Gimbal Expansion Joints are designed to allow angular movement in any plane by the use of two pairs of hinges affixed to a common floating gimbal ring. The gimbal ring, hinged and pins are designed to restrain the pressure thrust due to internal pressure and shear forces.
A gimbal ring is either round or square. For round gimbals the torsional moment shall be considered and for square gimbals the instability due to the bending shall be considered.
MWC
Gimbal expansion joint with welding ends.
MFC
Gimbal expansion joint with flanges.