CN109646019B

CN109646019B - Improved tail pressing type disposable safety hemostix

Info

Publication number: CN109646019B
Application number: CN201910116879.9A
Authority: CN
Inventors: 施国平; 王祥生; 张金权
Original assignee: Sterilance Medical Suzhou Inc
Current assignee: Sterilance Medical Suzhou Inc
Priority date: 2019-02-15
Filing date: 2019-02-15
Publication date: 2021-07-20
Anticipated expiration: 2039-02-15
Also published as: CN109646019A

Abstract

The utility model provides a disposable safe hemostix of improved generation afterbody push type, includes shell, nook closing member, spring and tail-hood, its characterized in that: the tail cover is characterized in that an outer hook is designed on the side of the tail cover, a narrow groove, a wide groove, a transition inclined surface, a radial protrusion and other structures are designed on the inner wall of an accommodating cavity of the shell aiming at the outer hook, so that a rear end surface used for limiting the rear end, a transition inclined surface or an arc surface used for climbing and a locking end surface used for locking the front end are formed on the outer hook relative to the forward movement path of the accommodating cavity, under the state of waiting to be launched, the outer hook is hooked on the rear end surface, the tail cover is located at the position of limiting the rear end relative to the accommodating cavity, when the tail cover is pushed forwards, the outer hook climbs along the transition inclined surface or the arc surface until the radial protrusion is crossed, under the state after launching, the outer hook is hooked on the locking end surface of the radial protrusion, and the tail cover is located at the position of locking the front end relative to the accommodating cavity of the shell. The scheme solves the problem of low reliability of the original locking structure.

Description

Improved tail pressing type disposable safety hemostix

Technical Field

The invention relates to the field of medical blood sampling instruments, in particular to an improved tail pressing type disposable safety blood sampler. The hemostix improves the original hemostix, and improves the safety and reliability of disposable use.

Background

Among medical blood collection devices, disposable blood collection devices are popular among medical care personnel and patients due to the characteristics of small volume, safe use and convenient operation, and are widely used in various medical institutions and diabetics at present. The ejection mechanism of the hemostix is compact in structure, safe and convenient, and has strong market development potential, and the hemostix is integrally disposable.

Chinese patent CN108186029A discloses an invention patent application named "tail pressing type disposable safety blood collector". This patent design has initiative hasp portion on the tail-hood, and the design has passive hasp portion on the elastic arm to with the position and the cooperation time of initiative hasp portion and passive hasp portion, with the position and the cooperation time of initiative unlocking portion and passive unlocking portion relevance, press the tail-hood during the use, force the needle core unblock earlier, launch the puncture, then tail-hood and elastic arm get into the latch hook state, can't reuse. The technical scheme of the patent not only can embody the safety of disposable use, but also can easily identify the obviously retracted state of the tail cover after use from the appearance. However, in view of the locking structure of the patent, the locking structure is formed by matching an active locking part arranged on the tail cover with a passive locking part arranged on the elastic arm, and the locking structure belongs to a limit locking structure in nature, but not a dead locking structure. In other words, the locking structure is formed by the active locking portion interfering with the passive locking portion through the outward deformation of the resilient arm after the tail cover is pressed, and the reliability of the locking is low compared to the locking structure. After the use, when the twist cap is inserted into the blood collector from the front end to push the needle body, the spring is firstly forced to be compressed into rigidity, and then the tail cover is pushed to move backwards, so that the original locking structure is deformed and unlocked. Therefore, although the technical problem of the patent can be solved, the limit locking structure has the following defects: the reliability of locking is not high, and the locking is easy to lose efficacy, and the safety of one-time use cannot be ensured theoretically. Therefore, how to improve the reliability of the conventional locking structure of the blood sampling device is the subject of the present invention.

Disclosure of Invention

In view of the above disadvantages of the prior art, the present invention provides an improved tail-pressing type disposable safety blood collector, which aims to solve the problem of low reliability of the locking structure of the original tail-pressing type blood collector.

In order to achieve the purpose, the invention adopts the technical scheme that: an improved tail pressing type disposable safety hemostix, which comprises a shell, a needle core, a spring and a tail cover.

The shell forms an ejection cavity, the needle core is positioned in the ejection cavity, a locking structure is arranged between the needle core and the shell, and in a state to be ejected, the spring presses the needle core and positions and locks the needle core in the ejection cavity of the shell through the locking structure.

The tail cover is arranged at the tail part of the shell, and the tail cover is used as a key of the tail pressing type launching structure and is provided with an unlocking structure aiming at the locking structure.

The innovation lies in that: the tail part of the shell is provided with a containing cavity, the tail cover is arranged in the containing cavity, and the side part of the tail cover is provided with an outer hook which is folded towards the outer side.

Corresponding to the outer hook, a narrow groove and a wide groove are arranged on the inner wall of the accommodating cavity; the width of the narrow groove is smaller than that of the wide groove; the narrow groove is arranged at the axial rear part of the accommodating cavity, and the rear end of the narrow groove is open and communicated with the outside of the shell; the wide groove is arranged at the axial front part of the accommodating cavity, and the front end of the wide groove is open and is communicated with the outside of the shell; the front end of the narrow groove is communicated with the rear end of the wide groove, and the wide groove at the communication position is provided with a rear end face; the width of the outer hook is larger than that of the narrow groove and smaller than that of the wide groove.

And a radial bulge is arranged in the wide groove corresponding to the narrow groove, the front end of the radial bulge is provided with a locking end face, and a transition inclined face or an arc face is arranged from the rear part to the narrow groove.

The tail cover is in sliding fit with the containing cavity arranged at the tail of the shell in the axial direction, the outer hook is hooked on the rear end face of the wide groove in a to-be-launched state, the tail cover is located at a rear end limiting position relative to the containing cavity of the shell, the outer hook climbs along the transition inclined plane or the arc surface until the outer hook crosses the radial protrusion when the tail cover is pushed forwards, and the outer hook is hooked on the locking end face of the radial protrusion in a to-be-launched state, and the tail cover is located at a front end locking position relative to the containing cavity of the shell.

The relevant contents and variations of the above technical solution are explained as follows:

1. in the above scheme, the shell, the stylet, the spring and the tail cap are basic structures of the tail pressing type disposable blood collector, and the basic functions and functions of the tail pressing type disposable blood collector are the prior art.

2. In the above embodiment, the "front" of the "front end", "front portion", and "forward" refers to the direction of the needle tip in the blood collection device. The "rear" in the "rear end" and "rear portion" means the opposite direction of the "front". The "axial direction" refers to the axial direction of the blood collection device and also to the longitudinal direction of the blood collection needle in the blood collection device.

3. In the above scheme, the head of the shell can be additionally provided with an adjusting head structure, so that the puncture depth can be adjusted. This does not affect the achievement of the object of the invention.

4. The tail pressing type hemostix of the invention comprises a twist cap type structure and a cap type structure. Namely, the disposable hemostix of the present invention is usually provided with a protective cap, and the structural form of the protective cap can be a twist cap type or a cap type. This does not affect the achievement of the object of the invention.

The design principle and concept of the invention are as follows: in order to solve the problem of low reliability of the locking structure of the original tail pressing type hemostix (see background technical description), the invention adopts the technical concept that: the matching and motion relation between the tail cover and the shell in the hemostix structure is utilized, and the original limit locking structure (non-locking structure) designed between the tail cover and the elastic arm is changed into the locking structure between the tail cover and the containing cavity, so that the reliability of locking after the hemostix is launched is improved. The original limit locking structure (non-locking structure) can be kept and the pin can be taken out, and the pin can be confirmed by a designer according to specific conditions. However, in the present invention, the receiving cavity is a structure that the tail of the housing has a cavity and is integrally formed with the housing as a plastic piece, so that the technical personnel have difficulties in that: how to design a locking structure between the tail cover and the containing cavity, which not only meets the locking requirement of high reliability, but also can be formed in one step through a mould. Therefore, the outer hook is designed on the side part of the tail cover, structures such as a narrow groove, a wide groove, a transition inclined surface and a radial protrusion are designed on the inner wall of the accommodating cavity of the shell aiming at the outer hook, so that a rear end surface for rear end limiting, a transition inclined surface or an arc surface for climbing and a locking end surface for front end locking are formed on the forward moving path of the outer hook relative to the accommodating cavity, the outer hook is hooked on the rear end surface in a to-be-launched state, the tail cover is located at a rear end limiting position relative to the accommodating cavity, when the tail cover is pushed forwards, the outer hook climbs along the transition inclined surface or the arc surface until the outer hook crosses the radial protrusion, and in a launched state, the outer hook is hooked on the locking end surface of the radial protrusion, and the tail cover is located at a front end locking position relative to the accommodating cavity of the shell.

Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages and effects:

1. the invention changes the original limit locking structure (non-locking structure) designed between the tail cap and the elastic arm into the locking structure between the tail cap and the containing cavity, thereby improving the reliability of locking after the hemostix is launched. Overcome prior art's not enough, after the hemostix was used, when adopting to turn round the cap and insert inside from the hemostix front end and push away and support the needle body, can not produce the unblock. The tail cover is permanently locked in the accommodating cavity of the shell at the moment, and the safety of disposable use is guaranteed theoretically.

2. After the hemostix is used, the tail cover is obviously retracted relative to the containing cavity at the tail part of the shell, and the different shapes of the hemostix before and after use can be visually identified from the appearance. The effect is not only beneficial to the safe use of the hemostix, but also obtains better user experience effect.

3. In the invention, three important structures of the rear end face, the transition inclined face and the locking end face are combined by adopting structures such as a narrow groove, a wide groove, a radial protrusion and the like in order to facilitate the injection molding process, and the demolding difficulty of the injection molding process for forming the rear end face, the transition inclined face and the locking end face can be effectively solved by adopting special designs such as opening the rear end of the narrow groove and communicating with the outside of the shell, opening the front end of the wide groove and communicating with the outside of the shell. Therefore, the tail pressing type blood collector locking structure is reasonable in structural design and ingenious in technical conception, well solves the problem of low reliability of the tail pressing type blood collector locking structure, and has prominent substantive characteristics and remarkable progress compared with the prior art.

Drawings

FIG. 1 is a perspective view of a blood collection device according to an embodiment of the present invention;

FIG. 2 is an exploded perspective view of the blood collection device according to the embodiment of the present invention;

FIG. 3 is a perspective view of a housing from a first perspective according to an embodiment of the present invention;

FIG. 4 is a perspective view of a second perspective view of the housing in accordance with the present invention;

FIG. 5 is a perspective view of a hub and twist cap in accordance with an embodiment of the present invention;

FIG. 6 is an enlarged view of the core of FIG. 5;

FIG. 7 is a first perspective view of a tail cap according to an embodiment of the present invention;

FIG. 8 is a second perspective view of the tail cap according to the present invention;

FIG. 9 is a rear end elevational view of the housing of an embodiment of the present invention;

FIG. 10 is a rear end elevational view of the tail cap of an embodiment of the present invention;

FIG. 11 is a rear perspective view of a housing according to an embodiment of the present invention;

FIG. 12 is a rear perspective view of a tail cap according to an embodiment of the present invention;

FIG. 13 is a perspective view, partially in section, of the assembled housing and tail cap of an embodiment of the present invention;

FIG. 14 is an enlarged view at A of FIG. 13;

FIG. 15 is a cross-sectional view of an initial assembly of an embodiment of the present invention;

FIG. 16 is a cross-sectional view of an embodiment of the present invention with the twist cap removed and in a ready-to-fire condition;

FIG. 17 is a cross-sectional view of a tail cap in a pressed state according to an embodiment of the present invention;

FIG. 18 is a cross-sectional view of an embodiment of the invention in a fired state;

FIG. 19 is a cross-sectional view of an embodiment of the present invention in a post-launch condition;

FIG. 20 is a perspective view of the tail cap shown retracted after firing in accordance with an embodiment of the present invention.

The reference numerals in the above figures are explained as follows:

1. a housing; 2. a needle core; 3. a spring; 4. a tail cover; 5. a resilient arm; 6. a hook; 7. necking down; 8. a clamping surface; 9. a pinhole is formed; 10. unlocking the inclined plane; 11. twisting the cap; 12. an active unlocking part; 13. a passive unlocking portion; 14. an active locking part; 15. a torsion portion; 16. a guard bar; 17. a passive locking part; 18. a latch hook; 19. a locking surface; 20. an accommodating cavity; 21. an elastic sheet; 22. a narrow groove; 23. a wide groove; 24. an outer hook; 25. a through opening; 26. a rear end face; 27. a radial projection; 28. a locking end face; 29. a transition bevel.

Detailed Description

The invention is further described with reference to the following figures and examples:

example (b): improved tail pressing type disposable safety hemostix

The hemostix consists of a shell 1, a needle core 2, a twist cap 11, a spring 3 and a tail cover 4 (see figures 1 and 2).

The shell 1 forms an ejection cavity, the front end of the ejection cavity is provided with a pin outlet hole 9 (see fig. 3 and 4), and a notch (see fig. 4 and not labeled) is formed in the pin outlet hole 9. The stylet 2 is positioned in the ejection cavity, two elastic arms 5 (see fig. 3, 4, 9, 11 and 15) extend inwards from the shell 1, hooks 6 (see fig. 15 and 16) for locking the stylet 2 are arranged on the elastic arms 5, and a clamping surface 8 (see fig. 5, 6, 15 and 16) corresponding to the hooks 6 is arranged on the stylet 2. In the state of waiting to be shot, the front end of the spring 3 is pressed against the stylet 2, and the clamping surface 8 of the stylet 2 is pressed against the clamping hook 6 of the elastic arm 5, so that the stylet 2 is positioned and locked in the shooting cavity of the shell 1 (see fig. 16).

The stylet 2 and the twist cap 11 are integrally formed (see fig. 5 and 6), and thus the twist cap type push-type disposable blood collector with a tail is formed. The twist cap 11 is positioned at the front part of the stylet 2 and is connected with the stylet 2 into an integral injection molding structure, the twist cap 11 is formed by fixedly connecting a twist part 15 and a protection rod 16, and a twist-off shrinkage neck 7 is arranged between the protection rod 16 and the stylet 2 (see fig. 5 and 6).

The tail cover 4 (see fig. 7 and 8) is mounted at the tail of the shell 1 (see fig. 13, 14 and 15), the tail cover 4 is provided with an active unlocking part 12 (see fig. 7, 8 and 15), the active unlocking part 12 is provided with an action end, a passive unlocking part 13 (see fig. 15) is arranged on the elastic arm 5 corresponding to the active unlocking part 12, the passive unlocking part 13 is provided with an action end, the action end of the active unlocking part 12 is a corner of a bump (see fig. 7, 8 and 15), and the action end of the passive unlocking part 13 is an unlocking inclined surface 10 (see fig. 15).

In order to solve the problem of low reliability of the locking structure of the original tail pressing type hemostix, the invention designs the following locking structure between the tail cover 4 and the accommodating cavity 20 at the tail part of the shell 1:

a containing cavity 20 is arranged at the tail part of the shell 1 (see fig. 9, 11 and 13), the tail cover 4 is arranged in the containing cavity 20 (see fig. 13), two elastic sheets 21 are arranged at the side part of the tail cover 4, and the tail end of each elastic sheet 21 is provided with an outer hook 24 which is turned over towards the outer side (see fig. 7, 8, 10, 12, 14 and 15). The hook angle is designed to be 90 degrees or less in order to ensure reliability of the outer hook 24.

A narrow groove 22 and a wide groove 23 are formed on the inner wall of the receiving chamber 20 corresponding to each outer hook 24 (see fig. 11 and 14). The width of the narrow groove 22 is smaller than the width of the wide groove 23 (see fig. 11 and 14). The narrow groove 22 is disposed at the axial rear portion of the accommodation chamber 20, and the rear end of the narrow groove 22 is open and communicates with the outside of the housing 1 (see fig. 11 and 14). The wide groove 23 is disposed at the axial front portion of the accommodation chamber 20, and the front end of the wide groove 23 is open and communicates with the outside of the housing 1 (see fig. 11, where see the through opening 25 in fig. 11). The front end of the narrow groove 22 communicates with the rear end of the wide groove 23, and the wide groove 23 where the communication is made is formed with a rear end surface 26 (see fig. 11). The width of the outer hook 24 (see Y in fig. 10) is greater than the width of the narrow groove 22 (see X in fig. 9) and is smaller than the width of the wide groove 23 (see Z in fig. 9).

Corresponding to the position of the narrow groove 22, a radial projection 27 (see fig. 11) is provided in the wide groove 23, the front end of the radial projection 27 is provided with a locking end surface 28 (see fig. 11 and 15), and the rear to narrow groove 22 is provided with a transition bevel 29 or an arc surface (see fig. 11 and 17). The width of the radial projection 27 is equal to the width of the narrow groove 22 (see fig. 11).

The tail cap 4 is in sliding fit with the accommodating cavity 20 arranged at the tail of the housing 1 in the axial direction, the outer hook 24 is hooked on a rear end surface 26 of the wide groove 23 (see fig. 16) in a to-be-launched state, so that the tail cap 4 is located at a rear end limiting position relative to the accommodating cavity 20 of the housing 1, the outer hook 24 climbs along a transition inclined surface 29 or an arc surface until the outer hook crosses over the radial protrusion 27 (see fig. 17 and 18) when the tail cap 4 is pushed forwards, and the outer hook 24 is hooked on a locking end surface 28 of the radial protrusion 27 (see fig. 19) in a to-be-launched state, so that the tail cap 4 is located at a front end locking position relative to the accommodating cavity 20 of the housing 1.

In addition to the above locking structure, the blood collector of the embodiment of the present invention is further designed with the following locking structure between the tail cap 4 and the elastic arm 5:

the tail cover 4 is provided with an active locking part 14 (see fig. 7, 8 and 15), the active locking part 14 is provided with an acting end, a passive locking part 17 (see fig. 15) is arranged on the elastic arm 5 corresponding to the active locking part 14, the passive locking part 17 is provided with an acting end, the acting end of the active locking part 14 is provided with a locking hook 18 (see fig. 7, 8 and 15), and the acting end of the passive locking part 17 is provided with a locking surface 19 (see fig. 15).

In the state of waiting to be launched, taking the axial direction of the blood collector as reference, the axial projection distance from the action end (action point) of the active unlocking part 12 to the action end (action point) of the passive unlocking part 13 is smaller than the axial projection distance from the action end (action point) of the active locking part 14 to the action end (action point) of the passive locking part 17. The radial direction of the blood collector is taken as a reference, and the distance from the action end (action point) of the active locking part 14 to the radial center of the blood collector is greater than the distance from the action end (action point) of the passive locking part 17 to the radial center of the blood collector.

The initial assembly state and the using operation process of the embodiment of the invention are as follows:

1. initial assembled state

Referring to fig. 15, the stylet 2 and the twist cap 11 are integrally formed, the protective rod 16 on the stylet 2 and the twist cap 11 are positioned in the housing 1, and the twist part 15 on the twist cap 11 is positioned outside the front end of the housing 1. The boss provided between the torsion part 15 and the protection rod 16 abuts against the inner end surface (not marked but visible in fig. 15) of the pin outlet hole 9 at the front end of the housing 1. The front end of the spring 3 is pressed against the rear part of the stylet 2, the rear end of the spring 3 is pressed against the tail cap 4, and the outer hook 24 of the tail cap 4 is hooked on the rear end surface 26 of the sliding groove of the shell 1, so that the tail cap 4 is at the rear end limit position in the sliding direction relative to the accommodating cavity 20 of the shell 1. In this state, the hook 6 of the elastic arm 5 and the engaging surface 8 of the core 2 are in the unlocked state (separated from each other and not in contact engagement, see fig. 15). At this time, even if the tail cap 4 is pressed, the boss abuts against the inner end face of the needle outlet hole 9 at the front end of the shell 1, so that the blood sampler cannot generate the launching action, namely, under the condition that the twist cap 11 is not taken out, the tail cap 4 is pressed, and the needle core 2 cannot be triggered to launch. The purpose of the boss in the initial assembly state is therefore to prevent misfiring of the device.

2. State of waiting to be transmitted

Referring to fig. 16, before the blood sampling device is used, the twist cap 11 is twisted off, that is, the twist cap 11 is twisted by 90 °, the twist cap 11 and the needle core 2 are forced to be broken at the position of the contraction neck 7 (see fig. 5), the boss is aligned with the notch on the needle hole 9, and then the twist cap 11 is pulled out. At this time, the stylet 2 moves forward by 2mm under the action of the spring 3, the engaging surface 8 on the stylet 2 is blocked by the hook 6 on the elastic arm 5, so that the stylet 2 is locked by the hook 6 on the elastic arm 5, and enters a state to be shot.

3. State of tail cover pressing

Referring to fig. 17, in use, the needle outlet 9 of the blood collector head is aligned with the blood collection site of the human body, the tail cap 4 starts to be pressed (see the arrow in fig. 17), the tail cap 4 moves forward, on one hand, the outer hook 24 climbs onto the radial protrusion 27 along the transition inclined plane 29 (see fig. 17), on the other hand, the action end (corner of the bump) of the active unlocking part 12 on the tail cap 4 contacts with the action end (unlocking inclined plane 10) of the passive unlocking part 13 on the elastic arm 5 (see fig. 17).

The tail cap 4 is continuously pressed, the outer hook 24 on the tail cap 4 passes over the radial protrusion 27, the action end (corner of the bump) of the active unlocking part 12 on the tail cap 4 strikes the action end (unlocking inclined plane 10) of the passive unlocking part 13 on the elastic arm 5, the tail end of the elastic arm 5 is forced to expand laterally under the action of the unlocking inclined plane 10 (see a laterally expanded arrow in fig. 17), and the action end (action point) of the active locking part 14 and the action end (action point) of the passive locking part 17 are gradually close to each other.

4. Transmitting state

Referring to fig. 18, the tail cap 4 is continuously pressed, and after the hook 6 on the elastic arm 5 is separated from the locking critical point, the needle core 2 shoots and punctures under the action of the spring 3, so that blood collection is completed (see fig. 18).

5. Post-launch state

As shown in fig. 19, after the puncture is fired, the outer hook 24 hooks onto the locking end surface 28 of the radial protrusion 27 (see fig. 19) under the action of the spring 3, so that the tail cap 4 is in the front end locking position relative to the receiving cavity 20 of the housing 1. On the other hand, because the tail end of the flexible arm 5 is in a laterally opened state, the action ends of the active locking portions 14 on the tail cover 4 and the action ends of the passive locking portions 17 on the flexible arm 5 are mutually matched with the locking surfaces 19 through the locking hooks 18, so that the tail cover 4 and the flexible arm 5 are forced to be in a locking hook state, and the tail cover 4 cannot rebound (see fig. 19). In the locked state, the tail cap 4 is retracted from the rear of the blood collection set (see fig. 20).

Other embodiments and structural variations of the present invention are described below:

1. in the above embodiment, the tail cover 4 is designed with two elastic pieces 21 and two outer hooks 24 symmetrically arranged with each other, and two sets of narrow grooves 22 and wide grooves 23 are also designed corresponding to the elastic pieces 21 and the outer hooks 24. However, the present invention is not limited thereto, and one elastic piece 21 and one outer hook 24 may correspond to one set of narrow grooves 22 and wide grooves 23, or three elastic pieces 21 and three outer hooks 24 may correspond to three sets of narrow grooves 22 and wide grooves 23, which is a variation that can be understood and appreciated by those skilled in the art.

2. In the above embodiment, the active unlocking portion 12 and the active locking portion 14 are two solid portions on the tail cover 4, and the passive unlocking portion 13 and the passive locking portion 17 share one solid portion on the spring arm 5. However, the present invention is not limited to this, and may be modified in several ways:

(1) the active unlocking part 12 and the active latching part 14 share one physical portion on the tailgate 4, while the passive unlocking part 13 and the passive latching part 17 share one physical portion on the spring arm 5.

(2) The active unlocking part 12 and the active locking part 14 are two solid parts on the tail cover 4, while the passive unlocking part 13 and the passive locking part 17 are two solid parts on the spring arm 5.

(3) The active unlocking part 12 and the active latching part 14 share one physical portion on the tailgate 4, while the passive unlocking part 13 and the passive latching part 17 are two physical portions on the spring arm 5.

3. In the above embodiment, two elastic arms 5 are extended inward from the housing 1. However, the present invention is not limited to this, and the present invention may be modified in several ways other than the two elastic arms 5 in the above embodiments:

(1) the number of the elastic arms 5 arranged on the shell 1 is one, and the elastic arms 5 and the inner wall of the shell 1 form an elastic clamp for locking the needle core 2.

(2) The number of the elastic arms 5 arranged on the shell 1 is three, all the elastic arms 5 are evenly distributed in the circumferential direction of the cross section of the shell 1, and together form an elastic clamp for locking the needle core 2.

(3) The number of the elastic arms 5 arranged on the shell 1 is four, all the elastic arms 5 are evenly distributed in the circumferential direction of the cross section of the shell 1, and together form an elastic clamp for locking the needle core 2.

(4) The number of the elastic arms 5 arranged on the shell 1 is five, all the elastic arms 5 are evenly distributed in the circumferential direction of the cross section of the shell 1, and together form an elastic clamp for locking the needle core 2.

The number of resilient arms 5 is even greater, a variant which is easily understood by the person skilled in the art.

4. In the above embodiment, the elastic arm 5 is provided with the hook 6 for locking the stylet 2. The invention can be modified to have the hook 6 as an end face and the same technical effect can be achieved by using the end face to lock the needle core 2, as will be understood and appreciated by those skilled in the art.

5. In the above embodiment, in the state to be launched, with reference to the axial direction of the blood sampling device, the axial projection distance from the action end (action point) of the active unlocking part 12 to the action end (action point) of the passive unlocking part 13 is smaller than the axial projection distance from the action end (action point) of the active locking part 14 to the action end (action point) of the passive locking part 17. In addition, the projection distance from the action end (action point) of the active unlocking part 12 to the action end (action point) of the passive unlocking part 13 in the axial direction can be larger than the projection distance from the action end (action point) of the active locking part 14 to the action end (action point) of the passive locking part 17 in the axial direction. When the axial projection distance from the action end (action point) of the active unlocking part 12 to the action end (action point) of the passive unlocking part 13 is equal to the axial projection distance from the action end (action point) of the active locking part 14 to the action end (action point) of the passive locking part 17, the unlocking of the needle core 2 and the locking of the tail cover 4 are easy to interfere, so that the working of the blood sampler is unstable.

6. In the above embodiment, the acting end of the passive unlocking portion 13 is the unlocking slant 10. However, the present invention is not limited to this, and the unlocking slant 10 may be provided at the action end of the active unlocking portion 12, or may be provided at both the action end of the active unlocking portion 12 and the action end of the passive unlocking portion 13.

7. In the above embodiment, the active locking portion 14 has a locking hook 18 at its active end, and the passive locking portion 17 has a locking surface 19 at its active end. However, the present invention is not limited to this, and it is also possible to provide the active end of the active locking portion 14 with the locking surface 19 and the active end of the passive locking portion 17 with the locking hook 18.

8. In the above embodiments, the front portion of the needle core 2 is provided with the twist cap 11, so as to form a twist cap type rear pressing type disposable blood sampler structure, and after reading the present invention, those skilled in the art will know that the present invention is also applicable to a cap type rear pressing type disposable blood sampler structure, i.e. the front portion of the needle core 2 is provided with a cap, so as to form a cap type rear pressing type disposable blood sampler.

9. In the above embodiments, the hemostix head is not designed with an adjusting head structure capable of changing the puncture depth. In order to solve the problem of adjusting the puncture depth during blood sampling, an adjusting head structure capable of changing the puncture depth can be arranged at the head part of the shell 1. While the adjustment head structure for varying the penetration depth can be implemented using existing techniques, variations that are readily understood by those skilled in the art.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. An improved tail pressing type disposable safety hemostix, which comprises a shell (1), a stylet (2), a spring (3) and a tail cover (4);

the ejection cavity is formed in the shell (1), the needle core (2) is located in the ejection cavity, a locking structure is arranged between the needle core (2) and the shell (1), and in a to-be-ejected state, the spring (3) presses the needle core (2) and positions and locks the needle core (2) in the ejection cavity of the shell (1) through the locking structure;

the tail cover (4) is arranged at the tail part of the shell (1), and the tail cover (4) is used as a key of a tail part pressing type launching structure and is provided with an unlocking structure aiming at the locking structure;

the method is characterized in that: the tail part of the shell (1) is provided with an accommodating cavity (20), the tail cover (4) is arranged in the accommodating cavity (20), and the side part of the tail cover (4) is provided with an outer hook (24) which is turned over towards the outer side;

a narrow groove (22) and a wide groove (23) are arranged on the inner wall of the accommodating cavity (20) corresponding to the outer hook (24); the width of the narrow groove (22) is smaller than that of the wide groove (23); the narrow groove (22) is arranged at the axial rear part of the accommodating cavity (20), and the rear end of the narrow groove (22) is open and is communicated with the outside of the shell (1); the wide groove (23) is arranged at the axial front part of the accommodating cavity (20), and the front end of the wide groove (23) is open and is communicated with the outside of the shell (1); the front end of the narrow groove (22) is communicated with the rear end of the wide groove (23), and a rear end surface (26) is formed on the wide groove (23) at the communication position; the width of the outer hook (24) is larger than that of the narrow groove (22) and smaller than that of the wide groove (23), an elastic sheet (21) is arranged on the side of the tail cover (4), and the outer hook (24) is arranged at the tail end of the elastic sheet (21);

a radial protrusion (27) is arranged in the wide groove (23) corresponding to the position of the narrow groove (22), the width of the radial protrusion (27) is equal to that of the narrow groove (22), the front end of the radial protrusion (27) is provided with a locking end surface (28), and the rear part of the radial protrusion (27) is provided with a transition inclined surface (29) or an arc surface from the narrow groove (22);

the tail cover (4) is in sliding fit with an accommodating cavity (20) arranged at the tail of the shell (1) in the axial direction, the outer hook (24) is hooked on a rear end face (26) of the wide groove (23) in a to-be-launched state, the tail cover (4) is located at a rear end limiting position relative to the accommodating cavity (20) of the shell (1), the outer hook (24) climbs along a transition inclined plane (29) or an arc surface until the outer hook crosses a radial protrusion (27) when the tail cover (4) is pushed forwards, and the outer hook (24) is hooked on a locking end face (28) of the radial protrusion (27) in a to-be-launched state, so that the tail cover (4) is located at a front end locking position relative to the accommodating cavity (20) of the shell (1).

2. A lancing device according to claim 1, wherein: the hook angle of the outer hook (24) folded towards the outer side is smaller than or equal to 90 degrees.