Injection pen and plunger rod securing structure
By designing a fixing structure for the injection pen push rod and utilizing a combination of brackets, sleeves, and fixing springs, the problem of difficult push rod assembly was solved, achieving efficient assembly of the injection pen.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANGHAI PEIYU MEDICAL EQUIPMENT CO LTD
- Filing Date
- 2025-03-26
- Publication Date
- 2026-06-19
AI Technical Summary
The assembly of the plunger in existing injection pens is difficult, involves many steps, and requires additional tools, resulting in low assembly efficiency.
Design a fixation structure for an injection pen push rod, including a bracket, a sleeve, a fixing spring, and a fixing frame. By using a stop ring, a notch, and a spring piece, the fixation process of the push rod is simplified, allowing it to connect to the back cover and reducing assembly difficulty.
By simplifying the process of fixing the push rod, the overall assembly difficulty of the injection pen is reduced, and the assembly efficiency is improved.
Smart Images
Figure CN224370371U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of medical device technology, specifically relating to syringes, and more particularly to an injection pen and a plunger fixing structure. Background Technology
[0002] For chronic diseases, medical staff and patients who self-administer medications at home often use injection pens to inject drugs to achieve the purpose of treating chronic diseases. Injection pen drug therapy can be divided into diabetes treatment, growth hormone treatment, osteoporosis treatment, fertility treatment, and other treatments.
[0003] In related technologies, the plunger is a core component of the injection pen. Before the plunger is fixed and assembled, the retaining clip needs to be inserted into the bracket, and then the bracket is fixed to the back cover. The four protrusions on the inner wall of the sleeve act as a settling device. A retaining spring is placed on the bracket, and then the sleeve is put on. The retaining clip is fixed upwards, so that the two wings below the retaining clip are against the bracket, while the sleeve is pressed down. However, at this time, the protrusions on the inner wall of the sleeve are blocked by the two spring clips of the retaining clip. Tweezers or other methods are needed to push the spring clips inwards so that the sleeve can smoothly move forward. Move the sleeve down to the bottom; at this point, control the sleeve to expose the two spring pieces of the fixing clamp, then put the excitation spring on the thin rod of the back cover, and then use the push rod to compress the excitation spring downwards; when the stop on the push rod reaches the spring piece of the fixing clamp, keep the push rod still and slowly release the sleeve to wrap around the spring piece of the fixing clamp upwards, so that the spring piece cannot deform outwards, thus fixing the push rod; the above-mentioned push rod fixing not only involves many steps, but also requires additional tools, resulting in high overall assembly difficulty, slow speed, and low efficiency.
[0004] Therefore, how to solve the problem of difficult push rod assembly 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 the present application concept, and therefore, the above description is not considered to constitute prior art information. Utility Model Content
[0006] This disclosure provides at least one injection pen to solve the technical problem of difficult push rod assembly.
[0007] In a first aspect, embodiments of this disclosure provide an injection pen, comprising: a back cover; a push rod fixing structure connected to the back cover, the push rod fixing structure being adapted to clamp a push rod body; the push rod fixing structure comprising: a bracket connected to the back cover; a sleeve partially fitted onto the bracket, a stop ring fixed to the outer wall of the sleeve, and a notch provided at one end of the sleeve; a fixing spring, one end of which is fitted onto the bracket, and the other end abutting against one end of the stop ring; a fixing frame, one end of which is disposed within the bracket, and the other end of which is provided with a pair of spring pieces extending into the sleeve; wherein, the sleeve is configured to drive the stop ring to compress the fixing spring, causing the spring pieces to open to drive the push rod body to move toward the needle of the injection pen.
[0008] In one alternative embodiment, the injection pen includes: at least one retaining strip; a first through hole provided on the side wall of the rear cover; a second through hole provided on the bracket; both the first and second through holes being adapted to the retaining strip; the bracket having a plug-in end adapted to an insertion hole; the plug-in end being configured to be inserted into the insertion hole of the rear cover such that the first and second through holes are aligned; the retaining strip passes sequentially through the first and second through holes to connect the bracket and the rear cover.
[0009] In one alternative embodiment, the device includes an excitation spring; a long rod is disposed at the center of the rear cover, and at least a portion of the excitation spring is sleeved on the long rod.
[0010] In one optional embodiment, one end of the push rod body is provided with a limiting hole, and one end of the actuating spring extends into the limiting hole; the surface of the push rod body is provided with a pair of locking grooves, which are adapted to abut against the spring piece.
[0011] Secondly, this disclosure also provides a push rod fixing structure, including: a bracket; a sleeve, partly fitted on the bracket and the remainder suspended outside the bracket, a stop ring fixed to the outer wall of the sleeve, and a notch provided at one end of the sleeve; a fixing spring, one end of which is fitted on the bracket and the other end abutting against one end of the stop ring; a fixing frame, one end of which is disposed inside the bracket and the other end is provided with a pair of spring pieces extending into the sleeve, the spring pieces being adapted to clamp the push rod body; wherein, the sleeve is configured to drive the stop ring to compress the fixing spring, causing the spring pieces to open to drive the push rod body to move towards the needle of the injection pen.
[0012] In one optional embodiment, the outer wall of the bracket is provided with a pair of opening slots along the length direction, and one end of the fixing frame is provided with a pair of lugs. The lugs extend through the opening slots to the outside of the bracket, and one end of the lugs abuts against the other end of the fixing spring.
[0013] In one optional embodiment, a guide groove is provided along the length direction of the opening groove; the inner wall of the sleeve is provided with a rib, which can slide along the guide groove; wherein, the sleeve compresses and fixes the spring by moving along the guide groove.
[0014] In one optional embodiment, an undercut is provided on one inner wall of the opening groove, the width of the undercut gradually increasing along the extension direction of the opening groove; the ear block is located between the undercut and the terminating end face.
[0015] In one optional embodiment, the inner wall of the spring is provided with a locking protrusion that is adapted to a locking groove provided on the push rod body.
[0016] The beneficial effects of this utility model are that it provides an injection pen that connects the bracket, sleeve, fixing spring and fixing frame into a whole, and fixes the bracket to the back cover, reducing the difficulty of fixing the push rod to the fixing frame, thereby reducing the overall assembly difficulty of the injection pen and improving assembly efficiency.
[0017] 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.
[0018] 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
[0019] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art 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.
[0020] Figure 1 A perspective view of the unfolded state of a portion of the injection pen structure provided in an embodiment of this disclosure;
[0021] Figure 2 A perspective view of the push rod fixing structure provided in the embodiments of this disclosure;
[0022] Figure 3 Exploded view of the sleeve, bracket, and fixing frame provided in the embodiments of this disclosure;
[0023] Figure 4 A perspective view showing the connection between the push rod fixing structure, the rear cover, and the push rod body provided in an embodiment of this disclosure;
[0024] Figure 5 A perspective view showing the connection between the rear cover, the excitation spring, and the push rod body provided in an embodiment of this disclosure;
[0025] Figure 6 A perspective view of the back cover provided in an embodiment of this disclosure;
[0026] Figure 7 A perspective view of an injection pen provided for an embodiment of this disclosure.
[0027] In the picture:
[0028] 1. Back cover; 11. Long rod; 12. Insertion hole; 13. First through hole;
[0029] 2. Bracket; 21. Opening groove; 22. Guide groove; 23. Second through hole; 24. Undercut; 25. Termination end face; 26. Insertion end;
[0030] 3. Sleeve; 31. Stop ring; 32. Notch; 33. Rib;
[0031] 4. Fix the spring;
[0032] 5. Fixing bracket; 51. Ear block; 52. Spring clip; 53. Locking protrusion;
[0033] 6. Activate the spring;
[0034] 7. Push rod body; 71. Locking groove; 72. Limiting hole;
[0035] 8. Card strip. Detailed Implementation
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] 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.
[0041] Research revealed the following drawbacks of existing technologies: In related technologies, the plunger is a core component of the injection pen. Before assembling the plunger, a retaining clip needs to be inserted into the bracket, and then the bracket is fixed to the back cover. The four protrusions on the inner wall of the sleeve hinder the device. A retaining spring is placed on the bracket, and then the sleeve is placed on top. The retaining clip is fixed upwards, so that the two wings below the retaining clip are against the bracket, while the sleeve is pressed down. However, at this time, the protrusions on the inner wall of the sleeve are blocked by the two spring clips of the retaining clip, requiring the use of tweezers or similar methods to push the spring clips inwards. To ensure the sleeve moves smoothly downwards to the bottom, control the sleeve to expose the two spring clips of the retaining clamp. Then, place the excitation spring onto the thin rod of the back cover and use the push rod to compress the excitation spring downwards. When the stop on the push rod reaches the spring clip of the retaining clamp, keep the push rod stationary and slowly release the sleeve to wrap around the spring clip of the retaining clamp upwards. This prevents the spring clip from deforming outwards, thus fixing the push rod. The above-mentioned push rod fixing process involves many steps and requires additional tools, resulting in high assembly difficulty, slow speed, and low efficiency.
[0042] Therefore, how to solve the problem of difficult push rod assembly is a technical problem that urgently needs to be solved in this field.
[0043] The shortcomings of the above solutions are the result of the utility model inventor's practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed in this disclosure should be considered as contributions made by the utility model inventor to this disclosure.
[0044] 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.
[0045] 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.
[0046] like Figures 1 to 2 As shown, some embodiments provide a push rod fixing structure, including: a rear cover 1; a push rod fixing structure, which is used to fix the push rod body 7, facilitating the assembly of the push rod body 7, reducing the overall assembly difficulty of the injection pen; the push rod fixing structure is connected to the rear cover 1, and the push rod fixing structure is suitable for clamping the push rod body 7; the push rod fixing structure includes: a bracket 2, which is connected to the rear cover 1, and the connection between the bracket 2 and the rear cover 1 realizes the connection between the push rod fixing structure and the rear cover 1; a sleeve 3, which is partially fitted onto the bracket 2, and the sleeve 3 is fitted onto the bracket 2 from the insertion end 26 position of the bracket 2.
[0047] like Figure 2 and Figure 4 As shown, a stop ring 31 is fixed to the outer wall of the sleeve 3. The stop ring 31 is used to limit the fixed spring 4. The fixed spring 4 can be compressed or rebound by driving the movement of the sleeve 3. In addition, a notch 32 is provided at one end of the sleeve 3. The notch 32 is used to release the spring piece 52 when the sleeve 3 moves. The fixed spring 4 has one end sleeved on the bracket 2 and the other end abutting against one end of the stop ring 31. That is to say, part of the fixed spring 4 is sleeved on the connection section between the bracket 2 and the sleeve 3, and part of it is sleeved on the bracket 2. The fixed spring 4 is also sleeved on the bracket 2 from the insertion end 26 position of the bracket 2.
[0048] like Figure 2 and Figure 4 As shown, the fixing frame 5 has one end set inside the bracket 2, and the other end is provided with a pair of spring pieces 52 extending into the sleeve 3. The fixing frame 5 is inserted into the bracket 2 from the insertion end 26 position of the bracket 2. The spring pieces 52 are open outward in their natural state. The sleeve 3 squeezes the spring pieces 52 to deform them. When the spring pieces 52 are exposed from the notch 32 position, they will spring outward. The sleeve 3 is configured to drive the stop ring 31 to compress the fixing spring 4, so that the spring pieces 52 open and drive the push rod body 7 to move towards the needle of the injection pen. The fixing spring 4 rebounds and causes the sleeve 3 to retract, so that the push rod body 7 is squeezed between the two pressure spring pieces 52.
[0049] like Figure 1 , Figure 2 and Figure 7 As shown, at least one locking strip 8 is provided. In a preferred embodiment, the locking strips are configured as a pair. The side wall of the rear cover 1 is provided with a first through hole 13. The bracket 2 is provided with a second through hole 23. Both the first through hole 13 and the second through hole 23 are adapted to the locking strip 8. The locking strip 8 is used to lock in the first through hole 13 and the second through hole 23 to connect the push rod fixing structure to the rear cover 1. One end of the bracket 2 is a plug-in end 26, which is adapted to be inserted into the plug hole 12 on the rear cover 1. The plug-in end 26 is configured to be inserted into the plug hole 12 so that the first through hole 13 and the second through hole 23 are aligned. The locking strip 8 passes through the first through hole 13 and the second through hole 23 in sequence to connect the bracket 2 and the rear cover 1. During assembly, the plug-in end 26 is first inserted into the plug hole 12, and then the locking strip 8 passes through the first through hole 13 and the second through hole in sequence to realize the connection between the push rod fixing structure and the rear cover 1, so as to fix the push rod body 7 in the next step.
[0050] like Figure 1 and Figure 5 As shown, a long rod 11 is provided at the center of the rear cover 1, and an excitation spring 6 is sleeved on the long rod 11; one end of the excitation spring 6 extends to the outside of the long rod 11. A limiting hole 72 is provided at one end of the push rod body 7, and one end of the excitation spring 6 extends into the limiting hole 72; a pair of locking grooves 71 are provided on the surface of the push rod body 7, and the locking grooves 71 are adapted to abut against the spring 52. When the spring 52 springs open from the notch 32, the push rod body 7 is released from the squeezing force and is pushed out by the compressed excitation spring 6 to realize the drug delivery step of the syringe.
[0051] like Figures 1 to 4 As shown, some embodiments provide an injection pen, including: a bracket 2, a sleeve 3, a fixing spring 4, and a fixing frame 5. Part of the sleeve 3 is fitted onto the bracket 2, and the remaining part is suspended outside the bracket 2. The fixing spring 4 has one end fitted onto the bracket 2, and the other end abutting against one end of a stop ring 31. The fixing frame 5 has one end disposed inside the bracket 2, and the other end is provided with a pair of spring tabs 52 extending into the sleeve 3.
[0052] like Figure 3 As shown, a stop ring 31 is fixed to the outer wall of the sleeve 3, and a notch 32 is provided at one end of the sleeve 3; the spring piece 52 on the fixing frame 5 can pop out from the notch 32 position, and the spring piece 52 in the deformed state is suitable for clamping the push rod body 7; wherein, the sleeve 3 is configured to drive the stop ring 31 to compress the fixing spring 4, so that the spring piece 52 opens to place the push rod body 7; the fixing spring 4 rebounds to make the sleeve 3 retract, so that the push rod body 7 is squeezed between the two pressing spring pieces 52.
[0053] like Figure 3As shown, the outer wall of the bracket 2 has a pair of open slots 21 along its length. The open slots 21 penetrate the insertion end 26 of the bracket 2 axially and penetrate the outer wall of the bracket 2 radially. A guide slot 22 is provided along the length of the open slots 21, and the guide slot 22 is adjacent to the open slots. A termination end face 25 is formed between the open slots 21 and the guide slot 22. In a preferred embodiment, the guide slot 22 has a bottom surface, that is, the guide slot 22 does not penetrate the outer wall of the bracket 2. The inner wall of the sleeve 3 is provided with a rib 33, which can slide along the guide slot 22. The sleeve 3 compresses the fixing spring 4 by moving along the guide slot 22 toward the termination end face 25.
[0054] like Figures 1 to 4 As shown, a pair of lugs 51 are provided at one end of the fixing frame 5; the lugs 51 extend out of the bracket 2 through the opening slot 21; one end of the lugs 51 abuts against the other end of the fixing spring 4. An inverted buckle 24 is provided on one inner wall of the opening slot 21, and the width of the inverted buckle 24 gradually increases along the extension direction of the opening slot 21; one end of the lugs 51 abuts against the wide surface of the inverted buckle 24, and the other end abuts against the terminating end face 25 of the opening slot 21; wherein, the lugs 51 move along the length direction of the opening slot 21 to the space between the inverted buckle 24 and the terminating end face 25 to connect the bracket 2 and the fixing frame 5.
[0055] like Figures 1 to 4 As shown, the inner wall of the spring piece 52 is provided with a locking protrusion 53, which is adapted to the locking groove 71. The locking groove 71 is provided on the push rod body 7. The spring piece 52 opens to drive the push rod body 7 to move towards the needle of the injection pen. The spring piece 52 retracts to make the locking protrusion 53 extend into the locking groove 71 to connect the fixing frame 5 and the push rod body 7.
[0056] In summary, this utility model connects the bracket 2, sleeve 3, fixing spring 4 and fixing frame 5 into a whole, and fixes the bracket 2 to the back cover 1, reducing the difficulty of fixing the push rod 7 to the fixing frame 5, thereby reducing the overall assembly difficulty of the injection pen and improving assembly efficiency.
[0057] 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.
[0058] 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.
[0059] 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. An injection pen, characterized in that, include: Back cover (1); A push rod fixing structure is connected to the rear cover (1), and the push rod fixing structure is suitable for clamping the push rod body (7). The push rod fixing structure includes: The bracket (2) is connected to the back cover (1); The sleeve (3) is partially fitted onto the bracket (2). The outer wall of the sleeve (3) is fixed with a stop ring (31), and one end of the sleeve (3) is provided with a notch (32). A fixed spring (4) is fitted at one end onto the bracket (2), and at the other end abuts against one end of the stop ring (31); The fixing frame (5) has one end set inside the bracket (2) and the other end set with a pair of spring pieces (52) that extend into the sleeve (3); The sleeve (3) is configured to drive the stop ring (31) to compress the fixed spring (4), causing the spring piece (52) to open and drive the push rod body (7) to move toward the needle of the injection pen.
2. The injection pen of claim 1, wherein, include: At least one card strip (8); The side wall of the rear cover (1) is provided with a first through hole (13). The bracket (2) is provided with a second through hole (23); Both the first through hole (13) and the second through hole (23) are adapted to the card strip (8); The bracket (2) has a plug end (26) adapted to the socket (12). The plug end (26) is configured to be inserted into the plug hole (12) of the rear cover (1) so that the first through hole (13) is aligned with the second through hole (23); The clip (8) passes through the first through hole (13) and the second through hole (23) in sequence to connect the bracket (2) and the back cover (1).
3. The injection pen as described in claim 2, characterized in that, Including the excitation spring (6); A long rod (11) is provided at the center of the rear cover (1), and at least a portion of the excitation spring (6) is sleeved on the long rod (11).
4. The injection pen as described in claim 3, characterized in that, One end of the push rod body (7) is provided with a limiting hole (72), and one end of the excitation spring (6) extends into the limiting hole (72); The surface of the push rod body (7) is provided with a pair of locking grooves (71), which are adapted to abut against the spring piece (52).
5. A push rod fixing structure characterized by include: Support (2); The sleeve (3) is partially fitted onto the bracket (2), and the rest is suspended outside the bracket (2). The outer wall of the sleeve (3) is fixed with a stop ring (31), and one end of the sleeve (3) is provided with a notch (32). A fixed spring (4) is fitted at one end onto the bracket (2), and at the other end abuts against one end of the stop ring (31); The fixing frame (5) has one end set in the bracket (2) and the other end is provided with a pair of spring pieces (52) that extend into the sleeve (3). The spring pieces (52) are suitable for clamping the push rod body (7). The sleeve (3) is configured to drive the stop ring (31) to compress the fixed spring (4), causing the spring piece (52) to open and drive the push rod body (7) to move toward the needle of the injection pen.
6. The push rod fixing structure as described in claim 5, characterized in that, The outer wall of the bracket (2) is provided with a pair of opening slots (21) along the length direction. One end of the fixing frame (5) is provided with a pair of ear blocks (51). The ear blocks (51) extend through the opening slots (21) to the outside of the bracket (2). One end of the ear blocks (51) abuts against the other end of the fixing spring (4).
7. The push rod fixing structure as described in claim 6, characterized in that, A guide groove (22) is provided along the length direction of the opening groove (21), the guide groove (22) is adjacent to the opening groove (21), and a termination end face (25) is formed between the guide groove (22) and the opening groove (21). The inner wall of the sleeve (3) is provided with a rib (33), which can slide along the guide groove (22); The sleeve (3) compresses the fixed spring (4) by moving along the guide groove (22).
8. The push rod fixing structure as described in claim 7, characterized in that, An undercut (24) is provided on one inner wall of the opening groove (21), and the width of the undercut (24) gradually increases along the extension direction of the opening groove (21). The ear block (51) is located between the buckle (24) and the termination end face (25).
9. The push rod fixing structure as described in claim 5, characterized in that, The inner wall of the spring piece (52) is provided with a locking protrusion (53), which is adapted to the locking groove (71) provided on the push rod body (7).