FR Patent: FR-7,518
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Calibre à vis et vernier circulaire
Screw caliper and circular vernier (micrometer)
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Patentee:
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| Jean Laurent Palmer (exact or similar names) - Paris, France |
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Patent Dates:
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| Granted: |
Sep. 07, 1848 |
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Patent Pictures:
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From practicalmachinist.com member rivett608 |
Espacenet patent
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Joel Havens
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Description: |
| The inventor's occupation and address were méchanicien and Paris, rue Montmorency, n. 16.
The invention of the micrometer occurred surprisingly late. There is evidence that in the 1770s James Watt actually created a large bench-mounted micrometer with a U-shaped frame and a clock-like dial, but Watt kept it secret and did not patent it. Palmer independently invented and patented the U-shaped micrometer. His was much smaller and used a thimble rather than a clock face to indicate the measurement. Palmer manufactured a modest number of these himself. American machinists' tool maker Brown & Sharpe learned of Palmer's micrometer at the Paris Exposition of 1867. They had been looking for a solution to reliably measuring the thickness of sheet metal, and they based their Pocket Sheet Metal Gauge on Palmer's invention. This specialized tool did not attract a great amount of attention but when Brown & Sharpe introduced an enlarged version that could measure up to 1 inch, the modern micrometer had come of age. |
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