automatic knife

A switchblade (also known as switch knife, automatic knife, pushbutton knife, ejector knife, flick knife, Stiletto, flick blade, or spring knife (Sprenger, Springer)) is a pocketknife with a sliding or pivoting blade contained in the handle which is extended automatically by a spring when a button, lever, or switch on the handle or bolster is activated. Virtually all switchblades incorporate a locking blade, where the blade is locked against accidental closure when the blade is in the open position. It is unlocked by a mechanism that allows the blade to be folded and locked in the closed position.
During the 1950s, US newspapers as well as the tabloid press promoted the image of a new violent crime wave caused by young male delinquents with a stiletto, switchblade, or flick knife, based mostly on anecdotal evidence. 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.

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