Thorens was originally a Swiss company that made music boxes and later used its clockwork mechanisms on phonographs and gramophones then made the jump to electrify their work. I would not be qualified to comment on any meaning behind the box design and the company seems to have lost interest in its past--they've ignored any direct queries from me, anyway. The design did strike me as reminiscent of a Star of David, but that's all I can say.
I found another Thorens Star of David on a music box in Ebay along with many other Jewish symbols in a painting made by Jewish-American painter Arthur Szyk in 1943.
It seems that Thorens allowed customers to put their own design on their music boxes and the one Keith owns belonged probably to a Jew.