Get Pumped Pirouette the lawn mower. Ring in a home run. Lower the roof. Anything hydraulics can't do? By Jonathan Blum February 01, 2005 Uncategorized SHARE Slideshow: Yakima E-Z Load The Yakima E-Z Load delivers equipment from a vehicle’s roof to its side with minimal effort. The articulating arms that swing the apparatus down are controlled by two matching gas shocks that are hardier versions of those found in a car’s trunk lid. On the descent, the shocks–filled with nitrogen and sealed by a jacket of hydraulic fluid that changes shape as the piston moves but never changes volume–compress to check the rack’s movement. Push the rack back up, and the shocks kick in with 20 pounds each of assist. $400 Phillie’s Liberty Bell A new fixture at the Philadelphia Phillies’ stadium, this 6,250-pound neon Liberty Bell relies on hydraulics to swing after home runs. The tricky part was keeping the bell from wobbling at the end of its 7.5-degree arc. When not loaded, the fluids collected at the low points in the lines and stayed there until pressurized; when reloaded, they sloshed around, shaking the piston and, in turn, the bell. Since the last thing Philly needed was two broken Liberty Bells, engineers programmed the hydraulic cylinder to stop midcycle so that the pistons remain under constant load. Bleacher seat: $22 Lawn-Boy’s ZRT mower Lawn-Boy’s zero-radius-turning (ZRT) mower uses independently rotating rear-drive wheels to spin around a single point. The engine runs hydraulic motors at each rear axle, and the steering handles manage how much fluid goes to each motor. Pushing the handle increases flow and, proportionally, speed. $3,800 hydraulics lawn mowers MORE TO READ RELATED Dam reservoirs may be much bigger sources of carbon emissions than we thought We thought dams were good for the environment, but they may actually release immense amounts of carbon. READ NOW RELATED Kids age 12 to 15 can now get vaccinated in the US Ahead of the upcoming school year, a new... RELATED Ask Us Anything: Why can’t we see more colors? Other animals see many more than we do.