Single-action telescopic sleeve hydraulic cylinder

Abstract

The utility model relates to the technical field of hydraulic cylinders, and particularly discloses a single-action telescopic sleeve hydraulic cylinder which comprises a cylinder barrel, a multi-stage sleeve arranged in the cylinder barrel in a sleeved and matched mode and a piston rod fixed to the front end of the final-stage sleeve, the sleeve comprises the final-stage sleeve and a secondary sleeve, the final-stage sleeve is installed in the secondary sleeve in a sliding mode, and a first piston is fixed to the rear end of the final-stage sleeve; a plurality of containing grooves are formed in the side wall of the last-stage sleeve in the circumferential direction at intervals, supporting blocks are installed in the containing grooves in a sliding mode, and a plurality of abutting and pushing structures used for abutting and pushing the corresponding supporting blocks to the side wall of the secondary-stage sleeve are arranged in the first piston and the last-stage sleeve. When the last-stage sleeve drives the piston rod to extend to the limiting position, the abutting and pushing structures abut against and push the corresponding supporting blocks to the inner wall of the secondary-stage sleeve, and therefore the dynamic lateral rigidity of the last-stage sleeve is enhanced, micro-amplitude vibration of the sleeve is effectively reduced, the abnormal abrasion rate of a sealing piece is remarkably reduced, and the service life of the sealing piece is prolonged. And meanwhile, the problem of motion clamping stagnation caused by axis deviation of the piston rod is avoided.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of hydraulic cylinders, in particular to a single-acting telescopic sleeve hydraulic cylinder. BACKGROUND

[0002] The single-acting telescopic sleeve hydraulic cylinder is a linear actuator that realizes multi-stage sleeve extension by one-way driving of hydraulic oil and retraction by spring or external load. Its core feature is compact structure, large stroke and small space occupation, and it is widely used in engineering machinery (such as crane boom telescoping), fire ladder, vehicle-mounted lifting platform and other scenes, especially suitable for long-stroke output but limited installation space working conditions. However, the stability and durability of such hydraulic cylinders under dynamic load still face significant challenges.

[0003] The traditional single-acting telescopic sleeve hydraulic cylinder is composed of multiple coaxially nested thin-walled sleeves. The innermost sleeve is fixed to the piston rod, and after the hydraulic oil is injected through a single inlet, it is pushed out in turn by the pressure difference, and when retracted, it is reset by the built-in spring or external mechanical force. The sleeves are prevented from leaking by sealing components (such as O-rings and gaskets), and their movement accuracy and reliability are highly dependent on the machining accuracy and fitting clearance control of the sleeves. However, such a structure has inherent defects in the mechanical properties of the final sleeve when fully extended.

[0004] In the traditional design, the lateral stiffness of the final sleeve completely depends on the bending strength of the sleeve itself and the accuracy of the fitting clearance between the sleeves. Under dynamic load (such as wind vibration, inertial impact) or long-term alternating stress, the final sleeve is prone to micro lateral vibration, causing abnormal wear of the sealing components, movement axis deviation of the piston rod, and local plastic deformation or buckling failure due to stress concentration.

[0005] Although existing technologies attempt to improve stability by increasing wall thickness or reducing fitting tolerance, such methods significantly increase the structure weight and cannot effectively suppress sudden lateral impact, making it more difficult to balance lightweight and dynamic stiffness requirements, severely restricting the reliability and service life of the hydraulic cylinder under complex working conditions. INNOVATION CONTENT

[0006] In order to improve the problems of insufficient dynamic lateral stiffness, abnormal wear of the sealing system and movement axis deviation of the traditional single-acting telescopic sleeve hydraulic cylinder when the final sleeve is fully extended, the application provides a single-acting telescopic sleeve hydraulic cylinder.

[0007] The single-acting telescopic sleeve hydraulic cylinder provided by the application adopts the following technical solutions:

[0008] The utility model provides a single -action telescopic sleeve hydraulic cylinder, including cylinder, multistage sleeve of sleeve cooperation in the cylinder and the piston rod fixed to the front end of last sleeve, the sleeve includes last sleeve and secondary sleeve, the last sleeve is slidably installed in the secondary sleeve and is fixed with first piston at rear end, a plurality of containing grooves are arranged on the circumference of the last sleeve side wall and are spaced, each containing groove is slidably installed with support block, the first piston and last sleeve are provided with a plurality of groups of push structure for pushing corresponding support block to the secondary sleeve side wall.

[0009] Through adopting the technical scheme, when the last sleeve drives the piston rod to extend to the limit position, the push structure pushes the corresponding support block to the inner wall of the secondary sleeve, so that the dynamic lateral stiffness of the last sleeve is enhanced, the slight vibration of the sleeve is effectively reduced, the abnormal wear rate of the sealing element is significantly reduced, and the movement jamming problem caused by the axis offset of the piston rod is avoided.

[0010] Optionally, the push structure comprises a second piston and a push rod, a liquid inlet cavity and a plug-in through slot are arranged at the connection between the second piston and the last sleeve and are communicated with each other, one end of the liquid inlet cavity away from the plug-in through slot extends to the first piston end, the second piston is slidably sealed in the liquid inlet cavity, and one end of the plug-in through slot away from the liquid inlet cavity is communicated with the containing groove;

[0011] The push rod is fixedly installed on one side of the second piston and partially extends into the plug-in through slot, can extend into the containing groove under the pressure of the hydraulic oil, and the end of the push rod and the end of the support block close to each other are provided with matched wedge-shaped inclined surfaces.

[0012] Through the above technical scheme, when the hydraulic oil enters the liquid inlet cavity, the second piston is pushed to move axially, the push rod is driven to slide along the plug-in through slot, and the wedge-shaped inclined surface at the end of the push rod is in contact with the inclined surface of the support block, so that the axial thrust is decomposed into the radial ejection force. Due to the mechanical amplification effect of the wedge angle, the hydraulic oil pressure can be converted into the radial support force. The support block automatically reaches the preset interference amount when the hydraulic cylinder is fully extended. The support force is linearly related to the system pressure, the self-adaptive stiffness adjustment under the dynamic load is realized, and the contradiction between light weight and carrying capacity of the traditional rigid support structure is solved.

[0013] Optionally, a placing cavity is arranged in the containing groove, a first pulling member is arranged in the placing cavity, one end of the first pulling member is fixed to the placing cavity side wall, and the other end is fixedly connected to the support block side wall.

[0014] By adopting the technical scheme, when the hydraulic pressure is released and the thrust structure is retracted, the elastic restoring force of the first pulling member pulls the support block back into the accommodating groove. The support block is quickly reset during the retraction process and does not jam. The structure avoids the failure risk caused by oil pollution or leakage of the traditional pure hydraulic reset mechanism, simplifies the control system, and greatly improves the retraction reliability of the hydraulic cylinder under harsh working conditions.

[0015] Optionally, a plug-in groove is formed on the side of the support block facing the first piston, and a locking structure for locking the position of the support block is arranged in the first piston. When the end of the support block abuts against the inner wall of the secondary sleeve, the locking portion of the locking structure can be plugged into the plug-in groove.

[0016] By adopting the technical scheme, when the support block is completely ejected and contacts the inner wall of the secondary sleeve, the locking portion of the locking structure can be inserted into the plug-in groove of the support block to form a rigid clamping. This locking force can completely resist the retraction trend of the support block, so that the lateral support state can be maintained even if the hydraulic system is accidentally depressurized. This design improves the bending resistance of the hydraulic cylinder under sudden impact load, avoids the oscillation of the support block caused by hydraulic fluctuations, and significantly improves the structural stability under long-period load.

[0017] Optionally, the locking structure includes a locking rod and a pressing rod, and the first piston is provided with a first mounting groove and a second mounting groove for mounting the locking rod and the pressing rod, respectively. The first mounting groove and the second mounting groove are in communication at the ends, the locking rod is slidingly mounted in the first mounting groove, and the end thereof is arranged towards the plug-in groove;

[0018] The side of the second mounting groove away from the first mounting groove is in communication with the liquid inlet cavity, the pressing rod is slidingly mounted in the second mounting groove, and one end thereof is arranged in a wedge-shaped inclined surface corresponding to the end of the locking rod, and the other end is in sliding sealing fit with the inner wall of the second mounting groove.

[0019] By adopting the technical scheme, when the hydraulic oil enters the liquid inlet cavity, the pressing rod is pushed to move axially, the end inclined surface thereof contacts the inclined surface of the locking rod, the hydraulic thrust is converted into the radial extension movement of the locking rod, and the locking rod is inserted into the plug-in groove.

[0020] Optionally, a second pulling member is arranged on the first piston, one end of the second pulling member is fixedly connected with the first piston, the other end is fixedly connected with the peripheral wall of the locking rod, and the second pulling member can provide an acting force for the locking rod to move away from the plug-in groove.

[0021] By adopting the technical scheme, when the hydraulic pressure is released, the elastic force of the second pulling member drives the locking rod to retract and disengage from the insertion slot. This structure improves the unlocking success rate when the hydraulic cylinder retracts, avoids the failure risk of the traditional gravity reset mechanism under inclined working conditions, and expands the installation adaptability of the hydraulic cylinder.

[0022] Optionally, an elastic member is sleeved on the push rod, one end of the elastic member is fixedly connected with the second piston, and the other end is fixedly connected with the end wall of the liquid inlet cavity. Inert gas is arranged in the sealed cavity surrounded by the liquid inlet cavity and the second piston.

[0023] By adopting the technical scheme, the elastic member and the inert gas can make the push rod move again when the last-stage sleeve is completely extended, so that the locking rod is inserted into the insertion slot after the support block completely abuts against the inner side of the secondary sleeve, thereby ensuring the stability of the locking.

[0024] In summary, the present application has at least one of the following beneficial technical effects:

[0025] 1. When the last-stage sleeve drives the piston rod to extend to the limit position, the push structure pushes the corresponding support block to the inner wall of the secondary sleeve, thereby enhancing the dynamic lateral stiffness of the last-stage sleeve, effectively reducing the slight vibration of the sleeve, significantly reducing the abnormal wear rate of the sealing element, and avoiding the movement jamming problem caused by the axis offset of the piston rod;

[0026] 2. After the hydraulic oil enters the liquid inlet cavity, the second piston is pushed to move axially, the push rod is driven to slide along the insertion slot, and the wedge-shaped slope at the end of the push rod is in contact with the slope of the support block. After the axial thrust is decomposed into radial ejection force, due to the mechanical amplification effect of the wedge angle, the hydraulic oil pressure can be converted into radial support force. The support block automatically reaches the preset interference amount when the hydraulic cylinder is completely extended, and the support force is linearly related to the system pressure, realizing self-adaptive stiffness adjustment under dynamic load and solving the contradiction between lightweight and carrying capacity of the traditional rigid support structure;

[0027] 3. When the hydraulic pressure is released and the push structure retracts, the elastic recovery force of the first pulling member pulls the support block back into the containing slot, ensuring that the support block is quickly reset during the retraction process without jamming. This structure avoids the failure risk of the traditional pure hydraulic reset mechanism caused by oil pollution or leakage, simplifies the control system, and greatly improves the retraction reliability of the hydraulic cylinder under harsh working conditions;

[0028] 4. When the support block is completely ejected and contacts the inner wall of the secondary sleeve, the locking part of the locking structure can be inserted into the insertion slot of the support block, forming a rigid clamping, and this locking force can completely resist the retraction tendency of the support block, so that the lateral support state can be maintained even if the hydraulic system accidentally loses pressure. This design improves the bending resistance of the hydraulic cylinder under sudden impact load, avoids the oscillation of the support block caused by hydraulic fluctuations, and significantly improves the structural stability under long-period load. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0030] Figure 1 is the overall structure diagram of the single-acting telescopic sleeve hydraulic cylinder in the embodiment of the present application;

[0031] Figure 2 is Figure 1 the internal structure diagram of the single-acting telescopic sleeve hydraulic cylinder in

[0032] Figure 3 is Figure 2 the internal structure diagram of the connection between the final sleeve and the first piston in

[0033] Reference signs: 1, cylinder barrel; 11, piston rod; 2, secondary sleeve; 3, final sleeve; 31, containing groove; 32, support block; 321, insertion slot; 33, first piston; 4, pushing structure; 41, second piston; 42, push rod; 421, elastic member; 5, liquid inlet cavity; 6, insertion through groove; 7, placement cavity; 71, first pulling member; 8, locking structure; 81, locking rod; 811, second pulling member; 82, pressing rod. DETAILED DESCRIPTION

[0034] The present application will be further described below in combination with the Figures 1-3

[0035] The embodiment of the present application discloses a single-acting telescopic sleeve hydraulic cylinder.

[0036] The single-acting telescopic sleeve hydraulic cylinder, referring to Figure 1 , Figure 2 and Figure 3 ​, including a cylinder 1, a plurality of sleeve levels sleeved in the cylinder 1, and a piston rod 11 fixed to the front end of the last sleeve 3, the sleeve levels include the last sleeve 3 and the secondary sleeve 2, the last sleeve 3 is slidingly installed in the secondary sleeve 2 and has the first piston 33 fixed to the rear end, a plurality of accommodating grooves 31 are spaced apart in the circumferential direction on the side wall of the last sleeve 3, and each of the accommodating grooves 31 slidingly installs the support block 32, and the first piston 33 and the last sleeve 3 are provided with a plurality of sets of pushing structures 4 for pushing the corresponding support block 32 to the side wall of the secondary sleeve 2.

[0037] When the last sleeve 3 drives the piston rod 11 to extend to the limit position, the pushing structure 4 pushes the corresponding support block 32 to the inner wall of the secondary sleeve 2, so that the dynamic lateral stiffness of the last sleeve 3 is enhanced, the micro-vibration of the sleeve is effectively reduced, the abnormal wear rate of the sealing element is significantly reduced, and the movement jamming problem of the piston rod 11 caused by the axis offset is avoided.

[0038] Referring to Figure 2 and Figure 3 , the pushing structure 4 includes the second piston 41 and the push rod 42, the connection part of the second piston 41 and the last sleeve 3 is respectively provided with the liquid inlet cavity 5 and the insertion through groove 6 which are in communication with each other, one end of the liquid inlet cavity 5 away from the insertion through groove 6 extends to the end of the first piston 33, the second piston 41 is slidingly and sealingly arranged in the liquid inlet cavity 5, and one end of the insertion through groove 6 away from the liquid inlet cavity 5 is in communication with the accommodating groove 31.

[0039] The push rod 42 is fixedly installed on one side of the second piston 41 and partially extends into the insertion through groove 6, can extend into the accommodating groove 31 under the pressure of the hydraulic oil, and the end of the push rod 42 and the support block 32 approaching each other is provided with a wedge-shaped inclined surface.

[0040] When the hydraulic oil enters the liquid inlet cavity 5, the second piston 41 is pushed to move axially, drives the push rod 42 to slide along the insertion through groove 6, and the wedge-shaped inclined surface at the end of the push rod 42 is in contact with the inclined surface of the support block 32, so as to decompose the axial thrust into the radial ejection force. Due to the mechanical amplification effect of the wedge angle, the hydraulic oil pressure can be converted into the radial support force. The support block 32 automatically reaches the preset interference amount when the hydraulic cylinder is fully extended. The support force is linearly related to the system pressure, realizes the self-adaptive stiffness adjustment under the dynamic load, and solves the contradiction between the lightweight and the carrying capacity of the traditional rigid support structure.

[0041] The side wall of the accommodating groove 31 is provided with the placing cavity 7, the first pulling member 71 is arranged in the placing cavity 7, the first pulling member 71 is a pulling spring, one end of the first pulling member 71 is fixed to the side wall of the placing cavity 7, the side wall of the support block 32 is integrally connected with the connecting plate, and the other end of the first pulling member 71 is fixedly connected with the connecting plate, so as to be fixedly connected with the side wall of the support block 32.

[0042] When the hydraulic pressure is released and the thrust structure 4 is retracted, the elastic restoring force of the first pulling member 71 pulls the support block 32 back into the accommodating groove 31. This ensures that the support block 32 is quickly reset during retraction and does not jam. This structure avoids the risk of failure of the traditional pure hydraulic reset mechanism due to oil contamination or leakage, simplifies the control system, and significantly improves the reliability of the hydraulic cylinder during retraction in harsh working conditions.

[0043] Referring to Figure 2 and Figure 3 , the side of the support block 32 facing the first piston 33 is provided with a plug-in groove 321, and the first piston 33 is provided with a locking structure 8 for locking the position of the support block 32. When the end of the support block 32 abuts against the inner wall of the secondary sleeve 2, the locking portion of the locking structure 8 can be plugged into the plug-in groove 321.

[0044] When the support block 32 is completely ejected and contacts the inner wall of the secondary sleeve 2, the locking portion of the locking structure 8 can be inserted into the plug-in groove 321 of the support block 32, forming a rigid clamping. This locking force can completely resist the retraction tendency of the support block 32, and can still maintain the lateral support state even if the hydraulic system is accidentally depressurized. This design improves the bending resistance of the hydraulic cylinder under sudden impact load, while avoiding the oscillation of the support block 32 caused by hydraulic fluctuations, significantly improving the structural stability under long-period load.

[0045] Referring to Figure 2 and Figure 3 , the locking structure 8 includes a locking rod 81 and a pressing rod 82, and the first piston 33 is provided with a first installation groove and a second installation groove for installing the locking rod 81 and the pressing rod 82, respectively. The first installation groove and the second installation groove are connected at the end, the locking rod 81 is slidingly installed in the first installation groove, and the end is arranged towards the plug-in groove 321.

[0046] The side of the second installation groove away from the first installation groove is in communication with the liquid inlet chamber 5, the pressing rod 82 is slidingly installed in the second installation groove, and one end is arranged in a wedge-shaped inclined surface corresponding to the end of the locking rod 81. The other end is in sliding sealing fit with the inner wall of the second installation groove.

[0047] After the hydraulic oil enters the liquid inlet chamber 5, it pushes the pressing rod 82 to move axially, and the end inclined surface contacts the inclined surface of the locking rod 81, converting the hydraulic thrust into radial extension movement of the locking rod 81, so that the locking rod 81 is inserted into the plug-in groove 321. In this embodiment, the end of the pressing rod 82 is provided with an elastic expansion part, which can make the pressing rod 82 more stably plug into the plug-in groove 321.

[0048] Referring to Figure 2 and Figure 3The second pulling member 811 is arranged on the first piston 33, and is also a pulling spring. One end of the second pulling member 811 is fixedly connected with the upper end of the first piston 33, and the other end is fixedly connected with the circumferential wall of the locking rod 81, and can provide an acting force for the locking rod 81 to move away from the insertion slot 321.

[0049] When the hydraulic pressure is released, the elastic force of the second pulling member 811 drives the locking rod 81 to retract and disengage from the insertion slot 321. This structure improves the unlocking success rate when the hydraulic cylinder retracts, and avoids the failure risk of the traditional gravity reset mechanism in the inclined working condition, thereby expanding the installation adaptability of the hydraulic cylinder.

[0050] Referring to Figure 2 and Figure 3 Figure 2 Figure 3 The elastic member 421 is sleeved on the push rod 42, and is a compression spring. One end of the elastic member 421 is fixedly connected with the end face of the second piston 41, and the other end is fixedly connected with the end wall of the liquid inlet cavity 5. In the closed cavity surrounded by the liquid inlet cavity 5 and the second piston 41, an inert gas is arranged.

[0051] The elastic member 421 and the inert gas can make the push rod 42 move again when the last-stage sleeve 3 is completely extended, so that the locking rod 81 is inserted into the insertion slot 321 after the support block 32 completely abuts against the inner side of the secondary sleeve 2, thereby ensuring the stability of the locking.

[0052] The implementation principle of the single-acting telescopic sleeve hydraulic cylinder in the embodiment of the application is as follows: when the last-stage sleeve 3 drives the piston rod 11 to extend to the limit position, the hydraulic oil enters the liquid inlet cavity 5, pushes the second piston 41 to move axially, drives the push rod 42 to slide along the insertion slot 6, and the wedge-shaped slope at the end of the push rod 42 is in contact with the slope of the support block 32, so that the axial thrust is decomposed into radial ejection force, thereby pushing the support block 32 to the abutting position with the inner wall of the secondary sleeve 2.

[0053] Then, the hydraulic oil pushes the pressing rod 82 to move axially, the end slope of the pressing rod 82 is in contact with the slope of the locking rod 81, the hydraulic thrust is converted into the radial extension movement of the locking rod 81, the locking rod 81 is inserted into the insertion slot 321, and the locking and fixing of the support block 32 are realized.

[0054] When the hydraulic pressure is released, the elastic force of the second pulling member 811 drives the locking rod 81 to retract and disengage from the insertion slot 321, thereby unlocking the support block 32. The support block 32 is retracted into the accommodating groove 31 under the action of the first pulling member 71, and the lateral support between the last-stage sleeve 3 and the secondary sleeve 2 is released.

[0055] The above are optional embodiments of the application, and do not limit the protection scope of the application. Therefore, any equivalent changes made on the basis of the structure, shape and principle of the application should be covered within the protection scope of the application.

Claims

1. A single acting telescopic sleeve hydraulic cylinder characterized by: The application relates to a cylinder device, which comprises a cylinder (1), a plurality of sleeves sleeved in the cylinder (1), and a piston rod (11) fixed to the front end of the last sleeve (3), wherein the sleeves comprise a last sleeve (3) and a secondary sleeve (2), the last sleeve (3) is slidably arranged in the secondary sleeve (2) and is fixed with a first piston (33) at the rear end, a plurality of accommodating grooves (31) are formed in the side wall of the last sleeve (3) and are spaced apart in the circumferential direction, a supporting block (32) is slidably arranged in each of the accommodating grooves (31), and a plurality of sets of pushing structures (4) are arranged in the first piston (33) and the last sleeve (3) and are used for pushing the corresponding supporting blocks (32) to the side wall of the secondary sleeve (2).

2. A single acting telescopic sleeve hydraulic cylinder according to claim 1, characterized in that: The pushing structure (4) comprises a second piston (41) and a push rod (42), a liquid inlet cavity (5) and a plug-in through groove (6) are formed in the connection part of the second piston (41) and the last sleeve (3) and are in communication with each other, one end of the liquid inlet cavity (5) away from the plug-in through groove (6) extends to the end of the first piston (33), the second piston (41) is slidably arranged in the liquid inlet cavity (5), and one end of the plug-in through groove (6) away from the liquid inlet cavity (5) is in communication with the accommodating groove (31). The push rod (42) is fixedly arranged on one side of the second piston (41) and partially extends into the plug-in through groove (6) and can extend into the accommodating groove (31) under the pressure of hydraulic oil, and the end of the push rod (42) and the end of the supporting block (32) approaching each other are provided with matched wedge-shaped inclined surfaces.

3. A single acting telescopic sleeve hydraulic cylinder according to claim 1, characterized in that: A placing cavity (7) is formed in the side wall of the accommodating groove (31), a first pulling member (71) is arranged in the placing cavity (7), one end of the first pulling member (71) is fixed to the side wall of the placing cavity (7), and the other end is fixedly connected to the side wall of the supporting block (32).

4. A single acting telescopic sleeve hydraulic cylinder according to claim 2, characterized in that: An insertion groove (321) is formed in the side of the supporting block (32) facing the first piston (33), a locking structure (8) for locking the position of the supporting block (32) is arranged in the first piston (33), and when the end of the supporting block (32) abuts against the inner wall of the secondary sleeve (2), the locking part of the locking structure (8) can be plugged into the insertion groove (321).

5. A single acting telescopic sleeve hydraulic cylinder according to claim 4, characterized in that: The locking structure (8) comprises a locking rod (81) and a pressing rod (82), a first mounting groove and a second mounting groove for mounting the locking rod (81) and the pressing rod (82) are respectively formed in the first piston (33), the first mounting groove and the second mounting groove are in communication at the ends, the locking rod (81) is slidably arranged in the first mounting groove and is provided with an end facing the insertion groove (321), one side of the second mounting groove away from the first mounting groove is in communication with the liquid inlet cavity (5), the pressing rod (82) is slidably arranged in the second mounting groove, one end of the pressing rod (82) is provided with a matched wedge-shaped inclined surface corresponding to the end of the locking rod (81), and the other end is slidably and sealingly matched with the inner wall of the second mounting groove.

6. A single acting telescopic sleeve hydraulic cylinder according to claim 5, characterized in that: The first piston (33) is provided with a second pulling member (811), one end of the second pulling member (811) is fixedly connected with the first piston (33), the other end is fixedly connected with the peripheral wall of the locking rod (81), and the second pulling member (811) can provide an acting force for the locking rod (81) to move away from the insertion slot (321).

7. A single acting telescopic sleeve hydraulic cylinder according to claim 2, characterized in that: The push rod (42) is sleeved with an elastic member (421), one end of the elastic member (421) is fixedly connected with the second piston (41), the other end is fixedly connected with the end wall of the liquid inlet cavity (5), and the inert gas is arranged in the closed cavity surrounded by the liquid inlet cavity (5) and the second piston (41).

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