Patent ID: 8602496
Filing Date: 2013-12-10
Classification: A47C

Abstract:
1. A chair with a back-and-forth moving backrest comprising a seat, a backrest including a lower end that is separated from the seat, and a rotating mechanism connecting a side of a back end of the seat to a side of the lower end of the backrest, wherein: the rotating mechanism comprises a first rotating rod, a second rotating rod, a first rotating joint and a second rotating joint; the first rotating rod includes upper and lower ends and a middle segment connecting the upper and lower ends; upper and lower ends of the second rotating rod each include a circular hole; the first rotating joint includes a middle segment, an inner segment, and an outer segment; a first mounting seat is connected and fixed at one of the sides of the lower end of the backrest, and the inner segment of the first rotating joint is inserted into the first mounting seat; the second rotating joint includes a middle segment, an inner segment, and an outer segment; a second mounting seat is connected and fixed at one of the sides of the back end of the seat, and the inner segment of the second rotating joint is inserted into the second mounting seat; the inner segment of the first rotating joint includes a first groove and a first shaft hole, the upper end of the second rotating rod is positioned in the first groove, a first shaft rod is inserted into the first shaft hole and the circular hole in the upper end of the second rotating rod; the inner segment of the second rotating joint includes a second groove and a second shaft hole, the lower end of the second rotating rod is positioned in the second groove, a second shaft rod is inserted into the second shaft hole and the circular hole in the lower end of the second rotating rod; the upper end of the first rotating rod is sheathed with the outer segment of the first rotating joint, and the lower end of the first rotating rod is sheathed with the outer segment of the second rotating joint; the upper end of the first rotating rod includes a first center circular hole, and the lower end of the first rotating rod includes a second center circular hole; the first rotating joint includes a first center hole, and the second rotating joint includes a second center hole; the rotating mechanism comprises a first screw rod and a second screw rod, the first screw rod extends through the first center circular hole and the first center hole, and is screwed in a threaded hole in the first mounting seat, and the second screw rod extends through the second center circular hole and the second center hole and is screwed in a threaded hole in the second mounting seat, wherein the upper end of the first rotating rod can rotate relatively to the first screw rod, and the lower end of the first rotating rod can rotate relatively to the second screw rod; a line extending between the first center hole and the first shaft hole is parallel with a line extending between the second center hole and the second shaft hole, and a line extending between the first center hole and the second center hole is parallel with a line extending between the first shaft hole and the second shaft hole; and during rotation of the rotating mechanism relative to the backrest and the seat, the vertical state of the backrest is maintained relative to the seat.