Translations:Sistemi di caricamento/35/en
twist filler
As its name indicates, the twist filler is based on the compression of the reservoir through the exercise of a torsion on it. In this type of filling in general the tank is made not with a sac, but with a rubber tube whose rear end is glued to the bottom of the body of the pen that can be rotated, so as to generate the twist that literally "squeezes" the same.
Although it has some advantages compared to the traditional lever filler, such as greater mechanical simplicity and the aesthetic merit of not needing a lateral opening on the body of the pen, the main defect of this system, which decreed its substantial failure, was the greater ease with which the rubber tank could break due to the considerable effort imposed on it by the torsion.
The system was mainly used by A. A. Waterman who around 1902 acquired a patent (nº US-744642, attributed to Harry W. Stone) relating to it. Other companies introduced similar systems, or inspired by the same principle of rotating the bottom of the pen to squeeze the tank, such as the leverless of the Swan. A very particular version of this type of loading was used on a prototype pen of the Nettuno never marketed.