Device for fixing stomach catheter

Abstract

The invention belongs to the technical field of catheter fixation, and particularly discloses a stomach catheter fixing device which comprises a mask assembly, the mask assembly comprises a mask body, a threaded boss and a catheter body, ear hanging grooves are symmetrically formed in the two sides of the mask body, and a middle round hole is formed in the middle of the mask body. The mask body is further provided with a special-shaped groove connected to the middle round hole from the edge. Original push-pull motion which is not easy to control manually and accurately is converted into rotary motion which is easy to control manually, so that the operation difficulty is greatly reduced, and the confidence of medical staff during operation is improved; meanwhile, the catheter body can be locked and fixed in a manner of wrapping and extruding from the outside through the opening type locking and fixing piece after intubation is completed.

Description

Technical Field

[0001] The present invention belongs to the technical field of catheter fixation, and specifically refers to a device for fixing a gastric catheter. Background Art

[0002] Gastric intubation is a commonly used diagnostic and therapeutic method in digestive medicine. The main process is to insert a catheter from the patient's mouth into the esophagus to achieve gastroscopy detection or other therapeutic effects.

[0003] Currently, the intubation process is mostly manually completed by medical staff, which is difficult. Its effect depends more on the personal skills and current state of the operator; and after intubation, it is often fixed with tape. On the one hand, it cannot be torn off and pasted multiple times and cannot come into contact with liquid; on the other hand, the fixing effect of the tape will significantly decrease over time. Summary of the Invention

[0004] In view of the above situation, to overcome the defects of the prior art, the present invention proposes a device for fixing a gastric catheter with low operation difficulty and good fixing effect; to solve the problem of high operation difficulty, this solution analyzes the specific operation difficulties: on the one hand, without limitation, the control accuracy and force of manual push-pull movement are much less than those of rotational movement (when rotating, the wrist is fixed, which is better for controlling accuracy); on the other hand, since the position where the catheter is inserted is a relatively fragile internal pipeline in the body, the psychological pressure of the operator is greater, resulting in the problem of "not daring to exert force".

[0005] To solve this problem, the present invention transforms the originally difficult-to-manually-precisely-control push-pull movement into an easily manually-controlled rotational movement, greatly reducing the operation difficulty and enhancing the confidence of medical staff during operation; at the same time, through an open-type locking and fixing member, after intubation, the catheter body can be locked and fixed by wrapping and squeezing from the outside.

[0006] Through the cooperation of this device, the operation difficulty of medical staff can be greatly reduced, the success rate and safety can be improved, and the scope of use can be expanded.

[0007] The technical solution adopted by the present invention is as follows: The present invention proposes a device for fixing a gastric catheter, including a mask assembly. The mask assembly includes a mask body, a threaded boss, and a catheter body. Ear hook grooves are symmetrically arranged on both sides of the mask body. A middle round hole is provided at the middle position of the mask body. There is also a special-shaped groove on the mask body that connects from the edge to the middle round hole. The threaded boss is fixedly connected to the outside of the mask body. The threaded boss and the special-shaped groove are coaxially arranged. The catheter body is located in the middle round hole and the catheter body is located in the special-shaped groove. A boss side groove matching the special-shaped groove is also provided on the threaded boss.

[0008] The special-shaped groove can facilitate the connection and separation of the catheter body and the mask body that have been intubated. The diameter of the middle circular hole is slightly larger than the width of the special-shaped groove, and the outer diameter of the cannula lining corresponds to the middle circular hole. When passing through the special-shaped groove, the cannula lining needs to be slightly squeezed to ensure the stability of the cannula lining in the middle circular hole.

[0009] Furthermore, it also includes a catheter precision delivery mechanism, which includes a support and guide assembly, a wheel-type precision feeding assembly and an anti-reversal locking assembly, the support and guide assembly is arranged on the threaded boss, the wheel-type precision feeding assembly is rotatably arranged in the support and guide assembly, and the anti-reversal locking assembly is arranged on the wheel-type precision feeding assembly.

[0010] The precise catheter delivery mechanism is a manual rotation feed control method, which, combined with the transmission ratio design, can significantly improve the stability of the catheter body when inserted into the human body, improve operational accuracy, and reduce dependence on the operator's personal skills.

[0011] Preferably, the support and guide assembly comprises a mounting sleeve and a square frame, the mounting sleeve is provided with a bottom thread, the mounting sleeve is threadedly connected via the bottom thread and the threaded boss, the square frame is rotatably arranged on the mounting sleeve, and the square frame is evenly distributed in an annular manner with fork frames.

[0012] As a further preferred embodiment of the present invention, the wheel-type precision feeding assembly includes a feed shaft, a feed roller and a bevel synchronous gear. The feed shaft is rotatably arranged in the fork frame part, the feed roller is fixedly connected to the middle position of the feed shaft, the feed roller is located in the fork frame part, and the bevel synchronous gear is symmetrically arranged at both ends of the feed shaft, and adjacent bevel synchronous gears are meshed for transmission.

[0013] The annularly evenly distributed wheel-type precision feeding assembly can synchronously apply axial movement force to the cannula liner from all directions through the meshing transmission of adjacent bevel synchronous gears, thereby achieving stable and slow feeding of the cannula liner.

[0014] Preferably, the anti-reverse locking assembly includes a manual shaft, a ratchet and an elastic pawl, the manual shaft is fixed to one of the feed shafts, a polygonal handle is provided at the end of the manual shaft, the ratchet is fixed to the manual shaft, external ratchets are evenly distributed in a ring on the ratchet, the elastic pawl is fixed to the square frame, an elastic bending portion is provided on the elastic pawl, and inner ratchets cooperating with the external ratchets are also arranged in an array on the arc portion of the elastic pawl, and a toggle handle is provided at the end of the elastic pawl.

[0015] Due to the movement of human muscles, the inner lining of the cannula during the insertion process may come out under the action of resistance. At this time, through the cooperation of the outer ratchet teeth and the inner ratchet teeth, the catheter body can be stably inserted into the human body and the catheter body can be prevented from slipping out when the hand is released.

[0016] Furthermore, it further includes an open-type locking and fixing member, which is composed of a handle portion and a tightening portion, and a side groove corresponding to the special-shaped groove is provided on the open-type locking and fixing member.

[0017] Preferably, elastic pieces are annularly and evenly arranged on the threaded boss, an external thread is provided on the outer surface of the elastic piece, a ramp portion is provided inside the tightening portion, and an internal thread matching the external thread is provided on the ramp portion.

[0018] After the cannulation is completed, the position of the catheter body can be locked by disassembling the catheter precise feeding mechanism and rotating and installing the open-type locking and fixing member.

[0019] As a further preference of the present invention, the mask assembly further includes an inner lining of the cannula, and the inner lining of the cannula is fixedly connected inside the elastic piece, and the inner lining of the cannula is arranged between the elastic piece and the catheter body.

[0020] The catheter precise feeding mechanism is a detachable independent module and can be reused, while the mask assembly cannot be reused.

[0021] The feeding roller is made of rubber material, and the ratchet wheel and the elastic ratchet pawl are made of metal material.

[0022] The beneficial effects achieved by the present invention adopting the above structure are as follows: (1) Through the special-shaped groove, it is convenient for the catheter body and the mask body that have completed the cannulation to be combined and separated. The diameter of the middle round hole is slightly larger than the width of the special-shaped groove, and the outer diameter size of the inner lining of the cannula corresponds to the middle round hole. When passing through the special-shaped groove, the inner lining of the cannula needs to be slightly extruded to ensure the stability of the inner lining of the cannula in the middle round hole.

[0023] (2) The catheter precise feeding mechanism is a manual rotation feeding control method. Combined with the transmission ratio design, it can significantly improve the stability when inserting the catheter body into the human body, improve the operation accuracy, and reduce the dependence on the personal technology of the operator.

[0024] (3) The annularly and evenly arranged wheel-type precise feeding assembly is driven by the meshing of adjacent conical synchronous gears, and can synchronously apply an axial moving force to the inner lining of the cannula from all directions, so as to realize the stable and slow feeding of the inner lining of the cannula.

[0025] (4) Due to the movement of human muscles, the inner lining of the cannula during the insertion process may be pulled out under the action of resistance. At this time, through the cooperation of the outer ratchet teeth and the inner ratchet teeth, the catheter body can be stably inserted into the human body, and the catheter body can be prevented from slipping out when the hand is released.

[0026] (5) After the cannulation is completed, by disassembling the catheter precise feeding mechanism and rotating the open-type locking and fixing parts, the position of the catheter body can be locked. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a combined three-dimensional view of the mask assembly and the catheter precise feeding mechanism; Figure 2 is a combined front view of the mask assembly and the catheter precise feeding mechanism; Figure 3 is a combined left view of the mask assembly and the catheter precise feeding mechanism; Figure 4 is a combined top view of the mask assembly and the catheter precise feeding mechanism; Figure 5 is Figure 2 the sectional view along the cutting line A-A in Figure 6 is Figure 3 the sectional view along the cutting line B-B in Figure 7 is a combined structural schematic diagram of the mask assembly and the catheter precise feeding mechanism; Figure 8 is a combined three-dimensional view of the mask assembly and the open-type locking and fixing parts; Figure 9 is a combined structural schematic diagram of the mask assembly and the open-type locking and fixing parts; Figure 10 is a sectional view of the mask assembly and the open-type locking and fixing parts; Figure 11 is Figure 6 the partial enlarged view at position I in Figure 12 is Figure 7 the partial enlarged view at position II in Figure 13 is Figure 5 the partial enlarged view at position III in Figure 14 is Figure 10 the partial enlarged view at position IV in Figure 15 is a schematic diagram of the operation process of this device.

[0028] Among them, 1. mask assembly, 2. catheter precise delivery mechanism, 3. open type locking fixture, 4. mask body, 5. threaded boss, 6. catheter body, 7. cannula lining, 8. ear hook slot, 9. middle round hole, 10. special-shaped slot, 11. boss side slot, 12. elastic sheet, 13. external thread, 14. support guide assembly, 15. wheel type precise feeding assembly, 16. anti-reversal locking assembly, 17. installation sleeve, 1 8. Square frame, 19. Feed shaft, 20. Feed roller, 21. Conical synchronous gear, 22. Manual shaft, 23. Ratchet, 24. Elastic pawl, 25. Bottom thread, 26. Fork frame part, 27. Polygonal handle, 28. External ratchet, 29. Elastic bending part, 30. Internal ratchet, 31. Toggle handle, 32. Handle part, 33. Tightening part, 34. Side groove, 35. Slope part, 36. Internal thread.

[0029] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be understood that terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “top”, “bottom”, “inside” and “outside” indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0032] like Figures 1 to 14 As shown, the present invention proposes a device for fixing a gastric catheter, including a mask assembly 1, the mask assembly 1 includes a mask body 4, a threaded boss 5 and a catheter body 6, ear hook grooves 8 are symmetrically provided on both sides of the mask body 4, a middle circular hole 9 is provided in the middle position of the mask body 4, and a special-shaped groove 10 connected from the edge to the middle circular hole 9 is provided on the mask body 4, the threaded boss 5 is fixedly connected to the outside of the mask body 4, the threaded boss 5 and the special-shaped groove 10 are coaxially arranged, the catheter body 6 is located in the middle circular hole 9, the catheter body 6 is located in the special-shaped groove 10, and the threaded boss 5 is also provided with a boss side groove 11 matching the special-shaped groove 10.

[0033] The special-shaped groove 10 can facilitate the connection and separation of the catheter body 6 and the mask body 4 that have been intubated. The diameter of the middle circular hole 9 is slightly larger than the width of the special-shaped groove 10, and the outer diameter of the cannula lining 7 corresponds to the middle circular hole 9. When passing through the special-shaped groove 10, the cannula lining 7 needs to be slightly squeezed to ensure the stability of the cannula lining 7 in the middle circular hole 9.

[0034] The device also includes a catheter precise delivery mechanism 2, which includes a support guide assembly 14, a wheel-type precise feeding assembly 15 and an anti-reversal locking assembly 16. The support guide assembly 14 is arranged on the threaded boss 5, the wheel-type precise feeding assembly 15 is rotatably arranged in the support guide assembly 14, and the anti-reversal locking assembly 16 is arranged on the wheel-type precise feeding assembly 15.

[0035] The catheter precise delivery mechanism 2 is a manual rotation feed control method, combined with the transmission ratio design, which can significantly improve the stability of the catheter body 6 when inserted into the human body, improve the operating accuracy, and reduce the dependence on the operator's personal skills.

[0036] The support guide assembly 14 includes a mounting sleeve 17 and a square frame 18. The mounting sleeve 17 is provided with a bottom thread 25. The mounting sleeve 17 is threadedly connected to the threaded boss 5 through the bottom thread 25. The square frame 18 is rotatably arranged on the mounting sleeve 17. The square frame 18 is evenly distributed with fork frames 26 in an annular shape.

[0037] The wheel-type precision feed assembly 15 includes a feed shaft 19, a feed roller 20 and a bevel synchronous gear 21. The feed shaft 19 is rotatably arranged in the fork frame part 26, and the feed roller 20 is fixedly connected to the middle position of the feed shaft 19. The feed roller 20 is located in the fork frame part 26. The bevel synchronous gear 21 is symmetrically arranged at both ends of the feed shaft 19, and adjacent bevel synchronous gears 21 are meshed and transmitted.

[0038] The annularly evenly distributed wheel-type precision feeding assembly 15 can synchronously apply axial movement force to the cannula liner 7 from all directions through the meshing transmission of adjacent bevel synchronous gears 21, thereby achieving stable and slow feeding of the cannula liner 7.

[0039] The anti-reverse locking assembly 16 includes a manual shaft 22, a ratchet 23 and an elastic pawl 24. The manual shaft 22 is fixedly connected to one of the feed shafts 19. A polygonal handle 27 is provided at the end of the manual shaft 22. The ratchet 23 is fixedly connected to the manual shaft 22. External ratchet teeth 28 are evenly distributed in a ring shape on the ratchet 23. The elastic pawl 24 is fixedly connected to the square frame 18. An elastic bending portion 29 is provided on the elastic pawl 24. Internal ratchets 30 that cooperate with the external ratchet teeth 28 are also arranged in an array on the arc portion of the elastic pawl 24. A toggle handle 31 is provided at the end of the elastic pawl 24.

[0040] Due to the movement of human muscles, the inner lining 7 of the cannula during the insertion process may come out under the action of resistance. At this time, through the cooperation of the outer ratchet teeth 28 and the inner ratchet teeth 30, the catheter body 6 can be stably inserted into the human body and the catheter body 6 can be prevented from slipping out when the hand is released.

[0041] It further includes an open-type locking and fixing member 3. The open-type locking and fixing member 3 is composed of a handle portion 32 and a tightening portion 33. A side groove 34 corresponding to the special-shaped groove 10 is provided on the open-type locking and fixing member 3.

[0042] Elastic sheets 12 are annularly and uniformly arranged on the threaded boss 5. External threads 13 are provided on the outer surface of the elastic sheets 12. An inclined ramp portion 35 is provided inside the tightening portion 33. Internal threads 36 matching the external threads 13 are provided on the inclined ramp portion 35.

[0043] After the cannulation is completed, by disassembling the catheter precise feeding mechanism 2 and rotating and installing the open-type locking and fixing member 3, the position of the catheter body 6 can be locked.

[0044] The mask assembly 1 further includes an inner lining 7 of the cannula. The inner lining 7 of the cannula is fixedly connected inside the elastic sheets 12. The inner lining 7 of the cannula is arranged between the elastic sheets 12 and the catheter body 6.

[0045] The catheter precise feeding mechanism 2 is a detachable independent module and can be reused, while the mask assembly 1 cannot be reused.

[0046] The feed roller 20 is made of rubber material, and the ratchet wheel 23 and the elastic ratchet pawl 24 are made of metal material.

[0047] As Figure 15 shown, the operation steps of the present device are as follows: Step 1: First, wear the mask body 4, and then insert the catheter body 6 through the mask body 4 into the patient's oral cavity and esophagus; Step 2: Install the catheter precise feeding mechanism 2. While rotating the installation sleeve 17, the square frame 18 does not rotate with the installation sleeve 17; Step 3: When directly rotating the manual rotating shaft 22, control the insertion or extraction of the catheter body 6; Step 4: Disassemble the catheter precise feeding mechanism 2, install the open-type locking and fixing member 3, and then control the constriction of the elastic sheets 12 by rotating the open-type locking and fixing member 3 to complete the fixation of the catheter body 6.

[0048] During specific use, first, the user needs to remove the open-type locking and fixing member 3, install the catheter precise feeding mechanism 2 through the threaded cooperation of the bottom thread 25 and the threaded boss 5, and pass the bottom end of the cannula through the space between each feed roller 20 and extend it to the target position.

[0049] Then, the polygonal handle 27 is rotated, and one of the feed shafts 19 can be rotated through the manual shaft 22. Since the feed shafts 19 are synchronously linked through the bevel synchronous gear 21, when one feed shaft 19 rotates, the regional feed shaft 19 and the feed roller 20 will also rotate accordingly; By designing the direction of the bevel synchronous gear 21, when each feed shaft 19 rotates, the movement direction applied to the catheter body 6 by the feed roller 20 is the same. Therefore, under the action of this force, the catheter body 6 will gradually penetrate deeper into the human body.

[0050] Due to the cooperation between the outer ratchet 28 and the inner ratchet 30, during the penetration of the catheter body 6, the sliding engagement of the outer ratchet 28 and the inner ratchet 30 is achieved through the bending of the elastic bending portion 29. After the hand is released, even if the catheter body 6 is subjected to a force forcing itself to retreat, the manual shaft 22 and the feed shaft 19 cannot rotate due to the blocking effect of the inner ratchet 30.

[0051] If you want to partially withdraw the catheter body 6, you only need to use your other hand to push the toggle handle 31 upward to manually separate the outer ratchet 28 and the inner ratchet 30. At this time, the rotation direction of the manual shaft 22 is not restricted, and you can just rotate 22 in the reverse direction.

[0052] As another new embodiment of the present invention, after the intubation is completed, the catheter precision delivery mechanism 2 is removed as a whole by rotating the mounting sleeve 17 and completely removed from the other end of the catheter body 6; Then, the catheter body 6 is placed in the open locking fixture 3 through the side groove 34, and the threaded connection between the tightening portion 33 and the elastic sheet 12 is completed through the cooperation of the internal thread 36 and the external thread 13; Then, by rotating the handle portion 32, the threaded engagement depth of the tightening portion 33 and the elastic sheet 12 can be increased. Since the internal thread 36 of the tightening portion 33 is distributed on the slope portion 35, as the threaded engagement depth increases, each elastic sheet 12 will shrink inward with the catheter liner 7, contact and squeeze the catheter body 6 through the catheter liner 7; when the squeezing force reaches a certain level, the catheter body 6 can be fixed.

[0053] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0054] The above description of the present invention and its embodiments is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. In summary, if those of ordinary skill in the art are inspired by it and, without departing from the gist of the present invention, design similar structural forms and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present invention.

Claims

1. A device for fixing a gastric catheter, characterized in that: The invention comprises a mask assembly (1), wherein the mask assembly (1) comprises a mask body (4), a threaded boss (5) and a duct body (6); ear hook grooves (8) are symmetrically arranged on both sides of the mask body (4); a middle circular hole (9) is arranged in the middle of the mask body (4); a special-shaped groove (10) is also arranged on the mask body (4) from the edge to the middle circular hole (9); the threaded boss (5) is fixedly connected to the outside of the mask body (4); the threaded boss (5) and the special-shaped groove (10) are coaxially arranged; the duct body (6) is located in the middle circular hole (9); the duct body (6) is located in the special-shaped groove (10); and the threaded boss (5) is also provided with a boss side groove (11) matching the special-shaped groove (10).

2. The device for fixing a gastric catheter according to claim 1, characterized in that: The invention also comprises a catheter precision delivery mechanism (2), wherein the catheter precision delivery mechanism (2) comprises a support guide assembly (14), a wheel-type precision feeding assembly (15) and an anti-reversal locking assembly (16), wherein the support guide assembly (14) is arranged on the threaded boss (5), the wheel-type precision feeding assembly (15) is rotatably arranged in the support guide assembly (14), and the anti-reversal locking assembly (16) is arranged on the wheel-type precision feeding assembly (15).

3. The device for fixing a gastric catheter according to claim 2, characterized in that: The support guide assembly (14) comprises a mounting sleeve (17) and a square frame (18); the mounting sleeve (17) is provided with a bottom thread (25); the mounting sleeve (17) is threadedly connected to the threaded boss (5) via the bottom thread (25); the square frame (18) is rotatably mounted on the mounting sleeve (17); and fork bracket portions (26) are evenly distributed in an annular pattern on the square frame (18).

4. The device for fixing a gastric catheter according to claim 3, wherein: The wheel-driven precision feeding assembly (15) comprises a feeding shaft (19), a feeding roller (20) and a bevel synchronous gear (21); the feeding shaft (19) is rotatably arranged in a fork frame portion (26); the feeding roller (20) is fixedly connected to a middle position of the feeding shaft (19); the feeding roller (20) is located in the fork frame portion (26); the bevel synchronous gear (21) is symmetrically arranged at both ends of the feeding shaft (19); and adjacent bevel synchronous gears (21) are meshed and transmitted with each other.

5. The device for fixing a gastric catheter according to claim 4, wherein: The anti-reverse locking assembly (16) comprises a manual rotating shaft (22), a ratchet (23) and an elastic pawl (24); the manual rotating shaft (22) is fixedly connected to one of the feed rotating shafts (19); a polygonal handle (27) is provided at the end of the manual rotating shaft (22); the ratchet (23) is fixedly connected to the manual rotating shaft (22); external ratchet teeth (28) are evenly distributed in a ring shape on the ratchet (23); the elastic pawl (24) is fixedly connected to the square frame (18); an elastic bending portion (29) is provided on the elastic pawl (24); inner ratchet teeth (30) cooperating with the outer ratchet teeth (28) are also arranged in an array on the arc portion of the elastic pawl (24); and a toggle handle (31) is provided at the end of the elastic pawl (24).

6. The device for fixing a gastric catheter according to claim 1, characterized in that: It further includes an open-type locking and fixing member (3), and the open-type locking and fixing member (3) is composed of a handle portion (32) and a tightening portion (33). A side groove (34) corresponding to the special-shaped groove (10) is provided on the open-type locking and fixing member (3).

7. The device for fixing a gastric catheter according to claim 6, characterized in that: Elastic sheets (12) are annularly and evenly arranged on the threaded boss (5). External threads (13) are provided on the outer surfaces of the elastic sheets (12). A slope portion (35) is provided inside the tightening portion (33), and internal threads (36) matching the external threads (13) are provided on the slope portion (35).

8. A device for fixing a gastric catheter according to claim 7, characterized in that: The face mask assembly (1) further includes an intubation lining (7), and the intubation lining (7) is fixedly connected inside the elastic sheet (12). The intubation lining (7) is arranged between the elastic sheet (12) and the catheter body (6).

9. The device for fixing a gastric catheter according to claim 5, characterized in that: The catheter precise feeding mechanism (2) is a detachable independent module and can be reused, while the face mask assembly (1) cannot be reused.

10. A device for fixing a gastric catheter according to claim 5, characterized in that: The feed roller (20) is made of rubber, and the ratchet wheel (23) and the elastic pawl (24) are made of metal.

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