The Horni Signal Manufacturing Corporation transitioned into wartime industry in a big way in the early 1940s. The following is a January 8, 1943 New York Times article:

BIG OUTPUT GAIN WINS ‘E’; Horni Signal Manufacturing Corp. and 600 Workers Cited
Two years ago the Horni Signal Manufacturing Corporation employed thirty workers in the production of traffic and fire alarm equipment. Today its personnel has expanded to 600, all busily engaged in the war production of secret precision parts for all branches of the armed forces. For increasing its production 1,500 per cent in the last two years, the company received yesterday the Army and Navy “E” for Excellence. The employes, 20 per cent of whom are women, stopped working for a few minutes and gathered in the patriotically decorated machine shop to witness the official award made on behalf of the Army and Navy by Lieut. Col. James T. Mercereau.

Although I do not possess a hard copy, below are the images that I kept from an eBay auction several years back of a war-time publication from Horni.

However, all was not wonderful at Horni Signal as the article above and publication below would lead you to believe.