Arrow-Hart & Hegeman electric panels

Anyone know when Arrow-Hart & Hegeman went out of business or were bought by another company?

Arrow-Hart & Hegeman was the successor (merged in 1929) of a holding company formed in 1927 that owned two original companies (Arrow Electric and the Hart & Hegeman Mfg. Co.). They got into trouble with the FTC for the way they chose to organize but were eventually exonerated (I think) by the Supreme Court in about 1935.
I skimmed through all that but didn’t find and absolute answer, but I am pretty sure the company eventually became just Arrow-Hart, the remnants of which are a part of Cooper Industried today.