Mon Sep 09, 2013 4:41 am by DR2
MBI wrote:I think Riyame is right, it's to close off the back of the keyway so you can't insert a tool like the Peterson bypass tool for American padlocks, or the Silver Bullets for Master padlocks.
It could be something else, too. Sure, some lock companies might not advertise the difference between picking and bypassing and the pin might very well prevent the insertion of the Lockmasters and Peterson types of bypass tools...but it might be something a bit more rare. I don't know because I have never turned a key in one of these padlocks.
I do know that since the 1950s, so it is nothing new, French Revolier Handcuffs, the high security model, uses a very simple little disc (wafer) tumbler (single sided) lock to secure the double lock feature on them. On American handcuffs, you use the pin on the back of the key to set the double locks and they can be picked or inertia slammed into something to bypass. On the Revolier, the double lock is locked and unlocked with a small Yale key. This lock would be nothing to pick for a man with any number of improvised tools he could hold in his teeth or contort your wrists to get a position on. And while the Revolier high security cuffs are pickable, even if you are in them, they are more difficult to pick because of an anti-pick feature that is similar to that one up above. It is simply a pin that protrudes from the side of the plug, near the rear of it, and creates a slight drag on the plug that you can feel even when you have the proper key. They were written up in The Locksmith Ledger back in the 1960s, if I remember correctly, and the feature is described in the Patent for them. I don't know if that is what this is, but it looks like it.
"Any sufficiently advanced technology is indistinguishable from magic." ~ Arthur C. Clarke's Third Law of Prediction