KR200355275Y1 - A fold-type ruller used as a protractor - Google Patents

Abstract

The present invention relates to a folding protractor combine, and more particularly to a folding protractor combiner that can draw a straight line from the center at all angles, and can draw a straight line without an error.

Folding protractor combined according to the present invention, the first edge of the straight line is formed on one side in the width direction, has a center angle of a certain width and obtuse angle on the upper surface at one end in the longitudinal direction as a center point A first rail groove having an arc shape is formed, and a first bar having a locking groove or a protrusion formed along at least one sidewall of at least one sidewall of both sidewalls in the width direction of the first rail groove, and extending in the width direction. A second edge of a straight line is formed on one side, and an arc-shaped second rail groove having a center angle of a certain width and an obtuse angle at one end in the longitudinal direction and having a point on the corner as a center point is formed. A second bar having a locking groove or a protrusion formed on at least one sidewall of the two side walls in the width direction of the rail groove along the sidewall thereof; It has a width and a center angle that can be slid in the direction, and an arc shape having a predetermined point as a center point, and engaging with the engaging groove or the engaging protrusion on the side wall which is in contact with the side wall of the first rail groove in which the engaging groove or the engaging protrusion of the first rail groove is formed. A circular arc-shaped first rail portion having a biting protrusion or locking groove, and a width and a center angle inserted into the second rail groove and slidable in the circumferential direction, and having the same point as the center point of the first rail portion. A circular arc-shaped arc formed with a locking projection or a locking groove which is engaged with the locking groove or the locking projection of the second rail groove on the side wall which is in contact with the side wall of the second rail groove formed with the locking groove or the locking projection of the second rail groove. 2 rail portions, a center angle formed between the first edge or the extension line of the first rod and the end of the first rail groove at the distal side of the first rod and the end of the second rod And a connection rail having a rail connection portion connecting the first rail portion and the second rail portion to each other, having a center angle greater than or equal to the sum of the center angle formed by the second edge or the extension line thereof and the end of the second rail groove. It is characterized by.

Description

Folding protractor combined use {A FOLD-TYPE RULLER USED AS A PROTRACTOR}

The present invention relates to a folding protractor combine, and more particularly to a folding protractor combiner that can draw a straight line from the center at all angles, and can draw a straight line without an error.

The ruler is to measure the length of a straight line or to draw a straight line, and the protractor is to measure an angle or draw a circular arc or a fan with a constant center angle. Generally, the ruler and protractor are provided separately and used for each purpose. In particular, a ruler and protractor are used together for the construction of arcs or sectors. Therefore, it is troublesome to draw an arc or a fan using a ruler and a protractor separately provided. Therefore, there have been various attempts for a protractor combined with a ruler and a protractor.

8 is an exploded perspective view showing a conventional folding protractor combined ruler equipped with a ruler and a protractor as described above.

Referring to the drawings, the conventional folding protractor combine is formed by folding the pair of chairs (1, 2) foldable. The folding protractor combines the edges 3 and 4 of the straight line for each of the pair of chairs 1 and 2 to draw a straight line. The corners 3 and 4 are generally marked with scales to indicate their length. The pair of chairs 1 and 2 are rotatably connected such that the edges 3 and 4 have various angles. Thus, the center of rotation of the pair of chairs 1, 2 should be located on the edges 3, 4. Referring to the drawings, at the bottom of one of the pair of chairs 1 and 2, an arc-shaped rail groove 5 centering on a point 3a on the corner 3 is formed, and the other ruler 2 On the upper surface of the edge of the circular arc-shaped rail (6) centering on a point (4a) on the corner 4, the pair of chairs (by engaging the rail (5) to engage the rail groove 6) 1,2) are rotatably connected to each other. The pair of chairs 1 and 2 connected as described above has an angle between the edges 3 and 4 extending from 0 degrees to 180 degrees. One of the pair of chairs 1 and 2 is marked with a scale for indicating an angle along the rail groove 5 or the rail 6, and the other is marked with a reference line. However, since the center of rotation of the pair of chairs 1 and 2 is located on the edges 3 and 4, the rail groove 5 in a fully extended state such that the angle between the edges 3 and 4 is 180 degrees. ) And the rails (6) must have overlapping parts to engage each other. To this end, at least one of the rail groove 5 and the rail 6 should have a central angle greater than 180 degrees. In the drawing, the center angles of the rail grooves 5 and the rails 6 are about 270 degrees around the edges of the edges 3 and 4, so that the rail grooves 5 and the rails 6 are The 90 degree portions overlap each other in an unfolded state such that the angle between the edges 3 and 4 is 180 degrees. Figure 9 conceptually illustrates the operation of the conventional folding protractor combined as described above. (A) to (e) of FIG. 9 each represent an angle of 0 degrees (completely folded), 40 degrees, 90 degrees, 140 degrees, and 180 degrees (fully unfolded) between the corners 3 and 4. It is shown in order. Referring to the drawings, the conventional folding protractor combines each of the rail grooves 5 and the rails 6 in a state in which the angle between the edges 3 and 4 is unfolded at an obtuse angle, that is, an angle of 90 to 180 degrees. The corners (3, 4) protrude forward.

As described above, in the conventional protractor combiner, the rail groove and the rail protrude toward the edge in a state where the angle formed by the corners of the pair of chairs is unfolded at an obtuse angle. Therefore, the conventional protractor combiner has a disadvantage in that it is impossible to draw a line from the center, that is, the position where the corners meet in an unfolded obtuse state.

On the other hand, in the conventional protractor combiner, one of the pair of chairs is connected to the upper part of the other chair, so that some of the edges of the chair located at the top are not in contact with the ground to draw a straight line. Accordingly, the writing instrument can not draw a straight line against the corner at the corner portion that is not in contact with the ground, and thus there is a disadvantage in that an error is generated.

In addition, the conventional protractor combiner may show the angle, but has a disadvantage that a separate compass must be used to draw an arc or a fan.

The present invention is to solve the above problems, the object of the present invention is not only to draw a line from the center even when the angle between the corners is an obtuse angle, but also to draw a straight line when all the edges from the center touch the ground It is to provide a folding protractor combined to prevent the.

In addition, another object of the present invention is to provide a folding protractor combiner capable of drawing an arc by allowing the writing instrument to be supported at a certain position of a pair of chairs.

1 is an exploded perspective view showing a folding protractor combined ruler according to an embodiment of the present invention

Figure 2 is an exploded perspective view showing in detail a portion of the folding protractor combiner according to an embodiment of the present invention

3 is a cross-sectional view showing a cross section at A-A, B-B, C-C, and D-D of FIG.

4 is a conceptual diagram conceptually illustrating a relationship between a first bar, a second bar, and a connection rail of a folding protractor combined device according to an embodiment of the present invention;

Figure 5 is a perspective view showing a coupling state of the writing instrument support of the folding protractor combined according to an embodiment of the present invention

6 is a cross-sectional view showing a cross section in E-E of FIG.

7 is a conceptual diagram conceptually showing the operation of the folding protractor combined according to an embodiment of the present invention

8 is an exploded perspective view showing a conventional folding protractor combined ruler

9 is a conceptual diagram conceptually showing the operation of a conventional folding protractor combined

<Short Description of Main Reference Signs>

10 First Bar 11 First Corner

11a corner cutout 11b angle mark

12 Center point 13 First rail groove

13a Hanging groove 15 Connecting part

19 Seating protrusions 20 2nd bar

21 2nd corner 21a Corner extension

21b receiving hole 22 center point

23 2nd rail groove 23a Jam groove

25 Connecting groove 30 Connecting rail

31 Rail connection 33 First rail

33a Engaging protrusions 35 2nd rail part

35a Jamming 40 Writing Instruments

41 Protrusion 43 Writing instrument insertion hole

45 Seating groove

In order to achieve the above object, the foldable protractor combined device according to the present invention has a straight first corner formed at one side in the width direction, and has a center angle of a predetermined width and an obtuse angle at one end in the longitudinal direction. An arc-shaped first rail groove having a point on a corner as a center point is formed, and at least one side wall of both side walls in the width direction of the first rail groove has a first engaging groove or a protrusion formed along the side wall. A second arc-shaped second bar having a center angle of a certain width and an obtuse angle formed at a bottom at one end in the longitudinal direction, and having a center angle at one end in the width direction, with a center point A second bar having a rail groove, and having a locking groove or a protrusion formed along at least one sidewall of at least one sidewall of both sidewalls in the width direction of the second rail groove; And a circular arc shape having a width and a center angle inserted into the first rail groove and sliding in the circumferential direction and having a predetermined point as a center point and having a locking groove or a locking protrusion of the first rail groove. A first rail portion having an arc shape having a locking protrusion or a locking groove engaged with the locking groove or the locking projection on the side wall which is in contact with the side wall, and having a width and a center angle inserted into the second rail groove and slidable in the circumferential direction; A circular arc shape having the same point as the center point of the first rail part, and the sidewalls which are in contact with the sidewalls of the second rail grooves in which the engaging grooves or the engaging protrusions of the second rail grooves are engaged with the engaging grooves or the engaging protrusions of the second rail grooves. An arc-shaped second rail portion having a biting protrusion or catching groove, and the first edge or an extension line thereof and the end of the first rail groove are formed at the end side of the first rod. The loop has a central angle greater than or equal to the sum of the central angle formed by the second edge or the extension line and the end of the second rail groove at the distal side of the second bar and connects the first rail part and the second rail part. It characterized in that it comprises a connection rail having a rail connection.

Accordingly, the first bar and the second bar are rotatably connected to each other by the connecting rail in a state where the center point is coincident with each other. In particular, the connecting rail is located between the first bar and the second bar does not protrude to the outside of the first and second corners can draw a straight line from the center point along the first and second corners Will be.

In addition, the folding protractor combiner according to the present invention, the first bar is cut off from the center side to the end of the first bar to form a corner cutout, at a position away from the bottom surface of the cut end end An angle display protrusion is formed to protrude in the circumferential direction and extend to an extension line of the first edge, and the second bar extends downward from the center point at the opposite side of the terminal from the center point by the thickness of the first bar. The edge extending portion is formed, and the receiving hole for accommodating the angle display protrusion at the position where the angle display projection is in contact with the rotation of the first bar and the second bar is characterized in that the corner extension portion is formed.

At one end of the second bar overlapped with an upper portion of the first bar, the edge extending part extending downward by the thickness of the first bar is in contact with the ground. Accordingly, the edges of the second bar abut the ground from the center point, so that an error is not generated when drawing a straight line.

In addition, the folding protractor combine according to the present invention, the guide groove is formed in the upper surface of the second bar extending in the longitudinal direction with a predetermined width parallel to the second edge, the guide on the surface in contact with the upper surface of the second bar And a writing instrument support having a protrusion to be engaged with the groove and having a writing instrument insertion hole for inserting the writing instrument at the portion where the second edge is located.

A circular arc can be easily drawn by inserting a writing instrument into the writing instrument insertion hole of the writing instrument support and rotating the second bar.

Hereinafter, with reference to the embodiment shown in the drawings will be described in more detail the folding protractor combined according to the present invention.

1 is an exploded perspective view showing a folding protractor combined according to an embodiment of the present invention, Figure 2 is an exploded perspective view showing a part of the folding protractor combined according to an embodiment of the present invention in detail, Figure 3 2 is a cross-sectional view showing a cross section in AA, BB, CC, and DD, Figure 4 is a relationship between the first rail groove, the second rail groove and the connection rail of the folding protractor combined according to an embodiment of the present invention Conceptually shown is a conceptual diagram, Figure 5 is a perspective view showing a coupling state of the writing instrument support of the folding protractor combined according to an embodiment of the present invention, Figure 6 is a cross-sectional view showing a cross section in the EE of FIG.

Referring to the drawings, the folding protractor combiner according to the present invention includes a first bar 10, the second bar 20, the connecting rail 30, and the writing instrument support (40).

The first bar 10 and the second bar 20 are rotatably connected to each other by the connection rails 30, and rotate from the fully folded state to the fully extended state in the connected state. That is, the first bar 10 and the second bar 20 are rotated in a range where the angle formed between the first edge 11 and the second edge 21 is 180 degrees from 0 degrees. .

The first bar 10 is a rod member having a straight first edge 11 on one side in the width direction. An arc-shaped article having a predetermined width and an obtuse-center angle α1 having a point on the first edge 11 as a center point 12 at one end in the longitudinal direction of the first rod 10. One rail groove 13 is formed. The first rail portion 33 of the connection rail 30 is inserted into and coupled to the first rail groove 13. Here, the center angle α1 of the first rail groove 13 should be greater than 90 degrees and smaller than 180 degrees. That is, the center angle α1 of the first rail groove 13 is an obtuse angle. First, both sides of the first rail groove 13 are disposed so that the first rail portion 33 of the connection rail 30 inserted into and coupled to the first rail groove 13 is not separated from the first rail groove 13. Steps 14a and 14b should be formed. As described above, since the arc center of the first rail groove 13 is located at the first corner 11, the step 14a and 14b may be used to form the stepped parts 14a and 14b. The center angle α1 of the rail groove 13 should be smaller than 180 degrees. The first bar 10 and the second bar 20 rotate relative to each other in a range where an angle formed between the first edge 11 and the second edge 21 forms 0 to 180 degrees. do. That is, the first bar 10 and the second bar 20 are rotated up to 90 degrees with respect to the connection rail 30. However, the first rail portion 33 of the connection rail 30 is accommodated in the first rail groove 13. Therefore, the stepped bars 14a and 14b of the first rail groove 13 and the latching bars 34a and 34b of the first rail part 33 are not caught and interfered with each other by the rotation of the first bar 10. The center angle α1 of the first rail groove 13 should be greater than 90 degrees greater than the center angle β1 of the first rail portion 33. Since the first rail portion 33 has a center angle β1 greater than at least 0 degrees, the center angle α1 of the first rail groove 13 should be greater than 90 degrees. Therefore, the central angle α1 of the first rail groove 13 is larger than 90 degrees and smaller than 180 degrees, that is, an obtuse angle.

On the other hand, at least one sidewall of both side walls in the width direction of the first rail groove 13, the first rail portion 33 inserted into each of the first rail groove 13 does not fall out; The engaging groove or the engaging projection for engaging the engaging projection or the engaging groove formed on both side walls of the part 33 is formed long along the side wall thereof. In the drawing, the locking grooves 13a are formed on both side walls of the first rail groove 13, and the locking protrusions 33a are received and engaged in the locking grooves 13a on both side walls of the first rail portion 33. An embodiment in which is formed is shown.

On the other hand, between the end of the first edge 11 and the first rail groove 13 at one end end side of the first bar 10, the connection portion receiving groove of a depth smaller than the first rail groove 13 ( 15) is formed. The connection part accommodating groove 15 accommodates a portion of the connection rail 30 in the depth direction of the rail connection part 31. Therefore, when the height of the rail connecting portion 31 is equal to or less than the sum of the depths of the connecting portion receiving groove 15 of the first bar 10 and the connecting portion receiving groove 25 of the second bar 20. The first bar 10 and the second bar 20 are coupled so that the top and bottom surfaces are in contact with each other.

Meanwhile, the second bar 10 overlapping the upper portion of the first bar 10 may be formed so that the second edge 21 contacts the ground at one end overlapped with one end of the first bar 10. The edges 21a of which the two edges 21 extend downward by the thickness of the first bar 10 are formed. However, the edge extension portion 21a interferes with the first edge 11 of the first bar 10 in a state where the first bar 10 and the second bar 20 are fully unfolded. Therefore, the first edge 11 of the first bar 10 is cut off from the center point 12 to the end of the end side to form a corner cutout portion 11a.

On the other hand, when the corner cutout portion 11a is formed as described above, the first bar 10 and the second bar 20 overlap with each other, so that some of the parts that can display the angle disappear and some angles cannot be displayed. Accordingly, the first bar 10 protrudes in the circumferential direction at a position separated by a predetermined height from the bottom surface of the edge cutting portion 11a and extends to the extension line of the first edge 11. ) Is provided. Accordingly, the first bar 10 and the second bar 20 overlap each other in the range of 0 degrees to 180 degrees, thereby displaying an angle of 0 degrees to 180 degrees.

The second bar 20 is a rod member having a straight second edge 11 on one side in the width direction, and is substantially the same as the first bar 10. An arc-shaped material having a predetermined width and an obtuse-center angle α2 at one end of the second rod 20 in the longitudinal direction on the second edge 21 as the center point 22. Two rail grooves 23 are formed. The second rail portion 35 of the connection rail 30 is inserted into and coupled to the second rail groove 23. Here, the center angle α2 of the second rail groove 23 should be greater than 90 degrees and smaller than 180 degrees. That is, the center angle α2 of the second rail groove 23 is an obtuse angle. First, the second rail portion 35 of the connection rail 30 inserted into the second rail groove 23 is disposed on both sides of the second rail groove 23 so as not to be separated from the second rail groove 23. Steps 24a and 24b should be formed. As described above, since the arc center of the second rail groove 23 is located at the second corner 21, the second step 24a and 24b may be formed to form the second step 24a and 24b. The center angle α2 of the rail groove 23 should be smaller than 180 degrees. The first bar 10 and the second bar 20 rotate relative to each other in a range where an angle formed between the first edge 11 and the second edge 21 forms 0 to 180 degrees. do. That is, the first bar 10 and the second bar 20 are rotated up to 90 degrees with respect to the connection rail 30. However, the second rail portion 35 of the connection rail 30 is accommodated in the second rail groove 23. Accordingly, the stepped bars 24a and 24b of the second rail groove 23 and the locking step 36a and 36b of the second rail part 35 do not interfere with each other by the rotation of the second bar 20. The center angle α2 of the second rail groove 23 should be greater than 90 degrees greater than the center angle β2 of the second rail portion 35. Since the second rail portion 35 has a center angle β2 greater than at least 0 degrees, the center angle α2 of the second rail groove 23 should be greater than 90 degrees. Therefore, the center angle α2 of the second rail groove 23 is larger than 90 degrees and smaller than 180 degrees, that is, an obtuse angle.

On the other hand, the second rail portion so that the second rail portion 35 inserted into the second rail groove 23 does not fall into at least one sidewall of both side walls in the width direction of the second rail groove 23. The engaging grooves or the engaging projections for engaging the engaging projections or the engaging grooves formed on both side walls of the 35 are formed long along the side walls thereof. In the drawing, the locking grooves 23a are formed on both side walls of the second rail groove 23, and the locking protrusions 35a are received and engaged with the locking grooves 23a on both side walls of the second rail part 35. An embodiment in which is formed is shown.

On the other hand, between the end of the second edge 21 and the second rail groove 23 at one end of the second bar 10, the connection portion receiving groove of a depth smaller than the second rail groove (23) ( 25) is formed. As described above, a portion in the depth direction of the rail connection portion 31 of the connection rail 30 is accommodated in the connection portion accommodation groove 25.

On the other hand, as described above, the second bar 20 has the first bar 10 so that the second edge 21 abuts on the ground from the center point 22 on the opposite side of the terminal with respect to the center point 22. An edge extension portion 21a is formed which extends downward by the thickness of.

In addition, the first bar 10 and the second bar 20 is rotated relative to each other relative to each other in a fully unfolded state so that the angle display projection (11b) abuts the edge extending portion (21a) so that the interference The corner extension portion 21a is provided with a receiving hole 21b in which the angle display protrusion 11b can be accommodated at a position where the angle display protrusion 11b abuts.

On the other hand, the upper surface of the second bar 20 is formed with a guide groove 29 of a predetermined width parallel to the second edge 21 is formed long in the longitudinal direction. The guide groove 29 is accommodated and coupled to the protrusion 41 of the writing instrument support 40.

The connecting rail 30 is for rotatably connecting the first bar 10 and the second bar 20. The connecting rail 30 has an arc shape as a whole by connecting the first rail part 33 and the second rail part 35 to both sides with the rail connection part 31 interposed therebetween.

The first rail portion 33 is an arc shape having a width and a center angle β1 inserted into the first rail groove 13 and slidable in the circumferential direction and having a predetermined point as the center point 32. The first rail groove 13 has a locking groove or a locking groove formed to engage with the locking groove or the locking projection on a side wall contacting the side wall of the first rail groove 13 on which the locking groove or the locking projection is formed.

The second rail portion 35 has a width and a center angle β2 that can be inserted into the second rail groove 23 and slide in the circumferential direction, such as the center point 32 of the first rail portion 35. A circular arc-shaped height having a center point as a locking groove or a locking projection of the second rail groove 23 on a sidewall which is in contact with the side wall of the second rail groove 23 on which the locking groove or the locking projection of the second rail groove 23 is formed. It has a locking projection or locking groove formed to engage.

Meanwhile, the sum of the center angle β1 of the first rail portion 33 and the center angle β2 of the second rail portion 35 is the center angle α1 of the first rail groove 13 and the second rail groove. It is preferable that it is 180 or more less than the sum of the center angles alpha 2 of (23). This is because the relative rotation angle of the first bar 10 and the second bar 20 should be up to 180, the first bar 10 and the connecting rail 30 of the relatively rotatable range This is because the sum of the rotation angle and the rotation angle within the range in which the second bar 20 and the connection rail 30 are relatively rotatable should be 180 degrees or more. In the drawing, the sum of the center angle beta 1 of the first rail part 33 and the center angle beta 2 of the second rail part 35 is equal to the center angle alpha 1 of the first rail groove 13 and the second rail groove. 180 less than the sum of the center angles α2 of 23, the center angle β1 of the first rail portion 33 and the center angle β2 of the second rail portion 35 are the same, and the first rail groove is the same. An embodiment in which the center angle α1 of (13) and the center angle α2 of the second rail groove 23 are equal to each other is shown.

The rail connecting portion 31 is a portion for connecting the first rail portion 33 and the second rail portion 35 to each other. The rail connecting portion 31 is accommodated in the connecting portion accommodating grooves 15 and 25 by the connecting rail 30 in a state in which the first rod 10 and the second rod 20 are connected to each other. The rail connecting portion 31 has a center angle γ1 and a second angle formed between the first edge 11 or its extension line and the end of the first rail groove 13 at the distal side of the first rod 10. At the distal side of the bar 20 has a central angle (δ) of at least the sum of the center angle (γ2) formed by the second edge 21 or its extension line and the end of the second rail groove 23. This is because the first bar 10 and the second bar 20 are fully folded, that is, the angle between the first edge 11 and the second edge 21 is 0 degrees. In the circumferential direction of the terminal step 14b and the second rail groove 23 in the circumferential direction of the first rail groove 13 located at one end of the rod 10 and the second bar 20, respectively. One step 34b of the first rail portion 33 located on both sides of the terminal step 24b and one step step 36b of the second rail part 35 do not interfere with each other.

The writing instrument support 40 is for supporting the end of the writing instrument to draw an arc by rotating the second bar 20, the writing instrument support 40 is installed. The writing instrument support 40 is formed with a protrusion 41 which is inserted into the guide groove 29 is coupled to the upper surface of the second bar 20, the guide groove 29 is formed, the corner ( 21) The writing instrument insertion hole 43 for inserting the writing instrument into the positioned portion is formed. The writing instrument support 40 is moved along the guide groove 29 in the longitudinal direction of the second bar 20, the second bar in the state in which the end of the writing instrument is inserted into the writing instrument insertion hole 43 Rotating 20 allows drawing an arc with the desired center angle of the desired radius. On the other hand, the writing instrument support 40 has a seating groove 45 in the bottom surface in contact with the upper surface of the first bar 10 in a state where the first bar 10 and the second bar 20 is completely folded. Is formed is formed on the upper surface of the first rod 10, the seating projection 19 is seated. When the first and second bars 10 and 20 are seated in the seating recess 45, the first and second bars 20 are not easily unfolded in a folded state.

Figure 7 is a conceptual diagram conceptually showing the operation of the folding protractor combined according to an embodiment of the present invention.

Referring to FIG. 7, the first bar 10 and the second bar 20 are connected by the connection rails 30 to rotate in a range of 0 degrees to 180 degrees. Each of (a) to (e) of FIG. 7 has angles of 0 degrees (completely folded), 40 degrees, 90 degrees, 140 degrees, and 180 degrees between the first edge 11 and the second edge 21. Figures (in fully expanded state) are shown in order. Referring to the drawings, the folding protractor combiner according to an embodiment of the present invention is made even when the angle between the first edge 11 and the second edge 21 is unfolded, that is, at an angle of 90 degrees or more and 180 degrees or less It can be seen that a line can be drawn from the center where the first corner 11 and the second corner 11 meet.

Folding protractor combiner according to the present invention having the configuration as described above has the advantage that can draw a line from the center even when the angle between the corners of each of the pair of bar bar unfolded at an obtuse angle.

In addition, the folding protractor combiner according to the present invention is not an error when drawing a straight line along the corner because all the corners of the bar in contact with the ground in the overlapped portion.

In addition, the folding protractor combiner according to the present invention has the advantage that it is easy to draw a circular arc having a desired radius and center angle by allowing the writing instrument to be supported at a certain position of one of the pair of chairs.

The folding protractor combiner described above and illustrated in the drawings is only one embodiment for carrying out the present invention, and should not be construed as limiting the technical spirit of the present invention. The scope of protection of the present invention is determined only by the matters described in the following Utility Model Registration Claims, and the embodiments of the present invention which have been improved and changed without departing from the gist of the present invention are obvious to those skilled in the art. As long as it is one of the protection scope of the present invention.

Claims (3)

A straight first edge is formed at one side in the width direction, and an arc-shaped first rail groove is formed at one end in the longitudinal direction with a center angle of a predetermined width and an obtuse angle on the upper surface thereof, with a point on the corner as a center point. A first bar having a locking groove or a protrusion formed along at least one sidewall of at least one sidewall of both sidewalls in the width direction of the first rail groove; A straight second corner is formed at one side in the width direction, and an arc-shaped second rail groove is formed at one end in the longitudinal direction with a center angle of a constant width and an obtuse angle at the bottom and a point on the corner as a center point. A second bar having a locking groove or a protrusion formed along at least one sidewall of at least one sidewall of both sidewalls in the width direction of the second rail groove; A circular arc shape having a width and a center angle inserted into the first rail groove and sliding in the circumferential direction and having a predetermined point as a center point and abutting the sidewall of the first rail groove having the engaging groove or the engaging protrusion of the first rail groove. The first rail has an arc-shaped first rail portion having a locking projection or locking groove engaged with the locking groove or the locking projection on the side wall, and a width and a center angle inserted into the second rail groove to slide in the circumferential direction. A circular arc shape having a center point at the same point as a part of the center point, and a locking protrusion engaged with the locking groove or the locking protrusion of the second rail groove on a sidewall which is in contact with the sidewall of the second rail groove where the locking groove or the locking protrusion of the second rail groove is formed. Or an arc-shaped second rail portion having a locking groove formed thereon, and a first edge or an extension line thereof and an end of the first rail groove formed at the end side of the first rod. Rail connection portion connecting the first rail portion and the second rail portion having a central angle of at least the sum of the center angle formed by the second edge or its extension line and the end of the second rail groove at the center angle and the distal side of the second bar; Folding protractor combined ruler comprising a connection rail having a. The method of claim 1, The first bar has a first edge cut from the center point to the end at its distal end to form a corner cutout, and protrudes in a circumferential direction at a position away from the bottom surface of the distal end of the cutout to extend the first edge. An angle display protrusion extending to is formed, The second bar has an edge extending portion extending downward from the center point by the thickness of the first bar from the center point opposite to the end of the center point, the angle of the angle by the rotation of the first bar and the second bar The folding protractor combined part characterized in that the receiving hole in which the angle display projection is accommodated at the position where the display projection abuts is formed in the corner extension portion. The method according to claim 1 or 2, The upper surface of the second bar is formed with a guide groove extending in the longitudinal direction with a predetermined width parallel to the second corner, And a writing instrument supporter on a surface in contact with the upper surface of the second bar, the protrusion being engaged with the guide groove, and having a writing instrument insertion hole for inserting the writing instrument in the portion where the second edge is located. Folding protractor combined.