Here is my list of Esterbrook patents. The link goes to a European database site. Click on Original Document for the full patent description. Enjoy!
Please make corrections or additions.


<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US1800425&F=0> Patent No 1800425 </A> Pen 1931 <br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US1832077&F=0> Patent No 1832077 </A> Pen 1931 <br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US1847163&F=0> Patent No 1847163 </A> Penholder 1932 <br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US1896152&F=0> Patent No 1896152 </A> Fountain Pen 1933 <br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US1918239&F=0> Patent No 1918239 </A> Fountain pen 1933 <br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US1939649&F=0> Patent No 1939649 </A> Fountain pen 1933 <br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US1939753&F=0> Patent No 1939753 </A> Fountain pen 1933 <br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US1975775&F=0> Patent No 1975775 </A> Pen and pencil clip 1934 <br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US1999177&F=0> Patent No 1999177 </A> Fountain pen 1935 <br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2037699&F=0> Patent No 2037699 </A> Pen and method of making the same 1936 <br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2156302&F=0> Patent No 2156302 </A> Blank for and method of manufacturing steel pens 1939 <br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2159002&F=0> Patent No 2159002 </A> Manufacture of metal stock 1939<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2159003&F=0> Patent No 2159003 </A> Manufacture of writing pens 1939<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2168311&F=0> Patent No 2168311 </A> Blank for and method of making writing pens 1939<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2218536&F=0> Patent No 2218536 </A> Fountain pen 1940<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2228250&F=0> Patent No 2228250 </A> Manufacture of writing pens 1941<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2292381&F=0> Patent No 2292381 </A> Fountain pen feed 1942<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2304832&F=0> Patent No 2304832 </A> Ink feeding means for writing pens 1942<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2320369&F=0> Patent No 2320369 </A> Manufacture of metal writing pens 1943<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2367539&F=0> Patent No 2367539 </A> Pen and reservoir attachment therefor 1945<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2367540&F=0> Patent No 2367540 </A> Pen and fountain attachment therefor 1945<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2390541&F=0> Patent No 2390541 </A> Writing implement 1945<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2430023&F=0> Patent No 2430023 </A> Writing implement 1947<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2500833&F=0> Patent No 2500833 </A> Fountain pen 1950<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2513380&F=0> Patent No 2513380 </A> Writing instrument 1950<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2601846&F=0> Patent No 2601846 </A> Writing pen assembly 1952<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2621629&F=0> Patent No 2621629 </A> Inkwell 1952<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2631569&F=0> Patent No 2631569 </A> Fountain pen with positioning means for the ink sac thereof 1953<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2678635&F=0> Patent No 2678635 </A> Writing equipment 1954<br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2681276&F=0> Patent No 2681276 </A> Pen nib alloy <BR>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US2758568&F=0> Patent No 2758568 </A> Ink wells 1956 <BR>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US3040708&F=0> Patent No 3040708 </A> Fountain pens 1962 <BR>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US3041693&F=0> Patent No 3041693 </A> Clip mountings for fountain pens 1962 <br>
<a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=US3434159&F=0> Patent No 3434159 </A> RECORDER HAVING STYLUS PRESSURE ADJUSTMENT ASSEMBLY 1969 by <b>Venus Esterbrook Corp</b>


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Also here is a Conway Stewart patent for the button filler of the Esterbrook relief 2-S <a href=http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=GB297194&F=0> Patent No GB297194</A> Improvements in or relating to fountain pens 1928-09-20

Looks like a god list Antonios, Unfortunately the espacenet site is down for maintenance right now. I'll cross reference with my list in the morning. Love those early 30's patents for the V-clips.

Best-
Brian

I just looked now and the site was busy. But all that is too cool! Thanks.

Yes it did not work from 12-1 but the site is available now.

Antonios,

Thank you for so generously sharing this information. I appreciate the time and effort you put into your contributions.

I find this a very useful resource. I was pleased to see that the #444 ("hockey puck") inkwell base was one of the patents on your list. I enjoyed seeing a cross-section of its structure.

Cheers,
Laura