eCommons Collection: History and Theory of Machines and Mechanisms

Historical Mechanisms for Drawing Curves

Tue, 20 Apr 2004 22:58:59 GMT

Title: Historical Mechanisms for Drawing Curves

Authors: Taimina, Daina

Abstract: Mechanical devices such as linkages for drawing curves are known already from Ancient Greece. Later linkages found use in different mechanical devices and machines like we can see it in 13th century drawings by Honnecourt or in 16th century machine drawings by Agricola. In 17th century Descartes accepted only those curves that had a mechanical device to draw them. Mechanical curve drawing devices later became incorporated into different machine design. In this paper examples from Reuleaux kinematic model collection in Cornell University are given and some history of linkages discussed.

Usability, Learning, and Subjective Experience: User Evaluation of

Thu, 26 Feb 2004 22:58:59 GMT

Title: Usability, Learning, and Subjective Experience: User Evaluation of

Authors: Pan, Bing; Gay, Geri; Saylor, John; Hembrooke, Helene; Henderson, David

Abstract: This paper describes an evaluation effort of the use of the Kinematic Model for Design Digital Library (K-MODDL) in an undergraduate mathematics class. Based on CIAO! framework, the research revealed usability problems and users? subjective experience when using K-MODDL, confirmed the usefulness of various physical and digital models in facilitating learning, and revealed interesting relationships among usability, learning, and subjective experience.

How to Use History to Clarify Common Confusions in Geometry

Wed, 14 May 2003 22:58:59 GMT

Title: How to Use History to Clarify Common Confusions in Geometry

Authors: Taimina, Daina; Henderson, David W.

Abstract: We have found that students and even mathematicians are often confused about the history of geometry. Many expository descriptions of geometry (especially non-Euclidean geometry) contain confusing and sometimes-incorrect statements. Therefore, we found it very important to give some historical perspective of the development of geometry, clearing up many common misconceptions. In this paper we use history to clarify the following questions, which often have confusing or misleading (or incorrect) answers: 1. What is the first non-Euclidean geometry? 2. Does Euclid's parallel postulate distinguish the non-Euclidean geometries from Euclidean geometry? 3. Is there a potentially infinite surface in 3-space whose intrinsic geometry is hyperbolic? 4. In what sense are the Models of Hyperbolic Geometry 'models'? 5. What does 'straight' mean in geometry? How can we draw a straight line? We noticed that most confusions related to the above questions come from not recognizing certain strands in the history of geometry. The main aspects of geometry today emerged from four strands of early human activity that seem to have occurred in most cultures: art/patterns, building structures, motion in machines, and navigation/stargazing. These strands developed more or less independently into varying studies and practices that eventually from the 19th century on were woven into what we now call geometry. In this paper we describe how these strands can be used to clarify issues surrounding these questions.

3D-Printing the History of Mechanisms

Wed, 30 Jul 2003 22:58:59 GMT

Title: 3D-Printing the History of Mechanisms

Authors: Lipson, Hod; Moon, Francis C.; Hai, Jimmy; Paventi, Carlo

Abstract: Physical models of machines have played an important role in the history of engineering for teaching, analyzing, and exploring mechanical concepts. Many of these models have been replaced today by computational representations, but new rapid-prototyping technology allows reintroduction of physical models as an intuitive way to demonstrate mechanical concepts. This paper reports on the use of computer-aided modeling tools and rapid prototyping technology to document, preserve, and reproduce in three dimensions, historic machines and mechanisms. We have reproduced several pre-assembled, fully-functional historic mechanisms such as early straight line mechanisms, ratchets, pumps, and clock escapements, including various kinematic components such as links, joints, gears, worms, nuts, bolts, and springs. The historic mechanisms come from the Cornell Collection of Reuleaux Kinematic Models as well as models based on the work of Leonardo da Vinci. The models are available as part of a new online museum of mechanism, which allows visitors not only to read descriptions and view pictures and videos, but now also download, 3D-print and interact with their own physical replicas. Our aim in this paper is to demonstrate the ability of this technology to reproduce accurate historical kinematic models and machines as a tool for both artifact conservancy as well as for teaching, and to demonstrate this for a wide range of mechanism types. We expect that this new form of ?physical? preservation will become prevalent in future archives. We describe the background and history of the collection as well as aspects of modeling and printing such functional replicas.