US Patent: 601,451
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| Lifting-jack
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Patentee:
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| Henry Minor Stevenson (exact or similar names) - Perry, IA |
| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Applied: |
Apr. 21, 1897 |
| Granted: |
Mar. 29, 1898 |
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Jeff Joslin
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Description: |
| This patent uses a recirculating-ball mechanism to create a screw-jack. This constitutes the earliest known patent for what is now called a ball screw, an invention that has become very important in the 21st century in the design of high-precision machinery with X-Y positioning, including many CNC machines. Stevenson did not invent the recirculating-ball mechanism; although the patent does not mention it, an earlier patent, Crenshaw's patent 155,862 seems to be the first appearance of recirculating balls in a screw mechanism. |
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