SLEEPING BAG HAVING OPEN-CELL POLYURETHANE FOAM INSULATION AND A CENTER OPENING WITH MAGNETIC FASTENERS

Abstract

An improved sleeping bag is provided, which has an open-cell, polyurethane or polyether foam insulation layer sandwiched between an outer shell of fully-synthetic, tightly-woven, water-resistant, yet breathable fabric and a more loosely-woven smooth liner fabric, also made of a smooth, fully-synthetic polymeric material. The sleeping bag also has a longitudinal overlapping opening that extends the full length of the bag. Once the two sides of the opening are overlapped, the overlapping sides become secured together with a plurality of magnetic fasteners. Each fastener consists of a magnetic button component, which fits into a magnetic socket component of opposite polarity.

Description

FIELD OF THE INVENTION

The present invention relates to sleeping bags and, more particularly, to sleeping bags insulated with open-cell foam, and having a center opening with magnetic fasteners.

BACKGROUND OF THE INVENTION

The story behind the two tall, distinctive, sturdy red brick buildings, known as the Royal Welsh Warehouse, is one that has touched the lives of us all. It is a story of an entrepreneur who transformed his life, his town and built the future. It is the story of Pryce Jones. Born on Oct. 16, 1834 in Llanllwchaiarn, a village on the outskirts of Newtown in Montgomeryshire of Powys, Wales, Jones was apprenticed to draper, John Davies, of Newtown, at the age of 12. He soon discovered that it was a profession that suited him. In 1859, when he was 25, he opened his own small shop just off Broad Street and traded under his own name. It was from here that he changed forever the shopping experience of the world. He developed a mail order business, beginning in a small way by sending out patterns and stock lists. He knew his market intimately. He knew that there was an untapped market out there in isolated rural locations like mid Wales, where shops were sometimes occasional. Pryce Jones went on to link distribution to production by arranging for local woolen manufacturers and merchants to supply goods to meet the orders he received. Simple but revolutionary. He was always eager to extend the business and he had a gift for publicity. But one product more than any other came to define his business—the Euklisia rug.

The Euklisia rug—a combination of rug, shawl and inflatable pillow—was exported around the world. The very first prototype of the sleeping bag, it was very popular in the German army during the Franco-Prussian war of 1870. It consisted of a woolen blanket with a pocket at the top for an inflatable, vulcanised rubber pillow. The user folded the blanket over and fastened it together. It was exported all over the world to places like the Congo and the Australian outback. Sadly, no known examples survive. Pryce Jones received a British patent for his Euklisia rug in 1876.

Pryce Jones later secured a contract to provide 60,000 rugs to the Russian army, to be supplied at the rate of 6,000 rugs a week during the Russo-Turkisk War. The rugs were used extensively during the siege of Plevna in 1877. However, when the city fell and the Ottoman surrendered, the Russians cancelled the rest of their order, leaving Jones with 17,000 undelivered rugs. He quickly added the Euklisia rug to his catalogue and sold it as inexpensive bedding for charities working with the poor.

Pryce Jones was exceptionally commercially astute. He is believed to be the first person in Wales to install a telephone to link his home, at Dolerw, to his business premises in Newtown. In 1882, while he was campaigning to become Conservative MP for the Montgomery Boroughs, he met the Postmaster General and suggested to him the idea of developing a parcel service. A letter post already existed but parcels had to be sent by road and rail carriers, sometimes at great expense. This was a huge issue for a mail order operation. His idea was adopted and the Parcel Post was developed as a result. The Royal Welsh Warehouse acquired its own printing press and in 1890 produced its first illustrated catalogue to replace the simple price lists that had been sent out previously. In 1901 Jones added his own post office to the Royal Welsh Warehouse, to manage the huge number of packages sent all over the world from Newtown. When Jones was knighted in 1887 for his services to commerce, he expanded his name—much as he had expanded his business—to become Sir Pryce Pryce-Jones.

A modern sleeping bag is an insulated covering for one or more persons. Essentially, it is a lightweight quilt that can be closed with a zipper or similar means to form a tube, which functions as lightweight, portable bedding in situations where a person is sleeping outdoors (e.g. when camping, hiking, hill walking or climbing). It is also commonly used indoors for people who do not have beds or at sleepovers for when one or more persons cannot all fit in the bed or do not feel comfortable sleeping with someone. Its primary purpose is to provide warmth and thermal insulation through its synthetic or down insulation. It also typically has a water-resistant or water-repellent cover that protects, to some extent, against wind chill and light precipitation. However, a tent is typically used in addition to a sleeping bag, as it performs those functions better. The bottom surface also provides some cushioning, but a sleeping pad or camp cot is usually used in addition for that purpose. The bottom surface of a sleeping bag may be moderately water repellent, but a plastic tarp or groundsheet is often used to protect against moist ground.

A number of sleeping bag models are designed for different purposes. Very lightly insulated sleeping bags are designed for summer camping use or for indoor use by children during slumber parties. Well-insulated bags are designed for cold weather use. The most well-insulated and lightweight sleeping bags, which are designed for serious hikers and adventurers, are more expensive than lightly insulated sleeping bags. One subcategory of cold-weather sleeping bag, the mummy bag, is so named because it has an insulated hood for the head. A bivouac sack is a waterproof cover for a sleeping bag that may be used in place of a tent by minimalist, experienced hikers. A bivouac sack may also be carried by day hikers as a backup or emergency shelter, to be used if they cannot make it back to their starting point by nightfall due to inclement weather or getting lost.

For nearly half a century, cold-weather clothing designed by James G. Phillips, Sr. the standard against which all other cold-weather wear is judged. There are two versions of Phillips' cold weather clothing. The first type is designed and engineered fulfill the extreme conditions of arctic living that is defined within the specifications of Phillips Arctic Living System, or PALS™. Such clothing utilizes open cell foam of 2.54 cm (1.0 inch) thickness, and is intended for the most hazardous cold weather conditions. Phillips second type of cold weather clothing, which is referred to as Thermal Johns or TJs™, utilizes open-cell foam of 1.27 cm (0.5 inch) thickness, and is intended to provide superior cold weather comfort and protection down to 12.22 degrees Celsius (10 degrees Fahrenheit), assuming that the wearer has shelter that provides protection from the elements. Though TJS™ is excellent clothing for its intended use, it is not intended to provide the same level of performance as PALS™ clothing.

Phillips discovered that the best moisture handling and insulating performance is realized if foam-insulated clothing is used inside an all-synthetic, tightly-woven, wind-resistant, non-waterproof fabric shell. Moisture inside the clothing—whether produced by the body (perspiration) or entering from the outside (blowing snow, sleet, falling into water)—is moved out of the clothing by the process of moisture vapor transfer. PALS clothing need not be removed in order to dry it out. Body heat will accomplish the task, with most body heat being retained in the process. This technology has been introduced to all branches of the U.S. Military and cold weather explorers who live and work in extreme cold. Phillips introduced this technology and training to the Iditarod mushers in Alaska, where it has been repeatedly used by the winners. Phillips clothing has been worn at the North Pole, South Pole, and many places in between. It was selected and worn by Apollo 13 Astronaut, James A. Lovell, on his North Pole expedition.

In addition to designing insulated clothing, James G. Phillips, Sr., et al. also designed sleeping bags which incorporated open-cell foam as insulation. For example, U.S. Pat. No. 4,843,647 suggests that an emergency bivouac sleep bag can be made using a parka and wind shirt, both of which are open-cell foam-insulated clothing having an all-synthetic, tightly-woven, wind-resistant, non-waterproof fabric shell and a more-loosely-woven all-synthetic liner.

Though the Phillips cold weather garment system is generally held in high regard, it is not without its drawbacks, which include: poor wind resistance and water repellency; difficulties in mass production because of the problems associated with cutting, handling, and sewing one inch thick open cell foam into a finished garment; bulky construction that is uncomfortable to some users; and an appearance that appears “bloated” or Michelin®-man-like. Burlington Industries, Inc. (hereinafter “Burlington”) has been at the forefront of efforts to improve the design of Phillips cold weather clothing. Phillips, Sr. And Gordon K. Scott also designed a cold weather sleeping bag having a snorkel hood and draft curtain, as disclosed in U.S. Pat. No. 4,787,105.

The first patent assigned to “Burlington” is U.S. Pat. No. 4,690,847 to B. Dean Lassiter and Vincent F. Ambrosiani, which discloses a cold weather garment system that includes an upper body garment and a lower body garment. Each garment has three layers: an outer wind resistant shell fabric; an inner loosely knit or woven lining fabric, and a non-flat foam layer between the fabric layers. The face of the foam layer abutting the inner lining fabric is convoluted, having peaks and valleys. The peaks are disposed in a grid-like arrangement, with ridges between the peaks, and four peaks surrounding a valley, and four valleys surrounding a peak. The foam is open cell polyurethane or polyether foam, and has a thickness of at least 0.5 inch, and preferably about one inch. The thickness of the valley portions of the foam is about half that of the peak portions. The convoluted form of the foam increases flexibility, reduces material and weight, and provides added surface area for moisture transfer.

The second patent assigned to Burlington is U.S. Pat. No. 4,734,306 to B. Dean Lassiter, which discloses a cold weather garment that is produced from inner and outer fabrics and a layer of open cell skinned foam that is at least 0.25 inch thick, and preferably about 0.75 inch thick. The skin may be provided on a major flat face of the foam and the other face convoluted, or both faces can be skinned, or the foam layer may include two or more thicknesses of skinned flam. The garments provide better wind resistance than garments with simple, open-cell foam construction, and allow the selection of a wider variety of outer fabrics, while still having the desired moisture vapor transfer, insulation, and wind resistance properties. The skinned foam is also easier to handle, cut and sew during the construction of cold weather garments.

The third patent assigned to Burlington is U.S. Pat. No. 4,807,303 to Joe A. Mann, et al., which discloses upper and lower body cold weather garments which have excellent warmth, moisture permeability, wind resistance, and water resistance. The garment comprises an interior lining fabric, such as a loosely knit nylon lining, an outer fabric, and a layer of preponderantly open-cell foam of between 0.5 inch to 1.0 inch in thickness between an interior lining fabric and an outer fabric, with the three components being interconnected by stitching at the edges of the garment. The outer fabric has air permeability of less than 15, and preferably less than 10, cubic feet per minute per square foot at 0.5 inches head of water, and has moisture vapor transmission of at least 1,000 grams per square meter over a period of 24 hours. The outer, or shell, fabric is preferably woven from a fine denier, multi-filament, polyester yarn. The upper and lower body garments, when worn as the only cold weather protecting garments and without any other garments having poor moisture vapor transmission, provide extremely effective cold weather comfort, even in windy environments.

What is needed is an improved lightweight and compressible sleeping bag which incorporates the insulative and moisture vapor transmission qualities of the clothing designed by James G. Phillips and B. Dean Lassiter.

SUMMARY OF THE INVENTION

The present invention provides an improved sleeping bag having an open-cell, hydrophobic, polyurethane or polyether foam insulation layer sandwiched between an outer shell of fully-synthetic, tightly-woven, preferably rip stop, water-resistant, yet breathable polyester or nylon fabric shell and a more loosely-woven smooth fabric liner, also made of a smooth, fully-synthetic polymeric material, such as polyester. A preferred size for people up to 78 inches in height (about 198 cm) is 84 inches (about 213 cm)×34 inches (about 86 cm). In fact, even taller people can comfortably sleep in the bag by sleeping on their sides and bending their knees. The sleeping bag also has a longitudinal overlapping opening that extends the full length of the bag. Once the two sides of the opening are overlapped, the overlapping sides become secured together with a plurality of magnetic fasteners. Each fastener consists of a magnetic button component, which fits into a magnetic socket component of opposite polarity. Because the magnetic button components and the magnetic socket components are closely aligned with one another when the bag is stretched to its full length, the securing process is virtually automatic, as each button component is strongly attracted to its respective magnetic socket component. Each magnetic button component and each magnetic socket component is secured to its proper position of the opening by means of a female-threaded backing ring, which screws onto a male-threaded post at the rear of its associated button or socket component through an aperture punched through the shell fabric, the open-cell foam insulation layer and the liner fabric.

There is a hanging cord loop positioned near each end of the longitudinal opening which enables the sleeping bag to be hung, at either end, over a bathroom shower spigot to drip dry after it is washed. In order to speed the drying process, after the sleeping bag has hung for several hours and most of the rinse water has filtered down to the bottom edge of the bag, the accumulated water can be wrung out of that edge so that remaining moisture can evaporate more quickly. The sleeping bag also has a cord loop secured to each of the four inner corners thereof. A rectangular pillow, having open-cell form padding in a polyester fabric cover, has a noose secured to one of its four corners. can be secured to any of the four inner cord loops with a carabiner.

The sleeping bag is designed so that a person can sleep completely inside the bag, with the opening secured closed with the magnetic fasteners. The shell fabric, the open-cell foam insulation layer, and the liner fabric are all sufficiently permeable to atmospheric air that the person can breath easily and comfortably within the closed bag. The sleeping bag essentially becomes a sleeping cocoon. Respiratory moisture and perspiration are transferred to the exterior of the bag via the process of moisture vapor transfer through the liner fabric, foam insulation layer and the outer shell fabric. Those who have slept within the sleeping bag in such a manner have noted that initial mild claustrophobia is soon transformed into the most restful sleep of their lives. This is likely due to the fact that no exterior light seeps through the foam insulation layer, and the human body most effectively produces melatonin in the complete absence of light. A healthy dose of melatonin is known to be essential for the human body to enter the REM stages of sleep. What Is REM Sleep? Rapid eye movement (REM) sleep is a stage of sleep associated with dreaming and memory consolidation.

REM sleep was first discovered in the 1950s, when scientists studying sleeping infants noticed that there were distinct periods when their eyes moved rapidly from side to side. An individual's first REM cycle of the night begins about 90 minutes after falling asleep and recurs every 90 minutes. The eyes move around quickly behind the eyelids and brainwaves look similar to those of someone who is awake. During REM sleep stages, breathing, heart rate, and blood pressure rise to near-waking levels. REM sleep, often referred to as stage 5 sleep, is when the individual is most likely to dream. During this sleep stage, one's arms and legs become temporarily paralyzed to prevent that person from physically acting out his/her dreams and possibly injuring himself or others.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is front plan view of the new sleeping bag having open-cell polyurethane foam insulation and a center opening with magnetic fasteners;

FIG. 2 is a front plan view of the sleeping bag of FIG. 1, with the magnetic fasteners unfastened and the top and bottom flaps pulled apart, showing the interior of the bag;

FIG. 3 is a rear plan view of the new sleeping bag of FIG. 1;

FIG. 4 is a right-side elevational view of the new sleeping bag of FIG. 1;

FIG. 5 is a left-side elevational view of the new sleeping bag of FIG. 1;

FIG. 6 is top elevational view of the new sleeping bag of FIG. 1;

FIG. 7 is a bottom elevational view of the new sleeping bag of FIG. 1;

FIG. 8 is a cross-sectional view of the new sleeping bag, taken through section line 7-7 of FIG. 1, and shown at 2.5× scale; and

FIG. 9 is a cross-section view of the new sleeping bag, taken through section line 8-8 of FIG. 1, and shown at 2.5× scale; and

FIG. 10 is an enlarged view of the circular area 10 of FIG. 9.

PREFERRED EMBODIMENT OF THE INVENTION

The invention will now be described in detail with reference to the attached drawing figures. It should be understood that CAD drawings may not be the best medium to graphically illustrate a steeping bag made of cloth and foam, given that lines are too straight and curves too perfect. However, as the drawings are intended to be merely representative of the invention, they should be more than sufficient to convey an understanding of product and its method of fabrication.

Referring now to FIGS. 1, a preferred embodiment of the new sleeping bag 100 is shown, with the first and second upper surfaces 101-A and 101-B, respectively, of an outer fabric shell 101 visible. The fabric outer shell 101 is made of fully-synthetic, tightly-woven, optionally ripstop, waterresistant, yet breathable polyester or nylon fabric. A tightly woven fabric has no space between the threads. When tightly woven fabric is held perpendicular to the sun or other bright light, no direct light will be seen coming through the fabric. Ripstop fabric is a type of lightweight, waterresistant and extremely durable fabric made from polyester, nylon or natural fibers and specially designed to resist tearing and wear through its grid structure, with reinforcing, typically double-diameter threads woven at regular intervals, creating a checkered pattern which resists the spreading of small tears in the fabric. It is important to note that the outer shell fabric is water resistant, but not waterproof. A waterproof fabric is a fabric that unbreathable, and therefore unsuitable for use as the outer shell fabric. The ideal outer fabric shell has both a high water vapor transmission rate (WVTR) and low air permeability. Hydophobic coating of the fabric fibers of the outer shell fabric can improve waterresistance of the fabric. A tightly woven fabric reduces permeability of the fabric to air and wind, and also enhances its strength. Water vapor transmission rate, which is interchangeable with the term moisture vapor transmission rate (MVTR), is the amount of water vapor that passes through a substance or material over a specific period of time. A measure of breathability, Several international organizations, such as ASTM International (formerly the American Society for Testing and Materials), sets standards for the scientific community to follow with regard to measuring WVTR. The international standard of measurement is grams per square meter per day (g/m²/day). Air permeability is a widely used test which measures how easily air is passed through fabric and helps to indicate the fabric's breathability, particularly for wind-resistant, weather-resistant and waterproof fabrics. Air permeability, on the other hand, is defined by the ASTM as “the rate of air flow passing perpendicularly through a known area under a prescribed air pressure differential between the two surfaces of a material and is assessed by the volume of air in cubic centimetres (cm³) which is passed through 100 cm² of the fabric in one second at a pressure difference of 10 cm head of water.”

Still referring to FIG. 1, the sleeping bag 100 is of generally rectangular shape, having somewhat rounded corners. A preferred size for people up to 78 inches in height (about 198 cm) is 84 inches (about 213 cm) in length×34 inches (about 86 cm) in width. In fact, even taller people can comfortably sleep in the bag by sleeping their sides and bending their legs at the knee. Of course, the sleeping bag 100 can be made wider and longer, as needed. First and second longitudinal sewn seams 102-A and 102-B, respectively, and two end seams, which are not visible in this view, are used to position the inner foam insulation. A center longitudinal opening is provided by overlapping flaps, of which only the upper flap 103, which is continuous with the upper surface 101-A, is visible in this view. The lower flap is covered by the upper flap 103. The overlapping flaps are held together by multiple releasable, self-centering magnetic fasteners 104-A, 104-B and 104-C (generally 104). Three such fasteners are considered optimum for a sleeping bag of the presently preferred length. A hanging cord loop 105-A or 105-B is positioned near each end of the longitudinal opening which enables the sleeping bag to be hung, at either end, over a bathroom shower spigot to drip dry after it is washed. In order to speed the drying process, after the sleeping bag has hung for several hours and most of the rinse water has filtered down to the bottom edge of the bag, the accumulated water can be wrung out of that edge so that remaining moisture can evaporate more quickly. A shroud strip 106 extends from the upper flap 103 and consists of two parallel layers of the fabric shell 101 which are in contact one with another.

Referring now to FIG. 2, the sleeping bag 100 is shown with the magnetic fasteners 104-A, 104-B, and 104-C have been unlatched and the upper flap 103 pulled away from the lower flap 201, thereby exposing the fabric liner 202 inside of the sleeping bag 100. Compared to the fabric shell 101, the fabric liner 202 is a more loosely-woven smooth fabric, which is also made of a smooth, fully-synthetic polymeric material, such as polyester. In the context of textiles, “smooth” refers to the surface texture of a fabric or material. A smooth fabric is characterized by a lack of unevenness, giving it a sleek and polished appearance. Smooth textiles are highly desirable for their comfort, elegance, and versatility in various applications. Smoothness in textiles is achieved through different manufacturing processes and the choice of fibers. Fabrics made from fine and tightly woven fibers tend to have smoother surfaces compared to those made from coarser fibers. Silk, satin, fine cotton, rayon, and certain synthetic materials like polyester are known for their smooth texture. The smoothness of a fabric is often associated with several desirable properties. First and foremost, smooth fabrics feel pleasant against the skin, providing comfort and reducing friction. This makes them suitable for clothing items like shirts, dresses, lingerie, bedding, and in this case sleeping bag liners. Each of the magnetic fasteners 104-A, 104-B, and 104-C comprises a socket component 203 and a button component 204. The three socket components of 203-A, 203-B, and 203-C of magnetic fasteners 104-A, 104-B, and 104-C, respectively, are visible on the lower flap 201. Only the button component 204-B of magnetic fastener 104-B is visible on the upper flap 103. Button components 204-A and 204-C are covered by the upper flap 103 and are not visible in this view.

Referring now to FIG. 3, the underside surface 101-C of the new sleeping bag 100 is shown. The lower surface 101-C of the outer shell fabric 101 is continuous with the upper surfaces 101-A and 101-B, as the outer shell fabric 101 wraps around the rounded longitudinal sides 101-D and 101-E (shown more fully in FIGS. 4 and 5). As in FIG. 1, the hanging cord loops 105-A and 105-B are visible in this view.

Referring now to FIG. 4, the rounded longitudinal side 101-D of the sleeping bag 100, is continuous with the first upper surface 101-A of outer shell fabric 101 and the lower surface 101-C of the outer fabric shell 101 of the sleeping bag 100. The first upper surface 101-A is, of course, adjacent and continuous with the upper flap 103.

Referring now to FIG. 5, the rounded longitudinal side 101-E of the sleeping bag 100, is continuous with the second upper surface 101-B of outer shell fabric 101 and the lower surface 101-C of outer fabric shell 101 of the sleeping bag 100. The second upper surface 101-B is, of course, adjacent and continuous with the lower flap, which is covered by the upper flap 103 in FIG. 1. The exposed edge 501 of the upper flap 103 is visible in this view, as are hanging cord loops 105-A and 105-B.

Referring now to FIG. 6, and looking at the first end of the sleeping bag 100 from a vantage point to the left of FIG. 1, the first end seam 601 of the sleeping bag 100 is visible. The lines 602-A, 602-B, 602-C and 602-D are merely folds in the outer shell fabric 101. First and second longitudinal sewn seams 102-A and 102-B, respectively, are also seen in this view, as is the upper flap 103.

Referring now to FIG. 7, and looking at the end of the sleeping 100 from a vantage point to the right of FIG. 1, the second end seam 701 of the sleeping bag 1—is visible. The lines 702-A, 702-B, 702-C and 702-D are merely folds in the outer shell fabric 101. First and second longitudinal sewn seams 102-A and 102-B, respectively, are also seen in this view, as is the upper flap 103.

Referring now to FIG. 8, this cross-sectional view through section line 8-8 of FIG. 1 shows the interior 801 at the first end of the sleeping bag 100. Also visible is the open-cell, hydrophobic polyurethane or polyether foam insulation layer 802 sandwiched between the outer shell 101 and the fabric liner 202. The foam insulation layer 802 is continuous from the upper flap 103 to the lower flap 201. The hydrophobic nature of the foam insulation layer 802 enhances water vapor transmission through the foam insulation layer 802, as the foam repels water vapor condensation within the pores of the foam, thereby ensuring that the foam insulation layer does not act as a sponge. In a drawing of this size, there is a real problem of scale. A line has a thickness that is greater than the scaled thickness of the outer fabric shell 101 and the inner fabric liner 202. Thus, the open-cell foam insulation layer 802 should be represented by only the drawing's cross-sectional fill, which the fabric layers should be represented by the lines surrounding the cross-sectional fill. This convention has been applied by showing arrows pointing to the lines identified, respectively, as the outer fabric shell 101 and the inner fabric liner 202. Also visible in this view is the inner view of the first end seam 601, which includes two layers of the outer fabric shell 101, two compressed ends of the open-cell foam insulation layer 702, and two layers of the inner fabric liner 202. The view of the raw edges of the layers comprising the first end seam 601 are not visible because they are covered with a piece of the inner liner fabric, which is sewn as a wrap-around band along the first end seam 501. Also visible in FIG. 8 is a first pair of cord loops 804-A and 804-B at opposite internal corners of the first end of the sleeping bag 100. Both cord loops 804-A and 804-B are securely sewn into the first end seam 601. A foam-padded pillow (not shown), having a cord noose secured to one or more corners, can be secured to the inside of the sleeping bag 100 by interconnecting one of the nooses to one of the cord loops 804-A or 804-B with a carabiner clip (not shown). In order to maximize comfort of the user, the sleeping bag 100 should have a WVTR of at least 1200 g/m²/day when measured with an internal temperature of 27.2° C. (81° F.) and an exterior temperature of 4.44° C. (40° F.). When a temperature gradient exists, the transmission of water vapor will always be from the warm side of the gradient to the cold side. This means that water vapor is being transferred from inside of the sleeping bag 100, through the inner fabric liner 202, through the open-cell foam insulation layer 702, and through the fabric outer shell 101 to the exterior of the sleeping bag 100.

Referring now to FIG. 9, this cross-sectional view through section line 9-9 of FIG. 1 shows the interior 801 at the second end of the sleeping bag 100. This view also shows one of the releasable magnetic fasteners (in this case, 104-C) as a cross-section through its center. All three releasable magnetic fasteners 104-A, 104-B and 104-C are identical. FIG. 10 shows an enlarged cross-sectional view of releasable magnetic fastener 104-C. Also visible is the open-cell foam insulation layer 802, which is continuous from the upper flap 103 to the lower flap 201, which is visible in this view. The foam insulation layer 802 is sandwiched between the outer fabric shell 101 and the inner fabric liner 202. Also visible in this view is the inner view of the second end seam 701, which includes two layers of the outer fabric shell 101, two compressed ends of the open-cell foam insulation layer 802, and two layers of the inner fabric liner 202. The view of the raw edges of the layers comprising the second end seam 701 are not visible because they are covered with a piece of the inner liner fabric, which is sewn as a wrap-around band along the second end seam 701. Also visible in FIG. 9 is a second pair cord loop 804-C and 804-D at opposite internal corners of the second end of the sleeping bag 100. Both cord loops 804-C and 804-D are securely sewn into the second end seam 701. A foam-padded pillow (not shown), having a cord noose secured to one or more corners, can be secured to the inside of the sleeping bag 100 by interconnecting one of the nooses to one of the cord loops 804-A or 804-B with a carabiner clip (not shown). Thus the owner of the sleeping bag 100 can sleep with his head at either end of the sleeping bag 100.

Referring now to FIG. 10, this enlarged cross-sectional view shows the unique features of the releasable magnetic fasteners 104. Each releasable magnetic fastener 104 includes a magnetic button component 204 and a magnetic socket component 203. Both the magnetic button component 204 and the magnetic socket component 203 are secured to their proper respective positions of the opening by means of a female-threaded backing ring 1001, which screws onto a male-threaded post 1002 at the rear of its associated button component 204 or socket component 203 through an aperture 1003 or 1004 punched through the fabric shell 101, the open-cell foam insulation layer 802 and the fabric liner 202. A spring-loaded latch 1005 enables the magnetic button component 204 to axially latch into the magnetic socket component 203, but prevents axial unlatching. The magnetic button component 204 can be unlatched only by sliding it sideways out of the magnetic socket component 203 to the left in FIG. 10.

Although only a single embodiment of the sleeping bag, insulated with open-cell foam, and having a center opening securable with magnetic fasteners, has been shown and described, it will be obvious to those having ordinary skill in the art that changes and modifications may be made thereto without departing from the scope and the spirit of the invention as hereinafter claimed.

Claims

1. An improved sleeping bag comprising: an outer shell of tightly-woven, water-resistant, yet breathable fabric;an inner liner made of smooth fabric that is more loosely woven than the fabric of the outer shell;an open-cell, synthetic foam insulation layer sandwiched between the outer shell and the inner liner, said insulation layer, said outer shell, and said inner liner extending a full length of the sleeping bag;a longitudinal opening formed by overlapping opposite ends of the sandwich formed by the outer shell, the foam insulation layer and the inner liner;a plurality of magnetic fasteners which releasably secure the overlapping opposite ends together.

2. The improved sleeping bag of claim 1, where the fabric of said outer shell is made from at least one fully-synthetic material.

3. The improved sleeping bag of claim 2, wherein the fully-synthetic material from which the fabric of said out shell is made is selected from the group of polymers consisting of nylon and polyester.

4. The improved sleeping bag of claim 3, wherein the breathable fabric, from which said outer shell is made, is woven with a ripstop grid structure.

5. The improved sleeping bag of claim 1, where the smooth fabric from which the inner liner is made is selected from the group consisting of polyester, silk, and nylon.

6. The improved sleeping bag of claim 1, wherein said longitudinal opening extends up to the full length of the sleeping bag.

7. The improved sleeping bag of claim 1, wherein the open-cell, synthetic foam from which the insulation layer is made is selected from the group consisting of hydrophobic, open-cell polyurethane and hydrophobic, open-cell polyether foams.

8. The improved sleeping bag of claim 1, wherein the magnetic fasteners are self-centering.

9. The improved sleeping bag of claim 1, wherein when a temperature gradient exists with a temperature, within the sleeping bag, of 27.2° C. and a temperature of 4.44° C., external to the sleeping bag, the WVTR through the outer sheet is at least 1200 g per m2 per day.

10. An improved sleeping bag comprising: an outer shell of fully-synthetic, tightly-woven, water-resistant, yet breathable fabric;an inner liner made of smooth, breathable, fully-synthetic polymeric fabric, that is more loosely woven than the fabric of the outer shell;an open-cell, synthetic foam insulation layer sandwiched between the outer shell and the inner liner, said insulation layer, said outer shell, and said inner liner extending a full length of the sleeping bag;a longitudinal opening formed by overlapping opposite ends of the sandwich formed by the outer shell, the foam insulation layer and the inner liner;a plurality of self-centering magnetic fasteners which releasably secure the overlapping opposite ends together.

11. The improved sleeping bag of claim 10, wherein said longitudinal opening extends up to the full length of the sleeping bag.

12. The improved sleeping bag of claim 10, wherein the fully-synthetic material from which the fabric of said outer shell is made is selected from the group of polymers consisting of nylon and polyester.

13. The improved sleeping bag of claim 12, wherein the breathable fabric, from which said outer shell is made, is woven with a ripstop grid structure.

14. The improved sleeping bag of claim 10, where the smooth fabric from which the inner liner is made is selected from the group consisting of polyester, silk, and nylon.

15. The improved sleeping bag of claim 10, wherein the open-cell, synthetic foam from which the insulation layer is made is selected from the group consisting of hydrophobic, open-cell polyurethane and hydrophobic, open-cell polyether foams.

16. The improved sleeping bag of claim 10, wherein when a temperature gradient exists with a temperature, within the sleeping bag, of 27.2° C. and a temperature of 4.44° C., external to the sleeping bag, the WVTR through the outer sheel is at least 1200 g per m2 per day.

17. An improved sleeping bag comprising: an outer shell of fully-synthetic, tightly-woven, water-resistant, yet breathable fabric;an inner liner of smooth, breathable, fully-synthetic, polymeric fabric;a hydrophobic, open-cell, synthetic foam insulation layer sandwiched between the outer shell and the inner liner, said insulation layer, said outer shell, and said inner liner extending a full length of the sleeping bag;a longitudinal opening formed by overlapping opposite ends of the sandwich formed by outer shell, the foam insulation layer and the inner liner, said longitudinal opening extending up to the full length of the sleeping bag;a plurality of magnetic fasteners which releasably secure the overlapping opposite ends together.

18. The improved sleeping bag of claim 17, wherein the fabric of said outer shell is selected from the group consisting of nylon and polyester.

19. The improved sleeping bag of claim 17, wherein the synthetic foam insulation layer is selected from the group consisting of polyurethane foam and polyether foam.

20. The improved sleeping bag of claim 17, wherein when a temperature gradient exists with a temperature, within the sleeping bag, of 27.2° C. and a temperature of 4.44° C. external to the sleeping bag, the WVTR through the outer sheet is at least 1200 g per m2 per day.