CN111904856A

CN111904856A - Medical medicine dispenser

Info

Publication number: CN111904856A
Application number: CN202010783042.2A
Authority: CN
Inventors: 胡欣欣; 胡宇奔
Original assignee: Zhejiang Lingyang Medical Apparatus Co ltd
Current assignee: Zhejiang Lingyang Medical Apparatus Co ltd
Priority date: 2020-08-06
Filing date: 2020-08-06
Publication date: 2020-11-10
Anticipated expiration: 2040-08-06
Also published as: CN111904856B

Abstract

The invention provides a medical medicine dispenser. The liquid outlet is positioned at one end of the needle tube, the piston is provided with a first annular air bag sheet, the first annular air bag sheet is provided with a first inflatable cavity, and the piston is internally provided with a first air passage; the piston is provided with a second annular air bag sheet, the second annular air bag sheet is provided with a second inflatable cavity, and the piston is internally provided with a second air passage; a first inflation channel is arranged in the needle core, one end of the first inflation channel is communicated with the first air passage, and a first inflation rod is arranged on the first inflation channel; a second inflation channel is arranged in the needle core, one end of the second inflation channel is communicated with the second air passage, and a second inflation rod is arranged on the second inflation channel; the needle core is provided with a driving sliding groove, a driving sliding block is arranged in the driving sliding groove, and the end part of the driving sliding block is provided with a wedge-shaped surface. According to different sealing and pumping requirements under different medical care environments, the effective contact area between the piston and the inner cylinder wall of the needle cylinder is adjusted, and the defect that the hands of medical care personnel are sore after the use is further overcome.

Description

Medical medicine dispenser

Technical Field

The invention relates to medical instruments, in particular to a medical medicine dispenser.

Background

Medical apparatus that uses under the medical environment, relatively common is medical dispensing device, and its structure is CN 201631788U's the chinese utility model patent dispensing device as bulletin number, including syringe needle, needle tubing, piston, nook closing member, the syringe needle is installed in the tip position of needle tubing, is equipped with outside turn-ups at the tip that the needle tubing deviates from the syringe needle, and the piston is installed in the needle tubing, and the reciprocating piston that promotes of nook closing member, the injection in the needle tubing can be extruded, or the outer injection of needle tubing can be by the suction.

When the medical care personnel use, the hands exert reverse action on the needle tube and the needle core respectively, and the side wall of the piston and the inner tube wall of the needle tube generate sealing sliding.

The effective contact area between the traditional piston and the inner tube wall of the needle tube is fixed, namely the force required by medical staff to pull the needle core is fixed, when the medicine dispenser is required to have large drawing force on liquid medicine, the fixed sealing drawing force generated by the fixed effective contact area between the piston and the inner tube wall of the needle tube possibly cannot meet the required drawing force requirement; when the medicine dispenser is not needed to generate large drawing force to liquid medicine, the sealing drawing force generated by the fixation of the effective contact area between the piston and the inner pipe wall of the needle pipe is fixed, and the hands of medical workers can generate ache after the medical workers operate for a long time.

Disclosure of Invention

In view of the above, the present invention is to provide a medical dispensing device, which can adjust the effective contact area between the piston and the inner cylinder wall of the syringe according to different sealing and pumping requirements under different medical environments, so as to help alleviate the hand pain of medical staff after use.

In order to solve the technical problems, the technical scheme of the invention is as follows:

a medical medicine dispensing device comprises a liquid outlet, a needle tube, a piston and a needle core, wherein the liquid outlet is positioned at one end of the needle tube, the piston is arranged at the end part of the needle core and positioned in the needle tube,

the first annular air bag sheet is arranged on the circumferential outer side wall of the piston, a first inflation cavity is formed between the first annular air bag sheet and the outer side wall of the piston, and a first air passage communicated with the first inflation cavity is arranged in the piston;

an annular air bag sheet II is arranged on the circumferential outer side wall of the piston, an inflation cavity II is formed between the annular air bag sheet II and the outer side wall of the piston, and an air passage II communicated with the inflation cavity II is arranged in the piston;

a first inflation channel is arranged in the needle core, one end of the first inflation channel is communicated with the first air passage, and an inflation rod I is arranged in the other end of the first inflation channel in a sealing and sliding manner;

a second inflation channel is arranged in the needle core, one end of the second inflation channel is communicated with a second air passage, and a second inflation rod is arranged in the other end of the second inflation channel in a sealing and sliding manner;

be equipped with the drive spout on the stylet, aerify a pole tip, aerify two tip of pole and all be located the drive spout, be equipped with drive slider in the drive spout, drive slider tip is equipped with the wedge face, the wedge face can offset in proper order with aerifing a pole one rod end, aerifing two rod ends of pole, and then drive and aerify pole one and slide along first inflation channel, drive and aerify pole two and slide along the second inflation channel.

According to the technical scheme, firstly, when the medicine dispenser is required to be used, the piston and the needle tube can be placed in the needle tube, and the piston can be easily plugged into the needle tube because the annular air bag sheet I and the annular air bag sheet II are not expanded at the moment;

secondly, the driving slide block is pushed, a wedge-shaped surface at the end part of the driving slide block firstly abuts against a first inflation rod, the first inflation rod slides along a first inflation channel, gas is filled into a first inflation cavity, an annular air bag sheet expands and deforms and abuts against the inner wall of the needle tube, at the moment, the needle core is pulled, the annular air bag sheet and the inner wall of the needle tube slide in a sealing mode for a while, the required push-pull force is relatively small, the effective contact area between the piston and the inner wall of the needle tube is relatively small, the maximum drawing force generated by the whole medicine dispensing device is relatively small, and the medicine dispensing device is suitable for being used in a medical environment with low requirement on the sealing drawing force;

thirdly, the driving slide block is continuously pushed, the wedge-shaped surface of the driving slide block continuously abuts against the second inflation rod, the second inflation rod slides along the second inflation channel, gas is filled in the second inflation cavity, the annular air bag sheet II expands and deforms and abuts against the inner pipe wall of the needle tube, at the moment, the needle core is pulled, the annular air bag sheet I and the annular air bag sheet II can simultaneously slide in a sealing mode with the inner pipe wall of the needle tube, the required push-pull force is relatively large, the effective contact area between the piston and the inner pipe wall of the needle tube is relatively large, the maximum suction force generated by the whole medicine dispensing device is relatively large, and the medicine dispensing device is suitable for being used in a medical environment with high requirement on sealing suction force;

by adopting the structure and the corresponding adjusting mode, the effective contact area between the piston and the inner cylinder wall of the needle cylinder can be adjusted according to different sealing pumping requirements under different medical care environments, and further the defect that the hands of medical care personnel are sore after use is favorably alleviated.

Preferably, the end part of the stylet is provided with a first insertion rod, the first insertion rod is inserted into the piston, the first insertion rod is provided with a first vent hole, and the first vent hole is communicated with the first inflation channel and the first air passage.

Through the technical scheme, firstly, the first vent hole on the first inserted rod is communicated with the first inflation channel and the first air passage, so that the finished gas can smoothly enter the first inflation cavity; secondly, the first inserted bar is inserted into the piston, so that the connecting points between the piston and the needle core are increased, and the connecting stability between the piston and the needle core is effectively improved.

Preferably, the end part of the stylet is provided with a second insertion rod, the second insertion rod is inserted into the piston, the second insertion rod is provided with a second vent hole, and the second vent hole is communicated with a second inflation channel and a second air passage.

Through the technical scheme, firstly, the second vent hole in the second inserted rod is communicated with the second inflation channel and the second air passage, so that the finished gas can smoothly enter the second inflation cavity; secondly, the second inserting rod is inserted into the piston, so that connecting points between the piston and the needle core are increased, and the connecting stability between the piston and the needle core is effectively improved.

Preferably, the circumferential outer side wall of the piston is also provided with a third annular air bag sheet, a third inflation cavity is formed between the third annular air bag sheet and the outer side wall of the piston, and a third air passage communicated with the third inflation cavity is formed in the piston;

a third inflation channel is arranged in the needle core, one end of the third inflation channel is communicated with the third air passage, and an inflation rod III is arranged in the other end of the third inflation channel in a sealing and sliding manner;

the wedge-shaped surface can offset with aerifing one rod end of pole, aerifing two rod ends of pole, three rod ends of pole of aerifing in proper order, and then drive and aerify the pole one and slide along first inflation channel, drive and aerify pole two and aerify the channel along the second and slide, drive and aerify pole three and slide along the third inflation channel.

According to the technical scheme, the driving slide block is continuously pushed again, the wedge-shaped surface of the driving slide block can continuously abut against the third inflation rod, the third inflation rod slides along the third inflation channel, gas is filled into the third inflation cavity, the third annular air sac sheet expands and deforms and abuts against the inner wall of the needle tube, at the moment, the needle core is pulled, the first annular air sac sheet, the second annular air sac sheet and the third annular air sac sheet can simultaneously slide in a sealing mode with the inner wall of the needle tube, the required push-pull force is relatively large, the effective contact area between the piston and the inner wall of the needle tube is relatively large, the maximum suction force generated by the whole medicine dispensing device is maximum, and the medicine dispensing device is suitable for being used in the medical care environment with the highest requirement on the sealing suction force.

Preferably, the end part of the stylet is provided with a third insertion rod, the third insertion rod is inserted into the piston, the third insertion rod is provided with a third vent hole, and the third vent hole is communicated with a third inflation channel and a third air passage.

Through the technical scheme, firstly, the third vent hole in the third inserted rod is communicated with the third inflation channel and the third air passage, so that the finished gas can smoothly enter the third inflation cavity; secondly, the third inserted link inserts in the piston, has increased the tie point between piston and the nook closing member, and then has effectively promoted the stability of being connected between piston and the nook closing member.

Preferably, sealing rings are arranged between the first inflation rod, the second inflation rod and the third inflation rod and between the corresponding first inflation channel, the corresponding second inflation channel and the corresponding third inflation channel.

Through the technical scheme, on one hand, the arrangement of the sealing ring can relatively fix the positions of the first inflation rod, the second inflation rod and the third inflation rod with the corresponding first inflation channel, the second inflation channel and the third inflation channel; on the other hand, when the first inflation rod, the second inflation rod and the third inflation rod move relative to the corresponding first inflation channel, the second inflation channel and the third inflation channel, the compression of the gas in the corresponding inflation channels is more stable.

Preferably, the end part, deviating from the liquid outlet, of the needle tube is provided with an outward flange, the flange is provided with a threaded hole in a penetrating manner, the threaded hole is internally connected with a driving screw rod, the end part, close to the needle core, of the driving screw rod is provided with a thorn piece, and the driving screw rod can drive the thorn piece to move into the needle tube.

Through the technical scheme, after the medicine dispenser is used, the driving screw rod can be rotated through the accessible, the puncturing sheet at the end part of the driving screw rod can move in the needle tube along with the driving screw rod, and when the needle core pulls the piston to the driving screw rod, the puncturing sheet can puncture the annular air bag sheet III, the annular air bag sheet II and the annular air bag sheet I one by one, so that the purpose of self-destruction is achieved, and the medical instrument is prevented from being used in a secondary violation manner.

Preferably, the cutting edge of the thorn piece is circular, and the plane of the cutting edge of the thorn piece is parallel to the sliding direction of the needle core.

Through above-mentioned technical scheme, because drive screw can drive the thorn piece and carry out the rotation in a circumferential direction, the blade shape of thorn piece sets up to circular, no matter what angle drive screw is rotatory, the blade homoenergetic of this thorn piece produces effectual destruction effect to annular gasbag piece three, annular gasbag piece two, annular gasbag piece one.

Preferably, the outer side wall of the needle core is provided with a limiting block, the outer side wall of the driving sliding block is provided with a plurality of limiting grooves, the limiting grooves are arranged along the sliding direction of the driving sliding block, and the end parts of the limiting block can be inserted into the limiting grooves in a one-to-one correspondence mode.

Through above-mentioned technical scheme, the stopper can be embedded into the spacing recess of different positions, and the actual use stability of whole medicine dispenser is promoted to the position of sliding at location drive slider place.

The technical effects of the invention are mainly reflected in the following aspects:

(1) selectively inflating the first inflation cavity, the second inflation cavity and the third inflation cavity to change the effective contact area between the piston and the inner pipe wall of the needle tube, so that the push-pull force for driving the piston to move is changed;

(2) the flanging is provided with a puncturing sheet structure, so that the annular air bag sheet III, the annular air bag sheet II and the annular air bag sheet I can be punctured.

Drawings

FIG. 1 is a schematic cross-sectional view of an embodiment;

FIG. 2 is an enlarged view of portion A of FIG. 1;

FIG. 3 is an enlarged view of portion B of FIG. 1;

FIG. 4 is an enlarged view of section C of FIG. 1;

fig. 5 is an enlarged view of a portion D of fig. 1.

Reference numerals: 1. a liquid outlet; 2. a needle tube; 3. a piston; 4. a needle core; 5. a first annular airbag sheet; 6. a first inflation cavity; 7. a first air passage; 8. a first inflation rod; 9. a first inflation channel; 10. inserting a first rod; 11. a first vent hole; 12. a second annular air bag sheet; 13. a second inflatable cavity; 14. an air passage II; 15. a second inflation rod; 16. a second inflation channel; 17. a second inserted link; 18. a second vent hole; 19. a third annular airbag sheet; 20. a third inflatable cavity; 21. an air passage III; 22. a third inflation channel; 23. a third inflation rod; 24. inserting a rod III; 25. a third vent hole; 26. a drive chute; 27. driving the slide block; 28. a wedge-shaped surface; 29. a seal ring; 30. flanging; 31. a threaded hole; 32. a drive screw; 33. pricking sheets; 34. a limiting block; 35. and a limiting groove.

Detailed Description

The following detailed description of the embodiments of the present invention is provided in order to make the technical solution of the present invention easier to understand and understand.

A medical medicine dispenser, see figure 1, comprises a needle tube 2, a piston 3 and a needle core 4, wherein one end of the needle tube 2 is provided with a liquid outlet 1, the other end of the needle tube 2 forms an opening, the piston 3 is arranged at the end position of the needle core 4, and the piston 3 and the needle core 4 are inserted into the needle tube 2 from the opening at the same time.

Referring to fig. 2, a first annular air bag sheet 5, a second annular air bag sheet 12 and a third annular air bag sheet 19 are arranged on the circumferential outer side wall of the piston 3, and the first annular air bag sheet 5, the second annular air bag sheet 12 and the third annular air bag sheet 19 are distributed along the direction departing from the liquid outlet 1.

Corresponding internal structures are arranged in the piston 3 and the needle core 4 aiming at the annular air bag sheet I5.

Referring to fig. 2 and 3, an inflation cavity one 6 is formed between the annular airbag piece one 5 and the outer side wall of the piston 3, and an air passage one 7 communicated with the inflation cavity one 6 is arranged in the piston 3. A first inflation channel 9 is arranged in the stylet 4, one end of the first inflation channel 9 is communicated with the first air passage 7, and an inflation rod I8 is arranged at the other end of the first inflation channel 9 in a sealing and sliding mode. The end part of the stylet 4 is provided with a first inserted link 10, the first inserted link 10 is inserted into the piston 3, the first inserted link 10 is provided with a first vent hole 11, and the first vent hole 11 is communicated with the first inflation channel 9 and the first air passage 7.

Corresponding internal structures are arranged in the piston 3 and the needle core 4 of the second annular air bag sheet 12.

Referring to fig. 2 and fig. 3, a second inflation cavity 13 is formed between the second annular airbag piece 12 and the outer side wall of the piston 3, and a second air passage 14 communicated with the second inflation cavity 13 is arranged in the piston 3. A second inflation channel 16 is arranged in the stylet 4, one end of the second inflation channel 16 is communicated with the second air passage 14, and a second inflation rod 15 is arranged in the other end of the second inflation channel 16 in a sealing and sliding mode. The end part of the stylet 4 is provided with a second inserted link 17, the second inserted link 17 is inserted into the piston 3, the second inserted link 17 is provided with a second vent hole 18, and the second vent hole 18 is communicated with a second inflation channel 16 and a second air passage 14.

For the third annular air bag sheet 19, the piston 3 and the needle core 4 are provided with corresponding internal structures.

Referring to fig. 2 and fig. 3, an inflation cavity three 20 is formed between the annular airbag piece three 19 and the outer side wall of the piston 3, and an air passage three 21 communicated with the inflation cavity three 20 is arranged in the piston 3. A third inflation channel 22 is arranged in the stylet 4, one end of the third inflation channel 22 is communicated with the air passage III 21, and an inflation rod III 23 is arranged at the other end of the third inflation channel 22 in a sealing and sliding manner. The end part of the needle core 4 is provided with a third inserted rod 24, the third inserted rod 24 is inserted into the piston 3, the third inserted rod 24 is provided with a third air vent 25, and the third air vent 25 is communicated with the third inflation channel 22 and the third air passage 21.

Referring to fig. 3, a driving sliding groove 26 is arranged on the stylet 4, the driving sliding groove 26 transversely penetrates through the stylet 4, and the end part of the first inflation rod 8, the end part of the second inflation rod 15 and the end part of the third inflation rod 23 are all positioned in the driving sliding groove 26.

Referring to fig. 3, a driving slide block 27 is arranged in the driving slide groove 26, a wedge-shaped surface 28 is arranged at the end of the driving slide block 27, and the wedge-shaped surface 28 can be sequentially abutted against the rod end of the first inflation rod 8, the rod end of the second inflation rod 15 and the rod end of the third inflation rod 23. In the process of gradually moving the driving slide block 27, the wedge-shaped surface 28 can push the first inflation rod 8, the second inflation rod 15 and the third inflation rod 23 to move towards the liquid outlet 1.

Referring to fig. 1 and 3, sealing rings 29 are arranged between the first inflation rod 8, the second inflation rod 15 and the third inflation rod 23 and the corresponding first inflation channel 9, the second inflation channel 16 and the third inflation channel 22.

In addition, referring to fig. 1 and 4, an outward flange 30 is disposed at an end of the needle tube 2 away from the liquid outlet 1, a threaded hole 31 is formed through the flange 30, a driving screw 32 is connected to the threaded hole 31 through a female thread, a barbed sheet 33 is disposed at an end of the driving screw 32 close to the stylet 4, and the driving screw 32 can drive the barbed sheet 33 to move into the needle tube 2.

Referring to fig. 4, the cutting edge of the barbed sheet 33 is circular, and the plane of the cutting edge of the barbed sheet 33 is parallel to the sliding direction of the stylet 4.

Referring to fig. 1 and 5, the outer side wall of the stylet 4 is provided with a limiting block 34, the outer side wall of the driving slide block 27 is provided with a plurality of limiting grooves 35, the limiting grooves 35 are arranged along the sliding direction of the driving slide block 27, and the end parts of the limiting block 34 can be inserted into the limiting grooves 35 in a one-to-one correspondence manner. The number of the limiting grooves 35 shown in this embodiment is three, and when the limiting blocks 34 are clamped in the corresponding limiting grooves 35, the wedge-shaped surface 28 can extrude the corresponding inflation rod to one side of the liquid outlet 1, and the corresponding annular airbag piece deforms and expands.

The practical use condition is as follows:

the first condition is as follows: when the sealing drawing force requirement inside the medicine dispenser is low, the driving slide block 27 is pushed, the wedge-shaped surface 28 at the end part of the driving slide block 27 extrudes the end part of the first inflation rod 8 in the first inflation channel 9, the first inflation rod 8 moves towards the liquid outlet 1 along the first inflation channel 9, the first inflation rod 8 with the sealing ring 29 extrudes air in the first inflation channel 9 to the first vent hole 11, the first air passage 7 and the first inflation cavity 6, the whole annular air sac piece 5 expands, and the annular air sac piece 5 abuts against the inner pipe wall of the needle pipe 2.

Case two: when the sealing drawing force inside the medicine dispenser is required to be moderate, the driving slide block 27 is continuously pushed, the first inflation channel 9 where the first inflation rod 8 is located is fixed in position under the extrusion action of the driving slide block 27, and the expansion degree of the annular airbag piece I5 is stable; in addition, the wedge-shaped surface 28 at the end of the driving slider 27 will also extrude the end of the second inflation rod 15, the second inflation rod moves toward the liquid outlet 1 along the second inflation channel 16, the second inflation rod 15 with the sealing ring 29 will extrude the air in the second inflation channel 16 into the second ventilation hole 18, the second air passage 14 and the second inflation cavity 13, the whole second annular air bag sheet 12 will expand, the second annular air bag sheet 12 will abut against the inner tube wall of the needle tube 2, and at this time, the first annular air bag sheet 5 and the second annular air bag sheet 12 will abut against the inner tube wall of the needle tube 2 at the same time.

Case three: when the sealing drawing force inside the medicine dispenser is high in requirement, the driving slide block 27 is continuously pushed again, under the extrusion action of the driving slide block 27, the first inflation channel 9 where the first inflation rod 8 is located is fixed in position, the expansion degree of the annular air bag sheet I5 is stable, the second inflation channel 16 where the second inflation rod 15 is located is fixed in position, and the expansion degree of the annular air bag sheet II 12 is stable; in addition, the wedge-shaped surface 28 at the end of the driving slider 27 will also extrude the end of the inflation rod three 23, the inflation rod three 23 will move toward the liquid outlet 1 along the third inflation channel 22, the inflation rod three 23 with the sealing ring 29 will extrude the air in the third inflation channel 22 to the third vent 25, the air passage three 21 and the inflation cavity three 20, the whole annular air bag piece three 19 will expand, the annular air bag piece three 19 will abut against the inner tube wall of the needle tube 2, and at this time, the annular air bag piece one 5, the annular air bag piece two 12 and the annular air bag piece three 19 will abut against the inner tube wall of the needle tube 2 at the same time.

Case four: after the medicine dispenser is used, the driving screw 32 is rotated, the driving screw 32 drives the thorn piece 33 to move towards the direction close to the needle core 4 until the thorn piece 33 is positioned inside the needle tube 2, the needle core 4 is pulled out towards the outer side of the needle tube 2, the annular air bag piece I5, the annular air bag piece II 12 and the annular air bag piece III 19 which are expanded on the surface of the piston 3 can be contacted with the thorn piece 33, and the annular air bag piece I5, the annular air bag piece II 12 and the annular air bag piece III 19 can be broken.

The above are only typical examples of the present invention, and besides, the present invention may have other embodiments, and all the technical solutions formed by equivalent substitutions or equivalent changes are within the scope of the present invention as claimed.

Claims

1. The utility model provides a medical medicine dispenser, includes liquid outlet (1), needle tubing (2), piston (3), nook closing member (4), liquid outlet (1) is located needle tubing (2) one end, piston (3) are installed in nook closing member (4) tip and are located needle tubing (2), characterized by:

an annular air bag sheet I (5) is arranged on the circumferential outer side wall of the piston (3), an air inflation cavity I (6) is formed between the annular air bag sheet I (5) and the outer side wall of the piston (3), and an air passage I (7) communicated with the air inflation cavity I (6) is arranged in the piston (3);

a second annular air bag sheet (12) is arranged on the circumferential outer side wall of the piston (3), a second inflation cavity (13) is formed between the second annular air bag sheet (12) and the outer side wall of the piston (3), and a second air passage (14) communicated with the second inflation cavity (13) is arranged in the piston (3);

a first inflation channel (9) is arranged in the stylet (4), one end of the first inflation channel (9) is communicated with the first air passage (7), and a first inflation rod (8) is arranged in the other end of the first inflation channel (9) in a sealing and sliding manner;

a second inflation channel (16) is arranged in the stylet (4), one end of the second inflation channel (16) is communicated with a second air passage (14), and a second inflation rod (15) is arranged in the other end of the second inflation channel (16) in a sealing and sliding manner;

be equipped with drive spout (26) on nook closing member (4), pole (8) tip, the pole (15) tip of aerifing all are located drive spout (26), be equipped with drive slider (27) in drive spout (26), drive slider (27) tip is equipped with wedge face (28), wedge face (28) can offset in proper order with pole (8) rod end, the pole (15) rod end of aerifing, and then drive pole (8) and aerify that first inflation channel (9) slide, drive pole (15) are aerifyd the second and are aerifyd passageway (16) and slide.

2. A medical dispenser as claimed in claim 1, wherein: the end part of the needle core (4) is provided with a first inserted rod (10), the first inserted rod (10) is inserted into the piston (3), a first air vent (11) is formed in the first inserted rod (10), and the first air vent (11) is communicated with the first inflation channel (9) and the first air passage (7).

3. A medical dispenser as claimed in claim 2, wherein: the end part of the needle core (4) is provided with a second inserted rod (17), the second inserted rod (17) is inserted into the piston (3), a second air vent (18) is arranged on the second inserted rod (17), and the second air vent (18) is communicated with a second air inflation channel (16) and a second air passage (14).

4. A medical dispenser as claimed in any one of claims 1 to 3, wherein: an annular air bag sheet III (19) is further arranged on the circumferential outer side wall of the piston (3), an air inflation cavity III (20) is formed between the annular air bag sheet III (19) and the outer side wall of the piston (3), and an air passage III (21) communicated with the air inflation cavity III (20) is arranged in the piston (3);

a third inflation channel (22) is arranged in the stylet (4), one end of the third inflation channel (22) is communicated with the third air passage (21), and an inflation rod III (23) is arranged in the other end of the third inflation channel (22) in a sealing and sliding manner;

the wedge-shaped surface (28) can be sequentially abutted against the rod end of the first inflation rod (8), the rod end of the second inflation rod (15) and the rod end of the third inflation rod (23), so that the first inflation rod (8) is driven to slide along the first inflation channel (9), the second inflation rod (15) is driven to slide along the second inflation channel (16), and the third inflation rod (23) is driven to slide along the third inflation channel (22).

5. The medical dispenser as set forth in claim 4 wherein: the end part of the needle core (4) is provided with a third inserted rod (24), the third inserted rod (24) is inserted into the piston (3), a third air vent (25) is arranged on the third inserted rod (24), and the third air vent (25) is communicated with a third inflation channel (22) and a third air passage (21).

6. A medical dispenser as claimed in claim 5, wherein: and sealing rings (29) are arranged among the first inflation rod (8), the second inflation rod (15) and the third inflation rod (23) and the corresponding first inflation channel (9), the second inflation channel (16) and the third inflation channel (22).

7. A medical dispenser as claimed in claim 1, wherein: the tip that needle tubing (2) deviates from liquid outlet (1) is equipped with outside turn-ups (30), run through on turn-ups (30) and be equipped with screw hole (31), screw hole (31) internal thread connection has drive screw (32), the tip that drive screw (32) are close to nook closing member (4) is equipped with thorn piece (33), drive screw (32) can drive thorn piece (33) and remove to in needle tubing (2).

8. A medical dispenser according to claim 7, wherein: the cutting edge of the thorn piece (33) is circular, and the plane of the cutting edge of the thorn piece (33) is parallel to the sliding direction of the needle core (4).

9. A medical dispenser as claimed in claim 1, wherein: be equipped with stopper (34) on the lateral wall of nook closing member (4), be equipped with a plurality of spacing recesses (35) on drive slider (27) lateral wall, a plurality of spacing recesses (35) are arranged along the direction of sliding of drive slider (27), stopper (34) tip can the one-to-one insert in spacing recess (35).