CN219397171U - Runner locking device and contain its medical endoscope - Google Patents

Abstract

The utility model discloses a rotating wheel locking device and a medical endoscope comprising the same, wherein the rotating wheel locking device comprises a deflector rod, a pressing piece and an elastic piece, the deflector rod is rotationally connected with a shell of the medical endoscope, and locking positions and unlocking positions are formed at two limit positions of the rotation of the deflector rod; the pressing piece is in sliding fit with the shell of the medical endoscope, one end of the pressing piece is abutted with the deflector rod, and the other end of the pressing piece is matched with the rotating wheel of the medical endoscope; the elastic piece is limited between the compressing piece and the shell along the translation direction of the compressing piece; when the deflector rod is in the locking position, the deflector rod extrudes the pressing piece, and the elastic piece deforms at the same time, so that the pressing piece is pressed to the surface of the rotating wheel; when the deflector rod is in the unlocking position, the elastic piece is reset, and the deflector rod is separated from the rotating wheel. According to the utility model, the elastic piece is arranged at the pressing piece, the pressing piece can reset by means of the acting force of the elastic piece at the moment of releasing the deflector rod, so that the deflector rod can reach an unlocking position, the rotating wheel can stably rotate, and the operation is more accurate.

Description

Runner locking device and contain its medical endoscope

Technical Field

The utility model relates to the technical field of medical instruments, in particular to a rotating wheel locking device and a medical endoscope comprising the same.

Background

Endoscopes are a commonly used medical device that includes a control end and an insertion assembly through which the insertion assembly is controlled to enter the body through a natural canal or surgically formed canal of the body. The control end controls the end of the insertion assembly to bend through the control rope, guides the insertion assembly to enter a human body, facilitates projecting each region inside the human body, comprises a shell, a control wheel located outside the shell and a rotating wheel located inside the shell, and drives the rotating wheel to rotate through the control wheel, so that the bending of the insertion assembly is controlled through the control rope connected with the rotating wheel.

In the prior art, the locking device is arranged at the control end to inhibit the rotation of the rotating wheel, so that the bending angle of the end part of the insertion assembly is fixed, wherein the locking device in the utility model patent with the patent number of CN212438544U has obvious structural advantages, the locking device directly applies acting force to the rotating wheel, no connection relation exists between the locking device and the control wheel, the locking function and the rotation function are implemented independently, and even if the locking device fails, the normal rotation of the rotating wheel is not influenced. However, the locking device has the advantages that the locking wheel component converts rotary motion into linear motion through a spiral contact surface mode, when the female locking wheel is in a locked state to an unlocked state, only the extrusion of the rotating wheel and the matching inertia of the spiral contact surface are relied on, no external reset force exists, when the friction force between the male locking wheel and the female locking wheel is increased or the locking device is switched to the unlocked state, the female locking wheel cannot be immediately reset to be completely attached to the end face of the male locking wheel, the rotation limit of the male locking wheel is not limited by the female locking wheel, the male locking wheel can be excessively rotated and cannot reach the unlocked state, in addition, the female locking wheel cannot be timely reset, namely the female locking wheel and the rotating wheel cannot be completely separated, the force is large when the control wheel is used for initial rotary operation, the endoscope insertion component is easy to swing, and the internal tissues of a patient can be damaged.

In summary, how to design a locking device capable of precisely controlling the locking and unlocking states is a technical problem to be solved at present.

Disclosure of Invention

The utility model provides a rotating wheel locking device and a medical endoscope comprising the same, which aim to solve the technical problems that an endoscope locking device in the prior art cannot realize immediate resetting of a female locking wheel when being released, so that the rotation angle is uncertain, even the stable rotation of a rotating wheel is influenced, and the internal tissues of a patient are damaged.

The utility model provides a rotating wheel locking device which comprises a deflector rod, a pressing piece and an elastic piece, wherein the deflector rod is rotationally connected with a shell of a medical endoscope, and locking positions and unlocking positions are formed at two limiting positions of the rotation of the deflector rod; the pressing piece is in sliding fit with the shell of the medical endoscope, one end of the pressing piece is abutted with the deflector rod, and the other end of the pressing piece is matched with the rotating wheel of the medical endoscope; the elastic piece is limited between the compressing piece and the shell along the translation direction of the compressing piece; when the deflector rod is in the locking position, the deflector rod extrudes the pressing piece, and the elastic piece deforms at the same time, so that the pressing piece is pressed to the surface of the rotating wheel; when the deflector rod is in the unlocking position, the elastic piece is reset, and the deflector rod is separated from the rotating wheel.

Further, the driving lever includes the pivot and with pivot fixed connection's pole portion, the pivot with the shell rotates to be connected, pole portion is including being close to the function end that the pivot set up and keeping away from the operation end that the pivot set up, the outer peripheral face and the clamp piece butt of function end, and the outer peripheral face of function end is unequal to the distance in pivot center.

Further, the outer peripheral surface of the functional end is circumferentially divided into a locking area and an unlocking area, the locking area is a plane which can be attached to the surface of the pressing piece, the unlocking area is an arc surface, and the distance from the locking area to the center of the rotating shaft is greater than the distance from the unlocking area to the center of the rotating shaft.

Further, the compressing piece comprises a compressing buckle abutted with the deflector rod and a compressing block fixed with the compressing buckle, the compressing block is matched with the surface of the rotating wheel, and a shoulder for limiting the elastic piece is arranged on the compressing buckle.

Further, the shoulder is located between the deflector rod and the elastic piece along the translation direction of the compression buckle.

Further, one end of the compaction block facing the rotating wheel is provided with elastic gaskets corresponding to the rotating wheels one by one.

Further, the contact surface of the elastic gasket and the rotating wheel is an arc surface.

Further, the compressing block comprises a connecting part for sleeving the elastic piece and a matching part matched with the rotating wheel, the center of the compressing block is provided with a mounting hole, the shoulder is positioned at one end of the connecting part, and the compressing buckle further comprises a buckle which passes through the mounting hole and is buckled with the matching part.

The utility model also provides a medical endoscope, which comprises a shell, a rotating wheel, a control wheel for driving the rotating wheel to rotate and the rotating wheel locking device, wherein the rotating wheel and the control wheel are both in rotating connection with the shell.

Further, the surface of the shell is provided with an operation hole for the deflector rod to extend out, and the shell is internally provided with a shaft hole for rotationally connecting the deflector rod and a limiting plate which is in sliding fit with the pressing piece and is used for limiting the elastic piece.

The beneficial effects of the utility model are as follows:

(1) According to the rotating wheel locking device and the medical endoscope comprising the same, the rotating motion of the deflector rod is converted into the linear motion of the pressing piece in a simple pressing mode, so that the motion distance of the deflector rod is reduced, meanwhile, the elastic piece is arranged at the pressing piece, the pressing piece can reset at the moment of release of the deflector rod by means of the acting force of the elastic piece, the pressing piece is rapidly separated from the rotating wheel, the deflector rod is pressed to be kept in the unlocking position, the deflector rod can be guaranteed to reach the unlocking position, the rotating wheel can stably rotate, and the operation is more accurate.

(2) According to the utility model, the radial position of the pressing piece is changed when the deflector rod is abutted with the pressing piece by virtue of the non-circular arrangement of the outer peripheral surface of the deflector rod functional end, so that the locking and unlocking functions are realized.

(3) The compressing piece provided by the utility model consists of the compressing buckle and the compressing block which are mutually buckled, and has the advantages of good structural stability and convenience in disassembly and assembly.

Drawings

The utility model will be further described with reference to the drawings and examples.

FIG. 1 is an internal schematic view of a specific embodiment of a medical endoscope according to the present utility model;

FIG. 2 is an enlarged view of FIG. 1 at a;

FIG. 3 is a cross-sectional view taken along A-A of FIG. 1;

FIG. 4 is an exploded view of an embodiment of a medical endoscope according to the present utility model;

FIG. 5 is a schematic view of an assembly of the wheel locking device of the present utility model;

fig. 6 is a schematic view of the structure of the locking member of the present utility model.

In the figure, 1, a rotating wheel locking device, 2, a deflector rod, 201, a rotating shaft, 202, a rod part, 2021, a functional end, 20211, a locking area, 20212, an unlocking area, 2022, an operating end, 3, a pressing piece, 301, a pressing buckle, 3011, a shoulder, 3012, a buckle, 302, a pressing block, 3021, a connecting part, 3022, a matching part, 3023, a mounting hole, 303, an elastic gasket, 4, an elastic piece, 5, a housing, 501, an operating hole, 502, a shaft hole, 503, a limiting plate, 6, a first rotating wheel, 7, a second rotating wheel, 8, an interface, 9, a spacing sheet, 10, a first control wheel, 11 and a second control wheel.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the utility model.

A rotating wheel locking device comprises a deflector rod 2, a pressing piece 3 and an elastic piece 4, wherein the deflector rod 2 is in rotary connection with a shell 5 of a medical endoscope, and a locking position and an unlocking position are formed at two limit positions of rotation of the deflector rod 2; the pressing piece 3 is in sliding fit with the shell 5 of the medical endoscope, one end of the pressing piece 3 is abutted with the deflector rod 2, and the other end of the pressing piece is matched with the rotating wheel of the medical endoscope; the elastic piece 4 is limited between the pressing piece 3 and the shell 5 along the translation direction of the pressing piece 3; when the deflector rod 2 is in the locking position, the deflector rod 2 presses the pressing piece 3, and the elastic piece 4 deforms at the same time, so that the pressing piece 3 presses the surface of the rotating wheel; when the deflector rod 2 is in the unlocking position, the elastic piece 4 is reset, and the deflector rod 2 is separated from the rotating wheel.

The shift lever 2 is a direct operation part of a user, performs rotary motion, the pressing part 3 is an execution part, performs linear motion along the radial direction of the rotating wheel, and the elastic part 4 stores energy when the shift lever 2 is in a locking position and releases energy to reset the pressing part 3 when the shift lever 2 is in an unlocking position. Compared with the prior art, the elastic piece 4 is additionally arranged, so that the compressing piece 3 is in a separated state with the rotating wheel in the unlocking state, the operation force can be more uniform when the control wheel is rotated at the moment, the swing of the inserting assembly can not be caused, the operation stability is better, and the damage to internal tissues of a patient is avoided.

In the utility model, the movement mode conversion of the deflector rod 2 and the pressing piece 3 can be realized in various modes, and the spiral end face fit or the thread fit and the like in the prior art are utilized, but the fit modes are flexible and poorer in movement, and the requirement on the manufacturing precision of the fit faces is higher, therefore, the utility model provides the following preferred embodiment:

example 1

As shown in fig. 2-6, a rotary locking device 1 includes a driving lever 2, a pressing member 3 and an elastic member 4, where the driving lever 2 includes a rotating shaft 201 and a lever portion 202 fixedly connected to the rotating shaft 201, the rotating shaft 201 is rotationally connected to a housing 5, the lever portion 202 includes a functional end 2021 disposed close to the rotating shaft 201 and an operating end 2022 disposed far away from the rotating shaft 201, an outer circumferential surface of the functional end 2021 abuts against the pressing member 3, and a distance from the outer circumferential surface of the functional end 2021 to a center of the rotating shaft 201 is unequal, i.e., an outer circumferential surface of the functional end 2021 is a non-circular surface, at this time, an abutting surface of the pressing member 3 may be a simple plane, and when a position of the rotating shaft 201 is unchanged, a distance from the outer circumferential surface of the functional end 2021 to the center of the rotating shaft 201 is unequal, i.e., a radial position of the pressing member 3 is different, so that radial reciprocating movement of the pressing member 3 is achieved through rotation of the driving lever 2 and sliding fit between the housing 5 and the pressing member 3.

The locking position of the deflector rod 2 means that the distance from the surface of the functional end 2021 abutting against the pressing piece 3 to the center of the rotating shaft 201 is the largest at this time, and under the condition that the position of the rotating shaft 201 is unchanged, the pressing piece 3 is pressed in the radial direction to the direction of the rotating wheel to lock the rotating wheel; the unlocking position of the deflector rod 2 means that the distance from the surface of the functional end 2021 abutting against the pressing piece 3 to the center of the rotating shaft 201 is the smallest, the deflector rod 2 does not have extrusion force on the pressing piece 3, the pressing piece 3 leaves the surface of the rotating wheel under the action of the elastic piece 4, and the rotating wheel can rotate freely.

In this embodiment, the cooperation mode of driving lever 2 and compress tightly piece 3 is simple, does not need accurate terminal surface cooperation, only needs the linear motion of compressing tightly piece 3 to driving lever 2 tip non-round face design can be realized, and the motion flexibility of driving lever 2 and compressing tightly piece 3 is higher, and the operation feel is better.

More specifically, the outer peripheral surface of the functional end 2021 is circumferentially divided into a locking region 20211 and an unlocking region 20212 (as shown in fig. 3), the locking region 20211 is a plane that can be attached to the surface of the pressing member 3, the unlocking region 20212 is an arc surface, and the distance from the locking region 20211 to the center of the rotating shaft 201 is greater than the distance from the unlocking region 20212 to the center of the rotating shaft 201. When the locking area 20211 of the deflector rod 2 is abutted against the pressing piece 3, the rotating wheel is in a locking state, and the deflector rod 2 has extrusion force on the pressing piece 3 at the moment, the plane type locking area 20211 can enable the deflector rod 2 to be in plane fit contact with the pressing piece 3, so that the locking state is kept stable, and locking failure caused by shaking of an endoscope is avoided. When the unlocking area 20212 of the deflector rod 2 is abutted with the pressing piece 3, the rotating wheel is in an unlocking state, and at the moment, the pressing piece 3 presses the deflector rod 2 under the action of the elastic piece 4, and the deflector rod 2 is a stressed piece, so that the unlocking area 20212 can not adopt a planar structure, and the arrangement of the arc surface unlocking area 20212 can facilitate the rotation of the deflector rod 2.

Example two

On the basis of the first embodiment, the compressing piece 3 adopts a split design, is convenient to process, saves maintenance cost, and as shown in fig. 5 and 6, the compressing piece 3 comprises a compressing buckle 301 abutted with the deflector rod 2 and a compressing block 302 fixed with the compressing buckle 301, the compressing block 302 is matched with the surface of the rotating wheel, and a shoulder 3011 for limiting the elastic piece 4 is arranged on the compressing buckle 301. The fixed connection of the compression buckle 301 and the compression block 302 comprises detachable fixation and non-detachable fixation, and preferably adopts detachable fixation connection, specifically, the compression block 302 comprises a connecting portion 3021 for sleeving an elastic piece 4 and a matching portion 3022 matched with a rotating wheel, the matching portion 3022 is attached to the rotating wheel, therefore, the matching portion 3022 is an arc-shaped block, the connecting portion 3021 is of a hollow columnar structure, a mounting hole 3023 is formed in the center of the compression block 302, a shoulder 3011 is located at one end of the connecting portion 3021 and is used for being abutted to the end portion of the elastic piece 4, and the compression buckle 301 further comprises a buckle 3012 buckled with the matching portion 3022 through the mounting hole 3023, so that the compression buckle 301 is fixed to the compression block 302.

In the present utility model, the deformation of the elastic member 4 may be tensile deformation or compressive deformation, and if the elastic member is tensile deformation, both ends of the elastic member 4 need to be fixedly connected with the pressing member 3 and the housing 5, respectively, and when the pressing member 3 approaches the rotating wheel, the distance between the pressing member 3 connected with the elastic member 4 and the housing 5 increases, so that the elastic member 4 is stretched, and at this time, the elastic member 4 is usually a spring. If the elastic piece 4 is deformed by compression, the two ends of the elastic piece 4 only need to be abutted against the pressing piece 3 and the shell 5, when the pressing piece 3 approaches to the rotating wheel, the distance between the pressing piece 3 connected with the elastic piece 4 and the shell 5 is reduced, so that the elastic piece 4 is compressed, and at the moment, the elastic piece 4 can be a spring or a reed, and the options are more.

In this embodiment, the shoulder 3011 is located between the lever 2 and the elastic member 4 along the translation direction of the pressing buckle 301, when the lever 2 presses the pressing member 3, the shoulder 3011 presses the elastic member 4, so that the elastic member 4 is shrunk and deformed, and two ends of the elastic member 4 do not need to be fixed with the shoulder 3011 and the housing 5. As shown in fig. 1 and 2, in the use state, the wheel locking device 1 is arranged at the top of the housing 5 (above the rotating wheel), that is, the shoulder 3011 is located at the upper end of the elastic member 4, so that the housing 5 abuts against the lower end of the elastic member 4, and the shoulder 3011 moves downward to press the elastic member 4, otherwise, the shoulder 3011 can rebound upward under the action of the elastic member 4.

Preferably, one end of the pressing block 302 facing the rotating wheel is provided with elastic gaskets 303 corresponding to the rotating wheel one by one, and the elastic gaskets 303 have elastic force, so that the impact force between the pressing block 302 and the rotating wheel can be reduced, and the impact noise can be reduced.

Since the outer circumferential surface of the rotating wheel is an arc surface, the contact surface between the elastic pad 303 and the rotating wheel is preferably an arc surface, so that the contact area between the elastic pad 303 and the rotating wheel can be increased, and the locking effect can be improved.

Example III

The medical endoscope comprises a shell 5, a rotating wheel, a control wheel for driving the rotating wheel to rotate and the rotating wheel locking device 1, wherein the rotating wheel and the control wheel are both in rotary connection with the shell 5.

The structural principle of the medical endoscope for controlling the bending of the end part of the insertion component is the same as that of the prior art, and the utility model is not shown in the schematic drawing and only briefly described. The shell 5 is formed by the cover of left half shell and right half shell, the upper portion of shell 5 is the disc, inside sets up the rotation wheel, the lower part shrink of shell 5 forms the interface 8 with the pipe intercommunication, the terminal of pipe is flexible snake bone, the control wheel is user's direct operation part, it is rotatory to drive the rotation wheel through the control wheel, the one end of two traction wires is connected to rotation wheel both sides, flexible snake bone is connected to the other end of two traction wires, rotatory rotation wheel, the traction wire of rotation wheel one side rises, drive one side of flexible snake bone and lift, the traction wire of rotation wheel other end then descends, along with the axial extension of two traction wires along the pipe, the tip of traction flexible snake bone is crooked towards different directions.

The present embodiment also has two rotating wheels and two control wheels, which are respectively named as a first rotating wheel 6, a second rotating wheel 7, a first control wheel 10 and a second control wheel 11, as shown in fig. 1 and 2, the two control wheels are located outside the housing 5, the two rotating wheels are located inside the housing 5, the first control wheel 10 drives the first rotating wheel 6 to rotate, the second control wheel 11 drives the second rotating wheel 7 to rotate, the first control wheel 10 and the first rotating wheel 6 are located at the two ends in the axial direction, the second control wheel 11 and the second rotating wheel 7 are sleeved on the rotating shaft of the first rotating wheel 6, and a spacer 9 is arranged between the first rotating wheel 6 and the second rotating wheel 7 to avoid friction collision between the two.

For the wheel locking device 1 according to the present utility model, the housing 5 is also provided with a unique design, in this embodiment, the surface of the housing 5 is provided with an operation hole 501 for extending the driving lever 2, and the housing 5 is provided with a shaft hole 502 for rotationally connecting the driving lever 2 and a limiting plate 503 slidingly engaged with the pressing member 3 and used for limiting the elastic member 4. As shown in fig. 2 and 3, a shaft hole 502 is formed in each of the left half shell and the right half shell of the housing 5, the rotary shaft 201 of the lever 2 extends to both sides of the lever portion 202, and when the lever is mounted, both ends of the rotary shaft 201 of the lever 2 are respectively inserted into the two shaft holes 502, and the lever portion 202 extends from the operation hole 501. The limiting plate 503 is located below the operation hole 501, the limiting plate 503 may be connected with the housing 5 through two side plates to form a cavity, the pressing buckle 301 passes through the limiting plate 503 and is slidably matched with the limiting plate 503, the shoulder 3011 and the elastic member 4 of the pressing buckle 301 are located in the cavity, and the matching portion 3022 of the pressing block 302 is located below the limiting plate 503, and since two rotating wheels are provided, two elastic gaskets 303 in the embodiment are correspondingly provided.

In the description of the present utility model, it should be understood that the terms "center," "upper," "lower," "inner," "outer," "axial," "radial," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present utility model and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In this specification, a schematic representation of the terms does not necessarily refer to the same embodiment. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments.

With the above-described preferred embodiments according to the present utility model as an illustration, the above-described descriptions can be used by persons skilled in the relevant art to make various changes and modifications without departing from the scope of the technical idea of the present utility model. The technical scope of the present utility model is not limited to the description, but must be determined according to the scope of claims.

Claims (10)

1. A wheel locking device comprising:

the deflector rod (2) is rotationally connected with the shell (5) of the medical endoscope, and a locking position and an unlocking position are formed at two limit positions of rotation of the deflector rod (2);

the pressing piece (3) is in sliding fit with the shell (5) of the medical endoscope, one end of the pressing piece (3) is abutted with the deflector rod (2), and the other end of the pressing piece is matched with the rotating wheel of the medical endoscope;

an elastic member (4) which is limited between the pressing member (3) and the housing (5) along the translational direction of the pressing member (3); when the deflector rod (2) is in a locking position, the deflector rod (2) presses the pressing piece (3), and meanwhile the elastic piece (4) deforms, so that the pressing piece (3) is pressed to the surface of the rotating wheel; when the deflector rod (2) is in an unlocking position, the elastic piece (4) is reset, and the deflector rod (2) is separated from the rotating wheel.

2. The wheel locking device of claim 1, wherein: the driving lever (2) comprises a rotating shaft (201) and a lever part (202) fixedly connected with the rotating shaft (201), the rotating shaft (201) is rotationally connected with the housing (5), the lever part (202) comprises a functional end (2021) which is close to the rotating shaft (201) and an operating end (2022) which is far away from the rotating shaft (201), the outer peripheral surface of the functional end (2021) is abutted with the pressing piece (3), and the distance from the outer peripheral surface of the functional end (2021) to the center of the rotating shaft (201) is unequal.

3. The wheel locking device of claim 2, wherein: the outer peripheral surface of the functional end (2021) is circumferentially divided into a locking area (20211) and an unlocking area (20212), the locking area (20211) is a plane which can be attached to the surface of the pressing piece (3), the unlocking area (20212) is an arc surface, and the distance from the locking area (20211) to the center of the rotating shaft (201) is greater than the distance from the unlocking area (20212) to the center of the rotating shaft (201).

4. The wheel locking device of claim 1, wherein: the pressing piece (3) comprises a pressing buckle (301) which is abutted with the deflector rod (2) and a pressing block (302) which is fixed with the pressing buckle (301), the pressing block (302) is matched with the surface of the rotating wheel, and the pressing buckle (301) is provided with a shoulder (3011) for limiting the elastic piece (4).

5. The wheel locking device of claim 4, wherein: the shoulder (3011) is located between the deflector rod (2) and the elastic piece (4) along the translation direction of the pressing buckle (301).

6. The wheel locking device of claim 4, wherein: one end of the compaction block (302) facing the rotating wheel is provided with elastic gaskets (303) corresponding to the rotating wheels one by one.

7. The wheel locking device of claim 6, wherein: the contact surface of the elastic gasket (303) and the rotating wheel is an arc surface.

8. The wheel locking device of claim 4, wherein: the compressing block (302) comprises a connecting portion (3021) for sleeving the elastic piece (4) and a matching portion (3022) matched with the rotating wheel, a mounting hole (3023) is formed in the center of the compressing block (302), the shoulder (3011) is located at one end of the connecting portion (3021), and the compressing buckle (301) further comprises a buckle (3012) which penetrates through the mounting hole (3023) and is buckled with the matching portion (3022).

9. A medical endoscope, characterized in that: comprising a housing (5), a rotating wheel, a control wheel for driving the rotating wheel in rotation and a wheel locking device (1) according to any one of claims 1-8, both said rotating wheel and control wheel being in rotational connection with the housing (5).

10. The medical endoscope according to claim 9, wherein: the surface of the shell (5) is provided with an operation hole (501) for the deflector rod (2) to extend out, and the shell (5) is internally provided with a shaft hole (502) which is rotationally connected with the deflector rod (2) and a limiting plate (503) which is in sliding fit with the pressing piece (3) and is used for limiting the elastic piece (4).