US Patent: 1,440,284
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Combination Rule
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Patentee:
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Otto L. Engstrom (exact or similar names) - South Bend, IN |
Manufacturer: |
Not known to have been produced |
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Patent Dates:
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Applied: |
Sep. 20, 1921 |
Granted: |
Dec. 26, 1922 |
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Ralph Brendler
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Description: |
This is a folding rule that does everything. It has a built in protractor and level vials to allow it to be used as a simple inclinometer, points to allow it to be used as dividers or calipers, and a caliper-style rule for measuring diameters. |
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