Safe-T 45700 Bullseye Compass

Description
Like 2000.0160.06, this red and white plastic instrument combines a ruler, a protractor, and a compass. Unlike 2000.0160.06, this object is smaller, white instead of clear, and uses a slide instead of rows of holes for setting the radius of a circle. The semicircular (protractor) end is wider than the rectangular part of the instrument. It is marked in 15-degree increments in both directions, from 15 to 165 degrees, and divided to units of five degrees.
Inside the arc is a small rotating disc. The rectangular ruler has a groove down its center that carries a sliding red plastic piece with two holes in it. This piece can be set anywhere along the scales on the ruler, giving the distance from the center of the small disc. Placing a writing implement in one of the holes and rotating the ruler while keeping the disc fixed gives a circle of the radius set. One of the long edges has a ruler 12 centimeters long, divided to millimeters. The other edge has a five-inch ruler, divided to 16ths of an inch.
The back of the instrument is marked: U.S.Pat. # 5,615,485 (/) Other Pats. Pend. The back of the slide is marked: MADE (/) IN CHINA. The Bullseye Compass was introduced in 2000 and retailed for $1.99 in 2012.
References: Learning Resources online catalog (accessed October 22, 2012); Ho Chan, "Adjustable Compass with Ruler and Protractor" (U.S. Design Patent 411,959 issued July 13, 1999); J. Bruce Stoneberg, "Drawing Tool" (U.S. Patent 6,606,796 issued August 19, 2003); accession file.
Location
Currently not on view
date made
2000
maker
Safe-T Products, Inc.
place made
China
Associated Place
United States: Illinois, Bensenville
Physical Description
plastic (overall material)
Measurements
overall: .4 cm x 15 cm x 3.2 cm; 5/32 in x 5 29/32 in x 1 1/4 in
ID Number
2000.0160.08
accession number
2000.0160
catalog number
2000.0160.08
Credit Line
Gift of Extra Measures, Inc.
subject
Mathematics
Drawing Instruments
Protractor
Rule, Measuring
Education
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Dividers and Compasses
Data Source
National Museum of American History, Kenneth E. Behring Center

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