Beds – Mattress – Having confined gas
Reexamination Certificate
2002-06-05
2004-02-03
Luu, Teri Pham (Department: 3673)
Beds
Mattress
Having confined gas
C005S710000
Reexamination Certificate
active
06684433
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a pressure adjustable foam support apparatus and to a method of producing a body supporting structure with adjustable levels of density and firmness (IFD) simulating those of viscoelastic foam or latex foam.
BACKGROUND OF THE INVENTION
Recently, high density viscoelastic foam has been used in mattresses, mattress toppers and support pads. This material, which was originally developed for NASA, exhibits a slow recovery time after an external pressure is applied to it. Viscoelastic foam products are intended to conform with the contours of the user's body and provide improved comfort and support. Unfortunately, conventional viscoelastic foam presents a number of disadvantages. Due to its high density (typically in excess of 3 lbs/ft
3
), this material is quite bulky and heavy. A standard viscoelastic pad typically weighs approximately 3-4 times as much as a comparably sized standard, low density polyurethane foam pad. This makes the high density foam quite difficult and inconvenient to handle, transport and maneuver. The viscoelastic product is also considerably more expensive, about 3-5 times more expensive at the manufacturing level than low density polyurethane foam. Furthermore, conventional viscoelastic foam is not pressure adjustable to meet the individual user's needs, since it's cell structure is so tight that it is difficult to deflate, self-inflate, or pass air through the cells. Moreover, if air is vacuumed from a visco foam core, this foam will typically densify rapidly, and become uncomfortably hard.
Various self-inflating and pressure adjustable foam mattresses have been developed. See for example, Lea et al., U.S. Pat. No. 3,872,525, Nissen, U.S. Pat. No. 5,023,133, Bridgens, U.K. Patent No. 984,604 and my previous U.S. Pat. No. 6,038,722. To date, these devices have been particularly designed for outdoor and recreational use. None of the self-inflating mattresses or cushions are suitable for use in conventional indoor, bedroom or healthcare applications. For example, the Lea product is very thin and employed primarily as a camping mat. It is difficult to successfully adjust the pressure in the Lea mattress or to provide for desired levels of comfort because of the relative thinness of the item. If a user is lays upon the Lea mattress with the valve open, the foam cushion fully deflates almost immediately because the mat is very thin (i.e. 2″-3″). It is very difficult, if not impossible, to adjust the pressure and comfort level in either this or the other known products. A user lying on a mat of this type is simply unable to accomplish this. In fact, to date, self-inflating polyurethane foam mattresses have been utilized in only a fully inflated or fully deflated condition. Intermediate air pressure adjustment has not been exhibited in any of these devices. Nor has pressure adjustment been exhibited to date in any indoor foam mattress, mattress topper or healthcare mattress.
There is a good reason that pressure adjustability has not been a factor to date in the design of self-inflating foam filled mattresses. Pressure adjustability is most important for mats, mattresses, topper pads and healthcare mattresses that are designed for indoor use (e.g. beds, mattress toppers, sofas, sofa beds, hospital beds, furniture, etc.). Such support structures are usually relatively thick in order to provide the needed support and comfort levels desired by most persons. Deflating a thick foam pad according to the teachings of the above cited prior art would require super-human strength, as well as wasted time and effort. This has made the use of self-inflating foam impractical for indoor use to date.
Persons desiring custom pressure adjustment have been limited to the use of air bladder mattresses with the mandatory addition of foam layers or mattress covers superposed on the air bladder's surface to enhance comfort. Sleeping directly on the surface of an air bladder would be very impractical since when fully inflated, it would have sufficient support but feel very hard. Deflated or partially deflated, the bladder would lack the support needed to get a perfect night's sleep. These types of air bladder structures do not employ foam and do not provide the support, comfort and conformance with the body that is provided by traditional foam, visco or latex foam layers. Air bladders typically fail to keep support when they are deflated or partially deflated and the superposed foam layers above the air bladder also lose support, giving the person the illusion that the surface beneath them is changing firmness. Hence, air bladders gain or lose support, whereas foam, when partially deflated, becomes softer due to a decrease in indentation force deflection (IFD). At the same time the foam maintains support due to an increase in density within the foam core. Notwithstanding this, pressure adjustable foam has not been employed previously due, at least partly, to the problems and limitations described above.
SUMMARY OF INVENTION
It is therefore an object of the present invention to provide a foam support apparatus that is conveniently pressure adjustable to achieve comfort and support qualities comparable to those of a viscoelastic or a latex foam product.
It is a further object of this invention to provide a pressure adjustable foam support apparatus utilizing a low density foam which functions comparably to viscoelastic foam, but which is much less expensive, much lighter weight and far easier to handle than any viscoelastic support surface, or conventional box spring mattress.
It is a further object of this invention to provide a foam support apparatus that is more comfortable and versatile than any other standard, non-adjustable, comparable density, foam core mattress, mat or mattress topper existing to date.
It is a further object of this invention to provide a foam support apparatus that is quickly and conveniently pressure adjusted to provide multiple desired levels of density, pressure relief and firmness so that the user's individual comfort and support needs may be satisfied.
It is a further object of this invention to provide a pressure adjustable foam support apparatus which may be partially or fully inflated/deflated and collapsed in a quick and convenient manner by a single person using very little time, effort and exertion.
It is a further object of this invention to provide a pressure adjustable foam support apparatus that is quick, convenient and virtually effortless to assemble, disassemble, transport and store.
It is a further object of this invention to provide a pressure adjustable foam support apparatus that is airtight, impervious to gasses and fluids and which may be washed, pressure cleaned, or directly immersed in water.
It is a further object of this invention to provide a pressure adjustable foam support apparatus that, in certain embodiments is conveniently foldable in distinct sections so that said apparatus may be raised or reclined, as needed and the separate sections may be pressure adjusted utilizing the technology contained herein.
It is a further object of this invention to provide a pressure adjustable foam support apparatus that continuously and sequentially adjusts the pressure within various sections of the mattress so that prolonged engagement of the mattress with the skin and resulting bed sores are avoided.
This invention results from a realization that a relatively low density self-inflating polyurethane foam may be pressure adjusted so that it exhibits a density and firmness comparable to a much more expensive, heavier and non-adjustable viscoelastic or latex foam product. In particular, air is exhausted from or added to the low density foam such that the cellular structure of the foam is modified from its original cellular configuration. By decreasing the volume within the core and, hence, drawing together the cellular structure, this agglomeration of cells increases in density (support) and the firmness (softness/hardness) or indentation force deflection (I
Giori Gualtiero G.
Giori Janine
Conley Fredrick
Luu Teri Pham
Noonan William E.
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