JP4686591B2 - Ruler to draw a circle - Google Patents

Description

  The present invention relates to a ruler for drawing a circle.

Conventional techniques for drawing a circle include a compass, a template, and a ruler. Compass is time-consuming to adjust the compass to the length of the radius of the circle you want to draw, the center position shifts when drawing a circle, and the drawing line rises because the paper surface floats up and draws an accurate circle quickly It was difficult. It was also dangerous because it was equipped with a needle. There were no templates with the size of the desired circle, or the center of the circle could not be aligned. On the other hand, a ruler for drawing a circle is provided with a plurality of small holes at different distances from the center of the disk surrounded by an outer frame and held rotatably, and the core of a writing instrument such as a mechanical pencil is inserted into these small holes. A circle is drawn on the paper surface while rotating (see Patent Document 1, Patent Document 2, and Patent Document 3). However, there was a fundamental problem that the disk did not rotate smoothly.

In order to solve this problem, a bearing ball is provided to reduce the contact resistance between the outer frame and the disk (see Patent Document 4 and Patent Document 5), but this alone does not solve the fundamental problem. In view of this, there is one in which a rotational moment is provided by providing a rotation axis at the center of the disk and fixing the center position of rotation (Patent Document 6). This allowed the disk to rotate smoothly. However, by providing a rotation axis at the center of the disk, it is not possible to firmly hold the paper surface with the outer frame, and the same problem as the compass that the paper surface rises when drawing a circle and the drawn lines shift It was decided to do.

Utility Kaihei 5-60894 Utility Kaihei 6-63386 JP-A-7-314989 Utility model registration No. 3054958 Japanese Patent Laid-Open No. 2001-30585 JP 2006-187865 A

The present invention comprises an outer frame and a rotating body such as a disk that is surrounded by the outer frame and is rotatably supported, and a ruler that draws a circle while rotating the rotating body such as a disk. A bearing ball is provided between the outer frame and the rotating body such as a disk to reduce contact resistance, and a rotating shaft is provided at the center of the rotating body such as a disk so that the center position of the rotation is fixed. In the drawing ruler, it is a problem to solve the problem that the drawing surface shifts due to the paper surface floating when drawing a circle, because the rotation axis is provided so that the paper frame can not be firmly pressed by the outer frame. .

A concave groove is provided along the periphery on the upper surface of the peripheral part of a rotating body such as a disk, and a plurality of bearing balls are inserted into the groove, and the upper part of the outer frame faces downward so that these bearing balls can be fitted. A concave groove is provided along the periphery. On the other hand, a paper presser of an elastic body such as a sponge body (sponge) or rubber is provided below the bottom of the outer frame. When a rotating body such as a disk surrounded by an outer frame and held rotatably is placed on the paper surface, the rotating body such as a disk surrounded by the outer frame is on the bottom of the outer frame. The bearing ball and the bottom of the concave groove provided at the top of the outer frame do not contact each other, and the tip of the rotating shaft provided at the center of the rotating body such as a disk does not contact the paper surface. It is configured so that a large gap (play) is possible. By these, the paper frame is pressed down firmly by hand by pressing down the outer frame from the top, and the paper presser shrinks, so the tip of the rotating shaft comes into contact with the paper surface. Since the outer frame bottom and the rotating body riding on the outer frame bottom are separated from each other, a gap is formed between the two. Next, the bearing ball and the bottom of the concave groove provided on the outer frame come into contact with each other. The pressed force is transmitted to a rotating body such as a disk via a bearing ball, the force is transmitted to the rotating shaft, and the tip of the rotating shaft presses the paper surface with a pin point so that the center position of the drawn circle can be fixed.

By pressing the outer frame down from the top, the paper surface is firmly held by the paper presser, which solves the problem that the paper surface rises when drawing a circle, causing the line to shift, and the tip of the rotating shaft is pinpointed. Since the center of the circle to be drawn is fixed by pressing the paper surface, a moment of force works, and a rotating body such as a disk rotates smoothly like a top. By these, circles of various sizes from large circles to small circles can be drawn easily, quickly and accurately. Therefore, no compass or template is required.

Hereinafter, embodiments of the present invention will be described based on examples with reference to FIGS. FIG. 1 is a plan view of this ruler and a cross-sectional view taken along the line AA. In FIG. 1, this ruler has many small holes at different distances from the center of the disk 1, and the core of a writing instrument such as a mechanical pencil is inserted into these small holes, and a circle is drawn on the paper surface while rotating the disk 1. is there. The disk 1 has a rotating shaft 2 at the center thereof, and a groove 3 for receiving a plurality of bearing balls 4 on the upper surface of the periphery thereof. The disk 1 is surrounded by an outer frame 5 and an outer frame bottom 6. The outer frame 5 is doughnut-shaped and has a side surface on the outer periphery thereof, and is shaped to cover the disk 1 from above. The outer frame bottom 6 is also a donut shape and is fixed to the lower side of the outer frame 5. The paper presser 7 is also a donut shape and is fixed to the lower side of the outer frame bottom 6. In addition, a concave groove 8 is provided downward along the periphery of the outer frame 5 so that the bearing ball 4 fits just below the upper part of the outer frame 5. The disk 1 and the rotating shaft 2 are made of a transparent plastic so that the paper surface can be seen when drawing a circle. Further, the paper presser 7 is made of an elastic body such as a sponge body (sponge) or rubber that expands and contracts. The disk 1 is provided with a small hole so that the radius of the circle can be drawn in units of 1 mm. However, since it can be drawn in units of 0.5 mm, a precise circle can be drawn. Further, the size of the disk 1 can be drawn up to a radius of 50 mm, but this size can also be freely determined.

FIG. 2 is a partially enlarged view of the AA cross-sectional view in FIG. FIG. 2A is a diagram illustrating a state in which the ruler is placed on the paper surface, and is a state before the outer frame is pushed down from the top by hand. FIG. 2B is a diagram illustrating a state after the ruler is placed on the paper surface and the outer frame is pushed down from above by hand. In FIG. 2A, the disk 1 is on the outer frame bottom 6, and is between the bearing ball 4 and the bottom of the concave groove 8 provided downward on the upper surface of the outer frame 5. There is a slight gap (play) α. Further, there is a gap (play) β between the tip of the rotating shaft 2 and the paper surface so that the tip of the rotating shaft 2 and the paper surface do not come into contact with each other. When the top is moved, the tip of the rotating shaft 2 moves smoothly without being caught on the paper surface.

In FIG. 2 (b), when the outer frame is pushed down from the top by hand, the paper presser 7 firmly holds the paper surface, and the paper presser 7 is made of a sponge so that it shrinks. The gap (play) β between them disappears and both sides come into contact. By further pressing down, the disk 1 that has been on the outer frame bottom 6 is separated from the outer frame bottom 6 and a gap is formed between the disk 1 and the outer frame bottom 6, while the bearing ball 4 and the outer frame 5. There is no gap (play) α between the bottom of the concave groove 8 provided in the contact and both contact. Further, the force pushed down by the hand is transmitted to the disk 1 through the bearing ball 4, and the force is transmitted to the rotating shaft 2, and the tip of the rotating shaft 2 pushes the paper surface at a pinpoint, and bites into the paper surface to form γ. With these series of actions, the paper surface is firmly held down, the center position of the circle is fixed, and the disc 1 and the outer frame bottom 6 do not come into contact with each other, so the bearing works effectively and the disc 1 rotates smoothly. Will be able to draw quickly and accurately. It is not necessary to sharpen the tip of the rotary shaft 2 so that the center position of the circle can be fixed by pressing it against the paper surface. For this reason, it is not so likely to make a hole in the paper surface like a compass needle. . For this reason, it is not very dangerous for children. The gaps (plays) α, β, and bite γ need only be about 0.5 mm to 1 mm, so the paper presser 7 only needs to be able to shrink about 3 mm at the maximum.

FIG. 3 is a plan view of the disk 1 and a sectional view taken along the line AA. A rotating shaft 2 is provided at the center of the disk 1, and a groove 3 for receiving a bearing ball 4 is provided on the upper surface of the peripheral part of the disk 1. The disk 1 and the rotating shaft 2 are made of transparent plastic.

FIG. 4 is a plan view and a front view of the outer frame 5, the outer frame bottom 6, and the paper presser 7. An outer frame bottom 6 is fixed to the lower side of the outer frame 5, and a paper presser 7 is fixed to the lower side of the outer frame bottom 6. The paper presser 7 is made of an elastic body such as a sponge body (sponge) or rubber that expands and contracts.

The top view and AA sectional drawing of the ruler which draws the circle which concerns on the Example of this invention Partial enlarged view of AA sectional view in FIG. Plan view and AA sectional view of the disk 1 Plan view and front view of outer frame 5, outer frame bottom 6 and paper presser 7

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Disc 2 Rotating shaft 3 Recessed groove provided in disk 4 Bearing ball 5 Outer frame 6 Outer frame bottom 7 Paper presser 8 Recessed groove provided in outer frame α Clearance between bearing ball and recessed groove provided in outer frame (play)
β Clearance between paper surface and tip of rotating shaft (play)
Gamma Rotating shaft bites into the paper

Claims (2)

The outer frame and a rotating body surrounded by the outer frame and rotatably held, provided with a plurality of small holes at different distances from the center of the rotating body, and the core of the writing instrument is inserted into the small hole , In a ruler that draws a circle with a rotation axis at the center of the rotating body, while providing a bearing ball between the outer frame and the rotating body on a ruler that draws a circle on the paper while rotating,
A concave groove is provided along the periphery above the periphery of the rotating body, a plurality of bearing balls are inserted into the groove, and a concave groove is formed downward on the upper lower side of the outer frame so that the bearing balls are fitted. Is provided along the periphery, while a paper presser of a sponge body (sponge) is provided below the bottom of the outer frame, and when the rotating body surrounded by the outer frame is placed on the paper surface, The rotating body is put on the bottom of the outer frame, the bearing ball and the bottom of the concave groove provided in the outer frame are not in contact with each other, and the rotating body is provided at the center of the rotating body. The tip of the rotating shaft is not in contact with the paper surface, and each has a slight gap (play).
The paper frame is pressed down by hand by pushing down the outer frame from above, and the paper presser shrinks, so that the tip of the rotating shaft comes into contact with the paper surface, and the rotary body is relatively lifted by further pressing down. Therefore, the rotating body riding on the bottom part of the outer frame is separated from the bottom part of the outer frame, and a gap is formed between the rotating body and the bottom part of the outer frame, while the bearing ball and the outer frame are provided. The bottom of the concave groove comes into contact, and the force pushed down by the hand is transmitted to the rotating body via the bearing ball, further transmitted to the rotating shaft, and the tip of the rotating shaft presses the paper surface at a pinpoint and draws. A ruler that draws a circle characterized by the ability to fix the center position of the circle. The ruler for drawing a circle according to claim 1, wherein the paper presser is made of an elastic body such as rubber.