According to Wikipedia, the disc brake is “a device for slowing or stopping the rotation of a wheel. A brake disc (or rotor in U.S. English), usually made of cast iron or ceramic, is connected to the wheel or the axle. To stop the wheel, friction material in the form of brake pads (mounted in a device called a brake caliper) is forced mechanically, hydraulically, pneumatically or electromagnetically against both sides of the disc. Friction causes the disc and attached wheel to slow or stop.” This concept is fairly easy to understand as most owners of a motor vehicle such as a car or truck have likely had an opportunity to see a disc brake during the unfortunate event of having to change a flat tire. These discs are fairly small, similar to the diameter of a small 12” (30 cm) pizza.

Now imagine taking this simple braking concept and applying it to something much larger, such as a mine hoist.

This is Twiflex Limited's specialty. Founded in 1946, Twiflex has supplied approximately half a million brakes, frequently for critical applications, to various countries all over the World. Twiflex has one of their “mine winder super brakes” installed in one of South Africa's deepest gold mines at Anglo American's Vaal Reef number 11 shaft. This super brake is installed in what is known as a "Super Winder" designed to raise and lower the weight of 14 family cars down a 3.1 kilometre deep mine shaft. The payload is not excessive, but add the weight of the 3 kilometre long ropes and the engineering requirements make these some of the world's largest winders. Instead of the 12” size disc brake you see on your car or truck, imagine 12 brake calipers acting on two 6.67 metre diameter discs, able to stop a payload of 13,500 kg, to a depth of 3,150 meters, often moving at a speed of 19 m/sec. Very impressive. Imagine the heat created with this much friction. In this special case, Twiflex Development Team needed to work closely with their friction liner manufacturer to develop a material that could maintain its coefficient of friction up to 350 degrees Celsius.

Related Topics: Dynamic Hoist Tests