Politecnico di Torino - Corso Duca degli Abruzzi, 24 - 10129 Torino, ITALY

+39 011 090 6100 info@tech-share.it


Actuation MechanismElbow jointJoint prosthesisMotion assist device


State of the art known devices support the elbow joint for both the bending and extension movements. Although these exoskeletons have the ability to assist the wearer’s two arms, using an implementation system through the under-implementation strategy, the mechanism does not include an elastic element. Due to this missing component, the transmission of force from the assistive device to the human body cannot be performed in a compliant manner. Thus, the smoothness of the movement of the wearer can be carried out negatively. The aim of this invention is to assist the movement of the elbow joint where the actuation mechanism takes into account the characteristic torsion/angle profile of the elbow.

Technical features

Movement assistive device for the elbow joint, comprising: an actuation unit provided with a motor; at least two arm garments removably attachable to an arm of the wearer; at least one transmission cable. The actuation unit of said cable, comprises: at least one elastic element coupled with the motor and configured to generate, under tension, an elastic force, the at least one transmission cable connecting the at least one elastic element to the at least two arm garments to apply the assistive torque to the wearer arm; at least one cam-spool mechanism configured to elongate the at least one elastic element as a function of human elbow torque/angle profile, wherein each cam-spool mechanism comprises: a cam curve with rotatable camshaft to move a respective transmission cable around the cam curve; a roller and a spool provided with a slot, the spool being coupled with the camshaft though a roller that can slide inside the slot; wherein the rotation axis of the camshaft is decoupled and offset from the rotation axis of the spool.

Possible Applications

  • Motion assist device for elbow joint


  • Preservation of the characteristic torque/angle profile of the human elbow
  • Allows free movements during the extension of the joint, thanks to a single motor coupled with an elastic and a coupling mechanism
  • The elbow torque assistance is effectively transmitted with an average success of 90%