For common people, it is nearly impossible to distinguish universal joints, even when you select universal joint from shaft couplings. Universal joints come in a lot of shapes and sizes that enable them to accommodate an infinite amount of applications. Universal joints are used in aircraft, appliances, instrumentation, medical, control mechanisms, electronics and optical devices along with sewing machines, ordnance, textile machinery and tool drives.
Universal joint is a mechanism for variable angle power transmission, which is used to change the direction of the transmission system, as the "joint" part of the car drive system. Universal joints will withstand various forces, such as torsion and centrifugal force, during high-speed motion. Universal joint is located in the active area and is subject to harsh working conditions, which is easy to wear and fragile.