A gripper is a motion device that mimics the movements of people, in the case of the gripper, it is the fingers. A gripper is a device that holds an object so it can be manipulated. It has the ability to hold and release an object while some action is being performed. The fingers are not part of the gripper, they are specialized custom tooling used to grip the object and are referred to as "jaws." Two main types of action are performed by grippers: External: This is the most popular method of holding objects, it is the most simplistic and it requires the shortest stroke length. When the Pneumatic Centering Gripper jaws close, the closing force of the gripper holds that object. Internal: In some applications, the object geometry or the need to access the exterior of the object will require that the object is held from the center. In this case, the opening force of the gripper will be holding the object.
How does a gripper work?
The most widely used gripper is the pneumatically powered gripper; it is basically a cylinder that operates on compressed air. When the air is supplied, the gripper's jaws will close on an object and firmly hold the object while some operation is performed, and when the air direction is changed, the gripper will release the object. Typical uses are to change orientation or to move an object as in a pick-n-place operation.
Major Factors in Choosing a Pneumatic Gripper and Jaw Design:
When choosing a pneumatic gripper and jaw design, these ate the major factors to consider: 1. Part shape, orientation, and dimensional variation If the object has two opposing flat surfaces, then 2 Jaw Parallel Gripper is desired since it can handle some dimensional variation. Jaws can also be designed to handle cylindrical objects with the 2 jaw concept. Keep in mind that retention or encompassing grip requires much less force. 2. Part Weight Grip force must be adequate to secure the object while a desired operation is performed on the object. The type of jaw design must be part of the force requirement. Keep in mind that you should add a safety factor to the amount of force that you select and air pressure is a factor to keep in mind. 3. Accessibility This applies both to the work being performed on the object and the amount of room for the gripper jaws. If the work is to the exterior of the object then it may require an internal grip. Angular grippers are usually less expensive but require additional space for jaw movement. 4. Environmental Harsh environments or cleanroom applications require grippers designed for those purposes. 5. Retention of the Object When air pressure is lost, the gripper will relax its grip on the object and the object may be dropped. There are spring assist grippers designed for this type of application.
Choose the right gripper for your automated process
Pneumatic Parallel Gripper
A parallel gripper opens and closes parallel to the object that it will be holding. These are the most widely used grippers. They are the simplest tool and can compensate for some dimensional variation.
Pneumatic Angular Gripper
An Angular gripper moves the jaws in a radial manner to rotate the jaws away from the object. This allows for the jaws to move completely away from the object. The object may also be fed directly into the jaws and possibly eliminate one additional motion.