Ejection short needle assembly and high-speed injection device

Abstract

The utility model discloses an ejection short needle assembly and a high-speed injection device, which comprise an injection cavity for storing a medium, an ejection short needle assembly and an ejection short needle assembly, wherein the internal pressure of the injection cavity is variable; the ejection valve element is installed in the injection cavity in a sliding mode in a plunger mode, and the short needle head is communicated with the high-pressure end face of the injection cavity through a valve body. When the pressure in the injection cavity is increased, the ejection valve element can move in the first direction; the valve body can be in a communicating state only when the internal pressure of the injection cavity exceeds a set threshold value; or the valve body can be in a communication state only after the displacement of the ejection valve element is larger than the set threshold value, the probability of needle breaking and needle bending can be reduced, the injection depth of liquid medicine is guaranteed, the utilization efficiency of the liquid medicine is improved, the injection efficiency is improved, and the single-time injection time is shortened.

Description

Technical Field

[0001] The utility model relates to the technical field of livestock hygiene and safety, and more specifically, to an ejection short needle assembly. In addition, the utility model also relates to an ejection short needle high-speed injection device including the above ejection short needle assembly. Background Art

[0002] Injection treatment is crucial in the breeding industry and can reduce the death loss of pigs caused by diseases. However, traditional needle injection may cause problems such as broken needles during injection. After injection, the drug accumulates at the injection site, is not easily absorbed, affects the treatment effect, and at the same time, the accumulated drug may cause local inflammation problems.

[0003] The published text of related technology CN 115551574 A discloses a needleless injection method, which realizes needleless injection of liquid medicine through high-speed jet flow, effectively solving problems such as broken needles and bent needles in existing needle injections. However, in actual use in the livestock industry, blocked by the surface fur or dense surface cortex of livestock and poultry, during needleless injection, the penetration ability of the liquid medicine is weak, the liquid medicine mostly concentrates under the skin, and a large amount of liquid medicine remains on the skin surface. The actual utility of the liquid medicine is not high, resulting in serious waste and unable to achieve the purpose of intramuscular injection.

[0004] In summary, how to provide an injection device that can reduce the probability of broken needles and bent needles, ensure the injection depth of the liquid medicine, and improve the utilization efficiency of the liquid medicine is an urgent problem to be solved by those skilled in the art at present. Summary of the Utility Model

[0005] In view of this, the purpose of the utility model is to provide an ejection short needle assembly that can reduce the probability of broken needles and bent needles, ensure the injection depth of the liquid medicine, and improve the utilization efficiency of the liquid medicine.

[0006] Another purpose of the utility model is to provide an ejection short needle injection device including the above ejection short needle assembly, which can improve the injection efficiency and shorten the single injection time.

[0007] To achieve the above purpose, the utility model provides the following technical solutions:

[0008] An ejection short needle assembly, comprising:

[0009] An injection cavity for medium storage, the internal pressure of the injection cavity being variable;

[0010] An ejection valve core slidably installed in the injection cavity in the form of a plunger, and a short needle tip connected to the high-pressure end face of the injection cavity through a valve body;

[0011] When the pressure in the injection cavity increases, the ejection valve core can move in the first direction;

[0012] The valve body can only be in a communicating state when the internal pressure of the injection cavity exceeds a set threshold;

[0013] Or the valve body can only be in a communicating state after the displacement of the ejection valve core is greater than a set threshold.

[0014] Preferably, the valve body is a pressure relief valve.

[0015] Preferably, the pressure relief valve includes: a medicine outlet channel that penetrates the ejection valve core and communicates with the short needle tip, a medicine outlet check valve core for truncating the medicine outlet channel, and a medicine outlet return spring that inhibits the movement and avoidance of the medicine outlet check valve core.

[0016] Preferably, the axes of the medicine outlet channel and the short needle tip overlap, and the medicine outlet return spring can inhibit the medicine outlet check valve core from moving and avoiding along the first movement direction.

[0017] Preferably, it further includes an ejection return spring for inhibiting the displacement of the ejection valve core and enabling the ejection valve core to return to the displacement starting point.

[0018] Preferably, the injection cavity is communicatively provided with a medicine inlet, and a medicine inlet check valve assembly is arranged at the medicine inlet.

[0019] Preferably, an injection valve core is slidably arranged in the injection cavity in the form of a plunger, and an injection push rod for driving the injection valve core to move forward or backward along the first movement direction.

[0020] A high-speed injection device for an ejection short needle, including the above-mentioned ejection short needle assembly, further includes:

[0021] A push rod that changes the pressure in the injection cavity through its own movement;

[0022] A power spring that enables the push rod to move rapidly along the first movement direction by releasing potential energy;

[0023] A driving assembly for driving the push rod to move backward along the first movement direction and increasing the internal elastic potential energy of the power spring.

[0024] Preferably, the driving assembly includes a rotating cam driven by a motor;

[0025] A contact member that is in contact with the spiral slope surface of the rotating cam and is fixed to the end of the push rod;

[0026] There is a vertical transition section between the low point and the high point of the spiral slope surface of the rotating cam.

[0027] Preferably, the contact member includes a rear-end fixing member fixedly arranged at the tail end of the push rod, and a roller rotatably installed in the rear-end fixing member and in rolling contact with the rotary cam.

[0028] Preferably, the ejecting short needle assembly further includes a trigger switch capable of moving reversely along the first movement direction to expose the short needle tip, and a trigger return spring for restraining the movement of the trigger switch and enabling its reset;

[0029] When the trigger switch moves reversely along the first movement direction by more than a set threshold value, it can send an instruction to cause the drive assembly to complete a single-stroke cycle.

[0030] When the ejecting short needle assembly provided by the present utility model is in use, by quickly changing the pressure in the injection cavity, the ejecting valve core in the form of a plunger quickly moves along the first direction, that is, drives the short needle tip to quickly pierce into the injection position, piercing through the surface skin of the injection position, without fear of the interference of the surface fur of the injection position. And when the short needle tip penetrates to a predetermined position, or when the pressure in the injection cavity exceeds the set threshold value, the valve body can be opened, so that the liquid medicine in the injection cavity is quickly ejected in the form of a torrent through the short needle tip, which not only improves the injection speed, but also solves the problem of the accumulation of liquid medicine in the body;

[0031] At the same time, by adopting a short needle tip, compared with needle-free injection, it has stronger skin surface penetration ability, is suitable for livestock injection, and can effectively improve the injection depth, is suitable for intramuscular injection, and reduces the residue of liquid medicine on the skin surface after injection.

[0032] And compared with long needle injection, the penetration depth of the short needle tip is shallow, it is not easy to cause the needle to bend or break. With the rapid injection of the torrent, the needle stays in the body for a short time during injection, which can reduce the interference of the movement of the injection object on the injection.

[0033] The ejecting short needle high-speed injection device provided by the present utility model further includes the above-mentioned ejecting short needle assembly and has all the above beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only the embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0035] Figure 1 It is a schematic structural diagram of the ejecting short needle assembly of the present utility model;

[0036] Figure 2Schematic diagram of the assembly of the push rod and the power spring of the present utility model;

[0037] Figure 3 Schematic diagram of the structure of the high-speed injection device with an ejectable short needle of the present utility model;

[0038] Figure 4 Cross-sectional view of the high-speed injection device with an ejectable short needle of the present utility model.

[0039] Figures 1-4 Among them, the reference numerals include:

[0040] 101, trigger switch; 102, short needle fixing knob; 103, butterfly compression spring; 104, short needle tip; 105, ejection valve core; 106, ejection return spring; 107, medicine outlet return spring; 108, medicine outlet check valve core; 109, trigger return spring; 201, injection valve core; 202, injection cavity; 203, injection push rod; 3, inlet check valve assembly; 301, connecting piece; 302, inlet port return spring; 303, inlet port valve core; 304, inlet valve body; 401, front fixing plate; 402, front end fixing piece; 403, push rod guide sleeve; 404, push rod; 405, power spring; 406, pressure adjustment plate; 407, rear guide plate; 408, rear end fixing piece; 409, sleeve; 5, drive assembly; 501, rotating cam; 502, roller. Detailed implementation manners

[0041] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0042] The core of the present utility model is to provide an ejectable short needle assembly, which can reduce the probability of needle breakage and needle bending, reduce the accumulation of liquid medicine in the body, and improve the injection efficiency. Another core of the present utility model is to provide a high-speed injection device with an ejectable short needle including the above-mentioned ejectable short needle assembly, which has high injection efficiency and high liquid medicine utilization rate.

[0043] Please refer to Figure 1 , the present utility model provides an ejectable short needle assembly, including:

[0044] An injection cavity 202 for storing a medium, and the internal pressure of the injection cavity 202 is variable;

[0045] The ejection valve core 105 slidably installed in the injection cavity 202 in the form of a plunger, and the short needle tip 104 communicated with the high-pressure end face of the injection cavity 202 through the valve body;

[0046] When the pressure in the injection cavity 202 increases, the ejection valve core 105 can move in the first direction;

[0047] The valve body can only be in a connected state when the internal pressure in the injection cavity 202 exceeds the set threshold;

[0048] Or the valve body can only be in a connected state after the displacement of the ejection valve core 105 is greater than the set threshold.

[0049] When in use, the injection cavity 202 is filled with liquid medicine, and then by quickly increasing the internal pressure of the injection cavity 202, the ejection valve core 105 is pushed forward quickly, that is, ejection occurs, driving the short needle tip 104 to quickly puncture the injection position. When the injection needle tip 104 punctures to the set depth, that is, when the movement displacement of the ejection valve core 105 reaches the specified position, the valve body opens, and the liquid medicine in the injection cavity 202 is quickly discharged in the form of a torrent under the action of pressure through the short needle tip 104;

[0050] Or after the short needle tip 104 is ejected, during its ejection process, the pressure in the injection cavity 202 continues to increase until it exceeds the set threshold, then the valve body opens, and the liquid medicine is quickly discharged along the short needle tip 104 under the action of the internal pressure.

[0051] It should be noted that there is no limitation on the form of the valve body here. In some embodiments, the valve body adopts an electromagnetic valve, that is, the opening and closing of the valve body are controlled separately by other instructions, which mainly depends on the monitoring of the movement amount of the ejection valve core 105 and the short needle tip 104, or the monitoring of the pressure in the injection cavity 202. When either of them exceeds the set threshold, the valve body can be controlled to open to quickly discharge the liquid medicine.

[0052] In some embodiments, the valve body is a pressure relief valve, that is, when the pressure in the injection cavity 202 exceeds the set threshold, the valve body can automatically open to quickly discharge the liquid medicine, thus eliminating the use of many monitoring devices and helping to reduce the complexity of the device.

[0053] In some other embodiments, the valve body adopts a mechanical valve, that is, when the ejection valve core 105 moves to a specified position in the injection cavity 202, the valve stem in the valve body interacts with the protrusion or groove at this position in the injection cavity 202, making the valve body conduct, so that the liquid medicine can be quickly discharged through the valve body. When the ejection valve core 105 resets, the valve stem disengages from the protrusion or groove at this position, so that the valve body closes and cuts off the liquid medicine transmission channel.

[0054] Meanwhile, there is no restriction on the assembly method of the short needle tip 104 and the ejection valve core 105 here. In some embodiments, an integrated design of the short needle tip 104 and the ejection valve core 105 is adopted, which has strong integrity and reduces the assembly process. In some other embodiments, a split design is adopted, and the short needle tip 104 and the ejection valve core 105 are connected in the manner of a standard joint. A short needle fixing knob 102 connected to the ejection valve core 105 by a thread is provided to fix the short needle tip 104. A butterfly compression spring 103 is added inside the short needle fixing knob 102 to apply a compression pre-tightening force to the short needle tip 104, further ensuring that it will not fall off and ensuring the sealing performance at its joint. At the same time, adopting this split design of the short needle tip 104 and the ejection valve core 105 helps to replace the short needle tip 104 and enables other components of the short needle ejection assembly to be reused.

[0055] In addition, the pressure relief valve includes a medicine outlet channel passing through the ejection valve core 105 and communicating with the short needle tip 104, a medicine outlet one-way valve core 108 for truncating the medicine outlet channel, and a medicine outlet return spring 107 for restraining the movement and avoidance of the medicine outlet one-way valve core 108;

[0056] The combination of the medicine outlet one-way valve core 108 and the medicine outlet return spring 107 is used to achieve the effect of the pressure relief valve, which can prevent the backflow of the liquid medicine or subcutaneous blood through the short needle tip 104. That is, after the pressure in the injection cavity 202 drops suddenly and during the pressure recovery process, the pressure relief valve is in the closed state. That is, the medium required for the pressure recovery of the injection cavity 202 needs to enter from other positions, which can be utilized for the re-filling of the liquid medicine in the injection cavity 202.

[0057] In addition, the axis of the medicine outlet channel coincides with that of the short needle tip 104, and the medicine outlet return spring 107 can restrain the medicine outlet one-way valve core 108 from moving and avoiding along the first movement direction. Such an arrangement can effectively reduce the radial dimension of the ejection valve core 105, that is, reduce the radial dimension of the ejection needle assembly, and facilitate the control of the overall volume of the device.

[0058] In some embodiments, after the ejection of the ejection valve core 105 is completed, no reset is required, that is, the short needle ejection assembly is used once. In such embodiments, the injection cavity 202 mostly adopts an extrusion type medicine bag design. By extruding the medicine bag, the internal pressure increases suddenly, driving the ejection of the ejection valve core 105 and the jet discharge of the liquid medicine. In this case, the short needle tip 104 and the ejection valve core 105 do not need to be reset;

[0059] In this embodiment, it further includes an ejection return spring 106 for restraining the displacement of the ejection valve core 105 and enabling the ejection valve core 105 to return to the starting point of displacement. When ejection is completed, the ejection return spring 106 is compressed and stores energy. When the liquid medicine is discharged, the pressure in the injection cavity 202 drops suddenly, and the ejection return spring 106 releases its potential energy, driving the short needle tip 104 and the ejection valve core 105 to reset. During the actual injection process, this process is that the short needle tip 104 is pulled out from the injection position, that is, the whole injection process is that the short needle tip 104 quickly pierces the skin and enters the muscle layer, the liquid medicine is quickly released in a turbulent flow form, and after the release is completed, the short needle tip 104 quickly exits the skin and muscle layer. The short needle tip 104 stays under the skin at the injection position for a short time, will not be interfered with by the movement of the person being injected, avoids broken needles and bent needles, and also reduces the disturbance of the needle to the puncture position caused by the movement of the person being injected, which helps to reduce the surface wound.

[0060] In addition, the injection cavity 202 is communicated with a medicine inlet, and a medicine inlet one-way valve assembly 3 is arranged at the medicine inlet.

[0061] In use, in more cases, the injection cavity 202 will be reused, then it involves the problem of refilling the liquid medicine in the injection cavity 202. By arranging the medicine inlet one-way valve assembly 3 at the medicine inlet, it can be ensured that when the internal pressure of the injection cavity 202 increases, the medicine inlet is always in a closed state, and the liquid medicine will not be discharged from the medicine inlet. And when the injection is completed and the injection cavity 202 decreases, since the valve body at the medicine outlet is in a closed state, the medicine inlet one-way valve assembly 3 can be opened, that is, the refilling of the liquid medicine from the medicine inlet is completed.

[0062] The medicine inlet one-way valve assembly 3 includes a medicine inlet valve body 304 and a connecting member 301 connecting the medicine inlet valve body 304 and the medicine inlet. A medicine inlet valve core 303 is arranged in the medicine inlet valve body 304, and a medicine inlet return spring 302 for restraining the medicine inlet valve core 303 from avoiding and opening is provided.

[0063] In addition, in this embodiment, the injection cavity 202 adopts a straight cylinder design, that is, an injection valve core 201 is slidably arranged in the injection cavity 202 in the form of a plunger, and an injection push rod 203 for driving the injection valve core 201 to move forward or backward in the first movement direction;

[0064] During operation, the injection push rod 203 moves quickly in the first direction, pushing the injection valve core 201 to quickly compress the volume in the injection cavity 202, increasing the internal pressure. Under the action of the pressure, the ejection valve core 105 is pushed for ejection. Since the maximum stroke of the ejection valve core 105 is less than the maximum stroke of the injection valve core 201, the pressure in the injection cavity 202 continues to increase until it exceeds the set threshold of the pressure relief valve, that is, the outlet return spring 107 is compressed, and the outlet one-way valve core 108 moves backward to avoid, opening the medicine outlet channel, and the liquid medicine is quickly discharged through the short needle tip 104.

[0065] The injection push rod 203, the injection valve core 201, the medicine outlet channel, and the short needle tip are all coaxially arranged, which helps to reduce the resistance of the medicine liquid discharge, that is, increase the initial velocity of the jet when the medicine liquid is discharged, improve the diffusion ability of the medicine liquid in the muscle layer, and avoid the accumulation of the medicine liquid in the muscle layer.

[0066] Refer to Figures 2-4 , there is provided a high-speed injection device with an ejectable short needle, including the above-mentioned ejectable short needle assembly, and further including,

[0067] A push rod 404 that changes the pressure in the injection cavity 202 through its own movement;

[0068] A power spring 405 that makes the push rod 404 move rapidly along the first movement direction by releasing potential energy;

[0069] A driving assembly 5 that drives the push rod 404 to move in the reverse direction along the first movement direction and increases the internal elastic potential energy of the power spring 405.

[0070] It further includes a front fixing plate 401 and a sleeve 409 fixedly connected to the injection cavity 202. The push rod 404 and the power spring 405 are both installed in the sleeve 409. The two ends of the push rod 404 are respectively provided with a front end fixing part 402 and a rear end fixing part 408. The power spring 405 is coaxially arranged with the push rod 404 and is respectively fixed to the front end fixing part 402 and the pressure adjusting plate 406 at both ends. The pressure adjusting plate 406 and the end of the sleeve 409 can adjust the distance between the two through bolts, that is, adjust the initial compression amount of the power spring 405, that is, adjust the initial potential energy when the push rod 404 is released. At the same time, a push rod guide sleeve 403 and a rear guide plate 407 are respectively added at the front end of the push rod 404 and the end of the sleeve, both of which are used to improve the smoothness of the push rod 404 during the movement process and avoid the problem of jamming.

[0071] During operation, the push rod 404 moves quickly. It applies a force or a displacement to the injection cavity 202 through the movement to change the pressure in the injection cavity 202, complete the ejection of the short needle tip 104, and the jet injection of the medicine liquid. However, the action mode of the push rod 404 is not limited here. In some embodiments, the injection cavity 202 itself can reduce its internal volume through deformation, such as an elastic balloon. At this time, the push rod 404 can change its internal volume and increase the internal pressure by squeezing the injection cavity 202. In other embodiments, a plunger structure injection valve core 201 is adopted in the injection cavity 202, that is, the injection push rod 203 is connected through the push rod 404 to drive the injection valve core 201 to move, so as to change the internal volume of the injection cavity 202, change its internal pressure, and complete the ejection and jet injection.

[0072] The rapid movement of the push rod 404 mainly depends on the release of the potential energy of the power spring 405. Then, the driving assembly 5 is mainly used for the reverse movement of the push rod 404 and the energy storage of the power spring 405. The action mode of the driving assembly 5 is not limited here. It can be that the push rod 404 is manually pulled in the reverse direction of the first movement direction, driving the power spring 405 to be compressed for energy storage.

[0073] In some other embodiments, the driving assembly 5 includes a rotary cam 501 driven by a motor to rotate; a contact member in spiral slope contact with the rotary cam 501 and fixed to the end of the push rod 404; there is a vertical transition section between the low point and the high point of the spiral slope of the rotary cam 501.

[0074] The contact member includes a rear-end fixing member 408 fixedly arranged at the tail end of the push rod 404, and a roller 502 rotatably installed in the rear-end fixing member 408 and in rolling contact with the rotary cam 501. Refer to Figure 4 , the contact member is the rear-end fixing member 408 fixed to the tail end of the push rod 404, and the roller 502 is rotationally arranged in the rear-end fixing member 408 through a pin shaft.

[0075] That is, during operation, when the motor drives the rotary cam 501 to rotate one week, it drives the contact member to be lifted from the low point to the high point of the rotary cam and released at the high point. During the lifting process, that is, the push rod 404 moves in the reverse direction of the first movement direction, and the power spring 405 is compressed for energy storage. During the process of returning to the low point through the vertical transition section, that is, the power spring 405 releases potential energy, driving the push rod 404 to move rapidly in the first movement direction.

[0076] In addition, refer to Figure 4 , the ejector short needle assembly further includes a trigger switch 101 that can avoid moving in the reverse direction of the first movement direction to expose the short needle tip, and a trigger return spring 109 that inhibits the movement of the trigger switch 101 and can reset it; when the trigger switch 101 moves in the reverse direction of the first movement direction by more than a set threshold value, it can send an instruction to make the driving assembly 5 complete a single stroke cycle.

[0077] During operation, when in the non-injection state, the trigger switch 101 of the sleeve structure fully wraps the short needle tip 104, which helps to prevent the short needle tip 104 from being bent due to external force collision. When in the injection state, the trigger switch 101 first contacts the injection position and then retracts to avoid interference, sending an instruction to control the driving component 5 to perform a single-cycle operation. The process is that the motor drives the rotary cam 501 to rotate one week, driving the contact member to move from the low point to the high point of the rotary cam 501. During this process, through the transmission of the injection push rod 203 by the push rod 404, the injection valve core 201 is driven to move in the reverse direction along the first movement direction, and the inlet check valve assembly 3 at the medicine inlet is opened to complete the liquid medicine supplement. Subsequently, the contact member passes through the transition section of the rotary cam 501, that is, it is quickly released from the high point. Under the action of the power spring 405, the injection valve core 201 quickly moves along the first movement direction, driving the ejection valve core 105 to complete the ejection, and the jet of the liquid medicine in the short needle tip 104. After completion, the ejection return spring 106 drives the ejection valve core 105 to reset, that is, the short needle tip 104 is pulled out, and one injection is completed.

[0078] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0079] The above has introduced in detail a kind of ejection short needle assembly and an ejection short needle high-speed injection device provided by the present invention. Specific examples are used herein to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. An ejection short needle assembly, characterized in that: include: An injection cavity (202) for storing a medium, wherein the internal pressure of the injection cavity (202) is variable; An ejection valve core (105) slidably mounted in the injection cavity (202) in the form of a plunger, and a short needle head (104) connected to the high-pressure end face of the injection cavity (202) through a valve body; When the pressure in the injection cavity (202) increases, the ejection valve core (105) can move along a first movement direction; The valve body can be in a connected state only when the internal pressure of the injection cavity (202) exceeds a set threshold; Or the valve body can be in a connected state only after the displacement of the ejection valve core (105) is greater than a set threshold value.

2. The ejection short pin assembly according to claim 1, characterized in that: The valve body is a pressure relief valve.

3. The ejection short needle assembly according to claim 2, characterized in that: The pressure relief valve comprises: a drug outlet passage penetrating the ejection valve core (105) and communicating with the short needle (104), a drug outlet one-way valve core (108) for cutting off the drug outlet passage, and a drug outlet return spring (107) for inhibiting the drug outlet one-way valve core (108) from moving and evading.

4. The ejection short needle assembly according to claim 3, characterized in that: The axis of the drug outlet channel and the short needle head (104) overlap, and the drug outlet return spring (107) can inhibit the valve core (108) of the drug outlet one-way valve from moving in the first movement direction.

5. The ejection short needle assembly according to any one of claims 1 to 4, characterized in that: It also includes an ejection return spring (106) for suppressing the displacement of the ejection valve core (105) and enabling the ejection valve core (105) to return to the displacement starting point.

6. The ejection short pin assembly according to claim 5, characterized in that: The injection cavity (202) is connected to a drug inlet, and a drug inlet one-way valve assembly (3) is provided at the drug inlet.

7. The ejection short pin assembly according to claim 6, characterized in that: An injection valve core (201) is slidably arranged in the injection cavity (202) in the form of a plunger, and an injection push rod (203) drives the injection valve core (201) to move forward or backward along the first movement direction.

8. A high-speed ejection short needle injection device, characterized in that: The ejection short needle assembly comprises any one of claims 1 to 7, further comprising: A push rod (404) that changes the pressure in the injection cavity (202) by moving itself; a power spring (405) that releases potential energy to enable the push rod (404) to move rapidly along the first movement direction; A driving component (5) is used to drive the push rod (404) to move in the opposite direction along the first movement direction and to increase the elastic potential energy inside the power spring (405).

9. The ejection short needle high-speed injection device according to claim 8, characterized in that: The driving assembly (5) comprises a rotating cam (501) driven to rotate by a motor; A contact piece that contacts the spiral slope of the rotating cam (501) and is fixed to the end of the push rod (404); There is a vertical transition section between the low point and the high point of the spiral slope of the rotating cam (501).

10. The ejection short needle high-speed injection device according to claim 9, characterized in that: The contact member comprises a rear end fixing member (408) fixedly arranged at the rear end of the push rod (404), and a roller (502) rotatably installed in the rear end fixing member (408) and in rolling contact with the rotating cam (501).

11. The ejection short needle high-speed injection device according to any one of claims 8 to 10, characterized in that: The ejection short needle assembly also includes a trigger switch (101) capable of avoiding in the reverse direction along the first movement direction to leak out the short needle needle head (104), and a trigger return spring (109) capable of inhibiting the movement of the trigger switch (101) and returning it to its original position; When the reverse displacement of the trigger switch (101) along the first movement direction is greater than a set threshold, an instruction can be sent to enable the drive component (5) to complete a single stroke cycle.

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