weird brass trim rings

[jeffmoss26]

Got these with a lot of locks off ebay, and I have ZERO idea what they would be used for. Surely someone will know!

[Josephus]

My entirely random guess is they are just a faceplate/retainer ring for a sort of rim cylinder. Slide the lock through the ring from the front and screw in place. The bible interfaces with that 'U' feature to give some resistance to brute force torque.

Here is a Yale I have that may show what I mean:

[jeffmoss26]

Yes, I tried that with a Corbin of mine and it almost fit lol

[Altashot]

Strange collar. Never seen one of those. I get what you guys are saying but If it IS indeed what those rings are for, I find a big flaw with it right away. The purpose of a ring it to spin free as to not twist the cylinder in the event that a pipe wrench or similar device does get a hold of it even though its tapper and/or thin edge deter that. Those rings in question here, supposedly hold the rim cylinder the right way? That would now means that the cylinder WOULD turn WITH the collar and could defeat, let's say, a Panic bar. It is no longer free spinning...IMO, not a good idea. On the other hand, maybe when everything it tighten down, it grabs the inside of the door shell, aluminum or steel, and prevents turning the collar itself...? ...I doubt that.

M.

[nozza36]

I know what it is ! barbies toilet seat lol

[GWiens2001]

Nah, Barbie's skinny backside would fall right through. You are aware that she maintains her figure using plastic surgery, right?

But back to the topic. Wondering if those rings are for retrofitting rim cylinders onto doors already set up for mortises or deadbolts, and the manufacturer was not concerned with pipe wrenches.

Gordon