JPS6325196Y2 - - Google Patents

Description

[Detailed description of the invention] Conventionally, when drawing a circle with a compass, the center needle of the compass leaves a mark on paper, drawing boards, etc. Another drawback was that it was extremely difficult to draw a circle on a metal blackboard.

The present invention has been proposed in order to eliminate such drawbacks, and includes a permanent magnet piece 2 on the bottom surface of an inverted bowl-shaped adsorption piece 1 made of an elastic material, and a center needle of a compass inserted in the center on the top surface. The present invention relates to a circle drawing tool characterized in that positioning plates 4 each having a concave hole 3 are laminated.

In the illustrated embodiment, the positioning plate 4
is made of non-magnetic metal, synthetic resin, etc., and is provided with a cross standard line 5 having a pair of diameters orthogonal to each other passing through the recess 3 to facilitate aiming at the position of the center needle of the compass.

Since the present invention is constructed as described above, the entire circle drawing tool is positioned so that the concave hole 3 of the positioning plate 4 coincides with the center of the circle relative to the object on which the circle is to be drawn. When the drawing tool is crimped onto the object, the inside of the inverted bowl-shaped suction piece 1 made of an elastic material such as rubber becomes a vacuum state, and the suction piece 1 is adsorbed to the object, and at the same time If it is a magnetic material such as a metal blackboard, a permanent magnet piece 2 layered on the bottom surface of the inverted bowl-shaped adsorption piece 1 is used.
is attracted, and thus the circular drawing tool of the present invention is fixed in a predetermined position.

Thereafter, the center needle of a compass is inserted into the recess 3 provided at the center of the positioning plate 4 layered on the upper surface of the bent bowl-shaped suction piece 1, and a circle is drawn using the compass. Therefore, the center needle of the compass is inserted into the recess 3 of the positioning plate 4 and is not directly inserted into the object, so it does not leave any scars on the object, and even when drawing a circle on a metal blackboard,
Using the circle drawing tool fixed to the same blackboard as described above, insert the center needle of a compass into the concave hole 3 of the positioning plate 4 and easily draw it with a compass in almost the same way as on a regular piece of paper. It is something that can draw a circle.

Furthermore, according to the present invention, as described above, when the object is made of magnetic metal such as a metal blackboard, the permanent magnet piece 2 and the tilted bowl-shaped adsorption piece 1 are used to hold a non-magnetic material such as a piece of paper. In this case, the circle drawing tool is fixed to the object by the inverted bowl-shaped suction piece 1, and it is possible to draw circles on various objects.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the circle drawing tool according to the present invention, and FIG. 2 is a longitudinal sectional view thereof. 1...Tumbled bowl-shaped adsorption piece, 2...Permanent magnet piece, 3
...Concave cavity for inserting the center needle of the compass, 4...Positioning plate.

Claims (1)

[Scope of utility model registration request] A permanent magnet piece 2 is layered on the bottom surface of an inverted bowl-shaped adsorption piece 1 made of an elastic material, and a positioning plate 4 having a concave hole 3 for inserting the center needle of a compass in the center is layered on the top surface. A circle drawing tool.