A folding door system comprising:
- a concealed hinge comprising:
- a first hinge block having a slot formed therein and defining a first sliding portion,
- a second hinge block having a slot formed therein and defining a second sliding portion,
- a first linkage having a first connection pivotally secured to the first hinge block and a second connection slidably and pivotally secured within the second sliding portion, and
- a second linkage pivotally connected to the first linkage and having a third connection pivotally secured to the second hinge block and a fourth connection slidably and pivotally secured within the first sliding portion,
- a first frame and a second frame, each frame having a pair of opposed major faces, a reference line extending perpendicularly between the opposed major faces, and a pair of opposed side faces, wherein the distance between the opposed major faces defines a width,
- wherein the first hinge block is mounted to one of the side faces of the first frame and the second hinge block is mounted to one of the side faces of the second frame,
- wherein the first sliding portion has a first section that forms a first angle relative to the reference line of the first frame, wherein the first angle is up to 115 degrees,
- wherein the second sliding portion has a first section that forms a second angle relative to the reference line of the second frame, wherein the second angle is up to 115 degrees,
- wherein, upon sliding the second connection from a first position to a second position in the first section of the second sliding portion and sliding the fourth connection from a first position to a second position in the first section of the first sliding portion, the second frame is rotated from a substantially closed position to a partially open position about an equivalent pivot axis,
- wherein the first frame comprises a first plane parallel to and coincident with the first major face of the first frame, and a second plane parallel to and coincident with the second major face of the first frame,
- wherein the first and second sliding portions are arranged such that, as the second frame rotates from the substantially closed position to the partially open position, the equivalent pivot moves from a first position between the first and second planes to a second position between the first and second planes,
- wherein the first sliding portion comprises a second section extending from the first section at a third angle relative to the first section of the first frame, and the second sliding portion comprises a second section extending from the first section at a fourth angle relative to the first section of the second frame,
- wherein the first and second sliding portions are arranged such that, sliding the second connection from a first position to a second position within the second section of the second sliding portion and sliding the fourth connection from a first position to a second position within the second section of the first sliding portion, rotates the second frame from the partially open position to a substantially open position where the opposed major faces of the second frame are substantially perpendicular to the opposed major faces of the first frame,
- wherein the third angle is greater than the first angle relative to the reference line,
- wherein the fourth angle is greater than the second angle relative to the reference line, and
- wherein the equivalent pivot axis moves away from the first plane as the second frame rotates from the substantially closed position to the partially open position, and wherein the equivalent pivot axis moves towards the first plane as the second frame rotates from the partially open position to the substantially open position.