Needle self-inspection pen type injector and working method thereof

Abstract

The invention belongs to the technical field of instruments for inputting a medium into a human body or inputting the medium onto the human body, and particularly relates to a needle head self-checking pen type injector and a working method thereof.The needle head self-checking pen type injector comprises a pen container, a needle head self-checking pen type injector body and a needle head self-checking pen type injector body, the pen container is internally provided with a mounting cavity, and the front end of the mounting cavity is provided with a needle head inserting opening; the cartridge case is arranged at the front end of the mounting chamber; the pair of linkage mechanisms is symmetrically arranged at the needle head inserting port, and each of the two linkage mechanisms comprises a triggering piece and a baffle; in the process of installing the syringe needle, the trigger piece is pushed to enable the baffle to open the needle inserting gap, then whether the inner syringe needle of the syringe needle is bent or not is detected through the needle inserting gap, and it is avoided that the damaged inner syringe needle is inserted into the medicine cylinder to affect liquid injection; in the process of disassembling the syringe needle, residual liquid on the inner syringe needle is scraped through the baffle, and in the reset moving process of the baffle, the residual liquid is sucked through negative pressure, so that the residual liquid is prevented from polluting the medicine cylinder.

Description

Technical Field

[0001] The present invention belongs to the technical field of devices for injecting media into or onto the human body, and specifically relates to a component for connecting a needle with a syringe or a needle seat, and more particularly to a needle self-checking pen-type syringe and a working method thereof. Background Art

[0002] A pen syringe is a commonly used medical device that can be filled with the required injection cartridge, then installed with an injection needle, and finally the drug solution can be injected by pressing or twisting.

[0003] In the related art, the injection needle is installed later, and its inner needle needs to be inserted into the cartridge. However, during transportation and handling, the inner needle may bend and deform, and needles in different bending shapes may cause different injection problems.

[0004] In one scenario, the needle bends but does not affect its insertion into the cartridge. At this time, the geometry of the needle's internal channel changes, causing the drug solution to encounter greater resistance when passing through the bend or damaged area, resulting in slower flow, uneven injection speed, and prolonged injection time, which affects injection accuracy.

[0005] In another scenario, the needle is severely bent and cannot be inserted into the cartridge normally. At this time, if it is forced into place, the sealing rubber diaphragm at the end of the cartridge may be damaged.

[0006] Therefore, how to solve the technical problem that the bent needle affects the injection of the liquid in the cartridge is urgently needed to be solved by those skilled in the art.

[0007] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the invention

[0008] The disclosed embodiments at least provide a needle self-checking pen-type injector and a working method thereof.

[0009] In the first aspect, the embodiments of the present disclosure provide a needle self-checking pen-type injector, which includes: a pen barrel, in which an installation chamber is provided, and a needle insertion port is provided at the front end of the installation chamber; a drug cartridge, which is arranged at the front end of the installation chamber; and a pair of linkage mechanisms, which are symmetrically arranged at the needle insertion port, and both of the linkage mechanisms include: a trigger member and a baffle; wherein in the process of screwing the injection needle onto the pen barrel, the injection needle pushes the corresponding trigger member backward, so that the two baffles move away from each other to open a needle insertion gap for inserting the inner needle; and in the process of unscrewing the injection needle from the pen barrel, the inner needle gradually withdraws from the needle insertion gap, and the residual liquid on the surface of the inner needle is scraped off through the needle insertion gap, and after the inner needle leaves the needle insertion gap, the corresponding baffle is pushed to move toward each other through the resetting movement of the trigger member to close the needle insertion gap.

[0010] In an optional embodiment, the trigger member includes: a pressure piece and a transmission rod; wherein a threaded section is provided at the front end of the pen barrel, and the pressure piece extends out of the pen barrel and is located on the rear side of the threaded section; the transmission rod is connected to the pressure piece and is abutted against the baffle through a first wedge-shaped guide portion; in the process of screwing the injection needle onto the pen barrel, the injection needle pushes the corresponding pressure piece backward, causing the two baffles to move away from each other to open the needle insertion gap; in the process of unscrewing the injection needle from the pen barrel, the two pressure pieces are reset and moved, causing the two baffles to move toward each other to close the needle insertion gap.

[0011] In an optional embodiment, the first end face of the baffle is connected to the inner wall of the installation chamber through a spring; the side wall of the baffle is provided with a second wedge-shaped guide portion adapted to the first wedge-shaped guide portion; in the process of screwing the injection needle onto the pen barrel, when the two baffles open the needle insertion gap, the corresponding baffle is separated from the corresponding transmission rod.

[0012] In an optional embodiment, a semicircular groove is formed on the side of the baffle plate facing the cartridge, and the semicircular groove is connected to the second end surface of the baffle plate; wherein when the residual liquid on the surface of the inner needle is scraped off by the needle insertion gap, the residual liquid flows into the corresponding semicircular groove.

[0013] In an optional embodiment, a flow channel is opened in the semicircular groove, one end of the flow channel is connected to the semicircular groove, and the other end is connected to the first end face of the baffle; after the inner needle leaves the pin gap, the negative pressure of the corresponding baffle is reset to absorb the residual liquid in the semicircular groove.

[0014] In an optional embodiment, a guide cylinder is provided on the inner wall of the installation chamber, and the first end face of the baffle extends into the guide cylinder and is connected to the bottom of the guide cylinder through the spring; after the inner needle leaves the pin insertion gap, the two baffles move toward each other to generate negative pressure in the corresponding guide cylinder to absorb the residual liquid in the semicircular groove.

[0015] In an optional embodiment, an adsorption sponge is arranged in the guide cylinder; wherein when the transmission rod is disengaged from the baffle, the second wedge-shaped guide portion abuts against the guide cylinder.

[0016] In an optional embodiment, the ratio of the width of the pin gap to the diameter of the inner needle head is between 1.1-1.2.

[0017] On the second aspect, the embodiments of the present disclosure also provide a working method of a needle self-checking pen-type injector, which includes: in the process of screwing the injection needle onto the pen barrel, the injection needle pushes the corresponding trigger member backward, so that the two baffles move away from each other to open the needle gap for inserting the inner needle; in the process of unscrewing the injection needle from the pen barrel, the two baffles scrape off the residual liquid on the surface of the inner needle, and after the inner needle leaves the needle gap, the trigger member drives the corresponding baffle to move toward each other to close the needle gap.

[0018] In an optional embodiment, the working method of the needle self-checking pen-type injector further includes: in the process of unscrewing the injection needle from the pen barrel, the scraped residual liquid is absorbed by negative pressure through the facing movement of the two baffles.

[0019] The beneficial effects of the present invention are as follows: during the process of installing the injection needle, the needle self-checking pen-type injector and its working method push the trigger member to open the needle insertion gap, and then detect whether the inner needle of the injection needle is bent through the needle insertion gap, thereby avoiding the damaged inner needle from being inserted into the cartridge and affecting the injection; during the process of removing the injection needle, the baffle is used to scrape off the residual liquid on the inner needle, and during the resetting movement of the baffle, the negative pressure absorbs the residual liquid, thereby preventing the residual liquid from contaminating the cartridge.

[0020] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, this article specifically cites preferred embodiments and provides detailed descriptions as follows in conjunction with the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1A schematic diagram of the structure of a needle self-checking pen-type injector provided in an embodiment of the present disclosure; Figure 2 A schematic diagram of the structure of an injection needle provided by an embodiment of the present disclosure when the needle is not in contact with the pen barrel; Figure 3 A schematic diagram of the structure of an injection needle and a pen barrel provided by an embodiment of the present disclosure when they are screwed together until the needle insertion gap is fully opened; Figure 4 A schematic diagram of the structure of an injection needle and a pen barrel provided by an embodiment of the present disclosure when they are screwed into a locked state; Figure 5 A schematic diagram of the structure of a trigger provided in an embodiment of the present disclosure; Figure 6 A schematic diagram of the structure of a guide cylinder provided in an embodiment of the present disclosure; Figure 7 A schematic diagram of the structure of a baffle provided in an embodiment of the present disclosure; Figure 8 A schematic diagram of the structure of an inner needle tip provided in an embodiment of the present disclosure when the inner needle tip is bent so that the front end exceeds the insertion pin gap; Fig. 9 A schematic diagram of the structure when the front end of an inner needle provided in an embodiment of the present disclosure is straight.

[0024] In the figure: Pen holder 1, mounting chamber 11, needle plug port 12, threaded section 13, guide tube 14, adsorption sponge 15; Cartridge 2; Linkage mechanism 3, trigger member 31, pressure plate 311, transmission rod 312, first wedge-shaped guide portion 313, baffle 32, first end surface 321, spring 322, second wedge-shaped guide portion 323, semicircular groove 324, second end surface 325, flow channel 326, pin gap 33; Injection needle 4, inner needle 41. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In addition, in the drawings, the thickness of the components may be exaggerated or reduced in order to effectively describe the technical content.

[0027] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0028] like Figures 1 to 4 As shown, at least one embodiment provides a needle self-checking pen-type injector, which includes: a pen barrel 1, in which a mounting chamber 11 is opened, and a needle plug-in port 12 is opened at the front end of the mounting chamber 11; a drug cartridge 2, which is arranged at the front end of the mounting chamber 11; and a pair of linkage mechanisms 3, which are symmetrically arranged at the needle plug-in port 12, and the two linkage mechanisms 3 both include: a trigger member 31 and a baffle 32.

[0029] like Figure 2 As shown, when the injection needle 4 is not installed, the trigger member 31 pushes the baffle 32, so that the two baffles 32 are in a closed state to prevent the outside from contaminating the cartridge 2 in the installation chamber 11; then, during the process of installing the injection needle 4, the injection needle 4 moves along the F1 direction until the injection needle 4 is installed. Figure 3 shown.

[0030] like Figure 3 As shown, at this time, the injection needle 4 pushes the corresponding trigger member 31 back a distance, so that the two baffles 32 move away from each other to form a needle insertion gap 33, the size of which is the required size. At this time, the trigger member 31 and the baffle 32 are about to be separated, and the inner needle 41 of the injection needle 4 is just close to the needle insertion gap 33; then the injection needle 4 moves along the F1 direction until it is as shown in FIG. Figure 4 shown.

[0031] Specifically, Figure 8 As shown, in one application scenario, the inner needle 41 of the inserted injection needle 4 is greatly bent and exceeds the needle insertion gap 33. At this time, the injection needle 4 will be blocked by the baffle 32 and cannot be inserted into the needle insertion gap 33, and the installation of the needle cannot be completed, thereby preventing the injection needle 4 with a large degree of bending from being inserted.

[0032] Specifically, Fig. 9 As shown, in another application scenario, the front end of the inner needle 41 of the inserted injection needle 4 is straight, but the rear section thereof is slightly bent. At this time, the inner needle 41 will be squeezed and straightened due to the existence of the needle insertion gap 33, thereby straightening and repairing the needle with a smaller degree of bending.

[0033] like Figure 4As shown, the injection needle 4 has been screwed to a locked state; Figure 3 to Figure 4 During the process of removing the injection needle 4, if the inner needle 41 is bent, it will be blocked by the baffle 32 and cannot be inserted into the needle insertion gap 33; Figure 4 Move in the F2 direction until Figure 3 shown.

[0034] like Figure 3 As shown, at this time, the injection needle 4 retreats to make the corresponding trigger member 31 move forward to just fit with the baffle 32; Figure 4 to Figure 3 During the process, the size of the needle gap 33 does not change, so that the residual liquid on the surface of the inner needle 41 is scraped off by the baffle 32; then the injection needle 4 Figure 3 Move in the direction of F2 until Figure 2 shown.

[0035] like Figure 2 As shown, the injection needle 4 is now disassembled; Figure 3 to Figure 2 During the process, when the inner needle 41 just leaves the pin insertion gap 33, the trigger member 31 fits against the baffle 32, and the reset movement of the trigger member 31 starts to push the baffle 32 to close, so as to prevent the cartridge 2 from being contaminated by the outside world.

[0036] In this embodiment, during the process of installing the injection needle 4, the trigger member 31 is pushed to open the needle insertion gap 33 so that the baffle 32 can open the needle insertion gap 33, and then the inner needle 41 of the injection needle 4 is detected to see if it is bent, so as to avoid the damaged inner needle 41 from being inserted into the cartridge 2 and affecting the injection; during the process of removing the injection needle 4, the residual liquid on the inner needle 41 is scraped off by the baffle 32, and during the resetting movement of the baffle 32, the negative pressure absorbs the residual liquid, thereby preventing the residual liquid from contaminating the cartridge 2.

[0037] like Figure 5 As shown, in some embodiments, the trigger member 31 includes: a pressure piece 311 and a transmission rod 312, the front end of the pen barrel 1 is provided with a threaded section 13, the pressure piece 311 extends out of the pen barrel 1 and is located on the rear side of the threaded section 13; wherein, the transmission rod 312 is connected to the pressure piece 311, and is abutted against the baffle 32 through the first wedge-shaped guide portion 313; in the process of screwing the injection needle 4 onto the pen barrel 1, the injection needle 4 pushes the corresponding pressure piece 311 backward, so that the two baffles 32 move away from each other to open the needle insertion gap 33; in the process of unscrewing the injection needle 4 from the pen barrel 1, the two pressure pieces 311 are reset and moved, so that the two baffles 32 move toward each other to close the needle insertion gap 33.

[0038] In this embodiment, the transmission rod 312 and the baffle plate 32 are transmitted via the first wedge-shaped guide portion 313 , and when the two are against each other, the baffle plate 32 is moved up and down by the lateral movement of the transmission rod 312 to open and close the pin gap 33 .

[0039] like Figure 6 As shown, in some embodiments, the first end surface 321 of the baffle 32 is connected to the inner wall of the installation chamber 11 through a spring 322 ; the side wall of the baffle 32 is provided with a second wedge-shaped guide portion 323 adapted to the first wedge-shaped guide portion 313 .

[0040] In this embodiment, when the injection needle 4 is screwed onto the pen barrel 1 , the transmission rod 312 moves along the direction of F3 , and at this time, the baffle 32 is pulled by the spring 322 to move downward to open the needle insertion gap 33 .

[0041] like Figure 7 As shown, in some embodiments, a semicircular groove 324 is formed on a side of the baffle plate 32 facing the cartridge 2 , and the semicircular groove 324 is connected to the second end surface 325 of the baffle plate 32 .

[0042] In this embodiment, when the pin gap 33 scrapes away the residual liquid on the surface of the inner needle head 41 , the residual liquid will flow into the corresponding semicircular groove 324 .

[0043] like Figure 7 As shown, in some embodiments, a flow channel 326 is defined in the semicircular groove 324 , one end of the flow channel 326 is communicated with the semicircular groove 324 , and the other end of the flow channel 326 is communicated with the first end surface 321 of the baffle 32 .

[0044] In this embodiment, after the inner needle 41 leaves the needle insertion gap 33 , the negative pressure due to the return movement of the corresponding baffle 32 absorbs the residual liquid in the semicircular groove 324 .

[0045] like Figure 7 As shown, in some embodiments, a guide cylinder 14 is disposed on the inner wall of the installation chamber 11 , and the first end surface 321 of the baffle 32 extends into the guide cylinder 14 and is connected to the bottom of the guide cylinder 14 through a spring 322 .

[0046] In this embodiment, after the inner needle head 41 leaves the pin insertion gap 33, the two baffles 32 move toward each other, so that the space between the first end surface 321 and the bottom of the guide tube 14 increases to generate negative pressure, thereby sucking the residual liquid in the semicircular groove 324 to the bottom of the guide tube 14 through the flow channel 326.

[0047] like Figure 7 As shown, in some embodiments, an adsorption sponge 15 is disposed in the guide cylinder 14 , and when the transmission rod 312 is disengaged from the baffle 32 , the second wedge-shaped guide portion 323 abuts against the guide cylinder 14 .

[0048] In this embodiment, the adsorption sponge 15 serves to prevent the residual from flowing back.

[0049] In some embodiments, the ratio of the width of the pin gap 33 to the diameter of the inner needle 41 is between 1.1 and 1.2.

[0050] At least one embodiment also provides a working method of a needle self-checking pen-type injector, which includes: in the process of screwing the injection needle 4 onto the pen barrel 1, the injection needle 4 pushes the corresponding trigger member 31 backward, so that the two baffles 32 move away from each other to open the needle insertion gap 33 for inserting the inner needle 41; in the process of unscrewing the injection needle 4 from the pen barrel 1, the two baffles 32 scrape off the residual liquid on the surface of the inner needle 41, and after the inner needle 41 leaves the needle insertion gap 33, the trigger member 31 drives the corresponding baffle 32 to move toward each other to close the needle insertion gap 33.

[0051] In some embodiments, the working method of the needle self-checking pen-type injector further includes: in the process of unscrewing the injection needle 4 from the pen barrel 1 , the scraped residual liquid is absorbed by the negative pressure through the facing movement of the two baffles 32 .

[0052] Regarding the specific structure and implementation process of the needle self-checking pen-type injector, please refer to the relevant discussion in the above embodiments, which will not be repeated here.

[0053] In summary, in the process of installing the injection needle 4, the present needle self-checking pen-type injector and its working method push the trigger member 31 to make the baffle 32 open the needle insertion gap 33, and then detect whether the inner needle 41 of the injection needle 4 is bent through the needle insertion gap 33, so as to avoid the damaged inner needle 41 from being inserted into the cartridge 2 and affecting the injection; in the process of removing the injection needle 4, the residual liquid on the inner needle 41 is scraped off by the baffle 32, and the negative pressure absorbs the residual liquid during the resetting movement of the baffle 32, thereby preventing the residual liquid from contaminating the cartridge 2.

[0054] Herein, when it is mentioned that a first component is located on a second component, this may mean that the first component may be directly formed on the second component, or a third component may be interposed between the first component and the second component.

[0055] In this article, when an element or layer is referred to as being "located on," "engaged to," "connected to," "attached to," or "coupled to" another element or layer, it may be directly located on, engaged, connected, attached to, or coupled to another element or layer, or there may be intermediate elements or layers. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," "directly attached to," or "directly coupled to" another element or layer, there may be no intermediate elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0056] Herein, example embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as "at least one of..." modify the entire list of elements when following a list of elements, rather than modifying individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0057] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limited. As used herein, the singular articles "one", "an" and "the" may also be intended to include plural forms, unless it is clearly indicated above that this is not the case. The terms "comprise", "include" and "have" are inclusive, and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the specific order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0058] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Therefore, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, so that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. On the contrary, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0059] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, terms such as "first", "second" and other numerical terms do not imply an order or sequence when used in this document unless explicitly indicated above. Therefore, without departing from the teachings of the example embodiments, the first element, component, region, layer or section discussed above may be referred to as a second element, component, region, layer or section.

[0061] Spatially relative terms, such as "inside", "outside", "below", "below", "down", "above", "on", etc., may be used herein to facilitate description of the relationship of one element or feature to another element or feature as illustrated in the figure. In addition to the orientation depicted in the figure, spatially relative terms may be intended to cover different orientations of the device in use or operation. For example, if the device in the figure is turned over, the elements described as "below" or "below" other elements or features will be oriented to be "above" other elements or features. Therefore, the example term "below" can cover the orientation above and below. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are interpreted accordingly.

[0062] In the above discussion, unless otherwise stated, the terms "about," "approximately," "substantially," etc., when used to describe a numerical value, mean a variation of + / - 10% of the value.

[0063] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A needle self-checking pen-type injector, characterized in that: include: A pen holder (1) having an installation chamber (11) formed therein, wherein a needle insertion port (12) is formed at the front end of the installation chamber (11); A cartridge (2) disposed at the front end of the mounting chamber (11); as well as A pair of linkage mechanisms (3) are symmetrically arranged at the needle insertion port (12), and both linkage mechanisms (3) comprise: a trigger member (31) and a baffle (32); wherein When the injection needle (4) is screwed onto the pen barrel (1), the injection needle (4) pushes the corresponding trigger member (31) backward, causing the two baffles (32) to move away from each other to open the needle insertion gap (33) for the inner needle (41) to be inserted; and During the process of unscrewing the injection needle (4) from the pen barrel (1), the inner needle (41) gradually withdraws from the needle insertion gap (33), and the residual liquid on the surface of the inner needle (41) is scraped off through the needle insertion gap (33); and after the inner needle (41) leaves the needle insertion gap (33), the corresponding baffle (32) is pushed to move toward each other through the reset movement of the trigger member (31) to close the needle insertion gap (33).

2. The needle self-checking pen-type injector according to claim 1, characterized in that: The triggering member (31) comprises: a pressure-bearing sheet (311) and a transmission rod (312); wherein The front end of the pen barrel (1) is provided with a threaded section (13), and the pressure-bearing sheet (311) extends out of the pen barrel (1) and is located at the rear side of the threaded section (13); The transmission rod (312) is connected to the pressure plate (311) and abuts against the baffle plate (32) via a first wedge-shaped guide portion (313); When the injection needle (4) is screwed onto the pen barrel (1), the injection needle (4) pushes the corresponding pressure-bearing sheet (311) backward, causing the two baffles (32) to move away from each other to open the needle insertion gap (33); When the injection needle (4) is screwed off the pen barrel (1), the two pressure-receiving sheets (311) are reset and moved, causing the two baffles (32) to move toward each other to close the needle insertion gap (33).

3. The needle self-checking pen-type injector according to claim 2, characterized in that: The first end surface (321) of the baffle (32) is connected to the inner wall of the installation chamber (11) via a spring (322); The side wall of the baffle (32) is provided with a second wedge-shaped guide portion (323) adapted to the first wedge-shaped guide portion (313); During the process of screwing the injection needle (4) onto the pen barrel (1), after the two baffles (32) open the needle insertion gap (33), the corresponding baffle (32) is separated from the corresponding transmission rod (312).

4. The needle self-checking pen-type injector according to claim 3, characterized in that: A semicircular groove (324) is formed on a side of the baffle (32) facing the cartridge (2), and the semicircular groove (324) is in communication with a second end surface (325) of the baffle (32); When the needle insertion gap (33) scrapes away residual liquid on the surface of the inner needle head (41), the residual liquid flows into the corresponding semicircular groove (324).

5. The needle self-checking pen-type injector according to claim 4, characterized in that: A flow channel (326) is provided in the semicircular groove (324); one end of the flow channel (326) is in communication with the semicircular groove (324), and the other end of the flow channel (326) is in communication with the first end surface (321) of the baffle (32); After the inner needle (41) leaves the needle insertion gap (33), the negative pressure due to the reset movement of the corresponding baffle (32) absorbs the residual liquid in the semicircular groove (324).

6. The needle self-checking pen-type injector according to claim 5, characterized in that: The inner wall of the installation chamber (11) is provided with a guide cylinder (14); the first end surface (321) of the baffle (32) extends into the guide cylinder (14) and is connected to the bottom of the guide cylinder (14) via the spring (322); After the inner needle (41) leaves the needle insertion gap (33), the two baffles (32) move toward each other, so that negative pressure is generated in the corresponding guide cylinder (14) to absorb the residual liquid in the semicircular groove (324).

7. The needle self-checking pen-type injector according to claim 6, characterized in that: An adsorption sponge (15) is arranged in the guide cylinder (14); When the transmission rod (312) is disengaged from the baffle plate (32), the second wedge-shaped guide portion (323) abuts against the guide cylinder (14).

8. The needle self-checking pen-type injector according to claim 7, characterized in that: The ratio of the width of the pin insertion gap (33) to the diameter of the inner needle head (41) is between 1.1 and 1.

2.

9. A method for operating the needle self-checking pen-type injector according to any one of claims 1 to 8, characterized in that: include: When the injection needle (4) is screwed onto the pen barrel (1), the injection needle (4) pushes the corresponding trigger member (31) backward, causing the two baffles (32) to move away from each other to open the needle insertion gap (33) for inserting the inner needle (41); When the injection needle (4) is unscrewed from the pen barrel (1), the residual liquid on the surface of the inner needle (41) is scraped off by the two baffles (32), and after the inner needle (41) leaves the needle insertion gap (33), the trigger member (31) drives the corresponding baffle (32) to move toward each other to close the needle insertion gap (33).

10. The operating method of the needle self-checking pen-type injector according to claim 9, characterized in that: Also includes: When the injection needle (4) is screwed off the pen barrel (1), the scraped residual liquid is sucked by negative pressure through the facing movement of the two baffles (32).

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