The supporting structure of the liner-lock is made of two liners to which the scales are clipped. The right sided liner is cut to obtain a laminated spring that butts up against the tang of the blade when the knife is in the opened position. That prevents the knife from closing. To release the lock the user must action the lockbar with his thumb. Other variants of the mechanism can feature a button that releases the lockbar. Also sometimes the left sided liner can be missing.
Similar to the liner-lock, the design of the frame-lock requires the scale and the frame to overlap. Therefore the lockbar is contained in the handle scale. For knives of big dimensions this is generally made from titanium to support the final weight. To release the frame-lock it is necessary to push off the spring in order to bring it back to its initial position and to free the blade.
Every back-lock system involves a rocker arm and a lever, with a protrusion that hooks up with an indentation on the upper blade’s tang. This lever is actioned by a spring, traditionally built in with the back spacer. Viper has reengineered the system with a spiral or coil spring placed in a notch between the scale and the liner. To close the knife you need to lower the rear part of the lever, which can be either positioned at the back or at the centre of the spine, by pressing with the thumb.
The slipjoint knives do not have a real block, but only a system that opposes a certain resistance to the closing of the blade, after which the blade is free to close.
Usually, the elastic element that contrasts the movement of the blade consists of a dorsal spring, similar to the one used on the back-locks, which is distinguished by the absence of the tooth used to hook the blade.
To close a slip joint, simply press on the back of the blade until the resistance of the spring is overcome.
The Action Stopper is a particular slipjoint system developed by Viper, in which the back spring is replaced by two springs, cut into the liners, the ends of which house a steel sphere each, and press laterally against the sides of the blade.
Compared to classic architecture, Viper's Action Stopper has the advantage of being invisible from the outside, leaving the back of the handle open, and to ensure a smoother rotation.
With the Automatic SAFE SYSTEM LOCK®, (A.S.L.S.) Viper takes safety a step forward. This patented system ensures that the knife is automatically locked during opening and unlocked manually with a simple finger movement. A small locking system applied on the liner lock engages the tang of the blade when opening making the lock solid and safe. Unlocking is done with a simple backward movement of the slide and opening of the liner.
All Viper fixed blade knives are supplied in combination with tough sheaths, either synthetic, Kydex or leather made, exclusively manufactured by Italian producers, to allow you to carry the knife with you easily and safely.
A leather sheath is combined with some “gentleman” knives, respecting a classic and more traditional aesthetic.