Knuckle joint (Maximum bending stress)


A knuckle joint is a mechanical joint used to connect two rods which are under a tensile load, when there is a requirement of small amount of flexibility, or angular moment is necessary. There is always axial or linear line of action of load. Assume there is no clearance or slack but in actual, knuckle pin is loose in forks to permit angular moment of one with respect to other, so it is subjected to bending moment in addition to shear, consider uniformly distributed load along the portion of pin. Checking the pin in bending and find the value of the diameter maximum bending stress can be calculated by this diameter, the thickness of fork and the thickness of single eye.

Related formulas


σbMaximum bending stress (Pa)
F_τAxial tensile force on rod (N)
t1Thickness of fork (m)
tThickness of single eye (m)
dpDiameter of knuckle pin (m)