A very old wish for a good night’s rest is “Sleep tight, and don’t let the bedbugs bite.” This is testimony to the fact that bed bug bites can disturb sleep, robbing a person of needed rest. Bed bugs have been recorded in ancient history, being mentioned as early as 400 BC. The historical accounts of these insects indicates their spread from the Mediterranean region to northern Europe, then to North America. Our word “bug” is derived from bugge, the original English name for these creatures.
The bed bug (Cimex lectularius) is a small, oval, flat wingless insect. Its only food is blood. The bedbug has mouth parts designed to pierce the skin of a host, inject an anti-coagulant with a painkiller, and suck the blood. A bed-bug can survive as long as half-a-year on one meal. These small parasites–an adult is only 5mm long–can hide in almost any crack or crevasse.
Bed bugs are so called because they are usually found in and around beds and mattresses. They can slip through the seams of mattress covers, hide in a box spring, or seclude themselves in the frames and upholstery of other furniture, or behind baseboards. Their small size and avoidance of light makes them hard to see, but signs of their presence can be found: feces, molted skins, stains from crushed bugs, etc., even odor.
The most personal sign of bed bugs is their bite. When a bedbug bites, a pain killer is injected along with the anti-coagulant. This anesthetic keeps the victim numbed long enough for the bug to finish its meal. But later, the bite site begins to itch. It may swell and become fevered. If scratched or rubbed, it can become infected. It is the irritation of the bite which disturbs sleepers, causing restlessness.
From the time they hatch until they die, bedbugs are bloodsuckers. The chart above shows their average sizes from the egg to adult from less than 1 mm as a newly hatched nymph to the 5 mm long adult.
Bed bugs had become almost unheard of in North America and Western Europe, but now they have made a comeback. A few years ago, these pests were being found in many high-class hotels. This has been blamed on travelers going to and from areas of the world where bed bugs and other parasites are common. Due to their minute size and secretive habits, they hitchike unnoticed in luggage.
Because they hide so well, bed bugs are hard to combat. Complicating this is the fact that many of them have become resistant to insecticides. The only sure way to eliminate bedbugs in a room is to heat it to about 130° F long enough to kill them. This is a job better left to experts who know how to do it safely.
The most effective way to prevent bed bug bites is to keep the little critters from getting to you. As noted in a previous Beds Blog article, mattress encasement serves this purpose two ways. First, bedbugs cannot get into a properly encased mattress. Secondly, if a bed bug happens to already be in a mattress, encasement will keep it from biting you.
All the seams in an effective mattress encasement will be sealed to close this avenue. And the zipper must have not gaps in the teeth big enough for a bed-bug, with the zipper kept tightly closed at the end. Some manufacturers of encasements have a special bug-proof zipper for this purpose.
The most effective means of prevention is to deny the bed-bugs a place to hide or to prevent them from getting up to the bed. This means reducung or eliminating clutter. Other measures are keeping bedding from touching the floor and drying bedding and nightclothes with heat to kill any bugs which may be there, and thoroughly cleaning luggage when returning from a trip. A couple of generations ago, some people placed the feet of their beds in cans or pans of kerosene and kept the bed away from the wall. This worked because bed bugs cannot fly or jump.
Bed bugs have not been found to transmit disease-causing organisms from one human to another, even though they ingest pathogens with a host’s blood. The apparent reason for this is that, unlike mosquitoes, bed-bugs do not insert any of a previous host’s blood when they inject the anti-coalgulant. However, there is the opportunity for infection to enter the wound. Also, some persons may be allergic to bedbugs with the potential for a serious reaction, especially if they are already allergic to other insect bites and stings.
Although the potential for infectious diseases from bed bugs may be very low, sleep disturbance and lack of rest can be a hinderance to good health. We all need a good night’s rest, and one way is to not let the bed bugs bite.
Sleep Train: http://www.sleeptrain.com/education-bed-bugs.html
Many producers and sellers label or describe their merchandise as “natural” or “organic” products. “Organic” and “natural” food, clothing, bedding and many other goods are fashionable. Significant numbers of shoppers now ask, “Is it natural? Is it organic?”
Two concerns drive this trend: health and the environment. There is also, for some, a philosophical or religious undertone, a belief that there is an intrinsic value to being as natural or organic as possible. While the last perspective may be considered debatable by many, the first two considerations do have some empirical basis.
Before going on, let’s define natural and organic.
Natural materials are those produced by natural means, as opposed to artificial materials. These may be produced by plants or animals or be naturally ocurring compounds and elements (for example, minerals). For instance, natural fibers include linen (plant), wool (animal) and asbestos (mineral). One fiber used in bedding and clothing is on the borderline between natural and artificial. Rayon is naturally produced cellulose, but it has been extracted and liquified from natural sources and reconstituted as sheets (cellophane) and fiber (rayon/viscose).
Organic is not the same as natural, though it is related. Cotton, for instance, is a natural fiber, but not necessarily organic. Modern cotton farming uses chemical fertilizers and pesticides. Organic farming, whether of cotton or some other crop, is without any applications of chemicals. Being organic extends to the processing of raw materials into finished products without the uses of harmful substances.
There is good reason to be concerned about the impact of what we eat, wear, sleep on or otherwise use on our health. Many things once assumed to be safe have now been found to be detrimental to health, some even deadly. For example, Paris green was a fashionable color for walls. then people with Paris green in their houses became ill, some even dying. The pigments in Paris green contained arsenic, which escaped into the air and poisoned the residents. Now we ban lead-based paint and asbestos because they are health hazards.
Many chemicals used in agriculture and manufacturing are suspected or proven health hazards. Notable are pesticides and fungicides, designed to be deadly to organisms that damage and destroy crops, and chemical fire retardants applied to clothing and bedding. Also suspect are cleaning and bleaching agents and certain fabric dyes and food colorings. Recently added to the list are BPAs used in plastics.
Concern for the environment includes not just the natural ecosystem, but also those who work in the fields, mines and factories, and the communities in which they live and work. Today, for many, this also includes the economies where materials are produced and products made.
The keyword for agriculture is now not just organic, but organic and sustainable. More than how a crop is fertilized and pests are controlled, it is also how agricultural practices treat the land itself. Consumers today want to know how rubber plantations affect the rainforests, how much water is used on the cotton, and whether trees cut for wood used in the foundations are replanted.
This is the easy question. The two sources of natural materials in beds and bedding are plants and animals. These include fibers in the textiles and padding, wood for frames and slats, and oils for foams. It also includes plant-based dyes for fabrics.
Until early in the 20th Century, all fibers used in textiles came from either plants or animals. Even the first man-made fiber was made of cellulose extracted from plants. Plant produced fibers used in beds include cotton, linen (flax), kapok, bamboo fibers, hemp, sisal, ramie, and others. Some of these, such as cotton, come from the seed pods. Linen is from the bast (outer layer) of flax stems. Hemp fiber is from the hemp stem, while coconut fiber comes from the seed itself.
Organic concerns for plant fibers are the fertilizers and pesticides used in growing the plants. For instance, raising cotton uses an extraodinarily large proportion of pesticides and fertilizer compared to other crops. Only in the past two decades has raising cotton organically become economically viable.
With bast fibers, this extends to extraction of the fibers. Traditionally, linen fibers have been extracted from flax stems by retting, letting the stems rot until the fibers are separated. Modern extraction uses acids or enzymes to speed the process. However, disposal of the retting water is a problem.
Bleaching of plant fibers raises environmental concerns, especially with the disposal of liquid waste.
Animal fibers are the oldset used in clothing. Wool seems to be the longest used animal fiber. Other animal fibers used are cashmere and mohair (goat hair), alpaca, angora (rabbit) and silk. All but silk are hairs shorn or combed from the animal. Silk is threads extruded by silk moth caterpillars to make thier cocoons.
Concerns related to animal fibers are care of the animal, pest control and processing the fiber. Does raising the animals damage the land? Are the animals treated humanely?
With wool, are chemicals used to treat the sheep for ticks? How is the wool cleaned after shearing?
In 2013, leaders of clothing companies discussed the environmental impact of their businesses, whether synthetic or natural. The answer was not simple. It was complicated by the raising of cotton, the most widely used natural plant fiber. The same issue is also faced in choices of materials for mattresses, pillows, sheets and blankets.
Organic Trade Association – http://www.ota.com/
Organic.org – http://www.organic.org/articles/showarticle/article-224
NCBI – NIH – http://www.ncbi.nlm.nih.gov/pubmed/10968564
Sustainable Cotton Project – http://www.sustainablecotton.org/
CoolNotCruel – http://www.coolnotcruel.com/
Hemp Industries Association (NA) – www.thehia.org
Natural Life Magazine – http://www.life.ca/naturallife/0406/organic_fibers.htm
Vermont Organic Fiber – http://vtorganicfiber.com/
Fabric University | Fabric Seminar | Fiber History – http://www.fabriclink.com/university/history.cfm
Suppose someone taking a survey asked you, “Do you get enough sleep?” How would you answer? The answer to this depends on knowing the answers to two other questions: “How much sleep do you get?” and “How much sleep do you need?”
For most of us that means how long do we sleep in bed at night? That is, minus interruptions. New parents know all about this, waking up to check on the wee one, responding to a cry or a whimper in the dark, taking time to feed, change, or rock the newest member of the family. But most of us sleep through hours at a time with little or no interruption.
For some others, this includes a nap or two taken during the day. This may include a new mother or father compensating for nighttime interruptions. It could include a rotating shift worker trying to reset his body clock on days off. Sometimes it is a bored stay-at-home person, or an older adult whose body no longer tolerates lying down very long at one time.
The simplest answer is, “That all depends.” How much sleep is needed depends on a few factors, such as developmental stage, age, sex, physical condition, and health. It may also be affected by the demands of ones occupation. It may surprise many to learn that more rest may be necessary for non-physical work requiring alertness and a sharp mind than for physically demanding jobs.
It is common knowledge that babies sleep a lot. A newborn is asleep for more time than awake. By the time an infant is a year old, this balance is even or reversed, but a large part of the day is still spent sleeping. Kindergarten used to be known for the naptimes when the entire class lay on their mats. By the time a child is in the grades, all the school day is waking hours. The average time needed for sleep lessens as one approaches adulthood, where it levels off for the last two-thirds of a person’s expected lifetime. But in the senior years, it does shrink by about an hour.
I was surprised to learn how prevalent sleep deprivation is. Study after study shows that a significant percentage of people own up to dozing in meetings, glazing over while working, and driving while drowsy, some of the common signs of not enough sleep. This and statistics underscore the importance of adequate sleep. Lack of sleep causes accidents on the road, in the shop and at home. Quality of products depends on engineers, technicians, operators and inspectors being alert. How many costly recalls are due to sleep deprivation? How much lost business? How many injuries and loss of life? Sleep deprivation has economic and social costs.
Most youth enter adolescence during their teenage years. The hormonal changes include the circadian rhythm, the cycle of wakefulness and sleep. The adolescents naturally stay awake later (such as until 11 PM) and naturally wake up later. Studies show that they need, on the average, 8½ to 9½ hours of sleep a night. This includes a long deep-sleep (slow-wave) cycle in addition to the REM (Rapid Eye Movement) cycle.
Statistics show that sleep deprived high school students have more traffic accidents, doze more in class, and have lower scores on tests. One contributing factor in teen sleep deprivation is early school hours. High school students do better overall when school begins at 8:30 AM or later (the “ten-o-clock scholar” in the nursery rhyme).
Class schedules are not the only culprit in teens’ lack of sleep. Others include extracurricular school activities, non-school activities, and modern technology. Some of the observations made by organizations and professionals include keeping electronic devices out of the bedroom and allowing non-structured social time within accepted waking hours. Also recommended is encouraging and promoting physical activity each day. Of course, it is easier to motivate a teen to get more sleep when we set the example.
Several organizations have recommended hours of sleep for childrenn, youth and adults. The National Sleep Foundation, which Beds.org is a member of, has used decades of sleep research to make a chart of recommended hours of sleep per night for nine age groups: Newborn (0-3 month), Infant (4-11 months), Toddler (1-2 years), Pre-school (3-5 years), School age (6-13 years), Teenage (14-17 years), Young adult (18-25 years), Adult (26-64 years), and Older adult (65 years and older). In each of these categories, the recommendation is a range of hours per day, from 14-17 hours for a newborn to 7-8 hours for an older adult. Outside each recommended range is a range of acceptable hours, from 11-19 to 5-9.
The ranges of hours of sleep are based on the needs of members of each age group. However, we are individuals, and our need of sleep does differ from one person to another. The same studies leading to these recommendations also show that some individuals require more or less sleep than the hours in the range for their age group. When considering our own needs, it can be hard to be objective, so it is wise to listen to other’s observations, such as, “You’ve been more irritable lately,” and “You’re nodding off.”
How much sleep we need involves not only the number of hours, but the quality of sleep itself. Our health status affects how long and how well we sleep. So do our activities and what and when we eat.
Another factor in how well and how long we sleep is what we wear. Even in a climate-controlled house, this can be a seasonal issue. We want to be warm enough in the winter and not too warm in the summer. Also, of course, irritating and ill-fitting nightclothes would interfere with sleep.
Another major factor is the bed. In this case, each one of us is a Goldilocks. Is the mattress too hard, too soft or just right? Mattresses are available from ultra firm to ultra plush and the range between. Do we prefer to lie on or in the bed? This could be the difference between memory foam and latex. Does a partner’s snoring or motion keep you awake? Motion isolation will eliminate partner movement disturbance. Is the bed too small? The next size up helps. Can you find the optimal position? Here’s where adjustable beds come in, and some of them deal with the snoring issue too. With so many choices, it pays to know what you yourself need and look for a mattress and bed that meet those needs.
National Sleep Foundation <http://sleepfoundation.org/how-sleep-works/how-much-sleep-do-we-really-need>
Center for Disease Control <http://www.cdc.gov/features/dssleep/>
Huffington Post <http://www.huffingtonpost.com/2013/12/20/get-enough-sleep_n_4475645.html>
Almost eleven months ago I posted an article about wood coils, a new kind of mattress innerspring invented and developed by a Hungarian company. Not long before the launch of wooden coils in the bedding market, another new kind of mattress spring was invented and introduced into the market by Willy Poppe, a Belgian. Poppe is CEO of a family-owned bedding manufacturer, Diamond Spring Company, in Sint-Niklaas, East Flanders, Belgium.
Willy Poppe’s invention is the foam spring, an eight-sided hollow column made of memory foam. The column is cut in a honeycomb pattern, which resembles expanded metal. Poppe dubbed this “Octaspring.” the Octaspring can be compressed like a spring. According to Willy Poppe in a video, these MemoryCoils were first used in memory foam pillows. However, while these memory foam springs worked well in pillows, they were not firm enough for mattresses. So the Octasprings were reinforced with the addition of firmer polyurethane. These EcoSprings could be made soft or firm or somewhere in between.
Now a grid of Octasprings would be the support core of a mattress. With a 1″ foam layer between, one layer of foam springs can be placed on another. Dormeo, a company set up to manufacture and distribute Octaspring memory foam matresses, has models with one to three foam core layers.
One advantage of foam springs instead of metal is that they are not felt the way metal springs are. Also, like the wood coils reviewed earlier, they do not focus environmental electromagnetic radiation on the users.
An additional advantage is airflow. The honeycomb cuts go all the way to the open core of the Octaspring, allowing air to flow all the way through. Pressing down on the “coil” forces air out, and releasing pressure lets it back in. So any movement by the sleeper pumps air through the mattress, increasing the cooling effect, another advantage over metal springs.
The article on wooden coils ended with a paragraph asking, “What Will They Make Springs from Next?” Foam springs were already being made, and foam spring mattresses are selling. Look for other firms to develop their own types of foam springs or buy a license to make Octasprings, the way that Tempur-Pedic was quickly and widely imitated in using memory foam.
Nylon is a thermoplastic amide polymer.* Invented in 1935 by DuPont chemical engineer Wallace Carothers and first used for toothbrush bristles, nylon is the most used synthetic fiber. In 1940 it was introduced as a substitute for silk in stockings. Nylon is very similar to silk, and with Japanese occupation of China the supply of silk was restricted. Then in 1942, nylon replaced silk in parachutes. Ripstop nylon, developed for sturdier parachutes, is now used for tents and awnings, coats, ponchos, and bags. And solid nylon is used for gears, rollers and bearings in light applications. By the way, it is still widely used for toothbrush bristles.
Nylon is also used in mattresses. Invacare and Paramount Mattress use nylon in covers of institutional and healthcare mattresses. Some Beautyrest Recharge mattresses use a nylon/polyester blend. Boyd Specialty Sleep uses nylon tricot in the covers of the support modules for its Broyhill Cube Series mattresses.
The two variations of nylon used today are nylon 6,6 and nylon 6. With essentially the same final product, the difference between these two is how they are made. The 6 stands for the six carbon atoms in the precursor molecule. Nylon 6,6 was patented by DuPont, so other manufacturers had to find another way to make nylon. DuPont‘s process simply linked two six-carbon chain molecules together with amide bonds (which also exist in silk). Other manufacturers discovered how to open the ring of an aromatic molecule (one with a six-carbon ring) and link it to others. Either way, what you get is nylon.
Two other types of fiber developed from nylon are Kevlar® and Nomex®. Nomex replaced asbestos in fireproof clothing, and Kevlar is used for bulletproof vests. These are called aramids, because they are actually made of carbon rings.
Nylon is not widely used in mattress covers. Except for the Beautyrest Recharge, it is used in top panels of healthcare and institutional beds. The advantage of nylon in this usage is that it can be resist fluids and still be breathable. This protects the mattress foam core and is easy to clean without trapping heat the way totally impermeable vinyl would. Boyd uses it for its support cubes so they can be removed and reinserted easily.
Thermoplastic means that it gets softer when heated.
Polymer means that it is made of bonded chains of similar molecules.
Amide means that one molecule is bonded to the next by an amide group: one atom of nitrogen with a hydrogen atom (NH) linked to a carbon atom with a double bond to an oxygen atom (C=O). The link can be typed out as NH-C=O. The two components are linked to the N and the C respectively.
Several manufacturers claim that some or all of the foams used in their mattresses are either partially or wholly made from plant oils. Terms used for these are soy foam, plant-based, botanical-oil, natural oils, etc. Plant oils used include those extracted from soy beans, castor beans, canola (rapeseed), palm kernel, coconut, peanuts, and other seeds. How are these oils used in making foam? And how does this affect the use of fossil fuel sources (petroleum and coal oil)?
Oil itself does not form foam, at least not the kind you can sleep on. Bedding and furniture foams, other than latex foam (foam rubber), are forms of polyurethane foam, a semi-rigid, flexible material which is both supportive and cushioning. Polyurethane is a polymer, chains of repeated links of molecules. These molecules are polyols, alcohols with several hydroxyl branches. An alcohol is an oil (hydrocarbon) which is partly oxidized. A hydroxyl is an -OH branch of oxygen and hydrogen.
Some polyols are always produced when refining petroleum. One plant oil, castor bean oil, contains a natural polyol. Most other plant oils have to be modifed to make polyols. The components of these oils are fatty acids, like mono-, di- and triglycerides, the precursors of cholesterol. The fatty acids used are long chains with a double carbon bond (C=C on a diagram) in the middle. Using ozone or other reactors, hydroxyls are added to the chains.
To make the polyurethane, the polyols are combined with isocyanates. The reactions form endless chains which cross-link to form the polyurethane. Gasses released by the reactions and air introduced during the process make the foam.
Until recently, only a small portion of petroleum in polyurethane foam could be replace by plant polyols (aka biopolyols) and still produce a quality foam. Refinement of the process, including using water for the solvent, make it possible to use a higher percentage of biopolyols. However, we need to carefully examine the claims of manufacturers and retailers in promoting their products. Don’t be afraid to ask what proportion of the oils used in making the foams are plant derived.
Use of polyols derived from natural plant oils reduces the use of petroleum in more than one way. First, it means less petroleum is used as the raw material. Second, this means less petroleum used as fuel for refining petroleum for polyols. Third, modifying plant oils requires less energy.
Other advantages of using plant polyols in manufacturing polyurethane and its derivative foams include 1) less or no VOCs (volatile organic compounds), and 2) less degradation of the foam by moisture (such as from sweat), and some plant-oil foams are less flammable.
However, use of plant oils has its own environmental concerns. First is land use for growing plant oil crops. Is the land chosen wisely? Or does it degrade natural resources (such as rain forests)? Second, are the farming practices environmentally acceptable? This includes preventing erosion and whether chemical pesticides, herbicides and fertilizers are used. Also, does raising and using plants for this purpose compete with food crops, thereby raising food prices?
In the final analysis, using natural plant oils to make polyurethane, memory foam, and other foams for bedding products is a net benefit for health, safety, and the environment. And this will grow as technological development improves the processes involved.
Damask is not a fiber, but a style of weaving, named for Damascus, Syria, where silk and linen were woven in this manner in the early Middle Ages. In damask weaving, patterns are created by longer warp threads on top (satin) for the foreground, and longer woof threads (sateen) for the background. This pattern is reversible, meaning the the negative image appears on the back side of the fabric. This was more commonly done with one color (monochrome). Damask can also be done with multiple colors (polychrome). In either case, the image is created by the pattern of weaving.
At the end of the Middle Ages, the art of damask weaving was brought to Italy, then spread across Europe. Many damask fabrics used in the bedding industries are produced in Belgium.
Today, most damask weaving is done with Jacquard looms. Invented in 1801 in France, these were controlled by punched paper cards, then by punch-hole paper tape. Now jacquard looms are controlled by digital computers.
The most common uses of damask are in tablecloths and draperies, sometimes in clothing. Several bedding manufacturers, for example Simmons Beautyrest, Sealy, E. S. Kluft, and Parklane Mattresses, use damask in the covers of some of their mattresses, often with the name and/or logo of the company repeated in the pattern.
Besides weaving, a style of knitting producing the same effect, also called damask, is used on mattresses, especially memory foam, latex, or foam-topped models. Fibers used include cotton, linen, polyester, silk and rayon.
Cashmere is also known as cashmere wool, though it is not really wool (like that shorn from sheep), but a type of goat hair. It is considered a luxury fabric, more expensive than wool. Whether woven or knit, it is a fine fabric which becomes softer with use. Commonly used in shawls, sweaters, scarves and hats, cashmere is also used by some manufacturers in the covers of select mattresses. A few of these manufacturers are Kingsdown, Magniflex, Stearns & Foster, Simmons Beautyrest, Parklane, Spring Air, Serta, Shifman, and E. S. Kluft.
Cashmere is considered a warmer fabric, while silk is considered cool. Therefore it is sometimes paired with silk in flippable toppers with a Winter side and a Summer side.
Cashmere, is named after Kashmir (Cashmere is the British spelling), a former kingdom in an area now divided between India and Pakistan. This is where commercial production of cashmere began in the Middle Ages. Before this, cashmere fabric was made and used locally.
Cashmere is the undercoat of long-haired goats [Capra hircus laniger and related breeds], which are now known as cashmere goats. These goats originated in Kashmir and adjoining areas, then spread through China into Mongolia as herders migrated. Currently, the three largest producers of cashmere hair (also called cashmere wool) are China, Mongolia and Afghanistan.
To be legitimately called cashmere, the fibers must meet certain standards. United States law (U.S. Wool Products Labeling Act of 1939) defines cashmere as 1) the finer, softer undercoat (also called down) of the cashmere goat, 2) with an average fiber diameter 19 microns or less, and 3) less than 3% of fibers larger than 30 microns in diameter.
The common method of gathering the down is combing it out when the goat is shedding. After this, the hair is washed, then the longer coarse guard hairs are removed. It is the combed raw cashmere which is usually sold on the world market. Buyers of raw cashmere spin it into thread and yarn.
Production of cashmere textiles in Europe began when Marco Polo brought cashmere back to Italy in the 1200s. In the 1800s cashmere textile production began in France and Scotland. It spread to America in the 20th Century.
Care instructions for cashmere most commonly say, “Dry Clean Only.” But the best method for cleaning cashmere is hand-washing in cold water, blotting and laying flat to dry without heat.
Pocket coils were invented at the end of the 19th Century (1800’s) by James Marshall, who began manufacturing them about 1900. Since then, individually wrapped pocket coils have been adopted by most of the major manufacturers of innerspring mattresses.
A more recent development in pocket coils is coil-in-coil technology. The concept is simple: a smaller, firmer coil inside a larger, softer coil. Two of the mattress companies using this technology state that the two coils are made from one wire, and photos of the others show this feature, which is also described in the patent application. Most of the coil-in-coil springs are straight cylinders, but the Joey Coils used by Simmons Singapore are barrel-shaped (a little narrower at the ends).
Before this, manufacturers had used other means to make dual-response springs. The oldest method was the hourglass shape, as in Bonnell coils. The narrower middle with more stretched-out turns compresses more easily for a softer response, while the broader ends with more closely spaced turns is firmer for more support. This concept is also exhibited in offset coils. At least one manufacturer tried variable-gauge coils and S-springs, where part of the spring wire is a heavier gauge. Also tried is alternating heavier and lighter coils.
Sometimes called “dual coil technology” (not to be confused with one coil layer atop another), there are a number of trade names for springs using this technology. For instance, Leggett & Platt Components Europe makes Joey Coils. According to A.H. Beard, the Australian mattress company, they are named after the kangaroo and are sometimes called “pouched coils.” The Serta iSeries hybrid mattresses use Duet™ Coils. And in Stearns & Foster‘s Estate Collection these are Intellicoil® Encased Coils.
Coil-in-coil technology is not as widely used as the parent pocket coils are, mostly due to how new they are—less than a decade. But usage is significant considering who uses it: Stearns & Foster, Serta, Paramount Sleep, and Simmons. These are the companies whose lead is followed by others. Coil-in-coil technology may also be used in children’s mattresses (called 2-in-1 coils with a graded response), but I do not yet have confirmation of this.
Coil-in-coil technology is, for now, used in more expensive mattresses. However, their use in Serta‘s middle-priced iSeries models points to a future of more efficient production with lower costs, resulting in a more widespread presence in mattresses. A key advantage for them is the suitability of the coil-in-coil design for couples of significantly different body sizes.
Pocket coils, also known as pocketed coils, encased coils, wrapped coils or Marshall coils, are light gauge open-end coils in fabric pockets. They were invented in 1900 by James Marshall, an Englishman who migrated to Canada. In Toronto, Ontario, Canada he founded the Marshall Mattress Company to make mattresses using his technology. The company is still in business, focusing solely on pocket coil mattresses. It was featured in a 2011 BedTimes Magazine story.
The pockets are attached to each other, but the coils are not. This allows each coil to respond independently to weight place directly on it. According to Brad Warner, owner of Marshall Mattress, the pocket coils were invented to meet a need: “Legend has it that Mrs. M. was bedridden and Marshall created the support system for her, with coils wrapped in unbleached muslin, quilted with horsehair and outer tufted.”
At first, since they had to be made and encased by hand, pocket coils cost so much to manufacture that they could be used in only the most expensive mattresses. Then in 1925, Simmons engineer J. F. Gail invented a machine to make the coils and insert them into cotton pockets. This reduced the cost of a pocket coil mattress enough to place it in the general market.
Pocket coils are now very common around the globe. According to Marshall Mattress, “Marshall’s pocket spring-filled mattress system has become the original worldwide standard for spring-filled mattress construction and remains to this day.”
The main advantage of Marshall coils is the individualized support they offer. The independent response of each coil conforms the entire unit to the shape of the user’s body, resulting in even support for the entire body. This means two things:
(1) Larger parts of the body do not bear a disproportionate load. This reduces or eliminates pressure points.
(2) In-between sections of the body are supported. This keeps the spine in proper posture, relieving or preventing back and neck pain.
Refinement of pocket coils is ongoing. Relatively recent developments are microcoils and dual coils. Microcoils are short, small diameter pocket coils. Though no industry-wide standard definition of microcoil has been set, the term is used for coils as much as 4″ tall.
Dual coils are a coil-in-coil design, first patented in 2010 by Sealy engineer L. K. DeMoss. The two coils are made of one wire. They turn in opposite directions. The outer coil is taller with fewer turns, making it more responsive. The inner coil is short and has more turns, making it more supportive. This configuration makes it more durable than the hourglass figure of Bonnell coils, which also have a dual response.
Another development in pocket coils is tall coils, some as much as 10″ high. The objective of this development is to make the mattress less dependent on less durable comfort materials such as memory foam, latex, and foam in general, as well as reducing the overall height of ultra plush innerspring mattresses.
Though pocket coil technology is over 115 years old, the basic value of individually wrapped pocket coils along with continuing development of this form of innerspring support indicates that Marshall coils are here to stay.
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