Passive injection pump capable of adjusting thrust

Abstract

The invention relates to the technical field of medical instruments, in particular to a thrust-adjustable passive injection pump which comprises a fixing assembly and a flexible mechanism assembly, the flexible mechanism assembly comprises a base, bearing seats arranged on the two sides of the base, a lead screw arranged in the base, a movable seat, a main spring, an auxiliary spring and a spring pressing plate, the push rod and the hand wheel are arranged on the outer side of the base; the fixing assembly is arranged on the upper surface of the base, and the lead screw penetrates through the bearing seat, the movable seat and the main spring and is sleeved outside the lead screw. The spring pressing plate is in threaded connection with the lead screw and arranged on the side, away from the movable base, of the main spring. The hand wheel is arranged at the end, close to the spring pressing plate, of the lead screw. The auxiliary springs are arranged on the two sides of the movable base, one end of each auxiliary spring is hinged to the movable base, and the other end of each auxiliary spring is hinged to the base. The push rod is arranged on the upper surface of the base, the bottom of the push rod is connected with the movable seat, and the push rod abuts against a piston of the injector. The passive injection pump can be manually adjusted to meet different use requirements.

Description

Technical Field

[0001] The invention relates to the technical field of medical devices, and in particular to a passive injection pump with adjustable thrust. Background Art

[0002] Usually, when medical staff perform intravenous injections for patients, in addition to relying on traditional manual operation methods, they can also use medical syringe pumps to more accurately control the injection process of the liquid medicine. The main function of the syringe pump is to output the power of linear motion, thereby driving the syringe piston to move. The syringe pumps currently on the market can be divided into two types: active and passive.

[0003] Active injection pumps require a power source (such as a battery or mains electricity) to drive the internal actuator (such as a motor, etc.), and use a transmission mechanism to drive the piston movement of the syringe. For example, CN 117357733 A, published in China, introduces a medical injection pump that uses electricity to drive its actuator to work, and can also switch to a manual injection mode in an emergency. In addition, CN 115920175 A, published in China, introduces a medical injection pump that uses a motor to output the power of the injection pump. In order to reduce the impact of the motor's rotational inertia on the injection accuracy during shutdown, an electromagnetic clutch is used to reduce the impact of the motor's inertia, thereby improving the accuracy of the injection pump. Similarly, CN115887835 A, published in China, introduces an active medical injection pump that can be used in an ambient low temperature environment. However, active medical injection pumps are dependent on electricity and cannot be used in environments without power (such as sudden power outages caused by earthquakes, wind and rain, etc., or when working in the field) and in certain special environments (such as MRI strong magnetic field environments).

[0004] Passive injection pumps do not rely on external power to operate. Such devices usually use springs, gravity or other mechanical principles to apply pressure to the syringe piston to promote the flow of liquid medicine. For example, CN 103536987A, a Chinese invention patent, introduces a passive automatic drug injection stand that uses push plates, springs and other components to push the movement of the syringe piston. In addition, CN2098291U, a Chinese utility model patent, introduces a medical intravenous injection drug pushing device that also uses springs and other components to push the movement of the syringe piston. However, the above devices all use a single or multiple springs in parallel to push the syringe piston, and the thrust will inevitably change with the change of the spring length. Therefore, the thrust borne by the syringe piston will also gradually decay during the injection process, resulting in large pressure fluctuations in the syringe, thereby aggravating the patient's discomfort. In addition, the design of the existing passive injection pump also has problems such as difficulty in finely adjusting the thrust borne by the syringe piston, which is not conducive to accurately controlling the drug administration speed and dosage, especially in treatment scenarios that require long-term stable infusion or require extremely high dosage accuracy, which may seriously affect the treatment effect.

[0005] Therefore, it is very important to propose a syringe pump that can solve the above-mentioned technical problems. Summary of the invention

[0006] In order to solve the problem that the thrust of existing passive injection pumps fluctuates greatly and is difficult to finely adjust, the purpose of the present invention is to provide a passive injection pump with adjustable thrust. The passive syringe of the present invention has a flexible mechanism with constant and adjustable thrust to reduce the pressure fluctuation in the syringe, thereby achieving precise adjustment of the thrust of the syringe.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The present invention provides a passive injection pump with adjustable thrust, which is matched with a syringe when in use. The syringe comprises a housing and a piston. A finger holder is arranged at one end of the housing, and an injection head is arranged at the other end. The piston is arranged in the inner cavity of the housing and is allowed to move along the inner cavity of the housing. The passive syringe comprises a fixing component for fixing the housing and a flexible mechanism component for adjusting the thrust.

[0009] The flexible mechanism assembly includes a base, bearing seats arranged on both sides of the base, a screw rod, a moving seat, a main spring, an auxiliary spring and a spring pressure plate arranged in the base, and a push rod and a hand wheel arranged outside the base;

[0010] In which, the fixed assembly is arranged on the upper surface of the base, the lead screw passes through the bearing seat, the movable seat and the main spring are sleeved on the outside of the lead screw, and the movable seat allows axial movement along the lead screw to adjust the compression amount of the main spring; the spring pressure plate is threadedly connected to the lead screw and is arranged on the side of the main spring away from the movable seat, and the handwheel is arranged at the end of the lead screw close to the spring pressure plate, which is used to drive the lead screw to rotate and control the position of the spring pressure plate, control the preload force of the main spring and provide thrust for the movable seat; the auxiliary spring is arranged on both sides of the movable seat, one end is hingedly connected to the movable seat, and the other end is hingedly connected to the base, which is used to provide a flexible thrust for the movable seat; the push rod is arranged on the upper surface of the base, and the bottom is connected to the movable seat. The push rod abuts against the piston and is used to drive the piston to move along the length direction of the lead screw.

[0011] In one embodiment of the present invention, the fixing assembly includes a fixing seat, a pressing plate and a pressing knob;

[0012] The fixing seat is arranged on the upper surface of the base, and a groove for accommodating the shell is arranged on the upper surface of the fixing seat; gaps for fixing the finger holder are symmetrically arranged on both sides of the groove;

[0013] The pressure plate includes an integrated fixing portion and a holding portion; the fixing portion is arranged at the end of the holding portion, and the fixing portion is provided with a first through groove that penetrates the fixing portion and is adapted to the clamping knob. The first through groove allows for active connection with the clamping knob, and cooperates with the fixing seat to fix the shell.

[0014] In one embodiment of the present invention, the groove has a profile that matches the outer surface of the housing, and the gap matches the finger holder, allowing the finger holder to be embedded in the gap for fixation.

[0015] In one embodiment of the present invention, a plurality of gaps are arranged at intervals along the length direction of the fixing seat.

[0016] In one embodiment of the present invention, a second through slot adapted to the clamping knob is provided between adjacent gaps along the length direction of the fixing seat, and the fixing seat and the fixing portion of the pressing plate are connected via the clamping knob penetrating the first through slot and the second through slot;

[0017] The clamping knob can apply pressure to the pressure plate, thereby preventing the syringe from moving in its radial direction.

[0018] In the present invention, syringes of different sizes can be placed in the groove in the middle of the fixing seat, and the position of the syringe can be flexibly adjusted by adjusting the clamping position of the finger frame and the gap in the axial direction of the syringe.

[0019] In one embodiment of the present invention, the bearing seat comprises a first bearing seat and a second bearing seat, the first bearing seat is arranged at the end of the base away from the handwheel, and the second bearing seat is arranged at the end of the base close to the handwheel;

[0020] Wherein, the first bearing seat and the second bearing seat are both fixedly connected to the base.

[0021] In one embodiment of the present invention, the upper surface and the lower surface of the spring pressure plate are in contact with the inner wall of the base, a through hole is provided at the center of the spring pressure plate, an external thread is provided at the position where the screw rod is connected to the spring pressure plate, and an internal thread matching the external thread is provided on the inner wall of the through hole;

[0022] When the handwheel rotates, the lead screw is driven to rotate. Since the lead screw is threadedly connected to the spring pressure plate, the rotation of the lead screw is converted into the movement of the spring pressure plate along the axial direction of the lead screw, thereby being able to adjust the compression amount of the main spring.

[0023] In one embodiment of the present invention, the hand wheel and the screw rod are selected from one of a chimeric connection and an integrated connection.

[0024] In one embodiment of the present invention, the base is provided with a guide hole running through the length direction thereof, the movable seat is allowed to move along the guide hole, and the top of the movable seat is allowed to extend out of the guide hole to be connected with the push rod.

[0025] In one embodiment of the present invention, the push rod includes an integrated transverse rod and a vertical rod, the transverse rod is arranged on a side of the moving seat close to the hand wheel, and one end of the transverse rod is connected to the moving seat by a bolt, and the vertical rod is arranged at the end of the transverse rod away from the moving seat and extends in a direction away from the base;

[0026] When in use, the middle position of the vertical rod on one side close to the first bearing seat abuts against the piston.

[0027] In one embodiment of the present invention, the upper portion of the vertical rod can be manually pulled to reset the position of the push rod in its moving direction.

[0028] In one embodiment of the present invention, one end of the auxiliary spring is hingedly connected to the moving seat, and the other end is hingedly connected to the base.

[0029] In one embodiment of the present invention, a first bearing is symmetrically arranged at a position where the first bearing seat is connected to the screw rod, and a retaining ring is arranged on a side of the first bearing away from the main spring;

[0030] A first boss structure matched with a retaining ring is arranged at the position where the screw rod is connected to the first bearing seat; the cooperation between the retaining ring and the first boss structure can prevent the screw rod from moving along its axial direction.

[0031] In one embodiment of the present invention, a second bearing is symmetrically arranged at the position where the second bearing seat is connected to the screw rod, and a second boss structure adapted to the second bearing is arranged at the position where the screw rod is connected to the second bearing seat; the cooperation between the second bearing and the second boss structure can prevent the screw rod from moving along its axial direction.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The passive injection pump with adjustable thrust provided by the present invention does not need to be connected to any power supply or battery, and can provide a constant thrust for the syringe, effectively increasing the application scenario range and accuracy of the medical injection pump.

[0034] (2) The constant thrust of the flexible mechanism assembly in the passive injection pump with adjustable thrust provided by the present invention can be manually adjusted to adapt to different usage requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic structural diagram of a passive injection pump and a syringe with adjustable thrust according to the present invention;

[0036] Figure 2 It is a schematic structural diagram of a fixed component and a syringe in a passive injection pump with adjustable thrust of the present invention;

[0037] Figure 3 A side view of a fixing seat in a passive injection pump with adjustable thrust according to the present invention;

[0038] Figure 4 It is a structural schematic diagram of a flexible mechanism component (including a base) in a passive injection pump with adjustable thrust of the present invention;

[0039] Figure 5 It is a structural schematic diagram of a flexible mechanism component (excluding a base) in a passive injection pump with adjustable thrust of the present invention;

[0040] Figure 6 It is a cross-sectional view of a flexible mechanism component in a passive injection pump with adjustable thrust of the present invention;

[0041] Figure 7 This is an enlarged view of point A in Figure 6;

[0042] Figure 8 It is a structural schematic diagram of an auxiliary spring and a movable seat in a passive injection pump with adjustable thrust of the present invention;

[0043] Fig. 9 It is a schematic structural diagram of a push rod in a passive injection pump with adjustable thrust according to the present invention;

[0044] Fig.10 It is a structural schematic diagram of a spring pressure plate in a passive injection pump with adjustable thrust of the present invention;

[0045] Fig.11 A simplified schematic diagram of the forces acting on a flexible mechanism component in a passive injection pump with adjustable thrust according to the present invention;

[0046] Fig.12 It is a schematic diagram of the principle of constant adjustable thrust output in a flexible mechanism component in a passive injection pump with adjustable thrust of the present invention;

[0047] Numbers in the figure: 100, syringe; 101, shell; 1011, injection head; 1012, finger holder; 102, piston; 200, fixing assembly; 201, fixing seat; 202, pressure plate; 203, clamping knob; 204, second through groove; 205, gap; 300, flexible mechanism assembly; 301, base; 302, first bearing seat; 303, second bearing seat; 304, first bearing; 305, screw rod; 306, retaining ring; 307, hand wheel; 308, moving seat; 309, push rod; 3091, horizontal rod; 3092, vertical rod; 310, main spring; 311, spring pressure plate; 312, auxiliary spring; 313, second bearing. DETAILED DESCRIPTION

[0048] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0051] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0052] Example 1

[0053] This embodiment provides a passive injection pump with adjustable thrust, which is matched with a syringe 100 when in use. The syringe 100 includes a housing 101 and a piston 102. A finger holder 1012 is provided at one end of the housing 101, and an injection head 1011 is provided at the other end. The piston 102 is provided in the inner cavity of the housing 101 and is allowed to move along the inner cavity of the housing 101. Figures 1 to 10 As shown, the passive injector 100 includes a fixing assembly 200 for fixing the housing 101 and a flexible mechanism assembly 300 for adjusting the thrust, wherein the flexible mechanism assembly 300 includes a base 301, bearing seats arranged on both sides of the base 301, a screw rod 305, a moving seat 308, a main spring 310, an auxiliary spring 312 and a spring pressure plate 311 arranged in the base 301, and a push rod 309 and a hand wheel 307 arranged outside the base 301;

[0054] The fixing assembly 200 is arranged on the upper surface of the base 301, the screw rod 305 passes through the bearing seat, the movable seat 308 and the main spring 310 are sleeved on the outside of the screw rod, and the movable seat 308 allows axial movement along the screw rod 305 to adjust the compression amount of the main spring 310; the spring pressure plate 311 is threadedly connected to the screw rod 305 and is arranged on the side of the main spring 310 away from the movable seat 308, and the hand wheel 307 is arranged at the end of the screw rod 305 close to the spring pressure plate 311, which is used to drive the screw rod 305 to rotate and control The position of the control spring pressure plate 311 controls the preload force of the main spring 310 and thus provides thrust for the moving seat 308; the auxiliary spring 312 is arranged on both sides of the moving seat 308, one end of which is hingedly connected to the moving seat 308, and the other end of which is hingedly connected to the base 301, for providing a flexible thrust for the moving seat 308; the push rod 309 is arranged on the upper surface of the base 301, and the bottom is connected to the moving seat 308, and the push rod 309 is in contact with the piston 102, for driving the piston 102 to move along the length direction of the screw rod 305.

[0055] Furthermore, the fixing assembly 200 includes a fixing seat 201, a pressing plate 202 and a pressing knob 203; the fixing seat 201 is arranged on the upper surface of the base 301, and the upper surface of the fixing seat 201 is provided with a groove for accommodating the housing 101; the two sides of the groove are symmetrically provided with gaps 205 for fixing the finger holder 1012 (to prevent the syringe 100 from moving along its axial direction), and a plurality of gaps 205 are arranged at intervals along the length direction of the fixing seat 201; the pressing plate 202 includes an integrated fixing portion and a pressing portion, The fixing portion is arranged at the end of the pressing portion, and the fixing portion is provided with a first through groove penetrating the fixing portion and adapted to the clamping knob 203. Along the length direction of the fixing seat 201, a second through groove 204 adapted to the clamping knob 203 is provided between adjacent gaps 205. The fixing portion of the fixing seat 201 and the pressing plate 202 are connected via the clamping knob 203 penetrating the first through groove and the second through groove 204; wherein the clamping knob 203 can apply pressure to the pressing plate 202, thereby preventing the syringe 100 from moving in its radial direction.

[0056] Furthermore, the groove has a profile that matches the outer surface of the housing 101 , and the slit 205 matches the finger holder 1012 , allowing the finger holder 1012 to be embedded in the slit 205 for fixation.

[0057] Furthermore, the bearing seat includes a first bearing seat 302 and a second bearing seat 303, the first bearing seat 302 is arranged at the end of the base 301 away from the handwheel 307, and the second bearing seat 303 is arranged at the end of the base 301 close to the handwheel 307; wherein the first bearing seat 302 and the second bearing seat 303 are both fixedly connected to the base 301.

[0058] Furthermore, the upper surface and the lower surface of the spring pressure plate 311 are in contact with the inner wall of the base 301, a through hole is provided at the center position of the spring pressure plate 311, an external thread is provided at the position where the screw rod 305 is connected to the spring pressure plate 311, and an internal thread matching the external thread is provided on the inner wall of the through hole; when the handwheel 307 rotates, the screw rod 305 is driven to rotate, and since the screw rod 305 is threadedly connected to the spring pressure plate 311, the rotation of the screw rod 305 will be converted into the axial movement of the spring pressure plate 311 along the screw rod 305, thereby being able to adjust the compression amount of the main spring 310.

[0059] Furthermore, the hand wheel 307 and the screw rod 305 are selected from one of a chimeric connection and an integrated connection.

[0060] Furthermore, the base 301 is provided with a guide hole running through the length direction thereof, and the movable seat 308 is allowed to move along the guide hole, and the top of the movable seat 308 is allowed to extend out of the guide hole to be connected with the push rod 309 .

[0061] Furthermore, the push rod 309 includes an integrated transverse rod 3091 and a vertical rod 3092. The transverse rod 3091 is arranged on the side of the movable seat 308 close to the hand wheel 307, and one end thereof is connected to the movable seat 308 by a bolt. The vertical rod 3092 is arranged at the end of the transverse rod 3091 away from the movable seat 308 and extends in a direction away from the base 301; when in use, the vertical rod 3092 abuts against the piston 102 at the middle position on the side close to the first bearing seat 302.

[0062] Furthermore, the upper portion of the vertical rod 3092 can be manually pulled to reset the position of the push rod 309 (the vertical rod 3092 and the transverse rod 3091 ) in the direction of its movement.

[0063] Furthermore, one end of the auxiliary spring 312 is hingedly connected to the movable seat 308 , and the other end is hingedly connected to the base 301 .

[0064] Furthermore, the first bearing 304 is symmetrically arranged at the position where the first bearing seat 302 is connected to the screw rod 305, and a retaining ring 306 is arranged on the side of the first bearing 304 away from the main spring 310; the position where the screw rod 305 is connected to the first bearing seat 302 is provided with a first boss structure adapted to the retaining ring 306; the cooperation between the retaining ring 306 and the first boss structure can prevent the screw rod 305 from moving along its axial direction;

[0065] A second bearing 313 is symmetrically arranged at the position where the second bearing seat 303 is connected to the screw rod 305, and a second boss structure adapted to the second bearing 313 is arranged at the position where the screw rod 305 is connected to the second bearing seat 303; the cooperation between the second bearing 313 and the second boss structure can prevent the screw rod 305 from moving along its axial direction.

[0066] When in use, the syringe 100 is placed on the fixed seat 201 (the shell 101 is close to the groove, and the finger holder 1012 is stuck in one of the gaps 205 on the fixed seat 201, which can be adjusted according to actual conditions) to achieve axial fixation of the syringe 100; then the pressure plate 202 is set on the upper surface of the syringe 100, and then the clamping knob 203 is used to penetrate the first through groove and the second through groove 204 to achieve radial fixation of the syringe 100; then the flexible mechanism assembly 300 can be used to adjust the thrust size (artificially adjust the vertical rod 3092 along the axial position of the screw rod 305 to achieve compression of the main spring 310, or use the hand wheel 307 to adjust the position of the spring pressure plate 311 to achieve pre-tightening of the main spring 310).

[0067] Example 2

[0068] The working principle of the flexible mechanism assembly 300 is as follows: Fig.11 and Fig.12As shown. In this schematic diagram, the core components of the flexible mechanism assembly 300 are a main spring 310 and two symmetrically arranged auxiliary springs 312, and include components such as a spring pressure plate 311, a base 301, and a moving seat 308. The main spring 310 is installed between the moving seat 308 and the spring pressure plate 311, and the two ends of the auxiliary spring 312 are hinged on the moving seat 308 and the base 301, respectively. The moving seat 308 is used to output the thrust of the flexible mechanism assembly 300, and can move in the movement direction of the moving seat 308 under the action of an external force f and compress the main spring 310 and the auxiliary spring 312. In addition, the position of the spring pressure plate 311 in the movement direction of the moving seat 308 can be adjusted to adjust the preload of the main spring 310. For the convenience of representation, it is assumed that the moving direction of the moving seat 308 is the vertical direction, the position where the auxiliary spring 312 is hinged to the base 301 is defined as 0, the position of the moving seat 308 is represented as a variable h, and the movable area of ​​the moving seat 308 is set to h∈[-h0,h0]. Both the main spring 310 and the auxiliary spring 312 are linear springs, and the force f1 of the main spring 310 can be expressed as:

[0069] f1=k1(l1-b-h0-h);

[0070] Where k1 represents the stiffness coefficient of the main spring 310, l1 represents its original length, and the distance between the spring pressure plate 311 and the lowest point h=-h0 of the moving seat 308 is represented by b. This parameter can be used to adjust the preload force of the main spring 310. The force of the main spring 310 increases linearly during its compression, such as Fig.12 As the movable seat 308 moves downward, the forces and inclination angles θ of the two auxiliary springs 312 will change, wherein the forces in the horizontal direction cancel each other out, and the forces in the vertical direction are superimposed on each other, so the resultant force f2 of the auxiliary springs 312 can be expressed as:

[0071]

[0072] Where k2 is the stiffness coefficient of the auxiliary spring 312, l2 represents its original length, and a is the horizontal distance between the hinge points at both ends of the auxiliary spring 312. The combined force of the main spring 310 increases first and then decreases during the downward movement of the moving seat 308. Fig.12 In the vertical direction, the thrust f output by the moving seat 308 is c The force of the main spring 310 and the auxiliary spring 312 is added together to obtain:

[0073] f c =f1+f2

[0074] By setting appropriate parameters, the flexible mechanism assembly 300 can output approximately constant thrust within the working area h∈[-h0,h0], such as Fig.12In addition to the constant force output characteristic, the flexible mechanism assembly 300 can also adjust the magnitude of the output force. Fig.12 Three different main spring 310 preload forces are set, and the corresponding main spring 310 forces are f1', f1" and f1"' respectively. By superimposing these different main spring 310 forces and the auxiliary spring 312 force f2, different amplitudes and approximately constant thrust f can be obtained in the working area of ​​the moving seat 308. c '、f c ” and f c It is worth noting that, since adjusting the preload force of the main spring 310 will not affect the force output accuracy of the main spring 310, it will not affect the output accuracy of the resultant force.

[0075] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the explanation of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A passive injection pump with adjustable thrust, adapted to be used with a syringe (100), wherein the syringe (100) comprises a housing (101) and a piston (102), wherein one end of the housing (101) is provided with a finger holder (1012), and the other end is provided with an injection head (1011), wherein the piston (102) is arranged in the inner cavity of the housing (101) and is allowed to move along the inner cavity of the housing (101); characterized in that: The passive injector (100) comprises a fixing component (200) for fixing the housing (101) and a flexible mechanism component (300) for adjusting the thrust. The flexible mechanism assembly (300) comprises a base (301), bearing seats arranged on both sides of the base (301), a screw rod (305), a moving seat (308), a main spring (310), an auxiliary spring (312) and a spring pressure plate (311) arranged inside the base (301), and a push rod (309) and a hand wheel (307) arranged outside the base (301); The fixing assembly (200) is arranged on the upper surface of the base (301), the screw (305) passes through the bearing seat, the movable seat (308) and the main spring (310) are sleeved on the outside of the screw, and the movable seat (308) allows axial movement along the screw (305) to adjust the compression of the main spring (310); the spring pressure plate (311) is threadedly connected to the screw (305) and is arranged on a side of the main spring (310) away from the movable seat (308); the hand wheel (307) is arranged at the end of the screw (305) close to the spring pressure plate (311), and is used to drive the screw (305) to rotate and The position of the spring pressure plate (311) is controlled, and the preload force of the main spring (310) is controlled to provide thrust for the moving seat (308); the auxiliary spring (312) is arranged on both sides of the moving seat (308), one end of which is hingedly connected to the moving seat (308), and the other end of which is hingedly connected to the base (301), and is used to provide flexible thrust for the moving seat (308); the push rod (309) is arranged on the upper surface of the base (301), and the bottom is connected to the moving seat (308), and the push rod (309) is in contact with the piston (102), and is used to drive the piston (102) to move along the length direction of the screw rod (305).

2. The passive injection pump with adjustable thrust according to claim 1, characterized in that: The fixing assembly (200) comprises a fixing seat (201), a pressing plate (202) and a pressing knob (203); The fixing seat (201) is arranged on the upper surface of the base (301), and the upper surface of the fixing seat (201) is provided with a groove for accommodating the housing (101); gaps (205) for fixing the finger holder (1012) are symmetrically arranged on both sides of the groove; The pressure plate (202) comprises an integrated fixing portion and a holding portion; the fixing portion is arranged at the end of the holding portion, and the fixing portion is provided with a first through groove penetrating the fixing portion and adapted to the clamping knob (203); the first through groove allows for active connection with the clamping knob (203), and cooperates with the fixing seat (201) to achieve fixation of the housing (101).

3. The passive injection pump with adjustable thrust according to claim 2, characterized in that: The groove has a profile that matches the outer surface of the housing (101), and the slit (205) matches the finger holder (1012), allowing the finger holder (1012) to be embedded in the slit (205) for fixation.

4. The passive injection pump with adjustable thrust according to claim 2, characterized in that: Along the length direction of the fixing seat (201), a plurality of gaps (205) are arranged at intervals.

5. The passive injection pump with adjustable thrust according to claim 4, characterized in that: Along the length direction of the fixing seat (201), a second through slot (204) adapted to the clamping knob (203) is provided between adjacent gaps (205), and the fixing seat (201) and the fixing portion are connected via the clamping knob (203) penetrating the first through slot and the second through slot (204).

6. The passive injection pump with adjustable thrust according to claim 1, characterized in that: The bearing seat comprises a first bearing seat (302) and a second bearing seat (303), wherein the first bearing seat (302) is arranged at an end of the base (301) away from the hand wheel (307), and the second bearing seat (303) is arranged at an end of the base (301) close to the hand wheel (307); Wherein, the first bearing seat (302) and the second bearing seat (303) are both fixedly connected to the base (301).

7. The passive injection pump with adjustable thrust according to claim 1, characterized in that: The upper surface and the lower surface of the spring pressure plate (311) are in contact with the inner wall of the base (301), a through hole is provided at the center of the spring pressure plate (311), an external thread is provided at the position where the screw rod (305) is connected to the spring pressure plate (311), and an internal thread matching the external thread is provided on the inner wall of the through hole.

8. The passive injection pump with adjustable thrust according to claim 7, characterized in that: The hand wheel (307) and the screw rod (305) are selected from one of a chimeric connection and an integrated connection.

9. The passive injection pump with adjustable thrust according to claim 1, characterized in that: The base (301) is provided with a guide hole running through the length direction thereof, and the top of the movable seat (308) is allowed to extend out of the guide hole to be connected with the push rod (309).

10. The passive injection pump with adjustable thrust according to claim 9, characterized in that: The push rod (309) includes an integrated transverse rod (3091) and a vertical rod (3092). The transverse rod (3091) is arranged on a side of the movable seat (308) close to the hand wheel (307), and one end thereof is connected to the movable seat (308) by a bolt. The vertical rod (3092) is arranged at the end of the transverse rod (3091) away from the movable seat (308) and extends in a direction away from the base (301).

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