Abstract:
A sleep surface is formed by joining longitudinal sides of two juxtaposed air bladders, thereby providing a continuous sleep surface having two independently inflatable air chambers. The union of the two bladders ensures that the bladders remain in a desired position despite being repeated inflated, deflated, folded and unfolded. A support member can be inserted and secured between the two independently inflatable air bladders to provide an enhanced continuous sleep surface.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of U.S. application Ser. No. 10/801,769 filed Mar. 16, 2004, the entirety of which is hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     Airbeds are rapidly gaining popularity as an alternative to inner spring mattresses. One of the most attractive features of an airbed is the inherent firmness adjustability. As opposed to a non-adjustable inner spring mattress, the firmness of an air bed can be quickly adjusted simply by changing the air pressure in the bladders of the bed. The larger beds include two juxtaposed bladders, thereby providing two independently adjustable sleep surfaces in a single bed.  
         [0003]     As depicted in  FIG. 1 , beds offering two bladders were originally constructed simply by providing a cover  2 , inserting a foam border  4  around the inner sidewalls of the cover  2  to provide a desirable shape for the mattress  10 , and inserting two independent juxtaposed bladders  12 ,  14  inside the foam border  4 . Based on this construction, some customers expressed concern that when they were on inside edge  8  of their bladder  12  or  14 , toward the center of the bed, their body weight forced all of the air in the bladder  12  or  14  toward the outer side  6  of the bladder  12  or  14 , leaving them in a low point on the mattress. If their sleeping partner was lying on the center of the other bladder  12  or  14 , the inside edge  8  of the spouse&#39;s bladder  12  or  14  would be fully inflated. The discontinuity between the inside edge  8  of the compressed bladder  12  or  14  and the fully inflated adjoining inside edge  8  of the adjacent bladder  12  or  14 , created an uncomfortable sleeping surface. Though this problem was somewhat alleviated by the incorporation of foam covers and pillow top mattress covers, the effect was still noticeable.  
         [0004]     Recently, another advantage of airbeds has resulted in the development of sleeper sofas with airbed mattresses. The advantage is that the airbeds can be deflated, virtually eliminating the space used by the mattress. Conventional sleeper sofa designs are plagued with a struggle between providing a comfortable sleep surface when the bed is deployed, and providing an attractive sofa when the bed is hidden away. A thick, comfortable mattress is difficult to fold into a couch. Mattresses that are foldable are too thin to insulate a sleeper from the non-uniform support surface under the mattress.  
         [0005]     Airbed mattresses eliminate this problem because they can be deflated before the bed is folded into the couch. Thus, the thickness of the mattress is completely independent of the mechanical structure of the sofa mechanisms. The development of airbed sleeper sofas has quickly progressed to the inclusion of a mattress having two bladders.  
         [0006]     A sleeper sofa airbed mattress with two bladders brings with it the same potential problem of a gap between the bladders when inflated. The deflation of the bladders during storage creates a new potential problem as well. Namely, the deflated bladders may become overlapped or otherwise wrongly positioned during the folding and unfolding of the sleeper sofa. Simply placing a piece of foam between the bladders is not effective because when left unsecured, unattached or otherwise not held in place between the bladders, the foam is likely to become displaced when the bladders are inflated, deflated, folded and/or unfolded.  
         [0007]     Thus, there is a need for an airbed mattress having two independent bladders that remain in position while being inflated, deflated, folded and/or unfolded. There is a further need for this mattress to provide a sufficient level of firmness across the extents of the mattress so an individual sleeper does not feel drawn to a depression in the middle of the bed. There is yet another need for securing a support member between two independent air bladders such that the support member remains in position while the two independent bladders are inflated, deflated, folded and/or unfolded.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     The present invention relates to an airbed mattress that provides a solution to the aforementioned problems. More specifically, the present invention relates to an airbed mattress that includes two juxtaposed bladders that are joined along adjoining longitudinal edges. The union formed not only keeps the bladders in place during deflation and folding, but a bridge is formed between the mattresses creating a relatively constant sleep surface across the extents of the mattress. An additional support member prevents an individual sleeper from rolling to the center of the mattress.  
         [0009]     Thus, one aspect of the present invention provides a sleep surface for two people comprising a first bladder having a longitudinal side and a second bladder having a longitudinal side attached to the longitudinal side of the first bladder. Each bladder is constructed and arranged to maintain an air pressure therein that is independent of an air pressure in the other bladder. The feature of two independently adjustable sleep surfaces is thus maintained. Additionally, a support member can be inserted between the bladders to enhance the continuous sleep surface of the air mattress.  
         [0010]     The longitudinal sides of the two bladders may be heat welded, zipped, connected with hook and loop fasteners, snap fasteners, tied, or any acceptable fastening means. Additionally, the sides of the two bladders may be connected at an upper edge or both an upper and lower edge.  
         [0011]     Another aspect of the present invention provides a method of creating an uninterrupted sleep surface with two bladders. The method includes providing a first elongate bladder and a second elongate bladder. The bladders are then juxtaposed, a support member is inserted between them, and they are joined together. Joining the bladders is accomplished through heat welding, zipping, connecting with hook and loop fasteners, connecting with snap fasteners, tying the bladders together, or any acceptable fastening means.  
         [0012]     Yet another aspect of the present invention provides a mattress with a sufficiently thin profile, when deflated, to be capable of being folded into a sleeper sofa; and when inflated provides sufficient insulation between the sleeper and the non-uniform support surface under the mattress to ensure a restful night&#39;s sleep. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a perspective view of a known air mattress having two independent air bladders.  
         [0014]      FIG. 2  is a perspective view of sections of two bladders to be joined to form an air mattress in accordance with the present invention.  
         [0015]      FIG. 3  is a diagrammatic representation of the air mattress of the present invention.  
         [0016]      FIG. 4  is a perspective view of a joined portion of one embodiment of the air mattress of the present invention.  
         [0017]      FIG. 5  is a perspective view of a joined portion of an alternative embodiment of the air mattress of the present invention.  
         [0018]      FIG. 6  is a cross-sectional view of a joined portion of another alternative embodiment of the air mattress of the present invention.  
         [0019]      FIG. 7A  is a graph illustrating a displacement profile for a first test mattress at a first pressure configuration.  
         [0020]      FIG. 7B  is a graph illustrating a displacement profile for a second test mattress at the first pressure configuration.  
         [0021]      FIG. 8A  is a graph illustrating a displacement profile for the first test mattress at a second pressure configuration.  
         [0022]      FIG. 8B  is a graph illustrating a displacement profile for the second test mattress at the second pressure configuration.  
         [0023]      FIG. 9A  is a graph illustrating a displacement profile for the first test mattress at a third pressure configuration.  
         [0024]      FIG. 9B  is a graph illustrating a displacement profile for the second test mattress at the third pressure configuration. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]     Referring now to  FIG. 2 , there is shown a pair of air bladders  12  and  14  that are to be joined to form an air mattress  10  of the present invention. Air mattress  10  is designed to accommodate one person on each bladder  12  and  14 . Both of air bladders  12  and  14  have upper surfaces  16 , lower surfaces  18  and longitudinal sides. Longitudinal side  20  of first air bladder  12  includes first upper lip  22 , first lower lip  24 , and first side portion  23  collectively forming a first joining element  29 . Similarly, longitudinal side  21  of second bladder  14  includes second upper lip  26 , second lower lip  28 , and second side portion  27  collectively forming second joining element  31 .  
         [0026]     Referring to  FIG. 3 , bladders  12  and  14  are fluidly attached to pump  33 . To the extent that there is more than one bladder, it may be desired to provide a separate pump for each bladder  12  and  14  or to provide one pump operably connected to all of the bladders  12  and  14 . Pump  33  is in electrical communication with manual remote controls  35  via control box  37 . Control box  37  operates pump  33  to increase or decrease the fluid pressure of bladders  12  and  14 .  
         [0027]     Referring now to  FIG. 4 , air mattress  10  in accordance with the present invention has been formed by joining longitudinal side  20  of first air bladder  12  to longitudinal side  21  of second bladder  14  to form receiving channel  45  bounded by first and second upper lips  22 ,  26 , first and second lower lips  24 ,  28  and first and second side portions  23 ,  27   
         [0028]     In one embodiment of the present invention, upper surface  16  of first air bladder  12  may be made continuous with upper surface  16  of second air bladder  14  by permanently attaching upper lip  22  of first longitudinal side  20  to upper lip  26  of second longitudinal side  21 . In this manner a permanent union  30  is created between first longitudinal side  20  of first air bladder  12  and second longitudinal side  21  of second air bladder  14 . One skilled in the art will realize that the term “continuous”, as used herein, is referring to the somewhat planar and horizontal upper surface of the resulting air mattress  10 . This may be accomplished by joining a portion or all of upper lip  22  of first longitudinal side  20  to upper lip  26  of second longitudinal side  21 . Additionally, this union  30  may be intermittent.  
         [0029]     The strength and integrity of union  30  may be increased by making lower surface  18  of first air bladder  12  continuous with lower surface  18  of second air bladder  14 . This continuity may be achieved by permanently attaching lower lip  24  of first longitudinal side  20  to lower lip  28  of second longitudinal side  21 . Permanent union  30  may be achieved through any acceptable joining mechanisms or techniques including, but not limited to, heat welding, zipping, adhering, bonding, or sewing.  
         [0030]     More specifically, union  30  of the embodiment shown in  FIG. 4  has been formed by overlapping upper lips  22  and  26 , overlapping lower lips  24  and  28 , and joining the contacting surfaces together. The resulting union  30  is further strengthened, in a preferred embodiment, by adding reinforcement members  32  over the joined lips on upper and lower surfaces  16  and  18 , and joining these members to both bladders  12  and  14 .  
         [0031]     Reputable airbed manufacturers warrant the bladders sold against leaks. In the event of a leak in one of bladders  12  or  14 , the manufacturer will send a replacement bladder in exchange for the faulty bladder. If the airbed includes an air mattress  10  that includes two bladders  12  and  14  that are permanently joined, the exchange will necessarily include the shipment of a non-defective bladder along with the defective bladder. In order to minimize the additional shipping charges as well as the costs associated with accepting a perfectly functional bladder as defective, an alternative embodiment of an air mattress of the present invention is shown in  FIG. 5  that includes a separable union  32  that may be disassembled in the event that it is desired to separate bladders  12  and  14 , such as for purposes of exchanging a defective bladder.  
         [0032]     Separable union  32  of air mattress  10 ′ is effected by joining mechanism  34 . Joining mechanism  34  is shown as a zipper but one skilled in the art will quickly realize that other joining mechanisms may be utilized without departing from the scope of the invention; for example, hook and loop fasteners, adhesives, snaps, laces, buttons, magnets, Velcro and/or the like may be used. Also, union  32  may be continuous, intermittent, or partial. In one embodiment, a first portion  36  of joining mechanism  34  is attached to upper lip  22  of first bladder  12 . A second portion  38  of joining mechanism  34  is attached to upper lip  26  of second bladder  14 . First portion  36  and second portion  38  are configured to mate with each other in order to form separable union  32 . The various portions of joining mechanism  34  may be coupled to bladders  12  and  14  during the bladder manufacturing process, or may alternatively be coupled to the bladders at some later time.  
         [0033]     Alternately, separable union  32  further includes a second joining mechanism  40 , which may or may not be similar to joining mechanism  34 . Joining mechanism  40  includes a first portion  42  attached to lower lip  24  of first bladder  12  and a second portion  44  attached to lower lip  28  of second bladder  14 . First and second portions  42  and  44  are configured to mate with each other to join lower lips  24  and  28  together.  
         [0034]     Heretofore, unions  30  and  32 , either permanent or separable, have been described as being formed along either the top edges of adjacent bladders  12  and  14 , or the top and bottom edges of bladders  12  and  14 . Some of the objects of the present invention may be accomplished by adjoining bladders  12  and  14  along a mid portion of their adjacent side walls. However, doing so not only lowers the effective “bridge” that is formed between bladders  12  and  14 , it necessarily increases the separation force felt by union  30  or  32  when a person is laying on or near union  30  or  32 . Therefore, while such a union is contemplated and considered within the scope of this disclosure, the union would have to be of heavier construction to withstand the additional force or contain a support member  46  as described below. Thus, there are advantages to union  30  or  32 , either permanent or separable, when the top edges are joined.  
         [0035]     Referring now to  FIG. 6 , there is depicted another alternative embodiment of an air mattress in accordance with the present invention. Air mattress  10 ″ includes permanent union  30  or separable union  32  created by joining mechanism  34  and second joining mechanism  40  as previously discussed. In order to greatly reduce the effects of the “roll to the middle” phenomenon experienced when a person is lying on or near union  30  or  32 , a support member  46  is inserted in receiving channel  45  between bladders  12  and  14 . In particular, the roll to the middle phenomenon generally refers to the vertical movement that a person feels as he/she is lying on an air bladder and rolls or moves toward the junction between the two bladders near the middle of the air mattress. The vertical movement results in an undesirable sensation that the person is sinking into a low spot in the mattress. In addition, it may be difficult for some individuals to roll from the low point near the middle of the mattress back to his/her side of the air mattress. Thus, providing support member  46  between bladders  12  and  14  creates a flatter, more uniform surface and greatly reduces or eliminates the effects of the roll to the middle phenomenon. Those skilled in the art will appreciate that support member  46  may be constructed of another inflatable member, any type of foam, solid structures or any other materials that provide sufficient support to a person laying on or near union  30  or  32 . In one embodiment, support member  46  is constructed of foam. Numerous types of foam may be used such as, for example, polyurethane polyether foam.  
         [0036]     Support member  46  is sized to accommodate receiving channel  45  as defined by first and second side portions  23 ,  27 , first and second upper lips  22  and  26 , and first and second lower lips  24  and  28 . Bladders  12  and  14  can also be positioned between two side rails  48  and  50  attached to a bed frame (not shown) to provide additional support to air mattress  10 ″.  
         [0037]     Whether the configuration of the air mattress in accordance with the present invention is that as depicted in  FIGS. 4, 5  or  6 , when deflated, it can fold into a sleeper sofa with ease. Thus, when inflated an air bed mattress can be as thick as a non-air bed mattress to provide sufficient support to a sleeper from the mechanical structure of the bed frame, and when deflated can be thin enough to be independent of the mechanical structure of the sleeper sofa mechanism.  
         [0038]     In operation, a sleep surface having a continuous upper surface  16  is created by juxtaposing first bladder  12  and second bladder  14 . Once juxtaposed, union  30  or  32  is formed by attaching upper lip  22  of first bladder  12  to upper lip  26  of second bladder  14 . Union  30  or  32  may be made stronger by attaching lower lip  24  of first bladder  12  to lower lip  28  of second bladder  14 . Alternately, union  30  or  32  may be further supported by inserting support member  46  in receiving channel  45  between bladders  12  and  14 .  
         [0039]     In order to verify the improvements in the roll to the middle phenomenon exhibited by air mattress  10 ″ having foam support  46  and bladders  12  and  14  that are zippered together, a roll to the middle test was performed on air mattress  10 ″ with a Rollator machine of the type commonly used for testing mattresses in accordance with ASTM standards. However, the Rollator machine was modified such that it was capable of measuring the vertical displacement that would be felt by a person near the junction of bladders  12  and  14 . For purposes of comparison, a second dual chamber test air mattress was tested that also included a foam support member  46  disposed between the two bladders. However, the air bladders in the second test mattress did not include upper or lower lips structured to couple the bladders together and create a receiving channel for support member  46 .  
         [0040]     In order to test air mattress  10 ″ (which will hereinafter be referred to as the “first test mattress”), the mattress was placed on the surface plate of the Rollator machine. The Rollator machine generally included a large cylindrical roller coupled to a traveling arm configured to move the cylindrical roller horizontally across the air mattress. The cylindrical roller had a diameter of about 17 inches, a length of about 36 inches, and weighed about 240 pounds. The traveling arm included two strain gauges configured to measure vertical displacement of the cylindrical roller as it traveled in a horizontal direction across the air mattress. In particular, a strain gauge was positioned on the traveling arm near each end of the cylindrical roller to verify that, as the roller was displaced in a vertical direction, the roller did not tilt or experience any uneven vertical movement. An additional strain gauge coupled to the motor output rod driving the traveling arm in a horizontal direction was configured to provide an accurate measurement of the horizontal position of the cylindrical roller as it traveled across the air mattress. The cylindrical roller was set to a cycle speed of approximately 3.5 cycles per minute, wherein a single cycle was defined by the horizontal movement of the cylindrical roller from the mid-point of one bladder to the mid-point of the other bladder, and then back again. The speed of the cylindrical roller was selected so as to approximate the speed at which a person may roll over while asleep on the air mattress. Data acquisition software coupled to the strain gauges documented vertical displacement of the cylindrical roller as the roller was driven in a horizontal direction back and forth across the air mattress for a number of cycles that ranged from 4 to 7. The data collected by the data acquisition software was then compiled as will be summarized below.  
         [0041]     The profile test procedure was performed on the first test mattress at various chamber pressures. In particular, both of the bladders were initially set to a Sleep Number® setting of 100, which corresponds with a bladder pressure of about 0.65 psig. Next, both of the chambers were set to a Sleep Number® setting of 45, which corresponds with a bladder pressure of about 0.32 psig. Finally, one of the bladders was set to a Sleep Number® setting of 70, which corresponds with a bladder pressure of about 0.42 psig, while the other bladder was set to a Sleep Number® setting of 30, which corresponds with a bladder pressure of about 0.26 psig. These three configurations were selected to provide displacement data for a wide range of bladder pressure values.  
         [0042]     After completing the entire profile test procedure with the first test mattress at the various bladder pressures described above, the same profile test procedure was performed on the second test mattress.  
         [0043]     Next, for each of the three pressure configurations, the average vertical displacement exhibited by the first and second test mattresses was determined by averaging a plurality of data points (dependent upon the number of test cycles) corresponding to the maximum vertical displacement at the junction of the two bladders. These results will be discussed in more detail below in reference to Tables I-III. In addition, the data acquired with the data acquisition software was compiled and displacement profiles were created, as illustrated in  FIGS. 7A-9B . In each of the displacement profiles, the x-axis represents the horizontal distance traveled by the cylindrical roller across the mattress, while the y-axis represents the vertical displacement detected by the cylindrical roller at each horizontal mattress position. As shown in the displacement profile figures, the x-axis has a range from 0 inches to 24 inches. The “0” mark represents the mid-point of the first bladder, the “24” mark represents the mid-point of the second bladder, and the “12” mark represents the junction between the first and second bladders where support member  46  was located. Along the y-axis, the data acquisition software was calibrated such that at the starting point of each cycle (i.e., the “0” mark on the x-axis), the vertical displacement was set at 0.00 inches. Thus, the “0.00” mark along the y-axis represents the baseline from which all vertical displacements along the air mattress were measured.  
         [0044]     Table I below summarizes the test results for the first and second test mattresses at the first test configuration, wherein both bladders were set to a Sleep Number® setting of 100. In addition,  FIG. 7A  illustrates the displacement profile for the first test mattress, while  FIG. 7B  illustrates the displacement profile for the second test mattress. As shown in Table I and  FIGS. 7A-7B , the maximum vertical displacement at the junction of the two bladders in the first test mattress was 0.41 inches with a standard deviation of 0.03 inches over 5 test cycles, while the maximum vertical displacement at the junction of the two bladders in the second test mattress was 1.15 inches with a standard deviation of 0.02 inches over 4 test cycles. Thus, as evidenced by the test results in Table I, the first test mattress, which included a foam support disposed within a receiving channel formed by adjacent upper and lower lips of the two bladders zippered together, exhibited a reduction in vertical displacement of 0.74 inches over the second test mattress having a foam support disposed between two bladders that are not zippered together.  
                           TABLE I                               Standard               Average Max   Deviation   Number of       Test Air Mattress   Displacement (in.)   (in.)   Test Cycles                   First Test Mattress   0.41   0.03   5       Second Test Mattress   1.15   0.02   4                  
 
         [0045]     Table II below summarizes the test results for the first and second test mattresses at the second test configuration, wherein both bladders were set to a Sleep Number® setting of 45. In addition,  FIG. 8A  illustrates the displacement profile for the first test mattress, while  FIG. 8B  illustrates the displacement profile for the second test mattress. As shown in Table II and  FIGS. 8A-8B , the maximum vertical displacement at the junction of the two bladders in the first test mattress was 0.44 inches with a standard deviation of 0.00 inches over 6 test cycles, while the maximum vertical displacement at the junction of the two bladders in the second test mattress was 1.23 inches with a standard deviation of 0.04 inches over 7 test cycles. Thus, as evidenced by the test results in Table II, the first test mattress exhibited a reduction in vertical displacement of 0.79 inches over the second test mattress at the second pressure configuration.  
                           TABLE II                               Standard               Average Max   Deviation   Number of       Test Air Mattress   Displacement (in.)   (in.)   Test Cycles                   First Test Mattress   0.44   0.00   6       Second Test Mattress   1.23   0.04   7                  
 
         [0046]     Finally, Table III below summarizes the test results for the first and second test mattresses at the third test configuration, wherein one of the bladders was set to a Sleep Number® setting of 70, while the other bladder was set to a Sleep Number® setting of 30. In addition,  FIG. 9A  illustrates the displacement profile for the first test mattress, while  FIG. 9B  illustrates the displacement profile for the second test mattress. As shown in Table III and  FIGS. 9A-9B , the maximum vertical displacement at the junction of the two bladders in the first test mattress was 0.91 inches with a standard deviation of 0.04 inches over 5 test cycles, while the maximum vertical displacement at the junction of the two bladders in the second test mattress was 1.51 inches with a standard deviation of 0.05 inches over 7 test cycles. Thus, as evidenced by the test results in Table III, the first test mattress exhibited a reduction in vertical displacement of 0.60 inches over the second test mattress at the third pressure configuration.  
                           TABLE III                               Standard               Average Max   Deviation   Number of       Test Air Mattress   Displacement (in.)   (in.)   Test Cycles                   First Test Mattress   0.91   0.04   5       Second Test Mattress   1.51   0.05   7                  
 
         [0047]     As one skilled in the art will appreciate based upon the test results summarized above, a dual chamber air mattress that includes a support member disposed within a receiving channel formed between two adjacent bladders that are coupled together greatly reduces the effects of the roll to the middle phenomenon. Although the roll to the middle test was performed on an air mattress having a foam support member disposed between two bladders that were zippered together, one skilled in the art will further appreciate that support members formed from other types of materials and coupling means other than zippers may also be used to minimize the roll to the middle phenomenon in accordance with the present invention.  
         [0048]     Those skilled in the art will further appreciate that the present invention may be embodied in other specific forms without departing from the spirit or central attributes thereof. In that the foregoing description of the present invention discloses only exemplary embodiments thereof, it is to be understood that other variations are contemplated as being within the scope of the present invention.  
         [0049]     Accordingly, the present invention is not limited in the particular embodiments which have been described in detail therein. Rather, reference should be made to the appended claims as indicative of the scope and content of the present invention.