Marketing Inventions To the Editor: My letter is in response to your article entitled "Carpenters of Invention," (JLC, 1/90). I framed the cartoon of the article and hung it on the wall next to my patent document. I too am a professional carpenter with a labor saving invention that I now have a patent on. My progress, though, has stalled. I do not have the time to manufacture and market like the inventors featured in your article. Perhaps you or a company who might have responded to your article might be of some help. How can the "carpenters of invention" be connected with the companies that are willing to manufacture and market these new products that the industry desperately