Mathematisches Modell
The theorem of Roberts on three-bar motion
Kurzbeschreibung: The model illustrates the theorem of Roberts, which says that to any given link quadrilateral with a certain three-bar curve two further quadrilaterals can be found which have the same three-bar curve. In his below mentioned paper A. Cayley gives the following construction, how to find a given link quadrilateral OABM with the coupled triangle ABC the two other link quadrilaterals, that have all the same three-bar curve. In the given figure the parallelograms OACD and BMFC are drawn. Over the sides DC and CF two trinagles are constructed, which are similar to the triangle ABC, such that for their angles holds: angle CDE = angle FCG = angle BAC, and angle DCE = angle CFG = angle ABC. By drawing the parallelogram ECGN one gets the third fixed point N. These three link quadrilaterals that force the point C on the same three-bar curve are marked by different colours in the model.
- Location
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Technische Universität Dresden, Institut für Geometrie
- Collection
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Mathematische Modelle, Technische Universität Dresden
- Other number(s)
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97612-000 (Objektnummer)
907/204 (Katalognummer)
- Measurements
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40 x 49 x 6 (in cm)
1750 (in g)
- Material/Technique
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Metal lacquered
- Classification
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Kinematics (Fachgebiet)
- Event
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Herstellung
- (who)
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Stoll (Hersteller)
- Event
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Sammeltätigkeit
- (when)
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23.09.1959
- Last update
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25.03.2025, 11:48 AM CET
Data provider
Institut für Geometrie der Technischen Universität Dresden. If you have any questions about the object, please contact the data provider.
Object type
- Mathematisches Modell
Associated
Time of origin
- 23.09.1959