I just found a pair of old hub skewers in my tool box. They have to be from the 70's since all that stuff was acquired no later than 1979.
The clamp end has a black curved arm and the round end is marked as follows:
PINO INT. LTD. DETROIT
The PINO and the DETROIT are curved to fit the 13mm diameter end cap.
The rods look like ti to me. Strange wound springs (not tight).
The adjusting cap has two nylon screws at 180 degrees.
Can identify these skewers.
Thanks,
Jim Kerr
New Haven, CT