we have a wedge with 2 claws that completely capture 2 bars with pressure, it is designed in such a way even with a pnumatic failure once closed they cannot be opened and only 1 claw on a goal is enough because of the wedge. With switches the capture is automatic or manual with a joystick. With this design it is almost impossible to move a goal we have. We have another non relese one.
Here is a pic:
