BACK REST INCLINING APPARATUS FOR CHAIR

摘要

PROBLEM TO BE SOLVED: To attempt to perform cost reduction and to easily correspond to miniaturization by improving mechanical strength of a joint part which can be inclined forward and backward between an upper frame and a lower frame and eliminating restriction on the constitutional material of the part. SOLUTION: An upper holder 21 and a lower holder 25 are respectively mounted on an upper frame s for fitting a back rest plate and on a lower frame 6 and they are brought into slidable contact with each other so as to be able to incline only forward and backward by means of a recessed curved face projection-like joint part 21c formed on the lower end face of the upper holder 21 and a projected curved face channel-like joint part 25c formed on the top end part of the lower holder 25. On the other hand, A projected curve- like contact face of the top face of the lower end of a connection shaft body 30 which is passed through the upper and lower holders 21 and 25 up and down and is energized with a cylindrical rubber 36 and a recessed curve-like seat part 29 facing downward in the front and back direction of the back rest in the passed-through space 28 of the lower holder 25 are brought into freely slidable contact with each other only in the front and back direction of the back rest.