文档介绍：Source: STANDARD HANDBOOK OF MACHINE DESIGN
CHAPTER 1
EVOLUTION OF
A ESSFUL DESIGN
Thomas H. Brown, Jr., ., .
Faculty Associate
Institute for Transportation Research and Education
North Carolina State University
Raleigh, North Carolina
EVOLUTION OF A DESIGN /
USING THE HANDBOOK /
SOME OPPORTUNITIES TO DISCOVER /
FINAL THOUGHTS /
EVOLUTION OF A DESIGN
Most likely you have, right at this moment, at least one machine design project in
progress. Maybe you were the originator of the design, but I suspect you inherited
this design from others. I further suspect that you have already identified elements
of the design you feel could be improved. You might be under pressure from cus-
tomer service or marketing to respond to some need for change. In responding suc-
cessfully, either to your own observations for change or to those of others, the design
will evolve. Recognizing that the evolutionary design process is plex,
with a seemingly random sequence of steps, the primary purpose of Standard Hand-
book of Machine Design is to make the information you need as readily accessible
and usable as possible.
As an example of how a design can evolve, and to provide perspective on how the
information in this Handbook has traditionally been used, let me review for you a
project I was given in my first job as a mechanical engineer. It involved the position-
ing of a microwave feed horn for a 30-ft-diameter antenna dish. The original design
(not mine, by the way) called for a technician to climb up onto a platform, some 20
ft off the ground, near the backside of the feed horn. The technician had to loosen a
half dozen bolts, rotate the feed horn manually, and then retighten the bolts. This
design worked quite well until several systems were sold to a customer providing
munications along the Alaskan oil pipeline. Workers were not really safe
going out in below 0°F weather, with