US Patent: 1,117,140
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| Portable electrically-driven tool
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Patentee:
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| Joseph A. Osborn (exact or similar names) - St. Louis, MO |
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Patent Dates:
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| Applied: |
Dec. 12, 1913 |
| Granted: |
Nov. 10, 1914 |
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Jeff Joslin
Vintage Machinery entry for Chicago Pneumatic Tool Co.
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Description: |
| This patent covers the "Osborn Safety Device". On highly geared drills with powerful motors, the tool can be twisted out of the operator's hands if the bit binds; the Osborn Safety Device stops the drill very quickly when that happens. The device provides a dead-man switch on the handle that, when released, disconnects the motor from power and reconnects the motor as a generator and across a resistor, which stops its rotation within a half a revolution. A 1914 bulletin from the Chicago Pneumatic Tool Co. describes this invention. An article in the October 1917 issue of Safety Engineering also describes it, and notes that it had been placed on the list of approved safety devices from the Pennsylvania Department of Labor and Industry. |
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