Unique (antique?) locking slipjoint, please help identify

[iandh]

I found this very strange slipjoint when digging through some of my late grandfather's tools. I've never seen anything like, but then again I haven't been around that long. I was hoping maybe one of the old timers (or maybe "well seasoned knife aficionado" is a better term ) aroud here could help with ID.

At first I thought the little hook at the blade base was for prying or something, as it looks like a bottle opener. It was way too small though. After playing with the knife, I realized it was a locking mechanism. There is a loose sliding pin inside, mounted across a slot in each liner. When you close the knife tip down and give it a shake, the pin slides into the blade cutout, locking it shut. To open the knife, you flip it tip up (when closed), then give it a little shake, and press down on the blade and release. The blade is slightly spring loaded, and pops up out of the knife body slightly, to allow you to pinch the blade out into the open position.

At first when I found the knife, I was very confused about how to open it, becase there is no fingernail notch. This is actually a very novel mechanism, it operates a lot like those magnetic catches that you find on entertainment center doors, where you push in and the door pops out a little to you can grab the edge to open it. In this case though, it acts to lock the blade shut, as well as allowing the knife to be unfolded.

The only marking of any kind on the knife is "PAT NO." and some unreadable patent numbers beneath.


Kind of a neat "el cheapo" celluloid pattern on the scales, reminds me of a guitar pickguard.

Here's a view of the sliding pin inside the handle

This shows the blade in the closed and locked position

This is after you have pushed down and released the lock, with the blade sprung up in the ready to pinch position

 

[Tsujigiri]

I think you'd have better luck with this in the traditional section.

 

[KennyB]

I don't have any idea what they're called, but I once had one of these that was just discreet stainless steel. I think my dad had been given it as a gift at a seminar he attended for his old company. He said it had a "trick-lock", and I can tell by the photos and the description that it's exactly the same. Only, with mine you didn't need to shake it to get the latch to drop, you just had to hold the right end up in the air to get the latching mechanism to drop, thus the "trick lock".

 

[yablanowitz]

Generally just called a trick knife. Imperial made a lot of them with imitation pearl handle scales. I like the little things just because you don't have to risk breaking your thumbnails to get them open as long as you know how. I've seen a couple that someone tried to force and ruined, though.