Soft close ring binder mechanism with mating ring tips

A ring binder mechanism for retaining loose-leaf pages, the mechanism comprising:

• a housing;
• hinge plates supported by the housing for pivoting motion about a pivot axis relative to the housing;
• rings for holding loose-leaf pages, each ring including first and second ring members, the first ring member being mounted on a first hinge plate and moveable with the pivoting motion of the first hinge plate relative to the second ring member so that in a closed position a free end of the first ring member joins with a free end of the second ring member and in an open position the free end of the first ring member separates from the free end of the second ring member, each ring member including a longitudinal centerline;
• the free end of the first ring member having an interlocking configuration having a first shape and the free end of the second ring member having an interlocking configuration having a second shape adapted to interengage with the interlocking configuration of the first ring member to block movement of the first and second ring members relative to each other in all directions transverse to the longitudinal centerlines of the ring members when the ring members are in their closed position;
• and
• a control structure supported by the housing and movable relative to the housing, the control structure resisting separation of the free ends of the ring members when the ring members are in their closed position.