Protractor and ruler combination

• US 20050155234A1
• Filed: 01/21/2004
• Published: 07/21/2005
• Est. Priority Date: 01/21/2004
• Status: Active Grant

• Current Assignee: Kun-Li Xieh
• Original Assignee: Kun-Li Xieh
• Inventors: Xieh, Kun-Li
• Granted Patent: US 6,978,550 B2
• Time in Patent Office: Days
• US Class Current: 33/27.30
• CPC Class Codes: B43L 13/002 Angle intersecting devices
• CPC Class Codes: B43L 7/10 Plural straightedges relatively movable
• CPC Class Codes: G01B 3/04 rigid
• CPC Class Codes: G01B 3/563 Protractors for use in geodesy G01C1/00; protractor heads for drawing machines B43L13/08

Abstract

A protractor and ruler combination includes a main ruler having a side formed with a protractor, a secondary ruler rotatably mounted on the main ruler, and an auxiliary ruler having a side secured on the secondary ruler, so that the secondary ruler is moved in concert with the auxiliary ruler on the protractor of the main ruler. Thus, the auxiliary ruler is moved relative to the main ruler, and the secondary ruler is moved in concert with the auxiliary ruler on the protractor of the main ruler, so that the included angle between the ruler section of the main ruler and the ruler section of the auxiliary ruler is measured exactly.

Claims

1. A protractor and ruler combination, comprising a main ruler, a secondary ruler, and an auxiliary ruler, wherein:

the main ruler has a first side integrally formed with a protractor having a plurality scales and a center;

the secondary ruler is semi-circular shaped, rotatably and concentrically mounted at the center on the protractor of the main ruler and has a plurality reading scales and a center aligning to the center of the protractor on the main ruler; and

the auxiliary ruler is rotatably mounted at the center on the secondary ruler and has a first side combined with the secondary ruler, wherein the secondary ruler is clamped between the main ruler and the auxiliary ruler and moved in concert with the auxiliary ruler on the protractor of the main ruler.

2. The protractor and ruler combination in accordance with claim 1, wherein the main ruler has a second side formed with a ruler section having a plurality scales.

3. The protractor and ruler combination in accordance with claim 2, wherein the ruler section of the main ruler has a distal end formed with a fixing hole, and the protractor and ruler combination further comprises a flattened support member pivotally mounted on the ruler section of the main ruler, and a pivot shaft extended through an end of the support member and fixed in the fixing hole of the ruler section.

5. The protractor and ruler combination in accordance with claim 1, wherein the protractor of the main ruler has a through hole formed at the center and has a periphery formed with a guide slot, the secondary ruler has a through hole formed at the center of the secondary ruler to align with the through hole of the protractor and has a periphery formed with a through bore aligning with the guide slot of the protractor, the first side of the auxiliary ruler is formed with a through hole aligning with the through hole of the secondary ruler and a through bore aligning with the through bore of the secondary ruler, and the protrctor and ruler combination further comprises a pivot pin extended through the through hole of the auxiliary ruler, the through hole of the secondary ruler and the through hole of the protractor, and a snap member secured on a distal end of the pivot pin.

6. The protractor and ruler combination in accordance with claim 5, further comprising a screw member extended through the guide slot of the protractor, the through bore of the secondary ruler and the through bore of the auxiliary ruler, and a nut screwed on the screw member and rested on the first side of the auxiliary ruler.

7. The protractor and ruler combination in accordance with claim 5, wherein the guide slot is arc-shaped.

8. The protractor and ruler combination in accordance with claim 1, wherein the auxiliary ruler has a second side formed with a ruler section having a plurality scales.

9. The protractor and ruler combination in accordance with claim 1, further comprising an anti-skid pad mounted on a face of the auxiliary ruler.

10. The protractor and ruler combination in accordance with claim 9, wherein the anti-skid pad separates the auxiliary ruler from the main ruler.

11. The protractor and ruler combination in accordance with claim 9, wherein the anti-skid pad is located beside the secondary ruler and has an end rested on a periphery of the secondary ruler.

12. The protractor and ruler combination in accordance with claim 1, wherein the reading scales of the secondary ruler have sizes determined according to an inner diameter of the scales of the protractor, and the secondary ruler has a periphery located inside of the scales of the protractor.

13. The protractor and ruler combination in accordance with claim 12, wherein the periphery of the secondary ruler and the inner diameter of the scales of the protractor form a circle.

4. (canceled)