JPH0216719B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an ellipse delineator using thread.

Patent No. 956200 (Special Publication No. 53-37771 by the applicant)
Issue) describes an ellipse drawer that uses a thread to draw an ellipse according to the mathematical theorem that a trajectory with a constant sum of distances from two points is an ellipse. The problem solved in this patent is that, as is well known, when attempting to draw an ellipse using thread, the thread twists. To explain this with reference to Figure 1 of the drawings, for example, if you fix the two ends A and B of a single thread, then hang that thread around a pencil and rotate it, an intersection as shown at C will occur. be. The ellipse delineator of the invention disclosed in Patent No. 956200 (Japanese Patent Publication No. 53-37771) can be roughly explained as follows. An arm 4 is attached to the arm 4, and a wheel 5 is rotatably attached to one end of the arm.A friction member 3 that contacts the wheel 5 is attached to the edge of the lug plate 2, and its length is such that the wheel 5 rotates at least half a turn. A member 7 for holding a writing utensil, such as a tyoke, is attached to the arm 4, and the center of the writing utensil is placed just below the hook 6 for threading the thread attached to the wheel 5. A member 7 is arranged.

The ellipse delineator described in this patent No. 956200 can be used if the length of the friction member is equal to the circumference of the wheel 5.
It has the advantage that the thread will never twist no matter how many times it revolves around points A and B. However, this ellipse drawer has a complicated structure, increases manufacturing cost, and because the writing instrument is attached so that it is placed under the wheel 5, the writing instrument cannot be made very long. For example, if the yoke is too long, the error will increase if the axis 1 is tilted slightly from the perpendicular direction to the surface of the blackboard while drawing the ellipse.
If you shorten the yoke in an attempt to reduce the error caused by the tilt of the shaft, you will immediately have to replace the yoke. A similar problem occurs when holding something such as a pencil. Therefore, there was a need for an ellipse drawer that had a simple structure, could accommodate long writing instruments, and had fewer errors.

The object of the present invention is to provide an ellipse delineator that satisfies such wishes.

The present invention allows the thread to be twisted in one revolution by passing the thread in a specific direction through a hole that is made in a direction parallel to an axis perpendicular to the surface of the ellipse. It is based on the discovery that it is possible to draw an ellipse without This fact will now be explained using drawings.

FIG. 3 shows an ellipse drawer in which a lug plate with a hole 13 (the lower opening is designated by D and the upper opening by E) is rotatably mounted on the shaft 11. If the thread revolves in the direction indicated by arrow F, passing from point S to point P on the extension of AB→, but in such a way that thread AD passes below thread BE, then from A to lower opening D to upper Pass it through the hole so that it passes through opening E and goes to B. In this way, the thread will not twist even when it reaches point C.

Furthermore, if the direction of revolution is S→P→C as shown by the arrow below, and if the thread AD is to revolve below the thread BE, as shown in Figure 4, if When a thread is passed from the upper opening E to the lower opening D of the hole, after passing through P the thread is twisted as shown in C of the same figure. Therefore, for that revolution state, the thread is always at D as shown in Figure 3.
You must go from E to B through the hole.
If the revolution direction is in the direction F', which goes from the position S shown in Figure 3 to C through point P' on the extension of BA→, the thread from A goes from E to D through the hole. (exactly as shown at S in Figure 4). (thread
BD revolves under the thread AE).

For each revolution, there is only one way to pass the thread through the hole so that the thread does not get twisted during the revolution.

Due to this, it is possible to draw an ellipse without twisting the thread within one revolution.

When attaching writing utensils, please refer to Figures 5 and 6.
As shown in the figure, a hole is made near the hole 13 through which a writing instrument such as a pencil lead 14 can be passed diagonally, so that the pencil lead can be fixed so that the tip thereof is just below the hole 13. Therefore, if the tip of the pencil lead becomes worn out, you can press it one after another to get the lead out. In this way, a long writing instrument can be used so that when the tip wears out, the writing instrument only needs to be pushed out without having to be replaced every time. This is an advantage that cannot be obtained with Patent No. 956200.

Furthermore, since the distance between the hole through which the thread passes and the tip of the writing instrument can be reduced, errors caused by the inclination of the shaft can be reduced.
It can be made smaller than the one in No. 956200.

If errors are not a problem, the writing instrument may be held near and parallel to the hole 13 and perpendicular to the lug plate 12.

The writing instrument may be attached to the lug plate by any member other than the hole.

The lug plate may be very thin and the holes may be made of wire-like material.

The ellipse drawer of the present invention can be used not only to draw an ellipse with a writing instrument attached, but also to make an ellipse move by attaching something to any place on the ellipse drawer. You'll understand.

The ellipse delineator of Patent No. 95200 can prevent the thread from twisting no matter how many times it revolves. In contrast, the ellipse delineator of the present application can only make one revolution. However, if it is difficult to draw an ellipse, one revolution is usually sufficient. Therefore, the purpose can be fully achieved with the ellipse delineator of the present application.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a problem that occurs when drawing an ellipse using thread. FIG. 2 is a diagram of the ellipse delineator of Patent No. 956200. FIG. 3 is a diagram showing the principle of the ellipse delineator of the present invention. FIG. 4 is a diagram for explaining how to pass the thread through the hole. FIG. 5 is a perspective view of one embodiment of an ellipse delineator according to the present invention.
FIG. 6 is a side view, partially in section, of the ellipse delineator of FIG. 5. 11...shaft, 12...lug plate, 13...hole.

Claims (1)

[Claims] 1 A lug plate attached to an axis so as to be rotatable in a plane perpendicular to the axis, with a lug plate having a hole parallel to the axis, and a member attached to the lug plate to hold a writing instrument. and a member for supporting the tip so that the tip is directly below or near the hole.