Abstract:
A simply constructed, inexpensive underlay ( 10 ) for which the underspringing arrangement ( 12 ) is formed in the simplest case by a plastic sheet ( 15 ), which is selectively reinforced by supplementary crosslinking of the plastic of the plastic sheet ( 15 ). This crosslinking provides the plastic sheet ( 15 ) with supplementarily consolidated, more stable regions ( 20 ), which support the mattress ( 11 ). If required, the plastic sheet ( 15 ) having supplementarily consolidated regions ( 20 ) may be assigned spring strips ( 14 ). It is also conceivable to integrate the underspringing arrangement ( 12 ) in the mattress ( 11 ). The underspringing arrangement ( 12 ) formed according to the invention can be easily produced, thereby creating a low-cost underlay ( 10 ) with good resilient properties.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Technical Field  
         [0002]     The invention relates to an underlay for the human body with at least one mattress of foam plastic or with at least one mattress of foam plastic and an underspringing arrangement. Furthermore, the invention relates to a method for producing an underlay for the human body, the underlay being formed by at least one mattress of foam plastic and an underspringing arrangement.  
         [0003]     2. Prior Art  
         [0004]     Underlays of the type referred to here are used in the case of beds and furniture for sitting and lying on. The underlays are intended to offer sleeping, lying and sitting comfort appropriate for the requirements.  
         [0005]     In the simplest case, such an underlay comprises a mattress, which rests directly on a framework, for example a bed. Such underlays have minimal sleeping, lying and sitting comfort. High-grade underlays have in addition to the mattress an underspringing arrangement, which offers a resiliently compliant, elastic support for the mattress. Known underspringing arrangements of this type require a complex construction, making the underlays expensive.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     The invention is based on the object of providing a simple, inexpensive underlay, which nevertheless offers a high degree of sleeping, lying and/or sitting comfort for the human body. Furthermore, the invention relates to a method for the simple and inexpensive production of an underlay for the human body.  
         [0007]     An underlay serving to achieve this object comprises at least one mattress of foam plastic, characterized in that supplementarily consolidated regions are assigned to the mattress. Accordingly, the mattress is assigned supplementarily consolidated regions of its foam plastic. These supplementarily consolidated regions harden or stabilize the material of the mattress at selected locations. As a result, the underspringing arrangement can be virtually integrated in the mattress.  
         [0008]     Another underspringing arrangement for achieving the stated object comprises at least one mattress of foam plastic and an underspringing arrangement, characterized in that supplementarily consolidated regions are assigned to the underspringing arrangement. Accordingly, the underspringing of the mattress is assigned supplementarily consolidated regions. Such a separate underspringing arrangement is simple to manufacture.  
         [0009]     The supplementarily consolidated, in particular supplementarily crosslinked, regions form selectively hardened parts of the mattress or of a layer of plastic supporting the latter, which obviates the need for a complex underspringing arrangement. The hardened regions can be easily formed by supplementary consolidation from the material of the mattress or an additional layer of plastic. As a result, an underlay which is equivalent to a mattress lying on a complex underspringing arrangement with regard to the sleeping, lying and sitting comfort is obtained in an inexpensive way.  
         [0010]     If the regions selectively hardened by supplementary crosslinking are formed from a separate layer of plastic, this may be a foam plastic sheet or else a sheet of unfoamed plastic, in particular an elastomer sheet. An underspringing arrangement for the mattress can be formed from this very easily by simple supplementary crosslinking of the plastic, whereby the selectively hardened regions for supporting the mattress are created. A curable polymer also comes into consideration in particular as the plastic for the plastic foam.  
         [0011]     In the case of a preferred form of the invention, the underlay has supporting elements. The supporting elements are assigned to the mattress, to be precise in such a way that they are located in the mattress or under the mattress. The supporting elements form an additional support for the mattress.  
         [0012]     According to a further refinement of the invention, the supporting elements are assigned to the selectively hardened or supplementarily consolidated regions of the mattress or its integrated underspringing arrangement or a separate underspringing arrangement. In this case, the selectively hardened, in particular supplementarily hardened or supplementarily crosslinked, regions serve as supporting locations or load distributors, in that they introduce the load of the person resting on the mattress via the foam plastic of the mattress into the supplementarily consolidated regions and from there into the supporting elements. In this way, the supplementarily hardened regions form an underspringing arrangement together with the supporting elements.  
         [0013]     According to a preferred refinement of the invention, the underspringing arrangement formed by the supplementarily hardened or supplementarily consolidated regions and the supporting elements, but also, if appropriate, just by the supplementarily consolidated regions, is an integral part of the mattress. In particular when no supporting elements are provided, the underlay according to the invention substantially comprises only the mattress with its supplementarily consolidated regions. It is also conceivable to form the underspringing arrangement separately. Then the elastic underspringing arrangement forms the underlay together with the mattress, the underspringing arrangement supporting the mattress.  
         [0014]     According to a preferred refinement of the invention, the selectively hardened regions of the mattress or of the underspringing arrangement are connected to the supporting elements. This connection preferably takes place with positive engagement, but may also be additionally or alternatively created by adhesive bonding, welding or the like. The connection of the supporting elements to the supplementarily consolidated or supplementarily crosslinked regions leads to the supporting elements and the supplementarily consolidated or reinforced regions forming a functional unit which is effective altogether as an underspringing arrangement, to be precise independently of whether this underspringing arrangement is arranged separately under the mattress or is an integral part of the same.  
         [0015]     The selectively hardened, in particular supplementarily consolidated, regions are formed as punctiform and/or elongated or strip-like three-dimensional structures. The punctiform structures may be formed as mushroom- or dome-like structures, while the elongated structures are formed in a strand-like manner. The strand-like structures preferably extend continuously over the entire length or width of the underlay, in particular of the mattress. The strand-like structures then form a continuous reinforcement of the mattress or of the underspringing arrangement lying under it. On account of the strand-like structures, it may be possible to dispense with additional supporting elements. In the latter case, the underlay in its simplest form merely comprises the mattress, in that the selectively supplementarily hardened regions, in particular the strand-shaped structures, are an integral part of the same. Such an underlay can be produced particularly easily and inexpensively.  
         [0016]     The supporting elements are preferably formed as strips, in particular spring strips, extending continuously over the entire width or length of the mattress. As a result, good stabilization of the mattress is brought about. If all or some of the supporting elements are formed as spring strips, they form part of a resilient supporting structure, in particular an underspringing arrangement, of the mattress, to be precise even when the underspringing arrangement is integrated in the mattress with the strips and/or spring strips and also the supplementarily consolidated regions.  
         [0017]     If the underspringing arrangement is formed as an integral part of the mattress, the supplementarily hardened regions and/or the supporting elements, to be precise strips or spring strips, are arranged in the region of the underside of the mattress. As a result, the mattress is supported in a way similar to how it is supported by a separate underspringing arrangement. In this case, the supplementarily hardened regions expediently extend from the underside of the mattress. The supporting elements, that is to say the strips and/or spring strips, are also inserted or pushed from the side into corresponding recesses in the underside of the mattress, which extend through the supplementarily hardened punctiform or elongated structures.  
         [0018]     A method for achieving the object mentioned at the beginning has the measures of the underlay being formed by at least one mattress of foam plastic and an underspringing arrangement, characterized in that the underspringing arrangement is formed by at least one layer of plastic or foam plastic, and regions of the layer of plastic or foam plastic are supplementarily consolidated by subsequent selected crosslinking. Accordingly, the underspringing arrangement integrated in the mattress or separate underspringing arrangement is formed from a layer of plastic or foam plastic, regions of the at least one layer of plastic or foam plastic being supplementarily consolidated by subsequent crosslinking. This allows the underspringing arrangement to be formed in the simplest way by the supplementary crosslinking and accompanying curing of selected regions of the layer of plastic or foam plastic. As a result of the invention, structural changes or additional parts are not required to form the underspringing arrangement.  
         [0019]     A particularly simple underlay is obtained if the underspringing arrangement is formed from a part, in particular a lower part, of the foam material of the mattress. The underspringing arrangement then does not even require an additional plastic material, because the foam plastic that is required in any case to form the mattress is used to form the supplementarily consolidated regions.  
         [0020]     The subsequent crosslinking of the foam plastic of the mattress or of an additional layer of plastic to form a separate underspringing arrangement takes place thermally. For this purpose, electron beams, infrared beams or ultraviolet light may be used. These allow a targeted effect to be produced on the plastic, in particular foam plastic, in certain regions, so that punctiform or strand-like supplementarily consolidated structures are selectively created at the intended locations, but supplementary consolidation is not carried out on the entire mattress or the entire additional layer of plastic, as a result of which the supplementarily consolidated regions do not appreciably influence, in particular do not significantly reduce, the elasticity of the mattress or of the additional layer of plastic. These structures are either sufficient on their own to form the underspringing arrangement or they are supported on additional supporting elements such as elongated strips, in particular spring strips, the supplementarily consolidated regions or structures having the effect that the force exerted on the mattress by the person lying on it is introduced into the supporting elements over a large surface area. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     Preferred exemplary embodiments of the underspringing arrangement according to the invention and of the method for producing the same are explained in more detail below on the basis of the drawing, in which:  
         [0022]      FIG. 1  shows a partial longitudinal section through an underlay according to a first exemplary embodiment of the invention.  
         [0023]      FIG. 2  shows a partial longitudinal section through an underlay according to a second exemplary embodiment of the invention.  
         [0024]      FIG. 3  shows a perspective partial view of the underlay of  FIG. 2 .  
         [0025]      FIG. 4  shows a perspective partial view analogous to  FIG. 3  of an underlay according to a third exemplary embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]     The figures show parts of various underlays for furniture for sleeping, lying or sitting on. The respective underlay is supported by a frame of the furniture, for example a bed frame. The underlay receives a person, who lies on it in the case of a bed or lounger or sits on it in the case of a chair or armchair. To increase the sleeping, lying or sitting comfort, the underlay is intrinsically elastic and/or elastically deformable, in that it at least partially bends.  
         [0027]      FIG. 1  shows a first exemplary embodiment of an underlay  10 , which is formed by a preferably rectangular mattress  11  and a separate, elastically compliant underspringing arrangement  12 . The mattress  11  rests with its underside  13  on the underspringing arrangement  12 . The mattress  11  shown here is formed in one piece from foam plastic. The mattress  11  may, however, also be made up of more than one part, to be precise of mattress parts lying one behind the other in the longitudinal direction and/or of a number of layers or part-mattresses lying one on top of the other. If the mattress  11  is formed by a number of layers lying one on top of the other, they may be connected to one another by positive engagement and/or adhesive bonding or be arranged in a common covering (not shown). The mattress  11  of the exemplary embodiment shown can consequently be formed conventionally in any desired customary way.  
         [0028]     In the case of the exemplary embodiment shown, the separate underspringing arrangement  12  of the underlay  10  is formed in a special way according to the invention. The underspringing arrangement  12  has a number of supporting elements, which are formed here as strips, to be precise in particular as spring strips  14 . A number of identical spring strips  14  are arranged such that they run parallel to one another with a spacing. The spring strips  14  extend continuously along under the mattress  11  in a transversely directed manner. Furthermore, the underspringing arrangement  12  has a layer of plastic, which is preferably formed as a plastic sheet  15 . The plastic sheet  15  may be formed from foam plastic or else from compact plastic, in particular an elastomer. In the exemplary embodiment shown here, the plastic sheet  15  has a contour undulating in the longitudinal direction of the underlay  10 , thereby creating successive curvatures  16  and  17 , which are continuously profiled along the spring strips  14 , so that they have approximately the same cross section along the spring strips  14 . The plastic sheet may, however, also be curved in the transverse direction of the mattress  11 . One type of curvature  16  extends over each spring strip  14 , while the other type of curvature  17  is located between two adjacent spring strips  14 . The upper vertices  18  of the curvatures  16  and  17  lie against the underside  13  of the mattress  11 . Between successive curvatures  16  and  17 , the plastic sheet  15  has double-layer, approximately U-like connecting regions  19 , which lie against opposite sides of the spring strips  14 .  
         [0029]     According to the invention, the plastic sheet  15  is partly supplementarily crosslinked and thereby cured. As a result, the plastic sheet  15  has supplementarily consolidated regions  20 . These are illustrated in  FIG. 1  by a crosshatching. It is evident from this that the supplementarily consolidated regions  20  extend substantially over the curvatures  16  assigned to the spring strips  14  and the connecting regions  19  adjoining them on both sides. The supplementarily consolidated regions  20  are specifically assigned only to the spring strips. It is also conceivable for the middle part of the curvatures  16 , which rests on the spring strips  14 , not to be formed as a supplementarily consolidated region  20 . In the supplementarily consolidated regions  20 , the plastic sheet  15  has a greater strength and also rigidity. This produces a positively engaging solid connection of the plastic sheet  15  in the regions of the curvature  16  to the spring strips  14 . The supplementarily consolidated regions  20  also contribute to the stabilization of the curvatures  17  of the plastic sheet  15  between the spring strips  14 , which are not supplementarily consolidated. This stabilization has the effect that the force exerted on the mattress  11  by the person lying or sitting on it is introduced more uniformly into the underspringing arrangement  12 . Outside the supplementarily consolidated regions  20 , the plastic sheet  15  has its original, unreduced strength and elasticity. These properties are changed in the supplementarily consolidated regions  20  by the supplementary crosslinking. In particular, the plastic sheet  15  or the layer of plastic in the supplementarily consolidated regions has a greater strength and rigidity.  
         [0030]     In the production of the underspringing arrangement  12 , the following procedure is adopted: the foamed or unfoamed plastic sheet  15 , made preferably of a curable polymer, is firstly placed in a wave-like manner over the spring strips  14  and subsequently thermally consolidated in certain regions, that is in a targeted manner, in that the supplementarily consolidated regions  20  are specifically exposed to energy beams. This causes a partial, that is local, supplementary crosslinking of the plastic, whereby the latter cures in the irradiated, supplementarily consolidated regions  20 . The selective thermal treatment of the plastic sheet  15  may take place by electron beams, infrared beams or else ultraviolet light. For this purpose, the light or the beams is/are selectively directed only onto the regions  20  that are to be supplementarily consolidated or supplementarily crosslinked. The spring strips  14  are preferably formed from a plastic which is not cured or supplementarily crosslinked under the influence of the thermal treatment of the plastic sheet  15 , so that it remains excluded from the thermal treatment or supplementary crosslinking of the regions  20 . Those regions of the plastic sheet  15  which are not to be supplementarily consolidated are not subjected to supplementary thermal treatment. These are, in particular, the curvatures  17 , in the region of which the plastic sheet  15  substantially retains its original strength and elasticity. This strength is less than in the supplementarily consolidated regions  20 . The elasticity of the plastic sheet  15  outside the supplementarily consolidated regions  20  is also greater than in the supplementarily consolidated regions  20 . The supplementary consolidation by supplementary crosslinking may be performed to such a degree that, in the supplementarily consolidated regions  20 , the plastic sheet  15  then only has a very small residual elasticity or substantially no elasticity at all.  
         [0031]     Alternatively, it is conceivable for the plastic film  15  to be thermally supplementarily crosslinked and cured before it is placed onto the spring strip  14 , to be precise only in those regions of the plastic sheet  15  which correspond to the supplementarily consolidated regions  20  above the spring strips  14  running transversely in relation to the longitudinal direction of the underlay  10 .  
         [0032]      FIG. 2  shows an underlay  21  according to a second exemplary embodiment of the invention. This underlay  21  substantially comprises only the mattress  22 . A separate underspringing arrangement  12 , as in the case of the exemplary embodiment of  FIG. 1 , is not present in the case of the underlay  21 . Rather, this underspringing arrangement is integrated in the mattress  22 , to be precise in an underside region of the same.  
         [0033]     In  FIG. 2 , the mattress  22  is formed in one piece or one layer. It may, however, also be formed in more than one piece or more than one layer, as described further above in connection with the exemplary embodiment of  FIG. 1 .  
         [0034]     In addition to the mattress  22 , the underlay  21  has supporting elements. The supporting elements are formed by strips, these being spring strips  23  in the exemplary embodiment shown. The spring strips  23 , running parallel with a spacing, are assigned to the underside  24  of the mattress  22 . In the present case, the spring strips  23  lie in the mattress  22 , to be precise in such a way that they are surrounded by the mattress  22  apart from a partial region of their underside. The spring strips  23  may, however, also be completely embedded in the mattress  22 , so that they are entirely surrounded by the foam plastic of the mattress  22 . In this way, the spring strips  23  extending transversely in relation to the longitudinal direction of the mattress  22 , continuously over the entire width of the same, are for the most part embedded in the mattress  22 , to be precise in such a way that they lie within the outlines of the mattress  22 . However, it is also conceivable for the spring strips  23  to lie only partially within the mattress  22  or to be located completely under the underside  24  of the mattress  22 .  
         [0035]     The mattress  22  is formed completely from foam plastic. Partial regions of the foam plastic are made harder by thermal supplementary crosslinking than the original remaining part of the foam plastic of the mattress  22 . In the exemplary embodiment shown, the supplementarily consolidated regions  25  created by thermal supplementary consolidation are assigned to the spring strips  23 . For this purpose, the supplementarily consolidated regions  25  extend over those parts of the mattress  22  which surround the respective spring strip  23  in cross section ( FIG. 2 ). The size of the respectively supplementarily consolidated region  25  corresponds to the requirements. It can be varied as need be. The supplementarily consolidated regions  25  assigned to each spring strip  23  have the effect that the foam plastic of the mattress  22  is hardened in certain regions, that is only partly, whereby reliable retention, if appropriate with positive engagement, of the spring strips  23  in the mattress  22  is ensured. Furthermore, the supplementarily consolidated regions  25  have the effect that the force exerted on the mattress  22  is introduced into the spring strips  23  over a large surface area, whereby stable support of the mattress  22  on the spring strips  23  comes about even without a separate underspringing arrangement  12 . In the case of the underlay  21 , this underspringing arrangement is virtually integrated in the mattress  22  and is consequently part of the same.  
         [0036]     The supplementarily consolidated regions  25  are three-dimensionally formed. The supplementarily consolidated regions  25  shown in  FIG. 3  are formed in a punctiform manner, to be precise as mushroom- or dome-like structures. A number of these regions  25  supplementarily consolidated in a punctiform manner follow one another, either lying directly one against the other or spaced apart from one another, along the spring strip  23 , the spacings between the punctiform structures for forming the supplementarily consolidated regions  25  being variable in a way corresponding to the requirements.  
         [0037]      FIG. 4  shows supplementarily consolidated regions  26  according to an alternative exemplary embodiment of the invention. Here, each spring strip  23  is assigned a continuous, elongated supplementarily consolidated region  26 . Such a supplementarily consolidated region  26  forms a strand-like structure, which extends over the entire width of the mattress  22  or length of the spring strip  23 , to be precise uninterruptedly. The supplementarily consolidated regions  26  thus form a partial tube, which surrounds the cross section of the respective spring strip  23  to the extent that the latter is enclosed by the mattress  22 .  
         [0038]     The production of the underlay according to FIGS.  2  to  4  takes place by a mat corresponding to the shape of the mattress  22  being cut out from a block of foam plastic. Transversely directed, continuous grooves, which are large enough to receive the spring strips  23 , if provided, are then cut into the underside  24  of the foam plastic mat at locations where the spring strips  23  are later to be accommodated, to form the mattress  22 . The spring strips  23  are then placed into these grooves and supplementary consolidation of the originally relatively soft foam plastic is subsequently performed selectively where the supplementarily consolidated regions  25  and  26  are intended. For this purpose, the foam plastic of the mattress  22  is partially and selectively cured, in that it is thermally supplementarily crosslinked, to be precise in the way described in detail in connection with the exemplary embodiment of  FIG. 1 , that is by electron beams, infrared beams and/or UV light. The spring strips  23  may, however, also be pressed into the underside  24  of the mattress  22 , that is the foam plastic mat serving to form the same, obviating the need for grooves to be cut in.  
         [0039]     Alternatively, it is conceivable to perform the supplementary crosslinking of the plastic foam of the mattress  22  before the placement of the spring strips  23  into the grooves cut into the underside  24  of the mattress  22 , and thereby form the punctiform supplementarily consolidated regions  25  or the strip-shaped supplementarily consolidated regions  26 . Subsequently, the spring strips  23  are pushed or pressed or clamped into the downwardly open grooves remaining in the regions  25  and  26  even after the supplementary consolidation. In addition, adhesive bonding and/or welding of the spring strips  23  to the mattress  22 , in particular the supplementarily consolidated regions  25  and  26 , may take place.  
         [0040]     The invention is also suitable for underlays (not shown) which do not have supporting elements, so that the spring strips  14  or  23  shown in FIGS.  1  to  4  are entirely absent or else only partly absent. The separate underspringing arrangement, or underspringing arrangement integrated in the mattress, is then formed just by the supplementarily consolidated regions  25  or  26  or the plastic sheet  15  with supplementarily consolidated regions  20 . In this case, the supplementarily consolidated regions  20  of the plastic sheet  15  need not run continuously in a strand-like manner to form the underspringing arrangement; they may also be present in a punctiform manner (as in the case of the exemplary embodiment of  FIG. 3 ), so that the supplementarily consolidated regions  20  are formed by mushroom- or dome-like local structures. As a departure from the exemplary embodiment shown, the structures may have any desired other shape.  
       List of Reference Numerals  
       [0000]    
       
           10  underlay  
           11  mattress  
           12  underspringing arrangement  
           13  underside  
           14  spring strip  
           15  plastic sheet  
           16  curvature  
           17  curvature  
           18  vertex  
           19  connecting region  
           20  supplementarily consolidated region  
           21  underlay  
           22  mattress  
           23  spring strip  
           24  underside  
           25  supplementarily consolidated region  
           26  supplementarily consolidated region