Abstract: In a mechanical extending device of a seat, a seat mounting plate limiting structure, a backrest hinge shaft, and a first connection rod hinge shaft are arranged on a seat mounting plate; a leg assembly is mounted to a front of the seat mounting plate; a rear upper end of the seat mounting plate is hingedly connected to the backrest mounting rod. The backrest mounting rod, the backrest support rod, the first connection rod, the seat mounting plate, the third connection rod, the second connection rod, the leg assembly are hingedly connected to each other. The second connection rod is arranged with a first support to support a load on the front of the seat mounting plate at a sitting position and a TV position. A second support is arranged on the third connection rod and is limited by a second support mounting groove of the fixing plate.

Abstract: In a mechanical extending device of a seat, a seat mounting plate limiting structure, a backrest hinge shaft, and a first connection rod hinge shaft are arranged on a seat mounting plate; a leg assembly is mounted to a front of the seat mounting plate; a rear upper end of the seat mounting plate is hingedly connected to the backrest mounting rod. The backrest mounting rod, the backrest support rod, the first connection rod, the seat mounting plate, the third connection rod, the second connection rod, the leg assembly are hingedly connected to each other. The second connection rod is arranged with a first support to support a load on the front of the seat mounting plate at a sitting position and a TV position. A second support is arranged on the third connection rod and is limited by a second support mounting groove of the fixing plate.

Abstract: An electric seat rack, including a driving assembly, a seat frame support assembly, a backrest assembly and two mechanical extension units symmetrically arranged on the left and right, the backrest assembly being hinged to the seat frame support assembly, each mechanical extension unit comprising a leg-foot assembly and a transmission rod. The two leg-foot assemblies are installed on two sides of the seat frame support assembly and are respectively hinged to one ends of the corresponding transmission rods, the other ends of the transmission rods are hinged to the backrest assembly by backrest transmission rod hinge shafts; two ends of a driving rod are respectively connected to the two leg-foot assemblies; the seat frame support assembly comprises two quadrilateral support frames symmetrically arranged on two sides and a connecting assembly for fixing the two quadrilateral support frames into one. The backrest assembly includes a backrest frame and backrest connecting components.