These spider / jaw mechanical power transmission couplings are torsionally flexible shaft couplings, the operating characteristics of which are two hubs with concave claws, transmitting the torque by meshing with an elastic involute gear ring. The spider coupling concept gives a reliable, smooth power transmission without torsional oscillation / vibration and so protects the connected machinery.

Due to the complete flexibility and ductility of the elastomer ring, it compensates for parallel and angular displacements as well as to absorb longitudinal movement of the shafts. The involute teeth of the elastomeric inserts are crowned in order to avoid edge pressure on the tooth flanks and so avoid undesirable axial thrust. The puncture proof spider coupling can be loaded extremely high since the elastic elements are submitted to compression and not to bending moments of force. The elastomer gear ring, made of a newly developed polyurethane of various degrees of shore hardness, has important advantages in comparison with the standard polyurethanes.