Although in my time I’ve arranged for the manufacture of lots of them, I wasn’t aware that the protective zip-fastener closure for Bibles was invented by Cambridge University Press. Patent 407848 was registered in 1933. Cambridge had only enjoyed its patent for six years before the zipper was reserved for military use during World War II. The prohibition was lifted in 1947, at which point CUP applied for an extension of their patent protection. Oxford University Press and Collins objected and brought suit. The case was settled in 1950, granting CUP a further seven years’ exclusivity.
As this blog post at Fifteen Eighty Four says “Wrangling between Cambridge, OUP and W. Collins, Sons & Company continued through the 1950s”. This exchange between Geoffrey Cumberlege and Dick David illustrates its tone.
Because you are basically selling the same object, and potentially lots of them, the Bible business has always been rather more cut-throat than academic book publishing.
On Bible manufacturing, see my earlier post.