For those who like to do research from primary sources, perhaps listings of Sheaffer patents would be useful. I'll offer a few now, more to follow. Readers are welcome to add more. I can incorporate those into the core post.
- 1934 Plunger Filler https://www.google.c...ved=0CHYQ6AEwCQ
- 1919 Pencil Mech: https://www.google.c...ved=0CDcQ6AEwAA
- 1938 Sheaffer (not Wahl!) Ink Shut Off: http://www.google.co...epage&q&f=false
- 1935-7 More ink shut off? http://www.google.co...epage&q&f=false
- 1932. Platinum Tipped Nib (and claimed improvement in ink flow) https://www.google.c...ved=0CD4Q6AEwAQ
- 1945 clip https://www.google.c...d=0CEkQ6AEwAzgK
- Ridged grip on a low line pencil https://www.google.c...ved=0CG8Q6AEwCA
- 1935 Feed for sacless Sheaffers https://www.google.c...ved=0CEUQ6AEwAg
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