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 games 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.