A Gripper for Handling Large Leather Plies Stacked on Beams

The paper presents the preliminary design of a novel gripper able to grasp large non-rigid materials that has been conceived to face the challenge of automatic handling tasks in the leather industry. The design has been driven by the requirements to limit production costs and the complexity of the grasping device. A statistical analysis of the different templates sizes has allowed to identify a fixed configuration of the gripping points able to properly pick all the sheets within a great confidence interval. According to the varying shape of the leather templates themselves, that is due to their stacking in plies on the beam, the trajectory of the gripping points has been studied and arranged. Due to the irregular shape of the large sheets that are handled, the edges of the non-rigid materials out of the gripping area might flutter during the transferring phase: a four-bar linkage has been specifically designed, so that the motion of its end-effector prevents unwanted leather creases.