Patent Publication Number: US-6704960-B1

Title: Support device

Description:
When irregularly shaped objects are supported on a resilient surface, the surface becomes irregularly loaded, resulting in excessive supportive pressure on parts typically prominent parts of the object, and insufficient support on other parts typically less prominent parts of the object. 
     According to one aspect of the invention there is provided a support device which includes a plurality of resiliently deformable support units each of which has a pre-compression induced in a load direction, the support units being arranged such that further compression of one support unit in the load direction will cause a reduction in compression of an adjacent support unit. 
     The support units may be interconnected and the pre-compression is induced by laterally pre-tensioning the support units. 
     According to another aspect of the invention there is provided a support device which includes a plurality of resiliently deformable support units each of which is laterally connected to at least one other support unit and being configured such that when subjected to a compressive load in a load direction, it deforms laterally in a manner which induces an extensile loading of the at least one other support unit to which it is connected. 
     The term “connected” is to be understood to include an arrangement where load transmission between the support units occurs and includes for example where adjacent support units butt against each other, have a positive mechanical connection, or the like. 
     Each of the support units may be pre-tensioned laterally such that increased compression of one support unit in the load direction will cause a reduction in compression of the at least one other support unit to which it is connected. 
     The support units may be pre-tensioned by laterally pre-tensioning the support device, e.g. in a peripheral frame. Instead, or in addition, the support units may be pre-tensioned interdependently against each other and/or against internal spacers. 
     Each support unit may include a pair of ends spaced apart in the load direction and at least one elongate support element extending between the ends and configured to buckle laterally in a predetermined direction when the support unit is subjected to a compressive load in the load direction. 
     Interconnected support units may be connected together via their support elements, interconnected support elements being configured to buckle in opposite directions usually towards each other. 
     In one embodiment of the invention the interconnected support elements of interconnected support units may be connected together via connecting members extending laterally between the support elements. The connecting members may be articulated to the support elements. The connecting members may be in the form of struts, preferably, however, the connecting members are flexible and inelastic. 
     In another embodiment of the invention the interconnected support elements of interconnected support units may be connected directly to one another, e.g. by laterally bearing against each other. 
     The support device may be a unitary moulding of an elastomeric material. 
     Each support unit may include a plurality of support elements forming a resilient articulated frame. Each frame may define an octahedron, the support unit including four support elements, each of which has two angularly spaced limbs or parts defining two edges of the octahedron and being configured to deform laterally outwardly when the support unit is subjected to a compressive load in the load direction, the support elements being biased against outward buckling by resilient tensile elements spanning the octahedron internally. The two parts of each support element may be articulated. Preferably the included angle defined between the parts or limbs of a support element is obtuse. 
     The support device may include a plurality of the support units arranged in an interconnected matrix. 
     The support device may include at least two layers of support units superimposed one upon the other in the load direction. 
     The support device may be in the form of a mattress. 
    
    
     The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings. 
     In the drawings; 
     FIG. 1 shows a three-dimensional view of part of a first embodiment of a support device in accordance with the invention; 
     FIG. 2 shows a three-dimensional view of part of a second embodiment of a support device in accordance with the invention; 
     FIG. 3 shows a support unit of the support device of FIG. 2; 
     FIG. 4 shows a side view of part of a third embodiment of a support device in accordance with the invention; 
     FIG. 5 shows a top plan schematic view of part of the support device of FIG. 4; 
     FIG. 6 shows a sectional side view of part of a fourth embodiment of a support device in accordance with the invention; and 
     FIG. 7 shows part of a fifth embodiment of a support device in accordance with the invention. 
    
    
     Referring to FIG. 1 of the drawings, reference numeral  10  refers generally to part of a first embodiment of a support device in accordance with the invention. 
     The support device  10  comprises a plurality of support units  12 , arranged in a matrix (part of which shown in FIG. 1 of the drawings). Each support unit  12  includes four support elements  16  spanning between an upper end  18  and a lower end  20 . Each support element  16  includes two angularly spaced parts or limbs, namely an upper part  16 . 1  and a lower part  16 . 2  which are articulated to buckle at a corner or outer joint  30 . The support elements  16  are arranged such that their parts  16 . 1 ,  16 . 2  lie along the edges of an octahedron. The ends of the parts  16 . 1 ,  16 . 2  of the support elements  16  are all articulated to permit their relative displacement as described in more detail herebelow. 
     Resilient tensile members in the form of coil springs  24  span the support unit  12  between opposing corners or outer joints  30 , to bias the support elements  16  against outward buckling. 
     Adjacent support units are interconnected by connecting members  14  and by connecting members  31  extending between the upper ends  18  and lower ends  20 . The connecting members  14  and connecting members  31  are articulated to the support units  12 . The connecting members  14  are typically flexible and inelastic. 
     The outer joints  30  of the matrix are connected to a supporting frame (not shown) through resilient members in the form of springs  25 . The tension in the springs  25  is selected so as expand the matrix in a lateral plane perpendicular to the load direction which serves to urge the joints  30  outwardly and thereby tension the springs  24 . This in turn causes a lateral pretension in each of the support units  12  which tends to reduce the height of the support units  12  in the load direction, i.e. the spacing between the upper end  18  and lower end  20  decreases. 
     A suitable support surface, e.g. the cover of a mattress, will be positioned over the support device. If an uneven or irregularly shaped load is placed on the support surface the load is carried on the support units  12  in a manner in which those support units  12  which are more heavily loaded tend to be compressed in the direction of arrow  54 . This compression of a support unit causes the joints  30  to be urged outwardly against the bias of the springs  24 . This outward displacement reduces the tension in the connecting members  14  connecting the adjacent joints  30  thereby tending to reduce the lateral pre-tension in the adjacent less heavily loaded support unit  12  and permit the support unit  12  to extend in the load direction under the inward bias of the springs  24  or at least to exert an upwardly directed, i.e. in a direction opposite to the direction of arrow  54 , load on any externally imposed surface loads. 
     As a result, heavily loaded areas of the support device  10  tend to be compressed and lesser loaded areas tend to extend providing added support over the lesser loaded areas. 
     The Inventor believes that the support device  10  will find application particularly, but not necessarily exclusively, in a mattress to support a prone person. In use, the mattress will have heavily loaded areas carrying the shoulders and hips of the person lying on the mattress compressed which will allow the structures in lesser loaded areas to extend. This extension provides for areas of the body such as the lower back and the neck to receive added support. 
     In this way, the Inventor believes that a mechanical arrangement which approximates the support offered by a waterbed is provided. This accordingly provides the advantages of support that a waterbed provides over a conventional sprung mattress without the disadvantages of high weight, regular maintenance and the like. 
     Reference is now made to FIGS. 2 and 3 of the drawings, in which reference numeral  100  refers generally to part of a second embodiment of a support device in accordance with the invention and, unless otherwise indicated, the same reference numerals used above are used to designate similar parts. 
     In this embodiment of the invention, each support unit  12  includes opposing tapering coil springs  26 , each tapering in the load direction  54  into a support element  16  which is straight prior to assembly of the support unit. Hence, a support unit  12  comprises two opposing one-piece composite elements  16 , 26  connected together at the extremities of the support elements  16 . When the support unit  12  is laterally tensioned at the midpoints  30  of the support elements  16 , the support elements  16  deform outwardly to form a parallelogram formation  28 . Each support element  16  is in the form of a relatively stiff coil spring which, as mentioned above, is formed integrally with the spring  26 . Further bowing and buckling occurs in the direction of pre-tensioning when the support element is subjected to a compressive load in the load direction. Flexible inelastic members  14  interconnect midpoints  30  of support units  12 , the support units  12  being arranged in a laterally extending matrix and alternating support units being connected in a first lateral direction and intermediate support units  12  being connected in a second lateral direction at an angle, typically perpendicular, relative to the first lateral direction. 
     The support device  100  is used in similar fashion to the support device  10  and, if desired, can be pre-tensioned, e.g. in a peripheral support frame in the manner described above with reference to FIG.  1 . 
     Reference is now made to FIGS. 4 and 5 of the drawings, in which reference numeral  200  refers generally to part of a third embodiment of a support device in accordance with the invention and, unless otherwise indicated, the same reference numerals used above are used to designate similar parts. 
     In this embodiment of the invention, each support unit  12  includes opposing tapering coil springs  26 , each seated on a seat member  32 . The upper and lower seat members  32  of each support unit are convergently biased in the load direction by a coil spring  34  under tension. Circumferentially spaced resiliently deformable support elements  36  span between the seat members  32 , each support element  36  being bent such that it bows outwardly. The bowed support elements  36  exert an effort on the seat members  32  in a direction opposite to that of the coil spring  34  to maintain the tension in the coil spring  34 . Compression of the support units  12  in the load direction  54  results in further outward bowing of each of the support elements  36 . The coil springs  34  hold the seat members  32  of each support unit  12  together by retaining each support element  36  in a bent pre-compressed condition between seat formations  38  defined in each seat member  32 . Adjacent support units  12  are interconnected by connecting members  14  spanning between adjacent support elements  36  of adjacent support units  12 . The support elements  36  will typically be of spring steel or the like and the connecting members  14  will be flexible and inelastic or of limited elasticity. 
     As can best be seen in FIG. 5 of the drawings, each support unit  12  is connected to adjacent support units  12  to form a laterally extending network or matrix of perpendicularly and diagonally interconnected support units  12  interconnected by connecting members  14 . 
     The coil springs  26  may be connected by lacing wires (not shown) in the normal manner found in spring mattresses and the support device  200  will act to support a prone person in the manner described above. 
     It will of course be appreciated that the coil springs  26  could be included in the kind of support structure described and illustrated in FIG.  1  . 
     If desired, cross-linked support elements  36  may be included for better stability and transmission of movement from one support unit to those adjacent to it. 
     If desired, the support units can be mounted and pre-tensioned in a peripheral frame as described above. 
     Reference is now made to FIG. 6 of the drawings, in which reference numeral  300  refers generally to part of a fourth embodiment of a support device in accordance with the invention and, unless otherwise indicated, the same reference numerals used above are used to designate similar parts. 
     The support device  300  is formed as a unitary moulding of a resilient elastomeric material. The support device  300  includes support units  12  each of which includes support elements  16  which are bowed outwardly and are connected to support elements of adjacent support units  12  via integrally moulded connecting members  14 . The support device  300  includes two layers  50 , 52  of support units  12 , integrally formed on top of each other in the load direction. 
     It will be appreciated that the moulding is three-dimensional and that each support unit  12  includes a plurality of the support elements  16  arranged to approximate an octahedron in a similar fashion to the embodiment described above with reference to FIG. 1 of the drawings. 
     A hollow passage  40  is defined at the periphery of the support device  300 . If desired, a peripheral support frame (not shown) with length and breadth dimensions somewhat larger than that of the moulding may be mounted in the passage  40  in order to laterally stretch the moulding and thus provide a pre-tension to the support units  12  in the manner described above. In this embodiment of the invention, when one of the support units  12  is compressed in the load direction, the lateral expansion of the support unit  12  permits a reduction in the pre-tension in the adjacent support units  12 , as well as a corresponding lateral contraction. Further, when the support units  12  are pretensioned the lateral contraction of a support unit as a result of the reduction in the pre-tension permits the support unit  12 , by virtue of the memory of the material, to extend in the load direction. 
     If desired, instead of or in addition to the peripheral frame mounted in the passage  40 , spheres  302  or other suitably shaped oversized spacers can be used to pre-tension the moulding laterally by wedging in position as shown in broken lines in FIG. 6 of the drawings. By positioning a plurality of the spacers  302  between adjacent support units  12 , the support units  12  can be laterally pre-tensioned. The support elements  16  of adjacent support units  12  will typically be connected to the spacers  302  at diametrically opposed positions such that compression of one support unit  12  in the load direction  54  will cause an extensile loading of the adjacent support unit  12  facilitated by the rotational motion of spherical spacer  302 . 
     Naturally, the support units  12  can be connected in any suitable fashion. 
     Reference is now made to FIG. 7 of the drawings, in which reference numeral  400  refers generally to part of a fifth embodiment of a support device in accordance with the invention and, unless otherwise indicated, the same reference numerals used above are used to designate similar parts. The support device  400  consists of a plurality of laterally abutting support units  12 . Each support unit  12  is an integral moulding including an upper end  18 , a lower end  20  and two slightly bowed support elements  16  extending between the upper end  18  and lower end  20 . The upper end  18  and lower end  20  of each support unit  12  has a “dog-biscuit” or “hourglass” shape in plan view, thereby permitting adjacent support units  12  to be arranged in a “basket weave” arrangement and defining a substantially continuous upper face  42  and a substantially continuous lower face  44 . Each support unit  12  includes an integrally formed engagement formation (not shown) releasably receivable in complementary engagement formations of an adjacent support unit  12  to retain the support units  12  in a desired spacial arrangement. Each pair of support elements  16  of one support unit  12  is curved laterally outwardly, such that compression of the support unit  12  in the load direction  54  results in outward buckling of the support elements  16  and thus transverse expansion of the support unit  12 . Support units  12  having the same orientation in the basket weave pattern, are interconnected by flexible inelastic connecting members  14  connecting the support elements  16  of one support unit  12  to the support elements  16  of other adjacent support units  12 . The members  14  are configured such that they cause the interconnected support elements  16  to bow further and hence to cause the support units  12  to become pre-tensioned. Alternatively, a support element  16  of one support unit  12  may butt directly against a support element  16  of another support unit  12 . 
     As shown in FIG. 7 of the drawings, the members  14  or the abutting arrangement of support elements  16  extends through a central aperture  46  defined between the support elements  16  of an adjacent support unit  12  having an orientation different from and positioned between the interconnected support units  12 . 
     Once again, the support device  400  utilizes the properties of resiliency or material memory, causing the tendency of a lessor loaded support unit  12  to tend to return to its unloaded shape due to a reduction in the pre-tension on it when a relatively greater load is imposed in the load direction on an adjacent interconnected support unit  12 . 
     It will be appreciated that many variations in structure will be possible without departing from the scope of the invention. 
     The Inventor believes that a support device in accordance with the invention will provide a relatively even support to an irregularly shaped object which enables the support provided by a waterbed to be simulated by a mechanical arrangement.