With new design, Under Armour aims to solve age-old issue of keeping pitcher's arm warm

For years, starting big-league pitchers have struggled with a vexing problem -- how to keep their arms warm during down periods without sweating under bulky jackets.

Under Armour, which is trying to broaden its imprint on Major League Baseball, is weighing in with a plan – a single-sleeved jacket.

The sports apparel and footwear company received a patent on March 29 for its "athletic arm warmer with compression sleeve."

It's targeted at starting pitchers sitting in the dugout -- and often sweltering in the summer heat -- when their team is batting.

"In this situation, the pitcher often puts on a full-size quilted winter jacket in an attempt to keep his throwing arm and shoulder warm," Under Armour said in an explanation filed with the U.S. Patent and Trademark Office.

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"However, because baseball is primarily played in the summer, it is often very hot and most pitchers will only place one arm in the jacket. The remainder of the jacket falls to the ground where it is subject to damage from cleats, dirt, and other ground level dugout assaults. If the pitcher does prevent the jacket from falling to the ground in some way, the remainder of the jacket will tend to cover his body and cause him to sweat. Sweat has an adverse effect on gripping a baseball, and is undesirable for the pitcher."

Drawings filed with the patent application depict a one-armed jacket.

"The garment is void of an opposing sleeve configured to receive a second arm," the company said.

Under Armour confirmed Tuesday that the patent was filed and approved. There was no immediate word on plans the company may have to develop the jacket.

Under Armour is very active filing for patents and trademarks.

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The trademarks include Gameday Armour, Baby Armour, Offshore Armour, ArmourBlock, ArmourStretch and ArmourStorm.

In the past two years, Under Armour has been granted 41 U.S. patents, according to data compiled by Bloomberg. The patents cover everything from zippers to water bottles, the news service said.

jebarker@baltsun.com