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Glossary of Rigging Terms and Definitions

Glossary of Wire Rope, Rigging, and Lifting Terms

Wire Rope Classifications

Wire ropes are classified by the number of strands as well as by the number of wires in each strand. For example, 6 x 7, 6 x 19, 6 x 37, etc., where the first number is the number of strands, and the second number is the number of wires in each strand. Note, however, that these are nominal classifications and may or may not reflect the actual construction of a given rope.

The 6 x 19 classification includes six strands with each strand consisting of 15 to 26 individual wires. The six strands of a 6 x 37 class wire rope are constructed of 27 to 49 individual wires. Other popular classifications include 19 x 7, 7 x 19, and 8 x 19.

Every wire rope has three basic components: the wires, strands, and core. The core may be either fibre (FC) such as sisal, manila or jute, or an Independent Wire Rope Core (IWRC), which is actually a smaller wire rope within the strands of the outer wire rope.

The wires themselves are predominantly high-carbon steel but may also be various other alloys or metals such as iron, stainless steel, Monel, or bronze. Carbon steel wire rope is manufactured in various grades, including Improved Plow Steel (IPS), Extra Improved Plow Steel (EIPS) and Extra Extra Improved Plow Steel (EEIPS), which designate the nominal strength of the wire rope. EIPS is the most commonly used and manufactured grade today.

While 6 x 19 ropes give primary emphasis to abrasion resistance in varying degrees, 6 x 37 ropes are important for their fatigue resistance. This fatigue resistance is made possible by the greater number of small wires per strand.

Rotation Resistant Wire Ropes

In an application where rotation-resistant properties are essential for rope performance, the 19 x 7 construction can be used. The rotation-resistant characteristic of this construction is achieved by laying six strands around a core strand in one direction, then laying 12 strands around the first operation in the opposite direction. Thus, when the rope is in tension, opposing rotational forces are created between the inner and outer layers.

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Aircraft cable is a common industry term for small diameter wire rope originally designed for aeronautical applications. It is a flexible and inexpensive cable used on winches, guy lines, and numerous other commercial, industrial, and marine applications. For corrosion resistance, aircraft cable is available with a zinc coating (galvanized) or in various stainless-steel alloys. Galvanized aircraft cable is also available with a flexible, PVC cover to extend the cable's life by protecting wires from abrasion, dirt, grit, and moisture, sealing in lubrication and reducing wear on sheaves and pulleys. The PVC cover also protects hands, clothes, and other materials with which the cable is in contact.

Acceleration stress - Additional stress imposed by an increase in the load velocity.

Aggregate strength - The wire rope strength derived by totalling the individual breaking strengths of the elements of the strand or rope. This strength does not recognize the reduction in strength resulting from the angularity of the elements in the rope or from other factors that may affect efficiency.

Alternate lay - Lay of wire rope in which the strands are alternately regular lay and lang lay.

Angle of loading - The inclination of a leg or branch of a sling measured from the horizontal or vertical plane, provided that an angle of loading of five degrees or less from the vertical may be considered a vertical angle of loading.

ANSI - American National Standards Institute.

API - American Petroleum Institute.

Armoured rope - See steel-clad rope.

ASME - American Society of Mechanical Engineers.

Basket hitch - A sling configuration whereby the sling is passed under the load and has both ends, end attachments, eyes or handles on the hook or a single master link.

Bearing life (rated life) - The number of revolutions or the number of hours at a constant speed that 90% of an apparently identical group of bearings will complete or exceed before the first evidence of fatigue develops, i.e., 10 out of 100 bearings will fail before rated life. Minimum life and L10 life are also used to mean rated life.

Becket - A wedge socket-type wire rope end termination.

Becket line - That part of the rope in a multiply reeving system that is dead-ended on one of the blocks.

Becket loop - A loop of small rope or strand fastened to the end of a large wire rope to facilitate installations.

Bird cage - A colloquial term describing the appearance of wire rope forced into compression. The outer strands form a “cage” and, at times, displace the core.

Bleeding line - A condition caused when wire rope is overloaded, forcing the lubricant in the cable to be squeezed out and run excessively.

Block - A term applied to a wire rope sheave (pulley) enclosed inside plates and fitted with some attachment such as a hook or shackle.

Braided wire rope - A wire rope formed by plaiting component wire ropes.

Breaking strength - The measured tensile load required to cause failure of cable, chain, wire rope, or any other load-bearing element.

Breaking strength/Ultimate strength - The average force at which the product, in the condition it would leave the factory, has been found by representative testing to break when a constantly increasing force is applied in direct line to the product at a uniform rate of speed on a standard pull testing machine.

Remember: breaking strengths, when published, were obtained under controlled laboratory conditions. Listing of the Breaking Strength does not mean the Working Load Limit should ever be exceeded.

Do not use breaking strength as a criterion for service of design purposes. Refer to the Working Load Limit instead.

Bridle sling - Sling composed of multiple wire rope legs with a fitting that attaches to the lifting hook.

Bright rope - Wire rope made of wires that are not coated with zinc or tin.

Brooming - Unlaying and straightening of strands and wires in the end of wire ropes during the process of installing a wire rope socket.

Bull ring - The main, large ring of a sling to which sling legs are attached; also called master link.

Bulldog clip - A wire rope cable clamp or clip.

Cable - A term loosely applied to wire ropes, wire strand, and electrical conductors. Wire rope is the preferred term for hoisting and rigging applications.

Cable-laid wire rope - A wire rope consisting of several independent wire ropes wrapped around a fibre or wire rope core.

Cable-laid endless sling-mechanical joint - A wire rope sling made endless by joining the ends of a single length of cable-laid rope with one or more metallic fittings.

Cable-laid grommet hand tucked - An endless wire rope sling made from one length of rope wrapped six times around a core formed by hand tucking the ends of the rope inside the six wraps.

Cable-laid rope - A wire rope composed of six wire ropes wrapped around a fibre or wire rope core.

Cable-laid rope sling - Mechanical joint is a wire rope sling made from a cable laid rope with eyes fabricated by pressing or swaging one or more metal sleeve over the rope junction.

Cheek plate(s) - The stationary plate that support(s) the pin (axle) of a sheave or load.

Cheek weights - Overhauling weights attached to the side plates of a lower load block.

Chinese finger - A wire mesh pulling grip, usually used with wire rope, into which a line is inserted and that tightens around the line when pulling force is applied.

Choker sling - Wire rope with eyes spliced on each end, which is used to lift the load.

Choker hitch - A sling configuration with one end of the sling passing under the load and through an end attachment, handle, or eye on the other end of the sling.

Clearance - The horizontal or vertical distance from any part of the crane to a point of the nearest obstruction.

Clevis - A U-shaped fitting with holes in each end through which a pin or bolt is run.

Clip - Fitting for clamping two parts of wire rope.

Closed socket - Wire rope end fitting consisting of integral basket and bail.

Coil - Circular bundle of wire or fibre rope not packed on a reel.

Come-along - Lever-operated chain or wire rope devices designed for pulling, not lifting; also called pullers. Unlike hoists, the tension is held by a releasable ratchet. Much smaller and lighter than hoists of equal capacity, they are not intended nor allowed for lifting but are suited for activities such as skidding machinery.

Conical drum - Grooved hoisting drum of tapering diameter.

Continuous bend - Reeving of wire rope over sheaves and drums so that it bends in one direction, as opposed to reverse bend.

Core - Member of wire rope about which the strands are laid. It may be fibre, a wire strand, or an independent wire rope.

Corrosion - Chemical decomposition by exposure to moisture, acids, alkalis, or other destructive agents.

Corrugated - A term used to describe the grooves of a sheave or drum when worn to show the impression of a wire rope.

Bridge crane - A crane with a single- or multiple-girder movable bridge, carrying a movable trolley or fixed hoisting mechanism, and travelling on an overhead fixed runway structure.

Crawler crane - A crane consisting of a rotating superstructure with power plant, operating machinery, and boom, mounted on a base, equipped with crawler treads for travel. Its function is to hoist, lower, and swing loads at various radii.

Double-girder crane - A crane having two bridge girders mounted between, and supported from, the end trucks.

Floor-operated crane - A power-operated crane that is controlled by an operator from the floor or an independent platform or walkway located in the crane way, using power control switches or push buttons on a pendant.

Gantry crane - A crane similar to an overhead bridge crane, except that the bridge for carrying the trolley or trolleys is rigidly supported on two or more legs running on fixed rails or other runways, usually 3 metres (10 feet) or more below the bottom of the bridge.

Jib crane - A fixed crane with a vertical rotating member supported at the bottom (also at the top in some types), from which an arm extends to carry the hoist trolley. Jib cranes are most commonly mounted on a vertical column, supplied as part of the jib crane or mounted on existing structural members (e.g., a wall-mounted jib crane).

Manually operated crane - A crane whose hoist mechanism is driven by pulling an endless chain or whose travel mechanism is driven in the same manner or by manually moving the load.

Overhead crane - A crane with a single or multiple girder movable bridge, carrying a movable trolley or fixed hoisting mechanism, and travelling on an overhead fixed runway structure.

Critical diameter - Diameter of the smallest bend for a given wire rope that permits the wires and strands to adjust themselves by relative movement while remaining in normal position.

Critical load - In accordance with ANSI N14.6: Any lifted load whose uncontrolled movement or release could adversely affect any safety-related system when such system is required for unit safety or could result in potential offsite exposures comparable to the guideline exposures outlined in Code of Federal Regulations, Title 10, Part 100.

Critical service - The use of equipment or tackle for hoisting, rigging, or handling of critical items, or other items in, around, or above spaces containing critical items.

Crossover points - In multiple-layer spooling of rope on a drum, those points of rope contact where the rope crosses the preceding rope layer.

D/d Ratio - A term regarding wire rope. D = Diameter of curvature around which the rope is bent. d = diameter of rope.

Example: With 0.5-inch-diameter rope passing over a 20-inch-diameter sheave, the D/d ratio is 40. The D/d ratio is a key factor in load-carrying ability and life span of a wire rope.

Dead end - The point of fastening of one rope end in a running rope system, the other end being fastened at the rope drum.

Deadman - An object or structure, either existing or built for the purpose, used as anchorage for a guy rope.

Deceleration stress - Additional stress imposed on rigging resulting from a decrease in load velocity.

Deflection - (a) The sag across a span of a load member caused by the imposed live and/or dead loads, which is usually measured at mid-span as the distance along a straight horizontal line drawn between the supports; (b) Any deviation from a straight horizontal line.

Derrick - An apparatus for lifting or lowering loads, consisting of a mast or equivalent member held at the head by guys or braces, with or without a boom, for use with hoists and ropes.

Design factor - The conservatism used in design calculations. As a function of design, this factor can be based upon the point of equipment failure, such as crane tipping and brake stopping capacity or based upon strength of materials, ultimate, nominal, or yield. Consensus standards express design factors as a ratio (for example, 5:1, 3:1, 3.5:1) or as a single number (for example, 5, 3, or 3.5, understood to mean the “X” to 1). Although “design factor” is sometimes referred to as a “safety factor,” “design factor” is the preferred term. An inexperienced person may incorrectly assume this factor of design conservatism will make up for such conditions as shock loading, poor rigging, improper equipment selection, and overload conditions.

Design factor (sometimes referred to as safety factor) - an industry term usually computed by dividing the catalogue Breaking Strength by the catalogue Working Load Limit and generally expressed as a ratio. For example, 4 to 1.

Diameter (wire rope) - The diameter of wire rope is the diameter of the circle that will contain the rope.

Dog leg - Permanent short bend or kink in wire rope caused by improper use.

DOT, U.S. - Department of Transportation.

Dragline - Wire rope used to pull an excavating or drag bucket. Also used as an expression of a particular type of mobile crane using a drag bucket during excavation.

Drum - (a) A cylindrical-flanged barrel of uniform (cylindrical drum) or tapering (conical drum) diameter on which cable is wound for operation or storage, which may be smooth or grooved; (b) The cylindrical member around which rope is wound for lifting or lowering the load or boom or swinging the boom supporting structure.

Drum capacity, rope - The length of a specific diameter of rope that can be wound on a drum.

Dynamic loading - Loads introduced into the machine or its components by forces in motion.

Efficiency (wire rope) - Ratio of a wire rope’s measured breaking strength and the aggregate strength of all individual wires tested separately, which is usually expressed as a percentage. The breaking strength of wire ropes seldom exceeds 90% of the aggregate strength of all the wires, the average being about 82.5%.

Elastic limit - Limit of stress above which a permanent deformation takes place within the material. This limit is approximately 55 to 65% of breaking strength of steel wire ropes.

End termination - The treatment at the end or ends of a length of wire rope, which is usually made by forming an eye or attaching a fitting, designed to be the permanent end termination on the wire rope that connects it to the load.

Endless rope - Rope whose two ends are spliced together.

Equalizing sheave - The sheave at the centre of a rope system over which no rope movement occurs other than equalizing movement. It is frequently overlooked during crane inspections, with disastrous consequences. It can be a source of severe degradation.

Extra-improved plow steel rope - See grades, rope.

Eye or eye splice - A loop with or without a thimble formed at the end of a wire rope.

Fabric (metal mesh) - The flexible portion of a metal mesh sling consisting of a series of transverse coils and cross rods.

Factor of safety - See design factor.

Fail-safe - A provision designed to automatically stop or safely control any motion in which a malfunction occurs.

Falls - See parts of line.

Fatigue - The phenomenon leading to fracture under repeated or fluctuating stresses having a maximum value less than the tensile strength of the material.

Fibre cores - Cords or rope made of vegetable or synthetic fibre used in the core of a wire rope.

Filler wire - Small auxiliary wires in a strand used for spacing and positioning other wires

Fitting - Any accessory used as an attachment for wire rope.

Flange point - A point of contact between rope and drum flange where the rope changes layers.

Flat rope - Wire rope made of parallel alternating right-lay and left-lay ropes sewn together by relatively soft wire.

Fleet angle - The maximum angle between a rope and the line perpendicular to the drum on which it winds.

Fleeting sheave - Sheave mounted on a shaft parallel to the rope-drum shaft and arranged so that it can slide laterally as the rope spools, permitting close sheave placement without excessive fleet angle.

Flemish eye - A type or method of making a wire rope eye splice.

Gage points - Permanent marks on a hook that are used to determine any change in the throat-opening dimension.

Galvanized rope - Wire rope made of galvanized wire.

Galvanized strand - Strand made of galvanized wire.

Grades, rope - Classification of wire rope by its breaking strength. Listed in order of increasing breaking strengths: iron, traction, mild plow steel, plow steel, improved plow steel, and extra-improved plow steel.

Grooved drum - Drum with a grooved surface that accommodates and guides the rope.

Grooves - Depressions in the periphery of a sheave or drum used for positioning and supporting a rope.

Handle eye - An opening in a handle of a metal mesh sling shaped to accept a hook, shackle, or other lifting device.

Hitch - A sling configuration whereby the sling is fastened to an object or load, either directly to it or around it.

Hoist - Noun: (a) A lifting device for raising or lowering loads. Its service area is vertical over its mounting. Hoists may be attached to fixed or movable structures by an upper hook or bracket and can be either power or manually operated; (b) A power-operated component of a crane or monorail system that provides torque to raise a load or lower it at a controlled speed and hold a load stationary; (c) A power-driven drum or drums capable of lifting and lowering loads. Verb: The action of raising a load.

Hook, rigging - A hook used as part of tackle. Any hook used in hoisting and rigging that is not the “primary hook” or main “load hook.”

Hook latch - A mechanical device to bridge the throat opening of a hook.

Horseshoe - A rope thimble.

Laced blocks - Passing wire rope through a set of blocks by starting from an outside sheave and following in rotation. Will usually tilt travel block when running empty.

Lang lay rope - Wire rope in which the wires in the strands and the strands in the rope are laid in the same direction. Synonymous with Albert’s lay.

Latch, hook - A device used to bridge the throat opening of a hook.

Lay (wire rope) - (a) The way the wires in a strand or the strands in a rope are helically laid, or (b) the distance measured parallel to the axis of the rope (or strand) in which a strand (or wire) makes one complete helical convolution about the core (or centre). In this connection, lay is also referred to as “lay length” or “pitch.”

Lead line - That part of a rope tackle leading from the first or fast sheave to the drum. Left-hand end - A reference to parts or dimensions on the viewer's left of the centreline of span, established when facing the drive girder side of the crane.

Left lay - (a) Strand – strand in which cover wires are laid in a helical pitch, similar to left-hand screw; (b) Rope – rope in which strands are laid in a helix having a left-hand pitch, similar to left-hand screw.

Lift - (a) Any sequence of operations in which a hoisting device raises an object above the ground, floor, or support, and then places it on the ground, floor, or support; (b) Maximum safe vertical distance through which the hook can travel; (c) the hoisting of a load.

Lift beam - See spreader beam.

Lifting devices - Devices that are not reeved onto the hoist ropes, such as hook-on buckets, magnets, grabs, load-spreader bars, and other supplemental units used for ease of handling certain types of loads. The weight of these devices is to be considered part of the working load.

Lifting eye - A point of attachment on the item to be lifted, having a looped head designed to accommodate a hook or shackle. Also called a slinging eye.

Limiting devices - A device that is operated by some part of a power-driven machine or equipment to control motions of the machine or equipment.

Line - Rope used for supporting and controlling a suspended load.

Line pull - The pulling force attainable in a rope leading off a rope drum or lagging at a particular pitch diameter (number of layers).

Line speed - The speed attainable in a rope leading off a rope drum or lagging at a particular pitch diameter (number of layers).

Link - A single ring of a chain.

Load - The total superimposed weight or force to be overcome by the hoisting and rigging equipment.

Load-bearing parts - Any part of a material-handling device in which the induced stress is influenced by the hook load. A primary load-bearing part is one, where the failure of which could result in dropping, upset, or uncontrolled motion of the load. Load-bearing parts which, if failed, would result in no more than stoppage of the equipment without causing dropping, upset, or loss of control of the load, are not considered to be primary load-bearing parts.

Load block, lower - The assembly of hook or shackle, swivel, sheaves, pins, and frame suspended by hoisting ropes.

Load block, upper - The assembly of sheaves, pins, and frame suspended from the hoisting platform or from the boom in mobile cranes.

Load, live - A load that moves or varies relative to the member being considered. For the trolley, the live load consists of the rated load plus the weight of the block. For the bridge, the live load consists of the rated load plus the weight of the trolley.

Load point - The point of load application.

Load point, auxiliary - Any point of load application other than the load point.

Load, rated - The maximum static vertical load for which a crane or an individual hoist is designed. See rated capacity.

Load rating - Rating in pounds established by the manufacturer.

Load, working load limit (WLL) - The maximum load a piece of equipment (or tackle) can handle without exceeding the rated capacity (the rated capacity of the lowest capacity item used in the lift). See load, rated.

Load, working - The external load, in pounds, applied to the crane. For mobile cranes and derricks, the weight of load-attaching equipment is included as part of the working load (e.g., load blocks, hooks, shackles, and slings). In permanently installed cranes such as overhead, gantry, and monorail cranes and hoists, the weight of the load block and hook is not part of the working load.

Locked coil strand - Smooth-surfaced strand composed of shaped wires laid in concentric layers around a centre of round wires.

Lowest service temperature (LST) - A predetermined temperature below which all lifting equipment, assemblies, or fixtures should not be used.

Magnet - An electromagnetic device carried on a crane hook that picks up loads magnetically.

Magnetic particle examination - A non-destructive test that reveals defects in ferromagnetic materials via detection of leakage fields at discontinuities in magnetic flow paths.

Marlin spike - Tapered steel pin used in splicing wire rope.

Master link - Forged or welded steel link used to support all members (legs) of an alloy-steel chain or wire rope sling (includes bull ring, pear link, oblong link, and weldless sling link). Also called bullring.

Master coupling link - An alloy steel welded coupling link used as an intermediate link to join alloy steel chain to master links.

Master link or gathering ring - A forged or welded steel link used to support all members (legs) of an alloy steel chain sling or wire rope sling.

Mechanical coupling link - A nonwelded, mechanically closed steel link used to attach master links, hooks, etc., to alloy steel chain.

Mild plow - See grades, rope.

Milking - The progressive movement of strands along the axis of the rope, resulting from the ropes movement through a restricted passage such as a tight sheave.

Molly Hagan - A type or method of making a wire rope eye splice. Same as a “Flemish eye.”

Mousing - A method of bridging the throat opening of a hook to prevent the release of load lines and slings, under service or slack conditions, by wrapping with soft wire, rope, heavy tape, or similar materials.

NCR – Non Conformance Report.

NDT – Non-destructive testing.

Nil-ductility transition temperature - The maximum temperature at which a standard drop-weight specimen breaks when tested in accordance with ASTM E-208.

Nominal strength, wire rope - Nominal wire rope strengths as calculated by a standardized industry-accepted procedure. Minimum acceptance strength is 22% lower than nominal strength. (Re: Wire Rope Users Manual.

Non-destructive examination (NDE) - A name applied to a variety of tests which make use of indirect means to locate material discontinuities (e.g., radiography, dye penetrant, magnetic particles, ultrasonic).

Non-rotating wire rope - See rotation-resistant rope.

Non-spinning wire rope - See rotation-resistant rope.

Parts of line - A number of running ropes supporting a load or force, also called parts or falls.

Paying out - Adding slack to a line or relieving load on a line by letting (spooling) out rope.

Pelican hook - 1) A sorting hook, also called a "shake out hook"; 2) A hinged hook with a long reach that can be opened or secured with a sliding ring; 3) generically, any hook with a long, deep reach.

Peening - Permanent distortion of outside wire in a rope caused by pounding.

Pitch diameter - The distance, measured through the centre of a drum or sheave, from centre to centre of a rope passed about the periphery of the drum or sheave.

Pig tail - A short, standard eye-eye wire rope sling, often used to connect between a crane hook and another wire rope sling or bridle; also known as a "messenger sling."

Pre-engineered lift - A lift for which a qualified individual or engineer independently pre-identifies load weight, load centre of gravity, lift attachment points, and minimum lifting hardware (slings, below-the-hook lifting devices, shackles, etc.) capacities that will be used for the lift or series of lifts.

Preformed strand - Strand in which the wires are permanently shaped, before fabrication in the strands, to the helical form they assume in the strand.

Preformed wire rope - Wire rope in which the strands are permanently shaped, before fabrication into the rope, to the helical form they assume in the wire rope.

Prestressing - Stressing a wire rope or strand before use under such a tension and for such a time that the construction stretch is largely removed.

Proof load - The load applied in performance of a proof test.

Proof test/load - the term “Proof Test” or “Proof Load” designates a quality control test applied to the product for the sole purpose of detecting defects in material or manufacture. The Proof Test Load (usually twice the Working Load Limit) is the load which the product withstood without deformation when new and under laboratory test conditions. A constantly increasing force is applied in direct line to the product at a uniform rate of speed in a standard pull testing machine. The Proof Test Load does not mean the Working Load Limit should ever be exceeded.

Pullers - Also called come-along.

Ratchet - A toothed member, attached to or a part of the drum, for engagement with the pawl.

Rated load (capacity) - (a) The maximum load designated by the manufacturer for which a crane, hoist, rigging, or other lifting device is designed and built; (b) For a truck equipped with load carriage and forks or attachments it is the weight established by the manufacturer or a registered professional engineer at a required load centre that a given truck can transport and stack to an established height.

Rated rope (line) pull - The manufacturer's recommended load in pounds (kilograms) applied to the rope attached to the hoist drum.

Reach - the effective length of an alloy steel chain sling measured from the top-bearing surface of the upper terminal component to the bottom bearing surface of the lower terminal component.

Reel - The flanged spool on which wire rope or strand is wound for storage or shipment.

Reeve - The pattern that a rope forms between sheaves in a hoisting system.

Reeved blocks - Passing rope through a set of blocks, as opposed to laced blocks, and in such a manner that there are no lines crossed or rubbing each other.

Reeving - A rope system in which the rope travels around drums and sheaves in a prescribed manner.

Reeving diagram - A diagram showing the path of the rope through a system of sheaves (blocks).

Regular-lay rope - Wire rope in which the wires in the strands and the strands in the rope are laid in opposite directions.

Repetitive pickup point - When operating on a short cycle operation, the rope being used on single layer and being spooled repetitively over a short portion of the drum.

Reverse bend - Reeving of a wire rope over sheaves and drums so that it bends in opposite directions.

Reverse lay - See alternate lay.

Right-hand end - A reference to parts or dimensions on the viewer's right of the centreline of span, established when facing the drive-girder side of the crane.

Right-lay - (a) Strand in which the cover wires are laid in a helix having a right-hand pitch, similar to a right-hand screw; (b) Rope in which the strands are laid in a helix having a right-hand pitch, similar to a right-hand screw.

Rigging - The act of attaching hoisting equipment to the load.

Rollers - Relatively small-diameter cylinders or wide-faced sheaves for supporting or guiding ropes.

Rope drum - That part of a drum hoist that consists of a rotating cylinder with side flanges, on which hoisting rope is spooled in or out (wrapped).

Rotation-resistant rope - A wire rope consisting of an inner layer of strands laid in one direction, covered by a layer of strands laid in the opposite direction. This has the effect of counteracting torque by reducing the tendency of the finished rope to rotate.

Running line - A rope that moves over sheaves or drums.

Running sheave - A pulley-type device that changes location in relation to the hoisting device.

Safe working load (SWL) - See rated (load) capacity.

Safety factor - See design factor.

Seale - A strand construction having one size of cover wires with the same number of one size of wires in the inner layer and each layer having the same length and direction of lay. Most common construction is one centre wire, nine inner wires, and nine cover wires.

Seize - To bind securely the end of a wire rope or strand with seizing wire or strand.

Seizing strand - Small strand, usually of seven wires, made of soft-annealed-iron wire.

Seizing wire - A soft-annealed-iron wire.

Selvage edge - The finished edge of synthetic webbing designed to prevent unravelling.

Serve - To cover the surface of a wire rope or strand with a wrapping of wire.

Service, normal - That service which involves operation with randomly distributed loads within the rated load limit, or uniform loads of less than 65% of the rated load for not more than 15% of the time for manually operated hoists and 25% of the time for electric- or air-powered hoists, of a single work shift.

Service, heavy - That service which involves operation within the rated load limit which exceeds normal service.

Service, severe - That service which involves normal or heavy service with abnormal operating conditions.

Shackle - A type of clevis normally used for lifting.

Shake out hook - A sorting hook; also known as a “pelican hook.”

Sheave - A wheel or pulley with a circumferential groove designed for a particular size of wire rope; used to change direction of a running rope.

Shock loading - Term used to call attention to the application of any sudden, unplanned loading of equipment that would jeopardize the safety of the lift. Typical examples that could result in shock loading are: (a) Rapid travel of the burden block without alteration of speed before all slack is removed from the sling(s), (b) Unplanned shifting of the load while suspended, (c) Fracture of a lifting system component resulting in the application of unknown loading on remaining components.

Shock load - A load resulting from rapid change of movement, such as impacting, jerking or swinging of a static load. Sudden release of tension is another form of shock loading. Shock loads are generally significantly greater than static loads. Any shock loading must be considered when selecting the item for use in a system. Avoid shock loads as they may exceed the Working Load Limit.

Side pull - That portion of the hoist pull acting horizontally when the hoist lines are not operated vertically.

Side loading - A loading applied at any angle to the vertical plane of the boom.

Slinging eye - See lifting eye.

Slings - Wire ropes, chains, or synthetic fabric made into forms, with or without fittings, for handling loads.

Slings, braided - A very flexible sling composed of several individual wire ropes braided into a single sling.

Slings, endless and grommet wire rope - A wire rope made endless from one continuous length of cable-laid rope with the ends joined by one or more metallic fittings.

Slings, four-leg bridle - Sling made with four single-rope legs, secured to a single lifting ring.

Slings, three-leg bridle - Slings made with three single-rope legs, secured to a single lifting ring.

Slings, two-leg bridle - Slings with single-rope legs, equalizing double-rope legs, or multiple-part rope legs.

Smooth coil strand - Strand composed entirely of round wires.

Snatch block - A single- or double-sheave block arranged so one or both cheek plates can be opened, permitting the block to be reeved without having to use a free rope end; also called gate block.

Socket - Type of wire rope fitting. See bridge sockets, closed sockets, open sockets, and wedge sockets.

Softeners - Anything used to protect the load or the rigging from damage while making a lift. Also, prevents load from slipping.

Splicing - Interweaving of two ends of ropes to make a continuous or endless length without appreciably increasing the diameter. Also, making a loop or eye in the end or a rope by tucking the ends of the strands.

Spooling (rope) - Winding of rope on a cylindrical drum in evenly spaced, uniform layers.

Spreader bar - A frame, forming part of the boom suspension, supporting sheaves for the live suspension ropes and attached to the fixed suspension ropes (pendants); also called bridle, spreader, live spreader, or floating harness.

Spreader beam - A fixture made of rigid parts, such as pipe, wide-flange, I-beam, channel, plate, etc., to assist in rigging a load; also called lifting beam.

Stainless steel rope - Wire rope made of low-carbon corrosion-resistant steel.

Standing line - A fixed-length line that supports loads without being spooled on or off a drum; a line of which both ends are dead; also called stay rope or pendant.

Standing rope (pendant) - A supporting rope that maintains a constant distance between the points of attachment to the two components connected by the rope.

Stop - A member to physically limit the travel of a trolley or bridge. This member is rigidly attached to a fixed structure and normally does not have energy-absorbing ability.

Strand, wire rope - A plurality of round or shaped wires helically laid about an axis.

Strand laid endless sling - Mechanical joint - a wire rope sling made endless from one length of rope with the ends joined by one or more metallic fittings.

Strand laid grommet - Hand tucked - an endless wire rope sling made from one length of strand wrapped six times around a core formed by hand tucking the ends of the strand inside the six wraps.

Strand laid rope - A wire rope made with strands (usually six or eight) wrapped around a fibre core, wire strand core, or independent wire rope core (IWRC).

Swaged fittings - Fittings in which wire rope is inserted and attached by a cold‑forming method.

Tackle - Those pieces of rigging such as slings, spreader bars, chokers shackles, thimbles, eyebolts, rings, or other handling fixtures used for attachment of the load to the crane or hoist.

Tagline - A length of rope used to guide a load that is being lifted into a desired position.

Taking up - The process of removing slack from a line or drawing (spooling) in on a line; loading a line by drawing in on it.

Test load - A load that is periodically applied to hoisting equipment to ensure that it can safely handle the rated capacity of the equipment. The test load is usually some percentage of the rated load capacity--100% to 150% of rated load.

Thimble - Grooved-metal fitting designed to prevent crushing or overstressing wire rope at the terminal end which is used to protect the eye of a wire rope or sling.

Tread diameter - The diameter of a sheave or grooved rope drum measured at the base of the groove. The diameter of a smooth barrel on a rope drum.

Trolley - A unit that travels on the bridge rails consisting of the frame, end trucks, drive supporting the hoisting mechanism, rope, and load block that supports the load, or a unit that travels on the lower flange of a beam or monorail system supporting a hoist.

Turnbuckle - Device attached to wire rope chain or rods for making limited adjustments in length, which consists of a barrel and right-hand and left-hand threaded bolts.

Warrington - A wire rope strand construction in which one layer of wires, usually the outer, is composed of alternating large and small wires.

Wedge socket - Wire rope fitting in which the rope end is secured by a wedge.

Winch head (gypsy head) - A rotatable cylindrical drum with curved end flanges, used for load handling by means of fibre rope coiled about its barrel with hand tension applied to the non-load end. Also called a capstan.

Wire rope - A plurality of strands of wire laid helically around an axis or a core.

Wrap - One circumferential turn of wire rope around a rope drum barrel.

Working load limit WLL - (see rated capacity).