Suburbanites hoping to sleep in on the weekend would like to thank a group of engineering students from Johns Hopkins University. Four students designed a new silencer for a leaf blower that calms the otherwise noisy machine.
The four designed the product as part of their senior capstone at the university’s Whiting School of Engineering, under the sponsorship of Stanley Black and Decker, the world’s largest tool company with $15.8 billion in annual sales. Stanley was so impressed with their invention that he decided to sell it to the public, and the silencer is expected to hit shelves within the next two years at a price that has yet to be determined, according to the company.
The product itself is what the group calls a “spiral cap” that swirls air around the leaf blower nozzle to reduce noise. The cap’s specific geometric design, the students explained, deflects the sound waves that exit the fan’s long nozzle—the same way a car exhaust or a gun silencer works. The trick was to reduce the fan’s noise while still blowing enough air to actually clean a leaf-strewn lawn, said Michael Chacon, one of the students on the project. (Chacon plans to work for a small aerospace company when he graduates.)
Leaf blowers have long had a reputation as a disruptive part of suburban life, their distinct monotonous roar a staple of autumn leaf-picking in the US. Besides being an irritating, if convenient, alternative to hand-raking leaves, leaf blowers also represent a $1.5 billion global industry by 2022, according to market research firm Research and Markets.
As they explored quieter leaf clearing, the group impressed both their professors and Stanley Black and Decker.
“It was a particularly tight-knit, tight-knit, focused group,” said the students’ academic advisor and Johns Hopkins engineering professor Stephen Belkoff. “They hit the ground running. They’re a fun bunch.
Stanley Black and Decker manager Nate Green advised the students. Green himself is a graduate of Johns Hopkins and a former student of Belkoff. That made it “particularly rewarding,” Belkoff says, adding that Green was “somewhat of a leader” of the students.
The cap looks pretty nondescript, a plastic cylindrical attachment that screws onto the end of the fan, but the results are noticeable, reducing the contraption’s overall noise by 37%. “The invention dramatically improves the quality of noise, specifically targeting the frequencies to which the human ear is most sensitive,” said Green. The group went through about 40 versions of the spiral cap before landing on the final one, according to Chacon.
Stanley Black and Decker was so eager to get the leaf blower silencer into stores that it sent patent attorneys to secure a patent application on behalf of the four students. Patent pending. Madison Morrison, one of the group’s members, who says she will do her PhD when she graduates later this month, called the patent a “huge achievement” that gave her a new perspective on engineering.
“That process was really cool because it was a little different side of the engineering field,” Morrison said. “How do you prove your invention? How do you fully cover it from a legal perspective?’
As part of Stanley Black and Decker’s agreement with Johns Hopkins, the company retains all intellectual property and subsequent royalties from their design, but the students’ name will appear on the patent.
For their part, the students said they enjoy the process of going from an idea to a product the business can sell. “It was a great example of how you can take something super theoretical that might just be some research idea and then actually put it into practice,” Morrison said.
Toward the end of the project, Green asked the group to redesign their product so that it could be manufactured using an injection mold that was more suitable for mass production, rather than 3D printing, which they had used for their prototypes, according to Andrew Palacio, a member of the group. Then they realized that Stanley Black and Decker saw real potential in their design.
“Our sponsor [Greene] we sat down with us one day a few months ago and we were given a very strict order to find a way to mass produce the cap,” says Palacio. “At least then I realized, ‘oh, this is probably going to end up on the shelf one day.'”
But there is one thing the group is still unsure about – their grades. Asked if they got an A, all four laughed: “We don’t know yet.”
