CN113384776A

CN113384776A - Medicine injection device for multiple injections

Info

Publication number: CN113384776A
Application number: CN202110561355.8A
Authority: CN
Inventors: 侯士双; 胡高扬; 陈常娇
Original assignee: Ningbo Ruiai Product Design Co ltd
Current assignee: Ningbo Ruiai Product Design Co ltd
Priority date: 2021-05-22
Filing date: 2021-05-22
Publication date: 2021-09-14
Anticipated expiration: 2041-05-22
Also published as: CN113384776B

Abstract

The application relates to a medicine injection device for multiple injections, which comprises a shell, a plunger rod, a driving spring and a locking sleeve, wherein the plunger rod is axially installed on the shell in a sliding manner; the outer side of the plunger rod is provided with a plunger convex part; the drive spring drives the plunger rod to always have a tendency to move towards the injection direction; the locking sleeve is provided with a locking stepped structure for the abutment of the plunger convex part to restrict the plunger rod to move towards the injection direction; after the locking sleeve rotates for a specified angle towards the unlocking direction, the plunger convex part is separated from the locking stepped structure and forms an injection stroke with the next-stage stepped surface of the locking stepped structure, and under the action of the driving spring, the plunger rod moves towards the injection direction until the plunger convex part is abutted against the next-stage stepped surface of the locking stepped structure. The present application has the effect of less pressure fluctuations being exerted on the piston of the cartridge bottle during injection.

Description

Medicine injection device for multiple injections

Technical Field

The present application relates to the field of syringes, and more particularly, to a multiple injection medication injection device.

Background

A multi-injection medicine injection device is a medicine injection device capable of injecting a liquid medicine in a medicine tube into a patient in several divided injections. Since the multi-injection medicine injection device can be used several times, the requirements of patients are more satisfied. In the conventional medicine injection device for multiple injections, when the medicine is injected, the pushing force applied to the tail cap by the user is transmitted to the piston of the cartridge bottle through the built-in linkage structure, so that the medicine liquid in the cartridge bottle is pressed out.

In view of the above-mentioned related arts, the inventor believes that the above-mentioned multiple injection medicine injection device requires a person to continuously apply force to push the cartridge bottle piston to move during injection, and the speed at which the cartridge bottle piston is pushed is not stable due to the unstable pressure applied to the cartridge bottle piston.

Disclosure of Invention

In order to enable the pressure fluctuation applied to the piston of the cassette bottle when the medicine injection device for multiple injections is used for injection to be small and the medicine is injected at a uniform speed, the application provides the medicine injection device for multiple injections.

The application provides a medicine injection device of many injections adopts following technical scheme:

a medicine injection device for multiple injections comprises a shell, a plunger rod, a driving spring and a locking sleeve, wherein the plunger rod is axially slidably arranged on the shell, the driving spring is arranged in the shell, and the locking sleeve is circumferentially and rotatably arranged in the shell and sleeved on the outer side of the plunger rod; a plunger convex part is arranged on the outer side of the plunger rod; the drive spring drives the plunger rod to always have a tendency to move towards the injection direction; the locking sleeve is provided with a locking stepped structure for the plunger convex part to abut against so as to restrain the plunger rod from moving towards the injection direction;

wherein a circumferential direction of an inclination direction of the locking stepped structure in a direction from the front end to the rear end is defined as an unlocking direction;

after locking sleeve turned the appointed angle towards the unblock direction, the plunger convex part with locking ladder structure throw off and with form the injection stroke between the next level ladder face of locking ladder structure under drive spring's effect, the plunger rod removes until to the injection direction the plunger convex part with locking ladder structure's next level ladder face butt.

By adopting the technical scheme, the implementation principle of the medicine injection device for multiple injections is that the driving spring always drives the plunger rod to have a trend of always moving towards the injection direction, and the injection direction refers to the direction in which the plunger rod presses the piston of the cassette bottle to enable the liquid medicine in the cassette bottle to be injected into the body of a patient; when the locking sleeve is rotated towards the unlocking direction, the restraint of the locking stepped structure in the locking sleeve on the plunger convex part is eliminated, so that the plunger rod moves towards the injection direction for a distance which can be controlled by the distance between two adjacent stepped surfaces in the locking stepped structure, and different injection dosage requirements can be set in the medicine injection device for injecting a plurality of times through the setting.

The medicine injection device for multiple injections does not transmit the force of a user to the piston of the cassette bottle through the built-in transmission mechanism, but presses the plunger rod through the driving spring, so that the driving force of the plunger rod moving towards the injection direction is kept constant, the speed of the medicine injection device for multiple injections is kept constant when liquid medicine is input into a patient, the amount of the liquid medicine input into the patient in unit time is stable, and the experience feeling of the patient when the liquid medicine is injected is improved.

Optionally, the tail cover assembly is further included; the tail cap assembly is rotatably mounted on the housing, the components in the tail cap assembly being configured to circumferentially interlock with one another; the tail cover assembly comprises a key and a tail end spring, the key is mounted on the tail cover assembly and is provided with a first station and a second station in the axial direction, and the second station is positioned behind the first station; the key is circumferentially limited when moving from the second station to the first station; the locking sleeve is provided with a guide surface arranged towards the tail end direction; the key is provided with a driving surface which is used for being abutted with the guide surface to drive the locking sleeve to rotate towards the unlocking direction.

Through adopting above-mentioned technical scheme, when the medicine injection device that carries out many times injection injects, through the button in the tail-hood subassembly of pushing down, press the button to first station from the second station for locking sleeve rotates the appointed angle to the unblock direction under the cooperation of spigot surface and drive face, the medicine injection device of above-mentioned many times injection removes the circumferential direction of drive locking sleeve through the axial displacement of button, makes the injection operation of the medicine injection device of many times injection comparatively convenient.

Optionally, the locking sleeve is further provided with a locking hook portion, and the key is provided with a hook groove; the hook groove is configured to be inserted by the locking hook when the key is in the first station, restricting movement of the key in the axial direction.

Through adopting above-mentioned technical scheme, when the button is pressed and is removed to the in-process of first station from the second station, the locking sleeve can rotate appointed angle towards the unblock direction to make locking hook portion insert the hook inslot of button, thereby realize locking the axial of button, make the button can not resume to second station department under the effect of tail end spring. When the patient needs to use the medicine injection device of many times injection next time to inject, need rotate tail-hood subassembly to make locking hook portion deviate from the hook inslot of button, the button is replied to the second station from first station, makes to press the button once more and orders about locking sleeve circumferential direction. The setting reduces the probability of the waste of the liquid medicine caused by the fact that the patient mistakenly presses the key after one injection is finished.

Optionally, the key has a driving lug plate extending towards the locking sleeve, and the driving surface and the hook groove are both disposed on the driving lug plate.

Through adopting above-mentioned technical scheme, all set up drive face and hook groove on the drive flange for the compact structure of button.

Optionally, the tail cap assembly comprises a limiting pipe sleeve sleeved on the outer side of the plunger rod, the limiting pipe sleeve is provided with a limiting stepped structure for abutting the plunger convex part, the limiting stepped structure is located on one side of the plunger convex part, which faces away from the locking stepped convex part, and the limiting stepped structure is configured such that when the plunger convex part abuts on the limiting stepped structure, the driving surface is opposite to the guide surface.

By adopting the technical scheme, after one-time injection is completed, the key is positioned at the first station and is locked by the locking hook part of the locking sleeve, so that the tail cover assembly needs to be rotated, and the key in the tail cover assembly is separated from the locking hook part and returns to the second station. In the process, the limiting step structure of the limiting pipe sleeve is matched with the plunger convex part, so that the rotation angle of the tail cover assembly towards the unlocking direction is limited, the angle can be kept consistent with the specified angle of the locking sleeve, the driving surface in the key can be opposite to the guide surface on the locking sleeve, and the stability of the medicine injection device for multiple injections in the using process is improved.

The structure limitation also enables the key to abut against the limiting step structure in the process of moving from the second station to the first station, so that the key is limited from deflecting towards the unlocking direction in the injection process.

Optionally, the tail cap assembly further comprises a fixed ratchet wheel circumferentially limited and mounted on the housing, and the tail cap assembly comprises a tail end ratchet wheel, and the tail end ratchet wheel and the fixed ratchet wheel are connected through a ratchet structure, so that the tail end ratchet wheel can rotate in an unlocking direction relative to the fixed ratchet wheel, and the tail end ratchet wheel is limited from rotating in a back unlocking direction relative to the fixed ratchet wheel; the tail end spring drives the tail end ratchet wheel to have a tendency of always abutting against the end part of the fixed ratchet wheel section.

By adopting the technical scheme, the tail end ratchet wheel is circumferentially and relatively locked with other components in the tail cover assembly, and the tail end ratchet wheel is matched with the fixed ratchet wheel, so that the tail cover assembly and the keys in the tail cover assembly can only rotate along the unlocking direction in the circumferential direction, the tail cover assembly cannot rotate in the direction opposite to the unlocking direction, the stability of the medicine injection device for multiple injections is improved, and the probability of misoperation of the medicine injection device for multiple injections in the use process is reduced.

Optionally, the fixed ratchet is axially slidably mounted on the housing; the locking sleeve and the fixed ratchet are also connected by a ratchet structure such that the locking sleeve is rotatable relative to the fixed ratchet in an unlocking direction and restricts rotation of the locking sleeve relative to the fixed ratchet in a back-to-unlocking direction; the tail end spring drives the fixed ratchet wheel to have a tendency of always abutting against the end of the locking sleeve.

Through adopting above-mentioned technical scheme, the cooperation of locking sleeve and fixed ratchet for the locking sleeve only can rotate towards the unblock direction in circumference, has restricted locking sleeve to rotate towards the unblock direction of keeping away from, thereby has improved the medicine injection device's of many times injection stability and has reduced the medicine injection device of many times injection and has taken place the probability of maloperation in the use. When the locking sleeve rotates relative to the fixed ratchet wheel, the fixed ratchet wheel can impact on the locking sleeve under the driving of the tail end spring every time one ratchet wheel rotates relative to the fixed ratchet wheel, so that a hitting sound is given out to prompt a user that the locking sleeve rotates circumferentially relative to the fixed ratchet wheel.

Optionally, the tail cap assembly further comprises a screw cap which is circumferentially and rotatably mounted at the tail end of the housing.

Through adopting above-mentioned technical scheme, spiral cover circumference rotation installs the tail end at the casing for thereby the user can drive the tail-hood subassembly through rotating the spiral cover and rotate, and the person of facilitating the use rotates whole tail-hood subassembly.

Optionally, the first injection stroke of the locking lug in the locking step structure is an exhaust stroke for exhausting.

Through adopting above-mentioned technical scheme for the medicine injection device of above-mentioned multiple injection can carry out exhaust operation at the in-process of first injection, just also inject to empty when first injection at the medicine injection device of above-mentioned multiple injection, has eliminated the clearance volume between plunger rod and the cassette bottle piston, makes the liquid medicine volume of output can reach standard in next injection.

Optionally, the plunger rod is provided with a plurality of sounding convex teeth at intervals along the axial direction on the outer side wall; the shell is internally provided with a sounding part which is provided with an elastic sounding part which is abutted against the outer side wall of the plunger rod and is used for enabling the sounding convex teeth to deform in an abutting mode.

By adopting the technical scheme, when the plunger rod moves axially towards the injection direction under the action of the driving spring, the elastic sound generating part of the generating piece is driven by the sound generating convex teeth to bend and deform outwards in the radial direction, and after the support of the sound generating convex teeth is lost, the elastic sound generating part restores to the original state and impacts on the outer side wall of the plunger rod, so that the injection prompt sound of 'Da' is emitted in the injection process. When the user hears the snap sound, this indicates that the plunger rod is still moving axially in the injection direction, i.e. that the multi-injection medicament injection device is still in the process of injecting.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the pressure applied to the piston of the cassette bottle by the medicine injection device for multiple times of injection in the injection process is from the driving spring, so that the speed of the medicine injection device for multiple times of injection is kept constant when liquid medicine is input into a patient, the liquid medicine input into the patient in unit time is stable, and the experience of the patient when the liquid medicine is injected is improved;

2. the locking sleeve is driven to rotate towards the unlocking direction by pressing the key, so that the injection operation of the medicine injection device for multiple injections is convenient;

3. when the key moves from the second station to the first station, the locking hook part in the locking sleeve is inserted into the hook groove of the key, so that the key cannot be restored to the second station under the action of the tail end spring, and the probability of liquid medicine waste caused by mistakenly pressing the key by a patient after one-time injection is finished is reduced;

4. the matching of the fixed ratchet wheel and the tail end ratchet wheel, the matching of the fixed ratchet wheel and the locking sleeve, and the matching of the limiting stepped structure in the limiting pipe sleeve and the plunger convex part enable the use of the medicine injection device for multiple injections to have the limitation of operation steps, so that the next operation can not be carried out under the condition that the previous operation is not completed, the stability of the medicine injection device for multiple injections is improved, and the probability of misoperation of the medicine injection device for multiple injections in the use process is reduced;

5. the sound-producing piece is set to help prompt a user that the plunger rod axially moves towards the injection direction, and the probability of liquid medicine waste caused by the fact that the user pulls out the medicine injection device when the medicine injection device for multiple injections is still in the injection process is reduced.

Drawings

Fig. 1 is a schematic view of the structure of the cartridge of the present embodiment.

Fig. 2 is an exploded view of the multi-injection medicine injection device in this embodiment.

Fig. 3 is a schematic cross-sectional view illustrating the connection holder and the rear housing according to the present embodiment.

Fig. 4 is an enlarged schematic view at a in fig. 3.

Fig. 5 is a schematic diagram illustrating the front housing, the connecting socket, and the rear housing in an exploded state according to the present embodiment.

Fig. 6 is a schematic structural diagram of the connecting seat and the retainer in the embodiment.

Fig. 7 is a schematic view of the structure of the holder, the cartridge and the injection needle assembly of this embodiment.

Fig. 8 is a schematic view of the connection seat and the plunger rod in this embodiment.

Fig. 9 is a schematic view of the connection seat, the plunger rod and the driving spring in this embodiment.

Fig. 10 is a schematic structural view of the lock sleeve in the present embodiment.

Fig. 11 is a schematic view of the internal structure of the locking sleeve in this embodiment.

Fig. 12 is a schematic illustration of the mating cross-section of the rear housing, the connecting socket, the plunger rod, the drive spring, the locking sleeve, the tail end assembly and the fixed ratchet at a radial cross-section through the plunger post in this embodiment.

Fig. 13 is a schematic cross-sectional view of the engagement of the rear housing, the connecting socket, the plunger rod, the drive spring, the locking sleeve, the tail end assembly and the fixed ratchet at a radial section passing through the sounding convex teeth in the present embodiment.

Fig. 14 is an enlarged schematic view at B in fig. 13.

Fig. 15 is an exploded schematic view of the rear housing, connecting block, plunger rod, drive spring, tail end assembly and fixed ratchet.

FIG. 16 is a schematic view of the mating of the rear housing, fixed ratchet and locking sleeve.

Fig. 17 is a schematic view of the cooperation of the screw cap, the rear case and the key.

Fig. 18 is a schematic view of the front end structure of the screw cap.

Fig. 19 is a schematic diagram of the front end structure of the key.

FIG. 20 is a schematic view of the key engaging the locking sleeve in the first position.

FIG. 21 is a schematic view of the key in a second position in cooperation with the locking sleeve.

FIG. 22 is a schematic view of the engagement of the button, the tail spring, the tail ratchet and the fixed ratchet.

FIG. 23 is a schematic view of the engagement of the ratchet at the end, the position limiting sleeve and the connecting seat.

Fig. 24 is a schematic view of the engagement of the limiting sleeve, the connecting seat and the plunger rod.

FIG. 25 is a schematic view of the engagement of the stop collar and the trailing ratchet.

Fig. 26 is a schematic structural view of the sounding member.

Description of reference numerals: 11. a front housing; 111. edge buckling; 112. a first guide groove; 12. a connecting seat; 121. a rear insertion part; 1211. a first elastic buckle; 122. a front insertion part; 1221. buckling grooves; 1222. a first guide block; 123. a butt joint plate; 124. inserting grooves; 1241. a second bayonet; 1242. a second guide groove; 125. a drive tube portion; 1251. a drive lumen; 1252. inserting a spring into the column; 1253. a plunger slide groove; 1254. a front drive tube; 1255. a rear drive tube; 127. a fourth bayonet; 13. a rear housing; 131. installing a tube cavity; 132. a containing groove; 1321. accommodating the step surface; 1322. a first bayonet; 14. a positioning ring groove; 15. installing a chute; 16. a tail end portion; 161. a tail cover ring groove; 162. a support ring; 17. a restraining collar; 18. a color development window; 2. a holder; 21. an installation part; 211. a second elastic buckle; 212. a second guide block; 22. a retaining collar; 23. a mounting cavity; 231. a liquid medicine injection opening; 232. the medicine tube is provided with an opening; 24. installing a connector; 25. an injection needle assembly; 251. a needle tube mounting base; 252. injecting a needle tube; 253. a protective outer cover; 3. a plunger rod; 31. a plunger head; 32. a spring slot; 33. a plunger boss; 34. a sounding convex tooth; 4. a locking sleeve; 41. a front body portion; 411. positioning the ring edge; 42. a rear body portion; 43. locking the ladder structure; 4311. a first step surface; 4312. a second step surface; 4313. a third step surface; 4314. a fourth step surface; 4315. a fifth step surface; 44. a second ratchet; 45. a color development convex ring; 451. a color development ring groove; 4521. a first color-displaying block; 4522. a second color development block; 4523. a third color development block; 4524. a fourth color development block; 4525. a fifth color development block; 4526. a sixth color development block; 46. a guide projection; 461. a guide surface; 462. a locking hook portion; 5. a drive spring; 6. fixing the ratchet wheel; 61. a fixed protrusion; 62. a first ratchet; 63. a fourth ratchet; 71. screwing a cover; 711. a limiting bump; 712. limiting and flanging; 713. a flanging ring groove; 714. a first lock block; 72. pressing a key; 721. an accommodating cavity; 722. a front key body; 723. a rear key body; 7231. a first locking groove; 724. a second locking groove; 725. driving the convex plate; 7251. a drive face; 7252. a hook groove; 726. locking the insert column; 7261. a fourth locking groove; 73. a tail end spring; 74. a tail end ratchet wheel; 741. a lower ratchet wheel part; 7411. a second locking bar; 7412. a tail end spring slot; 7413. a tail end spring slot; 742. an upper ratchet portion; 743. a third ratchet; 744. a ratchet wheel through hole; 7441. a ratchet wheel front hole; 7442. a ratchet wheel rear hole; 745. a third locking groove; 746. a third elastic buckle; 75. a limiting pipe sleeve; 751. a limiting pipe part; 7511. limiting the tube cavity; 7512. limiting stepped holes; 7513. a limiting step structure; 75131. a first step side; 75132. a second step side; 75133. a third step side; 75134. a fourth step side; 75135. a fifth step side; 752. a transition duct section; 7521. a transition lumen; 753. a locking tube portion; 7531. locking the lumen; 7532. a third locking bar; 7533. a third bayonet; 754. a structural convex ring; 7541. a structural gap; 755. a fourth locking bar; 8. a sound producing member; 81. an annular top plate; 82. an elastic sound-emitting portion; 83. a fourth elastic buckle; 9. a cartridge bottle; 91. a glass housing; 911. a storage cavity; 912. a bottle cap mounting part; 92. a piston; 93. a bottle cap; 931. a rubber film layer; 932. a metal fixing sleeve.

Detailed Description

The present application is described in further detail below with reference to figures 1-26.

In the present application, when the term "front end portion/end" is used, this refers to the portion/end of the multi-shot drug injection device or the components thereof that is close to the injection area of the human body during injection; accordingly, when the term "back end portion/end" is used, this refers to the portion/end of the multi-shot medicament injection device or the components thereof that are remote from the injection area of the human body during injection. And the state of the multi-shot medicament injection device when not in use is defined as the initial state of the medicament injection device.

Fig. 1 shows a schematic view of the construction of the cartridge 9. Referring to fig. 1, the cartridge 9 is a conventional medical container for storing a liquid medicine, and includes a glass housing 91, a piston 92 installed in the glass housing 91, and a cap 93 installed at a front end of the glass housing 91. The glass case 91 has a cylindrical reservoir cavity 911 for storing a chemical liquid, and the front end of the glass case 91 has a cap mounting portion 912 having a port communicating with the reservoir cavity 911. The piston 92 is installed in the storage cavity 911 and serves to seal a rear end portion of the storage cavity 911 from leakage of the liquid medicine stored in the glass housing 91 from the rear end of the glass housing 91. The bottle cap 93 is mounted on the bottle cap mounting portion 912 of the glass housing 91, and the bottle cap 93 includes a rubber film layer 931 and a metal fixing sleeve 932, wherein the rubber film layer 931 is sleeved on the bottle cap mounting portion 912 and seals and covers the through opening, and the metal fixing sleeve 932 fixes the rubber film layer 931 on the bottle cap mounting portion 912.

The above-described cartridge 9 is mounted in the multi-injection medicine injection device of the present application, and a direction moving from the rear end to the front end is defined as an injection direction, and when the piston 92 moves in the injection direction in the cartridge 9, the piston 92 moves toward the cap mounting portion 912 toward the rear end portion of the glass case 91.

The embodiment of the application discloses a medicine injection device for multiple injections. Fig. 2 is an exploded view of a multi-injection drug injection device. Referring to fig. 2, the medicine injection device for multiple injections comprises a housing, a holder 2 installed in the housing and used for accommodating a cartridge 9, a plunger rod 3 installed in the housing in an axial sliding manner, a locking sleeve 4 installed in the housing in a circumferential rotation manner and sleeved outside the plunger rod 3, a driving spring 5 installed in the housing and driving the plunger rod 3 to have a tendency of moving axially towards the injection direction all the time, a fixed ratchet 6 installed in the housing, and a tail cap assembly installed on the housing in a circumferential rotation manner.

Wherein, the casing is made by plastics, and includes preceding shell 11, connecting seat 12 and backshell 13 along the direction of front end to rear end in proper order. The tail cover assembly comprises a screw cover 71, a key 72, a tail end spring 73, a tail end ratchet 74 and a limit pipe sleeve 75. Wherein the screw cap 71, the key 72, the tail end spring 73, the tail end ratchet 74 and the limit socket 75 are configured to be circumferentially locked with each other.

Referring to fig. 3 and 4, the rear case 13 is constructed in a hollow tubular structure, and the rear case 13 has a mounting lumen 131 having a circular cross-section. The rear housing 13 has a receiving groove 132 formed in a circumferential direction of a front end portion of the mounting cavity 131, and a receiving stepped surface is formed on a bottom surface of the receiving groove 132. The rear housing 13 has two first bayonets 1322 formed on the sidewall of the receiving groove 132 and penetrating through the inner and outer surfaces.

Referring to fig. 3 and 4, the connection holder 12 has a rear insertion part 121 inserted into the cavity of the rear case 13 from the front end direction at the rear end part. The rear insertion part 121 has a hollow cylindrical structure, and two first elastic buckles 1211 corresponding to the two first bayonets 1322 are disposed on an outer wall of the rear insertion part 121. When the rear insertion part 121 is inserted into the rear case 13, the first elastic snap 1211 is snapped from an inner side of the first snap 1322, so that the connection holder 12 can be in a locked state with respect to the rear case 13 in both axial and circumferential directions. And a positioning ring groove 14 is formed between the rear end of the rear insertion-fit part 121 and the receiving stepped surface when the rear insertion-fit part 121 is inserted into the rear case 13.

Referring to fig. 5, the connection holder 12 has a front insertion part 122 at a front end portion. The front plug portion 122 has a ring structure. The front plug part 122 is provided with a circumferentially arranged catch 1221 and an axially arranged first guide block 1222 on an outer side wall. In this embodiment, the front insertion portion 122 is uniformly provided with four of the above-mentioned catching grooves 1221 and two of the above-mentioned first guide blocks 1222 symmetrically arranged in the circumferential direction on the outer side wall. The front case 11 is constructed in a hollow tubular structure with a closed front end.

Referring to fig. 5, the front case 11 is provided at a rear end portion of the inner wall with a catching rib 111 capable of being caught in the catching groove 1221 and a first guide groove 112 for inserting the first guide block 1222. Wherein the front case 11 is provided with a flared structure at the rear end of the first guide groove 112 to facilitate the insertion of the first guide block 1222 into the first guide groove 112. In the present embodiment, four buckling ribs 111 are uniformly arranged on the inner wall of the front shell 11 in the circumferential direction, and correspond to the buckling grooves 1221 one to one, and four first guide grooves 112 are uniformly arranged on the inner wall of the front shell 11 in the circumferential direction.

When the front housing 11 is fastened to the front mating part 122 of the connecting socket 12, the two first guide blocks 1222 are inserted into the two guide grooves, and the four fastening ribs 111 are fastened in the fastening grooves 1221. Since connecting holder 12 and front housing 11 are made of plastic, the user can pull front housing 11 relative to connecting holder 12, so that both buckle rib 111 of front housing 11 and buckle groove 1221 of connecting holder 12 are deformed relatively, and front housing 11 can be taken down from front insertion part 122 of connecting holder 12.

Referring to fig. 5, the connection holder 12 is further provided with an abutting plate 123 between the front insertion part 122 and the rear insertion part 121. When the front and

rear cases

11 and 13 are mounted on the connector holder 12, the rear end of the front case 11 abuts against the abutting plate 123, and the front end of the rear case 13 also abuts against the abutting plate 123.

Referring to fig. 6, the connecting base 12 has a slot 124 formed at a front end thereof. The inner wall of the inserting groove 124 is provided with a second bayonet 1241. The second bayonets 1241 penetrate through the inner and outer surfaces of the connecting socket 12 and are located at the rear insertion part 121. In the present embodiment, the connection seat 12 is provided with two second bayonets 1241, and the two second bayonets 1241 are circumferentially and uniformly arranged on the inner wall of the insertion groove 124. Two second guide grooves 1242 are uniformly arranged on the connecting socket 12 at the front end portion of the inner wall of the insertion groove 124 in the circumferential direction, and a flared structure is also arranged at the front end of the second guide grooves 1242 and is communicated with the front end edge of the connecting socket 12.

Referring to fig. 6, the holder 2 is of a tubular structure and is mounted on the connecting seat 12. The holder 2 is provided with a mounting portion 21 at a rear end portion. The outer wall of the mounting portion 21 is provided with two second elastic buckles 211 which are in one-to-one correspondence with the two second bayonets 1241 and can be buckled into the second bayonets 1241, and the outer wall of the mounting portion 21 is further provided with two second guide blocks 212 which are in one-to-one correspondence with the two second guide grooves 1242 and can be inserted into the second guide grooves 1242. The holder 2 is further provided with a holding convex ring 22 for abutting against the front end of the connecting socket 12.

When the mounting portion 21 of the holder 2 is inserted into the insertion groove 124 of the connection seat 12, the front end of the connection seat 12 abuts against the retaining convex ring 22, the second elastic buckle 211 is buckled into the second bayonet 1241 and abuts against the edge of the front end portion of the second bayonet 1241, and the second guide block 212 is inserted into the second guide groove 1242, so that the holder 2 is locked with respect to the connection seat 12 in the circumferential direction and the axial direction.

Fig. 7 shows a schematic view of the cooperation of the holder 2, the cartridge 9 and the needle assembly 25. Referring to fig. 7, the interior cavity of the holder 2 is configured to receive a cartridge bottle 9. The holder 2 is provided with a mounting cavity 23 in which the cartridge 9 is arranged. The mounting cavity 23 has a drug solution injection opening 231 formed at the front end of the holder 2, and a drug tube mounting opening 232 formed at the rear end of the holder 2. The cage 2 is provided with a mounting nipple 24 at a proximal end, and an outer side wall of the mounting nipple 24 is provided with an external thread.

Needle assembly 25 includes a needle mount 251, an injection needle tube 252, and a protective housing 253. Needle cannula mount 251 is of a cap construction and is threadably mounted to adapter 24. Injection needle tubes 252 are mounted through needle tube mount 251 and are axially disposed. When the needle mount 251 is mounted on the mount fitting 24, the injection needle tube 252 can pierce the rubber film layer 931 of the cassette bottle 9, so that the liquid medicine in the cassette bottle 9 can be output through the injection needle tube 252. A protective shield 253 is mounted on needle mount 251 and covers syringe 252.

Referring to fig. 8 and 9, the connection holder 12 is provided at an end of the rear insertion part 121 with a driving pipe part 125 coaxially arranged with the rear insertion part 121 and having a closed rear end. The driving tube part 125 has an outer diameter smaller than that of the coupling holder 12 so that a stepped surface is formed at the rear end of the coupling holder 12. The driving tube 125 has a driving tube 1251 communicating with the insertion groove 124, and the driving tube 125 is coaxially provided with a spring insertion post 1252 at the rear end of the driving tube 1251 for the driving spring 5 to be inserted.

Referring to fig. 7 and 9, the plunger rod 3 is coaxially installed in the driving lumen 1251, and the front end of the plunger rod 3 is provided with a plunger head 31 for pressing against the piston 92. The plunger rod 3 is coaxially provided with a spring groove 32 at the rear end surface for accommodating the driving spring 5.

When the plunger rod 3 is arranged in the drive lumen 1251, the front end of the drive spring 5 abuts on the front end face of the spring groove 32 and the rear end of the drive spring 5 abuts on the rear end face of the drive lumen 1251, so that the plunger rod 3 has a tendency to move axially always in the injection direction.

Referring to fig. 8 and 9, the plunger rod 3 is circumferentially provided with two plunger protrusions 33 at the rear end portion of the outer side wall. The driving chamber 1251 is provided with plunger chutes 1253 which correspond to the two plunger protrusions 33 one to one and are used for allowing the plunger protrusions 33 to slide axially. The connecting seat 12 is provided with a notch communicating with the plunger slide groove 1253 and used for the plunger convex part 33 to pass through, on the rear end surface of the rear insertion part 121, so that the plunger rod 3 can be mounted to the driving lumen 1251 from the notch of the insertion groove 124.

Referring to fig. 10 and 11, the locking sleeve 4 is a hollow tubular structure. The lock sleeve 4 includes a front body portion 41 and a rear body portion 42 in the front-to-rear direction. The front body portion 41 has an outer diameter larger than the rear body portion 42, and the front body portion 41 also has an inner diameter larger than the rear body portion 42.

Referring to fig. 12 and 13, the front end of the front body portion 41 is provided with a positioning ring rim 411 inserted into the positioning ring groove 14, and when the locking sleeve 4 is installed in the housing, the positioning ring rim 411 is positioned in the positioning ring groove 14 so that the locking sleeve 4 is restricted from moving axially in the housing.

Referring to fig. 11 and 12, the locking sleeve 4 is provided at its inner surface with two locking step structures 43 in one-to-one correspondence with the two plunger protrusions 33. The locking step structure 43 is constituted by a convex portion on the inner wall of the locking sleeve 4, and includes a plurality of locking step surfaces against which the plunger convex portion 33 abuts to restrict the axial movement of the plunger rod 3. Among them, the number of the locking stepped surfaces in the locking stepped structure 43 may be five, six, seven as long as the number of the locking stepped surfaces can be arranged in the locking sleeve 4 and the corresponding locking stepped surfaces can stably support the plunger convex portion 33. In the present embodiment, the locking stepped structure 43 has five locking stepped faces therein. The five locking stepped surfaces are sequentially a first stepped surface 4311, a second stepped surface 4312, a third stepped surface 4313, a fourth stepped surface 4314 and a fifth stepped surface 4315 along the direction from the rear end to the front end. That is, the locking step 43 enables the plunger rod 3 to complete five injection operations. Here, a circumferential direction of an inclination direction of the locking stepped structure 43 in a direction from the front end to the rear end is defined as an unlocking direction.

In an initial state, that is, when the multi-injection medicine injection device is not used, plunger projection 33 of plunger rod 3 abuts against first step 4311, and after locking sleeve 4 is rotated by a predetermined angle in the unlocking direction, plunger projection 33 and first step 4311 are disengaged, an injection stroke is formed between plunger projection 33 and second step 4312, and plunger rod 3 is moved in the injection direction until plunger projection 33 abuts against second step 4312 by drive spring 5. When the second injection is performed, the locking sleeve 4 needs to be rotated again by a specified angle in the unlocking direction. In this case, the width of the locking step surface in the locking step structure 43 is kept consistent, that is, the designated angle of each rotation is also kept consistent. In the present embodiment, the specified angle is 25 °.

Referring to fig. 7, 11 and 12, the first injection stroke between the first step surface 4311 and the second step surface 4312 is a degassing injection stroke, and the height of the degassing injection stroke is 3 mm. The rest two adjacent locking step faces are 10mm in thickness. When the plunger projection 33 slides down the fifth stepped surface 4315, the plunger rod 3 drives the piston 92 of the cartridge 9 to move forward until the piston 92 abuts on the front end of the storage cavity 911, in which process the stroke of the plunger rod 3 is also 10 mm.

Referring to fig. 10 and 11, the outer side wall of the locking sleeve 4 is provided with a color developing convex ring 45 in the circumferential direction. The color development convex ring 45 is provided with a color development ring groove 451 in the circumferential direction of the outer side wall, and color development blocks are arranged at intervals in the circumferential direction of the color development ring groove 451. The number of the color development blocks is six, and the color development blocks sequentially include a first color development block 4521, a second color development block 4522, a third color development block 4523, a fourth color development block 4524, a fifth color development block 4525 and a sixth color development block 4526 in the unlocking direction. And the circumferential included angle between the adjacent color development blocks is 25 deg. The color development blocks are coated with different colors on the outer side surface and used for distinguishing the colors of different color development blocks.

Referring to fig. 13 and 14, the rear case 13 is provided with a color developing window 18 penetrating the inner and outer surfaces on the outer side wall for observing the facing color developing patches.

Referring to fig. 10, 11, 12, and 14, when the plunger projection 33 abuts on the first step surface 4311, the first color development block 4521 faces the color development window 18; when the plunger projection 33 abuts on the second step surface 4312, the second color development block 4522 faces the color development window 18; when the plunger projection 33 abuts on the third step 4313, the third color development piece 4523 faces the color development window 18; when the plunger projection 33 abuts on the fourth step surface 4314, the fourth color development piece 4524 faces the color development window 18; when the plunger projection 33 abuts on the fifth stepped surface 4315, the fifth color development block 4525 faces the color development window 18; when the plunger projection 33 slides down from the fifth stepped surface 4315, the sixth color development block 4526 faces the color development window 18.

Referring to fig. 15, the fixed ratchet 6 is installed in the rear case 13. The fixed ratchet 6 is evenly arranged with two fixing protrusions 61 in the outer side wall circumferential direction. Two mounting sliding grooves 15 which correspond to the two fixing convex parts 61 one to one and are used for sliding the fixing convex parts 61 are uniformly formed in the circumferential direction of the inner wall of the rear shell 13. The two mounting runners 15 are arranged in the axial direction and penetrate both ends of the rear case 13, so that the fixing ratchet 6 can be loaded into the rear case 13 from the front end or the rear end of the rear case 13, and the fixing ratchet 6 can move axially in the rear case 13.

Referring to fig. 16, the fixed ratchet 6 is located on the rear end side of the locking sleeve 4. The fixed ratchet 6 is provided with a ring of first ratchet teeth 62 at a proximal end, the locking sleeve 4 is provided with a ring of second ratchet teeth 44 at a rear end thereof, which are engaged with the first ratchet teeth 62, and the engagement of the first ratchet teeth 62 and the second ratchet teeth 44 forms a ratchet structure between the fixed ratchet 6 and the locking sleeve 4, so that the locking sleeve 4 can rotate relative to the fixed ratchet 6 in an unlocking direction and the locking sleeve 4 is restricted from rotating relative to the fixed ratchet 6 in a reverse unlocking direction. Wherein, the tail cap component is abutted against the far end of the fixed ratchet 6, and drives the fixed ratchet 6 to have the tendency of always abutting against the rear end of the locking sleeve 4.

Referring to fig. 17 and 18, the rear case 13 is provided at a rear end portion with a tail end portion 16 for mounting the screw cap 71. The tail end 16 is of tubular construction arranged coaxially with the rear shell 13. The tail end portion 16 is provided with a tail cover ring groove 161 in the circumferential direction of the front end portion. The forward end of the aft end 16 is also provided with a ring of support rings 162. The screw cap 71 is provided with four stopper protrusions 711 which are capable of being engaged into the tail-cap ring groove 161 and moving in the circumferential direction of the tail-cap ring groove 161, at regular intervals in the circumferential direction at the front end portion of the inner wall. The rotary cover 71 is further provided with an inward-folded limiting flange 712 at the rear end, and a flange ring groove 713 for inserting the rear end edge of the tail end 16 is formed between the limiting flange 712 and the inner wall of the rotary cover 71.

Referring to fig. 17 and 18, the screw cap 71 is made of plastic and has a small thickness so that the screw cap 71 can be mounted on the rear end 16 of the rear case 13 by slight deformation. When the spin cover 71 is mounted on the tail end portion 16, the four limit protrusions 711 of the spin cover 71 are inserted into the tail end annular groove, and the rear end edge of the tail end portion 16 is inserted into the burring annular groove 713 of the spin cover 71, so that the spin cover 71 is rotatably mounted on the tail end portion 16 of the rear case 13, and the axial displacement with respect to the tail end portion 16 is limited.

Referring to fig. 17, the rear case 13 is provided with a ring of restricting convex rings 17 at circumferentially spaced intervals at the rear end portion of the inner wall. Wherein, the limiting convex rings 17 are formed with a fracture at the mounting sliding groove 15 so that the mounting sliding groove 15 is not interrupted.

Referring to fig. 17 and 19, the key 72 is a hollow cylindrical key structure and has a receiving cavity 721 with an open front end. The key 72 includes a front key body 722 and a rear key body 723 in order in a front-to-rear direction. The outer diameter of the rear key 723 is smaller than the outer diameter of the front key 722, and the outer diameter of the front key 722 is larger than the inner diameter of the limiting convex ring 17, so that the key 72 is installed into the rear shell 13 from the front end of the rear shell 13, and the key 72 cannot be disengaged from the rear end opening of the rear shell 13 due to the arrangement of the limiting convex ring.

Referring to fig. 17, the rear key body 723 is uniformly provided with two axially arranged first lock grooves 7231 in the outer side wall circumferential direction. The first lock groove 7231 forms an opening at the rear end of the rear key body 723. The rotary cover 71 is uniformly provided with two first locking blocks 714 which are in one-to-one correspondence with the first locking grooves 7231 and can be inserted into the first locking grooves 7231 on the circumferential direction of the inner ring side surface of the limiting flange 712, so that the rotary cover 71 and the key 72 can be locked relatively in the circumferential direction.

Referring to fig. 20, the push button 72 is provided with two driving protrusions 725 extending toward the locking sleeve 4 at the front end of the front button body 722. A driving surface 7251 is formed between the front edge of the driving lug 725 and the side wall on the side facing the unlocking direction, and a hook groove 7252 is formed on the side wall of the driving lug 725 on the side facing away from the unlocking direction.

The lock sleeve 4 is provided with a guide projection 46 for abutment of the drive projection 725 at the rear end portion of the color development projection ring 45. The guide projection 46 has a guide surface 461 formed between a rear edge thereof and a side wall on a side facing away from the unlocking direction, against which the drive surface 7251 abuts. The locking sleeve 4 is also provided at the rear end portion of the outer wall with a locking hook 462 for insertion into the hook groove 7252 of the driving lug 725. When the locking hook 462 is inserted into the hook groove 7252 of the driving lug 725, the locking hook 462 can be disengaged from the hook groove 7252 by rotating the key 72 relative to the locking sleeve 4 in the unlocking direction.

Referring to fig. 20 and 21, the button 72 is axially slidably mounted on the rear case 13 and has a first position and a second position in the axial direction, and the first position is located at the front end of the second position.

Referring to fig. 17 and 20, when the key 72 is in the first station, the lock hook 462 of the lock sleeve 4 can be inserted into the hook groove 7252 of the key 72 so that the key 72 can be held at the first station.

Referring to fig. 17 and 21, when the push button 72 is at the second working position, the stepped surface of the push button 72 where the front key body 722 and the rear key body 723 are connected abuts inside the restriction collar 17.

Referring to fig. 20 and 21, when the multi-shot medicine injection driving apparatus is in the initial position, the locking sleeve 4 is in the first position, and the locking hook 462 of the locking sleeve 4 is inserted into the hook groove 7252 of the key 72, while the tail spring 73 is in a compressed state, and the key 72 can be rotated 25 ° in the unlocking direction, so that the locking hook 462 of the locking sleeve 4 is disengaged from the hook groove 7252 of the key 72, the key 72 moves from the first position to the second position, and while the driving surface 7251 of the driving lug 725 in the key 72 is aligned with the guiding surface 461 of the locking sleeve 4.

Referring to fig. 19 and 22, the trailing ratchet 74 is disposed within the receiving cavity 721 of the key 72. The trailing ratchet 74 includes a lower ratchet portion 741 and an upper ratchet portion 742 in this order in a front-to-rear direction. The cross sections of the lower ratchet part 741 and the upper ratchet part 742 are circular, and the outer diameter of the lower ratchet part 741 is larger than that of the upper ratchet part 742.

Two axially arranged second locking strips 7411 are uniformly arranged on the outer side wall of the lower ratchet part 741 in the circumferential direction. The inner wall of the key 72 is provided with second locking grooves 724 corresponding to the two second locking strips 7411 one by one and allowing the second locking strips 7411 to be axially slidably mounted, so as to realize the relative locking of the tail ratchet 74 and the key 72 in the circumferential direction.

The lower ratchet part 741 has a tail spring slot 7413 along the edge of the upper ratchet part 742 on the rear end surface. The front end of the tail spring 73 is inserted into the tail spring groove 7413, and the rear end of the tail spring 73 abuts against the top surface of the accommodation cavity 721 of the key 72.

The tail ratchet 74 is circumferentially arranged with one turn of the third ratchet 743 at the bottom. The top surface of the fixed ratchet 6 is provided with a ring of fourth ratchet teeth 63 which mesh with the third ratchet teeth 743. The cooperation of the third ratchet 743 and the fourth ratchet 63 forms a ratchet structure between the tail ratchet 74 and the fixed ratchet 6, which allows the tail ratchet 74 to rotate in the unlocking direction relative to the fixed ratchet 6 and restricts the rotation of the tail ratchet 74 in the back-to-back unlocking direction relative to the fixed ratchet 6. Wherein, the tail end spring 73 drives the tail end ratchet to have the tendency of always abutting against the rear end of the fixed ratchet 6.

Referring to fig. 23, the limit pipe housing 75 includes a limit pipe portion 751, a transition pipe portion 752 connected to a rear end of the limit pipe portion 751, and a lock pipe portion 753 connected to a rear end of the transition pipe portion 752 in this order from a front end to a rear end. The lumen of the limiting tube 75 comprises, in order in the direction from the front end to the rear end, a limiting lumen 7511 corresponding to the limiting tube portion 751, a transition lumen 7521 corresponding to the transition tube portion 752, and a locking lumen 7531 corresponding to the locking tube portion 753. Wherein, the cross sections of the limiting tube cavity 7511, the transition tube cavity 7521 and the locking tube cavity 7531 are all circular, and the outer diameter is gradually reduced.

Referring to fig. 23, the drive tube portion 125 includes a front drive tube 1254 and a rear drive tube 1255 in this order in the front-to-rear direction. The outer diameter of the front drive tube 1254 is larger than the outer diameter of the rear drive tube 1255. Wherein a plunger chute 1253 is disposed on the front drive tube 1254. When the limit tube housing 75 is mounted outside the drive tube part 125, the limit tube part 751 is arranged outside the front drive tube 1254, and the rear end of the front drive part abuts on the stepped surface where the limit tube cavity 7511 and the transition tube cavity 7521 communicate; the transition tube portion 752 is disposed outside the rear drive tube 1255, and the rear end of the rear drive tube 1255 abuts on a stepped surface where the transition lumen 7521 and the lock lumen 7531 communicate.

Referring to fig. 24, the stopper tube portion 751 is provided with a stopper stepped hole 7512 through which the plunger convex portion 33 passes. The stopper stepped hole 7512 is provided with a stopper stepped structure for abutting against the plunger convex portion 33 on a side of the plunger convex portion 33 facing away from the unlocking direction. The limiting step structure is a limiting step cross section and sequentially comprises a first step side 75131, a second step side 75132, a third step side 75133, a fourth step side 75134 and a fifth step side 75135 in the direction from the rear end to the front end.

Referring to fig. 11 and 24, when plunger projection 33 is placed on first step surface 4311, first step side 75131 is located on the side of plunger projection 33 facing away from the unlocking direction, and the circumferential angle between first step side 75131 and plunger projection 33 is also 25 °; when plunger tab 33 is placed on second step surface 4312, second step side 75132 is located on the side of plunger tab 33 facing away from the unlocking direction, and the circumferential angle between second step side 75132 and plunger tab 33 is also 25 °; when plunger lobe 33 rests on third step face 4313, third step side 75133 is located on the side of plunger lobe 33 facing away from the unlocking direction, and the circumferential angle between third step side 75133 and plunger lobe 33 is also 25 °; when the plunger projection 33 is placed on the fourth step surface 4314, the fourth step side 75134 is located on the side of the plunger projection 33 facing away from the unlocking direction, and the circumferential angle between the fourth step side 75134 and the plunger projection 33 is also 25 °; when plunger tab 33 rests on fifth stepped surface 4315, fifth stepped side 75135 is located on the side of plunger tab 33 facing away from the unlocking direction, and the circumferential angle between fifth stepped side 75135 and plunger tab 33 is also 25 °.

The retainer tube housing 75 is further provided with a structural collar 754 at the front outer edge thereof. The structural collar 754 has a structural notch 7541 formed therein for passage of the plunger boss 33 resting on the fifth step side 75135. Wherein, after the liquid medicine in the cassette bottle 9 is injected, the plunger convex part 33 is arranged in the structure gap 7541 to realize the circumferential locking of the limit sleeve 75.

Referring to fig. 23 and 25, the trailing ratchet 74 has a coaxially arranged ratchet through hole 744. The ratchet through hole 744 sequentially includes a ratchet front hole 7441 and a ratchet rear hole 7442 along the front end to rear end direction, and the aperture of the ratchet front hole 7441 is larger than that of the ratchet rear hole 7442. When the rear end portion of the stopper tube 75 is inserted into the ratchet through hole 744 of the rear ratchet 74, the rear end of the transition tube portion 752 abuts on the stepped surface at the junction of the ratchet front hole 7441 and the ratchet rear hole 7442.

Referring to fig. 23 and 25, the rear ratchet 74 is provided with two axially arranged third locking grooves 745 uniformly circumferentially on the inner wall of the ratchet rear hole 7442. The locking tube portion 753 is provided with two third locking ribs 7532 arranged axially and fitted into the third locking grooves 745 uniformly in the circumferential direction on the outer side wall.

Referring to fig. 19 and 25, the key 72 further has a locking post 726 coaxially disposed on the inner top surface of the receiving cavity 721. The locking studs 726 are circumferentially and uniformly arranged with two axially arranged fourth locking grooves 7261 on the outer side wall. The locking tube portion 753 is circumferentially arranged at an inner wall with two fourth locking strips 755 that correspond one-to-one to the two fourth locking grooves 7261 and can be inserted into the fourth locking grooves 7261.

Referring to fig. 25, the tail ratchet 74 is further provided with two third elastic catches 746 arranged symmetrically about the axis of the tail ratchet 74 at the upper ratchet portion 742. The locking tube portion 753 is provided with third notches 7533 on an outer side wall, wherein the third notches 7533 correspond to the third elastic buckles 746 one by one and are used for clamping the third elastic buckles 746.

Referring to fig. 13 and 26, the plunger rod 3 is provided with two sets of sound emitting teeth 34 on the outer side wall, which are axisymmetric with respect to the axis of the plunger rod 3. Each set of sound lobes 34 includes a plurality of sound lobes 34 spaced apart in the axial direction.

The sound producing component 8 of the connecting base 12 in the inserting groove 124. The sounding part 8 comprises an annular top plate 81 which is abutted against the inner top surface of the insertion groove 124, two elastic sounding parts 82 which are connected to the inner edge of the annular top plate 81 and correspond to the two groups of sounding convex teeth 34 one by one, and two fourth elastic buckles 83 connected to the outer edge of the annular top plate 81.

Wherein the elastic sound-generating portion 82 extends towards the front end, the end of the elastic sound-generating portion 82 abuts against the outer side wall of the plunger rod 3, when the plunger rod 3 moves towards the injection direction, the elastic sound-generating portion 82 deflects radially under the guidance of the sounding convex teeth 34, and after the support of the sounding convex teeth is lost, the elastic sound-generating portion 82 recovers to deform and impact on the outer side wall of the plunger rod 3, and a rattling and rattling sound is generated.

The two fourth elastic catches 83 also extend in the front direction. The side wall of the rear plug-in part 121 of the connection seat 12 is provided with a fourth bayonet 126 for the fourth elastic buckle 83 to be installed.

With reference to fig. 1 to 26, the usage steps of the multi-injection medicine injection device are as follows:

1. removing the front housing 11 of the multi-injection medication injection device, mounting the rear needle assembly 25 on the holder 2, and removing the protective cover 253 of the needle assembly 25;

2. carrying out an exhaust operation:

rotating the knob in the unlocking direction, and because all parts in the tail cover assembly are circumferentially locked, synchronously rotating the key 72, the tail end ratchet 74 and the limiting pipe sleeve 75 until the first step side 75131 in the limiting pipe sleeve 75 is abutted with the plunger convex part 33, and at the moment, integrally rotating the tail cover assembly for 25 degrees;

the locking hook 462 of the locking sleeve 4 is disengaged from the hook groove 7252 of the key 72, and the key 72 is moved toward the rear end after losing the locking of the locking hook 462 until it abuts against the restraining collar 17 of the rear case 13, at which time the driving surface 7251 of the driving projection 725 of the key 72 is axially opposed to the guide surface 461 of the guide projection 46 of the locking sleeve 4;

pressing the button 72 in the front end direction causes the driving surface 7251 of the driving lug 725 on the button 72 to abut against the guiding surface 461 of the guiding projection 46 and drive the locking sleeve 4 to rotate 25 ° in the unlocking direction, so that the plunger projection 33 of the plunger rod 3 loses the support of the first step surface 4311 on the locking sleeve 4, the plunger rod 3 moves in the front end direction under the action of the driving spring 5 until the plunger projection 33 is supported by the second step surface 4312, and since the distance between the first step surface 4311 and the second step surface 4312 is 3mm, the plunger rod 3 pushes the piston 92 on the cartridge 9 by 3mm in the front end direction, which can eliminate the assembly gap between the front end of the plunger rod 3 and the piston 92 of the cartridge 9;

3. and (3) injection operation:

rotating the knob in the unlocking direction until the first step side 75131 in the limiting sleeve is abutted with the plunger convex part 33, and at the moment, integrally rotating the tail end assembly for 25 degrees; the locking hook 462 of the locking sleeve 4 is disengaged from the hook groove 7252 of the key 72, and the key 72 moves to the rear end after losing the locking of the locking hook 462 until it abuts against the positioning ring groove 14 of the rear housing 13, at which time the driving surface 7251 of the driving lug 725 on the key 72 is axially aligned with the guiding surface 461 of the guiding projection 46 on the locking sleeve 4;

the injection needle tube 252 is pricked into a part to be injected of a patient, the key 72 is pressed towards the front end direction, the driving surface 7251 of the driving convex plate 725 on the key 72 abuts against the guiding surface 461 of the guiding convex part 46, the locking sleeve 4 is driven to rotate 25 degrees towards the unlocking direction, the plunger convex part 33 of the plunger rod 3 loses the support of the second step surface 4312 on the locking sleeve 4, the plunger rod 3 moves towards the front end direction under the action of the driving spring 5 until the plunger convex part 33 is supported by the third step surface 4313, and the distance between the second step surface 4312 and the third step surface 4313 is 10mm, so that the plunger rod 3 pushes the piston 92 on the cassette bottle 9 by 10mm towards the front end direction, and the liquid medicine in the cassette bottle 9 is input into the patient;

4. after the injection is completed, the injection needle assembly 25 is detached from the holder 2, and the front shell 11 is covered on the front insertion part 122 of the connecting seat 12;

5. and (3) when the next injection is carried out, the front shell 11 is detached, and the step 3 is repeated, so that the next injection can be completed. In the present embodiment, referring to fig. 20 and 21, when the multi-shot medicine injection driving device is in the initial position, the fixing protrusion 61 of the fixing ratchet 6 is located in the hook groove 7252 of one of the driving protrusions 725 of the push button 72; when the multi-injection medicine injection driving device completes 4 injections, the key 72 rotates by 125 ° relative to the fixed ratchet, and the fixed protrusion 61 of the fixed ratchet 6 abuts against the other side of the driving protrusion 725 of the key 72 facing the unlocking direction, so that the tail cap assembly cannot rotate further in the unlocking direction.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The medicine injection device for multiple injections is characterized by comprising a shell, a plunger rod (3) which is axially slidably mounted on the shell, a driving spring (5) mounted in the shell, and a locking sleeve (4) which is circumferentially and rotatably mounted in the shell and sleeved on the outer side of the plunger rod (3); a plunger convex part (33) is arranged on the outer side of the plunger rod (3); the drive spring (5) drives the plunger rod (3) to always have a tendency to move towards the injection direction; the locking sleeve (4) is provided with a locking step structure (43) for the plunger convex part (33) to abut to restrain the plunger rod (3) from moving towards the injection direction;

wherein a circumferential direction of an inclination direction of the locking stepped structure (43) in a direction from the front end to the rear end is defined as an unlocking direction; locking sleeve (4) rotate the appointed angle towards the unblock direction after, plunger convex part (33) with locking stair structure (43) break away from and with form the injection stroke between the next level ladder face of locking stair structure (43) under drive spring's (5) effect, plunger rod (3) move to the injection direction until plunger convex part (33) with the next level ladder face butt of locking stair structure (43).

2. A multiple injection medicament injection apparatus according to claim 1, further comprising a tail cap assembly (7); the tail cap assembly (7) is rotatably mounted on the housing, the components in the tail cap assembly (7) being configured to be circumferentially interlocked with each other; the tail cover assembly (7) comprises a key (72) and a tail end spring (73), the key (72) is installed on the shell and is provided with a first station and a second station in the axial direction, and the second station is located behind the first station; the key (72) is circumferentially limited when moving from the second station to the first station; the locking sleeve (4) has a guide surface (461) arranged in the direction of the rear end; the push button (72) has a drive surface (7251) for abutting against the guide surface (461) to drive the locking sleeve (4) to rotate in the unlocking direction.

3. A multiple injection medication injection device according to claim 2, wherein said locking sleeve (4) is further provided with a locking hook (462), said key (72) being provided with a hook groove (7252); the hook groove (7252) is configured to be inserted by the lock hook (462) when the key (72) is in the first station, restricting movement of the key (72) in the axial direction.

4. A multiple injection medicament injection apparatus according to claim 3, wherein the key (72) has a drive cam (725) extending in the direction of the locking sleeve (4), the drive surface (7251) and the hook groove (7252) being provided on the drive cam (725).

5. A multiple-injection medicament injection apparatus according to claim 3, wherein the tail cap assembly (7) comprises a limit sleeve (75) fitted over the outside of the plunger rod (3), the limit sleeve (75) is provided with a limit step structure for abutting against the plunger protrusion (33), the limit step structure is located on a side of the plunger protrusion (33) facing away from the locking step structure, and the limit step structure is configured such that the driving surface (7251) is opposite to the guiding surface (461) when the plunger protrusion (33) abuts against the limit step structure.

6. A multiple injection medicament injection apparatus according to any of claims 2 to 5, further comprising a fixed ratchet (6) circumferentially stop-mounted on the housing, the tail cap assembly (7) comprising a tail ratchet (74), the tail ratchet (74) and the fixed ratchet (6) being connected by a ratchet arrangement such that the tail ratchet (74) is rotatable relative to the fixed ratchet (6) in an unlocking direction and rotation of the tail ratchet (74) relative to the fixed ratchet (6) in a reverse unlocking direction is limited; the tail end spring (73) drives the tail end ratchet wheel (74) to have a tendency of always abutting against the end of the fixed ratchet wheel (6) section.

7. A multiple injection medicament injection apparatus according to claim 6, in which the fixed ratchet (6) is axially slidably mounted on the housing; the locking sleeve (4) and the fixed ratchet (6) are also connected by a ratchet structure, such that the locking sleeve (4) can rotate relative to the fixed ratchet (6) in an unlocking direction and the locking sleeve (4) is restricted from rotating relative to the fixed ratchet (6) in a direction facing away from the unlocking direction; the tail end spring (73) drives the fixed ratchet wheel (6) to have a tendency of always abutting against the end of the locking sleeve (4).

8. A multiple injection medicament injection apparatus according to claim 2, wherein the tail cap assembly (7) further comprises a screw cap (71) mounted for circumferential rotation on the housing tail end.

9. A multiple injection medication injection device according to claim 1, wherein: the first injection stroke of the locking cam in the locking step structure (43) is an exhaust stroke for exhausting.

10. A multi-injection medicament injection device according to claim 1, wherein the plunger rod (3) is axially spaced at an outer side wall with a plurality of sound emitting lobes (34); be provided with sound production spare (8) in the casing, sound production spare (8) have the butt and be in the lateral wall of plunger rod (3) just is used for supplying elasticity sound production portion (82) that sound production dogtooth (34) contradict the deformation.