Patent attributes
A chair backrest mechanism, a chair frame and a chair are provided, including a back supporting member, a hip and leg supporting member, a swing traction unit, a linkage member and an auxiliary traction member. The hip and leg supporting member includes a leg supporting portion and a hip supporting portion. The back supporting member is movably connected to the hip and leg supporting member by the swing traction unit. The auxiliary traction member is pivotally connected to the swing traction unit and includes a first pin joint portion and a second pin joint portion, the first pin joint portion is pivotally connected to the hip supporting portion, the second pin joint portion is pivotally connected to a first end of the linkage member, and a second end of the linkage member away from the second pin joint portion is pivotally connected to the back supporting member.