GEARS AND GEAR RATIOS
Gears
are actually just
wheels
with teeth on them.
The teeth allow the wheels to mesh together and
turn each other. In other words, they allow
forces to
be transmitted
from one wheel to another.
The mechanical advantage of a gear is evident when a
large gear meshes with a small gear. One full turn of the large
gear will produce, say, three full turns of the small gear.
Because of this, the smaller gear always turns faster than the
larger. On the other hand, the larger gear turns with greater
force than the smaller one. So, in this way, gears can be used
to make slow turning motion into rapid turning motion, or to
covert small forces into large forces. Multiple gears meshing
with each other are called
gear trains,
or
transmissions.
Your claw machine has a gear train
controlling the left-right motion of the
arm. The gear connected to the crank (or
any input force) is called the
driver gear.
The gear that is turned by the driver gear
is called the
driven gear.
Gears of
different sizes are used to increase or
decrease the speed or the force of rotary
motion, called
torque.
The relationship
between the number of teeth on meshing
gears is called the
gear ratio.
The gear
ratio indicates the change in speed or
torque from one gear to the other.
The
levers connected to the tops of the
hydraulic cylinders help you transfer the force
from your hand to move the pistons inside the
cylinders. Levers are rigid bars that pivot on a
point called the
fulcrum. A weight (or load) at
one point on the bar can be moved by applying
a
force (the effort) to another point on the bar.
If the distance from the fulcrum to the effort
(the effort arm) is greater than the distance
from the fulcrum to the load
(the load arm),
then a smaller force can move a larger load.
This is how the lever makes work easier.
leve
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CHECK IT OUT
40 teeth
Driver gear
20 teeth
Driven gear
Number teeth driven gear
Velocity
ratio = Number teeth driver gear
(1:2)
=
=
20
40
1
2