Abstract:
A mold extractor assembly for use with a concrete products forming machine of a type having mold mount shelves and a feed box assembly mounted behind the mold mount shelves and moveable in a vertical and horizontal direction to dispense concrete into cavities defined within a mold box mounted on the shelves. The mold extractor assembly comprises a guide rail assembly horizontally oriented along and vertically moveable with the feed box assembly. An extractor arm assembly is moveable along the guide rail assembly in a horizontal direction toward the mold mount shelves. An extractor fork assembly is telescopically nested about the extractor arm assembly and configured to extend a horizontal reach of the mold extractor assembly to beyond the mold mount shelves so that the mold box can be lifted off of the mold mount shelves via the extractor fork assembly and carried forwardly to a mold transfer assembly.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates generally to mold box assemblies and more particularly to such assemblies which are used to form molded products such as concrete products and which include structures for assisting in the exchange of one mold box with another within a concrete products forming machine (CPM). 
         [0003]    2. Description of the Prior Art 
         [0004]    Prior art machines for forming concrete products within a mold assembly include a product forming section comprising a stationary frame, an upper compression beam and a lower stripper beam. The mold assembly includes a head assembly that is mounted on the compression beam, and a mold box that is mounted on the frame and receives concrete material from a feed drawer. An example of such a system is shown in U.S. Pat. No. 5,807,591 which describes an improved concrete products forming machine (CPM) assigned in common to the assignee of the present application and herein incorporated by reference for all purposes. 
         [0005]    In use, the feed drawer moves concrete material over the top of the mold box and dispenses the material into the contoured cavities of the mold box. The feed drawer typically includes an agitator assembly within the drawer that operated to break up the concrete and improve its consistency prior to dropping it into the mold. As the concrete material is dispensed, a vibration system shakes the mold box to spread the concrete material evenly within the mold box cavities in order to produce a more homogeneous concrete product. A wiper assembly, mounted to the front of the feed drawer, acts to scrape excess concrete from the shoes when the feed drawer is moved to an operative position above the mold box. 
         [0006]    After the concrete is dispensed into the mold cavities, the feed drawer retracts from over the top of the mold box. A spreader, bolted separately to the front of the feed drawer, scrapes off excess concrete from the top of the mold when the feed drawer is retracted after filling the mold cavities. The compression beam then lowers, pushing shoes from the head assembly into corresponding cavities in the mold box. The shoes compress the concrete material during the vibration process. After compression is complete, the stripper beam lowers as the head assembly pushes further into the cavities against the molded material. A molded concrete product thereby emerges from the bottom of the mold box onto a pallet and is conveyed away for curing and a new pallet moved in its place beneath the underside of the mold assembly. 
         [0007]    The mold box and head assembly are matched together and configured to form concrete products in a specific shape, size, and number. Each product configuration requires a different mold. When the operator desires the CPM to produce products in different configurations, the mold must be detached from mounts on the CPM and removed along with the assembly. A different mold box and head assembly must then be moved into place and mounted within the CPM. 
         [0008]    Conventional methods for changing molds out in a CPM are typically labor intensive and result in a lot of downtime with the machine, leading to lost revenue. Accordingly, there is need for an improved system and method for better automating the process for changing molds within a concrete products forming machine that minimizes these drawbacks. 
       SUMMARY OF THE INVENTION 
       [0009]    The invention consists of a two stage, well guided, hydraulic cylinder actuated telescoping mechanism attached to the underside of a top plate assembly of the feed drawer section of a concrete products forming machine. The two stage telescoping function allows the device to discretely position a mold in one of two horizontal positions, the first extended position is where the mold assembly is raised and lowered off of or onto the die supports with mold alignment dowels of the upper vibrator assembly located in the center section assembly of the concrete products forming machine. The second extended position is where the mold assembly is raised or lowered off of or onto a mold transfer cassette. A third fully retracted position keeps the mechanism stored when mold changes are not being performed. The vertical motion is controlled by an axis of motion already used in adjusting the top plate assembly of the feed drawer section of the concrete products forming machine into place for production. 
         [0010]    The invention includes several new and useful features. First, the discrete horizontal positions and the use of tapered alignment blocks eliminate the chance of horizontal misalignment during the mold change process. Second, the telescoping functionality reduces the space requirements for operation and shipping, keeping the device within the envelope of the basic machine. Additionally, using the vertical motion of the existing top plate assembly eliminates the need for dedicated actuators to position the mold extractor assembly. 
         [0011]    The purpose of the invention is to allow a mold assembly to be removed from the machine automatically and without use of hand tools or external overhead lifting devices, providing an increased isolation of the operator from the dangers associated with most mold change processes of industrial concrete product forming machines. This invention has the advantage of not requiring an additional vertical axis of motion by using the existing axis of the top plate assembly of the feed drawer section of the concrete products forming machine. An additional advantage of this system is its modular nature, allowing it to be integrated into an existing concrete products forming machine, thereby reducing the machine cost whereas many existing systems are integral to the machine and cannot be purchased without it. 
         [0012]    The foregoing and other objects, features and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment of the invention that proceeds with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a perspective view of a mold extractor assembly of the present invention in a first extended position relative to a mold box assembly and mold cassette assembly. 
           [0014]      FIG. 2  is a perspective view of the mold extractor assembly of  FIG. 1  shown in a retracted position. 
           [0015]      FIGS. 3A and 3B  are perspective and top plan views, respectively, of the mold extractor assembly of  FIG. 1  shown in a fully extended position. 
           [0016]      FIG. 4  is a side elevation view of the mold extractor assembly of  FIG. 1  installed within a feed box assembly of a concrete products forming machine with a mold assembly and mold cassette assembly shown in broken lines. 
           [0017]      FIG. 5A through 5C  are side elevations views of the mold extractor assembly in progressive extension and elevation steps during a mold extraction process. 
           [0018]      FIG. 6  is a front elevation view of the mold extractor assembly taken along lines  6 - 6  in  FIG. 4 . 
           [0019]      FIG. 7  is a front elevation magnified view showing a portion of the mold extractor assembly lifting a mold assembly off of shelves and alignment dowels of a concrete products forming machine according to teachings of the invention. 
           [0020]      FIG. 8  is a side elevation section view of  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION 
       [0021]      FIG. 1  shows a mold extraction assembly  10  in combination with a mold assembly  110  and mold cassette assembly  210 . Extraction assembly  10  includes a set of inner guide rails  12 ,  14  coupled along their length to a top plate assembly of the feed drawer section of a concrete products forming machine ( FIG. 6 ). Guide rails  12 ,  14  extend parallel to a mold extraction path  16  and include grooves running longitudinally along the length of the rails on opposed sides. A pair of mold extraction arms  18 ,  20  are disposed just underneath the inner guide rails  12 ,  14  and are slidingly connected thereto via sets of guide blocks, such as extraction arm guide block  22 , that are affixed to upper ends of the arms  18 ,  20  and slide within the grooves formed in the sides of the guide rails. 
         [0022]    Extraction arms  18 ,  20  are coupled together via a front bracing plate  24  and a rearwardly disposed cross-bracing plate  26  running between top ends of the arms. A hydraulic cylinder  28  is positioned along a central axis of the extraction assembly  10  and includes a cylinder mount block  30  at a rear end and a cylinder support block  32  at a front end mounted upward to the top plate assembly of the feed drawer section of the concrete products forming machine. A cylinder housing  34  is fixedly coupled between the mount block  30  and support block  32  and receives a hydraulic piston  36 . A terminal end of the hydraulic piston  36  is coupled to an underside of the cross-bracing plate  26  spanning between extraction arms  18 ,  20 . Actuation of the hydraulic cylinder  28  causes the piston  36  to extend out of the end of the housing  34  and push the plate  26 , thereby causing the connected arms  18 ,  20  to slide forwardly along the inner guide rails  12 ,  14  to an extended position. Likewise, the hydraulic piston  36  may be retracted into the housing  34  and withdraw the arms  12 ,  14  to a retracted position as shown in  FIG. 2 . 
         [0023]    Mold extraction assembly  10  further includes a set of outer guide rails  38 ,  40 , with each affixed to outside walls of respective extraction arms  18 ,  20  and extending parallel to the inner guide rails  12 ,  14  and mold extraction path  16 . A pair of mold extraction forks  42 ,  44  are telescopically nested about the arm assembly and slidingly coupled to respective arms  18 ,  20  via a set of guide blocks, such as extraction fork guide block  46  (hidden in  FIG. 1 , but shown in  FIG. 3B ), that allow the forks to move slidingly along the length of the rails  38 ,  40  and extend the forward reach of the mold extraction assembly  10 . Forks  42 ,  44  are coupled together at a front end by a spreader plate  48 . Each of the forks includes a tapered alignment block, such as blocks  50 ,  52 , that extend upward from a top surface of the forks and mate (see broken lines) with complementary apertures ( FIG. 7 ) formed on the underside of a mold assembly  110 . The tapering narrows to the upper surface of the alignment blocks  50 ,  52 , preferably in the direction of extraction  16  so as to accommodate for tolerances with positioning the forks in relation to the mold assembly  110  as described further below. More preferably, the tapered surface has a principal taper in a direction parallel with the outside track, and a minor taper in a horizontally orthogonal direction to that track. Forks  42 ,  44  are profiled with an angled surface  54  coupling the thicker rear end with the narrower front end to optimize section stiffness and weight. 
         [0024]    Horizontal movement of the arm assembly is implemented by a pair of hydraulic cylinders  58 ,  60  coupled via a bracket (e.g. bracket  62 ) affixed to a back end of respective extraction arms  18 ,  20 . Cylinders each include a cylinder housing  64  fixedly coupled to bracket  62  and a hydraulic piston  66  received in the housing and extending parallel to the extraction path  16 . A terminal end of the hydraulic piston  66  is coupled to a rear end of a respective fork  44 . Actuation of the hydraulic cylinders  60  causes the piston  66  to extend out of the end of the housing  64  and push the fork  44 , thereby causing the fork assembly to slide forwardly along the outer guide rails  38 ,  40  to an extended position. Likewise, the hydraulic piston  66  may be retracted into the housing  64  and withdraw the forks  42 ,  44  to a retracted position as shown in  FIG. 2 . 
         [0025]    Vertical movement  56  of the mold extraction assembly  10  via means described further below acts to approach and lift the mold assembly  110  from below so it can be placed on either the concrete products machine shelves  134  or the cassette assembly  210  shelves  264 ,  266  during a mold exchange process. Retraction and extension of the mold extraction assembly occurs in three phases: (1) the fully retracted position is shown in  FIG. 2 ; (2) the partially extended position is shown in  FIG. 1  so that the forks  42 ,  44  are positioned below mold assembly  110  mounted on a CPM; and (3) the fully extended position as shown in  FIGS. 3A / 3 B where both the forks and the arms are extended along respective rails/tracks  38 ,  40 ,  12 ,  14 . 
         [0026]    The mold assembly  110  includes a mold box portion  112  and a head assembly portion  114  that are fitted together in alignment with one another for mounting together onto a concrete products forming machine as described further below. Assemblies  112  and  114  are constructed to form mold concrete products having a certain size and configuration, whereas different mold assemblies can have differently configured assemblies resulting in different products. As the exchange of one mold assembly with another on a concrete products forming machine typically requires a large amount of manual labor and downtime, enabling an automated exchange of one mold assembly with another using the extraction assembly described herein is a key goal of the invention. 
         [0027]    Generally, mold box  112  includes a body with a front wall and a back wall joined together with side walls and having cavities for receiving and molding the concrete products. The side walls each have a side face that spans between a bottom facing surface of the side face and a top facing surface. 
         [0028]    A mounting bracket extension  132  is coupled to each side wall of the mold box  112  to extend the width of the mold assembly  110 . In use, the front and back walls of the mold box  112  are sized for extending substantially between a pair of shelves  134  ( FIG. 7 ), also referred to as die supports  134 , on a concrete product forming machine to thus allow the mold box  112  to sit directly on top of and span between the shelves. The mounting bracket extensions  132  can be used to extend narrower mold boxes to mount to various CPMs, although such features may not be necessary if the bottom facing surfaces of the sidewalls are wide enough to accommodate the die alignment and mold transfer features described further below. The mounting bracket extensions  132  in combination with the side walls thus form the lower mounting surface of the mold assembly onto these shelves  134  of the concrete products forming machine. 
         [0029]    Formed in an underside of this lower mounting surface are die alignment holes  136  ( FIG. 7 ) adjacent an outer periphery of the mold box. When a mounting bracket extension  132  is necessary for extending the width of the mold assembly  110 , these die alignment holes  136  are formed in each mounting bracket extension and configured to receive a respective alignment dowel  138  ( FIG. 7 ) extending upward from the shelves of the concrete products forming machine. 
         [0030]    Mold transfer locators  140  ( FIG. 7 ) are formed on the lower mounting surface of the mold box  112 , inboard of the die alignment holes and shelves of the concrete products forming machine. In one embodiment, locators  140  are recesses formed in the lower mounting surface that extend to an inner wall of the mold side walls. Locators  140  are configured to precisely locate the mold box onto mold extractor forks  42 ,  44  when the mold box is lifted off of the alignment dowels by the mold extractor forks during a mold extraction process as described further below. In use, these mold transfer locators  140  receive the tapered alignment blocks  50 ,  52  formed atop the forks  42 ,  44  of the mold extraction device  10 . The forks  42 ,  44  of the extraction device  10  are configured to move between the CPM shelves  134  and lift upward against the inward portion of the lower mounting surface of the mold assembly, this inward portion being that portion that does not sit directly atop the CPM shelves.  FIG. 7  illustrates fork  44  lifting up against a lower portion of mold box  110  that is inboard (e.g. to the left) of the bracket extension  132 . The tapered alignment blocks are received within the mold transfer locators, e.g. block  52  received within locator  140 , and the mold assembly  110  is lifted off of the shelves  134  for transport away from the CPM. A new mold box is then installed on the CPM in a reverse process and the production cycle is then restarted to form newly configured molded products. 
         [0031]      FIG. 1  shows details of the cassette  210  used in mold transfer assembly. Cassette  210  includes two C-section frames  252 ,  254  coupled together at the top by a central weldment post  256  on which sits a top plate  258 . Cassette frame sections  252 ,  254  are coupled together at the bottom by a spreader plate  260  that maintains the spacing between the frame sections. Spreader plate is located at the lowest portion of the cassette  210  so as to provide a large central opening  262  within the cassette through which a mold assembly, such as assembly  110 , may be received. 
         [0032]    Coupled on either side of the spreader plate  260  are features configured to guide and retain a mold assembly within the cassette. A pair of shelves  264 ,  266  are spaced on each side of the spreader plate  260 . The shelves are spaced an identical distance apart as the shelves or die supports  134  on the CPM to which the mold assemblies are operatively mounted. The pair of shelves  264 ,  266  are separated by a central expanse configured to receive the forks  42 ,  44  of a mold exchange assembly, noting that the spreader plate  260  is located below the bottom surface of the shelves to establish a height of the vertical expanse between the shelves  264 ,  266 . The height of the vertical expanse—and in this case the height of shelves  264 ,  266 —is large enough so as to accommodate the height of a front end of the mold extractor forks  42 ,  44  and prevent collision with the spreader plate  260  when the forks have set the mold assembly  110  onto the top surface of shelves  264 ,  266  and is then withdrawn back to a retracted position. 
         [0033]    A pair of inwardly sloped guide plates  268 ,  270  are coupled to outside peripheral sections of the shelves. These plates  268 ,  270  are angled from a wider top spacing to a narrower bottom spacing and are configured to provide surfaces that guide the mold onto the shelves. Mold alignment dowels  272  are centrally located on a top surface of each of the shelves  264 ,  266 . In use, the mold extraction device  10  would lift mold assembly  110  from the shelves  134  on the CPM and carry it through the opening  262  of cassette  210 . The mold extraction device would then lower the mold assembly  110  onto cassette shelves  264 ,  266  so that apertures on an underside of the mold assembly receive dowels  272 . 
         [0034]      FIG. 4  shows a side view of the mold extraction assembly  10  coupled to the underside of a feed drawer assembly  310 . Feed drawer assembly  310  is a structure located to the rear of a CPM center section (not shown) and the mold  110  mounted thereon (shown in broken lines). The mold extraction assembly  10  is coupled to a mounting plate  312  affixed to the underside of the feed drawer  314  of assembly  310 . Vertical movement  316  of the feed drawer  314  and coupled mold extraction assembly  10  is implemented via a set of screw lifts  318 ,  320  that would ordinarily be part of the feed drawer assembly system in a conventional CPM such as that available from Columbia Machine, Inc. The mold extraction assembly  10 , when in a fully retracted position as shown in  FIG. 4 , fits within the envelope of the feed drawer assembly  310  and uses the preexisting vertical lift system  318 ,  320  to raise and lower, particularly the forks  42 ,  44  of the extraction assembly  10  into contact with an underside of the mold assembly  110 . The mold assembly  110  is then lifted and carried forward along extraction route  16  to the cassette assembly  210  whereupon the mold is set down onto the cassette shelves  264 ,  266  and onto alignment dowels  272 . 
         [0035]      FIGS. 5A-5C  illustrate three separate extension phases of the mold extraction device  10 . In  FIG. 5A , the mold extraction forks  42 ,  44  are pushed forward  70  via hydraulic cylinders  58 ,  60  to an extended position so that the mold alignment block structures  50 ,  52  on the tops of the forks  42 ,  44  are aligned with complementary structures on the underside of mold assembly  110 . The feed box lifting structure  318 ,  320  then raise  72  the feed box and attached mold extraction assembly  10 , and alignment blocks  50 ,  52  are received within the complementary structures on the mold assembly and the mold is lifted off of the CPM shelves. 
         [0036]      FIG. 5B  shows the mold extraction assembly in a fully extended and raised position while retaining the mold assembly  110 . The mold extraction arms  18 ,  20  are pushed forward  74  via hydraulic cylinder  28  to an extended position so that—in combination with the mold extraction forks  42 ,  44  also having been fully extended—the mold alignment block structures  50 ,  52  are aligned within the opening of the cassette assembly  210  and spaced above its shelves  264 . 
         [0037]      FIG. 5C  shows the mold extraction assembly in a fully extended and lowered position. From the position shown in  FIG. 5B , the feed box lifting structure  318 ,  320  lowers  76  the feed box and attached mold extraction assembly  10  to thus set the mold assembly  110  onto the shelves of the cassette assembly  210 . More specifically, the mold assembly is lowered so that alignment dowels  262  located on a top surface of the shelves are received within complementary apertures formed on the lower surface of the mold assembly, outboard of the structures for receiving the alignment blocks on the forks. With the mold assembly now mounted on the cassette assembly  210 , the extraction assembly is retracted to the intermediary position shown in  FIG. 1 . Retraction of the extraction assembly forks  42 ,  44  is preferably just enough to move the forks out of the way of a mold transfer assembly that moves a new cassette and mold assembly into place for transfer to the concrete products machine  110 . In this way, it is preferred that the forks retract to the intermediary position shown in  FIG. 1  rather than the fully retracted position as shown in  FIG. 2  so as to save time. 
         [0038]      FIG. 6  shows a front elevation view of the mold extraction assembly  10  mounted via a bottom plate  312  to a feed box  314  within an assembly  310 . The mold extraction assembly is mounted upward against an underside of plate  312  as via bolts  78 ,  80  so that the assembly may be raised and lowered by means  318 ,  320  in fixed relation to the feed box  314 . 
         [0039]      FIG. 7  shows a magnified view of a right portion of the mold extraction assembly, and particularly fork  44  of such assembly lifting upward against a bottom side of the mold assembly  110 , and particularly upward against mounting bracket extension  132 . The extractor fork assembly is narrower than a space between the mold mount shelves so that the extractor fork assembly may fit within a space between the shelves and beneath the mold box mounted thereon. Upward movement of the fork  44  causes the alignment block  52  to be received within complementary aperture  140  formed inboard from the mold alignment aperture  136  on the bottom side of the mold assembly  110 . Further upward movement causes the mounting bracket extension  132  to be lifted off of CPM shelf  134  and particularly off of mold alignment dowel  138 . 
         [0040]      FIG. 8  shows a side elevation view in partial section of  FIG. 7  showing the mold assembly  110  lifted above the top level of CPM shelf  134 . When the dowel  138  is fully disengaged from aperture  136 , the mold extractor may be moved  16  ( FIG. 16 ) to a fully extended and lifted position as shown in  FIG. 5B . 
         [0041]    In summary, therefore, the mold extractor assembly is comprised of a mold extractor fork assembly which during mold change supports the mold assembly and is supported by the mold extractor arm assembly. Hydraulic cylinders are used to move the mold extractor fork assembly horizontally relative to the mold extractor arm assembly. 
         [0042]    The mold extractor fork assembly is comprised of two extractor forks to support the mold assembly, tapered alignment blocks that indicate the correct position of the mold assembly on the two extractor forks, and mounted linear runner blocks that guide the mold extractor fork assembly on horizontal guide rails mounted to the mold extractor fork assembly. Each extractor fork has means for attaching to the rod end of a hydraulic cylinder to move the extractor forks relative to the mold extractor arm assembly. 
         [0043]    The mold extractor arm assembly is comprised of two extractor arms that support the mold extractor fork assembly and are mounted to the top plate assembly of the rear feed drawer section. Horizontal guide rails are mounted to the extractor arms that support and guide the mold extractor fork assembly. Runner blocks are mounted to the extractor arms that are supported by guide rails mounted to the top plate assembly. The mold extractor arm assembly has a means for attaching the rod end of a hydraulic cylinder to move the mold extractor arm assembly relative to the top plate assembly. 
         [0044]    The mold assembly is comprised of two main sections, the mold head assembly and the mold box assembly. These two sections are placed together by the center section assembly to be ready for transport by the mold extractor assembly. The position of the mold assembly for transport by the mold extractor assembly is indicated by tapered alignment blocks fitting into like holes in the mold box assembly. 
         [0045]    Having described and illustrated the principles of the invention in a preferred embodiment thereof, it should be apparent that the invention can be modified in arrangement and detail without departing from such principles. For instance, it is understood that the hydraulic cylinders are just one aspect of drive means that can extend and retract the forks and arms of the mold extraction device and can take the form of hydraulics, pneumatics, electric screw-driven mechanisms, etc. We claim all modifications and variation coming within the spirit and scope of the following claims.