Standardized Long-Stroke Gripper with Carbon Fiber Housing

22 October 2013

The CGH long-stroke gripper from SCHUNK is a milestone in handling. For the first time SCHUNK, the competence leader for clamping technology and gripping systems has succeeded in standardizing a light-weight gripper with Carbon Fiber Composite (CFC) housings. The versatile module convinces in terms of energy-efficiency and economic efficiency by increasing the dynamics of existing systems or enabling it to be used with smaller robots.

The standardised CGH light-weight gripper is the result of modern simulation methods, intensive testing and economic manufacturing processes. The long-stroke gripper benefits from the specific material characteristics of CFC. Its E-value is four times higher and its tensile force is twice as high as that of aluminum. The gripper weight has been reduced by over 40%.

In order to take complete advantage of the composite fiber technology and to ensure high stability of the gripper, the SCHUNK development engineers have manufactured the gripper housing according to the specific stress requirements by using an RTM process. The result is a light and rigid gripper that has a correspondingly torsional stiffness. At a weight of 11.7kg, the CGH delivers a gripping force of 2,500N and a variable stroke per gripper finger of up to 160mm.

The decoupled re-circulating ball carriages ensure that the acting moments will be optimally distributed onto the whole rolling elements. This way an enormous efficiency is achieved with up to 90% of the used energy arriving at the finger. Through the number and distance of the guide carriages, the module can be exactly adjusted to the individual load. For particularly high gripping forces or very long fingers, the distance between the carriages is increased. Therefore it is possible to use fingers with a length of more than 1m and the same clamping forces will act along the whole finger length.

To further increase the gripper efficiency, the stroke can be scaled at damped end positions. The positions 'open' and 'closed' are adjusted according to the requirements and the complete cylinder does not have to be pressurised and de-pressurised at every cycle. This minimizes cycle times and also reduces compressed air consumption. The scope-free belt-drive and the synchronized fingers ensure that the gripper is also working precisely in case of varying strokes where small and big components can be alternately handled. Various robots can be directly adapted via an ISO flange.