Many of you believe that the spring assisted knives are the same as the switchblades but in reality they are quite different from each other. A switchblade can be best described as being an "automatic opening" knife. Its usage is considered illegal in the United States. Further a switchblade can be opened through a spring that is released when the button present on the handle is pressed. In fact even most of the police and the military officials and their respective organizations have switched from the original "automatic" knives to the spring "assisted" knives.
As has been aforementioned a switchblade comes with a release button that is used for opening the blade. This actually means that the respective blade is fully released post the pressing of the button.
Whereas in the spring assisted knives there is only one button that has been designed for starting the blade that opens from the handle.