Autoinjector Pen

Abstract

The present invention relates to an automatic injection pen, comprising a shell, a hidden needle cover, an inner cover, and a syringe assembly; the pen cap structure is improved; the excitation mechanism is improved, and a locking mechanism in an unused state is added; the piston rod of the piston assembly is improved, and an elastic protrusion structure is added; a linear buffer is provided between the push head of the piston assembly and the piston in the syringe to delay the occurrence of the needle retracting action; a trigger claw excitation inner support is provided in the trigger claw passing window to provide support for the excitation process of the trigger claw; the connection structure between the hidden needle cover and the lower spring cover is improved. The automatic injection pen of the present invention has a more reliable structure, more thorough use of medicines, and can better meet the storage, transportation and use requirements of medicines in disposable syringes.

Description

Technical Field

[0001] The invention relates to an automatic injection pen and belongs to the field of medical injection equipment. Background Art

[0002] The applicant previously applied for and disclosed an automatic injection pen with Chinese patent publication number CN113499513A. The automatic injection pen adopts an automatic injection device and a spring linkage to achieve a one-time downward operation of holding the pen tube body to complete a full set of needle insertion, injection, and needle retraction actions, that is, the disposable syringe contained therein is pushed out, the medicine is pushed out, and the needle is pulled out and hidden, which reduces the operator's operating actions and achieves reliable drug injection.

[0003] However, there are still some shortcomings in actual use:

[0004] (1) The trigger mechanism lacks a locking structure, resulting in the risk of accidental release during transportation;

[0005] (2) Some connection structures are unreliable or difficult to manufacture;

[0006] (3) Some actions are not performed completely, such as incomplete injection of medicine, which causes some inconvenience;

[0007] Therefore, it is necessary to further improve the structure of the automatic injection pen in order to obtain an automatic injection pen with a more reliable structure and more thorough use of medicines to meet the storage, transportation and use requirements of medicines in disposable syringes. Summary of the invention

[0008] The object of the present invention is to provide an automatic injection pen, which improves multiple structures in order to obtain an automatic injection pen with a more reliable structure and more thorough use of medicines.

[0009] To achieve the above-mentioned purpose, the present invention provides an automatic injection pen, comprising an outer shell, a hidden needle cover, an inner cover, and a syringe assembly; the hidden needle cover is slidably installed in the outer shell; a piston activation port is provided on the top of the hidden needle cover; a lower spring cover is fixed to the inner side of the lower part of the hidden needle cover; a lower spring hook protruding inward is provided on the upper part of the lower spring cover; the inner cover is slidably installed in the hidden needle cover; an activation window is provided on the top of the inner cover; a slide groove is provided on the outer side of the lower part of the inner cover, the bottom of the slide groove is closed, and a convex card platform is provided on the upper part of the slide groove; the lower spring hook is clamped in the slide groove; a needle retracting spring is provided between the lower part of the inner cover and the lower spring cover; the syringe assembly comprises a syringe, a needle, and a piston assembly; the syringe The syringe is installed in the inner sleeve; a needle is installed at the bottom of the syringe; a piston assembly is arranged in the upper part of the syringe; the piston assembly comprises, from bottom to top, a pushing head, a pushing rod, a spring supporting part, a locking protrusion, an excitation guide part, and an excitation head in sequence; a rebound trigger claw is also arranged on the outer side of the pushing rod part; the locking protrusion is pre-clamped on the excitation window at the top of the inner sleeve, a medicine pushing spring is arranged on the outer side of the spring supporting part, and the medicine pushing spring is pre-compressed and pressed against the inner top of the inner sleeve; the excitation guide part pre-passes through the piston excitation port at the top of the hidden needle sleeve; a trigger claw passing window is arranged on the lower part of the inner sleeve, and the rebound trigger claw is located directly above the trigger claw passing window; the rebound trigger claw is also located directly above the lower spring hook;

[0010] The locking and triggering mechanism includes a piston assembly, a medicine pushing spring, an upper spring cylinder, a hidden needle sleeve, and a pen tube plug;

[0011] A spring support portion is provided on the upper part of the piston assembly, and the spring support portion is a pair of elastic claws; the outer side of the spring support portion is used to store the medicine pushing spring; and a locking excitation structure is provided on the upper part of the spring support portion;

[0012] The locking and activating structure on the upper part of the piston assembly comprises a spring locking slot, a piston locking slot, and an activating column;

[0013] The spring locking slot is located at the middle and upper part of the spring support part, and the piston locking slot is located at the upper part of the spring support part; the excitation column is located at the outer side of the middle and upper part of the spring support part;

[0014] The medicine pushing spring is a compression spring; the upper spring tube is arranged outside the medicine pushing spring;

[0015] The upper end of the medicine pushing spring abuts against the inner side of the top of the upper spring tube, and the lower end of the medicine pushing spring abuts against the bottom platform of the spring support part;

[0016] The top of the upper spring cylinder is provided with a piston excitation channel, and the inner side of the piston excitation channel is provided with a spring locking buckle;

[0017] The outer side of the upper spring cylinder is sleeved with the hidden needle sleeve which can move axially;

[0018] The top of the hidden needle sleeve is provided with a piston through-hole; the inner side of the hidden needle sleeve is provided with a piston activation guide plate;

[0019] The inner side of the piston activation guide plate is provided with an activation slope;

[0020] The pen tube plug is arranged on the outer side of the hidden needle sleeve;

[0021] A pen tube locking claw is provided inside the pen tube plug, and a pen tube locking hook is provided inwardly at the bottom of the pen tube locking claw;

[0022] The locking and activating mechanism includes a locking state and an activating state;

[0023] The locking state of the locking triggering mechanism is:

[0024] The upper part of the spring support part passes through the piston excitation channel at the top of the upper spring cylinder and the piston through-hole at the top of the hidden needle sleeve, and the piston locking groove is inserted into the pen tube locking claw of the pen tube plug and matched with the pen tube locking hook;

[0025] The middle and upper part of the spring support part is clamped on the top of the upper spring tube, and the spring locking groove is clamped into the spring locking buckle of the upper spring tube;

[0026] The medicine pushing spring is in a restricted compression state;

[0027] The hidden needle sleeve is in the lower position, the piston activation guide plate inside the hidden needle sleeve is located outside the spring support portion; and the activation slope of the piston activation guide plate is located directly below the activation column;

[0028] The excitation state of the locking excitation mechanism is:

[0029] The hidden needle sleeve is in the upper position, the piston activation guide plate moves upward along the outer side of the spring support part, the excitation slope contacts the excitation column, and the excitation column is guided to move inward, driving the upper part of the spring support part to retract inward;

[0030] And the excitation column gradually moves to the bottom free space of the excitation slope;

[0031] The piston locking groove moves inwards and disengages from the pen tube locking hook;

[0032] The spring locking slot moves inwardly and disengages from the spring locking buckle;

[0033] The medicine pushing spring is in a state of elastic release;

[0034] The piston rod of the piston assembly is provided with a protrusion at the part located in the syringe barrel; the protrusions are symmetrically arranged on both sides of the piston assembly;

[0035] A linear buffer is provided between the push head portion of the piston assembly and the piston in the syringe;

[0036] A trigger claw excitation inner support is provided in the trigger claw passing window; the trigger claw excitation inner support is connected with the convex card platform;

[0037] The outer surface of the inner support stimulated by the trigger claw is lower than the outer surface of the convex card platform.

[0038] As a further improvement of the present invention, the piston activation guide plates are provided with two, which are symmetrically arranged at the inner bottom of the piston through-hole;

[0039] The piston activation guide plate on each side is symmetrically provided with an activation slope;

[0040] There are four excitation columns, which are respectively located on both sides of the spring support parts at both sides;

[0041] Each of the excitation columns matches one of the excitation slopes.

[0042] Furthermore, a connecting plate is provided between the piston activation guide plates on both sides.

[0043] As a further improvement of the present invention, a piston locking post is provided in the piston passing opening at the top of the hidden needle sleeve;

[0044] When the locking trigger mechanism is in a locked state, the piston locking clamp is located in the middle of the spring support parts on both sides;

[0045] When the locking activation mechanism is in an activated state, the piston locking clamp is located above the spring support portion.

[0046] Furthermore, a connecting plate is provided between the piston locking column and the piston activation guide plate.

[0047] Furthermore, a locking column unlocking guide groove is provided on the inner side of the upper middle of the spring support portion;

[0048] The clamping column unlocking guide groove cooperates with the piston locking clamping column.

[0049] As a further improvement of the present invention, a pen tube limiting claw is provided on the outer side of the pen tube locking claw, and the pen tube limiting claw is a straight blocking piece;

[0050] Limiting planes are provided on both sides of the piston locking groove;

[0051] The limiting plane cooperates with the pen tube limiting claw.

[0052] Furthermore, a connecting plate channel is provided in the middle of the pen tube limiting claw.

[0053] As a further improvement of the present invention, a limit baffle is provided in the spring locking slot, and a limit slot is provided in the middle of the spring locking buckle;

[0054] When the spring locking slot and the spring locking buckle are matched together, the limiting baffle is locked in the limiting slot.

[0055] In the locking and activating mechanism of the present invention, the hidden needle sleeve is the only activating component, which can move upward to be activated.

[0056] As a further improvement of the present invention, the protrusion is integrally formed with the piston assembly;

[0057] The outer diameter of the protrusion is larger than the inner diameter of the syringe;

[0058] A cavity is formed inside the protrusion, and the protrusion has lateral elasticity.

[0059] As a further improvement of the present invention, the linear buffer includes a shell and a buffer plug;

[0060] The bottom of the shell is connected to the piston, and the top of the buffer plug is connected to the push head;

[0061] A sealing ring is arranged between the shell and the upper part of the buffer plug, and the sealing ring performs sliding sealing on the connection part;

[0062] A first buffer cavity is formed between the bottom of the buffer plug and the bottom of the inner cavity of the shell;

[0063] A depression is provided in the middle of the buffer plug, and a second buffer cavity is formed between the buffer plug and the inner wall of the shell sleeve;

[0064] A small connecting channel is provided between the first buffer cavity and the second buffer cavity;

[0065] Before use, inject a proper amount of buffer fluid into the first buffer cavity.

[0066] As a further improvement of the present invention, a guiding slope is provided on the top of the inner support that is stimulated by the trigger claw.

[0067] As a further improvement of the present invention, a protection sleeve is provided on the inner side of the pen cap, and a groove is provided on the upper part of the protection sleeve;

[0068] The grooves are provided in a plurality along the upper outer circumference of the sheathing tube;

[0069] The upper part of the protection removal sleeve is in an open state and has elasticity.

[0070] As a further improvement of the present invention, a protective sleeve is provided on the inner side of the pen cap, and a fixing buckle structure is provided on the lower part;

[0071] The lower part of the sheath extraction tube is hollowed out, an elastic clamping claw is arranged in the hollow cavity, and a clamping claw protrusion is arranged below the elastic clamping claw;

[0072] The elastic claws are provided with two pieces, which are arranged oppositely at the lower part of the sheath extraction tube;

[0073] The claw protrusion is arranged outwardly and exceeds the outer surface wall of the sheath extraction tube;

[0074] The upper and lower parts of the claw protrusion form guiding inclined surfaces;

[0075] A clamping protrusion is provided inwardly at the bottom of the protruding sleeve below the hidden needle sleeve;

[0076] When the pen cap is assembled with the injection pen body, the clamping protrusion passes over the highest convex point from above the elastic clamping claw and reaches below the elastic clamping claw, and the elastic clamping claw is elastically reset to press against the clamping protrusion of the hidden needle sleeve.

[0077] As a further improvement of the present invention, an elastic fixing buckle is provided on the lower spring sleeve, and three sides of the elastic fixing buckle are hollowed out, and only the bottom is connected to the main body of the lower spring sleeve;

[0078] The upper part of the elastic fixing buckle is a supporting limit part, which protrudes into the lower spring sleeve fixing opening of the hidden needle sleeve in a natural state;

[0079] A guiding inclined surface is provided downwardly and inwardly below the support limiting portion;

[0080] A bottom support is provided on the hidden needle sleeve.

[0081] The automatic injection pen of the present invention has made the following improvements compared to previous designs:

[0082] (1) The structure of the pen cap itself has been improved, which not only facilitates installation, but also improves the connection reliability before use and the reliability of the storage and transportation process;

[0083] (2) The trigger mechanism has been improved by adding a locking mechanism when not in use to ensure that the trigger mechanism will not loosen and trigger the spring when not in use, causing premature triggering and release of the drug;

[0084] (3) The piston rod of the piston assembly is improved and an elastic structure is added, so that the drug push injection is later than the needle insertion action, and the actions after the drug push spring is released present an obvious sequence, thereby improving the safety of drug injection;

[0085] (4) A linear buffer is provided between the push head of the piston assembly and the piston in the syringe to delay the occurrence of the needle retraction action, which can ensure that the medicine is injected cleanly and improve the utilization rate of the medicine, and also provide a certain pause time after the injection of the medicine is completed to meet the injection requirements;

[0086] (5) A trigger claw excitation inner support is provided in the trigger claw passage window to provide support for the trigger claw excitation process, thereby improving the reliability of the needle retraction triggering process;

[0087] (6) The connection structure between the hidden needle sleeve and the lower spring sleeve is improved so that it is convenient for installation during industrial production and can be fully and reliably locked to prevent loosening.

[0088] The automatic injection pen of the present invention has a more reliable structure, uses medicine more thoroughly, and can better meet the storage, transportation and use requirements of medicine in a disposable syringe. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] Figure 1 This is a diagram of the overall structure of the automatic injection pen of the present invention when it is not in use;

[0090] Figure 2 It is a cross-sectional view of the overall structure of the automatic injection pen of the present invention when it is not in use;

[0091] Figure 3 This is a schematic diagram of the structure of the automatic injection pen of the present invention when it is ready for use (the process of pulling out the pen cap);

[0092] Figure 4 This is a schematic diagram of the structure of the automatic injection pen of the present invention when it is ready for use (after the pen cap is removed);

[0093] Figure 5 It is a schematic diagram of the internal structure of the pen cap of the automatic injection pen of the present invention;

[0094] Figure 6 is an internal cross-sectional view of the pen cap of the automatic injection pen of the present invention;

[0095] Figure 7 It is a schematic diagram of the fixing structure of the pen cap of the present invention;

[0096] Figure 8 It is a schematic diagram of the inner structure of the pen tube plug of the present invention;

[0097] Fig. 9 It is a schematic diagram of the overall structure of the hidden needle sleeve of the present invention;

[0098] Fig.10 It is a cross-sectional view of the upper inner side of the hidden needle sleeve of the present invention;

[0099] Fig.11 It is a schematic diagram of the overall structure of the piston assembly of the present invention;

[0100] Fig.12 It is a schematic diagram of the upper structure of the piston assembly of the present invention;

[0101] Fig.13 It is a schematic diagram of the combination process state 1 of the piston assembly and the upper spring cylinder;

[0102] Fig.14 It is a schematic diagram of the combination process state 2 of the piston assembly and the upper spring cylinder;

[0103] Fig.15 It is a schematic diagram of the internal structure in a locked state;

[0104] Fig.16 It is a schematic diagram of a local combined structure in a locked state;

[0105] Fig.17 A partial schematic diagram of the unlocking process (not unlocked);

[0106] Fig.18 To stimulate the unlocking process (unlocked) overall internal schematic diagram;

[0107] Fig.19 , Fig. 20 It is a schematic diagram of the anti-rotation structure of the spring locking slot;

[0108] Fig.21 , Fig. 22 It is a schematic diagram of the anti-rotation structure of the piston locking groove;

[0109] Fig.23 , Fig.24 It is a structural schematic diagram of the connecting plate channel;

[0110] Fig.25 FIG. 1 is a schematic diagram of the overall structure of the piston assembly of the present invention. Fig.11 , but with different annotations;

[0111] Fig.26 It is a schematic diagram of the assembly state of the piston rod part of the present invention in the syringe;

[0112] Fig. 27 It is a schematic diagram of the installation of the linear buffer of the present invention;

[0113] Fig.28 It is a schematic diagram of the specific structure of the linear buffer of the present invention;

[0114] Fig.29 It is a schematic diagram of the arrangement of the trigger claw stimulating the inner support of the present invention;

[0115] Fig.30 It is a schematic diagram of the use state of the trigger claw of the present invention stimulating the inner support;

[0116] Fig.31 The schematic diagram of the connection structure between the hidden needle sleeve and the lower spring sleeve of the present invention is shown in FIG. Figure 1 ;

[0117] Fig.32 The schematic diagram of the connection structure between the hidden needle sleeve and the lower spring sleeve of the present invention is shown in FIG. Figure 2 ;

[0118] Fig.33 The working process of the present invention is shown in FIG. Figure 1 , showing the unlocking process of the unlocked excitation;

[0119] Fig.34 The working process of the present invention is shown in FIG. Figure 2 , showing the unlocked excitation unlocking process;

[0120] Fig.35 The working process of the present invention is shown in FIG. Figure 3 , showing the acupuncture process;

[0121] Fig.36 The working process of the present invention is shown in FIG. Figure 4 , showing the injection process;

[0122] Fig.37 The working process of the present invention is shown in FIG. Figure 5 , showing the working process of the linear buffer after the injection is completed;

[0123] Fig.38 The working process of the present invention is shown in FIG. Figure 6 , showing the needle collection process after the injection is completed;

[0124] Main reference numerals: syringe 11, needle 12; pen tube body 21; pen tube plug 22; pen cap 23;

[0125] Hidden needle sleeve 3; piston assembly 4; medicine pushing spring 51, needle retracting spring 52;

[0126] Upper spring cylinder 6; syringe sleeve 7; lower spring sleeve 8; syringe guard ring 9. DETAILED DESCRIPTION

[0127] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0128] The present invention is a structural improvement of the automatic injection pen with Chinese patent publication number CN113499513A; the names of the parts marked in the drawings of the present application can refer to the reference numerals in the drawings of Chinese patent publication number CN113499513A; Figure 1 This is a diagram of the overall structure of the automatic injection pen of the present invention when it is not in use. Figure 2It is a cross-sectional view of the overall structure of the automatic injection pen of the present invention when it is not in use; Figure 3 , Figure 4 This is a schematic diagram of the structure of the automatic injection pen of the present invention when it is ready for use; the overall structure of the automatic injection pen of the present invention remains similar, but many details are improved.

[0129] Improvement 1: Improve the pen cap 23.

[0130] (1) Improvement of the upper part of the pull-out sleeve 236. A groove 2361 is provided in the upper part of the pull-out sleeve 236 (see Figure 3 ), further as Figure 5 , Figure 6 As shown, a plurality of grooves 2361 are provided along the upper outer circle of the shield pulling tube 236, so that the upper part of the shield pulling tube 236 is in an open state and has a certain elasticity; during assembly, when docking with the shield of the syringe needle, the wall of the shield pulling tube 236 can be opened outward to facilitate the entry of the shield; after the shield enters, it can be restored to a tubular shape due to the elastic force of the material, and the shield can be clamped by the shield clamping protrusion. At that time, the shield of the needle can be removed together with the action of pulling out the pen cap 23.

[0131] (2) Improvement of the lower part of the sheath tube 236. In the automatic injection pen of Chinese patent publication number CN113499513A, the pen cap 23 is only connected to the clamping protrusion on the pen tube body 21 by a clamping groove, and there is no connection and fixing structure at the lower part, which may cause the risk of falling off. Therefore, the present application sets a fixing buckle structure at the lower part of the sheath tube 236. Specifically, as shown in FIG. Figure 5 , Figure 6 As shown, the present application forms a hollow at the lower part of the extraction sleeve 236, and an elastic claw 2362 is provided in the hollow cavity, and a claw protrusion 2363 is further provided below the elastic claw 2362; the elastic claw 2362 is preferably provided with two, which are relatively arranged at the lower part of the extraction sleeve 236, and the claw protrusion 2363 is arranged outward, exceeding the outer surface wall of the extraction sleeve 236; the upper and lower parts of the claw protrusion 2363 form guiding slopes. Figure 7 As shown, a sleeve 31 protrudes below the hidden needle sleeve 3 (when not in use, it protrudes from the pen tube body 21, as shown in FIG. Figure 3 , Figure 4The bottom of the cap 23 is provided with a clamping protrusion 311 inwardly; when the pen cap 23 is assembled with the injection pen body, the clamping protrusion 311 passes over the highest convex point from the top of the elastic claw 2362 and reaches the bottom of the elastic claw 2362. The elastic claw 2362 is reset by the elastic force of the material and presses against the clamping protrusion 311 of the hidden needle sleeve 3; at this time, the top of the cap 23 is mechanically limited by the pen tube body 21, and the bottom is limited by the clamping protrusion 311 of the hidden needle sleeve 3. Preferably, at this time, the elastic claw 2362 is compressed inwardly, thereby providing an outward elastic force to the clamping protrusion 311, and under the action of the inclined surface below the elastic claw 2362, a downward component force is further generated on the clamping protrusion 311, so that the cap 23 can be more reliably maintained. Figure 1 , Figure 2 In the unused state shown, the pen cap 23 is kept fixed; when the pen cap 23 needs to be removed, the clamping protrusion 311 can also cross the clamping protrusion 311 again under the action of external force, restore the free state, and make the hidden needle sleeve 3 and the pen cap 23 separate.

[0132] Improvement 2: Improve the locking trigger mechanism.

[0133] The locking and triggering mechanism mainly includes: the inner upper part of the pen tube plug 22, the hidden needle sleeve 3, the upper part of the piston assembly 4, the medicine pushing spring 51, and the upper spring cylinder 6.

[0134] (1) Pen tube plug 22

[0135] like Figure 8 As shown, a locking and limiting mechanism is provided at the upper inner part of the pen tube plug 22, including a pen tube locking claw 221; a pen tube locking hook 222 is provided inwardly at the bottom of the pen tube locking claw 221; the pen tube locking claws 221 are arranged opposite to each other, and pen tube limiting claws 223 are also provided on both sides thereof, and the pen tube limiting claws 223 are straight blocking pieces.

[0136] (2) Hidden needle sleeve 3

[0137] like Fig. 9 As shown, the hidden needle cover 3 has a more complex internal structure and adopts a split design, which is divided into a hidden needle structure 31 and an excitation structure 32; at the top of the hidden needle cover 3, there is still an opening similar to the piston excitation port, but it is a piston through port 321; and the interior of the excitation structure 32 is as shown in FIG. Fig.10 As shown, it includes a piston locking column 322 and a piston activation guide plate 323.

[0138] The piston locking clamp column 322 is located in the middle of the piston through-holes 321 on both sides; the piston activation guide plates 323 are preferably provided with two, symmetrically arranged on both sides of the piston locking clamp column 322; an activation slope 3231 is provided on the inner side of the piston activation guide plate 323, which is preferably symmetrically arranged on each side of the piston activation guide plate 323, and preferably symmetrically arranged relative to the piston locking insert 322. A connecting plate 324 is provided between the two sides of the piston activation guide plates 323 for connection and reinforcement; the top of the connecting plate 324 is further connected to the piston locking clamp column 322 for reinforcement.

[0139] (3) Piston assembly 4

[0140] like Fig.11 , Fig.12 As shown, the piston assembly 4 still includes a push head, a piston rod, a push rod, and a return trigger claw and other structures at the bottom. The platform formed on the top of the push rod and the return trigger claw is still provided with a spring support part 44; the spring support part 44 is still a pair of elastic claws, the outside of which can be used to store the medicine pushing spring 51, and the upper part is a locking excitation structure.

[0141] The upper locking and excitation structure of the piston assembly 4 includes a spring locking slot 45 , a piston locking slot 46 , and an excitation column 47 .

[0142] The piston locking slot 46 is used to cooperate with the pen tube locking claw 221 of the pen tube plug 22, and lock the piston assembly 4 in the shell of the automatic injection pen when it is not activated; the piston locking slot 46 includes a groove body 461, which cooperates with the pen tube locking hook 222; and a card-in guide inclined surface 462 is provided on the upper part of the groove body 461 for guidance during assembly.

[0143] The inner side of the upper middle of the piston assembly 4 is preferably provided with a post unlocking guide groove 48 , which cooperates with the piston locking post 322 .

[0144] (4) Upper spring tube 6

[0145] like Fig.13 , Fig.14 As shown, the upper spring tube 6 is still combined with the upper part of the piston assembly 4, and the medicine pushing spring 51 is arranged between the two; the top of the upper spring tube 6 is provided with a piston excitation channel 61, and the inner side thereof is provided with a spring locking buckle 62; the upper part of the piston assembly 4 passes through the piston excitation channel 61, and the spring locking groove 45 cooperates with the spring locking buckle 62 to achieve clamping, thereby connecting the piston assembly 4 and the upper spring tube 6 together.

[0146] like Fig.15As shown, it is a schematic diagram of the internal structure in the locked state, and the parts from the inside to the outside are the piston assembly 4, the medicine pushing spring 51, the upper spring cylinder 6, the hidden needle sleeve 3, and the pen tube plug 22.

[0147] The spring support portion 44 of the piston assembly 4 is covered with the medicine pushing spring 51 , and an upper spring tube 6 is provided on the outer side of the medicine pushing spring 51 ; the upper and lower ends of the medicine pushing spring 51 respectively abut against the inner side of the top of the upper spring tube 6 and the bottom of the spring support portion 44 .

[0148] The spring locking groove 45 of the spring support portion 44 is buckled with the spring locking buckle 62 to combine the piston assembly 4 with the upper spring tube 6 so that the medicine pushing spring 51 remains in a compressed state.

[0149] The upper portion of the spring support portion 44 passes through the piston excitation channel 61 and the piston through-port 321 in sequence, and then is inserted into the locking and limiting mechanism of the pen tube plug 22, so that the piston locking groove 46 is fastened with the pen tube locking claw 221, and the piston assembly 4 is combined with the pen tube plug 22, so that the components in the hidden needle sleeve 3 are fixed to the lower part of the pen tube plug 22.

[0150] Furthermore, in the locked state, the piston locking column 322 is inserted into the spring support portion 44 and retained in the column unlocking guide groove 48, so that the upper portion of the spring support portion 44 remains in an outwardly opened state, and the above-mentioned two snap interfaces remain in a reliably clamped state to prevent them from being disengaged, unlocked, or activated during storage and transportation.

[0151] At this time, the hidden needle sleeve 3 is the only activation component, which can move upward to be activated.

[0152] Further, if Figure 16-18 As shown, the activation process and principle of the hidden needle sleeve 3 are as follows:

[0153] (1) Early stage of activation; that is, when the automatic injection pen of the present invention is used, the bottom of the hidden needle cover 3 is pressed against the injection site, and then the injection pen applies force downward to move the hidden needle cover 3 upward relative to the housing and the internal structure; the piston locking column 322 of the hidden needle cover 3 moves upward along the column unlocking guide groove 48 until it is completely moved out of the upper area of ​​the spring support portion 44. Since there is no longer any restriction from the piston locking column 322, the upper part of the spring support portion 44 can be retracted and deformed inward at this time;

[0154] The upper sides of the spring support portion 44 are provided with excitation columns 47 which correspond to the excitation slope 3231 on the piston activation guide plate 323 ; at this time, the piston activation guide plate 323 also moves upward, so that the excitation slope 3231 and the excitation column 47 are getting closer and closer.

[0155] (2) Excitation process: the excitation column 47 contacts the excitation slope 3231, so that the excitation column 47 drives the upper part of the spring support portion 44 to retract inward along the excitation slope 3231; during this process, the spring locking groove 45 and the piston locking groove 46 also retract inward; thereby, the spring locking groove 45 begins to disengage from the spring locking buckle 62, and the piston locking groove 46 begins to disengage from the pen barrel lock hook 222;

[0156] (3) Pen stimulation; e.g. Fig.18 As shown, since the piston locking slot 46 is located at the upper part, its contraction amount is greater, and it will be separated from the pen tube lock hook 222 first, so that the spring support part 44 is no longer in contact with the pen tube plug 22; and as the spring locking slot 45 is completely separated from the spring locking buckle 62, the spring support part 44 is no longer fixed to the upper spring tube 6; and the excitation column 47 also moves to the bottom of the excitation slope 3231, and is separated from the excitation slope 3231, and is in a free state;

[0157] At this time, the compression force of the medicine pushing spring 51 begins to be released, pushing the piston assembly 4 downward, and starting the acupuncture, injection and other actions.

[0158] As a further improvement of the present invention, Fig.19 As shown in FIG. 4 , a limit baffle 451 is provided in the spring locking slot 45. Fig. 20 As shown, a limiting groove 621 is opened in the middle of the spring locking buckle 62; when the spring locking slot 45 is matched with the spring locking buckle 62, the limiting baffle 451 is inserted into the limiting groove 621, which can offset the circumferential rotation force and prevent the piston assembly 4 from rotating in the upper spring tube 6.

[0159] As a further improvement of the present invention, Fig.21 As shown in the figure, the two sides of the piston locking groove 46 are provided with limiting planes 463, which are aligned with the pen tube limiting claws 223 (as shown in the figure). Fig. 22 When the piston locking groove 46 cooperates with the pen tube locking hook 222, the pen tube limiting claw 223 blocks the limiting plane 463, which can offset the circumferential rotation force and prevent the piston assembly 4 from rotating in the pen tube plug 22.

[0160] As a further improvement of the present invention, Fig.23 As shown in the figure, a connecting plate channel 224 is opened in the middle of the pen tube limit claw 223; when the hidden needle sleeve 3 moves upward relatively due to the need for stimulation, the piston locking clamp column 322 (such as Fig.24As shown in the figure, the pen tube locking claw 221 enters the cavity formed by the pen tube limiting claw 223, and the connecting plate 324 is inserted into the connecting plate channel 224 opened in the middle of the pen tube limiting claw 223, and passes through it without any obstacles.

[0161] By improving the structure of the locking and triggering mechanism, when the automatic injection pen of the present invention is not in use, the pen tube plug 22, the upper spring tube 6, and the piston assembly 4 are connected together, and the locking is more reliable, and there will be no accidental triggering, thereby causing the drug pushing spring 51 to be released; and the triggering is performed by moving the hidden needle cover 3 upward, and the operation is still simple and easy to operate.

[0162] Improvement three: Improve the lower structure of the piston assembly 4.

[0163] like Fig.25 As shown, the lower part of the piston assembly 4, the part located inside the syringe barrel 11, i.e., the lower part of the piston rod 42, is provided with protrusions 421, preferably symmetrically arranged on both sides of the piston assembly 4; the protrusions 421 are preferably formed by the material of the piston assembly 4 itself during injection molding. The outer diameter of the protrusion 421 is greater than the inner diameter of the syringe barrel 11. Preferably, the protrusion 421 has a certain elasticity; the elasticity of the protrusion 421 can be formed by forming a cavity 422 inside the protrusion 421, so that the protrusion 421 has an elastic space.

[0164] like Fig.26 As shown, when the lower part of the piston assembly 4 is installed in the syringe 11, the protrusion 421 is squeezed and deformed, and is tightly attached to the inner wall of the syringe 11. Since the inner wall of the syringe 11 is relatively smooth, the piston assembly 4 can still move in the syringe 11 under the elastic force of the medicine pushing spring 51 after it is released, so as to achieve medicine pushing injection; but due to the additional friction between the protrusion 421 and the inner wall of the syringe 11, after the medicine pushing spring 51 is released, it can first push the entire syringe and the piston assembly 4 downward together, so that the needle is inserted into the injection target, that is, the needle is given priority; then the medicine pushing spring 51 continues to release the elastic force, and then pushes the piston assembly 4 to move in the syringe 11, so as to perform medicine pushing injection.

[0165] Improvement 4: Improve the needle collection mechanism.

[0166] (1) Delay the needle closing action.

[0167] During the release of the medicine pushing spring 51, the medicine pushing injection will be realized, and after the injection is completed, the rebound trigger claw of the piston assembly 4 will be triggered to remove the needle; in the existing design, this part is carried out continuously, and even when the piston 111 that pushes the medicine has just moved to the end of the syringe 11, the rebound trigger claw of the piston assembly 4 must immediately trigger the lower spring hook of the lower spring sleeve 8, otherwise there will be interference in the mechanical structure, which may cause the medicine to be incompletely injected, and the needle will be removed without any pause time after the medicine pushing is completed, so that the medicine has not yet stayed stable in the human body and may be brought out with the needle removal action; therefore, corresponding structural improvements are needed to delay the needle removal action.

[0168] like Fig. 27 , Fig.28 As shown, a linear buffer is mainly provided between the pusher part 41 of the piston assembly 4 and the piston 111 in the syringe 11 to delay the occurrence of the needle retracting action.

[0169] The linear buffer includes a shell 411 and a buffer plug 412 . The bottom of the shell 411 is connected to the piston 111 , and the top of the buffer plug 412 is connected to the push head 41 .

[0170] A sealing ring 413 is arranged between the shell 411 and the upper part of the buffer plug 412 to perform sliding sealing on the connection part. The seal therein is preferably capable of appropriately leaking air to the outside (exhaust) without causing obvious liquid leakage (no liquid discharge); a first buffer cavity 414 is formed between the bottom of the buffer plug 412 and the bottom of the inner cavity of the shell 411; a depression is provided in the middle part of the buffer plug 412, and a second buffer cavity 415 is formed between the inner wall of the shell 411; a small connecting channel is provided between the first buffer cavity 414 and the second buffer cavity 415.

[0171] Before use, an appropriate amount of buffer fluid 416 is injected into the first buffer cavity 414; the buffer fluid 416 is a high-viscosity fluid, and its viscosity is greater than that of the medicine.

[0172] When the medicine pushing spring 51 is released and the medicine is pushed and injected, the spring force is applied to the piston assembly 4, and the thrust is transmitted to the buffer plug 412 by the pushing head part 41; the buffer plug 412 mainly squeezes the buffer fluid 416 in the first buffer cavity 414, and then transmits the thrust to the shell 411, and finally pushes the piston 111 to move in the syringe 11 to push the medicine; at this time, the buffer fluid 416 will also flow slowly into the second buffer cavity 415 under the action of the thrust, but the flow speed is slower than the injection speed of the medicine, so the force is mainly used for pushing the medicine for injection.

[0173] When the medicine pushing spring 51 is released in the later stage, until the medicine is completely injected, the piston 111 reaches the end of the syringe 11; the spring force continues to act, and continues to push the buffer plug 412 to move, and the buffer fluid 416 in the first buffer chamber 414 is completely discharged into the second buffer chamber 415 until it is completely discharged. At this time, the rebound trigger claw of the piston assembly 4 contacts the lower spring hook of the lower spring sleeve 8, opening it so that the needle retracting spring 52 is released, and the needle retracting operation is started.

[0174] During the transfer of the buffer fluid 416 in the first buffer chamber 414 to the second buffer chamber 415, the gas in the second buffer chamber 415 can be discharged outward through the sealing gap at the sealing ring 413, which will further produce an effect similar to air damping; when the buffer fluid 416 completely enters the second buffer chamber 415, the buffer fluid 416 is difficult to leak through the sealing gap at the sealing ring 413 due to its relatively large viscosity, so that this part is in a relatively stable state.

[0175] By providing the linear buffer, on the one hand, it can ensure that the medicine is completely injected, and a buffer period is formed from the completion of the medicine injection to the start of needle withdrawal, which delays the needle withdrawal and meets the pause requirement after injection.

[0176] (2) Improve the trigger reliability of the needle closing action. Fig.29 As shown, the structure of the syringe sleeve 7 is partially improved. Specifically, a trigger claw excitation inner support 79 is provided in the trigger claw passing window 75; the trigger claw excitation inner support 79 is connected with the convex clamping platform 74 and other structures, and has good structural rigidity; the outer surface of the trigger claw excitation inner support 79 is lower than the outer surface of the convex clamping platform 74. The top of the trigger claw excitation inner support 79 can also be provided with a guiding inclined surface 791 for guiding the rebound trigger claw 49 when entering. Fig.30 As shown, when the rebound trigger claw 49 of the piston assembly 4 enters the trigger claw passing window 75 and contacts the inner side of the lower spring hook 85 of the lower spring sleeve 8, the trigger claw excites the inner support 79 against the inner side of the rebound trigger claw 49, so that the rebound trigger claw 49 can better push the lower spring hook 85 outward and leave the convex clamping platform 74, and then the needle spring 52 is released, and each component starts to move in the longitudinal direction, and finally the lower spring hook 85 elastically rebounds and enters the slide groove 73. By setting the trigger claw excitation inner support 79, the rebound trigger claw 49 can be fully utilized to push the lower spring hook 85 out; that is, it can be avoided that the rebound trigger claw 49 shrinks inward (the rebound trigger claw 49 is a cantilever structure) and cannot fully push the lower spring hook 85 outward and leave the convex clamping platform 74.

[0177] Improvement 5: Improve the connection structure between the hidden needle sleeve 3 and the lower spring sleeve 8.

[0178] The hidden needle sleeve 3 is connected to the lower spring sleeve 8 by a buckle; the lower spring sleeve fixing buckle originally designed to be arranged on the lower spring sleeve 8 is a straight buckle, which can only be installed through the elastic deformation of the material, and a large force needs to be applied during the installation process.

[0179] like Fig.31 , Fig.32 As shown in the figure, it is an improved connection structure, the lower spring sleeve 8 is provided with an elastic fixing buckle 82, the three sides of the elastic fixing buckle 82 are hollowed out, and only the bottom is connected to the main body of the lower spring sleeve 8; the upper part of the elastic fixing buckle 82 is a support limiter 821, which protrudes into the lower spring sleeve fixing port 33 of the hidden needle sleeve 3 in a natural state; the lower part of the support limiter 821 is provided with a guiding inclined surface downward and inward. At the same time, a bottom support 333 is provided on the hidden needle sleeve 3.

[0180] When the lower spring sleeve 8 is installed into the hidden needle sleeve 3, it is inserted from the top of the hidden needle sleeve 3, and the guiding inclined surface of the elastic fixing buckle 82 gradually contacts the hidden needle sleeve 3, so that the elastic fixing buckle 82 is forced to shrink inward until it reaches the position of the lower spring sleeve fixing port 33 and then pops out; at this time, the bottom of the lower spring sleeve 8 just rests on the bottom support 333; that is, the lower spring sleeve 8 is reliably installed in the hidden needle sleeve 3, and can reliably bear force in the upper and lower directions without slipping.

[0181] The use process of the automatic injection pen of the present invention can be referred to Figure 1-Figure 4 ,and Figure 33-Figure 38 ;

[0182] (1) Figure 1 , Figure 2 Not completely unused;

[0183] (2) Figure 3 Remove the pen cap and prepare for use;

[0184] Before use, the medicine pushing spring is in a compressed state and the needle retracting spring is in an expanded state;

[0185] (4) Figure 4 In the state of preparation for use, the operator grasps the pen tube body 21 with his hand, and then presses the bottom of the hidden needle cover 3 against the skin of the part to be injected, and then presses down hard to move the pen tube body 21 downward and against the skin of the part to be injected. Then the automatic injection pen of the present invention is activated and the automatic injection operation starts;

[0186] (5) Fig.33 As shown, the hidden needle sleeve 3 moves upward relatively, and starts to trigger the locking excitation mechanism; further reference may be made to Fig.17 ; With the movement of the hidden needle sleeve 3, the needle spring is compressed;

[0187] (6) Fig.34As shown, the spring support part shrinks inwards and no longer contacts the pen tube plug, the medicine pushing spring is in a free state and begins to release its elastic force; for further reference, Fig.18 ; The lower spring hook completely hooks the convex card platform, and the needle retracting spring is compressed to store energy;

[0188] (7) Fig.35 As shown, the medicine pushing spring is partially released; the friction between the protrusion at the lower part of the piston rod and the wall of the syringe acts to push the syringe downward, especially the needle, and insert it into the part to be injected;

[0189] (8) Fig.36 As shown, the medicine pushing spring is continuously released, overcoming the friction between the protrusion at the lower part of the piston rod and the wall of the syringe, and injecting the medicine in the syringe into the patient's body;

[0190] (9) Fig.37 As shown, when the medicine pushing spring is about to be released, the medicine in the syringe barrel is completely injected into the patient's body, and the linear buffer starts to work; then, the rebound trigger claw enters the trigger claw through the window, pushing the lower spring hook outward;

[0191] (10) Fig.38 As shown, the needle retraction spring is released, the needle is pulled out, and at the same time, the syringe and other components move upward as a whole, and finally the needle is completely hidden in the needle cover, completing the injection and needle removal.

[0192] The preferred embodiments of the present invention have been specifically described above, but the present invention is not limited to the described embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. An automatic injection pen, comprising a shell, a hidden needle cover, an inner cover, and a syringe assembly; the hidden needle cover is slidably installed in the shell; a piston activation port is provided on the top of the hidden needle cover; a lower spring cover is fixed to the inner side of the lower part of the hidden needle cover; a lower spring hook protruding inward is provided on the upper part of the lower spring cover; the inner cover is slidably installed in the hidden needle cover; an activation window is provided on the top of the inner cover; a slide groove is provided on the outer side of the lower part of the inner cover, the bottom of the slide groove is closed, and a convex card platform is provided on the upper part of the slide groove; the lower spring hook is clamped in the slide groove; a needle retracting spring is provided between the lower part of the inner cover and the lower spring cover; the syringe assembly comprises a syringe, a needle, and a piston assembly; the The syringe is installed in the inner sleeve; a needle is installed at the bottom of the syringe; a piston assembly is arranged in the upper part of the syringe; the piston assembly comprises, from bottom to top, a pushing head, a pushing rod, a spring supporting part, a locking protrusion, an excitation guide part and an excitation head in sequence; a rebound trigger claw is also arranged on the outer side of the pushing rod part; the locking protrusion is pre-clamped on the excitation window at the top of the inner sleeve, a medicine pushing spring is arranged on the outer side of the spring supporting part, and the medicine pushing spring is pre-compressed and pressed against the inner top of the inner sleeve; the excitation guide part pre-passes through the piston excitation port at the top of the hidden needle sleeve; a trigger claw passing window is arranged on the lower part of the inner sleeve, and the rebound trigger claw is located directly above the trigger claw passing window; The rebound trigger claw is located directly above the lower spring hook; It is characterized in that The locking and triggering mechanism includes a piston assembly, a medicine pushing spring, an upper spring cylinder, a hidden needle sleeve, and a pen tube plug; A spring support portion is provided on the upper part of the piston assembly, and the spring support portion is a pair of elastic claws; the outer side of the spring support portion is used to store the medicine pushing spring; and a locking excitation structure is provided on the upper part of the spring support portion; The locking and activating structure on the upper part of the piston assembly includes a spring locking slot, a piston locking slot, and an activating column; The spring locking slot is located at the middle and upper part of the spring support part, and the piston locking slot is located at the upper part of the spring support part; the excitation column is located at the outer side of the middle and upper part of the spring support part; The medicine pushing spring is a compression spring; the upper spring tube is arranged outside the medicine pushing spring; The upper end of the medicine pushing spring abuts against the inner side of the top of the upper spring tube, and the lower end of the medicine pushing spring abuts against the bottom platform of the spring support part; The top of the upper spring cylinder is provided with a piston excitation channel, and the inner side of the piston excitation channel is provided with a spring locking buckle; The outer side of the upper spring cylinder is sleeved with the hidden needle sleeve which can move axially; The top of the hidden needle sleeve is provided with a piston through-hole; the inner side of the hidden needle sleeve is provided with a piston activation guide plate; The inner side of the piston activation guide plate is provided with an activation slope; The pen tube plug is arranged on the outer side of the hidden needle sleeve; A pen tube locking claw is provided inside the pen tube plug, and a pen tube locking hook is provided inwardly at the bottom of the pen tube locking claw; The locking and activating mechanism includes a locking state and an activating state; The locking state of the locking triggering mechanism is: The upper part of the spring support part passes through the piston excitation channel at the top of the upper spring cylinder and the piston through-hole at the top of the hidden needle sleeve, and the piston locking groove is inserted into the pen tube locking claw of the pen tube plug and matched with the pen tube locking hook; The middle and upper part of the spring support part is clamped on the top of the upper spring tube, and the spring locking groove is clamped into the spring locking buckle of the upper spring tube; The medicine pushing spring is in a restricted compression state; The hidden needle sleeve is in the lower position, the piston activation guide plate inside the hidden needle sleeve is located outside the spring support portion; and the activation slope of the piston activation guide plate is located directly below the activation column; The excitation state of the locking excitation mechanism is: The hidden needle sleeve is in the upper position, the piston activation guide plate moves upward along the outer side of the spring support part, the excitation slope contacts the excitation column, and the excitation column is guided to move inward, driving the upper part of the spring support part to retract inward; And the excitation column gradually moves to the bottom free space of the excitation slope; The piston locking groove moves inwards and disengages from the pen tube locking hook; The spring locking slot moves inwardly and disengages from the spring locking buckle; The medicine pushing spring is in a state of elastic release; The piston rod of the piston assembly is provided with a protrusion at the part located in the syringe barrel; the protrusions are symmetrically arranged on both sides of the piston assembly; A linear buffer is provided between the push head portion of the piston assembly and the piston in the syringe; A trigger claw excitation inner support is provided in the trigger claw passing window; The trigger claw triggers the inner support to be connected with the convex card platform; The outer surface of the inner support stimulated by the trigger claw is lower than the outer surface of the convex card platform; The piston activation guide plates are provided with two, symmetrically arranged at the inner bottom of the piston through-hole; The piston activation guide plate on each side is symmetrically provided with an activation slope; There are four excitation columns, which are respectively located on both sides of the spring support parts at both sides; Each of the excitation columns matches one of the excitation slopes; A piston locking post is provided in the piston passing opening at the top of the hidden needle sleeve; When the locking trigger mechanism is in a locked state, the piston locking clamp is located in the middle of the spring support parts on both sides; When the locking excitation mechanism is in an excitation state, the piston locking clamping column is located above the spring support portion; a clamping column unlocking guide groove is provided on the inner middle side of the upper part of the spring support portion; The locking column unlocking guide groove cooperates with the piston locking column; A connecting plate is provided between the piston activation guide plates on both sides; A connecting plate is provided between the piston locking clamp and the piston activation guide plate.

2. The automatic injection pen according to claim 1, characterized in that: A pen tube limiting claw is provided on the outer side of the pen tube locking claw, and the pen tube limiting claw is a straight blocking piece; Limiting planes are provided on both sides of the piston locking groove; The limiting plane cooperates with the pen tube limiting claw.

3. The automatic injection pen according to claim 1, characterized in that: A limit baffle is provided in the spring locking slot, and a limit slot is provided in the middle of the spring locking buckle; When the spring locking slot and the spring locking buckle are matched together, the limiting baffle is locked in the limiting slot.

4. The automatic injection pen according to claim 1, characterized in that: The protrusion is integrally formed with the piston assembly; The outer diameter of the protrusion is larger than the inner diameter of the syringe; A cavity is formed inside the protrusion, and the protrusion has lateral elasticity.

5. The automatic injection pen according to claim 1, characterized in that: The linear buffer comprises a shell and a buffer plug; The bottom of the shell is connected to the piston, and the top of the buffer plug is connected to the push head; A sealing ring is arranged between the shell and the upper part of the buffer plug, and the sealing ring performs sliding sealing on the connection part; A first buffer cavity is formed between the bottom of the buffer plug and the bottom of the inner cavity of the shell; A depression is provided in the middle of the buffer plug, and a second buffer cavity is formed between the buffer plug and the inner wall of the shell sleeve; A small connecting channel is provided between the first buffer cavity and the second buffer cavity; Before use, inject a proper amount of buffer fluid into the first buffer cavity.

6. The automatic injection pen according to claim 1, characterized in that: A protection sleeve is provided on the inner side of the pen cap, and a groove is provided on the upper part of the protection sleeve; The grooves are provided in a plurality along the upper outer circumference of the sheathing tube; The upper part of the protection removal sleeve is in an open state and has elasticity.

7. The automatic injection pen according to claim 1, characterized in that: A protective sleeve is provided on the inner side of the pen cap, and a fixing buckle structure is provided at the lower part of the protective sleeve; The lower part of the sheath extraction tube is hollowed out, an elastic clamping claw is arranged in the hollow cavity, and a clamping claw protrusion is arranged below the elastic clamping claw; The elastic claws are provided with two pieces, which are arranged oppositely at the lower part of the sheath extraction tube; The claw protrusion is arranged outwardly and exceeds the outer surface wall of the sheath extraction tube; The upper and lower parts of the claw protrusion form guiding inclined surfaces; A clamping protrusion is provided inwardly at the bottom of the protruding sleeve below the hidden needle sleeve; When the pen cap is assembled with the injection pen body, the clamping protrusion passes over the highest convex point from above the elastic clamping claw and reaches below the elastic clamping claw, and the elastic clamping claw is elastically reset to press against the clamping protrusion of the hidden needle sleeve.

8. The automatic injection pen according to claim 1, characterized in that: An elastic fixing buckle is arranged on the lower spring sleeve, and three sides of the elastic fixing buckle are hollowed out, and only the bottom is connected to the main body of the lower spring sleeve; The upper part of the elastic fixing buckle is a supporting limit part, which protrudes into the lower spring sleeve fixing opening of the hidden needle sleeve in a natural state; A guiding inclined surface is provided downwardly and inwardly below the support limiting portion; A bottom support is provided on the hidden needle sleeve.

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