| Patents Granted on 1891-04-21 |
Patents 1 -
15
of 20
      |
| Number | Date | Patentee | Title | Type |
| 450,640 | Apr. 21, 1891 | R.C. Smith | Slide Rule for Logarithmic Calculations | slide rules |
| 450,641 | Apr. 21, 1891 | W. Stanley, Jr. | Self-exciting alternate-current electric generator | |
| 450,651 | Apr. 21, 1891 | D.E. Van Horn | Wrench | pipe wrenches |
| 450,676 | Apr. 21, 1891 | T. Newman | Pipe Wrench | pipe wrenches |
| 450,681 | Apr. 21, 1891 | D.R. Porter | Wrench | pipe wrenches |
| 450,707 | Apr. 21, 1891 | B.F. Bennett | Wrench | quick adjust wrenches |
| 450,733 | Apr. 21, 1891 | G. Stroner | Metal Turning Tool | lathe tools |
| 450,771 | Apr. 21, 1891 | H. Lindley | Apparatus for Controling the Circulation of Liquid Through Cylinder Jackets of Gas or Other Motors | cooling apparatus |
| 450,823 | Apr. 21, 1891 | C.W. Fuller | Bevel | bevels |
| 450,874 | Apr. 21, 1891 | J. Schwarzmann | Rotary Engine | rotary steam engines |
| 450,879 | Apr. 21, 1891 | B.B. Allen | Reamer | reamers |
| 450,892 | Apr. 21, 1891 | W.H. Potter | Scriber | scribes |
| 450,908 | Apr. 21, 1891 | L.A. De La Nux, W. Brede | Auger | drill bits |
| 450,957 | Apr. 21, 1891 | H.J. Williams | Device for removing corks from bottles | bar corkscrews |
| 450,965 | Apr. 21, 1891 | E.S. Matthews | Elevator-valve controller | |
