Dosage injector

Abstract

A quantitative dispensing syringe is provided. The quantitative dispensing syringe comprises two pressure blocks (1), an outer sleeve (2), and a spindle (3). By providing the two pressure blocks (1) on the outer sleeve (2) to limit the snap fit to the spindle (3), the volume of liquid flowing into the outer sleeve (2) can be controlled during liquid aspiration, and the volume of the first level of liquid to be dispensed can be controlled during liquid dispensing, thereby achieving the objective of controlling the dispensing volume and avoiding the problem of medical accidents caused by excessive single dispensing volumes. The position of the spindle (3) relative to the pressure blocks (1) can then be adjusted so that the spindle (3) is pushed further into the outer sleeve (2) so that the total amount of liquid dispensed can be effectively determined by dispensing the remaining liquid to define the volume of the second level of dispensed liquid.

Description

Technical Field

[0001] This application relates to the field of medical devices, particularly to metering syringes.

Background Art

[0002] A syringe is a device used to eject (inject) or extract a liquid. Usually, a syringe has markings with graduations indicating the volume of the internal liquid.

[0003] Existing syringes rely on manual observation of the graduations to determine the ejection volume, which is highly susceptible to human error. Excessive ejection (injection) may occur, leading to an overdose of a single dose and potential medical accidents.

[0004] Therefore, the current syringe structure lacks an effective mechanism for restricting the ejection volume, making it difficult to accurately control the dosage. This may result in an excessive single-dose ejection and pose a risk of medical incidents.

Summary of the Invention

[0005] Embodiments of this application provide a metering syringe having a limiting structure for controlling the ejection volume, addressing the technical problem of the existing syringe structure lacking precise volume limitation that can lead to excessive ejection (injection) and medical accidents.

[0006] Embodiments of this application provide a quantitative syringe comprising two pressing blocks, an outer sleeve and a core, the core being slidably disposed inside the outer sleeve, the core being provided with a push handle, a rod body and a push head, the push handle being located outside the outer sleeve, the push head being located inside the outer sleeve, the rod body being located inside the outer sleeve and connected to the push handle and push head at both ends, respectively, the rod body having a first limiting structure at the end adjacent to the push head and a second limiting structure at the end adjacent to the push handle, between the first and second limiting structures Provided with a gap therein, the two pressing blocks are positioned at the end of the outer sleeve adjacent to the push handle and snap-fit ​​to the outer sleeve, and the two pressing blocks are provided with an inner blocking surface for engaging with a first limiting structure and an outer blocking surface for engaging with a second limiting structure, so that when the spindle is pulled out from the outer sleeve to draw in the liquid, the inner blocking surface blocks the first limiting structure to limit the volume of liquid drawn into the outer sleeve, and when the spindle is pushed into the outer sleeve to discharge the liquid, the outer blocking surface blocks the second limiting structure to limit the first stage discharge volume of the liquid.

[0007] Furthermore, the first limiting structure is a limiting step, the second limiting structure is a limiting rib, the two pressing blocks are arranged opposite each other to form a cross-shaped guide groove, the rod body is a cross-shaped guide rod, and the cross-shaped guide rod coincides with the cross-shaped guide groove.

[0008] Furthermore, the cross-shaped guide groove includes a first guide groove and a second guide groove, the depth direction of the first guide groove is perpendicular to the depth direction of the second guide groove, the depth of the first guide groove is equal to the thickness of the cross-shaped guide rod, and the depth of the second guide groove is equal to the sum of the thicknesses of the cross-shaped guide rod and the limiting rib.

[0009] Furthermore, when the spindle is pushed into the outer sleeve to dispense the liquid, the limiting rib corresponds to the first guide groove, and the edge of the first guide groove acts as an outer blocking surface.

[0010] Furthermore, four protrusions are provided between the first guide groove and the second guide groove, and the spindle is rotatable so as to crush and deform the protrusions in order to switch the limiting rib from a state corresponding to the first guide groove to a state corresponding to the second guide groove, and when the limiting rib corresponds to the second guide groove, the limiting rib is slidable along the second guide groove, and the spindle is pushed into the outer sleeve to discharge the remaining liquid and limit the second stage discharge volume of the liquid.

[0011] Furthermore, the protrusion is provided with a squeeze hole, so that when the core rotates and crushes the protrusion, the squeeze hole also deforms accordingly.

[0012] Furthermore, the two pressing blocks are hinged symmetrically to the ends of the outer sleeve adjacent to the push handle via connecting ribs, the outer sleeve is provided with two clamping platforms, each clamping platform is provided with a positioning hole, and each pressing block is provided with a positioning post facing the positioning hole of the clamping platform, the positioning post engaging with the positioning hole.

[0013] Furthermore, two symmetrically positioned snap through-holes are provided on both side edges of each clamping platform, and each pressing block is provided with a hook facing the snap through-hole of the clamping platform, the hook passing through the snap through-hole and engaging therewith.

[0014] Furthermore, the metering syringe also includes a piston, which is located outside the push head and is interlocked with the inner wall of the outer sleeve.

[0015] Furthermore, the quantitative syringe further comprises a needle tube and a needle protector, the needle tube being connected to the end of the outer sleeve and corresponding to the push head, the needle protector being sleeve-connected to the end of the outer sleeve and the needle tube being positioned inside the needle protector.

[0016] Furthermore, the rod body is further provided with auxiliary limiting ribs, which are positioned between the limiting step and the limiting rib, and two auxiliary limiting ribs are provided, and two limiting ribs are provided, and the cross-shaped guide rod is provided with four convex ribs of the same thickness, two auxiliary limiting ribs are symmetrically positioned on two convex ribs of the cross-shaped guide rod, and two limiting ribs are symmetrically positioned on the other two convex ribs of the cross-shaped guide rod, and the auxiliary limiting ribs and limiting ribs are arranged alternately along the circumferential direction of the cross-shaped guide rod, and a rotational gap is provided between the distribution area of ​​the auxiliary limiting ribs along the longitudinal direction of the cross-shaped guide rod and the distribution area of ​​the limiting ribs along the longitudinal direction of the cross-shaped guide rod.

[0017] Furthermore, multiple distribution regions of the auxiliary restricting ribs are provided along the length of the cross-shaped guide rod, and each distribution region of the auxiliary restricting ribs is provided with two symmetrically arranged auxiliary restricting ribs, and a rotational gap is provided between adjacent distribution regions of the auxiliary restricting ribs, and the auxiliary restricting ribs in adjacent distribution regions are arranged on two sets of convex ribs of the cross-shaped guide rod.

[0018] Furthermore, the two pressing blocks are hinged symmetrically to the ends of the outer sleeve adjacent to the push handle, or the two pressing blocks are positioned separately from the outer sleeve.

[0019] Embodiments of this application provide a precise and easy-to-operate quantitative syringe. By positioning two pressure blocks in the outer sleeve to restrict the movement of the core and engage with it, the objective of limiting the suction volume when drawing in the liquid and limiting the first-stage discharge volume when dispensing the liquid is achieved, thereby enabling precise control of the dosage and avoiding medical accidents caused by dispensing (injecting) an excessive single dose. Furthermore, by adjusting the relative position between the core and the pressure blocks, the core can be pushed further into the outer sleeve to effectively control the total discharge volume by limiting the second-stage discharge volume by dispensing the remaining liquid. [Brief explanation of the drawing]

[0020] [Figure 1]This is a schematic diagram of the structure of a metering syringe provided by an embodiment of the present application. [Figure 2] This is a schematic diagram of the structure of the metering syringe in FIG. 1 after sucking the liquid agent. [Figure 3] This is an exploded view of a part of the structure of the metering syringe in FIG. 2. [Figure 4] This is a schematic diagram of the structure of the metering syringe in an embodiment of the present application in a state of discharging the volume of the liquid agent in the first stage. [Figure 5] This is a schematic diagram of the rotation principle of the mandrel corresponding to FIG. 4. [Figure 6] This is a schematic diagram of the structure of the metering syringe in an embodiment of the present application in a state of discharging the volume of the liquid agent in the second stage. [Figure 7] This is a schematic diagram of the rotation principle of the mandrel corresponding to FIG. 6. [Figure 8] This is a schematic diagram of the structure of the mandrel, the pressing block and the outer sleeve of the metering syringe in an embodiment of the present application when snap-fitting is not performed. [Figure 9] This is a schematic diagram of the structure of the mandrel, the pressing block and the outer sleeve of the metering syringe in an embodiment of the present application when snap-fitting is performed. [Figure 10] This is a schematic diagram of the structure of the mandrel, the pressing block and the outer sleeve of the metering syringe in an embodiment of the present application after snap-fitting. [Figure 11] This is a schematic diagram of the structure of the positioning post of the pressing block engaged with the positioning hole of the outer sleeve of the metering syringe in an embodiment of the present application after snap-fitting. [Figure 12] This is a schematic diagram of the structure of the hook of the pressing block engaged with the snap-through hole of the metering syringe in an embodiment of the present application after snap-fitting. [Figure 13] This is a schematic diagram of the structure of another metering syringe provided by an embodiment of the present application. [Figure 14] This is a schematic diagram of the structure of the segment switching of the metering syringe provided by an embodiment of the present application. [Figure 15] This is a schematic diagram of the structure of still another metering syringe provided by an embodiment of the present application.

Best Mode for Carrying Out the Invention

[0021] To more clearly explain the technical solutions in the embodiments of the present application, the accompanying drawings required for describing the embodiments are briefly introduced below. It should be understood that the following drawings show only some embodiments of the present application and should not be construed as limiting the scope.

[0022] The technical solutions in the embodiments of the present application are clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Of course, the described embodiments are only a part rather than all of the embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts also fall within the protection scope of the present application.

[0023] It should be noted that in the description of the present application, the terms "installed", "connected" and "connection" should be construed in a broad sense unless specifically stated and limited. For example, it may be a fixed connection, a removable connection or an integral connection, it may be a mechanical connection, an electrical connection or a communication connection, it may be a direct connection or an indirect connection through an intermediate medium, internal communication between two elements or an interaction relationship between two elements. Those skilled in the art can understand the specific meanings of the above terms in the present application according to specific situations.

[0024] Embodiment 1 Refer to FIGS. 1 to FIG. 8. Embodiment 1 of the present application provides a metering syringe. The metering syringe is precise and easy to operate, and has features such as extremely easy operation, anti-misoperation design and precise metering discharge.

[0025] Refer to FIGS. 1, 2 and 3. The metering syringe provided by the embodiment of the present application includes two pressing blocks 1, an outer sleeve 2 and a mandrel 3.

[0026] Of these, the spindle 3 is slidably positioned inside the outer sleeve 2. The spindle 3 is provided with a push handle 31, a rod body 32, and a push head 33. The push handle 31 is located outside the outer sleeve 2, the push head 33 is located inside the outer sleeve 2, and the rod body 32 is also located inside the outer sleeve 2 and is connected to the push handle 31 and the push head 33 at both ends, respectively. A first limiting structure is provided at the end of the rod body 32 adjacent to the push head 33, and the first limiting structure is preferably a limiting step 34. A second limiting structure is provided at the end of the rod body 32 adjacent to the push handle 31, and the second limiting structure is preferably a limiting rib 35. A gap is provided between the first limiting structure and the second limiting structure, that is, the gap is provided between the limiting step 34 and the limiting rib 35. The two pressing blocks 1 are symmetrically hinged to the ends of the outer sleeve 2 adjacent to the push handle 31 and snap-fit ​​into the outer sleeve 2. The two pressing blocks 1 are provided with an inner blocking surface 110 for engaging with a limiting step 34 (first limiting structure) and an outer blocking surface 120 for engaging with a limiting rib 35 (second limiting structure). See Figure 2. When the spindle 3 is pulled out from the outer sleeve 2 to draw in the liquid, the inner blocking surface 110 blocks the limiting step 34 (first limiting structure) and limits the volume of liquid drawn into the outer sleeve 2. When the limiting step 34 (first limiting structure) contacts the inner blocking surface 110, it indicates that the liquid drawing has reached the set volume.

[0027] Refer to Figure 4. When the spindle 3 is pushed into the outer sleeve 2 to discharge the liquid, the outer blocking surface 120 blocks the limiting rib 35 (second limiting structure) and limits the first stage discharge volume of the liquid.

[0028] Refer to Figure 3. The two pressing blocks 1 are positioned opposite each other to form a cross-shaped guide groove 10. The rod body 32 is a cross-shaped guide rod, which coincides with the cross-shaped guide groove 10, allowing the core rod 3 to slide smoothly inside the outer sleeve 2 without getting stuck or tilting.

[0029] Refer to Figure 3. The cross-shaped guide groove 10 includes a first guide groove 101 and a second guide groove 102. The depth direction of the first guide groove 101 is perpendicular to the depth direction of the second guide groove 102. The depth of the first guide groove 101 matches the thickness of the cross-shaped guide rod, and the depth of the second guide groove 102 matches the combined thickness of the cross-shaped guide rod and the limiting rib 35.

[0030] Refer to Figure 3. When the spindle 3 is pushed into the outer sleeve 2 to discharge the liquid, the limiting rib 35 corresponds to the first guide groove 101, and the edge of the first guide groove 101 acts as the outer blocking surface 120.

[0031] Refer to Figure 3. Four protrusions 103 are provided between the first guide groove 101 and the second guide groove 102. The spindle 3 may be rotated in such a way that it crushes and deforms the protrusions 103, thereby switching the limiting rib 35 from a state corresponding to the first guide groove 101 to a state corresponding to the second guide groove 102. When the limiting rib 35 corresponds to the second guide groove 102, the limiting rib 35 may slide along the second guide groove 102, and the spindle 3 is pushed into the outer sleeve 2 in such a way that it limits the second stage discharge volume of the liquid by discharging the remaining liquid.

[0032] Refer to Figure 3. A squeeze hole 104 is provided in the projection 103. Refer to Figures 5 and 7. When the core rod 3 rotates and crushes and deforms the projection 103, the squeeze hole 104 also deforms accordingly.

[0033] It is understood that the cross-shaped guide rod has four concave guide grooves and four convex guide rails. The two pressing blocks 1 are provided with four projections 103 in the cross-shaped guide grooves 10, and each projection 103 is provided with a squeeze hole 104. The projections 103 are aligned with the concave guide grooves, and the first guide groove 101 and the second guide groove 102 are aligned with the convex guide rails. To start the first stage of liquid discharge, the spindle 3 is first rotated. During rotation, the four convex guide rails of the spindle 3 crush the four projections 103 of the pressing block 1, deforming the projections 103, and thereby deforming the squeeze holes 104 as well. After rotating past the projections 103, the four convex guide rails of the spindle 3 enter the concave grooves of the pressing block 1, and the four projections 103 of the pressing block 1 again provide restrictive guidance. At this time, the spindle 3 is pushed in to compress and discharge the liquid. The limiting rib 35 of the spindle 3 comes into contact with the outer blocking surface 120 of the pressing block 1, completing the first stage of liquid discharge according to the set volume. Rotating the spindle 3 provides tactile feedback for crushing and positioning, and the limiting rib 35 determines the discharge volume for the first stage.

[0034] Refer to Figures 3, 8, 9, 10, 11, and 12. The two pressing blocks 1 are hinged symmetrically to the ends of the outer sleeve 2 adjacent to the push handle 31 via connecting ribs 11. The connecting ribs 11 are flexible and may be inverted, and connect the two pressing blocks 1 and the outer sleeve 2 as a whole. The outer sleeve 2 is provided with two clamping platforms 21, each clamping platform 21 having a positioning hole 211. Each pressing block 1 is provided with a positioning post 12 facing the positioning hole 211 of the clamping platform 21, and the positioning post 12 engages with the positioning hole 211.

[0035] Refer to Figures 8 and 12. Two symmetrically arranged snap through-holes 212 are provided on both side edges of each clamping platform 21. Each pressing block 1 is provided with a hook 13 facing the snap through-hole 212 of the clamping platform 21, and the hook 13 passes through the snap through-hole 212 and engages therewith.

[0036] Specifically, the outer sleeve 2 and the two pressing blocks 1 are injection molded as a single part. During assembly, the pressing blocks 1 are inverted to deform the connecting ribs 11. The hooks 13 of the pressing blocks 1 pass through the snap holes 212 of the outer sleeve 2 and engage with the clamping platform 21 to prevent detachment. At the same time, the positioning posts of the pressing blocks 1 enter the positioning holes of the outer sleeve 2. In this way, the pressing blocks 1 are precisely positioned and do not easily detach.

[0037] Refer to Figure 1. The quantitative syringe further includes a piston 4. The piston 4 is located outside the push head 33 and interlocks with the inner wall of the outer sleeve 2.

[0038] It is understood that the piston 4 is provided with an end face and the outer sleeve 2 is provided with a core bottom face. The second guide groove 102 is a larger concave groove relative to the first guide groove 101. When starting the second stage of liquid discharge, the spindle 3 is first rotated. During rotation, the four convex guide rails of the spindle 3 crush the four projections 103 of the pressing block 1, deforming the projections 103, and thereby deforming the squeeze hole 104 as well. After rotating past the projections 103, the four convex guide rails of the spindle 3 enter the second guide groove 102 of the pressing block 1, and the four projections 103 of the pressing block 1 again provide restrictive guidance. At this time, the restrictive rib 35 avoids the outer blocking surface 120 and enters the larger concave groove of the pressing block 1. For the second time, the spindle 3 is pushed in to compress and discharge the liquid. The end face of the piston 4 contacts the core bottom surface of the outer sleeve 2, completing the second stage of liquid discharge.

[0039] Refer to Figure 1. The quantitative syringe further includes a needle tube 5 and a needle protector 6. The needle tube 5 is connected to the end of the outer sleeve 2 and corresponds to the push head 33. The needle protector 6 is sleeve-connected to the end of the outer sleeve 2, and the needle tube 5 is positioned inside the needle protector 6.

[0040] Refer to Figures 2, 4, 5, 6, and 7. When using a quantitative syringe, the pressure block 1 is fixed to the outer sleeve 2 at its flange end. The pressure block 1 is provided with a cross-shaped guide groove 10 that forms a limiting through-hole at its center. When the spindle 3 is pulled outward to draw liquid, the cross-shaped guide rod of the spindle 3 can easily pass over the pressure block 1 of the outer sleeve 2 via the guide slope. At the same time, by rotating and adjusting the position of the spindle 3, the contour of the cross-shaped guide rod of the spindle 3 can precisely pass through the limiting through-hole at the center of the pressure block 1. At this time, the rotation angle of the spindle 3 requires high precision. When the spindle 3 is pressed inward to discharge liquid, the position of the spindle 3 is rotated and adjusted. The cross-shaped guide rod of the spindle 3 cannot easily pass over the elastic hook 13 of the outer sleeve 2, and at this time, adjusting the rotation angle of the spindle 3 is relatively easy. This allows the operator to recognize that the syringe has dispensed a specific amount of liquid and that this dose is a specially set dose. An identifier such as an arrow, dot, or scale line is provided at this stopping position. To continue dispensing, the position of the spindle 3 is rotated and adjusted again for the next dispensing step. In this way, excessive dispensing (injection) can be prevented, the dispensing volume of the syringe can be controlled, precise extraction or transfer of the drug can be achieved, the detection accuracy of the associated instruments can be improved, and medical accidents can be prevented.

[0041] Embodiment 2 Embodiment 2 of this application includes most of the technical features of Embodiment 1, with the difference being that Embodiment 2 does not include the squeeze hole 104 of Embodiment 1, i.e., the projection 103 is not provided with the squeeze hole 104. The projection 103 is preferably made of a flexible and elastic material. When the core rod 3 rotates and crushes and deforms the projection 103, rotation of the rod body 32 in the cross-shaped guide groove 10 is still achievable even without the squeeze hole 104.

[0042] The specific details of this embodiment refer to the contents of Embodiment 1 and will not be repeated here.

[0043] Embodiment 3 Embodiment 3 of this application includes most of the technical features of Embodiment 1, with the difference being that this embodiment can achieve multi-stage limiting.

[0044] As shown in Figure 13, auxiliary limiting ribs 36 are further provided on the rod body 32. The auxiliary limiting ribs 36 are positioned between the limiting step 34 and the limiting rib 35. Two auxiliary limiting ribs 36 and two limiting ribs 35 are provided. The cross-shaped guide rod is provided with four convex ribs of the same thickness. Two auxiliary limiting ribs 36 are symmetrically positioned on two convex ribs of the cross-shaped guide rod, and two limiting ribs 35 are symmetrically positioned on the other two convex ribs of the cross-shaped guide rod. The auxiliary limiting ribs 36 and limiting ribs 35 are arranged alternately along the circumferential direction of the cross-shaped guide rod, and the rotational gap 37 is provided between the distribution area of ​​the auxiliary limiting ribs 36 along the longitudinal direction of the cross-shaped guide rod and the distribution area of ​​the limiting ribs 35 along the longitudinal direction of the cross-shaped guide rod.

[0045] As shown in Figure 14, the depths of the first guide groove 101 and the second guide groove 102 are different. For example, the depth of the first guide groove 101 is greater than the depth of the second guide groove 102. When the limiting rib 35 corresponds to the first guide groove 101, the spindle 3 can slide along the length of the outer sleeve 2 to achieve suction or discharge of the liquid.

[0046] When the auxiliary limiting rib 36 contacts the outer sleeve 2, the auxiliary limiting rib 36 acts as a limiting function. At this time, the spindle 3 is rotatable so that the auxiliary limiting rib 36 aligns with the first guide groove 101. At this time, the spindle 3 is further slidable along the length of the outer sleeve 2, and the limiting rib 35 contacts the outer sleeve 2 and acts as a limiting function.

[0047] The two symmetrically positioned end faces are coplanar, forming a positioning circular platform.

[0048] It is understandable that the end faces of the limiting rib 35 and the auxiliary limiting rib 36 along their longitudinal direction protrude from the outer surface of the spindle 3. The end faces of the limiting rib 35 and the auxiliary limiting rib 36 along their longitudinal direction achieve a limiting function and achieve a limiting effect for single-stage dose. The rotation gap 37 provides a range of rotation for the rod body 32 of the spindle 3 in the cross-shaped guide groove 10.

[0049] Furthermore, multiple distribution regions of the auxiliary restricting ribs 36 are provided along the longitudinal direction of the cross-shaped guide rod. Each distribution region of the auxiliary restricting ribs 36 is provided with two symmetrically arranged auxiliary restricting ribs 36. The rotating gap 37 is provided between adjacent distribution regions of the auxiliary restricting ribs 36. The auxiliary restricting ribs 36 in adjacent distribution regions are arranged on two sets of convex ribs of the cross-shaped guide rod.

[0050] Here, two convex ribs, arranged linearly and symmetrically, form one set. The other pair of convex ribs, arranged in a cross shape on a cross-shaped guide rod, form the other set.

[0051] This embodiment gives the user the option to use one, two, or multiple stages. For example, if only one stage is used, only one stage's worth is drawn in for direct discharge.

[0052] If two stages are required, first only the first stage's worth is drawn in, then the spindle 3 is rotated to draw in the second stage's worth, the first stage's worth is discharged, and then the spindle 3 is rotated to discharge the second stage's worth. Alternatively, the user may be given multiple stage options by setting up multiple structures for switching between the first and second stages.

[0053] Furthermore, the outer sleeve 2 is provided with an integrated pressing block 1 that can be reversed and locked for assembly. The top and bottom surfaces also act as positioning for the first stage, second stage, or multiple stages. The pressing block 1 is provided with a cross-shaped through hole and projections that allow the spindle 3 to slide in one direction and provide tactile feedback during stage switching. The spindle 3 is provided with positioning ribs for first stage suction and first stage discharge, and the spindle 3 also has a positioning circular platform for second stage suction. The spindle 3 is cross-shaped, allowing it to slide in one direction within the outer sleeve and providing clear tactile feedback when switching between the first and second stages, making operation easier.

[0054] Embodiment 4 As shown in Figure 15, Embodiment 4 of this application includes most of the technical features of Embodiments 1 to 3, with the difference being that the two pressing blocks 1 are arranged separately from the outer sleeve 2.

[0055] The outer sleeve 2 and the separation positioning pressing block 1 can be directly locked and assembled. The top and bottom surfaces also act as positioning elements for the first stage, second stage, or multiple stages. The pressing block 1 is provided with a cross-shaped through hole and projections, allowing the spindle 3 to slide in one direction, providing tactile feedback between stage transitions and facilitating operation.

[0056] Embodiments of this application provide a precise and easy-to-operate quantitative syringe. By positioning two pressure blocks in the outer sleeve to restrict the movement of the core and engage with it, the objective of limiting the suction volume when drawing in the liquid and limiting the first-stage discharge volume when dispensing the liquid is achieved, thereby enabling precise control of the dosage and avoiding medical accidents caused by dispensing (injecting) an excessive single dose. Furthermore, by adjusting the relative position between the core and the pressure blocks, the core can be pushed further into the outer sleeve to effectively control the total discharge volume by limiting the second-stage discharge volume by dispensing the remaining liquid.

[0057] The embodiments of this application also have the following additional advantages: 1. High precision for small-bore dispensing, 2. A stable and controllable limiting structure to ensure accurate administration. 3. Low cost and relatively simple structure, 4. Design with minimal residue, 5. The central rod moves along a set trajectory, providing guidance to prevent misoperation and tactile feedback. 6. When adjusting the discharge volume, the shaft should provide tactile feedback with excellent recognition.

[0058] In the embodiments described above, each description of the various embodiments has its own emphasis. For aspects not described in detail in a particular embodiment, references may be made to the relevant descriptions in other embodiments.

[0059] The above provides a detailed description of the quantitative syringe provided by embodiments of this application. Specific examples are used herein to illustrate the principles and practices of this application. The above description of embodiments is provided solely to help understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they may further modify the technical solutions described in the above embodiments or substitute some of the technical features accordingly. These modifications or substitutions will not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments of this application. [Explanation of symbols]

[0060] 1. Pressing block 10 Cross-shaped guide grooves 101 First guide groove 102 Second guide groove 103 Protrusion 104 Squeeze holes 11 connecting ribs 12 Positioning Posts 13 hooks 110 Inner shielding surface 120 Outer blocking surface 2 Outer sleeve 21 Platform for clamps 211 Positioning holes 212 snap through holes 3 Mandrel 31 Push handle 32 Rod body 33 Push Head 34. Restricted step height 35 Restriction Ribs 36 Auxiliary Restriction Ribs 37 Rotation gap 4 pistons 5 needle tube 6 Needle protector

Claims

1. A quantitative syringe comprising two pressure blocks, an outer sleeve, and a core, The spindle is slidably arranged inside the outer sleeve, and the spindle is provided with a push handle, a rod body and a push head, the push handle is located outside the outer sleeve, the push head is located inside the outer sleeve and the rod body is located inside the outer sleeve and connected to the push handle and the push head at both ends, the first limiting structure is provided at the end of the rod body adjacent to the push head, the second limiting structure is provided at the end of the rod body adjacent to the push handle and a gap is provided between the first limiting structure and the second limiting structure. The two pressing blocks are positioned at the end of the outer sleeve adjacent to the push handle and snap-fitted to the outer sleeve, and the two pressing blocks are provided with an inner blocking surface for engaging with the first limiting structure and an outer blocking surface for engaging with the second limiting structure. When the shaft is withdrawn from the outer sleeve to draw in the liquid, the inner blocking surface blocks the first limiting structure to limit the volume of the liquid drawn into the outer sleeve, and when the shaft is pushed into the outer sleeve to discharge the liquid, the outer blocking surface blocks the second limiting structure to limit the first stage discharge volume of the liquid. Metering syringe.

2. The quantitative syringe according to claim 1, wherein the first limiting structure is a limiting step, the second limiting structure is a limiting rib, the two pressing blocks are arranged opposite each other to form a cross-shaped guide groove, the rod body is a cross-shaped guide rod, and the cross-shaped guide rod coincides with the cross-shaped guide groove.

3. The quantitative syringe according to claim 2, wherein the cross-shaped guide groove comprises a first guide groove and a second guide groove, the depth direction of the first guide groove is perpendicular to the depth direction of the second guide groove, the depth of the first guide groove is equal to the thickness of the cross-shaped guide rod, and the depth of the second guide groove is equal to the sum of the thicknesses of the cross-shaped guide rod and the limiting rib.

4. The quantitative syringe according to claim 3, wherein when the core is pushed into the outer sleeve to discharge the liquid, the limiting rib corresponds to the first guide groove, and the edge of the first guide groove acts as the outer blocking surface.

5. The quantitative syringe according to claim 4, wherein four protrusions are provided between the first guide groove and the second guide groove, the spindle is rotatable such as to crush and deform the protrusions in order to switch the limiting rib from a state corresponding to the first guide groove to a state corresponding to the second guide groove, when the limiting rib corresponds to the second guide groove, the limiting rib is slidable along the second guide groove, and the spindle is pushed into the outer sleeve so as to discharge the remaining liquid and limit the second stage discharge volume of the liquid.

6. The quantitative syringe according to claim 5, wherein the projection is provided with a squeeze hole, and when the core rotates and crushes and deforms the projection, the squeeze hole also deforms accordingly.

7. The quantitative syringe according to claim 1, wherein the two pressing blocks are hinged symmetrically to the end of the outer sleeve adjacent to the push handle via connecting ribs, the outer sleeve is provided with two clamping platforms, each clamping platform is provided with a positioning hole, and each pressing block is provided with a positioning post facing the positioning hole of the clamping platform, the positioning post engaging with the positioning hole.

8. The quantitative syringe according to claim 7, wherein two symmetrically arranged snap through-holes are provided on both side edges of each clamping platform, and each pressing block is provided with a hook facing the snap through-hole of the clamping platform, the hook passing through the snap through-hole and engaging therewith.

9. The quantitative syringe according to claim 1, further comprising a piston, the piston being located outside the push head and interfering with the inner wall of the outer sleeve.

10. The quantitative syringe according to claim 1, further comprising a needle tube and a needle protector, wherein the needle tube is connected to the end of the outer sleeve and corresponds to the push head, the needle protector is sleeve-connected to the end of the outer sleeve, and the needle tube is disposed inside the needle protector.

11. The quantitative syringe according to claim 5, wherein the rod body is further provided with auxiliary limiting ribs, the auxiliary limiting ribs are arranged between the limiting step and the limiting rib, two auxiliary limiting ribs are provided, two limiting ribs are provided, the cross-shaped guide rod is provided with four convex ribs of the same thickness, the two auxiliary limiting ribs are symmetrically arranged on two convex ribs of the cross-shaped guide rod, the two limiting ribs are symmetrically arranged on the other two convex ribs of the cross-shaped guide rod, the auxiliary limiting ribs and the limiting ribs are arranged alternately along the circumferential direction of the cross-shaped guide rod, and a rotational gap is provided between the distribution area of ​​the auxiliary limiting ribs along the longitudinal direction of the cross-shaped guide rod and the distribution area of ​​the limiting ribs along the longitudinal direction of the cross-shaped guide rod.

12. The quantitative syringe according to claim 11, wherein the plurality of distribution regions of the auxiliary restricting ribs are provided along the longitudinal direction of the cross-shaped guide rod, each distribution region of the auxiliary restricting ribs is provided with two symmetrically arranged auxiliary restricting ribs, a rotational gap is provided between adjacent distribution regions of the auxiliary restricting ribs, and the auxiliary restricting ribs in adjacent distribution regions are arranged on two sets of convex ribs of the cross-shaped guide rod.

13. The quantitative syringe according to claim 1, wherein the two pressing blocks are hinged symmetrically to the end of the outer sleeve adjacent to the push handle, or the two pressing blocks are arranged separately from the outer sleeve.

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