An unusual 1880 patent Cross stylographic pen

This unprepossessing Cross stylograph arrived along with a group of early Cross nibbed fountain pens -- the centerpieces of the lot. Upon closer examination, however, this conventional-looking stylo turned out to have some unusual features.

The writing tip is typical enough on the outside, but the gold needle is stepped, with a thicker body and a thinner end. Needles are normally made from wire of constant thickness. Then there is the oddly fastened retaining wire through the hard rubber shaft.

Once the end cap at the other end of the barrel is unscrewed, there is something else out of the ordinary: a metal ball. Trying to figure out how the pen worked, I pushed down on the needle to see if it was spring-loaded. It was, but not in the usual way where the needle moves and the central shaft stays fixed. Here the entire central shaft was spring-loaded, and when it was pushed back into the barrel, the little metal ball at the end was pushed off its seat as well. Clearly they formed a single assembly, with the ball hooked to the central shaft via an attached loop and hook.

What was this supposed to accomplish? My initial thought was that this was some sort of early valve design, where the pressure of writing would move the needle back and allow the ball valve to admit just enough air to keep the ink flowing. Such overelaborate valve designs are found in many early fountain pen patents of this same era, though few actual examples are known. In this case, however, the possibility was immediately ruled out by the length of the needle -- not long enough to protrude, nor to be pushed back in use -- and the excessive stiffness of the spring. Fortunately, this guesswork did not have to be relied upon, since the pen bears good clear patent imprints for June 29, 1880. Issued on that date to A. T. Cross was US patent 229,305.

Several variations are shown and described, with the same central concept. The actuation of the mechanism is not via the needle, but rather via the ball -- which is a knob, not a valve. The patent explains that the arrangement "provides convenient means for clearing the fine tube at the lower end of the ink-chamber, or at the point of the pen, from interfering sediment or ink deposit, without the necessity, as heretofore, of either opening or partially opening the ink-chamber". The inks of the 1870s and 1880s were not always optimally free-flowing, hence this attempt to create a pen with a self-unclogging mechanism -- a "tube-clearing spindle", in the parlance of the patent. In case of a stoppage, the end cap was to be unscrewed and the little ball pulled and allowed to snap back into place. Whether this would have squirted ink out the nozzle is not noted in the patent, though it seems all too probable.
Cross patented numerous stylographic pen mechanisms, not all of which are known to have been produced. This is one that I do not recall having seen before.