If you find a patent number or patent date by this manufacturer that is not on this
list, please contact the Site Historian.
Key to Links for Patent Information
USPTO = U.S. Patent Office .
Images of the actual patent can be viewed on the U.S. Patent Office web site but
a special TIFF viewer must be installed with your browser in order properly work.
More information on how to configure your computer to view these patents can be
found at TIFF image Viewers
for Patent Images.
DATAMP = Directory of American Tool And
Machinery Patents . A sister site to VintageMachinery.org with information
on patents related to machinery and tools. A much easier user interface than the
USPTO's for finding information on machinery patents.
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2,091,995
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Sep. 07, 1937
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Hardness testing device
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Frederick Knoop |
Washington, DC |
See patent 2,722,853 for an improvement to this patent. A 1957 brochure for the Tukon Tester from the Wilson Instrument Division of the American Chain & Cable Co., Inc., mentions "The Knoop Indenter (U. S. Patent No. 201995 under which we hold license)..." |
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2,722,831
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Nov. 08, 1955
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Hardness testers
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Charles W. Smith |
Stratford, CT |
This patent number was seen in a sales brochure for the "Tukon Tester" from the Wilson Mechanical Instrument Division, American Chain & Cable Co., Inc. The patent specification notes, "In U. S. Patent No. 2,091,995 there is described an indenter which is in the form of a pyramid with two greatly elongated edges, which produces as impression, as viewed with the microscope, of a rhombus with one diagonal much longer than the other..." This present patent provides improvements on that predecessor patent. One improvement is intended to reduce vibration during contact of specimen and indenter, and another improvement is to place the specimen in proper position for testing by the act of focusing the microscope on the specimen. |