Shoot to Shatter

Quiet Jackhammer Fires Nails, Cracks Concrete

Gaby Ciccarelli and Mano Subudhi usually have their eyes on big science, like experimental nuclear reactors. But on a recent spring day, the two engineers from Brookhaven National Laboratory spread before them the diagrams for a quieter jackhammer, a humble project that won an award last month for technological innovation from Discover magazine.

Having toiled on the jackhammer for about four years, the pair makes the idea sound simple. Regular jackhammers work by pounding the pavement, chiseling with brute force. Subudhi says their jackhammer fires a series of steel nails designed to penetrate cement. "A crack will grow from one nail to the other nail," he says. "So if you put in a line of five nails, then all five impact points will be joined by a crack." Eventually the concrete is so fissured you can scoop it up with a shovel.

The latest design, known as RAPTOR, is bright yellow and powered by helium. Turn on the gas and this baby will shoot projectiles into a target the same way a gun fires bullets. "The way it is now, it's a rifle," says Ciccarelli.

And it's about as thunderous, too. The engineers must now design a safety skirt and a silencer for their jackhammer. Though the Long Island lab hasn't taken a decibel reading yet, estimates of the noise level range from 110 (about the racket of an ordinary jackhammer) to 140—nearly twice as loud as the RAPTOR should eventually be. The pair also plans to shrink the RAPTOR; the first prototype, made by James Powell and Morris Reich, was 15 feet long and weighed 500 pounds—a burden since sliced in half. When the machine hits the street, in about two years, it will likely weigh just 200 pounds.

Now that the lab has proved the RAPTOR can crack concrete, efforts are under way to build a more practical version, backed by private investors. Con Edison, Keyspan Energy, the Southern California Gas Company, and primary backer Gas Research Institute of Chicago have already shelled out a total of $875,000—and the scientists have asked them for another $150,000. "They want it to get to the marketplace as fast as possible," says Ciccarelli. And for good reason: Workers using the quieter jackhammer could drill into the night without violating noise ordinances.

The engineers say they're not sure who came up with the idea of a nail-shooting jackhammer. It was included in a report generated by the National Infrastructure Center for Engineering Systems and Technology, a New York State conference held in the mid '90s, at which scientists and researchers discussed ways to improve municipal machinery.

Subudhi and Ciccarelli hope to finish tinkering with the rig before summer ends. The goal is to fire up to 10 nails per minute, break up concrete twice as fast as a standard-issue jackhammer, and leave workers' hands free. "You can put on a remote control," says Subudhi. "You don't need a human, even."

Subudhi says the time is approaching when industry will take over what has so far been a laboratory exercise. The RAPTOR still needs a magazine loader and a safety feature to prevent it from being picked up and used as a gun. Those tasks will likely fall to whoever markets the machine. "We're researchers, not manufacturers," he says. "The manufacturer has to come on board wanting to build it."

 
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