The original Mabie Todd bulb-filler

Mabie Todd was an early entrant into the fountain pen market, but a little slower off the mark when it came to self-filling pens. Their first self-fillers are scarce, and little has been written about them to date. Made only in the USA, they were bulb-fillers -- but with a difference.

Most bulb-fillers are simple and straightforward. There is an integral sac nipple at the end of the barrel, making bulb/sac replacement easy. Not so these early Mabie Todds. Few repairmen have managed to disassemble an example. The image on the left below shows what is typically seen on an as-found pen.

The typical approach is to carefully chip away the remains of the hardened rubber bulb from between the recessed nipple and the threaded surround at the end of the barrel, and to then shellac a new bulb in place without disturbing any of what lies below. This is actually a completely legitimate approach, as I will explain below. Curiosity however compelled me to go further, revealing that the bulb nipple assembly is intended to be unscrewed, allowing it to be withdrawn from the barrel from the back.

It is possible that this unit was originally intended to be screwed and unscrewed from the front, which would have required a special spanner with a tubular body to fit around the breather tube and with small pegs to engage the vent holes in the conical front of the housing (inserting the breather tube through the barrel after the bulb assembly is in place would be rather difficult). After having worked on a few of these, though, I suspect that most repairmen did not bother removing the entire unit if the old bulb could be removed and a new one installed without any disassembly. And if the unit is to be removed, it can easily enough be done by applying torque from the back -- though reinstallation is best done before the bulb is installed, so as to facilitate retightening. [ADDENDUM: it has been pointed out that since a number of these bulb-fillers are also Ink Sight models, with a white glass strip permanently installed lengthwise inside the barrel, the standard servicing method could not have entailed turning the bulb unit from the front]

The barrel bears three patent dates, the middle of which references the filling system: Felix Riesenberg's US1037660, applied for on January 10, 1912 and issued September 3, 1912 (the other two are for Riesenberg's Ink Sight patents (US955205 and US1050295) of 1910 and 1913, even though this pen lacks the Ink Sight ink windows). Unfortunately, the patent drawings and description don't provide much information about construction details (though the lack of a separate section is touted as a feature, and it is noted that the breather tube is to fit loosely into the feed) so we are on our own in figuring out how the design was to be serviced and how the joint between the bulb assembly and the barrel was originally made ink-tight. There was surely some form of seal in the recess between the flange and the threads, but it is not clear what form it took.  

What the patent does show, though, is that the bulb assembly isn't simply a plug -- there is also a one-way check valve inside. In this pen at least, it takes the form of a thin hard rubber washer (alternative versions are shown in the patent, but were likely never produced). There should be no need for disassembly, but this is what lies inside. The valve chamber closure plug, at left, is held in place by shellac. 

The valve is intended to direct all of the air out through the breather tube when the bulb is squeezed, rather than pushing out any ink that might already be inside the barrel. Of course, standard bulb-fillers do quite well without such a valve, since the outward passage of air through the breather tube offers so much less resistance than the passage of ink through the feed channels. If Riesenberg's system does offer any greater efficiency, it must be minimal: perhaps the pen will fill using one or two fewer squeezes of the bulb than it would otherwise. Most fountain pen patents that incorporate valves and other complicated feeding and filling mechanisms are early -- the 1870s and 1880s must be the high point for such designs -- and most did not make it into production. This design is a notable though hitherto overlooked exception, with a valve that is equally notable for its simplicity and durability.

NOTE: Further research is in order, but from a preliminary survey of period trade journals the earliest mention of Mabie Todd's first self-filler that I have found is in August 1913 (see American Stationer, Aug 23, 1913, pp. 16, 19). It is mentioned repeatedly in advertisements through June 1914, but not thereafter -- a rather short run indeed. I have yet to see any mention of a valve; five squeezes of the bulb are stated to be sufficient for complete filling. Early ads and writeups tout the "Little Windows" feature as an integral part of the new self-filler's design, with the first clear indication that self-fillers could be had without the windows appearing only in ads starting in March 1914 ("Priced $2.50 upward, with "Little Windows" $3.00 and more"). Finally, in reviewing these ads it is apparent that the term "Inksight" was not consistently used for all that long after the feature's introduction in early 1912, and was almost entirely displaced by references to the "Little Windows" by the time of the self-filler's introduction (though I have run across mentions of the "Inksight" in ads as late as 1916). While David Moak's Mabie In America uses "Ink-Sight", "Inksight" is what is seen in original ads and articles.