CN115531342A

CN115531342A - Preparation method of tenofovir disoproxil fumarate tablets and storage and transportation device

Info

Publication number: CN115531342A
Application number: CN202211427713.7A
Authority: CN
Inventors: 章坛; 庞京团; 曾依铃; 莫淑羽
Original assignee: Zhongyu Pharmaceutical Haikou Co ltd
Current assignee: Zhongyu Pharmaceutical Haikou Co ltd
Priority date: 2022-11-15
Filing date: 2022-11-15
Publication date: 2022-12-30

Abstract

The invention discloses a preparation method of tenofovir disoproxil fumarate tablets and a storage and transportation device, which comprise the following steps: step S01, raw and auxiliary materials are used, materials are taken, the temperature of a temporary storage room of the raw and auxiliary materials is kept at 18 to 26 ℃, and the humidity is kept at 45 to 65%; and S02, crushing and sieving, wherein the tenofovir disoproxil fumarate in the step S01 is sieved by a 80-mesh sieve, the cover plate and the placing plate are arranged to achieve the effect of damping the medicine bottles when the medicine bottles are transported through a bumpy road section, and the cover plate can ascend when the placing frame is pulled through the linkage of the telescopic mechanism, so that the placing frame is more conveniently pulled to slide out of the box body, the medicine boxes are conveniently placed, the cover plate can be pressed down after the placing frame is retracted into the box body to extrude the medicine boxes, the situation that the medicine boxes slide out of the placing holes is avoided, and the stability of the medicine bottles in the transportation process is further improved.

Description

Preparation method of tenofovir disoproxil fumarate tablets and storage and transportation device

Technical Field

The invention relates to the technical field of storage and transportation devices, in particular to a preparation method of tenofovir disoproxil fumarate tablets and a storage and transportation device.

Background

At present need put into the warehouse at the in-process of transporting tenofovir disoproxil fumarate piece, but the warehouse has certain distance apart from the workshop, just so need adopt fork truck's mode with the medicine transport to the warehouse in, but in the in-process of carrying out the transportation, some road surfaces can be because of maintenance or the condition mode that appears pothole long for the time of the maintenance, like this in the in-process fork truck of transportation can lead to the condition that the medicine bottle appears damaging because of jolting on road surface, and medicine can expose in the air after the medicine bottle is broken, the condition mode that degenerates appears easily in the medicine like this, caused economic loss to the enterprise, so the urgent need for a storage conveyer that the protecting effect is good.

Disclosure of Invention

The invention aims to provide a preparation method and a storage and transportation device of tenofovir disoproxil fumarate tablets, so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

a preparation method of tenofovir disoproxil fumarate tablets comprises the following steps:

s01, using raw and auxiliary materials, taking materials, keeping the temperature of the temporary storage room of the raw and auxiliary materials at 18-26 ℃, and keeping the humidity at 45-65%;

s02, crushing and sieving, wherein the tenofovir disoproxil fumarate in the step S01 is sieved by a 80-mesh sieve, and the microcrystalline cellulose, the pregelatinized starch, the lactose, the croscarmellose sodium and the magnesium stearate are respectively sieved by a 60-mesh sieve, and then weighing for later use;

step S03, mixing, namely putting tenofovir disoproxil fumarate, microcrystalline cellulose, lactose and croscarmellose sodium into a wet mixing granulator, and starting a stirring device to mix for 10 to 30min;

s04, preparing a soft material adhesive, adding a prescribed amount of pregelatinized starch into a prescribed amount of purified water, heating to 80 ℃ while stirring, stopping heating, and cooling to 30-70 ℃ to obtain the adhesive;

s05, granulating, namely transferring the prepared soft material into a swing type granulator, and screening the soft material through a 20-mesh sieve to prepare wet granules;

step S06, drying, namely drying the wet granules in a boiling dryer at the air inlet temperature of 60 +/-10 ℃, discharging when the moisture of the granules is dried to 1.0-4.0%, and obtaining dry granules;

s07, finishing, namely taking out the dried particles, and screening the particles through a stainless steel screen mesh of 20 meshes to finish the particles;

and S08, totally mixing, sampling, measuring the content of the granules, transferring the granulated dry granules to a multidirectional motion mixer, adding the magnesium stearate with the prescription amount, and starting the machine for mixing for 10min. Sampling, measuring the raw material content in the particles, and calculating the theoretical weight of the tablets;

and step S09, tabletting, installing a die on the tabletting machine, adjusting proper filling amount and pressure according to the calculated theoretical weight of the tablet, and starting up the machine for pressure test. The speed is less than 50HZ, the pressure is more than 50N, after the debugging is qualified, the machine is started to continuously carry out tabletting, and the filling amount is properly adjusted according to the change of the tablet weight, so that the tablet weight is maintained in the deviation range of +/-5 percent;

step S10, coating, namely weighing a proper amount of Opadry film coating powder, adding the Opadry film coating powder into a proper amount of purified water while stirring, fully stirring and swelling, opening a coating pot, setting the hot air temperature to be 75 ℃, the exhaust air temperature to be 55 ℃, the core temperature to be 45 ℃, and the rotating speed of the pot body to be 3 to 15 rpm. Pouring the plain tablets into a pot body, and preheating for 30min. During coating, the fluidization state and the temperature of the tablet bed in the pan body are observed at any time, and the liquid spraying speed is properly adjusted to prevent the tablets from being adhered due to over-wet. After the coating liquid is sprayed, the spray gun is closed, the pot body continues to rotate and dry, the water content of the coated tablet is controlled to be 1 to 4 percent, and the machine is stopped;

step S11, bottling, adjusting by a tablet counting machine, filling the film-coated tablets into high-density polyethylene bottles, adding 1 bag of drying agent into each bottle with 30 tablets in each bottle, and sealing;

step S12, labeling, namely labeling the printed label to a high-density polyethylene bottle filled with the medicine;

s13, boxing, sending the specification and 1 bottle of the medicine into a small box, and spraying a word pattern of 'product batch number, production date and effective period' on the small box;

and S14, packaging, namely boxing the boxed medicines, and putting the boxed medicines into a storage and transportation device for transportation.

The application also provides a tenofovir disoproxil fumarate storage and transportation device, and the preparation method of the tenofovir disoproxil fumarate is applied, the storage and transportation device comprises a movable base, a box body is connected above the base, a partition plate is connected at the inner wall of the box body, placing frames are respectively in sliding fit at the bottom of the inner wall of the box body and above the partition plate, a plurality of placing holes are formed above the placing frames, a placing plate is elastically matched in the vertical direction of the placing holes, and a foldable push rod is connected above the base;

bottom half top and baffle top all are connected with telescopic machanism, and telescopic machanism's top is connected with the apron that is located the rack top, and one side of rack is rotated and is connected with the arc push pedal.

Preferably, telescopic machanism is including the connecting rod that is located bottom half top and baffle top, offers the cross section for the straight flute of T shape on the vertical direction of connecting rod, sliding fit have and the apron between the slide bar of being connected on the vertical direction of straight flute, the lower extreme of slide bar is connected with the disc of sliding fit on the straight flute parallel direction, the constant head tank has been seted up to one side of barrel, be connected with the first spring that the cover was established in slide bar week side between the top of disc and the straight flute inner wall top.

Preferably, the straight flute includes rectangular channel and columnar order groove, and the constant head tank has been seted up to one side of rectangular channel, and elastic fit has the kelly on the parallel direction of constant head tank, and the draw-in groove with kelly looks adaptation is seted up to one side of slide bar, and the one end of kelly is connected with L shape pole, and one side of L shape pole is connected with the push rod, and the push rod is located one side of rack.

Preferably, one side of the box body is provided with a groove, one side of the arc-shaped push plate is connected with a rod body rotatably connected in the parallel direction of the groove, one end of the rod body is connected with a first worm wheel, the upper part of the groove is provided with a rotating groove, and the parallel direction of the rotating groove is rotatably connected with a first worm meshed with the first worm wheel.

Compared with the prior art, the invention has the beneficial effects that:

according to the medicine box placing device, the cover plate and the placing plate are arranged, so that the medicine box can be damped when a medicine bottle is transported through a bumpy road section, the cover plate can be lifted when the placing frame is pulled through the linkage of the telescopic mechanism, the placing frame can be pulled to be more convenient when the placing frame slides out of the box body, the medicine box can be placed conveniently, the cover plate can be pressed down after the placing frame is retracted into the box body, the medicine box is extruded, the medicine box is prevented from sliding out of the placing hole, the stability of the medicine bottle in the transportation process is further improved, the handle is foldable, the occupied space of the transportation device is reduced, and the transportation device can be conveniently stored by personnel.

Drawings

FIG. 1 is a schematic view of a preparation process of the present invention;

FIG. 2 is a schematic overall view of the storage and transportation apparatus of the present invention;

FIG. 3 is a schematic perspective view of the interior of the storage and transportation device of the present invention;

FIG. 4 is a schematic top sectional view of the rack of the present invention;

FIG. 5 is a schematic sectional view of the mounting plate and first worm combination of the present invention;

FIG. 6 is a schematic view of the structure of FIG. 2 at A in accordance with the present invention;

FIG. 7 is a schematic view of the structure of FIG. 3 at B in accordance with the present invention;

FIG. 8 is a schematic view of the structure of FIG. 3 at C according to the present invention.

In the figure: 1. a base; 2. a box body; 3. a partition plate; 4. placing a rack; 5. placing holes; 6. placing a plate; 7. a handle; 8. a cover plate; 9. an arc-shaped push plate; 10. a connecting rod; 11. a straight groove; 12. a slide bar; 13. a disc; 14. a first spring; 15. positioning a groove; 16. a clamping rod; 17. an L-shaped rod; 18. a push rod; 19. a groove; 20. a rod body; 21. a first worm gear; 22. a rotating groove; 23. a first worm; 24. a gear; 25. rotating the rod; 26. a face gear; 27. a straight rod; 28. fixing the rod; 29. a U-shaped frame; 30. a connecting disc; 31. positioning a rod; 32. a second worm gear; 33. mounting a plate; 34. a second worm; 35. a ring body.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 to 8, a method for preparing tenofovir disoproxil fumarate tablets comprises the following steps:

s05, granulating, namely transferring the prepared soft material into a swing granulator, and screening the soft material through a 20-mesh sieve to prepare wet granules;

step S06, drying, namely drying the wet granules in a boiling dryer at the air inlet temperature of 70 +/-5 ℃, discharging the granules when the water content of the granules is dried to 1.0 to 3.0 percent, and obtaining dry granules;

and step S08, totally mixing, sampling, measuring the content of the granules, transferring the granulated dry granules to a multi-directional motion mixer, adding the magnesium stearate with the prescription amount, and starting the machine for mixing for 10min. Sampling, measuring the content of the raw materials in the particles, and calculating the theoretical weight of the tablets;

and step S09, tabletting, installing a die on the tabletting machine, adjusting proper filling amount and pressure according to the calculated theoretical weight of the tablet, and starting up the machine for pressure test. After the debugging is qualified, starting the machine for continuous tabletting, and properly adjusting the filling amount according to the change of the tablet weight to keep the tablet weight within the deviation range of +/-5 percent;

step S10, coating, namely weighing a proper amount of Opadry film coating powder, adding the Opadry film coating powder into a proper amount of purified water with the solid content of 12% while stirring, fully stirring and swelling, opening a coating pot, setting the hot air temperature to be 75 ℃, the exhaust temperature to be 55 ℃, the core temperature to be 40 to 60 ℃, and the rotating speed of the pot body to be 3 to 20 rpm. Pouring the plain tablets into a pot body, and preheating for 30min. During coating, the fluidization state and the temperature of the tablet bed in the pan body are observed at any time, and the liquid spraying speed is properly adjusted to prevent the tablets from being adhered due to over-wet. After the coating liquid is sprayed, the spray gun is closed, the pot body continues to rotate and dry, the water content of the coated tablet is controlled to be 1 to 3 percent, and the machine is stopped;

s13, boxing, sending the specification and 1 bottle of the medicine into a small box, and spraying a character pattern from the product batch number, the production date and the validity period to the small box;

and S14, packaging, namely, boxing the boxed medicines, and putting the boxes filled with the medicines into a storage and transportation device for transportation.

The application also provides a tenofovir disoproxil fumarate storage and transportation device, the preparation method of the tenofovir disoproxil fumarate is applied, the storage and transportation device comprises a movable base 1, a box body 2 is connected above the base 1, a partition plate 3 is connected to the inner wall of the box body 2, the box body 2 can be divided into two spaces by the partition plate 3, a placing frame 4 is arranged on the bottom of the inner wall of the box body 2 and the top of the partition plate 3 in a sliding fit manner, a dovetail groove for sliding the dovetail block is arranged above the partition plate 4 and above the bottom of the inner wall of the box body 2, a plurality of placing holes 5 are arranged above the placing frame 4, medicine boxes can be placed in the placing holes 5, a placing plate 6 is elastically matched in the vertical direction of the placing holes 5, the placing plate 6 can move up and down when the transportation device moves to a road section, the situation that the placing plate 6 is broken due to overlarge impact force is avoided, a handle 7 is connected above the base 1, a second spring is arranged between the placing hole 5 and the placing plate 6, and the handle 7 is convenient for a worker to move the transportation device, and four universal wheels below the base 1 are connected with the transportation device;

2 bottom tops of box and 3 tops of baffle all are connected with telescopic machanism, and telescopic machanism's top is connected with the apron 8 that is located the rack 4 top, and the below of apron 8 is connected with the rubber pad, and the setting of rubber pad can alleviate the impact force when medicine box collides apron 8, and one side of rack 4 is rotated and is connected with arc push pedal 9, and the setting of arc push pedal 9 upwards promotes apron 8, makes the below of apron 8 keep away from the medicine box, has made things convenient for follow-up pulling to rack 4.

The telescopic mechanism comprises a connecting rod 10 positioned above the bottom of a box body 2 and above a partition plate 3, the connecting rod 10 is connected with the partition plate 3 and the box body 2 in a welding mode, a straight groove 11 with a T-shaped cross section is formed in the vertical direction of the connecting rod 10, a sliding rod 12 connected with a cover plate 8 is arranged in the vertical direction of the straight groove 11 in a sliding fit mode, the sliding rod 12 is of a rectangular rod structure, the lower end of the sliding rod 12 is connected with a disc 13 in the parallel direction of the straight groove 11 in a sliding fit mode, the disc 13 is connected with the sliding rod 12 in a welding mode, a first spring 14 sleeved on the peripheral side of the sliding rod 12 is connected between the upper side of the disc 13 and the top of the inner wall of the straight groove 11, the sliding rod 12 is convenient for people to slide by the arrangement of the first spring 14, the sliding of the sliding rod 12 from the straight groove 11 is avoided by the arrangement of the disc 13, and the medicine box can be always pressed by the cover plate 8 by the arrangement of the first spring 14.

Straight flute 11 includes rectangular channel and columnar order groove, constant head tank 15 has been seted up to one side of rectangular channel, elastic fit has kelly 16 on the parallel direction of constant head tank 15, the draw-in groove of kelly 16 looks adaptation has been seted up to one side of slide bar 12, the one end of kelly 16 is connected with L shape pole 17, one side of L shape pole 17 is connected with push rod 18, push rod 18 is located one side of rack 4, the setting of rectangular channel has been avoided slide bar 12 to appear unsettled condition and has taken place, and the below of kelly 16 is connected with the arch, the below of constant head tank 15 has been seted up and has been supplied bellied notch, be connected with the third spring between notch and the arch.

Recess 19 has been seted up to one side of box 2, one side of arc push pedal 9 is connected with rotates the body of rod 20 of connection on recess 19 parallel direction, the one end of the body of rod 20 is connected with first worm wheel 21, rotation groove 22 has been seted up to recess 19's top, rotate in rotation groove 22's parallel direction be connected with first worm wheel 21 between the first worm 23 of meshing, self-locking nature through first worm wheel 21 and first worm 23 can improve the stability when arc push pedal 9 removes, the circumstances that the elasticity of having avoided apron 8 can make arc push pedal 9 remove takes place.

One end of the first worm 23 is connected with a gear 24, one side of the box body 2 is provided with a through hole, the parallel direction of the through hole is rotatably connected with a rotating rod 25, one end of the rotating rod 25 is connected with a gear 24 meshed with an end face gear 26, one end of the rotating rod 25 is connected with a knob, the knob is arranged to facilitate the rotation of a person on the rotating rod 25, and the end face gear 26 and the gear 24 are arranged to facilitate the rotation of the person on the rotating rod 25.

Spherical notch has been seted up to the one end of arc push pedal 9, and the inside activity of notch has the spheroid, and spheroidal setting has made things convenient for follow-up arc push pedal 9 contact apron 8 to when spurring rack 4, the spheroid has reduced the frictional force when laminating between arc push pedal 9 and the apron 8, and then has made things convenient for personnel to the removal of rack 4.

The handle 7 comprises a straight rod 27 and fixing rods 28, the upper end of the straight rod 27 is connected with a U-shaped frame 29, one end of each fixing rod 28 is connected with a connecting disc 30 rotatably connected in the U-shaped frame 29, the two sides of each connecting disc 30 are connected with a positioning rod 31, rotating holes for rotating the positioning rods 31 are formed in the two sides of the U-shaped frame 29, the push rod 18 is convenient for people to move the base 1, the U-shaped frame 29 is connected to the upper end of the straight rod 27 in a welding mode, the connecting discs 30 can be prevented from being suspended in the air due to the arrangement of the positioning rods 31, a limiting rod is connected between the two adjacent positioning rods 31, the two fixing rods 28 can be driven to rotate simultaneously due to the arrangement of the limiting rod, the fixing rods 28 can be moved conveniently, and the occupied space for storing and transporting devices can be reduced through the blocked push rods 18.

One end of one positioning rod 31 penetrates through a second worm wheel 32 connected with a rotating hole, one side of one U-shaped frame 29 is connected with a mounting plate 33, the opposite side of the mounting plate 33 penetrates through a notch, a second worm 34 meshed with the second worm wheel 32 is rotatably connected in the parallel direction of the notch, the self-locking property between the second worm 34 and the second worm wheel 32 improves the stability of the fixed rod 28 and the straight rod 27 after adjustment, and the mounting plate 33 is mounted on one side of the U-shaped frame 29 in a welding mode.

The week side of second worm 34 is connected with ring body 35, and the annular groove with ring body 35 looks adaptation is seted up to one side of notch inner wall, and the setting of annular groove and ring body 35 has avoided follow-up second worm 34 unsettled condition to appear to take place, has improved second worm 34 pivoted stability, and the one end of second worm 34 is connected with the carousel, and the carousel has made things convenient for personnel's second worm 34 rotation.

The working principle is as follows: when the medicine box needs to be stored, a door body on one side of the box body 2 is opened firstly, then the knob is rotated, a rotating rod 25 connected with the knob is enabled to rotate, an end face gear 26 connected with the rotating rod 25 is enabled to rotate, then the end face gear 26 can drive the worm to rotate through a gear 24, then the worm can drive a push plate to rotate through a worm gear, then the push plate can contact with the cover plate 8, and the cover plate 8 can move upwards, then a sliding rod 12 connected with the cover plate 8 can extrude a first spring 14 and move upwards, meanwhile, a third spring can generate elastic deformation and eject a clamping rod 16 into a clamping groove formed in the sliding rod 12, then the fixing of the position of the sliding rod 12 is completed, then a person pulls the placing frame 4, a dovetail block connected with an L-shaped rod 17 connected with the pushing rod 18 can slide out from the clamping groove, then the first spring 14 can generate elastic deformation, then the cover plate 8 can be pushed into the placing hole 5 again, then the placing frame 4 can slide into the box body 2, meanwhile, the pushing frame 4 can extrude the pushing rod 18, a clamping rod 16 connected with an L-shaped rod 17 connected with the pushing rod 18 can slide out from the clamping groove, then the rotating rod can rotate through a second rotating disc 34 and then the rotating disc 34 and rotate when the worm wheel 34 and the rotating disc can rotate, and then the rotating disc 34 and the rotating disc can rotate, and then rotate, and the second rotating disc 34.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments 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. A preparation method of tenofovir disoproxil fumarate tablets is characterized by comprising the following steps:

s02, crushing and sieving, namely sieving the tenofovir disoproxil fumarate obtained in the step S01 by a 80-mesh sieve, respectively sieving the microcrystalline cellulose, the pregelatinized starch, the lactose, the croscarmellose sodium and the magnesium stearate by a 60-mesh sieve, and then weighing for later use;

step S06, drying, namely drying the wet granules in a boiling dryer at the air inlet temperature of 60 +/-5 ℃, discharging the granules when the water content of the granules is dried to 1.0 to 4.0 percent, and obtaining dry granules;

step S08, total mixing, sampling, measuring the content of the granules, transferring the dried granules after finishing granules to a multidirectional motion mixer, adding magnesium stearate with the prescription amount, starting the machine for mixing for 10 to 30min, sampling, measuring the content of raw materials in the granules, and calculating the theoretical tablet weight;

s09, tabletting, namely installing a die on a tabletting machine, adjusting proper filling amount and pressure according to the calculated theoretical tablet weight, starting the machine for pressure test, starting the machine for continuous tabletting after the debugging is qualified, and properly adjusting the filling amount according to the variation of the tablet weight to keep the tablet weight within the deviation range of +/-5%;

step S10, coating, namely weighing a proper amount of Opadry film coating powder, adding the Opadry film coating powder into a proper amount of purified water while stirring, fully stirring and swelling, opening a coating pot, pouring plain tablets into the pot, preheating for 30 to 60min, observing the fluidization state of a tablet bed in the pot and the temperature of the tablet bed at any time in the coating process, properly adjusting the liquid spraying speed to prevent the tablets from being adhered due to over-wetting, closing a spray gun after coating liquid is sprayed, continuously rotating the pot for drying, controlling the water content of the coated tablets to be 1.0 to 4.0%, and stopping the machine;

2. A storage and transportation device for tenofovir disoproxil fumarate tablets is characterized in that the preparation method of the tenofovir disoproxil fumarate tablets is applied as claimed in claim 1, the storage and transportation device comprises a movable base (1), a box body (2) is connected above the base (1), a partition plate (3) is connected to the inner wall of the box body (2), a placing frame (4) is slidably matched at the bottom of the inner wall of the box body (2) and above the partition plate (3), a plurality of placing holes (5) are formed above the placing frame (4), a placing plate (6) is elastically matched in the vertical direction of the placing holes (5), and a foldable push rod (18) is connected above the base (1);

the upper part of the bottom of the box body (2) and the upper part of the clapboard (3) are both connected with a telescopic mechanism, the upper part of the telescopic mechanism is connected with a cover plate (8) positioned above the placing rack (4), and one side of the placing rack (4) is rotatably connected with an arc-shaped push plate (9).

3. The storage and transportation device of claim 2, wherein: telescopic machanism is including connecting rod (10) that are located box (2) bottom top and baffle (3) top, set up straight flute (11) that the cross section is T shape on the vertical direction of connecting rod (10), sliding fit has and laps slide bar (12) of being connected between (8) on the vertical direction of straight flute (11), the lower extreme of slide bar (12) is connected with sliding fit disc (13) on straight flute (11) parallel direction, constant head tank (15) have been seted up to one side of barrel, be connected with between the top of disc (13) and straight flute (11) inner wall top and establish first spring (14) that establish in slide bar (12) week side.

4. A storage and transportation arrangement as claimed in claim 3, wherein: straight flute (11) are including rectangular channel and columnar order groove, and constant head tank (15) have been seted up to one side of rectangular channel, and elastic fit has kelly (16) on the parallel direction of constant head tank (15), and the draw-in groove of kelly (16) looks adaptation is seted up to one side of slide bar (12), and the one end of kelly (16) is connected with L shape pole (17), and one side of L shape pole (17) is connected with push rod (18), and push rod (18) are located one side of rack (4).

5. The storage and transportation device of claim 4, wherein: recess (19) have been seted up to one side of box (2), and one side of arc push pedal (9) is connected with the body of rod (20) of rotation connection on recess (19) parallel direction, and the one end of the body of rod (20) is connected with first worm wheel (21), and rotation groove (22) have been seted up to the top of recess (19), rotate on the parallel direction of rotation groove (22) be connected with first worm (23) of meshing between first worm wheel (21).