A Brief History of Elevator Wire Ropes

The humble hoisting rope occupies a unique place in the history of vertical transportation. A simple hemp rope lies at the center of one of the best-known elevator stories — Elisha Graves Otis’ demonstration of his Improved Safety Device at the 1854 Crystal Palace in New York City.

Currently, a sophisticated carbon nanotube “rope” is the primary innovation driving the conceptual (and possibly literal) development of the proposed “space elevator”. However, the wire rope retains pride-of-place in elevator history as the longest-serving suspension means. It is the subject of numerous 19th-century articles that questioned its safety, and has been featured in countless contemporary books, movies and TV programs that predicate disaster on its failure. Today, we look at the introduction of wire elevator ropes in the 19th century and its development into the 20th century.

The invention of wire rope more-or-less paralleled the invention of the passenger elevator, and, by the 1870s, wire rope had become the rope of choice for elevator use. Since they were new, both the elevator and wire rope faced similar challenges regarding safety concerns. The older hemp hoisting rope had a long history of use, and its strengths and weaknesses were well known. However, a rope made of wire was an entirely different matter. This difference was effectively summarized in the June 22, 1878, issue of American Architect and Building News, which included a brief article on elevator ropes. The article expressed the primary concern in its opening sentence:

“The sudden introduction in our large cities of elevators, most of which are hung by wire ropes, has led people to wonder what will happen when they have had a year’s wear, and why there should not, after a while, be a breaking of ropes, and consequent accidents all over the country.”

The key concern centered on the endurance of wire rope and its reaction to constant and repeated bending as it passed around winding drums and over sheaves. One of the aforementioned article’s key assumptions was that “everybody knows, at least, that reiterated bending weakens wire, whether it be by granulation or by the constant extension of its fibers.” The challenge was, in spite of “knowing” that this action occurred, there was no easy way to judge when a rope was no longer safe for use.

The ICS author also addressed rope replacement, noting that “particular attention must be given to the fastenings.” The chief recommendation was to “carefully reproduce the joint as it was originally made” by the elevator manufacturer. A typical shackle used by Otis Elevator is described below in figure 1.

Figure 1: “Otis Elevator Co. Shackle,” ICS Reference Library (1902).

It consists of a split rod, the two legs A, A of which are bulged out and provided with noses at the ends. A collar B straddles the legs and eventually abuts against the noses. The rope is brought through the collar, bent over a thimble C, and passed back again through the collar, after which the free end is fastened by wrapping with wire. The wrapped end of the sections that address elevator ropes serves as a reminder that different elevator systems required different types of rope:

Chapter 1: Standard Methods and Facilities for Testing Wire Ropes
Chapter 2: Materials Composing Wire Rope and Their Properties
Chapter 3: Standard Types of Wire Rope Construction
Chapter 4: Variety of Uses of Wire Rope
Chapter 5: Mechanical Theory of Wire Rope
Chapter 6: Practical Hints and Suggestions
Chapter 7: Instructions on Ordering Wire Rope
Chapter 8: Typical Applications of Wire Rope in Practice

“When ordering rope for elevators, state whether hoisting, counterweight, or hand or valve or safety rope is wanted, also whether right or left lay is desired. The ropes used for these purposes are different and are not interchangeable.”

The diversity of elevator ropes was reflected in the design of American Steel & Wire’s standard hoisting rope, which was produced in six grades or strengths: Iron, Mild Steel, Crucible Cast Steel, Extra Strong Crucible Cast Steel, Plow Steel and Monitor Plow Steel. The company’s standard iron rope was primarily designed for use on drum machines and was “used for elevator hoisting where the strength is sufficient” (Figure 2). It was also described as “almost universally employed for counterweight ropes, except on traction elevators.” Their Mild Steel Elevator Hoisting Rope was designed “especially for traction elevators in tall buildings where, on account of [the] usual quick starting and stopping, a stronger and lighter rope is required.” Shipper or control ropes (also called tiller or hand ropes) differed from standard ropes in that they were composed of six strands of 42 wires each, which were wrapped around seven hemp cores (Figure 3).

wire rope figure 3 and 4

Figure 5: “Side Plunger Hydraulic Elevator,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913).

wire rope fig 5
Figure 5

In addition to providing detailed information on a wide variety of wire ropes, the catalog included schematic drawings that illustrated their proper application. These included 17 elevator-related drawings that depicted direct-, side- and horizontal-plunger hydraulic elevators; geared and traction electric elevators; and electric and belt-driven worm-geared elevators. The drawings’ emphasis on the application of wire ropes makes them a unique resource. Two versions of direct-plunger elevators were depicted — one with a shipper rope and one with an in-car controller — and the presence of two elevation drawings for each system permits a thorough understanding of these elevators (Figure 4). The same level of detail was provided for side-plunger hydraulic elevators (manufactured by Otis) and horizontal-plunger hydraulic systems (Figures 5 and 6).

Figure 6: “Horizontal Hydraulic Elevator,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913)

Figure 5
Figure 6

The electric elevator drawings are of particular interest, because, in 1913, they represented the newest systems on the market. The electric drum machine featured an interesting array of sheaves for the car and counterweight ropes, while the worm-gear machine employed a winding drum located near the midpoint of the shaft (Figures 7 and 8). The traction elevator drawing effectively illustrated its inherent simplicity and the potential of this new design (Figure 9).

The variety of elevator types illustrated in American Steel & Wire’s catalog represented the diversity of elevator systems prevalent in the early 20th century, as well as the importance of wire rope to their operation. Part Two of this article will follow this story through the 1930s, which encompasses the continued development of the traction elevator and the writing of the first elevator safety codes.

Figure 7: “Electric Drum Machine,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913).

Figure 7

Figure 8: “Worm Gear Electric Elevator,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913).

figure 8

Figure 9: “Traction Elevator,” American Wire Rope: Catalog & Handbook, American Steel & Wire (1913).

Figure 9

Original article can be found here at Elevator World Inc. 

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Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.

 

 

Stopping the Drop – Pioneer, Elisha Graves Otis

Elisha-OTIS-1854-Platform

Elisha Graves Otis (August 3, 1811 – April 8, 1861) was an American industrialist, founder of the Otis Elevator Company and inventor of a safety device that prevents elevators from falling if the hoisting cable fails.

Otis

Early years

Otis was born in Halifax, Vermont, to Stephen Otis and Phoebe Glynn. He moved away from home at the age of 19, eventually settling in Troy, New York, where he lived for five years employed as a wagon driver. In 1834, he married and went on to have two children, Charles and Norton. Later that year, Otis suffered a terrible case of pneumonia which nearly killed him, but he earned enough money to move his wife and three-year-old son to the Vermont Hills on the Green River.

He designed and built his own grist mill, but did not earn enough money from it, so he converted it into a saw mill, hoping for better results, but sadly it still didn’t attract customers. Now having a second son and needing to support his family, he started building wagons and carriages. His wife later died, leaving Otis with two sons, one at that time being age 8 and the other still in diapers.

Success and setback

At 34 years old and hoping for a fresh start, he re-married and moved to Albany, New York. He worked as a doll maker for Otis Tingely. Skilled as a craftsman and tired of working all day to make only twelve toys, he invented and patented a robot turner. It could produce bedsteads four times as fast as could be done manually (about fifty a day). His boss gave him a $500 bonus. Otis then moved into his own business. At his leased building, he started designing a safety brake that could stop trains instantly as well as an automatic bread baking oven.

He was put out of business when the stream he was using for a power supply was diverted by the city of Albany to be used for its fresh water supply. In 1851, having no more use for Albany, he first moved to Bergen City, New Jersey (now part of Jersey City) to work as a mechanic, then to Yonkers, New York, as a manager of an abandoned saw mill which he was supposed to convert into a bedstead factory.

Lasting success

At the age of 40, while he was cleaning up the factory, he wondered how he could get all the old debris up to the upper levels of the factory. He had heard of hoisting platforms, but these often broke, and he was unwilling to take the risks. He and his sons, who were also tinkerers, designed their own “safety elevator” and tested it successfully. He initially thought so little of it he neither patented it nor requested a bonus from his superiors for it, nor did he try to sell it. After having made several sales, and after the bedstead factory declined, Otis took the opportunity to make an elevator company out of it, initially called Union Elevator Works and later Otis Brothers & Co.

No orders came to him over the next several months, but soon after, the 1853 New York World’s Fair offered a great chance at publicity. At the New York Crystal Palace,

Otis amazed a crowd when he ordered the only rope holding the platform on which he was standing cut.

Elisha_OTIS_1854
Otis free-fall safety demonstration in 1854

The rope was severed by an axeman, and the platform fell only a few inches before coming to a halt. The safety locking mechanism had worked, and people gained greater willingness to ride in traction elevators; these elevators quickly became the type in most common usage and helped make present day skyscrapers possible.

Otis Elevator Shackle
“Otis Elevator Co. Shackle,” ICS Reference Library (1902).

After the World’s Fair, Otis received continuous orders, doubling each year. He developed different types of engines, like a three-way steam valve engine, which could transition the elevator between up to down and stop it rapidly.

Last years and death

In his spare time, he designed and experimented with his old designs of bread-baking ovens and train brakes, and patented a steam plow in 1857, a rotary oven in 1858, and, with Charles, the oscillating steam engine in 1860. Otis contracted diphtheria and died on April 8, 1861 at age 49.

Ref: Wikipedia

 

 

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Hercules SLR is part of the Hercules Group of Companies which offers a unique portfolio of businesses nationally with locations from coast to coast. Our companies provide an extensive coverage of products and services that support the success of a wide range of business sectors across Canada including the energy, oil & gas, manufacturing, construction, aerospace, infrastructure, utilities, oil and gas, mining and marine industries.

Hercules Group of Companies is comprised of: Hercules SLRHercules Machining & Millwright ServicesSpartan Industrial MarineStellar Industrial Sales and Wire Rope Atlantic.