Labor-saving injector for high-viscosity medicine

Abstract

The utility model belongs to the field of instruments for inputting a medium into a human body or onto the human body, and particularly discloses a labor-saving injector for high-viscosity medicine, which comprises a main shell, a piston, a mandrel screw, a sleeve screw and a sectioning nut assembly, a liquid storage cavity is arranged in the main shell, the piston is limited to only perform translational motion along the axial direction relative to the main shell, and the mandrel screw and the sleeve screw are arranged in the liquid storage cavity. The sleeve screw wraps the mandrel screw, and the sleeve screw and the mandrel screw are matched through equidirectional threads with small lead difference to form a differential transmission mechanism; the sleeve screw rod is formed by splicing two semicircular cylinder screw rods tensioned by an elastic connecting piece, and is spirally connected with an openable split nut assembly at the near end of the main shell. According to the differential screw principle, rotary input is converted into trace axial propulsion, and the mechanical gain is high; meanwhile, the design of the split nut and the split type sleeve is combined, rapid decoupling and resetting of a thread pair are achieved, and the clinical surgery operation efficiency and the injection precision are remarkably improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of the instrument that medium is input into human body or is transported to human body, concretely relates to a labor saving injector of high viscosity medicine. BACKGROUND

[0002] In clinical operation in orthopedics, neurosurgery and stomatology department, doctors often need to use high viscosity medical material to fill, fix or repair, and the existing high viscosity medicine injection usually directly uses general medical injector, however, there are following obvious defects in actual clinical operation.

[0003] First, medical bone cement and other materials belong to typical high viscosity non-newtonian fluid, and the viscosity increases rapidly with the solidification time, when using ordinary straight push type injector, the fluid flows through small needle and generates greater back pressure, and medical staff must exert great thumb pushing force to extrude medicine.

[0004] Second, due to the exertion of greater muscle strength, physiological tremor of hand is inevitable, and in delicate microsurgery, the coating range is usually in millimeter level, and slight shaking of hand easily leads to medicine overflow and pollution of surrounding tissue, even fragile nerves or blood vessels are damaged due to instantaneous injection pressure being too large, and the operation risk is increased.

[0005] Third, although the introduction of screw transmission mechanism can reduce the demand of pushing force, but the conventional screw mechanism leads to slow moving speed of push rod, and in the operation process, when the medicine needs to be replaced or resucked, the operator needs to rotate reversely for hundreds of times to reset the piston, and the low reset efficiency seriously drags the operation process and increases the anesthesia waiting time of patient. UTILITARY MODEL CONTENT

[0006] The utility model provides a labor saving injector of high viscosity medicine to solve the technical problems that the operation is laborious, the hand tremor affects the operation precision and the reset efficiency of conventional screw transmission mechanism is low when the high viscosity bone cement is injected in prior art.

[0007] In order to solve the above technical problems, the utility model provides the following technical scheme:

[0008] A labor saving injector of high viscosity medicine, comprising:

[0009] A main shell is formed with a liquid storage cavity in the inside;

[0010] A piston is slidably fitted in the liquid storage cavity, and the piston is limited to only axial translation relative to the main shell;

[0011] A core shaft screw is rigidly connected to the proximal end of the piston;

[0012] A sleeve screw coaxially covers the outside of the mandrel screw, the sleeve screw is composed of two half-cylinder screws; the outer surface of the sleeve screw is provided with a first external thread, the first external thread has a first lead value; the inner surface of the sleeve screw is provided with a first internal thread, the first internal thread has a second lead value; the first external thread and the first internal thread have the same direction, and the first lead value and the second lead value are not equal, so that the axial displacement generated by the rotation of the sleeve screw and the axial displacement of the mandrel screw relative to the sleeve screw form a differential fit; the outer surface of the mandrel screw is provided with a second external thread matched with the first internal thread;

[0013] A split nut assembly is installed at the proximal end of the main shell, the split nut assembly includes two threaded slides, the inner side of the threaded slide is provided with a second internal thread matched with the first external thread.

[0014] Further, the two half-cylinder screws are connected by an elastic connecting piece, the elastic connecting piece is configured to have a pre-tightening force to push the two half-cylinder screws outward in the radial direction.

[0015] Further, the outer walls of the two half-cylinder screws are respectively provided with an insertion slot extending in the axial direction, and the two ends of the elastic connecting piece are provided with matching insertion pieces; the insertion pieces are slid into the interior of the insertion slots in a direction parallel to the axial direction of the sleeve screw, so as to realize the sliding connection of the elastic connecting piece and the half-cylinder screw.

[0016] Further, the splicing surface of one of the half-cylinder screws is provided with a guide column, and the corresponding position of the other half-cylinder screw is provided with a guide hole, and the guide column is inserted into the interior of the guide hole.

[0017] Further, the top end of each half-cylinder screw is integrally formed with a half-cylinder knob; when the two half-cylinder screws are spliced, the two half-cylinder knobs are closed to form a complete injection knob.

[0018] Further, it further includes an adjusting screw, the adjusting screw crosses the main shell, the main structure of the adjusting screw includes two threaded rod segments with opposite directions, each threaded rod segment is respectively threadedly connected with one threaded slide, for driving the two threaded slides to open and close synchronously.

[0019] Further, one end of the adjusting screw extends to the outside of the main shell and is inserted with an opening and closing knob.

[0020] Furthermore, the main housing is provided with a guide bar with a T-shaped cross-section, and the threaded slider is provided with a guide groove with a T-shaped cross-section. The threaded slider forms a sliding connection with the main housing through the cooperation of the guide groove and the guide bar.

[0021] Furthermore, the sleeve screw and the mandrel screw are made of different materials.

[0022] Furthermore, the cross-sections of the main housing and the piston are non-circular.

[0023] The advantages of this utility model compared to the prior art are:

[0024] This invention utilizes the minute lead difference between the sleeve screw and the mandrel screw to form a fully differential screw drive system. When the user rotates the injection knob, the actual displacement of the piston is only the difference between the first and second lead values. This design achieves a huge reduction ratio and thrust amplification factor, allowing the operator to overcome the huge back pressure of high-viscosity bone cement with only a small fingertip torque, reducing hand tremors caused by excessive force, achieving micron-level injection precision, effectively protecting the patient's fragile lesion tissue, and improving surgical safety. Attached Figure Description

[0025] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0026] Figure 1 This is a front view of the pre-injection working conditions according to an embodiment of the present invention;

[0027] Figure 2 for Figure 1 A cross-sectional view along the AA direction;

[0028] Figure 3 for Figure 1 A cross-sectional view along the BB direction;

[0029] Figure 4 This is a front view of the post-injection working condition according to an embodiment of the present invention;

[0030] Figure 5 for Figure 4 A cross-sectional view along the CC direction;

[0031] Figure 6 for Figure 4 A cross-sectional view along the DD direction;

[0032] Figure 7 This is a perspective view of the reset condition according to an embodiment of the present utility model;

[0033] The labels in the diagram represent the following:

[0034] 1-Main housing; 11-Liquid storage chamber; 12-Adjusting screw; 121-Threaded rod section; 122-Opening / closing knob; 13-Guide bar; 2-Piston; 3-Mandrel screw; 4-Sleeve screw; 41-Semi-cylindrical screw; 411-Slot; 412-Guide post; 413-Guide hole; 42-Elastic connector; 421-Insertion piece; 43-Push-in knob; 431-Semi-cylindrical knob; 5-Split nut assembly; 51-Threaded slider; 52-Guide groove. Detailed Implementation

[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0036] In the clinical medical field, especially in surgical scenarios such as minimally invasive orthopedic surgery, neurosurgical repair, or dental filling, in order to overcome the high back pressure generated by medical bone cement or other high-viscosity biomaterials with non-Newtonian fluid properties during micro-injection, and at the same time reduce the impact of operator hand tremors on surgical accuracy, this embodiment provides a labor-saving syringe for high-viscosity drugs.

[0037] refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5The core support structure of the labor-saving syringe is the main shell 1, which contains an elliptical liquid reservoir 11. To directly push the fluid and prevent the moving parts from spinning idly, an elliptical piston 2 is slidably fitted inside the liquid reservoir 11. Because both the inner wall of the main shell 1 and the piston 2 have non-circular geometric cross-sections, the piston 2 is strictly limited to axial translational movement and cannot rotate circumferentially. Furthermore, a mandrel screw 3 is rigidly connected to the proximal end of the piston 2, giving the mandrel screw 3 the same axial movement freedom, without rotation. To construct the product... The device generates a differential kinematic chain with high mechanical gain. It includes a sleeve screw 4 coaxially covering the outside of the mandrel screw 3. The sleeve screw 4 is composed of two semi-cylindrical screws 41 joined together, and has a double thread interface: its outer surface has a first external thread with a large first lead value (e.g., 1.0 mm); its inner surface has a first internal thread with a smaller second lead value (e.g., 0.8 mm). In order to drive the entire system and control the opening and closing of the nut, a split nut assembly 5 is installed near the main housing 1, which includes two threaded sliders 51. The inner side of the slider has a second internal thread that mates with the first external thread.

[0038] refer to Figure 3 and Figure 7 In order to give the sleeve screw 4 a radial opening tendency to facilitate reset, the two semi-cylindrical screws 41 are connected by an elastic connector 42.

[0039] The specific connection method is as follows: slots 411 extending axially are respectively provided on the outer walls of the two semi-cylindrical screws 41, and matching inserts 421 are provided at both ends of the elastic connector 42; by sliding the inserts 421 into the interior of the two slots 411 in a direction parallel to the axial direction of the sleeve screw 4, the sliding connection between the elastic connector 42 and the screw body is realized; the elastic connector 42 is configured to have a pre-tension force, always attempting to push the two semi-cylindrical screws 41 radially outward.

[0040] refer to Figure 3 To ensure the thread accuracy after splicing, a guide post 412 is provided on the splicing surface of one of the semi-cylindrical screws 41, and a guide hole 413 is provided at the corresponding position of the other semi-cylindrical screw 41. When the guide post 412 is inserted into the guide hole 413 to achieve plug-in engagement, the relative position of the two semi-cylindrical bodies is precisely locked, thereby ensuring that the thread trajectory on the surface of the sleeve screw 4 is continuous and without misalignment.

[0041] refer to Figure 3 and Figure 7To facilitate user operation and rotation, each semi-cylindrical screw 41 has a semi-cylindrical knob 431 integrally formed at its top. When two semi-cylindrical screws 41 are spliced ​​together, the two semi-cylindrical knobs 431 are also closed, forming a complete injection knob 43. The user can drive the sleeve screw 4 by rotating the injection knob 43.

[0042] refer to Figure 6 and Figure 7 The opening and closing action of the two threaded sliders 51 is uniformly controlled by the adjusting screw 12; the adjusting screw 12 passes through the main housing 1, and its main structure includes two threaded rod segments 121 with opposite directions of rotation (for example, one segment is a left-hand thread and the other segment is a right-hand thread), and each threaded rod segment 121 is threadedly connected to a threaded slider 51.

[0043] Furthermore, one end of the adjusting screw 12 extends to the outside of the housing and is connected to an opening and closing knob 122, which the user can drive by rotating the opening and closing knob 122.

[0044] refer to Figure 2 , Figure 6 and Figure 7 To ensure the stability of the slider's movement, the main housing 1 is provided with a guide bar 13 with a T-shaped cross-section. Correspondingly, the threaded slider 51 is provided with a guide groove 52 with a T-shaped cross-section. The threaded slider 51 forms a sliding connection with the main housing 1 through the cooperation of the guide bar 13 and the guide groove 52, thereby restricting the slider's other degrees of freedom except for radial movement.

[0045] To prevent thread seizing under high loads and extend service life, the sleeve screw 4 and the mandrel screw 3 are made of dissimilar materials; preferably, the mandrel screw 3 is made of stainless steel, while the sleeve screw 4 is made of high-performance engineering plastics (such as PEEK) or brass.

[0046] The working principle of this utility model is as follows:

[0047] refer to Figure 2 and Figure 5 During injection, the user rotates the opening / closing knob 122, which drives the two threaded sliders 51 to move inward along the guide bar 13 and close and lock them in place via the adjusting screw 12. At this time, the operator rotates the injection knob 43, and the sleeve screw 4 is driven forward spirally relative to the main housing 1 by the split nut assembly 5. On the other hand, due to the rotation and forward movement of the sleeve screw 4, the internal non-rotating mandrel screw 3 is forced to retract backward relative to the sleeve screw 4. Through the above differential motion, the piston 2 achieves a high-precision micro-injection.

[0048] refer to Figure 7When a reset is required, the user rotates the opening and closing knob 122 in the opposite direction, and the adjusting screw 12 drives the two threaded sliders 51 to separate radially outward along the guide bar 13. Once the outer constraint is released, the inner sleeve screw 4 automatically expands radially under the action of the elastic connector 42, causing the threads to disengage. At this time, the operator can pinch the injection knob 43 by hand to pull the sleeve screw 4 axially back to reset, and directly pull the mandrel screw 3 to complete the reinstallation. Finally, the opening and closing knob 122 is rotated again to lock the mechanism and restore the injection state.

[0049] The above embodiments are merely exemplary embodiments of this utility model and are not intended to limit this utility model. The scope of protection of this utility model is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this utility model within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered as falling within the scope of protection of this utility model.

Claims

1. A labor-saving syringe for high-viscosity drugs, characterized in that, include: The main shell (1) has a liquid storage cavity (11) inside it. The piston (2) is slidably fitted in the liquid storage chamber (11), and the piston (2) is restricted to axial translational movement relative to the main housing (1); The mandrel screw (3) is rigidly connected to the proximal end of the piston (2); A sleeve screw (4) is coaxially wrapped around the outside of the mandrel screw (3). The sleeve screw (4) is formed by splicing two semi-cylindrical screws (41). The outer surface of the sleeve screw (4) is provided with a first external thread, which has a first lead value. The inner surface of the sleeve screw (4) is provided with a first internal thread, which has a second lead value. The first external thread and the first internal thread have the same direction of rotation, and the first lead value and the second lead value are not equal, so that the axial displacement generated when the sleeve screw (4) rotates and the axial displacement of the mandrel screw (3) relative to the sleeve screw (4) form a differential fit. The outer surface of the mandrel screw (3) is provided with a second external thread that fits with the first internal thread. The split nut assembly (5) is installed at the near end of the main housing (1). The split nut assembly (5) includes two threaded sliders (51), and the inner side of the threaded sliders (51) is provided with a second internal thread that mates with the first external thread.

2. The labor-saving syringe according to claim 1, characterized in that, The two semi-cylindrical screws (41) are connected by an elastic connector (42) configured to have a pre-tension force that pushes the two semi-cylindrical screws (41) radially outward.

3. The labor-saving syringe according to claim 2, characterized in that, The outer walls of the two semi-cylindrical screws (41) are respectively provided with slots (411) extending along the axial direction, and the two ends of the elastic connector (42) are provided with matching inserts (421); the inserts (421) slide into the interior of the slots (411) in a direction parallel to the axial direction of the sleeve screw (4) to realize the sliding connection between the elastic connector (42) and the semi-cylindrical screw (41).

4. The labor-saving syringe according to claim 1, characterized in that, One of the semi-cylindrical screws (41) has a guide post (412) on its splicing surface, and the other semi-cylindrical screw (41) has a guide hole (413) at the corresponding position, with the guide post (412) inserted into the guide hole (413).

5. The labor-saving syringe according to claim 1, characterized in that, Each of the semi-cylindrical screws (41) has a semi-cylindrical knob (431) integrally formed at its top end; when the two semi-cylindrical screws (41) are spliced ​​together, the two semi-cylindrical knobs (431) close to form a complete injection knob (43).

6. The labor-saving syringe according to claim 1, characterized in that, It also includes an adjusting screw (12), which passes through the main housing (1). The main structure of the adjusting screw (12) includes two threaded rod segments (121) with opposite directions of rotation. Each threaded rod segment (121) is threadedly connected to a threaded slider (51) to drive the two threaded sliders (51) to open and close synchronously.

7. The labor-saving syringe according to claim 6, characterized in that, One end of the adjusting screw (12) extends to the outside of the main housing (1) and is connected to an opening and closing knob (122).

8. The labor-saving syringe according to claim 1, characterized in that, The main housing (1) is provided with a guide bar (13) with a T-shaped cross section, and the threaded slider (51) is provided with a guide groove (52) with a T-shaped cross section. The threaded slider (51) forms a sliding connection with the main housing (1) through the cooperation of the guide groove (52) and the guide bar (13).

9. The labor-saving syringe according to claim 1, characterized in that, The sleeve screw (4) and the mandrel screw (3) are made of different materials.

10. The labor-saving syringe according to claim 1, characterized in that, The cross-sections of the main housing (1) and the piston (2) are non-circular.

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