The belt transmission device is simple, inexpensive, and does not require axially aligned shafts. They help protect machines from overload and blockage, and dampen and isolate noise and vibration. Load fluctuations are absorbed (buffered) by shocks. They do not require lubrication and minimal maintenance. They have high efficiency (90-98%, usually 95%), high tolerance to misalignment, and relatively low cost if the shafts are far apart. Activate the clutch action by releasing the belt tension. Different speeds can be obtained through stepped or conical pulleys.

Due to sliding and stretching, the angular velocity ratio may not be constant or equal to the angular velocity ratio of the pulley diameter. However, this issue has been largely resolved through the use of toothed belts. The working temperature range is -31 ° F (-35 ° C) to 185 ° F (85 ° C). Adjusting the center distance or adding idlers is crucial for compensating for wear and stretching.

Flat belts were widely used in spool systems in the 19th and early 20th centuries to transmit power in factories. They are also used in countless agricultural, mining, and logging applications, such as trucks, sawmills, threshers, silo blowers, conveyors for filling corn baby beds or pipes, packers, water pumps (for wells, mines, or swamp farmland)

）And the generator. Today, flat belts are still used, although not as much as in the era of online shafts. Flat belt is a simple power transmission system that is very suitable for daily use.

In the case of broadband and large pulleys, it can provide high power at high speeds (500 horsepower, 10000 feet per minute, or 373 kilowatts, 51 meters per second). However, these broadband large pulley drive devices are bulky, occupy a large space, and require high tension, resulting in high loads, and are not suitable for near center applications. Therefore, V-belts are mainly used for short distance flat belt power transmission;

Usually, belts are no longer used for long-distance power transmission. For example, factory machines now tend to have separate electric motors.Due to the tendency of the flat belt to climb towards the higher side of the pulley, the pulley is made with a slightly raised or "coronal" surface (rather than flat) to allow the belt to automatically align during its operation. When a heavy load is applied, the flat belt also tends to slide on the pulley surface, and many proprietary belt dressings can be used to apply to the belt to increase friction and thus increase power transmission.Flat belts are traditionally made of leather or fabric. Today, most are made of rubber or synthetic polymers. If the hair side (outer side) of the leather is assembled with the pulley, the grip of the belt is usually better, although some belts may be half twisted (forming a Mobius belt) before connecting the two ends, so wear can be evenly distributed on both sides of the belt. The end of the belt is connected to leather (the oldest method), steel comb fasteners and/or straps, or by gluing or welding (in the case of polyurethane or polyester).