Industrial Mechanics 4th Edition Chapter 7: Lifting
eyebolt
A bolt with a looped head.
block and tackle
A combination of ropes and sheaves (pulleys) used to improve lifting efficiency.
cab
A compartment or platform attached to a crane in which an operator may ride.
hand chain
A continuous chain grasped by an operator to operate a pocket wheel.
overhead crane
A crane that is mounted between overhead runways.
jib crane
A crane that is mounted on a single structural leg.
lattice-boom crane
A crane with a boom constructed from a gridwork of steel reinforcing members.
telescopic-boom crane
A crane with an extendable boom composed of nested sections.
gantry crane
A crane with structural beam supports for lifting equipment.
industrial crane
A crane with structural beam supports for lifting equipment.
limit switch
A device that cuts off the power automatically at or near the upper limit of hoist travel.
power-operated hoist
A hoist operated by pneumatic or electric power and uses either chain or wire rope as the lifting component.
lever-operated hoist
A lifting device that is operated manually by the movement of a lever.
hand-chain hoist
A manually operated chain hoist used for moving a load.
hoist
A mechanical device used to provide the lifting force on lead lines.
ratchet
A mechanism that consists of a toothed wheel and a spring-loaded pawl.
pawl
A mechanism used to prevent a ratchet wheel from turning backwards.
worm gear drive
A pair of gears consisting of a spiral-threaded worm (worm gear) and a worm wheel (driven gear) that are used extensively as a speed reducer.
bevel gear drive
A pair of gears that mesh at an angle, usually 90°.
pneumatic hoist
A power-operated hoist operated by a geared reduction air motor.
cantilever
A projecting beam or member supported at only one end.
pocket wheel
A pulley-like wheel with chain link pockets that is connected to a hoist mechanism.
pendant
A pushbutton or lever control suspended from a crane or hoisting apparatus.
end truck
A roller assembly consisting of a frame, wheels, and bearings generally installed or removed as complete units.
part
A rope length between the lower (hook) block and the upper block or drum.
slip clutch
A spring-loaded, friction-held fiber disc that is adjusted to slip at 125% to 150% of the hoist rated load.
reel
A wooden assembly on which wire rope is wound for shipping and storage.
crossover
One wrap winding on top of the preceding wrap.
reeving
Passing a rope through a hole or opening or around a series of pulleys.
inching
Slow movement in small degrees.
hoist chain
The chain that raises a load.
tackle
The combination of ropes and block assemblies arranged to gain mechanical advantage for lifting.
reach
The distance between the cup of a top hook and the cup of a hoist hook when the hoist hook is at its lower limit of travel.
hand-chain drop
The distance between the lower portion of a hand chain to the upper limit of the hoist hook travel.
headroom
The distance from the cup of the top hook to the cup of a hoist hook when the hoist hook is at its upper limit of travel.
lead line
The part of a rope to which force is applied to hold or move a load.
bridge girder
The principal horizontal beam that supports a hoist trolley and is supported by end trucks.
runway
The rail and beam on which a crane operates.
mechanical advantage
The ratio of the output force to the input force of a device.
drum wrap
The rope length required to make one complete turn around the drum of a hoist or crane.
hook drift
The slippage of a hook caused by insufficient braking.
ambient temperature
The temperature of the air surrounding a piece of equipment.
torque
The twisting (rotational) force of a shaft.
hoist trolley
The unit carrying the hoisting mechanism that travels on a bridge girder.
block
An assembly of one or more sheaves in a frame.
becket
An attachment point, usually on a block, for the dead end of a hoisting rope.
unthread rotation
Counterclockwise rotation of an eyebolt having right handed threads, or the clockwise rotation of an eyebolt having left handed threads.
lifting
Hoisting equipment or machinery by mechanical means.
lift (hoists)
In hoisting, the distance between the hoist's upper and lower limits of travel.