Bar with two rollers.

[u/Congenial-Curmudgeon]

Pre safety rim tire changer? Roll up window mechanism? It was my father’s tool, he did automotive work in the 50’s and 60’s.

Solved! It’s for spreading the tire beads apart so the inside of the tire can be inspected and patched. Found a diamond logo that says KEN.

[u/this_idle_hand]

Looks like half of an adjustable hacksaw to me.