Franz Reuleaux (; ; 30 September 1829 – 20 August 1905), was a German

mechanical engineer Mechanical may refer to: Machine * Machine (mechanical), a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement * Mechanical calculator, a device used to perform the basic operations of ...

and a lecturer of the

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Royal Technical Academy, later appointed as the President of the Academy. He was often called the father of kinematics. He was a leader in his profession, contributing to many important domains of science and knowledge. Today, he may be best remembered for the Reuleaux triangle, a

curve of constant width In geometry, a curve of constant width is a simple closed curve in the plane whose width (the distance between parallel supporting lines) is the same in all directions. The shape bounded by a curve of constant width is a body of constant width ...

that he helped develop as a useful mechanical form.

Biography

Early life

Reuleaux was born in

Eschweiler Eschweiler (, Ripuarian: ) is a municipality in the district of Aachen in North Rhine-Westphalia in Germany on the river Inde, near the German-Belgian-Dutch border, and about east of Aachen and west of Cologne. History * Celts (fi ...

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(at the time part of

Prussia Prussia, , Old Prussian: ''Prūsa'' or ''Prūsija'' was a German state on the southeast coast of the Baltic Sea. It formed the German Empire under Prussian rule when it united the German states in 1871. It was ''de facto'' dissolved by an ...

). His father and grandfather were both machine builders. His technical training was at the Karlsruhe Polytechnic School. He then studied at universities in Berlin and Bonn.

Middle years

After a time spent in the family business he became a professor at the Swiss Federal Institute in Zurich. Eventually, in 1879 he became Rector at the Königs Technischen Hochschule Berlin – Charlottenburg. This was a major technical institute, with about 300 professors. He became widely known as an engineer-scientist — a professor and industrial consultant, education reformer and leader of the technical elite of Germany. Reuleaux was the appointed chairman of the German panel of judges for the Sixth World Industrial Fair opened in

Philadelphia Philadelphia, often called Philly, is the List of municipalities in Pennsylvania#Municipalities, largest city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, the List of United States cities by population, sixth-largest city i ...

on 10 May 1876. He admitted that German-made goods were far inferior to those of other countries and that German industry's guiding principle was “billig und schlecht” ( English: cheap and shoddy). This shook business and evoked wide comment in the press. Reuleaux was a consultant to the development of the Otto-Langen internal combustion engine, winner of the 1867 World's Fair in Paris, France, based on efficiency. Reuleaux served on several international juries and commissions and considerably involved in formation of a

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A ...

system, as he was active in German politics. In 1877, he was elected as a member of the

American Philosophical Society The American Philosophical Society (APS), founded in 1743 in Philadelphia, is a scholarly organization that promotes knowledge in the sciences and humanities through research, professional meetings, publications, library resources, and communit ...

. He was a member of the Royal Swedish Academy of Sciences from 1882.

Kinematics

Reuleaux believed that machines could be abstracted into chains of elementary links called

kinematic pair In classical mechanics, a kinematic pair is a connection between two physical objects that imposes constraints on their relative movement (kinematics). German engineer Franz Reuleaux introduced the kinematic pair as a new approach to the study ...

s. Constraints on the machine are described by constraints on each kinematic pair, and the sequence of movements of pairs produces a kinematic chain. He developed a compact symbolic notation to describe the topology of a very wide variety of mechanisms, and showed how it could be used to classify them and even lead to the invention of new useful mechanisms. At the expense of the German government, he directed the design and manufacture of over 300 beautiful models of simple mechanisms, such as the

four-bar linkage In the study of mechanisms, a four-bar linkage, also called a four-bar, is the simplest closed-chain movable linkage. It consists of four bodies, called ''bars'' or ''links'', connected in a loop by four joints. Generally, the joints are config ...

and the crank. These were sold to universities for pedagogical purposes. Today, the most complete set are at

Cornell University Cornell University is a private statutory land-grant research university based in Ithaca, New York. It is a member of the Ivy League. Founded in 1865 by Ezra Cornell and Andrew Dickson White, Cornell was founded with the intention to tea ...

College of Engineering.The kinematic models for design digital library
/ref> Using his notation and methods for systematically varying the elements (e.g. inversions, changing relative sizes of the links, etc.) he showed how the four-bar linkage could be mutated into 54 mechanisms, which fall within 12 classes.

Books by Franz Reuleaux

*''Kinematics of Machinery'' (1875)
ebook
*''The Constructor'' (1861)
ebook
*''Kurzgefasste Geschichte der Dampfmaschine'' (1891) *''Thomassche Rechenmaschine'' (2d ed. 1892)

Notes

References

*Bragastini, Roberto ''Contributo per una interpretazione filosofica dell'opera di Franz Reuleaux'', Università degli Studi di Milano (Milan, 2003). *Moon, Francis "Franz Reuleaux: Contributions to 19th Century Kinematics and Theory of Machines". * *

External links

Kinematic Models for Design Digital Library (KMODDL)
br /> Movies and photos of hundreds of working mechanical-systems models at Cornell University. Also includes a
e-book library
of classic texts on mechanical design and engineering.
Reproductions of Franz Reuleaux's Kinematic Models
br /> Modern reproductions of the kinematic models as originally produced. {{DEFAULTSORT:Reuleaux, Franz 1829 births 1905 deaths People from Eschweiler German mechanical engineers Members of the Royal Swedish Academy of Sciences ETH Zurich faculty Engineers from North Rhine-Westphalia