Patent ID: 8602493

Claim:
A chair with a hip-shaping seat comprising: a base with an assembling portion; a chassis with a front end and a rear end, and a direction extending from the front end to the rear end being defined as X, between the front end and the rear end being connected a bottom surface and a top surface, the bottom surface being formed with an assembling portion assembled to the assembling portion of the base, and an inserting portion formed at the rear end of the chassis, on the top surface of the chassis being provided a pivot located at the front end and an arc-shaped rail located adjacent to the rear end, and the pivot being a section of a circle whose center is located at the position of the pivot, on the guiding rail being provided two slide blocks; a seat formed by two symmetrical seat members, on top of each of the seat members being formed an arc-shaped surface which has a lateral edge, so that, when the two seat members are assembled together along the lateral edges, the two arc-shaped surfaces cooperate with each other to define a seat space, each of the seat members being provided with an ear portion adjacent to one end of the lateral edge for insertion of the pivot of the chassis, and a pivot portion adjacent to another end of the lateral edge, each of the seat members being further formed on a bottom thereof with an assembling portion which is located adjacent to the lateral edge for assembling the slide blocks of the chassis; an adjustment rod including a rod portion and two positioning rings, the rod portion being formed with a clockwise thread, a counterclockwise thread, and a positioning section between the clockwise thread and the counterclockwise thread, each of the positioning rings being formed with a pivot to be pivotally connected to the pivot portion of the seat members and a threaded hole for insertion of the rod portion, in such a manner that the threaded hole of one of the positioning rings is screwed with the clockwise thread, and the threaded hole of another one of the positioning rings is screwed with the counterclockwise thread; and a chair back with a back portion and a fixing portion extending from a bottom of the back portion, in the middle of the fixing portion being formed a positioning slot extending in the direction X, the fixing portion being inserted in the inserting portion of the chassis, and the positioning section of the rod portion of the adjustment rod being restricted in the positioning slot.