Rigging Terms

Glossary of Rigging Terms

Act Curtain	A curtain (sometimes designed for a specific show) that is opened to signal the beginning of a performance. The Front Curtain is often used for this purpose.
Arbor	A carriage or rack that contains weights, usually flame cut steel or cast iron, in sufficient quantity to balance a load.
Audience	The area of the theater where visitors sit to view a performance.
Auditorium	A hall or seating area within the hall where the audience views a performance.
Austrian Curtain	A curtain that is raised (opened) with bailed lifting lines and is sewn with both vertical and horizontal fullness.
Batten	A bar, usually made from steel pipe, from which scenery, lights and curtains are hung.
Beam Clamp	A device from which a load is hung, attached to the flange of a steel beam without altering the beam in any way.
Belaying Pin	A wood or steel rod, inserted into a hole in a pin rail, that secures ropes attached to a load.
Border Curtain	A curtain used to define the top limit of the stage and to mask or hide lights and unused scenery and curtains.
Brail Curtain	A curtain that is raised (opened) with Brail type lift lines and is sewn flat or has horizontal fullness.
Brail Lines	Lifting lines that pass through a row of rings sewn to the back of the curtain and attach at the curtain bottom. The curtain folds up when the lines are pulled.
Cable Roller	A roller assembly designed to prevent moving cables from contacting any part of a building or adjacent rigging. Not intended to change cable direction or carry loads.
Capstan Winch	A winch, usually portable, with an un-grooved drum designed to assist in moving heavy loads. An operator wraps a rope around the drum and pulls to tighten the rope on the drum. Friction causes the rope to travel with the rotating drum.
Carriage	See "Arbor."
Clew	Device that connects several ropes or cables to one, usually stronger, rope or cable.
Compensating Line	A system of light and heavy chains or cables that balances lift line weight as it transfers from the batten to the arbor side of a moving counterweight set.
Contour Curtain	A Brail or Austrian curtain rigged so that each lift line may be operated separately to form different shaped openings.
Counterweight	(n) Weights, usually flame cut steel or cast iron, that are placed in counterweight arbors to balance the weight of loads hung on battens. (v) The act of adding or removing weight from a set in order to achieve a balanced system.
Cyclorama	(1) Curtain at the rear of the performance area used to represent the sky or distant areas. (2) Set of borders, legs, and drops used to define the limits of a performance area.
Dash Pot	An adjustable, hydraulic ram that smoothly slows and stops a moving object.
Dead End	The end of a rope or part of a device that is not active or load carrying.
Dead Haul	Pulling a load that is not counterbalanced.
Dead Load	The permanent or non-removable part of a system load (i.e. the weight of a batten versus the load hung from it).
Double Purchase	A rope or cable that passes from a lifting device (arbor, winch, or person) over a block, to a block attached to the load, and tied off at the previous block, is double purchased. The system allows twice as much load to be raised for a given effort, but the rope or cable must be pulled twice as far, so the total work done remains the same.
Down Stage	The area of the stage that is closest to the audience. See "Raked Stage."
Drum Winch	A winch with a drum for wrapping up cable as it is taken up.
Equal Pitch	All grooves on a sheave have the same pitch diameter regardless of the diameter of the cables or ropes.
Fire Safety Curtain	A curtain that closes automatically in event of a fire to prevent heat, smoke and flames on the stage from reaching the audience.
Fireline	Firelines are installed around the perimeter of a stage-proscenium arch to hold the fire safety curtain open. Firelines connect the curtain to all manual electrical and heat activated devices that release the safety curtain.
Fleet Angle	The angle formed between the centerline of a sheave or drum and another sheave or fixed point.
Floor Block	Pulley mounted at the floor to hold a rope or cable in position and to reverse its direction. Floor blocks meant for rope often incorporate a means of adjustment to accommodate changes in length due to loads or environmental conditions.
Fly	The act of lifting scenery, lights, and curtains.
Fly Gallery	A gallery or catwalk above the stage floor from which counterweight and hemp (rope) rigging is operated.
Fly Loft	The space between the roof and the performance area that is not visible to the audience.
Front Curtain (House Curtain)	A curtain used to define the stage location to the arriving audience. It is often the curtain closest to the audience and may also perform the function of an "Act Curtain."
Fullness	Additional fabric that is added to a curtain to be sewn into pleats. 100 percent fullness means that the curtain would be double its finished width before the pleats are made.
Gridiron (Grid)	An open floor, usually made from light steel channels or grating, that is located near the roof steel. It provides mounting locations for rigging equipment and access to that equipment for inspection and maintenance.
Guide	To control the movement of rigging devices by means of slides or rollers moving in tracks or on stretched cables.
Hand Line	A line, usually rope, that is pulled by hand to lift or control the movement of a load.
Head Block	A pulley mounted to support steel that changes the direction of lift and operating lines between the loft blocks and an arbor or winch.
Head Block Beams	Structural steel designed to support the head blocks and carry vertical and horizontal loads.
Hemp (Rope or Spotline) Rigging	A rigging system that employs ropes and sandbags instead of counterweight arbors or other devices. Usually used for temporary rigging.
House	See "Auditorium."
House Left/Right	The sides of an auditorium as seen by an audience member while facing the stage.
Idler	A pulley designed to support one or more cables but not to make direction changes.
Incremental Block	A multi-grooved pulley that supports and changes the direction of cables between the load and the head block and that supports other, more distant, lines in the set.
Index Light	A series of lamps in a special housing designed to illuminate the locking or pinrail area.
Lattice Track	A parallel pair of angles or other structural members that guide an arbor or clew. Low friction slides or roller guides are placed on both sides of the device to be guided.
Leg Curtain	A curtain used to define the side limit of the stage and to mask or hide actors, lights, and unused scenery in the off stage area (wings).
Lighting Bridge	A walkway across the stage (fixed or flown) where lights are hung and where they may be adjusted and maintained.
Line Shaft Winch	Winch with a series of cable drums connected to a gearbox by a common shaft.
Live End	The end of a rope or part of a device that is active or load carrying.
Live Load	That part of a system load that may be added or deleted (i.e. lights hung from a pipe batten).
Load Brake	A secondary brake that holds the full load in the system, usually in the case of a failure in the system.
Loading Gallery (Loading Bridge)	A gallery above the stage floor where technicians add and remove counterweights from the arbors. Usually located so technicians have access to arbors when battens are at their lowest positions.
Loading Rail	A structural railing designed to support rope locks in a way that allows them to be safely operated. It carries any out of balance loads from the rigging system held by rope locks.
Loft Block	A pulley mounted to the gridiron or support steel that supports and changes the direction of a lift line cable between the load and the head block.
Masking	A set of curtains or scenic elements used to define the visual limits of a performance area.
Mouse	To wrap the end of a rope, cable or turnbuckle to prevent it from unwinding.
Mule Block	A pulley that supports and changes the direction of one or more cables traveling between loft blocks and head block.
Multi-Sheave Block	A block which contains a number of sheaves and sets of bearings so that each rope or cable can operate independently.
Off Stage	The stage floor area that is not a part of the acting area and is not visible to the audience.
Olio Curtain	A curtain located between the "Front" or "Act" curtains and the "Rear" curtain that closes off a portion of the acting area for more intimate presentations. It is often colored or decorative.
On Stage	The portion of the stage area visible to the audience, usually defined by masking curtains, scenery, an orchestra shell, or by lighting.
Orchestra	(1) A group of musicians who play instrumental selections (2) The portion of the auditorium on the main floor that is closest to the musicians and the acting area.
Orchestra Lift	A moving platform that is used to adjust the elevation of the musicians in relation to the stage and auditorium. Usually operates within the confines of an orchestra pit.
Orchestra Pit	A depressed area between the stage and audience seating area where musicians sit, so the audience can hear the music and see the performance over the heads of the musicians.
Orchestra Shell	An enclosure on stage, consisting of walls and a ceiling that reflects sound into the auditorium. Usually decorative in nature.
Outrigger	A barrier device that protects counterweight arbors from scenery, etc. that may be leaned against them. Often also supports index lights.
Overspeed Brake	A secondary brake designed to halt a load if it exceeds a preset speed.
Pileup Winch	Winch with special drum that piles up cable in a single layer in a slot. Also called a "Yo-Yo" drum winch.
Pinrail	A railing with holes to accept belaying pins. May also act as a safety railing at the edge of a gallery or walkway.
Pipe Clamp	Clamping device that bolts around a pipe for attachment of chain or cable hangers.
Pipe Grid	Horizontal structure hung over a stage or auditorium to support lights and scenery. Made from pipes crossing on right angles at set intervals.
Pitch Diameter	Diameter of a sheave or drum measured from the center line of the cable wrapped around it.
Pivot Block	A pulley designed to adjust to structures at odd angles.
Portal	A portal consists of a header (border) and tabs (legs) that can be moved to adjust the size and shape of the proscenium opening to fit various performance needs. It is usually located just up stage of the front curtain and may have provision for mounting lights.
Proscenium	The dividing wall or barrier between audience and the stage.
Proscenium Arch	The opening in the proscenium through which the audience views a performance.
Raked Stage	A sloped platform that is lower near the audience for better visibility and higher at the rear, providing the illusion of distance. This is the source for the terms "Down Stage" and "Up Stage."
Rope Lock	A cam operated device that clamps the hand line that is attached to an arbor in order to prevent movement. Designed to hold the unbalanced load in a set.
Safety Chain	(1) A secondary support line, usually of chain, that supports a fire curtain or other device when the primary support cable become slack for any reason. (2) The extra weight of fire curtain safety chains helps the fire curtain accelerate at the start of its travel.
Sag Bar	A support rail, usually of wood or plastic, that keeps cables from sagging over a horizontal span due to their own weight. Sag bars don't carry any loads.
Sandbag	A fabric bag that can be filled with sand and attached to rope rigging as a counterbalance to the load hung from the set.
Scrim	A curtain made from a semitransparent material that looks solid when lit from the audience side and becomes almost invisible when back lit.
Self-Climbing	A pipe grid or batten that has an integral device for raising and lowering.
Set	A system of cables, pulleys, lifting devices and battens that holds a specific set of scenic elements, curtains or lights.
Sheave	A component with a groove around its circumference to support and contain a rope or cable and a bearing at its center to permit rotation about a shaft.
Single Purchase	A rope or cable passing from a lifting device (arbor, winch, or person) over a block, or series of blocks, to a load is single purchased. Force must be exerted equal to the load to be held or raised.
Slack Line	A cable that droops or leaves the sheave or drum groove because it lacks tension in the line.
Smoke Pocket	A slot, usually of fabricated steel that supports a guide system at the edges of a fire safety curtain and that helps to prevent smoke passing around the edges of the curtain.
Spotline Rigging	A temporary rigging system designed to be easily installed. Often rigged with rope instead of counterweight.
Stage	A platform on which performances are given.
Stage Left/Right	The left and right sides of a stage as seen by an actor standing on stage facing the audience.
Stage Lift	A portion of the stage floor that may be raised or lowered.
Straight Lift Curtain	A curtain that can be raised (opened) without folding in any way.
Swivel Block	A pulley that rotates in the horizontal plane
Tab	(1) A masking leg that is mounted at right angles to the front of the stage. (2) See "Portal."
Tag Line	A line attached to a load to assist in controlling its movement.
Tee Guides	"T" shaped members placed in parallel rows to guide arbors or clews. Guides may consist of low friction slides or rollers.
Tieoff Bracket	A bracket attached to rigging blocks, gridiron, or other structure to hold wires for guiding clews.
Traction Drive Winch	Winch with a v-grooved drum that uses friction between cables and the sides of the grooves to engage the pulling cables. Increasing the cable tension causes the cables to jam tighter in the v-grooves.
Travel	The path of moving stage equipment and the distance moved.
Traveler	A curtain on a track that can be opened or closed to reveal or mask a portion of the stage.
Tread Pressure	The force exerted by a rope or cable against the bottom of a groove in a sheave or drum.
Trim	(1) A load is "in trim" when the equipment load equals the counterbalancing weight. (2) A set or element is trimmed when it has been placed in the desired position within the performance area.
Trim Chain	A length of chain placed between a lift line and a pipe batten or scenic element to connect them and to facilitate minor height adjustment of the load.
Tripped	A curtain or scenic element is lifted by a second set of lines attached at the bottom or intermediate point on the piece. Pulling the lines will cause the piece to fold in half or thirds. Note: If the piece is counterbalanced, the weight balance will shift as the piece is tripped.
Under Hung	Hung from the bottom of a beam or structure.
Up Stage	The portion of the stage that is furthest from the audience. See "Raked Stage."
Upright	Resting on top of a beam or structure.
Valance	See "Border." Usually a special border associated with the "Front Curtain." May be permanently fixed within the proscenium arch.
Wall Batten	Horizontal structural members to which guide tracks are attached.
Wall Knee	Bracket that attaches a wall batten to the building structure.
Well	An open slot in a gridiron, usually framed with upright channels, that supports loft blocks and permits cables to be dropped through the grid to a batten or other load.
Wings	The portion of the stage area located to either side of the acting area.
Wire Grid	An open floor that supports lights or provides access to theatrical equipment. It is formed of woven cables attached to, and supported by, a structural frame.
Wire Guide	Wires placed to control the location and travel of arbors, clews and curtains.
	*Courtesy of JR Clancy, Inc*

SAPSIS RIGGING INC • 233 N Lansdowne Ave • Lansdowne, PA • 19050 • 800-727-7471