (7), the swinging member imparting potential energy to the rotating sleeve (10) to rotate in the direction of the blocking bar (13), while causing the telescopic column (11) to slide in the direction of the outside of the rotating sleeve (10).

2. A water conservancy monitoring device for water conservancy projects according to claim 1, characterized in that: The lifting member comprises a base plate (2) connected to the top of the buoyancy member (4) via a plurality of connecting plates (3); a lifting cylinder (1) is vertically mounted on the top of the base plate (2); and a cylinder rod of the lifting cylinder (1) is fixedly connected to the top of the lifting plate (5).

3. A water conservancy monitoring device for water conservancy projects according to claim 1, characterized in that: The lifting plate (5) and the supporting plate (7) are connected via a pull rod.

4. A water conservancy monitoring device for water conservancy projects according to claim 1, characterized in that: A fixing sleeve (9) is fixedly provided on the outer wall of the support plate (7), the end surface of the fixing sleeve (9) is coaxially rotatably connected to a pivot (20), one end of the rotating sleeve (10) is fixedly connected to an ear block, and the ear block is fixedly connected to one end of the pivot (20).

5. A water conservancy monitoring device for water conservancy projects according to claim 4, characterized in that: The swing member comprises a scroll spring (8) installed in the fixed sleeve (9), the two ends of the scroll spring (8) are respectively fixed to the periphery of the pivot shaft (20) and the inner wall of the fixed sleeve (9), one end of the telescopic column (11) inserted into the rotating sleeve (10) is fixed to a sliding pin (21), a first waist-shaped hole (14) for the sliding pin (21) to be inserted is provided on the surface of the support plate (7), the length direction of the first waist-shaped hole (14) forms an angle with the axial direction of the rotating sleeve (10), and a second waist-shaped hole (22) for the sliding pin (21) to pass freely is provided on the periphery of the rotating sleeve (10).

6. A water conservancy monitoring device for water conservancy projects according to claim 1, characterized in that: The length of the telescopic column (11) is greater than the length of the side of the support plate (7) adjacent to the rotating sleeve (10).

7. A water conservancy monitoring device for water conservancy projects according to claim 1, characterized in that: One end of the telescopic column (11) away from the rotating sleeve (10) is rotatably connected to two rotating arms (15) via a short shaft (19); the two rotating arms (15) are symmetrically arranged along the axial direction of the telescopic column (11); the blocking bar (13) is vertically fixed to one end of the rotating arm (15) away from the short shaft (19); and a rotating member for driving the two rotating arms (15) to rotate is provided on the telescopic column (11).

8. A water conservancy monitoring device for water conservancy projects according to claim 7, characterized in that: A guide rib plate (12) extending to the outer wall of the blocking bar (13) is fixedly connected to the surface of the rotating arm (15).

9. A water conservancy monitoring device for water conservancy projects according to claim 7, characterized in that: The rotating member comprises a gear portion (17) coaxially fixedly sleeved on the periphery of the short shaft (19); a sliding rod (23) is coaxially slidably penetrated in the telescopic column (11); a rack portion (18) is provided at one end of the sliding rod (23) facing the gear portion (17); the rack portion (18) is arranged between the two gear portions (17) and meshes with the gear portions (17); a stop ring (26) is fixedly sleeved at one end of the sliding rod (23) away from the gear portion (17); a sliding groove (25) is provided on the end surface of the telescopic column (11) for the stop ring (26) to pass freely; a spring (24) is provided in the sliding groove (25); the spring (24) elastically presses against the end surface of the stop ring (26).

10. A water conservancy monitoring device for water conservancy projects according to claim 9, characterized in that: One end of the telescopic column (11) away from the stop ring (26) is connected to a stop block (16).

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