KR20130049533A - Auto blackboard eraser - Google Patents

Abstract

PURPOSE: An automatic blackboard eraser is provided to use two eraser pads which are capable of performing a reciprocating motion simultaneously with an eccentric rotary motion, thereby wiping a blackboard clearly; and to use one motor, thereby saving electricity. CONSTITUTION: An automatic blackboard eraser comprises a body unit(100), an upper wheel unit(200), an upper part eraser unit(300), a crank unit(400), a motor, a first rocker(500), a lower wheel unit(600), a lower part eraser unit, a second rocker(800). The first rocker has one end which is connected to the upper wheel unit and the other end which is connected to the crank unit. The lower wheel unit is formed in a guide groove on the lower part, and placed on the position symmetrical with the upper wheel unit across the crank unit. The lower part eraser unit is connected to the lower wheel unit, and equipped with a second eraser pad which is surface-contacted with the blackboard. The rocker has one end which is connected to the lower wheel unit, and the other end which is connected to the crank unit.

Description

Auto blackboard eraser {Auto blackboard eraser}

The present invention relates to the technical field of the blackboard eraser, and more particularly, to an automatic blackboard eraser capable of a reciprocating motion and an eccentric rotation motion.

In general, a blackboard eraser is a tool used to erase chalk powder written on a blackboard or ink written on a white board, and a manual method of removing chalk powder or ink by a user directly using an eraser pad is widely used. However, such a manual type has a problem that the blackboard is wiped out according to the force applied by the user and a problem that the user takes a lot of power.

Accordingly, a number of automatic blackboard erasers have been proposed, such as Korean Patent Application Publication No. 1999-0085167, which can clean a blackboard by a simple operation of a user. The conventional automatic blackboard eraser is open to the side in contact with the blackboard, the case is mounted vertically to the blackboard, the eraser pad rotatably installed in the inside of the case, the drive unit for rotating the eraser pad, the eraser pad It consists of a conveyance part which moves to a horizontal direction.

However, the conventional automatic blackboard eraser has a problem that the blackboard surface corresponding to the excitation portion is not properly wiped when a portion of the eraser pad does not come into contact with the blackboard surface, and the problem that is not properly wiped out of the blackboard surface is subsequently stained and accordingly There was a problem that the life of the blackboard could be shortened.

In addition, since the eraser pad reciprocates only the surface of the board, it is made of a structure that can not perform the translation movement, and also contains a problem that less chalk powder or ink is removed than when the user manually wipes the board.

Korean Patent Publication No. 1999-0085167

The present invention has been made to solve the above problems, an object of the present invention by reciprocating and eccentric rotation of the two eraser pads with a single motor, an automatic blackboard that can more effectively wipe the blackboard while reducing the manufacturing cost Is to provide an eraser.

Automatic blackboard eraser of the present invention for solving the above problems, the body portion having an upper guide groove formed in the upper portion of the blackboard and the lower guide groove formed in the lower portion of the blackboard; An upper wheel part formed in the upper guide groove; An upper eraser portion connected to the upper wheel portion and having a first eraser pad in surface contact with the blackboard; A crank part formed at the center of the blackboard; A motor coupled to a center of the crank part and transmitting power to the crank part; A first locker having one end connected to the upper wheel part and the other end connected to the crank part; A lower wheel part formed in the lower guide groove and formed at a position symmetrical with the upper wheel part based on the crank part; A lower eraser portion connected to the lower wheel portion and provided with a second eraser pad in surface contact with the blackboard; And a second locker having one end connected to the lower wheel part and the other end connected to the crank part.

In the automatic blackboard eraser of the present invention, the upper wheel part may include a first upper wheel which is in surface contact with an inner lower surface of the upper guide groove and whose central axis is connected to the first locker; A second upper wheel formed to be in surface contact with the upper surface of the upper guide groove and the first upper wheel; . ≪ / RTI >

In the automatic blackboard eraser of the present invention, the circumferential ratio of the first upper wheel and the second upper wheel is preferably 3: 1, but is not limited thereto.

In the automatic blackboard eraser of the present invention, the upper eraser may include an upper link having one end eccentrically coupled with the second upper wheel and the other end coupled with the first eraser pad.

In the automatic blackboard eraser of the present invention, the body portion may further include an upper wheel guide bar formed between the first upper wheel and the second upper wheel.

In the automatic blackboard eraser of the present invention, the lower wheel part may include: a first lower wheel in surface contact with an inner upper surface of the lower guide groove and having a central axis connected to the second rocker; A second lower wheel formed to be in surface contact with the inner bottom surface of the lower guide groove and the first lower wheel; . ≪ / RTI >

In the automatic blackboard eraser of the present invention, the circumferential ratio of the first lower wheel and the second lower wheel is preferably 3: 1, but is not limited thereto.

In the automatic blackboard eraser of the present invention, the lower eraser may include a lower link having one end eccentrically coupled with the second lower wheel and the other end coupled with the second eraser pad.

In the automatic blackboard eraser of the present invention, the body portion may further include a lower wheel guide bar formed between the first lower wheel and the second lower wheel.

In the automatic blackboard eraser of the present invention, the crank portion, the crank body; And a central axis formed at the center of the crank body and coupled with the driving shaft of the motor.

In the automatic blackboard eraser of the present invention, the crank body includes a first crank body and a second crank body spaced apart from the first crank body, and the central axis includes the center of the first crank body and the second crank. It may be made of a structure for connecting the center of the body.

In the automatic blackboard eraser of the present invention, any one of the first crank body and the second crank body is eccentrically coupled to the other end of the first locker, and the other of the first crank body and the second crank body is It may be made of a structure that is eccentrically coupled with the other end of the second locker.

In the above-described automatic blackboard eraser of the present invention, the motor may be made of a DC motor.

In the automatic blackboard eraser of the present invention, the drive shaft of the motor may be coupled to the crankshaft center and the shaft via a bevel gear.

According to the present invention, it is possible to achieve the effect of realizing the automatic blackboard eraser with a simple structure that can move two eraser pads at the same time using a single motor and to reduce the manufacturing cost by implementing the simple structure.

In addition, according to the present invention, since the reciprocating motion and the eccentric rotation of the eraser pad are possible at the same time, there is an effect that can clean the blackboard cleaning task compared to the conventional blackboard eraser.

In addition, the automatic blackboard eraser of the present invention can be driven with one degree of freedom, and also has a power saving effect by using a single motor.

1 is a front view showing the automatic blackboard eraser structure according to an embodiment of the present invention.
Figure 2 is a side cross-sectional view of the automatic blackboard eraser shown in Figure 1 viewed from the side.
Figure 3 illustrates an embodiment of the upper wheel portion and the upper eraser portion according to the present invention.
Figure 4 shows an embodiment of the rear structure of the upper wheel portion according to the present invention.
Figure 5 shows a modified embodiment of the body portion according to the present invention.
Figure 6 shows the results of simulating the movement trajectory of the eraser pad according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it is to be understood that the contents described herein are only exemplary embodiments of the present invention, and that various equivalents and modifications may be substituted for them at the time of the present application. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the subject matter of the present invention. The following terms are terms defined in consideration of functions in the present invention, and the meaning of each term should be interpreted based on the contents throughout the present specification. The same reference numerals are used for parts having similar functions and functions throughout the drawings.

1 is a front view showing the automatic blackboard eraser structure according to an embodiment of the present invention.

Referring to FIG. 1, the automatic blackboard eraser 10 according to the present invention includes an upper guide groove 111 formed at an upper portion of the blackboard B and a lower guide groove 131 formed at a lower portion of the blackboard B. FIG. An upper eraser portion 310 having a body portion 100, an upper wheel portion 200 formed in the upper guide groove 111, a first eraser pad 310 in surface contact with the blackboard B, and an upper eraser portion connected to the upper wheel portion 200 ( 300, the crank portion 400 formed in the center of the blackboard (B) and rotatable with the center (P) of the crank portion 400 is transferred to the crank portion 400 by the shaft is transferred to the crank portion 400 Rotor) is formed in the first rocker 500, the lower guide groove 131 for connecting the motor (not shown), the upper wheel unit 200 and the crank unit 400, the upper part based on the crank unit 400 A lower wheel part 600 formed at a position symmetrical with the wheel part 200, a second eraser pad 710 in surface contact with the blackboard B, and a lower eraser part 700 connected to the lower wheel part 600; The it may be formed including the second rocker (800) to connect the unit hwilbu 700 and the crank 400. The

The blackboard (B) to which the present invention is applied may be a blackboard in the form of chalk or a blackboard in the form of a whiteboard using a marker, but the scope of the present invention is not limited thereto, and in addition, all forms of writing are possible. The automatic blackboard eraser 10 of the present invention can be applied to a blackboard.

The body portion 100 serves to support the components of the present invention, and more specifically, serves to support the upper wheel portion 200 and the lower wheel portion 600. In particular, the body portion 100 also includes an upper guide portion 111 and a lower guide portion 131 to guide the movement path of the upper wheel portion 200 and the lower wheel portion 600. The body portion 100 of the present invention may be formed in a separate form, as shown in Figure 1, that is, the upper body 110 formed on the upper portion of the blackboard (B) and the lower body 130 formed on the lower portion of the blackboard (B). However, the present invention is not limited thereto, and the upper body 110 and the lower body 130 may be integrally formed.

The upper wheel part 200 is connected to the crank part 400 by the first locker 500, and receives the rotational force of the crank part 400 that is rotated by the driving force of the motor to erase the first eraser part 300. The pad 310 is a part for reciprocating and eccentric rotation. The upper wheel part 200 of the present invention includes a first upper wheel 210 and a second upper wheel 230. The first upper wheel 210 is formed in surface contact with the inner lower end of the upper guide groove 111, and one end of the first rocker 500 is coupled to the central axis of the first upper wheel 210. Accordingly, when the crank part 400 rotates, the first upper wheel 210 is rotated by receiving a rotational force through the first rocker 500, and as a result, the central axis of the first upper wheel 210 is the upper guide. A straight reciprocating motion is performed along the groove 111.

The second upper wheel 230 is formed on the upper side of the first upper wheel 210 and is in surface contact with the inner upper surface of the upper guide groove 111 and the first upper wheel 210. Accordingly, when the first upper wheel 210 performs the rotary motion and the linear reciprocating motion along the upper guide groove 111, the second upper wheel 230 receives the rotational force from the first upper wheel 210, As a result, the second upper wheel 230 also rotates along the upper guide groove 111 and performs a linear reciprocating motion. The first upper wheel 210 and the second upper wheel 230 may have a sawtooth structure or an interlocking spiral structure on the outer circumferential surface for smooth transfer of force therebetween. Alternatively, a material such as rubber may be formed on the outer circumferential surfaces of the first upper wheel 210 and the second upper wheel 230 to increase the friction force, but is not limited thereto.

The upper eraser 300 is coupled to the upper wheel part 200 and is connected thereto. The upper eraser 300 includes an upper link 330 and a first eraser pad 310. Specifically, one end of the upper link 330 is connected to the second upper wheel 230, it is connected to the eccentric coupling structure coupled to the position off the central axis of the second upper wheel 230. On the other hand, the first eraser pad 310 is coupled to the other end of the upper link 330, the surface contact with the blackboard (B).

Accordingly, when driving the motor of the present invention described above, the crank unit 400 receives the driving force of the motor is rotated, the first upper wheel 210 is the crank unit 400 via the first rocker 500. Receives rotational force from the rotational movement and linear reciprocating motion. The second upper wheel 230, which receives the rotational force from the first upper wheel 210, also performs a rotational movement and a linear reciprocating motion as described above, and the first eraser pad 310 is connected to the second upper wheel 230. The eccentric rotation and reciprocation are performed by receiving force from the second upper wheel 230 through the eccentrically coupled upper link 330. Accordingly, the blackboard B in surface contact with the first eraser pad 310 is wiped by the movement of the first eraser pad 310. That is, according to the present invention, it is possible to perform the cleaning of the blackboard using the first eraser pad 310 that performs the reciprocating motion and the eccentric rotation movement at the same time, it is possible to clean the blackboard cleaning work than the conventional blackboard eraser Will be able to reap.

Meanwhile, as the circumferential ratio of the second upper wheel 230 is greater than that of the first upper wheel 210, the area of the first eraser pad 310 wiping the blackboard B becomes wider, but the moving speed decreases by that amount. In addition, as the circumferential ratio of the second upper wheel 230 is smaller than that of the first upper wheel 210, the eccentric rotation speed of the first eraser pad 310 increases, but it becomes more difficult to install the upper link 330. ) Area is reduced, making it inefficient. Therefore, the circumferential ratio of the first upper wheel 210 and the second upper wheel 230 is preferably 3: 1, but is not limited thereto and may be appropriately changed according to the user's intention.

The crank unit 400 is a portion that transmits the rotational force to the upper wheel portion 200 and the lower wheel portion 700 by receiving the driving force of the motor. The crank unit 400 may be formed in the crank body, the center of the crank body, and a central axis connected to the drive shaft of the motor as described below in the description of FIG. 2. Meanwhile, although the shape of the crank body is illustrated in the form of a rectangle in FIG. 1, this is only one example, and it will be apparent to those skilled in the art that the present invention may be formed in various shapes such as a disc and a polygon. In addition to the details of the crank unit 400 will be described later in the description of FIG.

The lower wheel part 600 is connected to the crank part 400 by the second locker 800, and receives the rotational force of the crank part 400 which is rotated by the driving force of the motor, and thus the second eraser of the lower eraser part 700. The pad 710 is a part for reciprocating and eccentric rotation. The lower wheel part 600 of the present invention includes a first lower wheel 610 and a second lower wheel 630. The first lower wheel 610 is formed in surface contact with the inner upper end of the lower guide groove 131, and one end of the second rocker 800 is coupled to the central axis of the first lower wheel 610. Accordingly, when the crank part 400 rotates, the first lower wheel 610 is rotated by receiving the rotational force through the second rocker 800, and as a result, the central axis of the first lower wheel 610 is the lower guide. A straight reciprocating motion is performed along the groove 131.

The second lower wheel 630 is formed below the first lower wheel 210 and is in surface contact with the inner lower surface of the lower guide groove 131 and the first lower wheel 610. Accordingly, when the first lower wheel 610 rotates and linearly reciprocates along the lower guide groove 131, the second lower wheel 630 receives a rotational force from the first lower wheel 610. As a result, the second lower wheel 230 also rotates along the lower guide groove 131 and performs a linear reciprocating motion. In addition, the description of the first lower wheel 610 and the second lower wheel 630 is the same as in the case of the first upper wheel 210 and the second upper wheel 230, it will be omitted.

The lower eraser 700 is coupled to the lower wheel part 600 and connected to the lower eraser 700. The lower eraser 700 includes a lower link 730 and a second eraser pad 710. Specifically, one end of the lower link 730 is connected to the second lower wheel 630, it is connected in an eccentric coupling structure coupled to the position off the central axis of the second lower wheel 630. On the other hand, the second eraser pad 710 is coupled to the other end of the lower link 730, the surface contact with the blackboard (B).

Accordingly, when driving the motor of the present invention described above, the crank unit 400 is received to receive the driving force of the motor is rotated, the first lower wheel 610 is the crank unit 400 via the second rocker 800. Receives rotational force from the rotational movement and linear reciprocating motion. The second lower wheel 630, which receives the rotational force from the first lower wheel 610, also performs a rotational movement and a linear reciprocating motion as described above, and the second eraser pad 710 is connected to the second lower wheel 630. The eccentric rotation and reciprocating motion is performed by receiving a force from the second lower wheel 630 through the eccentrically coupled lower link 730. Accordingly, the board B in surface contact with the second eraser pad 710 is wiped by the movement of the second eraser pad 710.

That is, to summarize the overall operation of the present invention with reference to FIG. 1, when the crank unit 400 rotates according to the driving of the motor, the first upper wheel 210 and the second upper wheel 230 may be rotated. At the same time, linear movement is performed from left to right. Accordingly, the first eraser pad 310 cleans the blackboard B while moving from left to right at the same time as the eccentric rotation movement. On the other hand, the first lower wheel 610 and the second lower wheel 630 performs a linear movement from the right to the left at the same time as the rotational movement, accordingly, the second eraser pad 610 at the same time from the right at the same time as the eccentric rotation The board (B) is cleaned while moving to the left. According to the present invention, it is possible to achieve the effect of realizing the automatic blackboard eraser with a simple structure that can move two eraser pads at the same time using a single motor, and to reduce the manufacturing cost by implementing a simple structure.

In particular, the above-described automatic blackboard eraser structure of the present invention can be seen that it consists of a 1 degree of freedom structure. The degree of freedom is simply defined as the number of driving sources required for driving a device. More specifically, when a line position or an angular position of a link is determined, a degree of freedom is called a single degree of freedom when all types of devices are determined. In general, the higher the degree of freedom, but can use a variety of operations, the control method is very difficult, there is a problem that the manufacturing cost increases according to the number of motors. Therefore, when the operation can control a complicated mechanism with one degree of freedom, it is possible to reduce the manufacturing cost and easy control by reducing the number of motors. When the skeleton part that determines the movement of the mechanism is a link, the part that connects two or more links is a joint, and the part that uses a cam or gear structure for the connection between the links is called a high-order joint, the number of links (N), the number of joints (J) If the number Ih of the high order joints is known, the degree of freedom F of the instrument can be calculated by the Gruebler equation described below.

F = 3 (N-1) -2J-Ih

In the case of the present invention, it can be seen that the number of links is a total of seven, the number of joints is a total of eight, the number of high-order joints is a total of one, and the degree of freedom calculated by the Grubler equation described above is one.

That is, according to the present invention, by forming the automatic blackboard eraser in one degree of freedom structure, it can be seen that the effect of simple control, manufacturing cost reduction effect and driving power reduction effect by using a single motor.

Figure 2 is a side cross-sectional view of the automatic blackboard eraser shown in Figure 1 viewed from the side.

1 and 2, the crank unit 400 of the present invention is connected to the center of the crank body 410, 430 and the crank body 410, 430, as described above in the description of Figure 1, the drive shaft of the motor And a central axis 450 connected to the axis.

In particular, in the case of the crank bodies 410 and 430, the first crank body 410 and the second crank body 430 formed spaced apart from the first crank body 410, the central axis 450 is the first crank It may be made of a structure for connecting the center of the body 410 and the center of the second crank body 430. That is, the crank part 400 of the present invention may be made of an H-shaped structure, and thus, when the crank bodies 410 and 430 rotate by the driving of the motor, the first rocker 500 and the second rocker 800 are rotated. ) Can be prevented.

Meanwhile, in FIG. 2, the first locker 500 is connected to the first crank body 410 and the second locker 800 is connected to the second crank body 430, but this is one example. In addition, the first locker 500 may be configured to be connected to the second crank body 430 and the second locker 800 may be connected to the first crank body 410.

The central shaft 450 rotates the crank bodies 410 and 430 by receiving a driving force by being coupled with the motor. The central shaft 450 of the present invention may be made of a structure that is directly connected to the drive shaft of the motor, it may be made of a structure that is coupled to the drive shaft of the motor via the bevel gear. On the other hand, the motor used in the present invention is preferably a DC motor, but is not limited thereto.

Description of the configuration other than that is the same as described above in the description of Figure 1, it will be omitted. In addition, the features of the upper wheel portion and the upper eraser of the present invention is the same as the lower wheel portion and the lower eraser, the description will be described with respect to the upper wheel portion and the upper eraser.

Figure 3 illustrates an embodiment of the upper wheel portion and the upper eraser portion according to the present invention.

1 to 3, the upper wheel part of the present invention includes a first upper wheel 210 and a second upper wheel 230 as described above in the description of FIG. 1. At this time, one end of the first rocker 500 is connected to the center P1 of the first upper wheel 210, and one end of the upper link 330 is located at a position away from the center P2 of the second upper wheel 230. Is eccentrically coupled. Meanwhile, in the present embodiment, the upper wheel part may further include a guide 320 to prevent the upper link 330 from being separated. In this case, the guide 320 may have a structure connected to the center P1 of the first upper wheel 210 and the first rocker 500, but is not limited thereto.

On the other hand, the upper link 330 is preferably made of a structure in which bending is formed as shown in FIG. This is to transfer the rotational force and linear movement force of the second upper wheel 230 to the first eraser pad 310 formed in surface contact with the blackboard.

In addition, two or more pins 331, 332, and 333 inserted into the first eraser pad 310 are formed at the other end of the upper link 330, so that the upper link 330 is firmly connected to the eraser pad 310. It is preferred to be combined.

On the other hand, the configuration features of the lower wheel portion and the lower eraser portion of the present invention is the same as the above-described configuration of the upper wheel portion and the upper eraser, the description thereof will be omitted.

Figure 4 shows an embodiment of the rear structure of the upper wheel portion according to the present invention.

Referring to FIG. 4, the centers of the first upper wheels 210 and the centers of the second upper wheels 230 are connected to the rear surfaces of the first upper wheels 210 and the second upper wheels 230. The wheel detachment prevention part 220 may be further provided to prevent the first upper wheel 210 and the second upper wheel 230 from being separated from each other. In this case, the wheel detachment prevention part 220 is connected only to the centers of the first upper wheel 210 and the second upper wheel 230, and thus, preferably does not interfere with the rotational movement of both upper wheels.

Figure 5 shows a modified embodiment of the body portion according to the present invention.

1 to 5, the body part according to a modified embodiment of the present invention further includes an upper wheel guide bar 113 in the upper guide groove 111 so that the first upper wheel 210 and the second upper wheel ( The possibility of departure of 230 can be further prevented. In addition, although not shown in the drawing, grooves may be further formed on the inner lower surface and the inner upper surface of the upper guide groove 111 to allow the first upper wheel 210 and the second upper wheel 230 to be partially inserted into the wheel. It is also possible to change the design to prevent it.

Figure 6 shows the results of simulating the movement trajectory of the eraser pad according to the present invention. In the simulation, the size of the blackboard was set to 2400cm in width and 1200cm in length. In addition, the radius of the first upper wheel and the first lower wheel is set to 150mm, the radius of the second upper wheel and the second lower wheel is set to 50mm. In addition, the length of the upper link and the lower link is set to 900mm, the length of the first eraser pad and the second eraser pad is 470mm, the length of the first rocker and the second rocker is set to 1500mm, the rotation speed of the motor is set to 360deg / sec It was.

The red line shown in FIG. 6B is a result of measuring three points A, B, and C shown in FIG. 6A as observation points. Looking at Figure 6 (b), it can be seen that the first eraser pad and the second eraser pad of the present invention covers the entire area of the blackboard, according to which the portion of the blackboard does not wipe when using the automatic blackboard eraser of the present invention You can see that this doesn't happen at all.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Those skilled in the art will appreciate that many suitable modifications and variations are possible in light of the present invention. Accordingly, all such suitable modifications and variations and equivalents should be considered to be within the scope of the present invention.

100: body
110: upper body 111: upper guide groove
130: lower body 131: lower guide groove
200: upper wheel part
210: first upper wheel 230: second upper wheel
300: upper eraser
310: first eraser pad 330: upper link
400: crank portion 410: first crank body
430: second crank body 450: central axis
500: first locker 800: second locker
600: lower wheel part
610: first lower wheel 630: second lower wheel

Claims (14)

A body part having an upper guide groove formed on an upper portion of the blackboard and a lower guide groove formed on the lower portion of the blackboard;
An upper wheel part formed in the upper guide groove;
An upper eraser portion connected to the upper wheel portion and having a first eraser pad in surface contact with the blackboard;
A crank part formed at the center of the blackboard;
A motor coupled to a center of the crank part and transmitting power to the crank part;
A first locker having one end connected to the upper wheel part and the other end connected to the crank part;
A lower wheel part formed in the lower guide groove and formed at a position symmetrical with the upper wheel part based on the crank part;
A lower eraser portion connected to the lower wheel portion and provided with a second eraser pad in surface contact with the blackboard;
A second rocker having one end connected to the lower wheel part and the other end connected to the crank part;
Automatic blackboard eraser that includes.
The method according to claim 1,
The upper wheel portion,
A first upper wheel in surface contact with an inner bottom surface of the upper guide groove, and having a central axis connected to the first rocker;
A second upper wheel formed to be in surface contact with the upper surface of the upper guide groove and the first upper wheel; Automatic blackboard eraser that includes.
The method according to claim 2,
An automatic blackboard eraser, characterized in that the circumference ratio of the first upper wheel and the second upper wheel is 3: 1.
The method according to claim 2,
The upper eraser portion,
One end is eccentrically coupled to the second upper wheel, the other end of the automatic blackboard eraser comprising an upper link coupled with the first eraser pad.
The method according to claim 2,
The body portion
And an upper wheel guide bar formed between the first upper wheel and the second upper wheel.
The method according to claim 1,
The lower wheel portion,
A first lower wheel in surface contact with an inner upper surface of the lower guide groove and having a central axis connected to the second rocker;
A second lower wheel formed to be in surface contact with the inner bottom surface of the lower guide groove and the first lower wheel; Automatic blackboard eraser that includes.
The method of claim 6,
Automatic blackboard eraser, characterized in that the circumferential ratio of the first lower wheel and the second lower wheel is 3: 1.
The method of claim 6,
The lower eraser portion,
An automatic blackboard eraser comprising an upper link having one end eccentrically coupled with the second lower wheel and the other end coupled with the second eraser pad.
The method of claim 6,
The body portion
And a lower wheel guide bar formed between the first lower wheel and the second lower wheel.
The method according to claim 1,
The crank part,
An automatic blackboard eraser comprising a crank body and a central axis formed at the center of the crank body.
The method of claim 10,
The crank body,
A first crank body and a second crank body spaced apart from the first crank body,
The central axis is,
An automatic blackboard eraser having a structure having one end connected to a center of the first crank body and the other end connected to a center of the second crank body.
The method of claim 11,
Any one of the first crank body and the second crank body is eccentrically coupled to the other end of the first locker,
The other one of the first crank body and the second crank body is an automatic blackboard eraser is eccentrically coupled with the other end of the second locker.
The method according to any one of claims 1 to 12,
The motor includes:
Automatic blackboard eraser characterized in that the DC motor.
The method according to claim 13,
The drive shaft of the motor,
An automatic blackboard eraser which is connected to the crankshaft center and the shaft by a bevel gear.

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