اسم المؤلف
Alan Hendrickson
التاريخ
31 يناير 2021
المشاهدات
338
التقييم
(لا توجد تقييمات)

Mechanical Design for the Stage
Alan Hendrickson
Colin Buckhurst
Preface xiii
Part I: The Physics of Stage Machinery . 1
1 Basic Concepts & Definitions 3
Fundamentals 3
Displacement 4
Definition of Translational Displacement . 5
Speed and Velocity 7
Acceleration . 9
Graphical Relationships Between x, v, and a 9
Problems 12
2 The Equations of Constant Acceleration 13
Constant Acceleration 13
Equations of Constant Acceleration . 14
Moves with a Given Time and Distance 18
The Acceleration Due to Gravity 20
Problems 22
3 The Force to Accelerate Mass: Facceleration . 23
Overview 23
Newton’s Laws of Motion 23
Mass and Force 24
Conversion Table – Mass and Force . 25
Weight 26
The Force Needed to Accelerate Mass 27
Problems 28vi Contents
4 The Friction Force, Ffriction 29
Friction—Complex and Simplified . 29
Definitions . 30
Sliding Friction . 32
Static Friction 33
Kinetic Friction . 35
Measuring Coefficients of Friction . 36
Rolling Friction . 38
Friction of Ropes on Cylinders 40
Problems . 43
5 The Lifting Force, Flifting . 45
Gravity, Weight, and the Lifting Force 45
The Lifting Force . 45
Counterweighting . 46
Problems . 48
6 Maximum Power and Force 49
Power 49
Maximum Power . 51
Maximum Force . 55
Problems . 57
7 Basic Concepts of Rotational Motion . 59
Definition of Rotational Motion 59
Coordinate Systems 59
Angular Displacement . 60
Angular Speed 62
Angular Acceleration . 63
Converting Between Linear and Rotational . 63
An Aside: Centripetal Acceleration . 64
The Equations of Constant Angular Acceleration . 65
Torque 66
Problems . 68
8 The Torque to Accelerate Mass, Taccel . 71
Overview . 71
Moment of Inertia . 72
Transferring the Axis of Rotation 75
An Aside: WK2 . 77
The Torque to Accelerate Mass 78Contents vii
Rolling Objects 84
Problems 86
9 The Torque to Overcome Friction, Tfriction . 87
Rotation and Friction 87
The Torque Due to Friction, Tfriction . 88
Caster Friction and Turntables . 89
Rotational Bearing Friction 95
Problems . 100
10 The Lifting Torque, Tlift . 103
Overview . 103
The Center of Mass . 104
The Lifting Torque 106
Problems . 110
11 Maximum Power and Torque . 113
Power 113
Maximum Power 115
Maximum Torque 124
An Important Caveat—Mass and Spring Vibrations . 126
Problems . 127
12 Combining Multiple Motions . 129
Overview . 129
Combining Linear and Rotational Power . 129
Converting Terms within the Power Formula . 133
Combining Multiple Speed Effects 136
Problems . 141
Part II: Stage Machinery Components 143
13 Safety 145
General Concepts 145
Risk Assessment 146
Hazard Abatement 146
Single Failure Proof Design . 147
Design Factor and Factor of Safety 148
Emergency Stop 150
Codes and Standards . 150
Formalized Procedures 152viii Contents
Inspection and Maintenance 153
14 Actuators . 155
Electric, Hydraulic or Pneumatic . 155
Powering the Actuator 155
Electric Motors 155
Common Motor Types 156
Sizes and Configurations . 157
The Speed/Torque Curve . 159
Enclosures 160
Service Factor . 160
Choosing an Electric Motor 160
Hydraulic Actuators . 161
Pneumatic Actuators . 161
Cylinders 162
Stop Tube 165
Cylinder Selection . 166
Counterbalance Valves 167
15 Speed Reduction . 169
Speed Reduction 169
Speed Reduction Methods . 171
Gear Reducers . 173
Terms Used in Gear Reducer Selection . 174
Using the Reducer Ratings . 178
Gear Motor Selection 180
Roller Chain . 181
Roller Chain Strength 182
Roller Chain Sprockets 184
Roller Chain Guidelines 185
V-belts and Sheaves . 185
Toothed Belts . 186
16 Shafting . 187
Shaft Basics . 187
Shaft Strength . 187
Shaft Diameter and Torsional Stiffness Rule of Thumb 189
Other Shaft Stress Sources . 190
Combined Torque and Bending Shaft Analysis 191
Resonant Speed 193Contents ix
Stress Concentrations . 193
Keys and Keyways 194
Practical Shaft Design Considerations 195
Jaw Couplings . 196
Roller Chain Couplings 197
Universal Joints 197
Types of Bushings 199
17 Bearings and Wheels 201
Bearings . 201
Rolling Element Bearings . 202
Plain Bearings . 203
Calculating Pressure and Velocity . 204
Mounted Bearings 205
Linear Bearings . 207
Slewing Rings, or Turntable Bearings 208
Cam Followers . 209
Track Capacity . 210
Bearing Selection Considerations . 211
Wheels and Casters . 212
Wheel and Caster Terminology 212
Specialty Wheels 213
18 Wire Rope and Sheaves . 215
Wire Rope 215
Wire Rope Terminology 215
Inspection 219
Sheave Terminology . 219
19 Cable Drums 223
Grooved Cable Drums 223
Drum Types 223
Drum Sections . 224
Drum Materials . 226
Groove Dimensions . 226
Drum Diameter . 227
Drum Width 227
Drum Groove Threads per Inch Values . 227
Cable Anchors . 229
Drum Construction . 229x Contents
Drum Reeving . 230
20 Screw Mechanisms 233
Screw Mechanism Basics . 233
Sliding Contact Screws: Acme Screws . 234
Rolling Contact Screws: Ball Screws 235
Common Screw Mechanism Uses . 236
21 Brakes 239
Spring-Set Brakes 239
Brake Noise . 240
Brake Placement 242
Manual Release 243
Orientation 244
Fluid Power Brake Circuits . 244
Overspeed Braking . 245
Brake Engage and Release Speed . 245
22 Control Components . 247
External Sensors 247
Position Sensing 248
Limit Box Ratios 250
Disconnects . 251
Connectors 252
23 Frames and Framing . 255
General Concepts 255
Open vs. Enclosed Frames . 255
Stock Shapes vs. CNC Plates 256
Steel vs. Aluminum . 258
Mounting and Handling Options . 258
Structural Design Considerations . 259
Part III: A Mechanical Design Process . 263
Overview 265
Five Key Points 266Contents xi
Influences on an Individual’s Design Abilities . 272
A Brief Overview of the Mechanical Design Process . 274
25 Developing a Design Specification . 279
Overview . 279
When a Written Specification Is Useful . 281
Elements of a Complete Specification 282
Summary . 296
26 Concept Design . 297
Overview . 297
Concept Generation Techniques . 298
Concept Evaluation . 304
An Evaluation Matrix . 305
Freedom and Constraint 306
Degrees of Freedom . 306
Some Diverse Constraint Issues . 309
27 Detail Design 311
Overview . 311
Analysis . 311
Failure Modes and Effects Analysis, FMEA 313
Parts and Materials List 315
Drafting . 315
28 Design for Manufacture . 317
Overview . 317
Design for Fabrication 318
Design for Fabrication Issues 318
Outside Part Fabrication 322
Design for Assembly . 325
Conclusion 330
Part IV: A Compendium of Stage Machinery . 331
29 A Compendium of Stage Machinery . 333
Overview . 333
Machine Details Common to Many Machines . 334
Backup Needs and Techniques 336xii Contents
30 Winches . 341
Overview 341
Typical Applications . 341
Cable Drum Winch Concepts 344
Chain Drive Winch Concepts 344
Direct Drive Winch Concepts 346
Zero Fleet Angle Winch Concepts 350
Machine Details 355
Winch Specification Issues . 355
31 Turntable Drives . 359
Overview 359
A Typical Application 360
Turntable Drive Concepts . 367
Limited Rotation Turntable Drive Concepts . 376
Machine Details 379
Turntable Drive Specification 381
32 Lifts . 385
Overview 385
A Typical Application 386
Lift Concepts . 393
Hydraulic Cylinder Run Lifts and Leveling Techniques 401
Lift Specification 404
33 Tracked Scenery . 407
Overview 407
Typical Applications . 408
Deck Track Drive Concepts 417
Electric Dogs . 420
Bibliography 423
Index .
427
Index
A
acceleration
angular 63
centripetal 64
constant 13
due to gravity 20
linear 9, 13
acme screw 234
B
backups 336
ball screws 235
bearing
friction 95
bearings 201–212
cam followers 209
linear 207
mounted 205
flange block 205
pillow block 205
self-aligning 206
plain 96, 203
PV factor 204
rolling element
friction 99
types 202
slewing rings 208
thrust 98
belts
toothed 186
V 185
brakes 239–246
caliper disk 239
drum 240
spring-set 239
bushings 199
keyless 200
QD 199
split taper 199
taper-lock 199
C
cable retainers 355
cam followers 209
stud 209
yoke 209
casters 212
triple-swivel 214
center distance 174
center of mass 104
concept design 297
concept evaluation 304
concept evaluation matrix 305
concept generation techniques 298
concept sketches 334
Cone Drive 172
configuration concepts 301, 334
convertion
angular to linear 63
linear to angular 63
coordinates
polar 59
coordinatesCartesian 59
counterbalance valve 167
counterweight 46
cross product 67
customary units 5, 24
cylinders 162
clevis mount 164
common sizes 164
farm duty 162
force 163
K distance 165
mounting configurations 164
rod size 164
selection 166
stop tube 165
tie rod 162428 Mechanical Design for the Stage
trunnion mount 164
welded end 162
D
D/d ratio 217
deck tracks 407–??
dogs 409
drive concepts 417
specifications 422
degrees of freedom 306
design factor 148
design for assembly 325
design for fabrication 318
design for manufacture 317
DFA 325
DFM 317
disconnect 247
disconnects 251
displacement 4, 5
angular 60
dot product 49
drawbridge 108
drums 223–231
cable anchors 229
diameter 227
groove dimensions 226
groove pitch 227
wall thickness 224
yo-yo 224
E
efficiency 169
emergency stop 150
Category 0 150
encoders 250
equations
constant acceleration 14–20
constant angular accel 65
ESTA 151
E-Stop 150
extrusions 325
F
factor
design 148
safety 148
failure modes and effects analysis 313
FMEA 313
force 24
acceleration 23–28
friction 29–43
lifting 45–48
maximum 55
normal 30
frames 255–261
corner details 257
dolly 258
water jet cut 256
freedom and constraint 306
friction
bearing 95
coefficients 34
rolling 40
kinetic 35
measuring 36
rolling 38
rope on cylinders 40
sliding 32–38
static 33
fundamentals 3, 24
G
gear reducers 173
backdriving 177
mechanical horsepower 176
parallel shaft 173
service factor 178
thermal horsepower 176
worm 173
efficiency 177
gearmotors 158
selection 180
gears 171–180
bevel 172
helical 172
miter 172
rack and pinion 172
spur 171
worm 172
center distance 174
Gravity 20
grommet drive 42
guarding 151
guards 147
H
hand cranks 338
hazards 146
abatement 146
horsepower 49
hydraulic
actuators 161
I
inspection
scheduled 153
intensifier 244Index 429
International Electrotechnical
Commission 158
J
jerk 9
K
K distance 165
keys and keyways 194
L
liability 145, 269
lifts 385–??
concepts 393
scissor lifts 394
specification 404
wire rope run 386
limit boxes 247
locked rotor torque 159
Loctite 328
M
maintenance 153
Mass 23
mass 24
mechanical design
five key points 266
individual’s abilities 272
teams 269, 270
mechanical design process
concept design 297–310
detail design 311–316
manufacture 317–330
overview 274
specification 279–296
elements 282
moment of inertia 72
basic shapes 73
reflected 138
ratio 140
transfer axis 75
motors
electric 155
AC 156
C-face 158
DC 156
IEC 158
NEMA 157
servo 157
speed torque curve 159
N
National Electrical Manufacturer’s
Association 157
National Fire Protection Association 150
Newton’s Laws 23
NFPA
Article 79 150, 251
normal force 30
nylocks 328
O
Osborn’s checklist 302
oscillation reduction 127
OSHA 151, 152
P
plane of contact 30
pneumatic
actuators 161
polar section modulus 187
position sensing 248
power 49–55
combined linear angular 129
maximum angular 115
rotation 113–123
Pugh, Stuart 282
pull pin release 337
R
reduction ratio 170
reduction stage 171
reflected moment of inertia 138
risk assessment 146
roller chain 181–185
ANSI standard numbering 182
offset 181
pitch 182
sprockets 184
A type 184
B type 185
chordal action 184
wrench clearance 329
strength 182
tensioners 336
rolling objects 84
Roteks 208
rules of thumb 284
S
safety 145–154, 292430 Mechanical Design for the Stage
safety factor 148
scissor lifts 394
screw mechanisms 233–238
acme 234
ball 235
screw jacks 236
service factor
motor 160
shaft collars 335
shaft couplings 196
jaw type 196
roller chain 197
universal joints 197
shafts 187–196
combined torque and bending 191
hollow shaft factor 191
keys 194
derating 188
recommended diameters 196
strength 187
stress concentrations 193
torsional stiffness 189
sheaves 219
SI 5
single failure proof design 147
slewing rings 208
slip rings 379
snap rings 335
specification 282
speed
angular 62
linear 7
multiple in one system 136
reduction 169
springiness 126
stop tube 165
subscripts 5
T
tapped holes 321
TEAO 160
TEFC 160
TENV 160
Toothed belts 186
toothed belts 186
torque 66–68
accereration 71–85
friction 87–100
lifting 103–110
maximum 124
triple-swivel casters 214
turntable bearings 208
turntable drive 42
turntable drives 359–384
concepts 367
grommet 360
position feedback drives 367
turntables
caster friction 89
U
universal joints 197
V
V-belts 185, 186
vector 4
angular speed 113
torque 113
velocity
linear 7
W
watts 50
weight 26, 45
weld nuts 322
wheels 212
winches 341–358
concepts 341, 344
deck 341
cable tensioner 238
specification 355
zero fleet angle 350
wire rope 215
7 × 19 215
D/d ratio 217
galvanized aircraft cable 216
wrench clearance 326
X
XP 160
كلمة سر فك الضغط : books-world.net