| Patents for M. A. Campbell |
Patents 1 -
7
of 7
      |
| Number | Date | Patentee | Title | Type |
| 595,546 | Dec. 14, 1897 | W.J. O'Brien | Quick-Acting Vise | bench vises |
| 617,501 | Jan. 10, 1899 | C.P. Fay | Center Indicator | measurement gauges |
| D30,856 | May 23, 1899 | L.L. Davis | Design for an electric-lamp bulb | incandescent light bulbs |
| 627,668 | Jun. 27, 1899 | F.A. Holt | Combination Utensil | pot lid and stove lid lifters |
| 659,461 | Oct. 09, 1900 | F.D. Van Norman | Engraving and die-sinking machine | die sinkers |
| 665,316 | Jan. 01, 1901 | C.P. Fay | Protractor | protractors |
| 741,743 | Oct. 20, 1903 | C.E. Van Norman | Valve for compound engine | compound steam engines |
