Abstract:
A machine for dressing externally viewable surfaces of a building block. The machine includes transport section and a block modifying section. The transport section engages a building block and the block modifying section dresses the viewable surfaces of the block. The transport section and the block modifying section are moved in a linear direction, relative to each other. The block modifying section is able to dress an entire viewable surface of a block or selected portions of a block. The block modifying section includes block modifier units that have different operational characteristics and motions. One block modifier unit operates in a reciprocating fashion and another block modifier unit operates in a rotary fashion. The different block modifier units are used on different viewable surfaces of a block and may be used alone or in conjunction with each other to produce building blocks having differently dressed viewable surfaces.

Description:
BACKGROUND  
       [0001]    This application relates generally to machines used to fabricate building blocks. More particularly, this application relates to a machine for dressing externally viewable surfaces of blocks used to construct retaining walls, free-standing walls, paved surfaces, and the like. 
         [0002]    Building blocks are widely used in a variety of applications, and can be used to retain soil, as fences, as structural components of buildings, as sidewalk surfaces, and as road surfaces. A particular style of building block that is increasing in popularity is the rustic or weathered look. Rustic or weathered look blocks are desirable for several reasons. They convey the impression of craftsmanship that is nowadays frequently absent. They convey a sense of security and stability. And, they are visually pleasing to an observer. 
         [0003]    A variety of approaches have been used to create rustic appearing blocks. The most elementary and straightforward approach is to take a molded block and hand dress or roughen the surface using hammer and chisel. Another approach has been to provide a patterned mold that is able to simulate a rustic surface. Unfortunately, while it eliminates the step of hand dressing, a user is more-or-less stuck with the product as it comes from the mold. Any modification thereafter would defeat the purpose of such a block. Another approach is to take a molded block and place it in a rotatable container that tumbles it about (preferably, with other blocks or suitable material). The problem with this approach is that as a block is being tumbled, all of the exterior surfaces, including critical locater protrusions and mating surfaces, are being ground down. If the protrusions are knocked off or damaged during the tumbling process, the ability to interlock and/or provide proper spacing is compromised. Another approach attempts to form rustic surfaces by splitting a block into smaller segments along a predetermined plane. This creates two blocks, each with a front face that has the appearance of a natural split rock. While attractive, the split surfaces do not convey the impression that they were hand worked. Yet another approach uses flails to modify the externally viewable surfaces of blocks. Typically, the flails comprise short sections of chain one end of which is affixed about the perimeter of a rotatable shaft, the other end of which may be provided with an enlarged head of steel or other similar material. In operation, the flail ends (with the enlarged heads as the case may be) strike the entire front surface of a block as they are swung about by the rotatable shaft. 
       SUMMARY  
       [0004]    In one embodiment, a machine works externally viewable surfaces of building blocks so that they appear to have been hand dressed. For purposes of this application, the term block (or masonry block) is intended to include any naturally occurring material, manmade material, molded cementitious block, natural and artificial stone or like material that may be used for buildings, indoor walls, partitions, facades, retaining walls, walkways, freestanding walls or fences, capstones, pavers, or other similar structures, with or without the use of mortar or its functional equivalents. 
         [0005]    In a preferred embodiment, the machine comprises a main frame, a transport section, and a block modifying section. The main frame is constructed and arranged to support the transport section, which comprises a movable support portion and a stabilizer portion. The movable support portion includes an upper surface upon which one or more blocks may be positioned. An inboard fence, located adjacent to one side of the movable support portion, serves as a guide for a block as it is moved through the transport section. Preferably, the movable support portion is oriented so that it is substantially horizontal. The stabilizer portion is located above the movable support portion and is vertically adjustable relative thereto. The movable support portion and the stabilizer portion are configured so that they are able to contact external surfaces of one or more blocks moved by the transport section. Preferably, the movable support portion and the stabilizer portion are configured to contact opposing external surfaces of a block so as to effectively grip a block being processed. The gripping ability of the transport section is enhanced by providing the stabilizer portion with one or more biasing elements that exert a force towards the movable support. 
         [0006]    A block modifying section is located to one side of the transport section and comprises one or more primary modifiers that have one or more hammer elements. The one or more hammer elements are configured and arranged to be actuated in a direction that is generally orthogonal to the side of the transport section. Preferably, with each primary modifier, there is a plurality of hammer elements arranged in a matrix or array. The hammer elements are attached to a housing so as to form a block modifying unit or module, which is operatively connected to a platform. The platform may be adjustably positioned relative to the transport section. Preferably, there are approximately 7 to approximately 15 hammer elements in each unit or module. Additionally, the unit or module may be angularly positioned relative to the transport section. Two or more units or modules may be positioned adjacent each other in a side-by-side relation. As will be appreciated, the two units act in concert with each other and are arranged so that they are in a vertically staggered relation. As will be appreciated, when a block of material is moved relative to the primary modifiers, the impact zones of the hammer elements will preferably overlap. Preferably, one end of the platform that holds the block modifying units is operatively connected to either the main frame or the movable support portion, while the other end of the platform is operatively connected to the stabilizer portion. When the stabilizer portion moves vertically relative to the main frame (and the movable support portion connected thereto), the position of the primary modifiers is automatically adjusted. In operation the hammer elements, which may have independent motion, are able to strike and impact a surface of a block in a vibratory fashion as the block is being moved relative to the primary modifiers. 
         [0007]    The block modifying section of the machine may also be provided with one or more secondary modifiers. The secondary modifiers may be used to dress the edges or arrises of the block so as to produce irregular edges. A preferred secondary modifier comprises a pair of rotatable drums. Each drum is provided with a plurality of radially extending teeth that are spaced about the surface of the drum and which are rigidly attached thereto. Preferably, the teeth have at least one impacting surface and are arranged in one or more circumferential rows, spaced axially from each other along the rotational axis of the drum. Preferably, the teeth in each circumferential row are evenly spaced from each other. And, preferably, adjacent circumferential rows of teeth are offset from each other. The rotatable drums are operatively connected to the main frame (or the movable support portion) and the stabilizer portion of the transport section, so that as the stabilizer portion is raised and lowered the upper drum automatically maintains its position to accommodate differently sized blocks. Preferably, the rotatable drums and are situated so that they may work several disparate, viewable edge sections of a block before it reaches the primary modifiers. 
         [0008]    Another embodiment of a secondary modifier includes one or more sub-units or sub-modules have one or more hammer elements. The hammer elements are configured and arranged to be actuated in a direction that is generally perpendicular to the longitudinal axis of the transport section. Preferably, the hammer elements of each sub-unit or module are arranged in a matrix or array. The hammer elements are attached to a housing, which is movably attached to a bracket and the bracket may be adjustably positioned relative to the transport section. Additionally, the sub-unit or module may be angularly positioned relative to the transport section. Two or more sub-units or modules are positioned so that they are able to work one or more arrises or edges of a block. In operation the hammer elements, which may have independent motion, are able to strike and impact selected portions of a block as it is being moved by the transport section of the machine. Preferably, the sub-units or modules and are situated so that they may work several disparate, viewable edge sections of a block after it passes the primary modifiers. However, it will be understood that the sub-units or modules may be positioned before the primary modifiers, if desired. 
         [0009]    The machine includes an inboard fence and adjustable outboard fences. The inboard fence, positioned along one side of the movable support portion, guides a block as it moves through the machine. A preferred embodiment of an outboard fence comprises a flexible, endless belt that is positioned about the rotatable elements and held in tension due to the spring-biased arms. In use, the outboard fence is located adjacent to and slightly above the surface of the movable support portion so that the belt (and the spring biased rotatable elements) is able to contact the rear (or non-worked) surfaces of one or more blocks as they are being processed by the machine. Preferably, the outboard fence may be adjustably positioned towards and away from the transport section so as to accommodate different sized blocks. 
         [0010]    In an alternative embodiment, the outboard fence comprises an elongated body that includes first and second ends, a first or horizontal wall, and a second or vertical wall. Preferably, the fence is movably positionable relative to the inboard fence so as to accommodate blocks having different depths (the z dimension in a three dimensional coordinate system). 
         [0011]    The machine may be provided with an optional upper outboard fence that is associated with the stabilizer portion of the transport section. The upper fence comprises an elongated body that includes first and second ends, a first or horizontal wall and a second or vertical wall. The upper fence may include a third wall that is connected to the first and second walls, and which is angled relative thereto. The third wall presents a surface that can guide a block by contacting an upwardmost extending rear edge thereof. The position of the upper outboard fence may be adjusted in the y and z directions in a three dimensional coordinate system to accommodate blocks having different heights and depths. 
         [0012]    The above machine may be used with a wide variety of preformed building blocks having a wide variety of sizes and surface textures. And, with a single machine, it is possible to work a single or multiple areas of an exterior surface. However it is envisioned that two single surface machines can be connected to each other in an end-to-end manner so that the output end of a first machine confronts the input end of the second machine, and so that the block modifying section of the first machine and the block modifying section of the second machine face work opposite surfaces of a block. 
         [0013]    The machines described here are able to dress externally viewable surfaces of a building block, increase the speed at which rustic masonry blocks may be fabricated, and use a transport section to effectively grip one or more blocks as they are processed by the machine. 
         [0014]    These machines have a block modifying section that includes one or more hammer elements that percussively engage an externally viewable surface of a block. They may be adjusted to provide different knapping depths, or to accommodate differently sized blocks. 
         [0015]    An advantage of the machines is that externally viewable surfaces of a block may be randomly impacted by a plurality of hammer elements whose impact zones overlap. 
         [0016]    Another advantage is that various externally viewable surfaces of a block may be selectively processed. 
         [0017]    A third advantage is that the machines are able to accommodate a variety of differently shaped blocks. 
         [0018]    Yet another advantage of the invention is that a plurality of building blocks may be dressed in an expedient and efficient manner. 
         [0019]    These and other objectives, features and advantages will appear more fully from the following description, made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views. And, although the disclosure hereof is detailed and exact, the physical embodiments herein disclosed are merely examples that may be embodied in other specific structures. While preferred embodiments have been described, the details may be changed without departing from the claims. 
     
    
     
       DESCRIPTION OF THE DRAWINGS  
         [0020]      FIG. 1  is a perspective representation of an embodiment of a block dressing machine; 
           [0021]      FIG. 2  is a front elevational view of the block dressing machine of  FIG. 1 ; 
           [0022]      FIG. 3  is a left side elevation view of the block dressing machine of  FIG. 1 ; 
           [0023]      FIG. 4  is a right side elevational view of the block dressing machine of  FIG. 1 ; 
           [0024]      FIG. 5  is a top plan view of the block dressing machine of  FIG. 1 ; 
           [0025]      FIG. 6   a  is a front perspective view of the stabilizer portion and the crossbeam or carriage of  FIG. 1 ; 
           [0026]      FIG. 6   b  is a rear perspective view of the stabilizer portion and the crossbeam or carriage of  FIG. 1 ; 
           [0027]      FIG. 7  is a partial perspective view of the movable support portion of the transport section, primary and secondary block modifiers, and the outboard and inboard fences of  FIG. 1 ; 
           [0028]      FIG. 8   a  is a skeletonized, front elevational view of a block modifying section; 
           [0029]      FIG. 8   b  is a top plan view of  FIG. 8   a;    
           [0030]      FIG. 9  is a front elevational view of primary modifier units attached to a platform; 
           [0031]      FIG. 10   a  is a perspective view of a primary modifier; 
           [0032]      FIG. 10   b  is a front plan view of the primary modifier of  FIG. 10   a;    
           [0033]      FIG. 10   c  is a side elevational view of the primary modifier of  FIG. 10   a;    
           [0034]      FIG. 10   d  is a top plan view of the primary modifier of  FIG. 10   a;    
           [0035]      FIG. 11  is a perspective view of an alternative secondary block modifiers as they may be positioned adjacent the movable support and stabilizer portions of the transport section; 
           [0036]      FIG. 12  is a perspective view of an embodiment of a fence; and 
           [0037]      FIG. 13  is a perspective view of another preferred embodiment. 
       
    
    
     DETAILED DESCRIPTION  
       [0038]    In a preferred embodiment, the machine  10  of the present invention comprises a main frame  20 , a transport section  12 , and a block modifying section  18 . The main frame  20 , as shown in  FIGS. 1-4 , includes a bed and a superstructure that are supported by a plurality of horizontal beams  30 ,  32 ,  34 ,  36 ,  40 ,  42 ,  44 ,  46  and vertical legs  22 ,  24 ,  26 ,  28 . The superstructure extends vertically over the bed in a cantilevered fashion. The transport section  12 , which includes a movable support portion  56  with a horizontal movable surface  84  and a stabilizer portion  58 , are connected to the bed and the superstructure, respectively. Preferably, the stabilizer portion  58  may be selectively positioned in the vertical direction, relative to the movable support portion  56 . This allows the transport section  12  to accommodate blocks having different sizes and shapes to be processed by the machine  10 . 
         [0039]    The preferred movable support portion  56  is a conveyor that includes an elongated box-shaped frame  60  with an upper surface (not shown) opposite ends that rotatably support cylindrically shaped rollers  64 ,  66 , and an endless belt  70  is entrained about the upper surface and the rollers. The movable support portion  56  is movably powered by a conventional motive source  74  such as a hydraulic or electric motor and a coupler  75 . The endless belt  70  is generally horizontal and is of sufficient width and length so as to be able to support one or more blocks placed thereon. A preferred inboard fence  80 , located adjacent to one side of the movable support portion  56 , serves as a guide for a block as it is moved through the machine  10  by the transport section  12 . The inboard fence  80  comprises an elongated body  82  having planar horizontal upper surface  84  and a plurality of vertical walls  86 ,  88 ,  90 , with the walls in longitudinal alignment with each other along the elongated body. Between the walls  86 ,  88 ,  90  of the inboard fence  80 , there are gaps  92 ,  94 ,  96  that provide relief for portions of the block modifying section  18 . As can be seen in  FIGS. 8   a,    8   b,  and  11 , the gaps  92 ,  94 ,  96  enable teeth  208  of rotatable drum  204  and hammer elements  152  and  236  of impacting units  162  and  234 , respectively, to engage selected portions of a viewable surface of a block. 
         [0040]    The preferred stabilizer portion  58  is also a conveyor that includes an elongated box-shaped frame  100  with a lower surface (not shown), opposite ends that rotatably support cylindrically shaped rollers  110 ,  112 , and an endless belt  114  is entrained about the lower surface and the rollers. The stabilizer portion  58  is movably powered by its own conventional motive source  118  such as a hydraulic or electric motor that is connected to the stabilizer portion  58  by a coupler  119 . In use, the stabilizer portion  58  is positioned vertically, relative to the movable support portion  56  such that the outer (or bottom) surface of the belt  114  is able to contact upper surfaces of one or more blocks positioned on top of the movable support portion  56 . 
         [0041]    The stabilizer portion  58  is operatively connected to a horizontally oriented crossbeam or carriage  120  that is movably connected to the superstructure  48  of the main frame  20 . The preferred crossbeam or carriage  120 , which extends substantially along the length of the machine  10 , includes opposing ends with vertically aligned apertures  122 ,  124 , each of which slidingly receives a vertical guide column  50 ,  52  that is connected to the frame  20 . The crossbeam or carriage  120  is connected to a pair of vertical jack screws  130 ,  132  (shown covered by flexible, protective tubes) that are rotatably mounted to the superstructure  48 , and which extend downwardly into threaded apertures  126 ,  128  at the ends of the crossbeam  120 . Both of the jack screws  130 ,  132  are operatively connected by gearing and drive shafts  144  to a single motive source  146  such as a hydraulic or electric motor. In operation the motive source  146  rotates the jack screws  130 ,  132  in concert, which, in turn, moves the crossbeam  120  (and the stabilizer portion  58  connected thereto) in a vertical direction, as desired. 
         [0042]    In operation, the movable support portion  56  and the stabilizer portion  58  are configured to contact external surfaces of one or more blocks as they move through the transport section  18 . Preferably, the movable support portion  56  and the stabilizer portion  58  are configured to contact opposing external surfaces of a block so as to effectively grip a block being processed. The gripping ability of the transport section  18  is enhanced by providing the stabilizer portion  58  with one or more biasing elements  102  that exert a force towards the movable support portion  56 . A preferred biasing element  102  is in the form of a resilient panel  104  having a generally z-shaped cross-section, with the panel having an upper arm segment  106 , a diagonally oriented body, and a lower leg segment  108 , is shown in an inset in  FIG. 6A . In use, the upper arm segment  106  is preferably connected to the stabilizer portion  58  so that it faces the input end of the transport section  18  and the lower leg segment  108 , which bears against the inside surface  73  of the conveyor belt  70 , faces towards the output end of the transport section  12 . Preferably, there is a plurality of resilient panels  104 , arranged in a sequential order between the end rollers  110 ,  112 , which bias a significant portion of the bottom surface of the belt  114  of the stabilizer portion  58  towards the movable support portion  56 . If a block having a vertically extending protrusion (such as, for example, an interlocking lip on the bottom surface of an inverted block) passes through the transport section  12 , the biasing elements  102  will automatically compensate for such variation, and the belt  114  will be able to maintain contact with the block. Other types of biasing elements  102  may be used. For example, resiliently mounted rollers. In operation, the belts  70 ,  114  of the movable support portion  56  and the stabilizer portion  58  preferably move at the same speed, which can range from about 0-to-100 feet per minute. 
         [0043]    Generally, the block modifying section  18  is located to one side of the transport section  12  and comprises one or more primary modifiers  150  and one or more secondary block modifiers  200 ,  230 . A preferred primary modifier  150  is a generally rectangularly shaped housing  162  having an exterior surface  164  with a top, a bottom, sides, a back and a front. The rectangular housing  162  forms a modifying unit or module  150  that is used to work a major, viewable surface of a block. To that end, the modifying unit or module  150  is provided with one or more hammer elements  152  that are movably connected thereto, and which protrude from apertures  168  in the front  166  of the modifying unit. Preferably, there are approximately 7 to approximately 15 hammer elements  152  in each modifying unit or module  150 , with the hammer elements arranged into a pattern or matrix. More preferably, each unit or module  150  includes 11 hammer elements  152  arranged in two offset rows. 
         [0044]    The housing  162  is operatively connected to a frame or platform  170  so that the hammer elements  152  face the transport section  12 . The platform  170  may be adjusted in one of several directions, relative to the transport section  12 . That is, the platform  170  may be adjusted so that the hammer elements  152  are able to be repositioned towards and away from the transport section  12 , as desired. A preferred adjustment mechanism comprises a pair of jack screws that are operatively connected to the main frame  20  and which drivingly engage the platform  170  so that it may move relative to the transport section  12 . Preferably, the jack screws are connected to each other by way of sprockets  185  and a chain  187  so that they are able to operate in concert. A motive source  189  such as a hydraulic or electric motor may be used to power the adjustment mechanism. As the hammer elements  152  are moved closer to the transport section  12 , the amount of block material that can be removed increases. 
         [0045]    Additionally, the platform  170  may be adjustably angled, relative to the transport section  12 . To facilitate such adjustability, one end  172  of the platform  170  is pivotally connected to a shaft  182  that extends perpendicularly from the movable support portion  56 . The other end  172  of the platform is operatively connected to the stabilizer portion  58  by way of a link  184 . The link  184  compensates for changes in the distance between the movable support portion  56  and stabilizer portions  58 . Moreover, as the stabilizer portion  58  is raised and lowered the platform  170  will pivot about the horizontal shaft  182  and automatically position the hammer elements  152  relative to the transport section  12 . In operation, the platform  170  has a preferred angular range of about 0 to about 25 degrees. 
         [0046]    Preferably, two or more units or modules  150  positioned adjacent each other in a side-by-side relation on the platform  170 . As shown in  FIG. 9 , the modifying units  150  are attached to the platform  170  at different elevations. It has been discovered that such an arrangement enables the impact zones of the hammer element to overlap, producing a more uniformly rustic-appearing surface. Preferably, one of the primary modifiers  150  is provided with spacers or blocks  178  interposed between the upper surface  176  of the platform  170  and the bottom surface of the primary modifier housing  162 . The two units  150  act in concert with each other and are arranged so that they are in a vertically staggered relation so that the impact zones of the hammer elements  152  overlap. 
         [0047]    Each preferred hammer element  152  has a shaft  154  having a diameter  155  of about 1.00 inch (2.54 cm), and includes one end that is operatively connected to a drive source such as a pneumatic drive source. The other end of the shaft  154  has a removable working end  156 , which may have one of several differently shaped impacting surfaces. For example, the impacting surface  156  may be substantially flat, hemispherical, or may include a plurality of projections that terminate in flats and points. Each hammer element  152  reciprocates, and preferably, each hammer element has a stroke that varies by as much as 1.50 inches (3.82 cm). This enables the hammer elements  152  to work planar surfaces as well as surfaces that have convexities and concavities. Preferably, each hammer element  152  has an operational cycle or vibrational speed of approximately 1,500 to 4,000 cycles per minute. 
         [0048]    In operation each hammer element  152  independently strikes and impacts a surface of a block being moved by the transport section  12  of the machine  10 . An advantage of such independent motion is that the hammer elements  152  are able to work and otherwise process block surfaces that include convex and concave surfaces. Preferred hammer elements  152  are available through Trelawny SPT Ltd., of 13 Highdown Road, Leamington Spa, Warwickshire, CV31 1XT, United Kingdom. It is understood, however, that other similar reciprocating devices may be used without departing from the spirit and scope of the invention. 
         [0049]    The secondary modifiers  200  may dress or otherwise work the viewable edges or arrises of the block to produce irregular edges. A preferred secondary modifier  200  comprises first and second rotatable drums  202 ,  204 . More specifically, each drum  202 ,  204  includes a body having a plurality of outwardly extending teeth  206 ,  208 . The teeth  206 ,  208  may be attached to the body in a conventional manner, such as welding, or bolting. Alternatively, the teeth  206 ,  208  may be integral to the body. The first rotatable drum  202  is operatively connected to the main frame  20  of the machine  10  by a shaft  210  and adjustable pillow blocks  211 . Note that the shaft  210  is substantially parallel to the longitudinal axis of the transport section  12 . The first drum  202  is connected by conventional pulleys  214  and a drive belt  218  to a motive source  222  such as an electric or hydraulic motor. As depicted, the first drum  202  is adjacent the movable support portion  56  so that the teeth  206  of the first drum protrude into a gap  92  in the inboard fence  80 . As will be understood, the position of the first drum  202 , relative to the movable support portion  56 , is adjustable closer to or further away from the movable support portion, which changes the extents to which the teeth  206  protrude through the gap  92  in the inboard fence  80 . 
         [0050]    The second rotatable drum  204  is operatively connected to the crossbeam or carriage  120  of the machine  10 , also by a shaft  212  and pillow blocks  213 . As with the shaft  210  that supports the first drum  202 , the shaft  212  that supports the second drum  204  is substantially parallel to the longitudinal axis of the transport section  12 . The second drum  204  is connected by conventional pulleys  216  and a drive belt  220  to a motive source  224  such as an electric or hydraulic motor. As depicted, the second drum  204  is adjacent the stabilizer portion  58 . Note that an upper, inboard fence is not needed. The pillow blocks  213  to which the shaft  212  is connected, may be adjustable so that the second drum  204  can be adjusted relative to the stabilizer portion  58 . Although it is possible to arrange the first and second drums  202 ,  204  so that their respective teeth are vertically aligned with each other, it is advantageous to position the first and second drums so that the teeth are offset from each other in the longitudinal direction of the transport section  12 . In operation, the second drum  204 , which is connected to the stabilizer portion  58  of the transport section  12 , automatically adjusts to differently sized blocks as the stabilizer portion is raised and lowered. Preferably, the rotatable drums  202 ,  204  work several disparate, viewable sections of a block before the block reaches the primary modifiers  150 . It will be understood, however, that the rotatable drums  202 ,  204  may be positioned at other locations on the machine  10  without departing from the spirit and scope of the invention. 
         [0051]    Another embodiment of a preferred secondary modifier  230  includes one or more sub-units or sub-modules  232 ,  234  that each have one or more hammer elements  236  acting generally perpendicular to the longitudinal axis of the transport section  12 . Each sub-unit or module  232 ,  234  includes a plurality of hammer elements  236  arranged in a matrix or array. The hammer elements  236  are attached to a housing  246 , which is movably attached to a bracket  254 ,  256 . The bracket  254 ,  256  may also be adjustably positioned relative to the transport section  12 . Thus, each sub-unit or module  232 ,  234  may be positioned in a plurality of orientations and positions relative to the transport section  12 . 
         [0052]    Each sub-unit or module may include approximately 1 to approximately 5 hammer elements. However, it is preferred that each sub-unit or module include approximately 2 to approximately 4 hammer elements. As with the primary modifiers  150  discussed above, each preferred hammer element  236  of the secondary modifiers  232 ,  234  has a shaft  238  having a diameter  239  of about 1.00 inch (2.54 cm), and includes one end operatively connected to a drive source such as a pneumatic drive source. The other end of the shaft  238  has a removable working end  240 , which may have one of several differently shaped impacting surfaces. Each hammer element  236  reciprocates and preferably, each hammer element has a stroke that varies by as much as 1.50 inches (3.82 cm). Preferably, each hammer element  236  has an operational cycle or vibrational speed of approximately 1,500 to 4,000 cycles per minute. 
         [0053]    Preferably, there are two or more sub-units or modules  232 ,  234  that can be adjustably positioned so that they are able to work one or more arrises or edges of a block. In operation each hammer element  236  independently strikes and impacts a surface of a block being moved by the transport section  12  of the machine  10 . The sub-units or modules  232 ,  234  are operatively connected by way of brackets  254  to locations adjacent the movable support  56  and stabilizer portions  58  of the transport section  12 , respectively. Preferably, the sub-units or modules  232 ,  234  work surfaces of a block after the block passes the primary modifiers  150 . However, it will be understood that the sub-units or modules  232 ,  234  may be positioned before the primary modifiers  150 , if desired. An advantage of such independent motion is that the hammer elements  236  are able to work and otherwise process block surfaces that include convex and concave surfaces. Preferred hammer elements are available through Trelawny SPT Ltd., of 13 Highdown Road, Leamington Spa, Warwickshire, CV31 1XT, United Kingdom. It is understood, however, that other similar reciprocating devices may be used with out departing from the spirit and scope of the invention. 
         [0054]    The machine  10  may be provided with an outboard fence or fences  14  that may be connected to the movable support  56  and/or the stabilizer portions  58 , respectively. In a preferred embodiment, a lower outboard fence  14  includes a plate  260  with an upper horizontal surface  266  having two ends  262 ,  264 . At each end  262 ,  264  of the plate  260  there is a vertical shaft  268 ,  270  about which a rotatable element  272 ,  274  such as a wheel or pulley is mounted. In the space between the end wheels  272 ,  274 , the plate  260  supports a plurality of horizontally oriented arms  276 . One end of each arm  278  is pivotally connected to vertical shafts  282  extending from the plate  260 , and the other end  280  of each arm  276  is provided with a vertical shaft  284  that supports a rotatable element  286 , such as a wheel or pulley. Each arm  276  is operatively connected to a spring element  288  that biases the arm  276  in a predetermined direction towards one side of the plate  260 . A belt  290  is positioned about the rotatable elements  286  and held in tension due to the effect of the spring-biased arms  276 . In use, the lower fence  14  is positioned adjacent to and slightly above the horizontal surface  266  of the movable support portion  56  so that the belt  290  (and the spring biased rotatable elements  286 ) is able to contact the rear surfaces of one or more blocks as they are being processed by the machine  10 . Note that the wheeled ends of the arms  280  preferably trail the pivoted ends  278  of the arms  276 . 
         [0055]    The lower fence  14  may include a pair of transversely oriented, horizontal sleeves  292 ,  294  that are attached to a lower surface of the plate  260 . The sleeves are movably mounted to horizontally struts  296 ,  298  that extend from the movable support portion  56  of the transport section  12 . Each strut includes a jack screw that engages internal threads of each sleeve. The jack screws are connected to each other by sprockets and a chain, with one of the ends of the jack screws including a crank arm or similar mechanism. The lower fence  14  may be moved towards and away from the transport section  12  so as to accommodate different sized blocks. 
         [0056]    In an alternative embodiment, the lower outboard fence may comprise an elongated body that includes first and second ends, a first or horizontal wall, and a second or vertical wall. The outboard fence includes one or more rearwardly extending arms that may be operatively connected to horizontal struts  296 ,  298  that are connected to the main frame  20  through the movable support portion  56 . Preferably, the outboard fence is movably positionable relative to the horizontal struts  296 ,  298  so that the distance between the lower, outboard fence and the inboard fence  80  can be varied to accommodate blocks having different depths (the z dimension in a three dimensional coordinate system). 
         [0057]    The machine may also be provided with an optional upper outboard fence that comprises an elongated body that includes first and second ends, a first or horizontal wall and a second or vertical wall. The upper fence may include a third wall that is connected to the first and second walls, and which is angled relative thereto. The third wall presents a surface that can guide a block by contacting an upwardmost extending rear edge thereof. The upper, outboard fence includes one or more rearwardly extending arms with upwardly extending posts that may be operatively connected to horizontal struts by way of tubular brackets. The horizontal struts are preferably connected to the carriage or cross beam  120 , to which the stabilizer portion  58  of the transport section  12  is connected. The position of the elongated body may be adjusted in the y and z directions in a three dimensional coordinate system to accommodate blocks having different heights and depths. Optionally, an adjustment mechanism comprising sprockets and a chain is operatively connected to jack screws in the horizontal struts. This allows the upper fence to be moved towards and from the stabilizer portion  58  in a substantially parallel manner. 
         [0058]    The foregoing is considered as illustrative only. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, the exact construction and operation shown and described is only an example of a preferred embodiment. The invention is defined by the following claims.