19th c. Olivier String Models at Cornell University: Ruled Surfaces in Gear Design

摘要

This paper describes a newly discovered collection of 19th c. Olivier string models for descriptive geometry at Cornell University, Ithaca, NY, USA. String models illustrating concepts of descriptive geometry were employed in the 19th and early 20th centuries as teaching and visualization aids for engineering, architecture and mathematics. The carefully crafted "Olivier models" are composed of finished wooden bases, brass armatures and colored threads and have an inherent beauty. They illustrate a variety of ruled surfaces - cylinders, hyperboloids, cones, conoids, planes and hyperbolic paraboloids (hypars) - and their intersections. The models not only served to enhance mathematical and drawing skills but also inspired designers and artists. Such inspiration is evident for both the design of mechanisms for machines and for the creation of 20th century sculpture. It is believed the models were copied after the historic original Olivier Models at Union College circa 1884.