Abstract:
The article disclosed, with method for its manufacture, is a pocketed-spring construction made by joining juxtaposed subassemblies or modules formed by the interconnection of two rows of pocketed springs at intervals of two springs or more according to the resistance to compression desired. Various module joinder techniques are shown and described.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to pocketed-spring constructions for mattresses and cushions, and particularly to a construction, and method of its manufacture, in which the unit of assembly of the springs into the construction is a prefabricated double row module of pocketed springs, itself pre-assembled from single rows of springs encased in pockets defined by transversely seaming a two-ply fabric strip.  
           [0003]    2. Description of Related Art  
           [0004]    The two-row module of pocketed springs was first shown in my U.S. Pat. No. 4,523,344, where it was used in the separately upholstered segments of a mattress comprised of multiple individual segments connected to each other only by fabric hinge connections between the separately upholstered segments. The articulatability of such a composite mattress was thought to recommend it for the adjustable bed bottoms found in hospitals and to a lesser extent in homes, but the increased material and labor cost of such mattresses, as well as other considerations, has limited its acceptance.  
           [0005]    In my prior U.S. Pat. No. 6,131,892, I introduced the concept of the double row of pocketed springs as the unit of assembly of the pocketed spring construction. As the unit of assembly of a mattress construction, a module of double rows of springs, comprising two pre-connected individual strings or bandoliers of springs, has the advantage of being stable, i.e., self-standing when placed on a surface with either face of spring-ends lowermost.  
           [0006]    Similarly, in my co-pending application for U.S. patent Ser. No. 09/675,788, I introduced the employment of resilient foam elements in single-row bandolier form joined together in two-row modules for the same use as the two-row modules of pocketed wire or coil springs, and in the further orientation of the foam elements with their axes parallel to the plane of the construction, an unconventional orientation permitted by their omni-directional resilience, and useful where the flexure of mattress sections is a requirement.  
           [0007]    In a number of my earlier patents, I had disclosed some of the then-discovered effects upon the resilience of pocketed wire coil springs of the various ways the individual rows of pocketed springs were assembled into construction.  
           [0008]    For example, U.S. Pat. No. 4,234,984 dealt with a mode of assembly in which successive individual rows of pocketed springs were connected together seriatim by an ultrasonic welding apparatus having multiple welding probes. These were spaced at two spring intervals, and were indexed by one spring from row to row to unite the springs quite intimately in overlapping quadratic patterns, i.e., with each spring finding itself a member of two, four-spring “clover leaf” clusters by virtue of indexed connections between successive rows. This method of construction placed each spring in intimate and cooperative association with six other springs in mutual reinforcement which stiffened the resistance of the assembly to local load.  
           [0009]    In U.S. Pat. No. 4,451,946, I disclosed the further discovery that this stiffness-modifying effect can be enhanced by modifying the extent and placement of the inter-row connections, which in U.S. Pat. No. 4,234,984 had taken the form of two “button” welds in the slackest part of the pocket fabric near the ends of the springs. Moved from the spring ends to the center of the transverse seams between successive pockets, the resistance of the construction to compression is increased by an amount variable with the vertical length of the inter-row seal.  
           [0010]    It may be appreciated from my related U.S. Pat. Nos. 4,401,501 and 4,566,926 that apparatus for the assembly of mattress constructions from single strings or bandoliers of pocketed springs, particularly if automated for practicable production rates, can be complex and therefore expensive, owing to the necessity of fixturing each new flexible string of springs, in relation to the string of springs last joined to the construction, in order to effect the inter-row connections, whether they be made by welding the rows together at the webs between springs, as in U.S. Pat. No. 4,401,501, or by the direct cheek-to-cheek adhesion of the pockets of the springs of one row to those of the next, using hot melt or other adhesive, as in my U.S. Pat. No. 4,578,834.  
           [0011]    Out of the very complexity of handling the flexible strings of springs in row by row assembly of pocketed spring constructions grew the stable self-supporting double row of springs as the unit of assembly, joined together as a unit preferably but not necessarily by welding, which can be made in relatively simple apparatus, and severed into relatively rigid modules of length suitable for mattresses. These can be readily handled manually and assembled manually upon a work table to form a handleable unitary construction for upholstery by any of the procedures known to the art.  
         SUMMARY OF THE INVENTION  
         [0012]    The present invention has multiple aspects, one involving the manner of connecting two individual rows of springs together to form the continuous double row of springs from which the two-row modules are severed, and another the manner of connecting contiguous coextensive double-row modules to form the construction. Both can be varied to alter the inherent resilience of the individual springs in their collective role.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is an elevational view of a short segment of a double row of pocketed springs, having two successive inter-row connections at a two-spring interval, as updated from the disclosure of my U.S. Pat. No. 6,131,892;  
         [0014]    [0014]FIG. 2 is a plan view of the double-row segment of FIG. 1;  
         [0015]    [0015]FIGS. 3 a ,  3   b , and  3   c  are plan view diagrams of three forms of double-row spring modules in which the inter-row connections are spaced at 2, 3, and 4 spring intervals, respectively;  
         [0016]    [0016]FIG. 4 is a plan view of a connected series of foldable double-row spring modules defined in a double-row continuum by periodic severance of the web connections between the springs of a single row, alternating between rows;  
         [0017]    [0017]FIG. 5 a  illustrates alternate forms of joining multiple double-row spring modules in a larger “construction” for mattresses or the like; and  
         [0018]    [0018]FIGS. 5 b  and  5   c  illustrate further ways of securing the double-row modules in larger assemblies or “constructions”. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0019]    As contemplated heretofore, and as shown in FIGS. 1 and 2, essentially as earlier illustrated in my U.S. Pat. No. 6,131,892, the two-row module  10  of pocketed springs  12  was fabricated by connecting the fabric pocket material of the constituent strings or rows together at intervals of two-springs therealong, making the connections  14 , hidden in FIG. 1 but shown in FIG. 2, at the location of the transverse seams  16  of the fabric between the pockets.  
         [0020]    The joinder  14  of the fabric of the two rows by connecting the webs between adjacent individual springs rotates the springs adjacent the connection, the two springs  12  between successive connections  14  being rotated in opposite directions to place the seam or seams  16  between their respective pockets on the outsides of the double row (FIG. 2). The connection of the two constituent rows in this fashion also draws the pocket fabric more tightly about the individual springs, increasing their resistance to compression, as explained in my U.S. Pat. No. 4,451,946, column 4, lines 23 et seq., an effect which is dependent in amount upon the vertical extent of the inter-row connection, and upon its placement and distribution.  
         [0021]    For that reason, and to facilitate the severance of the double row of springs into discrete modules, I prefer to form the pockets in the fabric strip by at least two spaced transverse seams  16  so that the integrity of the pockets adjacent to the severance of the strip is preserved by cutting the fabric web between the two spaced transverse seams  16 , leaving at least one seam in the fabric tab  18  at the point of severance.  
         [0022]    Given the spring-stiffening effect of spacing the inter-row connections at intervals of two springs, the two-row module can be conversely softened by increasing the interval between inter-row connections to three springs or more. The greater spacing between connections reduces the pocket tension induced by the inter-row connections.  
         [0023]    For example, as shown in FIG. 3 a , a two-row module  20  for transverse orientation in a mattress of single bed width (39-40 inches) requires a module fourteen springs in length at a spring diameter of 2.75 inches, or seven four-spring clusters with seven inter-row connections  24  of the two constituent rows, when connected at two-spring intervals. For any given form of inter-row connections, their placement at two-spring intervals produces the greatest resistance to compression other factors being equal.  
         [0024]    If the spacing of inter-row connections is increased, however, the resistance to compression of the module  20  overall is reduced, resulting in a softer mattress. Returning to the single bed mattress for illustration, the interval between inter-row connections  24  may readily be increased to three springs, as shown in FIG. 3 b , with but five rather than the seven inter-row connections  24  which occur when the interval is but two springs.  
         [0025]    The single bed module  20  is equally divisible into four-spring intervals, with four inter-row connections  24 , as shown in FIG. 3 c , for a further softening effect. In each case, it is preferred that an inter-row connection  24  be made between the first four springs at either end of the module  20 , necessitating a two-spring interval when the module is formed by severance from a two-row chain, to define the end of one module and the beginning of the next. The module is separated from the double-row chain of springs by cutting the web between the springs of the two-spring interval at every cutting interval of fourteen springs in the illustrated case.  
         [0026]    Therefore, continuing with that example, the stiffest module, that of FIG. 3 a , will result from consecutive two-spring intervals between inter-row connections. The softest module will result from four-spring intervals, FIG. 3 c , which in turn will require that inter-row connections in a continuous two-row string be made at a regular periodic spring-interval cycle of 2-4-4-4-2-4-4-4-2-4-4-4-2 (etc.). When the continuous two-row string is severed into modules by cutting the string between the springs of a two-spring interval, the spring count for a module fourteen springs long becomes 1-4-4-4-1, as in FIG. 3 c . Similarly for a module of intermediate stiffness, the periodic spring interval cycle must be 2-3-3-3-3-2-3-3-3-3-2 (etc.), which when severed into modules fourteen springs long, as described, results in a spring group sequence of 1-3-3-3-3-1, as in FIG. 3 b . In each case, two unsevered consecutive cycles will produce a module of length appropriate for a king size mattress (80 inches wide), or for that matter, for any mattress of 80-inch length, if the modules two cycles in length are oriented lengthwise of the mattress.  
         [0027]    For mattresses of the 54-inch and 60-inch intermediate widths, some accommodation of the combination of spring intervals between inter-row connections may be required for transverse orientation, if more than a two-spring interval is desired.  
         [0028]    Whatever cycle may be desired, it is within the capability of the art to adjust the control mechanism of the apparatus for sequentially connecting two unstable single-row bandoliers of pocketed springs into a stable self-standing double row, to execute a repetitive series of inter-row connections in predetermined but variable spring-interval sequence.  
       Intermodular Connection  
       [0029]    As heretofore described, the inter-row connection of unstable, flexible, single-row bandoliers into stable double-row modules has not been specified other than by reference to my prior patents, which contemplated inter-row connection of a variety of forms from ultrasonic thermal welding, where the nature of the pocket sheeting will permit, to the use of mechanical connectors such as stitching or staples, where the pocket sheeting is not thermally weldable.  
         [0030]    The more recent development of hot-melt adhesives, used in my prior U.S. Pat. Nos. 4,566,926 and 4,578,834 for the cheek-to-cheek connection of adjacent spring rows to one another, seriatim, in the fabrication of a spring core or construction, may suggest the use of that form of connection of two single rows of springs together to form stable double-row modules. However, the mere tangential or “cheek-to-cheek” contact of the rows so connected, although possible, effects no further tensioning of the pocket sheeting about the springs, such as can be realized by row-to-row connection of the pocket sheeting webs between the transverse, pocket-defining seams. The use of hot-melt adhesive for the seam-to-seam connections  24  of two single rows to each other to form a double-row module  20  is clearly feasible, although from the standpoint of ease of manufacture, is less preferable than the instantaneous connection of the two spring rows together by ultrasonic thermal welding of the sheeting of two rows together at their transverse seams.  
         [0031]    However the two-row modules  20  are achieved, their further assembly into mattress or cushion cores may vary according to the amount of handling of the construction that is required before final upholstery.  
         [0032]    In the simplest case, the placement of the modules side-by-side in an appropriately sized box, followed by an adhesive spray on the upper surface of the assembly, and the application of fabric sheet to the sprayed adhesive, may suffice.  
         [0033]    If the suggested “box” were fabricated of polyfoam and a polyfoam sheet substituted for the fabric sheet, the polyfoam upholstered core is ready for insertion immediately into a pre-sewn cover on a filling machine.  
         [0034]    Where, however, the factory layout, or the desired upholstery procedure, or other considerations, require it, the present invention contemplates the connection of successive double-row modules of pocketed springs to each other seriatim for their assembly into an entire mattress core, or to sections thereof where zones of different degrees of softness are desired along the length of the mattress, or between its longitudinal half-sections.  
         [0035]    In one novel approach to fabrication of the two-row modules into a mattress or cushion construction, as in FIGS. 3 a ,  3   b , or  3   c , for example, the double-row string of pocketed springs, as they issue from apparatus which connects the two strings of individual pocketed springs together at their respective pocket-defining transverse seams at intervals of two or more springs therealong, are partially severed from the double-row string by a single transverse cut of the pocket fabric made between the spaced lines of seam welds on the outside of the four-spring grouping defined between two adjacent inter-row connections made at the two-spring interval, and which is made successively on opposite sides of the double-row string.  
         [0036]    The single-sided cut described leaves the fabric on the opposite side of the two-row string intact to serve as a hinge  28  about which two successive modules are foldable into juxtaposition, being successively foldable in opposite directions, as indicated diagrammatically in FIG. 4.  
         [0037]    The folding process may be continued until a construction of the desired size, or number of modules, is obtained, be it a mattress-size construction, or a lesser one for a mattress-construction zonal segment, or a cushion for an upholstered item of furniture.  
         [0038]    Where intermediate transfer or other handling of the construction prior to upholstering is to be anticipated, further attachment of the folded, juxtaposed modules  20  to each other may be effected by application of adhesive  30  to the contacting surfaces of the juxtaposed modules, as in FIG. 5 a , near or at the end of the intermodular joint opposite the hinge  28  and at one or more intermediate locations, depending upon the length of the modules. Referring back to the softer modules created by altered spacing of the inter-row connections, i.e., of FIGS. 3 b  and  3   c , I prefer to make the intermodular adhesive connections between one or both of the springs of the respective modules which flank the inter-row connections  24  of the modules, whether the modules are of the hinged variety, or otherwise separate from each other prior to assembly.  
         [0039]    Similarly, in the absence of the aforedescribed hinge connections between modules, i.e., where the modules are discrete, I prefer to apply a spot of adhesive between the end springs of the respective juxtaposed modules, and between as many intermediate springs thereof, i.e., one, two, or three as the handling of the unupholstered construction may require. Given the high tensile strength of the non-woven synthetic fabrics available for spring-pocket service today, the number of intermediate intermodular attachments I find desirable are: one for a single bed mattress, two for a double bed mattress or queen-size, and three for a king-size mattress. These references are to sizes customary in the United States of America at the present time, and in fact are subject to some variation both here and abroad. Moreover, the number of intermodular attachments may desirably be increased if the gauge, or thickness, of the fabric should be reduced, for whatever reason.  
         [0040]    [0040]FIG. 5 a  illustrates yet another and alternative form of securing the modules in assembled relation prior to upholstery, whether of the hingedly connected or the discrete form of module, namely, two (or more) adhesive tapes  32  spanning the modules transversely thereof, and adhered to the pocket fabric at the ends of the spring pockets contacted, and preferably overlapping the outermost modules, as shown in FIG. 5 a . In the case of the assembly of discrete modules, it may be desirable to apply a tape or tapes in similar fashion to the opposite face of the construction as well, in effect encircling the assembly.  
         [0041]    A further variant is shown by FIG. 5 b , where the adhesion of juxtaposed modules is effected by double-sided adhesive tape  34 , which is illustrated in connection with the hinged form of module in FIG. 5 b , but may be used at both ends of each contacting surface of any discrete module with the next, as well, and at the intermediate interface locations earlier specified in connection with the separately applied adhesive suggested by FIG. 5 a.    
         [0042]    For modular pocketed spring construction of lesser size, particularly as for upholstery cushions or cushioning, or even the somewhat larger zonal segments of mattresses of stiffness variable along the length of the mattress, I may also use a single-sided adhesive tape  36  spanning the ends of the juxtaposed double-row modules, as shown in FIG. 5 c . The tape  36  may completely encircle the assembly, or be applied only to the ends of the modules, preferably with at least some overwrap of the corner to aid in anchoring the tape. Whether the full wrap of tape is used or two partial wraps engaging essentially only the opposite ends of the modules, would likely be chosen for a production operation on the basis of time and motion considerations balanced against material cost, as the necessity of a full wrap is obviated by the strength of the pocket fabric in the long direction of each module.  
         [0043]    In the foregoing description, I have outlined my latest contemplations for the assembly of mattress and cushion cores from stable double-row modules of pocketed springs, prefabricated from flexible single bandoliers or strings of individually pocketed springs, which can be difficult to handle, and require complex machinery for their use as the spring element from which mattress size constructions are assembled. A distinct advantage of the stable two-row module is its ease of handling, which in turn adapts it to the assembly of constructions without the need for capitol-intensive apparatus, thereby making it possible for lesser organizations to compete effectively in the marketplace with a first rate product.  
         [0044]    The features of the invention believed new and patentable are set forth in the following claims.