Got an old pair in a box purchase the other day.  I found a picture on Google Image the other day but it did not pan out.  And now it is nowhere to be found.
I need a patent wizard.

They are cast and nickel? plated.  Different patent dates on the center swivel.
One says PAT'D Feb 11 1902.
Other says PAT'D Oct 27 1903.

You do not need to be a patent whiz to use the datamp.org website.  All you have to do is type in the patent date.

It is a jar wrench, not a piston ring compressor.

http://datamp.org/patents/displayPatent.php?pn=742238&id=15807

Maybe it was patented as a jar wrench, but based on the other tools in the box, it is clear that it was being used as a piston ring compressor.
Other tools included an old school piston pin installer (Snap-on S9005), sockets, 2 T bars, speeder, Milwaukee Tool & Forge, squeeze-type valve spring tool, tap and die set, wrenches, etc.
The old boy who owned it adapted it for his own use.
Probably stole it from the kitchen!

And I've seen piston ring compressors pretty much of that design.  Here's a modern example: https://jet.com/product/detail/7438c484171241c3a4a950d2c9b35bb6?jcmp=pla:ggl:b_nj_dur_gen_hardware_a2_b1:tool_accessories_a2_other:na:PLA_643009581_30054712702_pla-161721866940:na:na:na:2&code=PLA15&gclid=CIn1ueKkttACFVLcfgodAOgA-w&gclsrc=ds

Northwoods, sorry, but your spelling of stole is wrong.

the proper spelling is "borrowed"

The style that Bill posted are the only way to install some pistons on small engines, particularly two-strokes.  Some of my British motorcycles would also require the compressor to be removable from under the barrel.

I made a compressor band like that and used regular pliers to squeeze it - it worked well, but it would be nice to have the real tool.
Al

I used to use hose clamps on air-cooled VW rings*, where you had to remove the compressor tool after you slid the cylinder down over the rings.

I've done it, on a BMW motorcycle, with carefully applied pressure from fingertips (fingernails, actually), lubricated by plentiful blue air**; but it helped that the cylinders on BMWs were tapered at the bottom, so the ring fed smoothly into the cylinder diameter.

*Not my idea; I learned it from a book.
**Air reaches its maximum lubricity at about turquoise.  Additional cursing applied after that just gums things up; when the air reaches navy blue, it's time to quit for the day.

Though I had real ring compressors, I often used hose clamps on motorcycles.

I had used the wind down / wrap around style, then got a set of lid removers and love them!
I don't have a pic of them, they have their own drawer in the old snappy box.