US Patent: 2,959,087
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| Precision optical measuring device
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Patentee:
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| William Palmer Strickland, Jr. (exact or similar names) - Chicago, IL |
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Patent Dates:
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| Applied: |
Oct. 31, 1956 |
| Granted: |
Nov. 08, 1960 |
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Jeff Joslin
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Description: |
| This device is "an optical reader and vernier which operates in conjunction with a linear scale when mounted...on a machine tool bed to permit the easy and accurate measurement of the travel of the bed."This patent covers the "Vernac" optical measuring accessory, used on milling machines, surface grinders, and other machine tools with a moving bed. A high-precision 25-inch scale is fixed to the machine table and a strong magnifying lens projects an image of the scale onto a "mask" having a viewing window, a sighting slit, and a vernier window. A vernier is rotated to align markings in the sighting slit. The vernier-window reading is then added to the direct scale reading shown in the viewing window. As a further complication to accomodate machines with travel greater than 25 inches, an index bar with holes at 20-inch spacings is used to set a range, with the ranges overlapping by a few inches. Thus, determining a measurement requires adding three numbers: the range (to 20 inches); the direct scale reading (to 0.025 inches); and the vernier reading (to 0.0001 inches). |
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