Need help identifying this Unusual single blade no nail pull w/locking mechanism

[Bigduck1]

Hello Knife Dudes and Dudettes!
I have an unusual Single blade folder that looks like it may be an Imperial? It has a Tang stamp with the following(If I read it correctly);
PAT. NOS.
2037943 Knife with Handle Casing was filed on 3-25-35 by Otto Ernst Stiehl and Jr. Ernst Lohr. And patented Apr. 21, 1936
2170537 Imperial Refinement of Stiehl and Lohr’s Patent filed July 6, 1938 by F. A. Mirando and Henry Vossler. And patented Aug. 22, 1939
**both of the above Patents are from the 1935-38 time frame.


What is unusual about this knife, and something I haven’t come across yet, is that it doesn’t have a nail pull on the blade. It has some sort of a locking roller/pin mechanism that latches to a hook on the tang portion. To unlatch the blade for opening, you need to push down on top edge of blade and then tilt/slant the knife downwards. That causes the rolling pin mechanism to roll out of the hook to release. You can then extend the blade out like normal. To put the blade back down to store it, fold the blade in, push down on the top edge of blade and then tilt the knife back towards you. That then causes the rolling pin mechanism to roll back into the hook to lock it down. It took me forever to figure out how to open this blade up!! Once you get the hang of it, it seems pretty clever. I find it odd that neither of the above Patent numbers are for that pin/lock mechanism.??? Does anyone have any additional information on this pocket knife? I can not find anything that looks similar. I will attach some photos that may help. TIA !!

[Rockingkj]

Yes Imperial “trick knife” of at least that’s what we always called em. Have seen them in a variety of colors and some with advertising. Old guys liked to hand em to youngsters and enjoy watching them trying to open the knife. Simple when you know the “trick”. I did once see a better quality version marked “Keen Kutter”. Interesting knives.

[ThatWeirdKnifeGuy]

Alot of people recognize them as trick or mystery knives. It is indeed from Imperial, and that time frame, likely a few years later, possibly up to the late 60's, I believe. This is a screenshot of an old Imperial catalog (forgot where I got it from, apologies).

[Bigduck1]

It sure was “tricky” for me Do you know if there was a Patent for that mechanism?

[Bigduck1]

Thank you both for the info!

[Mumbleypeg]

I used to have a couple of those. Tormented the grandkids with them, until they figured out how to open them. I passed at least one of them off several years ago in the annual AAPK POS knife exchange, but I may still have one somewhere.

Ken

[orvet]

I believe there was a patent on that mechanism. The patent in the OP is probably the patent for that mechanism.

[New_Windsor_NY]

Hello.....

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