US 4,899,449 AGranted

Drafting instrument

OwnerSimon Fouladianinventor

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Abstract

This invention relates to a novel design of a drafting instrument capable of assisting in the accurate drafting of arches, circles, as well as the measurement of angular relationships, and the like, whereby a base plate defines a circular opening having a cover plate symmetrically positioned about the perimeter of the opening formed in said base plate, there being symmetrically positioned about the center of the opening formed within the base plate a series of gear members such that upon the placement of a templet member whose dimensions are such as to have its perimeter come into mechanical contact with each of the gear members there is achieved a unique and novel means of positioning the templet member about the surface of a drawing while providing a mechanically accurate means to rotate said templet member about its center axis. By utilizing a templet 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.

Claims7

Dependent claims

A drafting instrument capable of centering a templet at a selected location above a planar surface without the necessity of having a center point pass through the center of said templet into said planar surface for purposes of maintaining the centering of said templet about said center point, wherein said drafting instrument comprises;

(a) A base plate defining a circular opening;
(b) Mounting member assemblies positioned about said circular opening formed through said base plate and structurally affixed to said base plate;
(c) A templet member capable of coming into direct mechanical contact with each of said mounting member assemblies about said templet's circular perimeter in a compressive mechanical interfit such that a force is applied from each of said mounting member assemblies against said templet such that the line of force from each of said mounting member assemblies intersect at a common point;
(d) A cover plate capable of being structurally affixed to said base plate whereby said cover plate and said base plate have cooperating means so as to cause a structural mounting between said base plate and said cover plate of said mounting member assemblies such that said cover plate causes a force to be applied from each of said mounting member assemblies against said templet member.

1 more element

Dependencies are inferred from the claim text.