发明授权
US4173829A Drafting instrument 失效
起草仪器

Drafting instrument
摘要:
A template for drawing accurately-positioned circular or straight lines regardless of the tip angle and diameter of the writing instrument used therewith has specially-shaped holes positioned at respectively different, predetermined spacings from a reference point, which may be an edge of the template or a pivot point on the template. Each hole has an elongated shape with opposed edges which converge at acute angles and which are equidistantly spaced from the line the hole is provided to draw. The holes may be arranged in parallel rows and spaced predetermined distances from either a single pivot point or multiple pivot points, or they may be in radial rows emanating from a single pivot point. The pivot point may comprise a pierced removable insert to accept wear from a pivot such as a tack, or it may be a hole in the template with a pivot point springably mounted adjacent the hole and lowerable thereinto.
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