Pen Mechanisms Revealed – 2. Ford’s Patent Pen

Laurence Oldfield

Introduction

Ford’s Patent Pen (Figs.1,2) was the brainchild of one of the most innovative of fountain pen designers, George Stewart Vivian. In 1930 and 1931 he produced a number of UK patents aimed towards a pen with large ink capacity, good ink visibility and safety against leaks. T. B. Ford Ltd, famous for their blotting paper, marketed the pen in 1931 at Snakeley Paper Mill near High Wycombe. Almost certainly, they did not manufacture or even assemble the pen. The precision engineering in hard rubber, arguably the best in any pen of the period, would have required extensive experience in pen making. We could speculate that Valentine, Wyvern, or even De La Rue, had a hand in the development and production.

Ford pens are characterised by their large uniform diameter, a feature that inevitably resulted from their double skin design. The transparent ink reservoir was novel in the 1930’s, and it may well have been these pens that started the subsequent craze for ink visibility. Ford pens were produced in vulcanite (hard rubber) in four basic sizes (Fig.3), lady, standard (long and short), Magnum and desk pen. The finishes available were black, red/black mottle and metal overlays. The barrels were imprinted with two patent numbers relating to the development of the pen. These patents form the only technical literature of the time that relates to the design philosophy and the technical specification. No repair manuals appear to exist, so it is not surprising that there is little appreciation of the physical principles underlying the operation of these pens, the function of the components, or even of how the filler seals may be replaced.

Components and mode of operation

Although bearing superficial resemblance to the De La Rue Onoto piston filler pens of the time, the filling mechanism is quite different. Ford pens use a variation of the syringe type filler, shown in its simplest form in Fig.4, where the pen fills on the pull stroke. The problem of what to do with the plunger knob in syringe fillers was neatly solved by the use of a sliding seal (shown as a valve for simplicity in Fig.4) that permits the transfer of ink to the other side of the seal on the push stroke. A cork seal at the top of the pen prevents leaks, and the long breather tube provides a means for the air to escape. Note that the valve stays open during writing, so that ink can pass to the feed.

Fig.5 shows the parts. The earlier models used a tinted transparent ink reservoir threaded at both ends. Some problems with this must have been encountered because in 1934, a new ‘unbreakable’ clear Perspex-like reservoir was introduced (Fig.6); this was threaded only at the nib end, the other end having an integrated plunger seal. This modification has implications for the repair procedure, as we shall see later. Ford pens contain a spring within the plunger knob, the function of which is to release an internal ink seal when the pen is in use: as the cap is screwed on, the barrel sleeve is drawn up further over the reservoir against the spring so that the filler nose seals the mouth of the feed. For this reason the user is advised to screw the cap on hard to avoid the possibility of leaks when the pen is not in use.

The instructions for the pen state that it will be ‘supplied full of water’, presumably to prevent drying out of the cork plunger-seal and the leather filler-washer. The filling operation is claimed to be complete in about 3 or 4 strokes of the plunger, but it is advised that no harm can come to the pen by increasing the number of strokes, and that the pen should not be withdrawn from the ink with the knob in the extended position. Some ink will always be expelled when the knob is finally pushed home because the bypass channel in the plunger rod is not large in comparison with the ink channel. This could account for the fact that it does not seem possible to achieve the ink capacity that was advertised.

Technical development – the patents

A number of different patents submitted by Vivian are relevant to the development of the Ford pen. Two of them are quoted on the pen barrels (numbers 337794 and 337835 accepted in November 1930 and October 1931 respectively). Four more important patents were accepted in June and July 1932 after the pen had appeared on the market (numbers 359230, 375457, 375458 and 376019).

337794 (Vivian and Valentine & Sons) introduced the idea of a large, transparent and detachable ink reservoir (Fig.7). The nib unit was separable from the reservoir and sealed by a ball valve that was part of the pumping mechanism. When the reservoir was mounted, ink was automatically released to the nib. The ink reservoir fitted inside the body of the pen, and this carried the section and nib. The pen used a pump-filler with bypass mechanism to allow the transfer of ink above the washer during the push stroke. The patent recognised the need for an air vent at the top of the reservoir during filling, but gave no clear statement how this could be achieved without ink leakage.

337835 (Vivian and Valentine & Sons) dispensed with the removable reservoir, claiming that the advantages of this could be achieved with a fixed one. The emphasis was on the short stroke (thumb operated) filling method, but again no indication was given on how the air at the end of the reservoir could be expelled without ink leakage. Little of this patent is relevant to the Ford pen, so it seems a little strange that it should have been quoted on the barrels.

359230 (Vivian and T. B. Ford Ltd) describes a safety pen with automatic cut-off of the ink supply when the nib is retracted. Its significance to the Ford pen lies in the fact that the vent problem was solved by provision of a breather tube to allow air displaced by the ink to escape. The pen illustrated is chunky in shape and it may well have influenced the appearance of the production pen.

375457 (Vivian and T. B. Ford Ltd) introduces the idea of a pen with transparent celluloid ink reservoir covered with a thin detachable sleeve to offer concealment and protection (Fig.8). Material for the sleeve was proposed to be vulcanite or precious metal with the possibility of perforations in a pattern to aid decorative value. Reference was made to a self-filling system, but the explanation of this was left for Patent 375458.

375458 (Vivian and T.B. Ford Ltd) was the first to describe the long stroke filling system. This used a sliding washer and slotted plunger rod to allow the transfer of ink to the upper part of the reservoir. A long breather tube within the plunger allowed trapped air to escape at the nib. The principles of this idea were explained in great detail, and it is clear that this design was followed closely in the production pen.

375458 (Vivian and T.B. Ford Ltd) describes the pen virtually as produced (Fig.9). The novel aspect of the patent is the introduction of a much improved method of ink cut-off when the pen is not in use. Cut-off occurs within the reservoir by sealing the entry to the feed. This is achieved as the cap is screwed on, thereby drawing the sleeve further up over the reservoir against the action of a spring concealed within the plunger knob. It was claimed that the pen cannot leak ink, even into the cap.

Dismantling and renewal of seals

The first step is to unscrew the section from the front of the ink reservoir. The threads may be stiff and it may be necessary to use soaking in water and/or hot air to release them. Be sure to grip the reservoir with soft-jawed pliers over the threaded region. For the earlier pens there is a choice of procedure: either remove the knob, or the reservoir end-plug. The later pens leave no option but to remove the knob, which is not threaded on like the Onoto knob; it is a sliding fit and is held by a hard rubber cross pin. Ford pens were so well made that it is sometimes quite difficult to locate the end of the pin. First mark the alignment of rod and knob at the end and then punch out the pin only so far as is necessary to remove the knob. After removal of the spring, withdraw the mechanism carefully through the front of the reservoir. The plunger rod is in three pieces screwed together on left handed threads; these must be unscrewed to allow replacement of the plunger washer. This washer is ideally a domed silicone rubber one, but a flat leather washer will suffice if treated well with silicone grease. The washer must be able to slide easily on the rod so that it can make a seal with the plunger nose to enable ink to be drawn into the reservoir during the pull stroke, and be free to slide back again to transfer ink above the seal during the push stroke. The cork seal at the top of the reservoir plays no significant part in the filling mechanism; it is there chiefly to prevent the leakage of ink, though once filled, the reservoir must not admit atmospheric air or the nib will flood. The seal is held in place in a similar way to the Onoto pens and is renewed using similar tools (WES Journal No.57). When the threaded washer has been removed the old seal can be picked out and the reservoir thoroughly cleaned. The assembled rod is pushed in from the nib end until it protrudes from the other end of the reservoir. At this stage a new cork seal can be fitted using silicone grease. The threaded washer is then replaced and tightened until a good seal is made with the piston rod. The pen can then be reassembled (Fig.10) and the nib/feed adjusted for good ink flow.

Using the Ford pen

The pens are exceptionally rapid filling. Whereas a Vacumatic may require 15 or more cycles of the plunger to achieve complete filling, the Ford requires only two or three, and it is amazing to see the ink gushing into the reservoir. The Magnum was advertised as holding 8ml of ink, but the ink reservoir, when full can hold only 7.3ml by my measurements. This compares with the 3.3ml capacity of the Parker Oversize Vacumatic and the 1.2ml capacity of the Parker 51.

The pens are perhaps not the most comfortable to use, particularly the Magnum model which has a diameter of 14mm at the gripping point, and it does feel weighty when full. One significant problem is associated with the ink cut-off valve. If the pen is used immediately following removal of the cap, and hence release of the valve, there is a risk of flooding. As the cut-off valve seals all parts of the mechanism, flooding could be caused by changes in the differential pressure of the air in the top of the reservoir as a result of small changes in atmospheric pressure since the pen was last used. This pressure difference is very critical as it enables fountain pens to retain their ink and to release it at a controlled rate through the nib on to the paper. I have found it best not to screw the cap on tight enough to operate the valve unless the pen is to be out of use for some time. The double sleeve design with an air gap does mean that Ford pens are much less vulnerable to temperature induced pressure changes than single skin designs such as the Parker Vacumatic or Onoto plunger filler.
Nibs were available in 20 different styles, including a ‘spade’ type nib 2.5mm across the tips. Generally, nibs tend to be rather stiff in the Parker style. These pens are rare and collectible and they are fascinating to the pen engineer. They are good reliable workers and are an excellent choice for someone who enjoys writing with a fountain pen.

The Ford pens are certainly worth the effort of restoration because they are so different from any other fountain pen, and they retain the novelty of having such a large ink capacity.

Please contact the author if you wish to purchase a repair manual and a tool to enable replacement of the cork seal, or if you would like the restoration done for you.

References

Roe G E (1996) Writing Instruments - A technical history and how they work.
Hull S. The Valentine Pen including Ford’s Patent Pen, WES Journal, vol.46, pp21-29, 1996.
UK Patents (Accepted): 337794 (November 1930), 337835 (November 1930), 359230 (October 1931), 375457 (June 1932), 375458 (June 1932), 376019 (July 1932).
Twydle A. and Marshall J. Repairing Onoto piston fillers, WES Journal, vol.57, pp15-17, 2000.

Acknowledgement

I am indebted to Steve Hull for his helpful comments and for finding the patents and the advertisements and to Geoff Roe for his technical comment.