Forward and reverse rotation adjusting mechanism for syringe, injection pen
The design of a single gear mechanism simplifies the forward and reverse adjustment of the syringe, solves the problems of complex structure and large space occupation, and improves the accuracy and portability of dosage adjustment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU WANHAI MEDICAL INSTR CO LTD
- Filing Date
- 2025-06-11
- Publication Date
- 2026-06-12
AI Technical Summary
The existing syringe's forward and reverse adjustment mechanism is complex, requiring multiple sets of ratchet structures, which takes up a lot of space and affects portability and dosage accuracy.
A single gear mechanism is used, which achieves forward and reverse adjustment through the cooperation of the rotary drum gear, the upper gear of the rotary drum and the dosage knob, simplifying the structure and reducing the number of parts.
It significantly simplifies the internal structure of the syringe, reduces the number of parts, compresses the internal space occupied by the pen body, and improves the accuracy of dosage adjustment and portability.
Smart Images
Figure CN224345247U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of syringe technology, and particularly relates to a forward and reverse adjustment mechanism for syringes and an injection pen. Background Technology
[0002] In related technologies, Chinese patent application CN201324413Y discloses a quantitative adjustable pen syringe, including a fixed tube, a pusher, a sleeve, a clutch sleeve, rotating teeth, a screw, a transmission tube, a stop ring, a fixed ring, a rotating tube, a central rotating toothed cylinder, a transmission toothed cylinder, and a sleeve. It adjusts the pre-pressure dose during injection by rotating the end of the rotating tube to adjust its position relative to the sleeve. During the process of pressing the rotating tube inward, the rotating tube drives the central rotating toothed cylinder, the transmission toothed cylinder, the transmission tube, the rotating teeth, and the screw to rotate, thereby causing the screw to advance forward relative to the sleeve and inject the needle placed in the fixed tube into the human body in a quantitative manner. It has an internal anti-reverse mechanism, so that even if the rotating tube is adjusted backward during the next injection, the pusher will not retract.
[0003] The aforementioned adjustable-quantity pen syringe actually rotates by rotating the tube, which drives the central gear cylinder, transmission gear cylinder, transmission tube, rotating gear, and screw to rotate, thereby propelling the screw forward relative to the socket. However, this adjustable-quantity pen syringe requires multiple sets of ratchet structures to achieve forward and reverse rotation, resulting in a complex structure. Furthermore, this structure leads to a large volume of forward and reverse adjustment mechanisms, requiring a larger internal space within the syringe.
[0004] Therefore, how to solve the above-mentioned defects is a technical problem that urgently needs to be solved in this field.
[0005] It should be noted that the information disclosed in this background section is only for understanding the background technology of this application concept, and therefore, the above description is not considered to constitute information related to the technology. Utility Model Content
[0006] This disclosure provides at least one forward / reverse adjustment mechanism for a syringe and an injection pen.
[0007] In a first aspect, embodiments of this disclosure provide a forward / reverse adjustment mechanism for a syringe, comprising:
[0008] A rotating gear is fixed inside the pen body, and ratchet teeth are provided on the end wall of the rotating gear;
[0009] The dosage knob is located at the end of the pen body; the push rod cylinder is coaxially arranged with the cylinder gear and is adapted to move axially relative to the pen body;
[0010] The gear on the rotating drum is located inside the dosage knob, sleeved on the outer wall of the push rod rotating drum, and meshes with the rotating drum gear;
[0011] When the dosage knob is turned in the forward direction, the gear on the drive cylinder rotates in the forward direction relative to the cylinder gear, thereby driving the push rod cylinder to rotate and wind the coil spring inside the pen body.
[0012] When the dosage knob is turned in the reverse direction, the gear on the drum is pushed by the dosage knob to move away from the drum gear and disengage from the ratchet so that the gear on the drum rotates in the opposite direction relative to the drum gear.
[0013] In one optional embodiment, two annular spring pieces are provided on the peripheral wall of the gear on the rotating drum. One end of each annular spring piece extends circumferentially along the gear on the rotating drum in the same direction, and the other end of each annular spring piece extends obliquely toward the gear on the rotating drum and meshes with the corresponding ratchet.
[0014] When the dosage knob is rotated in the forward direction, the annular spring strikes each ratchet tooth in sequence to produce a sound.
[0015] In one optional embodiment, the inner wall of the dosage knob is provided with two push blocks, one push block corresponding to one annular spring, and the annular spring overlaps the corresponding push block;
[0016] When the dosage knob is rotated in the reverse direction, the pusher pushes the annular spring to elastically deform away from the rotary gear, causing the annular spring to disengage from the ratchet.
[0017] This causes the gear on the rotating drum to rotate in the opposite direction to the gear on the rotating drum.
[0018] In one alternative embodiment, the gear on the drum includes:
[0019] The main body is circular and is fitted onto the outer wall of the push rod cylinder;
[0020] The first flange, two first flanges are symmetrically arranged on the outer side wall of the body;
[0021] The second flange is symmetrically disposed on the outer side wall of the body and located between the two first flanges;
[0022] A groove is provided between the first flange sidewall and the second flange sidewall;
[0023] The annular spring extends circumferentially from the sidewall of the first flange along the body.
[0024] In one optional embodiment, the annular spring sheet includes a first spring sheet and a second spring sheet, wherein the first spring sheet is disposed on the side wall of the first flange, and the second spring sheet is disposed at the end of the first spring sheet and has an included angle relative to the first spring sheet;
[0025] The second segment of the spring meshes with the ratchet.
[0026] In one optional embodiment, a limiting disc is provided inside the dosage knob, the limiting disc is sleeved on the outer wall of the push rod rotating cylinder, and abuts against the side wall of the rotating cylinder gear away from the rotating cylinder gear;
[0027] The inner wall of the dosage knob is provided with two support blocks, which are located between the two push blocks, and the support blocks and the limiting plate are respectively located on both sides of the body.
[0028] In one optional embodiment, the inner wall of the dosage knob is further provided with two limiting blocks, the limiting blocks being located within the groove and adapted to slide within the groove;
[0029] When the dosage knob is rotated in the forward direction, the limiting block slides to abut against the second flange, thereby pushing the main body to rotate in the forward direction synchronously.
[0030] When the dosage knob is rotated in the reverse direction, the limiting block slides to the side of the first flange, and the push block first pushes the annular spring to deform elastically until it disengages from the ratchet. Then the limiting block abuts against the first flange to push the body to rotate in the reverse direction synchronously.
[0031] In one optional embodiment, a plurality of first toothed racks are evenly distributed circumferentially on the inner wall of the body;
[0032] A positioning ring is provided on the outer wall of the push rod rotary cylinder, and a plurality of second racks are symmetrically arranged on the outer wall of the positioning ring, the second racks meshing with the first rack.
[0033] In one optional embodiment, a coil spring bracket is provided on the side of the rotary gear away from the upper gear of the rotary drum, and the other end of the coil spring bracket is fixed to the end wall of the dial.
[0034] The coil spring is located inside the coil spring bracket, with the inner end of the coil spring fixed to the outer wall of the push rod cylinder and the outer end of the coil spring fixed to the inner wall of the coil spring bracket.
[0035] Secondly, this embodiment also provides an injection pen, which further includes a button disposed at the outer end of the plunger cylinder. The button is axially slidable relative to the dosage knob.
[0036] The beneficial effects of this invention are that it provides a forward / reverse adjustment mechanism for syringes. Through the cooperation of a rotating cylinder gear, an upper rotating cylinder gear, and a dosage knob, forward / reverse adjustment can be achieved with only a single gear mechanism. Compared to traditional syringes that rely on multiple ratchet structures for forward / reverse adjustment, this invention significantly simplifies the internal structure, reduces the number of parts, and compresses the internal space occupied by the syringe.
[0037] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention are realized and obtained through the structures particularly pointed out in the description and the accompanying drawings.
[0038] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description
[0039] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of this utility model, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0040] Figure 1 An unfolded perspective view of the forward and reverse rotation adjustment mechanism for a syringe provided in an embodiment of this disclosure;
[0041] Figure 2 A cross-sectional perspective view of the dosage knob provided in an embodiment of this disclosure;
[0042] Figure 3 A perspective view of the gear on the rotating drum provided in an embodiment of this disclosure;
[0043] Figure 4 A perspective view of the push rod state provided in an embodiment of this disclosure;
[0044] Figure 5 A cross-sectional view of a syringe forward / reverse adjustment mechanism provided in an embodiment of this disclosure;
[0045] Figure 6 An unfolded perspective view of the dosage knob and rotary gear provided in an embodiment of this disclosure.
[0046] In the picture:
[0047] 1. Pen body; 10. Button; 2. Rotary gear; 21. Spring support; 22. Ratchet;
[0048] 3. Dosage knob; 31. Push block; 32. Limiting plate; 33. Support block; 34. Limiting block;
[0049] 4. Push rod rotary cylinder; 41. Positioning ring; 42. Second rack;
[0050] 5. Gear on the rotating drum; 51. Ring spring; 511. First spring section; 512. Second spring section; 52. First rack; 53. Body; 54. First flange; 55. Second flange; 56. Groove. Detailed Implementation
[0051] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0052] In this document, when it is mentioned that a first component is located on a second component, this can mean that the first component can be directly formed on the second component, or that a third component can be inserted between the first and second components. Furthermore, in the accompanying drawings, the thickness of the components may be exaggerated or reduced for the purpose of effectively describing the technical content.
[0053] In this document, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than individual elements in the list. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.
[0054] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise clearly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.
[0055] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.
[0056] Research has revealed that a Chinese patent application with related technical announcement number CN201324413Y discloses a quantitative adjustable pen syringe, including a fixed tube, a pusher, a sleeve, a clutch sleeve, rotating teeth, a screw, a transmission tube, a stop ring, a fixed ring, a rotating tube, a central rotating toothed cylinder, a transmission toothed cylinder, and a sleeve. It adjusts the pre-injection dose by rotating the end of the rotating tube to adjust its position relative to the sleeve. During the inward pressing of the rotating tube, the rotating tube drives the central rotating toothed cylinder, the transmission toothed cylinder, the transmission tube, the rotating teeth, and the screw to rotate, thereby propelling the screw forward relative to the sleeve and quantitatively injecting the injection solution placed in the fixed tube into the human body. It also has an internal anti-reverse mechanism, preventing the pusher from retracting even when the rotating tube is adjusted backward for the next injection.
[0057] The aforementioned adjustable-quantity pen injector actually rotates by rotating the tube, driving the central gear cylinder, transmission gear cylinder, transmission tube, rotating gears, and screw, thereby propelling the screw forward relative to the socket. However, the aforementioned adjustable-quantity pen injector has the following shortcomings:
[0058] 1. The forward and reverse adjustment mechanism is bulky, requiring a larger internal space in the syringe, which limits the portability design.
[0059] 2. Multiple sets of ratchet structures are required to achieve forward and reverse rotation, which is complex, has a large number of parts, and a high assembly error rate, affecting dosage accuracy.
[0060] Therefore, how to solve the above-mentioned defects is a technical problem that urgently needs to be solved in this field.
[0061] The defects in the above solutions and the reasons for their occurrence are the results of the inventors' practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed in this disclosure should be considered as the inventors' contributions to this disclosure.
[0062] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0063] The following detailed description, with reference to the accompanying drawings, describes some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0064] like Figures 1 to 6 As shown, at least one embodiment provides a forward / reverse adjustment mechanism for a syringe, comprising: a rotary gear 2 fixed inside a pen body 1; the end wall of the rotary gear 2 is provided with ratchet 22, the ratchet 22 facing an annular spring 51; a dosage knob 3 rotatably disposed at the end of the pen body 1, used to drive the rotary gear 5 to rotate forward and reverse; the rotary gear 5 rotates forward to drive the push rod rotary cylinder 4 to rotate to wind a coil spring inside the pen body 1, thereby adjusting the injection dosage of the syringe; the inner wall of the dosage knob 3 matches the rotary gear 5, and the dosage knob 3 can rotate circumferentially relative to the rotary gear 5; when the dosage knob 3 rotates forward, the dosage knob 3 drives the rotary gear 5 to rotate synchronously forward. When the dosage knob 3 rotates in reverse, the dosage knob 3 rotates freely relative to the rotary gear 5 until the push block 31 pushes the annular spring 51 to deform, and the dosage knob 3 drives the rotary gear 5 to rotate synchronously in reverse. The push rod rotating cylinder 4 is coaxially arranged with the upper rotating cylinder gear 5 and is adapted to move axially relative to the pen body 1. The upper rotating cylinder gear 5 is sleeved on the outer wall of the push rod rotating cylinder 4 and meshes with the rotating cylinder gear 2. When the upper rotating cylinder gear 5 rotates in the forward direction, the annular spring 51 abuts against the ratchet 22 in sequence to prevent the upper rotating cylinder gear 5 from rotating in the reverse direction. Specifically, when the dosage knob 3 rotates in the forward direction, the upper rotating cylinder gear 5 rotates in the forward direction relative to the rotating cylinder gear 2 to pressurize the coil spring inside the pen body 1. When the dosage knob 3 rotates in the reverse direction, the annular spring 51 is pushed and elastically deformed by the push block 31, so that the annular spring 51 disengages from the ratchet 22, and the upper rotating cylinder gear 5 rotates in the reverse direction relative to the ratchet 22 to release the coil spring and reduce the injection dose. Through the cooperation of the rotating cylinder gear 2, the upper rotating cylinder gear 5, and the dosage knob 3, forward and reverse adjustment can be achieved with only a single gear mechanism. Compared to traditional syringes that rely on multiple ratchet structures to adjust forward and reverse rotation, this invention significantly simplifies the internal structure, reduces the number of parts, and compresses the internal space occupied by the pen body 1.
[0065] Reference Appendix Figure 3The rotating drum gear 5 has two annular spring pieces 51 on its side wall. One end of each annular spring piece 51 extends circumferentially along the rotating drum gear 5 in the same direction, and the other end extends obliquely toward the ratchet 22 and engages with each ratchet 22. When the dosage knob 3 is rotated in the forward direction, the annular spring pieces 51 strike the ratchet 22 in sequence to produce a sound. The sound here refers to the impact sound produced by the annular spring pieces 51 striking the ratchet 22, which alerts the user. The annular spring piece 51 includes a first spring piece 511 and a second spring piece 512. The first spring piece 511 is disposed on the side wall of the first flange 54. There is a gap between the inner wall of the first spring piece 511 and the outer wall of the body 53. The first spring piece 511 and the second spring piece 512 are integrally disposed. The second spring piece 512 is disposed at the end of the first spring piece 511 and has an included angle relative to the first spring piece 511. The second spring piece 512 engages with the ratchet 22. The arrangement of the first spring piece 511 and the second spring piece 512 ensures that the deformation of the annular spring piece 51 is controllable and durable. The ratchet 22 is at the same tilt angle as the annular spring piece 51; wherein, when the dosage knob 3 stops rotating, the ratchet 22 can prevent the gear 5 on the rotating drum from rotating in the opposite direction, so as to ensure the accuracy of adjusting the syringe dosage.
[0066] Reference Appendix Figure 2 The inner wall of the dosage knob 3 is provided with two push blocks 31, each push block 31 corresponding to an annular spring 51; the annular spring 51 overlaps the corresponding push block 31. When the dosage knob 3 rotates in the reverse direction, it rotates relative to the gear 5 on the rotating drum. The push block 31 abuts against the annular spring 51, pushing the annular spring 51 to elastically deform, causing the annular spring 51 to disengage from the ratchet 22. At this time, the dosage knob 3 drives the gear 5 on the rotating drum to rotate synchronously in the reverse direction, causing the gear 5 on the rotating drum to rotate in the opposite direction relative to the ratchet 22. The push block 31 is located between the annular spring 51 and the rotating drum gear 2.
[0067] Reference Appendix Figure 3 The rotating cylinder gear 5 includes: a body 53, which is annular and sleeved on the outer wall of the push rod rotating cylinder 4; when the dosage knob 3 rotates in the forward direction, it drives the body to rotate synchronously, and the body synchronously drives the push rod rotating cylinder 4 to rotate synchronously. Two first flanges 54 are symmetrically arranged on the outer wall of the body 53; two second flanges 55 are symmetrically arranged on the outer wall of the body 53 and located between the two first flanges 54; a groove 56 is provided between the sidewalls of the first flanges 54 and the sidewalls of the second flanges 55; a limiting block 34 on the inner wall of the dosage knob is slidably disposed in the groove. The annular spring piece 51 extends circumferentially from the sidewall of the first flange 54 along the body 53.
[0068] Reference Appendix Figure 2The dosage knob 3 is provided with a limiting plate 32, which is sleeved on the outer wall of the push rod rotating cylinder 4 and abuts against the side wall of the gear 5 on the rotating cylinder away from the rotating cylinder gear 2; the inner wall of the dosage knob 3 is provided with two support blocks 33, which are located between the two push blocks 31, and the support blocks 33 and the limiting plate 32 are respectively located on both sides of the body 53. The inner wall of the dosage knob 3 is also provided with two limiting blocks 34. The limiting blocks 34 are located within the groove 56 and are adapted to slide within the groove 56. When the dosage knob 3 rotates in the forward direction, the limiting blocks 34 slide to abut against the second flange 55 to push the body 53 to rotate synchronously in the forward direction. When the dosage knob 3 rotates in the reverse direction, the limiting blocks 34 slide towards the side of the first flange 54. The pusher block 31 first pushes the annular spring 51 to elastically deform until it disengages from the ratchet 22, and then the limiting blocks 34 abut against the first flange 54 to push the body 53 to rotate synchronously in the reverse direction. (See attached diagram) Figure 4 and Figure 6 The inner wall of the upper gear 5 on the rotating drum is evenly distributed with several first racks 52. A positioning ring 41 is provided on the outer wall of the push rod rotating drum 4, and several second racks 42 are symmetrically arranged on the outer wall of the positioning ring 41. The second racks 42 mesh with the first racks 52. The engagement of the first racks 52 and the second racks 42 prevents the upper gear 5 from rotating relative to the push rod rotating drum 4. The engagement of the first racks 52 and the second racks 42 prevents the upper gear 5 from rotating synchronously with the rotating drum gear 2. The axial thickness of the positioning ring 41 is greater than the axial thickness of the upper gear 5 on the rotating drum.
[0069] Reference Appendix Figure 5 A coil spring bracket 21 is provided on the side of the rotating drum gear 2 away from the upper gear 5 of the rotating drum, and the other end of the coil spring bracket 21 is fixed to the end wall of the dial. The coil spring is located inside the coil spring bracket 21, the inner end of the coil spring is fixed to the outer wall of the push rod rotating drum 4, and the outer end of the coil spring is fixed to the inner wall of the coil spring bracket 21.
[0070] Reference Appendix Figure 1 At least one embodiment provides an injection pen that also includes a button 10 disposed at the outer end of the push rod cylinder 4. The button 10 is axially slidable relative to the dosage knob 3.
[0071] When button 10 is pushed towards pen body 1, button 10 pushes the push rod cylinder 4 to move axially into pen body 1 to activate the coil spring.
[0072] The working principle is as follows:
[0073] Before injecting the medication, rotate the dosage knob 3 clockwise. The dosage knob 3 drives the gear 5 on the rotating cylinder to rotate synchronously. The gear 5 on the rotating cylinder drives the push rod rotating cylinder 4 to rotate synchronously to compress the torsion spring. After the dial rotates to the required scale, press the button 10. The button 10 activates the coil spring, thereby driving the transmission linkage inside the pen body 1 to drive the pen core inside the pen body 1 to inject the medication in a measured amount. When the dosage knob 3 is rotated clockwise, the gear 5 on the rotating cylinder rotates relative to the pen body 1. The annular spring 51 abuts against the ratchet 22 in sequence to prevent the gear 5 on the rotating cylinder from retracting.
[0074] If the dosage knob 3 is rotated excessively, i.e., the dial rotates beyond the required scale, the dosage knob 3 is rotated in the opposite direction. The dosage knob 3 rotates in the opposite direction relative to the gear 5 on the rotating cylinder. The push block 31 pushes the annular spring 51 to deform, so that the annular spring 51 disengages from the ratchet 22. At this time, the dosage knob 3 rotates in the opposite direction, driving the gear 5 on the rotating cylinder to rotate synchronously in the opposite direction, so as to release the elastic force on the torsion spring, until the dial reaches the preset scale. When the dosage knob is rotated in the forward direction, it is used to increase the injection dose of the syringe; when the dosage knob is rotated in the reverse direction, it is used to decrease the injection dose of the syringe.
[0075] In the description of the embodiments of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0076] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence unless expressly indicated herein. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed above may be referred to as the second element, component, region, layer, or segment.
[0077] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.
Claims
1. A forward / reverse adjustment mechanism for a syringe, characterized in that, include: Rotary gear (2), which is fixed inside the pen body (1), and ratchet (22) is provided on the end wall of the rotary gear (2); Dosage knob (3), which is rotated at the end of the pen body (1); push rod cylinder (4), which is coaxially arranged with the cylinder gear (2) and is adapted to move axially relative to the pen body (1); The upper gear (5) of the rotating drum is set inside the dosage knob (3), sleeved on the outer wall of the push rod rotating drum (4), and meshes with the rotating drum gear (2); When the dosage knob (3) is rotated in the forward direction, the drive cylinder upper gear (5) rotates in the forward direction relative to the cylinder gear (2) to drive the push rod cylinder (4) to rotate to wind the coil spring inside the pen body (1); When the dosage knob (3) is rotated in the opposite direction, the upper gear (5) of the drum is pushed by the dosage knob (3) to move away from the drum gear (2) and disengage from the ratchet (22) so that the upper gear (5) of the drum rotates in the opposite direction relative to the drum gear (2).
2. The forward / reverse adjustment mechanism for a syringe as described in claim 1, characterized in that, The upper gear (5) of the rotating drum is provided with two annular spring pieces (51) on its peripheral wall. One end of each annular spring piece (51) extends circumferentially along the upper gear (5) of the rotating drum in the same direction. The other end of each annular spring piece (51) extends obliquely toward the rotating drum gear (2) and meshes with the corresponding ratchet (22). When the dosage knob (3) is rotated in the forward direction, the two ring-shaped springs (51) strike each ratchet (22) in sequence to produce a sound.
3. The forward / reverse adjustment mechanism for a syringe as described in claim 2, characterized in that, The inner wall of the dosage knob (3) is provided with two push blocks (31), one push block (31) corresponds to one annular spring (51), and the annular spring (51) overlaps on the corresponding push block (31); When the dosage knob (3) is rotated in the reverse direction, the push block (31) pushes the annular spring (51) to elastically deform away from the rotary gear (2), and the annular spring (51) disengages from the ratchet (22). So that the upper gear (5) of the rotating drum rotates in the opposite direction to the rotating drum gear (2).
4. The forward / reverse adjustment mechanism for a syringe as described in claim 3, characterized in that, The upper gear (5) of the rotating drum includes: The main body (53) is circular and is fitted on the outer wall of the push rod cylinder; The first flange (54) is symmetrically arranged on the outer side wall of the body (53); The second flange (55) is symmetrically arranged on the outer wall of the body (53) and located between the two first flanges (54); A groove (56) is provided between the side wall of the first flange (54) and the side wall of the second flange (55); The annular spring (51) extends circumferentially from the sidewall of the first flange (54) along the body (53).
5. The forward / reverse adjustment mechanism for a syringe as described in claim 4, characterized in that, The annular spring (51) includes a first spring (511) and a second spring (512). The first spring (511) is disposed on the side wall of the first flange (54), and the second spring (512) is disposed at the end of the first spring (511) and has an angle relative to the first spring (511). The second segment of the spring (512) engages with the ratchet (22).
6. The forward / reverse adjustment mechanism for a syringe as described in claim 4, characterized in that, The dosage knob (3) is provided with a limiting plate (32), which is sleeved on the outer wall of the push rod cylinder (4) and abuts against the side wall of the upper gear (5) away from the cylinder gear (2); The inner wall of the dosage knob (3) is provided with two support blocks (33), which are located between the two push blocks (31), and the support blocks (33) and the limiting plate (32) are respectively located on both sides of the body (53).
7. The forward / reverse adjustment mechanism for a syringe as described in claim 6, characterized in that, The inner wall of the dosage knob (3) is also provided with two limiting blocks (34), the limiting blocks (34) are located in the groove (56), and the limiting blocks (34) are adapted to slide in the groove (56); When the dosage knob (3) is rotated in the forward direction, the limiting block (34) slides to abut against the second flange (55) to push the body (53) to rotate in the forward direction synchronously. When the dosage knob (3) is rotated in the reverse direction, the limiting block (34) slides to the side of the first flange (54), and the push block (31) first pushes the annular spring (51) to deform elastically until it disengages from the ratchet (22), and then the limiting block (34) abuts against the first flange (54) to push the body (53) to rotate in the reverse direction synchronously.
8. The forward / reverse adjustment mechanism for a syringe as described in claim 2, characterized in that, The inner wall of the body is evenly distributed with several first toothed strips (52) in the circumferential direction. A positioning ring (41) is provided on the outer wall of the push rod rotary cylinder (4), and a plurality of second racks (42) are symmetrically arranged on the outer wall of the positioning ring (41). The second racks (42) mesh with the first racks (52).
9. The forward / reverse adjustment mechanism for a syringe as described in claim 1, characterized in that, A coil spring bracket (21) is provided on the side of the rotary gear (2) away from the upper gear (5) of the rotary drum, and the other end of the coil spring bracket (21) is fixed to the end wall of the dial. The coil spring is located inside the coil spring bracket (21), the inner end of the coil spring is fixed to the outer wall of the push rod rotating cylinder (4), and the outer end of the coil spring is fixed to the inner wall of the coil spring bracket (21).
10. An injection pen, characterized in that, include: The syringe forward / reverse adjustment mechanism according to any one of claims 1-9 includes a button (10) disposed at the outer end of the plunger cylinder (4) and axially slidable relative to the dosage knob (3).