A hydraulic support at the end of a potash mine working face

Abstract

This utility model relates to the field of coal mining technology, and more particularly to a hydraulic support for the end face of a potash mine, comprising a top beam, straight side guard plates, arc-shaped side guard plates, guard plate jacks, and a column. The straight and arc-shaped side guard plates are hinged to both sides of the top beam and connected to the top beam at their bottoms via guard plate jacks, with the arc-shaped side guard plates located on the side furthest from the working face. The guard plate jacks can drive the straight and arc-shaped side guard plates to rotate vertically to conform to the inner wall of the arched tunnel. The column is located at the bottom of the top beam. The piston rod of the column and the piston rod of the guard plate jacks have a tungsten-based coating in their stroke areas, and the guide sleeves and piston heads of the column and guard plate jacks have a copper-tin alloy coating. This type of end-face hydraulic support can better conform to the inner wall of the arched tunnel, increasing the roof protection area and providing better support. It also effectively improves its resistance to brine corrosion in potash mine working faces.

Description

Technical Field

[0001] This utility model relates to the field of coal mining technology, and in particular to a hydraulic support at the end of a potash mine working face. Background Technology

[0002] In coal mining, end-face hydraulic supports are typically installed at the connection between the longwall mining face and the roadway. Their main function is to maintain the safety of the roof in this critical area and provide access and protection for the smooth advancement of the working face. However, in potash mining, due to the special characteristics of potash deposits, conventional end-face hydraulic supports are no longer sufficient to meet the required working conditions. The roof of potash mining faces is often composed of salt rock, gypsum, or mudstone, which is susceptible to brine erosion or pressure deformation, resulting in poor stability and a high risk of local collapse. Supports must address multiple risks, including preventing collapse and preventing brine seepage. Lightweight hydraulic supports, anchor bolts (resin anchoring), or flexible mesh supports are commonly used to prevent rigid supports from breaking due to surrounding rock deformation. Simultaneously, the roadway end face is designed as an arched structure, utilizing the mechanical advantages of the arch to effectively distribute roof pressure and ensure roadway stability. However, traditional hydraulic supports are mostly flat at the top. When applied to arched tunnels, the roof support area is greatly reduced due to the tunnel's shape, limiting their support to straight sections. They cannot support the curved sections, resulting in extremely low safety and significantly increasing the risk of roof collapse, posing a serious threat to the lives of underground workers. In water-soluble mining, the working face (solution cavity) lacks a solid roof. Controlling the erosion range is crucial to prevent rock instability. Since the roof itself is brine, resisting brine corrosion is a core challenge for support equipment. Equipment must be corrosion-resistant, such as using stainless steel for motors and hydraulic systems, and salt-resistant materials for bearings and seals. Furthermore, due to the high hygroscopicity of dust, high-frequency dust removal equipment is necessary to prevent clumping. Therefore, brine leakage / flooding (the most fatal risk), rock collapse, equipment corrosion failure, and electrical faults caused by high humidity are all significant challenges in potash mining.

[0003] Therefore, there is an urgent need for a type of end hydraulic support that is suitable for potash mine working faces, with good support effect and good corrosion resistance. Utility Model Content

[0004] (a) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, this utility model provides a hydraulic support at the end of a potash mine working face, which solves the technical problems of traditional hydraulic supports at the end in arched roadways having a small roof protection area, poor support effect, and inability to resist brine corrosion in potash mine working faces.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the main technical solutions adopted by this utility model include:

[0008] This utility model provides a hydraulic support for the end of a potash mine working face, used to be installed at the center of an arched roadway near the working face. It includes a top beam, straight side guards, curved side guards, guard jacks, and a column. The straight and curved side guards are hinged to both sides of the top beam and connected to the top beam at their bottoms via guard jacks, with the curved side guards located on the side furthest from the working face. The guard jacks can drive the straight and curved side guards to pitch and rotate vertically to conform to the inner wall of the arched roadway. The column is located at the bottom of the top beam. The piston rod of the column and the piston rod of the guard jack have a tungsten-based coating in their stroke areas, and the guide sleeves and piston heads of the column and the guard jack have a copper-tin alloy coating.

[0009] Optionally, the inner sides of both sides of the top beam are provided with embedded ear plates. The straight side guard plate and the arc-shaped side guard plate extend outward in the direction close to the top beam to form lugs corresponding to the embedded ear plates. The embedded ear plates and the lugs are hinged together by connecting pins.

[0010] Optionally, the connecting pin is provided with an axial grease channel filled with water-resistant lubricant, and a plurality of oil passage holes are uniformly provided on its surface, and the plurality of oil passage holes are connected to the grease channel.

[0011] Optionally, the arc-shaped side guard plate includes at least two arc-shaped plates arranged sequentially from the end connected to the top beam to the non-connected end, and a rotary drive mechanism. Adjacent arc-shaped plates are rotatably connected via a hinge shaft. The fixed end and output end of the rotary drive mechanism are respectively connected to the two adjacent arc-shaped plates, used to drive the two adjacent arc-shaped plates to rotate relative to each other to conform to the inner wall of the arched tunnel. A mechanical locking device is provided on the output shaft or hinge shaft of the rotary drive mechanism to lock the relative position of the two adjacent arc-shaped plates.

[0012] Optionally, the thickness of the tungsten-based coating on the piston rod of the upright and the protective plate jack is between 0.05mm and 0.06mm. The thickness of the copper-tin alloy coating on the guide sleeve of the upright is between 0.03mm and 0.05mm, and the thickness of the copper-tin alloy coating in other locations is between 0.02mm and 0.04mm.

[0013] Optionally, the column is equipped with a mechanical extension rod, which has a copper-tin alloy coating with a thickness between 0.02mm and 0.04mm.

[0014] Optionally, it also includes a split base and a bridge plate. The split base includes a left base and a right base arranged symmetrically. The left base and the right base are respectively connected to the top beam through columns, and the left base and the right base are hinged together through the bridge plate.

[0015] Optionally, the bridge plate has an arch-shaped structure, with vertical elongated holes at the connection points with the bases on both sides. The left and right bases are connected to the elongated holes by pins, allowing them to slide and offset vertically. Two sets of bridge plates are arranged in parallel between the left and right bases.

[0016] Optionally, two mounting positions for the jacks are provided on both the left and right bases. One position is located at the center of the two stiffening plates of the left / right base, and the other position is located on the outer side of the stiffening plate at the end away from the bridge plate. The two jacks can be selectively installed at either mounting position on the left or right base.

[0017] (III) Beneficial Effects

[0018] The beneficial effects of this utility model are:

[0019] This invention relates to a hydraulic support at the end of a potash mine working face. Since the roadway at the fully mechanized mining face of a potash mine is arched, the side of the arched roadway closest to the working face is excavated to a straight state during construction. To ensure that the hydraulic support at the end can provide sufficient support in this arched roadway, this invention designs the side plates on both sides of the hydraulic support as follows: one side is a straight side plate, and the other side is an arc-shaped side plate. This allows for better contact with the inner wall of the arched roadway, thereby increasing the roof support area and providing a better support effect. Simultaneously, a specific anti-corrosion coating is applied to components such as the columns and support jacks, which effectively improves the hydraulic support's resistance to brine corrosion in the potash mine working face. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a hydraulic support at the end of a potash mine working face, according to the present invention, applied to a fully mechanized potash mine working face.

[0021] Figure 2 This is a schematic diagram of Embodiment 1 of a hydraulic support at the end of a potash mine working face according to the present invention;

[0022] Figure 3 for Figure 2 Front view of the end hydraulic support in the middle;

[0023] Figure 4 for Figure 2 Side view of the end hydraulic support in the middle;

[0024] Figure 5 for Figure 2 A top view of the hydraulic support at the end of the structure (concealing components such as the top beam, side guards, and front beam);

[0025] Figure 6 for Figure 2 A bottom view of the top beam and side guard plate of the hydraulic support at the end of the structure;

[0026] Figure 7 for Figure 2 A top view of the arc-shaped side guard plate of the hydraulic support at the end of the structure;

[0027] Figure 8 This is a schematic diagram of the arc-shaped side guard plate of Embodiment 2 of a hydraulic support for the end of a potash mine working face according to the present invention.

[0028] [Explanation of Labels in the Attached Image]

[0029] 1: Top beam; 11: Embedded ear plate;

[0030] 2: Straight side panels;

[0031] 3: Curved side guard plate; 31: Lug; 32: Curved plate; 33: Hinge shaft;

[0032] 4: Protective plate jack;

[0033] 5: Columns;

[0034] 6: Move the jack;

[0035] 7: Front beam;

[0036] 8: Split base;

[0037] 9: Bridge plate;

[0038] 10: Working surface;

[0039] 20: Arched tunnel. Detailed Implementation

[0040] To better explain and facilitate understanding of this utility model, a detailed description of its specific embodiments is provided below with reference to the accompanying drawings. In this document, directional terms such as "upper," "lower," "left," and "right" are used interchangeably. Figure 1 The orientation is used as a reference.

[0041] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0042] Example 1:

[0043] Reference Figure 1 Because the roadway at the fully mechanized mining face of the potash mine is an arched roadway 20, and the roof of the arched roadway 20 differs from that of a traditional rectangular roadway, its roof has large arc shapes on both sides. When traditional end hydraulic supports with straight side plates on both sides are applied to this arched roadway 20, they can only support a small straight section of the roadway roof. The support area is small, and it cannot support the large arc sections of the roadway, which can easily lead to collapse accidents and cannot provide comprehensive safety protection for underground workers and equipment. However, in the actual construction process, the side of the arched roadway 20 closest to the working face 10 will be excavated to a straight state along with the working face 10 during construction. In other words, the final shape of the arched roadway 20 should only have a large arc shape on the side away from the working face 10.

[0044] like Figures 2 to 5 As shown, in order to be applicable to this type of roadway structure and achieve a better support effect, this embodiment proposes a hydraulic support at the end of a potash mine working face, which is installed at the center of the arched roadway 20 near the working face 10. This hydraulic support includes a top beam 1, a straight side guard plate 2, an arc-shaped side guard plate 3, two guard plate jacks 4, two columns 5, two pushing jacks 6, a supporting front beam 7, and a split base 8.

[0045] The straight side guard plate 2 and the curved side guard plate 3 are hinged to both sides of the top beam 1, with the straight side guard plate 2 located on the side closer to the working surface and the curved side guard plate 3 located on the side farther from the working surface. Specifically, as follows... Figure 6 As shown, embedded ear plates 11 are provided on the inner sides of both sides of the top beam 1. The straight side guard plate 2 and the arc-shaped side guard plate 3 extend outwards from the direction near the top beam 1 to form lugs 31 corresponding to the embedded ear plates 11. Each lug 31 has a circular hole of the same size and position as the mounting hole on the embedded ear plate 11. The embedded ear plate 11 and the lugs 31 are hinged together by a connecting pin. This connecting pin has an axial grease channel filled with water-resistant lubricant, and multiple oil passage holes are evenly distributed on its surface, communicating with the grease channel. The grease can evenly penetrate the surface of the connecting pin through the oil passage holes, thereby reducing friction between the connecting pin and the embedded ear plates 11 and the lugs 31. During long-term use, this reduces the wear of parts, preventing the connecting pin from jamming or being damaged due to excessive friction, thus ensuring the smooth rotation of the straight side guard plate 2 and the arc-shaped side guard plate 3, reducing equipment maintenance frequency, and improving equipment operating efficiency.

[0046] Because the arc-shaped side guard plate 3 has a large unfolded area, in order to ensure its own strength and the connection strength between it and the top beam 1, such as Figure 7As shown, the inner surface of the arc-shaped side guard plate 3 is provided with several mutually perpendicular intersecting transverse and longitudinal stiffeners. Each longitudinal stiffener includes at least two first vertical ribs located at the left and right ends of the arc-shaped side guard plate 3 and two second vertical ribs evenly distributed between the two first vertical ribs. In this embodiment, two transverse stiffeners and four longitudinal stiffeners are preferably provided. The longitudinal stiffeners include two first vertical ribs located at the left and right ends of the arc-shaped side guard plate 3 and two second vertical ribs distributed between the two first vertical ribs. The four longitudinal stiffeners and two transverse stiffeners are distributed as evenly as possible on the inner surface of the arc-shaped side guard plate 3 to achieve better support and reinforcement. Furthermore, the lug 31 can be integrated with the two second vertical ribs located in the middle of the arc-shaped side guard plate 3, effectively improving the connection strength of the lug 31. If the load-bearing requirements of the arc-shaped side guard plate 3 are higher, reinforcing lug plates can be welded to the left and right sides of each lug 31 to further improve the connection strength between the arc-shaped side guard plate 3 and the top beam 1. One end of the reinforcing ear plate is identical in shape and size to the lug 31, and it has a mounting hole that is coaxial with and the same size as the circular hole on the lug 31. When welding the reinforcing ear plate, its sidewall should be tightly against the sidewall of the lug 31, and the mounting holes on both should be perfectly aligned. The other end of the reinforcing ear plate extends into the surface of the arc-shaped side guard plate 3 and is simultaneously welded and fixed to the inner surface of the arc-shaped side guard plate 3. This reinforcing ear plate can strengthen and disperse stress at the connection between the arc-shaped side guard plate 3 and the top beam 1, preventing excessive stress at the connection point from causing stress concentration on the lug 31 and easily leading to fatigue and other problems.

[0047] The flat side guard plate 2 and the curved side guard plate 3 are connected to the top beam 1 at their bottoms via guard plate jacks 4. These guard plate jacks 4 can drive the flat side guard plate 2 and the curved side guard plate 3 to rotate vertically to fit against the wall of the arched tunnel 20. When the guard plate jacks 4 retract, they can pull the flat side guard plate 2 and the curved side guard plate 3 to a vertical position. When the guard plate jacks 4 extend, they can push the flat side guard plate 2 and the curved side guard plate 3 to a horizontal position.

[0048] The column 5 is located at the bottom of the top beam 1, with its upper end connected to the top beam 1 and its lower end connected to the split base 8. It plays a major supporting role between the roof and floor of the roadway. The column 5 is also equipped with a mechanical extension rod to expand the adjustment range and adapt to different coal seam thickness variations. The split base 8 includes a symmetrically arranged left base and a right base, which are connected to the top beam 1 via the column 5. The left and right bases are hinged together by a bridge plate 9. The bridge plate 9 has an arched structure, and each of its connection points with the two bases has a vertically oriented elongated hole. The left and right bases are connected to these elongated holes by pins, which can slide vertically within the holes, allowing the column 5 to automatically adjust its position to adapt to the unevenness of the floor in the potash mine roadway. This ensures consistent support for the roadway roof and prevents instability caused by uneven floor surfaces, effectively improving the overall stability and reliability of the end hydraulic support. Preferably, two sets of bridge plates 9 are arranged in parallel between the left base and the right base for connection.

[0049] Two jacks 6 are horizontally mounted on the left and right bases, respectively. Each base has two mounting positions: one at the center of the two stiffening plates, and the other on the outer side of the stiffening plate furthest from the bridge plate 9. The two mounting positions are at different distances from the centerline of the split base 8. The two jacks 6 can be selectively installed at either position on the left or right base. Two sets of jack 6 mounting positions are pre-set. During construction, the mounting positions of the jacks 6 can be freely selected according to the layout of the underground supports and the location of the supporting equipment to achieve better support.

[0050] Furthermore, the mining and processing environment of potash mines (such as potassium chloride and potassium sulfate mines) poses a significant risk of corrosion to equipment materials. This is because the roof of the working face in potash mines is often composed of salt rock, gypsum, or mudstone, and the ore layer and slurry contain a large amount of electrolytes such as potassium and sodium salts, which can easily trigger electrochemical corrosion of metal equipment (such as oxygen corrosion and localized pitting corrosion of steel). Moreover, during underground mining, the high humidity environment combined with the crystallization-dissolution cycle of mineral salts accelerates the corrosion failure of equipment surfaces. Therefore, in this embodiment, tungsten-containing coatings (such as tungsten alloy coatings or tungsten-tungsten carbide composite coatings) or copper-tin alloy coatings are prepared on the surface of key equipment using processes such as electroplating and thermal spraying.

[0051] For exposed components of underground mining equipment that are prone to wear and corrosion, a tungsten-based wear-resistant and corrosion-resistant coating is used, providing both wear resistance and salt corrosion resistance. Specifically, a tungsten-based coating is applied to the stroke areas of the piston rod of the column 5 and the piston rod of the jack 4, with a thickness between 0.05mm and 0.06mm. The tungsten-based coating has high density, physically isolating the substrate from high-salt slurry and humid air, preventing electrochemical corrosion. Simultaneously, tungsten has good salt resistance and is not easily dissolved or oxidized in high-concentration potassium salt solutions, effectively addressing corrosion problems in high-salt and humid environments, extending equipment lifespan, and is particularly valuable in scenarios with high environmental protection requirements and high equipment maintenance costs.

[0052] For other parts requiring corrosion protection, a copper-tin alloy coating can be used. Specifically, a copper-tin alloy coating with a thickness between 0.03mm and 0.05mm is applied to the guide sleeve of column 5; a copper-tin alloy coating with a thickness between 0.02mm and 0.04mm is applied to the piston head and mechanical extension rod of column 5, as well as the guide sleeve and piston head of the protective plate jack 4; and a copper-tin alloy coating with a thickness between 0.02mm and 0.04mm is applied to the inner bore of the cylinder of the push jack 6 (including the inner stop and threaded parts). The tin content in all copper-tin alloy coatings is ≥6%.

[0053] The end hydraulic support shown in this embodiment features a flat side guard plate 2 and an arc-shaped side guard plate 3 at the top, which, in conjunction with the top beam 1, better conform to the inner wall of the arched roadway 20, providing better support and improving operational safety. The split base 8 at the bottom better adapts to uneven or undulating roadway floors, allowing the end hydraulic support to safely pass over floor plates with bulging working surfaces, improving its adaptability to complex geological conditions and ensuring stability and safety. Furthermore, anti-corrosion coatings are applied to key components such as the columns, jacks, and other critical parts, effectively enhancing the end hydraulic support's resistance to brine corrosion in potash mine working faces and extending equipment lifespan.

[0054] Example 2:

[0055] Reference Figure 8 This embodiment proposes a hydraulic support at the end of a potash mine working face. The difference between this embodiment and Embodiment 1 is that the arc-shaped side guard plate 3 is a split structure. All other parts are the same as in Embodiment 1, and will not be described again here.

[0056] Specifically, the arc-shaped side guard plate 3 includes at least two arc-shaped plates 32 arranged sequentially from the end connected to the top beam 1 to the non-connected end, and a rotary drive mechanism. Adjacent arc-shaped plates 32 are rotatably connected by a hinge shaft 33. The fixed end and output end of the rotary drive mechanism are respectively connected to the two adjacent arc-shaped plates 32, driving them to rotate relative to each other to conform to the inner wall of the arched tunnel 20. This rotary drive mechanism can be an axial piston hydraulic motor or a gear and rack rotary cylinder, etc. Simultaneously, a mechanical locking device is provided on the output shaft or hinge shaft 33 of the rotary drive mechanism to lock the relative position of the two adjacent arc-shaped plates 32. This mechanical locking device can be implemented by a pin positioning method, for example, including a hydraulically driven pin and a positioning hole on the arc-shaped plate 32. After the arc-shaped plate 32 rotates into position, the pin is inserted into the positioning hole to achieve rigid locking. This type of split-type arc-shaped side guard plate 3 can better meet the needs of various arched tunnels 20, so that the outer surface of the arc-shaped side guard plate 3 can better fit with the inner wall surface of the roof of the arched tunnel 20, so as to provide a larger effective support area and better support effect.

[0057] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0058] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0059] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "beneath" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0060] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0061] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A hydraulic support at the end of a potash mine working face, characterized in that: The end hydraulic support is used to be set at the center of the arched roadway (20) near the working face (10), including a top beam (1), a straight side guard plate (2), an arc-shaped side guard plate (3), a guard plate jack (4) and a column (5). The flat side guard plate (2) and the arc-shaped side guard plate (3) are respectively hinged to the two sides of the top beam (1), and are respectively connected to the top beam (1) at the bottom of the two by the guard plate jack (4), wherein the arc-shaped side guard plate (3) is located on the side away from the working surface; The jack (4) can drive the straight side guard plate (2) and the arc-shaped side guard plate (3) to pitch and rotate in the vertical direction to fit the inner wall of the arched tunnel (20); The column (5) is located at the bottom of the top beam (1); The piston rod of the column (5) and the piston rod of the guard plate jack (4) are both coated with tungsten-based coating, and the guide sleeve and piston head of the column (5) and the guide sleeve and piston head of the guard plate jack (4) are both coated with copper-tin alloy.

2. The hydraulic support at the end of a potash mine working face as described in claim 1, characterized in that: The inner sides of both sides of the top beam (1) are provided with embedded ear plates (11). The flat side guard plate (2) and the arc-shaped side guard plate (3) extend outward in the direction close to the top beam (1) to form a lug (31) corresponding to the embedded ear plate (11). The embedded ear plate (11) and the lug (31) are hinged together by a connecting pin.

3. The hydraulic support at the end of a potash mine working face as described in claim 2, characterized in that: The connecting pin has an axial grease channel filled with water-resistant lubricant, and a plurality of oil passage holes are uniformly provided on its surface, and the plurality of oil passage holes are connected to the grease channel.

4. The hydraulic support at the end of a potash mine working face as described in claim 1, characterized in that: The arc-shaped side guard plate (3) includes at least two arc-shaped plates (32) arranged sequentially from the end connected to the top beam (1) to the non-connected end, as well as a rotation drive mechanism; The two adjacent arc-shaped plates (32) are rotatably connected by a hinge shaft (33); The fixed end and the output end of the rotary drive mechanism are respectively connected to two adjacent arc plates (32) to drive the two adjacent arc plates (32) to rotate relative to each other to fit the inner wall of the arched tunnel (20); A mechanical locking device is provided on the output shaft or hinge shaft (33) of the rotary drive mechanism to lock the relative positions of two adjacent arc plates (32).

5. A hydraulic support at the end of a potash mine working face as described in claim 1, characterized in that: The thickness of the tungsten-based coating on the piston rod of the column (5) and the piston rod of the protective plate jack (4) is between 0.05mm and 0.06mm. The thickness of the copper-tin alloy coating on the guide sleeve of the column (5) is between 0.03mm and 0.05mm, and the thickness of the copper-tin alloy coating at other locations is between 0.02mm and 0.04mm.

6. The hydraulic support at the end of a potash mine working face as described in claim 1, characterized in that: The column (5) is provided with a mechanical extension rod, which is coated with a copper-tin alloy with a thickness between 0.02mm and 0.04mm.

7. The hydraulic support at the end of a potash mine working face as described in claim 1, characterized in that: It also includes a split base (8) and a bridge plate (9); The split base (8) includes a left base and a right base arranged symmetrically. The left base and the right base are respectively connected to the top beam (1) through the column (5), and the left base and the right base are hinged together through the bridge plate (9).

8. A hydraulic support at the end of a potash mine working face as described in claim 7, characterized in that: The bridge plate (9) is an arch bridge structure, and there are vertical elongated holes at the connection positions with the bases on both sides. The left base and the right base are respectively connected to the elongated hole by pins so that they can slide and misalign in the vertical direction, and two sets of the bridge plates (9) are arranged in parallel between the left base and the right base.

9. A hydraulic support at the end of a potash mine working face as described in claim 7, characterized in that: It also includes two push jacks (6), which are horizontally mounted on the left base and the right base, respectively; The cylinder bore of the push jack (6) is coated with a copper-tin alloy with a thickness between 0.02 mm and 0.04 mm.

10. A hydraulic support at the end of a potash mine working face as described in claim 9, characterized in that: Two installation positions for the push jack (6) are provided on both the left base and the right base. One is located at the center of the two stiffeners of the left base / right base, and the other is located on the outside of the stiffener at the end away from the bridge plate (9). The two push jacks (6) can be selectively installed at either of the left and right mounting positions on the left and right bases.

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