Patent ID: 7147282

Claim:
A chair, comprising: seat support structure; a seat assembly supported by said seat support structure; a backrest assembly, comprising: a generally U-shaped member having a pair of end portions; a backrest supported by said U-shaped member; and a backrest depth adjustment mechanism connecting at least one of said end portions to said seat support structure for generally rectilinear relative movement between said U-shaped member and said seat support structure, said depth adjustment mechanism including a selectively actuable backrest depth position lock mechanism connected between said U-shaped member and said seat support structure, wherein said backrest depth adjustment mechanism further comprises: a stationary portion connected to one of said end portions and said seat support structure; and a movable portion connected to the other of said end portions and said seat support structure, said movable portion selectively movable with respect to said stationary portion whereby a backrest depth position of said U-shaped member and said backrest with respect to said seat assembly may be adjusted; and a main spring connecting said stationary portion and said movable portion, said main spring normally biasing said movable portion toward said stationary portion.