http://www.team20.com/wp-content/upl...2013-robot.jpg
This photo of our robot is from the last few days of build season. The climber hooks are made two pieces of 1/8" sheet aluminum, waterjet cut into a shape like what Adam suggested, then with stand-offs between them and flat-head bolts holding it all together. This mitigates any bending load on the piston when lifting. We then have C-channel that goes around the hooks. The front edge of the C-channel is what would contact the lowest bar of the pyramid when our driver slammed into it. We did end up adding another diagonal brace to the C-channel at our 2nd regional to add stiffness. This design worked well - we have not bent a lifter piston all year.
I prefer to design robots in a way that the driver doesn't have to think twice about driving hard. If we have to tell our driver "don't drive to the best of your ability in a way that gives us the best chance of winning a match because this could break," then we're doing it wrong.
The draw back of this approach is that our robot cannot go under the pyramid. This ability was already sacrificed by other aspects of our design, so it didn't really matter for us. We prioritized a simple, linear design, holding 4 discs, scoring upside down discs (before the rule update; only satisfactory prototype was a large rotary shooter), and floor pickup over driving under the pyramid. Maybe if we had used a compact linear shooter or used a bucket hopper and come up with the idea of spring-loaded hooks like we saw on other bots, we could have gone under the pyramid.
Looks solid, Andrew. Does that floor pickup have a pinch bar or roller bar above the lexan plate?