Oldhlms Coupling

An Oldham’s coupling is a mechanical device used to connect two parallel shafts that have a small lateral misalignment, allowing them to transmit rotary motion smoothly. It consists of two flanges—one fixed to each shaft—each having a slot cut across its face. Between them sits a central floating disc (also called the intermediate or connecting flange) with two tongues on opposite faces, oriented at 90° to each other. Each tongue fits into the slot of its respective flange. When the driving shaft rotates, its flange drives the central disc via one tongue, and the disc in turn drives the driven shaft’s flange via the other tongue. As the shafts rotate, the central disc slides alternately in both slots, accommodating the lateral offset while maintaining torque transmission. This simple three‑piece assembly is compact, easy to assemble/disassemble, and is commonly used in applications like small machinery, pumps, and precision equipment where shafts are parallel but not perfectly collinear.