Patent Application
20220296001
A typical human being spends almost one third of the time in bed. The sleep is a major human activity, in which energy is replenished and the body is allowed to rest. The deprivation of sleep has been linked to major human-related catastrophe and, in smaller scales, automobile accidents and lower work performance. One key element of sleep is to allow the body to rest. The key criteria for a good mattress are comfort, ventilation and spinal support. Comfort is related to minimizing the pressure points. In the early mattress design, various materials, including hay, were used to reduce the pressure points by providing more contact surface area. Ventilation is related to the climate in which the sleeper feels not too hot, not too cold, not too humid and not too dry. The subjective requirements for ventilation are for the most part taken care of by air conditioning in the room or in the bigger area of the house or apartment. Spinal support is related to allowing the spine to rest near its natural S shape. Unfortunately through the many decades of mattress design and development, spinal alignment has been for the most part ignored.
For many years, spring mattresses were the prevalent mattress design. Airflow was good in between the springs. A relatively thin layer of foam was placed on top of the springs and offered a reasonable comfort and overall very good ventilation. In recent years, memory foam has enjoyed great popularity because it enhances the support by cuddling the body. With the springs replaced by foam, the top layer memory foam having a low airflow and the overall mattress becoming thicker, such a mattress provides very good comfort at the expense of sacrificing ventilation. Worse yet, many sleepers complain sweating during sleep due to the memory foam “trapping the body heat”. Another complaint was that once the memory foam is warmed up by the body, the foam becomes so soft that the sleep feels like “having to dig” himself or herself out of the bed. Still, there has been no effort to improve spinal alignment.
The human spine provides the main support for the body, allowing the person to stand upright, bend and twist, while protecting the spinal cord from injury. The human spine can be divided into 4 regions: the neck (cervical), the shoulder (thoracic), the lower back (lumbar) and the buttock (sacrum and coccyx). Each region has different number of vertebrae: seven in the cervical region (labeled C1 to C7), twelve in the thoracic region (labeled T1 to T12), five in the lumbar region (labeled L1 to L5), five in the sacrum and four in the coccyx. Only the top 24 vertebrae are movable; the vertebrae of the sacrum and coccyx are fused. The vertebrae are relatively small in the cervical region, bigger in the thoracic region and still bigger in the lumbar region. These regions are of different height and have different support requirement. As an example, for an adult man of 5′9″ tall, the cervical region is about 5″ high, the thoracic region about 12.5″ high and the lumbar region about 7″ high. For a shorter person these dimensions will be proportionally smaller, and vice versa.
The human spine has a natural “S” shape, when viewed from the side. The neck and the lower back regions have a slight concave curve (curved in towards the front of the body), whereas the thoracic region has a convex curve (curved towards the back of the body). In the cervical spine, the angle of curvature is about 30-35 degrees and in the thoracic spine, the angle of curvature is about 30-40 degrees. In the lumbar spine, the angle of curvature is about 35-45 degrees. These curves help the spine withstand great amounts of stress. During the day, the discs in the spine become compressed from being upright. It becomes necessary to decompress the spine during sleep.
For this background discussion, it is constructive to define a few key terms. A typical mattress comprises a top surface and a bottom surface. There is a longitudinal direction, which is the direction from the head region to the foot region of the mattress. Perpendicular to the longitudinal direction is the transverse direction, extending on the top surface of the mattress. The third direction is the vertical direction, which is the direction from the bottom surface to the top surface. In a given mattress design for two users, there is a phantom longitudinal line separating the mattress into two halves. For example, in a queen-sized mattress, the length is 80 inches in the longitudinal direction; the width is 66 inches in the transverse direction. If a particular design allows for different firmness for each user, the mattress is described as having 2 sectors, each measuring 80 inches long and approximately 33 inches wide. Where height is discussed, the height is relative to the bottom surface of the mattress. For spinal support, the focus is on the foam firmness profile in the longitudinal direction. If the longitudinal dimension is divided into four equal-sized zones, each zone will be 20 inches long. For a mattress with multiple layers, the first layer is the top layer, which comprises a top surface that is the same as the top surface of the mattress.
The need for spinal support has been recognized in a few designs, mostly to create multiple zones in the mattress. U.S. Pat. No. 4,879,776; 5,077,849 and 5,111,542 all to Farley disclose creating 3, 5 or 7 zones. In the case a 3-zone design, it has proven not to be effective for spinal alignment, in that the shoulder and part of the lumbar region will be included in the first zone, where the remainder of the lumbar and the buttock region will be included in the second zone. Such a pre-determined inflexible zoning makes the mattress more uncomfortable than a single-zone mattress. U.S. Pat. Appl. 2017/0325596 by Torbet and 2015/0296993 by Boyd disclose a mattress which provides the user 9-12 transversely extended foam blocks per sector that has a softer side and a firmer side. However, such a binary selection of foam firmness is too limited, considering that sleepers have different body weight, body shape, and firmness preference. Also, it requires a heavy duty mattress frame, which adds significant cost and difficulty in shipping.
U.S. Pat. No. 6,684,433 to Giori discloses using an air bladder to change the mattress firmness. U.S. Pat. No. 6,687,935 to Reeder discloses creating multiple zones for a medical mattress. In U.S. Pat. No. 9,462,893, Ramano divided the whole body length into four regions and used four foam- cushioned air chambers to support the respectively four body regions. In U.S. Pat. No. 6,854,144, Mehring, disclosed the use of seven air pockets or foam blocks around the sacrum to reduce the pressure there to below the ischemic threshold of 30 mmHg. While this design may be successful in locally reducing the pressure at the sacrum and thereby minimizing the pressure ulcer there, it does not address spinal alignment, which involves body parts from the neck region to the sacrum region. In U.S. Pat. Appl. 2007/0157394, Giggleman uses multiple air pockets in an attempt to reduce the local pressure. However, the design is very cumbersome and the locations of the air pockets cannot easily be adjusted for users of different height and weight. In U.S. Pat. Appl. 2017/0156506, Torbet teaches the use of voids to reduce the pressure points locally in the upper body, the middle body and the lower body regions of the body. While the pressure points are reduced, these voids, as big as 2 inches deep and 5.5 inches wide, become the point of stress concentration and the foam around these voids starts to crack, causing premature fatigue. As this foam experiences excess stress, it becomes soft at an accelerated pace, making the foam too soft for supporting the body loading.
U.S. Pat. No. 6,398,199 and 6,966,091 both to Barber disclose using innerspring assembly with varying degrees of firmness, but he used only three zones. As discussed above, three zones are too few in number and therefore each zone is too big to tailor to the various spinal regions. U.S. Pat. No. 7,191,483 and 7,386,903 both to Hochschild disclose the use of mattresses with three zones in the longitudinal direction using replaceable similar-sized foam blocks to customize to different users' comfort requirements. Like Barber's design, each zone is too big at approximately 27″ long in the longitudinal direction, in contrast to the cervical, the thoracic and the lumbar region being approximately 5″, 12.5″ and 7″ long.
U.S. Pat. No. 7,036,173 to Gladney teaches a design of mattresses with multiple channels to receive inserts of different cushioning characteristics. While Gladney teaches a design of mattresses with multiple channels to receive inserts of different cushioning characteristics, the inserts “include one or more springs affixed within the channel”. Indeed, in the embodiment, he references the use of pocket springs. In this invention, no springs are used. Secondly, while Gladney discusses the use of multiple channels, the specifications and the drawings are limited to four or channels and inserts, with, the channels spread in the longitudinal direction. There are only two channels for the spinal region, which will not be able to conform to the spinal shape. Without focusing on the spinal region, his design produces comfort, but not spinal alignment. Thirdly, these channels are required to be pre-cut in the factory, for example by a router, at the pre-determined locations. These pre-determined locations will not be able to tailor to sleepers of different height. Lastly, his design prefers the use of a channel cross section that is rectangular, presumably to take advantage of easy manufacturing using a router. However, such a rectangular shape tends to allow the inserts to come off easily, for example during shipping the mattress. These disadvantages help explain why this design has not gained traction in the market place.
While the concept of multiple zones is sound, these efforts essentially failed to recognize that people have different needs for the locations and firmness of the zones, due to different body height, body weight, body shape, sleep position preference and tactile sensation. While there was mention and recognition that the different parts of the body, namely the shoulders, the lumbar and the sacrum regions, have different mass and different contour, none of the prior art addresses the fact that since users have different body heights, the location and dimension of the zones have to be customized. In many designs, such as in U.S. Pat. No. 4,879,776; 5,077,849 and 5,111,542 and 6,687,935, the designs presumably used the presumptive average height of the male population and the typical body region dimensions to determine the size of the zones of the mattresses. Such a one-size-fits-all design has not been well received by the consumers. Indeed, the negative consumer reception can be understood considering that for a seven-zone mattress, the third zone, which is for the lumbar region, is designed for a 5 ft 9″ tall man, but anyone taller or shorter than that height will have the zones and the associated firmness in the wrong regions, often causing discomfort instead of enhancing comfort. In other designs, such as U.S. Pat. No. 6,398,199, 7,191,483 and 9,462,893, the designs simplistically divided the longitudinal length of the mattress into three or four equal-sized zones. This design approach also suffers from the fact that the middle zone is used for supporting both the lumbar and the sacrum regions, which physiologically have different mass and therefore different foam firmness requirement. As mentioned above, for an adult man of 5′9″ tall, the cervical region is about 5″ high, the thoracic region about 12.5″ high and the lumbar region about 7″ high. For a shorter person these dimensions will be proportionally smaller and vice versa. It can be seen that a zone with a length of 20 to 27 inches will not be able to conform to these individual regions of the body. Once again, such a one-size-fits-all approach has not gained any traction in terms of consumer acceptance. In mass production of mattresses, these designs achieve the goal of manufacturing efficiency presumably at a lower cost, but overlook the individual needs for spinal support.
Three additional considerations highlight the need for a mattress with individualized spinal support. Firstly, during pregnancy, a woman's body shape and weight distribution change. Many women feel that side sleeping becomes more comfortable even if they have slept on the back for most of their life. Secondly, with the population becoming more obese, the body shape and weight distribution change. To lessen the pressure around the belly, some people prefer to sleep on the side. There are increasingly higher frequencies of partners sharing the same mattress but having different sleeping needs. Finally, as people become older, the need for a more supportive mattress increases to minimize back pain.
Since 2013, there has been a marked increase in all-foam mattresses being bought over the internet. An all-foam mattress may have one or more layers. A typical all-foam mattress core may comprise 3 layers—a top layer being a memory foam which offers pressure point reduction; a middle layer being a conventional foam with medium firmness which offers transition from the soft top layer to the firm bottom layer; a bottom layer being a conventional foam with high firmness which offers support. These three layers are typically glued together. The mattress core is inserted in a zippered cover which may be opened, for example, to remove the cover for cleaning. Such an all-foam mattress has gained popularity because of the convenience of ordering online and it can be shipped conveniently. Added to its popularity was the fact that the mattress producers often offer a 90-day free trial and hassle-free returns. While such hassle-free return policy has been very well received by the consumers, it also creates a situations of high mattress returns, reaching as high as 4 to 9% depending on the individual brands. Many of the returned mattresses were donated to the homeless but others ended up in landfills. If a fraction of these mattress returns can be minimized by improving the consumer satisfaction, it will have a positive impact on waste reduction in our society.
While the memory foam has gained popularity because of its ability to improve comfort by reducing pressure points, it has a tendency to “trap the body heat”. Indeed, over 60% of the users cite poor body-heat ventilation as the top complaint for all-foam mattresses. In U.S. Pat. No. 9,326,616 discloses using a motorized air supply at the inside base of the mattress to heat or cool the mattress. In general a motor is less than 100% efficient, resulting in some of the electrical energy being wasted and turning into heat, which is trapped inside the mattress, which is essentially a foam-sealed enclosure. Such waste heat not only adds to the cooling burden of the mattress, but also creates motor noises which could disturb the user's sleep. In the design of '616, the air will flow out of the air supply located at the base of the mattress, up the vertical conduits, past a coil spring layer, and through small-diameter apertures in a so-called ventilation foam layer, but dead-ends into a top foam layer. Because the top foam layer is not specified to be high airflow, it blocks the air from reaching to the user's skin. Given that both the ventilation foam layer and the top foam layer use polyurethane foam, which is a good heat insulator, this design does not cool the user's skin efficiently.
It is generally recognized that body temperature plays a key role in having a restful sleep. Ideally, the body prefers the body temperature to drop slightly in order to fall asleep initially. This slightly lower temperature needs to be maintained within a certain range to minimize turning and tossing, which disturb the sleep. In nature, insects use spiracles to deliver air directly into their tracheal tubes. The spiracles are essentially airflow channels and can be opened or closed in an efficient manner via muscle relaxation or muscle contraction. To our knowledge, such a biomimic approach to improving the sleeper's ventilation has not been explored in the prior art.
It is therefore highly desirable to construct a mattress that offers individual spinal alignment while maintaining a high efficiency in production and shipping.
This invention features method of producing a mattress foam core which comprises a plurality of transversely extended foam rods that were cut during the mattress production process.
These transversely extended foam rods typically have a cross section of a convex shape, including but not limited to triangles, squares, rectangles, circles, ovals and hexagons. These transversely extended foam rods can be replaced with foam rods of different firmness, creating more than 10 zones with varying firmness in each zone thus tailoring to the user's needs, adjusting for their differences in height, weight, sleeping position, and comfort preference. In sum, these zones may be configured to improve the user's spinal alignment.
The transversely extended replacement foam rods typically have cross sections that are substantially the same shape as the pre-cut foam rods, but may also be of different shape. In one embodiment, the transversely extended replacement foam rods comprises foams of two or more different firmness in the transverse direction, thus allowing the mattress to be customized for multiple users with different sleeping needs. In another embodiment, the first foam layer and the replacement foam rods each comprise vertically and transversely extended apertures the locations of which allow the corresponding apertures to form a network of airflow channels to provide additional cooling around the user's body.
The pre-cut foam rods are shown with a cross section of ovals 22-24 and trapezoids 20, 21, 25-38, and have an un-even spacing.
Disclosed herein is an all-foam mattress, which comprises 1 or more foam layers, an outer cover with a zipper and a plurality of pre-cut transversely extended foam rods. When more than one layer is used, the layers may have different foam firmness and are typically glued together. During the mattress production process, transversely extended foam rods are cut, for example using a CNC contour cutter and other similar cutting process known to those skilled in the art. These transversely extended foam rods are cut at various locations in the longitudinal direction of the mattress. These transversely extended foam rods cover the neck, the shoulder, the lumbar, the sacrum and the tight regions of the body. Using body anthropometric data, the pre-cut foam rods are spaced by an average of about 2.5-3.5 inches apart, center- to-center. In general, the foam for the shoulder region should be of medium firmness to allow the shoulder to “sink” slightly into the mattress. Likewise, foam for the sacrum region should be firm to keep the body from hammocking.
About ⅔ of the population prefers to sleep on the side, while there is no single recommendation from the medical professionals on whether any one sleeping position is best for the body. Some people switch from one position to another, reflecting a change in personal preference. A mattress based on this invention will typically have more than 10, preferably 12 or more, transversely extended pre- cut foam rods. This number of transversely extended pre-cut foam rods will cover a length of 30 inches to more than 42 inches in the longitudinal direction of the mattress and should be able to accommodate the typical user, male or female, whose height ranges from 2.5 percentile to 97.5 percentile.
In this invention, the transversely extended foam rods are pre-cut, but are left in the mattress and shipped to the user. The pre-cut foam rods may have a cross section of any shape. In one embodiment, the pre-cut foam rods have a cross section of a convex shape, including but not limited to triangle, square, rectangle, circle, oval, and trapezoid. The convex-shape cross section has the benefit of easy to cut on a CNC cutter, easy to remove from the mattress and easy to re-install the similar-shape replacement foam rods. The cross section of the pre-cut foam rods is chosen to ensure that the pre-cut foam rods will stay in place after the mattress is compressed, shipped to the user and allowed to expand. By taking out the pre-cut foam rods and inserting the replacement foam rods, the user can adjust the firmness at various locations tailoring to his/her personal preference on comfort, support and ventilation.
In another embodiment, there are two users and a pre-cut longitudinally extended pre-cut foam rod was included.
In another embodiment, the user can periodically replace the worn-out foam rods with new ones, thus in essence extending the useful life of the mattress.
In another embodiment, the replacement foam rods may be bigger than the pre-cut foam rods, thereby rising above the t top surface of the mattress.
In still another embodiment, the replacement foam rods may be smaller than the pre-cut foam rods. By having a smaller cross section, these smaller-than-pre-cut replacement foam rods create additional softening effect.
In another embodiment, the replacement foam rods are pre-heated, for example in a microwave, or pre-cooled, for example in a freezer or refrigerator, prior to sleep. Given that the replacement foam rods are small in dimensions relative to the whole mattress, it is energy-efficient to adjust the replacement foam rod temperature outside of the mattress. As an illustration, the replacement foam rod can be wrapped inside a plastic bag and placed inside the microwave or refrigerator, for a short time before use, to achieve the target temperature.
The pre-cut foam rods can be located in any layer in the mattress. In a preferred embodiment, the pre-cut foam rods are located in the top layer of the mattress, where the benefits of adjusting for sleeper's comfort and support are felt more directly. To access the pre-cut foam rods, the user will unzip the cover and lift off the top half of the said layer, and lift a particular pre-cut foam rod off substantially vertically. To replace the foam rods, the user will lay the replacement foam rods substantially flat on its designated position and push it in by applying a downward force with his/her fingers.
In one embodiment, the pre-cut foam rods are located in both the top layer and the bottom layer of the mattress, essentially doubling the impact of adjusting the firmness in each zone. The locations of the pre-cut foam rods in the top layer may be but are not limited to be a mirror image of the locations of the pre-cut foam rods in the bottom layer. Also, the dimensions and the depths of the pre-cut foam rods in the top layer can be but are not limited to be a mirror image of the dimensions and depths of the pre-cut foam rods in the bottom layer.
In the invention, it is contemplated that the foam mattress may be an all-foam mattress or a hybrid mattress. The mattress and the replacement foam rods can be made with polyurethane, latex, polyethylene, polystyrene, gel or other foam plastic.
