CN117338236A

CN117338236A - Intelligent imaging detection equipment for orbital diseases

Info

Publication number: CN117338236A
Application number: CN202311510376.2A
Authority: CN
Inventors: 陈露; 朱颖
Original assignee: Xiangya Hospital of Central South University
Current assignee: Xiangya Hospital of Central South University
Priority date: 2023-11-13
Filing date: 2023-11-13
Publication date: 2024-01-05

Abstract

The invention relates to the technical field of ophthalmic detection equipment, in particular to intelligent imaging detection equipment for orbital diseases, which comprises: the machine body is provided with a bracket; the bearing mechanism is arranged at the bottom of the bracket and used for bearing the head; the binocular shooting mechanism is arranged at the top of the bracket and is used for shooting a plurality of groups of eye photos; the automatic overturning shielding mechanism is arranged at the top of the support and close to the inner side of the binocular shooting mechanism and used for alternately shielding two eyes, the machine body is also provided with a computer used for receiving and processing a plurality of groups of eye photos and displaying the processed information, the support is provided with nostrils, and the nostrils are positioned above the supporting mechanism.

Description

Intelligent imaging detection equipment for orbital diseases

Technical Field

The invention relates to the technical field of ophthalmic detection equipment, in particular to intelligent imaging detection equipment for orbital diseases.

Background

Orbital diseases refer to diseases affecting the structure and function of the orbit, including orbital tumors, orbital inflammation, orbital deformity, etc., which may cause serious problems such as vision impairment, protrusion of eyeballs, drooping eyelids, etc., and seriously affect the quality of life of patients.

Conventional orbital disease diagnosis typically requires the experience of a physician and a series of examination means such as eye position, eye movement examination, eye protrusion examination, eyelid cleavage height, MRD value (distance from central reflex of the cornea to the eyelid margin) examination, CT or magnetic resonance scan, etc., however, these methods have problems such as requiring a specialized doctor, complicated operation, long time consumption, high cost, etc.

In order to solve these problems, an intelligent imaging detection apparatus has been developed, which can rapidly and accurately identify and detect orbital diseases using advanced imaging technologies such as computer vision, artificial intelligence, etc., and firstly, the intelligent imaging detection apparatus can acquire images and videos of eyes of a patient through a high definition camera, then, analyze and process the images and videos using computer vision technology, and through a deep learning algorithm, the apparatus can automatically identify characteristics of orbital diseases such as protrusion of eyeballs, abnormal eye position, abnormal eyelid fissure height, etc., and at the same time, the apparatus can track and analyze eye ball movements to evaluate the movement functions of eyeballs.

In addition, intelligent imaging check out test set still can be connected with medical database, acquires a large amount of orbital disease data and clinical experience, through training and the study of artificial intelligence algorithm, the equipment can constantly promote self diagnosis accuracy and efficiency.

In a word, the intelligent imaging detection equipment for the orbital diseases can rapidly and accurately identify and detect the orbital diseases by utilizing advanced imaging technology and artificial intelligent algorithm, the occurrence of the equipment can greatly improve the diagnosis efficiency of the orbital diseases, lighten the workload of doctors and simultaneously provide better medical services for patients.

At present, the existing intelligent imaging detection equipment has the following problems when in use: 1. the head of the patient lacks support, which easily causes the neck ache of the patient in the detection process and causes discomfort; or measurement inaccuracy due to positional variation; 2. when shooting different parts of the eyes, a plurality of cameras are needed, the cost is increased, and the camera can only prompt a patient to look at different directions through voice, has no obvious fixation direction indication function, and is inconvenient to use for some patients with unclear direction resolution; 3. when eyes are detected, the patient is required to open and close one eye, and the use limitation is also very large for some patients with eye diseases and difficult control of the eyes. 4. Specific numerical values such as the abrupt eye degree and the eyeball movement amplitude of a patient cannot be calculated autonomously, whether the numerical values are abnormal or not cannot be judged autonomously, and medical treatment is suggested.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides intelligent imaging detection equipment for orbital diseases, which has the advantages of improving the detection comfort level of patients, having high detection accuracy, actively guiding the fixation azimuth and actively shielding eyes, and solves the problems in the prior art.

In order to solve the technical problems, the invention provides the following technical scheme: comprising the following steps:

the machine body is provided with a bracket;

the bearing mechanism is arranged at the bottom of the bracket and used for bearing the head;

the binocular shooting mechanism is arranged at the top of the bracket and is used for shooting a plurality of groups of eye photos;

the self-overturning shielding mechanism is arranged at the top of the bracket and close to the inner side of the binocular shooting mechanism and used for alternately shielding two eyes.

Preferably, the machine body is also provided with a computer for receiving and processing a plurality of groups of eye photos and displaying the processed information.

Preferably, the support is provided with nostrils, and the nostrils are positioned above the supporting mechanism.

Preferably, the supporting mechanism comprises a bracket movably connected to the bottom of the bracket, an adjusting screw is connected to the back of the bracket in a spiral transmission manner, the bottom end of the adjusting screw is rotatably connected with the bottom of the bracket, and a sponge supporting pad is further fixedly arranged on the bracket.

Preferably, the binocular shooting mechanism comprises a guide rail arranged at the top of the support, a first motor is arranged at one end of the guide rail, an output shaft of the first motor is fixedly connected with one end of a linear screw rod, the linear screw rod is rotationally connected in the guide rail, a sliding block which is arranged on the guide rail in a sliding manner is connected to the linear screw rod in a spiral transmission manner, an electric rotating table is arranged at the top of the sliding block, a rotating shaft of the electric rotating table is fixedly connected with one end of a connecting frame, a fixing frame is fixedly arranged at the other end of the connecting frame, a camera is arranged in the fixing frame, and a fixation azimuth indicating assembly is arranged on the front surface of the camera.

Preferably, a linkage toothed plate is fixedly arranged at the bottom of the sliding block.

Preferably, the fixing orientation indicating assembly comprises a second motor arranged on the front face of the camera, a column gear is fixedly connected to an output shaft of the second motor, the column gear is meshed with a toothed ring, the toothed ring is rotationally connected to a fixed ring, the fixed ring is fixedly connected to the front face of the camera, an extension arm is fixedly arranged on an outer ring of the toothed ring, and a plurality of indicator lamps are fixedly arranged on the front face of the extension arm at equal intervals.

Preferably, the self-overturning shielding mechanism comprises a fixing frame installed at the top of the support, a first bearing frame is fixedly arranged on the inner side of the fixing frame, a first worm shaft is connected to the first bearing frame in a rotating mode, the bottom end of the first worm shaft is meshed with the first worm gear, the first worm gear is fixedly connected to the middle of the transmission shaft, bevel gears are fixedly connected to the two ends of the transmission shaft, the first bevel gear is meshed with the second bevel gear, the second bevel gear is fixedly connected to one end of the second worm shaft, the transmission shaft and the second worm shaft are connected to one side of the fixing frame in a rotating mode through the second bearing frame, a second worm gear is arranged above the second worm shaft and meshed with the second worm gear, a shielding plate is fixedly arranged on the outer wall of the rotating drum, the rotating drum is connected to the outer wall of the fixed cross rod, and the fixed cross rod is fixedly connected to the bottom of the fixing frame.

Preferably, a linkage gear which is positioned on the same horizontal plane with the linkage toothed plate is fixedly arranged at the top end of the first worm shaft, and the linkage gear is meshed with the linkage toothed plate.

By means of the technical scheme, the invention provides intelligent imaging detection equipment for orbital diseases, which has at least the following beneficial effects:

1. this orbital disease intelligent imaging detection equipment through setting up bearing mechanism, can support patient's head, alleviates neck burden, and support height-adjustable, can use the patient of different head sizes.

2. According to the intelligent imaging detection equipment for the orbital diseases, the positions of the cameras can be translated and rotated by arranging the binocular shooting mechanism, so that different positions and more eye photos of eyes can be shot, and the binocular detection accuracy is improved.

3. This orbital disease intelligent imaging detection equipment through setting up admittedly to position indication subassembly, can initiatively guide the patient to each position look, has admittedly to position indication function according to the position of a plurality of pilot lamps on the extension arm, and a plurality of pilot lamps can be by near to far single light, can guide the patient to see the far and near degree to each position.

4. This orbital disease intelligent imaging detection equipment through setting up from upset shielding mechanism, can form the linkage with the motion of camera, and the camera removes to which side, and the shielding plate of this side just turns over, and the shielding plate of opposite side just is in shielding state, can initiatively block one of them eye of patient to detect work to another eye.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application:

FIG. 1 is a schematic view of the overall three-dimensional structure of the present invention;

FIG. 2 is a schematic view of the front of the components of the bracket of the present invention;

FIG. 3 is a schematic view of the structure of the back of each component of the bracket of the present invention;

FIG. 4 is a schematic view of the structure of the support mechanism of the present invention;

FIG. 5 is a schematic view of the self-tilting shielding mechanism of the present invention;

FIG. 6 is a schematic diagram of a binocular shooting mechanism of the present invention;

FIG. 7 is a schematic view of the structure of the bottom linkage toothed plate of the slider of the present invention;

FIG. 8 is a schematic view of the front face of the camera of the present invention;

fig. 9 is a schematic structural view of the fixation orientation indicating assembly of the present invention.

Reference numerals:

100. a body; 101. a computer;

200. a bracket; 201. out of nostril;

300. a bearing mechanism; 301. a bracket; 302. adjusting a screw; 303. a sponge support cushion;

400. a binocular shooting mechanism; 401. a guide rail; 402. a first motor; 403. a linear screw; 404. a slide block; 405. an electric rotating table; 406. a connecting frame; 407. a fixed frame; 408. a camera; 409. a fixation azimuth indication component; 4091. a second motor; 4092. a post gear; 4093. a toothed ring; 4094. a fixing ring; 4095. an extension arm; 4096. an indicator light; 410. a linkage toothed plate;

500. a self-turning shielding mechanism; 501. a fixing frame; 502. a bearing bracket I; 503. a worm shaft I; 504. a linkage gear; 505. a first worm wheel; 506. a transmission shaft; 507. bevel gears I; 508. bevel gears II; 509. a bearing bracket II; 510. a worm shaft II; 511. a second worm wheel; 512. a rotating drum; 513. a shielding plate; 514. and fixing the cross bar.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The following describes an intelligent imaging detection device for orbital diseases according to some embodiments of the invention with reference to the accompanying drawings.

Embodiment one:

1-9, the intelligent imaging detection device for orbital diseases provided by the invention comprises:

and a body 100, wherein a bracket 200 is mounted on the body 100.

And a supporting mechanism 300, wherein the supporting mechanism 300 is installed at the bottom of the bracket 200 and is used for supporting the head.

The binocular shooting mechanism 400 is installed at the top of the bracket 200, and is used for shooting a plurality of groups of eye photos.

The self-tilting shielding mechanism 500 is installed at the top of the bracket 200 near the inner side of the binocular shooting mechanism 400, and is used for alternately shielding two eyes.

Further, the machine body 100 is further provided with a computer 101 for receiving and processing a plurality of groups of eye photos and displaying the processed information.

Further, the support 200 is provided with an nostril 201, the nostril 201 is located above the supporting mechanism 300, and when the head of the patient is supported, the nose is just located in the nostril 201, so that the nose is prevented from being blocked.

Further, the binocular shooting mechanism 400 includes a guide rail 401 mounted on the top of the bracket 200, a first motor 402 is mounted at one end of the guide rail 401, an output shaft of the first motor 402 is fixedly connected with one end of a linear screw 403, the linear screw 403 is rotatably connected in the guide rail 401, a slider 404 slidably disposed on the guide rail 401 is spirally connected to the linear screw 403, an electric rotating table 405 is mounted on the top of the slider 404, a rotating shaft of the electric rotating table 405 is fixedly connected with one end of a connecting frame 406, a fixed frame 407 is fixedly arranged at the other end of the connecting frame 406, a camera 408 is mounted in the fixed frame 407, and a fixation azimuth indicating assembly 409 is arranged on the front surface of the camera 408.

According to the embodiment, the supporting mechanism 300 is used to support the head of the patient, then the two eyes of the patient just face the position of the front self-turning shielding mechanism 500, the first motor 402 is started to work and drive the linear screw 403 to rotate, the linear screw 403 drives the linear screw to horizontally move under the spiral transmission action of the slide block 404, the slide block 404 drives the camera 408 to move to one side through the connecting frame 406, so that the eyes on the side can be photographed, and at the same time, the electric rotating table 405 can be started and the camera 408 can be driven to rotate, so that the camera 408 can rotate around the eyes, and the eyes can be photographed more comprehensively.

Embodiment two:

referring to fig. 2, 3 and 4, on the basis of the first embodiment, the supporting mechanism 300 includes a bracket 301 movably connected to the bottom of the bracket 200, an adjusting screw 302 is screwed on the back of the bracket 301, the bottom end of the adjusting screw 302 is rotatably connected to the bottom of the bracket 200, and a sponge supporting pad 303 is further fixed on the bracket 301.

According to the embodiment, the height of the bracket 301 can be adjusted by using the adjusting screw 302, so that eyes of patients with different head sizes can accurately align to the position of the camera 408, the chin of the head of the patient can be supported on the bracket 301 after the height is adjusted, and the comfort level of the head support can be improved by using the sponge supporting pad 303.

Embodiment III:

referring to fig. 6, 8 and 9, on the basis of the first embodiment, the fixing position indicating assembly 409 includes a second motor 4091 mounted on the front face of the camera 408, a post gear 4092 is fixedly connected to an output shaft of the second motor 4091, the post gear 4092 is meshed with a toothed ring 4093, the toothed ring 4093 is rotatably connected to a fixed ring 4094, the fixed ring 4094 is fixedly connected to the front face of the camera 408, an extension arm 4095 is fixedly arranged on an outer ring of the toothed ring 4093, and a plurality of indicator lamps 4096 are fixedly arranged on the front face of the extension arm 4095 at equal intervals.

According to the embodiment, the camera 408 starts the motor two 4091 and drives the extension arm 4095 to rotate under the meshing action of the pillar gear 4092 and the toothed ring 4093 in the process of taking the eye photo, the indicator 4096 on the extension arm 4095 is turned on, so that the patient can be actively guided to see the turned-on directions of the indicator 4096, the eyeballs of the patient can move to different ranges so as to take photos of various eyeball positions, the computer 101 can accurately judge the illness state, and meanwhile, the indicator 4096 on the extension arm 4095 can be turned on from near to far, so that the patient can be guided to see the distance of each direction.

Embodiment four:

referring to fig. 2, 3 and 5, on the basis of the first embodiment, the self-turning shielding mechanism 500 includes a fixing frame 501 installed on the top of the support 200, a first bearing frame 502 is fixedly disposed on the inner side of the fixing frame 501, a first worm shaft 503 is rotatably connected to the first bearing frame 502, the bottom end of the first worm shaft 503 is meshed with a first worm gear 505, the first worm gear 505 is fixedly connected to the middle of the transmission shaft 506, two ends of the transmission shaft 506 are fixedly connected with a first bevel gear 507, the first bevel gear 507 is meshed with a second bevel gear 508, the second bevel gear 508 is fixedly connected to one end of the second worm shaft 510, the transmission shaft 506 and the second worm shaft 510 are rotatably connected to one side of the fixing frame 501 through a second bearing frame 509, a second worm gear 511 is disposed above the second worm shaft 510 and meshed with the second worm gear 511, the second worm gear 511 is fixedly connected to one end of the second rotary drum 512, a shielding plate 513 is fixedly disposed on the outer wall of the rotary drum 512, the rotary drum 512 is rotatably connected to the outer wall of the fixing cross bar 514, and the fixing cross bar 514 is fixedly connected to the bottom of the fixing frame 501.

Specifically, the bottom of the slider 404 is fixedly provided with a linkage toothed plate 410, which can form a meshing action with the linkage gear 504, so as to provide power for the movement of the self-turning shielding mechanism 500.

Further, a linkage gear 504 on the same horizontal plane as the linkage toothed plate 410 is fixedly arranged at the top end of the first worm shaft 503, and the linkage gear 504 is meshed with the linkage toothed plate 410, so as to have the same effect as the arrangement effect of the linkage toothed plate 410.

According to the embodiment, when the binocular shooting mechanism 400 moves, the first worm shaft 503 is driven to rotate by the meshing action of the linkage toothed plate 410 and the linkage gear 504, the first worm shaft 503 drives the transmission shaft 506 to rotate by the meshing action of the first worm gear 505, the transmission shaft 506 drives the second worm shaft 510 on two sides to rotate by the meshing action of the first bevel gear 507 and the second bevel gear 508, the second worm shaft 510 drives the shielding plates 513 on two sides to rotate reversely by the meshing action of the second worm gear 511, the principle of the opposite rotation of the shielding plates 513 on two sides is based on the change of the transmission directions of the first bevel gear 507 and the second bevel gear 508 on two sides of the transmission shaft 506, when the shielding plates 513 on one side are put down, the shielding plates 513 on the other side can be opened, and the opened side of the shielding plates 513 is kept synchronous with the one side of the movement direction of the camera 408, so that the camera 408 can shoot two eyes respectively, and the opened shielding plates 513 cannot fall down even if the linkage toothed plate 410 is separated from the linkage gear 504 due to the self-locking force of the worm and the worm gear.

The specific operation process of the device can be known from the embodiment:

the height of the bracket 301 is firstly adjusted by the adjusting screw 302, so that eyes of patients with different head sizes can accurately reach the position of the camera 408, after the height adjustment, the chin of the head of the patient can be supported on the bracket 301, comfort level of the head can be improved by the sponge supporting pad 303, then the eyes of the patient just face to the position of the shielding plate 513, the first motor 402 is started to work and drive the linear screw 403 to rotate, the linear screw 403 is driven to horizontally move by the spiral transmission function of the sliding block 404, the sliding block 404 drives the camera 408 to move to one side by the connecting frame 406, thereby shooting the eyes of the side, meanwhile, when the binocular shooting mechanism 400 moves, the first worm gear shaft 503 is driven to rotate by the meshing function of the linkage toothed plate 410 and the linkage gear 504, the first worm gear shaft 503 drives the transmission shaft 506 to rotate by the meshing function of the first worm gear shaft 507 and the second worm gear shaft 510, the second worm shaft 510 drives the two side shielding plates 513 to reversely rotate by the meshing function of the two side by the two worm gears 513, when the shielding plate 513 on one side is put down, the motor 513 on the other side drives the side of the worm gear 513 is driven to move to one side, the camera 408 can rotate around the extending arm 408, the rotating around the rotating shaft 408, the camera is started to rotate, the camera 408 can rotate, the camera is started to rotate around the eye 408, the rotating side of the camera is completely, and the camera is started, the camera is started to rotate, the camera is positioned around the eye 408 is completely, and the camera is completely rotates, and the camera is completely can rotate, and the camera is simultaneously, and the camera is positioned, and the camera is completely can is completely and can be turned by the camera and can, and can be turned by the camera and has a camera and can be turned, and can be turned by a camera and a camera-95. The patient can be actively guided to see the direction in which the indicator 4096 is lighted, so that the eyeballs of the patient can move to different ranges, and thus, the computer 101 can conveniently and accurately judge the illness state, meanwhile, the plurality of indicator 4096 on the extension arm 4095 can be singly lighted from the near to the far, so that the patient can be guided to see the far and near degree of each direction, after the camera 408 shoots a plurality of groups of double-eye photos, photo data are transmitted into the computer 101, the computer 101 receives and processes a plurality of groups of eye photos, and the patient suffering from thyroid-related eye diseases, strabismus, orbit tumors and other diseases can be screened according to the eyeball protrusion degree, eyelid position, eyeball position and the like, and finally, the patient is recommended to visit a hospital.

It should be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. An orbital disease intelligent imaging detection device, comprising:

a machine body (100), wherein a bracket (200) is installed on the machine body (100);

the bearing mechanism (300) is arranged at the bottom of the bracket (200) and used for bearing the head;

the binocular shooting mechanism (400) is arranged at the top of the bracket (200) and is used for shooting a plurality of groups of eye photos;

the self-overturning shielding mechanism (500) is arranged at the top of the bracket (200) and close to the inner side of the binocular shooting mechanism (400) and used for alternately shielding two eyes.

2. The intelligent imaging detection apparatus for orbital diseases according to claim 1, wherein the machine body (100) is further provided with a computer (101) for receiving and processing a plurality of sets of eye photos and displaying the processed information.

3. The intelligent imaging detection device for orbital diseases according to claim 1, wherein the support (200) is provided with an outlet nostril (201), and the outlet nostril (201) is located above the bearing mechanism (300).

4. The intelligent imaging detection device for orbital diseases according to claim 1, wherein the bearing mechanism (300) comprises a bracket (301) movably connected to the bottom of the bracket (200), an adjusting screw (302) is connected to the back of the bracket (301) in a spiral transmission manner, the bottom end of the adjusting screw (302) is rotatably connected to the bottom of the bracket (200), and a sponge supporting pad (303) is further fixedly arranged on the bracket (301).

5. The intelligent imaging detection device for orbital diseases according to claim 1, wherein the binocular shooting mechanism (400) comprises a guide rail (401) installed at the top of the bracket (200), a motor I (402) is installed at one end of the guide rail (401), an output shaft of the motor I (402) is fixedly connected with one end of a linear screw (403), the linear screw (403) is rotationally connected in the guide rail (401), a sliding block (404) which is slidably arranged on the guide rail (401) is connected on the linear screw (403) in a spiral transmission manner, an electric rotating table (405) is installed at the top of the sliding block (404), a rotating shaft of the electric rotating table (405) is fixedly connected with one end of a connecting frame (406), a fixed frame (407) is fixedly arranged at the other end of the connecting frame (406), a camera (408) is installed in the fixed frame (407), and a fixation azimuth indicating assembly (409) is arranged on the front of the camera (408).

6. The intelligent imaging detection device for orbital diseases according to claim 5, wherein a linkage toothed plate (410) is fixedly arranged at the bottom of the slider (404).

7. The intelligent imaging detection device for orbital diseases according to claim 5, wherein the fixation azimuth indicating assembly (409) comprises a motor II (4091) arranged on the front face of the camera (408), a column gear (4092) is fixedly connected to an output shaft of the motor II (4091), the column gear (4092) is meshed with a toothed ring (4093), the toothed ring (4093) is rotatably connected to a fixed ring (4094), the fixed ring (4094) is fixedly connected to the front face of the camera (408), an extension arm (4095) is fixedly arranged on an outer ring of the toothed ring (4093), and a plurality of indicator lamps (4096) are fixedly arranged on the front face of the extension arm (4095) at equal intervals.

8. The intelligent imaging detection device for orbital diseases according to claim 6, wherein the self-turning shielding mechanism (500) comprises a fixing frame (501) installed at the top of the bracket (200), a first bearing frame (502) is fixedly arranged on the inner side of the fixing frame (501), a first worm shaft (503) is rotatably connected to the first bearing frame (502), the bottom end of the first worm shaft (503) is meshed with a first worm wheel (505), the first worm wheel (505) is fixedly connected to the middle part of a transmission shaft (506), bevel gears (507) are fixedly connected to two ends of the transmission shaft (506), the first bevel gears (507) are meshed with a second bevel gear (508), the second bevel gears (508) are fixedly connected to one end of a second worm shaft (510), the transmission shaft (506) and the second worm shaft (510) are rotatably connected to one side of the fixing frame (501) through a second bearing frame (509), a second worm shaft (511) is arranged above the second worm shaft (511) and is meshed with the second worm shaft, the second worm shaft (511) is fixedly connected to one end of the first worm wheel (512), shielding plates (513) are fixedly arranged on the outer wall of the rotating drum (512), the worm wheels (512) are rotatably connected to the outer wall of the rotating drum (514) and are fixedly connected to the outer wall of the cross bar (514).

9. The intelligent imaging detection device for orbital diseases according to claim 8, wherein a linkage gear (504) on the same horizontal plane as the linkage toothed plate (410) is fixedly arranged at the top end of the worm shaft I (503), and the linkage gear (504) is meshed with the linkage toothed plate (410).