My estimate is it is a vintage wire / line dispenser, as the cam follower yoke would move as unspooling ribbon from a spindle mounted between the centers as material came off.
It could have been multi-purpose and have done wire, twine, etc.
I have seen some similar devices in general appearance used for that.
Since it lacks articulation mechanisms to wind, it logically would dispense from spools, unless this is only part of a mechanism, that actually used the squared ends to spin material onto a spool.

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Everett