A universal joint, basically consists of a pair of hinges that are located close together, oriented at 90° to each other, and connected by a cross shaft. It is also known as a U joint, or a universal coupling, or a Cardan joint, or a Hardy-Spicer joint, or a Hooke’s joint. It is a joint in a rigid rod, which allows the rod to ‘bend’ in any direction, and it is commonly used in shafts that transmit rotary motion.
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