I would guess around the early 1940's
I believe that it was early 40's that Trimont was a division of Aetna Industrial Corporation
and one of their flyers on ebay now shows the ROXCO on the wrench.
I have yet been able to find a complete history on Trimont.
in Kenneth Cope's wrench book, it states that Trimont bought the Diamond wrench co, Portland, Maine
in the 1890's. Diamond was put up for sale around 1893, so that may be when Trimont bought them.
Trimont also bought Moore drop forge of Springfield, Mass. in 1929, they also made pipe wrenches.
it had to be the late 30's or early 40's that they became a division of Aetna Ind. Corp.