Circle drawing tools

Abstract

To increase a degree of freedom in choosing the radius of a circle to be drawn.SOLUTION: A circle drawing tool includes a band-shaped main body 110 having at least two writing instrument insertion holes 111, 112 arranged at a predetermined center-to-center distance, and a central axis member 120 provided so as to be positionable on a member to be drawn. The main body 110 is configured such that the writing instrument insertion holes 111, 112 can rotate around the central axis member 120 so as to draw a circle, and the central axis member 120 can be slid to a plurality of graduated positions, the plurality of graduated positions being set so as to have a predetermined distance from one of the writing instrument insertion holes 111, 112.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a circle drawing tool used for drawing a circle.

Background Art

[0002] As a ruler capable of drawing a circle, a shaft body is provided near the end of the ruler, a pen is inserted into any one of a plurality of through holes provided at a position at a predetermined distance from the shaft body, and the pen is rotated together with the ruler around the shaft body to draw a circle. A circle drawing tool is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By inserting the pen into the through hole selected from a plurality of through holes as described above, circles with various levels of radii can be drawn.

[0005] However, when it is possible to select the through hole into which the pen is inserted from a plurality of through holes as described above, the fineness of the selectable radius levels is restricted by the size of the through hole, that is, the thickness of the pen tip of the pen used. Specifically, for example, it is not possible to select a radius level finer than the diameter of the pen tip.

[0006] [[ID=四十三]] The present invention has been made in view of the above points, and aims to increase the degree of freedom in selecting the radius of the circle to be drawn.

Means for Solving the Problems

[0007] To achieve the above object, The present invention It is a circular drawing instrument, A strip-shaped main body having at least two writing instrument insertion holes provided at a predetermined distance between their centers, A central axis member positioned on the drawing target member, Equipped with, The main body is configured such that the writing instrument insertion hole can rotate around the central shaft member so as to trace a circle, and the central shaft member can be slid to multiple stepped positions. The above-mentioned multiple stepped positions are characterized in that they are set such that the distance from any of the above-mentioned writing instrument insertion holes is a predetermined distance.

[0008] This allows for setting multiple stepped positions such that the distance from any of the writing instrument insertion holes is a predetermined distance, thereby shifting the position of the central axis member even when the radius of the circle being drawn is close. This easily increases the degree of freedom in selecting the radius of the circle being drawn. [Effects of the Invention]

[0009] This invention allows for increased freedom in selecting the radius of the circle to be drawn. [Brief explanation of the drawing]

[0010] [Figure 1] This is a plan view showing the configuration of a circle drawing device. [Figure 2] This is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] This is a cross-sectional view taken along line III-III in Figure 1. [Figure 4] This is a cross-sectional view corresponding to Figure 3 of the modified example. [Modes for carrying out the invention]

[0011] Hereinafter, an example of a circular drawing tool used for marking out slab formwork and installing downlights at a construction site will be described in detail with reference to the drawings as an embodiment of the present invention. In the following embodiments, components having the same function as those in other embodiments will be denoted by the same or corresponding reference numerals and their description will be omitted.

[0012] (Embodiment 1) As shown in Figures 1 to 3, the circle drawing device 100 is configured such that a central axis member 120 is slidably provided on the main body 110 at multiple stepped positions.

[0013] The main body 110 is provided with writing instrument insertion holes 111 and 112, for example, at a center-to-center distance of 9.5 mm, into which an oil-based marker with a tip diameter of 9.5 mm or an architectural mechanical pencil with a tip diameter of 2.5 mm can be inserted. A slide groove 113 is also provided along the longitudinal direction of the main body 110. Multiple recesses 113a are provided on the inner circumference side of the slide groove 113, allowing the central shaft member 120 to be positioned in predetermined stepped positions, as will be described later. On the lower surface side of the main body 110, a lower surface recess 114 is provided in the area surrounding the slide groove 113, into which the large-diameter portion 121a of the central shaft member 120 fits. Furthermore, a protrusion 115 is provided near at least the writing instrument insertion holes 111 and 112 on the lower surface of the main body 110, and a step is provided around the writing instrument insertion holes 111 and 112 so that a gap is created between the circle drawing instrument 100 and the drawing target when the circle drawing instrument 100 is brought into contact with the drawing target.

[0014] The central shaft member 120 is assembled from a slide positioning member 121, a washer 122, a head 123, and a coil spring 124.

[0015] The slide positioning member 121 has a large-diameter portion 121a that fits into the lower surface recess 114 of the main body portion 110, an intermediate-diameter portion 121b that fits into the recess 113a of the slide groove 113, and a small-diameter portion 121c that is smaller in diameter than the minimum width of the slide groove 113. A rubber pad 125 is provided on the lower surface of the large-diameter portion 121a. Also, a nail hole 121d through which a nail to be driven into the drawing target member is inserted is provided at the center of the slide positioning member 121.

[0016] A washer 122 and a coil spring 124 are inserted between the upper surface side of the main body portion 110 and the head 123 in the small-diameter portion 121c of the slide positioning member 121, so that the slide positioning member 121 is pulled upward. Therefore, when the head 123 of the central shaft member 120 is pushed downward, the small-diameter portion 121c is smaller in diameter than the minimum width of the slide groove 113, so that the central shaft member 120 can slide in the longitudinal direction of the main body portion 110. Also, when the central shaft member 120 is pulled upward by the biasing force of the coil spring 124, the intermediate-diameter portion 121b fits into the recess 113a of the slide groove 113, and the central shaft member 120 is positioned at a predetermined stepped position.

[0017] In the above circular drawing instrument 100, for example, at a construction site, when drawing a circle corresponding to the outer diameter of the void as shown in (Table 1) with an oil-based marker having a pen tip diameter of 9.5 mm, the central shaft member 120 is positioned in the recess 113a at the scale position indicated as 50A to 300A, the head 123 is pressed against the drawing target member, and the pen tip of the above oil-based marker is inserted into the writing instrument insertion hole 111 to draw a circle. Similarly, when drawing a circle for making a hole for a downlight as shown in (Table 1) on the ceiling with a construction sharp pen having a pen tip diameter of 2.5 mm, the central shaft member 120 is positioned in the recess 113a at the scale position indicated as φ50 to φ250, the head 123 is pressed against the ceiling, and the core of the above construction sharp pen is inserted into the writing instrument insertion hole 112 to draw a circle.

[0018] Here, for the outer diameter of the void and the diameter of the hole for the downlight as described above, even if the nominal numbers are the same, the diameters or radii of the actual circles to be drawn are close to each other but not necessarily equal. Therefore, if the positions of the pen insertion holes 111 and 112 are set at the same position, it may be difficult to position the central axis member 120. However, in the above example, by arranging the positions of the pen insertion holes 111 and 112 at a center distance of 9.5 mm, as shown in conjunction with (Table 1), the distances from the central axis member 120 to the pen insertion hole 112 can be set at substantially equal intervals. Therefore, by appropriately setting the positions of the pen insertion holes, it can be easily made possible to draw circles with radii defined by two or more nominal values.

[0019] Also, by fixedly providing the pen insertion hole 112 as described above and making it possible to slide the position of the central axis member 120 to set the radius, it can also be easily made possible to set the steps of the radius to be finer than the diameter of the pen insertion hole 112.

[0020]

Table 1

[0021] (Embodiment 2) In order to set the center of the circle to be drawn, it is not limited to pressing or driving a nail into the drawing target member like the central axis member 120 described above, and a needle member may be provided so that it can be inserted into the drawing target member.

[0022] Specifically, the central shaft member 130 of Embodiment 2, as shown in Figure 4 for example, is composed of a slide positioning member 131 and a needle shaft 132, which corresponds to the slide positioning member 121 of Embodiment 1. More specifically, the slide positioning member 131 has a large diameter portion 131a, an intermediate diameter portion 131b, and a small diameter portion 131c, and a needle shaft insertion hole 131d is formed in the center. The large diameter portion 132a and the small diameter portion 132b of the needle shaft 132, to which the needle member 133 is attached, are fitted into the needle shaft insertion hole 131d so as to be able to move back and forth. A washer 122 and a coil spring 124 are fitted into the small diameter portion 131c of the slide positioning member 131, similar to the central shaft member 120. A head 123 is attached to the upper part of the needle shaft 132.

[0023] Even when such a central axis member 130 is used, it is still easy to increase the degree of freedom in setting the radius of the circle being drawn. [Explanation of Symbols]

[0024] 100 yen drawing device 110 Main body 111 Writing instrument insertion hole 112 Writing instrument insertion hole 113 Slide groove 113a Recess 114 Lower recess 115 Convex part 120 Central axis member 121 Slide positioning member 121a Large diameter section 121b Intermediate diameter section 121c Small diameter section 121d Nail hole 122 Washer 123 Head 124 Coil spring 125 Rubber Pads 130 Central axis member 131 Slide positioning member 131a Large diameter section 131b Intermediate diameter section 131c Small diameter section 131d Needle shaft insertion hole 132 Needle shaft 132a Large diameter section of the needle shaft 132b Needle shaft small diameter section 133 Needle member

Claims

1. A strip-shaped main body having at least two writing instrument insertion holes provided at a predetermined distance between their centers, A central axis member that is positioned on the drawing target member, Equipped with, The main body is configured such that the writing instrument insertion hole can rotate around the central shaft member so as to trace a circle, and the central shaft member can be slid to multiple stepped positions. The above-mentioned multiple stepped positions are set such that the distance from any of the above-mentioned writing instrument insertion holes is a predetermined distance. A circle drawing device characterized in that the maximum distance of the sliding range of the central axis member is set to be longer than the maximum distance between the centers of the at least two writing instrument insertion holes.

2. A circle drawing device according to claim 1, A circle drawing device characterized in that at least two of the above-mentioned writing instrument insertion holes have different diameters from each other.

3. A circle drawing device according to claim 2, A circle drawing device characterized in that the area around the writing instrument insertion hole in the main body is provided with a step so that a gap is created between the circle drawing device and the object to be drawn when the circle drawing device is brought into contact with the object to be drawn.

4. A circle drawing device according to claim 2, The circle drawing device is characterized in that the central axis member has at least one friction member that contacts the drawing target member when positioning it on the drawing target member, a needle member that is inserted into the drawing target member, and a nail hole through which a nail to be driven into the drawing target member is inserted.

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