Glossary of Terms

Arbor: A carriage or rack that contains counterweights, usually flame cut steel or cast iron, in sufficient quantity to balance a load. Usually guided with Tee or Jay track, or with wire guides. An arbor is one component of a lineset.

Batten: A bar, usually made from steel pipe, from which scenery, lights and curtains are hung. A batten is one component of a lineset.

Block: A pulley. Typically a sheave (designed either for cable or fiber rope) between two cheek plates which can be mounted to supporting steel.

Brail Curtain: A curtain that is raised (opened) with brail type liftlines and is sewn flat or has horizontal fullness.

Clew: Device that connects several ropes or cables to one, usually stronger, rope or cable.

Counterweight: (n) Weights, usually flame cut steel or cast iron, that are placed in arbors to balance the weight of loads hung on battens. (v) The act of adding or removing weight from a lineset in order to achieve a balanced system.

Counterweight Assist Winch: An electric winch whose capacity is augmented by the addition of a counterweight arbor.

Dead Hung: An element that is hung statically over the stage or house, and which does not travel.

Double Purchase: A system that 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. Generic name for a rigging system that employs a two‐to‐one mechanical advantage.

Drum Winch: A winch with a drum for wrapping up cable as it is taken up.

Fire Safety Curtain: A curtain made of flame‐resistant material that closes automatically in event of a fire to prevent heat, smoke and flames on the stage from reaching the audience.

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 such as loftblocks and headblocks and access to that equipment for inspection and maintenance.

Headblock: A pulley mounted to support steel that changes the direction of liftlines and operating lines between the loftblocks and an arbor or winch.

Hemp Rigging: A rigging system that employs ropes (especially natural‐fiber rope) and sandbags instead of counterweight arbor or, winches. Usually used for temporary rigging.

Hemp Rope: Natural fiber rope used for Hemp Rigging

House: The seating part of an auditorium

Jay Track: “J” shaped aluminum members placed in parallel rows to guide arbors or clews. The rigging wall of a counterweight system is often called a “Jay Bar Wall”.

Liftline: In a line set, the steel cable that connects to the batten at one end, and to the arbor or winch drum at the other.

Lineset: The basic unit of a counterweight rigging system. A line set consists of a batten, liftlines, loftblocks, a headblock, and a counterweight arbor.

Line Shaft Winch: A winch with a series of cable drums connected to a gearbox by a common shaft.

Loading Gallery (Loading Bridge): A gallery above the stage floor where technicians add and remove counterweights from the arbors. Usually located high on the rigging wall so that technicians have access to arbors when battens are at their lowest positions.

Loftblock: A pulley mounted to the gridiron or support steel that supports and changes the direction of a liftline cable between the batten and the headblock.

Proscenium: The dividing wall or barrier between audience and the stage.

Single Purchase: A rope or cable passing from a lifting device (arbor, winch, or person) over a block, or series of blocks, directly to a load. Force must be exerted equal to the load to be held or raised. This is a generic term for a counterweight system that does not employ a mechanical advantage.

Stage: A platform on which performances are given.

Straight Lift Curtain (Guillotine): A curtain that can be raised (opened) without folding in any way.

Tee Track: “T” shaped steel members placed in parallel rows to guide arbors or clews. The rigging wall of a counterweight system is often called a “Tee Bar Wall”.

Travel: The path of moving stage equipment and the distance moved.

Walking Grid: (see Wire Grid)

Winch: a machine used for pulling or lifting. Often used in place of a counterweight arbor in a lineset.

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. Also, a generic term for a counterweight rigging system that uses wire guided arbors.

Zero Fleet Angle Hoist: A hoist with cables that exit the winch at fixed points so that fleet angles do not need to be considered in the rigging layout. This is accomplished by incorporating a moving head block or by making the drum move in relation to the head block