Skip to content

The Fountain Pen Patent Archive

The instruments that put ink under pressure

Browse Dates Inventors Types About

Plug-valve

Patent drawing of a hard rubber fountain pen shown in full diagonal view with a cutaway section revealing the internal feed-bar, pen-point, and plug-valve, alongside smaller detail views of the triangular feed-bar cross-sections and the pen-point's locking projection.

FOUNTAIN-PEN.William H. O'Keefe · October 1, 1895

United States patent drawings and specifications are works of the U.S. government and are in the public domain — they were never copyrighted. Download them, print them, frame them. Our commentary and descriptions are © 2026 The Fountain Pen Patent Archive.

About · Terms · Privacy · Corrections welcome — this archive gets better when collectors write in.