Copyright © Françoise Herrmann
The visible part of the pen in your shirt pocket is surely the clip, which bears the brand, logo, or mark of the pen manufacturer. However, the fountain pen clip did not always serve this advertising purpose...
According to William Edgar Moore, the turn of the 19th century inventor of the pen clip, and twice Assignor to the Parker Pen Company: “the detachable caps on fountain pens frequently split and break at the open end thereof in being forced onto the body of the pen” [L9-12]. This is the reason, he further explains, why pen caps are designed with a reinforcement ring at the open end, permanently attached to the cap material.
Thus, In consideration of the problematic situation of cracked fountain pen caps, and the larger issue of leak-proofing fountain pens, US1204053 discloses, in 1916, a Clip for fountain-pens that doubles as reinforcement for the pen cap, while offering a design for both securing the clip to the pen, and the pen to a pocket. In turn, the clip means of securing the pen to a pocket -- in an upright position that also prevents the pen from falling to the ground -- , at least indirectly promises to reduce the risk of “escaping ink”.
W. E. Moore’s clip for fountain pens comprises two bands for attaching the clip to the fountain pen. One band, at the bottom, completely encircles the pen cap. The other, at the top, clamps partially around the pen cap. And both bands are connected to a spine. Thus, the clip provides brace-like support and protection for pen caps.
The return bent, and resilient clip component ends with a small round ball, designed to secure the pen in a pocket. The patent further specifies that the shape of the clip is unimportant.
Thus, even if originally, the pen clip was essentially designed to reinforce pen caps, and indirectly to reduce leakage, it has endured, further acquiring prime branding status as the only visible component of a pen in a shirt pocket.
W.E. Moore’s clip for fountain pens was further specified -- sold and manufactured separately from fountain pens.