Team 379 built this prototype gripper using some initial ideas shared by Team 48, including the use of soldered copper tubing, which 48 used for its grippers in 2001. Both teams may choose to employ a variant of this design on their final robots.
When ya can’t fit big honking grippers in the starting box, ya fold 'em up. The folded flaps will spring out with bungee cord, latex tubing, or some other easy tensioning device when the grippers are first opened. Even without the tension (which isn’t present in this picture), the gripper deployed quite well when the cylinder was energized.
2" bore cylinder, 8" stroke - We can use a shorter stroke, and we are investigating 1.5" bore. The current configuration with latex tubing wrap around the copper grips the trackball extremely well.