CONTRIBUTIONS FROM
THE MUSEUM OF HISTORY AND TECHNOLOGY
PAPER 27
KINEMATICS OF MECHANISMS FROM THE TIME OF WATT
Eugene S. Ferguson
Contents
| JAMES WATT, KINEMATIC SYNTHESIST | 187 |
| TO DRAW A STRAIGHT LINE | 199 |
| SCHOLARS AND MACHINES | 209 |
| MECHANICIANS AND MECHANISMS | 216 |
| MECHANISMS IN AMERICA, 1875-1955 | 223 |
| ADDITIONAL REFERENCES | 229 |
KINEMATICS OF MECHANISMS FROM THE TIME OF WATT
In an inventive tour de force that seldom, if ever, has been equalledfor its brilliance and far-reaching consequences, James Watt radically alteredthe steam engine not only by adding a separate condenser but by creating a wholenew family of linkages. His approach was largely empirical, as we use the wordtoday.
This study suggests that, despite the glamor of today's sophisticatedmethods of calculation, a highly developed intuitive sense, reinforced by aknowledge of the past, is still indispensable to the design of successfulmechanisms.
THE AUTHOR: Eugene S. Ferguson, formerly curator of mechanical and civilengineering in the United States National Museum, Smithsonian Institution, isnow professor of mechanical engineering at Iowa State University of Science andTechnology.
In engineering schools today, a student is introduced to the kinematics ofmechanisms by means of a course of kinematic analysis, which is concerned withprinciples underlying the motions occurring in mechanisms. These principles aredemonstrated by a study of mechanisms already in existence, such as the linkageof a retractable landing gear, computing mechanisms, mechanisms used in anautomobile, and the like. A systematic, if not rigorous, approach to the designof gears and cams also is usually presented in such a course. Until recently,however, no serious attempt was made to apply the principles developed inkinematic analysis to the more complex problem of kinematic synthesis oflinkages. By kinematic synthesis is meant the designing of a linkage to producea given series of motions for a particular purpose.
That a rational—numerical or geometrical—approach to kinematic synthesis ispossible is a relatively recent idea, not yet fully accepted; but it is thisidea that is responsible for the intense scholarly interest in the kinematics ofmechanisms that has occurred in this country within the last 10 years.
This scholarly activity has resulted in the rediscovery of many earlier workson the subject, and nearly all the scholars now working in this field haveacknowledged in one way or another their debt to those who arrived on the sceneat an earlier time than they. There have been occasional reviews of the sequenceand nature of developments, but the emphasis naturally has been upon the rece