Fig.2  1939 UK Patent 514513 Fig.4  Blackbird BT200/82 (topfill), 60 (topfill), 81 (converted to bulbfill), 60 (made as bulbfill) Return to top of page Back Reprinted from the Journal of the Writing Equipment Society (UK), July  2004 Home Fig.3  Advertisement, September 1938 Fig.1 Blackbird Topfiller BT200/82 Fig.5  Blackbird BT200/60 bulbfiller Fig.6  Early topfiller with removable bush Figs.7a,b  Cross-sections of the original and modified topfill mechanisms Fig.8  Later topfill mechanism Fig.9 X-ray of improved topfiller