15
Appendix — Glossary
upper controls secondary battery — the backup power source for
ber optic upper controls.
upper pedestal — the structure within an elevator lift that connects
the elevator lift to the aerial device rotation bearing.
upper tool circuit — a tool hydraulic circuit with quick disconnect
couplings located at the upper boom tip.
vacuum — the absence of pressure. A perfect vacuum is the total
absence of pressure; a partial vacuum is some condition less than
atmospheric pressure. Vacuum is measured in inches of mercury
(in. Hg.).
valve — a device that controls uid ow direction, pressure or ow
rate.
vane pump — a type of pump with a rotor and several sliding vanes in
an elliptical chamber. Hydraulic uid enters the expanding area and is
forced out as the uid is moved to the decreasing chamber area.
variable displacement pump — a pump in which the size of the
pumping chamber(s) can be changed, so that the output ow can
be changed by moving the displacement control or varying the drive
speed or both.
vehicle — a carrier for a unit.
velocity — the speed of linear motion in a given direction.
velocity fuse — a hydraulic valve that is used to stop uid ow through
it when the ow rate reaches a predetermined cut-off value.
vent — an air breathing device on a uid reservoir or hydraulic line.
VI — see viscosity index.
viscosity — a measure of the internal friction or resistance to ow
of a uid.
viscosity index (VI) — a measure of the resistance to change in vis-
cosity of a uid with change in temperature. The higher the number,
the less the viscosity will change as the temperature changes.
voltmeter — an instrument used to measure the potential difference
in volts between two points in an electrical circuit.
volume — 1: the size of a space or chamber in cubic units. 2: loosely
applied to the output ow of a pump in gallons per minute (gpm).
vortex — a whirlpool of liquid.
waist harness — a belt device worn by the operator of a radio remote
control system to which the transmitter is attached.
walking beam outrigger — an extendible outrigger which has a pivot
point at the top of the nonextending leg and a linkage attached to the
extending leg, so that the leg assembly rotates about the pivot point
to increase the outrigger spread as it is extended.
warning — an instruction that indicates a potentially hazardous situation
which, if not avoided, could result in death or serious injury.
water monitor — an articulating mechanism that is used to direct the
ow of a high pressure water stream.
water removal lter cartridge — a special lter cartridge designed
to absorb and remove water from hydraulic uid. It is not intended
for use during normal operation, but is for use when water removal
is required.
way — a term which describes how many ports are in a valve or valve
section.
weldment — a structural unit formed by welding together an assembly
of pieces.
wheel chock — a wedge or block placed on the ground in front of or
behind the wheel of a vehicle to block the movement of the wheel.
winch — a mechanism consisting of a gearbox with a cylindrical rotating
drum on which to coil a line for load hoisting or line tensioning.
winch capacity — the maximum load, specied by the manufacturer,
that can be pulled on the rst layer of line on the winch drum at rated
system pressure.
winch line — a load hoisting line consisting of a synthetic or wire
rope.
winch line rated working load — the average breaking strength of
a winch line (as specied by the line manufacturer) divided by the ap-
propriate design factor as specied by ANSI.
wire rope — a rope made from steel wires which are formed into strands
that are then twisted about each other in a spiral conguration.
wood chipper — reduces above ground tree materials to uniform
chips.
work — the exertion of a force moving through a denite distance.
Work is measured in units of force multiplied by distance; for example,
pound-feet.
worm gearbox — a gearbox that utilizes a gear which has a continuous
helix tooth or teeth similar to a large screw thread along shaft (worm),
that drives a gear which has teeth cut at an angle along a its outside
diameter (worm gear). The rotational axis of the worm is perpendicular
to the rotational axis of the worm gear.
wrap — a single coil of winch line on a winch drum.
X-frame outrigger — an extendible outrigger having two diagonal
members which are connected at the top in an overlapping manner.
Resembles a broad based “X”.
Y-cable — an electrical cable assembly which contains three branches
joined at a common point, similar to a “Y.”
zerk — see grease tting.
To Next Page
Loading...