1. Final Project - Vertical Transportation Flashcards
Hydraulic elevator
• Used for low-rise, or less than 5 story buildings, or about 50’-0”
• Speed varies between 25 - 150 feet per minute
• Can carry about 10 tons
• Commonly used for freight in industrial and low-rise commercial buildings,
passengers in small buildings, or single family residential
• Sit over a plunger or ram which operates a cylinder that extends as far into the
ground as it is tall.
• Holeless Hydraulic: uses a telescoping plunger set into the shaft next to the
cab. Lift is provided by applying force to the upper member of the car frame
• Oil serves as the pressure fluid and is controlled by high speed pumps
- Main advantage: don’t require a penthouse machine room or heavily braced roof over the shaft
- Cost less than electric elevators because they are more simple
Electric (Traction) Elevator:
- Used in commercial and industrial buildings greater than 5 stories/50’-0”
- Speeds up to 1,800 feet per minute
- Capacities up to 10,000 pounds
• Traction is used to transmit lifting power to the hoisting cables by means of
friction that develops when cables run over grooves in the sheave
• On one end is the elevator cab and the other are counterweights that weigh
about the weight of an empty car plus 40% of the live load capacity
• Traction machine: Motor and drum assembly that is geared or gearless
• Gearless: motor, sheave, and break all mounded on a common shaft, so 1
revolution of the motor means one turn of the main sheave (typically used for passenger service)
• Geared: motor and break on one shaft which drives a second main shaft, used for high speed installation
• Roping: the arrangement of cables supporting the elevator
• Single wrap: simplest, cables pass only once over elevator machine sheave and
then connected to the counterweight
Freight Elevators:
• Designed only to transport equipment and materials (and the passengers needed to handle them)
• Commonly available in 2500 lbs - 8000 lbs
• Freight elevators are available as standard designs for capacities of up to
20,000 lbs beyond this point, they must be specially engineered.
• Speeds range from 50 ftm - 200 ftm
• Capacity takes prescience over speed
Safety features:
- Numerous due to all the potential hazards
- Main Break: is mounded on shaft and operated by the control mechanism
- Break is self applying so the car will stop in the event of a power failure
- Governor: measures and limits the elevator speed by means of the control panel.
- It will actuate the safety rail clamp if the elevator tries to exceed its proper rate of travel
• Safety Rail Clamps: grip the side of the rails if there is an emergency
• Car Buffers/Bumpers: located on the bottom to stop the car if it over travels at
low speed….won’t do much to stop a car traveling at a higher speed
- Interlocks: prevent the elevator from operating unless the hoistway door is closed and locked
- Safety Edges: Doors have spring loaded lip that retract open if it encounters a person/object when attempting to close
• Proximity Dictators: similar to safety edges, but senses the presence of a
person near the door and can stop the closing motion
• Cabs will self level to reduce tripping hazard
single automatic
elevator can only be called if no one is using it, and once inside, the passenger has exclusive use of elevator until trip is complete
-only good for small buildings with light traffic
selective collective operation;
most common operating system for elevators
- elevator remembers and answers all calls in one direction and then reverses and answers all calls in the opposite direction
- when trip is comlete the elevator can return to home landing
- light to moderate traffic
group automatic operation:
- used for large buidlings
- control of all elevators with programmable mocroprocessors to respond to calls in the most efficient manner possible, taking into account all variables
- time of day and day of week can be programmed
elevator lobbies shouldn’t have more than ___ elevators
8
elevator lobbies shouldn’t have more than ___ elevators on one side
4
the standard speed and angle for escalators is
100 feet per minute (1-2ft per second)
30 degrees from horiizontal
Which of the following types of elevators is used for high rise office buildings
a. standard hydraulic
b. high speed hydraulic
c. geared traction
d. gearless traction
d. gearless traction
- one type of mechanism used for high speed elevators, which a high rise building would require
geared traction elevators are used for
low speed and high capacity
hydraulic elevators are used in
buildings from two to five stories, or up to about 50 ft
for a three story department store, the most important variable for selecting an elevator would be
a. speed
b. capacity
c. control method
d. machine room location
b. capacity
a department store requires elevators with high capacity. That is the amount of wight the elevatos can carry, which translates into the aloowable number of people on the elevator at any one time, is a priority
an underground transit station is best served with
a. escalators and elevators
b. stairs and escalators
c. stairs and elevators
d. moving walks and elevators
a. escalators and elevators
a transit system must move large numbers of people quickly as well as provide accessibility. a combo of escalators and elevators
-stairs may provieded as a secondary method of vertical transport but would require more room to move the same number of people
