CN112172387B - Mathematical modeling teaching aid - Google Patents

Mathematical modeling teaching aid Download PDF

Info

Publication number
CN112172387B
CN112172387B CN202011036226.9A CN202011036226A CN112172387B CN 112172387 B CN112172387 B CN 112172387B CN 202011036226 A CN202011036226 A CN 202011036226A CN 112172387 B CN112172387 B CN 112172387B
Authority
CN
China
Prior art keywords
rod
groove
vertical rod
vertical
teaching aid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202011036226.9A
Other languages
Chinese (zh)
Other versions
CN112172387A (en
Inventor
王林
倪晋波
耿显亚
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anhui University of Science and Technology
Original Assignee
Anhui University of Science and Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Anhui University of Science and Technology filed Critical Anhui University of Science and Technology
Priority to CN202011036226.9A priority Critical patent/CN112172387B/en
Publication of CN112172387A publication Critical patent/CN112172387A/en
Application granted granted Critical
Publication of CN112172387B publication Critical patent/CN112172387B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B43WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43LARTICLES FOR WRITING OR DRAWING UPON; WRITING OR DRAWING AIDS; ACCESSORIES FOR WRITING OR DRAWING
    • B43L11/00Non-circular-curve-drawing instruments

Landscapes

  • Electrically Operated Instructional Devices (AREA)

Abstract

The invention belongs to the technical field of teaching aids, and particularly relates to a mathematical modeling teaching aid which comprises a vertical rod, wherein a containing groove is formed in the side surface of the vertical rod; a transverse rod is arranged in the accommodating groove; one end of the transverse rod is provided with a rotating shaft; the vertical rod is provided with a T-shaped groove; a positioning baffle is arranged in the T-shaped groove in a sliding manner; a first reed is installed in the accommodating groove; silica gel columns are uniformly arranged on the side surfaces of the vertical rods; a sucking disc is arranged on the end face of the silica gel column far away from the vertical rod; length scales are engraved on the vertical rod and the transverse rod; the invention improves the drawing effect and convenience of the teaching aid during use and prolongs the service life of the teaching aid.

Description

Mathematical modeling teaching aid
Technical Field
The invention belongs to the technical field of teaching aids, and particularly relates to a mathematical modeling teaching aid.
Background
Mathematical modeling is an important means for solving actual problems by using mathematical tools, mathematical education not only needs to teach students mathematical knowledge, but also needs to teach students to apply learned knowledge to solve actual problems, and teachers need to be good at modeling mathematical concept rules and problem solving methods in teaching aiming at the clear learning characteristics of a special science popularization system, so that corresponding teaching aids need to be used. This type of teaching aid on the market is various today, can satisfy people's user demand basically, but still has certain weak point, and the teaching aid is not convenient for fix a position the teaching aid in the use, appears sliding easily, influences the drawing effect, and simultaneously, when using, the teaching aid angle modulation is difficult, uses inconveniently.
Some technical schemes also exist in the prior art, such as a Chinese patent with application number CN201820246692.1, the ruler comprises a vertical ruler, two top trundles are fixedly mounted on the upper end of the vertical ruler, two bottom trundles are fixedly mounted on the lower end of the vertical ruler, a top sliding groove is formed in the upper end of each top trundle, a bottom sliding groove is formed in the lower end of each bottom trundle, a blackboard is fixedly connected between the top sliding groove and the inner side of the bottom sliding groove and is close to the back of the vertical ruler, and an auxiliary ruler groove is formed in the middle of the back of the vertical ruler; can realize the location of teaching aid on the blackboard in this scheme, however, teaching aid and blackboard exist as an organic whole, can not separate teaching aid and blackboard, and the teacher can not carry the teaching aid and leaves, leads to the teaching aid to use in fixed classroom, and is comparatively inconvenient.
Disclosure of Invention
The invention provides a mathematical modeling teaching aid, which aims to make up the defects of the prior art and solve the problems of inconvenient positioning and difficult adjustment of the angle of the teaching aid in the using process.
The technical scheme adopted by the invention for solving the technical problems is as follows: the mathematical modeling teaching aid comprises a vertical rod, wherein a containing groove is formed in the side surface of the vertical rod; a transverse rod is arranged in the accommodating groove; the length of the accommodating groove is greater than that of the transverse rod; the upper bottom surface and the lower bottom surface of the accommodating groove are provided with sliding grooves; one end of the transverse rod is provided with a rotating shaft; the rotating shaft is arranged in the sliding groove; the rotating shaft can rotate in the sliding groove and can move back and forth in the sliding groove; the vertical rod is provided with a T-shaped groove; a positioning baffle is arranged in the T-shaped groove in a sliding manner; the T-shaped groove is positioned on the vertical rod and close to the opening of the accommodating groove, and the side surface of the T-shaped groove is perpendicular to the side surface of the opening of the accommodating groove; the positioning baffle piece can prevent the transverse rod from moving outwards the accommodating groove; a first reed is installed in the accommodating groove; the distance between the first reed and the accommodating groove opening is smaller than the distance between the transverse rod and the accommodating groove opening; the first reed and the positioning blocking piece are positioned at the same end of the vertical rod, and rotating shafts of the first reed and the transverse rod are respectively positioned at two ends of the vertical rod; silica gel columns are uniformly arranged on the side surfaces of the vertical rods; the side face where the silica gel column is located is opposite to the side face where the T-shaped groove is located, and the silica gel column is in contact with the blackboard surface; a sucking disc is arranged on the end face of the silica gel column far away from the vertical rod; length scales are engraved on the vertical rod and the transverse rod;
when the teaching aid is in work, when a teacher needs to draw a model curve in the teaching process, the teacher moves the positioning blocking piece, the blocking effect of the positioning blocking piece on the transverse rod is removed, the transverse rod can move and rotate in the accommodating groove, so that the transverse rod can be pulled out from the vertical rod and forms a right angle with the vertical rod, the teaching aid is convenient for the teacher to use, meanwhile, after the transverse rod is pulled out from the vertical rod, the teacher presses the teaching aid on the board surface of the blackboard, the silica gel column on the vertical rod and the sucking disc on the end surface of the silica gel column are in contact with the board surface of the blackboard, so that the teaching aid is fixed on the board surface to a certain extent, the teacher does not need to put more attention on the teaching aid in the curve drawing process, the sliding of the teaching aid is prevented, meanwhile, the positioning of the teaching aid on the blackboard in the drawing process is convenient, and the time spent by the teacher in adjusting the deviation caused by the sliding of the teaching aid in the use process is eliminated, the speed of a teacher drawing a model curve is increased, the effect of drawing the model curve is improved, meanwhile, the transverse rod can rotate and move relative to the vertical rod, so that the teacher can conveniently adjust the angle of a teaching aid when drawing the model curve, the convenience of the teacher in the use process is improved, the speed of drawing the model curve by the teacher is increased, meanwhile, the positioning blocking piece on the vertical rod can mark the scale on the vertical rod when the teacher uses the teaching aid to draw, the error caused by the large thickness of the vertical rod is avoided, meanwhile, in the use process, the teacher places the vertical rod on the position of the blackboard where the curve needs to be drawn, then the vertical rod and the transverse rod are used for drawing a vertical axis and a transverse axis, then the position of the transverse rod is adjusted, and the characteristic point coordinates of the curve are sequentially found and marked according to the scale on the vertical rod and the transverse rod, after the mark is accomplished, take the teaching aid away, connect gradually the characteristic point, draw and obtain the model curve, simultaneously, because in the holding tank on the vertical pole can be taken in to the horizontal pole, when the teacher need not use the teaching aid, the space that the reduction teaching aid that can be very big took, the carrying and the storage of the teaching aid of being convenient for.
Preferably, small suckers are uniformly arranged on the inner surface of the sucker; a communicating hole is formed in the sucker; the small suckers are connected with each other through the communication holes;
during operation, silica gel column contacts blackboard surface after, the little sucking disc in the sucking disc on the silica gel column terminal surface contacts blackboard surface equally, increases area of contact between silica gel column and the blackboard through little sucking disc, promotes the dynamics that the teaching aid is fixed on the blackboard, avoids the teaching aid to appear sliding, simultaneously, can guarantee through little sucking disc that the teaching aid also has good fixed effect when blackboard surface unevenness, avoids the teaching aid can not normally be used on the relatively poor blackboard of surface quality.
Preferably, the vertical rod is provided with a first mounting cavity; the opening of the first mounting cavity and the silica gel column are positioned on the same side face; the number of the installation cavities is two, and the installation cavities are respectively positioned at two ends of the vertical rod; a guide wheel is arranged in the first mounting cavity; the guide wheels are divided into two groups and are respectively positioned in the first mounting cavities; four guide wheels are arranged in each group, and the guide wheels are arranged in a rectangular shape; the length direction of a rectangle formed by the guide wheels is vertical to the length direction of the vertical rod; a first fixing frame and a second fixing frame are mounted on a rotating shaft of the guide wheel, and the guide wheel is positioned between the first fixing frame and the second fixing frame; the distance between the first fixing frame and the end surface of the vertical rod is smaller than the distance between the second fixing frame and the end surface of the vertical rod; the upper end of the second fixing frame extends out of the surface of the vertical rod, and the second fixing frame can move freely; the upper end of the second fixing frame and the T-shaped groove are located on the same side face; the upper end of the second fixing frame is provided with a pressing rod; two ends of the pressing rod are fixedly connected with the two second fixing frames respectively; the vertical rod is provided with a second mounting cavity; the mounting cavity II is located right below the vertical rod, and the pressing rod can enter the mounting cavity II; a second reed is arranged on the bottom surface of the second mounting cavity; the second reed pushes the pressing rod outwards from the installation cavity;
when the teaching aid works, when a teacher draws a complete model curve or needs to move the position of the teaching aid, the teacher presses the pressing rod on the vertical rod to press the pressing rod into the second installation cavity, the fixing frame moves towards the surface of the blackboard when the pressing rod moves, so that the guide wheel protrudes out of the first installation cavity, and further the guide wheel contacts with the surface of the blackboard, meanwhile, after the guide wheel contacts with the surface of the blackboard, the silica gel column is separated from the surface of the blackboard, the fixing of the teaching aid is released, then, the teacher can freely push the vertical rod to move to a target position along the surface of the blackboard, then, the teacher loosens the pressing rod, under the action of the second reed in the second installation cavity, the pressing rod returns to the original position, so that the second fixing frame is driven to be away from the blackboard, the guide wheel is not contacted with the blackboard any more, meanwhile, after the guide wheel is retracted, the guide wheel is contacted with the surface of the blackboard again, and passes through the sucker on the end surface of the silica gel column, fix the teaching aid again on the blackboard, simultaneously, because the guide pulley in every installation cavity is one all has a plurality ofly, consequently, receives teacher's promotion at the teaching aid, along blackboard surface motion's in-process, the motion path of vertical pole is a straight line, can guarantee the removal back of teaching aid on the emergence position, and the abscissa axis is still collinear to guarantee that the teacher passes through the accuracy of the model curve that the teaching aid drawn, promote and draw the effect.
Preferably, a compression cavity is formed in the vertical rod; the compression cavity is positioned right below the pressing rod; a movable plate is arranged in the compression cavity; the second fixing frame is provided with a magnetic block; the magnetic block is magnetically connected with the movable plate; an installation groove is formed in the vertical rod; the magnetic block is positioned in the mounting groove and can freely move in the mounting groove; the space in the compression cavity below the movable plate is communicated to a communicating hole on the silica gel column through a pipeline;
when the teaching aid works, the teaching aid is moved, after a teacher looses the pressing rod, the pressing rod returns to the original position under the action of the second reed, meanwhile, the pressing rod drives the fixed frame to move towards the direction far away from the surface of the blackboard, the magnetic block is driven to move through the movement of the second fixed frame, and the magnetic block is magnetically connected with the movable plate, so that the movable block and the second fixed frame synchronously move, the space below the movable plate in the compression cavity is gradually enlarged in the process of withdrawing the guide wheel, the pressure in the space is reduced to generate negative pressure, and the space below the movable plate in the compression cavity is communicated with the sucker on the silica gel column, so that the sucker gradually contacts the surface of the blackboard and is firmly adsorbed on the surface in the process of withdrawing the guide wheel, the situation that the teacher needs to manually exert pressure on the vertical rod after loosening the pressing rod is avoided, and the teaching aid can be firmly adsorbed on the blackboard, simultaneously, can guarantee that the sucking disc is in the negative pressure adsorption state all the time when the guide pulley is withdrawed, avoid the teaching aid because the unexpected condition appears dropping, the model curve effect that leads to the teacher to draw is not good.
Preferably, a third mounting cavity is formed in the rotating shaft; an air bag is arranged in the mounting cavity III; a top block is arranged in the mounting cavity III; the top block is positioned above the air bag; clamping columns are uniformly arranged in the side wall of the mounting cavity III and can move freely; the upper end of the top block is conical, and the conical surface is contacted with one end of the clamping column in the third mounting cavity; the clamping column is connected with the top block through a string; the other end of the clamping column is tightly attached to the side surface of the sliding groove; the upper end of the mounting cavity III is provided with a push rod; the lower end of the push rod is in contact with the upper surface of the top block, and the upper end of the push rod extends out of the vertical rod; the push rod can move freely; the vertical rod is provided with a guide groove; the push rod is positioned in the guide groove and can freely move along the guide groove;
when the teaching aid works, when a teacher needs to adjust the angle of the teaching aid, the teacher presses the push rod manually, and when the push rod is pressed into the third installation cavity, the pressed push rod extrudes the ejector block to move the ejector block downwards and compress the airbag at the same time, because the top block is connected with the clamping column through the string, the clamping column retracts towards the third installation cavity to unlock the rotating shaft in the process that the top column moves downwards, and then a teacher can easily rotate the transverse rod to adjust the angle of the teaching aid, meanwhile, after the adjustment is finished, the teacher loosens the extrusion on the push rod, the acting force between the push rod and the ejector block disappears, the ejector block returns to the original position under the action of the air bag, the clamping column is pushed out of the mounting cavity III again, the locking on the rotating shaft is finished, and the situation that in the use process is avoided, the transverse rod rotates, so that the teacher draws a curve with deviation, and the final drawing effect is influenced.
Preferably, a first groove is formed in the middle of the vertical rod; the first groove and the T-shaped groove are located on the same side face; the surface of the first groove is sealed by a transparent panel; the edge of the first groove is provided with angle scales; a mounting rod is arranged at the center of the inner part of the first groove; a homogenizing rod is rotatably arranged on the mounting rod; the mounting rod is positioned in the middle of the homogenizing rod; a second groove is formed in the middle of the transverse rod; the second groove is positioned on the lateral surface, close to the first groove, of the transverse rod, and the lateral surface where the second groove is positioned is parallel to the lateral surface where the first groove is positioned; the surface of the second groove is sealed by a transparent panel; the edge of the second groove is provided with angle scales; a mounting rod is arranged at the center position in the second groove; a homogenizing rod is rotatably arranged on the mounting rod;
when the teaching aid works, after a teacher places the teaching aid on the surface of a blackboard, the homogenizing rod in the first groove on the vertical rod keeps balance due to the lever principle, namely the horizontal state is unchanged, meanwhile, the homogenizing rod is rotatably installed on the installation rod, so that when the vertical rod cannot keep the vertical state in the plane of the blackboard surface, an included angle exists between the homogenizing rod and the scale on the edge of the first groove, the teacher can easily identify the included angle between the vertical rod and the vertical direction, further adjust the position of the vertical rod, keep the vertical rod in the vertical state, avoid errors in drawing characteristic points of a curve due to the included angle between the vertical rod and the vertical direction, reduce the accuracy of the model curve and influence the final drawing effect, and meanwhile, the teaching aid can be obtained in the same way, the homogenizing rod arranged in the second groove can show the included angle between the transverse rod and the horizontal direction, and then be convenient for the teacher to adjust the transverse bar position, the time transverse bar keeps the level, promote the degree of accuracy that the model curve was drawn, promote and draw the effect, and simultaneously, contained angle between the vertical pole and the vertical direction of the homogeneity pole show in the recess one, can make the teacher audio-visual vertical motion state of perceiving when removing vertical pole, keep vertical pole to be in vertical state all the time, avoid vertical pole remove the back and vertical direction between the contained angle appear, influence the effect that the model curve that the teacher drawn.
Preferably, the vertical rods and the transverse rods are obtained by bonding multiple layers of plastic sheets; a thin steel sheet is arranged between the vertical rod and the transverse rod;
during operation, through the mode that sets up the sheet steel, can promote the intensity and the toughness of horizontal pole and vertical pole, guarantee in the use, crooked or rupture can not appear in the teaching aid, influence the use and the accuracy of teaching aid, from the life who prolongs the teaching aid.
The invention has the following beneficial effects:
1. according to the mathematical modeling teaching aid, the vertical rod, the transverse rod and the silica gel column are arranged, so that the space occupied by the teaching aid can be effectively reduced, the carrying and the storage of the teaching aid are facilitated, and meanwhile, the positioning stability of the teaching aid relative to a blackboard and the slippage of the teaching aid can be effectively ensured in the use process of the teaching aid through the silica gel column and the suckers on the end faces of the silica gel column, so that the speed of a teacher drawing a model curve is increased, and the phenomenon that the accuracy and the effect of the model curve drawn by the teacher are influenced due to the slippage of the teaching aid in the curve drawing process of the teacher is avoided.
2. According to the mathematical modeling teaching aid, the first groove, the second groove, the mounting rod and the homogenizing rod are arranged, so that included angles between the teaching aid at the position on the plane where the blackboard is located and the vertical direction and the horizontal direction can be clearly and conveniently displayed, a teacher can conveniently adjust the position of the teaching aid, the vertical rod and the transverse rod can be ensured to be overlapped with coordinate axes, and the phenomenon that the drawn model curve has large errors and the effect of the model curve drawn by the teacher is influenced is avoided.
Drawings
The invention will be further explained with reference to the drawings.
FIG. 1 is a schematic diagram of the construction of the teaching aid of the present invention;
FIG. 2 is a partial cross-sectional view of the teaching aid of the present invention;
FIG. 3 is a schematic diagram of a silica gel column chuck;
FIG. 4 is an enlarged view of a portion of FIG. 1 at A;
FIG. 5 is an enlarged view of a portion of FIG. 1 at B;
in the figure: the device comprises a vertical rod 1, an accommodating groove 11, a first reed 111, a guide groove 12, a sliding groove 13, a first mounting cavity 14, a guide wheel 141, a first fixing frame 142, a second fixing frame 143, a pressing rod 144, a second reed 145, a compression cavity 15, a movable plate 151, a magnetic block 152, a mounting groove 16, a first groove 17, a mounting rod 171, a homogenizing rod 172, a T-shaped groove 18, a positioning baffle 181, a transverse rod 2, a rotating shaft 21, an air bag 211, a clamping column 212, a top block 213, a pushing rod 214, a second groove 22, a silica gel column 3, a small suction cup 31 and a communicating hole 32.
Detailed Description
In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.
As shown in fig. 1 to 5, the mathematical modeling teaching aid of the present invention includes a vertical rod 1, wherein a side surface of the vertical rod 1 is provided with an accommodating groove 11; the transverse rod 2 is arranged in the accommodating groove 11; the length of the receiving groove 11 is greater than that of the transverse bar 2; the upper bottom surface and the lower bottom surface of the accommodating groove 11 are provided with sliding grooves 13; one end of the transverse rod 2 is provided with a rotating shaft 21; the rotating shaft 21 is installed in the sliding groove 13; the rotating shaft 21 can rotate in the sliding groove 13, and the rotating shaft 21 can move back and forth in the sliding groove 13; the vertical rod 1 is provided with a T-shaped groove 18; a positioning baffle 181 is arranged in the T-shaped groove 18 in a sliding manner; the T-shaped groove 18 is positioned on the vertical rod 1 and close to the opening of the accommodating groove 11, and the side surface of the T-shaped groove 18 is perpendicular to the side surface of the opening of the accommodating groove 11; the positioning baffle 181 can prevent the transverse rod 2 from moving out of the accommodating groove 11; a first reed 111 is installed in the accommodating groove 11; the distance between the first reed 111 and the opening of the accommodating groove 11 is smaller than the distance between the transverse rod 2 and the opening of the accommodating groove 11; the first reed 111 and the positioning baffle 181 are positioned at the same end of the vertical rod 1, and the first reed 111 and the rotating shaft 21 of the transverse rod 2 are respectively positioned at two ends of the vertical rod 1; silica gel columns 3 are uniformly arranged on the side surface of the vertical rod 1; the side surface of the silica gel column 3 is opposite to the side surface of the T-shaped groove 18, and the silica gel column 3 is contacted with the blackboard surface; a sucking disc is arranged on the end face of the silica gel column 3 far away from the vertical rod 1; length scales are engraved on the vertical rod 1 and the transverse rod 2;
when the teaching aid is in work, when a teacher needs to draw a model curve in the teaching process, the teacher moves the positioning blocking piece 181, the blocking effect of the positioning blocking piece 181 on the transverse rod 2 is removed, the transverse rod 2 can move and rotate in the accommodating groove 11, so that the transverse rod 2 can be pulled out from the vertical rod 1 and forms a right angle with the vertical rod 1, the teaching aid is convenient for the teacher to use, meanwhile, after the transverse rod 2 is pulled out from the vertical rod 1, the teacher presses the teaching aid on the board surface of the blackboard, the silica gel column 3 on the vertical rod 1 and the sucking disc on the end surface of the silica gel column 3 are in contact with the board surface of the blackboard, so that the teaching aid is fixed on the board surface to a certain extent, the teacher does not need to bet more attention on the teaching aid in the process of drawing the curve, the sliding of the teaching aid is prevented, meanwhile, the positioning of the teaching aid on the blackboard in the drawing process is convenient, and the time spent on adjusting the deviation caused by the sliding of the teaching aid in the use process is eliminated, the speed of a teacher drawing a model curve is increased, the effect of drawing the model curve is improved, meanwhile, the transverse rod 2 can rotate and move relative to the vertical rod 1, so that the teacher can conveniently adjust the angle of a teaching aid when drawing the model curve, the convenience of the teacher in the use process is improved, the speed of drawing the model curve by the teacher is increased, meanwhile, the positioning blocking piece 181 on the vertical rod 1 can mark the scale on the vertical rod 1 when the teacher uses the teaching aid to draw, the error caused by the large thickness of the vertical rod 1 is avoided, meanwhile, in the use process, the teacher places the vertical rod 1 on a blackboard at the position where the curve needs to be drawn, then the vertical rod 1 and the transverse rod 2 are used for drawing the vertical axis and the transverse axis, then the position of the transverse rod 2 is adjusted, the characteristic point coordinates of the curve are sequentially found and marked according to the scales on the vertical rod 1 and the transverse rod 2, after the mark is accomplished, take the teaching aid away, connect gradually the characteristic point, draw and obtain the model curve, simultaneously, because horizontal pole 2 can take in to the holding tank 11 on vertical pole 1 in, when the teacher need not use the teaching aid, the space that the teaching aid occupy that reduces that can be very big, the carrying and the storage of the teaching aid of being convenient for.
As an embodiment of the present invention, small suction cups 31 are uniformly arranged on the inner surface of the suction cup; a communicating hole 32 is formed in the sucking disc; the small suction cups 31 are connected with each other through communication holes 32;
during operation, silica gel column 3 contacts after the blackboard surface, little sucking disc 31 in the sucking disc on the 3 terminal surfaces of silica gel column contacts the blackboard surface equally, increase the area of contact between silica gel column 3 and the blackboard through little sucking disc 31, promote the dynamics that the teaching aid is fixed on the blackboard, avoid the teaching aid to appear sliding, and simultaneously, can guarantee through little sucking disc 31 that the teaching aid also has good fixed effect when blackboard surface unevenness, avoid the teaching aid can not normally be used on the relatively poor blackboard of surface quality.
As an embodiment of the invention, the vertical rod 1 is provided with a first mounting cavity 14; the opening of the first mounting cavity 14 and the silica gel column 3 are positioned on the same side; the first mounting cavities 14 are two in number and are respectively positioned at two ends of the vertical rod 1; a guide wheel 141 is arranged in the first mounting cavity 14; the guide wheels 141 are divided into two groups and are respectively positioned in the first two mounting cavities 14; four guide wheels 141 are arranged in each group, and the guide wheels 141 are arranged in a rectangular shape; the length direction of the rectangle formed by the guide wheels 141 is vertical to the length direction of the vertical rod 1; a first fixing frame 142 and a second fixing frame 143 are mounted on a rotating shaft of the guide wheel 141, and the guide wheel 141 is located between the first fixing frame 142 and the second fixing frame 143; the distance between the first fixing frame 142 and the end face of the vertical rod 1 is smaller than the distance between the second fixing frame 143 and the end face of the vertical rod 1; the upper end of the second fixing frame 143 extends out of the surface of the vertical rod 1, and the second fixing frame 143 can move freely; the upper end of the second fixing frame 143 is positioned on the same side face as the T-shaped groove 18; the upper end of the second fixing frame 143 is provided with a pressing rod 144; two ends of the pressing rod 144 are fixedly connected with the two second fixing frames 143 respectively; the vertical rod 1 is provided with a second mounting cavity; the mounting cavity II is positioned right below the vertical rod 1, and the pressing rod 144 can enter the mounting cavity II; a second reed 145 is installed on the bottom surface of the second installation cavity; the second reed 145 pushes the pressing rod 144 outwards from the installation cavity;
in operation, when a teacher draws a model curve or needs to move the position of the teaching aid, the teacher presses the pressing rod 144 on the vertical rod 1 to press the pressing rod 144 into the second installation cavity, the second fixing frame 143 moves towards the surface of the blackboard when the pressing rod 144 moves, so that the guide wheel 141 protrudes out of the first installation cavity 14, and the guide wheel 141 contacts with the surface of the blackboard, and meanwhile, after the guide wheel 141 contacts with the surface of the blackboard, the silica gel column 3 is separated from the surface of the blackboard, and the fixing of the teaching aid is released, and then the teacher can freely push the vertical rod 1 to move to a target position along the surface of the blackboard, and then the teacher releases the pressing rod 144, and under the action of the second reed 145 in the second installation cavity, the pressing rod 144 returns to the original position, so that the second fixing frame 143 is driven to be away from the blackboard, the guide wheel 141 is not contacted with the blackboard any more, and meanwhile, after the guide wheel 141 is retracted, the silica gel column 3 is contacted with the surface again, through the sucking disc on 3 terminal surfaces of silica gel column, fix the teaching aid again on the blackboard, simultaneously, because guide pulley 141 in every installation cavity 14 all has a plurality ofly, consequently, receive teacher's promotion at the teaching aid, along the in-process of blackboard surface motion, the motion route of vertical pole 1 is a straight line, can guarantee the removal back of teaching aid on the emergence position, the abscissa axle is still collinear, thereby guarantee that the teacher passes through the accuracy of the model curve that the teaching aid drawn, promote and draw the effect.
As an embodiment of the present invention, a compression cavity 15 is formed in the vertical rod 1; the compression cavity 15 is positioned right below the pressing rod 144; a movable plate 151 is installed in the compression chamber 15; a magnetic block 152 is arranged on the second fixing frame 143; a magnetic connection exists between the magnetic block 152 and the movable plate 151; an installation groove 16 is formed in the vertical rod 1; the magnetic block 152 is positioned in the installation groove 16, and the magnetic block 152 can move freely in the installation groove 16; the space in the compression cavity 15 below the movable plate 151 is communicated to the communicating hole 32 on the silica gel column 3 through a pipeline;
when the teaching aid works, after a teacher looses the pressing rod 144, the pressing rod 144 returns to the original position under the action of the second reed 145, meanwhile, the pressing rod 144 drives the second fixed frame 143 to move towards the direction far away from the surface of the blackboard, the magnetic block 152 is driven to move through the movement of the second fixed frame 143, and because the magnetic block 152 is magnetically connected with the movable plate 151, the movable block and the second fixed frame 143 move synchronously, so that the space below the movable plate 151 in the compression cavity 15 is gradually enlarged in the process of withdrawing the guide wheel 141, the pressure in the space is reduced, negative pressure is generated, and because the space below the movable plate 151 in the compression cavity 15 is communicated with the suction cup on the silica gel column 3, the suction cup gradually contacts the surface of the blackboard and is firmly adsorbed on the surface of the blackboard, the situation that the teacher needs to manually press the vertical rod 1 after loosening the pressing rod 144 is avoided, guarantee that the teaching aid can firmly adsorb on the blackboard, simultaneously, can guarantee that the sucking disc is in the negative pressure adsorption state all the time when guide pulley 141 withdraws, avoid the teaching aid because the unexpected condition appears dropping, the model curve effect that leads to the teacher to draw is not good.
As an embodiment of the present invention, a third installation cavity is formed in the rotating shaft 21; an air bag 211 is arranged in the mounting cavity III; a top block 213 is arranged in the third mounting cavity; the top block 213 is positioned above the airbag 211; clamping columns 212 are uniformly arranged in the side wall of the mounting cavity III, and the clamping columns 212 can move freely; the upper end of the top block 213 is conical, and the conical surface is contacted with one end of the clamping column 212 in the third installation cavity; the clamping column 212 is connected with the top block 213 through a string; the other end of the clamping column 212 is tightly attached to the side surface of the sliding groove 13; the upper end of the third mounting cavity is provided with a push rod 214; the lower end of the push rod 214 is contacted with the upper surface of the top block 213, and the upper end extends out of the vertical rod 1; the push rod 214 can move freely; the vertical rod 1 is provided with a guide groove 12; the push rod 214 is positioned in the guide groove 12, and the push rod 214 can freely move along the guide groove 12;
in operation, when a teacher needs to adjust the angle of the teaching aid, the teacher presses the push rod 214 manually, when the push rod 214 is pressed into the third installation cavity, the pressed push rod 214 presses the top block 213 to move the top block 213 downwards and compress the airbag 211, and the top block 213 is connected with the clamping column 212 through the string, so that the clamping column 212 retracts into the third installation cavity to unlock the rotating shaft 21 in the downward moving process of the top column, and then the teacher can easily rotate the transverse rod 2 to adjust the angle of the teaching aid, and after the adjustment is completed, and after the teacher releases the pressing on the push rod 214, the acting force between the push rod 214 and the top block 213 disappears, the top block 213 returns to the original position under the action of the airbag 211 to push the clamping column 212 out of the third installation cavity again to lock the rotating shaft 21, so that the transverse rod 2 does not rotate in the use process, the teacher is led to draw the curve and have deviation, and the final drawing effect is influenced.
As an embodiment of the invention, a first groove 17 is formed in the middle of the vertical rod 1; the first groove 17 and the T-shaped groove 18 are positioned on the same side face; the surface of the first groove 17 is sealed by a transparent panel; the edge of the first groove 17 is provided with angle scales; a mounting rod 171 is arranged at the center position in the first groove 17; a homogenizing rod 172 is rotatably mounted on the mounting rod 171; the mounting rod 171 is located at the middle position of the homogenizing rod 172; a second groove 22 is formed in the middle of the transverse rod 2; the second groove 22 is positioned on the lateral surface, close to the first groove 17, of the transverse rod 2, and the lateral surface where the second groove 22 is positioned is parallel to the lateral surface where the first groove 17 is positioned; the surface of the second groove 22 is sealed by a transparent panel; the edge of the second groove 22 is provided with angle scales; a mounting rod 171 is mounted at the center position in the second groove 22; a homogenizing rod 172 is rotatably mounted on the mounting rod 171;
when the teaching aid works, after a teacher places the teaching aid on the surface of a blackboard, the homogenizing rod 172 in the groove I17 on the vertical rod 1 keeps balance due to the lever principle, namely the horizontal state is unchanged, meanwhile, because the homogenizing rod 172 is rotatably installed on the installation rod 171, when the vertical rod 1 cannot keep the vertical state in the plane of the blackboard surface, an included angle exists between the homogenizing rod 172 and the scale on the edge of the groove I17, the teacher can easily identify the included angle between the vertical rod 1 and the vertical direction, further adjust the position of the vertical rod 1, keep the vertical rod 1 in the vertical state, avoid errors caused by the included angle between the vertical rod 1 and the vertical direction when drawing characteristic points of a curve, reduce the accuracy of the model curve and influence the final drawing effect, and meanwhile, the teaching aid can be obtained in the same way, the homogenizing rod 172 arranged in the groove II 22 can show the included angle between the transverse rod 2 and the horizontal direction, and then be convenient for the teacher to adjust 2 positions of horizontal pole, time horizontal pole 2 keeps the level, promote the degree of accuracy that the model curve was drawn, promote and draw the effect, and simultaneously, contained angle between vertical pole 1 and the vertical direction through the homogeneity pole 172 show in recess 17, can make the teacher audio-visual vertical motion state of perceiving when removing vertical pole 1, keep vertical pole 1 to be in vertical state all the time, avoid vertical pole 1 to remove the back and the vertical direction between the contained angle appears, influence the effect that the model curve that the teacher drawn.
As an embodiment of the invention, the vertical rods 1 and the transverse rods 2 are both made of multiple layers of plastic sheets; a thin steel sheet is arranged between the vertical rod 1 and the transverse rod 2;
during operation, through the mode that sets up the sheet steel, can promote the intensity and the toughness of horizontal pole 2 and vertical pole 1, guarantee in the use, crooked or rupture can not appear in the teaching aid, influence the use and the accuracy of teaching aid, from the life who prolongs the teaching aid.
The specific working process is as follows:
when the teaching aid works, when a teacher needs to draw a model curve in the teaching process, the teacher moves the positioning blocking piece 181, the blocking effect of the positioning blocking piece 181 on the transverse rod 2 is removed, the transverse rod 2 can move and rotate in the accommodating groove 11, so that the transverse rod 2 can be pulled out of the vertical rod 1 to form a right angle with the vertical rod 1, and meanwhile, after the transverse rod 2 is pulled out of the vertical rod 1, the teacher presses the teaching aid on the board surface of the blackboard, so that the silica gel column 3 on the vertical rod 1 and the sucking disc on the end surface of the silica gel column 3 are in contact with the board surface of the blackboard; after the silica gel column 3 is contacted with the surface of the blackboard, a small suction cup 31 in a suction cup on the end surface of the silica gel column 3 is also contacted with the surface of the blackboard, and the contact area between the silica gel column 3 and the blackboard is increased through the small suction cup 31; when a teacher draws a finished model curve or needs to move the position of the teaching aid, the teacher presses the pressing rod 144 on the vertical rod 1 to press the pressing rod 144 into the second mounting cavity, the second fixing frame 143 moves towards the surface of the blackboard when the pressing rod 144 moves, so that the guide wheel 141 protrudes out of the first mounting cavity 14, and the guide wheel 141 is in contact with the surface of the blackboard, meanwhile, after the guide wheel 141 is in contact with the surface of the blackboard, the silica gel column 3 is separated from the surface of the blackboard, the fixing of the teaching aid is released, then, the teacher can freely push the vertical rod 1 to move to a target position along the surface of the blackboard, then, the teacher releases the pressing rod 144, under the action of the second reed 145 in the second mounting cavity, the pressing rod 144 returns to the original position, so that the second fixing frame 143 is driven to be far away from the guide wheel 141, the guide wheel 141 is not in contact with the guide wheel, meanwhile, after the second fixing frame 141 is retracted, the silica gel column 3 is in contact with the surface of the blackboard again, the teaching aid is fixed on the blackboard again through a sucker on the end surface of the silica gel column 3; after the teaching aid finishes moving, and a teacher loosens the pressing rod 144, the pressing rod 144 returns to the original position under the action of the second reed 145, meanwhile, the pressing rod 144 drives the second fixed frame 143 to move towards the direction away from the surface of the blackboard, the second fixed frame 143 moves to drive the magnetic block 152 to move, and the magnetic block 152 is magnetically connected with the second movable plate 151, so that the movable block and the second fixed frame 143 synchronously move, the space below the second movable plate 151 in the compression cavity 15 is gradually expanded in the process of withdrawing the guide wheel 141, the pressure in the space is reduced, negative pressure is generated, and the space below the second movable plate 151 in the compression cavity 15 is communicated with the sucker on the silica gel column 3, so that the sucker gradually contacts the surface of the blackboard in the process of withdrawing the guide wheel 141; when a teacher needs to adjust the angle of the teaching aid, the teacher presses the push rod 214 manually, when the push rod 214 is pressed into the third mounting cavity, the pressed push rod 214 presses the top block 213 to move the top block 213 downwards and compress the airbag 211, and the top block 213 is connected with the jack 212 through the string, so that the jack 212 retracts into the third mounting cavity to unlock the rotating shaft 21 in the downward movement process of the jack, and after the teacher releases the pressing of the push rod 214 after the adjustment is completed, the acting force between the push rod 214 and the top block 213 disappears, the jack 213 returns to the original position under the action of the airbag 211 to push the jack 212 out of the third mounting cavity again to complete the locking of the rotating shaft 21; after the teacher places the teaching aid on the surface of the blackboard, the homogenizing rod 172 in the groove I17 on the vertical rod 1 keeps balance due to the lever principle, namely the horizontal state is unchanged, meanwhile, the homogenizing rod 172 is rotatably installed on the installation rod 171, so that when the vertical rod 1 cannot keep the vertical state in the plane of the blackboard surface, an included angle exists between the homogenizing rod 172 and the scale on the edge of the groove I17, and meanwhile, the homogeneous rod 172 arranged in the groove II 22 can show the included angle between the transverse rod 2 and the horizontal direction; the strength and toughness of the transverse rod 2 and the vertical rod 1 are improved by arranging the thin steel sheets.
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (7)

1. The utility model provides a mathematical modeling teaching aid, includes vertical pole (1), its characterized in that: the side surface of the vertical rod (1) is provided with a containing groove (11); a transverse rod (2) is arranged in the accommodating groove (11); the length of the accommodating groove (11) is greater than that of the transverse rod (2); the upper bottom surface and the lower bottom surface of the accommodating groove (11) are provided with sliding grooves (13); one end of the transverse rod (2) is provided with a rotating shaft (21); the rotating shaft (21) is installed in the sliding groove (13); the rotating shaft (21) can rotate in the sliding groove (13), and the rotating shaft (21) can move back and forth in the sliding groove (13); the vertical rod (1) is provided with a T-shaped groove (18); a positioning baffle plate (181) is arranged in the T-shaped groove (18) in a sliding manner; the T-shaped groove (18) is positioned on the vertical rod (1) and close to the opening of the accommodating groove (11), and the side surface where the T-shaped groove (18) is positioned is vertical to the side surface where the opening of the accommodating groove (11) is positioned; the positioning blocking piece (181) can block the transverse rod (2) from moving outwards the accommodating groove (11); a first reed (111) is installed in the accommodating groove (11); the distance between the first reed (111) and the opening of the accommodating groove (11) is smaller than the distance between the transverse rod (2) and the opening of the accommodating groove (11); the first reed (111) and the positioning baffle (181) are positioned at the same end of the vertical rod (1), and the first reed (111) and the rotating shaft (21) of the transverse rod (2) are respectively positioned at two ends of the vertical rod (1); silica gel columns (3) are uniformly arranged on the side surfaces of the vertical rods (1); the side surface where the silica gel column (3) is located is opposite to the side surface where the T-shaped groove (18) is located, and the silica gel column (3) is in contact with the blackboard surface; a sucker is arranged on the end face of the silica gel column (3) far away from the vertical rod (1); length scales are marked on the vertical rod (1) and the transverse rod (2).
2. A mathematical modeling teaching aid as claimed in claim 1, wherein: small suckers (31) are uniformly arranged on the inner surface of the sucker; a communicating hole (32) is formed in the sucker; the small suckers (31) are connected with each other through the communication holes (32).
3. A mathematical modeling teaching aid as claimed in claim 1, wherein: the vertical rod (1) is provided with a first mounting cavity (14); the opening of the first mounting cavity (14) and the silica gel column (3) are positioned on the same side; the number of the first mounting cavities (14) is two, and the first mounting cavities are respectively positioned at two ends of the vertical rod (1); a guide wheel (141) is arranged in the first mounting cavity (14); the guide wheels (141) are divided into two groups and are respectively positioned in the first mounting cavities (14); four guide wheels (141) are arranged in each group, and the guide wheels (141) are arranged in a rectangular shape; the length direction of a rectangle formed by the guide wheels (141) is vertical to the length direction of the vertical rod (1); a first fixing frame (142) and a second fixing frame (143) are mounted on a rotating shaft of the guide wheel (141), and the guide wheel (141) is located between the first fixing frame (142) and the second fixing frame (143); the distance between the first fixing frame (142) and the end face of the vertical rod (1) is smaller than the distance between the second fixing frame (143) and the end face of the vertical rod (1); the upper end of the second fixing frame (143) extends out of the surface of the vertical rod (1), and the second fixing frame (143) can move freely; the upper end of the second fixing frame (143) and the T-shaped groove (18) are positioned on the same side; a pressing rod (144) is arranged at the upper end of the second fixing frame (143); two ends of the pressing rod (144) are fixedly connected with the two second fixing frames (143) respectively; the vertical rod (1) is provided with a second mounting cavity; the mounting cavity II is located right below the vertical rod (1), and the pressing rod (144) can enter the mounting cavity II; a second reed (145) is mounted on the bottom surface of the second mounting cavity; the second reed (145) pushes the pressing rod (144) towards the outside of the installation cavity.
4. A mathematical modeling teaching aid as claimed in claim 3, wherein: a compression cavity (15) is formed in the vertical rod (1); the compression cavity (15) is positioned right below the pressing rod (144); a movable plate (151) is arranged in the compression cavity (15); a magnetic block (152) is arranged on the second fixing frame (143); the magnetic block (152) is magnetically connected with the movable plate (151); an installation groove (16) is formed in the vertical rod (1); the magnetic block (152) is positioned in the mounting groove (16), and the magnetic block (152) can move freely in the mounting groove (16); the space in the compression cavity (15) below the movable plate (151) is communicated to a communicating hole (32) on the silica gel column (3) through a pipeline.
5. A mathematical modeling teaching aid as claimed in claim 1, wherein: a third mounting cavity is formed in the rotating shaft (21); an air bag (211) is arranged in the third mounting cavity; a top block (213) is arranged in the third mounting cavity; the top block (213) is positioned above the air bag (211); clamping columns (212) are uniformly arranged in the side wall of the mounting cavity III, and the clamping columns (212) can move freely; the upper end of the top block (213) is conical, and the conical surface is contacted with one end of the clamping column (212) positioned in the third installation cavity; the clamping column (212) is connected with the top block (213) through a string; the other end of the clamping column (212) is tightly attached to the side surface of the sliding groove (13); the upper end of the third mounting cavity is provided with a push rod (214); the lower end of the push rod (214) is in contact with the upper surface of the top block (213), and the upper end of the push rod extends out of the vertical rod (1); the push rod (214) can move freely; the vertical rod (1) is provided with a guide groove (12); the push rod (214) is positioned in the guide groove (12), and the push rod (214) can freely move along the guide groove (12).
6. A mathematical modeling teaching aid as claimed in claim 1, wherein: a first groove (17) is formed in the middle of the vertical rod (1); the first groove (17) and the T-shaped groove (18) are positioned on the same side surface; the surface of the first groove (17) is sealed by a transparent panel; the edge of the first groove (17) is provided with angle scales; a mounting rod (171) is mounted at the central position in the first groove (17); a homogenizing rod (172) is rotatably arranged on the mounting rod (171); the mounting rod (171) is positioned in the middle of the homogenizing rod (172); a second groove (22) is formed in the middle of the transverse rod (2); the second groove (22) is positioned on the lateral surface, close to the first groove (17), of the transverse rod (2), and the lateral surface where the second groove (22) is positioned is parallel to the lateral surface where the first groove (17) is positioned; the surface of the second groove (22) is sealed by a transparent panel; the edge of the second groove (22) is provided with angle scales; a mounting rod (171) is mounted at the center position in the second groove (22); and a homogenizing rod (172) is rotatably arranged on the mounting rod (171).
7. A mathematical modeling teaching aid as claimed in claim 1, wherein: the vertical rods (1) and the transverse rods (2) are obtained by bonding multiple layers of plastic sheets; thin steel sheets are arranged between the vertical rods (1) and the transverse rods (2).
CN202011036226.9A 2020-09-27 2020-09-27 Mathematical modeling teaching aid Active CN112172387B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011036226.9A CN112172387B (en) 2020-09-27 2020-09-27 Mathematical modeling teaching aid

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011036226.9A CN112172387B (en) 2020-09-27 2020-09-27 Mathematical modeling teaching aid

Publications (2)

Publication Number Publication Date
CN112172387A CN112172387A (en) 2021-01-05
CN112172387B true CN112172387B (en) 2022-02-22

Family

ID=73944639

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011036226.9A Active CN112172387B (en) 2020-09-27 2020-09-27 Mathematical modeling teaching aid

Country Status (1)

Country Link
CN (1) CN112172387B (en)

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9925822B2 (en) * 2015-05-27 2018-03-27 Yung-Peng Chiu Pen track
CN206653811U (en) * 2016-11-15 2017-11-21 河套学院 A kind of mathematical modeling drawing tools
CN106926617B (en) * 2017-04-21 2018-06-29 郑州航空工业管理学院 A kind of mathematical education drawing board
CN208584986U (en) * 2018-03-16 2019-03-08 刘昕宇 A kind of mathematics displaying device
CN208789355U (en) * 2018-05-22 2019-04-26 李明素 One kind is for showing elliptical teaching apparatus for mathematics
CN108859518B (en) * 2018-06-15 2020-11-06 闫志忠 Drawing auxiliary mechanism for mathematical education
CN108470496A (en) * 2018-06-29 2018-08-31 亳州学院 A kind of mathematical modeling teaching aid
CN210132923U (en) * 2019-03-28 2020-03-10 李佳桐 Mathematics teaching is with supplementary drawing device
CN209813548U (en) * 2019-04-04 2019-12-20 吉安职业技术学院 Drawing device for mathematics teaching
CN110654146A (en) * 2019-09-29 2020-01-07 黑龙江科技大学 A multi-functional teaching aid for mathematical education usefulness
CN211138825U (en) * 2019-10-17 2020-07-31 河南应用技术职业学院 Drawing tool for mathematics teaching
CN110560796A (en) * 2019-10-23 2019-12-13 南京工业职业技术学院 Movable variable parameter involute drawing and cutting multipurpose machine
CN111516416A (en) * 2020-04-21 2020-08-11 安徽理工大学 Drawing rule for applied mathematics teaching

Also Published As

Publication number Publication date
CN112172387A (en) 2021-01-05

Similar Documents

Publication Publication Date Title
CN207089749U (en) Film sticking machine
CN112172387B (en) Mathematical modeling teaching aid
CN214688765U (en) Ellipse drawing device for mathematical education
CN111248633A (en) Adjustable mathematical education plotter
CN220949461U (en) Storage rack convenient for taking glass raw sheets
CN112693252B (en) Mathematics teaching is with supplementary teaching device
CN206058630U (en) A kind of mathematics explanation draws plate with secondary graphics
CN213691059U (en) Teaching aid is used in university's mathematics limit teaching
CN113034990A (en) A record device in class a little for english teaching
CN219618804U (en) Staff scriber
CN220808978U (en) Curve drawing device
CN215003312U (en) Three-dimensional coordinatometer for mathematics learning
CN211827692U (en) Art design course is with teaching auxiliary system
CN221137347U (en) Drawing book scriber
CN220390828U (en) Drawing device
CN221116185U (en) Transport transmission mechanism suitable for printing machine
CN221211389U (en) Adsorption clamping device suitable for curved liquid crystal display
CN210454239U (en) Mathematical thinking explanation note explanation board
CN211349576U (en) English vocabulary teaching auxiliary device
CN217880600U (en) Seal cutting impression wheel teaching aid
CN219076801U (en) High-definition transfer powder machine for powder coating production
CN203134204U (en) Suspension type probability theory teaching mold
CN210759962U (en) Novel meshing curve gear generating instrument capable of being printed
CN213441812U (en) Teaching is with oval instrument of drawing
CN219564598U (en) Oval drawing device of middle-position teaching

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant