Lever filler

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Versione del 21 ago 2019 alle 00:14 di Piccardi (discussione | contributi) (Creata pagina con "Another noteworthy variant of the system is the one of Carter, derived from a patent ({{Cite patent|US|1209978}}) of the De Witt-La France, which has a sort of "leash"...")
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The lever filler is probably the filling system most common among vintage pens (and has also been used, as a form of revival, by some modern manufacturers). Introduced massively to the market in 1912 by Sheaffer, who has always proclaimed its invention, it has been produced in countless variations and versions, many of which, often technically inferior, have been created only to circumvent the patent (nº US-896861) that covered the invention of Walter Sheaffer that originated in 1908.

Diagram of a pen with lever filler

In fact, the ancestry of Sheaffer is seriously under discussion; in fact, there are previous versions of this loading system, a Swedish Johansson patent from 1898 and an American Barnes patent (nº US-726495) from 1903, the presence of which has allowed other companies, such as Waterman, to use variants of the same system. However, the success of the system and its enormous diffusion can be attributed to the massive investments of Sheaffer.

In the case of the Sheaffer patent the mechanism involves the compression of the sac using a lever that press on an elastic metal bar (the so-called spring bar) shaped like a "J", this one is inserted in the body of the pen with the curved part towards the bottom so as to make to adhere the straight part on the barrel of the pen, in correspondence of the lever. In many cases the pressure on the sac is not directly exerted by the spring bar that is hooked to a pressure bar which is the one that is pressed against the bag.

In the rest position the lever is placed horizontally in a slot in the side of the pen body. In the original version of Sheaffer it was held in place by a thin metal pin that crossed it centrally, inserted directly into the shaft of the pen, which was drilled for the occasion. Lifting the lever from one side the other side pushes down the pressure bar, which thus compresses the sac.

As mentioned above, there are several different versions of this mechanism. For example, Waterman, in order to circumvent Sheaffer's patent, introduced, based on Barnes's patent, a lever pivoted directly inside a metal cage that contained the entire mechanism. This in turn was fixed with fins to the pen, using as housing a special slit created in the barrel side.

A more efficient system, later used by other producers including Sheaffer itself, requires the lever to be held in place by a metal ring through it. This is inserted inside the pen and maintained in position by means of a special groove, made internally on the barrel in correspondence with the lateral opening from which the lever itself is housed. This system has the considerable advantage of greater mechanical strength, since it does not require drilling holes for the pin in the material of the barrel, which in ebonite pens was often quite fragile.

Other variations of the system concern the way in which the lever exerts pressure on the sac: for example the Eversharp did not use a flexible bar but a flat bar with the sides folded like a "U", anchored on a hook on the bottom of the pen. The lever was equipped on the external end with two tips that went to fit in the rail obtained from the folding of the bar, so as to raise it to the rest position after filling, furthermore to keep the lever locked in the rest position, it was equipped with small protrusions that went to fit into special recesses created in the housing slit.

The Conklin with the Endura introduced a version in which only half of the lever being lifted was exposed externally, reducing the size of the slit on the barrel. Moreover, the mechanism used by Conklin, like that one of Eversharp, did not use a spring bar, but a pressure bar was stuck directly to the lever by means of two small hooks inside it, which went to fit into a special hook on the bar.

Another noteworthy variant of the system is the one of Carter, derived from a patent (nº US-1209978) of the De Witt-La France, which has a sort of "leash" attached to the lever that prevents it from tipping over once it has reached the vertical position, in order to avoid damage to the pen and the system.

Infine una particolare versione di riempimento a levetta è quello della Skyline della Eversharp, che potrebbe essere classificato anche fra i caricamenti a sfiatatoio. In tal caso infatti all'interno del serbatoio in gomma si ha uno sfiatatoio, e la spring bar è molto corta e volta a comprimere soltanto la parte finale del sacchetto. La penna viene caricata ripetendo più volte l'azione di pressione con la levetta, usando il principio classico dello sfiatatoio. Analogo a questo, anche se realizzato in maniera completamente diversa, è l'Ink-Vue della Waterman.

Brevetti correlati

  • Brevetto n° US-1249501, del 1917-12-11, richiesto il 1916-06-27, di Felix Riesenberg, Swan. Sistema di caricamento.
  • Brevetto n° US-1251421, del 1917-12-25, richiesto il 1915-11-29, di Felix Riesenberg, Swan. Sistema di caricamento.
  • Brevetto n° US-1267288, del 1918-05-21, richiesto il 1916-10-19, di Tagiro Tanimura, Swan. Sistema di caricamento.
  • Brevetto n° US-RE14474, del 1918-05-21, richiesto il 1918-03-28, di Felix Riesenberg, Swan. Sistema di caricamento.
  • Brevetto n° GB-118118, del 1919-09-08, richiesto il 1916-06-27, di Felix Riesenberg, Swan. Sistema di caricamento.