Passive injection pump capable of adjusting thrust

Abstract

The utility model 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] This utility model relates to the field of medical device technology, and in particular to a passive injection pump with adjustable thrust. Background Technology

[0002] Typically, when administering intravenous injections to patients, healthcare professionals can use medical infusion pumps in addition to traditional manual methods to more precisely control the injection process. The main function of an infusion pump is to output linear motion power, thereby driving the syringe piston. Infusion pumps currently on the market can be divided into two types: active and passive.

[0003] Active infusion pumps require a power source (such as a battery or AC power) to drive internal actuators (such as motors), which in turn propel the syringe piston via a transmission mechanism. For example, Chinese Utility Model Patent CN 117357733A describes a medical infusion pump that uses electricity to drive its actuators and can switch to manual injection mode in emergencies. Furthermore, Chinese Utility Model Patent CN 115920175A describes a medical infusion pump that uses a motor to output power. To reduce the impact of motor rotational inertia on injection accuracy during shutdown, an electromagnetic clutch is used to reduce the impact of motor inertia, thereby improving the pump's accuracy. Similarly, Chinese Utility Model Patent CN 115887835A describes an active medical infusion pump that can be used in low-temperature environments. However, active medical infusion pumps are power-dependent and cannot be used in environments without power (such as sudden power outages caused by earthquakes, storms, or during fieldwork) or certain special environments (such as the strong magnetic field environment of MRI).

[0004] Passive infusion pumps operate without an external power source. These devices typically utilize springs, gravity, or other mechanical principles to apply pressure to the syringe piston, propelling the medication flow. For example, Chinese Utility Model Patent CN 103536987A describes a passive automatic drug injection holder that uses a push plate, springs, and other components to move the syringe piston. Similarly, Chinese Utility Model Patent CN2098291U describes a medical intravenous injection pusher that also uses springs to move the syringe piston. However, these devices all employ single or multiple springs arranged in parallel to move the syringe piston. The thrust inevitably varies with the spring length, causing the thrust on the syringe piston to gradually decrease during injection. This results in significant pressure fluctuations within the syringe, exacerbating patient discomfort. Furthermore, existing passive infusion pump designs suffer from difficulties in precisely adjusting the thrust on the syringe piston, hindering accurate control of drug delivery rate and dosage. This is particularly problematic in treatment scenarios requiring long-term stable infusion or extremely high dosage accuracy, potentially severely impacting treatment efficacy.

[0005] Therefore, it is crucial to develop an injection pump that can solve the aforementioned technical problems. Utility Model Content

[0006] To address the problems of large thrust fluctuations and difficulty in fine-tuning existing passive syringe pumps, the purpose of this invention is to provide a passive syringe pump with adjustable thrust. This invention's passive syringe features a flexible mechanism with a constant and adjustable thrust to reduce pressure fluctuations within the syringe, thereby achieving precise adjustment of the syringe thrust.

[0007] The objective of this utility model can be achieved through the following technical solutions:

[0008] This invention provides a passive injection pump with adjustable thrust, which is adapted to a syringe during use. The syringe includes a housing and a piston. A finger holder is provided at one end of the housing, and an injection head is provided at the other end. The piston is disposed within the inner cavity of the housing and is allowed to move along the inner cavity. The passive syringe includes 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 on both sides of the base, a lead screw, a movable seat, a main spring, an auxiliary spring and a spring pressure plate disposed within the base, and a push rod and a handwheel disposed outside the base.

[0010] The fixed assembly is located 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. The movable seat allows movement along the axial direction of the lead screw to adjust the compression of the main spring. The spring pressure plate is threaded to the lead screw and is located on the side of the main spring away from the movable seat. The handwheel is located at the end of the lead screw near the spring pressure plate and is used to drive the lead screw to rotate and control the position of the spring pressure plate, thereby controlling the preload of the main spring and providing thrust to the movable seat. The auxiliary spring is located on both sides of the movable seat, with one end hinged to the movable seat and the other end hinged to the base, and is used to provide flexible thrust to the movable seat. The push rod is located on the upper surface of the base and connected to the movable seat at the bottom. The push rod abuts against the piston and is used to drive the piston to move along the length of the lead screw.

[0011] In one embodiment of this utility model, the fixing component includes a fixing base, a pressure plate, and a clamping knob;

[0012] The fixing seat is disposed on the upper surface of the base, and the upper surface of the fixing seat is provided with a groove for accommodating the shell; slits for fixing the finger bracket are symmetrically arranged on both sides of the groove.

[0013] The pressure plate includes an integrated fixing part and a pressing part; the fixing part is disposed at the end of the pressing part, and the fixing part is provided with a first through groove that penetrates the fixing part and is adapted to the pressing knob. The first through groove allows for movable connection with the pressing knob, and the cooperation with the fixing seat realizes the fixing of the housing.

[0014] In one embodiment of this utility model, 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 this utility model, a plurality of slits are provided at intervals along the length of the fixing seat.

[0016] In one embodiment of this utility model, a second through groove adapted to the clamping knob is provided between adjacent gaps along the length direction of the fixing seat, and the fixing part of the fixing seat and the pressure plate is connected by a clamping knob passing through the first through groove and the second through groove.

[0017] The clamping knob applies pressure to the pressure plate, thereby preventing the syringe from moving radially.

[0018] In this invention, syringes of different sizes can be placed in the groove in the middle of the fixed base, and the position of the syringe can be flexibly adjusted in the axial direction of the syringe by adjusting the snap-fit ​​position of the finger holder with the gap.

[0019] In one embodiment of the present invention, the bearing housing includes a first bearing housing and a second bearing housing, wherein the first bearing housing is disposed at the end of the base away from the handwheel, and the second bearing housing is disposed at the end of the base close to the handwheel;

[0020] Both the first bearing housing and the second bearing housing are fixedly connected to the base.

[0021] In one embodiment of this utility model, the upper and lower surfaces 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 lead screw connects to the spring pressure plate, and an internal thread adapted to the external thread is provided on the inner wall of the through hole.

[0022] When the handwheel rotates, it drives the lead screw 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 axis of the lead screw, which in turn can control the compression of the main spring.

[0023] In one embodiment of this utility model, the handwheel and the lead screw are selected from either a fitted connection or an integrated connection.

[0024] In one embodiment of this utility model, the base is provided with a guide hole extending through its length, 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 and connect with the push rod.

[0025] In one embodiment of this utility model, the push rod includes an integrated horizontal rod and a vertical rod. The horizontal rod is disposed on the side of the movable seat near the handwheel, and one end of the horizontal rod is connected to the movable seat by a bolt. The vertical rod is disposed at the end of the horizontal rod away from the movable seat and extends in a direction away from the base.

[0026] In use, the vertical rod abuts against the piston at the middle position on the side closest to the first bearing seat.

[0027] In one embodiment of this utility model, the upper part of the vertical rod can be manually pulled to reset the position of the push rod in its direction of movement.

[0028] In one embodiment of this utility model, one end of the auxiliary spring is hinged to the movable seat, and the other end is hinged to the base.

[0029] In one embodiment of this utility model, a first bearing is symmetrically arranged at the position where the first bearing seat is connected to the lead screw, and a retaining ring is arranged on the side of the first bearing away from the main spring.

[0030] The lead screw is provided with a first boss structure that is adapted to the retaining ring at the position where it connects to the first bearing seat; the cooperation between the retaining ring and the first boss structure can prevent the lead screw from moving along its axial direction.

[0031] In one embodiment of this utility model, a second bearing is symmetrically arranged at the position where the second bearing housing is connected to the lead screw, and a second boss structure adapted to the second bearing is provided at the position where the lead screw is connected to the second bearing housing; the cooperation between the second bearing and the second boss structure can prevent the lead screw from moving along its axial direction.

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

[0033] (1) The adjustable thrust passive injection pump provided by this utility model does not require any power supply or battery, and can provide a constant thrust for the syringe, effectively increasing the application range and accuracy of the medical injection pump.

[0034] (2) The constant thrust of the flexible mechanism component in the adjustable thrust passive injection pump provided by this utility model can be manually adjusted to adapt to different usage requirements. Attached Figure Description

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

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

[0037] Figure 3 This is a side view of the fixed base in a passive injection pump with adjustable thrust according to the present invention.

[0038] Figure 4 This is a structural schematic diagram of the flexible mechanism component (including base) in a passive injection pump with adjustable thrust according to this utility model;

[0039] Figure 5 This is a schematic diagram of the flexible mechanism component (excluding the base) in a passive injection pump with adjustable thrust according to this utility model;

[0040] Figure 6 This is a cross-sectional view of the flexible mechanism component in a passive injection pump with adjustable thrust according to this utility model.

[0041] Figure 7 This is a magnified view of point A in section 6 of the diagram;

[0042] Figure 8 This is a schematic diagram of the auxiliary spring and movable seat in a passive injection pump with adjustable thrust according to this utility model;

[0043] Figure 9This is a schematic diagram of the push rod structure in a passive injection pump with adjustable thrust according to this utility model;

[0044] Figure 10 This is a schematic diagram of the spring pressure plate in a passive injection pump with adjustable thrust according to this utility model;

[0045] Figure 11 A simplified force diagram of the flexible mechanism component in an adjustable thrust passive injection pump according to this utility model;

[0046] Figure 12 This is a schematic diagram illustrating the constant adjustable thrust output principle of the flexible mechanism component in an adjustable thrust passive injection pump according to this utility model.

[0047] The following are the labeling elements in the diagram: 100, syringe; 101, housing; 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, lead screw; 306, retaining ring; 307, handwheel; 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 Implementation

[0048] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0049] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0050] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0051] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0052] Example 1

[0053] This embodiment provides a passive injection pump with adjustable thrust, which is adapted to a syringe 100 during use. The syringe 100 includes a housing 101 and a piston 102. A finger rest 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 disposed in the inner cavity of the housing 101 and is allowed to move along the inner cavity of the housing 101. Figures 1-10 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. The flexible mechanism assembly 300 includes a base 301, bearing seats disposed on both sides of the base 301, a lead screw 305, a moving seat 308, a main spring 310, an auxiliary spring 312 and a spring pressure plate 311 disposed in the base 301, and a push rod 309 and a handwheel 307 disposed on the outside of the base 301.

[0054] The fixing component 200 is disposed on the upper surface of the base 301. The lead screw 305 passes through the bearing seat. The movable seat 308 and the main spring 310 are sleeved on the outside of the lead screw. The movable seat 308 allows axial movement along the lead screw 305 to adjust the compression of the main spring 310. The spring pressure plate 311 is threadedly connected to the lead screw 305 and disposed on the side of the main spring 310 away from the movable seat 308. The handwheel 307 is disposed at the end of the lead screw 305 near the spring pressure plate 311, and is used to drive the lead screw 305 to rotate and control its rotation. The position of the spring pressure plate 311 controls the preload of the main spring 310, thereby providing thrust to the movable seat 308; the auxiliary spring 312 is disposed on both sides of the movable seat 308, with one end hinged to the movable seat 308 and the other end hinged to the base 301, for providing flexible thrust to the movable seat 308; the push rod 309 is disposed on the upper surface of the base 301, with its bottom connected to the movable seat 308, and the push rod 309 abuts against the piston 102, for driving the piston 102 to move along the length direction of the lead screw 305.

[0055] Furthermore, the fixing assembly 200 includes a fixing base 201, a pressure plate 202, and a clamping knob 203; the fixing base 201 is disposed on the upper surface of the base 301, and the upper surface of the fixing base 201 is provided with a groove for accommodating the housing 101; slits 205 for fixing the finger holder 1012 (preventing the syringe 100 from moving along its axial direction) are symmetrically arranged on both sides of the groove, and several slits 205 are spaced apart along the length direction of the fixing base 201; the pressure plate 202 includes an integrated fixing part and a clamping part. The fixing part is provided at the end of the holding part. The fixing part is provided with a first through groove that penetrates the fixing part and is 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 part of the fixing seat 201 and the pressure plate 202 are connected by the clamping knob 203 that penetrates the first through groove and the second through groove 204. The clamping knob 203 can apply pressure to the pressure plate 202, thereby preventing the syringe 100 from moving radially.

[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 housing includes a first bearing housing 302 and a second bearing housing 303. The first bearing housing 302 is disposed at the end of the base 301 away from the handwheel 307, and the second bearing housing 303 is disposed at the end of the base 301 close to the handwheel 307. Both the first bearing housing 302 and the second bearing housing 303 are fixedly connected to the base 301.

[0058] Furthermore, the upper and lower surfaces 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 lead screw 305 connects to the spring pressure plate 311. An internal thread that matches the external thread is provided on the inner wall of the through hole. When the handwheel 307 rotates, it drives the lead screw 305 to rotate. Since the lead screw 305 is threadedly connected to the spring pressure plate 311, the rotation of the lead screw 305 is converted into the movement of the spring pressure plate 311 along the axial direction of the lead screw 305, thereby controlling the compression of the main spring 310.

[0059] Furthermore, the handwheel 307 and the lead screw 305 are selected from either a mating connection or an integrated connection.

[0060] Furthermore, the base 301 is provided with a guide hole extending through its length, 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 and connect with the push rod 309.

[0061] Furthermore, the push rod 309 includes an integrated horizontal rod 3091 and a vertical rod 3092. The horizontal rod 3091 is disposed on the side of the movable seat 308 near the handwheel 307, and one end of it is connected to the movable seat 308 by bolts. The vertical rod 3092 is disposed at the end of the horizontal rod 3091 away from the movable seat 308 and extends in a direction away from the base 301. In use, the middle position of the vertical rod 3092 near the first bearing seat 302 abuts against the piston 102.

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

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

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

[0065] A second bearing 313 is symmetrically provided at the position where the second bearing housing 303 is connected to the lead screw 305. A second boss structure adapted to the second bearing 313 is provided at the position where the lead screw 305 is connected to the second bearing housing 303. The cooperation between the second bearing 313 and the second boss structure can prevent the lead screw 305 from moving along its axial direction.

[0066] In use, the syringe 100 is placed on the fixed base 201 (the housing 101 is tightly fitted into the groove, and the finger holder 1012 is locked in one of the gaps 205 on the fixed base 201, which can be adjusted according to the actual situation) to fix the syringe 100 axially; then the pressure plate 202 is set on the upper surface of the syringe 100, and the pressure knob 203 is used to pass through the first through groove and the second through groove 204 to fix the syringe 100 radially; then the force can be adjusted by using the flexible mechanism component 300 (the main spring 310 is compressed by manually adjusting the position of the vertical rod 3092 along the axial direction of the lead screw 305, or the main spring 310 is pre-tightened by adjusting the position of the spring pressure plate 311 using the handwheel 307).

[0067] Example 2

[0068] The working principle of the flexible mechanism component 300 is as follows: Figure 11 and Figure 12 As shown in the schematic diagram, the core components of the flexible mechanism assembly 300 are a main spring 310 and two symmetrically arranged auxiliary springs 312, and it also includes components such as a spring pressure plate 311, a base 301, and a movable seat 308. The main spring 310 is installed between the movable seat 308 and the spring pressure plate 311, and the two ends of the auxiliary springs 312 are hinged to the movable seat 308 and the base 301, respectively. The movable seat 308 is used to output the thrust of the flexible mechanism assembly 300. Under the action of an external force f, it can move in the direction of movement of the movable seat 308 and compress the main spring 310 and the auxiliary springs 312. In addition, the position of the spring pressure plate 311 in the direction of movement of the movable seat 308 can be adjusted, thereby adjusting the preload of the main spring 310. For ease of representation, assume the movement direction of the movable seat 308 is vertical. Define the hinge position of the auxiliary spring 312 to the base 301 as 0, and the position of the movable seat 308 as the variable h. The movable region of the movable seat 308 is set as h∈[-h0,h0]. Both the main spring 310 and the auxiliary spring 312 are linear springs. 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 b represents the distance between the spring pressure plate 311 and the lowest point h = -h0 of the moving seat 308. This parameter can be used to adjust the preload of the main spring 310. The force of the main spring 310 increases linearly during its compression process, such as... Figure 12 As shown in f1'. During the downward movement of the movable seat 308, the forces and tilt angles θ of the two auxiliary springs 312 change. The horizontal components cancel each other out, while the vertical components add up. Therefore, 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 resultant force of the main spring 310 first increases and then decreases during the downward movement of the moving seat 308, as follows: Figure 12 As shown in f2, the thrust f output by the movable seat 308 in the vertical direction is... c The result is obtained by the superposition of the forces of the main spring 310 and the auxiliary spring 312:

[0073] f c =f1+f2

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

[0075] The above description of the embodiments is provided to enable those skilled in the art to understand and use the utility model. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present utility model is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the interpretation of the present utility model without departing from its scope should be within the protection scope of the present utility model.

Claims

1. A passive injection pump with adjustable thrust, adapted to use with a syringe (100), the syringe (100) comprising a housing (101) and a piston (102), wherein a finger holder (1012) is provided at one end of the housing (101) and an injection head (1011) is provided at the other end, and the piston (102) is disposed within the cavity of the housing (101) and allowed to move along the cavity of the housing (101); characterized in that, The syringe (100) includes a fixing assembly (200) for fixing the housing (101) and a flexible mechanism assembly (300) for adjusting the thrust. The flexible mechanism assembly (300) includes a base (301), bearing seats disposed on both sides of the base (301), a lead screw (305), a movable seat (308), a main spring (310), an auxiliary spring (312) and a spring pressure plate (311) disposed in the base (301), and a push rod (309) and a handwheel (307) disposed on the outside of the base (301); The fixing component (200) is disposed on the upper surface of the base (301), the lead screw (305) passes through the bearing seat, the movable seat (308) and the main spring (310) are sleeved on the outside of the lead screw, the movable seat (308) allows axial movement along the lead screw (305) to adjust the compression of the main spring (310); the spring pressure plate (311) is threadedly connected to the lead screw (305) and disposed on the side of the main spring (310) away from the movable seat (308), the handwheel (307) is disposed at the end of the lead screw (305) near the spring pressure plate (311) for driving the lead screw (305) to rotate and The position of the spring pressure plate (311) is controlled to control the preload of the main spring (310) and thus provide thrust to the moving seat (308); the auxiliary spring (312) is set on both sides of the moving seat (308), one end is hinged to the moving seat (308), and the other end is hinged to the base (301) to provide flexible thrust to the moving seat (308); the push rod (309) is set on the upper surface of the base (301), and the bottom is connected to the moving seat (308). The push rod (309) abuts against the piston (102) to drive the piston (102) to move along the length direction of the lead screw (305).

2. The passive injection pump with adjustable thrust according to claim 1, characterized in that, The fixing component (200) includes a fixing base (201), a pressure plate (202), and a clamping knob (203); The fixing seat (201) is disposed 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 shell (101); slits (205) for fixing the finger bracket (1012) are symmetrically arranged on both sides of the groove. The pressure plate (202) includes an integrated fixing part and a pressing part; the fixing part is located at the end of the pressing part, and the fixing part is provided with a first through groove that penetrates the fixing part and is adapted to the pressing knob (203). The first through groove allows for movable connection with the pressing knob (203), and the cooperation with the fixing seat (201) realizes the fixing 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 is adapted to the outer surface of the housing (101), and the slit (205) is adapted to 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 of the fixing seat (201), there are several gaps (205) at intervals.

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

6. The passive injection pump with adjustable thrust according to claim 1, characterized in that, The bearing housing includes a first bearing housing (302) and a second bearing housing (303). The first bearing housing (302) is disposed at the end of the base (301) away from the handwheel (307), and the second bearing housing (303) is disposed at the end of the base (301) close to the handwheel (307). The first bearing housing (302) and the second bearing housing (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 and lower surfaces 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 lead screw (305) connects to the spring pressure plate (311). An internal thread that matches the external thread is provided on the inner wall of the through hole.

8. A passive injection pump with adjustable thrust according to claim 7, characterized in that, The handwheel (307) and the lead screw (305) are selected from either a mating connection or an integrated connection.

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

10. A passive injection pump with adjustable thrust according to claim 9, characterized in that, The push rod (309) includes an integrated horizontal rod (3091) and a vertical rod (3092). The horizontal rod (3091) is located on the side of the movable seat (308) near the handwheel (307), and one end of it is connected to the movable seat (308) by a bolt. The vertical rod (3092) is located at the end of the horizontal rod (3091) away from the movable seat (308) and extends in a direction away from the base (301).

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