Presentation on theme: "Escalators: 30 degree incline is standard. Escalators An escalator is a conveyor transport device for transporting people, consisting of individual, linked."— Presentation transcript:
Escalators: 30 degree incline is standard
Escalators An escalator is a conveyor transport device for transporting people, consisting of individual, linked steps that move up or down on tracks, which keep the treads horizontal. As a power-driven, continuous moving stairway designed to transport passengers up and down short vertical distances, escalators are used around the world to move pedestrian traffic in places where elevators would be impractical. Principal areas of usage include department stores, shopping malls, airports, transit systems, convention centers, hotels, and public buildings.
Escalators The benefits of escalators are many. They have the capacity to move large numbers of people, and they can be placed in the same physical space as one might install a staircase. They have no waiting interval (except during very heavy traffic), they can be used to guide people toward main exits or special exhibits, and they may be weather-proofed for outdoor use. As recently as 2004, it was estimated that the United States had more than 30,000 escalators, and that 90 billion riders traveled on escalators each year.
Escalators are one of the largest, most expensive machines people use on a regular basis, but also one of the simplest. Escalators are one of the largest, most expensive machines people use on a regular basis, but they're also one of the simplest. At its most basic level, an escalator is just a simple variation on the conveyer belt. A pair of rotating chain loops pull a series of stairs in a constant cycle, moving a lot of people a short distance at a good speed.
how escalators work
Each step in the escalator has two sets of wheels, which roll along two separate tracks. The upper set (the wheels near the top of the step) are connected to the rotating chains, and so are pulled by the drive gear at the top of the escalator. The other set of wheels simply glides along its track, following behind the first set.
The tracks are spaced apart in such a way that each step will always remain level. At the top and bottom of the escalator, the tracks level off to a horizontal position, flattening the stairway. Each step has a series of grooves in it, so it will fit together with the steps behind it and in front of it during this flattening.
handrails In addition to rotating the main chain loops, the electric motor in an escalator also moves the handrails. A handrail is simply a rubber conveyer belt that is looped around a series of wheels. This belt is precisely configured so that it moves at exactly the same speed as the steps, to give riders some stability.
escalator speed Escalator speeds vary from about 90 feet per minute to 180 feet per minute (27 to 55 meters per minute). An escalator moving 145 feet (44 m) per minute can carry more than 10,000 people an hour -- many more people than a standard elevator.
Did your old house come "in the mail"? Between 1906 and 1940, thousands of North American homes were built according to plans sold by mail order companies such as Sears and Montgomery Wards. Often the entire mail order house (in the form of labeled timbers) came via freight train. Other times, builders used local materials to construct homes according to the mail order catalog house plans. Catalog house plans by Sears, Montgomery Wards, Aladdin, and other companies were widely distributed in the United States and Canada.
How do you find Sears houses? It's not easy. Start your search with a reference work, such as "Houses by Mail: A Guide to Houses from Sears, Roebuck and Company," or Dover Publishing's reprint of the 1926 Sears Modern Homes catalogue. Study front porches and roof lines. Original front porches can have several easy- to-spot clues. Look at the stick-work on the front porch columns and the interesting millwork on the 3-part front porch columns. Note the small block of wood, centered on the front porch roof's trim. The roof line of the Sunbeam and Windsor extends much further on the front of the house than the back.
‘The Sunbeam’ catalog house. Note the interesting millwork on the porch of this Sunbeam house in the catalog picture
Sears Catalogue Homes - Between 1908 and 1940, Sears customers ordered over 75,000 houses from Sears Roebuck and Company mail-order catalogs. Prices for these build-it-yourself kit houses ranged from $600 to $6000.
The customer selected a house design from the Sears Modern Homes catalog. They received a bill of materials list and full blueprints. A few weeks after the order was placed, two boxcars containing approximately 30,000 pieces of house would arrive at the nearest train depot.
A 75-page instruction book told homeowners how to assemble those pieces. The best way to identify a Sears home is to obtain a copy of the original Houses By Mail catalogue.