Collaborative Grippers? Payload Is Not an Issue Anymore

Introduced at the last Hannover Messe and available at the end of this year, the brand-new long-stroke gripper achieves high gripping forces up to 450 N, combines them with a long stroke of 42.5 mm per finger and is suitable for handling workpiece weights of up to 2.25 kg. We asked Andrea Lolli, Area Sales Manager at SCHUNK, to tell us about the features and possible applications of the new product.

by Cesare Pizzorno

Manca davvero poco all’approdo sul mercato della prima pinza collaborativa a corsa lunga e forze di presa fino a 450 N. Il modello Co-act EGL-C di SCHUNK – visto in anteprima all’edizione di quest’anno della Hannover Messe – promette di incidere parecchio sullo sviluppo e la diffusione delle applicazioni collaborative e aumenta le potenzialità di una gamma, quella delle cosiddette pinze collaborative, che il produttore tedesco aveva inaugurato con l’avvento della serie Co-act.
“La nuova pinza Co-act EGL-C – con la ‘C’ che sta per ‘Certified’ – è l’unico prodotto sul mercato in grado di superare il vincolo principale delle applicazioni collaborative, ovvero quello del payload”, racconta l’ingegner Andrea Lolli, Sales Area Manager di SCHUNK. “Sul mercato, infatti, ci sono robot collaborativi da 10 kg e più di payload ma mancava un gripper compatibile, che riuscisse cioè ad andare oltre i limiti imposti dalla normativa vigente in termini di forza, senza intaccare la sicurezza. La EGL-C deriva da un prodotto industriale che già abbiamo a catalogo, vale a dire la pinza elettrica EGL, il nostro gripper elettrico più venduto per componenti pesanti. L’abbiamo rivestita con una cover Co-act che ne elimina gli spigoli vivi e abbiamo portato all’interno della pinza un’elettronica intelligente e ‘safe’. I componenti sono attualmente in fase di certificazione presso l’ente DGUV; la commercializzazione del prodotto è prevista per la fine di quest’anno”.

The first long-stroke collaborative gripper with gripping forces of up to 450 N is just around the corner from the market. SCHUNK’s Co-act EGL-C gripper – previewed at this year’s Hannover Messe – promises to have a major impact on the development and spread of collaborative applications and increases the potential of a range, the so-called collaborative grippers, that the German manufacturer inaugurated with the advent of the Co-act Series. “The new Co-act EGL-C gripper – with the ‘C’ standing for ‘Certified’ – is the only product on the market capable of overcoming the main constraint of collaborative applications, namely that of payload”, says Andrea Lolli, Sales Area Manager at SCHUNK. “On the market, in fact, there are collaborative robots with payload of 10 kg and more but there was a lack of a compatible gripper, namely one that could go beyond the limits imposed by current legislation in terms of strength, without affecting safety.
The EGL-C is based on an industrial product that we already have in our catalogue, namely the EGL electric gripper, our best-selling electric gripper for heavy components. We have coated it with a Co-act cover that eliminates sharp edges and we have brought intelligent and safe electronics inside the gripper. The components are currently being certified by the DGUV. The product is expected to be on the market by the end of this year”.

Combined force and path measurement
To meet the biomechanical limit values that are defined in the ISO/TS 15066 standard despite the high gripping force, the SCHUNK Co-act EGL-C gripper is equipped with a combined force-/ path measurement. Force measuring jaws and an incremental encoder are integrated in the base jaws, and permanently control the individual gripping forces and the position of the gripper fingers.
The gripping procedure is stored in the gripper, and is divided into several phases: Up to a theoretically taught distance of 4 mm to the workpiece – corresponding to far less than the thickness of a finger – the gripping force is limited to 30 N. If a collision should happen in this approach phase, e. g. due to the operator’s hand, the gripper immediately goes to the safety-monitored stop, without the risk of causing an injury. In the second phase, at a workpiece distance lower than 4 mm, the fingers are closing at a freely definable maximum force of up to 450 N. If the system measures a compliance issue in the closing phase – this could happen if a gripped workpiece is too small and the operator wants to remove it manually – this movement is also automatically stopped. The same applies if the expected workpiece dimensions are exceeded by 2 mm, as e.g. no component is available.
In the third and final phase the gripper detects if the component is safely gripped and activates the integrated gripping force maintenance by applying the brake. This ensures that the gripped component does not get lost even in the event of an emergency stop.

‘Plug & Work’ with nearly any type of cobot
The powerful long-stroke gripper from the SCHUNK Co-act Series comes completely preassembled and is available with matching interfaces for HRC robots from several manufacturers.
“The aim – adds Mr Lolli – is to make the gripper work in the simplest possible way, therefore ‘plug & work’, with the several cobots on the market using the most widespread protocols, PROFINET, EtherCAT, EtherNet/IP, Modbus/TCP or TCP/IP. The new collaborative gripper is officially suitable for workpiece weight up to 2.25 kg, although it is important to underline that such a payload is calculated assuming that the grip is made by friction and with a very low coefficient of friction, typically steel on steel. Finally, specific gripping fingers have been developed for this type of gripper, with a rounded shape and consistent with the whole design. Of course, it is still possible for customers to build their own gripping fingers, in compliance with both their requirements and the features of the workpiece to be handled”. With the launch of the Co-act EGL-C gripper, SCHUNK puts a strong focus on the automotive-related supply industry, and also on carmakers, who are intensively working on relevant HRC scenarios. Some more industries are therefore interested, such as machine building, where the powerful grippers may be able to achieve rapid success in HRC applications.