Schunk GmbH last week released its EGL-C long-stroke gripper, which it said “represents a milestone in the road to achieving comprehensive human-robot collaboration.” The gripper is designed to achieve high gripping forces while complying with global safety standards.

The company claimed that the EGL-C is the world’s first long-stroke gripper for collaborative operation. It achieves high gripping forces up to 450 N, combined with a long stroke of 42.5 mm per finger.

The intelligent 24V powerhouse is suitable for handling workpiece weights up to 2.25 kg and can be used in a wide variety of applications, said Schunk. And as an additional plus point, the components will be certified by DGUV for human-robot collaboration (HRC) applications in time for the market launch at the end of 2019.

Editor’s note: Schunk will be exhibiting at the Robotics Summit & Expo in Boston on June 5-6, 2019. Register now to attend.

While the gripping force of the DGUV-certified Schunk grippers to date has been limited to 140 N per finger, the company is now rising to a new league of components with the Co-act EGL-C. For the first time, it said, HRC will be opened up with the potential for handling weights beyond small parts assembly.

The gripping and clamping technology leader said it is focusing its attention primarily on the automotive-related supplier industry, as well as the automotive manufacturers themselves, since they are working intensively on HRC scenarios.

In addition, the specialists from the Schunk Co-act team will also focus on other industrial applications, such as mechanical engineering. The powerful gripper could become an effective accelerator for HRC applications that were previously impossible due to the absence of reliable actuators in the load range up to 2.25 kg.

Combining measurements for safety

In order to comply with the biomechanical exact limit defined in ISO/TS 15066 despite its high gripping force, the Schunk Co-act EGL-C gripper is equipped with combined force and displacement measurement. The force-measuring jaws and incremental encoders integrated in the base jaws permanently monitor the respective gripping force as well as the position of the gripper fingers.

The gripping procedure stored on the gripper, in turn, is divided into several phases, explained Schunk. Up to a theoretical distance of 4 mm to the taught workpiece, which is much less than the thickness of a finger, the gripping force is limited to 30 N.

If a collision occurs during this approach phase, for example, coming in contact with the hand of the operator, the gripper immediately assumes a secure hold with no risk of injury.

It is only in the second phase, such as with a workpiece distance of less than 4 mm, that the fingers close with the user-definable maximum force of up to 450 N. If the system measures flexibility in this closing phase, for example, because a workpiece is being gripped that is too small and the operator wants to remove it by hand, then this motion will also stop automatically. The same applies if the workpiece dimensions expected are exceeded by 2 mm due to reasons such as the absence of a part.

In the third phase, the robotic gripper then detects whether the part has been safely gripped and then activates the integrated maintenance of gripping force by clamping the brake. That means that the gripped part can never be dropped, even in the event of an emergency shutdown. In addition, no referencing is required in the event of a power failure.

Plug & Work for Co-act EGL-C

The powerful long-stroke gripper from the Schunk Co-act series is delivered completely preassembled and is available with the corresponding interfaces for HRC robots, including those from FANUC, KUKA, Nachi, Universal Robots, and Yaskawa, enabling fast and simple commissioning via Plug & Work. A commissioning wizard simplifies the programming process.

In addition, a diagnosis interface allows access to the most important process and status data of the gripper during operation. To make collaboration with the user smooth and intuitive, the gripper is equipped with LED traffic light colored lighting which can be used to signal the appropriate status of the module.

The intelligent Schunk Co-act EGL-C can be optionally controlled and operated via PROFINET, EtherCAT, EtherNet/IP, Modbus/TCP or TCP/IP. As a space-saving solution, the complete control and regulation electronics are installed inside the housing, making decentralized use possible. Due to its 24 V DC operating voltage, the gripper can also be used in mobile applications.

Stable guides and a brushless servo motor ensure a high level of robustness and long-lasting and reliable operation with minimal maintenance costs. The gripper will be available from the end of 2019.