Belts are used in a wide variety of mechanical processes and we rely on them in our everyday lives: they’re in our cars, our washing machines, at the till at the supermarket, and in the escalators in the local mall. And, of course, they are also used in many industrial processes.
A mechanical belt is a flexible sheet of material linking two or more rotating shafts, and usually sits on top of a pulley. There are a few different kinds of mechanical belt, used mainly for power transmission, but the two main ones are flat belts, which are the oldest type, and the wedge-belt, which is commonly used today, and has replaced the chains and gears in many mechanical processes. The advantage of using a belt is that it is quieter and smoother, and it cushions the motor and bearings, reducing wear and tear.
The main difference between a flat belt and a wedge belt (also known as a v-belt) is that the latter has wedge-shaped (or v-shaped) grooves which sit in mating grooves in the pulley, keeping the belt firmly in place. In fact, the heavier the load, the more the V shape wedges itself into the grooves of the pulley, allowing it to transmit more torque and friction. In addition, while flat belts need to be fairly wide to prevent them from slipping off, wedge belts can be narrower, and the tension can be lower, which means less stress on the belt and bearings. Wedge belts are particularly useful in high powered devices, where it’s important to have both traction and speed. Wedge belts are used in combination with each other in these devices, in what is called a classical wedge belt drive, or a multiple wedge belt drive.
The materials used for making belts have changed over the years. They were once made of leather or fabric, but from the early twentieth century rubber was used, and nowadays most wedge belts are made out of either rubber or synthetic polymers, with cotton, polyester or even steel added to reinforce and strengthen the belts.
The life span of the machine, including the wedge belt, can be increased with preventative maintenance. The belt, and other parts in the system, should be inspected on a regular basis for excessive wear or damage, and the belt tension should be checked.
It’s essential to choose a belt that’s suited to its purpose and context, but a wedge belt is frequently the appropriate choice as it can move at high speeds without slipping off the pulley and tends to have a relatively long life span.