It is a law that a civil weapon cannot fire when overall length of weapon is less than 31 inches. That means that all AK’s with barrels above 23 inches and folding stocks must have stock-activated safety. This mechanism in latest Saigas is the following:
A special blocking plate is placed on the left wall of the receiver. This plate interacts with standard safety axis by forward end and with special cut in folding stock axis by it’s back end.
When safety is disengaged, the plate is in back position, AK trigger mechanism works in standard way, but this plate’s back end gets in the stock’s axis cut, preventing stock from being folded. When safety lever is engaged, the blocking plate goes forward and it frees stock axis, so the stock can be folded. When stock is folded, you can’t push safety lever down, because the plate can’t go back, as the stock axis has only one cut – corresponding stock unfolded position.
View from the top of the receiver, receiver cover off.
1 – Stock
2 – Receiver
3 – Blocking plate
4 – Safety axis
5 – Safety lever
Img.1 Stock in working position
Img.2 Stock folded
Before year 1999 there was another “old style” blocking mechanism that engaged independent safety placed on stock folding button. But that mechanism had poor protection from instant and reversible cutting off by not 100% law-abiding citizens. Just like the new one, actually.
If you have any other questions – please feel free to ask.