Help identifying French leather machine - splitter or edge/strap thinner?

[Spike76]

Hi all, I found this hand-crank machine for sale and I'm trying to identify what it actually does before deciding whether to buy it. Plate marked "United Shoe Machinery de France - Paris", with a model reference that looks like "UP.639" (hard to read exactly, photo attached). Seller dated it to roughly 1915, and suggested it may have been used by a cobbler, glove-maker, or leatherworker — but wasn't certain themselves.

What I'm trying to figure out: is this a full-width leather splitter (reducing thickness across a whole skin/piece), or is it built for thinning/paring the edge or width of narrower bands/straps specifically?

The mechanism: a blade/disc engages into a slot on a lower wheel, and a second slot is visible further along on the same lower wheel — possibly suggesting different width settings. Photos of this detail attached.

Any help identifying the exact function would be much appreciated — including whether the blade is a standard/replaceable part or something proprietary to this model.

[Cumberland Highpower]

YARN | None of you dumb-asses knows? | Full Metal Jacket (1987) | Video clips by quotes | c621edbe | 紗

[alfredleatherworks]

To me, it looks like a kind of skiving or creasing machine. It’s not a piece I’m familiar with though, and I’ve tried doing a reverse image search to find something similar with no luck. A very cool find and a unique piece though!

[Digit]

(French) Wikipedia mentions it in present time and there's a website, so the company seems to still exist. Their website doesn't seem fully functional though: http://www.usmfrance.fr/

Maybe you could send them a message?