Abstract:
An inflatable building block is provided with collapsible sides. Coupling means on the upper and lower faces allow the blocks to be interconnected to form structures. A preferred format relies on pleated sides that will collapse in an accordion-like fashion.

Description:
This application is a continuation-in-part of application Ser. No. 07/977,859, filed 17 Nov., 1992. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to building materials and particularly stackable blocks. More specifically, the invention includes designs for building blocks which may be collapsed for storage. Such blocks are particularly suited as toys for children, but industrial applications exist for the invention as well. 
     BACKGROUND OF THE INVENTION 
     Building blocks which are hollow have been disclosed previously. An example is described in the U.S. Pat. No. 5,035,098 to Newsom. In the Newsom patent, molded containers for liquids are made in a shape which allows them to be assembled in a nested fashion to form a wall. It is contemplated that these containers be used to construct wall-forms after they have served as containers to transport fluids, and have been emptied. The Newsome containers are described throughout as being rigid and are not collapsible in any way. 
     A reference that has issued for a collapsible building element is U.S. Pat. No. 2,990,837 to Cushman. This document describes an air inflated wall structure that may be erected to form a large circular enclosure. Periodically placed internal panels, placed transversely within side walls, constrain the shape of the inflated structure to form the walls of the enclosure. A bottom tube is filled with water in order to provide ballast for the structure. 
     Other inflated structures are described in the following references: 
     U.S. Pat. No. 3,432,609 to Duvall 
     U.S. Pat. No. 4,556,391 to Tardivel et al 
     U.S. Pat. No. 5,236,261 to Wilbourn et al 
     None of these references, however, describe a stackable building block which may be inflated to form a stable structure. It is with the objective of providing such a product that this invention has been conceived. 
     The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation. The invention in its broadest and more specific forms will then be further described, and defined, in each of the individual claims which conclude this Specification. 
     SUMMARY OF THE INVENTION 
     In its more general sense the invention comprises a hollow, air-tight, modular, stackable building block for constructing a structure having corrugated or pleating sides which will collapse, and a sealable orifice whereby a fluid filling such as water, air or free-flowing sand may be introduced into and out of the interior cavity formed within the modular building block in order to maintain its shape. 
     The top and bottom faces of the block are preferably made relatively rigid, as compared to the sides. Such faces are preferably generally horizontally oriented and are provided with complementary connector or coupling means, such as protrusions and depressions formed on the respective top and bottom faces, whereby the blocks can be laid in interfitted courses to form a more stable structure. Ideally, the protrusions and depressions are positioned so that the blocks may be staggered to increase their interlocking strength. Additionally, the protrusions and depressions are preferably positioned to permit construction of walls having corners, and angular deflections from the shape of a simple plane structure. This may include both fixed 90 degree deflections and a range of other deflections extending upwards from zero degrees. 
     The sides of the block are intended to be collapsible. They may be formed from thin-walled, pleated sheeting. In the pleated format the blocks may be collapsed and expanded in an accordion-like manner. 
     A preferred manner for fabricating the blocks of the invention is by blow-molding. However, other known suitable fabrication means may alternately be employed. 
     The foregoing summarizes the principal features of the invention and some of its optional aspects. The invention may be further understood by the description of the preferred embodiments, in conjunction with the drawings, which now follow. 
    
    
     SUMMARY OF THE FIGURES 
     In drawings which illustrate the embodiments of the invention: 
     FIG. 1 is a perspective view of an embodiment of the invention with pleated side faces. 
     FIG. 2 is a cut-away end view of the pleated embodiment of FIG. 1 in fully erect, inflated form. 
     FIG. 3 is a partial end view of the pleated side wall of the block of FIG. 2, with the block partially collapsed. 
     FIG. 4 is a perspective view of the bottom of a cross-sectioned block as in FIGS. 1-3. 
     FIG. 5 is a detailed cross-section of the receptacle depressions formed in the bottom of the block of FIG. 4. 
     FIG. 6 is a face view of the block of FIG. 1 showing four coupling posts positioned on the top of the block. 
     FIG. 7 is a top view of FIG. 6. 
     FIG. 8 is a bottom view of the block of FIGS. 1 and 7. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 shows a perspective view of a block with pleated accordion-like sides. The block 50 has relatively flat top 51 and bottom 52 faces with outwardly directed exterior surfaces in the form of panels which are sufficiently thick to be relatively stiff. The encircling sides 53 delimiting the boundaries of the top 51 and bottom 52 faces have end 54 and face portions 55 which are pleated in an accordion-like manner to permit folding and compression of the sides 53, and thereby to provide for the collapse of the block, as shown in FIG. 3. 
     This block 50 is preferably blow-molded from polyethylene or polypropylene plastic, with a side-wall thickness on the order of 1 millimetre and preferably a thickness of 1-3 mm in the top 51 and bottom 52 panels. Inset ribs 56 may optionally traverse the top 51 and/or bottom 52 panels to increase stiffness. Further stiffening may be provided by additional ribs. 
     Preferred dimensions for the block are 24 to 30 cm long by 12 to 15 cm wide and by 12 to 15 cm high. However, the size of the blocks is not restricted to any specific specifications, and may be changed according to the purpose. The same applies in relation to the shape of the block, and the blocks can be made in the shape of half-blocks or trapezoidal shapes. 
     Protrusions 57 extend upwardly from the top panel 51 and are intended to inter-engage in sockets 65 in the bottom panel 52 and serve as attachment or coupling means. A preferred configuration for the protrusions 57 is to have a single row, centered on the longitudinal middle or median line 59 within the longitudinal median plane of the block 50 and symmetrically disposed about the transverse middle or median line 58 within the transverse median plane of the block 50. 
     Top and bottom faces 6, 8 may each contain two complimenatry VELCRO (TM) -type pads 14 as a means to attach completed blocks together to form a stacked structure. 
     In FIG. 2 a profile end view of the block 50 shows that the protrusion 57 may have a tapered upper edge or shoulder 60 and a lip 61 to assist in assembly and in providing positive attachment. 
     In FIGS. 4 and 5 the lower panel 52 with its complementary sockets 65 is depicted. The sockets 65 each have a tapered socket shoulder 63 over which the ends 62 of the protrusions 57 may slide as an alignment guide during assembly. Grooves 64 at the perimeter of the socket shoulder 63 engage the lips 61. These grooves 64 are shown as being provided with a circular rim 72. This rim 72 may be interrupted to form a series of protruding lugs 73 shown in one example in FIG. 8. Such lugs 73 will expand and release more readily than a continuous rim. 
     A sealable orifice in the form of valve well 66 is provided with a preferably self-closing valve 67 at its end, although a manually sealable orifice may also be employed. This valve may be opened, as by a pencil or finger, to allow air or other flowable substance to enter or escape from the block. 
     As shown in FIGS. 2 and 6 (only), the sides 53 of the block 50 are optionally provided with notches 68 along the perimeter of the bottom panel 52 to receive fingers during separation and disassembly of the blocks. These, as shown in FIGS. 4 and 6, may be positioned opposite sockets 65. The ribs 56, in the form of a depressed groove, as shown in FIG. 1, preferably extend to the outer edge of the block 50 where they can be seen. By locating the ribs 56 at regularly spaced intervals, their outer ends serve as alignment guides for fitting the protrusions 57 into the receptacles 65. 
     The sockets 65 may be laid-out in a multiple, overlapping cross-format, best seen in FIG. 8. This pattern of sockets 65 allows the blocks to be oriented at 90 degrees, if two sockets 65a, 65b are engaged by protrusions 57; or to swing over a range of degrees if a end socket 65c only is engaged by a single end protrusion 57. This range of motion is limited by interference between the first unengaged protrusion 57a and the top face 51. This allows for more complex structures to be formed than that of a simple, planar wall. 
     While the blocks of FIG. 2 and 6 are intended to be stacked to form a wall structure having staggered, inter-engaged, over-lying courses with the pleated sides 93 forming the vertical sides, such blocks may also be stacked with the pleated sides 53 forming the top and bottom faces of the block. 
     Blocks according to the invention are suited to be stacked up by children to construct larger toy play structures than traditional sized blocks, optionally large enough to walk-into. They may also be used to create functional structures that benefit from the insulating qualities of air-filled blocks. Blocks of the invention may also be filled with water, sand or other flowing materials for such applications as flood or military use. 
     The blocks enjoy the advantage of being light and compact to store and transport. If made of polymer plastic, they are generally weather-proof. A further advantage is that when produced on a mass basis, such blocks should be relatively inexpensive. 
     Conclusion 
     The foregoing has constituted a description of specific embodiments showing how the invention may be applied and put into use. These embodiments are only exemplary. The invention in its broadest, and more specific aspects is further described and defined in the claims which now follow. 
     These claims and the language used therein, are to be understood in terms of the variants of the invention which have been described. They are not to be restricted to such variants, but are to be read as covering the full scope of the invention as is implicit within the invention and the disclosure that has been provided herein.