Switchblade knife

A switchblade (also known as an automatic knife, pushbutton knife, ejector knife, switch, Sprenger,Springer,flick knife, or flick blade) is a type of knife with a folding or sliding blade contained in the handle which is opened automatically by a spring when a button, lever, or switch on the handle or bolster is activated. Most switchblade designs incorporate a locking blade, in which the blade is locked against closure when the spring extends the blade to the fully opened position. The blade is unlocked by manually operating a mechanism that unlocks the blade and allows it to be folded and locked in the closed position.

In 1954, Democratic Rep. James J. Delaney of New York authored the first bill submitted to the U.S. Congress banning the manufacture and sale of switchblades, beginning a wave of legal restrictions worldwide and a consequent decline in their popularity. In 1955, U.S. newspapers promoted the image of a young delinquent with a stiletto switchblade or flick knife with lurid stories of urban youth gang warfare, often featuring lower class youth and/or racial minorities.

Switchblade knives date from the mid-18th century. The earliest known examples of spring-loaded blades were constructed by craftsmen in Europe, who developed an automatic folding spike bayonet for use on flintlock pistols and coach guns. Examples of steel automatic folding knives from Sheffield England have crown markings that date to 1840. Cutlery makers such as Tillotson, A. Davey, Beever, Hobson, Ibbotson and others produced automatic-opening knives. Some have simple iron bolsters and wooden handles, while others feature ornate, embossed silver alloy bolsters and stag handles. English-made knives often incorporate a "pen release" instead of a central handle button, whereby the main spring activated larger blade is released by pressing down on the closed smaller pen blade.

In France, 19th-century folding knives marked Châtellerault were available in both automatic and manually opened versions in several sizes and lengths.Châtellerault switchblades have recognizable features such as "S" shaped cross guards, picklock type mechanisms and engraved decorative pearl and ivory handles. In Spain, Admiral D'Estaing is attributed with a type of folding naval dirk that doubled as an eating utensil. In closed (folded) position, the blade tip would extend beyond the handle to be used at the dining table. It could be spring activated to full length if needed as a side arm, by pressing a lever instead of a handle button. By 1850, at least one American company offered a .22 rimfire single-shot pistol equipped with a spring-operated knife. After the American Civil War (1865), knife production became industrialized. The oldest American made production automatic knife is the Korn Patent Knife, which used a rocking bolster release.

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