Needle self-checking pen-type injector and its working method

Abstract

The present invention belongs to the technical field of devices for injecting a medium into or onto the human body, and specifically relates to a needle self-checking pen-type injector and a working method thereof. The needle self-checking pen-type injector comprises: a pen barrel, in which an installation chamber is provided, and a needle insertion interface 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 interface, and both linkage mechanisms comprise: a trigger member and a baffle; during the process of installing the injection needle, the needle self-checking pen-type injector pushes the trigger member to open the needle insertion gap, and then detects whether the inner needle of the injection needle is bent through the needle insertion gap, thereby preventing the damaged inner needle from being inserted into the drug cartridge and affecting the injection; during the process of removing the injection needle, the baffle scrapes off the residual liquid on the inner needle, and during the resetting movement of the baffle, negative pressure absorbs the residual liquid, thereby preventing the residual liquid from contaminating the drug cartridge.

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 connecting a needle and 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 will 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 liquid medicine to encounter greater resistance when passing through the bend or damaged area, resulting in slower flow, uneven injection speed, and prolonged injection time, thus affecting 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 insertion, 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 embodiments of the present disclosure at least provide a needle self-checking pen-type injector and a working method thereof.

[0009] In the first aspect, an embodiment of the present disclosure provides a needle self-checking pen-type injector, which includes: a pen barrel, in which a mounting chamber is provided, and a needle insertion port is provided at the front end of the mounting chamber; a drug cartridge, arranged at the front end of the mounting chamber; and a pair of linkage mechanisms, symmetrically arranged at the needle insertion port, and both 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, causing the two baffles to 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, scrapes off the residual liquid on the surface of the inner needle 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 the front end portion of the pen barrel is provided with a threaded section, 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 pin 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 facing the cartridge, and the semicircular groove is connected to the second end face of the baffle; wherein when the residual liquid on the surface of the inner needle is scraped off in the needle 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 and moved 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, so that negative pressure is generated in the corresponding guide cylinder to absorb the residual liquid in the semicircular groove.

[0015] In an optional embodiment, an adsorption sponge is provided 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 and 1.2.

[0017] On the second aspect, the embodiment of the present disclosure also provides 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, causing the two baffles to 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 are used to 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 operating 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 sucked 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 preventing 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 in part will 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, preferred embodiments are specifically cited herein and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0023] Figure 1A schematic structural diagram of a needle self-checking pen-type injector provided in an embodiment of the present disclosure;

[0024] 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;

[0025] Figure 3 This is 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;

[0026] 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;

[0027] Figure 5 A schematic structural diagram of a trigger provided in an embodiment of the present disclosure;

[0028] Figure 6 A schematic structural diagram of a guide cylinder provided in an embodiment of the present disclosure;

[0029] Figure 7 A schematic structural diagram of a baffle provided in an embodiment of the present disclosure;

[0030] Figure 8 A schematic diagram of the structure of an inner needle provided by an embodiment of the present disclosure when the inner needle is bent so that the front end exceeds the pin gap;

[0031] Figure 9 A schematic structural diagram of an embodiment of the present disclosure in which the front end of an inner needle is straight.

[0032] In the picture:

[0033] Pen holder 1, mounting chamber 11, needle plug port 12, threaded section 13, guide cylinder 14, adsorption sponge 15;

[0034] Cartridge 2;

[0035] 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;

[0036] Injection needle 4, inner needle 41. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0038] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. In addition, in the drawings, the thickness of components may be exaggerated or reduced in order to effectively describe the technical content.

[0039] The following embodiments of the present invention are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0040] 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 defined, and a needle insertion port 12 is defined 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 insertion port 12, and both linkage mechanisms 3 include: a trigger member 31 and a baffle 32.

[0041] like Figure 2 As shown, when the injection needle 4 is not installed, the trigger 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 it is as shown in FIG. Figure 3 shown.

[0042] 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 the needle insertion gap 33 is the required size. At this time, the trigger member 31 and the baffle 32 are in a state of being about to separate, and the inner needle head 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.

[0043] Specifically, such as Figure 8 As shown, in one application scenario, the inner needle 41 of the inserted injection needle 4 is greatly bent and has exceeded 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 needle installation cannot be completed, thereby preventing the injection needle 4 with a large degree of bending from being inserted.

[0044] Specifically, such as Figure 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.

[0045] like Figure 4 As shown, the injection needle 4 has been screwed to the locked state; Figures 3 and 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 gap 33; Figure 4 Move in the F2 direction until Figure 3 shown.

[0046] like Figure 3 As shown, at this time, the injection needle 4 retreats so that the corresponding trigger member 31 moves 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 F2 direction until Figure 2 shown.

[0047] 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 to prevent the cartridge 2 from being contaminated by the outside world.

[0048] In this embodiment, during the installation of 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. Subsequently, the inner needle 41 of the injection needle 4 is detected to see if it is bent, thereby preventing the damaged inner needle 41 from being inserted into the cartridge 2 and affecting the injection. During the removal of the injection needle 4, the baffle 32 is used to scrape off the residual liquid on the inner needle 41, and during the reset movement of the baffle 32, the negative pressure absorbs the residual liquid, thereby preventing the residual liquid from contaminating the cartridge 2.

[0049] like Figure 5As 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; when the pen barrel 1 is screwed onto the injection needle 4, the injection needle 4 pushes the corresponding pressure piece 311 backward, causing the two baffles 32 to move away from each other to open the needle insertion gap 33; when the pen barrel 1 is screwed off the injection needle 4, the two pressure pieces 311 are reset and moved, causing the two baffles 32 to move toward each other to close the needle insertion gap 33.

[0050] In this embodiment, the transmission rod 312 and the baffle 32 are transmitted via the first wedge-shaped guide portion 313. When the two are against each other, the baffle 32 is moved up and down by the lateral movement of the transmission rod 312 to open and close the pin gap 33.

[0051] 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 .

[0052] In this embodiment, when the injection needle 4 is screwed onto the pen barrel 1 , the transmission rod 312 moves in the direction of F3 , and the baffle 32 is pulled by the spring 322 to move downward to open the needle insertion gap 33 .

[0053] like Figure 7 As shown, in some embodiments, a semicircular groove 324 is formed on a side of the baffle 32 facing the cartridge 2 , and the semicircular groove 324 is communicated with the second end surface 325 of the baffle 32 .

[0054] In this embodiment, when the pin insertion 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 .

[0055] 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 is communicated with the first end surface 321 of the baffle 32 .

[0056] In this embodiment, after the inner needle 41 leaves the pin 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 .

[0057] like Figure 7 As shown, in some embodiments, a guide cylinder 14 is provided 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 via a spring 322 .

[0058] 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 under negative pressure.

[0059] like Figure 7 As shown, in some embodiments, an adsorption sponge 15 is provided 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 .

[0060] In this embodiment, the adsorption sponge 15 serves to prevent residual backflow.

[0061] 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.

[0062] At least one embodiment further provides a method for operating a needle self-checking pen-type injector, comprising: 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, causing the two baffles 32 to move away from each other to open a 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.

[0063] In some embodiments, the working method of the needle self-checking pen-type injector further includes: when the injection needle 4 is unscrewed from the pen barrel 1 , the scraped residual liquid is sucked by negative pressure through the facing movement of the two baffles 32 .

[0064] 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 and will not be repeated here.

[0065] 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 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 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.

[0066] 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.

[0067] As used herein, 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 the other element or layer, or there may be intervening elements or layers. Conversely, 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 intervening 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.

[0068] 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..." when following a list of elements modify the entire 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.

[0069] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limiting. As used herein, the singular articles "a", "an" and "the" may also be intended to include plural forms, unless otherwise clearly indicated herein. 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 particular order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0070] 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. Thus, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, such 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 advantageous over other implementations, aspects, or designs. Instead, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0071] In the description of the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0072] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are 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 limiting the present invention. In addition, terms such as "first", "second" and other numerical terms do not imply an order or sequence when used herein unless expressly 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.

[0073] Spatially relative terms, such as "inside," "outside," "below," "beneath," "down," "above," "on," etc., may be used herein to describe the relationship of one element or feature to another element or feature as illustrated in the figures. In addition to the orientations depicted in the figures, spatially relative terms may be intended to encompass different orientations of the device in use or operation. For example, if the device in the figures is flipped, an element described as being "below" or "below" other elements or features will be oriented to be "above" the other elements or features. Thus, the example term "below" may encompass both above and below orientations. The device may be oriented otherwise (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are interpreted accordingly.

[0074] In the above discussion, unless otherwise indicated, the terms "about," "approximately," "substantially," etc., when used to describe a numerical value, mean a variation of + / - 10% of the value.

[0075] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and 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) is provided with an installation chamber (11) therein, and a needle insertion port (12) is provided at the front end of the installation chamber (11); A cartridge (2) is arranged 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) include: a trigger member (31) and a baffle (32); wherein During the process of screwing the injection needle (4) onto the pen barrel (1), the injection needle (4) pushes the corresponding trigger (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), and then detecting whether the inner needle (41) of the injection needle (4) is bent through the needle insertion gap (33), thereby preventing the damaged inner needle (41) from being inserted into the cartridge (2) and affecting the injection; 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), scrapes off the residual liquid on the surface of the inner needle (41) through the needle insertion gap (33), and after the inner needle (41) leaves the needle insertion gap (33), the trigger (31) resets and pushes the corresponding baffle (32) to move toward each other to close the needle insertion gap (33); The triggering member (31) comprises: a pressure-bearing plate (311) and a transmission rod (312); wherein A threaded section (13) is provided at the front end of the pen barrel (1), and the pressure-bearing piece (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 (32) via a first wedge-shaped guide portion (313); During the process of screwing the injection needle (4) onto the pen barrel (1), the injection needle (4) pushes the corresponding pressure plate (311) back, causing the two baffles (32) to move away from each other to open the needle insertion gap (33); When the injection needle (4) is unscrewed from the pen barrel (1), the two pressure-receiving plates (311) are reset and moved, causing the two baffles (32) to move toward each other to close the needle insertion gap (33); 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).

2. The needle self-checking pen-type injector according to claim 1, characterized in that: A semicircular groove (324) is formed on one side of the baffle (32) facing the cartridge (2), and the semicircular groove (324) is in communication with the second end surface (325) of the baffle (32); When the pin 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).

3. The needle self-checking pen-type injector according to claim 2, 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 is in communication with the first end surface (321) of the baffle (32); After the inner needle (41) leaves the pin insertion gap (33), the negative pressure caused by the reset movement of the corresponding baffle (32) absorbs the residual liquid in the semicircular groove (324).

4. The needle self-checking pen-type injector according to claim 3, characterized in that: A guide cylinder (14) is provided on the inner wall of the installation chamber (11); a 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 pin 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).

5. The needle self-checking pen-type injector according to claim 4, characterized in that: An adsorption sponge (15) is provided in the guide cylinder (14); wherein When the transmission rod (312) is disengaged from the baffle (32), the second wedge-shaped guide portion (323) abuts against the guide cylinder (14).

6. The needle self-checking pen-type injector according to claim 5, 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.

7. A method for operating the needle self-checking pen-type injector according to any one of claims 1 to 6, characterized in that: include: During the process of screwing the injection needle (4) 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); During the process of unscrewing the injection needle (4) 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).

8. The operating method of the needle self-checking pen-type injector according to claim 7, characterized in that: Also includes: During the process of unscrewing the injection needle (4) from 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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