Technical innovation may restore a degree of tranquility to being outdoors this summer

Benedict Bahner
ASME NEWS

It's a sound that most of us are starting to hear about this time of year, and it's not a pleasant one: the high-pitched whine of yard trimmers as their blunt, round fishing lines slash through the air in search of an errant weed to whack.

It's a noise Vince Morabit knows well, having worked in the business of lawn care and construction products for nearly 40 years. Now, armed with two patents, Morabit and his company, Aero-Flex Technologies Inc., are trying to change the way weed trimmers run — and sound.

Morabit has lots of experience with weed trimmers; he designed and manufactured them for many years when he worked at Homelite, a producer of chainsaws, trimmers and construction equipment. He used them at home, so he also knows the noise they create.

"The string trimmer is a very handy product; it's just not a very efficient one," said Morabit, an ASME member, noting that more than 40 million trimmers are in use in the United States. "The biggest problem with current weed trimmers is the functional inadequacy of the line and the systems that feed the line."

The line used in most trimmers since their invention in the early 1970s — round nylon fishing line — breaks easily. And after the line breaks, it frequently jams the trimmer because it's often drawn back into the trimmer head. Even if the head doesn't jam, the user has the problem of advancing the line to replace the string that broke off. That entails either smacking the trimmer on a hard surface to feed line to the trimmer head or taking apart the machine's head manually and unspooling the filament.

And then there's the noise.

"String trimmers that use the round monofilament fishing line give off a high-pitched hiss," Morabit said. "Add this to the lower-pitched bark from the motor, and you've got a pretty noisy machine." These trimmers also require their engines to run at high speeds to enable the round line to cut, creating even more noise, he said.

Four years ago, Morabit undertook a market research program with his former employer, Homelite, now a division of John Deere Consumer Products. The study, Morabit said, revealed that more than 90 percent of those surveyed would be willing to pay a premium for a trimmer solution like that offered by Aero-Flex.

Since then, Morabit and his two sons, Christopher and Michael Morabito, spent more than $400,000 trying to remedy the problems posed by weed whackers. Last year, they received two patents — for aerodynamic cutting string and for a string trimmer operation system.

In December, their company, Aero-Flex, began production of trimmer heads that employ their new cutting string system, and is currently selling the device at a farmer's outlet in Rock Hill, S.C. Morabit is also in talks with large manufacturers such as John Deere to license the trimmer technology for use on their trimmers. He is also distributing the trimmer conversion heads through a Web site and a network of hardware, garden and home center stores.

These Aero-Flex trimmer heads, which attach to existing weed trimmers, incorporate a number of elements that eliminate or greatly reduce the air drag, fluttering and force imbalances that cause excessive noise.

The teardrop shape of the Aero-Flex line lowers air resistance, enabling the nylon blade to cut at much lower speeds, thereby rendering it operational up to 50 times longer than a traditional round string. Fuel usage is reduced, too, because power isn't being wasted getting the motor up to the higher speeds necessary to enable the round fishing line to cut weeds and grass. By changing to a set of paddle-like nylon blades, the trimming system becomes a low-noise leaf sweeper.

With tens of millions of weed trimmers and power blowers in use throughout the United States, the noise created by these machines has become a public issue, Morabit said.

"There is an environmental concern," he said. "For example, California has passed laws banning or severely curtailing power blowers because of the noise. People in many communities are being disturbed. It's my hope that this technology will help the industry to decrease noise and create a more pleasant and friendly machine."

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