A self-locking cylinder structure for air cut-off

Abstract

This utility model relates to the field of cylinder technology, and in particular to a self-locking cylinder structure for air cut-off, including a cylinder body and a self-locking component for self-locking of the cylinder body when air is cut off. The cylinder body includes a cylinder body and a cylinder piston rod extending upward from the cylinder body. The self-locking component includes a self-locking cylinder body fixed on the upper side of the cylinder body for the cylinder piston rod to pass through upward, and a self-locking limiting annular surrounding cylinder disposed in the self-locking cylinder body, which surrounds the cylinder piston rod and is used to lock the cylinder piston rod when air is cut off and to release the cylinder piston rod when air is supplied. The self-locking limiting annular surrounding cylinder can swing up and down, which is convenient for normal use and has high safety.

Description

Technical Field

[0001] This utility model relates to the field of cylinder technology, and in particular to a self-locking cylinder structure for air cut-off. Background Technology

[0002] In the current manufacturing sector, cylinders are used extensively, especially on automotive parts production lines. Many processing steps require cylinders for positioning and moving workpieces. However, if the cylinder's air supply is interrupted, especially in vertically oriented cylinders, the piston rod may suddenly fall due to gravity, causing damage to the cylinder or workpiece, and even posing safety risks to workers. Existing structures also incorporate many safety features.

[0003] For example, Chinese Patent Application No. 202422824892.9 discloses a cylinder air cut-off self-locking mechanism, including a rear end cover, a cylinder barrel, and a front end cover. The rear end cover and the front end cover are respectively fixedly connected to both ends of the cylinder barrel. A piston head is slidably connected inside the cylinder barrel. One end of the piston head is integrally formed with a piston rod, and the piston rod passes through the front end cover. An air intake component is provided inside the rear end cover to push the piston head to move. An elastic component is provided inside the cylinder barrel to reset the piston head after it has moved. An annular groove is provided on the outer side of the piston rod near the piston head. A sliding groove is provided on the side of the front end cover near the cylinder barrel. An L-shaped bracket is slidably connected inside the sliding groove, and the L-shaped bracket extends into the cylinder barrel and is inserted into the annular groove.

[0004] The existing structure only locks during use. In this case, the continuous force will damage the self-locking structure itself and also affect the normal use of the piston rod. The presence or absence of magnetism must be controlled each time, which generally requires the design of an electromagnetic structure. Furthermore, it is necessary to detect whether the internal gas is cut off before determining whether to contact the magnetic self-locking structure. The negative effects on normal use are even greater. Utility Model Content

[0005] The purpose of this invention is to provide a self-locking cylinder structure that is easy to use and has high safety.

[0006] The above-mentioned objective of this utility model is achieved through the following technical solution: a self-locking cylinder structure for air cut-off, comprising a cylinder body and a self-locking assembly for self-locking the cylinder body when air is cut off. The cylinder body includes a cylinder body and a cylinder piston rod extending upward from the cylinder body. The self-locking assembly includes a self-locking cylinder body fixed on the upper side of the cylinder body for the cylinder piston rod to pass through upward, and a self-locking limiting annular surrounding cylinder disposed in the self-locking cylinder body, which surrounds the cylinder piston rod and is used to lock the cylinder piston rod when air is cut off and to release the cylinder piston rod when air is supplied. The self-locking limiting annular surrounding cylinder can swing up and down.

[0007] As a preferred embodiment of this utility model, the self-locking cylinder body has a self-locking channel and a supporting inner channel that are connected vertically. A bottom sealing plate is embedded in the supporting inner channel to block the lower outlet of the self-locking channel. The lower side of the bottom sealing plate abuts against the upper side of the cylinder body, and the cylinder piston rod passes through the bottom sealing plate. The self-locking limiting annular surrounding cylinder is located within the self-locking channel, and an upper sealing cover is provided within the self-locking channel above the self-locking limiting annular surrounding cylinder. The upper sealing cover passes through the cylinder piston rod. The bottom sealing plate and the self-locking limiting annular surrounding cylinder... A vertical lifting spring is provided between the surrounding cylinders to lift the self-locking limiting annular surrounding cylinder and allow it to swing upwards. The portion of the self-locking channel located between the lower side of the upper sealing cover and the upper side of the self-locking limiting annular surrounding cylinder is used to inflate and form an inflation chamber to flatten the self-locking limiting annular surrounding cylinder before releasing the cylinder piston rod. A fulcrum shaft is fixed on the upper side of the self-locking limiting annular surrounding cylinder, serving as the fulcrum for the self-locking limiting annular surrounding cylinder to swing. The top of the fulcrum shaft abuts against the lower side of the upper sealing cover. The fulcrum shaft and the lifting spring are respectively on both sides of the cylinder piston rod.

[0008] As a preferred embodiment of this invention, the cylinder wall of the self-locking cylinder is provided with an air inlet that communicates with the inflation chamber.

[0009] As a preferred embodiment of this utility model, the outer wall of the self-locking limiting annular surrounding cylinder forms a swinging guide arc surface that slopes downwards and is arched, with the fulcrum shaft and the swinging guide arc surface located on the same side of the cylinder piston rod.

[0010] As a preferred embodiment of this utility model, the self-locking limiting annular surrounding cylinder is provided with a positioning groove extending from the bottom upward for the lifting spring to be inserted, and the lower side of the lifting spring abuts against the bottom cover plate.

[0011] As a preferred embodiment of this utility model, an annular upper sealing groove is provided on the outer wall of the upper sealing cover, and an upper sealing ring is embedded in the upper sealing groove, which abuts against the wall of the self-locking channel and seals the inflation chamber on the upper side. An annular lower sealing groove is provided on the outer wall of the self-locking limiting annular surrounding cylinder, and a lower sealing ring is embedded in the lower sealing groove, which abuts against the wall of the self-locking channel and seals the inflation chamber on the lower side.

[0012] As a preferred embodiment of this utility model, a reset plate is fixed to the side of the self-locking limiting annular surrounding cylinder, located below the lower sealing ring, for the self-locking limiting annular surrounding cylinder to swing and deflect downwards and reset. The reset plate extends out of the self-locking cylinder body from the side. The reset plate and the lifting spring are located on the same side of the cylinder piston rod. The cylinder wall of the self-locking cylinder body has a reset port that is open inside and out and allows the reset plate to pass through and be pushed downwards.

[0013] As a preferred embodiment of this utility model, there is a gap between the part with the largest outer diameter on the outer wall of the self-locking limiting annular surrounding cylinder and the wall surface of the self-locking channel, and there is a gap between the part with the smallest inner diameter on the inner wall of the self-locking limiting annular surrounding cylinder 22 and the cylinder piston rod.

[0014] As a preferred embodiment of this utility model, the upper sealing cover has an annular structure with the inner ring through which the cylinder piston rod passes, and the inner ring of the upper sealing cover has a cylindrical hole with the same diameter as the cylinder piston rod.

[0015] As a preferred embodiment of this utility model, the bottom cover plate is an annular plate with the cylinder piston rod passing through its inner ring vertically, and the inner ring diameter of the bottom cover plate is the same as the diameter of the cylinder piston rod.

[0016] The beneficial effects of this utility model are as follows: Under normal air supply conditions, the self-locking structure does not affect the normal use of the piston rod, thus avoiding interference with normal operation. In the event of a sudden air supply interruption, the structure automatically locks itself, preventing the piston rod from falling suddenly, ensuring high safety. Furthermore, it facilitates reset and reuse. It also strengthens the support and guidance for the cylinder piston rod. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of the cylinder structure in the embodiment;

[0018] Figure 2 yes Figure 1 A three-dimensional structural diagram of the central structure after the protective cover has been removed;

[0019] Figure 3 yes Figure 2 A three-dimensional structural diagram of the central structure after the self-locking cylinder block is removed;

[0020] Figure 4 yes Figure 3 A three-dimensional structural diagram of the central structure after the sealing ring is removed;

[0021] Figure 5 yes Figure 4 A schematic diagram of the three-dimensional structure from the left-hand perspective;

[0022] Figure 6 yes Figure 1 A three-dimensional structural diagram of the self-locking cylinder body with a portion cut open;

[0023] Figure 7 Yes, yes Figure 4 A schematic diagram of the three-dimensional structure after the self-locking limiting ring-shaped surrounding cylinder is removed from the central structure;

[0024] Figure 8 yes Figure 1 A three-dimensional structural diagram of the self-locking cylinder body;

[0025] Figure 9 yes Figure 8 A schematic diagram of the three-dimensional structure from the right-hand perspective;

[0026] Figure 10 yes Figure 1 A schematic diagram of the three-dimensional structure of the self-locking limiting annular surrounding cylinder;

[0027] Figure 11 yes Figure 10 A schematic diagram of the three-dimensional structure from a lower perspective. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings.

[0029] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of the present utility model.

[0030] Examples, such as Figure 1-11As shown, a self-locking cylinder structure for air cut-off includes a cylinder body and a self-locking assembly for self-locking the cylinder body when air is cut off. The cylinder body includes a cylinder body 11 and a cylinder piston rod 12 extending upward from the cylinder body 11. The self-locking assembly includes a self-locking cylinder body 21 fixed to the upper side of the cylinder body 11 for the cylinder piston rod 12 to pass through upward, and a self-locking limiting annular surrounding cylinder 22 disposed within the self-locking cylinder body 21, surrounding the cylinder piston rod 12 and used to lock the cylinder piston rod 12 when air is cut off and release the cylinder piston rod 12 when air is supplied. The self-locking limiting annular surrounding cylinder 22 can swing up and down. The self-locking cylinder body 21 and the self-locking limiting annular surrounding cylinder 22 are added to the conventional cylinder body 11 structure to achieve self-locking when air is cut off. The cylinder piston rod 12 also passes through the self-locking limiting annular surrounding cylinder 22. The self-locking limiting annular surrounding cylinder 22 can deflect by swinging up and down, causing the projection of its inner ring in the vertical direction to change and shrink. This means that when one side of the inner ring of the self-locking limiting annular surrounding cylinder 22 deflects upwards and tilts, it can squeeze and lock the cylinder piston rod 12, generating a lateral squeezing force. This creates friction in the vertical direction, preventing the cylinder piston rod 12 from falling, thus completing the self-locking process and locking the cylinder piston rod 12 to move up and down. Therefore, the tilted state of the self-locking limiting annular surrounding cylinder 22 is the self-locking state. In the relaxed state, the self-locking limiting annular surrounding cylinder 22 is horizontally placed, and the projection of its inner ring in the vertical direction is at its maximum. A space needs to be maintained between the self-locking limiting annular surrounding cylinder 22 and the cylinder piston rod 12. This ensures that the normal operation of the cylinder piston rod 12's lifting and lowering is not affected, while also allowing for swinging and deflection space. There is a gap between the smallest inner diameter part of the inner wall of the self-locking limiting annular surrounding cylinder 22 and the cylinder piston rod 12. This gap is the effective operating space between the self-locking limiting annular surrounding cylinder 22 and the cylinder piston rod 12 in a horizontal state. This gap is different from the tolerance of the bore and shaft and requires a relatively large gap. Generally, the average gap should be controlled at more than 2 mm and preferably around 5 mm. This gap is the gap formed between the self-locking limiting annular surrounding cylinder 22 and the cylinder piston rod 12 in a horizontal state. It disappears when self-locking occurs. When the inner ring of the self-locking limiting annular surrounding cylinder 22 is tilted, it can contact the cylinder piston rod 12 to form a jamming and compressing state.

[0031] In one embodiment of this invention, the self-locking cylinder body 21 has a self-locking channel 211 and a supporting inner channel 212 that are connected vertically. A bottom sealing plate 3 is embedded in the supporting inner channel 212 to block the lower outlet of the self-locking channel 211. The lower side of the bottom sealing plate 3 abuts against the upper side of the cylinder body 11 and the cylinder piston rod 12 passes through the bottom sealing plate 3. The self-locking limiting annular surrounding cylinder 22 is located in the self-locking channel 211, and an upper sealing cover 4 is provided in the self-locking channel 211 above the self-locking limiting annular surrounding cylinder 22. The supporting inner channel 212 should preferably be cylindrical, and the outer perimeter of the bottom sealing plate 3 and the supporting inner channel 212 should preferably be the same as those of the supporting inner channel 212, so that they are perfectly embedded. The self-locking channel 211, from the bottom up to the upper sealing cover 4, is preferably a cylindrical channel with a diameter smaller than that of the supporting inner channel 212. The external dimensions of the self-locking channel 211 at the position of the upper sealing cover 4 and above can be designed according to the outer dimensions of the upper sealing cover 4, so that the upper sealing cover 4 is horizontally locked on the upper side of the self-locking channel 211 and seals the upper outlet of the self-locking channel 211.

[0032] Furthermore, the upper sealing cover 4 allows the cylinder piston rod 12 to pass through. A vertical lifting spring 51, capable of lifting the self-locking limiting annular surrounding cylinder 22, is provided between the bottom sealing cover plate 3 and the self-locking limiting annular surrounding cylinder 22. The portion of the self-locking channel 211 located between the lower side of the upper sealing cover 4 and the upper side of the self-locking limiting annular surrounding cylinder 22 is used for inflation to form an inflation chamber 2110 to flatten the self-locking limiting annular surrounding cylinder 22 before releasing the cylinder piston rod 12. A fulcrum shaft 52, serving as a pivot point for the self-locking limiting annular surrounding cylinder 22 during its swing, is fixed to the upper side of the locking limiting annular surrounding cylinder 22. The top of the fulcrum shaft 52 abuts against the lower side of the upper sealing cover 4. The fulcrum shaft 52 is a cylindrical rod with its axis oriented horizontally. The fulcrum shaft 52 and the lifting spring 51 are located on opposite sides of the cylinder piston rod 12. For example, if the fulcrum shaft 52 is on the left side of the cylinder piston rod 12, then the lifting spring 51 is on the right side of the cylinder piston rod 12. This allows the self-locking limiting annular surrounding cylinder 22 to form an effective swinging and warping action. During normal operation, the pipeline is ventilated, the cylinder body is ventilated, and it can work normally. The inflation chamber 2110, connected to the main pipeline, also contains air. Sufficient air enters the inflation chamber 2110 and reaches sufficient air pressure. The gas generates downward pressure on the upper side of the self-locking limiting annular surrounding cylinder 22, causing the self-locking limiting annular surrounding cylinder 22 to be compressed into a horizontal state. Of course, the upper and lower sides of the self-locking limiting annular surrounding cylinder 22 and the upper side of the bottom sealing plate 3 are preferably flat, so that in the normal relaxed state, the self-locking limiting annular surrounding cylinder 22 and the bottom sealing plate 3 are in close contact and in a horizontal state. The lifting spring 51 is located between the self-locking limiting annular surrounding cylinder 22 and the bottom sealing plate 3 and is compressed. Therefore, during normal operation, the self-locking limiting annular surrounding cylinder 22 does not contact the cylinder piston rod 12 and is in a relaxed state, allowing the cylinder piston rod 12 to move freely up and down and work normally.When an abnormal situation occurs and the main air supply is cut off, the air pressure inside the cylinder is lost, and the cylinder piston rod 12 will suddenly fall. At this time, the air filling chamber 2110 is also in a state of air cut-off. Because there is not enough air pressure to suppress the upper side of the self-locking limiting annular surrounding cylinder 22 after the air is cut off, the lifting spring 51 is stretched open vertically, while the bottom cover plate 3 is limited in the inner channel 212 of the support and cannot move. Therefore, the lifting spring 51 bounces up and lifts the corresponding part of the self-locking limiting annular surrounding cylinder 22, and abuts against the fulcrum shaft 52 on the other side. As a fulcrum, the portion of the self-locking limiting annular surrounding cylinder 22 located on the side of the lifting spring 51 tilts and warps upwards. This causes the inner ring of the self-locking limiting annular surrounding cylinder 22, i.e., part of the inner cylinder wall, to tilt and lock against the cylinder piston rod 12. Originally, when the self-locking limiting annular surrounding cylinder 22 is horizontal, the two parts are not in contact and are separated by a gap. Due to the warping and tilting of the self-locking limiting annular surrounding cylinder 22, the inner ring of the self-locking limiting annular surrounding cylinder 22 tilts, allowing the tilted sides to abut against the sides of the cylinder piston rod 12, creating a compressive force and thus completing the self-locking. Two or more lifting springs 51 can be used, but they must be on the same side.

[0033] To achieve the up-and-down swinging and warping of the self-locking limiting annular surrounding cylinder 22, the following is preferred: there is a gap between the outermost part of the outer wall of the self-locking limiting annular surrounding cylinder 22 with the wall of the self-locking channel 211, and there is a gap between the innermost part of the inner wall of the self-locking limiting annular surrounding cylinder 22 with the cylinder piston rod 12. This allows for swinging space on both the inner and outer sides. As mentioned above, such gaps are only a few millimeters on average. Of course, these two gaps refer to the outer gap space between the self-locking limiting annular surrounding cylinder 22 and the wall of the self-locking channel 211 in the horizontal state, and the inner gap space between the self-locking limiting annular surrounding cylinder 22 and the cylinder piston rod 12.

[0034] Furthermore, the cylinder wall of the self-locking cylinder 21 is provided with an air inlet 2100 that communicates with the air chamber 2110. The air inlet 2100 is connected to the air pipe to the main air supply line. During normal operation, it maintains the air supply state to ensure that the self-locking limiting annular surrounding cylinder 22 is in a horizontally relaxed state.

[0035] As one embodiment of this invention, the outer wall of the self-locking limiting annular surrounding cylinder 22 forms a swing guide arc surface 2200 that is arched downwards. The fulcrum shaft 52 and the swing guide arc surface 2200 are located on the same side of the cylinder piston rod 12, for example, on the left or right side of the cylinder piston rod 12. This forms an arc-shaped transition part during swinging, which can be understood as a rounded corner structure, reducing warping and avoiding damage between the vertical edge design and the bottom cover plate 3.

[0036] Preferably, the self-locking limiting annular surrounding cylinder 22 has a positioning groove 510 extending from the bottom upward for the lifting spring 51 to be inserted. The lower side of the lifting spring 51 abuts against the bottom cover plate 3. The positioning groove 510 is cylindrical, which allows the lifting spring 51 to be hidden. During normal operation, the self-locking limiting annular surrounding cylinder 22 and the bottom cover plate 3 remain in close contact.

[0037] Furthermore, an annular upper sealing groove 401 is provided on the outer wall of the upper sealing cover 4. An upper sealing ring 4011 is embedded in the upper sealing groove 401, which abuts against the wall of the self-locking channel 211 and seals the inflation chamber 2110 on the upper side. An annular lower sealing groove 2201 is provided on the outer wall of the self-locking limiting annular surrounding cylinder 22. A lower sealing ring 22011 is embedded in the lower sealing groove 2201, which abuts against the wall of the self-locking channel 211 and seals the inflation chamber 2110 on the lower side. This ensures that there is no air leakage on the upper and lower sides of the inflation chamber 2110, so that the air pressure is stable and can press the self-locking limiting annular surrounding cylinder 22.

[0038] Preferably, a reset plate 6 is fixed to the side of the self-locking limiting annular surrounding cylinder 22, located below the lower sealing ring 22011, for the self-locking limiting annular surrounding cylinder 22 to swing and deflect downwards to reset. The reset plate 6 extends from the side of the self-locking cylinder body 21, and the reset plate 6 and the lifting spring 51 are located on the same side of the cylinder piston rod 12. The cylinder wall of the self-locking cylinder body 21 has a reset port 61 that is internally and externally connected, allowing the reset plate 6 to pass through and be pushed downwards. This structure is designed so that when a self-locking occurs due to air shortage, the self-locking limiting annular surrounding cylinder 22 will automatically reset. The annular surrounding cylinder 22, located on the spring side, will deflect upwards. Naturally, the lower sealing ring 22011 will also deflect upwards. When ventilation resumes, it's difficult to bring the self-locking limiting annular surrounding cylinder 22 to a horizontal position and compress the lifting spring 51 by directly introducing air into the inflation chamber 2110. This is because the entire structure is tilted, resulting in insufficient sealing due to the deflection. Furthermore, direct air intake on the tilted structure will cause uneven force, making it difficult to flatten and potentially causing damage. Therefore, it needs to be reset to a horizontal position before inflation. This can be achieved by simply pushing the reset plate 6 downwards. Alternatively, a protective cover 66 can be attached to the side of the self-locking cylinder body 21 to block the reset port 61. When reset is needed, the protective cover 66 can be opened for reset, and closed for normal use. The self-locking limiting annular surrounding cylinder 22, fulcrum shaft 52, protective cover 66, reset plate 6, bottom sealing plate 3, and upper sealing cover 4 can all be made of hard materials such as steel.

[0039] Preferably, the upper sealing cover 4 has an annular structure with the cylinder piston rod 12 passing through its inner ring vertically. The inner ring of the upper sealing cover 4 has a cylindrical hole with a diameter matching that of the cylinder piston rod 12. While tolerances are allowed for this dimensional consistency, they are typically around 0.02 mm. This provides better guidance and support for the cylinder piston rod 12. Similarly, the bottom sealing cover plate 3 is an annular plate with the cylinder piston rod 12 passing through its inner ring vertically. The inner ring diameter of the bottom sealing cover plate 3 also matches that of the cylinder piston rod 12.

[0040] The above design ensures that the cylinder can operate normally without any issues when it is in a pneumatic state, and will automatically lock itself in case of a gas shortage, and can be reset and reused, making it highly practical.

[0041] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A self-locking cylinder structure for air cut-off, characterized in that, The cylinder body includes a cylinder body and a self-locking assembly for self-locking when the cylinder body is cut off. The cylinder body includes a cylinder body (11) and a cylinder piston rod (12) extending upward from the cylinder body (11). The self-locking assembly includes a self-locking cylinder body (21) fixed on the upper side of the cylinder body (11) for the cylinder piston rod (12) to pass through upward, and a self-locking limiting annular surrounding cylinder (22) provided in the self-locking cylinder body (21) surrounding the cylinder piston rod (12) and used to lock the cylinder piston rod (12) when the air is cut off and release the cylinder piston rod (12) when the air is supplied. The self-locking limiting annular surrounding cylinder (22) can swing up and down.

2. The self-locking cylinder structure according to claim 1, characterized in that, The self-locking cylinder body (21) has a self-locking channel (211) and a supporting inner channel (212) that are connected vertically. A bottom sealing plate (3) is embedded in the supporting inner channel (212) to block the lower outlet of the self-locking channel (211). The lower side of the bottom sealing plate (3) abuts against the upper side of the cylinder body (11) and the bottom sealing plate (3) allows the cylinder piston rod (12) to pass through. The self-locking limiting annular surrounding cylinder (22) is located in the self-locking channel (211) and an upper sealing cover (4) is provided in the self-locking channel (211) above the self-locking limiting annular surrounding cylinder (22). The upper sealing cover (4) allows the cylinder piston rod (12) to pass through. The bottom sealing plate (3) and the self-locking limiting annular surrounding cylinder (212) are connected vertically. 2) A lifting spring (51) is provided between the self-locking limiting ring-shaped surrounding cylinder (22) and is in an upright position. The part of the self-locking channel (211) between the lower side of the upper sealing cover (4) and the upper side of the self-locking limiting ring-shaped surrounding cylinder (22) is used to form an air chamber (2110) to flatten the self-locking limiting ring-shaped surrounding cylinder (22) and then release the cylinder piston rod (12). A fulcrum shaft (52) is fixed on the upper side of the self-locking limiting ring-shaped surrounding cylinder (22) as the fulcrum when the self-locking limiting ring-shaped surrounding cylinder (22) swings. The top of the fulcrum shaft (52) abuts against the lower side of the upper sealing cover (4). The fulcrum shaft (52) and the lifting spring (51) are respectively on both sides of the cylinder piston rod (12).

3. The self-locking cylinder structure for air cut-off as described in claim 2, characterized in that, The self-locking cylinder (21) has an air inlet (2100) on its cylinder wall that communicates with the air filling chamber (2110).

4. The self-locking cylinder structure according to claim 2, characterized in that, The outer wall of the self-locking limiting annular surrounding cylinder (22) forms a swing guide arc surface (2200) that is arched downwards and tilts to the side. The fulcrum shaft (52) and the swing guide arc surface (2200) are on the same side of the cylinder piston rod (12).

5. The self-locking cylinder structure according to claim 2, characterized in that, The self-locking limiting annular surrounding cylinder (22) has a positioning groove (510) extending from the bottom upward for the lifting spring (51) to be inserted, and the lower side of the lifting spring (51) abuts against the bottom cover plate (3).

6. The self-locking cylinder structure according to claim 2, characterized in that, An annular upper sealing groove (401) is provided on the outer wall of the upper sealing cover (4). An upper sealing ring (4011) is embedded in the upper sealing groove (401) and abuts against the wall of the self-locking channel (211) and seals the inflation chamber (2110) on the upper side. An annular lower sealing groove (2201) is provided on the outer wall of the self-locking limiting annular surrounding cylinder (22). A lower sealing ring (22011) is embedded in the lower sealing groove (2201) and abuts against the wall of the self-locking channel (211) and seals the inflation chamber (2110) on the lower side.

7. The self-locking cylinder structure according to claim 6, characterized in that, The side of the self-locking limiting annular surrounding cylinder (22) is fixed with a reset plate (6) located below the lower sealing ring (22011) for the self-locking limiting annular surrounding cylinder (22) to swing and deflect downwards and reset. The reset plate (6) extends out of the self-locking cylinder body (21) from the side. The reset plate (6) and the lifting spring (51) are on the same side of the cylinder piston rod (12). The cylinder wall of the self-locking cylinder body (21) is provided with a reset port (61) that is open inside and out and allows the reset plate (6) to pass through and be pushed downwards.

8. The self-locking cylinder structure according to claim 2, characterized in that, There is a gap between the outermost part of the self-locking limiting annular surrounding cylinder (22) with the wall of the self-locking channel (211) and a gap between the innermost part of the inner wall of the self-locking limiting annular surrounding cylinder (22) and the cylinder piston rod (12).

9. The self-locking cylinder structure for air cut-off as described in claim 2, characterized in that, The upper sealing cover (4) has an annular structure and the inner ring allows the cylinder piston rod (12) to pass through vertically. The inner ring of the upper sealing cover (4) is a cylindrical hole with the same diameter as the cylinder piston rod (12).

10. The self-locking cylinder structure according to claim 9, characterized in that, The bottom cover plate (3) is an annular plate with the cylinder piston rod (12) passing through its inner ring. The inner ring diameter of the bottom cover plate (3) is the same as the diameter of the cylinder piston rod (12).

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