Design Features: Safety Pens

(This page revised October 13, 2015)

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The Problem

Early fountain pens were all too likely to leak in the user’s pocket. The first generation of manufacturers made their pens of hard rubber and fitted them with slip caps in two general types: the straight cap (illustrated below, upper), which slips onto a cylindrical area at either end of the barrel — to cap the pen or to post the cap for writing — and the cone cap, with a bore that is conically tapered instead of cylindrical (below, lower). A cone-cap pen’s barrel tapers at the back end in the same manner as at the front in order to provide a place for posting the cap.

Pen with straight cap
Pen with cone cap

Hard rubber slip caps are not all that reliable. With use, a straight cap wears and becomes loose, and it can slip off when the pen is in a shirt pocket or a purse. A cone cap, on the other hand, is not tight at all unless it’s forced onto the tapered barrel. But if the user forces the cap on too tightly, the cap can split. Carrying the pen nib upward, then, is risky in case the cap lets go. Carrying the pen in some other attitude, such as nib downward, is even more risky; the reservoir can leak into the cap if the pen is jostled. Furthermore, most early pens had vent holes in their caps that could leak directly onto the user’s clothing even while the pen remained capped.

Solving the problem of slip-cap unreliability is the first step to creating a pen that is “safe.” One solution is threaded caps, which began to appear in the last decade of the 19th century. One early threaded-cap pen is Moore’s Non-Leakable Safety Pen:

Fountain pen Magnifying glass

But simply threading the cap is not enough. The presence of vent holes still provides a relatively unimpeded path for ink to leak from the pen’s reservoir onto the user’s clothing. Solutions to this problem became known as “safety” pens because they could be carried safely.

Some Solutions

Morris W. Moore’s Non-Leakable Safety Pen (U.S. Patents Nos 567,151 and 567,152), illustrated above by a compact (458" capped) No 2 Tourist, was one of the earliest safety pens. Here is another Non-Leakable, a much larger No 450:

Fountain pen Magnifying glass
Fountain pen Magnifying glass
Fountain pen Magnifying glass
Moore’s Non-Leakable Safety Pen No 450. Top to bottom: capped,
posted, retracted but uncapped. (from the collection of Robert Tuthill)

This eyedropper-filling pen takes the threaded-cap concept one step further by providing a retractable nib. (Instead of screwing the pen apart to fill it as with an ordinary eyedropper filler, you simply put the ink in through the opening the nib leaves when retracted.) The nib is mounted on a slender shaft that is also the feed. At the end of the shaft is a knob; to retract the nib, you pull the knob.

The retracted nib leaves a conical opening that is plugged tightly by a short cylindrical projection on the inside of the cap, providing an ink-tight seal when the pen is capped. There is a complete exposition of this design, including cross-section diagrams, here.

Thus, as long as the cap remains secure, there is no risk of leakage with the pen in any attitude. The American Fountain Pen Company, maker of Moore’s pen and renamed in 1917 as the Moore Pen Company, was not slow to point out this advantage in its advertising:

“Every person that has carried a Fountain pen realizes the necessity of carrying it in the pocket POINT UP, as directed, or their clothing will soon be badly soiled with ink; also their hands when using it. NOT SO WITH THESE PENS. Being AIR and INK TIGHT, they can be carried in ANY POSITION IN ANY POCKET when filled with ink, and cannot leak…”

Other safety-pen manufacturers made the same point in different words.

In Moore’s pen, the nib is held in the extended position only by friction. This system works quite well, but some engineers wanted to create what they thought would be a more positive design. “More positive” implies ”more complicated,” and Waterman’s Ideal Safety Pen is definitely more complicated.

Fountain pen Magnifying glass
Fountain pen Magnifying glass
Waterman’s Ideal No 15S

Introduced in 1907 or 1908 and based on patents by Francis C. Brown (U.S. Patent No 612,013, issued in 1898, and U.S. Patent No 949,752, issued in 1910), Waterman’s pen uses a long-pitch screw mechanism (a helical cam) within the barrel to extend the nib. The operating knob is just the right diameter to wedge gently into the cap when the cap is posted (enabling use of the cap as a knob that is easier to grasp).There is a complete exposition of this design, including cross-section diagrams, here.

Waterman’s pen had a drive shaft with two helical slots in it to apply force evenly across the length of a pin that moved the nib in and out. Many “copycat” manufacturers used only one helical slot and, correspondingly, only one barrel groove. Some of them even avoided having to make and assemble a crosswise pin by bending the end of the carrier over at a right angle and filing it to a shape that would ride in the helical slot. The single-slot version is less costly to make, but it is also less reliable. Interestingly, it is also the version Brown described in his original patent and manufactured under his Caw’s brand (shown below, a Caw’s No 327 made in about 1910).

Fountain pen Magnifying glass
Fountain pen Magnifying glass

A Gallery of Waterman-Style Safety Pens

As with any other pen design, manufacturers seem able to produce a virtually infinite variety of styles. Here is a small sampling of the incredible variety of vintage safety pens using the basic design of Waterman’s mechanism.

Fountain pen Magnifying glass
Fountain pen Magnifying glass
Waterman’s Ideal No 42, Art Deco gold and sterling overlay. 42532"
capped (from the collection of Beaumont Vance)
Fountain pen Magnifying glass
Fountain pen Magnifying glass
Waterman’s Ideal No 4212VS BABY sterling overlay.
312" capped (from the collection of Nancy Kassim Farran)
Fountain pen Magnifying glass
Fountain pen Magnifying glass
Fendograf (Italian), green gold-filled overlay. 42132" capped
Fountain pen Magnifying glass
Fountain pen Magnifying glass
Regina No 410 (German), BCHR. 518" capped
Fountain pen Magnifying glass
Fountain pen Magnifying glass
Siekling (German) floral enameled pen. 3716" capped

The End of the Line, for Waterman at Least

All good things must come to an end, including the remarkably long product life of Waterman’s retractable safety pens. The last of the line, shown here, disappeared from the catalog in 1936. This pen has no number on its barrel end, and the barrel imprint reads only Waterman’s / MADE IN U.S.A. The pen has a No 2A artist’s nib; many of these last-model safeties were intended for drawing. Note the washer clip.

Fountain pen Magnifying glass
Fountain pen Magnifying glass

On the other hand, the fact that the best known manufacturer of a product discontinues it does not mean that the product is defunct. Helical-cam safety pens remained in production into the 1960s, as illustrated by this early ’60s Ultraflex pen imported to the U.S.A. by the Ropex Company of New York City:

Fountain pen Magnifying glass
Fountain pen Magnifying glass

And Now for Something (Almost) Completely Different

Popularity is not always linked with superior engineering. The proliferation of Waterman-type safety pens should not be taken to imply that this design was the best possible within the technological limits of the time. Stepping back to the concept of a threaded cap, but forgoing the complexity that a retractable nib adds, we find the Parker Jack-Knife Safety pen, the forebear of one of the most successful pen designs of all time:

Fountain pen Magnifying glass
Fountain pen Magnifying glass
Fountain pen Magnifying glass
Parker Jack-Knife Safety No 23, BHR eyedropper filler,
c. 1912 (from the collection of Daniel Kirchheimer)

Parker’s pen qualified as a safety pen by virtue of its threaded inner cap (U.S. Patent No 1,028,382). Note that this patent permits a nonretractable nib but does not specify whether the outer cap is threaded or a slip fit. The patent describes the invention as follows:

“…said inner cap being screwed into the outer tubular sleeve so as to be adjusted tightly and accurately against the mouth of the nozzle after the outer sleeve or main cap has been put in place upon the barrel.”

By adding to the section a flange against which the end of the inner cap could seal, Parker created an ink-tight seal. The two-step process of capping was not as straightforward as it might be, and Parker soon simplified the user’s handling by providing a threaded outer cap into which the inner cap was screwed to a fixed position. Screwing the outer cap down until the inner cap stops against the section seals the pen. Parker was not the first to adopt this design, however; the original patent for the concept was issued to August Eberstein in 1904 (U.S. Patent No 764,227) for the Boston Fountain Pen Company. This simple design is obviously superior to the more complex retractable designs, but retractables continued to sell, in dwindling numbers, for more than 20 years after the appearance of the Jack-Knife Safety. The earliest Jack-Knife Safety pens were eyedropper fillers.

In 1912 or 1913 Parker introduced a completely new pen featuring the button filling system patented in 1905 by John T. Davison (U.S. Patent No 787,152), licensed to Parker and slightly modified for more economical manufacture.

In a button filler, pressing the button attempts to compress s leaf spring lengthwise. With its other end resting on a ledge in the section, the spring resists, instead bending away from the barrel wall to push the pressure bar itself into the sac to compress it. Releasing the button allows the spring to return to its rest shape, in turn allowing the sac to re-expand and take in ink. At first consideration, a button filler does not seem very “safe”; after all, it has a hole in the back of its barrel through which the button itself must pass. But the blind cap, when screwed in place securely, forms an ink-tight seal against the end of the barrel to render the pen proof against inadvertent leaks. This feature was an essential part of Parker’s “Safety-Sealed” system, which provided the company with advertising copy for the next several years. Ironically, the first button fillers Parker sold had ordinary “unsafe” slip caps:

Fountain pen Magnifying glass
Fountain pen Magnifying glass
Fountain pen Magnifying glass

The second half of the “Safety-Sealed” system was Parker’s elimination of the then-standard breather hole or holes in the cap. The cap of the pen shown above fits so smoothly and tightly that the user feels the resistance of compressed air when capping the pen too hastily. Only a few years later did the company combine the button mechanism and the Jack-Knife Safety cap. In 1916, the company patented its famous washer clip and soon thereafter began applying it to pens to produce the shape of the pen shown here:

Fountain pen Magnifying glass
Parker Jack-Knife Safety No 2312, BCHR button filler, c. 1918

This shape is more widely recognized in the 1920s descendant of the Jack-Knife Safety, the famous flat-top Duofold:

Fountain pen Magnifying glass
Parker “Big Red” Duofold Senior, c. 1924

The basic design of the Duofold continued in manufacture, with styling updates, into the 1940s with models such as the Duofold Geometric and the Challenger line, and with a filler change, the Vacumatic and its kin (but not the “51”). All of these pens are safety pens in the sense originally meant by their manufacturers, i.e., that they are safe from inadvertent leakage. (The “51” is not a safety because its clutch cap, although remarkably secure, is not proof against slipping off the pen.)

Note
Note
The nonretracting pens discussed here are safety pens in the original sense of the term, as indicated above, but they are not safety pens in the sense generally understood by today’s collectors, which arbitrarily limits the term “safety” to mean pens with retractable nibs.
Safeties Today

By definition, any screw-cap cartridge/converter pen is a safety (by the original criteria) so long as the barrel is without holes (in case of cartridge or converter failure) and the cap seals the nib area when screwed on. (Not all pens’ screw caps form a good seal!) Also, considering that Parker’s button fillers are safeties, the same can be said of modern button fillers from such makers as Krone and Filcao.

Fountain pen

Filcao Silvia LE, “horn” body, ivory resin cap, 2005

But the enhanced security of a retractable nib retains a certain appeal, and Montblanc’s Bohème (smaller version shown here) is a true retractable safety, using a twist-knob mechanism that is essentially the same as the original Brown design.

Fountain pen
Fountain pen

Montblanc Bohème

Safety’s in the Mind of the Beholder

How safe is safe? In strict terms, retractable modern safeties like the one shown here are not truly “safe.” Their retractable mechanisms keep the nib safe, but the back ends of these pens are not sealed and will leak should a cartridge or converter fail. In practical terms, on the other hand, these pens can be considered as safe as Waterman’s and Moore’s designs, which can leak if their corks dry or wear out.


The information in this article is as accurate as possible, but you should not take it as absolutely authoritative or complete. If you have additions or corrections to this page, please consider sharing them with us to improve the accuracy of our information. I am indebted to Daniel Kirchheimer, who contributed much useful information and guidance in the creation of this article.

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