JPS6411478B2 - - Google Patents

Description

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

Japanese Patent Publication No. 53-37771 by the present applicant describes an ellipse delineator that uses a thread to draw an ellipse according to the mathematical theorem that a locus with a constant sum of distances from two points is an ellipse. There is. 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 7 of the drawings, for example, if you fix both 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. . The invention disclosed in Japanese Patent Publication No. 53-37771 is designed to naturally untwist the thread while drawing an ellipse, but it is not possible to attach a long writing instrument, and errors due to the inclination of the main axis occur. Disadvantages include the large amount of thread inserted, the inability to shorten the distance between the threading hook and the tip of the writing instrument, resulting in large errors, and the need for a special structure, which increases manufacturing costs. has.

The object of the present invention is to provide an ellipse delineator that eliminates such drawbacks.

The present invention will be explained using the drawings.

In FIG. 1, an elongated lug plate 2, which is approximately pentagonal in shape and tapered at one end, is rotatably mounted near one end of the main shaft 1, along the edge opposite to the tapered side. Two fulcrum members, such as studs or ball bearings, are mounted spaced apart 3, 3'. At the tapered end, a writing instrument 4, such as a pen or pencil lead, is inserted into a writing instrument support structure 13, such as a hole and a fixing material (the hole may be cut in one place and formed into a groove). Therefore, it is fixed diagonally to the lug plate. The writing instrument supporting structure is configured such that the length of the end of the writing instrument protruding below the lug plate can be adjusted. A rotating shaft 6 having a threading ring 5 at one end is rotatably supported by a support 7 fixed to a lug plate. At one end of the rotating shaft 6 on the opposite side from the threading ring 5, a rotating shaft end annular member 8, such as a gear or wheel with a slightly larger diameter, is attached. A fan-shaped arm member 10 is attached to the end of the main shaft 1 protruding below the lug plate, and the fan-shaped arm member 10 engages with or comes into contact with the annular member at the end of the rotating shaft, and the arc of the fan-shaped arm member The length is sufficient for the fan-shaped arm member to rotate while contacting the annular member at the end of the rotating shaft and to rotate the annular member half a rotation when the main shaft is rotated with respect to the lug plate.

When operating the ellipse drawer with the structure shown in Figure 1, as shown in Figure 3, properly support both ends of the thread threaded through the threading ring, and rotate the thread A, B while pulling it so that it does not slacken. . The lug plate rotates relative to the main axis, and when the ellipse delineator comes to a nearby point on the extension line, for example, point C, the fan-shaped member begins to contact the annular member at the end of the rotating shaft, and the ellipse delineator comes into contact with the annular member at the end of the rotating shaft, and the ellipse delineator reaches a point near the extension line of C'. When you reach the point, leave it. As a result, the rotation axis rotates by half a rotation,
The twist in the thread is eliminated.

In the ellipse delineator having the structure shown in FIG. 1, the two fulcrum members 3, 3' and the tip of the writing instrument 4 constitute three points that determine one plane, thereby making it possible to prevent the main axis from tilting. Furthermore, the threading ring 5 and the tip of the writing instrument can be kept very close together, making it possible to reduce errors. Additionally, this ellipse drawer allows the use of long pencil lead.

Another embodiment of the present invention is shown in FIGS. 4 and 5. In this ellipse drawer, compared to the lug plate shown in FIG. A rotating shaft 6 having a through ring 5 is rotatably supported by a support 7. The fan-shaped arm member 10 rotating together with the main shaft under the lug plate can be seen through the cut-out portion of the lug plate.

As can be seen from the above embodiments, the rotating shaft may be attached to the top, side, or bottom of the lug plate.

The lug plate does not need to be flat; for example, as shown in Figure 6, the lug plate has a U-shape with the center area open downward, and
The arm member may be in a higher position.

When using a thread support device in which points A and B supporting both ends of the thread are supported upwardly from the plane of the paper by long rods (for example, such a thread support device is 60-76397, JP-A-60-997), so that the main shaft is bent slightly above the lug plate so that the ellipse can be passed under the rod. It's okay to be. For example, as shown in Figure 8, the main shaft passes through the lug plate 1.
Only 5 is cylindrical, and the others are square prisms or plates, and may be bent by hinges 14. As shown in FIG. 9, a pin 17 is passed through the tip of a prismatic main shaft upper part 16 whose opposing sides are triangular at one end, and the pin has a portion 15 through which the pin passes downward through the lug plate. It may have a structure in which it is supported by the lower part of the main shaft 18 and can be bent to either the left or right. In the case of such a bendable main shaft, a structure for holding the main shaft straight may be provided. For example, the ring 19 can be moved up and down by the projection 20, and if it is lowered, the notch 21 will be located at the upper end of the lower part of the main shaft and can prevent bending of the main shaft. When a structure such as a pivot is used as a bending mechanism, it is necessary to provide a structure that can prevent relative rotation of the upper and lower parts of the main shaft and also prevent bending thereof.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a specific example of an ellipse delineator according to the present invention. FIG. 2 is a side view of the specific example shown in FIG. FIG. 3 is a diagram for explaining how to operate the ellipse delineator of the present invention. Fourth
The figure is a plan view of another embodiment of the ellipse delineator according to the invention. FIG. 5 is a slightly enlarged front view of the specific example shown in FIG. 4 with some parts removed. FIG. 6 is a partial side view showing one embodiment of the lug plate. Figure 7 is a diagram to show the problem that occurs when drawing an ellipse using thread. FIG. 8 is a schematic perspective view of a specific example of a bendable main shaft. FIG. 9 is a schematic perspective view of another example of the bendable main shaft. DESCRIPTION OF SYMBOLS 1... Main shaft, 2... Lug plate, 5... Threading ring, 6... Rotating shaft, 7... Support body, 8... Rotating shaft end annular member, 1
0... Arm member, 13... Writing instrument support structure, 3, 3'
...Fulcrum member.

Claims (1)

[Claims] 1 A main shaft, a lug plate rotatably attached near one end of the main shaft so that it can rotate in a plane perpendicular to the axis, and a support fixed to the lug plate to allow the lug plate to rotate. A rotating shaft supported in parallel, with a threading ring at one end and an annular member at the other end for rotating the rotating shaft, with a part of its outer circumference below the bottom surface of the lug plate. It has a rotating shaft for positioning the threading ring outward from one end of the lug plate, and a writing utensil is placed at one end of the lug plate near the position of the threading ring against the lug plate. a writing instrument support structure for holding the writing instrument diagonally so that the tip of the writing instrument is directly below the threading ring;
two fulcrum members spaced apart from each other near the edge of the lug plate opposite to the side where the threading ring is located; and the annular member fixed to the end of the main shaft protruding below the lug plate. An ellipse delineator consisting of an arm member for rotating the member.