Patent Publication Number: US-6708357-B2

Title: Corner piece for a soft-sided mattress

Description:
BACKGROUND OF THE INVENTION 
     The device of the present invention pertains to reinforcing the corners of a mattress having soft sides, such as a waterbed or airbed. 
     Fluid-filled beds are quickly gaining popularity as an alternative sleeping surface to standard spring-based mattresses. This trend began with waterbeds and recent advances in airbed technology have placed airbeds in the forefront of fluid-filled mattresses. 
     Initial waterbed designs provided a bladder placed into a bed frame having a cavity formed by a solid base and four rigid walls. The bladder was then filled with water and laterally constrained by the rigid walls. The need for a soft-sided waterbed was quickly illuminated as people began bruising their legs on the rigid sides of the bed and found sitting on the edge of the bed extremely uncomfortable. 
     Soft-sided waterbeds, and now airbeds as well, substitute the rigid side walls of the previous designs with foam walls. The bladders are baffled so that less lateral support is required. The soft, foam sides more closely simulate a conventional spring mattress and virtually eliminate the problems associated with hard-sided waterbeds. 
     However, the foam sides present a unique problem. Soft foam is an inherently poor construction material. In order to form the soft border, four pieces of foam are laid around the bladder, inside the mattress cover, in such a manner as to form butt joints at the corners. In order to join the members to each other, one solution covers the foam members with a material to which a hook and loop fastener is attached. The hook and loop fastener joins the two members forming each butt joint. 
     Over a relatively short period of time, the butt joint formed using a hook and loop fastener tends to shift. This shifting gives the corners of the mattress a somewhat soft, sloppy appearance. Moreover, these individual foam covers represent a significant unit cost, which is uneconomical considering their ineffectiveness. 
     It would thus be desirable to provide a low cost mechanism for joining two foam side members together to form a butt joint that will maintain its shape over time. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a method and mechanism for maintaining a desired orientation of the abutting sides of a soft-sided, fluid-filled bed. The mechanism is inexpensive, easy to manufacture, easy to assemble by the consumer, and usable in any of the four corners of the mattress. 
     The mechanism generally comprises a plastic 90 degree channel defined by an outer wall, an inner wall, and a bottom. The outer wall is high enough to prevent the foam member from sagging over the wall yet short enough so as to be relatively undetectable by someone sitting on the side of the bed. The inner wall is somewhat shorter than the outer wall to keep material costs to a minimum. The inner wall acts as an anchor to keep the foam members in close proximity to the outer wall. In the case of differing foam thicknesses between the sidewalls and endwalls, the inner wall can be dimensioned accordingly, or an alternative mechanism could be substituted for the innerwall. 
     In use, the mechanism gives the corner of the mattress a crisp appearance, despite repeated usage. The mechanism also assists in keeping bedding, such as fitted sheets, from slipping off of the corners. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the preferred corner piece of the present invention; 
     FIG. 2 is a perspective view of the preferred corner piece of the present invention with a single foam border member inserted therein; 
     FIG. 3 is a perspective partial view of a fluid-filled mattress having two of the preferred corner pieces of the present invention installed thereon; and, 
     FIG. 4 is a perspective view of an alternative embodiment of a preferred corner piece of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1, there is shown the preferred device  10  of the present invention. The device  10  generally comprises a pair of external walls  12  oriented substantially perpendicular to each other. The walls  12  preferably join each other to form a corner  14 . Though the invention could be accomplished without a union to form the corner  14 , joining the walls  12  adds stability and thus allows less material to be used. 
     The walls  12  are also connected to, and held together by, a floor member  16 . The floor member  16  add further stability to the walls  12  and prevents the walls  12  from riding up the sides of the foam borders, which rest upon the floor member  16 . 
     An anchor  18  is provided to keep the device  10  in supporting proximity to the corner formed by the foam borders. Preferably, anchor  18  includes two internal walls  20  extending upwardly from the floor member  16 . The internal walls  20  may gain stability by joining to form a corner  22 . 
     Notably, the external walls  12 , the internal walls  20  and the floor member  16 , together define a channel  24 . Looking also at FIG. 2, it can be seen that the channel  24  is sized to accept the foam borders  26  of the soft-sided mattress. The walls  12  are tall enough to adequately support the foam border  26  yet shorter than the border  26  so that a person will not detect the presence of the device  10  when sitting on the bed. The inner walls  20  are even shorter than the external walls  12 , primarily for purposes of minimizing material costs. 
     FIG. 3 shows the devices  10  maintaining the corners of an assembled soft-sided bed. It can be seen that two borders  26  enter each device  10  and form a butt joint  28  therein. The devices  10  obviate the need for providing covers over the foam borders  26  because fasteners, such as hook and loop fasteners, are no longer needed. It is preferable that each of the devices  10  are formed from a single piece of plastic. 
     Assembly of the foam borders  26  with the devices  10  includes arranging the foam borders  26  in the channel  24  of the device  10  to form a butt joint  28 . The borders  26  are placed on top of the device  10  so that the device  10  is not detected by a person sitting on the bed. The borders  26 , and the devices  10  are covered once four of the devices  10  are installed, one on each corner of the mattress. 
     FIG. 4 shows an alternative embodiment of the corner piece  10  in which the anchor  18  comprises a plurality of spikes  30  extending upwardly from the floor member  16 . The spikes  30  penetrate the foam borders  26  (FIG. 2) thereby preventing relative movement between the corner piece  10  and the foam borders  26 . 
     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. By way of example only, the inner walls  20  of the anchor  18  could be separated such that the corner  22  is not formed. Similarly, the external walls  12  could fail to meet to form the corner  14 . Also, the walls  12  and  20  are shown as substantially rectangular though they could comprise a variety of shapes. The butt joints  28  provide for economic manufacturing. However, if desired, alternative joints, such as miter joints, may be used by shaping the borders differently. 
     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.