MECHANISMS
Cable Control
can control from a distance
can go around obstacles
works well in tension
Applications
opening/closing stage curtains
bicycle brakes
cable car mechanism
Hydraulic Control
using liquid under pressure
can control some distance away
quiet operation
leakage can result in loss of control
Applications
car brakes
control aeroplane wing flaps
Pneumatic Control
using pressurised air
noisy operation
air is compressible,limited loading
leakage result in loss of control
require little maintenance
Applications
safety harness
dentist drill
production lines
Mechanical Systems
input,process,output
Open Loop
No feedback
step bin
Closed Loop
Has feedback
toilet cistern
Types of Mechanism
Rack and Pinion
lowering of chuck for bench drill
focusing mechanism
car steering mechanism
camera tripod
Cranks
piston engine
crank-and-slider
bicycle pedal
handle
Gears
Worm Gear
gear boxes
venetian blinds
Bevel
food mixers
hand drill
gear boxes
Gear Train
Idler Gear
Gear Ratio
Spur
Ratchet and Pawl
ratchet screwdrivers
fishing reels
winches
clocks
socket spanners
Cams
Application
automata
locking devices
washing machines
engines
follower
eccentric
pear
snail
Springs
tension
resist stretching force
foldup chairs/cinema seats
trampolines
compression
resist compressive force
car suspensions
retractable pens
battery holders
torsion
resist turning force
foot pumps
clothes peg
bulldog clips
swinging doors
flat
return to original shape when bent
staplers
spring clips
Screws
convert rotary to linear
glue sticks
taps
lipsticks
adjustable spanners
Pulleys
Application
raising/lowering of lifeboats
washing machine
gantry crane
drilling machines
Velocity Ratio
Crossed Drive
opposite direction
Open Drive
same direction
Driver/driven
Simple Pulley
Compound Pulley
Linkages
Four-bar Linkage
pop-up books
windscreen wipers
Toolbox
Scissors platform
Levers
1st class
scissors
2nd class
nutcracker
3rd class
ice tongs
Mechanical Advantage
output force/input force
more than 1
brakes
<1
ice tongs
Functions of Mechanism
Conversion
change type of movement
glue stick
Transmission
change place of movement
bathroom sink
Control
speed
clock mechanism
direction
hand drill
distance
pantograph
amount of force
screwjack
Types of Movement
CIrcular/Rotary
in circle
rotating wheel
Oscillating
forwards & backwards in arc of circle
pendulum
Linear
straight line
car moving on a straight road
Reciprocating
forwards & backwards in a straight line
needle of sewing machine