Velcro fasteners, the lotus effect, and airplane wings are prominent examples of how bionics can solve technical problems. The vacuum specialists at Schmalz found a powerful model in nature. Harald Kuolt, head of research at the handling experts at Schmalz, discovered the leech.
These creatures, which aren't particularly appetizing, possess the ability to cling to various surfaces with their two sucking organs at the front and rear ends. Whether slimy or porous, underwater or above water – thanks to the combination of suction and mechanical grasping or clamping, they can securely attach themselves to their hosts. Schmalz launched a project with the University of Freiburg to better understand these biological adhesion systems. "We investigated the functional morphology and biomechanics of leeches"explains Professor Thomas Speck, head of the "Botany – Functional Morphology and Bionics" at the University of Freiburg.
Th. Speck
The researchers used rotating systems to determine the centrifugal force at which leeches detach from their respective surfaces. "We were breaking new ground and developed special experimental setups to measure the adhesive forces of the leeches"explains Thomas Speck. In a current research project, the team is investigating the anatomy of the sucking organ, which consists of muscle-controlled sucking, sealing, and grasping lips. "Understanding the form-structure-function relationship of the sucking organ is essential for further abstraction and implementation steps for new, bionically optimized systems of leeches"explains Simon Poppinga, who heads basic biological research on the model organism at TU Darmstadt.
Bionically optimize systems
Harald Kuolt: “Our pre-development team then produced a prototype that differs from our standard product range.” For one thing, the sealing lip runs in a different direction than on conventional suction cups. Secondly, Schmalz adjusted the radii of curvature and combined hard and soft materials. “We were able to reduce the dead volume and thus evacuate significantly faster”the research manager is pleased to report. “Our goal is for the new suction cup to perform better than conventional models in terms of holding and shear forces as well as sealing behavior. It should also be suitable for industrial production.” And its carbon footprint must also be comparable to that of existing suction cups.
Photos: Schmalz
The new models save energy thanks to their short evacuation times. They seal better on rough surfaces and offer impressive service life. Thanks to the new seal structure, they are designed to ensure a secure hold even on uneven or sensitive surfaces. "The suction cups must function reliably in standard applications; we don't want to develop a solution for just a few special cases"says Kuolt.
