Accidental closing and correct use during force
If you study the sakhome.com you will find information at different places about
accidental closing and correct use.
The Swiss Army Knife spring for the slip-joint construction is advanced and it can be made to have additional contact areas or parts that can help for
preventing accidental closing. Lock to prevent this does not have to be a liner that supports the tang. It can also be like the Wenger design with a push lock design to prevent accidental closing.
On the picture you can see two giants in the evolution on a larger professional outdoors design.
It is unavoidable during force with push and turning motion that the function may
close in. That is called accidental closing and the result may be injury or damage.
It is not possible to turn a flat head screw design without pushing towards it. Because it is a slip-joint
design and the support is on the back of the function it is unavoidable that the function will close in where it is not supported. With practice it is possible to have a rather secure turning without a lock because the design of the construction with the tang,
rivet and support is balanced as best possible.
The dimension on the slip-joint spring follows the size of the function itself and for what can of use it is intended.
At some point a locking mechanism must be made to prevent accidental closing and best performance. Wenger had already made push lock designs on the 85mm knives from the early 1980s and Victorinox has made different
additional parts to avoid accidental closing on their knives in history.
The large Ranger Wenger knives incorporated the push lock design because it is unavoidable. The correct use for turning
a screw must involve a pushing with the hand if not the screwdriver will slip out of the track and you get problems.
Swiss Army Knives got precision in the assembly, riveting, slip-joint
spring. The Wenger spring is very advanced to able to take the push lock design. When you push it will enter the correct angle and be locked into the spring, rivet and construction.
liner lock for the Victorinox flat screwdriver is very interesting and it is made exactly for all the correct reasons.
better understand the reasons for locking mechanisms i have made some new pages lately: