The company was founded in 1917, and in the 1960's they did get involved in the OEM manufacture of Chordophones. 

They are probably most famous for producing, (and there is some debate about how the name came about), the Tombo Electric Ukulet. This came with a special case that doubled up as an amplifier and could be run from battery or mains, (I would think its quite heavy if it had all of the batteries in?), plus they made a 6 string version, but it was still a 17½in Tenor scale so would be a Guitalele not a Guitar. 

As well as Tombo they also produced Norma branded instruments between 1965 to 1970 which were distributed in the U.S. by Strum´N Drum, Inc. of Chicago, Illinois, (well the electric Guitars certainly were, I'm less sure about them building the Ukuleles but the ones I have seen do have Tombo tuners and do look different enough from other Japanese Ukuleles of the time for it to be likely). 

Other OEM Brands that are attributed to Tombo include Angelica, Asama, Columbus, Condor, Duke, Horugel, Kinor, Montaya, Queen, Regina, Schaffer and Yamato. This may not be all the brands they made, I haven't seen all of these names on Ukuleles and they may not have been the only firm producing them? 

They are still in business today but they only appear to make Harmonicas now.