Concealed hinges from Weber Knapp Co., Jamestown, N.Y, (www. weberknapp.com), help hide high-end refrigerators in kitchen cabinetry. The refrigerator maker Sub-Zero Freezer Co., Madison, Wis. (www. subzero.com), tapped Weber Knapp for the design when a previous concealed hinge proved unsatisfactory. The four-bar hinges are just 0.75-in. high and support a 107-lb door with its shelves and bins loaded. Another model of the hinge works on 36-in.-wide, 143-lb. doors for the company's latest "stealth" refrigerators.
The hinges don't protrude above door surfaces and are invisible with the door closed. They prevent door sag and remain within spec after 300,000 cycles, double the number for typical refrigerator hinges. A standard full-open position of 105° can be changed in the field to 90° for different kitchen layouts. A self-closing feature creates a bias toward the closed position over a 30° angle.