CN111959163A

CN111959163A - Compasses equipment for student's mechanical drawing

Info

Publication number: CN111959163A
Application number: CN202010796780.0A
Authority: CN
Inventors: 李彩琴
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-08-10
Filing date: 2020-08-10
Publication date: 2020-11-20

Abstract

The invention relates to the technical field of mechanical drawing, and discloses compasses for mechanical drawing of students, which comprise a left support rod, wherein a right support rod is arranged on the right side of the left support rod, the top end of the left support rod and the top end of the right support rod are movably sleeved through a linkage handle, a precise regulating and controlling bolt is arranged on the front side of the linkage handle, and the back side of the precise regulating and controlling bolt sequentially penetrates through the linkage handle, the left support rod and the right support rod and extends to the outer side of the back side of the linkage handle. This compasses equipment for student's mechanical drawing, through left branch pole, the perpendicular heart device, cooperation between centre of a circle mark device and the spacing groove, utilize the inside fixed point activity of spherical cover and spacing groove to cup joint, perpendicular pole and the perpendicular fixed connection of centre of a circle mark device, when left branch pole is in the slope, keep the perpendicular heart device to be in the vertical state with the drawing paper all the time, the needle end through centripetal lines replacement current compasses marks the centre of a circle, play the effect of protection to the drawing paper, the accuracy of drawing compasses size has been improved simultaneously.

Description

Compasses equipment for student's mechanical drawing

Technical Field

The invention relates to the technical field of mechanical drawing, in particular to compasses for mechanical drawing of students.

Background

In mathematics and drawing, compasses are used for drawing circles or strings and are usually used for drawing by ruler compasses. And the arc length of one end with the pencil which rotates for a circle or corresponding angle is taken as a circle or arc which is correspondingly drawn.

In the process of drawing, the existing compasses need to separate one end of the compasses with a needle from one end of the compasses with a pencil, the distance between the two end points is the radius of the drawn figure, when the radius of the drawn figure is larger, a certain inclination angle is formed between the end with the needle and the end with the pencil and the drawn figure, the end with the needle of the compasses needs to be fixed with paper in the drawing process, at the moment, the drawing process is carried out by pressing the compasses for rotation, the force applied along the end with the needle can be decomposed into a component force along the paper (namely a horizontal plane) and a component force vertical to the paper, the component force along the paper can easily force the needle end to move along the direction of the component force, the needle end can easily cut the drawn paper, the operation is inconvenient for users, and the tip can easily scratch the users in the use process and is inconvenient to store and carry, when the force of a user pressing one end of the compass with the needle is too strong, the needle end is easy to sink into the drawing paper, so that the drawing is damaged (namely a circle center groove is formed), and the needle end and one end of the pencil are not on the same horizontal plane, so that the radius of a circle or an arc actually drawn is smaller than that of a set circle or arc, and the accuracy of the graph drawn by the compass is reduced; and the pencil is in the tilt state, and in the drawing process, the one side atress that the pencil is close to the centre of a circle is greater than the atress of keeping away from centre of a circle one side to easily cause the pencil to be easy to break in drawing circle or circular arc process, then reduce the utilization ratio of pencil, easily influence user's drawing efficiency and attitude simultaneously, for this reason we provide a compasses equipment for student's mechanical drawing.

Disclosure of Invention

The invention provides compasses equipment for mechanical drawing of students, which has the functions of protecting drawing paper, improving the accuracy of drawing size of the compasses, improving the utilization rate of a pencil, ensuring the drawing efficiency of a user and having good mind state, and solves the problems that in the drawing process of the existing compasses, one end of the compasses with a needle is required to be separated from one end with the pencil, the distance between two end points is the radius of the drawn figure, when the radius of the drawn figure is larger, both the end with the needle and the end with the pencil have a certain inclination angle with the drawing paper, the end with the needle of the compasses is required to be fixed with the paper in the drawing process, the drawing process can be decomposed into a component force along the paper and a component force vertical to the paper along the end with the needle, the needle end is easy to be forced to move along the direction of the component force along the paper, the needle end is easy to scratch the drawing paper, the operation is inconvenient for a user, the tip end is easy to scratch the user in the using process, the needle end is inconvenient to store and carry, the needle end is easy to damage, when the force for pressing the end of the compasses with the needle is too strong, the needle end is easy to sink into the drawing paper, the drawing is damaged, the needle end and one end of a pencil are not on the same horizontal plane, the radius of a circle or an arc which is actually drawn is smaller than the radius of a set circle or arc, and the accuracy of the graph drawn by the compasses is reduced; and the pencil is in the tilt state, and in the drawing process, the one side atress that the pencil is close to the centre of a circle is greater than the atress of keeping away from centre of a circle one side to easily cause the pencil to easily break in drawing circle or circular arc process, then reduce the utilization ratio of pencil, easily influence the problem of user's drawing efficiency and attitude simultaneously.

In order to achieve the above purpose, the invention provides the following technical scheme to realize: the compasses for mechanical drawing of students comprise a left support rod, wherein a right support rod is arranged on the right side of the left support rod, the top end of the left support rod and the top end of the right support rod are movably sleeved through a linkage handle, a precise regulation and control bolt is arranged on the front side of the linkage handle, the back side of the precise regulation and control bolt sequentially penetrates through the linkage handle, the left support rod and the right support rod and extends to the outer side of the back side of the linkage handle, the precise regulation and control bolt is in threaded sleeve connection with the linkage handle, the outer surface of the linkage handle is movably connected with the inner parts of the top ends of the left support rod and the right support rod, a transverse groove is opened and closed at the bottom of the right support rod, an anti-tilting device is arranged inside the transverse groove and comprises a sliding ball, a limit sleeve is fixedly sleeved on the outer side of the sliding ball, the outer surface of the limit sleeve is movably sleeved with the bottom of an inner cavity, the top of automatic plumb bar runs through the stop collar and extends to the inside of transverse groove, the bottom of automatic plumb bar runs through sliding ball and transverse groove and extends to the outside of right branch pole, the equal swing joint of the inside of automatic plumb bar and stop collar and the inner chamber of transverse groove, the inside joint of automatic plumb bar has plumbous, the interval between the bottom of plumbous and the sliding ball centre of sphere point equals to the interval between the sliding ball centre of sphere point on the top of automatic plumbous and the sliding ball centre of sphere point.

Optionally, a limiting plate is movably sleeved at the bottom end of the automatic lead rod, a fastening bolt is arranged on the front face of the limiting plate, the top end of the fastening bolt penetrates through the limiting plate and extends to the bottom of the plumbous core, the outer surface of the fastening bolt is sleeved with the internal thread of the limiting plate, the top end of the fastening bolt is in contact with the bottom of the plumbous core, and the bottom end of the limiting plate and the bottom end of the plumbous core are located on the same horizontal straight line.

Optionally, the spacing groove has been seted up to the bottom of left branch pole, the inside of spacing groove is provided with the heart device of hanging down, the bottom fixedly connected with centre of a circle marker equipment of the heart device of hanging down, the heart device of hanging down is including the heart ball of hanging down, the spherical cover has been cup jointed in the outside activity of the heart ball of hanging down, the surface of spherical cover and the inner chamber fixed connection of spacing groove, the arc wall has been seted up to the lower surface of spherical cover, and the arc wall is along the lower surface evenly distributed of spherical cover, the arc center angle of spherical cover arc wall is 220 degrees, and the angular bisector of arc center angle is located under the heart ball center of hanging down.

Optionally, the bottom fixedly connected with vertical rod of heart ball hangs down, the bottom of vertical rod runs through spherical cover arc wall and transverse groove in proper order and extends to the below of transverse groove, the surface of vertical rod and the equal activity of the inner chamber of spherical cover arc wall and transverse groove cup joint, the shape size homogeneous phase of heart ball and sliding ball hangs down, and the centre of sphere of heart ball and sliding ball lies in same horizontal straight line.

Optionally, the circle center marking device comprises a transparent circular table body, the top end of the transparent circular table body is fixedly connected with the bottom of the vertical rod, the bottom of the transparent circular table body is fixedly connected with a transparent circular plate, the bottom of the transparent circular plate is provided with an identification mechanism, the identification mechanism comprises a centripetal line, the centripetal line is located under the central point of the transparent circular plate, the bottom of the centripetal line is fixedly connected with the bottom of the transparent circular plate, centripetal lines are arranged on the outer side of the centripetal line, the number of the centripetal lines is four, the distances between every two adjacent centripetal lines are equal, the side surfaces of the centripetal lines are fixedly connected with the bottom of the transparent circular plate, the bottoms of the centripetal line, the transparent circular plate and the four centripetal lines are located on the same horizontal plane, and the centripetal line is located under the spherical center point of the centripetal ball, the vertical distance between the bottom end of the centripetal line and the center point of the vertical center ball is equal to the vertical distance between the bottom end of the vertical center lead and the center point of the sliding ball.

The invention provides compasses equipment for mechanical drawing of students, which has the following beneficial effects:

1. the compasses equipment for mechanical drawing of students utilizes the matching between the left support rod, the vertical rod, the circle center marking device and the limiting groove to movably sleeve the inner fixed point of the limiting groove by utilizing the spherical sleeve, the vertical rod is vertically and fixedly connected with the circle center marking device, when the left support rod is inclined, the vertical rod is always kept to be in a vertical state with the drawing paper, simultaneously, the transparent circular plate is attached to the surface of the drawing paper, the contact area between the circle center point and the drawing paper is increased, simultaneously, the spherical shape of the vertical ball is movably connected with the circle center marking device by combining the left support rod, the centripetal line replaces the needle end of the existing compasses to mark the circle center, the needle end is effectively prevented from scratching the drawing paper, the operation is inconvenient for a user, the needle end and one end of a pencil are not on the same horizontal plane, and the sharp end easily causes scratch phenomenon to the user in the using process, the compass has the advantages that the compass protects the drawing paper, and meanwhile, the accuracy of the drawing size of the compass is improved.

2. The compasses equipment for mechanical drawing of students utilizes the mode that the limiting sleeve is movably sleeved with the inner cavity of the transverse groove through the matching among the transverse groove, the anti-tilting device and the limiting plate, when the right supporting rod is inclined, the anti-inclination device is always kept in a vertical state with the drawing paper, meanwhile, the bottom of the limiting plate and the plumb are positioned in the same horizontal plane, so that the connection line between the front end and the rear end of the bottom surface of the limiting plate and the plumb in a pairwise adjacent manner is ensured to form a triangle, the plumb is always positioned under the center point of the sliding ball, namely on the circumference of the drawn circle, the pencil is effectively prevented from being in an inclined state, the force applied to one side of the pencil close to the circle center is larger than the force applied to one side far away from the circle center in the drawing process, therefore, the phenomenon that the pencil is easy to break in the process of drawing a circle or a circular arc is caused, the utilization rate of the pencil is improved, and meanwhile, the drawing efficiency and the good mood of a user are guaranteed.

Drawings

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

FIG. 2 is a schematic view of the anti-tilt device of the present invention in a drawing state;

FIG. 3 is a schematic view of a detailed structure of the vertical center device of the present invention;

FIG. 4 is a side schematic view of a transverse slot of the present invention;

FIG. 5 is a schematic top half-sectional view of a transparent circular plate according to the present invention;

FIG. 6 is a schematic top view of a plumb line according to the present invention;

FIG. 7 is a schematic bottom view of the stop collar of the present invention;

FIG. 8 is an enlarged schematic view of the plumb sphere of FIG. 2 according to the present invention;

fig. 9 is an enlarged view of the sliding ball of fig. 2 according to the present invention.

In the figure: 1. a left strut; 2. a right strut; 3. a linkage handle; 4. a plumbing device; 41. a plumb sphere; 42. a vertical rod; 43. a spherical sleeve; 5. fastening a bolt; 6. a circle center marking device; 61. a transparent cone; 62. an identification mechanism; 621. line of plumb bob; 622. a centripetal line; 63. a transparent circular plate; 7. a limiting plate; 8. a transverse slot; 9. an anti-tilt device; 91. a sliding ball; 92. automatic lead rod; 93. a limiting sleeve; 94. plumb line; 10. a limiting groove; 11. the bolt is regulated and controlled precisely.

Detailed Description

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

Referring to fig. 1-9, a pair of compasses for mechanical drawing of students comprises a left support rod 1, a right support rod 2 is arranged on the right side of the left support rod 1, the top end of the left support rod 1 and the top end of the right support rod 2 are movably sleeved through a linkage handle 3, a precise control bolt 11 is arranged on the front side of the linkage handle 3, the back side of the precise control bolt 11 sequentially penetrates through the linkage handle 3, the left support rod 1 and the right support rod 2 and extends to the outer side of the back side of the linkage handle 3, the precise control bolt 11 is in threaded sleeve connection with the linkage handle 3, the outer surface of the linkage handle 3 is movably connected with the inner parts of the top ends of the left support rod 1 and the right support rod 2, a transverse groove 8 is opened and closed at the bottom of the right support rod 2, an anti-tilting device 9 is arranged inside the transverse groove 8, the anti-tilting device 9 comprises a sliding ball 91, a limit sleeve 93, the surface of stop collar 93 cup joints with the bottom activity of the 8 inner chambers of transverse groove, the inside fixedly connected with of sliding ball 91 is from plumb rod 92, the inside that stop collar 93 and extended to transverse groove 8 is run through on the top of from plumb rod 92, the bottom of from plumb rod 92 runs through sliding ball 91 and transverse groove 8 and extends to the outside of right branch pole 2, the inside of from plumb rod 92 and stop collar 93 and the equal swing joint of inner chamber of transverse groove 8, the inside joint of from plumb rod 92 has plumb-bob 94, the interval between the bottom of plumb-bob 94 and the sliding ball 91 centre of sphere point equals with the interval between the top of from plumb rod 92 to sliding ball 91 centre of sphere point.

Wherein, the bottom end of the automatic lead rod 92 is movably sleeved with a limiting plate 7, the front surface of the limiting plate 7 is provided with a fastening bolt 5, the top end of the fastening bolt 5 penetrates through the limiting plate 7 and extends to the bottom of the plumb line 94, the outer surface of the fastening bolt 5 is sleeved with the internal thread of the limiting plate 7, the top end of the fastening bolt 5 is contacted with the bottom of the plumb line 94, the bottom end of the limiting plate 7 and the bottom end of the plumb line 94 are positioned on the same horizontal straight line, by utilizing the mode that the limiting sleeve 93 is movably sleeved with the inner cavity of the transverse groove 8, when the right support rod 2 is inclined, the anti-inclination device 9 is always in a vertical state with the drawing paper, and simultaneously, the bottom of the limiting plate 7 and the plumb line 94 are positioned on the same horizontal plane, so as to ensure that the connecting lines between the front and back two adjacent ends of the bottom surface of the, then, the plumb bob 94 is kept to be always positioned under the center point of the sliding ball 91, namely on the circumference of the drawn circle, the pencil is effectively prevented from being in an inclined state, and in the drawing process, the stress on one side of the pencil close to the center of the circle is larger than the stress on one side of the pencil far away from the center of the circle, so that the phenomenon that the pencil is easy to break in the process of drawing the circle or the circular arc is caused, the utilization rate of the pencil is improved, and meanwhile, the drawing efficiency and the good mood of a user are guaranteed.

Wherein, the bottom of the left supporting rod 1 is provided with a limiting groove 10, a vertical center device 4 is arranged inside the limiting groove 10, the bottom of the vertical center device 4 is fixedly connected with a circle center marking device 6, the vertical center device 4 comprises a vertical center ball 41, the outer side of the vertical center ball 41 is movably sleeved with a spherical sleeve 43, the outer surface of the spherical sleeve 43 is fixedly connected with the inner cavity of the limit groove 10, the lower surface of the spherical sleeve 43 is provided with an arc-shaped groove which is uniformly distributed along the lower surface of the spherical sleeve 43, the arc center angle of the arc-shaped groove of the spherical sleeve 43 is 220 degrees, and the angular bisector of the arc center angle is positioned under the sphere center of the vertical center ball 41, the spherical sleeve 43 is movably sleeved with the inner fixed point of the limit groove 10, the vertical rod 42 is vertically and fixedly connected with the circle center marking device 6, when the left support rod 1 is inclined, the vertical center device 4 is always kept in a vertical state with the drawing paper.

The bottom end of the vertical rod 42 sequentially penetrates through the arc-shaped groove of the spherical sleeve 43 and the transverse groove 8 and extends to the lower part of the transverse groove 8, the outer surface of the vertical rod 42 is movably sleeved with the inner cavities of the arc-shaped groove of the spherical sleeve 43 and the transverse groove 8, the vertical ball 41 and the sliding ball 91 are identical in shape and size, the centers of the vertical ball 41 and the sliding ball 91 are located on the same horizontal straight line, and then the distance between the centers of the vertical ball 41 and the sliding ball 91 is the radius of the drawn graph.

Wherein, centre of a circle mark device 6 is including transparent round platform body 61, the top of transparent round platform body 61 and the bottom fixed connection of vertical rod 42, the bottom fixed connection of transparent round platform body 61 has transparent plectane 63, the bottom of transparent plectane 63 is provided with identification mechanism 62, identification mechanism 62 is including the line 621 of centripetal, the line 621 of centripetal is located under transparent plectane 63 central point, the line 621 of centripetal is fixed connection with the bottom of transparent plectane 63, the outside of the line 621 of centripetal is provided with centripetal line 622, the quantity of centripetal line 622 is four, four the interval between two liang of adjacent lines 622 of centripetal is equal, four the side of centripetal line 622 and the bottom fixed connection of transparent plectane 63, the bottom of the line 621 of centripetal, transparent plectane 63 and four centripetal lines 622 of centripetal is on same horizontal plane, the centripetal line 622 is positioned right below the center point of the vertical center ball 41, the vertical distance between the bottom end of the centripetal line 622 and the center point of the vertical center ball 41 is equal to the vertical distance between the bottom end of the vertical center lead 94 and the center point of the sliding ball 91, namely, the bottom end of the centripetal line 622 and the bottom end of the vertical center lead 94 are positioned on the same horizontal straight line, and simultaneously, the transparent circular plate 63 is attached to the surface of the drawing paper to increase the contact area between the center point and the drawing paper, and simultaneously, the spherical shape of the vertical center ball 41 and the circle center marking device 6 are movably connected by combining the left support rod 1, the centripetal line 622 replaces the needle end of the existing compasses to mark the circle center, so that the phenomena that the needle end cuts the drawing paper, the operation of a user is inconvenient, the needle end and one end of a pencil are not on the same horizontal plane, and the sharp end easily scratches the user in the using process are avoided, the compass has the advantages that the compass protects the drawing paper, and meanwhile, the accuracy of the drawing size of the compass is improved.

Firstly, a worker places paper to be drawn on a horizontal desktop, then a fixed point (namely the center of a circle/the arc center of a circular arc) of a drawing shape is determined, then a left support rod 1 and a right support rod 2 are separated towards one side of the principle, the radius of the drawing figure is determined, namely the distance between the center of the sliding ball 91 and the center of the plumb-center ball 41, then a transparent circular plate 63 is placed in the circle center area, a centripetal line 622 is made to coincide with the position of the circle center, namely one top end of the radius, at the moment, a plumb lead 94 at the bottom of an automatic plumb rod 92 is placed at the other end of the corresponding radius, the bottom of the transparent circular plate 63 and the bottom end of the plumb lead 94 are both positioned on the same plane of the same drawing paper, and then the user draws the corresponding figure by rotating the linkage handle 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 compasses equipment for student's mechanical drawing, includes left branch pole (1), its characterized in that: the right side of the left support rod (1) is provided with a right support rod (2), the top end of the left support rod (1) and the top end of the right support rod (2) are movably sleeved through a linkage handle (3), the front side of the linkage handle (3) is provided with a precision regulation and control bolt (11), the back side of the precision regulation and control bolt (11) sequentially penetrates through the linkage handle (3), the left support rod (1) and the right support rod (2) and extends to the outer side of the back side of the linkage handle (3), the precision regulation and control bolt (11) is in threaded sleeve connection with the linkage handle (3), the outer surface of the linkage handle (3) is movably connected with the inner parts of the top ends of the left support rod (1) and the right support rod (2), the bottom of the right support rod (2) is opened and closed with a transverse groove (8), an anti-tilting device (9) is arranged inside the transverse groove (8), and the anti-tilting device (9) comprises a sliding ball, the outer side of the sliding ball (91) is fixedly sleeved with a limit sleeve (93), the outer surface of the limit sleeve (93) is movably sleeved with the bottom of the inner cavity of the transverse groove (8), an automatic lead rod (92) is fixedly connected inside the sliding ball (91), the top end of the automatic lead rod (92) penetrates through the limiting sleeve (93) and extends into the transverse groove (8), the bottom end of the automatic lead rod (92) penetrates through the sliding ball (91) and the transverse groove (8) and extends to the outer side of the right support rod (2), the automatic lead rod (92) is movably connected with the inner part of the limiting sleeve (93) and the inner cavity of the transverse groove (8), the inside joint of automatic plumb bar (92) has orthocenter plumb (94), the equal interval between the top of automatic plumb bar (92) and the ball center point of sliding ball (91) is equal with the interval between the ball center point of sliding ball (91) and the bottom of orthocenter plumb (94).

2. The compasses apparatus for student's mechanical drawing according to claim 1, characterized in that: limiting plate (7) has been cup jointed in the bottom activity of automatic plumbous pole (92), the front of limiting plate (7) is provided with fastening bolt (5), limiting plate (7) and the bottom that extends to plumbous heart (94) are run through on the top of fastening bolt (5), the surface of fastening bolt (5) cup joints with the internal thread of limiting plate (7), the top of fastening bolt (5) contacts with the bottom of plumbous heart (94), the bottom of limiting plate (7) and the bottom of plumbous heart (94) are in on the same horizontal straight line.

3. The compasses apparatus for student's mechanical drawing according to claim 1, characterized in that: spacing groove (10) have been seted up to the bottom of left branch pole (1), the inside of spacing groove (10) is provided with vertical core device (4), the bottom fixedly connected with centre of a circle marker device (6) of vertical core device (4), vertical core device (4) is including vertical core ball (41), spherical cover (43) have been cup jointed in the outside activity of vertical core ball (41), the surface of spherical cover (43) and the inner chamber fixed connection of spacing groove (10), the arc wall has been seted up to the lower surface of spherical cover (43), and the arc wall is along the lower surface evenly distributed of spherical cover (43), the arc center angle of spherical cover (43) arc wall is 220 degrees, and the angular bisector of arc center angle is located vertical core ball (41) centre of sphere under.

4. The compasses apparatus for student's mechanical drawing according to claim 3, characterized in that: the bottom fixedly connected with vertical rod (42) of heart ball (41) hangs down, the bottom of vertical rod (42) runs through spherical cover (43) arc wall and transverse groove (8) in proper order and extends to the below of transverse groove (8), the surface of vertical rod (42) and the equal activity of inner chamber of spherical cover (43) arc wall and transverse groove (8) cup joint, the shape size homogeneous phase of heart ball (41) and sliding ball (91) hangs down, and the centre of sphere of heart ball (41) and sliding ball (91) that just hangs down is located same horizontal straight line.

5. The compasses apparatus for student's mechanical drawing according to claim 4, characterized in that: circle center marking device (6) is including transparent round platform body (61), the top of transparent round platform body (61) and the bottom fixed connection of vertical pole (42), the bottom fixedly connected with transparent plectane (63) of transparent round platform body (61), the bottom of transparent plectane (63) is provided with identification mechanism (62), identification mechanism (62) are including the line (621) of falling heart, the line (621) of falling heart is located transparent plectane (63) under the central point, the bottom fixed connection of the line (621) of falling heart and transparent plectane (63), the outside of the line (621) of falling heart is provided with centripetal line (622), the quantity of centripetal line (622) is four, four the interval between two liang of centripetal line (622) is equal, four the side of centripetal line (622) and the bottom fixed connection of transparent plectane (63), the bottom of the vertical center line (621), the bottom of the transparent circular plate (63) and the bottom of the four centripetal lines (622) are located on the same horizontal plane, the centripetal lines (622) are located right below the center points of the vertical center ball (41), and the vertical distance between the bottom end of the centripetal lines (622) and the center points of the vertical center ball (41) is equal to the vertical distance between the bottom end of the vertical center lead (94) and the center points of the sliding ball (91).