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

PREFACE XI

CHAPTER 1 BASICS OF MECHANISMS Introduction Physical Principles

Efficiency of Machines Mechanical Advantage Velocity Ratio

Inclined Plane Pulley Systems Screw-Type Jack Levers and Mechanisms

Levers Winches, Windlasses, and Capstans

Linkages Simple Planar Linkages Specialized Linkages Straight-Line Generators Rotary/Linear Linkages

Specialized Mechanisms Gears and Gearing

Simple Gear Trains Compound Gear Trains Gear Classification Practical Gear Configurations Gear Tooth Geometry Gear Terminology Gear Dynamics Terminology

Pulleys and Belts Sprockets and Chains Cam Mechanisms

Classification of Cam Mechanisms Cam Terminology

Clutch Mechanisms Externally Controlled Friction Clutches Externally Controlled Positive Clutches Internally Controlled Clutches

Glossary of Common Mechanical Terms

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CHAPTER 2 MOTION CONTROL SYSTEMS 21 Motion Control Systems Overview Glossary of Motion Control Terms Mechanical Components Form Specialized Motion-Control Systems Servomotors, Stepper Motors, and Actuators for Motion Control Servosystem Feedback Sensors Solenoids and Their Applications

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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

Harnessing Moving-Water Power Tidal Electric Power Generation Ocean-Wave Power Generation Another Possible Mechanical Hydropower Solution The Relative Costs of Renewable Energy

Glossary of Wind Turbine Terms Renewable Energy Resources

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CHAPTER 5 LINKAGES: DRIVES AND MECHANISMS

Four-Bar Linkages and Typical Industrial Applications Seven Linkages for Transport Mechanisms Five Linkages for Straight-Line Motion Six Expanding and Contracting Linkages Four Linkages for Different Motions Nine Linkages for Accelerating and Decelerating Linear Motions Twelve Linkages for Multiplying Short Motions Four Parallel-Link Mechanisms Seven Stroke Multiplier Linkages Nine Force and Stroke Multiplier Linkages Eighteen Variations of Differential Linkage Four-Bar Space Mechanisms Seven Three-Dimensional Linkage Drives Thirteen Different Toggle Linkage Applications Hinged Links and Torsion Bushings Soft-Start Drives Eight Linkages for Band Clutches and Brakes Design of Crank-and-Rocker Links for Optimum Force Transmission Design of Four-Bar Linkages for Angular Motion Multibar Linkages for Curvilinear Motions Roberts' Law Helps to Design Alternate Four-Bar Linkages Design of Slider-Crank Mechanisms

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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

CHAPTER 7 CAM, GENEVA, AND RATCHET DRIVES AND MECHANISMS

Cam-Controlled Planetary Gear System Five Cam-Stroke-Amplifying Mechanisms Cam-Curve-Generating Mechanisms Fifteen Different Cam Mechanisms Ten Special-Function Cams Twenty Geneva Drives Six Modified Geneva Drives Kinematics of External Geneva Wheels Kinematics of Internal Geneva Wheels Star Wheels Challenge Geneva Drives for Indexing Ratchet-Tooth Speed-Change Drive Modified Ratchet Drive Eight Toothless Ratchets Analysis of Ratchet Wheels

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CHAPTER 8 CLUTCHES AND BRAKES Twelve Clutches with External or Internal Control Spring-Wrapped Clutch Slips at Preset Torque Controlled-Slip Expands Spring Clutch Applications Spring Bands Improve Overrunning Clutch Slip and Bidirectional Clutches Combine to Control Torque Slip Clutches Serve Many Design Functions Walking Pressure Plate Delivers Constant Torque Seven Overrunning Clutches One-Way Clutch Has Spring-Loaded Pins and Sprags Roller Clutch Provides Two Output Speeds Seven Overriding Clutches Ten Applications for Overrunning Clutches Eight Sprag Clutch Applications Six Small Clutches Perform Precise Tasks Twelve Different Station Clutches Twelve Applications for Electromagnetic Clutches and Brakes

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CHAPTER 9 LATCHING, FASTENING, AND CLAMPING DEVICES AND MECHANISMS

Sixteen Latch, Toggle, and Trigger Devices Fourteen Snap-Action Devices Remote Controlled Latch Toggle Fastener Inserts, Locks, and Releases Easily Grapple Frees Loads Automatically Quick-Release Lock Pin Has a Ball Detent Automatic Brake Locks Hoist When Driving Torque Ceases Lift-Tong Mechanism Firmly Grips Objects Perpendicular-Force Latch Two Quick-Release Mechanisms Shape-Memory Alloy Devices Release Latches Ring Springs Clamp Platform Elevator into Position Cammed Jaws in Hydraulic Cylinder Grip Sheet Metal Quick-Acting Clamps for Machines and Fixtures Nine Friction Clamping Devices Detents for Stopping Mechanical Movements Twelve Clamping Methods for Aligning Adjustable Parts Spring-Loaded Chucks and Holding Fixtures

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CHAPTER 10 CHAIN AND BELT DEVICES AND MECHANISMS 261

Twelve Variable-Speed Belt and Chain Drives Belts and Chains Are Available in Many Different Forms Change Center Distance without Altering Speed Ratio Motor Mount Pivots to Control Belt Tension Ten Roller Chains and Their Adaptations Twelve Applications for Roller Chain Six Mechanisms for Reducing Pulsations in Chain Drives

Flat Springs in Mechanisms Twelve Ways to Use Metal Springs Seven Overriding Spring Mechanisms for Low-Torque Drives Six Spring Motors and Associated Mechanisms Twelve Air Spring Applications Novel Applications for Different Springs Applications for Belleville Springs Vibration Control with Spring Linkage Twenty Screw Devices Ten Applications for Screw Mechanisms Seven Special Screw Arrangements Fourteen Spring and Screw Adjusting Devices A Long-Stroke, High-Resolution Linear Actuator

CHAPTER 12 SHAFT COUPLINGS AND CONNECTIONS Four Couplings for Parallel Shafts Links and Disks Couple Offset Shafts Disk-and-Link Couplings Simplify Torque Transmission Interlocking Space-Frames Flex as They Transmit Shaft Torque Coupling with Off-Center Pins Connects Misaligned Shafts Universal Joint Transmits Torque 45° at Constant Speed Ten Universal Shaft Couplings Nineteen Methods for Coupling Rotating Shafts Five Different Pin-and-Link Couplings Ten Different Splined Connections Fourteen Ways to Fasten Hubs to Shafts Polygon Shapes Provide Superior Connections

CHAPTER 13 MOTION-SPECIFIC DEVICES, MECHANISMS, AND MACHINES Timing Belts, Four-Bar Linkage Team Up for Smooth Indexing Ten Indexing and Intermittent Mechanisms Twenty-Seven Rotary-to-Reciprocating Motion and Dwell Mechanisms Five Friction Mechanisms for Intermittent Rotary Motion Nine Different Ball Slides for Linear Motion Bail-Bearing Screws Convert Rotary to Linear Motion Nineteen Arrangements for Changing Linear Motion Eight Adjustable-Output Mechanisms Four Different Reversing Mechanisms Ten Mechanical Computing Mechanisms Nine Different Mechanical Power Amplifiers Forty-Three Variable-Speed Drives and Transmissions Ten Variable-Speed Friction Drives Four Drives Convert Oscillating Motion to One-Way Rotation Eighteen Different Liquid and Vacuum Pumps

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CHAPTER 11 SPRING AND SCREW DEVICES AND MECHANISMS 279

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CHAPTER 14

CHAPTER 15

CHAPTER 16

Ten Different Pump Designs Explained Glossary of Pump Terms Bearingless Motor-Generators Have Higher Speed and Longer Life Energy Exchange in Seawater Desalination Boosts Efficiency Two-Cycle Engine Improves Efficiency and Performance

PACKAGING, CONVEYING, HANDLING, AND SAFETY MECHANISMS AND MACHINES Fifteen Devices That Sort, Feed, or Weigh Seven Cutting Mechanisms Two Flipping Mechanisms One Vibrating Mechanism Seven Basic Parts Selectors Eleven Parts-Handling Mechanisms Seven Automatic-Feed Mechanisms Fifteen Conveyor Systems for Production Machines Seven Traversing Mechanisms for Winding Machines Vacuum Pickup for Positioning Pills Machine Applies Labels from Stacks or Rollers Twenty High-Speed Machines for Applying Adhesives Twenty-Four Automatic Mechanisms for Stopping Unsafe Machines Six Automatic Electrical Circuits for Stopping Textile Machines Six Automatic Mechanisms for Assuring Safe Machine Operation

TORQUE, SPEED, TENSION, AND LIMIT CONTROL SYSTEMS

Applications of the Differential Winch to Control Systems Six Ways to Prevent Reverse Rotation Caliper Brakes Keep Paper Tension in Web Presses Control System for Paper Cutting Warning System Prevents Overloading of Boom Lever System Monitors Cable Tension Eight Torque-Limiters Protect Light-Duty Drives Thirteen Limiters Prevent Overloading Seven Ways to Limit Shaft Rotation Mechanical Systems for Controlling Tension and Speed Nine Drives for Controlling Tension Limit Switches in Machinery Nine Automatic Speed Governors Eight Speed Control Devices for Mechanisms Cable-Braking System Limits Descent Rate

INSTRUMENTS AND CONTROLS: PNEUMATIC, HYDRAULIC, ELECTRIC, AND ELECTRONIC

Twenty-Four Mechanisms Actuated by Pneumatic or Hydraulic Cylinders Foot-Controlled Braking System Fifteen Tasks for Pneumatic Power Ten Applications for Metal Diaphragms and Capsules Nine Differential Transformer Sensors High-Speed Electronic Counters Applications for Permanent Magnets Nine Electrically Driven Hammers Sixteen Thermostatic Instruments and Controls Eight Temperature-Regulating Controls Seven Photoelectric Controls

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VIII

Liquid Level Indicators and Controllers Applications for Explosive-Cartridge Devices Centrifugal, Pneumatic, Hydraulic, and Electric Governors

CHAPTER 17 3D DIGITAL PROTOTYPES AND SIMULATION

Introduction to 3D Digital Prototypes and Simulation A Short History of Engineering Drawing Transition from Board to Screen CAD Product Features 3D Digital Prototypes vs. Rapid Prototyping The Ongoing Role of 2D Drawings Functions of Tools in 3D Digital Prototype Software File Types for 3D Digital Prototypes Computer-Aided Engineering (CAE) Simulation Software Simulated Stress Analysis

Glossary of Computer-Aided Design Terms

CHAPTER 18 RAPID PROTOTYPING

Rapid Prototyping Focuses on Building Functional Parts Rapid Prototyping Steps Commercial Rapid Prototyping Choices Commercial Additive RP Processes Subtractive and R&D Laboratory Processes

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CHAPTER 19 NEW DIRECTIONS IN MECHANICAL ENGINEERING The Role of Microtechnology in Mechanical Engineering Micromachines Open a New Frontier for Machine Design Multilevel Fabrication Permits More Complex and Functional MEMS Electron Microscopes: Key Tools in Micro- and Nanotechnology Gallery of MEMS Electron-Microscope Images MEMS Actuators—Thermal and Electrostatic MEMS Chips Become Integrated Microcontrol Systems Alternative Materials for Building MEMS LIGA: An Alternative Method for Making Microminiature Parts The Role of Nanotechnology in Science and Engineering Carbon: An Engineering Material with a Future Nanoactuators Based on Electrostatic Forces on Dielectrics The Lunar Electric Rover: A New Concept for Moon Travel

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