Johann Heinrich Ehrhardt

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Johann Heinrich Ehrhardt , also Erhardt , (born April 29, 1805 in Zella St. Blasii , † April 29, 1883 in Radebeul ) was a German locomotive builder and inventor .

Live and act

The son of a poor gunsmith began his professional life as a day laborer, working as an independent wire drawer in the Jäger wire drawing works. During a visit by a master gunsmith to his parents' house, he became aware of the son's manual skills and enabled Ehrhardt to do an apprenticeship as a gunsmith . The finished journeyman got his first job in the mint in Gotha .

LE BELGE

Ehrhardt went to Belgium in 1831 with recommendations from his mint master. He only worked for an optician in Brussels for six months before he was able to go to John Cockerill's machine factory in Seraing to work in steam engine construction. As a fitter of dewatering machines , he invented a rear loading chamber there. Ehrhardt switched to Cockerill's locomotive construction, headed by Konrad Gustav Pastor , when preparations began in 1833 for the construction of his first LE BELGE steam locomotive, based on the model of Stephenson's ROCKET locomotive in continental Europe . With two of Stephenson's own locomotives ( LE FLÈCHE [French: THE PFEIL ] and STEPHENSON ) the Brussels – Mechelen line was to be opened. In November 1833, Ehrhardt went to the Polytechnic in Düsseldorf in order to acquire theoretical knowledge for the upcoming work . Three months later he left it with the "Certificate No. 1 by Prof. Carl Schäfer ”. In order to be able to open the railway line with two locomotives, twelve test drives were planned for each locomotive from July 1834 onwards by Ehrhardt, followed by the acceptance by the royal commission. Robert Stephenson carried out the acceptance test personally on August 2, 1834, Ehrhardt accompanied him in the driver's cab. Halfway to Mechelen, the locomotive derailed "as a result of maliciously tearing open the rails". The Stephenson locomotive was not damaged. In 1835 Ehrhardt then assembled the LE BELGE , the first steam locomotive made in continental Europe. This began regular traffic at the end of 1835.

In 1836 Ehrhardt attended the art and trade school in Düsseldorf to expand his theoretical knowledge as well as his skills in technical drawing. Then he returned to his home in Zella.

Products of the Saxon Mechanical Engineering Compagnie

According to a source, Ehrhardt met one of the directors of the Sächsische Maschinenbau-Compagnie in Chemnitz during a visit to a trade fair in Leipzig in October 1838 , and he immediately engaged him to build steam engines and locomotives. According to another source, Ehrhardt's brother worked as an engraver for the publisher Friedrich Brockhaus in Leipzig. He told him about the experiences of his brother who was looking for work. Brockhaus had acquired a stake in the Sächsische Maschinenbau-Compagnie in Chemnitz and was interested in the reorganization of the business activities that followed the takeover of the company from Carl Gottlieb Haubold in 1836. Since Brockhaus was planning to start building locomotives there, he had a conversation with Ehrhardt and then sent him with a letter of recommendation to Director Kaden in Chemnitz to check whether the plant was suitable for locomotive construction. The report was very sobering. The technical director of the Sächsische Maschinenbau-Compagnie, Justus Preuss, hired Ehrhardt because he was not satisfied with the then head of locomotive construction, director Friedrich Overmann.

Shortly afterwards, on October 14, 1838, before he started work, Ehrhardt transported the STURM model locomotive , which he had bought from Kirtley in Warrington / England , over country roads from Leipzig to Chemnitz. This led to the first dispute between Ehrhardt and Overmann. After further disputes with this, Ehrhardt persuaded his advocate Brockhaus that Overmann lost his responsibility for locomotive construction. As a foreman, Ehrhardt rebuilt the planned assembly area according to his own ideas and reordered some of the parts that had already been delivered by the company's own foundry due to quality defects, this time from the Jacobi brothers in Buschbad near Meißen . Ehrhardt later redesigned the company's own foundry. Then, under Ehrhardt's assembly management, the two only locomotives built by this company, TEUTONIA and PEGASUS , were built in 1839/1840 , according to Ehrhardt's statement, according to the constructive plans of Director Preuss. The TEUTONIA was intended for the Magdeburg-Leipzig Railway Company , but could not be put into operation by the latter for its railway line because it was too heavy for their superstructure. Instead, the locomotive could be sold to the Magdeburger-Dampfschiffahrts-Compagnie , which converted it into a ship's engine. The PEGASUS was acquired after a one-year trial period by the Leipzig-Dresden Railway Company , which operated it on its route until 1861. The verdict on Ehrhardt in the Deutsche Gewerbezeitung was positive: "The work on the locomotives was excellent, the machines, pumps and the like worked as well as they could have been hoped for." Since further projects were unsuccessful, the postponed Compagnie built boilers until it went bankrupt in 1852.

Ehrhardt scales
Ehrhardt locomotive cylinder drilling machine

From 1843 to 1868 Ehrhardt was chief engineer (“Obermaschinenmeister was the name of the current secret construction officer, everything technical revolved around him”) in the service of the Saxon-Silesian Railway Company or, after its nationalization in 1851, of the Saxon State Railways in Dresden . He made many contributions to the railway system. He invented the two-sided brakes with oscillating shafts (1847) and the transportable Ehrhardt scales for controlling the axle loads of vehicles (Patent No. 71: Apparatus for controlling the loading of locomotives, tenders and car axles , 1879). From the patented in many countries, first pioneered control machinery that built Saxon machine factory of Richard Hartmann 1865 to 1873 a total of 1,235 pieces; Royalties went to Ehrhardt, for which Ehrhardt had received support from his friend Louis Schönherr , a rival of Hartmann. Ehrhardt also provided the reversible cast steel frogs for switches and crossings as well as the brackets that encompass the rail foot. He made contributions to the improvement of Adam's bow springs and preheat condensation devices. In addition, there are maintenance devices such as the locomotive cylinder drill. "He is considered the old master of the railway industry ."

His list of students with 18 names includes later machine masters from other railway companies and professors from the Chemnitz business school and the Freiberg mining academy as well as factory owners and directors of important German and Austrian machine and textile factories.

Ehrhardt's nephew Heinrich Ehrhardt (1840–1928) was also a successful inventor, as well as an industrialist and entrepreneur.

In 1869 Ehrhardt retired in Radebeul, Saxony , where he died in 1883 at the age of 78.

literature

Individual evidence

  1. ↑ a b Jochen Haeusler: The Ehrhardt family from Zella or how did the locomotive know-how come to Chemnitz? ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The @1@ 2Template: Webachiv / IABot / www.saechsisches-industriemuseum.de archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . In: Museum Courier - Issue 18 - December 2006.
  2. ↑ a b c d e Museum courier of the Chemnitz industrial museum and its support association. June 2009 ( Memento of the original from January 30, 2016 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF file; 4.64 MB)  @1@ 2Template: Webachiv / IABot / www.saechsisches-industriemuseum.de
  3. ^ Société Anonyme John Cockerill
  4. ↑ European Route of Industrial Heritage: John Cockerill on www.erih.net
  5. ^ Sächsische Maschinenbau-Compagnie
  6. ↑ Jochen Haeusler: The Ehrhardt family from Zella or how did the locomotive know-how come to Chemnitz? ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The @1@ 2Template: Webachiv / IABot / www.saechsisches-industriemuseum.de archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . In: Museumskurier - Issue 18 - December 2006 (statement based on an unpublished manuscript by Ehrhardt from the Chemnitz City Library).
  7. ↑ "The designer Carl August Rabenstein named in the specialist literature, one of the first teachers at the trade school and later founder of the Rabenstein & Co company in Chemnitz, does not appear in the manuscript [von Ehrhardt]."
  8. ^ Heinrich Ehrhardt : Hammer blows - 70 years of German workers and inventors. Verlag von KF Koehler, Leipzig 1922, p. 13 (Reprint Heinrich-Jung-Verlag, 2006, ISBN 3-930588-37-4 ).
  9. ^ JH Ehrhardt's improved scales for testing the load on railway axles. In: Polytechnisches Journal . 236, 1880, pp. 365-366.
  10. ↑ Ehrhardt's control apparatus for railway vehicles. In: Polytechnisches Journal . 178, 1865, pp. 432-434.
personal data
SURNAME Ehrhardt, Johann Heinrich
ALTERNATIVE NAMES Erhardt, Johann Heinrich
BRIEF DESCRIPTION German locomotive builder and inventor
DATE OF BIRTH April 29, 1805
PLACE OF BIRTH Zella St. Blasii
DATE OF DEATH April 29, 1883
Place of death Radebeul