Injection pen

Abstract

The invention relates to an injection pen, which comprises an injection assembly, which comprises a syringe, a piston, a piston rod and a needle, the piston is installed in the syringe, and the needle is fixed at the near end of the syringe; a needle hiding sleeve; when the injection pen is in an initial state, the needle hiding sleeve is in an initial position, the needle head is hidden in the needle hiding sleeve, and a distance S1 is reserved between the piston and the piston rod; in the process that the needle hiding sleeve is driven by external force to move in the direction towards the far end of the injection pen, firstly, the needle head stretches out of the needle hiding sleeve and completes needle insertion, and then the needle hiding sleeve drives the injection cylinder, the piston and the needle head to move synchronously till the needle hiding sleeve moves to the injection triggering position. The needle hiding sleeve triggers the piston rod to move in the direction towards the near end of the injection pen and pushes the piston to move so as to trigger the injection assembly to conduct injection. According to the injection pen, the needle inserting depth can be kept unchanged after needle inserting is completed, the pain feeling is relieved, and the injection experience of a user is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of injection devices, and particularly to an injection pen. Background Art

[0002] An injection pen injects a liquid medicine into the human body by injection, which is convenient to carry and use. When in use, the proximal end of the injection pen is pressed on the skin surface, so that the needle penetrates into the skin to the target position, and then the liquid medicine is injected.

[0003] Due to the dimensional tolerances of each component and the fitting tolerances existing in the assembly process, there may be a large needle insertion depth error between different injection pens. In order to ensure the normal triggering of injection by the injection pen, the actual needle insertion depth of the injection pen is usually configured to be greater than the theoretical needle insertion depth. Moreover, there is also a certain needle insertion stroke during the injection triggering process. This design makes it necessary to continue pressing to the maximum needle insertion stroke after the injection pen triggers the injection, which is likely to cause pain. Summary of the Invention

[0004] Based on the above defects in the prior art, the purpose of the present invention is to provide an injection pen, in which the needle insertion depth can remain unchanged after the needle insertion is completed, the pain is reduced, and the injection experience of the user is improved.

[0005] To this end, the present invention provides the following technical solutions.

[0006] The present invention provides an injection pen, which comprises:

[0007] An injection assembly, which includes an injection barrel, a piston, a piston rod and a needle. The piston is installed in the injection barrel, and the needle is fixed to the proximal end of the injection barrel;

[0008] A retractable needle sleeve; when the injection pen is in the initial state, the retractable needle sleeve is in the initial position, the needle is hidden in the retractable needle sleeve, and there is a distance S1 between the piston and the piston rod;

[0009] Wherein, during the process of driving the retractable needle sleeve to move in the direction towards the distal end of the injection pen by an external force, first, the needle extends out of the retractable needle sleeve and completes the needle insertion. Then, the retractable needle sleeve drives the injection barrel, the piston and the needle to move synchronously until the retractable needle sleeve moves to the injection triggering position, and the retractable needle sleeve triggers the piston rod to move in the direction towards the proximal end of the injection pen and push the piston to move, so as to trigger the injection assembly to inject.

[0010] Optionally, when the retractable needle sleeve is in the initial position, the retractable needle sleeve is not linked with the injection barrel;

[0011] After the needle insertion is completed, the hidden needle sleeve continues to move in the direction towards the distal end under an external force to a linkage position, and the hidden needle sleeve is linked with the syringe barrel so that the hidden needle sleeve can drive the syringe barrel, the piston and the needle to move synchronously.

[0012] Optionally, the injection pen further includes an elastic protection element located on the distal side of the syringe barrel;

[0013] When the syringe barrel moves in the direction towards the distal end along with the hidden needle sleeve, the distal end of the syringe barrel is in soft contact with the elastic protection element.

[0014] Optionally, the injection pen further includes a limiting sleeve. When the injection pen is in the initial state or the needle insertion state, the limiting sleeve restricts the piston rod from moving in the direction towards the proximal end to prevent the injection assembly from injecting.

[0015] Optionally, the elastic protection element is annular, sleeved on the outer periphery of the piston rod, and located between the distal end of the syringe barrel and the proximal end of the limiting sleeve;

[0016] When the syringe barrel moves in the direction towards the distal end along with the hidden needle sleeve, the syringe barrel presses the elastic protection element against the proximal end of the limiting sleeve.

[0017] Optionally, the elastic protection element is a metal part, which includes an annular main body and elastic pieces; one end of each elastic piece is connected to the annular main body, and the other end is a free end and extends obliquely in the direction towards the syringe barrel.

[0018] Optionally, the number of the elastic pieces is at least two, and all the elastic pieces are distributed in a circumferential array around the circumference of the annular main body.

[0019] Optionally, the elastic force of the elastic protection element is 1N - 8N, and the elastic force of the elastic protection element is greater than the force required for the needle to penetrate the skin.

[0020] Optionally, after the needle insertion is completed, the distance that the syringe barrel moves synchronously with the hidden needle sleeve is S2, and S1 > S2.

[0021] Optionally, the hidden needle sleeve is provided with a first abutting portion, and the syringe barrel is provided with a second abutting portion;

[0022] After the needle insertion is completed, the hidden needle sleeve continues to move in the direction towards the distal end under an external force to a linkage position, and the first abutting portion abuts against the second abutting portion in the direction towards the distal end, so that the hidden needle sleeve is linked with the syringe barrel, and further enables the hidden needle sleeve to drive the syringe barrel, the piston and the needle to move synchronously.

[0023] Optionally, the hidden needle sleeve is at least partially sleeved on the outer periphery of the syringe barrel. The first abutting portion is a first convex structure protruding from the inner wall of the hidden needle sleeve, and the second abutting portion is a flanging structure provided on the syringe barrel.

[0024] Optionally, the hidden needle sleeve includes a connected sleeve portion and an extension arm for triggering the injection assembly to perform an injection. The extension arm is provided with a stepped structure. When the injection pen is in the initial state, the needle is hidden in the sleeve portion.

[0025] The second abutting portion is a flanging structure provided on the syringe barrel. At least a part of the projection of the stepped structure in the direction towards the distal end falls on the flanging structure to form the first abutting portion.

[0026] Optionally, the injection pen further includes a window element mounted on the outer periphery of the syringe barrel for observing the remaining amount of liquid in the syringe barrel or the position of the piston.

[0027] After the needle insertion is completed, the hidden needle sleeve continues to move in the direction towards the distal end under an external force to a linkage position, and the hidden needle sleeve, the window element, and the syringe barrel are linked in sequence so that the hidden needle sleeve can drive the window element, the syringe barrel, the piston, and the needle to move synchronously.

[0028] Optionally, the window element is provided with a claw, and the proximal end of the syringe barrel is provided with a shoulder.

[0029] The claw is clamped to the shoulder to limit the movement of the syringe barrel relative to the window element in the direction towards the proximal end.

[0030] Optionally, the window element is provided with an abutting boss, and the distal end of the syringe barrel is provided with a flanging structure.

[0031] The abutting boss abuts against the flanging structure in the direction towards the distal end to limit the movement of the syringe barrel relative to the window element in the direction towards the proximal end.

[0032] Optionally, the hidden needle sleeve is provided with a limiting hole, and the window element is provided with a protruding portion inserted into the limiting hole.

[0033] When the hidden needle sleeve moves to the linkage position, the hole wall of the limiting hole abuts against the protruding portion in the direction towards the distal end, so that the hidden needle sleeve is linked with the window element, and further enables the hidden needle sleeve to drive the window element to move synchronously.

[0034] Optionally, the hidden needle sleeve includes a connected sleeve portion and an extension arm for triggering the injection assembly to perform an injection, and the extension arm is provided with a step structure; when the injection pen is in the initial state, the needle is hidden in the sleeve portion;

[0035] The window element is provided with a third abutting portion, and at least a part of the projection of the step structure in the direction towards the distal end falls on the third abutting portion;

[0036] When the hidden needle sleeve moves to the linkage position, the step structure abuts against the third abutting portion in the direction towards the distal end, so that the hidden needle sleeve is linked with the window element, and further enables the hidden needle sleeve to drive the window element to move synchronously.

[0037] Optionally, the injection pen further includes:

[0038] A limiting sleeve that restricts the piston rod from moving in the direction towards the proximal end when the injection pen is in the initial state or the needle-insertion state, so as to prevent the injection assembly from performing an injection;

[0039] An unlocking sleeve that is pushed by the hidden needle sleeve to move in the direction towards the distal end, so that the unlocking sleeve drives the piston rod to move to disengage from the restriction of the limiting sleeve, thereby triggering the injection assembly to perform an injection.

[0040] Optionally, when the hidden needle sleeve is in the initial position, the hidden needle sleeve abuts against the unlocking sleeve in the direction towards the distal end; during the entire movement of the hidden needle sleeve in the direction towards the distal end, the hidden needle sleeve pushes the unlocking sleeve to move synchronously.

[0041] Optionally, the limiting sleeve includes a limiting hole and a guiding hole that communicate with each other, a second convex structure protrudes from the circumferential surface of the piston rod, and the unlocking sleeve is provided with an unlocking inclined surface;

[0042] When the hidden needle sleeve is in the initial position, the second convex structure is inserted into the limiting hole, and the limiting hole restricts the piston rod from moving in the direction towards the proximal end;

[0043] When the hidden needle sleeve pushes the unlocking sleeve to move in the direction towards the distal end until the unlocking inclined surface abuts against the second convex structure, the second convex structure can drive the piston rod to rotate under the push of the unlocking inclined surface until the second convex structure enters the guiding hole, so that the piston rod can move in the direction towards the proximal end.

[0044] Optionally, the injection pen further includes a first elastic member;

[0045] When the injection pen is in the initial state, the first elastic member is in a compressed state; when the piston rod is disengaged from the restriction of the restriction hole, under the rebound force of the first elastic member and the guidance of the guiding hole, the piston rod can move in the direction towards the proximal end.

[0046] Optionally, the restriction sleeve is sleeved on the outer periphery of the piston rod, the unlocking sleeve is sleeved on the outer periphery of the restriction sleeve, and the unlocking inclined surface is arranged on the inner wall of the unlocking sleeve;

[0047] When the hidden needle sleeve is in the initial position, the second protruding structure passes through the restriction hole and is partially located on the side of the unlocking inclined surface facing the distal end.

[0048] Optionally, the piston rod is provided with a hollow cavity, and the injection pen further includes a first elastic member;

[0049] One end of the first elastic member is inserted into the hollow cavity and abuts against the cavity wall of the hollow cavity, so as to provide power for the movement of the piston rod in the direction towards the proximal end.

[0050] Optionally, the injection pen further includes a cage, which includes a limiting post and a substrate connected to each other; the limiting post is inserted into the hollow cavity, the first elastic member is sleeved on the outer periphery of the limiting post, and the other end of the first elastic member abuts against the substrate.

[0051] Optionally, the cage further includes a first elastic arm, the first elastic arm is provided with a snap structure, the restriction sleeve is provided with a relief notch, the unlocking sleeve is provided with a second elastic arm, and the second elastic arm is provided with a third protruding structure;

[0052] When the injection pen is in the initial state, the first elastic arm is inserted between the inner wall of the restriction sleeve and the outer wall of the piston rod, the snap structure is buckled with the surface wall of the relief notch to prevent the cage from moving in the direction towards the distal end, and the third protruding structure extends into the relief notch and abuts against the snap structure to limit the unlocking sleeve from moving in the direction towards the distal end;

[0053] When the force applied by the hidden needle sleeve on the unlocking sleeve in the direction towards the distal end is greater than a preset value, the second elastic arm opens outwards, so that the third protruding structure disengages from the snap structure and the relief notch, and further enables the unlocking sleeve to move in the direction towards the distal end.

[0054] Optionally, the injection pen further includes a housing, which is used to form the outer contour structure of the injection pen;

[0055] When the injection pen is in an initial state, the piston rod pushes the first elastic arm outward, so that the buckle structure is buckled with the clearance notch;

[0056] When the injection pen completes the injection, the rod arm of the piston rod disengages from the first elastic arm, and the first elastic arm resets inward, so that the snap structure disengages from the yielding gap, and the retaining frame moves toward the distal end under the rebound force of the first elastic member and hits the inner wall of the shell, making a collision sound to prompt that the injection pen has completed the injection.

[0057] The present invention has the following technical effects:

[0058] The present invention provides an injection pen, which improves the structure of the injection pen. Between the step of completing the injection of an injection component and the step of triggering the injection component to perform an injection, the syringe barrel, the piston and the needle can move toward the distal end of the injection pen together with the hidden needle cover to ensure that the depth of the needle inserted into the skin can remain unchanged after the injection is completed, that is, the needle will not continue to be inserted during the process of triggering the injection, thereby reducing the pain and improving the user's injection experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 is a structural cross-sectional view of the injection pen of the present invention when it is in an initial state;

[0060] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0061] Figure 3 An exploded view of the structure of the injection pen of the present invention;

[0062] Figure 4 It is a schematic diagram of the three-dimensional structure of the elastic protective element of the present invention;

[0063] Figure 5 It is a schematic diagram of the assembly structure of the hidden needle cover and the injection barrel when the hidden needle cover is in the initial position in the first embodiment of the present invention;

[0064] Figure 6 It is a structural cross-sectional view of the hidden needle sleeve in the first embodiment of the present invention;

[0065] Figure 7 It is a schematic diagram of the assembly structure of the hidden needle cover and the injection barrel when the hidden needle cover is in the initial position in the second embodiment of the present invention;

[0066] Figure 8 It is a schematic diagram of the assembly structure of the hidden needle cover and the injection barrel when the hidden needle cover is in the initial position in the third embodiment of the present invention;

[0067] Figure 9Schematic diagram of the assembly structure of the window element and the syringe barrel in the third embodiment of the present invention;

[0068] Figure 10 Stereoscopic cross-sectional view of the injection pen of the present invention in the initial state;

[0069] Figure 11 is Figure 10 Enlarged view at B in

[0070] Figure 12 Partially enlarged cross-sectional view of the injection pen of the present invention in the initial state;

[0071] Figure 13 Stereoscopic structure diagram of the cage of the present invention;

[0072] Figure 14 Structural cross-sectional view of the unlocking sleeve of the present invention;

[0073] Figure 15 Stereoscopic cross-sectional view of the injection pen when the unlocking sleeve of the present invention moves to the unlocking slope in contact with the second convex structure;

[0074] Figure 16 is Figure 15 Enlarged view at C in

[0075] Figure 17 Stereoscopic cross-sectional view of the injection pen when the needle hiding sleeve of the present invention moves to the unlocking position Figure One ;

[0076] Figure 18 Stereoscopic cross-sectional view of the injection pen when the needle hiding sleeve of the present invention moves to the unlocking position Figure Two .

[0077] Explanation of reference numerals

[0078] 100, injection pen;

[0079] 1, injection assembly; 11, syringe barrel; 111, flanging structure; 112, shoulder; 12, piston; 13, piston rod; 131, second convex structure; 132, hollow cavity; 14, needle;

[0080] 2, needle hiding sleeve; 21, sleeve part; 22, extension arm; 221, first convex structure; 222, step structure; 223, limiting hole;

[0081] 3, elastic protection element; 31, annular body; 32, elastic piece;

[0082] 41, limiting sleeve; 411, limiting hole; 4111, first hole wall; 412, guiding hole; 413, relief notch;

[0083] 42. Unlocking sleeve; 421. Unlocking inclined surface; 422. Second elastic arm; 4221. Third convex structure; 42211. First abutting surface; 423. Abutting protrusion

[0084] 5. Window element; 51. Claw; 52. Abutting boss; 53. Protrusion; 54. Third abutting portion; 55. Window body; 56. Arc-shaped rib; 57. Groove

[0085] 61. First elastic member; 62. Second elastic member

[0086] 7. Cage; 71. Limit post; 72. Substrate; 73. First elastic arm; 731. Buckle structure; 7311. Buckling surface; 7312. Second abutting surface

[0087] 8. Outer shell; 81. End cap; 82. Hollow housing; 821. Through hole; 83. End cover

[0088] 9. Needle cap Detailed implementation manners

[0089] In order to make the technical solutions and beneficial effects of the present invention more obvious and understandable, the following will be described in detail by listing specific embodiments. Unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application belongs

[0090] In the description of the present invention, unless otherwise clearly defined, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of the simplified description of the present invention, rather than indicating that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, that is, it cannot be understood as a limitation to the present invention

[0091] In the present invention, the terms "first" and "second" are only used for the purpose of clear description, and cannot be understood as the relative importance of the indicated features or the quantity of the indicated technical features. Therefore, the features defined with "first" and "second" may clearly include at least one such feature. In the description of the present invention, "a plurality of" means at least two; "several" means at least one; unless otherwise clearly defined

[0092] In the present invention, unless otherwise clearly defined, terms such as "installed", "connected", "joined", "fixed", "set", etc. shall be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral molding; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can also be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0093] In the present invention, unless otherwise clearly defined, the first feature being "on", "above", "over", "upon", "under", "beneath", "below", or "underneath" the second feature can be that the first feature is in direct contact with the second feature, or the first feature and the second feature are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over", or "upon" the second feature can be that the first feature is directly above or obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than the horizontal height of the second feature. The first feature being "under", "beneath", or "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than the horizontal height of the second feature.

[0094] Both the "upper" and "lower" mentioned in the present invention are based on the markings in Figure 1 the [specific reference].

[0095] The following will specifically describe the injection pen of the present invention according to Figures 1 to 18 [specific reference].

[0096] In the present embodiment, as Figures 1 to 3 shown, the injection pen 100 includes an injection assembly 1 and a needle concealment sleeve 2. The injection assembly 1 includes an injection cylinder 11, a piston 12, a piston rod 13, and a needle 14. The piston 12 is installed in the injection cylinder 11, and the needle 14 is fixed to the proximal end of the injection cylinder 11. When the injection pen 100 is in the initial state, there is a spacing S1 between the piston 12 and the piston rod 13, and moreover, the needle concealment sleeve 2 is in the initial position, and the needle 14 is hidden in the needle concealment sleeve 2. In this way, the needle concealment sleeve 2 plays a protective role for the needle 14 and prevents accidental injury caused by the exposure of the needle 14.

[0097] When using the injection pen 100, first press the proximal end face of the injection pen 100 (such as the upper end face of the injection pen shown in Figure 1 ) against the skin surface, the proximal end face of the needle concealment sleeve 2 contacts the skin, and then press the injection pen 100 towards the skin. In this way, the skin exerts a force on the needle concealment sleeve 2 in the direction towards the distal end of the injection pen 100 (the direction of this force is as shown in Figure 1The downward direction shown), to drive the hidden needle sleeve 2 to move in the direction towards the distal end of the injection pen 100. During the movement of the hidden needle sleeve 2, first, since the hidden needle sleeve 2 moves relative to the needle 14, the needle 14 extends out of the hidden needle sleeve 2 and the needle insertion is completed. Then, the hidden needle sleeve 2 drives the syringe barrel 11, the piston 12 and the needle 14 to move synchronously until the hidden needle sleeve 2 moves to the trigger injection position, and the hidden needle sleeve 2 triggers the piston rod 13 to move in the direction towards the proximal end of the injection pen 100. In this way, the piston rod 12 pushes the piston 12 to move in the direction towards the proximal end to trigger the injection assembly 1 to inject. That is, when using the injection pen 100, the user only needs to press the proximal end of the injection pen 100 against the skin surface, and through the movement of the hidden needle sleeve 2 in the direction towards the distal end of the injection pen 100, the needle insertion and injection can be completed successively.

[0098] It should be understood that when the injection pen 100 is in the initial state, there is a gap S1 between the piston 12 and the piston rod 13 to ensure that the piston 12 does not contact the piston rod 13 before the hidden needle sleeve 2 moves to the trigger injection position, and to avoid the injection assembly 1 starting to inject before the hidden needle sleeve 2 moves to the trigger injection position.

[0099] By adopting the above technical solution, the present application improves the structure of the injection pen 100. Between the step of the injection assembly 1 completing the needle insertion and the step of triggering the injection assembly 1 to inject, the syringe barrel 11, the piston 12 and the needle 14 can move together with the hidden needle sleeve 2 in the direction towards the distal end of the injection pen 100 to ensure that the depth of the needle 14 inserted into the skin remains unchanged after the needle insertion is completed, that is, the needle 14 will not continue to insert during the triggering of the injection, thereby being able to reduce the pain and improve the user's injection experience.

[0100] It should be understood that the "proximal end" herein refers to the end of the injection pen 100 and each component of the injection pen 100 facing the skin when the injection pen 100 is in use. On the contrary, the "distal end" refers to the end of the injection pen 100 and each component of the injection pen 100 facing away from the skin when the injection pen 100 is in use. For example, when using the injection pen 100, the needle 14 is located at the proximal end of the syringe barrel 11.

[0101] In one embodiment, when the retractable needle sleeve 2 is in the initial position, the retractable needle sleeve 2 is not linked to the syringe barrel 11. That is, before the injection pen 100 finishes puncturing, when the retractable needle sleeve 2 moves, the syringe barrel 11 does not move. After the puncturing is completed, the retractable needle sleeve 2 continues to move in the distal direction under an external force to the linked position. When the needle protection sleeve 2 is in the linked position, the retractable needle sleeve 2 is linked to the syringe barrel 11. Since a linkage relationship is established between the two, the retractable needle sleeve 2 can drive the syringe barrel 11 to move synchronously. At the same time, the syringe barrel 11 can drive the piston 12 installed inside it and the needle 14 installed at its proximal end to move synchronously. In this way, the needle 14 and the retractable needle sleeve 2 move synchronously, and there is no relative movement between the two, thereby ensuring that the needle 14 does not continue to penetrate and the penetration depth remains unchanged. Moreover, during the processes of triggering injection, performing injection, and completing injection, the retractable needle sleeve 2 and the syringe barrel 11 remain linked. If the user slightly shakes the injection pen 100 back and forth, the penetration depth of the needle 14 will not change, further reducing the possible pain and further improving the user's injection experience.

[0102] In one embodiment, as Figure 2 shown, the injection pen 100 further includes an elastic protection element 3, and the elastic protection element 3 is located on the distal side of the syringe barrel 11. When the syringe barrel 11 moves in the distal direction along with the retractable needle sleeve 2, the distal end of the syringe barrel 11 is in soft contact with the elastic protection element 3. Specifically, the elastic protection element 3 has a certain elasticity and can undergo a certain deformation under the extrusion of the syringe barrel 11, thereby being able to reduce the acting force exerted by the elastic protection element 3 on the distal end of the syringe barrel 11. Therefore, the contact between the syringe barrel 11 and the elastic protection element 3 is relatively gentle and is not likely to cause damage to the syringe barrel 11, avoiding the direct hard contact between the distal end of the syringe barrel 11 and relatively hard components in the injection pen 100, and thus being able to prevent the syringe barrel 11 from being damaged and causing the injection pen 100 to be scrapped.

[0103] Furthermore, as Figure 1 and Figure 2 shown, the injection pen 100 further includes a limiting sleeve 41. When the injection pen 100 is in the initial state or the puncturing state, the limiting sleeve 41 can limit the movement of the piston rod 13 in the proximal direction to prevent the injection assembly 1 from injecting. When the retractable needle sleeve 2 moves to the injection-triggering position, the limiting sleeve 41 releases the restriction on the piston rod 13 to ensure that injection can only be performed after the puncturing is completed.

[0104] Furthermore, as Figures 1 to 4As shown, the elastic protection element 3 is annular, sleeved on the outer periphery of the piston rod 13, and located between the distal end of the syringe barrel 11 and the proximal end of the limiting sleeve 41. The syringe barrel 11 and the limiting sleeve 41 are sequentially distributed in the direction towards the distal end of the injection pen 100. When the syringe barrel 11 moves along with the needle shield 2 in the direction towards the distal end, the syringe barrel 11 presses the elastic protection element 3 against the proximal end of the limiting sleeve 41. In this solution, the elastic protection element 3 is an independent part, with fast assembly and no need for additional installation structures. Of course, the elastic protection element 3 can be integrated on the syringe barrel 11, or integrated on the limiting sleeve 41, or integrated on the housing 8 of the injection pen 100. In this way, the number of parts can be reduced and the assembly can be simplified.

[0105] Further, as Figure 2 shown, the distance between the syringe barrel 11 and the limiting sleeve 41 is 1 mm - 3 mm, preferably 1.5 mm, which is beneficial to quickly trigger the injection operation of the injection assembly 1.

[0106] In an embodiment, as Figure 2 and Figure 4 shown, the elastic protection element 3 is a metal part with high structural strength. The elastic protection element 3 includes an annular main body 31 and elastic pieces 32. One end of the elastic piece 32 is connected to the annular main body 31, and the other end of the elastic piece 32 is a free end and extends obliquely in the direction towards the syringe barrel 11. In this way, when the syringe barrel 11 moves in the direction towards the distal end of the injection pen 100, the distal end face of the syringe barrel 11 first contacts the free end of the elastic piece 32, and the elastic piece 32 is stressed and deformed to make way for the movement of the syringe barrel 11. The elastic protection element 3 in this solution has a simple structure and good elasticity. Of course, the material of the elastic protection element 3 is not limited to metal. For example, it can also be plastic.

[0107] Further, as Figure 4 shown, the number of the elastic pieces 32 is three. Of course, the number of the elastic pieces 32 is not limited to three, and can also be two, four or even more. Preferably, all the elastic pieces 32 are circumferentially arranged in a circular array around the annular main body 31, which is beneficial to the balanced force on the syringe barrel 11.

[0108] In one embodiment, the elastic force of the elastic protective element 3 is 1N-8N, preferably 2N-6N, and the elastic force of the elastic protective element 3 is greater than the force required for the needle 14 to penetrate the skin. Specifically, during the needle piercing process, the syringe 11 does not move synchronously with the hidden needle cover 2, and the needle 14 will be subjected to a reaction force during the process of penetrating the skin. This reaction force acts on the syringe 11 through the needle 14 in the direction toward the distal end of the syringe 11. Since the distal end of the syringe 11 is in soft contact with the elastic protective element 3, the abutment force of the elastic protective element 3 in the direction toward the proximal end of the syringe 11 needs to be greater than the force required for the needle 14 to penetrate the skin, so as to ensure that the needle 14 can penetrate the skin smoothly.

[0109] In one embodiment, after the needle is inserted, the distance that the syringe 11 moves synchronously with the hidden needle cover 2 is S2, S1>S2, and S2 can be 0.5mm-3mm. Specifically, after the needle is inserted, the syringe 11, the piston 12 and the needle 14 move synchronously with the hidden needle cover 2. When the hidden needle cover 2 moves to the trigger injection position, the piston rod 13 moves and pushes the piston 12 to move. This requires that before the hidden needle cover 2 moves to the trigger injection position, the synchronous movement of the piston 12 does not cause contact with the piston rod 13 and generate interaction force, but causes the piston 12 to move in the direction toward the proximal end of the injection pen 100, avoiding premature triggering of injection, and thus it is necessary to ensure that S1>S2.

[0110] In one embodiment, if Figure 1 and Figure 2 As shown, the injection pen 100 further includes an unlocking sleeve 42. When the hidden needle sleeve 2 moves in a direction toward the distal end of the injection pen 100, the hidden needle sleeve 2 pushes the unlocking sleeve 42 to move. During the movement, the unlocking sleeve 42 can drive the piston rod 13 to move, so that the piston rod 13 moves to escape the restriction of the restriction sleeve 41, thereby triggering the injection assembly 1 to perform injection. In this solution, the injection operation is triggered by the cooperation between the hidden needle sleeve 2 and the unlocking sleeve 42.

[0111] Furthermore, if Figure 2 As shown, when the hidden needle sleeve 2 is in the initial position, the hidden needle sleeve 2 abuts against the unlocking sleeve 42 in the direction toward the distal end. During the entire movement process of the hidden needle sleeve 2 in the direction toward the distal end, the hidden needle sleeve 2 pushes the unlocking sleeve 42 to move synchronously.

[0112] In one embodiment, if Figure 1 , Figure 2 , Figure 3 and Figure 5As shown, the hidden needle sleeve 2 includes a connected sleeve portion 21 and an extension arm 22. The sleeve portion 21 and the extension arm 22 are connected in sequence in the direction towards the distal end of the injection pen 100. The extension arm 22 is used to push the unlocking sleeve 42 to move so as to trigger the injection assembly 1 to perform an injection. Specifically, when the hidden needle sleeve 2 is in the initial position, the extension arm 22 abuts against the unlocking sleeve 42 in the direction towards the distal end. In this solution, the setting of the extension arm 22, on the one hand, is beneficial to reducing the weight of the injection pen 100, and on the other hand, the hidden needle sleeve 2 does not completely cover the syringe barrel 11, which is convenient for the user to observe the remaining liquid in the syringe barrel 11 or the real-time position of the piston 12 in the syringe barrel 11.

[0113] Further, as Figure 2 and Figure 5 shown, the number of the extension arms 22 is two, and the two extension arms 22 respectively abut against both sides of the proximal end face of the unlocking sleeve 42, which is beneficial to the balanced force on the unlocking sleeve 42. Of course, the number of the extension arms 22 can also be three, four or even more.

[0114] In an embodiment, as Figure 3 , Figure 10 , Figure 11 , Figures 14 to 16 shown, the limiting sleeve 41 includes a mutually communicating limiting hole 411 and a guiding hole 412. A second convex structure 131 is convexly provided on the circumferential surface of the piston rod 13. The unlocking sleeve 42 is provided with an unlocking inclined surface 421, and the unlocking inclined surface 421 inclines towards the guiding hole 412 in the direction towards the proximal end of the injection pen 100. As Figure 11 shown, when the hidden needle sleeve 2 is in the initial position, the second convex structure 131 is inserted into the limiting hole 411, and the first hole wall 4111 of the limiting hole 411 abuts against the second convex structure 131 in the direction towards the distal end of the injection pen 100. In this way, the limiting hole 411 can limit the movement of the piston rod 13 in the direction towards the proximal end of the injection pen 100. As Figure 16 shown, when the hidden needle sleeve 2 pushes the unlocking sleeve 42 to move in the direction towards the distal end until the unlocking inclined surface 421 abuts against the second convex structure 131, as Figure 17 and Figure 18 shown, under the push of the unlocking inclined surface 421, the second convex structure 131 can drive the piston rod 13 to rotate around its own central axis until the second convex structure 131 enters the guiding hole 412, and the piston rod 13 is released from the restriction of the limiting hole 411. In this way, the piston rod 13 can move in the direction towards the proximal end of the injection pen 100, and during the movement of the piston rod 13 in the direction towards the proximal end of the injection pen 100, the second convex structure 131 moves along the guiding hole 412, and the guiding hole 412 guides the moving direction of the piston rod 13 to prevent the piston rod 13 from rotating during the process of pushing the piston 12 to move.

[0115] It should be understood that the length of the guiding hole 412 in the linear movement direction of the piston rod 13 needs to be greater than or equal to the linear movement length of the piston rod 13 when the injection pen 100 completes injection, so as to avoid the guiding hole 412 interfering with the injection.

[0116] In one embodiment, as Figure 1 and Figure 2 shown, the injection pen 100 further includes a first elastic member 61. When the injection pen 100 is in the initial state, the first elastic member 61 is in a compressed state. When the piston rod 13 is released from the restriction of the restriction hole 411, under the rebounding force of the first elastic member 61 and the guidance of the guiding hole 412, the piston rod 13 can move in the direction towards the proximal end, that is, the first elastic member 61 provides injection power for the injection assembly 1 to achieve automatic injection. Preferably, the first elastic member 61 is a spring, which has a simple structure.

[0117] In one embodiment, as Figure 1 and Figure 11 shown, the restriction sleeve 41 is sleeved on the outer periphery of the piston rod 13, the unlocking sleeve 42 is sleeved on the outer periphery of the restriction sleeve 41, and the unlocking inclined surface 421 is provided on the inner wall of the unlocking sleeve 42. As Figure 1 and Figure 11 shown, when the needle shield 2 is in the initial position, the second convex structure 131 passes through the restriction hole 411 and is partially located on the side of the unlocking inclined surface 421 facing the distal end of the injection pen 100. Thus, when the unlocking sleeve 42 moves in the direction towards the distal end of the injection pen 100 under the push of the needle shield 2, as Figure 16 shown, the unlocking inclined surface 421 can move to contact the second convex structure 131, and during the continuous movement of the unlocking inclined surface 421, as Figure 17 shown, the unlocking inclined surface 421 can push the second convex structure 131 to rotate around the central axis of the plunger rod 11 until the second convex structure 131 enters the guiding hole 412.

[0118] Furthermore, as Figure 2 shown, the piston rod 13 is provided with a hollow cavity 132. One end of the first elastic member 61 is inserted into the hollow cavity 132 and abuts against the cavity wall of the hollow cavity 132. When the second convex structure 131 of the plunger rod 13 is released from the restriction of the restriction hole 411, the rebounding force of the first elastic member 61 acts on the cavity wall of the hollow cavity 132 to provide power for the movement of the piston rod 13 in the direction towards the proximal end of the injection pen 100.

[0119] Furthermore, as Figure 1 and Figure 2As shown, the injection pen 100 further includes a cage 7. The cage 7 includes a limiting post 71 and a substrate 72 connected to each other. The limiting post 71 is inserted into the hollow cavity 132. The first elastic member 61 is sleeved on the outer periphery of the limiting post 71, and the other end of the first elastic member 61 abuts against the substrate 72.

[0120] Further, as Figures 12 to 14 shown, the cage 7 further includes a first elastic arm 73. The first elastic arm 73 is provided with a snap structure 731. The limiting sleeve 41 is provided with a relief notch 413. The unlocking sleeve 42 is provided with a second elastic arm 422. The second elastic arm 422 is provided with a third protrusion structure 4221.

[0121] As Figure 1 and Figure 12 shown, when the injection pen 100 is in the initial state, the first elastic arm 73 is inserted between the inner wall of the limiting sleeve 41 and the outer wall of the piston rod 13, and the snap structure 731 is buckled with the surface wall of the relief notch 413. That is, the surface wall of the relief notch 413 abuts against the buckling surface 7311 of the snap structure 731 in the direction towards the proximal end of the injection pen 100. In this way, the surface wall of the relief notch 413 can prevent the cage 7 from moving in the direction towards the distal end of the injection pen 100. At the same time, the first elastic member 61 prevents the cage 7 from moving in the direction towards the proximal end of the injection pen 100, so that the cage 7 cannot move. In addition, as Figures 12 to 14 shown, the third protrusion structure 4221 extends into the relief notch 413, and the first abutting surface 42211 of the third protrusion structure 4221 abuts against the second abutting surface 7312 of the snap structure 731, thereby being able to restrict the unlocking sleeve 42 from moving in the direction towards the distal end of the injection pen 100 to ensure that the injection pen 100 will not be activated for injection when the injection pen 100 is in the unused state.

[0122] When the needleless sleeve 2 moves in the direction towards the distal end of the injection pen 100, the needleless sleeve 2 will apply a force to the unlocking sleeve 42. When this force is greater than a preset value (the resistance value caused by the second abutting surface 7312 of the snap structure 731 to the third protrusion structure 4221), the second elastic arm 422 expands outwards (not shown in the figure), so that the third protrusion structure 4221 disengages from the snap structure 731 and the relief notch 413. In this way, the unlocking sleeve 42 can smoothly move in the direction towards the distal end under the push of the needleless sleeve 2, and the restriction of the limiting sleeve 41 on the piston rod 13 is released through the movement of the unlocking sleeve 42, thereby smoothly triggering the injection.

[0123] Further, as Figures 12 to 14 shown, the first abutting surface 42211 and the second abutting surface 7312 are mating inclined surface structures, which is beneficial for the third protrusion structure 4221 to smoothly disengage from the restriction of the snap structure 731.

[0124] In the above scheme, when the injection pen 100 is in the initial state, the proximal end of the unlocking sleeve 42 is held by the hidden needle cover 2, and the unlocking sleeve 42 cannot move toward the proximal end of the injection pen 100. At the same time, the third protrusion structure 4221 of the unlocking sleeve 42 is held by the buckle structure 731 of the holder 7, and the unlocking sleeve 42 cannot move toward the distal end of the injection pen 100, thereby stably limiting the unlocking sleeve 42 to its initial position. In addition, as long as the force pressing on the hidden needle cover 2 reaches a certain value, the unlocking sleeve 42 can be released from the buckle structure 731 of the holder 7, and the injection operation can be triggered, which is easy to operate.

[0125] In one embodiment, Figure 1 and Figure 3 As shown, the injection pen 100 also includes a shell 8, which is used to constitute the outer contour structure of the injection pen 100, and the injection component 1, the hidden needle cover 2, the elastic protection element 3, the limiting sleeve 41, the unlocking sleeve 42, the first elastic member 61 and the retaining frame 7 are all located in the shell 8.

[0126] like Figure 12 and Figure 13 As shown, when the injection pen 100 is in the initial state, the piston rod 13 pushes the first elastic arm 73 outward, so that the buckle surface 7311 of the buckle structure 731 is buckled with the clearance notch 413. When the injection pen 100 completes the injection, the piston rod 13 moves to the proximal side of the retaining frame 7 (not shown in the figure) under the push of the first elastic member 61, and the rod arm of the piston rod 13 is separated from the first elastic arm 73, and the first elastic arm 73 is reset and deformed inward, so that the buckle structure 731 is separated from the clearance notch 413. In this way, the retaining frame 7 moves toward the distal end of the injection pen 100 under the rebound force of the first elastic member 61 and hits the inner wall of the housing 8, making a collision sound to prompt that the injection pen 100 has completed the injection.

[0127] In one embodiment, if Figure 13 As shown, the retainer 7 includes two first elastic arms 73. The retainer 7 has a symmetrical structure, and its longitudinal section is roughly in the shape of a "mountain".

[0128] In one embodiment, if Figure 1 and Figure 3 As shown, the housing 8 includes an end cap 81, a hollow shell 82 and an end cover 83 which are sequentially connected in a direction toward the distal end of the injection pen 100, so as to facilitate the assembly of the injection pen 100. When the injection is completed, the retainer 7 and the inner wall of the end cover 83 produce a collision sound to serve as a prompt.

[0129] In one embodiment, if Figure 1As shown, the distal end face of the limiting sleeve 41 abuts against the bottom wall of the end cap 83, and the proximal end face of the limiting sleeve 41 abuts against the silver needle sleeve 2, so that the limiting sleeve 41 cannot move in the outer shell 8.

[0130] In one embodiment, as Figure 1 and Figure 12 shown, the injection pen 100 further includes a second elastic member 62. The second elastic member 62 is sleeved on the outer periphery of the unlocking sleeve 42, and one end of the second elastic member 62 abuts against the abutting protrusion 423 of the unlocking sleeve 42, and the other end thereof abuts against the end cap 83. When the unlocking sleeve 42 moves in the direction of the distal end of the injection pen 100 under the push of the hidden needle sleeve 2, the second elastic member 62 is compressed; when the injection of the injection pen 100 is completed and the injection pen 100 is separated from the skin, the second elastic member 62 rebounds to drive the unlocking sleeve 42 to drive the hidden needle sleeve 2 to move in the direction of the proximal end of the injection pen 100 until the third protrusion structure 4221 of the unlocking sleeve 42 abuts against the buckle structure 731 of the cage 7 again, and both the hidden needle sleeve 2 and the unlocking sleeve 42 are reset, and the hidden needle sleeve 2 can hide the needle 14 again to avoid accidental injury to the user by the needle 14. Preferably, the second elastic member 62 is a spring, and the structure is simple.

[0131] In one embodiment, as Figure 1 and Figure 3 shown, the injection pen 100 further includes a needle sleeve 9. The needle sleeve 9 wraps the needle 14, and the part of the needle sleeve 9 in direct contact with the needle 14 has a certain flexibility to protect the needle 14. Further, the needle sleeve 9 is connected to the end cap 81. When using the injection pen 100, the needle sleeve 9 can be removed while removing the end cap 81, and then the proximal end face of the hidden needle sleeve 2 is pressed on the skin, and pressing can achieve needle insertion and injection, which is convenient to use.

[0132] In this solution, the linkage between the hidden needle sleeve 2 and the syringe barrel 11 can be that the hidden needle sleeve 2 is provided with a first abutting portion, and the syringe barrel 11 is provided with a second abutting portion. When the hidden needle sleeve 2 moves to the linkage position, the first abutting portion abuts against the second abutting portion in the direction of the distal end of the injection pen 100, so that the hidden needle sleeve 2 and the syringe barrel 11 are linked. It can also be that the hidden needle sleeve 2 in the linkage position is linked to the syringe barrel 11 by means of other parts. Regarding the specific linkage manner between the hidden needle sleeve 2 and the syringe barrel 11, three specific embodiments are introduced in detail in this application, as shown in the following First Embodiment, Second Embodiment and Third Embodiment. Of course, the linkage manner between the hidden needle sleeve 2 and the syringe barrel 11 is not limited to these three embodiments, as long as it satisfies that when the hidden needle sleeve 2 moves to the linkage position, the hidden needle sleeve 2 can drive the syringe barrel 11 to move synchronously.

[0133] First Embodiment

[0134] Next, according toFigures 5 to 6 Describe in detail the injection pen according to the first embodiment of the present invention.

[0135] In this embodiment, as Figure 5 and Figure 6 shown, the needle shield 2 is at least partially sleeved on the outer periphery of the syringe barrel 11. The first abutting portion is a first convex structure 221 convexly provided on the inner wall of the needle shield 2, and the second abutting portion is a flanging structure 111 provided on the syringe barrel 11. When the injection pen 100 finishes needle insertion and the needle shield 2 moves to the linkage position, the first convex structure 221 abuts against the flanging structure 111 (not shown in the figure) in the direction towards the distal end of the injection pen 100. Thus, when the needle shield 2 in the linkage position continues to move in the direction towards the distal end of the injection pen 100, the first convex structure 221 pushes the flanging structure 111, and then can drive the syringe barrel 11 and the piston 12 and the needle 14 installed on the syringe barrel 11 to move synchronously, that is, the needle shield 2, the syringe barrel 11, the piston 12 and the needle 14 move synchronously, and further the needle insertion depth is kept unchanged.

[0136] In this solution, the needle shield 2 in the linkage position is directly linked with the syringe barrel 11, and the linkage structure is simple and convenient for processing. Moreover, the original flanging structure 111 of the syringe barrel 11 is directly used for linkage with the needle shield 2 without changing the structure of the syringe barrel 11, which is beneficial to cost control.

[0137] In one embodiment, as Figure 5 shown, the needle shield 2 includes a connected sleeve portion 21 and an extension arm 22, and the first convex structure 221 is provided on the inner wall of the extension arm 22. Further, the number of the extension arms 22 is two, and it can be that some of the extension arms 22 are provided with the first convex structure 221, or it can be that all of the extension arms 22 are respectively provided with the first convex structure 221. Further, as Figure 6 shown, in order to facilitate the stable linkage between the needle shield 2 and the syringe barrel 11, at least two first convex structures 221 are provided on each extension arm 22.

[0138] Second embodiment

[0139] Next, according to Figure 7 Describe in detail the injection pen according to the second embodiment of the present invention.

[0140] In this embodiment, as Figure 7 shown, the needle shield 2 includes a connected sleeve portion 21 and an extension arm 22, and the extension arm 22 is provided with a step structure 222. As Figure 1 and Figure 2 shown, the extension arm 22 is used to push the unlocking sleeve 42 to move so as to trigger the injection assembly 1 to inject. As Figure 1As shown, when the injection pen 100 is in the initial state, the needle 14 is hidden in the sleeve portion 21. As Figure 7 shown, the second abutting portion is a flanging structure 111 provided on the syringe barrel 11; the stepped structure 222 at least partially falls on the flanging structure 111 in the projection along the direction towards the distal end to form the first abutting portion. In this way, when the needle- hiding sleeve 2 in the linkage position continues to move in the direction towards the distal end of the injection pen 100, the stepped structure 222 pushes the flanging structure 111, and thus can drive the syringe barrel 11 and the piston 12 and the needle 14 mounted on the syringe barrel 11 to move synchronously, that is, the needle- hiding sleeve 2, the syringe barrel 11, the piston 12 and the needle 14 move synchronously, so that the needle insertion depth remains unchanged.

[0141] In this solution, the needle- hiding sleeve 2 in the linkage position is directly linked with the syringe barrel 11, and the linkage structure is simple and convenient for processing. Moreover, the original flanging structure 111 of the syringe barrel 11 is directly used for linkage with the needle- hiding sleeve 2 without modifying the structure of the syringe barrel 11, which is beneficial to cost control.

[0142] In an embodiment, as Figure 7 shown, the number of the extension arms 22 is two, and it can be that the stepped structure 222 is provided on some of the extension arms 22, or it can be that the stepped structure 222 is provided on all of the extension arms 22 respectively.

[0143] The Third Embodiment

[0144] Next, according to Figures 8 to 9 the injection pen of the third embodiment of the present invention will be described in detail.

[0145] In this embodiment, as Figure 3 、 Figure 8 and Figure 9 shown, the injection pen 100 further includes a window element 5. The window element 5 is mounted on the outer periphery of the syringe barrel 11. The window element 5 is a transparent element or at least part of it is transparent. The hollow housing 82 of the injection pen 100 is provided with a through hole 821. Through the through hole 821 and the window element 5, the user can observe the remaining amount of the liquid in the syringe barrel 11 or observe the position of the piston 12. When the injection pen 100 finishes needle insertion, the needle- hiding sleeve 2 continues to move in the direction towards the distal end of the injection pen 100 under an external force to the linkage position. At this time, the needle- hiding sleeve 2, the window element 5 and the syringe barrel 11 are linked in sequence. In this way, when the needle- hiding sleeve 2 continues to move in the direction towards the distal end of the injection pen 100, the needle- hiding sleeve 2 can drive the window element 5 to move synchronously, and the window element 5 drives the syringe barrel 11 and the piston 12 and the needle 14 mounted on the syringe barrel 11 to move synchronously, that is, the needle- hiding sleeve 2, the window element 5, the syringe barrel 11, the piston 12 and the needle 14 move synchronously, so that the needle insertion depth remains unchanged.

[0146] In one embodiment, as Figure 9 shown, the window element 5 is provided with a clamping jaw 51, and the proximal end of the syringe barrel 11 is provided with a shoulder 112. The clamping jaw 51 is clamped to the shoulder 112 to limit the movement of the syringe barrel 11 relative to the window element 5 in the direction toward the proximal end of the injection pen 100. In this way, when the needle shield 2 drives the window element 5 to move in the direction toward the distal end of the injection pen 100, the window element 5 and the syringe barrel 11 are linked through the clamping connection between the clamping jaw 51 and the shoulder 112, so that the window element 5 can drive the syringe barrel 11 to move synchronously.

[0147] In one embodiment, as Figure 9 shown, the window element 5 is provided with an abutting boss 52, and the distal end of the syringe barrel 11 is provided with a flanging structure 111. The abutting boss 52 abuts against the flanging structure 111 in the direction toward the distal end of the injection pen 100 to limit the movement of the syringe barrel 11 relative to the window element 5 in the direction toward the proximal end of the injection pen 100. When the needle shield 2 drives the window element 5 to move in the direction toward the distal end of the injection pen 100, the window element 5 and the syringe barrel 11 are linked through the abutment between the abutting boss 52 and the flanging structure 111, so that the window element 5 can drive the syringe barrel 11 to move synchronously.

[0148] In a specific embodiment, as Figure 8 and Figure 9 shown, the linkage between the window element 5 and the syringe barrel 11 is carried out not only through the clamping connection between the clamping jaw 51 and the shoulder 112, but also through the abutment between the abutting boss 52 and the flanging structure 111 to improve the stability of the linkage between the two.

[0149] In one embodiment, as Figure 8 and Figure 9 shown, the needle shield 2 is provided with a limiting hole 223, the limiting hole 223 is in a long strip shape, and the window element 5 is provided with a protruding portion 53, and the protruding portion 53 is inserted into the limiting hole 223. When the silver needle shield 2 in the initial position moves to the linkage position, the limiting hole 223 moves relative to the protruding portion 53 until when the needle shield 2 moves to the linkage position, the hole wall of the limiting hole 223 abuts against the protruding portion 53 in the direction toward the distal end of the injection pen 100, so that the needle shield 2 and the window element 5 are linked. In this way, when the needle shield 2 continues to move to the trigger injection position, the limiting hole 223 can push the protruding portion 53 to move, and further the needle shield 2 can drive the window element 5 to move synchronously. Further, the limiting hole 223 can be a through hole or a blind hole.

[0150] Further, as Figure 8 shown, when the needle shield 2 is in the initial position, the protruding portion 53 abuts against one end hole wall at the distal end of the limiting hole 223, and when the needle shield 2 is in the linkage position, the protruding portion 53 abuts against one end hole wall at the proximal end of the limiting hole 223 (not shown in the figure).

[0151] In one embodiment, as Figure 8 shown, the needleless sleeve 2 includes a connected sleeve portion 21 and an extension arm 22. The extension arm 22 is used to trigger the injection assembly 1 to perform an injection. The extension arm 22 is provided with a step structure 222. When the injection pen 100 is in the initial state, the needle 14 is hidden in the sleeve portion 21. As Figure 8 and Figure 9 shown, the window element 5 is provided with a third abutting portion 54. At least a part of the projection of the step structure 222 in the direction toward the distal end falls on the third abutting portion 54. When the needleless sleeve 2 moves to the linkage position, the step structure 222 abuts against the third abutting portion 54 in the direction toward the distal end, so that the needleless sleeve 2 is linked with the window element 5, and further enables the needleless sleeve 2 to drive the window element 5 to move synchronously.

[0152] Furthermore, as Figure 3 and Figure 9 shown, the window element 5 is in a cylindrical shape and is sleeved on the outer periphery of the syringe barrel 11. The window element 5 includes a window body 55 and two arc-shaped ribs 56. The arc-shaped ribs 56 are connected to the distal end of the window body 55. The two arc-shaped ribs 56 are connected to the distal end of the window body 55 and form a groove 57. The abutting boss 52 of the window element 5 and the flanging structure 111 of the syringe barrel 11 are both located in the groove 57, and the abutting boss 52 abuts against the flanging structure 111. In addition, the end face of the proximal end of the arc-shaped rib 56 constitutes the third abutting portion 54. When the needleless sleeve 2 moves to the linkage position, the step structure 222 of the needleless sleeve 2 abuts against the end face of the proximal end of the arc-shaped rib 56.

[0153] In a specific embodiment, as Figure 8 and Figure 9 shown, the linkage between the needleless sleeve 2 and the window element 5 is carried out not only through the cooperation of the limiting hole 223 and the protruding portion 53, but also through the abutment of the step structure 222 and the third abutting portion 54 to improve the stability of the linkage between the two.

[0154] It should be understood that the above embodiments are all exemplary and do not cover all possible embodiments included in the claims. Without departing from the scope of the present disclosure, various deformations and changes can be made on the basis of the above embodiments. Similarly, various technical features of the above embodiments can be arbitrarily combined to form other embodiments of the present invention that may not be clearly described. Therefore, the above embodiments only represent several embodiments of the present invention and do not limit the protection scope of the present invention patent.

Claims

1. An injection pen, characterized in that: The injection pen (100) comprises: An injection assembly (1), comprising a syringe (11), a piston (12), a piston rod (13) and a needle (14), wherein the piston (12) is installed in the syringe (11), and the needle (14) is fixed to the proximal end of the syringe (11); A hidden needle cover (2); when the injection pen (100) is in an initial state, the hidden needle cover (2) is in an initial position, the needle (14) is hidden in the hidden needle cover (2), and a spacing S1 is left between the piston (12) and the piston rod (13); In the process of external force driving the hidden needle cover (2) to move in the direction toward the distal end of the injection pen (100), first, the needle (14) extends out of the hidden needle cover (2) and completes the needle insertion, and then, the hidden needle cover (2) drives the syringe barrel (11), the piston (12) and the needle (14) to move synchronously until the hidden needle cover (2) moves to the injection triggering position, and the hidden needle cover (2) triggers the piston rod (13) to move in the direction toward the proximal end of the injection pen (100) and pushes the piston (12) to move, so as to trigger the injection assembly (1) to perform injection.

2. The injection pen according to claim 1, characterized in that: When the hidden needle sleeve (2) is in the initial position, the hidden needle sleeve (2) and the injection cylinder (11) are not linked; After the needle insertion is completed, the hidden needle cover (2) continues to move in the direction toward the distal end to the linkage position under the external force, and the hidden needle cover (2) is linked with the syringe (11) so that the hidden needle cover (2) can drive the syringe (11), the piston (12) and the needle (14) to move synchronously.

3. The injection pen according to claim 1, characterized in that: The injection pen (100) further comprises an elastic protective element (3), which is located at a distal end side of the injection barrel (11); When the injection cylinder (11) moves along with the hidden needle sleeve (2) in the direction toward the distal end, the distal end of the injection cylinder (11) comes into soft contact with the elastic protective element (3).

4. The injection pen according to claim 3, characterized in that: The injection pen (100) further comprises a limiting sleeve (41), and when the injection pen (100) is in an initial state or an injection state, the limiting sleeve (41) limits the movement of the piston rod (13) in a direction toward the proximal end, so as to prevent the injection assembly (1) from performing an injection.

5. The injection pen according to claim 4, characterized in that: The elastic protective element (3) is annular and is sleeved on the outer circumference of the piston rod (13), and is located between the distal end of the injection cylinder (11) and the proximal end of the limiting sleeve (41); When the injection cylinder (11) moves along with the hidden needle sleeve (2) in the direction toward the distal end, the injection cylinder (11) presses the elastic protective element (3) onto the proximal end of the limiting sleeve (41).

6. The injection pen according to claim 3, characterized in that: The elastic protective element (3) is a metal part, comprising an annular body (31) and a spring sheet (32); one end of the spring sheet (32) is connected to the annular body (31), and the other end is a free end and extends obliquely in a direction toward the injection cylinder (11).

7. The injection pen according to claim 6, characterized in that: The number of the spring pieces (32) is at least two, and all the spring pieces (32) are distributed in a circular array around the circumference of the annular body (31); And / or, the elastic force of the elastic protective element (3) is 1N-8N, and the elastic force of the elastic protective element (3) is greater than the force required for the needle (14) to pierce the skin.

8. The injection pen according to any one of claims 1 to 7, characterized in that: After the acupuncture is completed, the distance that the syringe (11) moves synchronously with the hidden needle cover (2) is S2, and S1>S2.

9. The injection pen according to any one of claims 1 to 7, characterized in that: The hidden needle sleeve (2) is provided with a first abutment portion, and the injection cylinder (11) is provided with a second abutment portion; After the needle insertion is completed, the hidden needle cover (2) continues to move in the direction toward the distal end to the linkage position under the external force, and the first abutting portion abuts against the second abutting portion in the direction toward the distal end, so that the hidden needle cover (2) and the syringe (11) are linked, thereby enabling the hidden needle cover (2) to drive the syringe (11), the piston (12) and the needle (14) to move synchronously.

10. The injection pen according to claim 9, characterized in that: The hidden needle sleeve (2) is at least partially sleeved on the outer circumference of the injection barrel (11), the first abutting portion is a first protruding structure (221) protruding on the inner wall of the hidden needle sleeve (2), and the second abutting portion is a flange structure (111) provided on the injection barrel (11); Alternatively, the hidden needle cover (2) comprises a sleeve portion (21) and an extension arm (22) connected to each other, the extension arm (22) is used to trigger the injection assembly (1) to perform injection, and the extension arm (22) is provided with a step structure (222); when the injection pen (100) is in an initial state, the needle (14) is hidden in the sleeve portion (21); The second abutting portion is a flange structure (111) provided on the injection cylinder (11); the projection of the step structure (222) in the direction toward the distal end at least partially falls on the flange structure (111) to form the first abutting portion.

11. The injection pen according to any one of claims 1 to 7, characterized in that: The injection pen (100) further comprises a window element (5), which is mounted on the outer circumference of the injection barrel (11) and is used for observing the remaining amount of liquid in the injection barrel (11) or observing the position of the piston (12); After the needle insertion is completed, the hidden needle cover (2) continues to move in the direction toward the distal end to the linkage position under the external force, and the hidden needle cover (2), the window element (5) and the syringe (11) are linked in sequence, so that the hidden needle cover (2) can drive the window element (5), the syringe (11), the piston (12) and the needle (14) to move synchronously.

12. The injection pen according to claim 11, characterized in that: The window element (5) is provided with a claw (51), and the proximal end of the injection barrel (11) is provided with a shoulder (112); The claw (51) is engaged with the shoulder (112) to limit the movement of the syringe (11) relative to the window element (5) in the direction toward the proximal end; And / or, the window element (5) is provided with an abutment boss (52), and the distal end of the injection barrel (11) is provided with a flange structure (111); The abutting boss (52) abuts against the flange structure (111) in the direction toward the distal end, so as to limit the movement of the injection cylinder (11) relative to the window element (5) in the direction toward the proximal end; And / or, the hidden needle sleeve (2) is provided with a limiting hole (223), the window element (5) is provided with a protrusion (53), and the protrusion (53) is inserted into the limiting hole (223); When the hidden needle sleeve (2) moves to the linkage position, the hole wall of the limiting hole (223) abuts against the protruding portion (53) in the direction toward the distal end, so that the hidden needle sleeve (2) and the window element (5) are linked, and the hidden needle sleeve (2) can drive the window element (5) to move synchronously; And / or, the hidden needle cover (2) comprises a sleeve portion (21) and an extension arm (22) connected to each other, the extension arm (22) is used to trigger the injection assembly (1) to perform injection, and the extension arm (22) is provided with a step structure (222); when the injection pen (100) is in an initial state, the needle (14) is hidden in the sleeve portion (21); The window element (5) is provided with a third abutment portion (54), and the projection of the step structure (222) in the direction toward the distal end at least partially falls on the third abutment portion (54); When the hidden needle sleeve (2) moves to the linkage position, the step structure (222) abuts against the third abutment portion (54) in the direction toward the distal end, so that the hidden needle sleeve (2) and the window element (5) are linked, thereby enabling the hidden needle sleeve (2) to drive the window element (5) to move synchronously.

13. The injection pen according to any one of claims 1 to 7, characterized in that: The injection pen (100) further comprises: a limiting sleeve (41), which limits the piston rod (13) from moving in a direction toward the proximal end when the injection pen (100) is in an initial state or an injection state, so as to prevent the injection assembly (1) from performing an injection; The unlocking sleeve (42) is configured such that when the hidden needle sleeve (2) moves in the direction toward the distal end, the hidden needle sleeve (2) pushes the unlocking sleeve (42) to move, so that the unlocking sleeve (42) drives the piston rod (13) to move to escape from the restriction of the restriction sleeve (41), thereby triggering the injection assembly (1) to perform injection.

14. The injection pen according to claim 13, characterized in that: When the hidden needle sleeve (2) is in the initial position, the hidden needle sleeve (2) abuts against the unlocking sleeve (42) in the direction toward the distal end; during the entire movement process of the hidden needle sleeve (2) in the direction toward the distal end, the hidden needle sleeve (2) pushes the unlocking sleeve (42) to move synchronously.

15. The injection pen according to claim 14, characterized in that The limiting sleeve (41) comprises a limiting hole (411) and a guide hole (412) which are connected to each other, a second protruding structure (131) is convexly provided on the circumferential surface wall of the piston rod (13), and the unlocking sleeve (42) is provided with an unlocking inclined surface (421); When the hidden needle sleeve (2) is in the initial position, the second protruding structure (131) is inserted into the limiting hole (411), and the limiting hole (411) limits the movement of the piston rod (13) in the direction toward the proximal end; When the hidden needle sleeve (2) pushes the unlocking sleeve (42) to move in the direction toward the distal end until the unlocking inclined surface (421) abuts against the second protruding structure (131), the second protruding structure (131) can drive the piston rod (13) to rotate under the push of the unlocking inclined surface (421) until the second protruding structure (131) enters the guide hole (412), so that the piston rod (13) can move in the direction toward the proximal end.

16. The injection pen according to claim 15, characterized in that: The injection pen (100) further comprises a first elastic member (61); When the injection pen (100) is in an initial state, the first elastic member (61) is in a compressed state; when the piston rod (13) is free from the restriction of the restriction hole (411), under the guidance of the rebound force of the first elastic member (61) and the guide hole (412), the piston rod (13) can move in a direction toward the proximal end.

17. The injection pen according to claim 16, characterized in that The limiting sleeve (41) is sleeved on the outer circumference of the piston rod (13), the unlocking sleeve (42) is sleeved on the outer circumference of the limiting sleeve (41), and the unlocking inclined surface (421) is arranged on the inner wall of the unlocking sleeve (42); When the hidden needle sleeve (2) is in the initial position, the second protruding structure (131) passes through the limiting hole (411) and is partially located on a side of the unlocking slope (421) facing the distal end. Preferably, the piston rod (13) is provided with a hollow cavity (132), and the injection pen (100) further comprises a first elastic member (61); One end of the first elastic member (61) is inserted into the hollow cavity (132) and abuts against the cavity wall of the hollow cavity (132) to provide power for the piston rod (13) to move toward the proximal end. Preferably, the injection pen (100) further comprises a retaining frame (7), which comprises a connected limiting column (71) and a base plate (72); the limiting column (71) is inserted into the hollow cavity (132), the first elastic member (61) is sleeved on the outer periphery of the limiting column (71), and the other end of the first elastic member (61) abuts against the base plate (72). Preferably, the retaining frame (7) further comprises a first elastic arm (73), the first elastic arm (73) is provided with a buckle structure (731), the limiting sleeve (41) is provided with a clearance notch (413), the unlocking sleeve (42) is provided with a second elastic arm (422), and the second elastic arm (422) is provided with a third protruding structure (4221); When the injection pen (100) is in an initial state, the first elastic arm (73) is inserted between the inner wall of the limiting sleeve (41) and the outer wall of the piston rod (13), the buckle structure (731) is buckled with the surface wall of the clearance notch (413) to prevent the retaining frame (7) from moving in the direction toward the distal end, and the third protruding structure (4221) extends into the clearance notch (413) and abuts against the buckle structure (731) to limit the unlocking sleeve (42) from moving in the direction toward the distal end; When the force applied by the hidden needle sleeve (2) to the unlocking sleeve (42) in the direction toward the distal end is greater than a preset value, the second elastic arm (422) opens outward, so that the third protruding structure (4221) is disengaged from the buckle structure (731) and the clearance notch (413), thereby enabling the unlocking sleeve (42) to move in the direction toward the distal end. Preferably, the injection pen (100) further comprises a housing (8) for forming an outer contour structure of the injection pen (100); When the injection pen (100) is in an initial state, the piston rod (13) pushes the first elastic arm (73) outward, so that the buckle structure (731) is buckled with the clearance notch (413); When the injection pen (100) completes the injection, the rod arm of the piston rod (13) disengages from the first elastic arm (73), and the first elastic arm (73) resets inward, so that the buckle structure (731) disengages from the clearance notch (413), and the retaining frame (7) moves toward the distal end under the rebound force of the first elastic member (61) and hits the inner wall of the housing (8), emitting a collision sound, to prompt that the injection pen (100) has completed the injection.

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