Ring binder mechanism

A ring mechanism for retaining loose-leaf pages comprises a housing (11), hinge plates (27a,27b), and ring members mounted (13) on the hinge plates for retaining pages on the mechanism. An actuating lever (15) is pivotally mounted on the housing for engaging the hinge plates and pivoting them to selectively move the ring members between an open position and a closed position. A travel bar (45) is operatively connected to the lever for selective movement between a position in which locking elements of the travel bar block the pivoting movement of the hinge plates and a position in which the travel bar allows the hinge plates to pivot. The lever is configured to deform when pivoting the hinge plates to close the ring members to delay movement of the travel bar and locking elements to the blocking position from the onset of pivoting motion of the hinge plates.