Mechanisms and Mechanical Devices Sourcebook, 5th Edition

561 Pages·2011·28.404 MB·English

by  Neil Sclater

MECHANISMS AND
MECHANICAL DEVICES
SOURCEBOOK
Fifth Edition
NEIL SCLATER
McGraw-Hill
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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
iii
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