Patent ID: 7632137

Claim:
A power adapter comprising: a main body of cylindrical shape, a top of the main body defining a recess, and an annular sidewall enclosing the recess; a rotation-proof component which is received in the annular sidewall of the main body and which defines a rotation-proof portion extending into the recess; a plug rotatably mounted in the recess, a side of the plug defining at least one rotation-proof recess; and, a main shell having a platform formed at an inner side thereof for supporting the main body thereon, the rotation-proof component further having two fixing portions extending oppositely from two ends of the rotation-proof portion and extending out of a bottom of the annular sidewall and bending towards the platform for being sandwiched between the bottom of the annular sidewall and the platform; wherein the rotation-proof portion is elastically pressed against the plug as the plug rotates in the recess, and is then released into the rotation-proof recess for restraining the plug from reverse rotation.