Patent Publication Number: US-2011074066-A1

Title: Methods of demolding building products from a mold

Description:
TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION 
     The present invention relates to an apparatus useful for removing, or demolding, manufactured simulated building products from a mold. 
     BACKGROUND OF THE INVENTION 
     Simulated stone molded building products include simulated stone veneers which are used as a lightweight veneer facing on masonry and on metal framed or wood framed construction for architectural aesthetics. The simulated molded building products can be used for exterior applications such as building walls or interior applications such as fireplaces. Simulated building products include capstones, hearthstones, keystones, trim stones and the like. The simulated stone building products are usually lower in cost than the natural stones that they replace. CULTURED STONE® products are simulated stone products manufactured by the Cultured Stone Corporation, a division of Owens Corning, Napa, Calif. The CULTURED STONE® product line includes hundreds of designs of precast stone veneers and architectural trim products that replicate an extensive variety of textures, sizes, shapes and colors of natural stone and non-natural stones (including but not limited to bricks or brick veneer), i.e., colors that do no occur in nature. The simulated stone products are manufactured using molds taken from natural stones. The molds generally include a flexible layer having at least one mold cavity that is filled with a castable material. The castable material is cured, or set, and formed into the simulated building product. 
     The building product removal process, however, can be especially difficult and often expensive due to the amount of manual labor needed to remove the simulated building product from the mold without damaging either the building product or the mold. In situations where the mold has more than one type of shaped mold cavity it is especially difficult to efficiently and safely remove each type of simulated building product from the mold. 
     SUMMARY OF THE INVENTION 
     A demolding apparatus for removing a molded building product from a mold has a conveyor assembly which advances the mold in a machine direction. The conveyor assembly has a gripping mechanism which holds a leading edge of the mold in a cross-machine direction as the mold is advanced in the machine direction. A dislodging mechanism removes the molded building product from the mold as the mold is moved in the machine direction. 
     In another aspect, a removal mechanism contacts a dislodged portion of the molded building product and applies a dislodging force to the dislodged molded building product from the mold. 
     Various advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic illustration showing a side elevational view, partially in phantom, of one embodiment of a demolding apparatus. 
         FIG. 2  is a schematic illustration showing a front elevational view of the demolding apparatus shown in  FIG. 1 . 
         FIG. 3  is a schematic illustration showing a top plan view of the demolding apparatus shown in  FIG. 1 . 
         FIG. 4  is a schematic illustration in elevation of a conveyor system and a removal assembly of the demolding apparatus shown in  FIG. 1 . 
         FIGS. 5A ,  5 B and  5 C are cross-sectional schematic illustrations of a dislodging mechanism having an engagement member at various stages of dislodging a molded building product from a mold. 
         FIG. 5D  is a schematic perspective illustration of the embodiment of the engagement member shown in  FIGS. 5A-5C . 
         FIG. 6  is a cross-sectional illustration of another embodiment of a removal assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The demolding apparatus  10  shown in the figures herein is useful in the removal of molded building products  30  from a mold  12 . The mold  12  includes one or more mold cavities  20 . For ease of illustration, only one mold  12  and one mold cavity  20  will be discussed in detail; however, it is to be understood that the mold  12  typically contains a plurality of mold cavities  20  that are arranged therein in an efficient pattern. 
       FIGS. 1 ,  2  and  3  show the demolding apparatus  10  which generally includes a mold conveyor assembly  50 , an ejection member, such as an ejection roll  72 , and a removal member, such as a removal roll  92 .  FIG. 1  also schematically shows the demolding apparatus  10  having several molds that are at different stages therein: gripping an inverted mold  12   a , demolding an inverted mold  12   b , and releasing an empty mold  12   c , shown in phantom. 
     The mold  12  has a front side  22  and a back side  24 . The mold  12  also has a leading edge  26  and a trailing edge  28 . Each mold cavity  20  has the imprinted shape of a corresponding natural molded building product  30 . 
     The molded building product  30  has a textured front face  32 , textured side faces  34 , and an untextured back face  36 . For ease of further discussion herein, the molded building product  30  will also be referred to as having a first, dislodged end, or portion,  37  which is oriented toward the leading edge  26 . The molded building product  30  also has a second, trailing end  38 . 
     In certain embodiments, the demolding apparatus  10  includes a frame assembly  40  which supports a platform support member  42  over which the mold  12  is conveyed. In certain embodiments, the platform support member  42  can be a conveyor-type device which assists in moving the mold  12  in the machine direction, shown by the arrow MD in  FIG. 1 . In other embodiments, the platform support member  42  can be a stationary device over which the mold  12  is moved. The platform support member  42  can be made of any suitable material that will support the mold  12 . In certain embodiments, the platform support member  42  can be a perforated material which allows any loose material from the molded building product  30  to pass therethrough. 
     In another embodiment, the platform support member  42  can be made of highly wear resistant ceramic tile. 
     As the mold  12  is moved onto the platform support member  42 , the mold  12  is engaged by the mold conveyor assembly  50 . The mold conveyor assembly  50  includes one or more gripping mechanisms  52 , and a drive member  56  operatively connected to a pair of parallel spaced apart conveyors  58   a  and  58   b , as best seen in  FIGS. 2 and 3 . 
     In an alternative embodiment (not shown), the mold  12  comprises a continuous belt conveyed through the demolding device, and the grippers and all hardware associated with discrete molds are not required. In such an embodiment, the belt may be significantly longer, to enable an operation where the concrete is poured into the molds, cured, then conveyed within the continuous belt to the device described herein for pulling, or the belt may be poured, cured, then transported to the demolding apparatus. In such an embodiment, the gripping mechanism shall be construed to comprise the belt and the associated hardware configured to move the belt as the mold is advanced in the machine direction. 
     The first and second conveyors  58   a  and  58   b  can have more than one gripping mechanism  52  disposed along their linear lengths so that more than one mold  12  can be advanced through the demolding apparatus  10  at the same time. For ease of illustration herein, only one gripping mechanism  52  will be discussed in detail. 
     The gripping mechanism  52  applies a gripping force along the leading edge  26  of the mold  12 . The gripping mechanism  52  holds the leading edge  26  in a secure manner as is pulls the mold  12  through the demolding assembly  10 . The gripping mechanism  52  substantially prevents the leading edge  26  from rotating so that it is no to longer aligned with the machine as the mold  12  is being advanced in the machine direction. 
     The cross-machine gripping of the leading edge  26  by the gripping mechanism  52  allows for a substantially steady and uniform machine direction pressure exerted on the edge  26  of the mold  12 . The cross-machine gripping mechanism  52  compensates for any variations that may be present in the thickness of the leading edge  26 . The cross-machine gripping of the leading edge  26  overcomes previous problems with pulling molds where the continued and repeated use of the building product molds often caused a build-up of castable material and/or building product debris to accumulate on the edges of the mold  12 . The gripping force applied by the gripping mechanism  52  across the leading edge  26  overcomes any of these difficulties and allows the mold  12  to be evenly advanced through the demolding assembly  10 , as further explained below. 
     As best seen in  FIG. 3 , the gripping mechanism  52  has opposing spaced apart first and second mounting blocks  53   a  and  53   b  and a cross-machine gripping member  54  which extends between the first and second mounting blocks  53   a  and  53   b . The first mounting block  53   a  is secured to the first conveyor  58   a  and the second mounting block  53   b  is secured to the second conveyor  58   b  to secure the gripping member  54  in the cross-machine direction. As shown in  FIG. 3 , the gripping member  54  is configured to maintain the mold  12  in the space between the conveyors  58   a ,  58   b  as the mold  12  is advanced. 
     In certain embodiments, the gripping member  54  can be any suitable clamp-like device that substantially secures the mold  12  to the conveyors  58   a  and  58   b . It is within the contemplated scope of the present invention, however, that the gripping member  54  can include other types of gripping members which readily open and close on the leading edge  26  of the mold  12 , or otherwise grip the leading edge  26 . For example, other useful gripping members can include, but are not limited to actuator levers, camming mechanisms, opposing leaf springs, cross-machine bars embedded in the leading edge of the mold, magnetically disposed bars, and the like. 
     The drive motor  56  advances the pair of oppositely disposed conveyors  58   a  and  58   b  and the mold  12 , which is held by the gripping mechanism  52 , over an advancing assembly  60  which defines a conveyor path. One configuration of the advancing assembly  60  is schematically shown in  FIG. 4  where each of the pair of conveyors  58   a  and  58   b  forms a continuous path over the advancing assembly  60 . The advancing portions of the conveyors  58   a ,  58   b  travel over first rolls  61   a ,  61   b  that are adjacent to the drive motor  56 . The conveyors  58   a  and  58   b  are advanced in the machine direction toward the ejection roll  72  and around rolls  62   a ,  62   b . The conveyors  58   a  and  58   b  then return in a reverse machine direction over one or more returning rolls  63   a ,  63   b ,  64   a ,  64   b ,  65   a ,  65   b . It is to be understood that the conveyor path can be arranged in different configurations. 
     The conveyor assembly  50  and the advancing assembly  60  are operated together to advance the leading edge  26  of the inverted mold  12  toward the ejection roll  72 . In the embodiment shown, the ejection roll  72  advances the mold  12  around a curved path. In certain embodiments, it has been found especially useful to invert or flex the mold  12  at an angle of at least about 100° and preferably about 160° to about 180° from the horizontal planar position in order to begin to dislodge the molded building product  30  from the mold  12 . 
     In the embodiment shown, the ejection roll  72  is rotated about its longitudinal axis  74 . In certain embodiments, the ejection roll  72  can include a resilient covering  76 . In certain embodiments, the resilient covering  76  can comprise a soft foam material. The resilient covering  76  is at least partially deformed as the mold  12  is pulled around the ejection roll  72 . The resilient covering  76  also allows the demolding apparatus  10  to accommodate different thicknesses of molded building product  30 . Also, the resilient covering  76  protects or cushions the molded building product  30  as the molded building product  30  is being dislodged from the mold cavity  20 , thus reducing breakage of the molded building product  30 . 
     The diameter of the ejection roll  72  is determined, in part, by the size and shape of the molded building product  30  being demolded. The ejection roll  72  can be operatively mounted in the demolding apparatus  10  such that one ejection roll  72  can be replaced with a different ejection member having a different diameter in order to accommodate molds having different sized and shaped molded building products  30 . For, example, in certain embodiments, the ejection roll  72  has a diameter of about 4 inches or less, while in other examples, the diameter can be greater or less than 4 inches. 
     The ejection roll  72  can be connected to a driving member such as a motor  78  in order to aid in advancing the mold  12  around the ejection roll  72 . 
     Referring now in particular to the schematic illustration in  FIGS. 5A-5D , the leading edge  26  of the mold  12  is advanced around the ejection roll  72 . The back face  24  of the mold  12  engages the ejection roll  72 . The advancing mold  12  generally flexes and at least somewhat conforms to the shape of the ejection roll  72 . The molded building product  30 , however, due to its rigid nature, is not flexed. The distortion, or flexing, of the mold  12  around the ejection roll  72  initially forces at least a portion  37  of the molded building product  30  to be dislodged from the mold cavity  20 . 
     In embodiments having the resilient covering  76  on the ejection roll  72 , the molded building product  30  pushes against the covering  76 . The covering  76  allows the mold  12  to be stretched or distorted sufficiently to at least partially dislodge the molded building product  30  without allowing the molded building product  30  to damage or tear the mold  12  itself. 
     As the dislodged portion  37  of the molded building product  30  is ejected from the mold cavity  20 , the molded building product  30  is forced into a somewhat tangential relationship with respect to the ejection roll  72 . The molded building product  30 , however, continues to be advanced in the machine direction. In certain embodiments, the molded building product  30  is also somewhat rotated in a generally upward direction. At least momentarily, the molded building product  30  remains lodged in the mold  12  due, at least in part, to the continued engagement of the second or trailing end  38  of the molded building product  30  within the mold cavity  20 . 
     As the mold  12  advances around the ejection roll  72 , the mold  12  is peeled away from the molded building product  30 . The mold  12  is continued to be forced against the ejection roll  72 . In certain embodiments, the mold  12  is flexible and elastomeric such that the mold  12  is at least partially flattened against the ejection roll  72 . The ejection roll  72 , however, has a sufficient stiffness such that the molded building product  30  is at least partially forced from the mold cavity  20 . 
     The leading edge  26  of the mold  12  is moved in a forward machine direction, then upward and, finally backward in a return machine direction around the ejection roll  72 . Meanwhile, the molded building product  30  continues in the forward machine direction and the first, or dislodging portion  37 , is at least partially pulled from the mold cavity  20 . 
     The leading edge  26  of the mold  12  is then advanced in the return machine direction. The molded building product  30  continues in a generally straight, or tangential, direction with respect to the ejection roll  72  due to the rigid shape of the molded building product  30 . However, there may be a tendency for the molded building product  30  to ride upward to follow the mold  12 . 
     The ejection roll  72  also exerts a force on the back  24  of the mold  12  as the mold  12  is advanced around the ejection roll  72 . That is, the mold cavity  20  experiences the necking, or Poisson, effect where the mold  12  undergoes a longitudinal expansion which, in turn, causes the mold  12  to somewhat contract in the lateral direction. 
     The mold  12  is also somewhat flattened against the ejection roll  72 . While the flattening of the mold  12  against the ejection roll  72  somewhat overcomes this Poisson effect, both the Poisson effect and the adhesive force of the mold  12  against the molded building product  30  often cause the molded building product  30  to remain at least partially lodged in the mold cavity  20 . 
     As the molded building product  30  continues in the machine direction, the dislodged portion  37  is contacted by the removal roll  92 . The removal roll  92  is rotated about its longitudinal axis  94  by a drive member  95  in a counterclockwise direction, as viewed in  FIG. 5A . In certain embodiments, the removal roll  92  can include one or more flexible engagement members  96  circumferentially mounted on the removal roll  92 . The removal roll  92  is operatively engaged to apply a dislodging force to the dislodged portion  37  of the molded building product  30 . 
     The removal roll  92  exerts a generally downward force on at least the dislodged portion  37  of the molded building product  30 . In embodiments where the engagements member  96  are present, the advancing molded building product  30  pushes against the engagement members  96 , thus gradually temporarily deforming them. Simultaneously, however, the engagement members  96  cause a gradually increasing amount of dislodging force to be exerted in a direction counter to the tangential upward movement of the molded building product  30 . The removal roll  92  exerts a sufficient force to completely dislodge the molded building product  30  from the mold cavity  20 . The molded building product  30  is then completely dislodged from the mold cavity  20  without allowing the molded building product  30  to damage or tear the mold  12 . 
     Referring again to  FIGS. 1-4 , in certain embodiments, the removal roll  92  can include a positioning assembly  98  for moving the removal roll  92  into a desired position adjacent the ejection roll  72 , as shown by the arrows A and B in  FIG. 4 . The removal roll  92  can also be movably positioned relative to the conveyor assembly  50  for accommodating different shaped molds, as shown by arrows A and B in  FIG. 5B . In certain embodiments, the removal roll  92  and the ejection roll  72  are mounted in a parallel, yet separate horizontal planar relationship, as shown in  FIG. 5B . In other embodiments, the removal roll  92  is mounted in both a horizontal planar and parallel relationship to the ejection roll  72 , as shown in  FIG. 5A . 
     Also, in certain embodiments, the removal roll  92  can be mounted in a somewhat vertical reciprocating manner to apply an intermittent dislodging force to the dislodged portion  37  of the molded building product  30 . The removal roll  92  can be repeatedly and rapidly reciprocated in the direction of arrow A, as shown in  FIG. 4 . 
     Referring again to the schematic illustrations in  FIGS. 5A-5C , the removal roll  92  contacts dislodged portion  37  of the molded building product  30  and forces the molded building product  30  in a downward direction away from the mold  12 . The dislodging force is supplied to the molded building product  30  at the points where the molded building product  30  disengages from the mold  12 . Since the molded building product  30  is also simultaneously being advanced in the machine direction, dislodging forces are also being applied to counter the adhesive force being applied by the mold  12  on the molded building product  30 . The removal roll  92  forces the molded building product  30  from the mold  12 , thereby overcoming both the Poisson effect and the adhesive effect. 
     In the embodiment shown, the ejection roll  72  and the removal roll  92  are both rotated in a counterclockwise direction, as shown in the drawings. As the removal roll  92  continues to rotate in the counterclockwise direction, the removal roll  92  pushes the molded building product  30  both in a downward direction, and then as the removal roll  92  continues to engage the dislodged portion  37 , in the forward machine direction. 
     In certain embodiments, as shown in  FIGS. 5A-5C , the removal roll  92  further includes the engagement member  96  which is brought into contact with the dislodged portion  37 . The engagement member  96  exerts the dislodging force in a generally downward direction on the dislodged portion  37  of the molded building product  30 . 
     As shown in  FIG. 5D , the engagement member  96  can include an array of contacting members  100  longitudinally aligned on the removal roll  92  in the cross-machine direction. The contacting members  100  are configured to exert downward dislodging forces to the dislodged portion  37  of the molded building product  30 . 
     In the embodiment shown in  FIG. 5D , the engagement member  96  includes one or more rows  102  of the contacting members  100 . Also, in certain embodiments, the rows  102  of contacting members  100  comprise tangentially disposed rows of independently disposed flaps  104 . In a further alternative embodiment, such flaps comprise brushes. While the embodiment shown in  FIGS. 5A-5D  is illustrated as having four rows  102 , in other embodiments, fewer or greater numbers of rows  102  can be used to exert the desired dislodging forces on the molded building product  30 . 
     In the embodiment in  FIGS. 5A-5C , the flaps  104  are disposed along an outer circumference of the removal roll  92  and extend in a tangential manner to the outer circumference thereof. The flaps  104  have a sufficient stiffness to provide the necessary dislodging forces onto the dislodged portion  37  of the molded building product  30 . The flaps  104  also have a desired flexibility so that each flap  104  can come into contact with individual molded building products  30  in the mold  12 . 
     As the removal roll  92  is rotated, the flaps  104  come into contact with the advancing molded building product  30 . The removal roll  92  is optionally rotated at a desired speed such that one or more rows  102  of flaps  104  contacts the dislodged portion  37  of the advancing molded building product  30 . Each row  102  of flaps  104  then exerts the desired dislodging forces against the molded building product  30 . 
     When the removal roll  92  is rotated at certain speeds, the tangentially advancing rows  102  of flaps  104  continue to contact the molded building product  30  such that each row  102  of flaps  104  provides intermittent dislodging forces against the dislodged portion  37  of the molded building product  30 . 
     The adjacent flaps  104  allow individual dislodging forces applied on the desired dislodged portions  37  of the molded building products  30 . In certain embodiments, the flaps  104  have a desired longitudinal width  106  so that adjacent flaps  104  within the same row  102  can contact different molded building products  30 , or portions of one molded building product  30 . For example, when broad, flat molded building products are oriented in the cross-machine direction, a first flap  104  can contact a corner of the molded building product  30  while the adjacent, second flap  104  can contact an adjacent portion of the molded building product  30 . Likewise, an adjacent, third flap  104  can contact an opposing dislodging corner of an adjacent, similarly situated molded building product  30  in the mold  12 . In another example, (not shown) long and narrow molded building products  30  (often having different lengths) are oriented in the machine direction in the mold  12  such that the narrow end of the molded building product  30  is advanced toward the removal roll  92 . As such a mold approaches the removal roll  92 , a first flap  104  can contact the leading portions  37  of more than one first narrow molded building product while the adjacent second flap  104  can contact still other molded building products. In such molds  12  that contain long and narrow molded building products  30 , the repeated dislodging forces being applied to the advancing and dislodging portion  37  of the molded building product  30  provides the necessary force to completely dislodge the molded building product  30  without damaging either the molded building product  30  or the mold  12 . 
     As the molded building product  30  continues to be advanced in the machine direction, the second end, or trailing portion,  38  of the molded building product  30  then is also dislodged from the mold  12 . 
     Thus, combined forces are applied to the molded building product  30 : i) the tangentially directed dislodging force of the flaps  104  against the dislodged portion  37 ; ii) the advancing machine direction force of the molded building product  30  against the flaps  104 ; iii) the pushing force of the ejection roll  72  against the back  24  of the mold  12 ; and, iv) the force on the trailing end  38  of the molded building product  30  against the platform support member  42  in a direction perpendicular to the machine and cross-machine directions. The combined forces work to pull (i.e., dislodge) the molded building product  30  from the mold  12 . 
       FIG. 6  shows another embodiment of an engagement member  110  which comprises a resilient or elastomeric member such as a soft foam material. The resilient engagement member  110  is at least partially deformed as the dislodging portion  37  comes into contact with the resilient engagement member  110 . The resilient engagement member  110  also allows the demolding apparatus  10  to be able to accommodate different thicknesses of molded building products  30 . Also, the resilient engagement member  110  protects or cushions the molded building product  30  as the molded building product  30  is being dislodged from the mold cavity  20 , thus reducing breakage of the molded building product  30 . The diameter of the resilient engagement member  110  is determined, in part, by the size and shape of the molded building product  30  being demolded. Also, in certain embodiments, the resilient engagement member  110  can include hollow spaces  112  to provide further resiliency. 
     The demolding apparatus  10  increases the manufacturing capacity for simulated molded building products. The demolding apparatus  10  also has the capacity to process molds that have a greater square footage of molded building products per mold than previous molds. The demolding of the simulated molded building products using the demolding apparatus  10  and the method described herein also decreases the demolding cycle time and decreases the scrap and breakage rate. The demolding apparatus also provides a cleaning action to the molds. 
     While the invention has been described with reference to a preferred embodiment, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the essential scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.