Positive Return Cam
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- Title:
- Positive Return Cam
- Title (German):
- Gleichseitiges Bogendreieck in schiefer Shleife mit Pohlbahn
- Collection:
- Reuleaux Kinematic Mechanisms Collection
- Set:
- L. Positive Return Constant Breadth Cams
- Designer:
- Reuleaux, F. (Franz), 1829-1905
- Manufacturer:
- Gustav Voigt Werkstatt
- Date:
- 1882
- Country:
- Germany
- Voigt Catalog Model:
- L2
- File Name:
- L02.jpg
- Work Type:
- Mechanical model
- Materials/Techniques:
- cast iron and brass on wood pedestal
- Subject:
- Kinematics of Machinery
- Measurement:
- 198 x 89 (millimeters, width x depth)
264 x 117 x 204 (millimeters, width x depth x height) - Description:
- This positive return cam mechanism is a practical application of curves of constant width as shown in models B2,B3,B4. The curved equilateral triangle has been called by several mathematicians, a Reuleaux Triangle, because Reuleaux was the first to present an extensive discussion and analysis of these curves in his 1875 book on Theoretical Kinematics. However this particular cam can be found in an 1820's steam engine in the Science Museum in London. It was used to control the entrance and exit of steam into the cylinder chamber. The "Reuleaux Triangle" cam moves a valve and has a pause or dwell in the motion. It is likely that this device was discovered by several inventors perhaps as early as the time of the first Watt engines in the late 18th century. However ingenious this mechanism, it has all but been forgotten by engineers in the early 21st century. In this mechanism, the parallel guides are at an incline that changes the phase of the dwell period. See discussion in B2. [Francis Moon 2003-05-29]
The 220 models in Cornell University’s Reuleaux Collection were built in the late 19th century to demonstrate the elements of machine motion, as theorized by the German engineer Franz Reuleaux. The University acquired the models in 1882 for use in teaching and research. The Reuleaux models are classified according to the alphanumeric schema employed in the catalog of the manufacturer, Gustav Voigt. The letter in a model's ID (e.g., B14 or S35) refers to a class of mechanism; the number is a specific instance of the class. This classification scheme is a simplified version of the taxonomy of machine elements elaborated in Reuleaux's work. - Repository:
- Sibley School of Mechanical and Aerospace Engineering, Cornell University
- Format:
- Image
- Rights:
- Photography credit: Jon Reis (www.jonreis.com). Jon Reis Photography grants Cornell University Libraries and the Cornell College of Engineering the rights to display copyrighted images of the Reuleux collection of kinetic machines on the Cornell University and National Science Digital Library web sites and for unlimited use in Cornell University Library publications for education purposes only. Rights for all other uses, including but not limited to, editorial, commercial, advertising, web use and display by third parties not affiliated with Cornell University are reserved by the photographer. The written permission of any copyright and other rights holders is required for distribution, reproduction, or other use that extends beyond what is authorized by fair use and other statutory exemptions. Responsibility for making an independent legal assessment of an item and securing any necessary permissions ultimately rests with persons desiring to use the item. For questions about this item or other items please contact the Physical Sciences Librarians at pslref@cornell.edu.