(This page revised October 9, 2015)
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As described in Anatomy of a Fountain Pen I: A Typical Lever Filler, fountain pens are simple devices. They have very few parts, and the parts of any given pen are very much like those of most other pens. One of the most strikingly different pens is the Parker Vacumatic. This article describes how the Vacumatic’s filling system is unique. The illustrations represent a pen with the Speedline filler; this pen would have been manufactured between 1937 and 1941. The illustrations depict a pen with its proportions altered for illustrative purposes. Photographs of the external appearance of the Vacumatic are shown in Profile: The Parker Vacumatic.
The Nib and Feed: The first figure shows a cutaway view of the pen without its cap or the blind cap that conceals the filler when the pen is in use:
Unlike the typical pen depicted in Part I, the Vacumatic has a section that screws into the barrel. The nib and feed are pressed into the section. In addition, a breather tube is inserted into a hole drilled into the back end of the feed, and a smaller hole connects the breather tube with the feed’s air channel. This system allows an unimpeded flow of air to the back end of the barrel, and it also provides the path through which ink is drawn into the pen when the filler is operated.
The Filling System: The next figure shows a larger view of the Vacumatic’s unique and revolutionary filling system. Although Parker advertised the Vacumatic as having no rubber sac for ink storage, the pen nevertheless does have a rubber diaphragm. The diaphragm is exposed to the ink supply, and — like a sac — can ossify.
The diaphragm is deeply cup-shaped, with a small pocket at its closed end. In the pocket is a small pellet of rubber or plastic. To install the diaphragm, a small tool is used to push the pellet into the hole at the end of the tubular aluminum plunger. The rubber of the diaphragm is stretched so that it will fit through the hole, which is just small enough to keep the pellet from popping out when the rubber is not being stretched. The open end of the diaphragm is then folded back and fitted around the tapered portion of the inner collar. No adhesive is required.
After the diaphragm is in place, the filler unit is inserted into the back end of the barrel and secured by the retaining collar. This step is also performed without adhesive. Because the retaining collar is threaded at both ends, it must be tightened with a special tool that screws onto the smaller threaded portion. This threaded portion receives the blind cap.
The retainer strip passes through slots in the inner collar and the plunger, to provide a stop against which the spring rests. The retaining collar secures the inner collar in place and also prevents the retainer strip from sliding sideways and coming out of its slots. The pinkish plug (not called out) is a relatively tight fit into the plunger; it is blocked by the retainer strip and forms a cushion for the diaphragm where it is compressed by the pellet.
Depressing the plunger compresses the spring and distends the diaphragm to drive air out of the barrel. Releasing the plunger allows the spring to extend, relaxing the diaphragm to draw ink in through the breather tube.
Differences Through the Years: The original Vacumatic filler is like the Speedline filler except that there are notches cut on the sides of the slots in the plunger. These notches are at the outer end. The knob at the end of the plunger is also a little larger in diameter than the shaft and is knurled. By depressing the plunger and turning it slightly clockwise, the user locks the plunger in its depressed position by hooking the notches over the retainer strip.
Beginning in 1942, Parker used a redesigned filler in order to conserve critical war matériel. This newer filler is much simpler in design. Its plastic plunger is smaller in diameter than the aluminum plunger. The spring in the newer model fits outside the plunger. It is attached to the plunger at the end nearest the diaphragm, and its other end is made so that it rests on the back end of the inner collar. Depressing the plunger stretches this spring. The following figure illustrates the redesigned filler:
Because the plunger is a solid rod of celluloid, there is a new part, the pellet retainer, often called the pellet pocket, to attach the diaphragm to the plunger. The pellet retainer is also celluloid, and it was manufactured with its open end in a cylindrical form, not tapered. Parker installed the pellet into it by holding the pellet in place while applying a heated tool that appears to have spun around and swaged the pellet retainer into the desired shape.
Some Vacumatic and Duofold models made during World War II have fillers in which one or both collars are made of plastic instead of metal; the plastic retaining collars are softer than aluminum and sometimes cannot be removed and reinstalled without being destroyed.
Other Anatomy Articles
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