Unit 4 - Escalator Technology

Questions and Answers

What component is responsible for moving the handrail along the tracking system?

Newel

Handrail Drive (correct)

Bull Gear

Handrail Idler Sheave

Which part of the escalator assists in reversing the direction of the handrail?

Handrail Base

Handrail Drive Sheave

Idler Sheave (correct)

Handrail Drive Chain

Which component helps to maintain the support and alignment of the handrail during operation?

Handrail Support Rollers (correct)

Handrail Idler Sheave

Bull Gear Shaft

Handrail Drive

What is the primary function of the handrail Drive Chain Sprockets?

Linking the bull gear to the handrail drive sheave Signup and view all the answers

What type of motion does the handrail drive create for the handrail?

Linear motion Signup and view all the answers

What are the two main types of handrails in escalator technology?

Standard and Vee-type Signup and view all the answers

Which handrail drive system utilizes a friction-based mechanism?

Friction sheave drive Signup and view all the answers

Which component in the escalator is primarily responsible for driving the handrail?

Drive roller Signup and view all the answers

In the context of handrail systems, what does the term 'tensioner' refer to?

A component that maintains handrail tension Signup and view all the answers

What role does the guide element play in the functioning of a handrail?

Interacts with the handrail for correct movement Signup and view all the answers

Which of the following components is part of the friction sheave drive system?

Main drive sprocket Signup and view all the answers

What is a common characteristic of the standard handrail compared to the Vee-type?

Different interaction with drive elements Signup and view all the answers

Which mechanism assists in maintaining tension in the handrail drive chain?

Handrail take-up device Signup and view all the answers

What is the speed tolerance for the handrail in relation to the speed of the escalator steps?

0% to 2% Signup and view all the answers

How do handrails receive their motion according to the specifications?

From the escalator's main drive via direct gearing Signup and view all the answers

What feature is specifically required to maintain handrail tension?

Tensioning devices Signup and view all the answers

What design consideration is highlighted for the handrail's return into the newel?

Inconspicuous and difficult to reach Signup and view all the answers

What is an unacceptable practice regarding the handrail?

Pre-tensioning of the handrail Signup and view all the answers

What type of bearings are required for handrail rollers?

Sealed bearings rated for 100,000 hours Signup and view all the answers

To prevent lubricant contamination, friction drive sheaves and idlers must be designed so that:

Lubricant cannot reach the handrail surface Signup and view all the answers

How is the handrail pulled along its track?

By a series of pulleys connected to a chain Signup and view all the answers

What is the primary function of the handrail on an escalator?

To provide a hand-hold for safety while using the escalator Signup and view all the answers

How does the handrail take-up device function in an escalator system?

It removes slack in the handrail to ensure proper tension Signup and view all the answers

What materials are used in the construction of the escalator handrail?

Laminated rubber, canvas, and a stainless steel cord centre Signup and view all the answers

What role do the pressure rollers play in the escalator handrail system?

To apply pressure to the handrail ensuring sufficient contact Signup and view all the answers

Where are the guide rollers positioned in the escalator handrail system?

Adjacent to the drive wheel on both the uphill and downhill sides Signup and view all the answers

What two sides does the drive wheel of the escalator have?

Uphill and downhill Signup and view all the answers

What purpose does the formed steel guide serve in the escalator system?

To guide the handrail over rollers at newel ends and upper curve section Signup and view all the answers

What is the function of the nips formed by the pressure rollers in the escalator system?

To create a gripping point for the handrail against the drive wheel Signup and view all the answers

What is the primary function of the handrail drive chain?

To connect the drive sprockets with the handrail drive sheave Signup and view all the answers

Where are the handrail take-up devices located?

Directly downhill from the handrail drive sheaves Signup and view all the answers

What is the purpose of the adjustable take-up sprocket in the handrail drive chain system?

To maintain the necessary slack in the handrail drive chain Signup and view all the answers

What does the handrail take-up device utilize to adjust slack in the handrail?

A combination of short and long devices Signup and view all the answers

How do handrail support rollers contribute to the escalator's operation?

By maintaining proper tension throughout the handrail Signup and view all the answers

What mechanism ensures that the handrail is driven properly?

The right amount of slack in the handrail Signup and view all the answers

Why is the long handrail take-up device significantly important?

It can pivot for better adjustment and slack removal Signup and view all the answers

What type of lubrication system is used for the handrail drive chain?

Enclosed bath lubrication system Signup and view all the answers

Study Notes

Handrail Overview

Handrails are installed atop each escalator balustrade, moving at the same speed as the steps with a tolerance of 0% to 2%.
Motion is delivered via direct gearing from the escalator's main drive, ensuring synchronized movement in both directions.
Handrail design includes a V-shaped wedge for proper engagement with guiding wheels, preventing disengagement during operation.

Newel and Safety Features

Newels are constructed to return handrails inconspicuously and are equipped with upper and lower sheaves.
Handrails, drive systems, and guides are designed to avoid being thrown off while running.
Handrail rollers feature sealed bearings rated for 100,000 hours with built-in lubrication retention.

Handrail Types

Two primary handrail types: Standard and Vee-type, each reliant on interaction with escalator guide elements.
Standard handrails provide steady contact, while Vee-type handrails are designed for enhanced guidance.

Handrail Drive Systems

Common handrail drive systems include:
- Driving roller drive accompanied by tensioning mechanisms.
- Traction pulley or friction sheave drive, which utilizes drive wheels and pressure rollers for movement.

Handrail Composition and Function

Handrails consist of continuous vulcanized belts made of laminated rubber, canvas, and center stainless steel cords, serving as safety aids during escalator use.
Movement involves pressure rollers forming nips with drive wheels, ensuring adequate contact and smooth transitions around drive wheels.

Handrail Drive Components

Handrail Drive and Idler Sheaves: V-grooved sheaves located at upper and lower newels manage handrail movement and direction reversal.
Handrail Drive Chain Sprockets: Connects directly to the bull gear shaft, facilitating power transfer to the handrail drive sheave.
Handrail Drive Chains: Double-stranded chains serving as mechanical links, equipped with lubrication systems for maintenance.

Handrail Take-Up System

Adequate traction relies on correct slack levels in the handrail, managed by devices designed to take up excess slack.
Handrail Take-Up Devices: Positioned downhill from drive sheaves and adjustable for both short and long configurations.
Handrail Support Rollers: Installed at various points along the incline for steady handrail support and alignment.

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Description

This quiz covers specifications and mechanics related to escalator handrails. It includes details about their movement, speed tolerance, and connection to the escalator drive system. Understanding these components is crucial for those working in escalator design and maintenance.

Unit 4 - Escalator Technology - Handrail