Crane terminology

Boom angle indicator

A device that measures and shows the angle of a crane or derrick's boom relative to horizontal

ASME

(American Society of Mechanical Engineers) promotes the art, science & practice of multidisciplinary engineering around the globe.

sheave

A grooved wheel used in a pulley.

Qualified person

A person who, by possession of a recognized degree, certificate, or professional standing, or by extensive knowledge, training, and experience, has demonstrated the ability to solve or prevent problems relating to a certain subject, work, or project.

outriggers

extendable or fixed members attached to the mounting base, which rest on supports at the outer ends used to support the crane

Load Moment

force applied to the crane by the load. The leverage the load exerts on the crane. Gross load times horizontal distance from the tipping axis to the load COG (center of gravity)

Net Capacity

gross capacity minus the deductions, total weight a crane may lift after gross deductions have been subtracted from the gross capacity.

boom hoist cylinder

hydraulic cylinder(s) used to raise or lower the boom changing the boom angle.

Boom length indicator

indicates the length of the permanent part of the boom(such as ruled markings on the boom) or, in some computerized systems, the length of the boom with extensions/attachments.

encroachment

is where any part of the crane, load line or load ( including rigging and lifting accessories) breaches a minimum clearance distance .

Blocking

is wood or other material used to support equipment or a component and distribute loads to the ground

Static Load

load is totally still, dead, without motion of any type.

LMI items that may have to be entered for configuration;

load weight, main and auxiliary line,# of parts of line utilized, using Main boom or jib, jib retracted or extended, on outrigger or rubber, outrigger extension %, code for the crane chart it will be using.

smooth

motion without any hesitation, abnormal vibration, binding, gross shimmy , or irregularity.

transit

moving or transporting of a crane from one job site to another.

certified person

person recognized for advanced knowledge and skill in crane operation. Certification is a voluntary process and involves successfully passing examinations designed by a accredited organization.

available line pull

pulling force on the rope from the drum. Ranges from high (bare drum) to low (full drum)

load

refers to the object(s) being hoisted and /or the weight of the object(s): both uses refer to the object(s) and the load-attaching equipment, such as the load block, ropes, slings, shackles, and any other ancillary attachment.

permissible line pull

safe working load , factory breaking strength divided by the design factor.. May be more or less than available line pull.

allowable line pull

safe working load, factory breaking strength divided by design factor. May be more or less then available line pull.

Cribbing

solid material place proportionately under the float pads to disperse the down pressure over a larger area of the ground, reducing the lbs./sq. inch pressure and eliminating the sinking of the float pads.

appointed person

someone assigned a specific responsibility or task by the employer.

tip point

that point at which the crane will tip when the load moment caused by the load( including the effects of boom position, motion and momentum) is greater than the leverage provided by the gross vehicle weight of the crane and its outriggers.

structural competence

the ability of the machine and its components to withstand the stresses imposed by applied loads.

Boom angle

the angle between the longitudinal centerline of the boom and the horizontal. The boom longitudinal centerline is a straight line between the boom foot pin (heel pin) centerline and boom point sheave pin centerline.

jib angle to ground

the angle formed between the centerline of the jib and the level line through the base of the jib. Changes any time the boom angle changes. It is the boom angle minus the jib offset angle. THIS IS NOT JIB OFFSET or JIB ANGLE.

Fleet Angle

the angle formed by the lead of a rope at the extreme end of a drum with a line drawn perpendicular to the axis of the drum through the center of the nearest fixed sheave (expressed in degrees)

Fall Zone

the area ( including but not limited to the area directly beneath the load) in which it is reasonably foreseeable that partially or completely suspended materials could fall in the event of an accident.

Two- blocking

the condition in which the lower load block or hook assembly comes in contact with the upper load block or boom point sheave assembly.

Boom length

the distance for the centerline of the point sheave pin to the centerline of the boom hinge pin.

foot or base section

the first section of the boom , attached to the upper works by the heel pin.

Radius

the horizontal distance from the center of rotation to the center of the vertical hoisting line with a freely suspended load.

boom deflection

the initial result of the load being lifted off of the surface. Result is ; as the boom tip dips as a result of the lift , the load swings outward from the crane increasing the radius and decreasing the capacity.

reach

the maximum horizontal distance the hook can be extended from the center of rotation (or if rotation is not possible ) from the foot of the boom.

rated load

the maximum load for which a crane or individual hoist is designed and built. Rated load is shown on the equipment nameplate.

capacity

the maximum rated load a crane is designed to handle. Designated limit of operating characteristics based on specific conditions.

travel

the moving of the machine from one location to another on a job site.

tipping axis

the point or line at which the crane will tip. Commonly called the fulcrum. Can be set by tires, crawlers, or the outriggers on mobile cranes

superstructure

the rotating upper frame structure of the machine and the operating machinery mounted thereon.

swing

the rotation of the superstructure for movement of loads in a horizontal direction about the axis of rotation.

gross deductions

the total weight imposed by hoist ropes, rigging, hooks, blocks, crane attachments, and effective loads imposed by environmental factors such as wind, rain, snow, etc.

gross load

the total weight imposed on the crane including the weight of the gross deductions and the weight of the load.

gross capacity

the total weight that a crane may lift under ideal conditions.

axis of rotation

the vertical axis around which the crane superstructure rotates.

net load

the weight of an object to be lifted.

Boom stop includes boom stops ( belly straps with struts/standoff, telescoping boom stops, attachment boom stops, and back stops.

these devices restrict the boom from moving above a certain maximum angle and toppling over backward.

dedicated spotter(power lines)

to be considered a dedicated spotter, the requirements of 1926.1428 must be met and their sole responsibility is to watch the separation between the powerline and the equipment, load line and load including rigging and accessories and ensure through communication with the operator that the minimum approach distance is not breached.

Competent person

One who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them

operational aids

are devices that assist the operator in the safe operation of the crane by providing information or automatically taking control of a crane function. Examples; anti-two blocking device, rated capacity indicator, rated capacity (load) limiter, boom angle or radius indicator, lattice boom hoist disconnect device, boom length indicator, crane level indicator, drum rotation indicator, load indicator, load moment indicator (LMI), load pressure sensor, and wind speed indicator.

safety devices

crane level indicator,intergral holding /check value,horn

plugging

creating a braking motion with an electric or hydraulic motor by applying energy to reverse the motor.

Pitch Diameter

distance through the center of a drum or sheave from center to center of a rope passed about the outside edge of the sheave.

fly

a boom extension supported by pins that is attached to the boom head to provide an added boom length for handling specified loads. Generally the fly is used only as a straight extension to the boom.

duty cycle

a complete operation from preparation for lifting a load to its final deposition, or a series of such movements, the kind , amount, sequence, frequency, duration, and period of work performed. A factor in determining mechanical, control, and electrical duty classification and the design ratings of engines, generators, motors, gears, clutches, brakes, bearings, and other parts.

insulated link

a component normally installed between the hook and the lifting wire rope or lower load block to prevent the flow of electrical energy.

hook

a device attached to the load block or overhaul ball on which slings are placed to lift a load.

Pawl (dog)

a device for positively holding a member against motion in one or more directions.

drum rotation indicator

a device on a crane or hoist which indicates in which direction and at what relative speed a particular hoist drum is turning.

rated capacity (load) limiter

a device that automatically monitors radius , load weight, and load rating and prevents movements of the crane , which would result in an overload condition.

rated capacity indicator

a device that automatically monitors radius, load weight, and load rating and warns the crane operator of an overload condition.

whip hoist

a hoist using a single line to the hook without intervening tackle. Used for light load and fast speeds.

two-stage

a horizontal double-folding fly of lattice construction that provides two separate working lengths. A working length of the base fly in its erected position or with both sections of the two-stage fly erected.

vertical law

a law or regulation which applies to only the industry which it is listed in or intended for.

horizontal law

a law which pertains to all industries.

dynamic loading

a load introduced into the machine or its components by forces in motion. Accelerating, decelerating, and stopping all cause dynamic loading.

swivel

a load-carrying member with thrust bearings to permit rotation under load in a plane perpendicular to the direction of the load.

Authorized Person

a person approved or assigned by the employer to perform a specific type of duty or duties or to be at a specific location or locations at the jobsite.

reeving arrangement

a plan showing the path that a rope takes in adapting itself to all sheaves and drums of a piece of equipment.

pendant

a rope or strand of specified length with fixed end connections.

Reeving

a rope system in which the rope travels around drums and sheaves.

running rope

a rope that travels around sheaves or drums.

whip line (runner or auxiliary)

a secondary rope system usually of lighter load capacity than that provided by the main rope system.

running sheave

a sheave which moves as the load is raised or lowered.

double drum hoist

a simple drum hoist having two independent hoisting drums.

Extension (insert)

a structure or device used to lengthen a boom or jib. Extensions may be of lattice or beam construction.

power-controlled lowering

a system or device in the power train , other than the load hoist brake, that can control the lowering rate of speed of the load hoist mechanism .

Load Moment Indicator( or rated capacity )

a system which aids the equipment operator by sensing (directly or indirectly ) the overturning moment on the equipment, ie load multiplied by radius. compares this lifting condition to the equipment's rated capacity ,and indicates to the operator the percentage to capacity at which the equipment is working.

load moment limiter (rated capacity)

a system which aids the equipment operator by sensing (directly or indirectly) the overturning moment on the equipment (load multiplied by radius) it compares this condition to the cranes rated capacity and when the rated capacity is reached it shuts off power to those equipment functions which can increase the severity of loading on the equipment.

Auxiliary boom head

also called rooster sheave or boom nose. Its purpose is to separate the main and auxiliary hoisting line.

heel pin

also called the hinge pin or king pin, located at the bottom of the first boom section, it is the axis at which the main boom pivots on to adjust boom angle.

runway

an assembly of rails, beams, girders, brackets, concrete, and framework that provides a stable travel surface, within 1% of level, at any position of travel and that is capable of safely supporting the hoisting equipment in the operational configuration and with the operational loads.

tackle

an assembly of ropes and sheaves arranged for lifting, lowering, or pulling.

stowed

an attachment in its un-erected position on the crane. The stowed weight of the attachment must be deducted from the crane's lifting capacity.

stored

an attachment which has been completely removed from the crane and whose weight has no effect on the crane or its lifting capacity.

Jib

an extension attached to the boom point to provide added length for lifting specified loads. The jib may be parallel with the boom or offset to various angles.

boom( equipment other than tower crane)

an inclined spar, strut, or other long structural member which supports the upper hoisting tackle on a crane or derrick. an apparatus used for supporting the hoisting tackle. Booms are attached to the superstructure with the outer end supported by ropes leading to a mast, gantry, or A-frame, or by a hydraulic system. A boom may be a lattice or beam construction.

test load

any load or force used for testing, the magnitude of which is known within acceptable tolerances and is so certified by the facility test director. Test load shall be expressed in pounds.

Designated person

ANSI calls it someone selected by the employer as being competent perform the specific duties. OSHS calls it someone selected by the employer as being qualified t perform the specific duties.

ANSI

American National Standards Institute: A private, non-profit organization that coordinates the development and use of voluntary consensus standards in the United States.

eccentric reeving

when a multiple sheave block and boom tip has had the hoist wire strung (reeved) incorrectly causing the block to raise or lower at an undesirable angle (the block is crooked). This action causes extreme wear to the sheaves and wire rope and can cause the boom to be side loaded.