Abstract:
The method of this invention concerns bonding side-to-side glass or plastic building blocks to obtain decorative and/or functional modular sub-assemblies, walls, panels, floors, windows, skylights, etc., using flexible, light-weight, elongated, adhesive tape strips to adhesively bond together at least portions of complementary block side surfaces to construct multi-tier building block units.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The technical field primarily concerns permanently bonding side-to-side glass or plastic building blocks to obtain decorative and/or functional modular sub-assemblies, walls, panels, floors, windows, skylights, etc. 
     2. Description of the Known Prior Art 
     The conventional methods for bonding such building blocks employ bonding compositions, such as mortar, cement, grout, caulking and/or silicone. At least for commercial applications, mortar still remains the prevailing bonding medium. Optionally, a silicone or grout sealant is typically applied over each mortar joint to seal it against mold or mildew. 
     As judged architecturally, aesthetically and structurally, the quality of such glass block units depends to a large extent on the uniform alignment of the mortar joints within a common row and between successive rows in horizontal and vertical directions. Such uniform joint alignments depend, among other things, on the volume of mortar the installer spreads on and around each glass block. 
     Since the mortar volume is generally “eye-balled”, obtaining consistent joint alignments becomes a challenge even for the expert artisan. Do-it-yourselfers fear joint misalignments which might make their finished glass block panels or walls structurally and aesthetically unreliable. Such joint uniformity is necessary within a completed glass block unit to make it structurally sound and pleasing in appearance. 
     Also, the use of mortar adds considerable weight to a glass block assembly and reduces the construction speed since only a limited amount of mortar can be mixed, as the mortar&#39;s curing time controls the speed of assembly and finish. The number of courses of blocks that can be laid up at a time is also reduced due to the concern that the excessive weight of the freshly laid up blocks in the upper rows may squeeze the mortar out from the fresh mortar joints in the lower rows. 
     It is evident, therefore, that the known mortar methods for assembling glass/plastic blocks require skilled artisans to properly align their completed mortar joints, and to maintain the joints&#39; width uniform during the whole installation leading to a completed building block unit. 
     Also, such known mortar methods can create serious health hazards from prolonged exposure to conventional bonding and sealing materials: mortar, cement, grout, caulking and/or silicone. They tend to generate dust and release chemical gases, all of which in accumulation can produce lasting injuries to block laying artisans and others on the worksite. As a consequence, builders were discouraged from extensively using glass and/or plastic blocks except for relatively expensive custom homes and overhead applications such as skylights. 
     To obviate some of such adverse effects, many patents suggest using separate rigid interlocked spacers for aid in forming grid-like structures intended to surround and maintain the individual glass or plastic blocks. 
     In particular, U.S. Pat. No. 5,430,985 describes longitudinal spacers  10  for enclosing the center ridges  76  that extend peripherally around and between the lateral faces of the glass blocks. Each spacer  10  has opposite longitudinal center sections. Each section has a rectangular, longitudinally-extending groove  42  dimensioned to receive an opposite glass block center ridge  76 . Fasteners  50  mechanically interconnect adjacently positioned spacers  10 . Pressure-sensitive, adhesive-coated foam bands  44  are used for aligning grooves  42  relative to their opposite block center ridges  76 . Abutting glass blocks  72 , spacers  10 , and fasteners  50  are permanently bonded to one another using mortar or silicone compositions. 
     It is a main object of this invention to use light-weight, action-activatable adhesive tapes to adhesively bond building blocks and to provide a relatively fast, easy, clean, and economical method for producing single or multi-tier building block units, wherein each block remains strongly bonded side-to-side to its abutting blocks, and wherein the inter-block joints have a uniform width dimension determined mostly by the thickness of the used adhesive tapes. 
     It is another object of this invention to overcome the above mentioned and other undesirable effects associated with the prior art mortar and mortarless methods for bonding building blocks, generally, and in particular for bonding blocks made of glass or plastic. 
     SUMMARY OF THE INVENTION 
     The method of this invention relates to bonding building blocks, each having a pair of opposite spaced-apart lateral faces and side faces therebetween, to create multi-tier building block units. Flexible, light-weight, elongated, adhesive tape strips, whose potency is responsive to a sufficient pressure force, bond the adhesive tape strips to at least portions of complementary side surfaces, thereby creating inter-block tape joints. The applied pressure force is maintained for a time needed to activate the curing of the adhesive within the inter-block joints. Preferably, the building blocks are made of a glass or other suitable material. 
     A multi-tier building block unit made in accordance with this invention includes a plurality of building blocks, each having a pair of opposite spaced-apart lateral faces and side faces therebetween. Adhesive tape strips bond portions of each block&#39;s complementary side surfaces so as to form inter-block tape joints, each having a width corresponding to the thickness of the tape strips, and each tape strip serves as the sole bond within its joint. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features believed to characterize the invention are set forth in the appended claims. The invention itself, however, as well as other features and advantages thereof, will be best understood by reference to the detailed description which follows, read in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a top view of a roll of pressure sensitive tape; 
     FIGS. 2A-2G are front views of various shapes of common building blocks; 
     FIG. 3 is a perspective view of an untaped square block shown in FIG. 2E; 
     FIGS. 4A-4H illustrate the steps used to fully tape up the square block shown in FIG. 2E; 
     FIG. 5 is an end view of the fully taped up square block shown in FIG. 3; 
     FIG. 6 illustrates the on site construction of a double-tape-joint, three course window unit using the square taped up blocks shown in FIG. 5; 
     FIG. 7 is an exploded view of the blocks within the double-tape-joint window unit shown in FIG. 6; and 
     FIG. 8 illustrates the on site construction of a single-tape-joint, three course window unit using the square blocks shown in FIG.  2 E. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     In the drawings, to facilitate the description, the same or similar parts, functioning in the same or similar manner, are designated with the same numerals. 
     The following description deals primarily with the most common generally rectangular or square building blocks  10  (FIGS. 2E,  3 ). With appropriate modifications the description applies equally to less commonly used building block shapes: octagonal (FIG.  2 A), rectangular (FIG.  2 B), hexagonal (FIG.  2 C), triangular (FIG.  2 D), circular (FIG. 2F) and pentagonal (FIG.  2 G). The blocks  10  can be made of glass or plastic or other materials used for constructing finished building block units  11 . 
     Each square block  10  (FIGS. 3,  5 ,  8 ) has a pair of opposite, square or rectangular, parallel, spaced-apart, lateral faces  12  and four side faces  14  therebetween. An outwardly-extending, circumferential center ridge  16  extends peripherally around and midway between the block&#39;s lateral faces  12 . 
     Each peripheral edge of each lateral face  12  includes an outwardly-projecting rim  20 : four rims  20  for a rectangular or square lateral face  12 , and three rims  20  for a triangular lateral face  12 . Each rim  20  exhibits a substantially flat exterior rim surface or face  18  lying in a plane substantially perpendicular to the planes of the block&#39;s lateral faces  12 . 
     Although many types of adhesive tapes, generally designated as  22  (FIG.  1 ), may be employed, it has been found that pressure-activatable or pressure-sensitive adhesive tapes have sufficient strength and are most effective for carrying out the objects of this invention. 
     Presently preferred pressure-activatable adhesive tapes  22  are commercially available from the Minnesota Mining &amp; Manufacturing Co. (3M) of St. Paul Minn. as well as others, in rolls or sheets in different colors, width and thickness, under the trade names “Scotch Brand” Acrylic Foam Tapes having designations “4945”, “4946” and “VHF-4950”. 
     It is believed that the pressure-activatable adhesive consists of an acrylic copolymer matrix and of glass microbubbles dispersed throughout the matrix, and that such or similar pressure-activatable adhesive tapes are described in U.S. Pat. No. 4,223,067, assigned to 3M. (It should be understood, however, that this invention is not limited to any particular type of adhesive tape nor to a particular action for activating the tape.) Preferably, the tape strips&#39; adhesive is pressure-activatable and tacky at room temperature. 
     For modular constructions it is convenient and economical to first “tape-up-blocks” in a shop remote from the actual construction site. Such techniques lend themselves to mass-production. Prepared taped-up blocks can be transported to a remote construction site for assembly into a desired wall, window, shower or other building unit  11  (FIGS.  6 , 8 ). 
     For such modular purposes, appropriately sized flexible, light-weight, elongated, pressure-activatable, individual, adhesive tape strips  24  (FIGS. 4A-4H) are precut or die-cut from sheets or from rolls  9  (FIG. 1) of adhesive tapes  22  to correspond to the dimensional requirements of rim faces  18 . 
     Each prepared tape strip  24  (FIGS. 4A-4H) has a tacky adhesive interior skin  26  and an exterior skin  26 ′ that is covered by a paper release liner  28  (FIG. 1) to protect the skin  26 ′ from dust and other contaminants. 
     A strip&#39;s width dimension is selected to fit the width of its corresponding rim faces  18 . Its thickness is selected to correspond to the desired width of its block joint  30  or  31  (FIGS.  6 - 8 ). Each joint  30  contains a pair of back-to-back tape strips  24 , while each joint  31  contains a single tape strip  24  so that the tape strips are substantially entirely confined inside the tape joints. The length of each strip  24  is selected to correspond to the length of rim faces  18  extending from the block&#39;s lateral faces  12 . 
     The bonding of an adhesive skin  26  to a rim face  18  involves two steps: 
     (a) briefly and properly applying an initial sufficient pressure force represented by a horizontal vector force H (FIGS. 4D,  6 ) or by a vertical vector force V applied perpendicularly to the pressure-activatable skin  26  to initiate its curing and adhesion to rim face  18 , and 
     (b) maintaining the applied pressure for a relatively short time period in order to allow the curing to create a permanent bond between the skin and the rim face. 
     The bond strength will correspond to the strength and performance of the adhesive matrix. When an adhesive skin  26  is activated, under a briefly applied pressure stress, it softens and still remains fairly elastic and tacky so that, during a block assembly, strip  24  will temporarily hold a block  10  in its desired position and will conform and adhere to the rim&#39;s face  18  and to any irregularities therein. 
     After a relatively short time interval, the adhesive&#39;s elasticity decreases sharply until it reaches its desired cured or thermoset state, resulting in a complete optimum adhesive bond between the abutting adhesive skin  26 ′ and a rim face  18  of an adjacent abutting block, or in a bond to a rough sill, frame, or other base foundation  13  (FIGS. 6,  8 ), or to an abutting adhesive skin  26 ′. 
     The above adhesive bonding steps (a) and (b) are repeated as many times as needed to create all modular adhesive double-tape block joints  30  or single-tape block joints  31  required for erecting a single or multi-tier unit  11 . 
     It will be appreciated that this adhesive curing process is relatively fast (compared to cement curing) even under varying temperature, humidity and low-to-high pressure environments. 
     The adhesive tape strips  24  serve as the sole bonding means for adhesively inter-connecting abutting rim faces  18  of block side faces  14  and forming therewith adhesive inter-block joints  30 ,  31  whose width substantially corresponds to the thickness of the cured adhesive strips  24 , and whose strength corresponds to the strength and performance of the adhesive&#39;s matrix. 
     Obviously, before adhesive skins  26  and  26 ′ can be adhesively bonded to one another, or to rim faces  18 , or to a rough sill, frame, or other base foundation  13  (FIGS. 6,  8 ), their protective paper liners  28  need to be peeled off to expose their underlying adhesive skins  26 ′. Obviously also, this can be accomplished at a remote workshop as well as on a job site whichever is most convenient. 
     In a single-tape construction, taping-up a rim face  18  involves bonding to the rim face the interior skin  26  of a single adhesive tape strip  24  FIG. ( 4 ) using the two step method, i.e., briefly and properly applying a sufficient initial pressure force to the interior skin  26  perpendicular to the plane of the rim face  18  to initiate adhesion to the rim face, and maintaining the applied pressure for a relatively short time period in order to allow curing to create a permanent bond between the interior skin  26  and the rim face  18 . The exterior skin  26 ′ of the tape strip  24  remains covered by its protective cover  28 . 
     Modular construction of single-tape building units  11  at the shop site can be achieved by first bonding the interior skins  26  of single tape strips  24  to alternate rim faces  18  of each block  10 . 
     Construction of a prefabricated unit  11  (FIG. 8) begins by disposing two taped-up blocks  10  side-by-side so as to maintain narrow gaps between their untaped rim faces  18  and their opposite taped rim faces. Then the exterior skin  26 ′ of each tape strip  24  is bonded to its opposite untaped rim face  18  so as to create a single-tape block joint  31 . Then other taped-up blocks are added and then bonded in a similar manner until the first “course”, (FIG. 6A) or row of unit  11  reaches the desired length and width dimensions. 
     The adhesive bonding process of an exterior skin  26 ′ is initiated by briefly and properly exerting on the taped-up block a sufficient pressure force, in the direction in which adhesion is required, that is perpendicular to the plane containing the rim face  18 , and maintaining the applied pressure for a relatively short time period in order to allow curing to create a permanent bond between the exterior skin  26 ′ and the untaped rim face  18 . 
     Until partial curing is reached, each of the blocks can be slightly adjusted to accommodate proper alignment, that is, to allow each block proper placement with respect to its adjoining blocks. 
     After laying the first course of blocks (FIG.  6 A), a second course of blocks (FIG. 6B) is set up side-to-side, and each subsequent course (FIG. 6C) thereabove, by repeating the steps used to construct the first course, until the desired unit  11  is completed and the single-tape block joints  31  (FIG. 8) are aligned in all directions. 
     Vertical alignment of the single-tape joints  31  is achieved by matching the alignments of the blocks in the first course (FIG. 6A) and making the necessary adjustments prior to applying the physical forces to the blocks to initiate and complete adhesive curing. However, the pressure forces must now be applied in horizontal and vertical directions, represented in the drawings by vector forces H and V, respectively, perpendicularly to the rim faces  18  within unit  11 , so as to initiate and complete the adhesive curing within joints  31 . 
     Modular construction of double-taped units  11  can be achieved in a very similar manner but by bonding the interior skins  26  of single tape strips  24  to all rim faces  18  of each block instead of to alternate rim faces  18  as was done during the construction of a single-tape unit  11 . 
     Construction of a prefabricated unit  11  begins by disposing two taped-up blocks  10  side-by-side (FIG. 6) so as to maintain narrow gaps between their taped rim faces  18 . 
     Then the exterior skin  26 ′ of each tape strip  24  is bonded to its opposite exterior skin  26 ′ so as to create double-tape block joints  30  (FIG.  7 ). Similarly taped-up blocks are added and then bonded in a similar manner until the first (FIG. 6A) course or row of unit  11  reaches the desired length and width dimensions. 
     After laying the first course of blocks, a second course of blocks (FIG. 6B) is set up side-to-side, and each subsequent course (FIG. 6C) thereabove, by repeating the steps used to construct the first course, until the desired unit  11  is completed and the double tape block joints  30  are aligned in all directions. 
     FIGS. 6,  7  and  8  show examples of a practical, pre-fabricated glass block window unit  11  which has been installed in conventional rough openings and which can be finished using conventional trim elements. 
     Constructing a building-block unit on site begins by making sure that the rough sill, frame, or other base foundation  13  is level, plumb, and designed to bear the weight of the completed unit  11 . 
     The first course (FIG.  6 A), or row of prepared taped-up blocks  10  is bonded directly to the rough sill, frame or other base foundation  13 , as well as to adjacent taped-up blocks  10 . 
     The first taped-up block of unit  11  is laid by applying an appropriate pressure force H in the horizontal plane to initiate and complete the adhesive bonding process of the adhesive skins  26  to the rough sill, frame, or other base foundation  13 . 
     Subsequent prepared taped-up blocks are then bonded to adjacent blocks as well as to the rough sill, frame, or other base foundation  13  as above described. 
     The first course (FIG. 6A) being level, sets the horizontal alignment and establishes the foundation for the alignment of each additional course. Subsequent courses (FIGS. 6A-6C) are added, using the first course as a rough sill and template. 
     As judged architecturally, aesthetically and structurally, the quality of block units  10  depends to a large extent on the uniform alignment of their building block joints  30  or  31  within a common row, as well as between successive rows in horizontal and vertical directions. 
     The desirable effects and architectural advantages, associated with the mortarless, relatively light-weight glass and plastic block units  11 , should now encourage builders to more extensively use glass and plastic blocks  10 . 
     It will be appreciated that since the tape strips  24  are generally of uniform thickness, consistent alignment of joints  30 ,  31  in all directions within a completed glass block unit  11  can be readily achieved. 
     Using the process of this invention, it now becomes economical for do-it-yourselfers to construct glass or plastic block units  11  of uniform appearance and save on expensive labor costs, especially for overhead applications such as skylights which are best suited for adhesively-bonded, relatively light-weight plastic blocks. 
     The adhesive tape strips  24  increase the speed of laying up units  11 , decrease the time required to properly adjust and align the blocks&#39; adhesive joints  30 ,  31  as they are being assembled in stacked rows. 
     The number of courses of blocks that can be laid up at a time is increased, due to the lack of concern that the excessive weight of the freshly laid up blocks in the upper rows might squeeze out the tape strips from the joints in the lower rows, as is the case when mortar is used. 
     Also, since no mortar is being used by the process of this invention, no health hazards are expected from prolonged exposure to installations using adhesive tape strips  24 , thus improving on the safety in the work environment and decreasing insurance liability costs. 
     Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. The scope of the invention is defined in the claims appended hereto.