I see it also covers a double bubbler system (see figure 2 in the patent). I doubt they can ever enforce this patent as in many areas of the US bongs are illegal. Even mentioning the word "bong" was trouble at one point.Hers the U.S. Patent for "Bong" circa 1977
http://www.google.com/patents?id=A4...tract&zoom=4&dq=bong#v=onepage&q=bong&f=false
The 1st bong I toked out of was a bamboo 1...& the 'bowl' was an inverted thimble with a hole punched in the top/bottom. The year was 1970 & I was living in Chicago at the time.
Of course, back then a 'lid' was $15 for Michoacan or Oaxacan...& $20 for Jamaican or Acapulco Gold. We didn't see much Hawaiian in Chi-town, but we did get some killer Thai-Sticks.