Variable speed pulley
Variable speed pulley

Variable speed pulley: the most suitable to convey the motion

The pulley is a transmission motion organ and consists of a disk capable of turning around its axis. Some models also include one or more grooves to accommodate one or more ropes, cables and similar races. Depending on the model can rotate on its axis for driving or return, or it can be keyed to a crankshaft to give movement. The pulleys are used in a wide variety of applications, including: - machines - motors - speed changes - elevators - cable transport - cable cars and funiculars.

In the case of this later application, small pulleys are mounted on special supports along the way and serve to give direction to cars, as well as support the weight of the rope and the cars themselves. Larger pulleys are mounted in the stations upstream and downstream, and are directly connected to the engine: this stamp the movement to the whole system and allow the movement of the rope. A particular type of pulley, very adaptable, is the variable speed pulley, which has the characteristic of being able to vary the speed of motion distributed depending if the belt runs on the outside or on the inside of the pulley itself.

This consists of two opposing tapered discs, a fixed and a mobile, and a spring that compresses mobile drive towards that fixed. The operation is very simple: suppose we apply a variable pulley motor and a normal to a fan, the belt is tensioned more and more slowly will turn the fan (because the belt will spin at the smaller diameter), and vice versa. There are also variable pulleys have a knob to adjust the speed. Another category of very useful pulley are the disk expandable pulleys: are useful to change rapidly, and on an ongoing basis, the rotational speed of the rotating shaft without having to stop the machine on which they are mounted.

These are divisible into two large families: - double pulley for variable interest expansion (the change in speed is achieved by changing the distance between the axis of the crankshaft and led) - mono disc changers for fixed interest expandable (allow the transmission of motion with high variance reports, without changing the interest of transmission).