I bet the transcripts of the Klien patent suit has the answer in it somewhere. Someone with a frame with that patent number on it may be able to reference the patent, I bet there is an annotation on that in the files that I would think would reference it.
From my memory, Shook (designer of the Weyless pedals and seat post) did one, as seen in an image in Competitive Cycling news rag from the early 70's.
I can remember the image, but not the when.