Mechanisms Flashcards
gear ratio
relationship between teeth on 2 gears
rotary motion
turning around in a circle
linear motion
moving in a straight line
recipricatory
linear motion in 2 directions (moves back an forth on a given track)
oscillatory
swinging from side to side along an arc
mass
amount of material in an object
weight
measure of gravity pull on an object
gravity
force of attraction between all objects of matter
weight equation
weight = mass x acceleration due to gravity
work
work is done when a force causes an object to move (mount of mechanical energy transferred by force to an object)
watt
unit of measurement for power
calculate watt
1 watt = 1J/S
Lever
rigid bar pivots around a fulcrum used to carry a load
what does a lever do
magnifies/ increases movement( small effort/ large distance)
class 1 lever
load - fulcrum - effort
class 2 lever
effort - load - fulcrum
class 3 lever
load - effort - fulcrum
mechanical advantage
how a mechanism helps eg - lifts a heavier load than you would be able to
moment of force
product of force and perp dist between line of action and fulcrum
material testing - why?
-quality control
-standardisation of components
-values for properties eg strength
-success of heat treatments can be measured
vickers hardness test
-square based pyramid pushed into material,
- diagonal length of indent is measured
- converted to Vickers hardness scale
brinnell hardness test
-spere is pushed into material
-diameter of crevice created is measured
rockwell hardness test
- cone pushed into material
- measurement taken from dial on machine
izod impact test
notch on specimen from pendulum
-specimen held vertically in vice and struck with pendulum
-striking force 167 J
charpy impact test
specimen held horizontally in vice
-notch on opposite side to pendulum strike
-striking force 300J
tensile testing
how much it stretches before it snaps
hardness tests?
Vickers, Brinell, Rockwell
Impact tests
Charpy, Izod
additive manufacturing
cartoon of 3d products layer by layer
subtractive manufacturig
manufacturing by removing material
linkages
used to change direction or type of motion, or size of force in a mechanism (diagrams)
springs
pushes or pulls objects together - tension and compression springs
belt an pulley system
rope belt runs around two wheels
RPM
revolutions per minute
fixed pulley
one fixed wheel and one rope used to lift objects
movable pulley
free axle - free to move up and down in space
compound pulley systems
combination of moveable and fixed pulleys to increase mechanical advantage
