Mechanisms and mechnical devices sourcebook

MECHANISMS AND

MECHANICAL DEVICES

SOURCEBOOK

Fifth Edition

NEIL SCLATER

McGraw-Hill

New York • Chicago • San Francisco • Lisbon • London • Madrid

Mexico City • Milan • New Delhi • San Juan • Seoul

Singapore • Sydney • Toronto

Copyright © 2011, 2007, 2001, 1996, 1991 by The McGraw-Hill Companies, Inc. All rights reserved. Except as permitted under the United States Copyright Act

of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior

written permission of the publisher.

ISBN: 978-0-07-170441-0

MHID: 0-07-170441-8

The material in this eBook also appears in the print version of this title: ISBN: 978-0-07-170442-7,

MHID: 0-07-170442-6.

All trademarks are trademarks of their respective owners. Rather than put a trademark symbol after every occurrence of a trademarked name, we use names in an

editorial fashion only, and to the benefi t of the trademark owner, with no intention of infringement of the trademark. Where such designations appear in this book,

they have been printed with initial caps.

McGraw-Hill eBooks are available at special quantity discounts to use as premiums and sales promotions, or for use in corporate training programs. To contact a

representative please e-mail us at [email protected].

Information contained in this work has been obtained by The McGraw-Hill Companies, Inc. (“McGraw-Hill”) from sources believed to be reliable. However,

neither McGraw-Hill nor its authors guarantee the accuracy or completeness of any information published herein, and neither McGraw-Hill nor its authors shall

be responsible for any errors, omissions, or damages arising out of use of this information. This work is published with the understanding that McGraw-Hill and

its authors are supplying information but are not attempting to render engineering or other professional services. If such services are required, the assistance of an

appropriate professional should be sought.

TERMS OF USE

This is a copyrighted work and The McGraw-Hill Companies, Inc. (“McGrawHill”) and its licensors reserve all rights in and to the work. Use of this work is subject

to these terms. Except as permitted under the Copyright Act of 1976 and the right to store and retrieve one copy of the work, you may not decompile, disassemble,

reverse engineer, reproduce, modify, create derivative works based upon, transmit, distribute, disseminate, sell, publish or sublicense the work or any part of it

without McGraw-Hill’s prior consent. You may use the work for your own noncommercial and personal use; any other use of the work is strictly prohibited. Your

right to use the work may be terminated if you fail to comply with these terms.

THE WORK IS PROVIDED “AS IS.” McGRAW-HILL AND ITS LICENSORS MAKE NO GUARANTEES OR WARRANTIES AS TO THE ACCURACY,

ADEQUACY OR COMPLETENESS OF OR RESULTS TO BE OBTAINED FROM USING THE WORK, INCLUDING ANY INFORMATION THAT CAN

BE ACCESSED THROUGH THE WORK VIA HYPERLINK OR OTHERWISE, AND EXPRESSLY DISCLAIM ANY WARRANTY, EXPRESS OR IMPLIED,

INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. McGraw-Hill

and its licensors do not warrant or guarantee that the functions contained in the work will meet your requirements or that its operation will be uninterrupted or

error free. Neither McGraw-Hill nor its licensors shall be liable to you or anyone else for any inaccuracy, error or omission, regardless of cause, in the work or for

any damages resulting therefrom. McGraw-Hill has no responsibility for the content of any information accessed through the work. Under no circumstances shall

McGraw-Hill and/or its licensors be liable for any indirect, incidental, special, punitive, consequential or similar damages that result from the use of or inability

to use the work, even if any of them has been advised of the possibility of such damages. This limitation of liability shall apply to any claim or cause whatsoever

whether such claim or cause arises in contract, tort or otherwise.

iii

CONTENTS

PREFACE xi

CHAPTER 1 BASICS OF MECHANISMS 1

Introduction 2

Physical Principles 2

Efficiency of Machines 2

Mechanical Advantage 2

Velocity Ratio 3

Inclined Plane 3

Pulley Systems 3

Screw-Type Jack 4

Levers and Mechanisms 4

Levers 4

Winches, Windlasses, and Capstans 5

Linkages 5

Simple Planar Linkages 5

Specialized Linkages 6

Straight-Line Generators 7

Rotary/Linear Linkages 8

Specialized Mechanisms 9

Gears and Gearing 10

Simple Gear Trains 11

Compound Gear Trains 11

Gear Classification 11

Practical Gear Configurations 12

Gear Tooth Geometry 13

Gear Terminology 13

Gear Dynamics Terminology 13

Pulleys and Belts 14

Sprockets and Chains 14

Cam Mechanisms 14

Classification of Cam Mechanisms 15

Cam Terminology 17

Clutch Mechanisms 17

Externally Controlled Friction Clutches 17

Externally Controlled Positive Clutches 17

Internally Controlled Clutches 18

Glossary of Common Mechanical Terms 18

CHAPTER 2 MOTION CONTROL SYSTEMS 21

Motion Control Systems Overview 22

Glossary of Motion Control Terms 28

Mechanical Components Form Specialized Motion-Control Systems 29

Servomotors, Stepper Motors, and Actuators for Motion Control 30

Servosystem Feedback Sensors 38

Solenoids and Their Applications 45

CHAPTER 3 STATIONARY AND MOBILE ROBOTS 49

Introduction to Robots 50

The Robot Defined 50

Stationary Autonomous Industrial Robots 50

Some Robot History 51

The Worldwide Robot Market 51

Industrial Robots 51

Industrial Robot Advantages 52

Industrial Robot Characteristics 53

Industrial Robot Geometry 53

Four Different ABB Industrial Robots 56

IRB 2400 57

IRB 6400RF 57

IRB 6640 57

IRB 7600 57

Autonomous and Semiautonomous Mobile Robots 58

Options for Communication and Control 58

Land-based Mobile Robots Can Scout and Retrieve 58

Submersible Mobile Robots Can Search and Explore 58

Robotic Aircraft (Drones) Can Search and Destroy 58

Planetary Exploration Robots Can Examine and Report 59

Laboratory/Scientific Robots Can Mimic Human Behavior 59

Commercial Robots Can Deliver and Retrieve Goods 59

Consumer Robots Clean Floors and Mow Lawns 59

Some Robots Entertain or Educate 59

Seven Mobile Autonomous and Semiautonomous Robots 60

Two Robots Have Explored Mars for Six Years 60

This Robot Will Carry on the Work of Spirit and Opportunity 61

This Robot Responds to Civil Emergencies 62

Robot Delivers Hospital Supplies 62

A Military Remotely-Piloted Aircraft Can Observe and Attack the Enemy 63

Submarine Robot Searches for Underwater Mines and Obstructions 64

This System Offers Less Intrusive Surgery and Faster Recovery 65

Glossary of Robotic Terms 66

Modified Four-Limbed Robot Is a Better Climber 68

Six-Legged Robot Crawls on Mesh in Lunar Gravity 69

Two Robots Anchor Another Traversing Steep Slopes 70

Six-Legged Robot Can Be Steered While Hopping 71

CHAPTER 4 MECHANISMS FOR RENEWABLE POWER

GENERATION 73

Overview of Renewable Energy Sources 74

Nuclear: The Unlikely Prime Renewable 74

Alternative Renewable Energy Sources 75

Baseload and Baseload Demand Power Plants 75

Windmills: Early Renewable Power Sources 75

Wind Turbines: Descendents of Windmills 76

Where Are Wind Turbines Located? 77

Concentrating Solar Thermal (CST) Systems 78

Parabolic Trough Mirror Solar Thermal (CST) Plants 78

Power-Tower Solar Thermal (CST) Plants 79

Linear Fresnel Reflector Thermal (CST) Plants 80

Parabolic Dish Stirling Solar Thermal (CST) Plants 81

How a Stirling Engine Works 82

The Outlook for CST Renewable Energy 83

iv

Harnessing Moving-Water Power 84

Tidal Electric Power Generation 84

Ocean-Wave Power Generation 84

Another Possible Mechanical Hydropower Solution 84

The Relative Costs of Renewable Energy 85

Glossary of Wind Turbine Terms 86

Renewable Energy Resources 87

CHAPTER 5 LINKAGES: DRIVES AND MECHANISMS 89

Four-Bar Linkages and Typical Industrial Applications 90

Seven Linkages for Transport Mechanisms 92

Five Linkages for Straight-Line Motion 95

Six Expanding and Contracting Linkages 97

Four Linkages for Different Motions 98

Nine Linkages for Accelerating and Decelerating Linear Motions 99

Twelve Linkages for Multiplying Short Motions 101

Four Parallel-Link Mechanisms 103

Seven Stroke Multiplier Linkages 103

Nine Force and Stroke Multiplier Linkages 105

Eighteen Variations of Differential Linkage 107

Four-Bar Space Mechanisms 109

Seven Three-Dimensional Linkage Drives 111

Thirteen Different Toggle Linkage Applications 116

Hinged Links and Torsion Bushings Soft-Start Drives 118

Eight Linkages for Band Clutches and Brakes 119

Design of Crank-and-Rocker Links for Optimum Force Transmission 121

Design of Four-Bar Linkages for Angular Motion 124

Multibar Linkages for Curvilinear Motions 125

Roberts’ Law Helps to Design Alternate Four-Bar Linkages 128

Design of Slider-Crank Mechanisms 129

CHAPTER 6 GEARS: DEVICES, DRIVES, AND MECHANISMS 131

Gears and Eccentric Disk Provide Quick Indexing 132

Odd-Shaped Planetary Gears Smooth Stop and Go 133

Cycloid Gear Mechanism Controls Pump Stroke 136

Gears Convert Rotary-to-Linear Motion 137

Twin-Motor Planetary Gears Offer Safety and Dual-Speed 137

Eleven Cycloid Gear Mechanisms 138

Five Cardan-Gear Mechanisms 141

Controlled Differential Gear Drives 143

Flexible Face-Gears Are Efficient High-Ratio Speed Reducers 144

Rotary Sequencer Gears Turn Coaxially 145

Planetary Gear Systems 146

Noncircular Gears Are Balanced for Speed 153

Sheet-Metal Gears, Sprockets, Worms, and Ratchets for Light Loads 157

Thirteen Ways Gears and Clutches Can Change Speed Ratios 159

Gear and Clutch Shifting Mechanisms 161

Twinworm Gear Drive Offers Bidirectional Output 163

Bevel and Hypoid Gear Design Prevents Undercutting 164

Machining Method to Improve Worm Gear Meshing 165

Geared Speed Reducers Offer One-Way Output 166

Design of Geared Five-Bar Mechanisms 167

Equations for Designing Geared Cycloid Mechanisms 171

Design Curves and Equations for Gear-Slider Mechanisms 174

v

CHAPTER 7 CAM, GENEVA, AND RATCHET DRIVES

AND MECHANISMS 179

Cam-Controlled Planetary Gear System 180

Five Cam-Stroke-Amplifying Mechanisms 181

Cam-Curve-Generating Mechanisms 182

Fifteen Different Cam Mechanisms 188

Ten Special-Function Cams 190

Twenty Geneva Drives 192

Six Modified Geneva Drives 196

Kinematics of External Geneva Wheels 198

Kinematics of Internal Geneva Wheels 201

Star Wheels Challenge Geneva Drives for Indexing 205

Ratchet-Tooth Speed-Change Drive 208

Modified Ratchet Drive 208

Eight Toothless Ratchets 209

Analysis of Ratchet Wheels 210

CHAPTER 8 CLUTCHES AND BRAKES 211

Twelve Clutches with External or Internal Control 212

Spring-Wrapped Clutch Slips at Preset Torque 214

Controlled-Slip Expands Spring Clutch Applications 216

Spring Bands Improve Overrunning Clutch 217

Slip and Bidirectional Clutches Combine to Control Torque 218

Slip Clutches Serve Many Design Functions 219

Walking Pressure Plate Delivers Constant Torque 220

Seven Overrunning Clutches 221

One-Way Clutch Has Spring-Loaded Pins and Sprags 222

Roller Clutch Provides Two Output Speeds 222

Seven Overriding Clutches 223

Ten Applications for Overrunning Clutches 225

Eight Sprag Clutch Applications 227

Six Small Clutches Perform Precise Tasks 229

Twelve Different Station Clutches 231

Twelve Applications for Electromagnetic Clutches and Brakes 234

CHAPTER 9 LATCHING, FASTENING, AND CLAMPING

DEVICES AND MECHANISMS 237

Sixteen Latch, Toggle, and Trigger Devices 238

Fourteen Snap-Action Devices 240

Remote Controlled Latch 244

Toggle Fastener Inserts, Locks, and Releases Easily 245

Grapple Frees Loads Automatically 245

Quick-Release Lock Pin Has a Ball Detent 246

Automatic Brake Locks Hoist When Driving Torque Ceases 246

Lift-Tong Mechanism Firmly Grips Objects 247

Perpendicular-Force Latch 247

Two Quick-Release Mechanisms 248

Shape-Memory Alloy Devices Release Latches 249

Ring Springs Clamp Platform Elevator into Position 250

Cammed Jaws in Hydraulic Cylinder Grip Sheet Metal 250

Quick-Acting Clamps for Machines and Fixtures 251

Nine Friction Clamping Devices 253

Detents for Stopping Mechanical Movements 255

Twelve Clamping Methods for Aligning Adjustable Parts 257

Spring-Loaded Chucks and Holding Fixtures 259

vi

CHAPTER 10 CHAIN AND BELT DEVICES AND MECHANISMS 261

Twelve Variable-Speed Belt and Chain Drives 262

Belts and Chains Are Available in Many Different Forms 265

Change Center Distance without Altering Speed Ratio 269

Motor Mount Pivots to Control Belt Tension 269

Ten Roller Chains and Their Adaptations 270

Twelve Applications for Roller Chain 272

Six Mechanisms for Reducing Pulsations in Chain Drives 276

CHAPTER 11 SPRING AND SCREW DEVICES AND MECHANISMS 279

Flat Springs in Mechanisms 280

Twelve Ways to Use Metal Springs 282

Seven Overriding Spring Mechanisms for Low-Torque Drives 284

Six Spring Motors and Associated Mechanisms 286

Twelve Air Spring Applications 288

Novel Applications for Different Springs 290

Applications for Belleville Springs 291

Vibration Control with Spring Linkage 292

Twenty Screw Devices 293

Ten Applications for Screw Mechanisms 296

Seven Special Screw Arrangements 297

Fourteen Spring and Screw Adjusting Devices 298

A Long-Stroke, High-Resolution Linear Actuator 299

CHAPTER 12 SHAFT COUPLINGS AND CONNECTIONS 301

Four Couplings for Parallel Shafts 302

Links and Disks Couple Offset Shafts 303

Disk-and-Link Couplings Simplify Torque Transmission 304

Interlocking Space-Frames Flex as They Transmit Shaft Torque 305

Coupling with Off-Center Pins Connects Misaligned Shafts 307

Universal Joint Transmits Torque 45° at Constant Speed 308

Ten Universal Shaft Couplings 309

Nineteen Methods for Coupling Rotating Shafts 311

Five Different Pin-and-Link Couplings 315

Ten Different Splined Connections 316

Fourteen Ways to Fasten Hubs to Shafts 318

Polygon Shapes Provide Superior Connections 320

CHAPTER 13 MOTION-SPECIFIC DEVICES, MECHANISMS,

AND MACHINES 323

Timing Belts, Four-Bar Linkage Team Up for Smooth Indexing 324

Ten Indexing and Intermittent Mechanisms 326

Twenty-Seven Rotary-to-Reciprocating Motion and Dwell Mechanisms 328

Five Friction Mechanisms for Intermittent Rotary Motion 334

Nine Different Ball Slides for Linear Motion 336

Ball-Bearing Screws Convert Rotary to Linear Motion 338

Nineteen Arrangements for Changing Linear Motion 339

Eight Adjustable-Output Mechanisms 343

Four Different Reversing Mechanisms 345

Ten Mechanical Computing Mechanisms 346

Nine Different Mechanical Power Amplifiers 350

Forty-Three Variable-Speed Drives and Transmissions 353

Ten Variable-Speed Friction Drives 365

Four Drives Convert Oscillating Motion to One-Way Rotation 367

Eighteen Different Liquid and Vacuum Pumps 369

vii

Ten Different Pump Designs Explained 373

Glossary of Pump Terms 376

Bearingless Motor-Generators Have Higher Speed and Longer Life 377

Energy Exchange in Seawater Desalination Boosts Efficiency 378

Two-Cycle Engine Improves Efficiency and Performance 380

CHAPTER 14 PACKAGING, CONVEYING, HANDLING, AND

SAFETY MECHANISMS AND MACHINES 381

Fifteen Devices That Sort, Feed, or Weigh 382

Seven Cutting Mechanisms 386

Two Flipping Mechanisms 388

One Vibrating Mechanism 388

Seven Basic Parts Selectors 389

Eleven Parts-Handling Mechanisms 390

Seven Automatic-Feed Mechanisms 392

Fifteen Conveyor Systems for Production Machines 395

Seven Traversing Mechanisms for Winding Machines 399

Vacuum Pickup for Positioning Pills 401

Machine Applies Labels from Stacks or Rollers 401

Twenty High-Speed Machines for Applying Adhesives 402

Twenty-Four Automatic Mechanisms for Stopping Unsafe Machines 408

Six Automatic Electrical Circuits for Stopping Textile Machines 414

Six Automatic Mechanisms for Assuring Safe Machine Operation 416

CHAPTER 15 TORQUE, SPEED, TENSION, AND LIMIT

CONTROL SYSTEMS 419

Applications of the Differential Winch to Control Systems 420

Six Ways to Prevent Reverse Rotation 422

Caliper Brakes Keep Paper Tension in Web Presses 423

Control System for Paper Cutting 423

Warning System Prevents Overloading of Boom 424

Lever System Monitors Cable Tension 424

Eight Torque-Limiters Protect Light-Duty Drives 425

Thirteen Limiters Prevent Overloading 426

Seven Ways to Limit Shaft Rotation 429

Mechanical Systems for Controlling Tension and Speed 431

Nine Drives for Controlling Tension 435

Limit Switches in Machinery 438

Nine Automatic Speed Governors 442

Eight Speed Control Devices for Mechanisms 444

Cable-Braking System Limits Descent Rate 445

CHAPTER 16 INSTRUMENTS AND CONTROLS: PNEUMATIC,

HYDRAULIC, ELECTRIC, AND ELECTRONIC 447

Twenty-Four Mechanisms Actuated by Pneumatic or Hydraulic Cylinders 448

Foot-Controlled Braking System 450

Fifteen Tasks for Pneumatic Power 450

Ten Applications for Metal Diaphragms and Capsules 452

Nine Differential Transformer Sensors 454

High-Speed Electronic Counters 456

Applications for Permanent Magnets 457

Nine Electrically Driven Hammers 460

Sixteen Thermostatic Instruments and Controls 462

Eight Temperature-Regulating Controls 466

Seven Photoelectric Controls 468

viii

Liquid Level Indicators and Controllers 470

Applications for Explosive-Cartridge Devices 472

Centrifugal, Pneumatic, Hydraulic, and Electric Governors 474

CHAPTER 17 3D DIGITAL PROTOTYPES AND SIMULATION 477

Introduction to 3D Digital Prototypes and Simulation 478

A Short History of Engineering Drawing 478

Transition from Board to Screen 479

CAD Product Features 480

3D Digital Prototypes vs. Rapid Prototyping 480

The Ongoing Role of 2D Drawings 480

Functions of Tools in 3D Digital Prototype Software 481

File Types for 3D Digital Prototypes 481

Computer-Aided Engineering (CAE) 482

Simulation Software 482

Simulated Stress Analysis 483

Glossary of Computer-Aided Design Terms 484

CHAPTER 18 RAPID PROTOTYPING 487

Rapid Prototyping Focuses on Building Functional Parts 488

Rapid Prototyping Steps 489

Commercial Rapid Prototyping Choices 490

Commercial Additive RP Processes 491

Subtractive and R&D Laboratory Processes 498

CHAPTER 19 NEW DIRECTIONS IN MECHANICAL

ENGINEERING 501

The Role of Microtechnology in Mechanical Engineering 502

Micromachines Open a New Frontier for Machine Design 504

Multilevel Fabrication Permits More Complex and Functional MEMS 508

Electron Microscopes: Key Tools in Micro- and Nanotechnology 509

Gallery of MEMS Electron-Microscope Images 512

MEMS Actuators—Thermal and Electrostatic 516

MEMS Chips Become Integrated Microcontrol Systems 517

Alternative Materials for Building MEMS 519

LIGA: An Alternative Method for Making Microminiature Parts 520

The Role of Nanotechnology in Science and Engineering 521

Carbon: An Engineering Material with a Future 523

Nanoactuators Based on Electrostatic Forces on Dielectrics 528

The Lunar Electric Rover: A New Concept for Moon Travel 530

INDEX 533

ix

This page intentionally left blank.

xi

PREFACE

This is the fifth edition of a one-of-a-kind engineering reference book covering the past,

present, and future of mechanisms and mechanical devices. It includes clear illustrations

and straightforward descriptions of specific subjects rather than the theory and mathe￾matics found in most engineering textbooks. You will find that this book contains

hundreds of detailed line drawings that will hold your interest regardless of your back￾ground in mechanical engineering. The text accompanying the illustrations is intended

to help you to understand the basic concepts of subjects that may or may not be familiar

to you.

You will find drawings and illustrations that are simply interesting and informative

and perhaps others that could spur your creativity and prompt you to recycle them into

your new designs or redesigns. They may offer solutions you had not previously consid￾ered because they were not visible inside contemporary products unless the product is

disassembled. Solid state electronics and computer circuitry have displaced many earlier

mechanical solutions, no doubt improving product reliability and efficiency while reduc￾ing their price.

Nevertheless, many of those displaced mechanical components have lives of their own

and may very well turn up in other products in different form performing different func￾tions after undergoing dimensional and material transformations.

Classical, proven mechanisms and mechanical devices may seem to disappear only to

reappear in other forms and applications. Anyone who believes that all mechanisms will

be replaced by electronics need only examine the sophistication of the latest self-winding

mechanical watches, digital cameras, gyro-stabilized vehicles, and navigational systems.

This book illustrates the ongoing importance of classical mechanical devices as well as

the latest mechatronic devices formed by the merger between mechanics and electronics.

It is a must addition to your personal technical library, and it offers you a satisfying way

to “get up to speed” on new subjects or those you may have studied in the past but have

now faded from your memory. Moreover, it is hoped that this book will encourage you to

refresh your knowledge of these and other topics that interest you by accessing the many

related Web sites on the Internet.

What’s New in This Book?

This fifth edition contains three new chapters: Chapter 3, Stationary and Mobile Robots,

Chapter 4, Mechanisms for Renewable Power Generation, and Chapter 17, 3D Digital

Prototypes and Simulation. Chapter 18, Rapid Prototyping, has been updated and com￾pletely revised, and new articles have been added to Chapters 5 through 16 that make up

the archival core of the book. Five new articles have been added to Chapter 13, Motion￾Specific Devices, Mechanisms, and Machines, which is part of the archival core. Also, five

new articles have been added to Chapter 19, New Directions in Mechanical Engineering.

A Quick Overview of Some Chapters

Chapter 1 on basic mechanisms explains the physics of mechanisms including inclined

planes, jacks, levers, linkage, gears, pulleys, genevas, cams, and clutches—all compo￾nents in modern machines. A glossary of common mechanical terms is included.

Chapter 2 on motion control explains open- and closed-loop systems with diagrams

and text. Described and illustrated are the key mechanical, electromechanical, and elec￾tronic components that comprise modern automated robotic and mechatronic systems,

including actuators, encoders, servomotors, stepper motors, resolvers, solenoids, and

tachometers. It includes a glossary of motion control terms.

Chapter 3, a new discussion of robots, includes an overview of stationary industrial

robots and a wide range of mobile robots. Drawings and text explain the geometry of

industrial robots and leading specifications are given for four of the newest robots. Seven

mobile robots are described accompanied by their illustrations and leading specifications.

They operate on Mars, on Earth, in the air, and under the sea. Other articles describe

innovative NASA robots that climb, crawl, hop, and rappel down cliffs. In addition, a

glossary defines common robot terms.

Chapter 4, a new addition, describes the leading contenders for generating carbon-free

renewable power, which happen to be mechanical in nature. They are driven by the free

energy of the wind, sun, and natural water motion. Examples described and illustrated

include wind turbines and their farms, four different solar thermal farm concepts, and

proposed methods for tapping ocean tidal and wave energy. Both the upsides and down￾sides of these plants are stated. Attention is given to location, efficiency, public acceptance,

backup power sources, and connections to the power grid. Included is a glossary of wind

turbine terms.

Chapter 17, also new, explains the features of the latest computer software making it

possible to design new or revise old products in 3D right on the computer screen, taking

advantage of features including the ability to manipulate, “slice and dice,” and re￾dimension the virtual model in a range of colors to finalize the design complete with

manufacturing data. Compatible simulation software permits a model to be subjected to

virtual mechanical and multiphysics stresses to verify its design and choice of materials

without the need to build a physical model for testing. Included in the chapter is a glossary

of CAD/CAE terms.

Chapter 18, an update of an earlier chapter on rapid prototyping, explains and illus￾trates innovations and new additions to the many commercial additive and subtractive

processes for building 3D solid prototypes. They are being made from soft or hard mate￾rials for “hands-on” evaluation. Some prototypes are just for display while others are

built to withstand laboratory stress testing. However, the newer applications include the

fabrication of replacement parts for older machines, specialized metal tools, and molds

for casting.

Chapter 19 is an update of a collection of articles discussing cutting-edge topics in

mechanical engineering. These include the latest developments in microelectromechani￾cal devices (MEMS) and progress in developing practical applications for the carbon

allotropes, nanotubes, and graphene in products ranging from transparent sheets, strong

fiber, cable, capacitors, batteries, springs, and transistors. Other topics include electron

microscopes for R&D and a proposed long-range Moon rover.

The central core of the book, Chapters 5 through 16, contains an encyclopedic col￾lection of archival drawings and descriptions of proven mechanisms and mechanical

devices. This revised collection is a valuable resource for engineers, designers, teachers,

and students as well as enthusiasts for all things mechanical. New entries describe a pre￾cision linear actuator, polygon connections, slip clutches, shape memory alloy latches,

and an energy exchanger for making desalination more efficient.

A complete Index makes it easy for readers to find all of the references to specific

mechanisms, mechanical devices, components, and systems mentioned in the book.

Engineering Choices to Examine

Renewable Energy versus Fossil Fuel for Power Generation

The chapter on renewable power generation discusses three of the most promising

mechanical methods for generating carbon-free, grid-compatible electric power. Wind

turbine farms and concentrating solar thermal (CST) plants are the most likely candidates

for government subsidies. These technologies are described and illustrated, and their

upsides and downsides are explained. Electricity can also be generated by ocean waves

and tides, but these technologies lag far behind wind and solar thermal plants.

The U.S. government is offering financial incentives for building electrical generating

plants fueled by renewable energy, primarily for reducing atmospheric carbon dioxide

(CO

2) emissions, considered by some to be the principal source of manmade global

warming. The administration has set the goal of increasing the number of carbon-free,

non-hydro power plants from about 3 percent today to 20 percent by 2020. Wind and

solar thermal power plants have the best chance of meeting this goal, but many worry that

the building of these plants and eliminating many fossil-fueled plants could endanger the

utility industries’ efforts to meet the nation’s growing demand for low-cost, readily avail￾able electric power.

Renewable energy power sources are handicapped by the inability of the overbur￾dened power grid to transport electricity from remote parts of the country where most of

these installations will be located to metropolitan areas where electricity demand is highest.

When the wind dies or after sunset, these plants must be able to provide backup genera￾tion or energy storage to meet their power commitments to the grid. This backup could

include banks of batteries, heat stored in molten salt vats, and natural gas-powered steam

generators, but the optimum choices have not been resolved because of variables such as

plant power output and climate.

Digital 3D versus Rapid Prototyping

Recently introduced computer software makes it possible to design a product in a 3D for￾mat from concept sketch to shop documentation on a computer. This process, 3D digital

prototyping or modeling, can begin as an original design or be imported from another

source. The software permits a 3D image to be disassembled and its dimensions, materi￾als, and form changed before being reassembled as a new or modified product design on

the same screen. The designer can work cooperatively with other specialists to merge

valuable contributions for the achievement of the most cost-effective design. Changes

can easily be made before the design is released for manufacture.

xii

Virtual simulation software permits the 3D digital prototype to be given one or more

virtual stress tests with the results appearing graphically in color on the computer screen.

These simulations can include both mechanical and physical stress, and their results cor￾relate so closely with actual laboratory tests results that, in many cases, these tests can be

omitted. This saves time and the expense of ordering physical prototypes and can accel￾erate the whole design process and reduce time-to-market

There are, however, many reasons why physical models are desired. These include the

advantages of having a solid model for “hands on” inspection, giving all persons with

responsibilities for its design and marketing an opportunity to evaluate it. However, some

products require mandatory laboratory testing of a physical model to determine its com￾pliance with industry and consumer safety standards. Rapid prototyping has gained more

acceptance as the cost of building prototypes has declined.

Solid prototypes can be made from wax, photopolymers, and even powdered metals,

but those built for laboratory testing or as replacement parts can now be made from pow￾dered metal fused by lasers. After furnace firing they gain the strength to match that of

machined or cast parts. Rapid prototyping depends on dimensional data derived from a

CAD drawing for the preparation of software that directs all additive and subtractive rapid

prototyping machines.

The Origins of This Book

Many of the figures and illustrations in the archival Chapters 4 through 16 originally

appeared in foreign and domestic engineering magazines, some 50 or more years ago.

They were originally collected and republished in three McGraw-Hill reference books

dating back to the 1950s and 1960s. The author/editor of those books, Douglas C.

Greenwood, was then an editor for McGraw-Hill’s Product Engineering magazine. The

late Nicholas Chironis, the author/editor of the first edition of this book, selected illus￾trations and text from these books that he believed were worthy of preservation. He saw

them as a collection of successful design concepts that could be recycled for use in new

and modified products and would be a resource for engineers, designers, and students.

New illustrations and text were added in the subsequent four editions of this book.

The older content has been reorganized, redrawn as necessary, and in some cases deleted.

All original captions have been edited for improved readability and uniformity of style.

All illustrations are dimensionless because they are scalable to suit the intended applica￾tion. References to manufacturers and publications that no longer exist were deleted but,

where available, the names of inventors were retained for readers wishing to research the

status of the inventors’ patents. All government and academic laboratories and manufac￾turers mentioned in this edition have Internet Web sites that can be explored for further

information on specific subjects.

About the Illustrations

With the exception of illustrations obtained from earlier publications and those contributed

by laboratories or manufacturers, the figures in this book were drawn by the author on a

desktop computer. The sources for these figures include books, magazines, and Internet

Web sites. The author believes that clear 3D line or wireframe drawings with callouts com￾municate engineering information more rapidly and efficiently than photographs, which

often contain extraneous or unclear details.

Acknowledgments

I wish to thank the following companies and organizations for granting me permission to

use selected copyrighted illustrations and providing other valuable technical information

by various means, all useful in the preparation of this edition:

• ABB Robotics, Auburn Hills, Michigan

• Sandia National Laboratories, Sandia Corporation, Albuquerque, New Mexico

• SpaceClaim Corporation, Concord, Massachusetts

—Neil Sclater

xiii

ABOUT THE EDITOR

Neil Sclater began his career as a microwave engineer in the defense industry and as a

project engineer at a Boston consulting engineering firm before changing his career path

to writing and editing. He was an editor for Electronic Design magazine and later

McGraw-Hill’s Product Engineering magazine before starting his own technical com￾munications firm.

He served clients by writing and editing marketing studies, technical articles, and

new product releases. His clients included manufacturers of light-emitting diodes,

motors, switching-regulated power supplies, and lithium batteries. During this 30-year

period he contributed many bylined technical articles to various engineering publica￾tions on subjects ranging from semiconductor devices and servomechanisms to indus￾trial instrumentation.

Mr. Sclater holds degrees from Brown and Northeastern Universities. He is the

author or coauthor of 12 books including 11 engineering reference books published by

McGraw-Hill’s Professional Book Group. The subjects of these books include

microwave semiconductor devices, electronics technology, an electronics dictionary,

electrical power and lighting, and mechanical subjects. After the death of Nicholas P.

Chironis, the first author/editor of Mechanisms and Mechanical Devices Sourcebook,

Mr. Sclater became the author/editor of the four subsequent editions.