The Fountain Pen Patent Archive

The instruments that put ink under pressure

IMPROVEMENT IN PENS

A built-in overload stop to keep dip-pen tines from snapping, 1869.

PatentUS 97,735
PatentedDecember 7, 1869
InventorAddison G. Waterhouse
OfSan Francisco, California
FiledNovember 25, 1869
Three technical line drawings of a metal pen nib: a side profile showing the curved point and internal spring slot, a top view showing the slotted lever and spring structure, and a flat unbent blank showing the stamped-out slots that form the levers and shoulders.
Fig. 1 — Side view of pen showing slot, spring, and shoulder; Fig. 2 — Top view showing springs Y and lever A portions; Fig. 3 — Flat stamped-out pen blank before bending, showing slots · click to zoom
Sheet 1 of the patentSheet 2 of the patent

Metallic writing pen with spring-protecting shoulder

✒ How it works

A slot is cut into the pen body to form a spring (Y) between it and the point-slot, creating a lever (A) and a shoulder or gauge (C). When the points (d) are pressed hard against the paper and sprung upward, the levers (A) press down to rest on the shoulder or gauge (C). This shoulder limits how far the springs (Y) can flex, preventing them from being sprung beyond their safe limit. The design thereby guards the pen points from breaking off under excessive writing pressure.

✒ What was claimed

“The application of the gauge or shoulders C, acting on the levers A, so as to prevent too great a strain being put upon the springs Y, and thereby preventing the points d from being broken off.”

In plain English: The invention claims a gauge or shoulder that limits how far the pen's spring levers can flex, protecting the pen points from snapping off.

✒ In the inventor’s words

“The nature of my invention consists in protecting the springs Y, by a shoulder or gauge, C, so as to prevent the springs Y from breaking, when too great strain is put upon the points d.”— Addison G. Waterhouse, from the specification

✒ Commentary

Fifteen years before L.E. Waterman solved the feed problem, this Waterhouse — Addison G., of San Francisco, no relation established to the New York pen man — was worrying about a humbler failure: heavy-handed writers snapping the points off their steel pens. His answer is purely mechanical and rather elegant. An extra slot cut alongside the point-slit turns part of the pen body into a leaf spring with a lever arm. Press the points hard and the lever swings down until it lands on a shoulder stamped into the metal, and there it stops. The spring simply cannot flex past its safe limit, no matter how much force the writer applies.

The drawing worth lingering on is Fig. 3, the flat blank before bending. It shows that all of this — spring, lever, gauge shoulder — comes out of the die in one stamping operation, with no added parts. That is the mark of someone thinking about manufacture, not just mechanism. Overload stops of exactly this kind show up everywhere in later spring engineering; here it is applied to a pen point in 1869.

This is a dip-pen patent, strictly speaking, and sits outside the reservoir story. But flexible points and how far they can safely spread would haunt fountain pen makers for the next half century, and this is one of the earliest patents to treat tine strain as a designable limit rather than a user's problem.

Commentary by Claude, The Fountain Pen Patent Archive’s resident enthusiast

Fate unknown

Stamped steel pens were made by the million and rarely marked with patent data; a pen imprinted with this date or Waterhouse's name would settle it, and none is documented.

metallic pennib spring guardhard rubber era pen19th century writing penlever spring penSan Francisco patentpen point protector

✒ Patented the same day

This drawing is free. It is a work of the United States government, published December 7, 1869, and has been in the public domain since the day it was printed. The full original document is at Google Patents and USPTO Patent Public Search.