Abstract:
A block splitting assembly and method which uses any of a variety of projections to supplement or replace the action of the splitting blade in splitting and dressing concrete or masonry block. A gripper assembly holds the block during splitting.

Description:
This application is a continuation-in-part of application Ser. No. 09/330,879 filed on Jun. 11, 1999, now U.S. Pat. No. 6,321,740. 

   FIELD OF INVENTION 
   The invention relates generally to manufacture of masonry block. More specifically, it relates to equipment and processes for the creation of decorative faces on masonry block. Even more specifically, the invention relates to equipment and processes for producing roughened textures and the appearance of weathered or rock-like edges on masonry block. 
   BACKGROUND OF THE INVENTION 
   The process of splitting a masonry block to create a rock-like appearance on the exposed face of the block is known. See, for example, Besser, U.S. Pat. No. 1,534,353, which discloses the manual splitting of blocks using a hammer and chisel. Automated equipment to split block is well-known, and generally includes a splitting table comprising a supporting table and one or more hydraulically-actuated splitting blades. These machines are useful for the high-speed processing of blocks. They produce a rock-face finish on the blocks. The edges of the faces are generally well-defined, i.e., “sharp”. 
   It is sometimes desirable to produce a concrete product that has edges which appear to be weathered. This has been a desired look for concrete pavingstones for sometime. Recently, it has become desirable to create the weathered look on the decorative face of concrete retaining wall blocks. The common process for producing the weathered look on pavers is to “tumble” the pavers in a rotary drum to knock off their sharp edges. This process can be used with some retaining wall blocks, as well, provided that the blocks do not have any features, such as integral concrete locator flanges, that would be damaged by the tumbling process. Tumbling is not an option with such blocks. The problem with the tumbling process is that it is costly. The process requires the capital investment in a tumbling apparatus, and the upkeep of that equipment. In addition, the pavers or blocks must be removed from the production line, tumbled, and then reassembled into suitable cubes for transportation. This makes the process labor-intensive. 
   Another option is to use a hammermill to attack the face of the block with various hammers. This option can slow down production, if it is done “in line”, because the process can only move as fast as the hammermill can operate on each block, and the block may need to be manipulated-flipped over and or rotated-to attack all of its edges. 
   Accordingly, there is a need for equipment and a process that will create the appearance of weathered edges on retaining wall blocks, in such a manner that it will not slow down the production line, will not add costly equipment to the line, will not be labor-intensive, and will not have high cull rates when processing blocks with integral locator flanges or other similar features. 
   SUMMARY OF THE INVENTION 
   In accordance with a first aspect of the invention, there is provided a block splitter assembly comprising first and second opposed splitting blade assemblies, each of the first and second splitting blade assemblies comprising respective first and second splitting blades and one or more projections positioned adjacent to each of the first and second blades. 
   In accordance with a second aspect of the invention, there is provided a block splitter comprising first and second opposed splitting blade assemblies, each of the first and second opposed splitting blade assemblies comprising a plurality of projections. 
   In accordance with another aspect of the invention, there is provided a masonry block splitter comprising first and second opposed splitting blade assemblies, the first blade assembly comprising a first splitting blade having first and second sides, said first blade assembly comprising a plurality of projections adjacent the first splitting blade first side and a plurality of projections adjacent the first splitting blade second side, the second blade assembly comprising a second splitting blade having first and second sides, the second blade assembly comprising a plurality of projections adjacent the second splitting blade first side and a plurality of projections adjacent the second splitting blade second side. 
   In accordance with a further aspect of the invention, there is provided a method of splitting masonry block using a masonry block splitter, comprising first and second opposed splitting blade assemblies, said first blade assembly comprising a first splitting blade having first and second sides, said first blade assembly comprising a plurality of projections adjacent said first splitting blade first side and a plurality of projections adjacent said first splitting blade second side, said second blade assembly comprising a second splitting blade having first and second sides, said second blade assembly comprising a plurality of projections adjacent said second splitting blade first side and a plurality of projections adjacent said second splitting blade second side, said method comprising the step of striking the masonry block with said first and second opposed splitting blade assemblies. 
   In another aspect of the invention, a gripper assembly is employed to hold the work piece together from the sides during splitting. The gripper assembly could optionally include side knives or projections. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a partial perspective view of a block splitting machine using the block splitter blade assembly of the invention. 
       FIG. 2A  is a top plan view of one portion of a splitting blade assembly in accordance with the invention. 
       FIG. 2B  is a top plan view of one portion of a splitting blade assembly also showing projections of various diameters positioned in a random manner. 
       FIG. 2C  is a top plan view of one portion of a splitting blade assembly in accordance with a further alternative embodiment of the invention comprising projections which are random connected and unconnected panels. 
       FIG. 3  is a side elevational view of an alternative embodiment of a projection in accordance with the invention. 
       FIG. 4A  is a side elevational view of a further alternative embodiment of a projection in accordance with the invention. 
       FIG. 4B  is a side elevational view of another alternative embodiment of the invention depicting projections of varying height. 
       FIG. 5  is a perspective view of a split work piece (forming two masonry blocks), which was split using the splitter blade assembly of the invention. 
       FIG. 6  is a top plan view of a masonry block split using the splitter blade assembly of the invention. 
       FIG. 7  is a front elevational view of the masonry block depicted in FIG.  6 . 
       FIG. 8  is a partial sectional end view of an alternative embodiment of a top splitter blade assembly. 
       FIG. 9  is a partial sectional end view of an alternative embodiment of a bottom splitter blade assembly. 
       FIG. 10  is a top plan view of a portion of the  FIG. 9  embodiment of a bottom splitter blade assembly shown in relation to a work piece. 
       FIG. 11  is a top plan view of a gripper assembly according to the present invention, and another alternative embodiment of a bottom splitter blade assembly, shown in relation to a work piece. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Attention is now directed to the figures where like parts are identified with like numerals through several views. In  FIG. 1 , a conventional block splitting machine modified in accordance with invention is depicted, in part, showing in particular the block splitter assembly  10 . Generally, block splitting machines may be obtained from Lithibar Co., located in Holland, Mich. In particular, the Lithibar Co. 6386 was used in practicing the invention. The block splitter assembly generally has opposed first  12  and second  22  splitting blade assemblies. The first splitting blade assembly  12  is positioned at the bottom of the block splitter  10  and, as depicted, includes a splitting blade  14  and a number of projections  16  positioned on either side of and adjacent to the blade. 
   The invention may be used with any variety of blocks molded or formed through any variety of processes including those blocks and processes disclosed in U.S. Pat. No. 5,827,015 issued Oct. 27, 1998, U.S. Pat. No. 5,017,049 issued May 21, 1991 and U.S. Pat. No. 5,709,062 issued Jan. 20, 1998. 
   An upper or second splitting blade assembly  22  may also be seen in FIG.  1 . The second splitting blade assembly  22  also includes a splitting blade  24  and a plurality of projections  26  located on either side of the blade  24 . The second splitting blade assembly may be attached to the machine&#39;s top plate  30  through a blade holder  28 . The position of the work piece  40 , (shown in phantom), within the block splitter may be seen in  FIG. 1 , in the ready-to-split position. 
   As can be seen in  FIG. 2A , the splitting blade assembly  12  is generally comprised of a number of projections  16  positioned adjacent to blade  14  and on either side of the blade  14 . As shown, the projections  16  on the first side of the blade are staggered in relationship to the projections  16 ′ on the second side of the blade. The projections on either side of the blade may also be aligned depending upon the intent of the operator. 
   As can be seen in  FIG. 2B , the projections  16  may be used without a splitting blade. The projections  16  may also be varied in diameter or perimeter, (if not round), and placed randomly on the splitting assembly  12 . Any number of ordered or random patterns of projections  16  may be created using regular or irregular spacing depending on the effect to be created in the split block. 
     FIG. 2C  shows a further alternative embodiment of the invention where plates  16 ″ are attached to either, or both, assemblies  12  and  22 . As can be seen, these plates may be configured in random order and left unconnected across the surface of the assembly  12 . The invention has been practiced using steel plates about four inches long welded to the assembly to provide a number of partially connected projections  16 ″ about two inches high. As shown in  FIGS. 1 ,  2 A, and  2 B, the projections  16  and  16 ′ may have a rounded shape. However, the shape of the projections may also be pyramidal, cubic, or pointed with one or more points on the top surface of the projection. In  FIGS. 2B and 2C , the relative position of the work piece  40  is again shown in phantom outline. 
   Generally, the projections may have a diameter of about ½ to 1 and ¼ inches and may be attached by welding, screwing or other suitable means. The height of the projections may be about 1 and ¼ inches and varied about ¾ of an inch shorter or taller depending upon the affect to be created in the block at splitting. Attaching the projections by threading or screwing, see  FIGS. 8 ,  9  and  11 , allows easy adjustment of projection height. 
   The relative height of the projection and blade may also be varied depending upon the effect that is to be created in the block split according to the invention. Specifically, as can be seen in  FIG. 3 , the relative height of the blade  14  may be less than the relative height of the projection  16 . Alternatively, as can be seen in  FIG. 4A  the relative height of the blade may be greater than the height of the projections  26 . For example, we have found with the first splitting blade assembly  12  that X may range from about ⅛ to about ⅜ of an inch beyond the first blade. With regard to the second splitting blade assembly  22 , X′ may range from about {fraction (1/16)} to ⅛ of an inch beyond the height of the plurality of the projections. 
   Projections  16  such as those depicted in  FIG. 2A  have been found useful having a diameter of about 1 and ¼ inches and, when used with a blade  14 , having a height of about ⅛ of an inch above the blade in the first or lower assembly and ⅛ of an inch below the blade in the second or upper assembly. Overall, the height of the projections may vary up or down about ⅜ of an inch relative to the height of the blade. 
   In operation, the work piece is generally centered in the block splitter according to known practices as seen in  FIGS. 1 ,  2 A,  2 B and  2 C. The block splitter is then activated resulting in the first and second opposing splitting blade assemblies converging on, and striking, the work piece  40 . In operation, the first and second splitting blade assemblies may travel anywhere from about ¼ to one inch into the top and bottom surfaces of the work piece. The work piece  40  is then split resulting in an uneven patterning on the split edges  46   a ,  46   b  and  46   a′ ,  46   b′  of the resulting blocks,  44  and  42 , as illustrated in FIG.  5 . As depicted, the work piece  40 ′ is split in two. However, it is possible and within the scope of the invention to split the work piece into more than two pieces. 
   The distance traveled by the projections  16  into the work piece may be varied by adjusting the limit switches on the machine and, in turn, varying the hydraulic pressure with which the splitting assembly acts. Generally, the splitting assemblies act on the block with a pressure ranging from about 600 to 1000 psi, and preferably about 750 to 800 psi. 
   As will be well understood by one of skill in the art, the splitting machine may include opposed hydraulically activated side knife assemblies (not shown) which impinge upon the block with the same timing and in the same manner as the opposed top and bottom assemblies. Projections  16  may also be used to supplement or replace the action of the side knives. For example, side knives similar to the upper splitting blade  24  shown in  FIG. 8  can be employed. 
   Closer examination of block  44  after splitting (see  FIGS. 6 and 7 ) shows the formation of exaggerated points of erosion in the front, split surface  47  of the block  44 . With the block  44  depicted, both the first and second blade assemblies  12  and  22  comprised projections  16  and  26 , respectively. As a result, depressions  48  and  50  were formed at the upper and lower edges  46   a ,  46   b  of the front, split surface  47  of the block  44 , at the intersection of the upper  52  and lower  54  respective surface of the block  44 . 
   The magnitude of the indentations,  48  and  50 , or points of erosion is far greater than that which is caused by conventional splitting blades and may be varied by varying the prominence of the projections  16  and  26 , (height and size), relative to the height and thickness of the blade. In one embodiment of the invention, masonry block may be split with only a row or rows of projections  16  and  26  without a blade  14  and  24 . 
   Referring to  FIGS. 8 and 9 , alternative embodiments of a top splitting blade assembly  22 ′ and bottom splitting blade assembly  12 ′, respectively, are shown. It has been found that more massive blades  14 ′,  24 ′ having projections  16 ,  26  thereon create a more desirable block face appearance. Blades  14 ′,  24 ′ each include a central cutting edge  21  and  31 , respectively, and surfaces  19 ,  29  extending outwardly therefrom. Surfaces  19 ,  29  are at a blunt angle so as to make the top and bottom edges of the block face more rounded and therefore rock-like. The surfaces  19 ,  29  are preferably at an angle β between 0° and 30° relative to horizontal, most preferably 23°. 
   Blades  14 ′,  24 ′ include projections  16 ,  26  that are adjustable and removable. In this way, the same blade assembly can be used for splitting different block configurations by changing the number, location, spacing and height of the projections. Projections  16 ,  26  are preferably threaded into corresponding threaded openings  17 ,  27  for adjustment, although other height adjustment means could be employed. The top surface of projections  16 ,  26  is jagged, comprising many pyramids in a checkerboard pattern. Projections such as these can be obtained from Fairlane Products Co. It will be understood that a variety of other projection top surface configurations could be employed. 
   The height of the top surface of projections is preferably a distance X′ below the top of cutting edge  21 ,  31 , most preferably 0.040 inch below. As discussed above with respect to other embodiments, the projections may extend further below, or some distance above, the top of the blade, within the principles of the invention. The projections shown are ¾ inch diameter with a 10 thread/inch pitch, and are 1.50 inches long. Diameters between 0.50 and 1.0 inch are believed preferable. The loose block material from the splitting process entering the threads, in combination with the vertical force of the splitting strikes, are considered sufficient to lock the projections in place. 
   The preferred top blade assembly  22 ′ is 2.5 inches wide. Projections  26  extend perpendicularly from blade surfaces  29  and therefore strike the working piece at an angle. 
   The preferred bottom blade assembly  12 ′ is 4.0 inches wide. Projections  16  extend upwardly from shoulders  23  on opposite sides of blade surfaces  19 . This configuration breaks away more material and creates a more rounded rock-like top edge (the work piece is typically inverted) of the split blocks. Blade assembly  12 ′ could optionally include projections  16  on blade surfaces  19 , as shown in FIG.  11 . 
   In operation, the blade assemblies of  FIGS. 8 and 9  are used together and in the same manner described above with respect to cutting depth and hydraulic pressures. It will be understood that the bottom blade assembly could be used on top, and the top blade assembly could be used on the bottom. 
   Referring now to  FIG. 10 , a blade assembly  12 ′ according to  FIG. 9  is depicted positioned for striking a work piece  40 . Work piece  40  comprises portions which will result in small  60 , medium  62  and large  64  blocks. A projection  16  is preferably placed at each comer of the three blocks  60 ,  62 ,  64  to be created, as shown. In this way, more rounded, rock-like comers are formed in the splitting process. This positioning of projections at the block comers can be used in conjunction with mold configurations that pre-form the slab at the comers so as to better achieve this effect. Upper blade assembly  22 ′ of  FIG. 8  has similarly oriented projections except that they are closer to a centerline of the workpiece, as can be seen from FIG.  8 . 
   Referring now to  FIG. 11 , a gripper assembly  70  is shown in conjunction with a work piece  40  and bottom splitting blade assembly  12 ′. Gripper assembly  70  is employed to assist with splitting certain types of larger block units. It is mounted via mounting head  71  on the existing side-knife cylinders of the splitting machine. Rubber shoes  72  are configured to conform to the corresponding outer surface of work piece  40 . Each gripper assembly  70  moves in and out laterally, as indicated by arrows, in order to grip work piece  40  from both sides. In the preferred design, assembly  70  is 3.0 inches high and rubber shoes  72  are 50-100 Durometer hardness. The pressure applied by the hydraulic cylinders is the same as that for the upper and lower blades. 
   One benefit of this gripper assembly is improving the formation of rounded edges of a work piece made by a bottom blade. Work piece  40  is moved along the manufacturing line by positioning bar  80  in the direction of the arrow shown. During splitting, while the rear portion of work piece  40  is held in place by bar  80 , the forward portion is free to move forwardly. Many splitting machines have a splitting action whereby the bottom blade moves to engage the product after the top blade has touched the top of the product. The initial cutting action of the top blade can begin to move the forward portion forwardly before the bottom blade has an opportunity to fully form a rounded edge on the forward block with, for example, projections  16  and/or blade surfaces  19 . The bottom blade assembly can also lift the work piece, which is undesirable for a number of reasons. By holding the work piece  40  together during splitting, these problems are prevented. 
   Gripper assembly  70  can optionally include projections  16 , as shown in FIG.  11 . Projections  16  are preferably positioned slightly inside the top and bottom edges of the work piece (four projections for each gripper assembly  70 ) so when they strike the side of the work piece  40 , more rounded block corners will be formed. The assembly can also include a side knife contained within its central cavity  73 , having a blunt blade such as those described hereinabove, for forming rounded, rock-like side edges of the split blocks. It may be necessary to include an appropriate strength spring behind the side knife in order to get the desired action from the gripper and knife. 
   The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.