CA2113320A1

CA2113320A1 - Inflatable air mattress and pillow incorporating novel variable tension-response internal structural systems

Info

Publication number: CA2113320A1
Application number: CA002113320A
Authority: CA
Inventors: Alan Brian Gancy
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-01-21
Filing date: 1994-01-12
Publication date: 1994-07-22
Also published as: US5608931A; US5852839A

Abstract

An inflatable air mattress is designed so as to provide increased comfort during use through the employment of a novel variable tension-response internal structural system. The novel tension-response is achieved through the appropriate parallel-coupling of individual rubber bands. The uninflated mattress occupies minimal storage and shipping space, and is lightweight. An inflatable air pillow, having different userresponse requirements from that of a mattress, employs a novel variable tension-response internal structural system consisting of series-coupled rubber bands. The uninflated pillow occupies minimal storage space. Parallel-coupled rubber band units can be combined in series-coupled units to produce special effects in other applications. The novel tension-response systems can also be constructed into 2- and 3-dimensional embodiments, for mattress, pillow, and other applications.

Description

2:~133~ `
, INFLATA~LE ~IR ~I~TTRESS ~ND PILLOW INCORPOR~TING NOVEL ~RIABLE
TENSION-RESPONSE INTERNAL STRUCTURAL SYSTEMS

Prior ~rt Currently, there are four types of bed mattress available.
One is the conventional steel-spriny mattress. It requires considerable storage and shipping space, and large warehousing and showroom retail space. Thus, the relatively low cost of mass-productlon manuEacture is offset by requirements of space.
Conventional mattresses can be unsanitary, and there are State laws which prohibit the sale of used mattresses. Within the home, and in institutions, the conventional mattress is heavy and cumbersome. All such mattresses require periodic "turning,"
which ls a nuisance for all users, but especially to those whose physical strength is limited.
There is not a wide range of response options, or "irmnesses" for conventional bed mattresses. For some users, even the softest available mattress is not comfortable, especially when sleeping on one's side. The firmer the mattress, the longer its life. Thus most hotels and motels supply very firm mattresses. These are found unsatisfactory to a large fraction of travelers and tourists worldwide.
Disposal of discarded conventional bed mattresses poses an environmental problem. Overall, the conventional steel-spring bed mattress does not satisfy the users' needs very well.
The second general type of bed mattress comes in the form of a rectangular block of "foam" material. ~his inventor has developed improvements in the foam mattress. Indeed, there are several recent inventions whereby the foam block is appropriately slotted to provide improved response to the user. Whereas the foam device so`lves some of ~he problems of the conventional mattress, it is still cumbersome, and possesses the same space requirements as the conventional mattress. In the current market, foam devices only represent a small fraction. It should be mentioned that foam pads, or "toppers~' are widely used in the internal construction of conventional mattresses.
The thlrd type of mattress is the waterbed, and this device .

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"! ~ , 2~:~332a - l~C~ 2 is ~ _~ff~y in popularity. The waterbed ~t~ represents a smaller fraction of the market than the conventional spriny mattress. The opinion oE users is sharply spliti there are those who enjoy the waterbed, and those who have tried them but definitely do not lilce them. The waterbed mattress, when not yet filled with water, potentially alleviates the problem oE space requirement which characterizes the conventional mattress. But once filled, the waterbed is obviously heavy and cumbersome.
Special bed construction is required to support the waterbed mattress. Even building construction must be checked to see if the floor will support the weight of the total waterbed. Other special features are required, such as an internal heating device to bring the massive amount of water up to a comfortable temperature. A large number of improvements in the internal workings of a waterbed mattress, e.g., baffles, have been patented in recent years.
Waterbeds have not yet seen application in institutional settings such as hospitals. Nor are they widely used in hotels and motels. They are obviously unsuitable for camping use. Thus the waterbed will most probably never represent more than a small fraction oE the total bed mattress market.
The smallest fraction of the bed mattress market is represented by the inflatable air mattress. It solves the problem of storage and shipping space. These devices are also lightweight and sanitary. Air mattresses mostly have camping and specialty use, however. The reason is that their response characteristics are unsatisfactory. The~ do not provide -the comfort level required for widespread use. The shape of such devices is maintained by a ne-twork of internal ~affles permanently attached to the internal walls of the inflatable air bag. These baffles are manufactured from the same or similar material as the bag itself, i.e., non-rigid plastic. When the device is inflated for use, it exhibits a "hardness" or rigidity which is ultimately attributable to the non~elasticity of the bag and of the internal baffles. Such an unsatisEactory response cannot be eliminated by under-inflating the air bag, as this results in an unstable response characterized as a "wobble."
What is needed is an inflatable air mattress, and an air pillow, which has elastic internal baffles or support structures.
But whereas the normal response characteristics of rubber bands or strips may be satisfactory for pillows ~vide inEra), they are unsatisfactory for mattresses. In fact, the normal response characteristic of a rubber band or strip is ~ust the opposite of what is required in a comfortable alr mattress.
The ideal solution would be a mattress which would be comfortably soft and responsive to a small child or light weight adult, yet supportive and stable enough for a heavy adult. Then there would be no need to market a "soft" mattress Eor children, ~' ~, 2~32~ `

ane adults who prefer them, and ~firm~ products to those other adults who need to experience an initial softness ~ollowed by a firmness with stability. Instead, a single unit would be sold to suit all tastes.
The present invention satisfies the unique requirements of inflatable air mattr~sses and pillows.
Backqround of the Invention The central feature of the invention is the response characteristic of lYhat is commonly known as a rubber band, when appropriately coupled in novel ways. A rubber band is a single continuous loop of rubber strip having a uniform - and normally rectangular - cross section. The term ~rubber band," or "band"
will be used in the Specification and in the Claims, although it should be understood that other embodiments are covered under the invention. For example, thin strips of rubber cut from a sheet, and with holes cut at each end, through which tension can be applied, represents one alternative embodiment. Rubber bands or strips represent forms of the so-called tension-response device.

~ When a rubber band is tensed, or "pulled," the response ¦ characteristic is as shown in Figure 1, Curve A. The band ; lengthens in direct proportion with the tension, in the low tension region; with increasing tension, there is a departure from linearity, and the band stretches as if it were a weaker band than the one originally acting. In a sense this is true, because as the the band is elongated, its cross section begins to diminish. ~ `~
~ In general, the greater the cross section of a band, the

3 "stronger" it will be. Thus, in Figure 1, Curve A represent a ~'weaker~ band, with a high initial slope to the curve. Curve B
represents the same initial lenqth of band, but with greater cross section. Note that the initial slope of the curve is -smaller than that for Curve A. ~ ;
The type of response just described will hereinafter be called the Normal Response. Such a response characteristic may be useful in one embodiment of the invention, that of the bed pillow, where rubber bands constitute the internal baffle or support system for a pillow-shaped air bag.
Where a rubber band is repeatedly ten~ed and release~ in application, the rule of thumb according to manufacturers is not to stretch the band beyond 200% of its "rest" length. Operating beyond this limit shortens the working life of the band. In the present invention means are provided to prevent thls Erom happening. Note that with real rubber bands, nonlinearity oE
response sets in before the 200% point is reached.
~I The Invention The Parallel-Band Variable Response System There are applications of the rubber band for which the ,.
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nor l response is undesirable. In Eact, just the reverse of the Normal Response is called for. I have discovered what I call a Variable Response pattern, the main feature of the invention, which responds to this need. This new concept will be intrcduced as follows: Suppose it were desired to utilize only the linear part o~ Curve A (or Curve B) in Figure 1. This can be done by placing in parallel with the rubber band a continuous loop of some non-stretch material such as a loop of nylon cord, or even a metal hook. This non-stretch loop would be sized to prevent the rubber band from stretching beyond a predetermined limit, in this case, bPyond the linear response segment of the response curve.
Such a device I have called the Limit ~and.
The particular application of the Limit Band, as just described, converts the Normal Response to a Linear Response. At the same time the Limit Band prevents the rubber band from exceeding its 200% stretch limit.
It should be obvious that the length of the Limit Band is always greater than the "rest length~ of the rubber band.
But now suppose the Limit Band is not made of non-stretch material, but instead is another rubber band. Now there are two rubber bands acting in parallel, one longer than the other. The response curve will, in general, be the opposite of the Normal Response pattern, with the couple becoming "stronger," to a point, the further it is tensed.
Imagine now that two or more rubber bands are coupled in parallel, in a continuous gradation of "rest" lengths. The response characteristic is shown as Curve C in Figure 1. The initial response is "sensitive" in the sense that a small amount of tension causes relatively greater stretching. As the t'ension continues, the band couple stretches relatively less. This is the Variable Response system referred to earlier.
The Variable Response System now fulfills the needs that have heretofore not been met. For example, when a set of band couples constitutes the internal baffle system for an inflatable air mattress, it is highly desirable that the initial response be "soft," whereas the more tensed system responds as "firm.~ As an illustration, the mattress should be comfortable for the child or very light weight adult who uses it. Such a body should slightly ~sink in~ to the mattress for greater comfort. Yet the same mattress should be firm enough to support a heavy adult; such a body experiences the comfortable "sinking in" feeling, yet also enjoys support. In other words, this body does not sinlc in excessively. The Variable Response sy~tem makes it possible to provide a single mattress for both children and adults, and avoid the necessity of customizing one mattress type to be marketed to adults only, and another to children only.
The series of bands of increasing length, which constitute the parallel coupliny, may be supplemented with a Limit Band of 2~13~
nc ~tretch material such as nylon or metal. Thus the slope of Curve C in Figure 1 becomes smaller as the coupling is stretched, finally ending in a slope of virtually zero as the Limit Band is encountered. Such a Limit Band can be important whenever there are limitations to the physical dimensions in application, such as, for example, the thickness of an inflatable air mattress.
` The Limit Band will also be important as regards saEety in some applications.
` Within the band couple, any variety of cross section of individual rubber bands may be employed. For example, all bands can have the same cross section. An even more dramatic variable response pattern is obtained when the longer bands in the couple are also of greater cross section. It is even feasible to use i smaller cross section bands as the longer ones in the couple; the reason is that even these "weaker" bands increase the strength of the coupling as tension is increased. The latter option, although feasible, is generally not desirable because the ; variable response nature of the coupling is diminished Figure 2 depicts a Variable Response parallel coupling, ! including a Limit Band. The Limit Band is si~ed to prevent the shortest band in the coupling from stretching past its 200%
limit. - -The Series Variable Response System I have discovered yet another means of converting a Normal Response, or even a Linear Response system to a Variable Response system. This is achieved through the series coupling of rubber - `
bands, in which the Limit Band can play an important role. The series system simply couples stronger with weaker bands. The weaker bands can be parallel-coupled with Limit Bands so that they don't become stretched excessively. In this sense the invention constitutes the series coupling of parallel-coupled units.
Figure 3 depicts the Series Yariable Response system.
As the series is tensed, the weaker bands stretch mainly first, providing a "softj" or sensitive response. With further tension, this stretching ceases due to the parallel Limit Bands associated with the weaker bands. Then the stronger bands come into play with further tension.
There is one important distinction between the parallel- and series-band concepts. In the parallel coupling, the shortest bands are activated first upon tensing, with no reaction at all by the longer bands; the latter are not activated until the shorter bands stretch to meet the longer ones. But in series coupling, all bands are activated as soo~ as tension is applied.
It is just that the weaker bands s-tretch relatively more, at least at first.
The series coupling concept i9 useful when a greater distance between tensing points has to be spanned. There is ,......... .

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th- ;etically no limit on the number of (short) rubber bands which can be linked together. To be sure, such distances can theoretically be spanned using a single parallel-coupliny of very long rubber bands, or strips. The series coupling is useful when such long rubber bands or strips are not available.
Bands can be linked in series using metal rings, plastic rings, or nylon cord, all which function as couplers. They can also be looped together, as shown in Figure 9.
The response of the series-coupling system is in principle the same as that of the parallel-coupling system, as shown by Curve C, Figure 1.
Combinations of Series- and Parallel-Couplin~ Systems Parallel-coupled rubber band systems, with or without Limit Bands, can be Coupled in turn as units of the Series-coupled chain. There is enormous variety possible in the types of component units used in such systems, as well as in their physical placement in the chain. This will be illustrated in the examples.
~ Two-Dimensional systems 3 Parallel-coupled systems, already described in one dimension, can also become components of two-dimensional networlcs. Figure 5 illustrates some of the ways in which this can be done. Figure 5A shows the~"woof" chains physically tied to the "warp" chains. But Figure 5~ shows woof and warp chains which are "woven" together. An e~en simpler arrangement, not depicted, is an overlay of woof sets onto warp sets. Figure 5D
shows a preferred-direction response system using rigid links. -It should be obvious that series-coupled bands can also be assembled in the various ways already discussed, to form two-dimensional networks.
If small enough rubber bands are used, a virtual "fabric"
~ can be produced. Into this fabric can be designed a great -1 variety of responses. In this sense, any desired "shape~ of tensed fabric can be achieved, one that "bulges" in the middle, or at any number and placement of points within the fabric. This represents the type oE response in which the perimeter of the Eabric is held rigid, as in a firemen~s safety net, or a hammock, and the distortion of the Eabric is due to the weight of an object or body on the fabric.
Another utility of the two-dimensional fabric is as a bafEle inside an airbay mattress, where the perimeter of the ~'fabric"
is fastened to the inner perimeter of the airbag. The fabric controls the shape of the alrbag dimensions. In this case the perimeter is not help rigid the same way a firemen's net is; but the perimeter is free to move somewhat depending upon -the weight of the person lying on the mattress. In this case the conformation of the perimeter is a combined function of the ~, pe ~ ~n~s weight, the air pressure within the bag, the shape of the bag itselE, and the nature of the two- dimensional Response System baffle. Figure 6 illustrates the mattress application.
~ Three-Dimensional Systems j The natural extension from 2-dimensional response systems is to 3-dimensional ones. One application is, again, to the airbag mattress. In this instance the 3-dimensional baffle is attached to the 3 dimensions of the inner surface of the airbag, not just at the perimeter.
~ Examples ;' I. Parallel Coupling oE Bands ~I To express couplings symbolically, let 1,2,3,4 stand for the s four band strengths (cross sections) available, in increasiny order of strength. Then let the symbols A,B,C,D stand for the increasing lengths of the bands. Thus the symbol lA represents the shortest, weakest band; 4D represents the longest, stoutest band, etc. Some examples of couplings are therefore:
(lA,lB,2C); (2A,2C); (lA,3C); (3A,3B,3C,3D); (2A,2B,2C,2D);
(lA,2B,3C,3C); (lA,lB,lB,2C); (2A,2A,4C,4D); (3A,3B,4C,4D);
(lA,2A,3B,4B); (lA,2B,3C,4D); (2A,3C,4D). There are many ~! additional possible combinations not shown. Note one feature of the combinations is there must exist at least two different lengths in each parallel coupling For there to be a Variable Response. There can be as many as four in the present example.
As for strength, all Eour bands can have the same strength. Or all four can have differing strengths. Limit Bands may be required in some applications, in order to place a check on the stretch of the shortest band in parallel.
Band lengths cannot be coupled indiscriminately 'in the parallel-coupled unit. For example, iE the longest band in a coupling has a rest length greater than twice that of the shortest band, then it cannot participate with the shorter band in producing the desired variable response. The reason is that the shorter band will be stretched beyond its 200% limit before the longer band b~gins to participate, and this is obviously .Js unworkable. The rule must therefore be made that the longest band in any group of parallel-coupled rubber bands must be shorter that twice the rest length of the shortest band in that group.
.. '- II. Series Coupling of Bands Using the same symbolism as in Example I for parallel couplings, add the "-" symbol to indicate joining together oE
individual bands or parallel couplings in a series. Thus, -lA-lA-2B-2A-3C-4A~ represents a series coupling of weaker and stronger individual bands, with no parallel couplings included.
Note that all but perhaps the strongest band requires a Limit Band in parallel with it. I'he series -(2A,2C)-3B-(lA,lB,2C)-4C~
represents a series grouping of single bands and parallel ~., ~!
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cou ~ings. Limit Dands are used for all but the strongest unit, and even it may employ a Limit band in parallel with it.
All of the following yield the Variable Response:
A. All Lengths Equal, But Strengths Differ -3B-3B-4B-2B-lB-2B-B. All Identical Parallel Couplings -(lA,2~,3C)-(lA,2B,3C)-(lA,2B,3C)-C. Not All Parallel Couplings Identical -(lA,2B,3C)-(2A,3B,3B)-(lA,2B,3C)-(2A,3C)-In this case there are two sources of l! variable response I working simultaneously: a) that due to any one or more of the parallel couplinas, and b) that due to the series connection oE
more tha,t one strength coupling.
D. All Identical Parallel Couplings, With All Identical Series Units -(2B,2C)-9D-(2B,2C)-~D-(2B,2C)-~D-E. Parallel Couplings All Identical, Series Units Different i, -(2B,2C?-3D-(2B,2C)-4D-(2B,2C)-9B-F. Parallel Couplings Differ, Series Units Identical ~
-(2B,2C)-3D-(lA,2B)-3D-(2B,2C)-3D- ~-G. Parallel Couplings Differ, Series ~nits Differ -(2B,2C)-(3A,4C)-4D-lB-H. Series Units Have Different Lengths, Different Strengths -lA-4D-3B-2A-4D-4D-3A- `
The above Examples illustrate the many ways that bands may be ~ -combined to achieve unique effects of Variable Response, whether employed in the one-dimensional cases actually symbolized, or ~;
whether they are combined in a 2-dimensional or even a 3-dimensional mode.
Application To Inflatable Air Baas Air mattresses of the state-of-the-art exhibit a "hard"
response when properly inElated. This is because the inner structural members or bafEles which are attached to the inner walls of the air bag are non-elastic. An attempt to "soften" the response of such a mattress through under inflation results in a dimensionally unstable unit with a "rumpled" and therefore unsatisfactory action surEace.
The variable response basic units of the present invention are now applied as internal structural members in place of the non-elastic ones. The lengths and cross-sections oE these rubber band couples are carefully designed to fit the mattress, and provide for the proper "softness" in use. As beEore, the ends oE
the coup~.es are attached to the inner walls of the air bag, as elastic connectors. The air mattress illustrated in Figure 7 shows only top and bottom surfaces connected by parallel couplings of rubber bands.
~:1 The elastic couple connectors function to maintain the shape of the mattress when it is inflated. The variable -response ,~,!

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ch~ cter of the couples oE my invention allows the selE-same mattress to be used Eor small children sleepers, or for the accommodation oE heavy adults. This is done as follows: The mattress and Variable Response units are so deslgned that when the mattress is properly inflated the desired mattress dimensions are achieved while at the same time the shortest (and wealcest;
see Figure 1, Curve C) rubber bands are just slightly tensed.
When a child lies on the mattress, the couples directly beneath him actually are relieved of tension while those everywhere else in the mattress are tensed more that they were in the rest state.
The initial couple response is "soft," so the child lies comfortably on the mattress. IE an adult were to lie on the mattress, initial response would be "soft," but firm, as with a child. But with the increased weight of the adult, the subsequent, firmer, reaction of the couples (Figure 1, Curve C) sets in, so that the adult does not sinlc too far into the mattress.
Thus the selfsame mattress is versatile, being satisfactory for both lightweight and heavy bodies.
If a given mattress is always to be used for children, it can be slightly underinflated without destroying the look and feel of the action surface. If it is to be used only for adults, inflation can be increased slightly. Obviously this process is reversible, the same mattress being used underinflated for one application, overinflated for a subseyuent one, etc..
As the sleeper "rolls over" on the mattress, the coupling relaxations and tensions already discussed are simply transferred from one part of the mattress to another. The result is equal ~ comfort to the sleeper at any location on the mattress. Whren the j~ sleeper rises out of bed, the mattress returns to its original "rest" configuration, all band couplings being tensed more or less equally. This is so because the air pressure within the inflated air mattress is the same at every point within the mattress.
~J Limit-Bands are, in general, recommended for ùse in parallel ;:~ with each parallel rubber band coupling. They will not be necessary only in the event that the strongest band, or bands, within the couple are so strong that they can handle the greatest pressure (the heaviest adult) lilcely to be applied wlthout distorting excessively the physical dimensions oE the mattress in use .
The Air Inflatable Bed Pillow A unique situation exits with the bedpillow. Ever since its ~1 earliest use people have desired a pillow that supports the head when they lie on their sides, but "collapses' when they lie on their backs with the head on the pillow. Various contraptions have been developed, and even marketed, to solve this problem, none successfully. For example, there is the half-donut configuration which ~lorks in theory ~ut not in practice.

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lo ~2 ~ 13 3 2 3 The inflatable air pillow oE my invention, for the Eirst time, addresses the problem through the unique workings of its internal rubber band baEEle system. Thus, the Normal Response of a rubber band (Figure 1, Curves A and B) is uniquely suited for use as the internal structural component of a pillow-shaped airbag. The pillow ~ives firmness when the sleeper is on his side, and "gives" when the sleeper is on his back, with head on the pillow. In this application the Limit-Band is actually j undesirable ie it is too ~short~ relative to the single band with which it is in parallel; the idea is to allow the band to stretch to a point at which its cross section diminishes ( and weakens the band), but yet not to a point (greater than 200%) where the band will deteriorate in use.
Whereas the use of a group of single rubber bands, connected to the two internal surEaces oE the inflatable pillow, will show the desired response characteristic, I have further discovered a means of enhancing this action. It is based upon the following observation: when a 2-inch long rubber band is stretched by 2 (more) inches, its response shows the characteristic increase in slope of the strain/stress curve (Figure 1, Curves A,B). When a 6-inch rubber band of the same cross section is stretched by 2 inches, the response curve is still linear. For the pillow application, however, it is desirable to experience the non-linear response. Hence the gap between two internal pillow surfaces should be bridged by short bands, the total desired bridge distance being supplemented by non-elastic bands in series with the short rubber bands. The short rubber bands can also employ parallel Limit Bands in order to increase the working life of the bands. Figure 8 shows this extremely simple bu novel employment of the rubber band baffle inside an inflatable air ?illow.
Note the important fact that use of elastic and non-elastic members in series is not equivalent to the use of a number of short rubber bands connected in series to bridge the internal pillow gap. The latter configuration is equivalent to using long rubber bands.
The non-elastic members can of course be replaced by very stoùt rubber bands which to all intents and purpose behave like non-elastic bands. In this event, the invention falls under the Examples already presented for the great variety oE band combinations employed. The specific, simplest embodiment of the bed pillow conEiguration would be, for example, -8B-2~-8B-, which represents a short, wealcer band sandwiched between two stout bands which act essentially as non-elastic members.
Thus the general claim for the invention can be understood "7 to cover such specific embodiments as illustrated here.
I have illustrated how coupling oE individual rubber bands can be useEully applied to exaggerate the Normal Response, as ., ,:
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apl` ed to the pillo~, as ~ell as to achieve the Variable Response as applied to the bedmattress or similar devices. Thus both response curves - concave upwards, and concave do~nwards in Fi~ure 1 - are usefully applied.
Mechanics of the Inflatable Air Baq Embodiment The rubber bands, or rubber strips, as the case may be, are joined to the inside surfaces of the air bag by means oE tabs that are built into the airbag. Currently, electronic welding of plastic tabs to the body of the plastic airbag will be the method ~ used. The tabs in turn hold the rings or hooks through which the 't rubber bands are secured. The rings may be of metal or plastic, !~ or may even be of nylon cord tied into a loop. It is conceivable that the inflatable pillow or mattress will contain no metal parts whatsoever, thereby contributing to a ligh-tweight finished article.
The means of attaching rubber bands or strips to bag interior surfaces is not limited to the method described.
' A valve located at the pillow edge, or mattress edge will be required to fill the bag with air, or to deflate the bag when ~ necessary. To inflate the pillow, no airpump is required, as the r~ user can inflate it with his own breath. To inflate a mattress will require use of a mechanical-action pump such as the foot- or pedal-pump. Alternatively, an electric airpump is used. Vacuum cleaners used in the home often have provisions for pumping air.
At any rate, an inexpensive airpump can be supplied with each mattress.
For institutional use, where several score or several hundred mattresses are used on the same premises, only a small number of airpumps will be required, certainly not one for every mattress.
For camping purposes, airmattresses, being generally smaller than home bed mattresses, can be inflated using a mechanical airpump.
The bed mattress and pillow of the present invention are autoclavable, either in an inflated state, or as collapsed.
In order to take the yuess work out of achieving proper inflation, an inexpensive pressure indicator i5 incorporated into the airvalve, which visually functions as a go/no-go device. The indicator may be overridden by the user. Such an indicator ~ device is not a requisite part of the present invention, but a '!~ feature oE the preferred commercial embodiment.
Ease of manufacture is an important feature of any ~ mechanical invention. Referring to the embodiment oE an ",j .
i~3 airmattress in Figure 7, the rubber-bands are all fastened, at one end, to one airbag surface, either the upper or the lower one. At this point such a sur~ace is just a plastic sheet, and not yet a bag. The opposing sheet is then placed in position relative to the sheet to which bands are af~lxed. Then the ~$~
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opposite, or "loose" end of each band is fastened to the opposite sheet, starting from one end of the sheet, and working towards the other. Thus, fastening both ends of each band does not pose an impossible problem in construction. When all bands are secured to the inside surfaces of the sheets, the airbag "sides and ends" are attached to the sheets through electronic welding. The airpillow is similarly constructed.
Although this invention has been described in connection with specific forms thereof, it will be appreciated by those skilled in the art that a wide variety of equivalents may be substituted for these specific elements and steps of operation shown and described herein, that certain features may be used independently of other features, and that parts may be reversed, all without departing from the spirit and scope of this invention as defined in the appended claims. For example, the invention encompasses the coupling o~ tension-response devices other than rubber bands or strips, such as steel springs.
Also, in the inflatable air mattress application, for example, all internal structural units need not be identical, as they are shown to be in Fig.
7. "Soft" response units may be alternated with "hard"
response units all across the working surface of the mattress. The "soft" response units may be comprised simply of single, weaker rubber bands. Coupled in parallel with these single rubber bands could be Limit Bands which prevent the rubber bands from ~tretching past a pre-designated limit, e.g., 150-200% beyond their rest leng~hs. The "hard" response units may be ~!
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comprised simply of single, stronger rubber bands. The ~-latter may or may not be coupled in parallel with Limit Bands. ~ :
The overall response of a mattress using alternating "soft" and "hard" units is as covered in Claim 13.
Note a definite parallel between the "alternating" design above, and the Series Variable Response System, p.5. Thus, upon the application of stress (putting weight on the mattress), all rubber bands begin to stretch simultaneously, with the weaker bands obviously stretching more than the stronger onesO
(Of course, the rubber bands directly beneath the body on the mattress, are not stretched but "collapsed", as discussed earlier). ~
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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1.) The coupling of two or more tension-response devices in such a way that the combined tension response a.) is non-linear over the allowed range of applied tension, and b.) becomes progressively diminished as the applied tension increases, over the allowed range of applied tension.

2.) The coupling of Claim 1 wherein the tension response devices are rubber bands or strips.

3.) The coupling of Claim 1 wherein a.) the tension-response devices are individual rubber bands, b.) the coupling is of the parallel type, c.) at least two of the bands in the coupling differ is length, and d.) the rest length of the longest band is less than twice that of the shortest band.

4.) The coupling of Claim 3 wherein the maximum in the allowed range of tension is such that the shortest band in the coupling never stretches beyond twice it's rest length.

5.) The coupling of Claim 3 wherein a relatively inelastic limit band is added to the parallel-coupled rubber bands, the length of the limit band being no greater than twice the rest length of the shortest rubber band in the couple.

6.) The coupling of Claim 1 wherein a.) he tension-response devices are individual rubber bands, b.) the coupling is of the series type, and c.) at least two of the bands in the coupling differ in strength.

7.) The coupling of Claim 6 wherein the maximum in the allowed ?ange of tension is such that the weakest band in the coupling never stretches beyond twice its rest length.

8.) The coupling of Claim 6 wherein individual rubber bands in the series are parallel-coupled with limit bands constructed of relatively non-elastic material, the length of each limit band not to exceed twice the rest length of the rubber band to which it is coupled.

9.) The coupling of Claim 1 wherein a.) the tension-response devices are parallel-coupled rubber band units, b.) the coupling is of the series type, and c.) at least two of the parallel-coupled rubber band units differ in strength.

10.) The coupling of Claim 9 wherein the maximum allowed range of tension is such that the shortest individual rubber band in the weakest parallel-coupled unit never stretches beyond twice its length.

11.) The coupling of Claim 9 wherein individual parallel- coupled units are further parallel-coupled with limit bands constructed of relatively inelastic material, the length of each limit band not to exceed twice the rest length of the shortest rubber band in the parallel-coupled rubber band unit to which it is coupled.

12.) An inflatable air mattress wherein the internal structural support system is comprised of rubber band tension-response units.

13.) The mattress of Claim 12 wherein the pressure response of the mattress a.) is non-Linear over the practical use range of applied pressure, and b.) becomes progressively diminished as the applied pressure increases, over the practical use range of applied pressure.

14.) The mattress of Claim 13 wherein a.) the tension-response units are comprised of two or more rubber bands coupled in parallel, b.) at least two of the parallel-coupled rubber bands differ in length, and c.) the rest length of the longest band in the couple is less than twice that of the shortest band.

15.) The mattress of Claim 14 wherein a relatively inelastic limit band is included in each parallel-coupled rubber band unit, the length of the limit band being no greater than twice the rest length of the shortest rubber band in the unit to which it is coupled.

16.) An inflatable air bed pillow wherein the internal structural support system is comprised of rubber band tension-response units.

17.) The bed pillow of Claim 16 wherein a.) the rubber band tension-response units consist of two or more series-coupled rubber bands, and b.) at least two of the bands in the series differ in strength.

18.) The bed pillow of Claim 17 wherein a limit band of relatively inelastic material is coupled in parallel with the weakest rubber band in the series, the length of the limit band not to exceed twice the rest length of the rubber band to which it is coupled.