A continuous inoculator

Abstract

The invention discloses a continuous inoculator, comprising an outer cylinder, wherein a liquid injection cylinder, a gas injection cylinder and a two-position four-way valve are arranged in the outer cylinder, a liquid injection piston and a liquid injection piston rod fixed to the liquid injection piston are arranged in the liquid injection cylinder, a gas injection piston and a gas injection piston rod fixed to the gas injection piston are arranged in the gas injection cylinder, an outlet of the liquid injection cylinder is communicated with a first inlet of the two-position four-way valve, an outlet of the gas injection cylinder is communicated with a second inlet of the two-position four-way valve, a needle is arranged at the end of the outer cylinder, the needle is communicated with the first outlet of the two-position four-way valve, a liquid storage chamber communicated with the liquid injection cylinder is arranged outside the outer cylinder, the second outlet of the two-position four-way valve is communicated with the liquid storage chamber, the two-position four-way valve keeps the liquid injection cylinder and the needle in a normally connected state, a switching switch for switching the two-position four-way valve is arranged on the gas injection piston rod, and an end plate for driving the gas injection piston to compress the gas injection cylinder and acting on the switching switch is arranged on the liquid injection piston rod. The invention aims to eliminate the residual amount at the needle position during injection, thereby reducing the infection probability of silkworms.

Description

Technical Field

[0001] The invention belongs to the technical field of biomedicine, and in particular relates to a continuous inoculator. Background Art

[0002] At present, cosmetic raw materials need to be prepared by extraction from silkworms, and silkworms need to be vaccinated during the cultivation process to improve the survival rate of silkworms. The traditional vaccination method of silkworms usually uses a simple syringe, draws a certain amount of vaccine each time, and injects the vaccine into the body of the silkworm through the syringe. The amount of vaccine manually extracted is difficult to accurately control, and the manual injection vaccination speed is slow and the vaccination efficiency is low. In order to improve the vaccination efficiency, as shown in Chinese Patent Publication No.: CN209964822U, a special syringe for subcutaneous inoculation of silkworm pupae is disclosed, including a fixed barrel, a material box, a needle tube, an injection tube and a grip, the material box is fixedly installed on the top of the fixed barrel, the grip is fixedly installed on the bottom of the fixed barrel, the injection tube is arranged on the inside of the fixed barrel, the right end of the needle tube is connected to the injection tube, a push block is arranged on the left side of the bottom of the injection tube, a trigger is arranged on the right side of the corresponding push block in the fixed barrel, and the upper left end of the trigger is fitted with the push block, a feed inlet is arranged on the top of the material box, and the bottom of the material box is connected to the injection tube through an infusion tube, a discharge check valve is arranged on the left side of the infusion tube, and an injection check valve is arranged on the left side of the injection tube. However, when such a syringe is used, after each injection, the vaccine at the needle tip is likely to remain outside the silkworm's epidermis, causing the silkworm to be infected and reducing the silkworm's survival rate. Summary of the invention

[0003] In order to overcome the disadvantage of the prior art that the silkworms are easily infected due to residual vaccine in the needle when the syringe is used for subcutaneous injection, the present invention provides a continuous inoculator that can eliminate the residual vaccine in the needle during injection, thereby reducing the chance of infection of the silkworms.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A continuous inoculator comprises an outer cylinder, wherein a liquid injection cylinder, an air injection cylinder and a two-position four-way valve are arranged in the outer cylinder, a liquid injection piston and a liquid injection piston rod fixed to the liquid injection piston are arranged in the liquid injection cylinder, an air injection piston and an air injection piston rod fixed to the air injection piston are arranged in the air injection cylinder, an outlet of the liquid injection cylinder is communicated with a first inlet of the two-position four-way valve, and an outlet of the air injection cylinder is communicated with a second inlet of the two-position four-way valve, a needle is arranged at an end of the outer cylinder, and the needle is communicated with the first outlet of the two-position four-way valve, a liquid storage chamber communicated with the liquid injection cylinder is arranged outside the outer cylinder, the second outlet of the two-position four-way valve is communicated with the liquid storage chamber, the two-position four-way valve keeps the liquid injection cylinder and the needle in a normally connected state, a switching switch for switching the two-position four-way valve is arranged on the air injection piston rod, an end plate for driving the air injection piston to compress the air injection cylinder and acting on the switching switch is arranged on the liquid injection piston rod, and when the switching switch is triggered, the end plate acts on the two-position four-way valve to communicate the air injection cylinder with the needle and the liquid injection cylinder with the liquid storage chamber. When the end plate pushes the injection piston rod, driving the injection piston to compress the injection cylinder, the injection liquid passes through the first outlet of the two-position four-way valve and is injected from the needle into the subcutaneous part of the silkworm. When the injection piston moves to the end of its stroke, the end plate drives the gas injection piston to move and switches the connection state of the two-position four-way valve through the switch, so that the needle is connected to the gas injection cylinder, and a section of air is pressed into the needle, so that all the residual injection liquid in the needle is injected into the silkworm, thereby preventing the residual injection liquid in the needle from contaminating the silkworm epidermis, effectively preventing the silkworm from being infected, and improving the survival rate of the silkworm.

[0006] Preferably, the liquid injection cylinder and the gas injection cylinder are arranged side by side in the outer cylinder, the liquid injection piston rod and the gas injection piston rod are parallel to the axial direction of the outer cylinder, the end plate is provided with a through hole for the gas injection piston rod to pass through, and a liquid injection return spring is provided between the end plate and the liquid injection cylinder. The liquid injection piston rod and the gas injection piston rod are arranged in parallel, so that the end plate on the liquid injection piston rod can push the gas injection piston rod forward synchronously, and the relative positions of the two remain stable, which is conducive to smoothly pressing air into the needle to drain the remaining liquid in the needle. The liquid injection return spring can draw the injection liquid in the liquid storage chamber into the liquid injection cylinder during the return process of the liquid injection piston and the liquid injection piston rod.

[0007] Preferably, a support plate is fixed to the middle of the gas injection piston rod, the switch is arranged on the support plate, and a gas injection return spring is arranged between the support plate and the gas injection cylinder. When the gas injection piston and the gas injection piston rod move into the gas injection cylinder, the support plate compresses the gas injection return spring. When the external force is eliminated, the gas injection return spring will drive the gas injection piston and the gas injection piston rod to reset, and automatically draw air into the gas injection cylinder.

[0008] Preferably, a first one-way valve is provided between the outlet of the gas injection cylinder and the second inlet of the two-position four-way valve, the outlet of the gas injection cylinder is in one-way communication with the second inlet of the two-position four-way valve, an air intake filter is provided outside the outer cylinder, a second one-way valve is provided between the air intake filter and the inlet of the gas injection cylinder, the air intake filter is in one-way communication with the inlet of the gas injection cylinder. In this way, when the gas injection cylinder is compressed, air will be injected into the needle in one direction, and when the gas injection piston is reset, air will enter the gas injection cylinder in one direction through the air intake filter.

[0009] Preferably, a third one-way valve is provided between the outlet of the injection cylinder and the first inlet of the two-position four-way valve, the outlet of the injection cylinder is in one-way communication with the first inlet of the two-position four-way valve, a fourth one-way valve is provided between the outlet of the liquid storage chamber and the inlet of the injection cylinder, the outlet of the liquid storage chamber is in one-way communication with the inlet of the injection cylinder, a fifth one-way valve is provided between the second outlet of the two-position four-way valve and the liquid storage chamber, the second outlet of the two-position four-way valve is in one-way communication with the liquid storage chamber. In this way, when the injection cylinder is pressurized, the injection liquid flows unidirectionally into the needle for injection, and when the two-position four-way valve is switched, the injection liquid flows unidirectionally back into the liquid storage chamber through the second outlet. When the injection piston is restored, the injection liquid in the liquid storage chamber flows unidirectionally into the injection cylinder to achieve the replenishment of the injection liquid.

[0010] Preferably, a first through slot along the axial direction of the outer cylinder is provided on one side of the outer cylinder close to the injection cylinder, a slidingly matched injection adjustment block is provided in the first through slot, the injection adjustment block limits the movement of the end plate, the outer wall of the outer cylinder is provided with a first slide rail arranged parallel to the first through slot, the injection adjustment block is screwed and fixed to the first slide rail. By adjusting the movement of the end plate through the injection adjustment block, the injection volume of the injection liquid can be adjusted.

[0011] Preferably, a second through slot along the axial direction of the outer cylinder is provided on one side of the outer cylinder close to the gas injection cylinder, a slidably matched gas injection adjustment block is provided in the second through slot, the gas injection adjustment block limits the moving stroke of the support plate, the outer wall of the outer cylinder is provided with a second slide rail arranged parallel to the second through slot, the gas injection adjustment block is screwed and fixed to the second slide rail. By adjusting the moving stroke of the support plate through the gas injection adjustment block, the injection amount of air can be adjusted.

[0012] Preferably, a cylinder is disposed outside the end plate, and the push rod end of the cylinder acts on the end plate to drive the injection piston to compress the injection cylinder. The external cylinder pushes the injection piston and the gas injection piston to move, thereby reducing the labor intensity of the operator.

[0013] The beneficial effects of the present invention are: (1) when the injection process of the injection liquid is close to the end, part of the compressed air is injected into the needle to completely drain the remaining liquid in the needle to avoid residue, thereby preventing the residual injection liquid from infecting the silkworm; (2) the two-position four-way valve is switched by switching the switch, and the air is quickly switched at the end of the injection stroke; (3) after each injection is completed and reset, the injection liquid and air are automatically filled to improve the injection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the present invention;

[0015] Figure 2 It is a top view schematic diagram of the internal structure of the present invention;

[0016] Figure 3 It is the pipeline principle diagram of the present invention;

[0017] Figure 4 yes Figure 1 Schematic diagram of the internal structure;

[0018] Figure 5 yes Figure 1 Schematic diagram of the internal structure on the other side.

[0019] In the figure: outer tube 1, flange 1a, first through groove 1b, second through groove 1c, first slide rail 101, second slide rail 102, needle 2, air intake filter 3, liquid storage chamber 4, injection adjustment block 5, cylinder 6, injection piston rod 7, end plate 71, through hole 71a, injection return spring 8, injection piston 9, injection tube 10, third one-way valve 11, two-position four-way valve 12, first inlet 12a, second outlet 12b, first outlet 12c, second inlet 12d, first one-way valve 13, gas injection tube 14, gas injection piston 15, gas injection return spring 16, switching switch 17, gas injection adjustment block 18, gas injection piston rod 19, support plate 191, second one-way valve 20, fourth one-way valve 21, fifth one-way valve 22. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0021] like Figure 1 In the embodiment shown, a continuous inoculator includes an outer barrel 1, one end of which is provided with a needle 2, and the other end of the outer barrel 1 is open, and the open end is provided with a flange 1a for easy positioning. Figure 2As shown, a liquid injection cylinder 10, a gas injection cylinder 14 and a two-position four-way valve 12 are arranged in the outer cylinder 1. The liquid injection cylinder 10 and the gas injection cylinder 14 are arranged side by side in the outer cylinder 1. The liquid injection cylinder 10 is provided with a liquid injection piston 9 and a liquid injection piston rod 7 fixed to the liquid injection piston 9. The gas injection cylinder 14 is provided with a gas injection piston 15 and a gas injection piston rod 19 fixed to the gas injection piston 15. The liquid injection piston rod 7 and the gas injection piston rod 19 are parallel to the axial direction of the outer cylinder 1. The liquid injection piston rod 7 is provided with an end plate 71 for driving the gas injection piston 15 to compress the gas injection cylinder 14. The end plate 71 is provided with a through hole 71a for the gas injection piston rod 19 to pass through. A liquid injection return spring 8 is provided between the end plate 71 and the liquid injection cylinder 10. A support plate 191 is fixed to the middle of the gas injection piston rod 19, and a gas injection return spring 16 is provided between the support plate 191 and the gas injection cylinder 14. The stroke of the gas injection piston 15 is usually smaller than that of the liquid injection piston 9. The end plate 71 is located outside the support plate 191. In this embodiment, the end plate 71 and the support plate 191 are arranged in parallel. When the end plate 71 pushes the liquid injection piston 9 to move close to the end of the stroke, the end plate 71 will act on the support plate 191. The outer side of the end plate 71 is provided with a cylinder 6, and the push rod end of the cylinder 6 acts on the end plate 71 to drive the liquid injection piston 9 to compress the liquid injection cylinder 10.

[0022] like Figure 2 As shown, the two-position four-way valve 12 is located inside the outer cylinder 1, the outlet of the liquid injection cylinder 10 is located at the end of the liquid injection cylinder 10, and the outlet of the gas injection cylinder 14 is located at the end of the gas injection cylinder 14. Figure 3 As shown, the outlet of the liquid injection cylinder 10 is connected to the first inlet 12a of the two-position four-way valve 12, the outlet of the gas injection cylinder 14 is connected to the second inlet 12d of the two-position four-way valve 12, and the needle 2 is connected to the first outlet 12c of the two-position four-way valve 12. Figure 4 As shown, the outer tube 1 is provided with a liquid storage chamber 4 connected with the injection cylinder 10, and the second outlet 12b of the two-position four-way valve 12 is connected with the liquid storage chamber 4. The two-position four-way valve 12 keeps the injection cylinder 10 and the needle 2 in a normally connected state, and a switch 17 for switching the two-position four-way valve 12 is provided on the support plate 191 of the gas injection piston rod 19. When the end plate 71 acts on the switch 17 to be triggered, the two-position four-way valve 12 connects the gas injection cylinder 14 with the needle 2 and the injection cylinder 10 with the liquid storage chamber 4.

[0023] like Figure 2 , Figure 3 As shown, a first one-way valve 13 is provided between the outlet of the gas injection cylinder 14 and the second inlet 12d of the two-position four-way valve 12, and the outlet of the gas injection cylinder 14 is one-way connected to the second inlet 12d of the two-position four-way valve 12. Figure 4As shown, an air intake filter 3 is provided on the outside of the outer cylinder 1, and a second one-way valve 20 is provided between the air intake filter 3 and the inlet of the gas injection cylinder 14, and the air intake filter 3 is in one-way communication with the inlet of the gas injection cylinder 14. A third one-way valve 11 is provided between the outlet of the liquid injection cylinder 10 and the first inlet 12a of the two-position four-way valve 12, and the outlet of the liquid injection cylinder 10 is in one-way communication with the first inlet 12a of the two-position four-way valve 12, a fourth one-way valve 21 is provided between the outlet of the liquid storage chamber 4 and the inlet of the liquid injection cylinder 10, and the outlet of the liquid storage chamber 4 is in one-way communication with the inlet of the liquid injection cylinder 10, a fifth one-way valve 22 is provided between the second outlet 12b of the two-position four-way valve 12 and the liquid storage chamber 4, and the second outlet 12b of the two-position four-way valve 12 is in one-way communication with the liquid storage chamber 4.

[0024] like Figure 2 , Figure 5 As shown, a first through slot 1b is provided along the axial direction of the outer cylinder 1 on one side of the outer cylinder 1 close to the liquid injection cylinder 10, a liquid injection adjustment block 5 is provided in the first through slot 1b, and the liquid injection adjustment block 5 limits the movement of the end plate 71. A first slide rail 101 is provided on the outer wall of the outer cylinder 1 in parallel with the first through slot 1b, and the liquid injection adjustment block 5 is screwed and fixed to the first slide rail 101. A second through slot 1c is provided along the axial direction of the outer cylinder 1 on one side of the outer cylinder 1 close to the gas injection cylinder 14, and a gas injection adjustment block 18 is provided in the second through slot 1c in a sliding manner, and the gas injection adjustment block 18 limits the movement of the support plate 191. A second slide rail 102 is provided on the outer wall of the outer cylinder 1 in parallel with the second through slot 1c, and the gas injection adjustment block 18 is screwed and fixed to the second slide rail 102.

[0025] During actual operation, in the initial state, the end plate 71 is not subjected to the force of the cylinder 6, and the end plate 71 will be maintained at a position against the liquid injection adjustment block 5 under the action of the liquid injection return spring 8. At the same time, the support plate 191 is also maintained at a position against the gas injection adjustment block 18 under the action of the gas injection return spring 16. By adjusting the positions of the liquid injection adjustment block 5 and the gas injection adjustment block 18, the strokes of the liquid injection piston 9 and the gas injection piston 15 are changed, thereby adjusting the liquid injection amount and the gas injection amount, so as to facilitate debugging and improve adaptability. When the cylinder 6 is started, the piston rod of the cylinder 6 pushes out and acts on the end plate 71, and the end plate 71 moves toward the inside of the outer tube 1. At this time, the second inlet 12d and the first outlet 12c of the two-position four-way valve 12 are connected, and the liquid injection piston 9 discharges the injection fluid in the liquid injection cylinder 10 into the needle 2, while the first inlet 12a and the second outlet 12b of the two-position four-way valve 12 are in the cut-off state. When the end plate 71 continues to move into the outer tube 1 until the end plate 71 contacts the switch 17 on the support plate 191, the switch 17 will change the state of the two-position four-way valve 12, so that the first inlet 12a is connected to the first outlet 12c, and the second inlet 12d is connected to the second outlet 12b. When the end plate 71 drives the support plate 191 to continue to move, the injection piston 9 presses the remaining injection liquid in the injection cylinder 10 back into the liquid storage chamber 4, and the gas injection piston 15 injects the air in the gas injection cylinder 14 into the needle 2, and completely empties the remaining injection liquid in the needle 2 to prevent the injection liquid from remaining in the needle 2. When the piston rod of the cylinder 6 moves in the opposite direction, the injection piston 9 returns under the action of the injection return spring 8, and the injection piston 9 generates negative pressure in the injection cylinder 10, and the injection liquid in the liquid storage chamber 4 is drawn into the injection cylinder 10 to achieve the filling of the injection liquid. At the same time, the gas injection piston 15 is restored under the action of the gas injection return spring 16, and the gas injection piston 15 generates negative pressure in the gas injection cylinder 14, and draws air from the outside through the air intake filter 3 into the gas injection cylinder 14 to achieve air filling. The intake, exhaust, liquid intake, and liquid discharge are all connected in one direction, which can ensure the smooth flow of injection liquid and air and avoid the phenomenon of backflow. The end plate 71 and the support plate 191 are also separated during the recovery process of the liquid injection piston 9 and the gas injection piston 15, and the switching switch 17 bounces back to the original position, so that the two-position four-way valve 12 is reset to the initial state to facilitate the next injection process.

Claims

1. A continuous inoculator, characterized in that: The invention comprises an outer cylinder (1), wherein a liquid injection cylinder (10), a gas injection cylinder (14) and a two-position four-way valve (12) are arranged inside the outer cylinder (1), wherein a liquid injection piston (9) and a liquid injection piston rod (7) fixed to the liquid injection piston (9) are arranged in the liquid injection cylinder (10), and a gas injection piston (15) and a gas injection piston rod (19) fixed to the gas injection piston (15) are arranged in the gas injection cylinder (14), wherein the outlet of the liquid injection cylinder (10) is connected to a first inlet (12a) of the two-position four-way valve (12), and the outlet of the gas injection cylinder (14) is connected to a second inlet (12d) of the two-position four-way valve (12), and a needle (2) is arranged at the end of the outer cylinder (1), and the needle (2) is connected to the first outlet (12c) of the two-position four-way valve (12). The outer tube (1) is provided with a liquid storage chamber (4) in communication with the liquid injection cylinder (10) on the outside, the second outlet (12b) of the two-position four-way valve (12) is in communication with the liquid storage chamber (4), the two-position four-way valve (12) enables the liquid injection cylinder (10) and the needle (2) to maintain a normally connected state, the gas injection piston rod (19) is provided with a switching switch (17) for switching the two-position four-way valve (12), the liquid injection piston rod (7) is provided with an end plate (71) for driving the gas injection piston (15) to compress the gas injection cylinder (14) and act on the switching switch (17), the end plate (71) acts on the two-position four-way valve (12) when the switching switch (17) is triggered, so that the gas injection cylinder (14) and the needle (2) are connected, and the liquid injection cylinder (10) and the liquid storage chamber (4) are connected. The liquid injection cylinder (10) and the gas injection cylinder (14) are arranged in parallel in the outer cylinder (1); the liquid injection piston rod (7) and the gas injection piston rod (19) are parallel to the axial direction of the outer cylinder (1); the end plate (71) is provided with a through hole (71a) for the gas injection piston rod (19) to pass through; a liquid injection return spring (8) is provided between the end plate (71) and the liquid injection cylinder (10); a support plate (191) is fixed to the middle of the gas injection piston rod (19); the switching switch (17) is arranged on the support plate (191); a gas injection return spring (16) is provided between the support plate (191) and the gas injection cylinder (14); a cylinder (6) is provided on the outer side of the end plate (71); the push rod end of the cylinder (6) acts on the end plate ( The piston (71) drives the injection piston (9) to compress the injection cylinder (10). When the cylinder (6) is started, the piston rod of the cylinder (6) pushes out to act on the end plate (71), and the end plate (71) moves toward the inside of the outer cylinder (1). At this time, the second inlet (12d) and the first outlet (12c) of the two-position four-way valve (12) are connected, and the injection piston (9) discharges the injection fluid in the injection cylinder (10) into the needle (2), while the first inlet (12a) and the second outlet (12b) of the two-position four-way valve (12) are in the cut-off state. When the end plate (71) continues to move into the outer cylinder (1) until the end plate (71) contacts the switching switch (17) on the support plate (191), the switching switch (17) changes the state of the two-position four-way valve (12).The first inlet (12a) is connected to the first outlet (12c), and the second inlet (12d) is connected to the second outlet (12b). When the end plate (71) drives the support plate (191) to continue to move, the injection piston (9) presses the remaining injection fluid in the injection cylinder (10) back into the liquid storage chamber (4). At the same time, the gas injection piston (15) injects the air in the gas injection cylinder (14) into the needle (2), and completely empties the remaining injection fluid in the needle (2), thereby preventing the injection fluid from remaining in the needle (2). When the cylinder (6) When the piston rod moves in the reverse direction, the liquid injection piston (9) returns under the action of the liquid injection return spring (8), and the liquid injection piston (9) generates negative pressure in the liquid injection cylinder (10), and the injection liquid in the liquid storage chamber (4) is drawn into the liquid injection cylinder (10), thereby achieving the filling of the injection liquid. At the same time, the gas injection piston (15) returns under the action of the gas injection return spring (16), and the gas injection piston (15) generates negative pressure in the gas injection cylinder (14), and air is drawn from the outside through the air intake filter (3) into the gas injection cylinder (14), thereby achieving the filling of air.

2. A continuous inoculator according to claim 1, characterized in that: A first one-way valve (13) is provided between the outlet of the gas injection cylinder (14) and the second inlet (12d) of the two-position four-way valve (12), and the outlet of the gas injection cylinder (14) is one-way connected to the second inlet (12d) of the two-position four-way valve (12). An air intake filter (3) is provided outside the outer cylinder (1), and a second one-way valve (20) is provided between the air intake filter (3) and the inlet of the gas injection cylinder (14), and the air intake filter (3) is one-way connected to the inlet of the gas injection cylinder (14).

3. A continuous inoculator according to claim 1, characterized in that: A third one-way valve (11) is provided between the outlet of the injection cylinder (10) and the first inlet (12a) of the two-position four-way valve (12), and the outlet of the injection cylinder (10) is one-way connected to the first inlet (12a) of the two-position four-way valve (12). A fourth one-way valve (21) is provided between the outlet of the liquid storage chamber (4) and the inlet of the injection cylinder (10), and the outlet of the liquid storage chamber (4) is one-way connected to the inlet of the injection cylinder (10). A fifth one-way valve (22) is provided between the second outlet (12b) of the two-position four-way valve (12) and the liquid storage chamber (4), and the second outlet (12b) of the two-position four-way valve (12) is one-way connected to the liquid storage chamber (4).

4. A continuous inoculator according to claim 1, characterized in that: A first through groove (1b) is provided on a side of the outer cylinder (1) close to the liquid injection cylinder (10) along the axial direction of the outer cylinder (1); a liquid injection adjustment block (5) is provided in the first through groove (1b) for sliding fit; the liquid injection adjustment block (5) limits the movement stroke of the end plate (71); a first slide rail (101) is provided on the outer wall of the outer cylinder (1) and is arranged parallel to the first through groove (1b); the liquid injection adjustment block (5) is fixed to the first slide rail (101) by screws.

5. A continuous inoculator according to claim 1, characterized in that: A second through groove (1c) is provided on one side of the outer cylinder (1) close to the gas injection cylinder (14) along the axial direction of the outer cylinder (1); a slidably fitted gas injection adjustment block (18) is provided in the second through groove (1c); the gas injection adjustment block (18) limits the movement stroke of the support plate (191); a second slide rail (102) is provided on the outer wall of the outer cylinder (1) and is arranged parallel to the second through groove (1c); the gas injection adjustment block (18) is fixed to the second slide rail (102) by screws.

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