CN214387409U - Nasal endoscope catheter structure with soft and hard sheath - Google Patents

Abstract

The utility model discloses an intranasal endoscope catheter structure with soft and hard sheaths, which comprises a device handle and a guide sheath, wherein the guide sheath comprises a soft sheath and a hard sheath, the back end of the soft sheath is coaxially fixed at the front end of the device handle, the hard sheath can axially move back and forth along the surface of the soft sheath and can adjust the length of a bendable section at the front end of the soft sheath, and the device handle is provided with a hard sheath locking structure which can axially lock the hard sheath; the flexible sheath is internally provided with a liquid and instrument shared channel and an image illumination channel along the axial direction, the handle of the device is provided with a liquid and instrument shared joint communicated with the liquid and instrument shared channel and an image illumination device joint communicated with the image illumination channel, a steering steel wire is arranged in the flexible sheath, one end of the steering steel wire is fixed at the front end of the flexible sheath, and the other end of the steering steel wire is fixedly connected with a steering adjusting mechanism. The diagnosis and the operation process of the dilation of the nasal sinuses and the eustachian tube sacculus under the visual environment are realized by leading the optical fiber mirror into the image illumination channel, the bending angle and the length of the soft sheath can be respectively controlled by the deflector rod and the hard sheath, and the control is more flexible.

Description

Nasal endoscope catheter structure with soft and hard sheath

Technical Field

The utility model relates to the technical field of medical minimally invasive equipment, in particular to an intranasal endoscope catheter structure with a soft sheath and a hard sheath.

Background

The eustachian tube is the only channel connecting the tympanic cavity and the pharynx, if the eustachian tube has dysfunction and can not be normally opened, negative pressure of the middle ear can be caused, and the negative pressure is mainly manifested as the feeling of stuffiness and fullness of the ears and different degrees of conductive deafness or tinnitus. The treatment comprises non-operative treatment and operative treatment, and the conventional operative treatment is tympanocentesis and tympanostomy tube, which has the defects of damaging the tympanic membrane on one hand and possibly causing perforation of the tympanic membrane to require secondary operation repair on the other hand. Eustachian tube balloon dilatation is a new treatment method, a narrow eustachian tube is expanded through a balloon, the function of the eustachian tube is improved, the eustachian tube can better adjust the pressure in a tympanic cavity, the balance between the pressure in the tympanic cavity and the outside is maintained, middle ear dropsy can be rapidly discharged, secretory otitis media can be effectively cured, the tympanic membrane cannot be damaged in an operation, and the method has the advantages of simplicity, safety, minimally invasive performance and the like.

The eustachian tube balloon dilatation is characterized in that under the condition of general anesthesia or superficial anesthesia, a special balloon catheter is placed into a eustachian tube through a nasal cavity by a special placement device under the direct vision guidance of a nasal endoscope, water is injected into the balloon to pressurize to 10bar, the pressure is maintained for 2 minutes, then the pressure is released, the balloon catheter is taken out, and the operation is completed. The main equipment comprises: 1 catheter pusher, 3 guide heads (30 °, 45 ° and 70 °, respectively), 1 balloon catheter and 1 pressure pump. The front end of the catheter pusher can be connected with guide heads at different angles so as to be suitable for eustachian tubes at different angles, the balloon is positioned at the far end of the balloon catheter, the length of the balloon is 20mm, and the diameter of the balloon after expansion is about 3 mm. The tail end of the balloon catheter is fixed in the catheter pusher and enters the eustachian tube through the guide head, and the pusher can adjust the depth of the balloon placed in the eustachian tube.

The prior balloon dilatation surgical instrument has the following problems:

1. when the device is placed into the eustachian tube, blind expansion is adopted, so that the condition of the device in the eustachian tube cannot be visually observed;

2. the guide head is provided with three angles to match different embedding angles, but the limitation is large, the guide head is of a rigid structure and is not flexible enough to adapt to different cases;

3. the existing nose endoscope for direct-view guiding uses a hard lens, adopts a method of changing a multi-angle (viewing direction angle) lens to see different positions, has larger viewing angle, obvious image deformation and larger size of a lens body, and is inconvenient to use;

4. there is no specific aspiration path for the secretions from the ear after eustachian tube balloon dilation.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the defects of the background technology and provide an endoscope catheter structure which can observe the position of the instrument in the eustachian tube and has various embedded angles.

In order to realize the purpose, the utility model discloses an intranasal endoscope pipe structure with soft or hard sheath, including device handle and uide sheath, its characterized in that: the guide sheath comprises a soft sheath and a hard sheath, wherein the rear end of the soft sheath is coaxially fixed in the device handle, the hard sheath can axially move back and forth along the surface of the soft sheath and adjust the length of a bendable section at the front end of the soft sheath, and the device handle is provided with a hard sheath locking structure which can axially lock the hard sheath; the device comprises a soft sheath, a balloon catheter and a handle, wherein a liquid and instrument shared channel and an image illumination channel which can be used for inserting the balloon catheter are arranged in the soft sheath along the axial direction of the soft sheath, a liquid and instrument shared joint communicated with the liquid and instrument shared channel and an image illumination device joint communicated with the image illumination channel are arranged on the handle of the device, a steering steel wire is arranged in the soft sheath, one end of the steering steel wire is fixed at the front end of the soft sheath, and the other end of the steering steel wire is fixedly connected with a steering adjusting structure.

Further, sheath locking structure includes locking chuck and locking cap firmly, the locking chuck is fixed in including coaxial device handle front end inside, the locking chuck fixing base of cylinder and interval connect in locking chuck fixing base front end circumference surface, with a plurality of locking chuck stationary blades that the sheath is parallel firmly, the rear end of sheath is coaxial set up in locking chuck fixing base with in a plurality of locking chuck stationary blades, the internal surface of locking cap with be provided with respectively on the surface of a plurality of locking chuck stationary blades and can mutually support, make a plurality of locking chuck stationary blades are to the inboard shrink and are pressed from both sides tightly first cooperation structure and the second cooperation structure on sheath surface firmly.

Further, first cooperation structure including set up in external screw thread on the locking chuck stationary blade surface with set up in the direction inclined plane of locking chuck stationary blade front end, second cooperation structure including set up in internal thread on the locking cap internal surface with can with the cooperation of direction inclined plane, make a plurality ofly the direction taper hole of the inboard shrink of locking chuck stationary blade.

Furthermore, the locking chuck fixing seat is provided with a first limiting structure capable of limiting the axial forward movement position of the hard sheath along the surface of the soft sheath, and the front end of the soft sheath is provided with a second limiting structure capable of limiting the axial forward movement position of the hard sheath along the surface of the soft sheath.

Further, first limit structure including coaxial set up in the spacing round platform of hard sheath on hard sheath rear end surface with coaxial set up in the spacing round platform of locking chuck on locking chuck fixing base rear end surface, the external diameter of the spacing round platform of hard sheath is less than the external diameter of the spacing round platform of locking chuck, the spacing round platform of hard sheath is located the rear of the spacing round platform of locking chuck.

Further, the second limiting structure comprises an end cap coaxially fixed at the front end of the soft sheath, and a first end cap channel coaxially communicated with the liquid and instrument shared channel and a second end cap channel coaxially communicated with the image illumination channel are formed in the end cap; one end of the steering steel wire is fixed in the end cap, and the outer diameter of the end cap is not smaller than the outer diameter of the front end of the hard sheath.

Furthermore, the steering adjusting structure is a self-locking steering adjusting structure and comprises a steel wire wheel fixedly connected with the other end of the steering steel wire and a rotating shaft coaxially fixed with the steel wire wheel, two ends of the rotating shaft penetrate through the device handle and are fixedly connected with a deflector rod, a rotating shaft mounting support is arranged in the device handle, and a self-locking structure capable of enabling the rotating shaft to be self-locked is connected between the rotating shaft and the rotating shaft mounting support.

Further, the rotating shaft comprises a self-locking shaft section and a stepped shaft section which are positioned on the left side and the right side of the steel wire wheel, and the rotating shaft mounting support comprises a self-locking shaft section mounting support matched with the self-locking shaft section and a stepped shaft section mounting support matched with the stepped shaft section; the self-locking structure comprises a self-locking elastic sheet which is arranged between the right side surface of the steel wire wheel and the stepped shaft section mounting support and is in a compression state, and a locking surface and a locking hole which can be matched with each other and enable the self-locking shaft section to be locked in the self-locking shaft section mounting support through the elasticity of the self-locking elastic sheet are arranged on the self-locking shaft section and the self-locking shaft section mounting support.

Furthermore, the self-locking shaft section comprises a frustum-shaped shaft section, and the diameter of the surface of the frustum-shaped shaft section, which is close to one side of the steel wire wheel, is larger than the diameter of the surface of the frustum-shaped shaft section, which is far away from one side of the steel wire wheel; the locking surface is a frustum-shaped side surface of the frustum-shaped shaft section, and the locking hole is a frustum-shaped hole arranged in the self-locking shaft section mounting support.

Furthermore, the self-locking elastic sheet is coaxially arranged on the stepped shaft section, one side surface of the self-locking elastic sheet is in contact with the inner side surface of the stepped shaft section mounting support, and the other side surface of the self-locking elastic sheet is in contact with the right side surface of the steel wire wheel.

The utility model has the advantages that: through diagnosis and the operation process with leading-in image illumination passageway realization paranasal sinus and eustachian tube sacculus expansion of optical fiber mirror under the visual environment, the change of visual direction is realized at certain angle within range to soft sheath flexible drive optical fiber mirror, and the angle of observation is adjustable, and observation scope is wider. The bending angle and the length of the soft sheath can be controlled by the deflector rod and the hard sheath respectively, and the soft sheath can be self-locked after being bent, so that the control is more flexible, and the soft sheath can conveniently enter the cavity. The hard sheath can realize rigid picking, poking and other operations in the operation, and has multiple functions. The outer diameter and the length of the guide sheath can be designed into different sizes according to the sizes of the body types of adults or children, the guide sheath can extend into the eustachian tube after expansion to enter the inner ear for observation and diagnosis, flushing under the severe nasal sinus infection condition and the suction operation of the ear endocrine can be realized through the liquid and instrument shared channel, and the optical fiber scope can be kept clear through water injection of the liquid and instrument shared channel.

Drawings

FIG. 1 is a top view of an intranasal endoscope catheter structure of the present invention having a sheath that is rigid or flexible;

FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1;

FIG. 3 is a front view of the nasal endoscope catheter structure with the sheath of the present invention;

FIG. 4 is a cross-sectional view taken along line B-B of FIG. 3;

FIG. 5 is an enlarged view of FIG. 1 at C;

FIG. 6 is an axial cross-sectional view of a locking collet of the present invention;

FIG. 7 is an axial cross-sectional view of a locking cap of the present invention;

FIG. 8 is a front view of the connecting structure of the rotating shaft and the wire wheel in the present invention;

fig. 9 is an axial sectional view of the self-locking spring plate of the present invention;

fig. 10 is an axial cross-sectional view of a middle hard sheath according to the present invention;

FIG. 11 is an enlarged view of FIG. 10 at D;

the device comprises a device handle 1, a device handle 2, a soft sheath 3, a hard sheath 4, a liquid and instrument shared joint 5, an image lighting device joint, a steering steel wire 6, a locking chuck 7 (7.1, a locking chuck fixing seat, 7.2, a locking chuck fixing piece), a locking cap 8, an external thread 9, a guide inclined plane 10, an internal thread 11, a guide taper hole 12, a hard sheath limiting circular table 13, a locking chuck limiting circular table 14, an end cap 15, a steel wire wheel 16, a deflector rod 17, a rotating shaft 18 (18.1, a self-locking shaft section 18.2, a stepped shaft section 19, a self-locking shaft section mounting support 20, a self-locking elastic sheet 21, a tapered shaft section 22, a stepped shaft section mounting support 23, a fiberoptic endoscope catheter 24, a liquid and instrument shared catheter 24 and a distributor 25.

Detailed Description

The present invention will be described in further detail with reference to the following drawings and specific embodiments.

As shown in fig. 1-11, the nasal endoscope catheter structure with soft and hard sheaths comprises a device handle 1 and a guide sheath, wherein the guide sheath comprises a soft sheath 2 coaxially fixed at the rear end in the device handle 1 and a hard sheath 3 axially moving back and forth along the surface of the soft sheath 2 and adjusting the length of a bendable section at the front end of the soft sheath 2, a liquid and instrument shared channel and an image illumination channel are axially arranged in the soft sheath 2, the device handle 1 is provided with a liquid and instrument shared joint 4 communicated with the liquid and instrument shared channel through a liquid and instrument shared catheter 24 and an image illumination device joint 5 communicated with the image illumination channel through a fiberscope catheter 23, a steering steel wire 6 is arranged in the soft sheath 2, one end of the steering steel wire 6 is fixed at the front end of the soft sheath 2, and the other end is fixedly connected with a steering adjustment structure capable of self-locking: the steering device comprises a steel wire wheel 16 fixedly connected with the other end of the steering steel wire 6 and a rotating shaft 18 coaxially fixed with the steel wire wheel 16, wherein two ends of the rotating shaft 18 penetrate through a handle 1 of the device and are fixedly connected with a shifting lever 17, and a rotating shaft mounting support is arranged in the handle 1 of the device.

The rotating shaft 18 comprises a self-locking shaft section 18.1 and a stepped shaft section 18.2 which are positioned at the left side and the right side of the steel wire wheel 16, and the rotating shaft mounting support comprises a self-locking shaft section mounting support 19 matched with the self-locking shaft section 18.1 and a stepped shaft section mounting support 22 matched with the stepped shaft section 18.2; be provided with the auto-lock shell fragment 20 that is in compression state between steel wire wheel 16 right side surface and the step shaft section erection support 22, auto-lock shell fragment 20 coaxial sets up on step shaft section 18.2, a side surface and the inboard surface contact of step shaft section erection support 22 of auto-lock shell fragment 20, the right side surface contact of opposite side surface and steel wire wheel 16, auto-lock shell fragment 20 is dish-shaped shell fragment, the width of dish-shaped shell fragment and a side surface of step shaft section erection support 22 contact is less than the width of dish-shaped shell fragment and a side surface of auto-lock shaft section erection support 19 contact. The self-locking shaft section 18.1 comprises a frustum-shaped shaft section 21, the surface diameter of one side, close to the steel wire wheel 16, of the frustum-shaped shaft section 21 is larger than the surface diameter of one side, far away from the steel wire wheel 16, of the frustum-shaped shaft section 21, a frustum-shaped hole is formed in the self-locking shaft section mounting support 19, the frustum-shaped side surface of the frustum-shaped shaft section 21 is arranged in the frustum-shaped hole, and self-locking of the self-locking shaft section 18.1 in the self-locking shaft section mounting support 19 is achieved through elastic force of the self-locking elastic piece 20.

The device handle 1 is provided with a hard sheath locking structure for axially locking the hard sheath 3: comprises a locking chuck 7 and a locking cap 8, wherein the locking chuck 7 comprises a cylindrical locking chuck fixing seat 7.1 and a plurality of locking chuck fixing sheets 7.2 which are coaxially fixed inside the front end of a device handle 1 and are connected with the circumferential surface of the front end of the locking chuck fixing seat 7.1 at intervals and parallel to a hard sheath 3, the rear end of the hard sheath 3 is coaxially arranged in the locking chuck fixing seat 7.1 and the locking chuck fixing sheets 7.2, the outer surface of the locking chuck fixing sheet 7.2 is provided with an external thread 9, the front end of the locking chuck fixing sheet 7.2 is provided with a guide inclined plane 10, the inner surface of the locking cap 8 is provided with an internal thread 11 and a guide taper hole 12, the guide taper hole 12 is matched with the guide inclined plane 10 to ensure that the locking chuck fixing sheets 7.2 shrink inwards to clamp the surface of the hard sheath 3, and the hard sheath 3 can be locked in the axial direction by matching the internal thread 11 of the locking cap 8 with the external thread 9 of the locking chuck fixing piece 7.2 to ensure that the locking chuck fixing pieces 7.2 keep the state of clamping the surface of the hard sheath 3.

The locking chuck fixing seat 7.1 is provided with a first limiting structure capable of limiting the axial forward position of the hard sheath 3 along the surface of the soft sheath 2: the locking device comprises a hard sheath limiting round table 13 coaxially arranged on the surface of the rear end of a hard sheath 3 and a locking chuck limiting round table 14 coaxially arranged on the surface of the rear end of a locking chuck fixing seat 7.1, wherein the outer diameter of the hard sheath limiting round table 13 is smaller than that of the locking chuck limiting round table 14, and the hard sheath limiting round table 13 is positioned behind the locking chuck limiting round table 14.

The front end of the soft sheath 2 is provided with a second limiting structure which can limit the axial forward position of the hard sheath 3 along the surface of the soft sheath 2: the flexible sheath comprises an end cap 15 coaxially fixed at the front end of the flexible sheath 2, wherein a first end cap channel coaxially communicated with a shared channel of liquid and instruments and a second end cap channel coaxially communicated with an image illumination channel are arranged in the end cap 15; one end of the steering wire 6 is fixed in an end cap 15, and the outer diameter of the end cap 15 is larger than the outer diameter of the front end of the hard sheath 3.

The utility model discloses a use method who has the nose endoscope pipe structure of soft or hard sheath is: when the guide sheath is inserted and a rigid catheter is required to be picked or pulled, the hard sheath 3 can be moved to the front end of the soft sheath 2, and the locking cap 8 is screwed to lock the axial position of the hard sheath 3; when the soft sheath 2 needs to be bent for carrying out the fiberscope examination, the movable hard sheath 3 is exposed out of the front end of the soft sheath 2, and the deflector rod 17 is pulled to enable the soft sheath 2 to realize the bending operation. The flexible soft sheath 2 is arranged at the front section of the guide sheath, and can be matched with the rotation and other controls of a doctor on the handle 1 of the device in an operation, so that observation in a large range is facilitated, sinus ostia in different positions and angles can be found conveniently, the expansion balloon can accurately enter the nasal sinus ostia and the eustachian tube ostia conveniently, and expansion treatment can be implemented. After the expansion sacculus reachd the corresponding position of paranasal sinus and eustachian tube, can carry out the operation of water injection pressurization expansion to the sacculus, after the expansion, can directly or with the help of washing the drainage tube and stretch into corresponding paranasal sinus or the drainage operation in the middle ear from liquid and apparatus common channel, and can check up the operation effect, whole operation process all is accomplished under visual state, the security that has increased the operation, reliability and flexibility, it becomes more light to let the operation process.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the structure of the present invention in any way. Any simple modification, equivalent changes and modifications made to the above embodiments according to the technical spirit of the present invention all still fall within the scope of the technical solution of the present invention.

Claims (10)

1. An intranasal endoscopic catheter structure with a soft and hard sheath, comprising a device handle (1) and a guide sheath, characterized in that: the guide sheath comprises a soft sheath (2) with the rear end coaxially fixed in the device handle (1) and a hard sheath (3) which can axially move back and forth along the surface of the soft sheath (2) and adjust the length of a bendable section at the front end of the soft sheath (2), and the device handle (1) is provided with a hard sheath locking structure which can axially lock the hard sheath (3); the device is characterized in that a liquid and instrument shared channel and an image illumination channel which can be used for inserting a balloon catheter are formed in the soft sheath (2) along the axial direction of the soft sheath, a liquid and instrument shared joint (4) communicated with the liquid and instrument shared channel and an image illumination device joint (5) communicated with the image illumination channel are arranged on the device handle (1), a steering steel wire (6) is arranged in the soft sheath (2), one end of the steering steel wire (6) is fixed at the front end of the soft sheath (2), and the other end of the steering steel wire is fixedly connected with a steering adjusting structure.

2. The intranasal endoscopic catheter structure with a sheath of soft and hard material as set forth in claim 1, wherein: hard sheath locking structure includes locking chuck (7) and locking cap (8), locking chuck (7) are fixed in including coaxial device handle (1) front end inside, cylindrical locking chuck fixing base (7.1) and interval connect in locking chuck fixing base (7.1) front end circumference surface, with a plurality of locking chuck stationary blade (7.2) that hard sheath (3) is parallel, the rear end of hard sheath (3) coaxial set up in locking chuck fixing base (7.1) with in a plurality of locking chuck stationary blade (7.2), the internal surface of locking cap (8) with be provided with respectively on the surface of a plurality of locking chuck stationary blade (7.2) mutually support, make a plurality of locking chuck stationary blades (7.2) shrink and press from both sides to the inboard clamp first cooperation structure and the second cooperation structure on hard sheath (3) surface.

3. The intranasal endoscopic catheter structure with a soft or hard sheath as set forth in claim 2, characterized in that: first cooperation structure including set up in external screw thread (9) on locking chuck stationary blade (7.2) surface with set up in direction inclined plane (10) of locking chuck stationary blade (7.2) front end, second cooperation structure including set up in internal thread (11) on locking cap (8) internal surface and can with direction inclined plane (10) cooperation, make a plurality ofly locking chuck stationary blade (7.2) are to inboard direction taper hole (12) of contracting.

4. The intranasal endoscopic catheter structure with a soft or hard sheath as set forth in claim 2, characterized in that: the locking chuck fixing seat (7.1) is provided with a first limiting structure capable of limiting the axial forward movement position of the surface of the soft sheath (2) along the hard sheath (3), and the front end of the soft sheath (2) is provided with a second limiting structure capable of limiting the axial forward movement position of the surface of the soft sheath (2) along the hard sheath (3).

5. The intranasal endoscopic catheter structure with a sheath of soft and hard material as set forth in claim 4, wherein: first limit structure including coaxial set up in the spacing round platform of hard sheath (13) on hard sheath (3) rear end surface with coaxial set up in the spacing round platform of locking chuck (14) on locking chuck fixing base (7.1) rear end surface, the external diameter of the spacing round platform of hard sheath (13) is less than the external diameter of the spacing round platform of locking chuck (14), the spacing round platform of hard sheath (13) are located the rear of the spacing round platform of locking chuck (14).

6. The intranasal endoscopic catheter structure with a sheath of soft and hard material as set forth in claim 4, wherein: the second limiting structure comprises an end cap (15) coaxially fixed at the front end of the soft sheath (2), and a first end cap channel coaxially communicated with the liquid and instrument shared channel and a second end cap channel coaxially communicated with the image illumination channel are formed in the end cap (15); one end of the steering steel wire (6) is fixed in the end cap (15), and the outer diameter of the end cap (15) is not smaller than the outer diameter of the front end of the hard sheath (3).

7. The intranasal endoscopic catheter structure with a sheath of soft and hard material as set forth in claim 1, wherein: the steering adjusting structure is a self-locking steering adjusting structure and comprises a steel wire wheel (16) fixedly connected with the other end of the steering steel wire (6) and a rotating shaft (18) coaxially fixed with the steel wire wheel (16), two ends of the rotating shaft (18) penetrate through the device handle (1) and are fixedly connected with a shifting rod (17), a rotating shaft mounting support is arranged in the device handle (1), and a self-locking structure capable of enabling the rotating shaft (18) to be self-locked is connected between the rotating shaft (18) and the rotating shaft mounting support.

8. The intranasal endoscopic catheter structure with a sheath of soft and hard material as set forth in claim 7, wherein: the rotating shaft (18) comprises self-locking shaft sections (18.1) and stepped shaft sections (18.2) which are positioned on the left side and the right side of the steel wire wheel (16), and the rotating shaft mounting support comprises a self-locking shaft section mounting support (19) matched with the self-locking shaft sections (18.1) and a stepped shaft section mounting support (22) matched with the stepped shaft sections (18.2); the self-locking structure comprises a self-locking elastic sheet (20) which is arranged between the right side surface of the steel wire wheel (16) and the stepped shaft section mounting support (22) and is in a compression state, and a locking surface and a locking hole which can be matched with each other and enable the self-locking shaft section (18.1) to be locked in the self-locking shaft section mounting support (19) through the elasticity of the self-locking elastic sheet (20) are arranged on the self-locking shaft section (18.1) and the self-locking shaft section mounting support (19).

9. The intranasal endoscopic catheter structure with a sheath of soft and hard material as set forth in claim 8, wherein: the self-locking shaft section (18.1) comprises a frustum-shaped shaft section (21), and the diameter of the surface of one side, close to the steel wire wheel (16), of the frustum-shaped shaft section (21) is larger than the diameter of the surface of one side, far away from the steel wire wheel (16), of the frustum-shaped shaft section (21); the locking surface is a frustum-shaped side surface of the frustum-shaped shaft section (21), and the locking hole is a frustum-shaped hole arranged in the self-locking shaft section mounting support (19).

10. The intranasal endoscopic catheter structure with a sheath of soft and hard material as set forth in claim 8, wherein: the self-locking elastic sheet (20) is coaxially arranged on the stepped shaft section (18.2), one side surface of the self-locking elastic sheet (20) is in contact with the inner side surface of the stepped shaft section mounting support (22), and the other side surface of the self-locking elastic sheet is in contact with the right side surface of the steel wire wheel (16).

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