Looks to me like it might be Glasscof with an f and not an e.
It’s not a name I can remember here in Britain but it’s worth bearing in mind that back then, there were lots of makers at the lower (often unscrupulous) end of the market who stamped locks and keys with similar claims and markings which in reality meant nothing.
They also had a trick for making keys look like 10, 12 or 14 lever- they would produce locks with several very thick levers in the lever pack. The keys would then be made with additional false cuts where the thicker levers were, creating a more complex looking key which suggested the lock had far more levers than it really had.
Not sure if yours is such a lock but I’m sure if it is a genuine patent and Glasscof a reputable maker then someone on here will recognise it.
