Patent attributes
A ring binder for retaining hole-punched pages comprises a housing, a pair of pivotable hinge plates received in the housing, and at least one pair of half ring members fixed to the hinge plates and moved between a closed position and an open position. Each of the half ring members comprises an anchoring portion fixed to a corresponding hinge plate, a transverse arm portion connected to the anchoring portion and extending outwardly in a transverse direction, an oblique arm portion connected to the transverse arm portion and extending obliquely and upwardly, and a curved portion connected to the oblique arm portion and extending upwardly and inwardly. In the closed position, upper ends of the curved portions of the pair of half ring members abut against each other in a face to face manner, and the opposite curved portions form an upwardly directed arc.