Questions and Answers
What component is responsible for moving the handrail along the tracking system?
Which part of the escalator assists in reversing the direction of the handrail?
Which component helps to maintain the support and alignment of the handrail during operation?
What is the primary function of the handrail Drive Chain Sprockets?
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What type of motion does the handrail drive create for the handrail?
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What are the two main types of handrails in escalator technology?
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Which handrail drive system utilizes a friction-based mechanism?
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Which component in the escalator is primarily responsible for driving the handrail?
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In the context of handrail systems, what does the term 'tensioner' refer to?
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What role does the guide element play in the functioning of a handrail?
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Which of the following components is part of the friction sheave drive system?
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What is a common characteristic of the standard handrail compared to the Vee-type?
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Which mechanism assists in maintaining tension in the handrail drive chain?
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What is the speed tolerance for the handrail in relation to the speed of the escalator steps?
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How do handrails receive their motion according to the specifications?
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What feature is specifically required to maintain handrail tension?
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What design consideration is highlighted for the handrail's return into the newel?
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What is an unacceptable practice regarding the handrail?
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What type of bearings are required for handrail rollers?
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To prevent lubricant contamination, friction drive sheaves and idlers must be designed so that:
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How is the handrail pulled along its track?
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What is the primary function of the handrail on an escalator?
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How does the handrail take-up device function in an escalator system?
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What materials are used in the construction of the escalator handrail?
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What role do the pressure rollers play in the escalator handrail system?
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Where are the guide rollers positioned in the escalator handrail system?
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What two sides does the drive wheel of the escalator have?
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What purpose does the formed steel guide serve in the escalator system?
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What is the function of the nips formed by the pressure rollers in the escalator system?
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What is the primary function of the handrail drive chain?
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Where are the handrail take-up devices located?
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What is the purpose of the adjustable take-up sprocket in the handrail drive chain system?
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What does the handrail take-up device utilize to adjust slack in the handrail?
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How do handrail support rollers contribute to the escalator's operation?
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What mechanism ensures that the handrail is driven properly?
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Why is the long handrail take-up device significantly important?
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What type of lubrication system is used for the handrail drive chain?
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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.