Ruland PSMR13-5-4-A Flexible Shaft Beam Coupling

Ruland PSMR13-5-4-A is an aluminum, one‑piece flexible beam shaft coupling that joins motors to driven components while accommodating axial and angular misalignment. It features a 12.7 mm (0.50 in) outer diameter, dual bores of 5 mm and 4 mm, and a length of 19.1 mm, designed for compact servo and stepper assemblies. The one‑piece construction eliminates joints and potential failure points, and it is offered with two fixing styles: a set-screw option using one grub screw per shaft (120° apart) or a clamp version using a single socket‑head cap screw per shaft. Typical applications include encoders, stepper motors, robotics, measuring instruments, servo systems, and related automation equipment such as pumps, valves, and fans, where precise torque transmission is required with limited shaft misalignment. Torque and wind‑up are determined by the largest bore selected, making bore choice critical to achieving the desired performance.