Introduction 3
geometry concept are reproduced in the actual structure without noticeable
error.
The scope of the book means that it alone is not complete in a practical
engineering sense. To arrive at the final design of a motion structure, one
must decide plenty of details not covered by this book. For instance, one
must choose materials, carry out structural analysis for a series of configurations subjected to the expected loadings, consider influences of dynamic
loadings such as inertia, and decide other dimensions of the components,
how the members are manufactured and assembled and how the motion
structures are to be serviced including lubrication of the bearings and
design of their clearances to ensure that the mechanism will remain
throughout its working life strong enough and stiff enough to withstand
all the forces it will experience.
The design of motion structures remains an iterative process despite the
best efforts of the authors and many fellow engineers. However, it remains
to be our strong belief that if the scope of motion structures is to be
extended, engineers who create such structures must become familiar with
theoretical methods of synthesis, with criteria which must be obeyed and
with general principles of motion which can always provide shortcuts
across the tedious processes of identifying a starting concept. A sound
knowledge in mechanisms, combined with common sense and intuition,
can contribute to the production of many more efficient motion structures.