RINGFEDER RFN7012 Locking Assembly

RFN7012 is a slim, four‑piece locking assembly from RINGFEDER designed to couple a shaft and hub in tight spaces, with a 110 x 155 size variant commonly referenced for this model. It uses double‑tapered thrust rings with self‑releasing tapers to bridge relatively large fit clearances and is easy to install or remove, though it is not self‑centering and typically requires a pre‑centering hub section. The design supports high torque and axial loads, and multiple RFN7012 units can be placed behind one another so their transmission values add, with guidance to position them within 4L to maintain performance. A key advantage is its wear‑free operation—there are no moving parts on the shaft or hub, and tightening creates a surface seal that helps limit contamination during assembly. Common applications include chain wheels, levers, pulleys, slip‑on gear mechanisms, belt drums, running wheels, and cable sheaves; the front thrust rings offer auxiliary threads for removal, and the screws are 12.9‑grade. Surface finishes call for Ra ≈ 3.2 μm on shaft and hub bores, with recommended tolerances of shaft k9–h9 and hub N9–H9 (up to k11–h11 / N11–H11 for maximum admissible loads).