As design engineer and technical director Alfred Trappen (1828-1908) was the key figure of the “Märkische Maschinenbau-Anstalt” for nearly four decades. This company from Wetter an der Ruhr had evolved from the “Mechanische Werkstatt” of Friedrich Harkort at the same place. Harkort sometimes has been called “Father of the Ruhr Region”.

But lets introduce the “Märkische Maschinenbau-Anstalt” in its own words. In August 1881 they had an advertisement in “Stahl und Eisen” Nr. 2 like so:

Märkische Maschinenbau-Anstalt vormals Kamp & Cie. Wetter a.d. Ruhr, Westfalen baut als Specialität alle für das Hüttenwesen erforderlichen Maschinen und Apparate nach neuesten Erfahrungen, insbesondere zur Anfertigung und Verarbeitung von Stahl und Eisen.

In my translation:

Märkische Machine Building Establishment formerly known as Kamp & Cie. Wetter a.d. Ruhr, Westfalen specialized in engines and apparatuses needed in metallurgy utilizing recent knowledge especially for making and processing steel and iron.

Trappen started in 1845 as a 17 year old apprentice of Maschinenfabrik Kamp & Co. After 6 years training in the shop, at the drafting board as well as in the directors office he started as design engineer in 1851. From 1867 he was responsible as technical director.


The DEMAG (Short for DEutsche Maschinenbau AktienGesellschaft) founded in 1910 was proud to be successor of Friedrich Harkort’s “Mechanische Werkstatt” founded 1819. So DEMAG decided to commemorate 1919 100 years of engineering in Wetter an der Ruhr. They entrusted Conrad Matschoss, a very well known german technology historian, to do a research on the companies history. In 1919 Matschoss published the book “Ein Jahrhundert deutscher Maschinenbau. Von der mechanischen Werkstätte bis zur deutschen Maschinenfabrik, 1819-1919”. Matschoss shows how starting with the “Mechanische Werkstätte Harkort & Co.” at first the company “Kamp & Co.” (Kamp was Harkort’s partner and investor) evolved, later on the “Märkische Maschinenbau-Anstalt” 1.

Matschoss started in 1913 with material which he got from Trappen’s widow as well as from Trappen’s son. There have been hints that Matschoss’ archive has been lost in WW II, when his domicile was destroyed.

In 1999 Rainer Stahlschmidt published another biography of Alfred Trappen 2.

There are only very view publications from Trappen himself. I am aware of some articles in “Stahl und Eisen” (the first one in the first edition in August 1881, the last one in Heft 2 1906). These all deal with engines Trappen wants to present. Furthermore there is one article in the VDI-Zeitung (1885, Band XXIX, S. 237). Stahlschmidt noted that Trappen was hearing impaired and refused for this reason any public appearance.

Plate Shear

Conrad Matschoss had the sketch reproduced in the 1919 commemoration volume, but did not add any comment. The original sketch book is no longer available (Matschoss’ archive was lost when his domicile was burnt in WW II), so there is no context which could help to date the drawing. If I assume the 1850s this is mostly because I found some details about one really big plate shear, built in 1864 für Schulz, Knaudt & Co., a sheet mill founded 1855 in Essen. The engine was a very impressive one, weighing more than 40 t, driven by a steam engine with 400 mm cylinder diameter und 550 mm stroke. Plates up to a width of 900 mm could be sheared 3. Compared with this Trappen’s plate shear is a really simple device.


Alfred Trappen constructed a valve gear variant, which was known under his name. For details refer to 4.

In the very year Trappen’s valve gear was noted in England. Engineering reported at 20.6.1879 about “Trappen’s Valve Gear” 5. They summarized:

The Trappen gear seems to us in every respect one of the simplest and most satisfactory forms which have been given to the type to which it belongs. We do not doubt that in practical working it will prove itself an exceedingly sensitive and efficient speed regulator.

The article was accompanied by a fine drawing - the gear had been patended (D.R.P. 2388 from 6. Januar 1878).

Ironclad-Mill for Krupp in Essen

Obviously Krupp in Essen too relied on Trappen’s knowledge. In 1890 a mill was built by the “Märkische” 6, solely dedicated to produce ironclad. It seems that Trappen was not allowed to publish any details. He sticked to a short description of a reversing engine. According to this the two cylinders had a diameter of 1.300 mm ø with 1.250 mm stroke. With a steam pressure of 5 atm the engine should run a max. 120 rpm. With two spur wheels this was reduced by 1:2,5 so the rollers finally turned with max. 48 rpm. According to Trappen the max. speed was used only for thin plates.

Some 25 years later there were additional references. In 1914 an engineer Schömburg from Essen published an article “Einrichtung und Betrieb von Panzerplatten-Walzwerken” 7 in the Polytechnisches Journal.

There reference values of several rolling mills are given, two of them from Krupp. One of these fits to data given by Trappen and now it becomes clear what astonishing dimensions these mill had been able to handle in 1890:

  • Slabs weighin up to 150 t
  • Nominal Power 4000 PS
  • Rollers with 1200 mm ø, a length of 4000 mm and a stroke of 1200 mm
  • Roller tables 9 m long, steam driven

Obviously the plant was used at least for 25 years !

Stand: 7.9.2017