Glossary term
Yoke
A forked or frame-like mechanical component used to connect, support, guide, or transmit load between parts.
Definition
deviceA yoke is a forked, U-shaped, or frame-like component that connects, supports, guides, or transmits load between mechanical parts.
Yokes appear in clevis joints, universal joints, actuator linkages, hoisting equipment, steering mechanisms, valve gear, suspension parts, and magnetic or electromechanical assemblies. Their design is governed by load path, pin or bearing contact, bending, shear, fatigue, alignment, clearance, manufacturability, and inspection access.
A yoke is a structural connector shaped to hold or straddle another part. In a clevis joint, the yoke arms carry a pin that connects to a mating lug or rod end. In a universal joint, yokes transmit torque across intersecting shafts. In lifting hardware and actuators, yokes provide a compact way to connect a load path while allowing rotation or articulation.
The simple shape can hide complex stresses. Loads enter through pins, threads, welds, bearings, flanges, or shafts, and then pass through the yoke arms into the body. Local bearing pressure, pin bending, arm spreading, lug tear-out, thread engagement, weld quality, and stress concentration around holes are often more important than gross section area.
Engineering use
Yokes are used in hydraulic cylinders, aircraft control linkages, cranes, hoists, steering systems, suspension links, clutches, drive shafts, valve actuators, and test fixtures. Design checks may include double-shear assumptions, bearing stress, net-section tension, bending of the arms, fatigue at holes, buckling of thin arms, wear, corrosion, and misalignment.
Manufacturing and assembly details matter. Hole position, parallelism of arms, pin clearance, surface finish, lubrication, heat treatment, retaining hardware, and inspection access affect performance. A yoke that is strong in a static calculation can still fail through fretting, fatigue, galling, poor fit, or overload during installation.
Common mistakes
A common mistake is assuming that a pin joint automatically loads both yoke arms equally. Misalignment, clearance, bending, and tolerance stack-up can shift load to one side. Another mistake is checking only axial load while ignoring pin bending, bearing pressure, fatigue, and stress concentration at the fork root. A strong yoke design review states load cases, pin diameter, material, heat treatment, clearances, tolerances, lubrication, fatigue basis, retaining method, and inspection criteria.