Henri Pieper was born in 1840 to Heinrich Pieper & Elisabeth Blesse or Blaise in Soest Westphalia. Today Soest is in Germany. http://en.wikipedia.org/wiki/Soest,_Germany
Henri filed at least 69 patents. Many were filed in multiple countries. They included such diverse subjects as a lamp wick holder, incandescent bulb holder, electric gun, magazine clip, monobloc barrels, and much more.
Henri registered the Bayard trade name and mark on June 9, 1892.
In 1881 he filed the 1st patent for a monobloc, which would become his Diana shotgun.
He filed 3 patents in quick succession that dealt with lock up, they are
Feb 28 1891 - 93831;
Apr 30 1891 - 94490;
Dec 15 1891 - 96980.
The patent numbers are for Belgian patents. I do not know if any of them are for the lock up in question.
In 1892 he released the modified Diana, also a monoblock, which does not have this lock up.