Various companies have used this type of loading, such as Columbus, which patented a version in 1929 (nº GB-334913), but in general it introduces unnecessary mechanical complexity and greater stress on the materials of the pen, without providing any particular benefits. It has been adopted mostly as an attempt to circumvent patents on lever filler, or as a sign of distinction with respect to other mechanisms, as it avoids the side slit for the lever, but has never been a significant success.
- Patent n° US-1213725, of 1917-01-23, requested on 1916-10-18, of Claes W. Boman, Eagle. Fountain-pen.
- Patent n° US-1216732, of 1917-02-20, requested on 1916-12-06, of James M. Reed, Eagle. Fountain-pen.
- Patent n° US-1262438, of 1918-04-09, requested on 1918-02-18, of Claes W. Boman, Eagle. Fountain-pen.
- Patent n° US-1484683, of 1924-02-26, requested on 1921-10-01, of Lewis M. Tebbel, The Parker Pen Company. Self-filling fountain pen.
- Patent n° US-1733780, of 1929-10-29, requested on 1927-05-14, of Frank C. Deli, William D. Groseclose, Autopoint. Filling device for fountain pens.
- Patent n° DE-497949, of 1930-06-13, requested on 1928-10-21, Osmia. Fuellfederhalter mit Tintenfuelleinrichtung.
- Patent n° DE-499497, of 1930-06-13, requested on 1928-10-21, Osmia. Fuellfederhalter mit Tintenfuelleinrichtung.
- Patent n° GB-334913, of 1930-09-12, requested on 1929-06-12, of Eugenio Verga, Columbus. Improvements in fountain pen.
- Patent n° GB-348036, of 1931-05-05, requested on 1930-02-05, of Frederik G. Heard, Swan. Improvements in or relating to fountain pens.