patent searching

Does anyone know of a good website (or other resource) for searching U.S. patents by number. The few sites that I have found date back to 1971 at the earliest. I need years between 1920 and 1950.

Thanks,

William Scott

patents by number. The few sites >that I have found date back to 1971 at the earliest. I need years between 1920 and 1950.

Chicago's Harold Washington Library )the main branch of the public library) has patent records on microfilm and in bound volumes. If you know the number, it's pretty easy to look up the drawings on microfilm.

I don't know if they'll do searches over the phone, I've always done them in person.

good luch,

Hi William

Thank you, Diane and Sheila for responding to my query. What a great help it will be when these are searchable on line!

Until then, I have found a useful page for using the patent numbers to establish the earliest possible date that an object was made. The page lists the first patent number issued for each year since the 1800's.
http://www.pangea.com/~rock/oldtools/misctools/patentdates.html

I may still try to make it up to the Chicago library, but mostly because I miss Chicago.

Thanks again!

William Scott

Try
http://www.patents.ibm.com/ibm.html