The ability to leap tall buildings in a single bound used to be the stuff of comic-book fantasy. Nathan Ball, a 23-year-old graduate student at the Massachusetts Institute of Technology and this year’s winner of the $30,000 Lemelson-MIT Student Prize, has invented a device that makes the fantasy a reality.
With the help of Ball’s ATLAS Powered Rope Ascender, a fully loaded firefighter could reach the top of a 30-story building in only 30 seconds, compared to the six minutes or more it often takes to trudge up stairs with 80 to 100 pounds of equipment. The device, which is the size of a hand-held power tool, can lift a 250-pound load more than 600 feet into the air at nearly 10 feet per second, all on a single battery charge.
In November 2004, Ball and three colleagues entered the Soldier Design Competition sponsored by the MIT Institute for Soldier Nanotechnologies. The competition called for a high-powered device to enable rapid vertical mobility.
Ball called the challenge unprecedented, as the original specifications called for a device that weighed less than 25 pounds and could lift 250 pounds 50 feet into the air, in five seconds. “That’s more than five horsepower in a 25-pound package,” he explained. “That’s a power-to-weight ratio higher than a Dodge Viper’s – we did the math. To have that much power in that small of a package is a heck of a challenge.”
Through a combination of resourcefulness and “the highest-tech equipment we could afford,” such as drill batteries and a few high-power density motors, Ball and his colleagues invented a device that could hoist 250 pounds of weight 50 feet into the air in seven seconds—only two seconds slower than the competition’s specification.
The novel aspect of the ATLAS ascender is its rope-handling mechanism. Similar to the way an anchor is raised and lowered on a ship, the device relies on the capstan effect, which produces a tighter grip each consecutive time a rope is wrapped around a cylinder. The grip continues to tighten as more weight is applied to the line.
In his design, a standard-sized rope (between three-eighths and five-eighths of an inch) is weaved between a series of specially configured rollers that sit on top of a turning spindle. As the battery-powered spindle rotates, it continuously pulls rope through the device. “We currently have three patents pending for the rope interaction and other iterations on the device,” said Ball.
Ball and his colleagues founded Atlas Devices to develop and market the ATLAS Powered Rope Ascender. He has upgraded the original design, and the device is now powered by high-density, lithium-ion batteries created by A123Systems. Ball said the new power system immediately dropped the device’s weight by several pounds and significantly increased its speed.
“The latest configuration weighs 20 pounds and peaks at 10 feet per second,” he said. “A123Systems has a 150-foot steam tower we were able to use for testing. We successfully completed a 100-foot continuous ascent to the tower’s platform in 14 seconds.”
Ball envisions his invention having practical applications in rescue work, recreational climbing and cave exploration, as well as urban warfare situations. “It can help people complete tasks more efficiently and without depleting energy they would otherwise use climbing ladders and carrying heavy gear,” he said.