I'm getting back into beekeeping after about a 30 year hiatus. My father ran an apiary that grew to over a hundred colonies with pollination services, honey, etc. in the 1970s. My brother and I moved hives for the pollination services, helped with the extraction of honey, and of course, helped assemble frames, supers, etc. I'm now re-establishing a backyard apiary, and am gradually growing my hobby. The woodenware (frames) I've purchased (and inspected on line) from a variety of vendors differs in one potentially substantial way from what I remember about the frames of my youth.
Specifically, the frames I remember had one 'V' shaped side and one 'Flat' side for each end piece. As you assembled the frames, you'd make them so that, for example all the 'V's were pointing away from you on the right side, and towards you on the left side. This allegedly allowed easier separation of frames that were propolized in place.
I don't see anyone manufacturing frames with that feature. Does anyone have any recollection of that design feature? Was it patented by a firm now no longer in the woodenware business? Could it potentially be of value to beekeepers at present? If it was patented, has the patent lapsed so that this could be adopted as a feature by current woodenware manufacturers?