Tim et al,
Here is one of the sources to which I referred earlier:
Jack H. Tod
1985 "Insulator Patents, 1880-1960," privately printed by:
Jack H. Tod
3427 N. 47th Place
Phoenix, AZ 85018
This is pretty good collection of patent cards. He stated there were 3,000+
patents, of which 695 had cards showing the kind of detail insulator
collectors would find useful. I am not sure how many of those are in the report, but
there are a lot of them. The drawings are pretty good for identification.
Ron May
Legacy 106, Inc.