Back to results
US 4,731,933 AGranted
Protractor-chalkline
OwnerCharles D. Copeinventor
Life of this patent
Estimating the term…
Abstract
A chalkline device situated on a protractor in such a manner which permits the chalkline string to extend from the centerpoint of the protractor's radius past the degree markings on the protractor. By placing the centerpoint side of the protractor on any straight surface and extending the chalkline string past the degree markings any angle measurement can, by the chalkline string, be determined and marked in the same process. The chalkline string serves as both the hand of a dial and a medium for conveyance of the chalk to the surface being marked or measured.
Claims6
An angle marking device comprising:
- a semi-circular protractor (2) having a first top side, a second bottom side, a front curved edge and a rear straight edge,
- the first top side of said semi-circular protractor (2) having a compartment means (4) mounted thereon,
- said compartment means (4) having a line and spool (5) contained therein and said compartment means being adapted to contain a powder chalk marking substance therein,
- said compartment means (4) having an aperture means at the rear thereof for running said line therethrough,
- wherein said semi-circular protractor (2) has an edge (8B) extending at right angles from said rear straight edge and wherein a slot (6) is formed at substantially the middle portion of said edge (8B) to provide means whereby said line may be extended under said semi-circular protractor (2) for use as an angle marking device.
2 more elements
Dependencies are inferred from the claim text.