Rigging Equipment 121

6 x 19

A specific grade of wire rope. 6 x 19 wire rope is made from six strands that each contain nineteen wires.

A-frame

A structure consisting of two poles are connected at a 45° angle that can bear a light load. A-frames can be formed with shear lashings.

basket hitch

A sling configuration made from an endless sling that is used to form a cradle for the load. Basket hitches are typically used in pairs.

bends

A type of knot that is used to join two pieces of rope. Bends include square-reef, single-sheet, and double-sheet bends.

birdcaging

Permanent damage that occurs when strain causes the strands of a rope to protrude in a form resembling a birdcage. Birdcaging is caused by shock loads.

blocks

A pulley with one or more sheaves on a single axle, often encased in a shell. Blocks are used in both movable and fixed pulleys.

bridle hitches

A sling configuration made up of multiple slings attached to a master link. A bridle hitch is used to help balance a load by distributing the weight more evenly.

cable-laid

A fiber rope lay configuration in which three hawser-laid lines are twisted in the left-hand direction to form a thicker rope, or cable. Cable-laid rope typically is typically used for extremely heavy loads.

chain slings

A metal sling consisting of chain links and attachment devices. Chain slings are durable and used for lifting heavy loads.

chains

A series of interlocking metal rings or connected metal links. Chains are used for pulling, connecting, and securing heavy loads that may be exposed to heat or that have sharp edges.

choker hitch

A sling configuration that forms a loop around the load or attachment device and tightens as tension is increased. A choker hitch is used for loads that are irregularly shaped and difficult to balance.

clamp

A device that is used to fasten and bind parts of a rope to secure an eye splice. Clamps may be permanently affixed to a rope or be removable.

clevis hooks

A type of hook that attaches to lifting devices such as slings, ropes, or chains via a bolt or pin at its base. Clevis hooks can be removed from the lifting device by removing the pin or bolt.

clove hitch

A type of fastening made by looping a rope around an object twice and pulling the ends of the rope taut in opposite directions. Clove hitches can be adjusted easily after tying.

coir

A material that comes from coconut husks. Coir is used to make natural fiber rope that is light and flexible.

connecting link

A small oblong metal ring used to attach slings to loads and lifting equipment. Connecting links connect to a master link or to the ends of a sling or chain.

core

The inner part of a rope around which strands are twisted to give the rope more strength. The core of a rope can be made from the same material as the rest of the rope or be made from other materials.

cotter pin

A pin with two ends originally positioned together that are fitted through a hole and then bent backwards to lock the pin and other components in place. Cotter pins are found on some shackles.

cotton

A material that comes from the cotton plant. Cotton is used to make fiber ropes that are very flexible but not as strong as other ropes.

cranes

A large industrial machine with a hoisting mechanism for lifting and moving extremely heavy loads. A crane provides both vertical and horizontal movement.

double-sheet bend

A fastening, created by tying a single-sheet bend and adding an additional turn, that is used on ropes of different thickness or rigidity. Double-sheet bends will come loose when not under tension but are more secure than single sheet bends when under a load.

endless sling

A rope, chain, or piece of synthetic webbing that forms an unbroken circle. Endless slings are also known as grommets.

eye and eye

A basic sling configuration made from a rope with an eye splice at each end. Eye and eye slings can be configured into choker hitches, used as single-leg slings, or configured into bridle hitches.

eye splice

A type of splice that is used to make a permanent loop at the end of a rope. Eye splices are often used with thimbles to increase the strength of the loop.

eyebolts

A bolt with a forged hole or loop at one end. Eyebolts can be either the standard or shoulder variety.

eyehooks

A hook with a permanent circular opening at its base. Eyehooks can come with or without a latch.

fiber rope

Rope made from thin pieces of material twisted to form strands. Fiber rope can be composed of natural fibers or synthetic fibers.

figure-eight knot

A fastening that is used to attach ropes of the same diameter. A square-reef bend can be used to tie parcels closed but is not secure enough to be used in most rigging applications.

fittings

A piece of hardware used to reinforce and secure ropes. Fittings include thimbles, clamps, and sockets.

flange

A flat, disc-shaped section of a shoulder eyebolt that creates a stable surface for the bolt. A flange prevents the bolt from moving from side to side within the hole that the bolt is screwed into.

forged eyebolts

An eyebolt made from metal that has been forged to form a solid loop, or eye. Forged eyebolts are used for extremely heavy loads.

fraying

The unraveling of rope fibers caused by friction, prolonged use, or damage to the rope. Fraying can be prevented by tying a stopper knot at the end of the rope, tying off the ends with wire, or, for some synthetic ropes, burning the ends.

grommet

A rope, chain, or piece of synthetic webbing that forms an unbroken circle. Grommets are also known as endless slings.

hawser-laid

A fiber rope lay configuration in which three strands are twisted in the right-hand direction. Hawser-laid rope is the most common type of rope and is used to make cable-laid rope.

headache balls

A heavy round weight attached to a hook to keep the lifting cable taut. Headache balls are typically used on large cranes.

hitch

A knot that is used to tie a rope around a post or another object in order to secure it. Hitches are meant to be untied easily.

hoists

A motor-powered device that raises or lowers a load as a line winds or unwinds around a drum. A hoist may be part of a crane.

hooks

A curved device designed to fit into a hole or loop. Hooks are usually used with chains, hoists, and slings.

iron

A naturally abundant and commonly used metal that is very strong. Iron is very inexpensive but is susceptible to oxidation.

kinking

Damage to rope caused by bending it sharply. Kinking causes permanent damage to rope by causing the individual strands, fibers, or wires to bear a load unevenly.

knot

A fastening that is formed by tying a rope to another object or to itself. Knots should be easy to tie and untie, and they should hold without slipping.

lang lay

A wire rope lay configuration in which the strands and wires are wound in the same direction. Lang lay is more flexible than regular lay rope but is susceptible to birdcaging.

lashing

A rope, cord, or chain used to bind two objects, often poles, together. Lashings can be used to lengthen or reinforce poles or to bind poles at an angle.

lay

The direction in which the strands of a rope are twisted. The lay of a rope affects its strength, durability, and resistance to kinking.

links

A metal ring used to attach slings to loads and lifting equipment. Links can be oblong, pear-shaped, or round.

loads

The object or force that a lifting device must move or overcome. Loads, such as equipment or parts that need to be carried or moved, must not weigh more than the rigging equipment's working load limit.

long splice

A type of splice that creates very little increase in the diameter of the rope. Long splices are used when running rope through blocks or sheaves.

Manila

A material that comes from the leaves of the abaca, a type of banana tree that grows in the Philippines. Manila is used to make natural fiber rope that has a very high degree of strength and durability.

master link

A large oblong link used to attach slings to loads and lifting equipment. Master links are used to make single-, double-, triple-, and quadruple-leg slings.

master link

A sling configuration made from an endless sling that is used to form a cradle for the load. Basket hitches are typically used in pairs.

mesh slings

A sling made from a flat strip of woven material, such as metal wires or synthetic fibers. Mesh slings include wire mesh slings and synthetic web slings.

millwrights

A person who specializes in rigging. Millwrights oversee the rigging and moving of heavy loads, as well as the installation and leveling of rigging equipment.

natural fibers

Material that comes from plants such as Manila, sisal, coir, and cotton. Natural fiber rope is not as strong as synthetic fiber rope but is less prone to slippage.

nylon

An artificial material made from polymers. Nylon rope is stronger and more resilient than natural fiber rope.

overhand knot

A simple type of fastening made by twisting a rope into a loop and inserting one end of the rope through the loop. Overhand knots are the basis of many other types of knots.

padding

A layer of thick material that sits in between a sling and a load. Padding protects the sling from being cut by sharp edges of the load and protects the load from being scraped by the sling.

pear-shaped links

A link in the shape of a pear that is used to connect chains. A disadvantage of pear-shaped links is that they can slip and be turned upside down, causing the narrow end of the link to bend and become weakened.

pin

A cylindrical fastening device that closes the end of a shackle or clevis hook. A pin is often threaded on one or both ends.

pivot

To turn 180 degrees. Some eyebolts pivot along a hinge.

polyester

An artificial material used for its strength and resistance to ultraviolet deterioration. Polyester rope is more water resistant and less elastic than nylon rope.

polypropylene

An artificial material used for its strength and light weight. Polypropylene rope is stronger than Manila rope and is resistant to abrasion and chemicals.

pulley systems

A type of simple machine consisting of circular devices that raise or lower a load or transmit motion. Pulley systems consist of two or more pulleys.

regular lay

A wire rope lay configuration in which the strands and wires are wound in opposite directions. Regular lay is resistant to kinking and crushing.

reverse lay

A wire rope lay configuration in which each strand's wires are wound in the opposite direction of the wires in the adjacent strand. Reverse lay is more flexible than regular lay and less prone to birdcaging than lang lay.

riggers

Someone who is involved in the moving and securing of heavy loads at a worksite. Riggers include not only millwrights but also anyone involved in the rigging process.

rigging

The process of lifting and moving heavy loads with ropes, chains, and mechanical devices. Rigging is overseen by millwrights.

rings

A type of link that is round. Rings can form chains or be connected to the end of a chain.

ropes

A length of fibers or wires that are twisted together for strength. Ropes are used for pulling, connecting, and securing loads.

round lashing

A type of lashing used to connect two poles together. Round lashings strengthen the poles and extend their length.

saddle

The removable bottom of a U-bolt clamp. The saddle is secured to the rest of the bolt by nuts.

safety latches

A hinged fastening that prevents a load from slipping off a hook. Safety latches open inwardly, allowing loads to be connected easily, but do not open outwardly.

seizing

A method of forming an extremely strong connection to a wire rope by wrapping and tightening a wire around the rope. Seizing prevents a rope from fraying or unraveling when cut.

shackle

A U-shaped piece of metal that is closed at the end with a pin or bolt. Shackles connect slings to the load being lifted.

shackles

A U-shaped piece of metal that is closed at the end with a pin or bolt. Shackles connect slings to the load being lifted.

shear lashing

A type of lashing used to connect two poles together so that the angle at which they are connected can be adjusted. Shear lashings are named after the shape that the connected poles make, which resembles a pair of scissors.

sheaves

The freely moving wheel that is part of a moveable pulley. The sheave usually contains a groove to hold a rope or chain.

short splice

A type of splice that is extremely strong but increases the diameter of the rope significantly. Short splices are stronger than long splices.

shoulder eyebolt

An eyebolt that has a flange at the base of the loop. The shoulder eyebolt's flange prevents it from sinking into the surface to which it is bolted when side forces impact the load.

shroud-laid

A rope lay configuration in which four strands are twisted in the right-hand direction around a central core. Shroud-laid rope is resistant to kinking.

single-leg sling

A sling configuration in which one end is fastened to a hook or shackle and the other suspends the load on a single line of rope or chain. Multiple single-leg slings can be combined on a master link to form bridle hitches.

single-sheet bend

A fastening that is used to attach ropes of different thicknesses or rigidities. Single-sheet bends are secure when under tension but have a tendency to come loose when not under load.

sisal

A material that comes from the leaves of the agave plant, which grows in Mexico. Sisal is used to make natural fiber rope that is lighter than Manila rope and 80% as strong.

slings

A length of material used to connect a load to a lifting device. Slings can be made of rope, chain, wire, metal mesh, or webbing.

socket

A type of fitting that can be installed and removed quickly and easily. Sockets are secured with a removable pin.

splicing

A method of joining two ends of rope by unlaying the strands, placing the rope ends together, and interweaving the strands. Splicing can repair a rope, but it increases the diameter of the rope.

square knot

A fastening that is used on ropes of the same diameter. Square knots, also known as square-reef bends, slip under heavy loads.

square lashing

A type of lashing used to bind two poles together at a right angle. Square lashings can be used to make scaffolding.

square-reef bend

A fastening that is used on ropes of the same diameter. A square-reef bend can be used to tie parcels closed but is not secure enough to be used in most rigging applications.

standard eyebolt

An eyebolt with a shaft that leads directly to a circular opening. The standard eyebolt is used only for vertical lifting.

steel

A metal consisting of iron and carbon, usually with small amounts of other elements. Steel is used to make wire rope because it is strong but relatively inexpensive.

stopper

A type of knot that forms a knob at the end of a rope. Stoppers prevent a rope from fraying or passing through openings.

swivel

To turn 360 degrees. Some eyebolts swivel to allow rotary motion of the load or to allow the eyebolt to be positioned so that a hook can be easily attached.

swivel hooks

A type of hook with a rotating joint at its base that permanently attaches to lifting devices such as slings, ropes, and chains. Swivel hooks may be rotated to make it easier to attach them to loads.

synthetic fibers

Material that comes from man-made substances such as nylon, polyester, polyethylene, and polypropylene. Synthetic fiber rope is stronger than natural fiber rope but more prone to slippage.

synthetic web slings

A sling made of woven synthetic materials such as nylon, polyester, and polypropylene. Synthetic web slings are suitable for lifting fragile loads.

thimble

A pear-shaped piece of hardware used to reinforce the loop in an eye splice. Thimbles protect the rope from damage.

threads

A long, spiraling ridge around the outside of a cylindrical shaft. Threads allow eyebolts to securely fasten to a load and turnbuckles to be loosened and tightened.

throat opening

The open area near the point of a hook. The throat opening is one of the first places to show wear on a hook.

timber hitch

A type of fastening made by tying a rope around an object and looping the end of the rope through the knot several times to secure it. Timber hitches are useful when dragging or pulling loads

turnbuckle

An adjustable fitting that connects two lines or connects a line to a fixed point. The end fittings of a turnbuckle can be eyes, hooks, or jaws, and they can be used in any combination.

U-bolt

A commonly used clamp with a removable bottom that is placed around a rope and secured with two nuts. U-bolts may be used to connect two pieces of rope, to connect a rope to another device, or to secure an eye splice.

wedge socket

A commonly used socket for applications that require the length of a rope to change frequently. Wedge sockets are secured with a socket pin that is easy to remove.

wire mesh slings

A sling made from a flat belt of metal wire mesh. Wire mesh slings are useful for loads that would damage rope slings.

wire rope

Rope made from strands of steel or iron. Wire rope is used for jobs that require the rope to be extremely strong and resistant to abrasion.