CN113524971A

CN113524971A - Folding drawing board for art design

Info

Publication number: CN113524971A
Application number: CN202110792535.7A
Authority: CN
Inventors: 谷万里
Original assignee: Guilin University of Aerospace Technology
Current assignee: Guilin University of Aerospace Technology
Priority date: 2021-07-14
Filing date: 2021-07-14
Publication date: 2021-10-22

Abstract

The invention relates to the technical field of art design and discloses a folding drawing board for art design, which comprises two board bodies distributed on the left and right, wherein the two board bodies are rotationally connected through a hinge, placing holes are formed in the upper surfaces of the two board bodies from top to bottom, plug bodies are arranged on the upper surfaces of the two board bodies, and the bottoms of the two plug bodies are respectively embedded in the two placing holes; through joint drawing paper between two reels, designer is in the time of carrying out artistic designing, when a design is accomplished the back, in the time of need carrying out next artistic designing, directly rotate left cock body, the design of accomplishing this moment can be rolled up on the left reel, the blank drawing paper on the reel of right side can be pulled open to the tiling is on the plate body, avoid designer when carrying out artistic designing, need the inconvenient and reduction work efficiency's that frequent change drawing paper caused the condition.

Description

Folding drawing board for art design

Technical Field

The invention relates to the technical field of art design, in particular to a folding drawing board for art design.

Background

The artistic designing is a conception or plan, and the conception or plan is made to be visual through certain aesthetic concepts and expression manipulations, and is an imaging creation process, which aims to eliminate the factors which are not in line with the use of human beings, thereby satisfying the practical function of the direct demand of human survival and development, when the designer designs the artistic, the folding drawing board is usually used, the traditional folding drawing board is used, the designer needs to lay the drawing paper on the drawing board for use, because the artistic designing process needs to be carried out for many times, the drawing paper is frequently changed, the work efficiency of the designer is easily reduced, and the designer is not convenient to use, in addition, the changed artistic design works can not be well stored, and the damage condition is easily caused.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a folding drawing board for art design, which solves the problems in the background technology.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: a folding drawing board for art design comprises two board bodies which are distributed left and right, the two board bodies are rotatably connected through a hinge, placing holes are formed in the upper surfaces of the two board bodies from top to bottom, plug bodies are arranged on the upper surfaces of the two board bodies, the bottom parts of the two plug bodies are respectively embedded in the two placing holes, the outer surfaces of the two plug bodies are respectively attached to the inner surfaces of the two placing holes, winding drums are arranged on the lower surfaces of the inner parts of the two placing holes, the top ends of the two winding drums are respectively fixedly connected with the centers of the lower surfaces of the two plug bodies, bayonets are respectively arranged on the outer side walls of the two winding drums, penetrating openings are respectively formed in the front surfaces of the two board bodies, the two penetrating openings are respectively communicated with the two placing holes, and the top ends of the two penetrating openings respectively extend to the upper surfaces of the two board bodies, the lateral wall of the winding drum on the right side is wound with drawing paper, one end of the drawing paper is clamped in the bayonet on the right side, the other end of the drawing paper passes through the two penetrating ports and is clamped in the bayonet on the left side, the inner lower surface of the placing hole on the left side is positioned in the winding drum on the left side, the inside of the winding drum on the left side is rotatably connected with a rotating block, the two sides of the rotating block are both provided with clamping grooves, the bottoms of the two sides of the inner side of the winding drum on the left side are uniformly formed with clamping blocks, the two clamping blocks are respectively clamped in the two clamping grooves, the bottom of the rotating block is positioned in the plate body on the left side, a driving gear is fixed in the plate body on the left side, the box body is of a hollow cuboid structure with an opening on the right side, the left end of the driving gear is positioned in the box body, a vertical shaft is rotatably connected in the box body, and a driven gear is fixed at the bottom of the lateral wall of the vertical shaft, the driven gear is in meshed connection with the driving gear, a plurality of driving bevel gears are equidistantly fixed on the outer side wall of the vertical shaft, the outer side wall of the vertical shaft is located above the driven gear from top to bottom, a plurality of transverse shafts are connected to the left side of the plate body in an equidistance manner from top to bottom, driven bevel gears are fixed at one ends, away from the plate body, of the transverse shafts, the driven bevel gears are respectively in meshed connection with the driving bevel gears, fan wheels are fixed on the outer side walls of the transverse shafts, located on the right sides of the driven bevel gears, a plurality of through holes are formed in the left side of the penetrating opening from top to bottom in an equidistance manner, and the left ends of the through holes are communicated with the inside of the box body.

Preferably, two the department all inlays in the middle of the opposite side of plate body and establishes and be fixed with first magnetic stripe, and two the front surface bottom of plate body all inlays and establishes and be fixed with the second magnetic stripe, two first magnetic stripe and two the second magnetic stripe all is opposite sex magnet each other.

Preferably, the cross sections of the clamping block and the clamping groove are both arc-shaped structures.

Preferably, the diameter of the driving gear is five times the diameter of the driven gear.

Preferably, the inside both sides of bayonet socket all are fixed with the rubber strip, two the surface of rubber strip all with the surface of drawing paper is laminated mutually.

Preferably, the rear surface of the plate body is provided with a groove, round holes are formed in the tops of two sides of the inside of the groove, a supporting plate is arranged inside the groove, rotating shafts are fixed to the tops of two sides of the supporting plate, the two opposite ends of each rotating shaft are respectively inserted into the two round holes, rubber sleeves are fixed to the inner surfaces of the round holes, and the inner surfaces of the rubber sleeves are tightly attached to the outer surfaces of the rotating shafts.

Preferably, the bottom of the supporting plate is wrapped with an anti-skid gasket.

Preferably, the top from the top down of plate body is equipped with the standing groove, the inside of standing groove is equipped with the receiver, the receiver is front surface open-ended cavity cuboid structure, just the inside rear surface of receiver is fixed with a plurality of elasticity circles, the spout has been seted up to the inside rear surface of standing groove, the inside sliding connection of spout has the slider, the front surface of slider with the rear surface fixed connection of receiver, the inside upper surface of spout rotates and is connected with the screw rod, the screw rod runs through the slider, and with slider threaded connection, the bottom of screw rod extends to the lower surface of plate body, and be fixed with the knob.

(III) advantageous effects

The invention provides a folding drawing board for art design, which has the following beneficial effects:

(1) when the novel artistic drawing board is used, the drawing paper is clamped between the two winding drums, when a designer carries out artistic design, when one design work is finished and the next artistic work is required to be designed, the plug body on the left side is directly rotated, the finished design work can be wound on the winding drum on the left side at the moment, the blank drawing paper on the winding drum on the right side can be pulled open and tiled on the board body, the problems that inconvenience and reduction of working efficiency are caused due to the fact that the designer needs to frequently replace the drawing paper when carrying out artistic design are avoided, the designed work is directly wound on the winding drum on the left side and located inside the board body, and therefore the work can be better stored, the problem that the work cannot be better stored and the work is easily damaged is avoided.

(2) The reel is arranged in the placing hole through the plug body, the drawing paper between the two reels is arranged on the two reels through the openings in the two reels, and after the drawing paper is used, a designer can conveniently and quickly take the two reels out of the two placing holes, conveniently and quickly take the used drawing paper on the two reels off and replace new drawing paper, so that the reel can be used continuously, and the designer can conveniently and quickly replace the drawing paper.

(3) In the use process of the invention, when a designer finishes the design of rolling a product by rotating the left plug body, the driving gear is driven to rotate, and the driven gear and the vertical shaft on the driven gear are driven to rotate, so that the plurality of transverse shafts and the fan wheels on the transverse shafts can be driven to rotate under the action of the driving bevel gear and the driven bevel gear.

(4) When the drawing board is used, the knob at the bottom of the board body is rotated, so that the screw rod can be driven to rotate, the storage box can move upwards, the storage box can be finally stretched out of the board body, designers can conveniently take tools in the storage box for drawing operation, and when the designers adjust the drawing board to a certain angle for art design, the stretched storage box cannot be retracted into the placing groove again under the action of gravity, and more convenience is brought to the designers for art design operation.

Drawings

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

FIG. 2 is a schematic view of the internal structure of the present invention;

FIG. 3 is a rear view of the present invention;

FIG. 4 is an enlarged view of the structure at A of FIG. 2 according to the present invention;

fig. 5 is a schematic side sectional view of the plate body according to the present invention.

In the figure: 1. a box body; 2. a through hole; 3. a plate body; 4. perforating; 5. a plug body; 6. a storage box; 7. drawing paper; 8. a second magnetic stripe; 9. a driven gear; 10. a drive bevel gear; 11. a vertical axis; 12. a driven bevel gear; 13. a horizontal axis; 14. a fan wheel; 15. placing holes; 16. a reel; 17. a chute; 18. an elastic ring; 19. a placement groove; 20. a bayonet; 21. a rubber strip; 22. a knob; 23. a screw; 24. a first magnetic stripe; 25. a driving gear; 26. a groove; 27. a rotating shaft; 28. a support plate; 29. a circular hole; 30. a rubber sleeve; 31. a non-slip mat; 32. rotating the block; 33. a card slot; 34. a clamping block; 35. a slide block.

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.

As shown in fig. 1 to 5, the present invention provides a technical solution: a folding drawing board for art design comprises two board bodies 3 which are distributed left and right, the two board bodies 3 are rotationally connected through a hinge, placing holes 15 are formed in the upper surfaces of the two board bodies 3 from top to bottom, plug bodies 5 are arranged on the upper surfaces of the two board bodies 3, the bottoms of the two plug bodies 5 are respectively embedded in the two placing holes 15, the outer surfaces of the two plug bodies 5 are respectively attached to the inner surfaces of the two placing holes 15, winding drums 16 are arranged on the lower surfaces of the inner portions of the two placing holes 15, the top ends of the two winding drums 16 are respectively fixedly connected with the centers of the lower surfaces of the two plug bodies 5, bayonets 20 are respectively arranged on the outer side walls of the two winding drums 16, through holes 4 are respectively formed in the front surfaces of the two board bodies 3, the top ends of the two through holes 4 are respectively communicated with the two placing holes 15, drawing paper 7 is wound on the outer side wall of the winding drum 16 on the right side, one end of the drawing paper 7 is clamped inside the bayonet 20 on the right side, the other end passes through two through openings 4 and is clamped in the bayonet 20 on the left side, the lower surface of the inner part of the left side placing hole 15 is positioned inside the left side winding drum 16 and is rotatably connected with a rotating block 32, two sides of the rotating block 32 are both provided with clamping grooves 33, clamping blocks 34 are integrally formed at the bottoms of the two inner sides of the left side winding drum 16, the two clamping blocks 34 are respectively clamped inside the two clamping grooves 33, a driving gear 25 is fixedly arranged at the bottom of the rotating block 32 positioned inside the left side plate body 3, a box body 1 is fixedly arranged at the left side of the left side plate body 3, the box body 1 is of a hollow cuboid structure with an opening at the right side, the left end of the driving gear 25 is positioned inside the box body 1, a vertical shaft 11 is rotatably connected inside the box body 1, a driven gear 9 is fixedly arranged at the bottom of the outer side wall of the vertical shaft 11, the driven gear 9 is in meshed connection with the driving gear 25, a plurality of driving bevel gears 10 are equidistantly fixed above the vertical shaft 11 from top to bottom, the left side of the left plate body 3 is connected with a plurality of transverse shafts 13 in an equidistance rotating mode from top to bottom, one ends, far away from the plate body 3, of the transverse shafts 13 are respectively fixed with driven bevel gears 12, the driven bevel gears 12 are respectively meshed with a plurality of driving bevel gears 10, the outer side walls of the transverse shafts 13 are respectively fixed with fan wheels 14 on the right sides of the driven bevel gears 12, a plurality of through holes 2 are formed in the left side of the inner left side of the left side through hole 4 in an equidistance manner from top to bottom, the left ends of the through holes 2 are communicated with the inner part of the box body 1, when the design tool is used, a designer directly carries out artistic design on drawing paper 7 flatly paved on the two plate bodies 3, after the design work paved on the drawing paper on the two plate bodies 3 is completed, the designer rotates a plug body on the left side at the moment, the designed work can be wound on a winding drum 16 on the left side at the moment, and can drive a driving gear 25 to rotate and can drive a driven gear 9 and a vertical shaft 11 thereon to rotate, under the action of the driving bevel gear 10 and the driven bevel gear 12, the transverse shafts 13 and the fan wheels 14 on the transverse shafts are driven to rotate, so that air flow can be generated and blown out from the through holes 2 in the left side through opening 4, further, finished works can be dried, and therefore, the finished works can be wound and stored better, when the finished works are wound on the left side winding drum 16, the blank drawing paper 7 on the right side winding drum 16 can be gradually pulled open and tiled on the two plate bodies 3, at the moment, a designer can continue to perform art design on the blank drawing paper 7 tiled on the two plate bodies 3, and after the drawing paper is completely used, the designer can directly pull out the two plug bodies 5 and the winding drums 16 on the plug bodies from the two placing holes 15, then the used drawing paper 7 can be pulled down from the two winding drums 16, and the two ends of the new drawing paper 7 are respectively clamped in the bayonets 20 on the two winding drums 16, and the reel 16 on the right side is rotated, so that the drawing paper is rolled on the reel 16 on the right side, and a part of the blank drawing paper 7 is reserved, then the two reels 16 are respectively inserted into the two placing holes 15, so that the reserved blank drawing paper 7 is tiled on the two plate bodies 3, and the designer can continue to use the drawing paper.

Further, department all inlays in the middle of the opposite side of two plate bodies 3 and establishes and is fixed with first magnetic stripe 24, and all inlays to establish and is fixed with second magnetic stripe 8 bottom the front surface of two plate bodies 3, two first magnetic stripes 24 and two second magnetic stripes 8 are all for opposite sex magnet each other, two first magnetic stripes 24, can be when two plate bodies 3 are opened, fix two adsorptions, when avoiding using, two plate bodies 3 rotate each other, influence the condition of using, and two second magnetic stripes 8 can be after two plate bodies 3 are folding, fix two plate bodies 3.

Further, the cross-sections of the latch 34 and the catch groove 33 are circular arc-shaped structures, so that the reel 16 can be conveniently taken out of the placing hole 15, and the reel 16 can be conveniently mounted on the rotating block 32 again.

Further, the diameter of the driving gear 25 is five times the diameter of the driven gear 9, and when the left plug 5 is rotated, the horizontal shaft 13 and the fan wheels 14 thereon are driven to rotate rapidly, and air flow is generated to blow out from the through holes 2.

Further, bayonet socket 20's inside both sides all are fixed with rubber strip 21, and the surface of two rubber strips 21 all laminates mutually with drawing paper 7's surface, avoids when rolling drawing paper 7, and drawing paper 7's one end is deviate from bayonet socket 20's inside easily.

Further, recess 26 has been seted up to the rear surface of plate body 3, round hole 29 has all been seted up at the inside both sides top of recess 26, and the inside of recess 26 is equipped with backup pad 28, the both sides top of backup pad 28 all is fixed with pivot 27, peg graft respectively in the inside of two round holes 29 the back of the body end of two pivot 27, the internal surface of two round holes 29 all is fixed with rubber sleeve 30, the internal surface of rubber sleeve 30 closely laminates with the surface of pivot 27, through rotating backup pad 28 to different angles on, thereby can adjust drawing board 3's inclination, make things convenient for the designer to use, and rubber sleeve 30 can make backup pad 28's angle fix on current angle.

Furthermore, the bottom of the supporting plate 28 is wrapped with an anti-slip gasket 31, so that the situation that the use is affected due to the fact that the whole drawing board slides when the drawing board is used is avoided.

Further, a containing groove 19 is formed in the top of the plate body 3 from top to bottom, a containing box 6 is arranged inside the containing groove 19, the containing box 6 is of a hollow cuboid structure with an open front surface, a plurality of elastic rings 18 are fixed on the inner rear surface of the containing box 6, a sliding groove 17 is formed in the inner rear surface of the containing groove 19, a sliding block 35 is connected inside the sliding groove 17 in a sliding manner, the front surface of the sliding block 35 is fixedly connected with the rear surface of the containing box 6, a screw rod 23 is connected to the inner upper surface of the sliding groove 17 in a rotating manner, the screw rod 23 penetrates through the sliding block 35 and is in threaded connection with the sliding block 35, the bottom end of the screw rod 23 extends to the lower surface of the plate body 3, a knob 22 is fixed, when the drawing tool is used, the screw rod 23 can be driven to rotate by rotating the knob 22 at the bottom of the plate body 3, the containing box 6 can move upwards, the containing box 6 can finally stretch out of the drawing tool from the plate body 3, designers can take the tool for operation, and when the designer mediated the drawing board to certain angle when carrying out fine arts design, the receiver 6 that stretches out under the effect of gravity also can not retract into standing groove 19 once more, makes things convenient for the designer to carry out fine arts design operation more to elasticity circle 18 in the receiver 6 can place different instruments in receiver 6.

In conclusion, the working process of the invention is as follows: when the painting paper rack is used, a designer directly carries out art design on the painting paper 7 flatly laid on the two plate bodies 3, after the design works flatly laid on the painting paper on the two plate bodies 3 are finished, the designer rotates the plug body on the left side at the moment, the designed works are wound on the winding drum 16 on the left side at the moment, the driving gear 25 is driven to rotate at the same time, the driven gear 9 and the vertical shaft 11 on the driven gear can be driven to rotate, the transverse shafts 13 and the fan wheels 14 on the transverse shafts can be driven to rotate under the action of the driving bevel gear 10 and the driven bevel gear 12, air flow can be generated, the air flow is blown out from the through holes 2 in the through hole 4 on the left side, the finished works can be blown out, the finished works can be wound and stored better, when the finished design works are wound on the winding drum 16 on the left side, the blank painting paper 7 on the winding drum 16 on the right side can be gradually pulled apart, and the tiling is on two plate bodys 3, designer continues to continue on tiling on two plate bodys 3 blank drawing paper 7 at this moment and can carry out fine arts design, and after drawing paper all finishes using, designer can directly extract two cock bodies 5 and the reel 16 on it from two place holes 15 this moment, then will finish using drawing paper 7 from two reels 16 go up the unloading can, and with the both ends of new drawing paper 7 joint respectively in bayonet socket 20 on two reels 16, and rotate the reel 16 on right side, make the drawing paper rolling on the reel 16 on right side, and reserve partly blank drawing paper 7, then insert two reels 16 respectively in two place holes 15, make the tiling of drawing paper 7 of reserving can make designer continue to use on two blank plate bodys 3.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, 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 appreciated by those skilled in the art that 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. The utility model provides a folding drawing board for art design, includes plate body (3) that distribute about two, its characterized in that: the two plate bodies (3) are rotatably connected through a hinge, the upper surfaces of the two plate bodies (3) are respectively provided with a placing hole (15) from top to bottom, the upper surfaces of the two plate bodies (3) are respectively provided with a plug body (5), the bottom parts of the two plug bodies (5) are respectively embedded in the two placing holes (15), the outer surfaces of the two plug bodies (5) are respectively attached to the inner surfaces of the two placing holes (15), the inner lower surfaces of the two placing holes (15) are respectively provided with a winding drum (16), the top ends of the two winding drums (16) are respectively fixedly connected with the center of the lower surface of the two plug bodies (5), the outer side walls of the two winding drums (16) are respectively provided with a bayonet (20), the front surfaces of the two plate bodies (3) are respectively provided with a penetrating opening (4), and the two penetrating openings (4) are respectively communicated with the two placing holes (15), the top ends of the two penetrating openings (4) respectively extend to the upper surfaces of the two plate bodies (3), the outer side wall of the winding drum (16) on the right side is wound with drawing paper (7), one end of the drawing paper (7) is clamped in the bayonet (20) on the right side, the other end of the drawing paper penetrates through the two penetrating openings (4) and is clamped in the bayonet (20) on the left side, the lower surface of the inner side of the placing hole (15) on the left side is positioned in the inner side of the winding drum (16) on the left side and is rotatably connected with rotating blocks (32), clamping grooves (33) are formed in the two sides of each rotating block (32), clamping blocks (34) are integrally formed at the bottoms of the two inner sides of the winding drum (16) on the left side, the two clamping blocks (34) are respectively clamped in the two clamping grooves (33), the bottom of each rotating block (32) on the left side is positioned in the inner side of the plate body (3), and a driving gear (25) is fixed in the plate body, the left side of plate body (3) is fixed with box body (1), box body (1) is the hollow cuboid structure of right side open-ended, the left end of driving gear (25) is located the inside of box body (1), the internal rotation of box body (1) is connected with vertical axis (11), the lateral wall bottom of vertical axis (11) is fixed with driven gear (9), driven gear (9) with driving gear (25) meshing connection, the lateral wall of vertical axis (11) is located driven gear (9) top from the top down equidistance is fixed with a plurality of initiative bevel gear (10), the left side of plate body (3) from the top down equidistance rotates and is connected with a plurality of horizontal axle (13), a plurality of one end that horizontal axle (13) kept away from plate body (3) all is fixed with driven bevel gear (12), a plurality of driven bevel gear (12) respectively with a plurality of initiative bevel gear (10) meshing connection, the outer side wall of the transverse shaft (13) is located on the right side of the driven bevel gear (12) and is fixedly provided with a fan wheel (14), the left side of the inside of the penetrating opening (4) is provided with a plurality of through holes (2) at equal intervals from top to bottom, and the left ends of the through holes (2) are communicated with the inside of the box body (1).

2. The foldable drawing board for art design according to claim 1, wherein: two the department all inlays in the middle of the opposite side of plate body (3) and establishes and is fixed with first magnetic stripe (24), and two the front surface bottom of plate body (3) all inlays and establishes and is fixed with second magnetic stripe (8), two first magnetic stripe (24) and two second magnetic stripe (8) are the opposite magnet each other.

3. The foldable drawing board for art design according to claim 1, wherein: the sections of the clamping block (34) and the clamping groove (33) are both arc-shaped structures.

4. The foldable drawing board for art design according to claim 1, wherein: the diameter of the driving gear (25) is five times of that of the driven gear (9).

5. The foldable drawing board for art design according to claim 1, wherein: the inside both sides of bayonet socket (20) all are fixed with rubber strip (21), two the surface of rubber strip (21) all with the surface of drawing paper (7) is laminated mutually.

6. The foldable drawing board for art design according to claim 1, wherein: the rear surface of plate body (3) is seted up flutedly (26), round hole (29) have all been seted up at the inside both sides top of recess (26), just the inside of recess (26) is equipped with backup pad (28), the both sides top of backup pad (28) all is fixed with pivot (27), two the end of carrying on the back of the body of pivot (27) is pegged graft respectively two the inside of round hole (29), two the internal surface of round hole (29) all is fixed with rubber sleeve (30), the internal surface of rubber sleeve (30) with the surface of pivot (27) closely laminates.

7. The folding drawing board for art design according to claim 6, wherein: the bottom of the supporting plate (28) is wrapped with an anti-slip gasket (31).

8. The foldable drawing board for art design according to claim 1, wherein: a placing groove (19) is arranged from top to bottom of the plate body (3), a storage box (6) is arranged in the placing groove (19), the storage box (6) is of a hollow cuboid structure with an opening on the front surface, and a plurality of elastic rings (18) are fixed on the inner rear surface of the storage box (6), a sliding groove (17) is arranged on the rear surface of the inner part of the placing groove (19), a sliding block (35) is connected to the inner part of the sliding groove (17) in a sliding manner, the front surface of the sliding block (35) is fixedly connected with the rear surface of the storage box (6), the upper surface of the inner part of the sliding groove (17) is rotationally connected with a screw rod (23), the screw rod (23) penetrates through the sliding block (35), and with slider (35) threaded connection, the bottom of screw rod (23) extends to the lower surface of plate body (3), and is fixed with knob (22).