We designed a 4-claw gripper & fabricated it at 1:4 scale using a 3D printer. The test ball is a little large (7" instead of 6") but seems to work okay. http://youtu.be/FoE1ImP0pQI
A center poppet actuates the gripper fingers. We were hoping it could also launch the ball if we extended it rapidly, but full sized pneumatic tests were not encouraging. The cylinder travel was just too short.