Fixed injection apparatus

Abstract

The present application relates to the technical field of medical instruments. Disclosed is a fixed injection apparatus. The fixed injection apparatus comprises a needle tube, a connecting piece, and a pushing piece. A sheath is arranged around the needle tube, and an open end of the sheath is connected to the connecting piece in a matched mode. The pushing piece is connected to the needle tube, and extends along the axial direction of the sheath from a connection point between the sheath and the connecting piece to the outside of the sheath, so that one part of the pushing piece is arranged inside the sheath, while the other part is arranged outside the sheath. In addition, the pushing piece is movable relative to the needle tube under the action of an external force, and drives the sheath to detach from the connecting piece during the movement. When a medical staff operates the fixed injection apparatus, the medical staff can hold the fixed injection apparatus with one hand and use fingers to apply an external force to the pushing piece arranged outside the sheath, such that the entire sheath can be detached relative to the connecting piece, making the operation simple and convenient.

Description

Fixed injection device Technical Field

[0001] The present application relates to the technical field of medical devices, and in particular to a fixed injection device. Background Art

[0002] Existing fixed injection devices generally include a needle assembly, an injection piece, and a connector that connects and secures the two. The needle assembly generally includes a needle and a sheath, which is typically positioned around the needle to protect it. During operation, medical personnel must first remove the sheath from the needle, insert the needle into a collection vessel, and then draw the liquid from the collection vessel into the injection piece or transfer the liquid from the injection piece to the collection vessel. Alternatively, the needle can be used to puncture a patient's vein, drawing the patient's blood into the injection piece or injecting the liquid from the injection piece into the patient.

[0003] However, medical staff generally need to perform other operations when operating the fixed injection device. For example, when drawing blood or delivering liquids to the patient, they need to press, pat, and other operations on the patient. If the sheath around the needle tube is removed in advance, the needle tube may be contaminated or the needle tube may accidentally injure others. However, if the sheath around the needle tube is not removed in advance, the medical staff will have to press, pat, and other operations on the patient with one hand when drawing blood or delivering liquids to the patient, and it will be difficult to remove the sheath around the needle tube with only the other hand.

[0004] Summary of the Invention

[0005] The technical problem to be solved by the present application is to provide a fixed injection device in order to overcome the defect in the prior art that it is difficult for medical personnel to remove the sheath around the needle tube with one hand during actual operation.

[0006] This application solves the above technical problems through the following technical solutions:

[0007] A fixed injection device, comprising a needle tube and a connector, wherein a sheath is provided on the periphery of the needle tube, and an open end of the sheath is cooperatively connected to the connector, wherein the fixed injection device further comprises:

[0008] a pushing member connected to the needle tube and extending from a connection point between the sheath and the connecting member to an exterior of the sheath along an axial direction of the sheath;

[0009] The pushing member is movable relative to the needle tube under the action of an external force, and drives the sheath to separate from the connecting member during the movement.

[0010] In this solution, a pusher is connected to the needle tube and extends axially from the connection between the sheath and the connector to the outside of the sheath. This allows the pusher to be positioned partially inside the sheath and partially outside the sheath when the open end of the sheath is mated and connected to the connector. The pusher located outside the sheath can then withstand external forces, causing the entire pusher to move relative to the needle tube and, during this movement, disengage the sheath from the connector. When operating this fixed injection device, a medical professional can hold the device in one hand and apply external force to the pusher located outside the sheath with their fingers, thereby detaching the entire sheath from the connector. This operation is simple and convenient.

[0011] Furthermore, the outer wall of the sheath corresponding to the position of the pushing member protrudes outward to form an accommodating cavity, and the pushing member abuts against the bottom of the accommodating cavity during the movement.

[0012] In this solution, through this arrangement, at the position where the push member is set, an accommodating cavity is formed between the outer wall of the sleeve and the connecting member, and the push member can be accommodated in the accommodating cavity. During the movement, the push member abuts against the bottom of the accommodating cavity, making it easier to push the sleeve off the connecting member.

[0013] Furthermore, the pushing member includes a first section and a second section arranged at an angle, the head end of the first section is connected to the needle tube and extends along the axial direction of the sheath from the connection between the sheath and the connecting member to the outside of the sheath, and the end of the first section is connected to the head end of the second section.

[0014] In this solution, by setting the second section of the pusher at an angle to the first section outside the sheath, when external force is applied to the end of the second section, the pusher as a whole undergoes a certain deformation, so that the first section of the pusher can be close to the sheath and abut against the sheath, thereby making it easier for the sheath to detach from the connecting member due to the movement of the pusher.

[0015] Furthermore, along the radial direction of the connecting member, the end of the second section extends outward relative to the head end of the second section.

[0016] In this solution, through this arrangement, the end of the second section is arranged away from the connecting member in the radial direction of the connecting member, avoiding interference between the pushing member and other components. At the same time, when medical staff hold the fixed injection device, it is also more convenient to apply external force to the end of the second section, which is more conducive to the removal of the sheath.

[0017] Furthermore, the pushing member further includes a pressing portion, which is arranged at the end of the second section and has a pressing surface that bears external force.

[0018] In this solution, through this arrangement, a pressing portion is provided at the end of the second section of the pusher, and the pressing surface of the pressing portion is used to bear the external force, making the operation more comfortable and convenient for medical staff.

[0019] Furthermore, the pushing member also includes a fixing ring, which is slidably connected to the periphery of the needle tube, and the first end of the first section is connected to the fixing ring.

[0020] In this solution, through this arrangement, the pusher can be better fixed to the periphery of the needle tube and will not easily fall off during the process of being relative to the needle tube.

[0021] Furthermore, the fixed injection device also includes a needle seat, the needle tube is sealed and inserted into the interior of the needle seat, the needle seat is sealed and inserted into the connecting piece along the axial direction of the connecting piece, and the fixing ring is slidably connected to the periphery of the needle seat.

[0022] In this solution, the needle tube is sealed and inserted into the interior of the needle seat, and the needle seat is connected to the needle tube and then sealed and inserted into the connecting piece together, so as to avoid the radial dimension of the needle tube being too small, resulting in insufficient connection strength between the needle tube and the connecting piece or failure to seal the connection; at the same time, the fixing ring slides relative to the needle tube through the needle seat, which can also avoid the radial dimension of the needle tube being too small, resulting in insufficient strength of the needle tube and bending.

[0023] Furthermore, the fixed injection device also includes a plurality of slides, which are cylindrical with openings at both ends and are nested with each other, the innermost slide is nested on the periphery of the needle seat, and the pusher is connected to the outermost slide; wherein the innermost slide can slide relative to the needle seat and between adjacent slides along the axial direction of the needle tube.

[0024] In this solution, by nesting multiple slides on the periphery of the needle seat, the fixed ring is indirectly connected to the needle seat through multiple slides. Through the mutual sliding between the multiple slides, it is more convenient for the pusher to move relative to the needle seat along the axial direction of the needle tube, thereby driving the sheath to detach from the connecting member.

[0025] Furthermore, one end of the connector for inserting the needle seat extends outwardly in the radial direction of the connector to form an annular wall, and the open end of the sheath is cooperatively connected to the periphery of the annular wall;

[0026] An annular cavity is formed between the annular wall and the connecting member. When the plurality of sliding members are not sliding against each other, one end of the plurality of sliding members close to the connecting member is accommodated inside the annular cavity.

[0027] In the present solution, through this arrangement, when the sheath is removed relative to the needle tube, the presence of the annular wall increases the distance between the sheath and the needle tube, thereby avoiding mutual contact during the removal process; at the same time, when the medical staff needs to remove the sheath, they only need to apply a small force to the pusher to make the outermost slide slide. At this time, the end of the other slides close to the connecting member can still be accommodated inside the annular accommodating cavity, and the end of the outermost slide away from the connecting member will not extend too much beyond the first end of the needle seat, thereby avoiding interference with the position of the slide when the needle tube is inserted into the collection container or punctures the patient's human vein.

[0028] Furthermore, the needle seat and the non-outermost sliding member are provided with a limiting slot at one end away from the connecting member, and each sliding member is provided with a buckle at one end close to the connecting member, and the buckle can be combined with the limiting slot to limit the innermost sliding member from sliding away from the needle seat, and the sliding away of multiple sliding members from each other.

[0029] In this solution, by providing corresponding limit slots and buckles on the needle seat and each slide, it is prevented that the multiple slides are separated during the sliding process.

[0030] Furthermore, the total length of the plurality of slides in the sliding direction is greater than the axial dimension of the needle tube.

[0031] In this solution, through this setting, after the medical staff operates the fixed injection device to complete liquid collection or delivery, they can further push multiple slides so that the multiple slides completely wrap the needle tube, preventing the needle tube from accidentally injuring the medical staff after the operation is completed.

[0032] Furthermore, the fixed injection device also includes an injection piece, which is connected to an end of the connector away from the needle tube, and is used to drive the flow of liquid and contain liquid.

[0033] In this solution, through this arrangement, the injection piece is used to realize the collection and transportation of liquid. At the same time, the injection piece can also drive the flow of liquid, making it easier to promote the outflow of liquid during the liquid collection process.

[0034] Furthermore, the injection component is a syringe, and the nipple of the syringe is sealed and connected to the end of the connector away from the needle tube.

[0035] In this solution, a syringe is directly used as an injection piece, and the nipple of the syringe is sealed and connected to the connector, making the liquid delivery safer. At the same time, the pulling and pulling of the syringe can more conveniently provide driving force for the flow of the liquid, making the liquid collection and delivery process more convenient.

[0036] The positive progress of this application is:

[0037] This fixed injection device is connected to the needle tube by providing a pusher. The pusher extends from the connection between the sheath and the connector to the outside of the sheath in the axial direction of the sheath. When the open end of the sheath is mated with the connector, part of the pusher is located inside the sheath, and the other part is located outside the sheath. In this case, the pusher located outside the sheath can withstand external forces, causing the entire pusher to move relative to the needle tube, and during this movement, the sheath is disengaged from the connector. When operating the fixed injection device, medical personnel can hold the fixed injection device with one hand and use their fingers to apply external force to the pusher located outside the sheath to remove the entire sheath from the connector. This operation is simple and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG1 is a schematic diagram of the overall structure of a fixed injection device in one embodiment of the present application.

[0039] FIG2 is a schematic diagram of the overall structure of a fixed injection device in one embodiment of the present application, wherein the injection part is hidden.

[0040] FIG3 is a schematic diagram of the overall cross-sectional structure of a fixed injection device in one embodiment of the present application.

[0041] FIG4 is a schematic diagram of the overall structure of a fixed injection device in one embodiment of the present application, wherein the injection piece and the sheath are hidden.

[0042] FIG5 is a schematic diagram of the connection and assembly of the needle tube, the needle seat and the connector in one embodiment of the present application.

[0043] FIG6 is a schematic structural diagram of a pushing member in an embodiment of the present application.

[0044] FIG7 is a schematic structural diagram of a connecting member in an embodiment of the present application.

[0045] FIG8 is a schematic structural diagram of an inner layer sliding member in an embodiment of the present application.

[0046] FIG9 is a schematic structural diagram of a middle-layer sliding member in an embodiment of the present application.

[0047] FIG10 is a schematic structural diagram of an outer sliding member in an embodiment of the present application.

[0048] Explanation of the accompanying drawings: Needle tube 10; sheath 11; syringe 20; nipple 21; connecting member 30; annular wall 31; annular cavity 311; needle seat 50; pushing member 60; pressing portion 61; first section 62; second section 63; fixing ring 64; outer layer sliding member 71; middle layer sliding member 72; inner layer sliding member 73; buckle 74; limiting groove 75 DETAILED DESCRIPTION

[0049] The present application is further described below by way of examples, but the present application is not limited to the scope of the examples.

[0050] As shown in Figures 1, 2 and 3, this embodiment provides a fixed injection device, which includes a needle tube assembly, an injection piece and a connector 30 that connects and fixes the two. The needle tube assembly specifically includes a needle tube 10 and a sheath 11. The needle tube 10 is mainly used to puncture the patient's human vein. The sheath 11 is arranged on the periphery of the needle tube 10. The sheath 11 is a structure with one end open and the other end closed, wherein the open end of the sheath 11 is arranged on the periphery of the connector 30 and is connected to the connector 30. The main function of the sheath 11 is to protect the needle tube 10. The injection piece is mainly used to drive the flow of blood and collect blood. In this embodiment, the injection piece specifically adopts a syringe 20, and the nipple 21 of the syringe 20 is threadedly connected to the connector 30.

[0051] During blood collection, medical personnel must first remove the sheath 11 from the connector 30 to separate it from the needle tube 10, then insert the needle tube 10 to puncture the patient's vein. The blood will then pass through the needle tube 10 to the connector 30, and finally be collected into the syringe 20. Similarly, when injecting a liquid into a patient, medical personnel must first remove the sheath 11 from the connector 30 to separate it from the needle tube 10, then insert the needle tube 10 to puncture the patient's vein. The liquid will then pass through the connector 30 to the needle tube 10, and finally be injected into the patient's vein.

[0052] It should be noted that the fixed injection device in this embodiment is primarily used for collecting blood from a patient and injecting liquid into a patient's vein. However, in other embodiments, the fixed injection device can also be used in other situations requiring the collection or injection of liquids. For example, in the medical field, two liquids need to be mixed for the purpose of dispensing a drug. In this case, the fixed injection device can be used to collect a certain amount of one liquid and then inject it into the other liquid. For specific operational details, please refer to the blood collection and liquid injection scenarios in this embodiment.

[0053] In this embodiment, as shown in Figures 2 and 3, the fixed injection device further includes a pusher 60. One end of the pusher 60 is connected to the needle tube 10, and the other end of the pusher 60 extends from the connection between the sheath 11 and the connector 30 to the exterior of the sheath 11 along the axial direction of the sheath 11. When the open end of the sheath 11 is mated with the connector 30, a portion of the pusher 60 is disposed inside the sheath 11, while the other portion is disposed outside the sheath 11. Furthermore, the pusher 60 located outside the sheath 11 can withstand external forces, causing the entire pusher 60 to move relative to the needle tube 10, and during this movement, the sheath 11 can be detached from the connector 30. When performing blood sampling or injecting liquids, medical personnel can hold the fixed injection device in one hand and apply external force to the pusher 60 located outside the sheath 11 with their fingers to remove the entire sheath 11 from the connector 30, making operation simple and convenient.

[0054] In this embodiment, as shown in Figures 2 and 3, the structure of the sheath 11 is compatible with the structure of the connector 30. The overall structure of the sheath 11 is a truncated cone-shaped sleeve structure, and the open end of the sheath 11 is arranged on the periphery of the connector 30 and is connected to the connector 30. However, the outer wall of the sheath 11 corresponding to the position of the pusher 60 protrudes outward to form a receiving cavity. That is, the open end of the sheath 11 and the periphery of the connector 30 cooperate to form a receiving cavity at the position of the pusher 60. The pusher 60 is disposed in the receiving cavity. One end of the pusher 60 is connected to the needle tube 10 in the receiving cavity, and the other end of the pusher 60 extends from the outside of the sheath 11. When the pusher 60 moves under the action of an external force, the pusher 60 can abut the bottom of the receiving cavity to drive the sheath 11 to move, making it easier to push the sheath 11 off the connector 30.

[0055] Furthermore, as shown in Figures 4 and 6 , the pusher 60 specifically includes a first section 62 and a second section 63, which are arranged at an angle. The head end of the first section 62 is connected to the needle tube 10 within the accommodating cavity, and the first section 62 extends along the axial direction of the sheath 11 from the connection between the sheath 11 and the connector 30 to the outside of the sheath 11. On the outside of the sheath 11, the terminal end of the first section 62 is connected to the head end of the second section 63. By arranging the second section 63 of the pusher 60 at an angle to the first section 62 on the outside of the sheath 11, when an external force is applied to the terminal end of the second section 63, the pusher 60 as a whole undergoes a certain deformation, which can cause the first section 62 of the pusher 60 to approach the sheath 11 and abut against it. This makes it easier for the sheath 11 to be separated from the connector 30 by the movement of the pusher 60.

[0056] Specifically, in this embodiment, the distal end of the second segment 63 extends outwardly relative to the head end of the second segment 63 along the radial direction of the connector 30, i.e., the distal end of the second segment 63 extends away from the connector 30. This arrangement allows the distal end of the second segment 63 to be radially spaced away from the connector 30, preventing interference between the pusher 60 and other components. Furthermore, when a medical professional is holding the fixed injection device, it is more convenient to apply external force to the distal end of the second segment 63, further facilitating removal of the sheath 11. Of course, in other embodiments, if the radial dimension of the connector 30 increases, the size of the open end of the sheath 11 will also increase. In this case, the distal end of the second segment 63 may also extend inwardly relative to the head end of the second segment 63 along the radial direction of the connector 30, i.e., the distal end of the second segment 63 extends toward the connector 30, as long as the pusher 60 does not interfere with other components.

[0057] In addition, as shown in Figures 3, 4, and 6, the pusher 60 also includes a pressing portion 61, which is disposed at the end of the second section 63. The pressing portion 61 also has a pressing surface for bearing external forces. The pressing surface is specifically a curved surface, so that when a medical professional holds the fixed injection device, the surface of the thumb can abut against the pressing surface. This arrangement, with the pressing portion 61 disposed at the end of the second section 63 of the pusher 60, allows the pressing surface of the pressing portion 61 to bear external forces, making operation more comfortable and convenient for medical professionals.

[0058] As shown in Figures 3, 4, and 6, the pusher 60 further includes a fixing ring 64, which is slidably disposed around the periphery of the needle tube 10 and can slide back and forth relative to the needle tube 10. The head end of the first section 62 of the pusher 60 is connected to the fixing ring 64. This arrangement allows the pusher 60 to be better secured to the periphery of the needle tube 10 and prevents it from easily dislodging during insertion relative to the needle tube 10. Specifically, as shown in Figure 5, the fixed injection device further includes a needle hub 50, into which the needle tube 10 is sealingly inserted. The needle hub 50 is sealingly inserted into the connector 30 along the axial direction of the connector 30. The fixing ring 64 of the pusher 60 is specifically disposed around the periphery of the needle hub 50. By sealingly inserting the needle tube 10 into the interior of the needle seat 50, the needle seat 50 is connected to the needle tube 10 and then sealedly inserted into the connecting piece 30 together, it is avoided that the radial dimension of the needle tube 10 is too small, resulting in insufficient connection strength between the needle tube 10 and the connecting piece 30 or the inability to seal the connection; at the same time, the fixing ring 64 slides relative to the needle tube 10 through the needle seat 50, which can also avoid the radial dimension of the needle tube 10 being too small, resulting in insufficient strength of the needle tube 10 and bending.

[0059] Furthermore, as shown in Figures 3, 8, 9, and 10, the fixed injection device further includes three sliders, namely an outer slider 71, a middle slider 72, and an inner slider 73. Each slider is a cylindrical structure with open ends and nested with each other. The inner slider 73 is nested around the periphery of the needle seat 50, and the pusher 60 is fixedly connected to the outer slider 71. The inner slider 73 can slide relative to the needle seat 50 and between adjacent sliders along the axial direction of the needle tube 10. By nesting these sliders around the periphery of the needle seat 50, the fixing ring 64 is indirectly connected to the needle seat 50 through these sliders. The sliding movement between these sliders facilitates the movement of the pusher 60 relative to the needle seat 50 along the axial direction of the needle tube 10, thereby driving the sheath 11 to separate from the connecting member 30. It should be noted that, in the present embodiment, the number of slides is set to three, and the three slides are nested with each other, but in other embodiments, the slides can be set to other numbers. The preferred setting is that the number of slides is set corresponding to the length of the needle tube 10. When the length of each slide and the needle tube 10 is certain, by adjusting the number of slides, the medical staff can push the nested slides to make each slide slide with each other after blood collection or liquid injection, thereby completely wrapping the needle tube 10 to prevent the used needle tube 10 from accidentally injuring the medical staff or other personnel.

[0060] Furthermore, as shown in Figures 3, 5 and 7, the connector 30 has an annular wall 31 extending outwardly in the radial direction of the connector 30 at the end where the needle holder 50 is inserted. The open end of the sheath 11 is directly connected to the periphery of the annular wall 31, and an annular cavity 311 is formed between the annular wall 31 and the connector 30. In this embodiment, the annular wall 31 is directly integrally formed with the connector 30. However, in other embodiments, the annular wall 31 and the connector 30 can be separately provided. With this arrangement, when the sheath 11 is removed from the needle tube 10, the presence of the annular wall 31 increases the distance between the sheath 11 and the needle tube 10, thereby avoiding contact with each other during the removal process. In addition, the three slides are nested with each other when they are not sliding against each other, that is, the ends of the three slides close to the connector 30 in the nested state are all accommodated inside the annular cavity 311. With this arrangement, when medical staff need to remove the sheath 11, they only need to apply a small force to the pusher 60 to make the outer slide 71 slide. At this time, the ends of the other slides close to the connector 30 can still be accommodated inside the annular accommodating cavity, and the end of the outer slide 71 away from the connector 30 will not extend too much beyond the first end of the needle seat 50, thereby avoiding interference with the position of the slide when the needle tube 10 punctures the patient's human vein.

[0061] As shown in Figures 5, 8, 9 and 10, a limit slot 75 is provided on the needle seat 50 and the end of the non-outermost slide away from the connector 30, and a buckle 74 is provided on the end of each slide close to the connector 30. The buckle 74 can be combined with the limit slot 75 to limit the inner slide 73 from sliding off the needle seat 50, and to limit the sliding of multiple slides from each other. When the buckles 74 on the three slides are combined with the corresponding limit slots 75, the length of the three slides in the axial direction of the needle tube 10 is the longest. At this time, the total length of the three slides in this direction is greater than the axial dimension of the needle tube 10, so that the multiple slides completely wrap the needle tube 10, preventing the needle tube 10 from accidentally injuring medical personnel after the operation is completed.

[0062] As shown in Figures 1 and 3, the injection piece in this embodiment specifically adopts a syringe 20. The specific structure of the syringe 20 is prior art and will not be described in detail here. The nipple 21 of the syringe 20 is sealedly connected to the end of the connector 30 away from the needle tube 10. During the process of blood collection or liquid injection by medical staff, by pulling the piston of the syringe 20, a driving force can be provided for the flow of blood, and the drawn blood can be accommodated, making the entire blood collection process smoother and reducing the user's pain. Of course, in other embodiments, the injection piece can also have other structures existing in the prior art, as long as it can provide a driving force for the flow of liquid and can accommodate liquid.

[0063] Although the above describes specific embodiments of the present application, those skilled in the art will appreciate that these are merely illustrative and that various changes or modifications may be made to these embodiments without departing from the principles and essence of the present application. Therefore, the scope of protection of this application is defined by the appended claims.

Claims

1. A fixed injection device, comprising a needle tube and a connecting piece, wherein a sheath is disposed on the periphery of the needle tube, and an open end of the sheath is cooperatively connected with the connecting piece, characterized in that: The fixed injection device also includes: A pushing member, the pushing member is connected to the needle tube and extends from a connection point between the sheath and the connecting member to the outside of the sheath along the axial direction of the sheath; The pushing member is movable relative to the needle tube under the action of an external force, and drives the sheath to be separated from the connecting member during the movement.

2. The fixed injection device according to claim 1, characterized in that: The outer wall of the sheath corresponding to the position of the pushing member protrudes outward to form an accommodating cavity, and the pushing member abuts against the bottom of the accommodating cavity during the movement.

3. The fixed injection device according to any one of claims 1 to 2, characterized in that: The pusher includes a first section and a second section arranged at an angle, wherein the head end of the first section is connected to the needle tube and extends from the connection between the sheath and the connector to the outside of the sheath along the axial direction of the sheath, and the end of the first section is connected to the head end of the second section.

4. The fixed injection device according to claim 3, characterized in that: Along the radial direction of the connecting member, the end of the second section extends outward relative to the head end of the second section.

5. The fixed injection device according to any one of claims 3 to 4, characterized in that: The pushing member further includes a pressing portion, which is disposed at the end of the second section and has a pressing surface for bearing external force.

6. The fixed injection device according to any one of claims 3 to 5, characterized in that: The pushing member also includes a fixing ring, which is slidably connected to the periphery of the needle tube, and the head end of the first section is connected to the fixing ring.

7. The fixed injection device according to claim 6, characterized in that: The fixed injection device also includes a needle seat, the needle tube is sealed and inserted into the interior of the needle seat, the needle seat is sealed and inserted into the connecting piece along the axial direction of the connecting piece, and the fixing ring is slidably connected to the periphery of the needle seat.

8. The fixed injection device according to claim 7, characterized in that: The fixed injection device also includes a plurality of slides, which are cylindrical with openings at both ends and are nested with each other, the innermost slide is nested on the periphery of the needle seat, and the pusher is connected to the outermost slide; wherein the innermost slide can slide relative to the needle seat and between adjacent slides along the axial direction of the needle tube.

9. The fixed injection device according to claim 8, characterized in that: One end of the connector for inserting the needle holder extends outwardly in the radial direction of the connector to form an annular wall, and the open end of the sheath is cooperatively connected to the periphery of the annular wall; An annular cavity is formed between the annular wall and the connecting member. When the plurality of sliding members are not sliding against each other, one end of the plurality of sliding members close to the connecting member is accommodated in the annular cavity.

10. The fixed injection device according to any one of claims 8 to 9, characterized in that: The needle seat and the non-outermost sliding member are provided with a limiting slot at one end away from the connecting member, and each sliding member is provided with a buckle at one end close to the connecting member, and the buckle can be combined with the limiting slot to limit the sliding member of the innermost layer from sliding away from the needle seat, and the sliding members from sliding away from each other.

11. The fixed injection device according to claim 10, characterized in that: The total length of the plurality of slide members in the sliding direction is greater than the axial dimension of the needle tube.

12. The fixed injection device according to any one of claims 1 to 11, characterized in that: The fixed injection device also includes an injection piece, which is connected to an end of the connecting piece away from the needle tube, and is used to drive the flow of liquid and contain liquid.

13. The fixed injection device according to claim 12, characterized in that: The injection piece is a syringe, and the nipple of the syringe is sealed and connected to an end of the connector away from the needle tube.

Images