Richard Best Pencil Company, Inc. was a family-run business founded in New York City in 1890 and moved to Irvington, NJ in 1907. Curiously, a 1909 U.S. Congressional record detailing a Senate hearing on the topic of taxing pencil lead refers to the company as “Richard Best Pencil Works.” The company's founder and president, Richard Best, submitted at least two letters to the Ways and Means committee where he argued against increasing tariffs on imported lead because it would ultimately hurt the American pencil manufacturing industry (even though the company did not import its lead). Mr. Best died in 1934.
In 1941 the company was granted a trademark for the name "TRYREX," however I do not know when the triangular shape itself was patented. Advertisements for the company in the early 1950s show its headquarters as being in Springfield, New Jersey. Sometime later, Richard Best Pencil Co., along with its patented and iconic Try-Rex pencil shape, was acquired by Lewisburg, Tennessee-based J.R. Moon Pencil Co.