Safety Gear for Ultra-High Speed Elevator

Toshiba has developed a safety gear for elevators running at the rated speed of 1,000m/min. Safety gears for elevators running in the speed class of 1,000m/min use a friction material made of a fibre-reinforced compound material which has silicon nitride as a main ingredient to prevent deterioration of the friction material due to heat generated by friction. The friction coefficient is further enhanced by providing grooves on surfaces of the friction material and by other means. A friction coefficient 50% higher than those of conventional metallic friction materials has been accomplished. Basic performance of ceramic friction materials was studied and a ceramic material was selected. Problems special to safety gears were studied in a miniature test using a safety gear for small elevators. A drop test was conducted using a drop test apparatus equivalent to an actual cage.