초록 ▼

A curved backing insert is held in a backrest frame and adjustable to conform to the spine of a person leaning against the backrest. The backing insert comprises at least one elastic bow having a first end supported by said frame, a second end vertically spaced from said first end, and an intermedia

A curved backing insert is held in a backrest frame and adjustable to conform to the spine of a person leaning against the backrest. The backing insert comprises at least one elastic bow having a first end supported by said frame, a second end vertically spaced from said first end, and an intermediate vertex portion including a vertex. First stressing means are adjustable to move said second end so as to change the height and curvature of said bow. Second stressing means are adjustable to adjust said vertex relative to said first and second ends.

대표청구항 ▼

A backrest comprising (a) a backrest frame, (b) a housing fixedly mounted on the frame, (c) a curved backing insert held in the backrest frame and adjustable to conform to the spine of a person leaning against the backrest, the insert comprising an elastic bow having a lower end fixedly supported in

A backrest comprising (a) a backrest frame, (b) a housing fixedly mounted on the frame, (c) a curved backing insert held in the backrest frame and adjustable to conform to the spine of a person leaning against the backrest, the insert comprising an elastic bow having a lower end fixedly supported in the housing, a second end vertically spaced from the lower end and an intermediate vertex portion defining a vertex, (d) a first stressing means comprising a first reel rotatably mounted in the housing and a first flexible tension element having respective ends connected to the first reel and to the second end, the tension element defining a chord of the curved backing insert and being adapted to be wound on, and unwound from, the first reel for moving the second end relative to the lower end so as to change the curvature of the backing insert, (e) a second stressing means comprising a second reel rotatably mounted in the housing and a second flexible tension element having respective ends connected to the second reel and to the vertex portion, the second tension element defining a chord of the curved backing insert and being adapted to be wound on, and unwound from, the second reel for moving the vertex portion relative to the lower and second ends, (f) a drive shaft rotatably mounted in the housing, (g) clutch means mounted in the housing and operable for selective coupling of the first and second reels to the drive shaft, (h) first retaining means adapted to cooperate releasably with the first reel to hold the first stressing means in an adjusted position, and (i) second retaining means adapted to cooperate releasably with the second reel to hold the second stressing means in an adjusted position, the adjusted positions of the first and second stressing means maintaining the curved backing insert conformed to the spine of the person leaning thereagainst.