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US 4,530,156 AGranted
Infinite radius circle drawing instrument
OwnerJohn S. Kettlestringsinventor
Life of this patent
Estimating the term…
Abstract
A device for drawing circles which allows for an infinitely adjustable radius within a given range is provided by the use of a rotatable disk having an access hole therethrough offset from a center point of, but carried on a disk rotatable with respect to a fixed sheet member. The larger disk is freely rotatable and the disk with the access hole is prevented from rotating while the circle is being drawn.
Claims15
A device for drawing circles comprising:
- a sheet member for laying on a drawing surface;
- a first member rotatably held within an opening in said sheet member, freely rotatable about a center point;
- a second member rotatably held within an opening in said first member, offset from said center point;
- at least one hole through said second member to accomodate a marking point;
- and
- means for restraining said second member against rotation when
- said marking point is inserted in said hole and rotated about said center point.
4 more elements
A device for drawing circles comprising:
- a sheet-form member having a planar lower surface;
- a first circular hole formed in said sheet-form member having a given diameter;
- a first circular disk having a diameter less than said diameter of said hole and having a marked center point;
- means associated with said hole to rotatably retain said disk within said hole such that a bottom surface of said disk is elevated above said lower surface of said sheet-form member;
- a second circular hole formed in said circular disk, offset from said center point and having a given diameter;
- a second circular disk having a diameter less than said diameter of said second hole;
- means associated with said second hole and said second disk to rotatably retain said second disk within said second hole such that a given amount of torque is required to rotate said second disk;
- said second disk having at least one hole therethrough to accomodate a marking point;
- whereby, rotation of said marking point about said center point will cause rotation of said first disk relative to said sheet-form member and will generate less than said given amount of torque required to rotate said second disk relative to said first disk.
6 more elements
A device for drawing circles comprising:
- a sheet member for laying on a drawing surface;
- said sheet member having a circular hole therein;
- a first disk member captured in said hole for free rotation with respect to said sheet member;
- said disk member having a circular hole therein offset from a center point of said disk;
- a second disk member captured in said second hole for rotation with respect to said first disk member upon the application of a sufficient torque;
- said second disk member having at least one hole therethrough for accomodating a drawing point;
- whereby rotation of said second disk relative to said first disk provides infinite adjustment of the distance between said second disk hole and said center point, and rotation of said first disk relative to said sheet member causes said second disk hole to define a circle about said center point.
4 more elements
Dependencies are inferred from the claim text.