DT Flashcards
what are the 4 types of movemet/direction
linear
rotary motion
reciprocating motion
oscillating motion
linear
moves in a straight line
rotary motion
moves around a central axis
reciprocating motion
moves back and forth or up and down in a straight like
oscillating motion
moves back and forth along a curved line
input
the force put it
process
what the force causes (mechanism)
output
result of input
what are the 3 types of levers
load
effort
fulcrum
examples of 1st class levers
see-saw , scissors
examples of 2nd class levers
wheelbarrow , stapler
examples of 3rd class levers
broom , tweezers
what are linkages
a collection of levers joined together
what is a reverse motion linkage
changes the direction of the motion
what are cams
shaped pieces of metal or plastic fixed to a rotating shaft
what are the 3 parts of cam mechanisms
cam slide follower
what does a cam do
rotates continually
what does a follower do
moves up and down (rise and fall , dwell
what does a slide do
prevents follower from moving side to side
different shaped cams…
cause different outputs
round and shaft center cam=
dwell
different shape and shaft not central-
rise or fall
what are gear trains
a number of gears connected together
what are gears
toothed wheels connected to shafts
how do gears work
the teeth interlock and the driver shaft rotates
what are spur gears
both rotate in the opposite direction
which gear always rotates faster
the small gear
what is the difference between the 2 speeds called
velocity
what is the gear ratio
gear ratio= number of teeth on driven gear/number of teeth on the driver gear
e.g 60/15=4
what do pulleys do
change the direction/speed/torque/turning force
what is a pulley system
2 pulleys on a shaft connected by a bekth
how do pulleys help
make changing direction of the force easier
torque meaning
how much a force is acting on an object that makes it rotate
what is the difference of pulley speeds called
the velocity ratio
