String trimmer

It uses a whirling monofilament line instead of a blade, which protrudes from a rotating spindle at the end of a long shaft topped by a gasoline engine or electric motor.

[2] The string trimmer was invented in the early 1970s by George Ballas of Houston, Texas,[3] who conceived the idea while watching the revolving action of the cleaning brushes in an automatic car wash. His first trimmer was made by attaching pieces of heavy duty fishing line to a tin can bolted to an edger.

[citation needed] The terminology used to refer to string trimmers varies by country and sometimes state: A string trimmer works on the principle that a line spun fast enough on its center stiffens by centrifugal force; the faster the hub turns, the more rigid the line.

The motor turns the reel and the line extends horizontally while the operator swings the trimmer about where the plants are to be trimmed.

Newer models "auto-feed", where a small cutter ensures the exposed length does not exceed what can be swung effectively.

Disadvantages of a gasoline-powered string trimmer include its greater weight, the need to refuel, and the significant vibration that carries throughout the device, both of which interfere with its maneuverability and contribute to muscle fatigue.

[citation needed] Many string trimmers allow the hub, the head or the lower part of the shaft to be replaced with accessories.

[citation needed] Battery-powered string trimmers offer cleaner alternatives to consumers by producing zero emissions, being more efficient, and eliminating risks of spilled gasoline.

It is typical for the user to wear either safety glasses or a suitable visor to protect their eyes, but passersby are still at risk.

[citation needed] Chain-link flail rotors, and any other trimmer head with linked metal parts, were prohibited from sale in the EU after a fatal accident in 2010.