Automatic injection device

Abstract

The present invention provides an automatic injection device, including a housing, a push rod, a push rod driving assembly and a spring force assembly; the housing includes a containing housing, a supporting housing and a pressing cover, the syringe is arranged in the containing housing, the supporting housing is connected to the containing housing, and the pressing cover is located on the supporting housing; the working end of the push rod can be extended into the containing housing, the driving end of the push rod is arranged in the supporting housing and is driven by the pressing cover; the push rod driving assembly includes a rotating body, a spiral guide cylinder, an inner rotating cylinder, and an outer rotating cylinder; the spring force assembly includes a force spring and a return spring for providing a driving force. The present invention realizes the extension of the push rod driven by the force by changing the positional relationship between the outer rotating cylinder and the rotating body, and finally realizes the quantitative injection of the medicine. The whole injection process is completed with one key, making the injection process easier, and the whole injection process has good stability and high accuracy of the injection dose.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices, and in particular relates to an automatic injection device. Background Art

[0002] The known injection devices have the following disadvantages in use: 1. The dose setting assembly of the known injection devices is to manually rotate the dose display barrel. The dose display barrel is connected to the injection device housing by a large pitch thread. The scales are evenly arranged on the spiral line. The scales are used as a reference for setting the precise injection dose. When setting the current injection dose, the dose display barrel needs to be rotated clockwise. At this time, the dose display barrel will be exposed on the outside of the injection device due to the spiral motion. During injection, it is necessary to continuously press the release button exposed on the dose display barrel to return the dose display barrel to the inside of the syringe and apply force to the drive assembly for injecting the set dose. This injection method requires the patient to continuously press and exert force with his thumb during injection, which is prone to uneven force causing the injection device to tilt or shake in the injection direction, thereby increasing the patient's pain during injection, and also diverting the patient's attention during injection, resulting in a poor injection experience. Second, the traditional injection device does not have a remaining dose memory function. When the medicine in the container is about to be injected for the last time, the set injection dose will be greater than the remaining injectable dose in the container. The patient will subjectively believe that the injection dose has reached the requirement, but in fact the set dose is not injected, which will cause the injection effect to fail. More seriously, such as insulin injection, a reduction in dose will cause the patient's blood sugar to rise, affecting the patient's life safety. Summary of the invention

[0003] In view of the defects of the prior art, the present invention provides an automatic injection device, which can realize the automatic operation of the injection process and is easy to use.

[0004] In order to achieve the above-mentioned object, the present invention provides an automatic injection device, comprising a housing, a push rod acting on the syringe, a push rod driving assembly and a spring force application assembly;

[0005] The housing comprises a containing housing, a supporting housing and a pressing cover, the syringe is arranged in the containing housing, the supporting housing is connected to the containing housing, and the pressing cover is located on the supporting housing;

[0006] The working end of the push rod is arranged in the accommodating shell so as to be extendable, and the driving end of the push rod is arranged in the supporting shell and is driven by applying force through the pressing cover;

[0007] The push rod driving assembly includes a rotating body, a spiral guide cylinder, an inner rotating cylinder, and an outer rotating cylinder;

[0008] The spiral guide cylinder is installed in the supporting shell, and the inner rotating cylinder is sleeved on the spiral guide cylinder and can slide on the spiral guide cylinder to change its position;

[0009] The outer drum is sleeved on the inner drum and can slide relative to the inner drum during synchronous rotation;

[0010] The rotating body is arranged in the supporting shell, and can be coupled with the outer rotating drum, and the rotating body is rotationally connected with the pushing rod, and the rotation of the rotating body is converted into the extension of the pushing rod;

[0011] The spring force application component includes a force application spring and a return spring;

[0012] The force spring is sleeved on the spiral guide cylinder, and the squeezed force spring drives the inner rotating cylinder to rotate on the spiral guide cylinder;

[0013] The return spring is arranged between the outer rotating drum and the pressing cover. Pressing the brake pressing cover can compress the return spring so that the outer rotating drum is axially separated from the supporting shell and slides to be coupled with the rotating body.

[0014] In the above technical solution of the present invention, the push rod directly acts on the movable stopper of the syringe, and the push rod is driven by the push rod driving assembly so that the push rod extends forward to a specified position, thereby injecting a specified dose of medicine.

[0015] Furthermore, the push rod drive assembly adopts a plurality of mutually nested cylindrical structures, wherein relative sliding can be performed during the synchronous rotation between the inner and outer rotating cylinders, thereby changing the matching relationship between the outer rotating cylinder and the rotating body, and finally realizing the matching connection between the outer rotating cylinder and the rotating body, so as to drive the push rod to extend through the rotating body to carry out the process of injection and drug administration.

[0016] Specifically, the present invention adopts a spring structure, in conjunction with a push rod driving assembly, to convert the linear force of the spring into the rotation of the inner rotating cylinder relative to the spiral guide cylinder. Through the cooperation between the inner rotating cylinder and the outer rotating cylinder, and between the outer rotating cylinder and the rotating body, the rotation is again converted into the linear feed of the push rod to obtain quantitative injection medication.

[0017] According to another specific embodiment of the present invention, it further includes a one-way retaining spring, and the driving end of the push rod is located in the spiral guide cylinder, wherein the one-way retaining spring is arranged on the driving end of the push rod and can slide unidirectionally in the spiral guide cylinder.

[0018] According to another specific embodiment of the present invention, the spiral guide cylinder is provided with a slot that cooperates with the one-way retaining spring, which is used to limit the maximum extension position of the push rod. When the one-way retaining spring slides to the slot, the one-way retaining spring is limited and cannot continue to slide. This position is the maximum extension position of the push rod.

[0019] According to another specific embodiment of the present invention, a guide strip is provided inside the spiral guide cylinder along its length direction, and a guide groove cooperating with the guide strip is provided on the push rod, thereby restricting the spiral guide cylinder from rotating, so as to make the structure more stable.

[0020] According to another specific embodiment of the present invention, the inner drum and the outer drum are arranged with the following structure to perform relative sliding during synchronous rotation:

[0021] The outer circumference of the inner drum is provided with a plurality of sliding blocks which are symmetrically distributed and axially staggered;

[0022] A sliding groove which matches the sliding block one by one is arranged in the outer rotating cylinder.

[0023] According to another specific embodiment of the present invention, it further comprises a screw directional ring, which is fixed on the housing, the screw directional ring is provided with a guide protrusion, and the push rod is provided with an open groove matching the guide protrusion.

[0024] According to another specific embodiment of the present invention, the rotating body and the outer drum are connected with each other by meshing teeth.

[0025] According to another specific embodiment of the present invention, it further comprises a dose control assembly, which comprises a dose knob and a one-way ratchet, the one-way ratchet is fixed to the support housing, and the dose knob is rotatably disposed on the one-way ratchet;

[0026] The one-way ratchet is in the shape of a cylinder, and one end of the outer rotating cylinder passes through the one-way ratchet and is clamped between the dosage knob;

[0027] The rotation of the dosage knob drives the outer drum to rotate synchronously, driving the inner drum to rotate around the spiral guide cylinder to compress the force spring, thereby obtaining the specified injection dose.

[0028] According to another specific embodiment of the present invention, the dose control assembly also includes a memory ring for limiting the number of rotations of the dose knob, the memory ring is rotatably arranged on the one-way ratchet, the dose knob is provided with a snap-fitting groove, and the memory ring is provided with a snap-fitting protrusion that cooperates with the snap-fitting groove.

[0029] According to another specific embodiment of the present invention, the inner drum is provided with a spiral dosage scale, and the support shell is provided with a window for displaying the dosage scale, wherein the outer drum is provided with a transparent structure or a hollow structure matching the window.

[0030] According to another specific embodiment of the present invention, the pitch of the helix of the dosage scale is consistent with the pitch of the helix of the spiral guide tube.

[0031] According to another specific embodiment of the present invention, it also includes a hidden needle assembly, which includes a hidden needle cap, a return spring, and a hidden needle sleeve;

[0032] The hidden needle cover is detachably connected to the accommodating shell, and is provided with a directional sliding groove along the length direction of the needle;

[0033] The hidden needle cap is provided with a directional slider, through which it is connected to the hidden needle sleeve;

[0034] The return spring is arranged in the hidden needle sleeve and abuts against the hidden needle sleeve and the hidden needle cap respectively;

[0035] Among them, a gasket that can directly contact the skin is provided on the working end surface of the hidden needle cap. The gasket can be made of skin-friendly materials such as silicone to facilitate use.

[0036] The present invention has the following beneficial effects:

[0037] The automatic injection device of the present invention adopts an inner rotating cylinder and an outer rotating cylinder that can rotate synchronously to realize the conversion of the force, and realizes the extension of the push rod driven by the force by changing the positional relationship between the outer rotating cylinder and the rotating body, thereby finally realizing the quantitative injection of the medicine. The whole injection process is completed with one button (pressing the cover), making the injection process easier, and the whole injection process has good stability and high accuracy of the injection dose.

[0038] In addition, when the present invention is in the non-use state, there is no contact between the outer rotating cylinder and the rotating body. At this time, by applying a force to the pressing cover, it will be converted into the use state. At this time, a coupling connection is established between the outer rotating cylinder and the rotating body. Under the action of the force spring, the inner rotating cylinder and the outer rotating cylinder are driven to rotate synchronously, thereby causing the rotating body to rotate, thereby achieving the purpose of driving the push rod to extend forward.

[0039] In addition, the present invention provides a one-way retaining spring to limit the forward extension of the push rod so that it can only slide in one direction, thereby stabilizing the sliding process of the push rod.

[0040] In addition, the present invention is also provided with a dosage control component, which is used to accurately control the dosage of a single injection. At the same time, it can memorize the remaining medicine and control the set injection dosage to be no greater than the actual remaining dosage in the syringe, so as to ensure the patient's medication effect and medication safety.

[0041] In addition, the present invention is also provided with a hidden needle assembly to hide the needle. On the one hand, it facilitates the injection process by sticking the working end surface of the hidden needle cap on the patient's injection site. On the other hand, it makes the needle, which is most likely to cause fear in people during the injection process, invisible, thereby reducing the patient's fear and making the injection experience better.

[0042] The present invention will be further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1It is a schematic diagram of the overall structure of the automatic injection device of the present invention;

[0044] Figure 2 yes Figure 1 A-A cross-sectional schematic diagram;

[0045] Figure 3 is an exploded schematic diagram of the automatic injection device of the present invention;

[0046] Figure 4 It is a schematic structural diagram of the front cover cap of the present invention;

[0047] Figure 5 It is a schematic diagram of the structure of the hidden needle assembly of the present invention;

[0048] Figure 6 yes Figure 5 Exploded diagram of

[0049] Figure 7 yes Figure 5 A schematic diagram of the structure of the middle hidden needle sleeve;

[0050] Figure 8 It is a schematic diagram of the structure of the accommodating shell of the present invention;

[0051] Fig. 9 It is a structural schematic diagram of the push rod of the present invention;

[0052] Fig.10 It is a structural schematic diagram of the one-way retaining spring of the present invention;

[0053] Fig.11 It is a structural schematic diagram of the rotary body and the screw directional ring of the present invention;

[0054] Fig.12 It is a schematic diagram of the coordination of the rotary body, the push rod and the screw directional ring of the present invention;

[0055] Fig.13 It is a structural schematic diagram of the spiral guide cylinder of the present invention;

[0056] Fig.14 yes Fig.13 A schematic diagram of the structure from another perspective;

[0057] Fig.15 It is a schematic diagram of the structure of the inner drum of the present invention;

[0058] Fig.16 yes Fig.15 A schematic diagram of the structure from another perspective;

[0059] Fig.17 It is a schematic diagram of the coordination of the inner rotating cylinder, the spiral guide cylinder and the force applying spring of the present invention;

[0060] Fig.18It is a structural schematic diagram of the outer drum of the present invention;

[0061] Fig.19 yes Fig.18 A cross-sectional schematic diagram of

[0062] Fig. 20 It is a structural schematic diagram of the support shell of the present invention;

[0063] Fig.21 is a schematic diagram of the structure of the dosage control assembly of the present invention;

[0064] Fig. 22 yes Fig.21 The structural diagram of the one-way ratchet in the middle;

[0065] Fig.23 yes Fig.21 Schematic diagram of the structure of the medium dose knob. DETAILED DESCRIPTION

[0066] An automatic injection device for administering a drug by injection, such as Figure 1 -23, including a housing 100, a syringe portion 200, a push rod 300, a push rod drive assembly 400, a spring force assembly 500, a dose control assembly 600 and a hidden needle assembly 700.

[0067] See also Figure 1 , Figure 2 The automatic injection device of this example is in a pen-like structure as a whole, that is, an injection pen. The housing 100 includes a accommodating housing 110 at the front end, a front cap 120 that can be removed from the accommodating housing 110, a supporting housing 130 at the rear end, and a pressing cover 140 for the user to perform injection operations.

[0068] The syringe part 200 is disposed in the housing 110, see Figure 3 The syringe part 200 in this example includes a needle 210, a cartridge bottle 220, and a movable rubber plug 230, wherein the cartridge bottle 220 is placed in the accommodating shell 110, and the movable rubber plug 230 is located at the rear end of the cartridge bottle 220. The liquid medicine in the cartridge bottle 220 can be injected by pushing the movable rubber plug 230.

[0069] The middle portion of the accommodating shell 110 in this example is hollowed out and used as an observation port 111 for observing the remaining medicine in the cartridge bottle 220 .

[0070] The front end of the accommodating shell 110 in this example is provided with a threaded portion 112 for connecting to the needle 210. The needle 210 is connected to the threaded portion 112 to facilitate the removal of the needle and the assembly of a new needle. A small needle cap 240 is provided on the needle 210. During assembly, the small needle cap 240 does not need to be removed to prevent accidental injury to the patient when installing the needle 210.

[0071] The working end of the push rod 300 is planar and can be extended into the accommodating shell 110 to directly act on the movable rubber plug 230 to perform an injection operation. It is driven by the push rod driving assembly 400 and the spring force assembly 500.

[0072] See also Figure 3 , Fig.10 - Fig.19 , the push rod driving assembly 400 includes a rotating body 410, a spiral guide cylinder 420, an inner rotating cylinder 430, and an outer rotating cylinder 440;

[0073] The spiral guide cylinder 420 is installed in the support housing 130, and the inner rotating cylinder 430 is sleeved on the spiral guide cylinder 420 and can slide (rotate in a spiral form) on the spiral guide cylinder 420 to change its position;

[0074] The outer drum 440 is sleeved on the inner drum 430, and can slide relatively during the synchronous rotation with the inner drum 430. The connection between the two is preferably:

[0075] A plurality of symmetrically distributed and axially staggered sliders 431 are arranged on the outer circumference of the inner rotating cylinder 430, for example, four sliders 431 are arranged, and a slide groove 441 which matches the slider 431 one by one is arranged in the outer rotating cylinder 440, wherein the slide groove 441 has a sufficient length to meet the relative sliding distance between the inner rotating cylinder 430 and the outer rotating cylinder 440.

[0076] Specifically, the outer drum 440 and the inner drum 430 can rotate synchronously but can slide freely in the axial direction. Any driving of either of them can make them rotate synchronously, that is, the inner drum 430 will make a spiral motion on the spiral guide drum 420 .

[0077] The rotating body 410 is disposed in the supporting shell 130, and can be coupled to the outer rotating cylinder 440. The rotating body 410 is rotationally connected to the push rod 300, and the rotation of the rotating body 410 is converted into the extension of the push rod 300.

[0078] The front end of the spiral guide cylinder 420 is in direct contact with the rotating body 410, and the spiral guide cylinder 420 does not rotate. In order to reduce the rotational friction between it and the rotating body 410, a conical abutment boss 421 is provided at the front end of the spiral guide cylinder 420. The abutment boss 421 has a smaller contact area, which can reduce the friction force generated by the relative rotation between the two.

[0079] Furthermore, a circular connecting cylinder 411 capable of extending into the spiral guide cylinder 420 is provided on the rotating body 410 to improve the relative rotation ability between the rotating body 410 and the spiral guide cylinder 420 .

[0080] Specifically, the circular connecting cylinder 411 is provided with a circular / semi-circular folded edge 412, and a semi-circular groove 422 is provided on the inner surface of the front end of the spiral guide cylinder 420 for loosely fitting with the folded edge 412 so that the two can rotate relative to each other but cannot be separated in the axial direction.

[0081] A sleeve structure 450 may be provided at the position where the inner drum 430 contacts the rotating body 410, so as to make the relative rotation process between the two more stable.

[0082] The spring force-applying assembly 500 includes a force-applying spring 510 and a return spring 520 . The force-applying spring 510 is sleeved on the spiral guide cylinder 420 . The squeezed force-applying spring 510 drives the inner rotating cylinder 430 to rotate on the spiral guide cylinder 420 . The squeezing force of the force-applying spring 510 comes from the rotational squeezing of the inner rotating cylinder 430 .

[0083] Specifically, one end of the force spring 510 abuts against the inner rotating cylinder 430, and the other end of the force spring 510 abuts against the spiral guide cylinder 420, see Fig.17 Preferably, a round table 423 is provided at the rear end of the spiral guide cylinder 420, and a first turntable 460 for abutment is sleeved on the spiral guide cylinder 420, and one end of the force spring 510 abuts against the inner rotating cylinder 430 through the first turntable 460, wherein a conical abutment boss is also provided at a position on the first turntable 460 that contacts the inner rotating cylinder 430 to reduce the friction force formed by the relative rotation between it and the inner rotating cylinder 430.

[0084] The return spring 520 is arranged between the outer rotating cylinder 440 and the pressing cover 140. Pressing the brake pressing cover 140 can compress the return spring 520. The compressed return spring 520 provides sufficient force to make the outer rotating cylinder 440 axially disengaged from the supporting shell 130 and slide to couple with the rotating body 410.

[0085] When the outer drum 440 is separated from the supporting shell 130, it loses its rotation constraint. At this time, under the action of the force spring 510, the outer drum 440 and the inner drum 430 form the rotation of the inner drum 430 relative to the spiral guide drum 420, thereby driving the synchronous rotation of the outer drum 440.

[0086] Under the action of the return spring 520, the outer rotating cylinder 440 slides to couple with the rotating body 410. Specifically, the coupling connection between the two preferably adopts a meshing tooth 470 connection structure to achieve a normal meshing process under multiple rotation positions. At this time, the rotational motion of the outer rotating cylinder 440 is transmitted to the rotating body 410, driving the rotating body 410 to rotate, and then driving the push rod 300 that is rotationally connected to the rotating body 410 (specifically, for example, a threaded or spiral connection) to extend forward to complete the injection.

[0087] When the force of the force spring 510 is eliminated, the push rod 300 will no longer extend forward, and the single injection medication process ends.

[0088] In this example, in order to stabilize the injection process in which the push rod 300 extends forward, a screw orienting ring 480 is provided. The screw orienting ring 480 is fixedly mounted on the shell 100, specifically, for example, it is clamped at the end position of the accommodating shell 110 through a positioning protrusion 481, wherein an inner circular boss 482 is provided on the inner circle of the screw orienting ring 480, and a rectangular groove 310 matching the inner circular boss 482 is provided on the push rod 300 to prevent the push rod 300 from rotating during the advancement process.

[0089] A compression spring 483 may also be provided between the screw positioning ring 480 and the rotating body 410 .

[0090] Furthermore, a guide strip 424 is also provided on the inner wall of the spiral guide cylinder 420 along its length direction, and a guide groove cooperating with the guide strip 424 is provided on the push rod 300, thereby restricting the spiral guide cylinder 420 from rotating, so as to make the structure more stable.

[0091] The guide groove may also be a rectangular groove 310 to simplify the structure.

[0092] In this example, in order to ensure the one-way sliding effect of the push rod 300, a one-way snap spring 490 is further provided. A preferred structure of the one-way snap spring 490 is as follows: Fig.10 As shown, two square grooves 491 are provided in the middle of the one-way retaining spring 490 for engaging with two symmetrical bosses 320 provided at the driving end (rear end) of the push rod 300 to limit the position of the one-way retaining spring 490 .

[0093] Specifically, a bending portion 492 is provided at the front end of the one-way retaining spring 490, and the bending portion 492 forms an angle pointing to the rear end so that it has elastic deformation ability in the radial direction to achieve its ability to move forward in one direction, wherein the bending portion 492 limits the possibility of its movement toward the rear end.

[0094] Preferably, the end of the bending portion 492 is configured to be in an arc shape, so that the resistance to sliding in the spiral guide cylinder 420 is greatly reduced.

[0095] Furthermore, the spiral guide cylinder 420 is provided with a slot 425 that cooperates with the one-way retaining spring 490, which is used to limit the maximum extension position of the push rod 300. When the one-way retaining spring 490 slides to the slot 425, the bent portion 492 on the one-way retaining spring 490 extends out of the slot 425 and is limited and cannot continue to slide. At the same time, a locking groove 433 is provided on the inner wall of the inner rotating cylinder 430, and the bent portion 492 extending from the slot 425 is locked in the locking groove 433.

[0096] This position is the maximum extension position of the push rod 300. At this time, the push rod 300 cannot move further, so as to inform the patient that the injection has been completed.

[0097] See also Figure 3 , Fig. 20 - Fig.23 The dose control component 600 is used to set a dose for a single injection, wherein the set dose is adjustable and is always no greater than the actual dose of the remaining drug in the cartridge bottle. A preferred dose control component 600 includes a dose knob 610, a one-way ratchet 620, and a memory ring 630.

[0098] The one-way ratchet 620 is cylindrical and is installed at the rear end of the support shell 130, for example, by a snap-fitting manner. The dose knob 610 is rotatably arranged on the one-way ratchet 620, wherein the rear end of the outer rotating cylinder 440 passes through the one-way ratchet 620 and is snap-fitted / plug-fitted with the dose knob 610, and the pressing cover 140 and the outer rotating cylinder 440 are connected together in a snap-fitting manner, wherein the pressing cover 140 and the outer rotating cylinder can not only slide back and forth synchronously, but also rotate relative to each other.

[0099] The return spring 520 is disposed between the dosage knob 610 and the push cover 140 to achieve axial separation of the push cover 140 and the outer drum 440 .

[0100] In this example, a second turntable 640 may be provided between the pressing cover 140 and the outer rotating cylinder 440 . The second turntable 640 is preferably made of self-lubricating POM material to maintain smoothness between the two so that the pressing cover 140 and the outer rotating cylinder 440 can rotate freely in the radial direction.

[0101] The snap-fitting mode between the dosage knob 610 and the outer drum 440 is preferably:

[0102] The outer rotating cylinder 440 is in a stepped cylindrical shape, and a splicing tooth 442 is provided along its axial direction on the outer periphery of the rear end of the outer rotating cylinder 440 , and a splicing groove 611 is provided on the inner circumferential wall of the dose knob 610 . The splicing tooth 442 disposed in the splicing groove 611 can drive the outer rotating cylinder 440 and the dose knob 610 to rotate synchronously.

[0103] The rotation of the dosage knob 610 drives the outer drum 440 to rotate synchronously, and drives the inner drum 430 to rotate around the spiral guide drum 420 to compress the force spring 510, so that the force spring 510 obtains a certain compression stroke, thereby obtaining a specified injection dose.

[0104] The memory ring 630 is used to limit the number of rotations of the dose knob 610, and is threadedly connected to the one-way ratchet 620, wherein the dose knob 610 is provided with a snap-fit ​​groove 612, and the memory ring 630 is provided with a snap-fit ​​protrusion 631 that matches the snap-fit ​​groove 612. On the one hand, the memory ring 630 rotates synchronously with the dose knob 610, and on the other hand, it limits the maximum number of rotations of the dose knob 610 to ensure that the set dose is always no greater than the actual dose of the remaining medicine in the cartridge bottle.

[0105] Specifically, the dose knob 610 in this example does not rotate and feed itself, but changes the position of the memory ring 630 on the one-way ratchet 620 through the sliding fit with the memory ring 630 to achieve the effect of limiting the maximum number of rotations of the dose knob 610.

[0106] In this example, the set injection dose can also be directly displayed in an intuitive way. The specific structure is as follows:

[0107] The inner drum 430 is provided with a spiral dosage scale 432, and the support shell 130 is provided with a window 131 for displaying the dosage scale 432, wherein the outer drum 440 is provided with a transparent structure matching the window or is made of a transparent material as a whole.

[0108] Furthermore, the helical pitch of the dosage scale 432 is consistent with the helical pitch of the spiral guide cylinder 420 , so that when the inner cylinder 430 and the outer cylinder 440 rotate relative to each other, the corresponding scale is always accurately displayed on the viewing window 131 .

[0109] In this example, the one-way ratchet 620 can simultaneously realize the retention of the dosage scale 432, wherein the inner circumferential surface of the dosage knob 610 is provided with ratchet teeth 613, and the rear end of the one-way ratchet 620 is provided with a pawl 621. After the two cooperate, they can perform one-way intermittent motion and have a self-locking characteristic, and at the same time transmit the intermittent and locking characteristics to the outer rotating drum 440 and the inner rotating drum 430, so that the inner rotating drum 430 also has the functions of gap motion and locking, thereby realizing the functions of intermittent jumping and locking retention of the dosage scale 432.

[0110] See also Figure 3 , Figure 5 - Figure 8 The hidden needle assembly 700 is used to provide a needle hiding function, and includes a hidden needle cap 710 , a return spring 720 and a hidden needle cover 730 .

[0111] The hidden needle cover 730 is detachably connected to the housing 110, and is provided with four directional slide grooves 732 along the length direction of the needle. The hidden needle cap 710 is provided with a directional slider 712 corresponding to the directional slide grooves 732. The hidden needle cap 710 is connected to the hidden needle cover 730 through the directional slider 712, and the hidden needle cap 710 can slide along the length direction of the needle, wherein the four directional slide grooves 732 are distributed in an interval manner;

[0112] The return spring 720 is disposed in the hidden needle sleeve 730 and abuts against the hidden needle sleeve 730 and the hidden needle cap 710 respectively;

[0113] A preferred connection method between the hidden needle sleeve 730 and the accommodating housing 110 is:

[0114] Two centrally symmetrical connecting bosses 731 are arranged on the inner circular surface of the hidden needle sleeve 730, and two L-shaped opening grooves 113 are arranged on the accommodating shell 110. The connecting bosses 731 can first slide in the axial direction along the trajectory of the L-shaped opening groove 113, and then convert into radial rotational motion at the corner position, and finally rotate to the end position of the L-shaped opening groove 113 to complete the connection.

[0115] Furthermore, during the radial rotational movement at the corner position, a matching boss 114 may be provided in the L-shaped opening groove 113 to form a slight interference with the connecting boss 731, thereby forming a slight sense of frustration, reminding the patient that the hidden needle sleeve 730 has been installed in place.

[0116] In this example, a gasket 711 capable of directly contacting the skin is provided on the working end surface of the hidden needle cap 710. The gasket 711 can be made of a skin-friendly material such as silicone to facilitate use.

[0117] In this example, before injection, under the action of the return spring 720, the hidden needle cap 710 extends out of the hidden needle cover 730 to cover the needle for hiding the needle. During the injection process, the gasket 711 on the working end surface of the hidden needle cap 710 is close to the injection site of the patient, and the housing 100 (support housing 130 or accommodating housing 110) is pressed to shrink the return spring 720, and the needle is inserted into the subcutaneous tissue, making the needle invisible during the needle insertion process. After the injection is completed, the patient pulls out the needle, and the hidden needle cap 710 pops out under the action of the return spring 720, making the needle invisible during the needle removal process.

[0118] like Figure 4 As shown, the front cover cap 120 in this example is a cylindrical cap-shaped thin-walled part, which is used to protect the fluid container from being exposed and to avoid contamination. A pen clip boss 121 is provided on the outer circumferential surface of the front cover cap 120, and the local clamping force is greater for easy carrying.

[0119] In this example, a snap-fit ​​structure may be used to connect the accommodating shell 110 and the supporting shell 130 to facilitate the manufacturing process.

[0120] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the scope of the present invention. Any person skilled in the art can make some improvements without departing from the scope of the present invention, that is, all equivalent improvements made according to the present invention should be covered by the scope of the present invention.

Claims

1. An automatic injection device, characterized in that: It includes a housing, a push rod acting on the syringe, a push rod driving assembly and a spring force application assembly; The housing comprises a containing housing, a supporting housing and a pressing cover, the syringe is arranged in the containing housing, the supporting housing is connected to the containing housing, and the pressing cover is located on the supporting housing; The working end of the push rod is arranged in the accommodating shell so as to be extendable, and the driving end of the push rod is arranged in the supporting shell and is driven by the pressing cover; The push rod driving assembly comprises a rotating body, a spiral guide cylinder, an inner rotating cylinder and an outer rotating cylinder; The spiral guide cylinder is installed in the support shell, and the inner rotating cylinder is sleeved on the spiral guide cylinder and can slide on the spiral guide cylinder to change its position; The outer drum is sleeved on the inner drum and can slide relatively with the inner drum during synchronous rotation; The rotating body is arranged in the supporting shell, and can be coupled to the outer rotating cylinder, and the rotating body is rotationally connected to the pushing rod, and the rotation of the rotating body is converted into the extension of the pushing rod; The spring force application component comprises a force application spring and a return spring; The force spring is sleeved on the spiral guide cylinder, and the squeezed force spring drives the inner rotating cylinder to rotate on the spiral guide cylinder; The return spring is arranged between the outer rotating cylinder and the pressing cover. Pressing and braking the pressing cover can compress the return spring, so that the outer rotating cylinder is axially disengaged from the supporting shell and slides to be coupled with the rotating body.

2. The automatic injection device according to claim 1, characterized in that: It further comprises a one-way retaining spring, wherein the driving end of the push rod is located in the spiral guide cylinder, wherein the one-way retaining spring is arranged on the driving end of the push rod and can slide one-way in the spiral guide cylinder.

3. The automatic injection device according to claim 2, characterized in that: The spiral guide cylinder is provided with a notch matched with the one-way retaining spring, which is used to limit the maximum extension position of the push rod.

4. The automatic injection device according to claim 1, characterized in that: A guide strip is arranged inside the spiral guide cylinder along its length direction, and a guide groove matching with the guide strip is arranged on the push rod.

5. The automatic injection device according to claim 1, characterized in that: The inner drum and the outer drum are arranged with the following structure to perform relative sliding during synchronous rotation: The outer circumference of the inner drum is provided with a plurality of sliding blocks which are symmetrically distributed and axially staggered; The outer rotating cylinder is provided with a sliding groove which matches with the sliding block one by one.

6. The automatic injection device according to claim 1, characterized in that: It further comprises a screw rod orientation ring which is fixed on the housing, the screw rod orientation ring is provided with a guide protrusion, and the push rod is provided with an open groove which matches with the guide protrusion.

7. The automatic injection device according to claim 1, characterized in that: Further comprising a dose control assembly, comprising a dose knob and a one-way ratchet, wherein the one-way ratchet is fixed to the support housing, and the dose knob is rotatably disposed on the one-way ratchet; The one-way ratchet is in the shape of a cylinder, and one end of the outer rotating cylinder passes through the one-way ratchet and is engaged with the dosage knob; The rotation of the dosage knob drives the outer drum to rotate synchronously, and drives the inner drum to rotate around the spiral guide cylinder to compress the force spring, thereby obtaining a specified injection dose.

8. The automatic injection device according to claim 7, characterized in that: The dose control assembly further comprises a memory ring for limiting the number of rotations of the dose knob, the memory ring is rotatably arranged on the one-way ratchet, the dose knob is provided with a snap-fitting groove, and the memory ring is provided with a snap-fitting protrusion matched with the snap-fitting groove.

9. The automatic injection device according to claim 7, characterized in that: The inner drum is provided with a spiral dosage scale, and the support shell is provided with a window for displaying the dosage scale, wherein the outer drum is provided with a transparent structure or a hollow structure matching the window.

10. The automatic injection device according to claim 1, wherein: Also included is a hidden needle assembly, which includes a hidden needle cap, a return spring, and a hidden needle sleeve; The hidden needle cover is detachably connected to the accommodating shell, and is provided with a directional sliding groove along the length direction of the needle; The hidden needle cap is provided with a directional slider, and is connected to the hidden needle sleeve through the directional slider; The return spring is arranged in the hidden needle sleeve and abuts against the hidden needle sleeve and the hidden needle cap respectively; Wherein, a gasket capable of directly contacting the skin is provided on the working end surface of the hidden needle cap.

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