Twiflex Limited VKSD Brakes For High Performance Elevator Drives
A major elevator OEM specifies Twiflex VKSD disc brakes for use on high-performance elevator drives installed in skyscrapers. The dual function brakes stop the elevator cars precisely at the correct floor level and also decelerate the cars in an emergency (such as a malfunction). Two caliper modules are used on each elevator drive to provide the required redundant safety.
Unlike electromagnetically actuated brakes found in conventional elevators, the VKSD brakes are hydraulically actuated since each caliper’s clamping force exceeds 100 kN. A dedicated dual-circuit hydraulic unit (also supplied by Twiflex) generates the necessary oil pressure for both brake calipers.
The brake system is designed to dissipate the large amount of kinetic energy (which may exceed 2 kWh) generated by this high rise elevator application. Brake disc temperature can rise by more than 100K during an emergency stop.
The Twiflex VKSD disc brake caliper range is available in a standard configuration comprising two spring modules acting on each side of the disc or, as shown above, as a ‘floating’ brake. The minimum disc thickness is 20 mm, minimum disc diameter is 1000 mm. Rated braking force extends from 28 kN to 119 kN, with a nominal coefficient of friction mu = 0.4.