Updated December 18, 2010, from the printed books. Note: Pennsylvania is the only state of which the criminal code is not available online.
Pennsylvania - Pa. C.S.A. 18.908. Prohibited offensive weapons. (a) Offense defined.--A person commits a misdemeanor of the first degree if, except as authorized by law, he makes, repairs, sells, or otherwise deals in, uses, or possesses any offensive weapon. (b) Exception.-- It is a defense under this section for the defendant to prove by a preponderance of evidence that he possessed of dealt with the weapon solely as a curio or in a dramatic performance..., or that he possessed it briefly in consequence of having found it or taken it from an aggressor, or under circumstances similarly negativing any intent or likelihood that the weapon would be used unlawfully. (c) Definition.--As used in this section "offensive weapon" means... any... metal knuckles, dagger, knife, razor or cutting instrument, the blade of which is exposed in an automatic way by switch, push-button, spring mechanism, or otherwise...
Pennsylvania case law - Pa. C.S.A. 18.908. Prohibited offensive weapons:
Testimony of police officers unsupported by any legal authority, subjectively stating that "Cobra" knives sold by defendant did not serve any common lawful purpose and that, as an officer he feared that, because young adults were attracted to unique look of knives, the knives posed a great threat to society and had to be prohibited under prohibited offensive weapons statute, was insufficient to prove a prima facie case against defendant for selling prohibited offensive weapons (1996)
Although waved in a crowded barroom, defendant's folding knife with a seven-inch blade, which was purchased at a sporting goods store to be used for hunting and fishing, as not an implement for infliction of serious bodily injury which served no common lawful purpose within meaning of this section (1980)
Thirteen-inch butcher knife which defendant carried while he was charging up a crowded street and threatening to kill another person had a common, lawful purpose and thus was not an implement for infliction of serious bodily injury which served no common lawful purpose, within provision of this section defining offensive weapons, and defendant was not guilty of prohibited offensive weapon (1980)
"Wyoming Knife" which consisted of metal handle with two finger holes incorporating two cutting blades, one facing outward and the other inward, was hunting implement which had "common lawful purpose," and thus such knife was not "offensive weapon" for purposes of this section proscribing repairing, selling, dealing in, and using of possessing prohibited offensive weapons (1979)
Where opening knife required lock to be released, and once lock was released blade could be exposed by flip of wrist, knife did not have blade which could be "exposed in an automatic way" within contemplation of this section (1979)
Legislature's use of "otherwise" after "switch, push-button, [and] spring mechanism" in phrase of this section which describes as such weapon the blade of which is exposed in "an automatic way by switch, push-button, spring mechanism, or otherwise," shows that by "otherwise" legislature referred to knives that were opened by some sort of mechanism which is not a "switch," "push-button," or "spring" mechanism but still a mechanism (1979)
Blade of knife that must be exposed by flick of wrist is not exposed "as if mechanically" or "by itself," as such language is used in this section (1979)
A simple kitchen knife is not a "prohibited offensive weapon" (1978)
Thirty-inch knife found in possession of defendant while in a high crime urban area in early morning hours had no common lawful purpose and was a prohibited weapon under this section enumerating certain types of weapons and including "or other implement for the infliction of serious bodily harm which serves no common lawful purpose" (1975)
Knife having its blade folded in handle which, by pressing pushbutton and by operation of gravity or flip of the wrist, is opened, is a knife which opens in an automatic way and was prohibited by 18 P.S. Â§ 4419 (repealed). 1958 Op.Atty. Gen. No. 86.
In prosecution of inmate for possession of knife, evidence which established that knife was found in tightly locked cabinet, accessible only by using key which was in exclusive possession of defendant, was sufficient to establish that defendant was in possession of weapon (1983)
Absent proof that knife, which did not have blade "exposed in an automatic way," had no common lawful purpose, Commonwealth's evidence in prosecution for for possession of prohibited offensive weapon failed to prove essential element that such knife was "offensive weapon" (1979)
Evidence sustained conviction of possessing prohibited offensive weapon, a butcher knife with seven-inch blade which was wrapped in paper and was found in back pocket of defendant who was in subway late at night in high-crime area (1978)
In prosecution for possession of prohibited offensive weapon, wherein knife was not admitted into evidence, evidence was insufficient to prove possession of weapon coming with this section's definition of "offensive weapon" (1977)
Pennsylvania case law - Pa. C.S.A. 18.909. Instruments of crime:
Hunting knife, which was eight and one-half inches long with five-inch blade was not within purview of this section defining instruments of crime as anything specially made or specially adapted for criminal use (1978)
Defendant possessed an "instrument of crime" so as to be guilty of a misdemeanor in the first degree where possession of pocketknife, which was a device commonly used for criminal purposes, was with intent to employ knife criminally and was under circumstances not manifestly for appropriate lawful uses (1976)
A paring knife is not a "criminal instrument" in the absence of evidence of intent to employ it criminally which would sustain a prosecution for possession of an instrument of crime.
* * *
Title 18 Â§ 908. Prohibited offensive weapons. (a) Offense defined.--A person commits a misdemeanor of the first degree if, except as authorized by law, he makes repairs, sells, or otherwise deals in, uses, or possesses any offensive weapon.
It is a defense under this section for the defendant to prove by a preponderance of evidence that he possessed or dealt with the weapon solely as a curio or in a dramatic performance, or that, with the exception of a bomb, grenade or incendiary device, he complied with the National Firearms Act (26 U.S.C. 5801 et seq.), or that he possessed it briefly in consequence of having found it or taken it from an aggressor, or under circumstances similarly negativing any intent or likelihood that the weapon would be used unlawfully. This section does not apply to police forensic firearms experts or police forensic firearms laboratories. Also exempt from this section are forensic firearms experts or forensic firearms laboratories operating in the ordinary course of business and engaged in lawful operation who notify in writing, on an annual basis, the chief or head of any police force or police department of a city, and, elsewhere, the sheriff of a county in which they are located, of the possession, type and use of offensive weapons. This section shall not apply to any person who makes, repairs, sells or otherwise deals in, uses or possesses any firearm for purposes not prohibited by the laws of this Commonwealth.
(c) Definition.--As used in this section, the following words and phrases shall have the meanings given to them in this subsection:
"Firearm." Any weapon which is designed to or may readily be converted to expel any projectile by the action of an explosive or the frame or receiver of any such weapon. "Offensive weapons." Any bomb, grenade, machine gun, sawed-off shotgun with a barrel less than 18 inches, firearm specially made or specially adapted for concealment or silent discharge, any blackjack, sandbag, metal knuckles, dagger, knife, razor or cutting instrument, the blade of which is exposed in an automatic way by switch, push-button, spring mechanism, or otherwise, or other implement for the infliction of serious bodily injury which serves no common lawful purpose.
(d) Exemptions.--The use and possession of blackjacks by the following persons in the course of their duties are exempt from this section:
Police officers, as defined by and who meet the requirements of the act of June 18, 1974 (P.L.359, No.120), referred to as the Municipal Police Education and Training Law. Police officers of first class cities who have successfully completed training which is substantially equivalent to the program under the Municipal Police Education and Training Law. Pennsylvania State Police officers. Sheriffs and deputy sheriffs of the various counties who have satisfactorily met the requirements of the Municipal Police Education and Training Law. Police officers employed by the Commonwealth who have satisfactorily met the requirements of the Municipal Police Education and Training Law. Deputy sheriffs with adequate training as determined by the Pennsylvania Commission on Crime and Delinquency. Liquor Control Board agents who have satisfactorily met the requirements of the Municipal Police Education and Training Law.
Title 18 Â§ 912. Possession of weapon on school property. (a) Definition.--Notwithstanding the definition of "weapon" in section 907 (relating to possessing instruments of crime), "weapon" for purposes of this section shall include but not be limited to any knife, cutting instrument, cutting tool, nun-chuck stick, firearm, shotgun, rifle and any other tool, instrument or implement capable of inflicting serious bodily injury.
(b) Offense defined.--A person commits a misdemeanor of the first degree if he possesses a weapon in the buildings of, on the grounds of, or in any conveyance providing transportation to or from any elementary or secondary publicly-funded educational institution, any elementary or secondary private school licensed by the Department of Education or any elementary or secondary parochial school.
(c) Defense.--It shall be a defense that the weapon is possessed and used in conjunction with a lawful supervised school activity or course or is possessed for other lawful purpose.