I’ve been researching patents and trademarks for about ten years. Many times I’ve thought I’ve seen it all but then I’d come across something totally unexpected. One example of this was coming across a web page about modern fractional patents. For historic reasons (explained on this page) there are old patents issued between 1812 and 1836 where the patent number contains a fraction. I was quite surprised to find “modern” examples of the same thing. The page I found is no longer around but was authored by Jim Davie, apparently the unofficial historian at the patent office who has since retired.
The fractional patents Jim Davie found were listed on this page: http://patentmodelassociation.com/fractional.html I found that a subset of these are available online at the uspto and an overlapping subset is available in the Hathi Trust gazette collection. I also found two more fractional patents not in Jim’s list available at uspto.gov by analyzing the USAPat cumulative index
Jim Davie’s Fractional Patents
- RE 1,217 ½
- USPTO: https://pdfpiw.uspto.gov/.piw?idkey=NONE&docid=RE01217H
- RE 1,242 ½
- Not available at Hathi or USPTO
I believe this is available on microfilm at the Public Search Facility.
- 2,712,152 ½
Not on uspto.gov but I scanned a copy from microfilm at the Public Search Facility.
- 3,262,124 ½
- Hathi: http://hdl.handle.net/2027/wu.89049556301?urlappend=%3Bseq=329
Also not on uspto.gov but I also scanned a copy from microfilm.
- D 90,793 ½
Russ’ Fractional Patents
- 1400 ½
- D1093 ½
- USPTO: https://pdfpiw.uspto.gov/.piw?idkey=NONE&docid=D001093H