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Elevator Safety and Licensing forms from the Texas Department of Licensing and Regulation office.

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Elevator Safety and Licensing reports from the Texas Department of Licensing and Regulation office.

Glossary of Terms

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A-C Terms



Safety Code for Elevators and Escalators as established by ASME (American Society of Mechanical Engineers). ASME was founded to promote the art, science & practice of multidisciplinary engineering and allied sciences around the globe. A17.1 covers the design, construction, operation, inspection, testing, maintenance, alteration, and repair of the following equipment, its associated parts, and its hoistways, where located in or adjacent to a building or structure: (a) hoisting and lowering mechanisms, equipped with a car or platform, which move between two or more landings. This equipment includes, but is not limited to, elevators; (b) power driven stairways and walkways for carrying persons between landings. This equipment includes, but is not limited to escalators and moving walks; (c) hoisting and lowering mechanisms equipped with a car which serves two or more landings and is restricted to the carrying of material by its limited size or limited access to the car. This equipment includes, but is not limited to, dumbwaiters and material lifts.


Americans with Disabilities Act. Ensures equal opportunity for persons with disabilities. Includes employment, State and local government services, public accommodations, commercial facilities, and transportation, and requiring the establishment of TDD/telephone relay services.

Alarm Bell

A bell operated by a push button in an elevator car. It is mounted either in a hoistway or adjacent to a landing where it may be heard at any time to call attention to the need for assistance in the elevator.


The American National Standards Institute (ANSI) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international standards so that American products can be used worldwide. For example, standards ensure that people who own cameras can find the film they need for that camera anywhere around the globe.

Arrival Gong

An Audible "Gong" noise to notify you when the car arrives.

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Arrival Light

A visual indicator light that notifies you when the car arrives.

Auto Lights

The cab lights can be wired to turn on only when the elevator is called and these will turn off by a timer.


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


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.


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


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


The side of an escalator extending above the steps. It includes skirt panels, interior panels, decks and handrails.


The bottom member of a sling for a hydraulic elevator.


Building Owners and Managers Association, an international professional association that provides information on office building development, leasing, building operating costs, energy consumption patterns, local and national building codes, legislation, occupancy statistics and technological developments. BOMA publishes standards for measuring office space, lobbies on behalf of the commercial real estate industry, and hosts conventions. The industry guidelines published by BOMA are referred to as "BOMA Standards."


The device used to attach the rails firmly to the hoistway.

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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.


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


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.


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.


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.


The surface within the cab, which is met by the closed gate, is known as the strike. The particular finish or color of wall material chosen by the designer could be stainless, brass or plastic laminate.


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


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.


That amount of the drive sheave actually in contact.


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


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

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


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


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.


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 operating.


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.


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


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.


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

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


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.


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. 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.


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.


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


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 electro mechanical relays or a computer to control the operation of an elevator.


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


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


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


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


The outermost lining of a hydraulic jack.

Cab Mounted master door operator

This motor-driven device is mounted on the car roof and will open the door at each landing but not the car gate. There would be an operator on each side of the car to operate opposite openings.

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D-F Terms



Direct Current (a source of power for an elevator machine).


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.


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


Devices at the bottom of horizontal sliding door panels swinging in and out.


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.

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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.


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


A motor-driven device mounted on the elevator car that opens and closes the car doors.


The device on the automatic door that senses an obstruction, (though contact may occur) and changes the door motion by either stopping it, or causing it to reverse.


A common roping arrangement on traction elevators. To increase the traction, the hoist ropes pass around a secondary sheave mounted beneath the main drive sheave and back over the drive sheave again.

Drive Chain Tensioning Device

Controls the correct tension of the drive chain.

Drive Machine

The power unit that applies the energy necessary to raise and lower any elevator, material lift, or dumbwaiter car or to drive an escalator, an inclined lift, or a moving walk.

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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.


Means to move the elevator (hydraulic, hydraulic & cable, cable, and cable with counterweights.)


The cylinder of a drum type-hoisting machine in which the elevator car hoist ropes and drum counterweight ropes wind and unwind to raise and lower the car and counterweight.

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.


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


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.


A hoisting or lowering mechanism, designed to carry passengers or authorized personnel, equipped with a car or platform, which moves in fixed guides and serves two or more landings. On average, an elevator travels 4-5 floors, or 40 feet and carries an average of five people per trip.

Emergency Exit

An opening at the top of an elevator for maintenance and emergency personnel. The top-emergency-exit can be opened only from the top of the car.

Elevator 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 and can stop a fully loaded elevator.


A power-driven, inclined, continuous stairway used for raising or lowering passengers.

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The decorative cover which houses control devices such as position indicators, push buttons, key switches, etc.

Finished size

The hoistway size AFTER completed finishing (drywall or wall covering).

Fault Finder

A display that indicates elevator functions and malfunctions.


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.


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.


Feet per minute.

Freight Elevator

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

Full Speed

A display that indicates elevator functions and malfunctions.

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G-I Terms


Gal N

The N type door lock has four electrical switches within it known as contacts, made by the GAL Corporation in NY. Typically this lock is used in combination with a retiring cam.

Galvanized Steel

plain carbon steel that has been Electro-plated with a zinc alloy to create a "rust-proofing" barrier on the base metal.(bright silver with speckled appearance)

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.


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.


An electro mechanical device that converts mechanical energy to electrical energy (usually direct current).


(1) 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 overspeeds in the up direction. (2) On escalators, a direct-driven centrifugal device which, when activated by overspeed, cuts off power to the drive motor and service brake.

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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.


"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.


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

(1) 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. (2) Guiding projections mounted on the bottom edge of horizontally sliding doors or gates, or on the sides of vertically sliding doors or gates to guide them.

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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.


(1) The moving handhold provided for escalator passengers, which moves over the top of the balustrade and newels. (2) 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.

HELP Button

A device, found on modern elevators in place of alarm button, used for emergency communications. When pressed, it shall initiate a call for assistance and establish two-way communications.

Hitch Plate

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

Hoist Cables

The high strength, flexible woven steel wires that suspend the car with rated load and possibly counter weights.

Hoist Rope

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

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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.


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.

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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.


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 electro-mechanical 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.

Individual power door operator

This motor device is at each door on every landing to open that particular door but not the car gate.


This takes place by a local elevator inspector to verify that an elevator or dumbwaiter is in compliance with standard codes applicable to that device.

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J-L Terms



The device which pushes the hydraulic elevator.


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


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.


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.


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.


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

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M-O Terms


Magnetic landing system

An Electro-magnetic device which moves with the car along a thin steel tape for the purpose of informing the controller about the car location in the hoistway. It also automatically re-levels the car if it moves up or down from floor level.

Machine-Room-Less (MRL) Elevator

A type of elevator where a separate machine room is not provided. The driving machine is typically located within the hoistway.


A plastic like material giving appearance of deep rich paint; very durable and hard, bonded to both sides of Particleboard.

Metal flush swing entrance

This is the door through which the passengers gain access to the elevator from the building. Being metal gives the advantage of having the proper fire rating and the flush fit of the frame to the hoistway inside wall gives the correct running clearance.

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.

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Net Travel 

The distance from the top to the bottom floor.


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.


Number of openings in the cab (car). The clear passageway into an elevator.

Over speed governor

This device actuates the safety by sensing that the car is traveling too fast downward.

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.

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.

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P-R Terms


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.


A feature incorporated into the signal system of an elevator or elevators by which an 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.


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


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.


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.


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

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

PlC (Programmable logic controller)

A control device that uses a programmable microprocessor and is typically programmed IIEC 61131 programming languages. The number of I/O ports they provide often categorizes PLC. This device controls the motion of the elevator based on the call of the passenger.


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 Gate Operator

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

Power Unit

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

Pressure switch

This electrical/hydraulic device is attached to the control valve to scene when there is low pressure in the oil line and prevents the car from being operated.

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.


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.

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Relay Controller

A relay is an electromagnetic switch used to control multiple circuits on the elevator. There is many of these type switches in a typical controller.

Retiring cam

This electrical/mechanical device is used to activate the door locks when the elevator is at floor level and it will retract when the elevator is moving between floors.

Roller Guides

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

Rail Clips

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


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.


The operation of reducing the elevator drive motor speed from normal operating speed to stop. Also referred to as Deceleration.

Revolutions Per Minute (RPM)

The number of completed turns per minute that an object revolves around its axis.


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


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.


The rotating element of an AC induction motor.

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S-U Terms


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.


A mechanical device attached to the elevator car or to the counterweight to stop and hold the car or counterweight under one or more of the following conditions: predetermined overspeed, free fall, or if the suspension ropes slacken.

Safety Astragal

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

Safety Plank

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


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.

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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.


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


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.


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, front-to-back.


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.

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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.


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.


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


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 than 200 feet per minute, which cushions the elevator. It is located in the elevator pit.


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


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


The moving platform on which an escalator passenger rides.


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


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.

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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.


(1) A force that produces or tends to produce rotation or torsion. 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.


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.

Travel distance

The distance from lowest landing to highest upper landing.

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Travel Restrictor

Limits the travel distance in hoistway and allows the unit to be worked on without endangering the person repairing the unit.

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.

V-Z Terms


Variable Voltage

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


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.


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

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