hydrodynamic torque converter, hydrostatic, or an
electric generator type.
POWER TRAIN All moving parts connecting an
engine with the point or points where work is
PRIME MOVER A tractor or other vehicle used to
pull other machines.
PROPELLER SHAFT Usually a main drive shaft
fitted with universal joints.
PSI or psi Pressure in pounds per square inch.
PUMP, DIAPHRAGM A pump that moves water by
the reciprocating motion of a diaphragm in a
chamber having inlet and outlet check valves.
PUSHER A tractor that pushes a scraper to help it pick
up a load.
RAKE BLADE A dozer blade or attachment made of
RAKE, ROCK A heavy-duty rake blade.
RANGE POLE A pole marked in alternate red and
white bonds, 1 foot high.
RED TOPS Grade stakes with red tops to indicate
finish subgrade level, usually a 2-inch by 2-inch by
6-inch hub stake.
REFUSAL The depth beyond which a pile cannot be
RIPRAP Heavy stones placed at the edge of the water
to protect the soil from waves or current.
RIPPER A towed machine, equipped with teeth, used
primarily for loosening hard soil and soft rock.
ROAD OIL A heavy petroleum oil, usually one of the
slow-curing (sc) grades.
ROCK The hard, firm, and stable parts of earths crust.
ROTARY TILLER A machine that loosens and mixes
soil and vegetation by means of a high-speed rotor
equipped with tines.
RPM or rpm Revolutions per minute.
RUBBLE DRAINS French drains.
RULE OF THUMB A statement or formula that is not
exactly correct but is accurate enough for use in
SAND A loose soil, composed of particles between
1/16 mm and 2 mm in diameter.
SCRAPER (Carrying scraper) (Pan) A digging,
hauling, and grading machine, having a cutting
edge, a carrying bowl, a movable front wall (apron),
and a dumping or ejecting mechanism.
SCREEN (1) A mesh or bar surface, used for
separating pieces or particles of different sizes. (2)
SEIZE To bind wire rope with soft wire to prevent it
from raveling when it is cut.
SEMITRAILER A towed vehicle whose front rests on
the towing unit.
SHEEPSFOOT A tamping roller with feet expanded
at their outer tips.
SHOE (1) A ground plate, forming a link of a track or
bolted to a track link. (2) A support for a bulldozer
blade or other digging edge to prevent cutting down.
(3) A clean-up device following the buckets of a
SIDECASTING Piling spoil alongside the excavation
from which it is taken.
SNATCH BLOCK A pulley in a case that can be easily
fastened to lines or objects by means of a hook, ring,
SPILLWAY An overflow channel for a pond or a
SPROCKET A gear that meshes with a chain or a
STOCKPILE Material dug and piled for future use.
SUPERCHARGER A blower that increases the intake
pressure of an engine.
SURGE BIN A compartment for temporary storage.
SWELL (Growth) Increase of bulk in soil or rock
when it is dug or blasted.
SWING LOCK A swing lock is a mechanical
engagement device, not dependent on friction, to
hold the upper structure in one or more fixed
positions with respect to the undercarriage. When
provided, it must be constructed to prevent
unintentional engagement or disengagement.
SWING BRAKE (Dynamic) A dynamic swing brake
is a device to stop, hold, or retard the rotating motion
of the upper structure with respect to the
SWITCHBACK A hair-pin curve.