Not really Schwinn, just fit them, called Darwin pedal adjusters from the fifties or older. The centerline distance is 1 1/2" These are bolted for 1/2x20 pedal threads. What brand bike would they go on and what distance do you need? Crank/ pedal threads match up. These do not look too hard to duplicate in different sizes, or thread.
9/16 would be best, but I could make half inch work. I’m putting them on Sugino tandem triple crankset. My son has short legs so for now I think we would need a 3 inch reduction give or take. So, I don’t think yours will be quite short enough yet.
I like the Tandemseast or the Ride2 shorteners, but I was hoping to find something that wasn’t over a hundred/pair.