Glossary of Terms

Essential Information About Elevator Systems



AC - Alternating Current (a type of power for an elevator machine).

Acceleration - A period which the elevator moves at an ever increasing rate of speed, usually referring to that period from standstill to full speed.

AC System - A control system for an AC motor which has a single synchronous speed or two different synchronous speeds.

ADA (Americans with Disabilities Act) - The Americans with Disabilities Act of 1990 was signed into law by President Bush on July 26, 1990. The ADA is designed to give civil rights protection to people with disabilities, similar to those granted by the Civil Rights Act.


Babbitt - A soft metal used to fill scratching of a plunger surface. It is also used to secure hoist ropes to shackles.

Baked Enamel - An enamel paint that must be baked to adhere to the surface.

Bolster - The bottom member of a sling for a hydraulic elevator.

Brace Rod - Supports for the outer corners of the platform, each of which tie to upper portions of the stile.

Brackets (Guide Rail) - The device used to attach the rails firmly to the hoistway.

Brake - An electro-mechanical device used to prevent the elevator from moving when the car is at rest and no power is applied to the hoist motor. On some types of control, it also stops the elevator when power is removed from the hoist motor with a spring-loaded clamping device that holds the elevator car when the machine is turned off.

Brake Drum - A round, machined surface on the motor shaft, which the brake clamps.

Brake shoe - Moving member(s) of a brake, lined with friction material which, when in contact with the brake drum, holds the elevator at floor level. On some types of control, it will stop the elevator when power is removed from the hoist motor.

Brush - A device, usually of carbon or graphite composition, used to connect a circuit with the rotating or moving portion of a DC motor, generator or other electrical device. It carries current to and from the non-moving parts of connections.
Buffer - A device designed to stop a descending car or counterweight beyond its normal limit of travel by storing or by absorbing and dissipating the kinetic energy of the car or counterweight.


Cab - The decorative room in which people ride in a passenger elevator.

Cable (Rope) - Usually 4 to 6 in number, it is used to support the car and (passing over the drive sheave to the counterweight) pull the car.

Cable Wrap - That amount of the drive sheave actually in contact

Callback - In contract elevator service, a customer request which requires a check of an elevator other than the regularly scheduled maintenance.

Call Cancellation - The circuitry that clears a registered call using selector switching, hoistway switches, or moveable brushes or contacts.

Capacity - Indicates the amount of weight a given elevator is able to support safely.

Car (elevator) - The load-carrying unit, including its platform, frame, enclosure, and car door or gate.

Car Counterweight - A set of weights roped directly to the elevator car of a winding-drum type installation. In practice, this weight is equal to approximately 70 percent of the car weight.

Car Operating Station - A panel mounted in the car containing the car operating controls, such as call register buttons, door open and close, alarm emergency stop and whatever other buttons or key switches are required for operation.

Car Riding Lantern - A fixture mounted in either the entry column, soffit or back wall which shows the direction of car travel.

Car Top Inspection Station - A control panel on top of an elevator car which, when activated, removes the car from normal service and allows the car to run at inspection speed from the car top station only.

Center Opening Doors - A door type, which consists of two horizontal sliding panels, which move in opposite directions.

Clutch - A device used in elevator power door operation to engage the car door to the landing door by a grasping and holding movement.

Code - A system of regulations pertaining to the design, manufacture, installation and maintenance of elevators, dumbwaiters, escalators and moving walks. The most widely recognized and used is ANSI A-17.1 sponsored by the National Bureau of Standards, The American Institute of Architects, The American Society of Mechanical Engineers, and published by ASME. It has been adopted by many states. Some states and cities have written their own codes, most of which are based on the ANSI A-17.1. In California, the governing code is Title 8
and 24.

Compensating Chain - A welded-link chain used for hoist rope weight compensation.
One end of the chain is attached to the underside of the elevator car, and the other end is fastened to the counterweight or stationary fastening in the hoistway.

Compounding Sheave - A pulley located on the car, and on the counterweight, under which the hoist cables run to double the capacity and reduce the speed of an elevator.

Control Valve - The device, which, on hydraulic elevators, controls the oil flow to and from the jack.

Controller - A device, or group of devices, which serves to control, in a predetermined manner, the apparatus to which it is connected. An electrical panel, which uses electromechanical relays or a computer to control the operation of an elevator.

Conventional Car Station - A car-operating panel with a faceplate that is mounted in a fixed (non-swing) panel or sidewall.

Corner Post - A method of mounting rails in opposite corners of the hoistway, usually to accommodate doors in adjacent hoistway walls.

Counterweight - A weight which counterbalances the weight of an elevator car plus approximately 40% of the capacity load.

Crosshead - (1) The upper member of the car frame. (2) The traveling member of a selector.

Cylinder - The outermost lining of a hydraulic jack.


Deceleration - A period during which the elevator moves at an ever decreasing rate of speed, usually referring to that period from full speed to leveling speed.

Deflector Sheave - A pulley, aligned with the drive sheave, which provides a path for the cables to drop straight to the counterweight.

Direct Current (DC) - An electric current flowing in one direction only and substantially constant in value.

Dispatch Control System - A system that controls two or more elevators by governing assignments in response to hall calls. Also controls zoning, peak traffic demands and parking.

Door Gibs - Devices at the bottom of horizontal sliding door panels, which stick into sill grooves and eliminate door panels swinging in or out.

Door Hanger - A rolling assembly fastened to the top of a door panel which supports and allows horizontal sliding movement of the door panel. The door track on which the hanger rolls is part of the door hanger assembly.

Door Lock - Any type of mechanical lock designed to prevent the opening of a hoistway door from the landing side.

Door Open Time - Length of time doors stand open after reaching full open position,
until doors start to close provided no signal is received to shorten door time.

Door Operator - A motor-driven device mounted on the car which opens and closes
the car doors.

Door Panel - A portion of the door or gate, which covers the opening and moves to uncover the opening.

Door Protective Device - Any type of device used with automatic power operated doors that detects obstructions to the normal closing of the elevator doors and either causes the doors to reopen or go into some other mode of operation, such as nudging. A safe edge, a safety astragal, a photoelectric device (safe ray), and electrostatic field device are examples of door protective devices.

Door Sill - The threshold of a door opening with grooves to guide the bottom of the car door.

Door Track - A rail which accepts the rolling assembly of the door hanger and allows the horizontal movement required to open and close the doors. The door track is a part of the door hanger assembly.

Drip Ring - A flange on the guide used to collect oil from the plunger so it can drain into a container.

Drive - The pulley or wheel, grooved for each hoist cable, which drives the elevator up or down.

Drive Machine - The power unit which applies the energy necessary to raise and lower an elevator, material lift, or dumb waiter car or to drive an escalator, an inclined lift or a moving walk.

Drive Sheave - The grooved wheel of a traction-type hoisting machine over which the hoist ropes pass, and by which motion is imparted to the car and counterweight by the hoist ropes.


Electric Eye - A light beam (or beams), which spans a door opening and, when interrupted, causes the door to reopen.

Emergency Stop Switch - A hand-operated switch in the car push button station which, when thrown to the off position, stops the elevator and prohibits its running.

Enclosure - The ruggedly built room on a freight elevator in which the material being carried is located.

Encoder - A device used to convert an analog signal into digital information.

End Post - A method of mounting the two stacks of rails on a common wall at the end of the hoistway.


Faceplate - The decorative cover which houses control devices such as position indicators, pushbuttons, key switches, etc.

Feedback - The transmission of current or voltage from the output of a circuit or device back to the input, where it interacts with the input signal to modify the operation of the circuit
or device.

Firefighter's Service - A device or group of devices which provide (1) a signal for immediate recall to a designated landing in order to remove cars from normal use, and (2) to permit special operation for firefighters or other authorized emergency personnel.

Fishplate - A steel plate, which spans the joint where two lengths of guide rails in a stack meet.

Floor Selector - A mechanical, electrical, or microprocessor driven device which initiates and/or controls some or all of these functions: establish direction of travel, acceleration, deceleration, leveling, stopping, call cancellation, door operation, position indicators, and hall lanterns for an individual elevator.

FPM - Feet per minute.

Freight Elevator - An elevator used to carry material rather than people and provided with vertical bi-parting doors.

Full Speed - The contract speed at which the elevator should run.


Gates (Double Blade Gate) - A vertical sliding, counterweighted device used to provide entrance protection on freight elevators. It consists of two panels usually made of expanded metal. The blades telescope to reduce overhead space requirements.

Gear - A toothed wheel designed to mesh or engage with another wheel or part for transmitting or changing motion.

Geared Traction Machine - A traction machine in which the power from the motor is transmitted to the drive sheave through reduction gears.

Gearless Traction Machine - A type of elevator hoisting machine on which the hoist ropes pass over a traction drive sheave, which is an integral part of the armature. Called gearless because no geared reduction unit is utilized.

Generator - An electromechanical device that converts mechanical energy to electrical energy (usually direct current).

Governor - A mechanical speed control mechanism. For elevator, it is a wire rope driven centrifugal device used to stop and hold the movement of its driving rope. This initiates the activation of the car safety device. It opens a switch, which cuts off power to the drive motor and brake if the car travels at a preset overspeed in the down direction. Some types of governors will also open the governor switch and cut off power to the drive motor and brake if the car over speeds in the up direction.

Governor Rope - A wire rope attached to an elevator car frame that drives the governor and, when stopped by the governor, initiates setting of the car safety.

Groove - "Vee" - A groove in the drive sheave which produces a pinching or wedging effect on the cable, used on gearless machines. "U" - A groove in the drive sheave, which relies on friction between groove and cable, used on gearless machines.

Group Supervisory Control System - A system that controls two or more elevators by governing assignments in response to hall calls. Also controls zoning, peak traffic demands and parking.

Guide - An assembly, bolted to the upper end of the cylinder, which centers the plunger in the cylinder.

Guide Rails - Steel T-, round, or formed sections with guiding surfaces installed vertically in a hoistway to guide and direct the course of travel of an elevator car and elevator counterweights.

Guide Shoes - Devices used mainly to guide the car and counterweight along the path of the guide rails. They also assure that the lateral motion of the car and counterweight is kept at
a minimum as they travel along the guide rails.


Hall Call - A call registered at a landing button or fixture.

Hall Lantern - A corridor mounted signal light indicating that an elevator car is approaching that landing and the direction in which the car is to travel.

Hall Station - Device located in hall usually near the elevator to be used when calling the elevator to that floor.

Handrail - A railing serving as a support.

Handrail Guard - A guard, usually made of rubber, that fits over the outside of the handrail at a point where the handrail enters or leaves the balustrade. It is designed to keep a person's fingers out of the handrail opening.

Hanger Rollers - Rollers (two per panel) from which horizontal door panels are suspended.

Hitch Plate - A plate (on traction elevators) clamped to the underside of the crosshead and to which the shackles are attached.

Hoist Rope - The wire ropes used to raise and lower an elevator car.

Hoistway - The space enclosed by fireproof walls and elevator doors for the travel of one or more elevators, dumbwaiters or material lifts. It includes the pit and terminates at the underside of the overhead machinery space floor or grating, or at the underside of the roof where the hoistway does not penetrate the roof. (Hoistway is sometimes called "hatchway" or "hatch".)

Hoistway Enclosure - The fixed structure, consisting of vertical walls or partitions,
which isolates the hoistway from all other areas or from an adjacent hoistway, and in which the hoistway doors and door assemblies are installed.

Hydraulic - One of two methods by which an elevator is moved, whereby the elevator is "pushed" up by oil.

Hydraulic Elevator - A power elevator where the energy is applied, by means of a liquid under pressure, in a cylinder equipped with a plunger or piston.

Hydraulic Valve - In the construction of hydraulic elevators, a valve used to regulate the flow of the fluid used to raise and lower the elevator, usually a low viscosity oil.


Induction Motor - An AC motor having two parts: a rotor and a stator. The stator creates a rotating magnetic field, that induces a voltage into the rotor causing it to rotate.

Interlock - A device having two related and interdependent functions which are:
(1) to prevent the operation of the driving machine by the normal operating device unless the hoistway door is locked in the closed position. An electromechanical device that prevents operation of an elevator unless the hoistway doors are in the closed and locked position; (2) to prevent opening of a hoistway door from the landing side unless the elevator is in the landing zone and is either stopped or being stopped.

Intermediate Landing - Any landing served by an elevator between its upper and lower terminal landings.


Jack - The device which pushes the hydraulic elevator.

Jamb - Any one of the three members constituting an elevator entrance frame: head jamb, strike jamb and return jamb.


Landing - That portion of a floor, balcony, or platform used to receive and discharge passengers or freight.

Landing Door - The movable door at the entrance of an elevator which provides access to the hoistway.

Landing Zone - A zone extending from a point 18” below an elevator or material lift landing,
to a point 18” above the landing.

Layout - A scaled mechanical drawing showing dimensioned plan views and elevations of an elevator hoistway and machine room to indicate space conditions, pertinent dimensions, sizes and location of components of the installation.

Leveling - The movement of an elevator toward the landing sill when it is within the leveling zone. When the word leveling is used, the inference is that the process of attaining a level stop or position (the platform level with the landing sill) is performed completely automatically.

Leveling Zone - The limited distance above or below an elevator or material lift landing within which the leveling device is permitted to cause movement of the car toward the landing.

Lubricator - A device, which feeds oil to the rail and provides lubrication for sliding shoes.


Machine Room - The space in which the driving machine for an elevator or group of elevators, dumbwaiter, escalator or group of escalators is located.

Main (Car) Guide Rails - Steel T-sections with machined guarding surfaces installed vertically in a hoistway to guide and direct the course of travel of an elevator car.

Motor Control - That portion of a control system that governs the acceleration, speed, retardation, and stopping of the moving elevator.


Net Travel - The distance from the top to the bottom floor.

Nudging - A system used with automatic door operation which, if the door is held open by the door protective devices or the door open button for more than a predetermined time, will sound a warning signal and close the doors at a reduced speed and torque.


Oil Buffer - One type of buffer (for elevators with speeds of more than 200 feet per minute), which uses a combination of oil and spring to cushion the elevator. It is located in the elevator pit.

Oil Line - The pipe that channels the oil from the power unit to the jack.

Opening - The clear passageway into an elevator

Over Travel - A short distance beyond the terminal floor as allowance for building inaccuracies, manufacturing or installation inaccuracies.

Overspeed Governor Switch - A part of an escalator machine. It is actuated by centrifugal force and trips a switch when the motor speed has increased 20 percent over its rated nameplate speed.


Packing Gland - (1) The substance, usually of elastic or flexible material formed in rings used in the stuffing box of the worm shaft of a geared machine or of a hydraulic elevator to prevent excessive leakage. (2) Strips or blocks of material used for shimming.

Parking - A feature incorporated into the signal system of an elevator or elevators by which and elevator receives a signal to always return to a preselected landing after all its car or landing signals have been answered and canceled.

Passenger Elevator - An elevator used to carry people and provided with horizontal sliding doors.

Peak - In a waveform or other changing parameter, a peak is an instantaneous or local maximum or minimum.

Penthouse - The machine room above the hoistway on traction elevators.

Pickup Rollers - Devices on the hoistway door which mate with the clutch on the car door to allow the hoistway doors to be pulled open and closed.

Pit - That portion of the hoistway extending from the sill level of the lowest landing to the floor at the bottom of the hoistway.

Pit Channels - Steel channels on the pit floor to anchor the guide rails and other pit-mounted devices.

Platen - A plate, used to attach the jack to the bolster.

Platform - The entire floor assembly of an elevator on which passengers stand or the load is carried.

Plunger - The inside moveable part of a hydraulic jack that attaches to an elevator car frame on direct drive application or drive sheave on a cabled hydraulic system.

Position Indicator - A device that indicates the position of the elevator car in the hoistway.
It is called a hall position indicator when placed at a landing, or car position indicator when placed in the car.

Power Unit - That device on hydraulic elevators which supplies the motive force to run the car.

Preventative Maintenance - Inspections, tests, adjustments, cleaning and similar activities carried out on elevator and escalator equipment with the intention of preventing malfunctions from occurring during operation. It is designed to keep equipment in proper operating order and is done on a scheduled basis. It is also referred to as scheduled maintenance.

Pump - That device which draws oil from the tank and pushes it through the oil line to the jack to move the elevator up.

Push Button Station - A decorative device containing one or more hand-operated devices (buttons or switches) by which the passenger tells the controller what action is desired.


Rail Clips - Devices bolted to guide rail brackets to clamp rails firmly in place.

Relay - An electric device that is designed to interpret input conditions in a prescribed manner and after specified conditions are met, to respond and cause contact operation or create change in associated electric control circuits.

Revolutions Per Minute (RPM) - The number of completed turns per minute that an object revolves around its axis.

Ring - A large gear, which is attached to the drive sheave.

Riser - A series of hall stations for an elevator or group of elevators

Roller Guides - Guide shoes which use rollers that rotate on guide rails rather than sliding on the rails.

Rotor - The rotating element of an AC induction motor.


Safe Edge - A mechanical door protective and automatic door reopening device, used with automatic power door operators. It is arranged so that in the event the door either approaches or meets an obstruction when closing, the safe edge will actuate an edge safety switch that will automatically cause the doors to stop and reopen. It is vertically mounted to extend from the bottom to the top of a horizontally sliding panel and projects forward of the leading edge of the panel.

Safe Ray - A photoelectric door protective and automatic door reopening device for automatic power door operators. It consists of a photoelectric receiving unit and light source device arranged to project a light ray across the elevator door entrance. The interruption of the light ray will cause the doors to remain open as long as the ray is interrupted, or cause the reversal and reopening of doors that are closing.

Safety - A large clamp that anchors the car to the building to keep the elevator from falling.

Safety Astragal - A resilient, non-crushing member installed on the bottom of the upper section of a bi-parting freight elevator hoistway door.

Safety Plank - The bottom member of a sling for a traction elevator, which contains the safety.

Seal - A device mounted on the guide to minimize oil escaping around the plunger.

Secondary Sheave - A pulley on a gearless machine which serves two purposes: (1) To allow each cable to second pass over the drive sheave and (2) To deflect the cable for a straight drop to the counterweight.

Selector - An electrical device, driven by the elevator, which simulates elevator movements.

Setting the Safety - The act of triggering the safety to stop the elevator from falling.

Shackle - Threaded rods to which the hoist cables are socketed and which bolt to the hitch plate and the counterweight.

Shaft - That part of a rotor that carries other rotating members and that is supported by bearings.

Sheave Groove A wheel mounted in bearings and having one or more grooves over which a rope or ropes may pass.

Shim - A piece of metal or other material used to fill out a space.

Side Post - The normal practice of mounting rails on opposite hoistway walls midways,

Sill - The bottom horizontal member of an entrance which provides the foundation and footing for the entrance frame. The sill extends the full width of the door travel.

Single Blade Gate - A vertical sliding, counterweighted device used to provide entrance protection on freight elevators and consisting of one panel, usually made of expanded metal.

Single Speed AC - A type of traction machine powered by an AC-driven motor of one fixed speed.

Single Speed Door - A type of door consisting of one horizontal sliding panel.

Sling - The basic structural frame, which consists of two stiles, a crosshead and a bolster or safety plant, which supports the platform and cab of an elevator.

Soffit - The top horizontal piece of the entrance, which is the underside of the transom.

Specifications - A detailed itemized description of the plans, materials, dimensions and all other requirements proposed for the installation of the equipment.

Spring Buffer - One type of buffer, for elevators with speeds less then 200 feet per minute, which cushions the elevator. It is located in the elevator pit.

Stack - An accurate, vertical line of rails located in the hoistway. "Stack" may also be used when referring to conduit and electric wiring.

Stator - The non-rotating part of the magnetic structure in an induction motor.

Step - The moving platform on which an escalator passenger rides.

Stile - The vertical member of the sling, one for each side.

Stopping - The action of final motion of the elevator from leveling speed to an accurate floor level.

Strike Column - Column located inside the car, which extends the full height of the elevator door opening. This is the column against which the sliding door closes.

Stuffing Box - The part of a machine or cylinder in which seals or packing is installed to prevent leakage.

Swing Return Panel - A car-operating panel that extends the full height of the car entrance.


Tachometer - A device which measures the revolutions per minute of a revolving shaft.
To tach means to measure speed with a tachometer.

Tank (Reservoir) - A container to store the oil used to move the elevator.

Thrust Bearing - A bearing designed to withstand an axial load placed on a shaft such as that imposed by a worm and worm gear.

Top-of-car Inspection Station - Controls on the top of the car used by an elevator constructor to operate the car at inspection speed. It provides a means of operating an elevator from on top of the car at slow speed during adjustment, inspection, maintenance and repair.

Torque - (1) A force that produces or tends to produce rotation or torsion. The pressure, measured in foot pounds, exerted by a rotating shaft. (2) The turning power of a motor. (3) The turning effort a brake is designed to stop.

Traction Machine - An electric machine in which the friction between the hoist ropes and the machine sheave is used to move the elevator car with the cable.

Traction - One of two methods by which the elevator is moved, whereby the elevator is "pulled" up by cables.

Traveling Cable - A cable made up of electric conductors, which provides electrical connection between an elevator or dumbwaiter car, or material lift, and a fixed outlet in the hoistway or machine room.

Two Speed AC - A type of traction machine powered by an AC-driven motor (actually 2 motors built into one), which has 2 distinct speeds.

Two Speed Door - A type of door consisting of two horizontal sliding panels, which move, in the same direction.


Variable Voltage - A method of controlling a DC-driven machine, which produces many different speeds.


Worm - A shaft on which a spiral groove is cut.

Worm Gear - The gear wheel which engages the revolving worm. The rotating motion of the worm is transmitted through the worm gear to the drive sheave.


Zoning - The procedure which involves parking designated elevators to serve a specified floor or group of floors.