In 1924 Seth Chilton Crocker resumed the idea of the blow filler invented by his father Seth Sears Crocker, further refining it using a new patent (nº US-1528379, by David J. La France). The new system was based on the fact that the body of the pen slides around a metal tube screwed on the nib assembly to which was mounted the classic rubber sac to compress. To perform this action, the outer barrel of the pen could slide on the inner barrel and the watertight seal between the two was made by a waxed wire placed at the end of the inner metal cylinder.
The outer barrel of the pen had, as for the blow filler an aeration hole on the bottom. The filling was obtained by sliding back the body of the pen and then bringing it back into position by keeping the hole in the bottom closed with a finger. In this way the pressure generated on the sac causes its compression, but once left free the aeration hole the subsequent expansion of the sac causes the suction of the ink.
The system was simple, functional and sturdy, all the space included in the inner barrel was usable for the bag (without the need for a pressure bar as for lever filler) which allowed the Chilton to have a much higher autonomy than the competitors. Moreover this simple mechanism was very easy to repair, it was enough to unscrew the inner barrel to replace the sac. Finally, the presence of the aeration hole allowed to keep balanced the internal pressure of the pen, so that it did not present problems of leakage or absence of ink in case of variations in pressure or temperature.
Simplicity was a strength of the Chilton, the outer barrel was not even anchored to the nib assembly, as this was not necessary because for the mechanical precision of the machining it did not flow during use. The only drawback was that to work the pen required a longer nib assembly length to handle the pen once the body had been retracted for fillig, which had to be done with two hands. Since the thread for the cap was placed on the outer barrel of the pen (so that it was locked when the pen was closed), this also meant a longer cap length, and therefore an unproportionate appearance.
For this reason in 1927 was created a second version of the filling system, in which the outer barrel was anchored conventionally to the nib assembly, and in its place was used to generate depression a second metal tube placed between it and the inner barrel. The depression system was anchored to the bottom of the pen which was a blind cap, in this way it was sufficient to unscrew the bottom of the pen to perform the loading, which at this point could be performed with one hand.
The Chilton however does not seem to be the only manufacturer to have used this system, in fact a substantially identical system called Compressor was invented by Montblanc in 1923 (patent nº DE-400356) and used from 1924 to 1929 for some models, which however were marketed on a small scale (mainly in France) and did not have a significant success.
- Patent n° US-825442, of 1906-07-10, requested on 1906-02-26, of Frederick William Bender, Unbranded. Fountain-pen.
- Patent n° US-1134936, of 1915-04-06, requested on 1914-03-28, of Julius Abegg, Chilton. Fountain-pen.
- Patent n° US-1528379, of 1925-03-03, requested on 1924-02-29, of David J. La France, Chilton. Fountain pen.
- Patent n° US-1580093, of 1926-04-06, requested on 1925-06-11, of Henry J. Upton, Chilton. Fountain-pen.
- Patent n° US-1755586, of 1930-04-22, requested on 1928-10-03, of Edward C. Berry, Chilton. Fountain pen.
- Patent n° US-1801635, of 1931-04-21, requested on 1929-03-15, of William E. Moore, The Parker Pen Company. Fountain pen.
- Patent n° US-1840110, of 1932-01-05, requested on 1930-07-18, of Henry Krause, Chilton. Fountain pen.
- Patent n° US-1883160, of 1932-10-18, requested on 1929-09-06, of Henry J. Upton, Chilton. Frictional packing.
- Patent n° US-1902633, of 1933-03-21, requested on 1931-10-24, of William J. Foley, Chilton. Fountain pen.
- Patent n° US-2017109, of 1935-10-15, requested on 1932-12-05, of Milford G. Sypher, Chilton. Fountain pen.
- Patent n° US-2017110, of 1935-10-15, requested on 1932-12-17, of Henry J. Upton, Chilton. Fountain pen.