Welcome to our project...

       This project is a catalog of all known preWWII pinball machine related patents, listed by the U.S. Patent Office's         patent numbers and final patent issue date.

        The U.S. Patent Office holds information about these machines by their manufacturer's patent numbers, including
    artwork, information on who designed each machine and when, and possibly repair diagrams for some early EM             machines and their parts.

         Art has given us information on how to access the USPTO website to find patent numbers by date and year
    using this website - http://www.uspto.gov/web/offices/ac/ido/oeip/taf/issuyear.htm. Here are his instructions on how
    to search the USPTO website for pinball machine patent information...

        Since the patents appear to have been issued every seven days (52 times per year), you can find a search starting
    point using the approximate issue date as in the following example...  If 3200 patents were issued in the year in question,     and July 1 was the approx issue date, then 3200/52 x 26 (the numerical week nbr)=1600 which when added to the             starting number for the year gives you the median number to start your search. If you know the date of issue (which is         sometimes shown), then determine the numbers limited to that date, and narrow your search to them. I usually enter
    about ten numbers in sequence with a space between in the USPTO quick search, and go back and forth between the         resulting list with the "images" and my browser back button. Keep in mind that most pins were only covered by the
    "Design" patent when the were released to the market, as these could be had in a month or two, with the full patent             process taking 1 to 3 years or more to be issued.

        Keith has given us another great search method for use when you know the company or designer's name...

        This URL below can be edited for keywords and used to go directly to a company or designer's patent holdings list.
     For example, the link below searches for designer Lyn Durant's (United Mfg.) patents from between 1935 and 1946.
    You can copy the entire link to your browser and edit out 'durant' and put in the keyword you want to use, and to
    search by date, you can edit out '1935' and add your starting date, and edit out '1946' and add your own ending date.