Your lockblade folding knife should have a thumbstud, thumb"hole", thumb "disk" or similar push-thingy, so long as the "thingy" is attached directly to the blade (versus on the grip and linked up via a gearbox of sorts). It should not have a spring that does ALL the opening (yes, the Kershaw Ken Onion series seems to be OK). And finally, the blade needs to have at least some tendency to stay closed in the pocket or whatever bias a "bias towards closure" or "detent" (discussed in more detail later in this chapter).

As long as it's got all that, and the vast majority (including all eight knives discussed at the bottom of this document) do, it cannot be "declared a gravity knife or switchblade" even if you can snap it open with relish .

Spring Assisted Knife Laws
Legal Definitions:

Switchblade

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.
Assisted-Opening Knife / Spring-Assisted Opening Technology

A spring-assisted knife is a knife that when you push on the thumb stud to open it a spring takes over and propels the blade open. Spring-assisted knives make a great alternative to automatic knives. A Spring / Torsion assisted knife is a type of knife which uses a spring 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. A/O knives are Assisted - Opening which are also Spring - Assisted knives.

US Assisted Knife Law
CALIFORNIA is the basis of all law due to it being typically the hardest and most progressive

California State Senator Betty Karnette of the 27th District is the author and who is responsible for Bill SB 274 and the legalization of Spring Assist Knives.

Senator Karnette realized that Spring Assist Knives are extremely functional tools by law-abiding citizens and that these knives serve an important utility to many knife users, as well as firefighters, EMT personnel, hunters, fishermen, and others who utilize one-handed opening knives, then the prohibition of such items is obstruction to justice & complete disregard to US law.

Spring Assist Knives are intended to save lives while an EMT, Firefighter, or Law Enforcement Officer is trying to get you out of an automobile accident or any other viable problem. They have saved skydivers lives that had to cut parachute lines. They have saved countless fishing poles when a line is needed to be cut. They are also essential to handicap individuals whom happen to have one arm. Special Thanks to Senator Betty Karnette is in order because if it were not for her we would loose more of our rights in this country and also not have tools that are lifesaving instruments.
LEGAL LAWS & STATE STATUTES OF CALIFORNIA


The rules on "what is a legal pocketknife versus a switchblade" are contained in Penal Code 653k. In it's entirety (current effective 1/1/2002):

653k: Every person who possesses in the passenger's or driver's area of any motor vehicle in any public place or place open to the public, carries upon his or her person, and every person who sells, offers for sale, exposes for sale, loans, transfers, or gives to any other person a switchblade knife having a blade two or more inches in length is guilty of a misdemeanor.

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, the blade or blades of which are two or more inches in length and 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. "Switchblade knife" does not include a knife that opens 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 has a detent or other mechanism that provides resistance that must be overcome in opening the blade, or that biases the blade back toward its closed position.
------------------------------------------------------------------------

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.
Read Senator Betty Karnette's exact words in a letter published to the Secretary of the Senate.

Published in the July 18, 2001 edition of the Senate Daily Journal on page 2070.

DRAFT - LETTER TO THE SENATE DAILY JOURNAL

July 5, 2001

Mr. Gregory Schmidt
Secretary of the Senate

Dear Greg:

The purpose of this letter is to express the Legislature’s intent in enacting my SB 274, which makes amendments to Penal Code Section 653k.

Section 653k makes it a misdemeanor to make, sell or possess upon one’s person a switchblade in California. The statute was enacted in 1957 and provides a length definition of a switchblade knife. In 1996, AB 3314 (Ch. 1054) an exemption was created for one-handed folding knives. Recently, there has been concern that the language of the exemption is broadly read to apply to knives that are essentially switchblades, but are designed to fall under the language of the exemption.

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 (no matter how slight) 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.

Although some one-handed opening knives can be opened with a strong flick of the wrist, so long as they contact a detent or similar mechanism that provides some resistance to opening the knife, then the exemption is triggered. These knives serve an important utility to many knife users, as well as firefighters, EMT personnel, hunters, fishermen, and others utilize one-handed opening knives.

The exemption created in 1996 was designed to decriminalize the legitimate use of these extremely functional tools by law-abiding citizens. SB 274 is not intended to interfere with those knife owners and users. The amendments to Section 653k accomplish this important purpose by establishing more objective criteria for determining whether a knife meets the intended exemption to the switchblade law.

Sincerely,
BETTY KARNETTE
Senator, 27th District