Page 602 - Ultimate Visual Dictionary (DK)

THE MODERN WORLD
Drills

THE ELECTRICALLY POWERED MOTOR OF A POWER DRILL, cooled by a fan, turns a
shaft at high speed. The shaft connects, in turn, to a system of gears that rotates
MOTOR ASSEMBLY
a chuck even faster. Clamped by the chuck, a sharp bit cuts out the hole, and
at the same time the bit’s screw-shaped grooves channel the waste out of Armature
Armature spindle
the hole. For drilling hard materials, many power drills have Commutator
a hammer mechanism; when this is operated a ratchet in Fan
the gearcase causes the chuck and bit to pound in and
out as they drill. A hand drill, although slower and
less forceful than a power drill, is easier to control.
For cutting wide holes, carpenters often prefer a
Motor
brace-and-bit. This acts like a lever: the bowed
case
handle of the brace moves a larger Motor case
distance than the bit, turning the bit Field coils
with extra force.

Spring

Screw
Brush Washer
Lead wire

Top insert Hammer mechanism
blank
actuator
Brush holder Screw hole
Electromagnetic
induction
capacitor

Triac
device
Chuck key Hammer
holder actuator
position
Gearcase
position
Screw INTERNAL VIEW OF CLAMSHELL Motor
position
Lock
button

Trigger On/off trigger
position

TRIGGER MECHANISM
Washer
Cable Spring

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