The present invention relates generally to concrete wall blocks. More particularly the invention relates to wide or oversized wall blocks having weight bearing pads and to compression head assemblies used during the process of manufacturing the wall blocks from a mold.
Numerous methods and materials exist for the construction of retaining walls and landscaping walls. Such methods include the use of natural stone, poured in place concrete, masonry, and landscape timbers or railroad ties. In recent years, segmental concrete retaining wall units which are dry stacked (i.e., built without the use of mortar) have become a widely accepted product for the construction of retaining walls. Such products have gained popularity because they are mass produced, and thus relatively inexpensive. They are structurally sound, easy and relatively inexpensive to install, and couple the durability of concrete with the attractiveness of various architectural finishes.
It is desirable to build a wall from such blocks quickly and without the need for special skilled labor. The efficiency of building a wall can be measured by determining how fast the front face of a wall is constructed. Clearly, this depends on the size of the blocks used and ease of stacking the blocks.
It is standard practice in the prior art to use similarly sized mold boxes to produce various styles of block. For example, U.S. Patent Application Publication No. 2005/00161106 A1 entitled Method of Making Wall Block, the entirety of which is incorporated herein by reference, describes a standard size mold box of about 18 inches by about 24 inches (about 45.7 cm by about 61 cm), and about 8 inches (20.3 cm) deep. This standard size mold box is used to produce blocks of varying sizes. Since those blocks are typically formed in the mold with their front faces positioned along the 18 inch (45.7 cm) dimension these blocks have a front face with a dimension of 18 inches by 8 inches and a surface area of about one square foot (929 sq cm). The '106 application describes an improvement whereby two blocks are made in a standard size mold box with the front faces of the blocks formed along the 24 inch (61 cm) dimension. Those prior art blocks described in the '106 application are shown in
During the block molding process the mold box is used to form multiple blocks at one time. The mold and a lower plate or production pallet form a cavity for the formation of blocks. Moldable material such as concrete having a composition well known to those of skill in the art is placed into the mold and allowed to set for a time sufficient to allow retention of block shape when the material is removed from the mold box. Often the blocks are formed in the mold box with their lower surface facing up and their upper surface facing down and resting against the pallet. Unless otherwise noted, that is the block orientation which is used in this application. As is well known in the art the material is removed with the aid of a compression head assembly which is lowered from above the mold box and urges the material out of the mold. Once the material is removed from the mold the material in the form and shape of a block or blocks is moved to a curing station where the blocks are allowed to cure while resting on the pallet. Another pallet is positioned under the mold to receive the moldable material which again fills the mold. In this way, many sets of multiple blocks are formed with one mold and many pallets.
During the block molding process it is important that the blocks are made of a uniform and consistent shape and size and that block dimensions, especially block height or thickness, are maintained within acceptable tolerances. This is important for all blocks but especially those made for use in dry stacked walls. There are various ways that the acceptable range of tolerance of block dimensions can be exceeded during the block molding process. Excessive wear or misalignment of the equipment and machinery used in the manufacturing process can result in the production of blocks having one or more dimensions that do not fall within acceptable tolerances. For example, irregularities in height can be the result of the blocks being formed on production pallets which have irregular surfaces. Production pallets can be made of various materials including steel, plastic and wood. Any irregularity in the surface of the production pallet will be imparted to blocks formed on that surface. Although this application focuses on problems caused by the use of fatigued and sagging production pallets it should be understood that the concepts disclosed herein are generally applicable to control tolerances and especially height/thickness tolerances of any wall block caused by any reason.
The size of a typical production pallet used in the block molding process is from 18 inches by 26 inches (46 cm by 66 cm) for the smallest pallet to 44 inches by 55 inches (112 cm by 140 cm). When the pallets are new the surface upon which the blocks are formed and cured is planar and level. The block surface resting against the pallet (typically the top surface of the block) is also planar and level since it assumes the contour of the surface of the pallet upon which it cures. However, older pallets which have been used in many production cycles can begin to sag. A block which is formed and cured on a sagging pallet or on a pallet having an irregular surface for other reasons will assume the contour of the pallet. Thus, the block will be formed with a top surface which is not planar. It is desirable that the dimensions of blocks made during this process are maintained within acceptable tolerances and that surfaces which are meant to be level are, in fact, level. This is especially true of blocks which are made with the intention that they will be dry stacked. In a wall where the blocks are connected with mortar it is possible to correct for misshapen blocks (blocks which do not fall within acceptable tolerances) by using more or less mortar. However, such correction is not possible in a dry stacked wall. If the blocks are small and the walls constructed with the blocks are not too high irregularities in block height created during the molding process may not affect use of the blocks. However, the problem is amplified in larger, wider blocks and blocks used to construct very tall walls. As discussed previously, the size and width of blocks varies depending on the size of the mold and the orientation of the blocks in the mold. For example, the width of blocks may range from less than one foot to two feet.
Accordingly, there is a need in the art to compensate or correct for the dimensional intolerances which are created for various reasons during the block molding and curing process.
The present invention is directed generally at masonry wall blocks having weight bearing pads on an upper or lower surface and to methods of making such blocks. In one embodiment the invention is a wall block having a plurality of weight bearing pads on an upper or lower surface of the block. In another embodiment the invention is a compression head assembly having tamper heads which are used to form weight bearing pads on the upper or lower surface of a wall block during the block molding process. The invention also includes the blocks made with the compression head assembly and walls made from those blocks. The invention also includes a method of constructing a block wall from the blocks made from the compression head assembly. The invention also includes a method of leveling a surface of a block during the block forming process. This method includes measuring the block specifications during the forming process and removing material from a surface of the block or a portion of a surface of a block to level that portion of the surface of the block.
The invention provides a wall block comprising a block body having opposed front and rear faces, opposed first and second side surfaces, and opposed and substantially parallel upper and lower surfaces, at least one weight bearing pad extending from one of the upper and lower surfaces. In one embodiment, the weight bearing pad extends from the lower surface. In an embodiment, the block body comprises two weight bearing pads, and in another embodiment the block body comprises just two weight bearing pads. In an embodiment, the at least one weight bearing pad extends substantially from the rear face to the front face of the block body. In an embodiment, the at least one weight bearing pad is a rectangular prism. In one embodiment, the at least one weight bearing pad has a height of from ⅛ to ½ inch (0.3 to 1.3 cm), and in another embodiment the at least one weight bearing pad has a height of from ⅛ to ⅜ inch (0.3 to 1.0 cm). In an embodiment, the dimensions of the at least one weight bearing pad are from 1 to 3 inches (2.5 to 7.6 cm) wide, 7 to 11 inches (17.8 to 27.9 cm) long, and ⅛ to ⅜ inch (0.3 to 1.0 cm) deep. The at least one weight bearing pad can be level or have a slope.
The invention provides a compression head assembly for use in making wall blocks comprising: a stripper shoe including a bottom portion having at least one opening; and at least one adjustable tamper head sized to be accommodated within the at least one opening in the stripper shoe. In an embodiment, the at least one adjustable tamper head can be raised and lowered relative to the stripper shoe. In an embodiment, the at least one adjustable tamper head can be set at an angle relative to a horizontal plane of the stripper shoe. In one embodiment, the at least one adjustable tamper head can be set at an angle of from 0 to 5 degrees.
The invention provides a compression head assembly for use with a mold in making wall blocks comprising a stripper shoe including a bottom portion for contacting a wall block surface in the mold, the bottom portion having at least one indentation for imparting to the wall block surface at least one raised weight bearing pad.
The invention provides a method of making a plurality of retaining wall blocks comprising providing a mold assembly including a pallet, a compression head assembly, a mold box having at least one mold cavity having an open mold cavity top and an open mold cavity bottom, the mold cavity being shaped to form a single retaining wall block, each retaining wall block having opposed front and rear faces, opposed first and second side surfaces, and opposed and substantially parallel upper and lower surfaces, and at least one weight bearing pad extending from one of the upper and lower surfaces, the compression head assembly comprising a stripper shoe including a bottom portion having at least one opening and at least one adjustable tamper head sized to be accommodated within the at least one opening in the stripper shoe; positioning the pallet beneath the mold box to enclose the mold cavity bottom; filling the mold cavity with dry cast concrete; lowering the compression head assembly to enclose the open mold cavity top and compress the dry cast concrete within the mold cavity, the at least one weight bearing pad being formed adjacent the at least one adjustable tamper head; and lowering the pallet and the compression head assembly to strip the dry cast concrete from the mold cavity.
The invention provides a method of making a plurality of retaining wall blocks comprising providing a mold assembly including a pallet, a compression head assembly, a mold box having at least one mold cavity having an open mold cavity top and an open mold cavity bottom, the mold cavity being shaped to form a single retaining wall block, each retaining wall block having opposed front and rear faces, opposed first and second side surfaces, and opposed and substantially parallel upper and lower surfaces, and at least one weight bearing pad extending from one of the upper and lower surfaces, the compression head assembly comprising a stripper shoe including a bottom portion for contacting a wall block surface in the mold, the bottom portion having at least one indentation for imparting to the wall block surface the at least one raised weight bearing pad; positioning the pallet beneath the mold box to enclose the mold cavity bottom; filling the mold cavity with dry cast concrete; lowering the compression head assembly to enclose the open mold cavity top and compress the dry cast concrete within the mold cavity, the at least one weight bearing pad being formed adjacent the at least one indentation; and lowering the pallet and the compression head assembly to strip the dry cast concrete from the mold cavity.
The invention provides a retaining wall comprising a plurality of courses of retaining wall blocks including a first upper course and a second lower course, each retaining wall block having opposed front and rear faces, opposed first and second side surfaces, and opposed and substantially parallel upper and lower surfaces, and at least one weight bearing pad extending from one of the upper and lower surfaces. In an embodiment, the weight bearing pads in the first upper course and the second lower course are vertically aligned. In one embodiment, the weight bearing pad extends from the lower surface.
The invention provides a method of leveling a wall block comprising providing a wall block comprising a block body having opposed front and rear faces, opposed first and second side surfaces, and opposed and substantially parallel upper and lower surfaces, at least one weight bearing pad extending from one of the upper and lower surfaces; and removing a portion of the at least one weight bearing pad to make the height of the wall block equal to an adjacent block in a course of a retaining wall.
The invention provides a mold box for making first and second wall blocks comprising first and second opposed end rails and first and second opposed side rails, the end rails and side rails together forming a mold box; a divider plate having a first end connected to the first end rail and a second end connected to the second end rail, the divider plate dividing the mold box into a first mold section for forming the first block and a second mold section for forming the second block; and pin hole molding portions attached to the divider plate.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
In this application, “upper” and “lower” refer to the placement of the block in a retaining wall. The lower surface faces down, that is, it is placed such that it faces the ground. In forming a retaining wall, one row of blocks is laid down, forming a course. A second course is laid on top of this by positioning the lower surface of one block on the upper surface of another block.
The blocks of this invention may be made of a rugged, weather resistant material, such as concrete. Other suitable materials include plastic, reinforced fibers, and any other materials suitable for use in molding wall blocks. The surface of the blocks may be smooth or may have a roughened appearance, such as that of natural stone. The blocks are formed in a mold and various textures can be formed on the surface, as is known in the art. Although the embodiments described herein are discussed with reference to a wall block having a front width of 24 inches it should be appreciated that the invention is equally applicable to blocks of all sizes including those whose front faces are either larger or smaller than the ones referenced herein.
As described above due to worn or misaligned equipment used in the block manufacturing process various dimensional intolerances and surface irregularities can be unintentionally imparted to the block. More specifically as described in connection with
The adjustable tamper heads 108 are attached to threaded shafts 110. Shafts 110 are received in apertures in plates 115. Plates 115 are connected between plungers 104. The depth that the tamper heads are received into lower portion 106b is set by adjusting nuts 112 and 114 to raise or lower shafts 110. Each tamper head 108 pivots with respect to shaft 110 at pivot point 116. The angle at which the tamper heads pivot or tilt is adjustable by using set screws 117 and 119 which are threaded into holes in the upper portion 106a of the stripper shoe. By adjusting the depth by which set screws 117 and 119 extend into and through upper portion 106a the angle of the tamper heads 108 can be adjusted in teeter totter fashion.
Since the bottom surfaces of the blocks are oriented upwards in the mold,
Although particular embodiments have been disclosed herein in detail, this has been done for purposes of illustration only, and is not intended to be limiting with respect to the scope of the following appended claims. In particular, it is contemplated by the inventor that various substitutions, alterations, and modifications may be made to the invention without departing from the spirit and scope of the invention as defined by the claims. For instance, the choices of materials or variations in shapes are believed to be a matter of routine for a person of ordinary skill in the art with knowledge of the embodiments disclosed herein. Further, although the invention has been described in connection with blocks having height inconsistencies or intolerances due to forming the blocks on a sagging pallet it should be understood that these inventive concepts and embodiments are also applicable to control height tolerances on any block having height inconsistencies caused by any reason.
This application is a continuation of U.S. Ser. No. 13/759,511, filed Feb. 5, 2013, which is a continuation of U.S. Ser. No. 12/266,951, filed Nov. 7, 2008, which claims the benefit of U.S. Provisional Application No. 60/986,483, filed Nov. 8, 2007, entitled “Wall Block With Weight Bearing Pads and Method of Producing Wall Blocks”, the contents of each of which are hereby incorporated by reference herein.
Number | Date | Country | |
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60986483 | Nov 2007 | US |
Number | Date | Country | |
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Parent | 13759511 | Feb 2013 | US |
Child | 14507295 | US | |
Parent | 12266951 | Nov 2008 | US |
Child | 13759511 | US |