The Grieshaber hump filler had a tab or hump sticking out of the side of the barrel which was pressed to fill the pen. The only difference between this and the Conklin crescent filler is that his locking device was a knob on the end of the barrel that connected to a tube with a spiral cut edge. When the knob was turned, the shorter part of the tube would unlock the filler button. Although this pen was patented in 1910 the earliest advertising I could find for it was 1919. Filigrees were available on the eyedropper fill and the hump filler pens. He trademarked the name "Umpire" and assigned this name to some of his pens. I guess he thought it would go over better than Grieshaber. Screw caps appeared on most of his pens  in 1920.  By 1923 he switched over to lever fill pens and finally seems to have added pocket clips to the line. The line seems to have all black pens with the exception of some overlays.  The plastic pens seem to start in 1927 although he was still selling some hard rubber pens. The plastic [celluloid] models came in the colors burgundy , jade green , Alice blue and deep coral. The hard rubber colors were black, mahogany and venetian red. The big oversize model was named the Executive model. There was also a line of hand painted ladies pens added.  Some of these ladies pens had  great floral patterns. In 1928 the hand painting also came on gold filled pens.
By 1929 the hard rubber pens were finally dropped. The large oversize pens were now named the "Executive " line.  The new line-up of colors was Burgundy , jade green , jet black + pearl, gold + green, robin's egg blue, deep coral and venetian red.  The tops of the caps on most of the line now had 2 gold bands with black inserts.  The clips now were marked only with the stylized "G" instead of the whole Grieshaber name like on previous models.
In 1930 the single cap band was replaced with 2 or 3 caps bands on most models.  The oversize line was now named the "Savoy" pen. The bands at the top of the cap were dropped on the pens that had more than one cap band. Also in 1930 was their first attempt at a streamlined pen. It was basically their flattop pen with the ends rounded off and a slight taper on the end of the barrel. This streamlined pen was called the Moderne and came in only one color, a black veined pearl. 
In 1932 an attempt was made to give the whole line a streamlined look by putting a beveled edge on the end caps of the pens.  This beveled edge may actually been done to old stock pens in an attempt to make them look more like the streamlined pens that the buying public wanted.
Also in 1932 combinations were added to the line.  The Savoy line of streamlined pens became more streamlined and looked less like a flattop pen with the ends rounded off.  Actually, it looks suspiciously like the Conklin Endura Symetrik pens. This resistance to streamlining their pens was probably a major blow to Grieshaber. 
In 1933 there was a new attempt to restyle the pen line. The Savoy streamlined style of pens basically became the whole pen line with a few of the beveled edge models still being offered.  The old style "Z" clips were dropped in favor of the clasp style clips [the clips that are pressed on and the tabs are bent over on the inside of the cap].  These clips were unmarked and even the barrel imprints were soon dropped.  On some of these pens only the nibs were signed.  I believe this was the end of the Grieshaber pen line although I did find some listed as late as 1937.
In 1930 and 1931 Grieshaber sold a line of pens called the "Transparo". These pens were made by Sager.  Sager may have ended up buying out the Grieshaber company.  The Transparo pens were slightly different from the Sager Barrel Of Ink line of fountain pens.
The failure of Grieshaber was in part because of the depression and also because of their reluctance to keep up with the demands of the buying public. They were too slow at adding clips to their pens, too slow to switch over to celluloid from hard rubber and finally they did not want to change over to streamlined pens until they probably just couldn't sell any flattops pens. I think their reluctance to switch to streamlined pens was a large amount of unsold flattops or unassembled flattop parts.  None of this diminished the sheer beauty of the Grieshaber line. Even though the flattops may have been out of style in the 30s, they made some really nice high quality pens. .

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