Elenco Tumbling Robot - Manual (Page 9)

Various Linkage
MECHANISM OF MACHINES MASTER CLASS
CRANK
-TRANSFER ROTATIONAL MOTION TO LINEAR MOTION-
A crank is a system that change
a rotational motion into a linear
sliding motion. It is widely used
in many equipments just like
gears and belts.
•Basic structure of a crank
A crank has a circular disk called crank and a straight
rod attached at an off center location of the disk. As
crank rotates, the end of the rod slides linearly.
Crank
Front Windshield
Wiper blade
Axis of a motor
rod
• Crank of a Car Engine
A gasoline explosion in a
cylinder pushes down the
piston. This motion of the
piston is transferred by
connecting rod to the crank
and to the flywheel
(attached at the end of the
crankshaft, but omitted from
the illustration). The
flywheel keeps the
momentum of the rotation.
The crank keeps rotating
and pushes the piston back
up. The piston moves up
and down and the crank
shifts that motion into
rotational motion.
•Windshield Wiper
Windshield wiper of a car
uses a crank to change
rotational power of a motor
to sliding motion so that
the wiper blades move side
to side on a windshield.
There are various linkage technics to power one part
of the system and move other parts in different
patterns. There are many more technics other than
the examples of windshield wipers and car engines.
Combining a crank
and a slider, a
rotational motion
can be changed
into linear sliding
motion or vice
versa. Joining four bars and
form a loop, one side
to side motion can be
changed to another
side to side motion.
Combining a
crank and a four
bar linkage, a
rotational
motion can be
changed into a
side to side
fanning motion
or vice versa.
Crank Slider Mechanism
Four Bar Linkage with Crank
Four Bar Linkage
CRANK
Worm
Piston
Cylinder
Connecting rod
Crank
Crankshaft
Crank Connecting Rod
16 17
JR. SCIENTIS
T
TUMBLING ROBO
T