Patent ID: 9713383
Date: 2017-07-25
CPC Classifications: A47C

Claim:
1. A ball chair comprising: a cushion having a ball shape; a seat having a bearing portion supporting the cushion, and a connecting portion connected with the bearing portion and provided with an engaging recess and at least a through hole communicated with the engaging recess; a back having an engaging block inserted in the engaging recess and having at least two relatively larger protrusions spaced from each other, at least one relatively smaller protrusion located between said at least two relatively larger protrusions, and at least one threaded hole provided at said at least one relatively smaller protrusion and corresponding in position to the through hole of the connecting portion of the seat; and at least one threaded fastening member having a head and a body extended from the head, inserted through the through hole of the connecting portion and engaged in the threaded hole of the engaging block for fixing the back to the seat, wherein the engaging recess has at least two relatively larger cavities for accommodating said at least two relatively larger protrusions, and at least one relatively smaller cavity located between said at least two relatively larger cavities for accommodating said at least one relatively smaller protrusion; said at least one through hole is located in said at least one relatively smaller cavity.