CN114733007A

CN114733007A - Needle-shielded pre-filled syringe, assembly, method of installing assembly, and method of using assembly

Info

Publication number: CN114733007A
Application number: CN202210492290.0A
Authority: CN
Inventors: 不公告发明人
Original assignee: Shanghai Xinyaopaike Medical Technology Co ltd
Current assignee: Shanghai Xinyaopaike Medical Technology Co ltd
Priority date: 2022-05-07
Filing date: 2022-05-07
Publication date: 2022-07-12
Also published as: WO2023217041A1

Abstract

The invention belongs to the technical field of pre-filled and sealed syringes, and particularly relates to a needle head protection type pre-filled and sealed syringe, a component, a mounting method of the component and a using method of the component. The invention has the technical effect of conveniently and effectively covering the needle head after injection by the protective cover unit sleeved on the needle mounting part of the injection needle cylinder and the elastic hook unit for fixing the protective cover unit. The invention has the following advantages: firstly, the operation of opening injection and closing discarding can be realized only by sliding the protective cover along the injection needle cylinder when in use; secondly, an elastic hook is hooked with the side edge of the sliding opening and used for fixing the protective cover; thirdly, the elastic plate is provided with a stop surface which is clamped with the elastic hook together and can fix the protective cover in an open state; fourthly, the protective cover can be ejected to the needle head to be closed by pinching the elastic plate, and the operation can be carried out by one hand; fifthly, when the needle protective sleeve coats the injection needle, the elastic plate and the elastic hook are disengaged, and the protective cover can be conveniently opened to directly inject.

Description

Needle-shielded pre-filled syringe, assembly, method of installing assembly, and method of using assembly

Technical Field

The invention belongs to the technical field of pre-filled and sealed syringes, and particularly relates to a needle head protection type pre-filled and sealed syringe, a component, a mounting method of the component and a using method of the component.

Background

A syringe is a common medical device, which mainly uses a needle to extract or inject gas or liquid, and the process is called injection, and the syringe consists of a syringe barrel with a small hole at the front end and a matched piston core rod and is used for injecting a small amount of liquid or gas into an area which cannot be accessed by other methods, and the liquid or gas is extruded when the core rod is pushed in. However, the disposable syringe has poor stability, the medicine needs to be filled before use, and the air needs to be extruded after the medicine is filled, so that the medicine is filled in advance, and the pre-filled syringe which is directly injected after being opened is developed and popularized for use.

However, the existing pre-filling and sealing syringe is often discarded at will after being used, the needle is exposed outside, the syringe is very dangerous, and the nurse often reloads the pulled needle protective sleeve back for solving the problem that the needle is exposed after the syringe is discarded. However, this has many disadvantages, such as the needle protection cover is customized for the needle, the opening is small, and it is difficult to insert the needle back again after pulling out, and the needle is easy to prick the hand of the nurse in the process of re-installing the needle back, which causes infection to the medical staff.

Therefore, in summary, there is an urgent need for a pre-filled and sealed syringe which can effectively cover the needle after injection and prevent the needle from hurting people.

Disclosure of Invention

The invention aims to provide a needle head protection type pre-filling and sealing injector, a component mounting method and a component using method.

The technical scheme adopted by the invention for solving the problems is as follows: a needle head protection type pre-filling and sealing injector comprises an injection needle cylinder, a needle mounting piece, an injection needle and a needle protection sleeve; wherein:

the needle mounting piece is arranged at the far end of the injection needle cylinder, the needle mounting piece is provided with a through hole and is communicated with the interior of the injection needle cylinder, the injection needle is mounted on the needle mounting piece in a mode of being inserted into the through hole, the needle protective sleeve is sleeved on the needle mounting piece and completely covers the injection needle, and the injection needle cylinder, the needle mounting piece, the injection needle and the needle protective sleeve have a common axis;

still include the protection casing unit, the protection casing unit includes:

a protective cover with a sliding opening is arranged on the injection needle to shield the injection needle;

still include elasticity and collude the unit, elasticity colludes the unit and is in including setting up stretch into the elasticity of slip mouth colludes.

The protection casing unit still includes the elastic plate, the elastic plate cantilever sets up in the sliding port, the near-end has along the radial adduction trend of protection casing.

The near end of the elastic plate is provided with a near end stop surface for jacking the elastic hook when the protective cover is closed, so that the protective cover is locked.

The inner side of the elastic plate is provided with a far-end stop surface used for jacking the elastic hook when the protective cover is opened, so that the protective cover is locked.

The elastic hook comprises a radial plate, and a stop surface for closing is arranged on the far end side of the radial plate and used for jacking the near-end stop surface.

The elastic hook further comprises an axial plate, wherein an opening stop surface is arranged on the near-end side of the axial plate and used for jacking the far-end stop surface.

The axial plate near-end is followed the protection casing radially outwards expands, jack-up when the distal end stops the position, through following the protection casing radially inwards presses to move or outwards pulls the elastic plate, make the opening of axial plate with the position face with the distal end stops the position and breaks away from the jack-up state.

The needle protection sleeve is sleeved on the needle mounting piece, and the needle protection sleeve jacks the raised block outwards in the radial direction along the protection cover when the needle mounting piece is mounted, so that the jacking state of the proximal end stop surface on the elastic plate and the stop surface for closing on the radial plate is released.

The side of the near end of the protruding block is provided with an opening guide surface, and when the protective cover slides to the near end, the protective cover is used for jacking the axial plate of the elastic hook, so that the elastic hook passes over the protruding block.

The protruding block further comprises a closing guide surface, and when the protective cover slides to the far end, the protective cover is used for jacking the axial plate of the elastic hook, so that the elastic hook passes over the protruding block.

The protective cover unit further comprises an expansion groove arranged at the proximal end of the protective cover and used for expanding the proximal end of the protective cover.

The protection cover unit further comprises a guide inclined plane arranged at the near end of the protection cover and used for jacking up the axial plate of the elastic hook.

An assembly of the needle-protected pre-filled syringe includes a push rod and a piston; wherein:

the push rod is arranged on the piston;

the piston is arranged in the injection syringe and is used for pushing the liquid medicine out through the injection needle when the push rod is pushed towards the far end direction.

A method of installing an assembly of a needle-shielded pre-filled syringe, comprising the steps of:

s1, axially installing the needle protection sleeve into the protection cover;

s2, sleeving the protective cover with the needle protective sleeve on the needle mounting piece along the axial direction;

s3, pushing the piston into the injection needle cylinder;

s4, arranging the push rod on the piston.

A method of using an assembly of a needle-shielded pre-filled syringe, comprising the steps of:

s1, axially moving the protective cover along the proximal direction of the injection needle cylinder until one side of the back face of the elastic hook supports against the far-end side face of the sliding opening, so that the needle protective sleeve is exposed;

s2, opening the needle protection sleeve to expose the injection needle;

s3, performing injection operation;

and S4, after the injection operation is finished, axially moving the protective cover along the far end direction of the injection needle cylinder until one side of the elastic hook hooks the side surface of the near end of the sliding port, so that the injection needle is completely covered.

The invention has the following advantages:

firstly, the mounting is convenient, the structure is simple, and the operation of opening the injection and closing the discard can be realized only by sliding the protective cover along the injection needle cylinder when in use;

secondly, the elastic hook is hooked with the side edge of the sliding opening and used for fixing the protective cover, the fixing effect is good, and the protective cover is not easy to be separated from a clamping state;

thirdly, the elastic plate is arranged, the stop surface is arranged on the elastic plate and is clamped with the elastic hook, so that the protective cover can be fixed to be in an open state, and the injection is convenient for nurses to carry out injection;

fourthly, after the nurse finishes the injection, the stop surface and the elastic hook can be disengaged by pinching the elastic plate by two fingers, so that the protective cover is ejected to the needle head to realize the closing, and the single-hand operation can be realized for the nurse with short fingers by pinching the closing mode;

fifthly, when the needle protective cover covers the injection needle, the elastic plate and the elastic hook are released from the clamping state, and a nurse can conveniently open the protective cover to directly inject.

Drawings

Fig. 1 is a structural schematic diagram of the needle protection cover covering the injection needle, and the protection cover unit and the elastic hook unit are arranged on the injection needle cylinder.

Fig. 2 is a schematic structural view of the needle protection cover covering the injection needle and the injection needle cylinder is provided with the elastic hook unit.

Fig. 3 is a schematic structural view of the syringe having the elastic hook unit mounted thereon according to the present invention.

Fig. 4 is a schematic structural view of the syringe of the present invention having a protective cover unit and an elastic hook unit mounted thereon.

Fig. 5 is an exploded view of a pre-filled syringe according to the present invention.

Fig. 6 is a schematic cross-sectional view taken along line a-a in fig. 4.

Fig. 7 is an enlarged structural view of the elastic hook of fig. 6.

Fig. 8 is an enlarged view of the injection needle of fig. 6.

FIG. 9 is a schematic view of the elastic hook of the present invention.

FIG. 10 is a schematic view of another side view of the elastic hook of the present invention.

Fig. 11 is a schematic structural view of the shield unit according to the present invention.

Fig. 12 is a schematic structural view of the other side of the protective cover unit according to the present invention.

Fig. 13 is a schematic structural view of the elastic plate of the present invention.

In the drawings, the reference numerals denote the following components: the needle protection device comprises a protection cover unit 1, an elastic hook unit 2, a syringe 11, a needle mounting piece 12, an injection needle 13, a needle protection sleeve 14, a protection cover 101, a sliding opening 102, an elastic plate 103, an expansion groove 104, a guide inclined plane 105, an elastic hook 202, a proximal end stop surface 103a, a distal end stop surface 103b, a protrusion block 103c, an opening guide surface 103d, a closing guide surface 103e, a stop groove 201a, a radial plate 202a, an axial plate 202b, a closing stop surface 202c, an opening stop surface 202d and a through hole 12 a.

Detailed Description

Definition of

1. A far end: refers to the end far away from the medicine injection opening of the injection syringe.

2. Proximal end: refers to the end towards the medicine injection opening of the injection syringe.

3. Axis: refers to an object having a circular cross-section through the vertical line of the center of the circle.

4. Opening: refers to a state in which the syringe needle or the syringe needle and the protective sheath are exposed.

5. Closing: the finger is covered with the syringe needle or the syringe needle and the protective sleeve.

6. Setting: refers to any means for arranging and bonding two components together by bonding, snapping, welding, screwing, placing, etc.

7. Jacking: the first finger component exerts a force on the second component, so that the second component moves or deforms towards the direction opposite to the position of the first component.

The following description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Example (b): as shown in fig. 1-13, a needle-protected prefilled syringe includes a syringe barrel 11, a needle mounting member 12, a needle 13 and a needle shield 14; wherein:

the needle mounting member 12 is disposed at the distal end of the syringe 11, the needle mounting member 12 has a through hole 12a communicating with the inside of the syringe 11, the injection needle 13 is mounted on the needle mounting member 12 in such a manner as to be inserted into the through hole 12a, the needle protection cover 14 is fitted over the needle mounting member 12 and completely covers the injection needle 13, and the syringe 11, the needle mounting member 12, the injection needle 13, and the needle protection cover 14 have a common axis;

still include protection casing unit 1, protection casing unit 1 includes:

a shield 101 provided with a sliding port 102 to shield the injection needle 13;

the elastic hook unit 2 is further included, and the elastic hook unit 2 includes an elastic hook 202 which is arranged on the sliding opening 102.

In this embodiment, the injection syringe 11, the needle mounting member 12, the injection needle 13 and the needle protecting sleeve 14 are all necessary components of an injection syringe in the prior art to realize the functions of filling and injecting a medicine, and the elastic hook unit 2 and the protecting cover unit 1 are installed in the following manner:

1. the elastic hook unit 2 is installed on the needle installation member 12, and the hook bending direction faces to the proximal end of the injection needle cylinder 11;

2. when the protective cover 101 of the protective cover unit 1 is mounted on the needle mounting member 12 in a sleeved manner, the protective cover is mounted on the elastic hook 202 of the elastic hook unit 2 in a sleeved manner through deformation, and after the elastic hook 202 is crossed, the sliding port 102 is sleeved on the elastic hook 202.

The elastic hook 202 slides into the sliding opening 102 in the sleeving process and hooks the side surface of the near end side of the sliding opening 102, so that the blocking effect of the protective cover 101 sliding towards the far end direction is realized.

After the installation is finished, the components are handed over to a downstream manufacturer to fill the medicine, the medicine is filled from a medicine injection port of the injection needle cylinder 11, and then a push rod and an injection piston are installed on the injection needle cylinder 11 through the medicine injection port to complete the pre-encapsulation of the injector.

Furthermore, it should be noted that the needle protection sheath 14 is standardized in shape using existing pre-potted needle sheath materials, rather than a non-standard shaped cap, which is advantageous in that:

1. the use habit of the user is not changed;

2. the chemical compatibility of the rubber protective cap does not need to be evaluated again, so that the project development period and the product registration period are greatly reduced;

3. enhancing the customer confidence.

The using method of the pre-filling and sealing syringe comprises the following steps:

1. axially moving the protective cover 101 along the proximal direction of the syringe 11 until the back side of the hook of the elastic hook 202 abuts against the distal side of the sliding port 102, thereby exposing the needle protecting sheath 14;

2. opening the needle protection 14 to expose the injection needle 13;

3. performing injection operation;

4. after the injection operation is completed, the protective cover 101 is axially moved along the distal direction of the injection needle cylinder 11 until one side of the hook of the elastic hook 202 hooks the proximal side surface of the sliding port 102, so as to completely cover the injection needle 13.

The mounting method of the pre-filling and sealing syringe comprises the following steps:

s1, the needle protection sleeve 14 is axially installed in the protection cover 101;

s2, the protective cover 101 with the needle protective sleeve 14 is sleeved on the needle mounting piece 12 along the axial direction;

s3, pushing the piston into the injection needle cylinder 11;

s4, arranging the push rod on the piston.

In this embodiment, the needle protection sleeve 14 is first installed in the protection cover 101, which is beneficial to the steps of automatic assembly of syringe components, and can simplify the flow of production line, reduce the cost of component installation process, and further improve market competitiveness.

It should be noted that the position of the elastic hook 202 may be a part of the syringe 11, a part of the needle mounting member 12, or a part between the syringe 11 and the needle mounting member 12.

In addition, the light inspection can be performed on the injector when the injector leaves the factory, the light inspection refers to that whether the injector filling and plugging are qualified or not is checked through the manual observation mode of the needle cylinder, and most of integrated protective covers in the market influence the process, for example, the Chinese utility model with the bulletin number of CN214911888U and the bulletin date of 2021-11-30 discloses an injector needle head protective device and a safety injector thereof, which comprises a protective outer sleeve, a mounting inner sleeve and a spring, wherein the inner sleeve and the outer sleeve are sleeved to block the view field inside the needle cylinder, so that the light inspection process is influenced, and in the embodiment, the protective cover unit 2 only covers the needle mounting tube 12 under the condition that the needle cylinder is not used, and the partial far-end side end head of the needle cylinder 11 does not influence the light inspection process.

However, the protection cover 101 needs to achieve a fixing effect after being closed, and further, the protection cover unit 1 further includes an elastic plate 103, the elastic plate 103 is cantilevered in the sliding opening 102, and the proximal end has a tendency to be retracted along the radial direction of the protection cover 101.

The function and implementation of the elastic plate 103 are as follows:

1. when the protective cover 101 is opened, the elastic hook 202 jacks up the elastic plate 103 radially outwards along the protective cover 101, so that elastic potential energy is accumulated in the elastic plate 103, and when the protective cover 101 is released, the elastic potential energy of the elastic plate 103 is released to drive the protective cover 101 to be ejected axially along the distal direction of the injection needle cylinder 11, so that the automatic closing effect is realized;

2. when the protection cover 101 is closed, the hook back of the elastic hook 202 is jacked up by the end face of the proximal end of the elastic plate 103, so that when the protection cover 101 moves towards the proximal end, the protection cover is propped against the hook back of the elastic hook 202, and when the protection cover moves towards the distal end, the protection cover is hooked on the inner side face of the sliding opening 102 by the elastic hook 202, and a locking effect is achieved.

In order to make the elastic plate 103 lock the elastic hook 202 more firmly, further, the proximal end of the elastic plate 103 has a proximal end stop surface 103a for jacking up the elastic hook 202 when the protection cover 101 is closed, thereby locking the protection cover 101.

When the protection cover 101 is opened, a nurse is still required to pull the protection cover by hand, which is inconvenient for the injection process, and further, a distal end stop surface 103b is provided on the inner side of the elastic plate 103 for jacking up the elastic hook 202 when the protection cover 101 is opened, thereby locking the protection cover 101.

The elastic hook 202 jacks up the elastic plate 103 along the radial direction of the protective cover 101, according to the interaction principle of force, the elastic plate 103 also jacks up the elastic hook 202 along the radial direction of the protective cover 101, so that the elastic hook 202 contracts, when the elastic hook 202 passes over the far-end stop surface 103b, the elastic hook 202 rebounds and recovers to the original shape, and then hooks the far-end stop surface 103b, so that the protective cover 101 cannot slide towards the far-end direction even under the pushing action of the elastic plate 103.

In addition, when the elastic hook 202 hooks the distal stop surface 103b, a "snap" sound is generated to remind the nurse that the protection cover 101 is locked and the injection is available.

In order to match the proximal end stop surface 103a, further, the elastic hook 202 includes a radial plate 202a, and a stop surface 202c for closing is provided at a distal end side of the radial plate 202a for jacking up the proximal end stop surface 103 a.

When the closure stop surface 202c lifts against the proximal stop surface 103a, a "snap" sound is also produced alerting the nurse that the shield 101 is locked and may be discarded.

Meanwhile, in order to match the distal end stop surface 103b, the elastic hook 202 further comprises an axial plate 202b, and an opening stop surface 202d is arranged on the proximal end side of the axial plate 202b and used for jacking up the distal end stop surface 103 b.

After the injection, the protection cover 101 needs to be closed, and in order to make the closing process more smooth, further, the proximal end of the axial plate 202b expands radially outward along the protection cover 101, and when the distal end stop surface 103b is jacked up, the elastic plate 103 is pressed or pulled radially inward along the protection cover 101, so that the open stop surface 202d of the axial plate 202b and the distal end stop surface 103b are separated from the jacked state.

When the elastic plate 103 is pulled radially outward, the distal end stop surface 103b is moved radially outward, and is thereby disengaged from the open stop surface 202d of the axial plate 202 b.

The principle of pressing the elastic plate 103 radially inward to disengage the opening stop surface 202d of the axial plate 202b from the distal stop surface 103b in the above-described process is as follows:

when the elastic plate 103 is expanded under a force, the proximal end is expanded to a greater extent than the distal end, the inner side surface of the elastic plate 103 inclines outwards from the distal end to the proximal end, the axial plate 202b inclines in a manner consistent with the inner side surface of the elastic plate 103, so that when the elastic plate 103 is pressed radially inwards along the shield 101, because the length of the elastic plate 103 is longer, the length of the axial plate 202b is shorter, and when the same distance is pressed, the axial plate 202b contracts more significantly, so that when the distance is pressed to a certain extent, the opening stop surface 202d of the axial plate 202b is disengaged from the distal stop surface 103b, and the shield 101 is closed under the pushing action of the elastic plate 103.

The advantage of this kind of design lies in, the nurse finishes injecting the back, as long as use two fingers of thumb and forefinger, holds between the fingers gently, just can realize closing protection casing 101, than the mode that promotes to close, holds between the fingers the mode of closing like this, need not nurse's palm application of force, also need not to remove thumb and forefinger and keep away from the palm, to the nurse that the finger is shorter little, also can realize one-hand operation, is a design promptly for ingenious. Meanwhile, the inward pinching mode is more convenient than outward poking, the angle does not need to be found, the fingernail does not need to be embedded into the sliding opening 102, and even the operation can be realized without visual observation of a nurse.

In order to make it unnecessary to lift the elastic plate 103 when the protective cover 101 is opened, a raised piece 103c is further provided on an inner side surface of a proximal end side of the elastic plate 103, and when the needle protective cover 14 is fitted to the needle mount 12, the raised piece 103c is raised radially outward along the protective cover 101, so that the raised state is released between the proximal end stop surface 103a on the elastic plate 103 and the stop surface 202c for closing on the radial plate 202 a.

In order that the protrusion 103c does not interfere with the opening process of the shield 101, further, the proximal side of the protrusion 103c has an opening guide surface 103d for pushing up the axial plate 202b of the elastic hook 202 when the shield 101 is slid proximally, so that the elastic hook 202 passes over the protrusion 103 c.

In order that the projection 103c does not interfere with the closing process of the protection cover 101, further, the projection 103c further includes a closing guide surface 103e for lifting up the axial plate 202b of the elastic hook 202 when the protection cover 101 is slid distally, so that the elastic hook 202 passes over the projection 103 c.

The protection casing 101 cup joints to be installed when the needle installed part 12 is gone up, cup joints simultaneously through the deformation effect and is in on the elasticity colludes 202, but the protection casing 101 has certain thickness, is difficult to the deformation, and the installation is more laboursome, and is further, protection casing unit 1 still including setting up the groove 104 is used in the expansion of protection casing 101 near-end, be used for the near-end expansion of protection casing 101.

After the expansion groove 104 is provided, when the protection cover 101 is deformed, the protection cover 101 can be provided with a moving space by expanding the expansion groove 104, so that the protection cover can more easily pass over the elastic hook 202.

In order to make the process of the protective cover 101 passing over the elastic hook 202 smoother, further, the protective cover unit 1 further comprises a guide slope 105 disposed at the proximal end of the protective cover 101 for jacking up the axial plate 202b of the elastic hook 202.

The inclined angle of the guiding slope 105 is similar to that of the axial plate 202b, and when the axial plate 202b is jacked up, the proximal end of the protection cover 101 is driven to expand so as to pass over the elastic hook 202.

the push rod is arranged on the piston;

the plunger is installed in the syringe 11 and pushes the plunger in a distal direction to push out the medical solution through the needle 13.

In the present embodiment, it is essential that the plunger and the plunger are detachably connected together, so that the plunger is easily installed in the syringe 11 in a mechanical and automatic manner, and the plunger and plunger assembling method and the medicine filling method are as follows:

s1, syringe placement: grabbing the injector body, and enabling the injection needle cylinder 11 to be in a state of being vertical to a horizontal plane, wherein the opening of the near end is upward;

in the present embodiment, the "grabbing" step generally employs a mechanical arm designed by a program, and the core of the program is to keep the syringe 11 in a vertical state when reaching the position to be filled, so that the liquid level after filling the medicine is axially vertical to the syringe 11, so that no air or less air is left after packaging but the injection process is not affected.

S2, filling medicine: filling the syringe 11 with a specified medicine;

in this embodiment, the "designated drug" refers to a drug that is self-filled according to the customer's requirement, for example, a manufacturer that fills a new coronavirus vaccine, and the designated drug is an inactivated new coronavirus.

S3, sleeve plugging: inserting the sleeve with the piston into the injection needle cylinder 11, wherein a gap is reserved between the outer annular surface of the sleeve and the inner annular surface of the injection needle cylinder 11, and then pushing the piston into the injection needle cylinder 11 along the inner annular surface of the sleeve by using a sleeve push rod;

in this embodiment, the plunger is a device for pushing medication, which is commonly used in injectors, and is typically made of medical grade rubber, and is compressed in the sleeve and expands to fit the inside of the syringe barrel 11 after leaving the sleeve.

Furthermore, the sleeve is an elongated steel tube and is inserted into the syringe barrel 11 from the crimp and the plunger is moved by means of a sleeve pusher mounted in the sleeve to a predetermined position, which is after the plunger has left the sleeve, just above the surface of the medical fluid, leaving no or little air between them and not affecting the injection process.

S4, installing a push rod: the push rod is inserted into the syringe 11 and mounted on the piston, completing the potting process.

In this embodiment, the piston has a mounting groove for mounting the push rod at the proximal end, and the push rod is rotatably inserted into the mounting groove by using a mechanical arm.

S5, performing light inspection and labeling on the filled injector, and finally completing packaging.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various modifications can be made within the knowledge of those skilled in the art without departing from the gist of the present invention. These are non-inventive modifications, which are intended to be protected by patent laws within the scope of the claims appended hereto.

Claims

1. A needle-protected pre-filled syringe comprises a syringe barrel (11), a needle mounting piece (12), a syringe needle (13) and a needle protection sleeve (14); wherein:

the needle mounting piece (12) is arranged at the far end of the injection needle cylinder (11), the needle mounting piece (12) is provided with a through hole (12 a) and is communicated with the inside of the injection needle cylinder (11), the injection needle (13) is mounted on the needle mounting piece (12) in a mode of being inserted into the through hole (12 a), the needle protection sleeve (14) is sleeved on the needle mounting piece (12) and completely covers the injection needle (13), and the injection needle cylinder (11), the needle mounting piece (12), the injection needle (13) and the needle protection sleeve (14) have a common axis;

characterized in that, still include protection casing unit (1), protection casing unit (1) includes:

a protective cover (101) provided with a sliding opening (102) to shield the injection needle (13);

the sliding device is characterized by further comprising an elastic hook unit (2), wherein the elastic hook unit (2) comprises an elastic hook (202) extending into the sliding opening (102).

2. A needle-shielded pre-filled and sealed syringe according to claim 1, characterized in that said shield unit (1) further comprises a resilient plate (103), said resilient plate (103) being cantilevered inside said sliding port (102), the proximal end having a tendency to retract radially inwards of said shield (101).

3. A needle-protected pre-filled and sealed syringe according to claim 2, characterised in that said elastic plate (103) has a proximal stop surface (103 a) at its proximal end for lifting said elastic hook (202) when said protection shield (101) is closed, so as to lock said protection shield (101).

4. A needle-protected pre-filled and sealed syringe according to claim 3, characterized in that the elastic plate (103) is provided inside with a distal stop surface (103 b) for lifting the elastic hook (202) when the shield (101) is opened, thereby locking the shield (101).

5. A needle-protected pre-filled and sealed syringe according to claim 4, characterised in that the elastic hooks (202) comprise radial plates (202 a), the distal sides of the radial plates (202 a) being provided with a stop surface (202 c) for closing for jacking up the proximal stop surface (103 a).

6. A needle-protected pre-filled and sealed syringe according to claim 5, characterized in that the elastic hook (202) further comprises an axial plate (202 b), and the proximal side of the axial plate (202 b) is provided with an opening stop surface (202 d) for jacking up the distal stop surface (103 b).

7. A needle-shielded pre-filled and sealed syringe according to claim 6, characterized in that the proximal end of the axial plate (202 b) is expanded radially outwards along the shield (101) and the opening stop surface (202 d) of the axial plate (202 b) is lifted off from the distal stop surface (103 b) by pressing or pulling the resilient plate (103) radially inwards along the shield (101) when lifting the distal stop surface (103 b).

8. A needle-protected prefilled syringe according to claim 5, wherein said resilient plate (103) is provided with a protrusion (103 c) on the inner side of the proximal side, and said needle shield (14) when fitted over said needle mount (12) radially pushes said protrusion (103 c) outwards along said shield (101) so that said proximal stop surface (103 a) on said resilient plate (103) is released from said pushing up state with said closing stop surface (202 c) on said radial plate (202 a).

9. A needle-protected pre-filled and sealed syringe according to claim 8, characterised in that the proximal side of the boss (103 c) has an opening guide surface (103 d) for lifting up the axial plate (202 b) of the elastic hook (202) when the protection shield (101) is slid proximally, so that the elastic hook (202) passes over the boss (103 c).

10. A needle-protected pre-filled and sealed syringe according to claim 9, characterised in that said protruding block (103 c) further comprises a closing guide surface (103 e) for jacking up the axial plate (202 b) of said elastic hook (202) when said protection shield (101) is slid distally, so that said elastic hook (202) passes over said protruding block (103 c).

11. A needle-shielded pre-filled and sealed syringe according to claim 1, characterized in that the shield unit (1) further comprises an expansion slot (104) provided at the proximal end of the shield (101) for proximal expansion of the shield (101).

12. A needle-protected pre-filled and sealed syringe according to claim 6, characterized in that said shield unit (1) further comprises a guiding bevel (105) arranged at the proximal end of said shield (101) for jacking up the axial plate (202 b) of said elastic hook (202).

13. An assembly comprising the needle-protected prefilled syringe of any one of claims 1 to 12, comprising a plunger and a piston; wherein:

the push rod is arranged on the piston;

the piston is arranged in the injection syringe (11) and is used for pushing out the liquid medicine through the injection needle (13) when pushing the push rod towards the far end direction.

14. A method of mounting the assembly of a needle-shielded pre-filled syringe as defined in claim 13, comprising the steps of:

s1, axially installing the needle protection sleeve (14) into the protection cover (101);

s2, sleeving the protective cover (101) with the needle protective sleeve (14) on the needle mounting piece (12) along the axial direction;

s3, pushing the piston into the injection needle cylinder (11);

s4, arranging the push rod on the piston.

15. A method of using the needle-shielded pre-filled syringe assembly of claim 13, comprising the steps of:

s1, axially moving the protective cover (101) along the proximal direction of the injection syringe (11) until one side of the hook back of the elastic hook (202) abuts against the far-end side face of the sliding opening (102), so that the needle protective sleeve (14) is exposed;

s2, opening the needle protection sleeve (14) to expose the injection needle (13);

s3, performing injection operation;

s4, after the injection operation is finished, the protective cover (101) is axially moved along the far end direction of the injection needle cylinder (11) until one side of the hook of the elastic hook (202) hooks the side surface of the near end of the sliding opening (102), so that the injection needle (13) is completely covered.