||An assisted-opening knife is a type of knife which uses an internal mechanism to open the blade from a closed position when slight pressure is applied to the thumbstud or other finger actuated device. When the knife is in the closed position, the blade is held in place by means of 1 or 2 torsion bars. As the user applies manual pressure to the thumbstud to open the knife, a mechanism such as a torsion bar moves along a track in the liner and rotates the blade into the open position.
Although commonly confused with switchblade knives, there is a difference. A switchblade can be opened by means of pushing a button traditionally. Conversly, an assisted-opening knife must have some pressure applied to the blade at the thumb knob or fingeractuator. By definition, because the blade does not open by the push of a button or force of gravity, the assisted opening mechanism is normally not considered a switchblade. Once the knife has been opened about one-quarter of the way (45°), the mechanism opens the knife the rest of the way.
Many folding knives feature spring assisted opening to make one handed draws easy and fast. Several knife manufacturers include spring assisted opening mechanisms in their line of knives. J&L carries brands such as Smith and Wesson and Taylor Schrade Brand to name a couple.
To see a new law that was enacted to cover the differences described above please follow this link:
Bill SB 274, clarifies the definition of a one-hand opening knife so they are not wrongly classified as switchblades. Bill SB 274 clearly states: For the purposes of this section, switchblade knife means a knife having the appearance of a pocketknife and includes a spring-blade knife, snap-blade knife, gravity knife or any other similar type knife, which can be released automatically by a flick of a button, pressure on the handle, flip of the wrist or other mechanical device, or is released by the weight of the blade or by any type of mechanism whatsoever. Definition of Switchblade knife does not include a knife that is designed to open with one hand utilizing thumb pressure applied solely to the blade of the knife or a thumb stud attached to the blade, provided that the knife utilizes a detent or other mechanism that (a) provides resistance that must be overcome in opening the blade, or (b) biases the blade back toward its closed position. In order to ensure that only legitimate one-handed opening knives are covered, SB 274 narrows the language to only allow knives to fall under the exemption from the switchblade law if that one-handed opening knife contains a detent or similar mechanism. Such mechanisms ensure there is a measure of resistance that prevents the knife from being easily opened with a flick of the wrist. Moreover, a detent or other mechanism is prudent and a matter of public safety as it will ensure that a blade will not inadvertently come open.