Modifiche

<noinclude>{{ReferBox|Filling systems}}</noinclude>The loading system called ''Touch Down'' by the company itself was introduced by [[Sheaffer]] in [[1949]] for the [[Touchdown|homonymous models]], and is nothing more than a more sophisticated reworking, carried out after twenty-five years (patent {{Cite patent|US|2610612}}), of the [[Chilton]] [[pneumatic filler]] system (whose patent, {{Cite patent|US|1528379}}, is mentioned explicitly). In fact, the operating principle is essentially identical, what changes is the way in which the pneumatic compression of the rubber sac inside the pen is carried out.  

<noinclude>{{ReferBox|Filling systems}}</noinclude>The loading system called ''Touch Down'' by the company itself was introduced by [[Sheaffer]] in 1949 for the [[Touchdown|homonymous models]], and is nothing more than a more sophisticated reworking, carried out after twenty-five years (patent {{Cite patent|US|2610612}}), of the [[Chilton]] [[pneumatic filler]] system (whose patent, {{Cite patent|US|1528379}}, is mentioned explicitly). In fact, the operating principle is essentially identical, what changes is the way in which the pneumatic compression of the rubber sac inside the pen is carried out.

Also in this case there is an unscrewable bottom that is hooked to a metal cylinder that slides hermetically thanks to a gasket along the body of the pen, the mechanism is however much more complex to avoid the use of the ventilation hole on the bottom of the pen and allow compression only by pushing down the tube anchored to the bottom once you have extracted it.  

Also in this case there is an unscrewable bottom that is hooked to a metal cylinder that slides hermetically thanks to a gasket along the body of the pen, the mechanism is however much more complex to avoid the use of the ventilation hole on the bottom of the pen and allow compression only by pushing down the tube anchored to the bottom once you have extracted it.