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Captain Steve
Crane and
Hoist Terms and Definitions
Abnormal Operating Conditions - Environmental
conditions that are unfavorable, harmful, or detrimental to or for
the operation of a hoist , such as excessively high or low ambient
temperatures, exposure to weather, corrosive fumes, dust laden or
moisture laden atmospheres, and hazardous locations.
Anchor Bolt - A bolt used with its head
embedded in masonry or concrete and its threaded part protruding
to hold a jib crane in place.
Anchor Bolt Load - The total amount
of force that is applied to each supporting anchor bolt in a jib
crane; usually measured in kips.
ANSI American National Standards Institute
Appointed Assigned specific responsibilities
by the employer or the employers representative.
ASCE Rail - The runway rails on top
running cranes that the bridge travels on.
Automatic Crane A crane which when
activated operates through a preset cycle or cycles.
Auxiliary Hoist A supplemental hoisting
unit of lighter capacity and usually higher speed than provided
for the main hoist.
Axial load - The total vertical force
applied to the supporting structure in a jib crane. Formula: Axial
load= (overall weight of the crane) + (design factor x weight of
load)
Bay - The space between the building
frames measured parallel to the crest of the building.
Below-the-hook Lifting Devices - Devices
that are not normally reeved onto the hoist rope or chain, such
as hook-on buckets, magnets , grabs, and other supplemental devices
used for ease of handling certain types of loads. The weight of
these devices is to be considered part of the load to be lifted.
Boom - The horizontal beam (track) upon
which a hoist trolley travels. The jib of the jib crane.
Bracket Center - The distance, center
line to center line, between two supporting brackets of a wall mounted
jib crane (i.e. the distance between the two wall mounting points).
Brake - A device for slowing or, stopping
motion by friction or by electrical means.
Brake, Mechanical Load - An automatic
type of friction brake in the hoist that is used for controlling
loads in a lowering direction. This unidirectional device requires
torque from the motor or hand chain wheel to lower a load but does
not impose any additional load on the motor or hand chain wheel
when the hoist is lifting a load. A mechanical load brake is a mechanical
control braking means.
Braking Means - A method or device used
for stopping or holding motion of the hoist by friction or power.
Braking Means, Control - A method of
controlling hoist speed by removing energy from the moving body
or by imparting energy in the opposite direction.
Braking Means, Counter-torque (Plugging)
- A method of control by which the power to the motor is reversed
to develop torque in the direction opposite to the rotation of the
motor.
Braking Means, Dynamic - A method of
controlling hoist speed by using the motor as a generator, with
the energy being dissipated by resistance.
Braking Means, Eddy Current - A method
of controlling or reducing hoist speed by means of an energy induction
load brake.
Braking Means, Mechanical - A method
of controlling or reducing hoist speed by friction.
Braking Means, Pneumatic - A method
of controlling or reducing hoist speed by means of a compressed
gas.
Braking Means, Regenerative - A method
of controlling hoist speed in which the electrical energy generated
by the motor is fed back into the power system.
Block Loads - An action that facilitates
the removal of slings or other lifting devices from under the load,
accomplished by bringing the load to rest on wood, metal, or other
spacers between the floor and load.
Bridge - The main travelling structure
of the crane which spans the width of the bay. The bridge consists
of two end trucks and one or two bridge girders.
Bridge Girder(s) - The primary horizontal
beam of the crane bridge which supports the trolley and is supported
by the end trucks.
Bridge Travel The crane movement in
a direction parallel to the crane runway.
Bridge, Trolley and Lift Speeds - The
rate at which the bridge or trolley travels, or at which the hoist
lifts, usually in feet per minute or FPM.
Building Aisle - A space defined by
the length of a building and the space between building columns.
Bumper [buffer] An energy absorbing
device for reducing the impact when a moving crane or trolley reaches
the end of its permitted travel; or when two moving cranes or trolleys
come in contact.
Cab The operators compartment on
a crane
Cab Operated Crane A crane controlled
by an operator in a cab located on the bridge or trolley.
Cantilever Gantry Crane A gantry or
semi-gantry crane in which the bridge girders or trusses extend
transversely beyond the crane runway on one or both sides.
Capacity - The maximum weight in tons
the crane will be required to lift.
Chain Guide - A means to guide the hoist
load chain at the load sprocket.
Chain Hoist A hoists used for lower
capacity, lighter duty applications and for projects in which cost
is a primary deciding factor.
Clearance The distance from any part
of the crane to a point of nearest obstruction.
Collectors - Contacting devices for
collecting current from the runway conductors. The mainline collectors
are mounted on the bridge to convey electrical current from the
runway conductors.
Conductors, bridge The electrical
conductors located along the bridge structure of a crane to provide
power to the trolley.
Conductors, runway [main] are the
electrical conductors located along a crane runway to provide power
to the crane.
Control Pendant A device that gives
an operator precise control over the motions of the crane.
Controller, spring return a controller
which when released will return automatically to a neutral position.
Counter-Torque A method of control
by which the power to the motor is reversed to develop torque in
the opposite direction.
Crane A machine for lifting and lowering
a load and moving it horizontally with the hoisting integral part
of the machine. Cranes whether fixed or mobile are driven manually
or by power.
Crane Aisle - The portion of the building
aisle in which the crane operates, defined by the crane span and
the continuous length of the crane runway.
Crane girder(s) See Bridge Girder(s).
Crane Span - The horizontal distance
center to center of the both runway beams.
Deflection - The difference in elevation
at the tip of the boom between an unloaded jib crane and a fully
loaded jib crane; usually measured in inches. Our Jib Crane designs
tend to have stricter deflection criteria than others in the industry.
Designated Person - A person selected
or assigned by the employer or the employer's representative as
being competent to perform specific duties.
Double Girder - An overhead crane consisting
of two end trucks, two bridge girders and the trolley hoist unit.
The trolley runs on rails on top of the bridge girders.
Drag Brake A brake which provides
retarding force without external control.
Drift Point A point on a travel motion
controller which releases the brake while the motor is not energized.
This allows for coasting before the brake is set.
Drum The cylindrical member around
which the ropes are wound for raising or lowering the load.
Dynamic a method of controlling crane
motor speeds when in the overhauling condition to provide a retarding
force.
Electrification System - The various
parts of the crane structure that supply and apply electricity to
the trolley hoist.
Emergency Stop Switch A manually or
automatically operated electric switch to cut off electric power
independently of the regular operating controls.
Enclosures - The enclosures house all
of the electrical components on the crane.
End Stop - A device to limit the travel
of a trolley or crane bridge. This device normally is attached to
a fixed structure and does not normally have energy absorbing capability.
End Trucks - Located on either side
of the span, the end trucks house the wheels on which the entire
crane travels. These wheels ride on the runway beam allowing access
to the entire length of the bay.
Equalizer A device which compensates
for unequal length or stretch or a rope.
Exposed Capable or being contacted
inadvertently. Applied to hazardous objects not adequately guarded
or isolated.
Fail-safe A provision designed to
automatically stop or safely control any motion in which a malfunction
occurs.
Floor-Operated Crane A crane which
is pendant or nonconductive rope controlled by an operator on the
floor or independent platform.
Footwalk - A walkway with handrail,
attached to the bridge or trolley for accessibility purposes.
Foundation - Free Standing jib cranes
require that a special foundation, usually of concrete and steel,
be used to support the crane and prevent the crane from tipping
over. Foundation recommendations can be found in the price pages
and in the installation manual.
Gantry Cranes - An overhead crane where
the bridge girder(s) are connected to legs on either side of the
span. These legs eliminate the supporting runway and column system
and connect to end trucks which run on a rail either embedded in,
or laid on top of, the floor.
Hand Chain - The chain grasped by a
person to apply force required for the lifting or lowering motion
of the hoist.
Hand Chain Wheel - A wheel with formed
pockets on its periphery to allow torque to be transmitted when
a force is applied to the hoist hand chain.
Hand Geared - The operation of the bridge,
hoist, or trolley of a crane by the manual use of chain and gear
without electric power.
Height Under Boom (HUB) - The distance
from the floor to the underside of a jib crane's boom. The minimum
height under boom equals the height of the load, plus the maximum
distance the load is to be lifted, plus the headroom required for
the hoist, trolley, and attachments.
Hoist - A mechanical unit that is used
for lifting and lowering a load via a hook or lifting attachment.
Hoist Chain The load bearing chain
in a hoist.
NOTE: Chain properties do not conform to those
shown in ANSI B30.9-1971, Safety code for slings
Hoist Motion The motion of a crane
which raises and lowers a load.
Holding Brake - A brake that automatically
prevents movement when there is no power.
Hook Height -See Lift Height.
Hot Metal Handling Crane An overhead
crane used for transporting or pouring molten material.
Idler Sprocket - A freely rotating device
that changes the direction of the hoist load chain.
Jib Crane - A crane consisting of a
boom which is supported as a cantilever on a column.
Lift Height - The maximum safe vertical
distance that the hook can travel from the floor
Lifting Devices - See Below-the-hook
Lifting Devices
Limit Device - A device that is operated
by some part or motion of a power driven hoist to limit motion.
Limit Switch - A device designed to
disconnect the power automatically at or near the limit of travel
for the crane motion.
Load - The total superimposed weight
on the hoist load block or hook.
Load Block - The assembly of hook or
shackle, swivel, bearing, sheaves, sprockets, pins, and frame suspended
by the hoisting rope or load chain. This shall include any appurtenances
reeved in the hoisting rope or load chain.
Load Chain - The load-bearing chain
in a hoist.
Load Sprocket - A hoist component that
transmits motion to the load chain. This hoist component is sometimes
called load wheel, load sheave, pocket wheel, or chain wheel.
Load Suspension Parts - The load suspension
parts of the hoist are the means of suspension (hook or lug), the
structure or housing which supports the drum or load sprocket, the
drum or load sprocket, the rope or load chain, the sheaves or sprockets,
and the load block or hook.
Magnet An electromagnetic device carried
on a crane hook to pick up loads magnetically
Main Hoist The hoist mechanism provided
for lifting the maximum rated load.
Main Switch A switch controlling the
entire power supply to the crane.
Man Trolley A trolley having an operators
cab attached thereto.
Mast - The vertical steel component
of a jib crane which supports the crane. Free Standing jib cranes
(including Work Station Jibs) have a circular pipe for a mast, Wall
Cantilever cranes have standard I-beams, and Mast Type cranes have
wide flange beams. Wall Bracket cranes do not have a mast.
Master Switch A switch which dominates
the operation of the contactors, relays or other remotely operated
devices.
Mechanical A method of control by
friction
Non-running Sheave - A hoist sheave
used to equalize tension in opposite parts of the rope or chain.
Because of its slight movement, it is not termed a running sheave.
Normal Operating Conditions - Conditions
during which a hoist is performing functions within the scope of
the original design.
Overhead Crane A crane with a movable
bridge carrying a movable or fixed hoisting mechanism and traveling
on an overhead fixed runway structure.
Overload - Any hoist load greater than
the rated load.
Over-travel Restraint - A device used
to prevent the hoists slack load chain from inadvertently being
lowered out of the load sprocket.
Parts (Lines) - Number of lines of rope
or chain supporting the load block or hook.
Pendant - The pendant gives the operator
precise control over the motions of the crane.
Pendant Station - Controls suspended
from the hoist for operating the unit from the floor.
Power-Operated Crane A crane whose
mechanism is driven by electric, air, hydraulic or internal combustion
means.
Power Supply - The electrical service
available in the building for which the crane is being designed.
Power Transmission Parts - Hoist machinery
components including the gears, shafts, clutches couplings, bearings,
motors, and brakes.
Primary Upper-limit Device - The primary
upper-limit device is the first limit device that will be activated
to control the upper limit of travel of the load block when a hoist
is equipped with more than one upper-limit device
Pulpit-Operated Crane A crane operated
from a fixed operator station not attached to the crane.
Qualified Person - A person who, by
possession of a recognized degree in an applicable field or a certificate
of professional standing, or who by extensive knowledge, training
, and experience, has successfully demonstrated the ability to solve
or resolve problems relating to the subject matter and work.
Radio Remote Control - The radio control
performs exactly like the pendant but operates using a radio frequency.
Rated load - The maximum load a crane
is designed to handle.
Reeving - A system in which a rope or
chain travels around drums, sheaves or sprockets.
Remote Operated Crane - A crane operated
by Radio Remote Controls.
Roller Chain - A series of alternately
assembled roller links and pin links in which the pins articulate
inside the bushings and the rollers are free to turn on the bushings.
Pins and bushings are press fit in their respective link plates.
Rope A wire rope, unless otherwise
specified.
Rotating Axle - An axle which rotates
with a wheel.
Running Sheave - A hoist sheave that
rotates as the load block is lifted or lowered.
Runway - The rails beams, brackets,
and columns on which a crane operates.
Runway Conductors - The main conductors
mounted on or parallel to the runway which provide electrical current
to the crane.
Runway Rail - The rail supported by
the runway beams on which the bridge travels.
Semi-Gantry Crane A gantry crane with
one end of the bridge rigidly supported on one or more legs that
run on a fixed rail or runway, the other end of the bridge being
supported by a truck running on an elevated rail or runway.
Side Pull - The component of the hoist
pull acting horizontally when the hoist lines are not operated vertically.
Single Girder - An overhead crane consisting
of two end trucks, a single bridge girder and the trolley hoist
unit. The trolley runs on the bottom flange of the bridge girder.
Span - See Crane Span
Span (Jib Crane) - For a jib crane,
span is the distance from the center of the pivot point to the end
of the boom. Note that "span" is greater than actual working
span or hook coverage.
Standby Crane A crane which is not
in regular service, but is used occasionally or intermittently as
required.
Stop A device to limit travel of a
trolley or crane bridge. This device is normally attached to a fixed
structure and does not have energy absorbing ability.
Storage Bridge Crane A gantry type
crane of long span used for bulk storage of material; the bridge
girders or trusses are rigidly or non-rigidly supported on one of
more legs. It may have one or more fixed or hinged cantilever ends.
Support Column - A separate column which
supports the runway beam of a top running crane.
Supporting Structure (Jib Crane) - For
a free standing jib crane the supporting structure is the foundation
which the crane is bolted to or implanted in. For a wall bracket
or wall cantilever jib crane, the supporting structure is the wall
or column to which the crane is bolted. Mast type jib cranes have
a supporting structure at both the ceiling and the floor.
Suspension system - The system (rigid
or flexible) used to suspend the runway beams of under hung or monorail
cranes from the rafter of the building frames.
Switch - A device for making, breaking,
or changing the connections in an electric or pneumatic circuit
(valve).
Thrust and Pull - Forces exerted by
a jib crane on its supporting structure. Thrust is the pushing (or
compressive) force exerted on the structure, while Pull is the tensile
force. Thrust and Pull are thus equal (but opposite in direction)
to each other. The maximum thrust and pull occurs when the crane
is loaded at full capacity.
Trolley - The mechanism that carries
the hoist across the bay along the bridge girder(s) navigating the
span.
Trolley Hoist - The unit consisting
of both the hoist and the trolley frame.
Trolley Travel - The trolley movement
perpendicular to the crane runway
Truck [Endtruck] The unit consisting
of a frame, wheels, bearings, and axles which supports the bridge,
girders or trolleys.
Top Running - The crane bridge travels
on top of rails mounted on a runway beam supported by either the
building columns or columns specifically engineered for the crane.
Under Running - The crane bridge travels
on the bottom flange of the runway beam which is usually supported
by the roof structure.
Variable Frequency Drive (VFD ) - A
device used in conjunction with a pendant to vary the frequency
of the motors controlling the motions allowing for smooth acceleration
and deceleration.
Wall Crane A crane having a jib with
or without trolley and supported from a side wall or line of columns
of a building. It is a traveling type and operates on a runway attached
to the side wall or columns
Welded Link Chain - A hoist chain consisting
of a series of interwoven links formed and welded.
Wheel Base - The distance from center
to center of the outermost wheels.
Wheel Load - The load without impact
on any wheel with the trolley and lifted load (rated capacity) positioned
on the bridge to give maximum loading.
Wire Rope Hoist - A very durable hoist
that will provide long term, reliable usage.
Working Span - The working span (or
hook coverage) of a jib crane is less than the span of the crane.
It is a function of the maximum hook reach and the ability to get
the trolley close to the mast. Working span = (distance between
trolley stops) - (hoist trolley length)
