Yes, the old flat leaf spring traps employed sliding safety rings to give you some peace of mind when setting - that said, the angle of the spring often means that they slide when the trap fires so I wouldn't trust them implicity - not with those toothed jaws looming ...
I no longer have the 2 traps shown here, but I thought that you might like to see something a bit different to Fenn and Kania traps
OTC