CN105288790A - Syringe - Google Patents

Abstract

The invention discloses a syringe. The syringe is used with a medicament bottle and a syringe needle and comprises an outer protecting shell, a coupling ring, a medicament bottle cover shell, an inner sleeve, a two-way spiral guide tube group, a screw joint ring, a one-way ratchet, a spiral push rod and an injection push rod group. The coupling ring is arranged at the front end of the outer protecting shell and combined with the medicament bottle cover shell to hold the medicament bottle. The inner sleeve, the two-way spiral guide tube group, the screw joint ring, the one-way ratchet, the spiral push rod, the injection push rod group and the like are jointly arranged in the outer protecting shell; the injection push rod group can be straightly and quickly pulled backwards and then straightly pushed for injection; a large-pitch stroke structure of the two-way spiral guide tube group and a small-pitch stroke structure between the screw joint ring and the spiral push rod are matched to convert straight push power into rotating power, and a large-stroke rotating thrust is converted into a small-stroke rotating injection thrust, so that quantitative medicament injection is realized. In addition, labor saving is realized by means of simple cyclic opening and closing operations.

Description

Syringe with a needle

Technical Field

The present invention relates to an injector, and more particularly, to an injector with safety control and labor saving functions.

Background

For the purpose of quantitative injection of medicine, counting the number of injections, and limited reuse of the syringe, the conventional syringes generally include a metering syringe and a metering syringe. In the known metering injector, a driving mechanism composed of a plurality of driving components is arranged in an injector shell and connected with a push rod, so that a medicament bottle is arranged in the injector shell, a needle is arranged at the front end of the injector shell and connected with the medicament bottle, when in injection, the needle pierces a preset part of a human body, and the push rod is controlled by the driving component which drives the driving mechanism to move in a linkage manner by pressing the rear end of the push rod, so that a piston in the medicament bottle is pushed to move for a preset stroke to output a medicament with a preset dosage through the needle.

Although the known metering syringe achieves the purpose of quantitatively delivering a medicine, the syringe is limited in the interlocking of the driving parts of the driving mechanism of the syringe during the use and operation, and the syringe has a problem that the operation of the syringe is laborious.

Disclosure of Invention

The invention aims to provide a syringe to solve the problem of labor-consuming operation of the existing metering type syringe.

The technical solution proposed by the invention is as follows: there is provided a syringe for use in combination with a vial and a needle, the syringe comprising:

the outer protecting shell is a hollow body with openings formed at the front end and the rear end;

the joint lantern ring is assembled at the front end of the outer casing, an inner ring part is arranged in the joint lantern ring, and a unidirectional ratchet groove with a plurality of single inclined ratchets is formed in the inner ring part;

a medicine bottle casing assembled on the front end of the joint sleeve ring for fixing the medicine bottle, wherein the front end of the medicine bottle casing can be detachably assembled on the needle head;

the inner sleeve is arranged in the outer protective shell, and the front end of the inner sleeve is fixed in the joint sleeve ring;

a bidirectional spiral guide pipe group, which comprises an outer spiral guide pipe and an inner spiral guide pipe, wherein the outer spiral guide pipe is arranged in the inner sleeve pipe, the outer spiral guide pipe comprises a spiral pipe part and a pipe end formed at the front end of the spiral pipe part, a spiral guide groove is formed on the inner peripheral wall of the spiral pipe part, a plurality of single oblique ratchet elastic pieces are formed on the outer peripheral surface of the pipe end, the ratchet elastic pieces are respectively abutted against single oblique ratchets of a one-way ratchet groove jointed with the lantern ring, so that the outer spiral guide pipe can only rotate in one direction, the inner spiral guide pipe is arranged in the inner sleeve pipe and the outer spiral guide pipe, a plurality of spiral guide blocks are arranged on the outer peripheral surface of the front section of the inner spiral guide pipe, the spiral guide blocks are arranged in the spiral guide groove of the outer spiral guide pipe, so that the inner spiral guide pipe can rotate in the outer spiral guide pipe for a preset stroke distance;

the screw connection ring is assembled and positioned in the pipe end of the external spiral conduit, and a screw hole is formed in the screw connection ring;

the unidirectional ratchet wheel is arranged in the unidirectional ratchet tooth groove of the inner spiral catheter and comprises a wheel body and a plurality of single oblique ratchet elastic pieces formed on the peripheral surface of the wheel body, a middle hole is formed in the wheel body, and the single oblique ratchet elastic pieces are meshed with single oblique ratchets in the unidirectional ratchet tooth groove;

the spiral push rod comprises a dose control section, the peripheral surface of the dose control section is provided with threads, a shaft hole is formed in the spiral push rod, the spiral push rod is arranged in the bidirectional spiral guide pipe group, and the dose control section of the spiral push rod is in threaded connection with the inside of the threaded connection ring and used for extending into the medicament bottle to apply thrust; and

an injection push rod group comprises an injection push rod and a push rod end cover, the injection push rod comprises a rod body and a pressing end part arranged at the rear end of the rod body, the rod body of the injection push rod penetrates through and is fixedly connected with a central hole of the one-way ratchet wheel, the rod body can axially and slidably penetrate through a shaft hole of the spiral push rod, the rear end and the pressing end part of the rod body of the injection push rod are positioned outside the inner spiral guide pipe, the push rod end cover is sleeved outside the pressing end part of the injection push rod, and the rear end of the inner spiral guide pipe is pivotally arranged in the push rod end cover, so that the injection push rod group can be circularly opened and closed by combining the one-way ratchet wheel, the.

In the above syringe, the rear end of the inner sleeve forms a non-return key and a limit flange, the outer peripheral surface of the rear section of the inner spiral conduit forms a plurality of non-return annular threads and is provided with an axial guide groove with a predetermined length, the non-return key can be stopped at the non-return annular threads of the inner spiral conduit to prevent the inner spiral conduit from moving forward, the non-return key is converted to the axial guide groove to enable the inner spiral conduit to be driven to move forward, and the limit flange limits the backward movement position of the inner spiral conduit.

In the above-mentioned injector, the shaft hole of the screw rod and the rod body of the injection push rod are in a non-circular shape corresponding to each other.

In the above syringe, the outer peripheral surface of the screw ring is formed with a positioning protrusion extending in the axial direction, the inner wall of the tube end of the outer screw tube is formed with a positioning recess, and the screw ring is positioned in the tube end of the outer screw tube by the engagement of the corresponding positioning protrusion and positioning recess.

In the above syringe, the front and rear ends of the joint ring are respectively a joint ring part and a group of joint ring parts, the joint ring part is arranged in the outer casing, a plurality of hooks are arranged between the inner ring part and the joint ring part of the joint ring, and an inner ring is arranged between the joint ring part and the inner ring part of the joint ring; the front end of the inner sleeve extending into the joint lantern ring is provided with a clamping groove, the clamping groove is used for clamping a clamping hook of the joint lantern ring into the clamping groove correspondingly, the inner ring is sleeved outside the clamping hook, and the inner sleeve is fixedly connected with the joint lantern ring.

In the above syringe, a piston top block is arranged at the front end of the dosage control section of the spiral push rod.

The invention has the advantages that the invention can quickly pull the injection push rod to the position ready for injection in a straight-backward pulling way after the syringe is assembled with the medicament bottle and the needle head is arranged, and when the injection push rod group is pressed in the straight direction, the straight-direction pressing force is converted into the rotating force and the large-stroke rotating thrust is converted into the small-stroke rotating injection thrust through the combined structure of the spiral guide groove of the outer spiral conduit and the large-pitch stroke of the spiral guide block of the inner spiral conduit matched with the screw hole of the screw joint and the screw thread of the spiral push rod to achieve the purposes of quantitative injection of the medicament and good use safety, and the invention of the linkage mechanism of the injection push rod group combined with the one-way ratchet wheel, the two-way spiral guide tube group, the screw thread ring and the spiral push rod is adopted when the syringe is used, so that the operation process of quantitative injection can achieve the effect of saving labor by a simple operation mode of circular opening and closing.

The invention can also make the injection push rod group of the injector pull out backwards to the preset position through the combination structure of the check key of the inner sleeve and the check ring thread of the inner spiral conduit to press the injection push rod group for injection, and the check key at the rear end of the inner sleeve is matched with the check ring thread on the peripheral surface of the inner spiral conduit to generate the function of stopping and limiting, the inner spiral conduit can not retract due to error pressure in the process of pulling out the inner spiral conduit along with the injection push rod group, and the injector can ensure that the injection dosage can reach the set injection dosage each time.

In addition, the injector also comprises a pen cover, so that the pen cover can be covered under the condition that the needle head of the injector is detached, and the injector can be ensured to be replaced by a new needle head every time the injector is used.

Drawings

The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein,

fig. 1 is a perspective exploded view of a preferred embodiment of the syringe of the present invention and a needle and needle cover.

Fig. 2 is an exploded perspective view of another perspective view of a portion of the components of the injector of fig. 1.

Fig. 3 is a cross-sectional view of the preferred embodiment of the injector shown in fig. 1 and 2 without the needle and cap.

Figure 4 is a side sectional view of the section line location a-a shown in figure 3.

Figure 5 is a side sectional view of the section line location B-B shown in figure 3.

Fig. 6 is an exploded view of the preferred embodiment of the injector of fig. 1-3 with the vial sleeve removed and the pen cap, needle, and needle cover.

Fig. 7 is a cross-sectional view of the preferred embodiment of the injector of fig. 1-3 with the pen cap removed, the needle and needle cap attached, and the plunger pulled out to a predetermined position.

Fig. 8 is a cross-sectional view of the preferred embodiment of the syringe of fig. 1-3 with the needle cover removed and the plunger depressed to initiate an injection.

FIG. 9 is a cross-sectional view of the preferred embodiment of the syringe of FIGS. 1-3 after the plunger is depressed to inject a metered dose of medicament.

The reference numbers illustrate:

1 Syringe 2 medicament bottle

2A piston 3 needle

4 needle cover and 5 pen cover

10 outer casing 11 joint end

20 engaging collar 21 engaging ring portion

22 inner ring part of connecting ring part 23

24 one-way ratchet groove 25 hook

26 inner ring

30 medicine bottle jacket

40 inner sleeve 41 clamping groove

42 non-return key 43 limit stop edge

50 external spiral guide pipe of bidirectional spiral guide pipe group 51

511 spiral pipe part 512 ring end wall

513 tube end 514 spiral guide groove

515 ratchet spring 516 positioning concave part

52 internal spiral conduit 521 spiral guide block

522 non-return ring thread 523 axial guide groove

524 one-way ratchet groove 525 pivoting part

60 screw connection ring 61 screw hole

62 positioning convex part

70 one-way ratchet wheel 71 wheel body

72 single inclined ratchet spring 73 central hole

80 helical push rod 81 dose control section

82 limiting flange 83 shaft hole

84 piston top block

90 injection push rod group 91 injection push rod

911 rod body 912 pressing end

913 positioning block 92 push rod end cap

Detailed Description

The technical means adopted by the invention to achieve the preset purpose are further described below by combining the accompanying drawings and the preferred embodiments of the invention.

Referring to fig. 1 and 2, a preferred embodiment of the syringe 1 of the present invention is disclosed, the syringe 1 is used in combination with a medicament bottle 2, a needle 3 and a needle cover 4, the syringe 1 mainly comprises an outer sheath 10, an engaging collar 20, a medicament bottle casing 30, an inner cannula 40, a bidirectional helical guide tube set 50, a screw ring 60, a one-way ratchet 70, a helical push rod 80 and an injection push rod set 90, or the syringe 1 further comprises a pen cover 5.

As shown in fig. 1 and 2, the outer casing 10 is a hollow body with openings formed at front and rear ends, and the front end of the outer casing 10 is a combination end 11.

As shown in fig. 1 and 2, the joint ring 20 includes a joint ring portion 21, a set of joint ring portions 22 and an inner ring portion 23, the set of joint ring portions 22 and the joint ring portion 21 are respectively located at the front end and the rear end of the joint ring 20, the inner ring portion 23 is located inside the joint ring 20, the joint ring 20 is assembled by placing the joint ring portion 21 into the joint end 11 of the outer casing 10, and the inner ring portion 23 forms a one-way ratchet tooth groove 24 having a plurality of single oblique ratchet teeth therein. As shown in fig. 3, in the preferred embodiment, the engaging collar 20 has a plurality of hooks 25 between the inner ring portion 23 and the engaging ring portion 21, and an inner ring 26 can be further disposed between the engaging ring portion 21 and the inner ring portion 23 of the engaging collar 20.

As shown in fig. 1 and 2, the vial casing 30 is assembled on the engagement ring 21 at the front end of the engagement collar 20 to fix a vial 2 therein. The front end of the vial case 30 is adapted to receive a needle 3.

As shown in fig. 1 to 3, the inner sleeve 40 is installed inside the outer casing 10, the front end of the inner sleeve 40 extends into the joint ring portion 21 of the joint collar 20 and is sleeved outside the inner ring portion 23 for fixation, in the preferred embodiment, a clamping groove 41 is provided at the front end of the inner sleeve 40 extending into the joint collar 20, the clamping hook 25 of the joint collar 20 is provided by the clamping groove 41 to be correspondingly clamped therein, and is sleeved outside the clamping hook 25 by the inner ring 26, so that the inner sleeve 40 is fixedly joined with the joint collar 20, the rear end of the inner sleeve 40 extends outside the outer casing 10, and a check key 42 and a limit stop edge 43 are formed at the rear end of the inner sleeve 40.

As shown in fig. 1 to 3, the bidirectional spiral guide tube set 50 includes an outer spiral guide tube 51 and an inner spiral guide tube 52, the outer spiral guide tube 51 is disposed in the inner sleeve 40, the outer spiral guide tube 51 includes a spiral tube portion 511, a ring end wall 512 and a tube end 513 protruding forward from the ring end wall 512 are formed at a front end of the spiral tube portion 511, a spiral guide groove 514 is formed at an inner peripheral wall of the spiral tube portion 511, a plurality of single oblique ratchet spring pieces 515 are formed at an outer peripheral surface of the tube end 513, and an axially extending positioning recess 516 is formed at an inner wall of the tube end 513, as shown in fig. 3 and 4, the tube end 513 of the outer spiral guide tube 51 extends into the inner ring portion 23 of the engaging collar 20, and the ratchet spring pieces 515 respectively abut against the single oblique ratchet grooves 24 of the engaging collar 20, so that the ratchet teeth of the outer spiral guide tube 51 can only rotate in.

As shown in fig. 1 to 3, in the bidirectional spiral guide tube set 50, the inner spiral guide tube 52 is installed in the inner sleeve 40 and the outer spiral guide tube 51, the outer peripheral surface of the front section of the inner spiral guide tube 52 is provided with a plurality of spiral guide blocks 521, the spiral guide blocks 521 are inserted into the spiral guide grooves 514 of the outer spiral guide tube 51, the inner spiral guide tube 52 can rotate in the outer spiral guide tube 51 for a predetermined distance by the cooperation of the spiral guide blocks 521 and the spiral guide grooves 514, the outer peripheral surface of the rear section of the inner spiral guide tube 52 forms a plurality of check ring threads 522 arranged at intervals and has an axial guide groove 523 with a predetermined length, the check ring threads 522 are in a single oblique direction, the inner section of the inner spiral guide tube 52 forms a unidirectional ratchet groove 524 with a plurality of unidirectional ratchet teeth, the unidirectional ratchet teeth of the unidirectional ratchet groove 524 are in the same oblique direction as the unidirectional ratchet teeth of the engaging collar 20, the rear end of the internal spiral duct 52 forms a pivot portion 525, the pivot portion 525 of the internal spiral duct 52 can extend out of the rear end of the inner sleeve 40, and the non-return key 42 at the rear end of the inner sleeve 40 can change positions between the non-return annular thread 522 at the rear section of the internal spiral duct 52 and the non-return annular thread extending into the axial guide groove 523. As shown in fig. 3 and 5, when the check key 42 extends into the axial guide slot 523, the inner spiral duct 52 can move forward along the axial direction, and the check key 42 abuts against the check ring thread 522 of the inner spiral duct 52, so that the inner spiral duct 52 can be prevented from being pressed by mistake and moving linearly forward along the axial direction.

As shown in fig. 1 to 3, the screw ring 60 is axially installed in the pipe end 513 of the outer screw conduit 51, a screw hole 61 is formed in the screw ring 60, and the pitch of the screw hole 61 is smaller than that of the screw guide groove 514. In the preferred embodiment, the outer peripheral surface of the threaded ring 60 forms an axially extending positioning protrusion 62 that is correspondingly engaged with the positioning recess 516 of the outer spiral guide 51, so that the threaded ring 60 and the outer spiral guide 51 are coupled together.

As shown in fig. 1 to 3, the unidirectional ratchet 70 is installed in the unidirectional ratchet groove 524 of the inner spiral conduit 52, the unidirectional ratchet 70 includes a wheel body 71 and a plurality of single oblique ratchet spring pieces 72 formed on the outer circumferential surface of the wheel body 71, a middle hole 73 is formed in the wheel body 71, the shape of the middle hole 73 corresponds to the non-circular shaft hole of the spiral push rod 80, the single oblique ratchet spring piece 72 of the unidirectional ratchet 70 and the single oblique ratchet spring piece 515 of the tube end 513 of the outer spiral conduit 51 are in the same oblique direction, as shown in fig. 5, the single oblique ratchet spring piece 72 is engaged with the unidirectional ratchet in the unidirectional ratchet groove 524.

As shown in fig. 1 to fig. 3, the helical push rod 80 has a dose control section 81, a thread is disposed on the outer peripheral surface of the dose control section 81, a limit flange 82 is formed at the lateral edge of the dose control section 81 in the middle section of the helical push rod 80, a non-circular shaft hole 83 is formed in the helical push rod 80, the helical push rod 80 is disposed in the bidirectional helical guide tube set 50, the dose control section 81 of the helical push rod 80 is screwed through the inside of the screw ring 60 and can extend into the medicine bottle 2 to directly push the piston 2A, or a piston top block 84 can be disposed at the front end of the dose control section 81 of the helical push rod 80, so that the helical push rod 80 indirectly pushes the piston 2A in the medicine bottle 2 through the piston top block 84.

As shown in fig. 1 to 3, the injection plunger assembly 90 includes an injection plunger 91 and a plunger end cap 92, the injection plunger 91 includes a rod 911 and a pressing end 912 disposed at the rear end of the rod 911, the cross-sectional shape of the rod 911 corresponds to the non-circular shaft hole 83 in the screw 80 and the non-circular central hole 73 in the one-way ratchet 70, in the preferred embodiment, the non-circular cross-sectional shape of the rod 911 is a gear, a polygon or other geometric shape, the injection plunger 91 is axially slidably disposed through the shaft hole 83 of the screw 80 by the rod 911, the rod 911 is fixed through the central hole 73 of the one-way ratchet 70, wherein a positioning block 913 is formed on the rod 911 to fix the one-way ratchet 70 on the rod 911, the rod 911 of the injection plunger 91 has a rear end of the pressing end 912 extending out of the inner spiral conduit 52, the push rod end cap 92 is sleeved outside the pressing end 912 of the injection push rod 91, and the pivot part at the rear end of the inner spiral duct 52 is pivoted in the push rod end cap 92.

As shown in fig. 3 and 6, when the medicine bottle 2 is assembled, in a state where the medicine bottle cover 30 is detached, one end of the medicine bottle 2 having the piston 2A is inserted into the engaging collar 20 and positioned, the piston top block 84 at the side end of the screw rod 80 is inserted into the medicine bottle 2 and abuts against the piston 2A, the medicine bottle cover 30 is fitted to the outside of the medicine bottle 2, and the medicine bottle 2 is fixed to the injector 1 by the engagement of the medicine bottle cover 30 and the engaging collar 20. When the injection is not performed, the pen cap 5 is first sleeved on the outer side of the medicine bottle housing 30 in a state that the needle 3 and the needle cap 4 are not assembled on the medicine bottle housing 30 to assemble the medicine bottle 2.

When preparing injection, as shown in fig. 3 and 7, the pen cap 5 is removed, the needle 3 and the needle cap 4 are installed, one end of the needle 3 is inserted into the medicine bottle 2, and the needle cap 4 covers the outside of the needle 3, so as to prevent the user from being pricked by the needle 3 by mistake. Then, the injection push rod set 90 is pulled back along the axial direction to a predetermined position until the spiral guide block 521 on the outer circumferential surface of the inner spiral conduit 52 moves to contact the position limiting stop edge 43 at the rear end of the inner sleeve 40 and is clamped and stopped. In the process of pulling the injection push rod group 90 backward, the inner spiral conduit 52 is driven to move backward and idle inside the outer spiral conduit 51, the non-return key 42 at the rear end of the inner sleeve 40 can bounce at the non-return annular thread 522 of the inner spiral conduit 52 to generate sound, and the non-return key 42 at the rear end of the inner sleeve 40 abuts against the non-return annular thread 522 of the inner spiral conduit 52 for limiting, so that the function of preventing the injection push rod group 90 from being pressed mistakenly to drive the inner spiral conduit 52 to move forward and axially and linearly is generated, and the injection push rod group 90 cannot be pressed mistakenly to retract in the process of pulling the injection push rod group 90 backward.

During injection, as shown in fig. 8 and 9, the needle cover is pulled off to pierce the needle 3 into a predetermined injection site of a human body, and the injection plunger assembly 90 is pressed to start injection, wherein the inner spiral duct 52 is pushed by the plunger end cover 92 through the action of pressing the injection plunger assembly 90 straight forward, wherein the check key 42 at the rear end of the inner cannula 40 enters the axial guide slot 523 of the inner spiral duct 52 to allow the inner spiral duct 52 to move straight forward together with the injection plunger assembly 90, and the outer spiral duct 51 is driven by the spiral guide block 521 on the outer circumferential surface of the inner spiral duct 52 to rotate forward at a fixed point until the inner spiral duct 52 finishes a travel distance from the outer spiral duct 51, the injection plunger assembly 90 extends into the outer housing 10 to be closed, the outer spiral duct 51 rotates forward to drive the screw ring 60 to rotate together with the screw rod 80, and the screw ring 60 rotates to drive the screw rod 80 to rotate forward to apply a thrust to the piston 2A in the medicine bottle 2, the medicine in the medicine bottle 2 is discharged through the needle 3.

In the above, the screw guide groove 514 of the predetermined distance inside the outer screw conduit 51 is engaged with the screw guide block 521 on the outer circumferential surface of the inner screw conduit 52, and the screw ring 60 installed in the outer screw conduit 51 is engaged with the screw rod 80, so that the injection push rod set 90 can be pushed only by the predetermined distance once, and the screw ring 60 is driven to drive the screw rod 80 to rotate one revolution, and then stop, thereby controlling the medicament bottle 2 to output the set injection dose. On the other hand, the combined structure of the screw guide groove 514 of the outer screw conduit 51 and the screw guide block 521 of the inner screw conduit 52 and the combined structure of the screw hole of the screw ring 60 and the screw thread of the screw push rod 80 are combined to form a combined structure of a small screw pitch stroke, so that the large stroke rotational thrust is converted into a small stroke rotational injection thrust, and the injector 1 has the effect of saving labor in the using process.

After the injection is finished, the needle head cover 4 is sleeved outside the needle head 3, then the needle head 3 and the needle head cover 4 are pulled out from the injector 1 together, and the pen cap 5 is covered outside the medicine bottle sleeve shell 30 of the injector 1, so that the next use is ensured, and the new needle head 3 can be replaced for use. When the injector 1 is used, the injection push rod set 90 is combined with the interlocking mechanism of the one-way ratchet wheel 70, the two-way spiral guide tube set 50, the screw connection ring 60 and the spiral push rod 80, so that the injector can be operated and used conveniently by a user in a circulating opening and closing mode in the operation process of each quantitative injection. The number of times of injection and the dose of injection are set according to the volume of the medicine in the medicine bottle 2 by the number of turns of the thread and the pitch of the outer peripheral surface of the dose control section 81 of the screw rod 80, so that the injector 1 has the functions of fixed dose injection and automatic counting. When the injector 1 with the medicine bottle 2 is used for a predetermined number of times, the medicine in the medicine bottle 2 is just used up, and at this time, the injector 1 is discarded, so that the injector 1 is prevented from being used excessively.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (6)

1. A syringe for use with a vial and a needle, the syringe comprising:

the outer protecting shell is a hollow body with openings formed at the front end and the rear end;

the joint lantern ring is assembled at the front end of the outer casing, an inner ring part is arranged in the joint lantern ring, and a unidirectional ratchet groove with a plurality of single inclined ratchets is formed in the inner ring part;

a vial housing assembled to the front end of the engagement collar for holding the vial therein, the needle being detachably assembled to the front end of the vial housing;

the inner sleeve is arranged in the outer casing, and the front end of the inner sleeve is fixed in the joint sleeve ring;

a bidirectional spiral guide pipe group which comprises an outer spiral guide pipe and an inner spiral guide pipe, wherein the outer spiral guide pipe is arranged in the inner sleeve, the external spiral conduit comprises a spiral pipe part and a pipe end formed at the front end of the spiral pipe part, the inner peripheral wall of the spiral pipe part forms a spiral guide groove, the outer peripheral surface of the pipe end forms a plurality of single inclined ratchet elastic pieces, the ratchet spring pieces are respectively abutted against the single inclined ratchets of the one-way ratchet tooth groove of the joint lantern ring, so that the outer spiral catheter can only rotate in one direction, the inner spiral conduit is arranged in the inner sleeve and the outer spiral conduit, the outer peripheral surface of the front section of the inner spiral conduit is provided with a plurality of spiral guide blocks, the spiral guide block is arranged in the spiral guide groove of the outer spiral conduit to ensure that the inner spiral conduit can rotate and advance in the outer spiral conduit, a unidirectional ratchet groove with a plurality of single inclined ratchets is formed in the rear section of the inner spiral conduit;

the screw connection ring is assembled and positioned in the pipe end of the external spiral conduit, and a screw hole is formed in the screw connection ring;

the unidirectional ratchet wheel is arranged in the unidirectional ratchet tooth groove of the inner spiral conduit and comprises a wheel body and a plurality of single oblique ratchet elastic pieces formed on the peripheral surface of the wheel body, a middle hole is formed in the wheel body, and the single oblique ratchet elastic pieces are meshed with single oblique ratchets in the unidirectional ratchet tooth groove;

the spiral push rod comprises a dose control section, threads are arranged on the peripheral surface of the dose control section, a shaft hole is formed in the spiral push rod, the spiral push rod is arranged in the bidirectional spiral guide pipe group, and the dose control section of the spiral push rod is in threaded connection with the inside of the threaded connection ring and used for extending into the medicament bottle to apply thrust; and

an injection push rod group, it contains an injection push rod and a push rod end cover, the injection push rod contains a body of rod and one locates the tip of pressing of body of rod rear end, the injection push rod the body of rod pass the rigid coupling in one-way ratchet in the mesopore, just the body of rod is worn to locate with axially sliding in the screw rod in the shaft hole, the injection push rod the body of rod rear end reaches press the tip to be located outside the interior spiral pipe, push rod end cover is located the injection push rod press the tip outside, interior spiral pipe rear end pivot is located in the push rod end cover, make injection push rod group combine one-way ratchet two-way spiral guide nest of tubes the screw ring with screw rod can circulate the switching action.

2. The syringe of claim 1, wherein the rear end of the inner sleeve forms a check key and a limit stop edge, the outer peripheral surface of the rear section of the inner spiral conduit forms a plurality of check annular threads and is provided with an axial guide groove, the check key can be stopped at the check annular threads of the inner spiral conduit to prevent the inner spiral conduit from moving forward, the check key is converted to the axial guide groove to enable the inner spiral conduit to be driven to move forward, and the limit stop edge limits the position of the inner spiral conduit moving backward.

3. The injector of claim 1 or 2, wherein the axial bore of the helical ram and the stem of the injection ram are correspondingly non-circular in shape.

4. The syringe of claim 1 or 2, wherein the threaded ring has an axially extending positioning protrusion formed on an outer peripheral surface thereof, and a positioning recess formed on an inner wall of the tube end of the outer spiral conduit, and the threaded ring is positioned in the tube end of the outer spiral conduit by engagement of the corresponding positioning protrusion and positioning recess.

5. The syringe of claim 4, wherein the front and rear ends of the engagement collar are respectively an engagement ring portion and a set of engagement ring portions, the engagement ring portions are disposed and assembled in the outer casing, the engagement collar has a plurality of hooks between the inner ring portion and the engagement ring portion, and the engagement collar has an inner ring disposed between the engagement ring portion and the inner ring portion; the front end of the inner sleeve extending into the joint lantern ring is provided with a clamping groove, the clamping groove is used for clamping the clamping hook of the joint lantern ring correspondingly, the inner ring is sleeved outside the clamping hook, and the inner sleeve is fixedly connected with the joint lantern ring.

6. The syringe of claim 5 wherein the forward end of the dose control section of the helical ram houses a plunger tip.