| 摘要 |
<p>The drafting instrument (10) capable of assisting in the accurate drafting of arches, circles, as well as the measurement of angular relationships, and the like, has a base plate (11) defining a circular opening and a cover plate (12) symmetrically positioned about the perimeter of the opening formed in said base plate (11). Symmetrically positioned about the center of the opening formed within the base plate (11) are a series of mounting members (13,14,15) such that upon the placement of a templet member (16) whose dimensions are such as to have its perimeter come into mechanical contact with each of the mounting members (13,14,15) there is achieved a unique and novel means of positioning the templet member (16) about the surface of a drawing while providing a mechancially accurate means to rotate said templet member (16) about its center axis (0). By utilizing a templet (16) having pre-conceived openings formed through its surface capable of receiving the point of a pencil or pen, there is achieved a means to accurately draw upon a surface arches, circles, and the like, as well as to achieve the measuring of angular relationships.</p> |
