Text: Click around this site http://www.patentec.com/data/class/Classes.html and it will lead you to definitions of each class/subclass.  (Note don't bother with the classes prefixed by "D"= deleted)  Write down the class/subclass number for what interests you then go to http://www.uspto.gov/patft/index.html and on quick search plug in the numbers and scroll the dropbox to "Class" - "Subclass".  A results page will pop up eventually.  Remember that it is a good idea to use Subclass No.'s or results could number in the thousands. Also patents prior to 1975 are only found by either Patent No. and/or Class No.

See Also:

Source: