Patent ID: 8998322
Filing Date: 2015-04-07
Classification: A47C

Abstract:
1. A reaction force mechanism for a backrest of a chair, the mechanism comprising: a base member supported on a leg; a back support member coupled by a rotation shaft to the base member to be able to recline and support the backrest; a seat support member to which a seat is mounted; a weight-dependent reaction force mechanism for moving the seat support member in a lifting direction in relation to the reclining of the back support member; and a reaction force spring for applying a spring force for returning the back support member to an original position, wherein the reaction force spring is disposed in a lateral orientation between the back support member and the base member, wherein the weight-dependent reaction force mechanism couples a front portion of the seat support member to the base member so as to be rotatable with a link interposed therebetween, and couples rotatably a back portion of the seat support member with a lever link portion extending diagonally upward and forward from the rotation shaft, wherein the link supporting the front portion of the seat support member inclines toward a front rather than the lever link portion, wherein the lever link portion at THE front portion of the back support member rotates so as to lift the back portion of the seat support member diagonally backward and upward by the reclining operation about the rotation shaft, and wherein the front portion of the seat support member is lifted while raising the link coupled to the front portion of the seat support member.