Medical injector

Abstract

The invention discloses a medical syringe, which belongs to the technical field of syringes and comprises a needle cylinder, a cover plate is fixedly arranged at one end of the needle cylinder, a support plate is arranged on one side, away from the needle cylinder, of the cover plate, a chock plug is slidably arranged in the needle cylinder, a connecting rod is arranged at one end, close to the cover plate, of the chock plug, and the part, close to the top end, of the connecting rod penetrates through the support plate. The outer side of the connecting rod is sleeved with a lantern ring, the lantern ring can drive the connecting rod to rotate synchronously through a positioning unit, and the connecting rod can move in the axis direction relative to the lantern ring in the rotating process of the connecting rod. In the process that a medical worker drives the cantilever to deflect in a reciprocating mode, the gear can drive the lantern ring and the connecting rod to rotate in the single direction, and therefore the chock plug is continuously driven to move in the direction away from the needle tube. Therefore, liquid medicine in the medicine bottle can be quickly extracted.

Description

Technical Field

[0001] The present invention relates to the technical field of syringes, in particular to a medical syringe. Background Art

[0002] A syringe is a structure used for the process of needle extraction and injection of gas or liquid.

[0003] Chinese invention patent CN116036417A discloses a medical syringe. Through the piston connection structure, when the push rod moves in the needle tube, the piston is connected to the piston connection structure. The piston connection structure includes a piston sealing column arranged on the inner wall of the needle tube. One end of the piston sealing column is connected to the inner wall of the needle tube, and the other end of the piston sealing column is a free end. The piston sealing column is provided with a smooth surface. The function of the piston connection structure is to cooperate with the piston to improve the overall sealing of the syringe, prevent external air from entering the syringe, and improve the safety of the syringe.

[0004] The above-mentioned device improves the stability of the movement of the push rod and the push plate by cooperating with the retaining block and the slide groove. However, during the process of extracting the medicine with the syringe, it is difficult for medical staff to operate the syringe with one hand, which causes inconvenience in use. In summary, there is still room for improvement in the above-mentioned device.

[0005] Therefore, it is necessary to provide a medical syringe to solve the above-mentioned technical problems. Summary of the invention

[0006] The purpose of the present invention is to provide a medical syringe to solve the problem that the existing device proposed in the above background technology improves the stability of the movement of the push rod and the push plate by cooperating with the retaining block and the slide groove, but it is difficult for medical staff to operate the syringe with one hand during the process of extracting the medicine.

[0007] Based on the above ideas, the present invention provides the following technical solutions: a medical syringe, comprising a syringe, a cover plate is fixedly provided at one end of the syringe, a support plate is provided on the side of the cover plate away from the syringe, a plug is slidably provided inside the syringe, a connecting rod is provided at the end of the plug close to the cover plate, a portion of the connecting rod close to the top passes through the support plate, a collar is sleeved on the outside of the connecting rod, the collar can drive the connecting rod to rotate synchronously through a positioning unit, and the connecting rod can move relative to the collar along its axial direction during the rotation process; A gear is sleeved on the outer side of the collar, and the gear can rotate in a single direction relative to the collar. A rack meshing with the gear is slidably mounted on the support plate. During the reciprocating movement of the rack relative to the support plate, the meshing of the rack and the gear can drive the connecting rod to rotate in a single direction. The connecting rod and the cover plate are matched with a limiting unit, so that the connecting rod can move along the axial direction of the syringe during the rotation relative to the cover plate.

[0008] As a further solution of the present invention: the positioning unit includes a positioning bar fixedly connected to the inner wall of the collar, and a positioning groove slidingly matched with the positioning bar is opened on the outer peripheral wall of the connecting rod, and the positioning groove is arranged along the axial direction of the connecting rod.

[0009] As a further solution of the present invention: the limiting unit includes a limiting block fixedly connected to the cover plate, a through hole matching with the connecting rod is opened at the center position of the cover plate, the limiting block is fixedly arranged on the inner wall of the through hole, and a limiting groove slidingly matched with the limiting block is opened on the outer peripheral wall of the connecting rod, and the limiting groove is arranged in a spiral shape.

[0010] As a further solution of the present invention: cantilevers are hinged on both sides of the top of the support plate, a sliding bar is arranged under the cantilever, the sliding bar is slidably matched with the support plate, and the sliding bar is fixedly connected to the rack through a pillar, a sliding block is fixedly arranged on the top surface of the sliding block, and a sliding groove is opened on the cantilever for slidingly matching with the sliding block.

[0011] As a further solution of the present invention: a pressure plate is rotatably mounted on the top end surface of the connecting rod, and the pressure plate and the connecting rod are elastically matched, and both sides of the top surface of the pressure plate are integrally formed with protrusions.

[0012] As a further solution of the present invention: a circular hole is opened on the bottom end surface of the pressure plate and near the center, the part of the connecting rod near the top extends into the circular hole, a clamping block is elastically installed on the outer peripheral wall of the connecting rod, the end surface of the clamping block away from the connecting rod is set as an inclined surface, and a clamping groove matching the clamping block is opened on the inner wall of the circular hole.

[0013] As a further solution of the present invention: a mounting hole is opened at the top wall inside the circular hole, a pull rod is fixedly arranged on the top end face of the connecting rod, the part of the pull rod away from the connecting rod and the cross-section of the mounting hole are both arranged to be T-shaped, one end of the pull rod away from the connecting rod is rotatably arranged in the mounting hole, and a limiting spring is arranged between the connecting rod and the top surface inside the circular hole.

[0014] As a further solution of the present invention: two bosses are integrally formed on one side of the support plate close to the cantilever, a plug rod is fixedly provided on the top surface of the boss, and an annular plug-in portion is integrally formed on the cantilever, so that the plug rod can be inserted into the plug-in portion and rotated to cooperate with the plug-in portion.

[0015] As a further solution of the present invention: an arc spring is installed between the two cantilevers.

[0016] As a further solution of the present invention: the width of the limiting groove is greater than the width of the positioning groove, and the limiting groove is connected to the positioning groove.

[0017] Compared with the prior art, the beneficial effect of the present invention is that when the two cantilevers are driven to deflect outward, the rack will move in the direction close to the connecting rod, thereby driving the gear to rotate in the opposite direction. Since the gear can only drive the ring to rotate in a single direction, the gear is in a state of rotating alone during the outward deflection of the cantilever. The above operation is repeated. When the medical staff drives the cantilever to deflect back and forth, the gear can drive the ring and the connecting rod to rotate in a single direction, thereby continuously driving the plug to move in the direction away from the needle tube. Compared with traditional syringes, the device is convenient for one-handed operation to extract liquid medicine, thereby quickly extracting liquid medicine from the medicine bottle. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a three-dimensional structural schematic diagram of the present invention; Figure 3 It is a schematic diagram of the cooperation between the gear and the rack of the present invention; Figure 4 It is a schematic diagram of the cooperation between the positioning strip and the positioning groove of the present invention; Figure 5 It is a schematic diagram of the limit groove and the positioning groove structure of the present invention; Figure 6 It is a schematic diagram of the cooperation between the rack and the support plate of the present invention; Figure 7 It is a schematic diagram of the cooperation between the connecting rod and the pressing plate of the present invention; Figure 8 It is a schematic diagram of the limit block structure of the present invention; Fig. 9 The present invention Figure 5 A schematic diagram of the enlarged structure at point A; Fig.10 is a schematic diagram of the bump structure of the present invention; Fig.11 It is a schematic diagram of the cooperation between the connecting rod and the plug of the present invention.

[0020] In the figure: 1. syringe; 2. cantilever; 201. plug-in part; 202. slide groove; 3. pressure plate; 301. raised part; 302. slot; 4. slide bar; 401. slider; 5. support plate; 501. boss; 5011. plug rod; 502. strip groove; 503. guide groove; 504. mounting groove; 505. stepped hole; 6. connecting rod; 601. positioning groove; 602. limiting groove; 603. plug; 604. pull rod; 7. rack; 701. clamping strip; 8. collar; 801. convex block; 8011. extrusion surface; 9. gear; 901. notch; 10. clamping block; 1001. inclined surface; 11. cover plate; 1101. limiting block; 12. positioning strip; 13. limiting spring. DETAILED DESCRIPTION

[0021] like Figure 1-Figure 11 As shown, a medical syringe comprises a syringe 1, the bottom end of the syringe 1 is connected to a needle tube, and the top end of the syringe 1 is fixedly provided with a cover plate 11, referring to Figure 1-Figure 3 As shown, a support plate 5 is fixedly provided on the end face of the cover plate 11 away from the syringe 1, a plug 603 is slidably provided inside the syringe 1, and a sealing ring can be fixedly sleeved on the outer side of the plug 603, so that the plug 603 and the syringe 1 are sealed and matched, and a connecting rod 6 is provided on the end face of the plug 603 away from the needle tube, and the connecting rod 6 can be rotatably matched with the plug 603. In actual use, when the connecting rod 6 drives the plug 603 to move in the syringe 1 in the direction away from the needle tube, the external medicine can be drawn into the syringe 1.

[0022] The portion of the connecting rod 6 near the top passes through the support plate 5 and can move freely relative to the support plate 5. A ring 8 is sleeved on the outside of the connecting rod 6, and the ring 8 can drive the connecting rod 6 to rotate synchronously through a positioning unit, and the connecting rod 6 can move relative to the ring 8 along its axial direction during rotation. A gear 9 is sleeved on the outside of the ring 8, and the gear 9 can rotate in a single direction relative to the ring 8. Racks 7 are provided on both sides of the gear 9 on the support plate 5, and the rack 7 is slidably matched with the support plate 5. As a result, during the reciprocating movement of the rack 7 relative to the support plate 5, the connecting rod 6 can be driven to rotate in a single direction through the meshing of the rack 7 and the gear 9, and the connecting rod 6 is matched with the cover plate 11 through a limiting unit, so that the connecting rod 6 can move outward relative to the syringe 1 during the rotation relative to the cover plate 11, thereby facilitating the plug 603 to move relative to the syringe 1 in a direction away from the needle tube.

[0023] The positioning unit includes a positioning bar 12 fixedly connected to the inner wall of the ring 8, and a positioning groove 601 that slidably cooperates with the positioning bar 12 is opened on the outer peripheral wall of the connecting rod 6. The positioning groove 601 is arranged along the axial direction of the connecting rod 6. Through this structure, when the ring 8 rotates, the connecting rod 6 can be driven to rotate through the cooperation between the positioning bar 12 and the positioning groove 601. At the same time, the connecting rod 6 can move along its axial direction relative to the ring 8.

[0024] The limiting unit includes a limiting block 1101 fixedly connected to the cover plate 11, a through hole matched with the connecting rod 6 is opened at the center position of the cover plate 11, and the limiting block 1101 is fixedly set on the inner wall of the through hole, and a limiting groove 602 slidingly matched with the limiting block 1101 is opened on the outer peripheral wall of the connecting rod 6, and the limiting groove 602 is set in a spiral shape. Through this structure, when the ring 8 drives the connecting rod 6 to rotate synchronously, the squeezing force of the limiting groove 602 on the limiting block 1101 can drive the connecting rod 6 to move relative to the syringe 1.

[0025] The width of the limiting groove 602 is greater than the width of the positioning groove 601 , so that the limiting block 1101 will not interfere with the positioning groove 601 when sliding along the limiting groove 602 , and the limiting groove 602 is connected to the positioning groove 601 .

[0026] In order to drive the rack 7 to move, the present invention has cantilevers 2 hinged on both sides of the top of the support plate 5, and a slide bar 4 is arranged below the cantilever 2. Figure 1-Figure 3 As shown, the slide bar 4 can slide along the length direction relative to the support plate 5, and the slide bar 4 and the rack 7 are fixedly connected by a support, so that the slide bar 4 can synchronously drive the rack 7 to move during the movement. A slider 401 is fixedly provided on the top surface of the slide bar 4, and a slide groove 202 that slidably cooperates with the slider 401 is provided on the cantilever 2 along its length direction. Through this structure, when the cantilever 2 deflects, the pressure of the slide groove 202 side against the slider 401 can drive the slide bar 4 and the rack 7 to move relative to the support plate 5, and the cooperation between the rack 7 and the gear 9 can drive the connecting rod 6 to rotate; Reference Figure 3 As shown, the rack 7 is arranged on both sides of the gear 9. In actual use, in order to simplify the structure, the rack 7 can be arranged on only one side of the gear 9. Specifically, the cantilever 2 matched with the rack 7 can be rotatably matched with the support plate 5, and the other cantilever 2 can be fixedly connected to the support plate 5.

[0027] The end of the cantilever 2 away from the syringe 1 is integrally formed with an annular gripping portion. During actual operation, the medical staff can insert their fingers into the gripping portion to drive the cantilever 2 to deflect. Specifically, the medical staff can operate the cantilever 2 with one hand and pick up the medicine bottle with the other hand to insert the needle tube into the medicine bottle. After that, the cantilever 2 is driven to deflect inward, and the slide bar 4 can be driven to move in the direction away from the connecting rod 6 through the cooperation between the slide groove 202 and the slider 401. During this process, the rack 7 will mesh with the gear 9 and drive the gear 9 and the ring 8 to rotate forward, so that the connecting rod 6 can be driven to rotate through the cooperation between the positioning bar 12 and the positioning groove 601, and the connecting rod 6 can be driven to rotate through the cooperation between the spiral limiting groove 602 and the limiting block 1101. Relative to the outward movement of the syringe 1, the plug 603 is used to suck the liquid medicine in the medicine bottle into the syringe 1. When the two cantilevers 2 are driven to deflect outward, the rack 7 will move in the direction close to the connecting rod 6, thereby driving the gear 9 to rotate in the opposite direction. Since the gear 9 can only drive the ring 8 to rotate in a single direction, the gear 9 is in a state of rotating alone during the outward deflection of the cantilever 2. Repeat the above operation. When the medical staff drives the cantilever 2 to deflect back and forth, the gear 9 can drive the ring 8 and the connecting rod 6 to rotate in a single direction, thereby continuously driving the plug 603 to move in the direction away from the needle tube. Compared with traditional syringes, the device is easy to operate with one hand, so that the liquid medicine in the medicine bottle can be quickly extracted.

[0028] like Figure 1-Figure 10 As shown, a pressing plate 3 is rotatably installed at the top end surface of the connecting rod 6, and protrusions 301 are integrally formed on both sides of the top surface of the pressing plate 3. During the process of injecting liquid medicine into the patient's body, the medical staff can place the index finger and the middle finger on both sides of the bottom of the support plate 5, and place the thumb on the top surface of the pressing plate 3 and between the two protrusions 301. During the process of pressing the pressing plate 3 downward, the connecting rod 6 can move toward the inside of the syringe 1, thereby squeezing the liquid medicine in the syringe 1 through the plug 603. Specifically, during the process of the connecting rod 6 moving toward the inside of the syringe 1, the connecting rod 6 can be rotated through the cooperation of the limit block 1101 and the limit groove 602, but due to the rotational cooperation between the pressing plate 3 and the connecting rod 6, during the injection of liquid medicine, the cooperation between the two protrusions 301 and the thumb of the medical staff can keep the pressing plate 3 stable, thereby improving the stability of the injected liquid medicine.

[0029] Furthermore, a circular hole is provided at the bottom end surface of the pressing plate 3 and near the center, and the portion of the connecting rod 6 near the top extends into the circular hole, and a clamping block 10 is elastically installed at the outer peripheral wall of the connecting rod 6, referring to Figure 7As shown, the end face of the card block 10 away from the connecting rod 6 is set as an inclined surface 1001, and the inner wall of the circular hole is provided with a card slot 302 matched with the card block 10. When the card block 10 is in a pop-up state and inserted into the card slot 302, the connecting rod 6 and the pressure plate 3 can be locked; A mounting hole is provided at the top wall inside the circular hole, and a pull rod 604 is fixedly provided on the top end surface of the connecting rod 6. The part of the pull rod 604 away from the connecting rod 6 and the cross section of the mounting hole are both set to be T-shaped, and one end of the pull rod 604 away from the connecting rod 6 is rotatably provided in the mounting hole. Through this structure, the pressure plate 3 and the connecting rod 6 can be rotatably matched, and the pressure plate 3 and the connecting rod 6 will not be separated. A limit spring 13 is provided between the connecting rod 6 and the top surface inside the circular hole, and the limit spring 13 is sleeved on the outside of the pull rod 604; During the injection process, the medical staff places the thumb between the two protrusions 301 and drives the pressure plate 3 to move downward. During this process, the limit spring 13 between the pressure plate 3 and the connecting rod 6 will be compressed, so that the pressure plate 3 can move relative to the connecting rod 6 along its length direction, but due to the resistance of the limit spring 13, the block 10 and the slot 302 do not overlap in the horizontal plane. When the medical staff pushes the pressure plate 3 to move faster suddenly, the resistance of the medicine liquid in the syringe 1 to the plug 603 is used to make the pressure plate 3 further compress the limit spring 13 and move downward relative to the connecting rod 6, so that the block 10 can be aligned with the slot 302. After the block 10 is inserted into the slot 302, the connecting rod 6 and the pressure plate 3 are locked, so that the connecting rod 6 cannot continue to move relative to the pressure plate 3 Continue to rotate, because the thumb of the medical staff is located between the two protrusions 301, the pressing plate 3 and the connecting rod 6 cannot rotate, and when the connection rod 6 cannot be driven to rotate by the cooperation of the limit block 1101 and the limit groove 602, the connecting rod 6 cannot continue to move downward relative to the syringe 1, which helps to prevent the medicine from being quickly pushed into the patient's body. Subsequently, when the thumb of the medical staff gradually leaves the pressing plate 3, the pressing plate 3 can be moved in the direction away from the connecting rod 6 and reset. Since a slope 1001 is provided at one end of the clamping block 10, the clamping block 10 can move out of the clamping groove 302 when the pressing plate 3 moves away from the connecting rod 6, so that the connecting rod 6 and the plug 603 can be slowly pushed through the pressing plate 3 again. Therefore, this structure can be used to more safely inject medicine into the patient's body.

[0030] like Figure 1 As shown, in order to install the cantilever 2, the present solution has two bosses 501 integrally formed on one side of the support plate 5 close to the cantilever 2, and an insertion rod 5011 is fixedly provided on the top surface of the boss 501, and an annular plug-in portion 201 is integrally formed on the cantilever 2, so that the insertion rod 5011 can be inserted into the plug-in portion 201 and rotatably cooperate with the plug-in portion 201, and the plug-in portion 201 is roughly located in the middle position of the cantilever 2.

[0031] An arc spring is installed between the two cantilevers 2, which can cause the two cantilevers 2 to deflect outwards. Figure 3 As shown, the inner side of the rack 7 near the slide bar 4 is a smooth structure. When the drug liquid is extracted and the cantilever 2 is in a non-gripping state, the arc spring can drive the cantilever 2 to deflect outward and remain stable, so that the gear 9 is located at the smooth structure on the side of the rack 7, thereby avoiding the gear 9 from meshing with the rack 7, so that during the process of pressing the pressure plate 3, the gear 9 and the rack 7 will not interfere with each other.

[0032] Reference Figure 2 As shown, the top surface of the support plate 5 is provided with guide grooves 503 at both ends of the slide bar 4, and guide blocks that slide with the guide grooves 503 are fixedly provided on both sides of the bottom surface of the slide bar 4. Of course, the cross-sections of the guide blocks and the guide grooves 503 can be set to T-shaped.

[0033] The top surface of the support plate 5 is provided with a strip groove 502 , and the support column fixed between the rack 7 and the slide bar 4 slides in the strip groove 502 .

[0034] Reference Figure 4 As shown, the length of the positioning strip 12 is greater than the pitch of the limiting groove 602 , so that the positioning strip 12 will not be separated from the positioning groove 601 .

[0035] Combination Figure 3-Figure 4 , Figure 6 As shown, a stepped hole 505 is provided at the center of the support plate 5, and the connecting rod 6 passes through the stepped hole 505 and can move freely relative to the support plate 5, and the above-mentioned ring 8 and gear 9 are both installed in the stepped hole 505. Specifically, the top end faces of the ring 8 and the gear 9 are in contact with the inner top wall of the stepped hole 505, and the bottom end faces of the ring 8 and the gear 9 are in contact with the top surface of the cover plate 11. Through this structure, the stability of the ring 8 and the gear 9 can be maintained, and a mounting groove 504 connected to the stepped hole 505 is provided on the support plate 5, and the mounting groove 504 is connected to the above-mentioned strip groove 502, the rack 7 slides in the mounting groove 504, and a T-slot is provided on the inner wall of the mounting groove 504, and a clamping strip 701 is fixedly provided on a side of the rack 7 close to the T-slot, and the cross-section of the clamping strip 701 is T-shaped, and the clamping strip 701 slides in the T-slot.

[0036] Reference Figure 7 As shown, a groove for slidingly cooperating with the clamping block 10 is provided on the outer peripheral wall of the connecting rod 6 , and a first spring is fixedly arranged between the inner end surface of the groove and the clamping block 10 .

[0037] Reference Figure 10-11As shown, in actual operation, the collar 8 and the gear 9 can be matched through a one-way bearing, so that the gear 9 can only drive the collar 8 to rotate in a single direction. Another implementation method is given in this scheme, in which a rectangular groove is provided on the outer peripheral wall of the collar 8, and a protrusion 801 is slidably arranged in the rectangular groove, and a second spring is fixedly arranged between the protrusion 801 and the inner end face of the rectangular groove, and the end of the protrusion 801 away from the collar 8 is set as an inclined extrusion surface 8011, and a plurality of notches 901 matched with the protrusion 801 are provided on the inner wall of the gear 9. Through this structure, the one-way matching between the collar 8 and the gear 9 can also be achieved.

[0038] The cross section of the connecting rod 6 near the plug 603 is T-shaped, and a circular hole matching the bottom end of the connecting rod 6 is provided on the top of the plug 603. Similarly, the cross section of the circular hole is T-shaped, so that the bottom end of the connecting rod 6 can be rotatably set in the circular hole.

Claims

1. A medical syringe, comprising a syringe, a cover plate fixedly arranged at one end of the syringe, a support plate arranged at the side of the cover plate away from the syringe, a plug slidably arranged inside the syringe, and a connecting rod arranged at the end of the plug close to the cover plate, characterized in that: The portion of the connecting rod near the top passes through the support plate, and a collar is sleeved on the outside of the connecting rod. The collar can drive the connecting rod to rotate synchronously through the positioning unit, and the connecting rod can move relative to the collar along its axial direction during the rotation process; A gear is sleeved on the outer side of the collar, and the gear can rotate in a single direction relative to the collar. A rack meshing with the gear is slidably mounted on the support plate. During the reciprocating movement of the rack relative to the support plate, the meshing of the rack and the gear can drive the connecting rod to rotate in a single direction. The connecting rod and the cover plate are matched with a limiting unit, so that the connecting rod can move along the axial direction of the syringe during the rotation relative to the cover plate.

2. A medical syringe according to claim 1, characterized in that: The positioning unit comprises a positioning bar fixedly connected to the inner wall of the collar, and a positioning groove slidably matched with the positioning bar is formed on the outer peripheral wall of the connecting rod, and the positioning groove is arranged along the axial direction of the connecting rod.

3. A medical syringe according to claim 2, characterized in that: The limiting unit includes a limiting block fixedly connected to the cover plate, a through hole matched with the connecting rod is opened at the center position of the cover plate, the limiting block is fixedly arranged on the inner wall of the through hole, and a limiting groove slidingly matched with the limiting block is opened on the outer peripheral wall of the connecting rod, and the limiting groove is arranged in a spiral shape.

4. A medical syringe according to claim 3, characterized in that: Cantilevers are hinged on both sides of the top of the support plate, and a sliding bar is arranged under the cantilever. The sliding bar is slidably matched with the support plate, and the sliding bar is fixedly connected to the rack through a support. A sliding block is fixedly arranged on the top surface of the sliding bar, and a sliding groove is opened on the cantilever to slide with the sliding block.

5. A medical syringe according to claim 4, characterized in that: A pressing plate is rotatably mounted on the top end surface of the connecting rod, and the pressing plate and the connecting rod are elastically matched, and both sides of the top surface of the pressing plate are integrally formed with protrusions.

6. A medical syringe according to claim 5, characterized in that: A circular hole is provided at the bottom end surface of the pressure plate near the center, and the portion of the connecting rod near the top extends into the circular hole. A clamping block is elastically installed at the outer peripheral wall of the connecting rod, and the end surface of the clamping block away from the connecting rod is set as an inclined surface, and a clamping groove matching the clamping block is provided on the inner wall of the circular hole.

7. A medical syringe according to claim 6, characterized in that: A mounting hole is opened on the top wall inside the circular hole, and a pull rod is fixedly arranged on the top end face of the connecting rod. The part of the pull rod away from the connecting rod and the cross-section of the mounting hole are both arranged in a T shape. One end of the pull rod away from the connecting rod is rotatably arranged in the mounting hole, and a limiting spring is arranged between the connecting rod and the top surface inside the circular hole.

8. A medical syringe according to claim 4, characterized in that: The support plate has two bosses integrally formed on one side close to the cantilever, a plug rod is fixedly provided on the top surface of the boss, and an annular plug-in portion is integrally formed on the cantilever, so that the plug rod can be inserted into the plug-in portion and rotated with the plug-in portion.

9. A medical syringe according to claim 4, characterized in that: An arc spring is installed between the two cantilevers.

10. A medical syringe according to claim 3, characterized in that: The width of the limiting groove is greater than the width of the positioning groove, and the limiting groove is communicated with the positioning groove.

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