US Patent 7887138 Integrally formed base arrangement of an office chair

An integrally formed base arrangement of an office chair, and more particularly, a base arrangement integrally made by plastic material, comprising: a) a middle axle seat; b) a first U-shaped pivotal seat perpendicular to the middle axle seat; c) a claw member having a plurality of arched supporting arms extending in the shape of claws from the external rim of the middle axle seat upward; d) a base frame disposed at the top of the supporting arms of the claw member, an annular groove being positioned at the surface of the base frame; e) two second U-shaped pivotal seats symmetrically formed at both sides of the bottom of the base frame; and f) two hand rest supports extended from both sides of the base frame and the claw member outward, thereby creating a connection surface directed upward at the external end thereof. In this way, a convenient and rapid assembly of components of the office chair is ensured. Moreover, a stable structure is achieved.