Abstract:
An apparatus and method for roughing surfaces of concrete casted blocks are provided. A horizontally disposed surface roughing device, having impacting elements secured thereto, is driven to impact on blocks supported thereunder on a support table. The support table has a flat support upper surface. Block tilt support pins project from the upper surface at predetermined locations for supporting some of the blocks tilted at a predetermined angle. The block tilt support pins are displaceable from a retracted position below the upper surface to a projecting block tilting position above the upper surface. A displacement mechanism imparts translationary displacement between the impacting elements and the support table to abrade the blocks.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to casted concrete block manufacturing and, more particularly, to an apparatus for roughing blocks to give them a worn or rough appearance.  
         BACKGROUND OF THE INVENTION  
         [0002]    The concrete block casting industry is well developed and is highly automated in its process operations for manufacturing conventional rectangular blocks and the like. The casted blocks have a geometrically uniform rectangular prism configuration in which the surfaces thereof are substantially planar with adjacent surfaces delimited by sharp edges.  
           [0003]    It has been known to treat the concrete blocks in order to get a more natural rough look. As antique stone blocks were known to have rounded edges and irregular shaped surfaces, systems have been provided in order to produce such effect on the concrete blocks. However, the equipment used in order to treat these blocks has been incompatible with the fully automated handling equipment used in the other operations of the concrete block producing process. Substantial amount of manual labor and high costs are inherent with the presently used block roughing systems.  
           [0004]    For instance, a known method consists in disposing the casted blocks in large tumbling drums. These tumbling drums are rotated about their longitudinal axis in order for the concrete blocks to tumble therein and to collide in order to get damaged. This method, although producing a generally satisfying look, entails substantial costs due to unrepairable damages to concrete blocks. Some blocks are damaged to a point where they may no longer be used and are thus thrown away or recycled. Also, some concrete block patterns may contain blocks of different sizes and these must be stored, which is very time consuming. Also, if a particular one of the blocks in pattern is destroyed more than other blocks, then often the other blocks are no longer useful as a ratio of blocks must be kept. By its nature, the tumbling drum requires frequent repairs. Furthermore, the personnel used for these purposes must deal with a noisy environment due to the tumbling action, and injuries are frequent due to the hazardous operations and handling required thereby. It is difficult to maintain a stable labour force for this work.  
           [0005]    U.S. Pat. No. 5,133,915, issued on Jul. 28, 1992 to Metten et al., discloses a surface upon which a plurality of concrete blocks are disposed in a spaced apart relationship. A roller brush translates over the surface of concrete blocks in a reciprocating manner, thereby stripping and roughing the surface of the concrete blocks. Although this method provides substantial advantages over the tumbling drum method described above, it requires that the concrete blocks are spaced apart in order for the sharp edges thereof to be treated. Otherwise, only the top surface would be abraded. Furthermore, the brush type roller provides a relatively uniform abrasion of the concrete blocks, which is not a desired result for use with paving blocks. Finally, as the concrete blocks are spaced apart, the brush can only strike them at a certain velocity in order not to displace them. If they are displaced, they may end up in abutment with one another, whereby only the top surfaces will be abraded, leaving the sharp edges of the block intact. These blocks are usually treated before concrete is cured.  
         SUMMARY OF THE INVENTION  
         [0006]    It is a feature of the present invention to provide a concrete block roughing apparatus which substantially overcomes the disadvantages of the above mentioned prior art.  
           [0007]    According to the above features, from a broad aspect, the present invention provides an apparatus for roughing surfaces of concrete casted blocks. The apparatus comprises a horizontally disposed surface roughing device having a plurality of impacting elements secured thereto and driven to impact on a plurality of the blocks supported thereunder on a support table. The support table has a flat support upper surface, block tilt support means is projectable from the upper surface at predetermined locations for supporting at least some of the plurality of the blocks tilted at a predetermined angle. Means is also provided to displace the block tilt support means from a retracted position below the upper surface to a projecting block tilting position above the upper surface, and displacement means to impart translationary displacement between the impacting elements and the support table to abrade the blocks.  
           [0008]    According to a further broad aspect of the present invention, there is provided a method of roughing surfaces of concrete casted blocks comprising the steps of (i) placing a plurality of the blocks on a flat top surface of a support table and at a predetermined orientation in side-by-side and end-to-end relationship; (ii) tilting predetermined ones of the blocks on the support table to expose predetermined portions of the blocks; (iii) axially rotating a horizontally disposed surface roughing device having a plurality of impacting elements secured thereto; and (iv) causing relative displacement between the surface roughing device and the support table to roughen exposed surfaces of the blocks by said impacting elements striking exposed areas of said blocks. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    A preferred embodiment of the present invention as illustrated by examples thereof will now be described with reference to the accompanying drawings in which:  
         [0010]    [0010]FIG. 1 is a fragmented side elevational and partly sectioned view of an apparatus for roughing concrete blocks in accordance with the present invention;  
         [0011]    [0011]FIG. 2 is a perspective view, partly fragmented, of the apparatus for roughing concrete blocks;  
         [0012]    [0012]FIG. 3 is a perspective view, partly fragmented, of tilting mechanisms in accordance with the present invention;  
         [0013]    [0013]FIG. 4 is a perspective view, partly fragmented, of a tilting mechanism according to another embodiment of the present invention;  
         [0014]    [0014]FIG. 5 is a perspective view, partly fragmented, showing a still further embodiment of the present invention;  
         [0015]    [0015]FIG. 6 is a perspective view, partly fragmented of the roughing tool; and  
         [0016]    [0016]FIG. 7 is a perspective view, partly fragmented, of another embodiment of the roughing tool. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0017]    According to the drawings and more particularly to FIG. 1, there is shown an impact rotor roughing tool R and a block tilting table T constructed in accordance with the present invention. Referring now to FIG. 2, the block tilting table T is shown having a generally rectangular shape with a top surface  10  and a bottom surface  11  delimited by side edge surfaces  13 , and with concrete blocks C disposed thereon. A plurality of throughbores  12  are equidistantly spaced on the top surface  10 , which is substantially planar in order for the concrete blocks to be slid into position thereon. It is observed that the throughbores  12  are spaced in straight parallel columns and provided such that each concrete block C disposed on the table spans over at least two throughbores  12 . For instance, each concrete block C, as shown in FIG. 2, may overlap two throughbores  12 .  
         [0018]    Abutment flanges  14  are disposed over two opposed side edge surfaces  13  of the top surface  10 . The abutment flanges  14  are held at free ends of cylinders  14   a , such as to be displaceable toward the table T, to secure the concrete blocks C disposed thereon. It is pointed out that although cylinders are illustrated in FIG. 2, whether actuated electrically, pneumatically or hydraulically, pistons or the like could also be used for the above described purpose. The abutment flanges  14  ensure that concrete blocks C transferred to the top surface  10  by any automated mechanism will be aligned with respect to the throughbores  12  by abutting thereagainst. The flanges  14  are not in tight contact with the blocks C, thereby allowing the blocks C to be tilted. Furthermore, the flanges  14  are sized not to interfere vertically with the roughing tool R.  
         [0019]    Referring now to FIG. 1, the block tilting table T is shown having pins, namely  20   a ,  20   b ,  20   c  and  20   d  amongst others, in each of the throughbores  12 . The pins  20  each have a cam follower portion  21  disposed at a lower distal end thereof. Helical tension springs  22  are shown secured to the bottom surface  11  of the table T and exert a pressure on the cam follower portion  21  of the pin  20 , to bias the pins  20  downward with respect to the block tilting table T. When one of the helical springs  22  is extended, the pin (as shown by pin  20   b ) is in a retracted position, whereas when one of the helical springs  22  is contracted, the pin (as shown by pin  20   a ) is in a projecting block tilting position. In the retracted position, the pin is completely below the top surface  10  of the table T, whereas, in the projecting block tilting position, the pin extends upward from the top surface  10  to tilt a concrete block C, as shown in FIG. 1.  
         [0020]    In order to actuate the pins between the retracted position and the projecting block tilting position, tilting mechanisms are provided and are generally shown at  15   a ,  15   b ,  15   c  and  15   d  in FIGS. 1 and 3. For reference purposes, sets of corresponding X and Y axes have been provided and will be referred to hereinafter. Each of the tilting mechanisms is constructed similarly. Thus, the tilting mechanism  15   a  will be described and like numerals will designate like elements thereafter.  
         [0021]    As best seen in FIG. 3, the tilting mechanism  15 A comprises a shaft  16 A having a plurality of cams  17 A equidistantly spaced thereon. The cams  17 A are displaceably secured to the shaft  16 A, and are thus positioned so as to each be under one of the throughbore  12 .  
         [0022]    Referring now to FIGS. 1 and 3, the cams  17  are shown having a pair of pin retracted surfaces  18  and a pair of pin extended surfaces  19 . The cam follower portions  21  of the pins  20  are in constant operative contact with the cams  17 . When the cam follower is in contact with one of the pin retracted surfaces, as shown by cam follower  21   b  and cam  17   b , the pin is in the retracted position. On the other hand, when the cam follower is abutting one of the pin extended surfaces, as shown by cam follower  21   a  and cam  17   a , the pin is in the projecting block tilting position.  
         [0023]    When the blocks are disposed on the top surface  10  of the table T, each pin  20  is in the retracted position. Thereafter, alternate tilting mechanisms  15   a  and  15   c  are actuated in concert by an indexing motor, schematically shown at M in FIG. 2, in order to extend upward to the projecting block tilting position, thereby tilting the concrete blocks C disposed on the top surface  10  of the block tilting table T, as depicted in FIG. 1. Consequently, the sharp edges of the concrete blocks are exposed to the roughing tool R. It is observed that the other set of alternating tilting mechanisms,  15   b  and  15   d  are actuated thereafter by another indexing motor M in order to expose the other sharp edges of the concrete blocks C while the tilting mechanisms  15   a  and  15   c  are actuated back to their retracted position. Referring now to FIGS. 4 and 5, alternative embodiments of the present invention are shown whereby the pins  20  are actuated by pneumatic or electrical members.  
         [0024]    Returning to FIG. 1, the roughing tool R is generally shown having a cylindrical body R upon which are secured chains  30 . As seen with greater detail in FIG. 6, the roughing tool R is comprised of support bars  31  removably connected between a pair of bar attachment disks, one of which is shown at  32 . A drive shaft  33  is secured to the disk  32 , whereas the other disk  32 ′ is connected to an idle and free to rotate shaft  33 ′. A plurality of chain link sections  30  are secured to the support bars  31 , and are comprised of at least two interconnected loop chain links. The support bars  31  extend through an end loop of each chain link sections  30 . By rotating the roughing tool R on its longitudinal axis, the chain link sections  30  will impact on the concrete blocks disposed on the table T. The roughing tool R, although illustrated as translating in the Y axis direction, may translate in both the X axis and Y axis direction or at an angle therebetween by displacing mechanism  50 . In the Y axis direction, the roughing tool R translates to strike successive rows of concrete blocks C each having a sharp edge exposed as explained above. Once the roughing tool R reaches an end of the table T, it may translate backwards in order to strike the opposing edges of the concrete blocks which have been lifted to be exposed, in which case the roughing tool R rotates in an opposed direction by being driven by a reciprocating gear coupling G and motor, as shown schematically in FIG. 2.  
         [0025]    It has also been thought to provide guides and drive mechanisms for displacing the table T instead of the roughing tool R, as shown at  60  in FIG. 7. In such a case, the table T could be rotatable in order for the chain link sections  30  of the roughing tool R to strike the concrete blocks C disposed on a table at an angle.  
         [0026]    It is pointed out that the concrete blocks C may be positioned on the tilting table T such as to overlap a pair of throughbores  12  on their width. For instance, the concrete blocks illustrated in FIG. 2 may be transferred after being treated thereon to another table which will expose their longitudinal edges, whereby all four edges of a top surface of the concrete blocks will be roughened. Also, varying patterns of concrete blocks may be disposed on the tilting table T at a same time.  
         [0027]    The roughing tool R may be actuated according to a predetermined velocity of rotation. Consequently, various levels of intensity may be provided to the roughing tool R, whereby various levels of abrasion as achieved on the concrete blocks C to chip or scratch the blocks. The tool R may also reciprocate as it rotates. The simplicity of the above described invention allows for a substantial saving in the labor used in order to execute the maneuvers required by the methods of the prior art. It is readily understood how the use of the above described invention may be fully automated. Furthermore, the resulting abrasion on the concrete blocks is relatively consistent according to the intensity of the roughing tool R. However, the movement of the chains  30  of the roughing tool R is not controlled and thus random patterns of abrasion are provided on the concrete blocks C. The above described system is space efficient as the concrete blocks C are disposed in an optimal manner. The only element of the above described invention subject to impacts are the chains  30 , whereby the repair maintenance costs remain low relatively to the prior art. It is pointed out that the chains  30  are of a material harder than the concrete blocks C, which may be bricks, paving stones, retaining wall blocks or masonry stones. The production output is continuous as the timing and intensity of the operation may be controlled.  
         [0028]    It is within the ambit of the present invention to cover any obvious modifications of the embodiments described herein, provided such modifications fall within the scope of the appended claims.