Passive exoskeletons for industry are devices that can effectively facilitate the work performed by the wearer. One of the limitations of existing structures, used in various application fields, is not to correctly respond to normal human physiological movement, given by the non-direct correlation between robotic and human degrees of freedom. This generates discomfort, non-linear movements and often injury. To solve this problem, models based on shoulder rhythm have been presented and developed, focusing on a supporting exoskeleton for heavy operations of the upper limb member. Several geometric models have been proposed that are able to recover the potential energy ofthe movement of the arm with respect to its reference position (non-activated muscular system and arms parallel to the gravity vector).