If you have never visited the US patent database this is patent might be a good introduction. Searches of the database for various apiculture related patents can be entertaining. I expect few have made money from most of the listed patents. The scanned pages of the patent are available for most recent patents. Visit: http://patent.womplex.ibm.com/details?patent_number=5571247 to see Patent 571247 :Self containing enclosure for protection from killer bees Searches for bee and hive hive and tool honey and frame yeild various patents. The database goes back to 1971. Happy surfing.