Ring binder having interlocking ring tips

A ring binder for use in holding loose-leaf pages, the ring binder comprising:

• an elongate body extending along a longitudinal axis;
• rings for retaining loose-leaf pages, each ring including first and second ring members extending from the elongate body, the first and second ring members being moveable relative to one another between a closed position in which the first and second ring members together form a substantially continuous, closed loop for allowing loose-leaf pages retained by the ring to be moved along the ring from one ring member to the other and an open position in which the first and second ring members form a discontinuous, open loop for adding or removing loose-leaf pages from the ring;
• and
• a retaining system operable to selectively and releasably hold the first and second ring members of at least one of the rings in the closed position, the retaining system comprising first and second interlocking formations adjacent ends of the first and second ring members, respectively, of said at least one ring, the first and second interlocking formations being selectively moveable relative to one another between a retaining position in which the retaining system holds the first and second ring members in the closed position and a non-retaining position in which the retaining system does not hold the first and second ring members in the closed position,
• wherein the interlocking formation of the first ring member includes a recessed region and a first projection, the first projection extending generally upwardly relative to the recessed region at a position located distally on the first ring member relative to the first recessed region, and the interlocking formation of the second ring member includes a vaulted region and a second projection, the second projection extending generally downwardly relative to the vaulted region at a position located distally on the second ring member relative to the vaulted region, wherein the first projection is received in the vaulted region and the second projection is received in the recessed region when the interlocking formations are in the retaining position, and wherein the interlocking formations are configured so that movement of the interlocking formations relative to one another in the direction of the longitudinal axis of the body is blocked when the interlocking formations are in the retaining position.