CN216623582U

CN216623582U - Mechanical transmission demonstration teaching aid

Info

Publication number: CN216623582U
Application number: CN202122460093.4U
Authority: CN
Inventors: 王辉; 黄国华
Original assignee: Zhoushan Navigation School
Current assignee: Zhoushan Navigation School
Priority date: 2021-10-12
Filing date: 2021-10-12
Publication date: 2022-05-27
Anticipated expiration: 2031-10-12

Abstract

The application discloses mechanical transmission demonstrates teaching aid, including casing, show stand and elevating gear, presentation device and transmission, elevating gear includes supporting leg, carousel, driving gear, connecting axle, intermediate gear, drive gear, movable rod, helicla flute, fixed cover, solid fixed ring, bracing piece and guide bar, and the inside of casing rotates respectively through the connecting axle and connects driving gear and intermediate gear, and the top of casing is provided with the show stand. This application is through rotating the carousel, the carousel drives the driving gear and passes through the connecting axle and rotate, the driving gear rotates and drives two intermediate gear rotations that the meshing is connected, two intermediate gear rotate with two drive gear, two drive gear drive two movable rods respectively and rotate, two movable rods drive fixed cover and rotate, fixed cover slides through helicla flute and guide bar, the guide bar shifts up and drives the bracing piece along the helicla flute and shifts up, the bracing piece shifts up with solid fixed ring sliding connection and drive the show stand, thereby the height of convenient adjustment show stand.

Description

Mechanical transmission demonstration teaching aid

Technical Field

The application relates to the technical field of mechanical teaching, in particular to a mechanical transmission demonstration teaching aid.

Background

The mechanical industry is the traditional industry of China, at present, a large number of mechanical professions are developed in various professional technical schools and skilled schools all over the country, a mechanical basic course is an important component in the course learning of the mechanical profession, the main teaching content refers to the transmission of power and movement by using a mechanical mode, and teachers often use mechanical mechanism teaching aids to perform actual demonstration in order to enable students to know the characteristics, working principles and structures of common mechanical transmission mechanisms more intuitively in the teaching process.

Traditional mechanical mechanism teaching aid function singleness, bulky, it is very inconvenient to use, does not have the demonstration of practical application example moreover, and teaching effect is general in the teaching, and the inconvenient adjustment of general demonstration teaching aid demonstrates the height to influence the student and use and operate. Therefore, a mechanical transmission demonstration teaching aid is provided for the problems.

Disclosure of Invention

The mechanical transmission demonstration teaching aid provided in this embodiment is used for solving traditional mechanical mechanism teaching aid function singleness, bulky, uses very inconveniently, does not have practical application example demonstration moreover, and teaching effect is general in the teaching, and the inconvenient adjustment of general demonstration teaching aid demonstrates the height to influence the problem that the student used and operated.

According to one aspect of the application, a mechanical transmission demonstration teaching aid is provided, which comprises a shell, a display stand, a lifting device, a demonstration device and a transmission device, wherein the shell is provided with a plurality of through holes;

the lifting device comprises a supporting leg, a turntable, a driving gear, a connecting shaft, an intermediate gear, a transmission gear, a movable rod, a spiral groove, a fixed sleeve, a fixed ring, a supporting rod and a guide rod, wherein the inside of the shell is respectively and rotatably connected with the driving gear and the intermediate gear through the connecting shaft, and the top of the shell is provided with a display stand;

the demonstration device comprises a dustproof cover, a demonstration seat, a screw rod, a first gear, a second gear, a crank, a movable nut, a rack plate and connecting seats, wherein the dustproof cover is hinged to the top end of the demonstration platform, the demonstration seat is installed at the top of the demonstration platform, and the side wall of one end of the demonstration seat is fixedly connected with the two connecting seats;

the transmission device comprises a guide groove, a guide plate, half gears, a transmission rod, a disc, a guide rail and a slide rod, the top of the display seat is rotatably connected with the two half gears through a rotating shaft, and one end of each half gear is fixedly connected with one end of the transmission rod.

Furthermore, the bottom end of the shell is fixedly connected with four supporting legs, and the four supporting legs are symmetrically distributed around the bottom end of the shell.

Furthermore, a connecting shaft at one end of the driving gear penetrates through the side wall of the shell and is fixedly connected with the turntable, the driving gear is meshed with two intermediate gears, and the intermediate gears are meshed with the transmission gear.

Furthermore, the inside of the shell is rotatably connected with a movable rod, one end of the movable rod is sleeved with a transmission gear, and the outer side of the movable rod is fixedly connected with a fixed sleeve.

Further, the spiral groove that the spiral distributes is seted up to the inside of fixed cover, the inside sliding connection guide bar of spiral groove, the one end fixed connection bracing piece's of guide bar one end, the one end sliding connection of bracing piece is in the fixed ring, fixed ring fixed connection is inside the top of casing.

Further, the quantity of bracing piece is two, two the bottom lateral wall of solid fixed ring and fixed connection show stand is all run through to the top of bracing piece.

Furthermore, a screw rod is rotatably connected between the two connecting seats, the screw rod is in threaded connection with a movable nut, and the movable nut is fixedly connected to one end of each of the two rack plates.

Further, the inside guide way of having seted up of one end of rack plate, the inside sliding connection deflector of guide way, deflector fixed connection is at the one end lateral wall of show seat, the rack plate meshing connects the semi-gear, the quantity of semi-gear is two, two semi-gear symmetric distribution is in one side of two rack plates.

Furthermore, two guide rails are arranged on one side of the top of the display seat, a slide bar is slidably connected inside the guide rails, a disc is fixedly connected to the outer side of one end of the slide bar, and one end of the disc is fixedly connected with one end of the transmission rod.

Furthermore, one end of the screw rod is fixedly connected with a first gear, the first gear is meshed with a second gear, the second gear is rotatably connected to one end side wall of the display seat through a rotating shaft, and one end of the second gear is fixedly connected with a crank.

Through the above-mentioned embodiment of this application, adopted elevating gear, presentation device and transmission, solved traditional mechanical mechanism teaching aid function singleness, bulky, it is very inconvenient to use, does not have practical application example demonstration moreover, and teaching effect is general in the teaching, and the inconvenient adjustment of general demonstration teaching aid demonstrates the height to influence the problem that the student used and operated.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the description below are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without inventive labor.

FIG. 1 is a schematic overall perspective view of an embodiment of the present application;

FIG. 2 is a schematic overall structure of an embodiment of the present application;

fig. 3 is a schematic view of an internal structure of a display stand according to an embodiment of the present application.

In the figure: 1. a housing; 2. supporting legs; 3. a turntable; 4. a driving gear; 5. a connecting shaft; 6. an intermediate gear; 7. a transmission gear; 8. a movable rod; 9. a helical groove; 10. fixing a sleeve; 11. a fixing ring; 12. a support bar; 13. a guide bar; 14. a dust cover; 15. a display seat; 16. a display stand; 17. a screw rod; 18. a first gear; 19. a second gear; 20. a crank; 21. a movable nut; 22. a rack plate; 23. a guide groove; 24. a guide plate; 25. a half gear; 26. a transmission rod; 27. a disc; 28. a guide rail; 29. a slide bar; 30. a connecting seat.

Detailed Description

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all 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 application.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be used. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In this application, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings. These terms are used primarily to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to a particular orientation or to be constructed and operated in a particular orientation.

Moreover, some of the above terms may be used to indicate other meanings besides the orientation or positional relationship, for example, the term "on" may also be used to indicate some kind of attachment or connection relationship in some cases. The specific meaning of these terms in this application will be understood by those of ordinary skill in the art as appropriate.

Furthermore, the terms "mounted," "disposed," "provided," "connected," and "sleeved" are to be construed broadly. For example, it may be a fixed connection, a removable connection, or a unitary construction; can be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements or components. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

The demonstration teaching aid in this embodiment can be applicable to various mechanical teaching and use, for example, provides following demonstration teaching aid in this embodiment, and demonstration teaching aid in this embodiment can be used to carry out following presentation device and improve.

A transmission system demonstration device for middle-position machinery teaching comprises a placing shell, a first glass window, a second glass window, a dustproof mechanism, a fixing mechanism and a gear belt transmission mechanism; the side surface of the top of the placing shell is fixedly connected with the first glass window, and the side surface of the front of the placing shell is fixedly connected with the second glass window;

the dustproof mechanism comprises a fixed plate, a connecting plate and dustproof cloth, the fixed plate is fixedly connected to the top side surface of the placing shell, the connecting plate is fixedly connected to one side surface of the fixed plate, the dustproof cloth attached to the top side surface of the placing shell is fixedly connected to one side surface of the connecting plate, and under the action of the arranged dustproof mechanism, the surfaces of the first glass window and the second glass window can be conveniently protected, the cleanness of the surfaces of the first glass window and the second glass window can be conveniently improved, and the operation of workers is convenient;

the fixing mechanism comprises a fixing block, a clamping block, a mounting seat, a fixing bolt and a clamping groove, one side surface of the fixing block is fixedly connected with one side surface of the placing shell, the back side surface of the fixing block is fixedly connected with the front side surface of the clamping block, the back side surface of the fixing block is attached to the front side surface of the mounting seat, the clamping groove is formed in the front side surface of the mounting seat, the clamping block is clamped and connected with the inner cavity of the clamping groove, and the fixing bolt is connected to the side surface of the mounting seat in a threaded manner, so that the placing shell can be conveniently fixed to the surface of the mounting seat through the fixing block, the placing stability of the placing shell is improved, workers can conveniently fix the placing shell, and the using requirements of the workers are met;

the gear belt transmission mechanism comprises a servo motor, a pinion, a gear wheel, a driving shaft, a first rotating wheel, a belt, a second rotating wheel and a driven shaft, wherein the servo motor is fixedly connected with the inner wall of the back side of the placing shell, the pinion is fixedly sleeved on the surface of an output shaft of the servo motor, the right side of the pinion is meshed with the gear wheel, the driving shaft is sleeved in a gear wheel inner cavity, one end of the driving shaft is rotatably connected with the inner wall of the placing shell, the other end of the driving shaft is rotatably connected with the first rotating wheel, the surface of the first rotating wheel is rotatably sleeved with the belt through rotation, the second rotating wheel is rotatably connected with the second rotating wheel, the driven shaft is fixedly sleeved in the inner cavity of the second rotating wheel, the back side end of the driven shaft is rotatably connected with the inner wall of the placing shell, a worker can conveniently demonstrate gear rotation and belt rotation for students, and can better understand students, has good market value.

Two handles are fixedly connected to the surfaces of two opposite sides of the placing shell, and the handles are symmetrically distributed around the placing shell, so that the compact placing of the handles is guaranteed, and the placing shell is convenient to carry; the LED panel lamps are fixedly connected to the inner wall of the placing shell, the number of the LED panel lamps is two, and the two LED panel lamps are located on the two opposite side surfaces of the inner cavity wall of the placing shell, so that the LED panel lamps can supplement light to the inner cavity of the placing shell conveniently, and the LED panel lamps are convenient to watch; the side surface of the mounting seat is in threaded connection with two fixing bolts, and the tail ends of the fixing bolts penetrate through the side surface of the mounting seat to be tightly attached to the surface of the fixture block, so that the fixture block can be conveniently fixed through the fixing bolts; the number of the fixed blocks is two, and the two fixed blocks are symmetrically distributed relative to the placing shell, so that the fixed blocks are ensured to be placed compactly; the number of the fixing plates is two, and the two fixing plates are fixedly connected through a connecting plate, so that the two fixing plates can be conveniently placed; the number of the installation seats is two, and the back side surfaces of the two installation seats and the back side surface of the placing shell are on the same horizontal plane, so that the installation seats can be conveniently used; the driving shaft and the driven shaft are arranged in parallel, so that the driving shaft and the driven shaft are ensured to be arranged reasonably and compactly; the right side surface of the mounting seat is in threaded connection with two mounting bolts, and the tail ends of the mounting bolts penetrate through the surface of the mounting seat, so that the mounting seat can be conveniently fixed through mounting; the cross section of the handle is of a U-shaped structure, and the handle and the fixing block are vertically distributed, so that the use is convenient.

Of course, the present embodiment can also be used for other machine teaching. The description is omitted, and the demonstration teaching aid of the embodiment of the application is introduced below.

Referring to fig. 1-3, a mechanical transmission demonstration teaching aid comprises a shell 1, a display stand 16, a lifting device, a demonstration device and a transmission device;

the lifting device comprises supporting legs 2, a rotary table 3, a driving gear 4, a connecting shaft 5, an intermediate gear 6, a transmission gear 7, a movable rod 8, a spiral groove 9, a fixed sleeve 10, a fixed ring 11, a supporting rod 12 and a guide rod 13, wherein the inside of the shell 1 is respectively and rotatably connected with the driving gear 4 and the intermediate gear 6 through the connecting shaft 5, and the top of the shell 1 is provided with a display platform 16;

the demonstration device comprises a dustproof cover 14, a display seat 15, a screw rod 17, a first gear 18, a second gear 19, a crank 20, a movable nut 21, a rack plate 22 and connecting seats 30, wherein the dustproof cover 14 is hinged to the top end of the display stand 16, the display seat 15 is installed at the top of the display stand 16, and the side wall of one end of the display seat 15 is fixedly connected with the two connecting seats 30;

the transmission device comprises a guide groove 23, a guide plate 24, a half gear 25, a transmission rod 26, a disc 27, a guide rail 28 and a sliding rod 29, the top of the display seat 15 is rotatably connected with the two half gears 25 through a rotating shaft, and one end of each half gear 25 is fixedly connected with one end of the transmission rod 26.

Through rotating the carousel, the carousel drives the driving gear and passes through the connecting axle and rotate, the driving gear rotates and drives two intermediate gear rotations that the meshing is connected, two intermediate gear rotate with two drive gear, two drive gear drive two movable rod rotations respectively, two movable rod drive fixed cover and rotate, fixed cover slides through helicla flute and guide bar, the guide bar shifts up and drives the bracing piece along the helicla flute and shifts up, the bracing piece shifts up with solid fixed ring sliding connection and drive the show stand to the height of convenient adjustment show stand.

The bottom end of the shell 1 is fixedly connected with four supporting legs 2, and the four supporting legs 2 are symmetrically distributed around the bottom end of the shell 1; a connecting shaft 5 at one end of the driving gear 4 penetrates through the side wall of the shell 1 and is fixedly connected with the turntable 3, the driving gear 4 is meshed with two intermediate gears 6, and the intermediate gears 6 are meshed with a transmission gear 7; the inner part of the shell 1 is rotatably connected with a movable rod 8, one end of the movable rod 8 is sleeved with a transmission gear 7, and the outer side of the movable rod 8 is fixedly connected with a fixed sleeve 10; the spiral groove 9 which is spirally distributed is formed in the fixed sleeve 10, the inside of the spiral groove 9 is connected with the guide rod 13 in a sliding manner, one end of the guide rod 13 is fixedly connected with one end of the supporting rod 12, one end of the supporting rod 12 is connected in the fixed ring 11 in a sliding manner, and the fixed ring 11 is fixedly connected with the inside of the top end of the shell 1; the number of the supporting rods 12 is two, and the top ends of the two supporting rods 12 penetrate through the fixing ring 11 and are fixedly connected with the side wall of the bottom end of the display stand 16; a screw rod 17 is rotatably connected between the two connecting seats 30, the screw rod 17 is in threaded connection with a movable nut 21, and the movable nut 21 is fixedly connected to one end of each of the two rack plates 22; a guide groove 23 is formed in one end of each rack plate 22, the guide groove 23 is connected with a guide plate 24 in a sliding mode, the guide plate 24 is fixedly connected to one end side wall of the display seat 15, the rack plates 22 are meshed with half gears 25, the number of the half gears 25 is two, and the two half gears 25 are symmetrically distributed on one side of each rack plate 22; two guide rails 28 are arranged on one side of the top of the display base 15, a slide bar 29 is slidably connected inside the guide rails 28, a disc 27 is fixedly connected to the outer side of one end of the slide bar 29, and one end of the disc 27 is fixedly connected to one end of a transmission rod 26; one end of the screw rod 17 is fixedly connected with a first gear 18, the first gear 18 is meshed with a second gear 19, the second gear 19 is rotatably connected to one end side wall of the display base 15 through a rotating shaft, and one end of the second gear 19 is fixedly connected with a crank 20.

When the device is used, firstly, all electrical components in the device are externally connected with a control switch and a power supply, then the turntable 3 is rotated, the turntable 3 drives the driving gear 4 to rotate through the connecting shaft 5, the driving gear 4 rotates and drives the two intermediate gears 6 which are connected in a meshed manner to rotate, the two intermediate gears 6 and the two transmission gears 7 rotate, the two transmission gears 7 respectively drive the two movable rods 8 to rotate, the two movable rods 8 drive the fixed sleeve 10 to rotate, the fixed sleeve 10 slides through the spiral groove 9 and the guide rod 13, the guide rod 13 moves upwards along the spiral groove 9 and drives the support rod 12 to move upwards, the support rod 12 is in sliding connection with the fixed ring 11 and drives the display platform 16 to move upwards, so that the height of the display platform 16 is conveniently adjusted, the hinged dustproof cover 14 is opened, the crank 20 is rotated to drive the second gear 19 to rotate, and the second gear 19 drives the first gear 18 which is connected in a meshed manner to rotate, the first gear 18 drives the screw rod 17 to rotate, the screw rod 17 and the movable nut 21 rotate in a threaded mode, the movable nut 21 moves along the screw rod 17, the movable nut 21 drives the rack plates 22 to slide along the guide plates 24 through the guide grooves 23, the two rack plates 22 move and drive the half gears 25 connected in a meshed mode to rotate, the half gears 25 drive the transmission rod 26 to rotate, the transmission rod 26 drives the disc 27 to slide along the guide rails 28 through the sliding rods 29, and mechanical transmission is conveniently demonstrated through the rack plates 22, the half gears 25, the screw rod 17, the movable nut 21, the first gear 18 and the second gear 19, and the demonstration and the use are convenient.

The application has the advantages that:

1. the rotary table is simple to operate, the rotary table drives the driving gear to rotate through the connecting shaft by rotating the rotary table, the driving gear rotates and drives the two intermediate gears which are connected in a meshed mode to rotate, the two intermediate gears and the two transmission gears rotate, the two transmission gears respectively drive the two movable rods to rotate, the two movable rods drive the fixed sleeve to rotate, the fixed sleeve slides through the spiral groove and the guide rod, the guide rod moves upwards along the spiral groove and drives the support rod to move upwards, and the support rod is connected with the fixed ring in a sliding mode and drives the display platform to move upwards, so that the height of the display platform can be adjusted conveniently;

2. the structure is reasonable, the crank is rotated to drive the second gear to rotate, the second gear drives the first gear which is in meshed connection to rotate, the first gear drives the screw rod to rotate, the screw rod and the movable nut rotate in a threaded mode, the movable nut moves along the screw rod, the movable nut drives the rack plates to slide along the guide plate through the guide groove, the two rack plates move and drive the half gears which are in meshed connection to rotate, the half gears drive the transmission rod to rotate, the transmission rod drives the disc to slide along the guide rail through the slide rod, and mechanical transmission is conveniently displayed;

3. this application is rational in infrastructure, demonstrates convenient show and use to mechanical transmission through rack plate, semi-gear, lead screw, movable nut, first gear and second gear.

The present application relates to circuits and electronic components and modules, all of which are well within the skill of those in the art and, needless to say, does not relate to software or process improvements.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. The utility model provides a mechanical transmission demonstrates teaching aid which characterized in that: comprises a shell (1), a display stand (16), a lifting device, a demonstration device and a transmission device;

the lifting device comprises supporting legs (2), a rotary table (3), a driving gear (4), a connecting shaft (5), an intermediate gear (6), a transmission gear (7), a movable rod (8), a spiral groove (9), a fixed sleeve (10), a fixed ring (11), a supporting rod (12) and a guide rod (13), the inside of the shell (1) is respectively and rotatably connected with the driving gear (4) and the intermediate gear (6) through the connecting shaft (5), and a display stand (16) is arranged at the top of the shell (1);

the demonstration device comprises a dustproof cover (14), a demonstration seat (15), a screw rod (17), a first gear (18), a second gear (19), a crank (20), a movable nut (21), a rack plate (22) and connecting seats (30), wherein the dustproof cover (14) is hinged to the top end of the demonstration platform (16), the demonstration seat (15) is installed at the top of the demonstration platform (16), and the side wall of one end of the demonstration seat (15) is fixedly connected with the two connecting seats (30);

the transmission device comprises a guide groove (23), a guide plate (24), half gears (25), a transmission rod (26), a disc (27), a guide rail (28) and a sliding rod (29), the top of the display seat (15) is rotatably connected with the two half gears (25) through a rotating shaft, and one end of each half gear (25) is fixedly connected with one end of the transmission rod (26).

2. A mechanical transmission demonstration teaching aid according to claim 1, wherein: the bottom fixed connection supporting leg (2) of casing (1), the quantity of supporting leg (2) is four, four supporting leg (2) symmetric distribution is around the bottom of casing (1).

3. A mechanical transmission demonstration teaching aid according to claim 1, wherein: connecting axle (5) of driving gear (4) one end runs through the lateral wall of casing (1) and fixed connection carousel (3), two intermediate gear (6) are connected in the meshing of driving gear (4), transmission gear (7) are connected in the meshing of intermediate gear (6).

4. A mechanical transmission demonstration teaching aid according to claim 1, wherein: the inside of casing (1) is rotated and is connected movable rod (8), drive gear (7) have been cup jointed to the one end of movable rod (8), the fixed cover (10) of outside fixed connection of movable rod (8).

5. A mechanical transmission demonstration teaching aid according to claim 1, wherein: the spiral groove (9) that the spiral distributes are seted up to the inside of fixed cover (10), the inside sliding connection guide bar (13) of spiral groove (9), the one end of the one end fixed connection bracing piece (12) of guide bar (13), the one end sliding connection of bracing piece (12) is in solid fixed ring (11), gu fixed ring (11) fixed connection is inside the top of casing (1).

6. A mechanical transmission demonstration teaching aid according to claim 1, wherein:

the number of the supporting rods (12) is two, and the top ends of the supporting rods (12) penetrate through the fixing rings (11) and are fixedly connected with the side wall of the bottom end of the display stand (16).

7. A mechanical transmission demonstration teaching aid according to claim 1, wherein: two rotate between connecting seat (30) and connect lead screw (17), lead screw (17) threaded connection movable nut (21), movable nut (21) fixed connection is in the one end of two rack plates (22).

8. A mechanical transmission demonstration teaching aid according to claim 1, wherein: guide way (23) have been seted up to the one end inside of rack plate (22), inside sliding connection deflector (24) of guide way (23), deflector (24) fixed connection is at the one end lateral wall of show seat (15), half gear (25) are connected in rack plate (22) meshing, the quantity of half gear (25) is two, two half gear (25) symmetric distribution is in one side of two rack plates (22).

9. A mechanical transmission demonstration teaching aid according to claim 1, wherein: two guide rails (28) have been seted up to top one side of show seat (15), the inside sliding connection slide bar (29) of guide rail (28), the one end outside fixed connection disc (27) of slide bar (29), the one end fixed connection transfer line (26) of disc (27) one end.

10. A mechanical transmission demonstration teaching aid according to claim 1, wherein: one end fixed connection first gear (18) of lead screw (17), first gear (18) meshing connection second gear (19), second gear (19) rotate through the pivot and connect in the one end lateral wall of show seat (15), the one end fixed connection crank (20) of second gear (19).