Patent Application
20060180731
This invention relates generally to a liner for holding objects in place within a form for a poured wall so that the objects are embedded on the surface of the wall once the form and the liner are removed. More particularly, the present invention relates to a new and improved foam liner mounted to a backing material to form a continuous liner sheet that facilitates lining the form for the poured wall.
Modern building construction commonly includes simulated brick or stone walls to reduce the costs associated with fully laid up brick and stone walls. Such simulated walls are typically formed by embedding thin bricks or stones within a front surface of a poured concrete wall. For example, thin bricks or pavers are typically arranged on a front surface of a wall form prior to filling the form with a concrete slurry. Once the concrete slurry cures and the form is removed, the front face of the wall includes the brick pavers and, when done correctly, gives the impression of a true brick wall such as would be constructed by a mason.
Liners are typically used to both arrange and hold the brick pavers within the form for the poured wall. The liners include a number of recessed regions separated by joints for holding the brick pavers in a desired pattern. The joints between the recessed regions of the liner essentially form a reverse contour for the concrete slurry which fills in the spaces between the bricks and forms a “grout line” between the sides and ends of adjacent bricks. This grout line is similar to that which is present in conventional masonry construction.
A number of different types of brick liners have been utilized in the past. These include vacuum formed liners which are typically molded from a hard plastic material as well as foam liners that are molded or routed from a solid piece of foam to define the desired brick pattern. However, both of these types of liners suffer from problems that add to the cost and time required to form embedded brick walls with these prior art liners.
With respect to prior plastic liners, such liners are typically formed in relatively small sheets or “panels,” such as the VersaLiner™ panel manufactured by Innovative Brick Systems, Inc. of Broomfield, Colo. The size of these prior art brick liner panels is necessarily limited due to manufacturing and handling constraints (i.e., each panel holds approximately 40 bricks). Accordingly, a number of the liner panels must be aligned both vertically and horizontally within the form for the poured wall to provide an aesthetically acceptable simulated brick wall.
Each plastic liner panel includes outer borders shaped like the joint lines which extend between the bricks on the liner. These borders must be precisely aligned and overlapped with the borders on adjacent panels to provide a seamless continuation from one liner panel to the next and thereby maintain the illusion of the simulated brick wall. However, cutting and aligning a large number of hard plastic liner panels to fit within a form is time-consuming work. Furthermore, due to the inherent thickness of each plastic liner panel, the regions within the form where two or more panels overlap are necessarily raised above the remainder of the liners within the form so that the embedded bricks (or other objects) along these overlapping regions may appear to be misaligned or slightly recessed within the finished wall.
A further difficulty encountered with the prior plastic liner panels relates to the rigid nature of the panel material and particularly the curved joints between the recessed brick-receiving regions. These hard plastic joints define uniform brick-receiving regions in the liner panel which, in turn, require the use of brick pavers that are cut to very precise tolerances (so that the edges of the brick pavers fit snugly against the rounded plastic joints). Indeed, a close fit between the brick pavers and the plastic joints is necessary to prevent or at least reduce the amount of concrete material that leaks around the plastic liner joints and adheres to the face of the brick pavers. Unfortunately, such leakage is bound to occur since even custom-ground brick pavers will include some tolerance or margin of error in their outer dimensions. While brick pavers that are cut too small will leave a gap between the brick and at least one joint line that allows the poured-wall material to seep past the joint and contact the face of the brick paver, problems also arise when brick pavers are cut too large to fit cleanly within the brick-receiving region. Specifically, because the hard plastic joint lines are not malleable, the joints cannot adjust to accommodate oversized bricks. Thus, even a slightly oversized brick paver (i.e., ⅛ inch or more out of specification in either the length or the height dimension) will not be seated correctly within the liner, thereby allowing the poured-wall material to leak around to the front of the brick paver. Additionally, oversized bricks that do not fit properly within the liner will be misaligned (i.e., will not appear flush) with the other bricks, possibly causing unacceptable visual defects in the finished wall.
In order to ensure that the finished brick wall may be cleaned of any concrete material that collects on the front faces of the bricks, it is typically necessary to use specialized brick pavers that have had their faces coated with wax. Upon completion of the formed wall and removal of the plastic liner panels, a hot water (high pressure) spray is then applied to the face of the brick wall to remove the wax coating and any accumulated concrete material. In order to ensure that the wax can be removed with the hot water spray, the wax coating has a melting point of approximately 130 degrees Fahrenheit. However, in certain climates (such as Florida or Arizona), the temperatures in the mold may rise close to or even exceed the melting point of the wax, thus causing the wax coating to soften and wick into the brick or simply evaporate. A further drawback to the use of a wax coating relates to the added cost to have each brick coated with wax. Indeed, the combined extra cost of first grinding the brick pavers to the exacting dimensions required for use within the hard plastic liner, and then applying a wax coating to the faces of the brick pavers, nearly doubles the price of a standard brick paver.
Thus, prior art plastic brick liners suffer from a number of drawbacks mainly centering around the rigid nature of the plastic joints used to define the brick-receiving regions within the liner. Since it is not possible to form an airtight seal between the brick paver and the plastic joint lines (even when using ground bricks), concrete leakage onto the front faces of the brick pavers will be a constant problem necessitating the use of specialty wax-coated bricks to ease the process of cleaning the concrete off of the finished brick faces. Additionally, the plastic liner panels are not thermally stable, and thus the same high temperatures that can create difficulties with the wax coating may also cause the liner material itself to expand and create even larger gaps between the joints and the brick pavers. Lastly, workers using rigid plastic liner panels are not able to adjust the size or location of the vertical head joints to accommodate wall forms that are not sized to precisely fit the dimensions of the plastic liner panels (or to accommodate changes in the size of the panels due to temperature changes). For example, when a half-brick offset or “running bond” pattern is to be formed in a poured wall, it is desirable for the pattern to terminate precisely at the end of the wall so that only conventional full brick and half-brick pavers are required at each end of the wall. Unfortunately, due to measurement errors and the above-described thermal instability of the plastic liners, it is common that the one-half running bond brick pattern will not fit precisely within the wall form, thereby necessitating the grinding of custom-sized bricks (e.g, ⅜ and ⅞ bricks) to complete the pattern at one end of the wall. While a mason forming a fully laid-up brick wall can address such issues by adjusting (i.e., increasing or decreasing) the width of the vertical head joints near the end of the wall to ensure a proper fit, no such adjustments are possible with the fixed vertical head joints in the plastic liner panels.
While prior art foam liners address some of the above-described problems attributed to the hard plastic liner panels, such foam liners were not without their own problems. In particular, prior art foam liners used for casting objects in a poured wall were die cut or routed from a solid piece of foam to define the desired brick pattern. The foam grid was then placed on a paper backing with pressure sensitive tape as shown in U.S. Pat. No. 5,900,180 (“the '180 patent”). The '180 patent shares a common inventor with the currently-claimed invention, and the disclosure of the '180 patent is hereby incorporated by reference.
A second problem associated with the foam liner shown in the '180 patent relates to the act of cutting or routing the foam material to form the desired grid pattern as shown in
Finally, while the malleable nature of the foam liner disclosed in the '180 patent helps to form a relatively snug seal with the brick pavers (thereby reducing the amount of leakage and accumulation of concrete on the faces of the bricks), the fully integrated nature of the foam grid (as shown in
Thus, a new brick liner is needed that addresses the shortcomings of both the prior art foam brick liners as well as the plastic liner panels. Specifically, a need exists for a brick liner which creates a more natural (i.e., curved) grout line in the finished wall but which does not require the use of specially prepared (i.e., ground and waxed) brick pavers. A need also exists for a brick liner that includes flexible head joints to allow for slight adjustments to the running bond pattern at one end of a form to avoid the need for custom-sized bricks at the end of a wall. Finally, a need exists for a foam liner that can be quickly and easily employed at the job site and then stripped completely from the finished wall.
It is with respect to these and other background considerations, limitations and problems, that the present invention has evolved.
In accordance with this invention, the above problems are solved by a liner for casting objects in a face of a poured wall. The liner is positioned within a form for the poured wall and acts to hold the objects stationary (in a desired pattern) when a slurry of concrete or some similar material is poured into the form and covers the liner. The liner is formed from a backing sheet and a plurality of foam bed joints that extend in a substantially parallel fashion along a length dimension of the backing sheet. A plurality of separate foam head joints are also attached along a height dimension of the backing sheet, wherein opposing ends of the foam head joints engage adjacent bed joints to define a plurality of regions on the backing sheet for receiving the objects to be cast in the poured wall.
In one embodiment, each of the foam bed joints and foam head joints have a substantially semi-circular cross section with a flat base portion attached to the backing sheet and a rounded upper portion adapted to form a rounded grout line between the objects cast in the poured wall. The foam joints also include an outer protective skin to prevent the poured wall material from bonding with the foam cells. Two or more liner sheets may be combined to cover an extended wall surface by providing a finished edge and an open edge at opposite ends of the liner.
In a further embodiment of the present invention, the backing sheet is made from paper and may include either a plastic liner or a mesh sheet to increase the tear-resistance of the paper backing sheet. An adhesive layer may be applied to a top surface of the paper backing sheet to secure the foam joints in a desired running bond pattern. Furthermore, the individual head joints are separately detachable from the backing sheet to enable customized sizing for each of the object-receiving regions within the liner.
A further embodiment of the present invention relates to a method of forming a liner for embedding a plurality of objects in a face of a poured wall. The method includes adhering a plurality of extruded foam bed joints to a top surface of a backing sheet and also adhering a plurality of separate foam head joints to the top surface of the backing sheet between adjacent bed joints. The plurality of bed joints and separate head joints combine to form a plurality of regions for receiving the objects to be embedded within the poured wall. In one embodiment, the top surface of a backing sheet is coated with an adhesive layer and is then pressed into contact with a grid formed by the separate bed joints and head joints.
A more complete appreciation of the present invention and its scope may be obtained from the accompanying drawings, which are briefly summarized below, from the following detailed description of a presently preferred embodiment of the invention, and from the appended claims.
The liner sheet 20 is shown in greater detail in
The head joints 44 extend vertically along a height dimension “H” of the liner sheet 20, and while the embodiment shown in
The plastic liner 54 is included between the opposing paper sheets 50 and 52 as a waterproofing measure to help protect the paper sheets and prevent water from soaking the entire backing sheet 40 (a distinct possibility considering that the liner sheets 20 will be used at construction sites). Additionally, the nylon mesh sheet 56 is preferably included within the quad-ply construction to promote tear resistance, particularly in the event that one or both of the paper sheets 50 and 52 do become wet. While a nylon mesh is shown in
A preferred construction of the bed joints 42 is illustrated in
A further benefit attributed to the foam joints 42 and 44 of the present invention is that the outer skin 62 is textured in comparison to prior art hard plastic liners, and thus the corresponding grout lines in the finished wall are provided with a more natural “sand” finish as opposed to the smooth grout lines produced by prior art plastic liners. Indeed, the curved, sand-finished foam joints 42 and 44 of the present invention produce highly realistic grout lines in the finished wall that are difficult to distinguish from typical masonry construction.
The present invention also improves over prior art foam and plastic liners by providing increased flexibility for receiving oversized bricks 22, as illustrated in
The compressibility of the joints 42 and 44 provides an important benefit over prior plastic liners that were relatively rigid and offered only a limited ability to properly seat an oversized brick paver within the brick receiving region 46. Furthermore, while prior art foam liners provided a slightly higher degree of flexibility to accommodate oversized bricks, the integrated construction of the prior art foam liners (i.e., a grid cut from a solid foam piece) created difficulties for workers attempting to seat the oversized bricks since the square foam joints offered no “rolling” ability and tended to bind at the corners where the bed joints and head joints met. Indeed, as described in the Background section above, prior art foam liners had a tendency to push oversized bricks back out of the brick receiving pocket 46 since forcing one oversized brick into its associated pocket placed increase pressure on all of the adjacent pockets due to the unified construction of the prior foam grids. However, this problem is greatly reduced by the liner sheets 20 of the present invention due to the fact that each of the bed joints 42 and head joints 44 are separately attached to the backing sheet 40. This separate construction is shown in
Thus, the use of separate bed joints 42 and head joints 44 (i.e., adhering the joints separately to the backing sheet 40 but not to each other) provides a number of benefits over the prior art foam liners that were cut from a single foam piece. While some of these benefits relate to manufacturing cost and ease of use of the finished product (as described below), one important benefit includes an enhanced ability of the joints 42 and 44 to flex and move in response to oversized brick pavers 22. For example, if a brick paver 22 is slightly oversized in its length dimension, at least one end of the paver 22 will tend to compress or roll a head joint 44 to make room for the oversized brick. Because the head joint 44 is not attached to the two adjacent bed joints 42 (as in the prior art), a worker filling the liner 20 with bricks will not meet any significant resistance as the head joint 44 is compressed, nor will the insertion of the oversized brick 22 adversely affect or dislodge any of the pavers 22 positioned above or below the oversized brick 22 in the liner 20. While an adjacent brick receiving pocket 46 may be reduced in size due to the rolling motion of the head joint 44, this discrepancy can be accommodated by slightly compressing the next head joint 44 in the row. Similarly, if a brick paver 22 is oversized in its height dimension (as illustrated in
Furthermore, while the head joints 44 are precisely mounted on the adhesive backing material 40 to define equally-spaced brick receiving regions 46 (using a below-described preferred process), the separate nature of the head joints 44 makes it is possible for workers to slightly alter the position of the joints 44 in order to accommodate a wall form 26 (
As described above, the liner sheet 20 is preferably formed on a continuous roll of the backing sheet 40 so that prescribed lengths of the liner sheet 20 may be shipped to a job site and unrolled in a form 26 (
The conveyor belt 90 preferably includes a segmented track 92 made up of a plurality of individual links 94 that together define a series of horizontal bed joint grooves 96 that extend between adjacent rows of the links 94, as well as a series of vertical head joint grooves 98 that extend between adjacent columns of the links.
Once the bed joints 42 and head joints 44 have been properly positioned in the grooves 96 and 98, the conveyor belt track 92 is preferably fed beneath a heated roller 100 together with the adhesive backed sheet 40 as shown in
In both the embodiments shown in
In summary, the foam brick liner 20 of the present invention is easier to use and provides a more uniform finished wall surface than the prior plastic and foam brick liners described above. Significantly, in light of the ability of the separate foam joints 42 and 44 to accommodate slightly oversized bricks 22, the foam liner 20 may be used with standard brick pavers 22 (as opposed to specialized and costly pavers that have been ground to precise specifications). Furthermore, the foam joints 42 and 44 are separately extruded with a curved or domed shape to closely mimic the grout lines formed by masons, but unlike prior plastic liners providing a similar shape, the malleable foam joints 42 and 44 provide a gasket seal with the bricks 22 to reduce or essentially eliminate concrete seepage to the front face of the brick pavers. Indeed, due to the snug fit provided by the foam joints 42 and 44, the wax coating that must be applied to the bricks used with the prior art plastic liners is no longer needed, thereby further reducing the costs associated use of the foam liner 20. As described in U.S. Pat. No. 5,900,180 (incorporated by reference above), sugar may be used in lieu of wax to retard the curing action of the cement on the front face of the brick pavers 22. Thus, in lieu of applying wax to each brick paver 22 (a costly procedure as described above), a sugar coating may be applied to the liner sheet 20 following the application of the foam joints 42 and 44 to the adhesive backing sheet 40. Specifically, sugar may be used to coat the brick receiving regions 46 on the liner sheet 20 prior to placing the brick pavers 22 within the regions 46. Thus, upon completion of the wall 24 and removal of the liner sheet 20, the sugar coating preferably acts to inhibit the hardening of any concrete material that may have seeped past the foam joints to the front faces of the brick pavers. Specifically, any seepage that may have occurred during the pouring process is easily cleaned from the untreated brick faces by the use of a pressure sprayer or some alternative cleaning process due to the retarding action of the sugar.
Thus, unlike the prior plastic liner sheets described above, the foam liner 20 of the present invention may be used with conventional brick pavers 22 (thereby providing a cost savings over those pavers that require precision grinding and a wax coating). Additionally, the foam liner 20 provides numerous benefits over prior foam liners that were formed from a single foam sheet. Namely, the extruded foam joints 42 and 44 do not bond with the concrete material and thus the foam liner 20 may be easily stripped from the finished wall, as described above. Furthermore, the separate (non-integrated) nature of the bed joints 42 and the head joints 44 provides great flexibility in placement of the head joints, particularly on the job site where slight modification of the head joint location may be required to meet the dimensions of a particular wall form. The foam joints 42 and 44 are also better able to accommodate oversized brick pavers than the prior foam liners where any strain on a single foam joint would be transferred to all the neighboring joints. Lastly, the foam liner 20 may be formed in long, continuous rolls due to the separate application of the extruded bed joints 42 and head joints 44. These rolls may be cut to a precise length as required for a specific job site, or they may simply be cut to length to match the form at the construction site. Thus, while the foam liner 20 includes various finished and open edges to allow for the stacking of multiple sheets 20 (as described above with respect to
While a number of presently preferred embodiments of the present invention have been described with a degree of particularity, this description of preferred examples is not intended to limit the scope of the invention. For example, the present invention is not limited to the use of brick pavers 22 as shown in the drawings. Rather, the shape of the “brick” receiving regions 46 could be altered to hold tile, stone or some other common embedded object in place of the brick pavers 22. The scope of the invention is thus defined by the following claims.
