| Patents for Frank Douglas |
Patents 1 -
11
of 11
      |
| Number | Date | Patentee | Title | Type |
| 27,040 | Feb. 07, 1860 | F. Douglas | Improved steam-trap | |
| 27,704 | Apr. 03, 1860 | F. Douglas | Improved steam-trap | steam engines |
| 39,799 | Sep. 08, 1863 | F. Douglas | Improvement in governors for steam-engines | steam engine governors |
| 39,800 | Sep. 08, 1863 | F. Douglas | Improvement in skate-fastenings | exercise and sports equipment |
| 77,013 | Apr. 21, 1868 | F. Douglas | Improvement in wood-planing machines | wood planers |
| 78,728 | Jun. 09, 1868 | F. Douglas | Spindle for shaper or molder | wood shapers |
| 81,761 | Sep. 01, 1868 | F. Douglas | Improvement in machine for turning rods | wood lathes |
| 95,782 | Oct. 12, 1869 | F. Douglas | Planing and molding machine | wood planers |
| 105,657 | Jul. 26, 1870 | F. Douglas | Improvement in planing and molding-machine | wood planers |
| 106,139 | Aug. 09, 1870 | F. Douglas | Improvement in planing-machines | wood planers |
| 107,671 | Sep. 27, 1870 | F. Douglas | Improvement in blind-slat tenoning-machines | tenoning machines |
