[Jon Stratis]

Picking up tubes is all about positioning - So long as your mechanism can be positioned properly, and works quickly, you'll be fine. That can be done with both claws and rollers. Rollers work actively, and if left on automatically - you drive into a tube and the rollers have instant control of it. A claw, on the other hand, needs to be activated when you want to pick up the tube. This can be done by one of your drivers, or if your clever you might be able to come up with some sort of limit switch to automatically activate it. In the end, you can get a claw to close incredibly quickly, using either a motor or a pneumatic piston. Just think about the brakes on your bicycle... you don't need to squeeze them very far in order to get them to move in and grab the wheel.