Ring binder mechanism

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

• a housing that defines a housing interior,
• first and second hinge boards positioned in the housing interior and configured to pivot relative to the housing, the first and second hinge boards being pivotable between a closed position and an open position about a pivot axis,
• a plurality of pairs of semi-rings, each semi-ring including a first ring member mounted on the first hinge board and moveable with the pivoting motion of the first hinge board and a second ring member moveable with the pivoting motion of the second hinge board, the first and second ring members each being pivotable between a closed position and an open position and extending through an opening in the housing, and
• a travel bar moveable linearly with respect to the housing and the hinge boards between an open position and a closed position, wherein the travel bar is biased toward the open position, wherein the travel bar includes a push member extending upwardly from an end thereof that is positioned outside the housing interior, wherein when the travel bar is in the open position, pushing the push member in a first linear direction toward the housing moves the travel bar and the first and second hinge members from the open position to the closed position, wherein when the travel bar is in the closed position, pushing the push member in the first linear direction toward the housing causes the travel bar and the first and second hinge members to move from the closed position to the open position.