Thanks for posting the diagram, Frank!
After reading the patent, it seems to me the flywheel and cord were meant to rotate the mold smoothly and
rewind it. Pulling a cord once is a quicker, easier, one-step way to rotate the mold than turning it by hand - a single person could set it in motion then put the bubble into the mold. Or does the bubble have to go in first? I'm a little confused about the bars, and the mold itself. Do the bars slide over the glass, forming it that way, or do they grip it, so that the centrifugal motion of the machine expands the glass out between the bars?
Of course a patent does not mean it was ever used.
Yes, I've been thinking about that lately. There must be a lot of patents out there that were never used for commercial production.
One thing I've been wondering about is patents for glass formulas. It seems like many of them are sort of wishy-washy, saying the formula contains (four particular ingredients) plus additional ones, at the maker's discretion. This one, for example: http://www.google.com/patents?id=jpNpAAAAEBAJ&printsec=abstract&zoom=4&dq=1629648
It says, "My invention is applicable to any sand and soda ash mixture with or without other ingredients and the addtion of litharge, borax and manganese is optional." Two specific formulas are give at the end - is the patent, then, just for those two formulas?
I think you've finally got it right, multiple fingers with oval openings on the top of them.
Tom, thanks for checking in ... it's always nice having another glassblower's ideas, and further confirmation that the distorting/skeleton mold Cummings describes could have been used on the pitcher in the OP. No doubt the bosses could have been made using other means, but my original question about skeleton molds seems to have been answered.
"Final finishing with hand torches and glaziers could have fire polished these areas then." Any idea when the use of hand torches began? What's a glazier?
BTW, do you all remember the vase that apparently has the same design as the pitcher? I FINALLY heard from the owner a week ago that it is smooth on the inside, with no depressions behind the bosses. Perhaps that means it wasn't made using the same type of mold, or maybe with the thicker glass there that Tom was talking about they just don't show up because that part wasn't really blown into shape, as the thinner glass was.