Legal Definition of Switchblade Knife:A switchblade (also known as automatic knife, switch, or, in British English flick knife) is a type of knife with a folding blade that springs out of the grip when a button or lever on the grip is pressed. There are two basic types: side-opening and out-the-front (OTF). A side-opening knife's blade pivots out of the side of the handle (in the same manner as an ordinary folding knife). An out-the-front knife's blade slides directly forward, out of the tip of the handle. Many OTF (out-the-front) knives work with a dual-action mechanism that enables the user to extend and retract the knife in one press of the finger, with no cocking or priming action. However, some OTF (out-the-front) knives are single action, and require the user to manually retract the blade. A wide variety of blade designs may be found on switchblades, but the most common is the Italian stiletto style seen often in movies. However, the switchblade should not be confused with the butterfly knife (balisong), assisted-opening knife, or the non-automatic stiletto.
Overview of Switchblade Knife Designs:There are two basic types of switchblades, side-opening / folding switchblades and OTF switchblades (Out-The-Front or telescoping). A side-opening knife's blade pivots out of the side of the handle (in the same manner as an ordinary folding knife, except with the press of a button). An out-the-front knife's blade slides directly forward, out of the tip of the handle. There are two types of OTF (out the front) knives: double action and single action.
Double action OTFs allow the user to extend or retract the blade with the press of a sliding button. Spring tension in these knives is actually provided by the movement of the button, which makes them much safer to carry since they will not open accidentally. However, the extra force the spring requires can also make intentional opening more difficult.
Single Action OTFs require the user to retract the blade manually and compress the spring. Because they often use a lever to compress the spring, stronger springs can be used. This makes them open more vigorously than the double-action type, and allows them to achieve tighter lock-up.
The varieties of button or lever mechanisms, blade locks, safeties, single or multi-blade and spring configurations are so numerous that a complete listing is virtually impossible. Several books, periodicals and newsletters have been written to aid in cataloging for collectors.
The word stiletto is sometimes used in English to refer to a switchblade however a stiletto is a short knife or dagger, with a long slender blade of various designs and does not necessarily insinuate that it is an automatic switchblade. Switchblade Stilettos should not be confused with or the non-automatic stiletto linerlock or lockback version folding knives.
The side-opening switchblade should not be confused with the butterfly knife also called the Balisong or Batangas
The side-opening switchblade should not be confused with the Assisted-Opening Knife also referred to as the A/O Knife, Torsion Assist Knife, Assisted Knife, Spring Assist Knife, Spring Assisted Knife, Quick Release, Quick Draw, Alternative Automatic and the Semi-Auto. An assisted-opening knife is a knife that when you push on the thumb stud to open it a spring takes over and propels the blade open. Assisted knives make a great alternative to automatic knives. An assisted-opening knife is a type of knife which uses an assisted mechanism behind the blade. They open by the ambidextrous thumb stud on the blade with a slight bit of pressure. They are commonly confused with switchblades, but have one main difference. While a switchblade can be opened usually with the push of a button within the handle, the user of a spring-assisted knife must apply slight pressure to the thumb stud and the spring/torsion assisted mechanism does the rest. Once the knife has been opened about one-quarter of the way (45°), the mechanism will open the knife the rest of the way. In basic essence the main difference between a full-auto and an assisted-opening knife is the external trigger, and the internal power source. A full-auto uses a spring to power the blade and a button to release the blade from the handle. By contrast, a assisted-opening knife uses a pre-tensioned crescent shaped steel bar to provide the power, and the user is required to depress the blade in some way - either by the use of a thumb stud or some protrusion on the blade itself. Because the user’s hands are clear of the sharpened portion of the blade during deployment they are far safer than a traditional knife where the users hand must come into forcible contact with the blade. Small differences admittedly, but differences nonetheless; and the law is all about detail. Thus a assisted-opening knife is not prohibited in the US, UK, or Canada in the same way that a full-auto is and logically this makes sense - ANY knife (or ANY other tool for that matter) can be dangerous in the wrong hands IRRESPECTIVE of configuration, size, ease of use, or geometry. This amounts to criminal abuse of what is just a tool let's not forget. When Kershaw revealed the Chive at the Shotshow in America during 2003, people were amazed at the simplicity of it’s' design. After all, how could someone pack so much technological advancement into such a small package? Acclaimed American custom knife maker Ken Onion is the man behind this wonderful new design. But perhaps the origin's of Mr. Onion's marvel need a little more exploring. Kershaw's little Chive has proved to be quite a controversial showpiece. So what's the secret behind it's incredibly easy-to-use blade deployment mechanism...Some have questioned the legality of carrying something that opens so readily, yet the law is quite clear. Switchblade Automatic knives are defined as an auto as 'operated by a button or any other device attached to the handle'. Of course, the Chive has neither a spring nor any device attached to the handle, relying instead on a pre-tensioned steel bar to provide the power (an invention pioneered by Blackie Collins on the Meyerco Power Assisted range). It also features an extended tang that protrudes from the handle, another idea developed from Kit Carson's Flipper system found on his Columbia River M16 models. Combine the two ideas and ... wow! It's fast alright, but still within the limits of acceptability. Some argue that this just exploits a loophole within the law, but I would point out that this is just extremely clever conceptual design and it should be appreciated as such. Kershaw promote the safety aspect of the design, and irrespective of whether it is fast or not, you can't escape the fact that the whole idea is to provide a tool which is easily and readily available for use with maximum safety in mind.
Switchblades from the 1930s to the 50s had a high amount of hand craftsmanship and are very collectible. Recent mass production methods tend to yield cheaper knives with thinner materials and less detail work. However, there are a fair number of knife companies and custom makers who build high-quality automatic knives for military, emergency personnel, and for knife collectors. Some famous automatic knife manufacturers include Microtech Knives, Gerber Legendary Blades, ProTech, Benchmade, Dalton, Boker/Magnum, Severtech, Spyderco, and Piranha. Then there are the Italian manufacturers famous for the classic stiletto style switchblade. Included among these are Frank Beltrame, whose family has been making automatics for over 50 years, and AGA Campolin, another family concern that has been in the business for some 60 years.
A new variation of the switchblade is a Dual-Action design that allows the user to manually open the knife as though it were a manual (and legal) folding knife. Often, the trigger for such knives is hidden in a grip panel, these are commonly referred to as Hidden Release or Hidden Scale, The user is required to move the scale away from the body of the handle or squeeze or twist the handle in a certain fashion, or is hidden in some other manner such as the Colt M-16-K, Boker Plus Tactical Action 2 Linerlock, or the Smith & Wesson SWAT series.