| Patents for American Twist Drill Co. |
Patents 1 -
7
of 7
      |
| Number | Date | Patentee | Title | Type |
| D3,603 | Aug. 03, 1869 | T.H. Worrall | Design for a grinding-machine | bench or pedestal grinders |
| 463,812 | Nov. 24, 1891 | A. Lesperance | Clutch | metalworking power transmission |
| 463,820 | Nov. 24, 1891 | T.H. Worrall, A. Lesperance | Clutch | metalworking power transmission |
| 559,558 | May 05, 1896 | T.H. Worrall, A. Lesperance | Friction-clutch | metalworking power transmission |
| 586,263 | Jul. 13, 1897 | T.H. Worrall, A. Lesperance | Power-shifting device for clutch mechanisms | metalworking power transmission |
| 606,634 | Jun. 28, 1898 | T.H. Worrall, A. Lesperance | Friction-clutch | metalworking power transmission |
| 834,857 | Oct. 30, 1906 | T.H. Worrall | Clutch | metalworking power transmission |
