How does a switchblade work?

Answer 1

Basically there are two distinct styles of "switchblade" or automatic knife. ?[http://www.nicnac.net/media/1afronttxt.jpg Here are some examples of different styles.] The most common one opens by the blade pivoting from the frame as most normal folding knives do but the blade is propelled or deployed by pushing a button or lever on the frame (or handle) of the knife which releases a coil or flat (leaf or kicker) spring that forces the blade to deploy and then the knife locks open. The locking and unlocking mechanisms vary greatly. There are several different types of locking and unlocking mechanisms used on most switchblade automatic knives. The most simple is simply using the same button to unlock and close the blade that is used to deploy the blade. There are also "liner locks" which, as the name suggests) uses a portion of the knifes frame to lock the blade open by springing behind the blade when it is fully opened. To close a liner lock simply push the liner back against the frame and close the blade. Italian knives sometimes use a lever to deploy and unlock the blade much as the button locking system but there are several other locking systems used on these kinds of knives. Italian locks include the "picklock" which unlocks the blade by prying the spring lock bar up with a thumbnail or other object which releases a small pin which is part of the blade and unlocks the knife for closing. A more modern version of this is the swivel bolster lock. The locking mechanism is the same as the picklock but the bolster of the knife on the button side swivels and is used as a lever to push the locking bar open. Then there is the "back lock" which means the spring on the back of the knife engages with a notch on the blade when the blade is deployed and locks open. There is a detent toward the back of the knife where a person can push down on the rear of the backspring, which is pinned into the knifes frame in the center, which raises the front of the spring and unlocks the blade. The second type of switchblade automatic knife deploys the blade straight out the front by means of a spring inside the frame. The blade is deployed and unlocked using the button or a form of liner locking mechanism. These are called single action front opening knives or OTF (out the front) knives. There are also double action front opening knives which both deploy and retract the blade by using a series of springs and locking ramps on the inside of the knife. The front opening knives are NOT known as "stilettos" as some people mistakenly refer to them. A "stiletto" has a long thin blade and can be used on many types of knives from fixed blade to automatic.