Universal Joint Couplings

A universal joint coupling (also called a U-joint or Cardan joint) is a connector that allows two spinning shafts to transmit power even when they are at an angle to each other.
Here is the simple breakdown of what it does:
• Bends Like a Hinge: It has a unique cross-shaped center piece (called a "spider") that pivots inside hinged "yokes" on each shaft. This design acts like a flexible knuckle, letting the connection bend while still turning.
• Works at Angles: It is perfect for situations where one shaft moves up and down or changes angle relative to the other, such as in a car's drive shaft connecting the transmission to the rear axle as the wheels go over bumps.
• Strong, but Needs Grease: U-joints are very strong and can handle significant power and large angles, but they contain moving parts that need regular lubrication to prevent wear.
• Variable Speed (A Catch): A single universal joint makes the output shaft speed up and slow down slightly twice per rotation if it's operating at an angle. In many applications (like car drive shafts), two U-joints are used back-to-back to cancel out this speed variation and ensure smooth power delivery.
In short, a universal joint is a robust, pivoting connector that allows power to turn a corner, making it an essential part of many vehicles and industrial machines.