SU47085A1 - Circle Drawer - Google Patents

Description

The invention relates to devices for drawing circles or parts of their various radii that do not have a physical center of rotation — one constant set of parts. A less complicated device in its design consists of a rod, through which, the axes of two forks carrying sharp rollers pass through the holes. On the side of the frame, a special leg with a roller is fixed, forming the third point of support of the device. Both rollers are automatically installed symmetrically with respect to the legs by means of leads rigidly fastened to the rollers and hinged to the rocker arm. In the cartridge placed in the rod between the forks, there is a pencil which, when the instrument is rolled over the paper, draws an arc whose radius depends on the angle formed by the directions of the geometric axes of the rollers.

In FIG. 1-3 depict a general view of the device (in three projections).

The proposed device consists of a rod /, through the holes at the ends of which axles 2 of forks 3 are passed, carrying sharp rollers 4, freely rotating on axles 5. Axes 2 and 7, hingedly attached to the upper arm 8, are attached to the upper ends of axes 2 turn b and 7 leads at equal angles. In leash 7

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The micrometer screw | P, which passes through the JO nut, abuts, while the leash 6 is fastened to the rod / spring / 7. Through the middle of the rod / cartridge 12 for a pencil or pen / 5 freely sliding in the rod / and slightly pressed on top by a spring 4. To the rod / leg 15 is attached, carrying at its end the support roller 16 and the arrow / 7. Two rollers 4 and roller 16 give the device three points of support, thereby ensuring its stability on the drawing board. Thus, all the angular position of the leash 7 corresponds to one definite, symmetrical to it, position of the leash b. Therefore, the rollers 4, rotated from the leads b and 7 on the axis 2 together with the forks 3, are always installed symmetrically with each other with the axis of symmetry in the form of the axis of the leg 75 or, equivalently, the line connecting the writing point with the tip of the arrow / 7. When the instrument is rolling on paper, the instantaneous direction of movement of each of the rollers 4 coincides with the direction of the tangent, at the roller’s point of contact with the paper, at the circle whose center lies at the intersection of the geometric axes of the rollers 4. Therefore, each angular position of the rollers 4 corresponds to a certain radius of the circle, which they cat; the writing tip of J3 draws on paper a circle of radius 1 // - a, where R is the rolling radius of the rollers 4 and a is half the distance between the axes 2, that is, and for a writing tip, the radius of the circle drawn by him from the angular position of the rollers 4. If there is a direction in the drawing of the radius of the circle to be drawn and a point at the end thereof belonging to this circle, the device is installed as follows. The tip 13 is slightly raised above the surface of the paper, secured by a screw 18 and installed above the point, the whole device is rotated in such a way that the tip of the arrow / 7 falls in the direction of the radius. Then the screw 18 is released, the tip 13 is pressed against the paper by the forces of its weight and the spring 14 and the circle is drawn on the paper by free movement of the device.

The installation of the desired radius is performed by rotating the head 19 of the micrometer screw I and the nut hub 10 is graduated in portions of the radius, or the calibration of a conventional micrometer is used and the device is provided with a table for translating the micrometer readings into radius lengths.

The subject matter of the invention.

A device for drawing the circumference of 4ness or parts of their various radii, which does not have a physical center of rotation, using a micrometer screw, characterized in that, for the purpose of automatically symmetrical installation of the rollers 4, leads 6 and 7 are used, each of which is rigidly connected to the axis of the fork. his roller 4 and the ball Nirno with a rocker about.

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