<html> <body> John & others, I just sent this to Roger Wheelock at Dampp-Chaser. Maybe he'll have something to say. Avery At 08:54 PM 4/30/2007, you wrote: <blockquote type=cite class=cite cite="">Paul, I looked at this last night. (<a href="http://www.uspto.gov/" eudora="autourl">www.uspto.gov</a>) It appears to be the only patent for a cover to be used in conjunction with a DC system. I didn't look everywhere, but this was one of the three patents I found for Dampp-Chaser Corp. Anyway, what this appears to be talking about is the older way of doing it with the mylar type plastic material. I think I installed only one of those, as it was right around the time that I started working full-time as a piano tech. The undercover in use now is speaker fabric. There is a possibility that there might be a patent pending. Maybe someone could contact Dampp-Chaser and find out. Or maybe someone from there will comment here on the list. There are a number of us who want to abide by the law, and it would be helpful to know exactly what that is. JF P.S. After reading the patent lingo, one thing I hope I never have to become is a patent lawyer. Ugh!  :-)  No offense to any of you who like that kind of thing. On 4/30/07, paul bruesch <tunergeek@gmail.com> wrote: <blockquote type=cite class=cite cite="">I found the Dampp-Chaser's patent online: <a href="http://www.freepatentsonline.com/6133519.pdf" eudora="autourl"> http://www.freepatentsonline.com/6133519.pdf</a> (you might have to create an account to look at the pdf, for some darned reason) According to the abstract, the under/back cover patent is for a "...moisture impervious aperture free sheet...".  In the detail of the patent write-up, under "Background of the Invention" it specifies "MYLAR or felt" (caps theirs) "... having a plurality of apertures or holes..." (which, to my mind, contradicts the abstract portion... but then again I'm not a lawyer.) So, what sort of fabric/material is Dampp-Chaser's under/back cover made of?  I'm not a rocket scientist, nor even a acoustic engineer, heck, I'm not even an RPT, but the idea of Mylar back/under cover on a piano sounds to me like it would sound a bit bizarre. Wouldn't it?? And wouldn't felt mute and muffle the sound?  (see previous disclaimers regarding my qualifications) I wonder what a "plurality of apertures or holes" means... several holes and/or apertures in the cover, or is that phrase intended to include an open weave like speaker cloth, being what it sounds like many techs are using. An open weave certainly has a "plurality of holes," but it would make a lot more better sense to say "open weave fabric." Please understand that I'm not trying to get around anyone's patent, or infringe on same... when the time comes I'll order the DC cover simply for the convenience of it, if for no other reason. My curiosity is piqued about this patent for a new way to use a piece of cloth... and I'd just like to understand it better. Judging from the amount of traffic generated by this topic, I don't think I'm alone. Paul Bruesch Computer Geek and PTG Associate, who typically plays by the rules but wants to understand them. And I don't run with scissors. </blockquote></blockquote></body> </html>