What Is an Air Gripper?
An air gripper is a mechanical device used to hold the inner surface of a workpiece. It operates by expanding a hollow, cylindrical piece of rubber into a doughnut shape when air is injected into it, creating friction to hold the item. Similarly, a gripper that holds the outer surface of a workpiece using this principle is also referred to as an air gripper.
With a broad range of applicable inner diameters (e.g., φ16~21), a single air gripper can handle multiple types of workpieces. Materials used include chloroprene rubber, with silicone as an option for high-heat resistance applications or in the food industry.
Uses of Air Grippers
Air grippers are utilized in the transportation of objects like glass bottles, PET bottles, cans, and printer drums, which can only be handled from the inside. They are also employed in air leak testing for automotive components such as fuel tanks and mufflers, as well as in pumps.
These grippers are advantageous in handling and transporting rolled products like saran wrap, thanks to their ability to grip workpieces of varying diameters with a single size. They are widely used in the end-effectors of industrial and cooperative robots, particularly for gripping the insides of objects.
The silicone variant is chemically stable, exhibiting low temperature dependence and excellent resistance to extreme temperatures. It’s commonly used in the transportation of sensitive materials such as food and garments.
Principles of Air Grippers
Air grippers can grip and release workpieces weighing up to 70 times their own weight. This is achieved by rapidly and reliably injecting and exhausting air, without damaging the workpiece’s surface.
The concentric expansion of the rubber component accommodates workpieces of various diameters using a single size. This versatility reduces the time spent on changing chucks.
However, care is necessary as the rubber can crack or leak over time due to wear or exposure to harsh conditions. Regular checks are needed to avoid damage from sharp objects, UV deterioration, or environmental mismatches.
When dealing with workpieces with low friction coefficients, surfaces covered in substances like oil or water, or shapes prone to slipping, a sufficient safety factor is crucial due to the reliance on friction for holding. The clamping force can be adjusted for fragile parts using an air regulator.