Patent Publication Number: US-2021187605-A1

Title: Rotating indexing apparatus for conveying sand molds

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application, Ser. No. 62/950,452, filed on Dec. 19, 2019. The co-pending Provisional Application is hereby incorporated by reference herein in its entirety and is made a part hereof, including but not limited to those portions which specifically appear hereinafter. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention is directed to conveyors for feeding sand molds for metal casting from one machine, such as a forming machine, to a second machine, such as a metal pouring station. The invention provides a method and apparatus for transferring prepared sand molds using walking beam-type mold conveyors. 
     Discussion of Related Art 
     Molded metal castings are commonly manufactured at foundries through a matchplate molding technique which employs green sand molds comprised of prepared sand and additives which are compressed around cope and drag patterns mounted on opposite sides of a matchplate. The sand mold is thus formed in upper and lower matching portions, an upper cope mold, and a lower drag mold. The cope mold is formed in a separate cope flask which is filled with prepared sand and compacted onto the matchplate. The matchplate is then removed leaving an indentation in the cope mold of the desired shape for the upper portion of the casting. Simultaneously, the drag mold is formed in a separate drag flask. Usually the matchplate is in the form of a planar member with the pattern for the cope mold on one side and the pattern for the drag mold on the other. After the cope and drag molds have been formed, they are placed together to form a unitary mold having an interior cavity of the desired shape. The cavity can then be filled with molten metal through an inlet or “sprue” provided in the cope mold to create the desired casting. Such a system is disclosed in U.S. Pat. No. 5,022,212, issued to Hunter, herein incorporated by reference. 
     As with many volume sensitive production operations, manufacturers are required to automate the manufacturing process in order to remain competitive. Foundries engaging in the casting of metal objects through the use of green sand molds are not immune to this reality. It is common in today&#39;s marketplace, for the machine which produces the sand molds to be connected to a machine which fills the sand mold with molten metal, which in turn is connected to a machine for cooling the molten metal into a solid casting, which in turn is connected to a machine for removing the sand mold and revealing the casting for harvest. Such a system is disclosed in U.S. Pat. No. 4,589,467, issued to Hunter, herein incorporated by reference. 
     In the aforementioned &#39;467 Patent, the sand molds are manufactured and communicated along a linear conveyor to a circular, rotating, or “carousel” conveyor. Molten metal is introduced into the molds at one location on the carousel and the molten metal is then allowed to cool within the sand mold as the carousel rotates. The carousel is provided with both an outer diameter track and an inner diameter track which provides for additional cooling of the metal, and which increase the throughput of the machine. 
     U.S. Pat. 7,637,303, issued to Hunter, herein incorporated by reference, discloses a walking beam-type mold conveyor. There is a continuing need for an improved conveyor system for transporting sand molds from the machine that produces the sand mold to, for example, the carousel conveyor, particularly for machines not originally designed to be used together. 
     SUMMARY OF THE INVENTION 
     A general object of the invention is to provide a mold conveyor that feeds molds from an origin, e.g., a mold forming device, to a destination, e.g., a metal pouring station. The general object of the invention can be attained, at least in part, through a method for conveying a sand mold with an accumulating conveyor. The accumulating conveyor includes one or more walking-beam-type conveyors that includes a transfer rail movable with respect to at least one stationary fixed rail. 
     In embodiments of this invention, the method and apparatus for conveying sand molds begins by depositing a first sand mold on a transfer conveyor, such as from a sand mold forming device in combination with the first transfer conveyor. The transfer conveyor includes two outboard rails and a central transfer rail movable between the two outboard rails. The first sand mold moves along the first transfer conveyor in a first direction and is placed on a transfer station at a downstream end of the first transfer conveyor. The transfer station is likewise at an upstream end of a second transfer conveyor, which similarly includes two outboard rails and a central transfer rail movable between the two outboard rails. 
     In embodiments of this invention, the transfer station includes an indexing apparatus that can be used to handle a mold to transfer, move and/or otherwise position a mold, such as a sand mold that is already prepared for molding metal and/or another suitable molding material. According to some embodiments of this invention, a mold structure can be transported and/or otherwise moved to a particular or a preferred position and then the mold structure can be moved by rotating and/or pivoting the mold structure, for example, by moving and/or otherwise positioning the mold structure approximately 90 degrees which is approximately a perpendicular position or movement. The indexing apparatus also be included anywhere along a conveyor for use to reorient the mold on the conveyor, if needed. 
     The invention includes a transfer station apparatus for conveying sand molds with two resting pads configured to receive a sand mold thereon, the resting pads spaced apart and rotatable from a first angular position to a second angular position. The first angular position is aligned with a first transfer conveyor for the sand mold, and the second angular position is aligned with a second transfer conveyor for the sand mold. The apparatus can include a rail channel disposed between the resting pads, configured to rotate and alternatively receive a transfer rail of each of a first transfer conveyor and a second transfer conveyor. 
     In embodiments of this invention, the transfer station is moved and/or otherwise positioned so that the mold structure rotates and/or otherwise pivots about a relative angle that is less than or more than 90 degrees if needed. In some embodiments of this invention, a motor, a driver and/or any other moving device can be used to move the mold structure in any suitable direction, for example, a rotational direction with respect to the mold structure itself, with respect to a base structure structurally supporting the mold structure and/or with respect to another suitable structure. 
     In some embodiments of this invention, the base structure is secured, adjustably fixed and/or otherwise secured to a frame, a support and/or any other suitable structure that sufficiently supports and/or otherwise holds the mold structure and allows it to move with respect to itself and/or another structure. 
     The invention further includes an apparatus for conveying sand molds with a first transfer conveyor oriented in a first direction and a rotating junction transfer station disposed at an end of the first transfer conveyor. The junction transfer station includes two resting pads configured to hold a sand mold, wherein a transfer rail of the first transfer conveyor is movable between the spaced apart resting pads of the junction transfer station to deposit the sand mold. The junction transfer station can include a roller or other support surface adapted to receive and/or support the first transfer rail. 
     The apparatus desirably includes a second transfer conveyor in conveying combination with the first transfer conveyor and oriented in a second direction that is different than the first direction. The second transfer conveyor also includes at least one transfer rail movable with respect to at least one fixed rail, wherein the rotating junction transfer station is disposed between the first and second transfer conveyors. The central transfer rail of each of the first and second transfer conveyors is also movable between the spaced apart resting pads after rotation of the rotating junction transfer station. 
     In embodiments of this invention, one of the two spaced apart resting pads, which is disposed toward the first and second transfer conveyors during rotation, has truncated or otherwise shaped outer corners to promote rotation. This allows the rotating apparatus to be placed closer to the conveyors, without over limiting resting pad size. 
     In embodiments of this invention, the rotating junction transfer station comprises a sensor mechanism. The sensor mechanism can sense the presence or absence of the sand mold on the resting pads to initiate rotation. The sensor can be combined with other sensors of the conveyor system to assist in moving the sand molds on the conveyors. 
     The invention further includes a method for conveying a sand mold. The method includes moving the sand mold in a first direction with a first transfer conveyor via a transfer rail reciprocating with respect to at least one fixed rail, moving the sand mold onto resting pads of a junction transfer station disposed at an end of the first transfer conveyor, and rotating the resting pads and the sand mold for moving the sand mold in a second direction that is at an angle to the first direction. The invention can further include steps of: lifting the sand mold off the at least one fixed rail with the transfer rail; moving the transfer rail with the lifted sand mold in a downstream direction between the resting pads; lowering the lifted sand mold onto the resting pads; moving the first transfer conveyor transfer rail from between the resting pads; upon the rotating the resting pads, moving a second transfer conveyor transfer rail under the sand mold between the resting pads; and lifting the sand mold off the resting pads with the second transfer conveyor transfer rail. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view of an accumulating mold conveyor according to one embodiment of this invention. 
         FIG. 2  is a side view of an accumulating mold according to one embodiment of this invention. 
         FIGS. 3 and 4  each illustrate accumulating mold conveyor sections according to one embodiment of this invention. 
         FIGS. 5A and 5B  illustrate an accumulating mold conveyor according to one embodiment of this invention. 
         FIGS. 6 and 7  show accumulating mold conveyor sections according to  FIGS. 5A and 5B . 
         FIGS. 8-10  illustrate an indexing mechanism according to one embodiment of this invention. 
         FIGS. 11-14  illustrate an indexing mechanism according to one embodiment of this invention. 
     
    
    
     DEFINITIONS 
     Within the context of this specification, each term or phrase below will include the following meaning or meanings. 
     References herein to “conveying combination” are to be understood to refer to a combination of two elements, such as two conveyors, whereby an item conveyed by one element is transferable to the other element for continued conveyance to the intended destination. 
     References herein to “upstream” and “downstream” are to be understood with reference to directions of travel of molds on a conveyor. “Upstream” refers to a direction toward a place of origin, such as a mold forming device, and “downstream” refers to a direction toward a place of destination. 
     DESCRIPTION OF FIGURES 
     Referring to  FIG. 1 , this invention provides a conveyor assembly, shown as accumulating mold conveyor  20 , for transporting sand molds from a first station  16 , such as a sand mold forming station, to a second station  18 , such as a metal pouring station. 
     Accumulating mold conveyor  20  includes first transport conveyor  22  oriented in a first direction, and second transfer conveyor  24  oriented in a second direction. As will be appreciated, aspects of the invention can be applied to an accumulating conveyor with only one transfer conveyor or more than two. In the embodiment of  FIG. 1 , first and second transfer conveyors  22  and  24  are disposed perpendicular to each other; however, the conveyors of this invention can be disposed at other angles, depending on need. First transfer conveyor  22  has an upstream end  30  that is to be disposed toward first station  16 , and a downstream end  32  opposite the upstream end  30 . Similarly, second transfer conveyor  24  has an upstream end  34  and an opposing downstream end  36 . Sand molds travel along the conveyors of this invention from an upstream end to a downstream end. Downstream end  32  of first transfer conveyor  22  is in conveying communication with upstream end  34  of second transfer conveyor  24 , such that a sand mold is transferred during operation from downstream end  32  of first transfer conveyor  22  to upstream end  34  of second transfer conveyor  24 . 
     First transfer conveyor  22  includes first outboard rail  46  spaced apart from second outboard rail  48 . Outboard rails  46  and  48  can each be formed as a single rail member or from a plurality of smaller individual rail members. A central rail channel  50  is formed between first outboard rail  46  and second outboard rail  48 . Central transfer rail  52  is disposed within central rail channel  50 , and is movable therein and between the two fixed outboard rails  46  and  48 . Second transfer conveyor  24  includes components identical or at least similar to first transfer conveyor  22 . These components are described with reference to first transfer conveyor  22 , and identified by element reference numbers associated with a prime (′). 
     A pusher station  55  is optionally disposed at the end  36  of the second transfer conveyor  24 . The pusher station  55  includes a pusher  40  that moves each mold from the conveyor  24  to the second station  18 . As shown in  FIG. 1 , each of the stations  16  and  18  are located laterally relative to the conveyor ends  30  and  36 , respectively. The pusher moves in a direction perpendicular to the conveyance direction of the second transfer conveyor  22  to push the mold onto the second station  18 . An optional lift mechanism with a lift plate or platform  45  can be used if the second station  18  is at a different height from the first station  16 , such as shown in  FIG. 2 . 
     The accumulating mold conveyor of this invention is not limited to the configuration and number of fixed and moveable rails shown in  FIG. 1 . For example, the center rail(s) can be fixed in place and not moveable, with two or more outboard rails moveable with respect to the fixed center rail(s). Also, in one embodiment of the invention, two moveable transfer rails are disposed on either side of a fixed center rail, and each of the moveable transfer rails is between the center rail and a further fixed outboard rail (e.g., five total rails). 
       FIG. 2  is a side view of accumulating mold conveyor  20  showing molds  25  thereon. As shown in  FIG. 2 , the second station  18  has a receiving surface that is higher than the mold conveyor  20 . The height of the mold conveyor  20  is chosen due to the height of first station  16 , and in  FIG. 2 , the pusher station  55  is incorporated into or with an optional lift mechanism, forming a lift and transfer station  55 . As will be appreciated, the lift station could additionally or alternatively be incorporated elsewhere along the conveyor, such as at the end near the first station or at a junction of two or more conveyors, depending on need. 
     As shown in  FIG. 3 , the central transfer rail  52  is a reciprocating rail that includes a rail frame  54 , including crossbars  53 , disposed upon a plurality of rollers  56 . Each transfer conveyor includes at least one pressurized fluid piston  58 , e.g., a hydraulic piston, having a moveable piston arm  60  connected to frame  54  by connector  62 . Piston arm  60 , and thus frame  54  and central transfer rail  52 , is movable between an upstream position and a downstream position. In embodiments of this invention, the central transfer rail is movable between three positions, a central position, an upstream position, and a downstream position. 
     A plurality of sand mold carrier plates  70  is disposed along the frame  54 . Each of carrier plates  70  is attached to the rail frame  54  by one of a plurality of pressurized fluid lift mechanisms  72 , e.g., a pneumatically actuated piston. Each of pressurized fluid lift mechanisms  72  is adapted to lift a corresponding one of carrier plates  70 , and a sand mold thereon, to a lifted position above or higher than the outboard rails  46  and  48 , and then to lower the corresponding one of carrier plates  70  to lowered position. In the lowered position, sand molds  25  are disposed on outboard rails  46  and  48 . In the lifted position, sand molds  25  are moved to, and then lowered onto, a downstream position on outboard rails  46  and  48 . 
     The lifting distance of the sand molds  25  can vary depending on need. In one embodiment of this invention, the sand molds  25  are lifted less than an inch above the outboard rails  46  and  48 , and more desirably about 1/16 th  of an inch. In another embodiment, the sand molds are not actually lifted off the outboard rails, but the carrier plates place upward pressure on the sand molds to reduce friction and allow the sand molds to more easily slide along the outboard rails. 
     Sand molds  25  are moved along first transfer conveyor  22  by lifting a sand mold  25  off outboard rails  46  and  48  at a first of resting positions with a corresponding one of carrier plates  70 , moving the sand mold in a downstream direction with central transfer rail  52  to dispose sand mold  25  over a second of resting positions  80 , and lowering sand mold  25  onto outboard rails  46  and  48  at the second of resting positions  80 . Central transfer rail  52  then moves back to the first position, and the process repeats to incrementally move, or “walk,” sand mold  25  in a downstream direction on first transfer conveyor  22 . 
     Referring to  FIGS. 1 and 2 , lateral entry of the molds  25  onto the conveyor  20  provides additional issues over colinear end entry. Moving the molds from the side can result in a lower leading edge of the mold catching on the rails, particularly the outboard rail on the far side from the entry point. This is due to a lower position of the central rail between the outboard rails. Embodiments of this invention include an optional adjustment mechanism for the central rail, to lift the central rail even with the outboard rails, at least at the entry position. 
       FIG. 3  shows an adjustment mechanism  100  in combination with the first transfer rail  52 . The mechanism includes a leveling cylinder  102  on the conveyor frame  35  that provides vertical movement (or perpendicular to the conveying direction) of the end of the first transfer rail  52 . The cylinder  102 , connected by plate  105  to crossbars  53 , raises the rail frame  54  to level a first pad  70  with the corresponding outboard rail  48 . The frame  54  may be lifted off rollers  56 , and then lowered again after the mold  25  is in the conveying position on the conveyor  20 . 
     A plurality of optional sensor mechanisms can be disposed along each transfer conveyor. Each of the plurality of sensor mechanisms is desirably disposed in sensing combination with one of the resting positions. Sensor mechanisms detect the presence of sand molds along the transfer conveyor, and can be used to actuate lifting of a corresponding carrier plate when a sand mold is disposed above the corresponding carrier plate. Thus, in one embodiment of this invention, a carrier plate is not lifted unless a sand mold is present above. Various and alternative sensor mechanisms are available for the use in the accumulating mold conveyor of this invention, such as, without limitation, motion sensors using visible or infrared light or weight sensors disposed beneath outboard rails. 
     Referring to  FIGS. 1 and 3 , accumulating mold conveyor  20  includes first junction transfer station  86  disposed between downstream end  32  of first transfer conveyor  22  and upstream end  34  of second transfer conveyor  24 . Junction transfer station  86  includes an indexing unit  200 . When the central transfer rail  52  of first transfer conveyor  22  is moved out from first junction transfer station  86 , the indexing apparatus rotates to receive the central transfer rail  52 ′ of second transfer conveyor  24 . When the rotation frame  202  and pads  88  of the first junction transfer station  86  are rotated relative to base  204 , central transfer rail  52 ′ of second transfer conveyor is able to move into the indexing apparatus and lift sand mold  25  off resting pads  88 , thereby perpendicularly transferring sand mold  25  to second transfer conveyor  24 . The configuration of the indexing unit  200 , and resting pad(s)  88  will depend on, and desirably coordinate with, the configuration of the accumulating conveyor and/or transfer rail(s). The indexing unit  200  can include a sensor  214  for determining that a sand mold is placed thereon or removed therefrom, such as for initiating rotation between the two (or more) transfer conveyors. 
     Accumulating mold conveyor  20  includes second junction resting station  90  disposed at the downstream end  36  of second transfer conveyor  24  and within the lifting and transfer station  55 . Second junction resting station  90  can includes four spaced apart resting pads  92  for holding sand molds  25 . Any included lift platform can have an X- or cross-shaped configuration with extensions that fit and lift between pairs of the four pads  92  to lift the mold vertically (perpendicular to the conveying direction) to the pusher  40 . Pusher  40 , which can include a hydraulically activated pusher arm, pushes sand molds  25  off the second junction resting station  90  and onto a receiving surface/platform (e.g., add-on platform  144  of  FIG. 11 ) of the associated station  18 . Further details on the adjustment mechanism and the lifting mechanism, are contained in co-pending application Ser. No. 16/720,307, and herein incorporated by reference. 
     This invention further includes a method for conveying a sand mold. The method of this invention uses an accumulating conveyor, such as described above, including a first transfer conveyor in conveying combination with a second transfer conveyor, each of the first and second transfer conveyors comprising two outboard rails and a central transfer rail movable between the two outboard rails. 
     In one embodiment of this invention, referring to  FIG. 1 , a first sand mold forming machine deposits first sand mold  25  on first transfer conveyor  22 . In one embodiment of this invention, sand mold  25  is placed directly onto first transfer conveyor  22 , without an optional bottom board, such as are known to those skilled in the art. Sand mold  25  moves along first transfer conveyor  22  in a first downstream direction. First transfer conveyor  22  moves sand mold  25  by lifting the sand mold off outboard rails  46  and  48  with central transfer rail  52 , moving central transfer rail  52  and the lifted sand mold  25  in the first downstream direction, and lowering the lifted sand mold  25  onto outboard rails  46  and  48 . The steps for moving first sand mold  25  are repeated until first sand mold  25  is placed by central transfer rail  52  onto first junction transfer station  86 . Upon placing first sand mold  25  onto first junction transfer station  86 , the central transfer rail  52  moves back upstream and out from under sand mold  25 . 
     The transfer station indexing apparatus  200  rotates to allow further downstream mold movement. Central transfer rail  52 ′ of second transfer conveyor  24  then moves under first sand mold  25  to transfer first sand mold  25  to second transfer conveyor  24 . Central transfer rail  52 ′ lifts first sand mold  25  off first junction resting station  86  and moves first sand mold  25  along second transfer conveyor  24  in the manner discussed above for first transfer conveyor  22 , but in a second downstream direction, that is perpendicular to the downstream direction of first transfer conveyor  22 . The steps for moving first sand mold  25  along second transfer conveyor  24  are incrementally repeated until first sand mold  25  is placed by central transfer rail  52  onto second junction resting station  90 . Upon placing first sand mold  25  onto second junction resting station  90 , central transfer rail  52  moves back upstream and out from under first sand mold  25 . 
     As will be appreciated by those skilled in the art following the teachings herein provided, various and alternative sizes, shapes, and configurations are available for the mold accumulating conveyor, transfer conveyors, junction resting/transfer stations, leveling mechanisms, lift mechanisms, pusher mechanism(s), and indexing apparatus of this invention. 
       FIG. 5A  shows an accumulating conveyor  20  according to another embodiment of this invention. The conveyor  20  includes an indexing transfer station  86 , shown with an illustrated circle  201  representing the rotational movement of the indexing unit, as needed along the full 360° circle , but desirably back and forth between the two transfer conveyors (e.g., 90°).  FIG. 5B  shows the indexing apparatus  200  separate from the conveyor  20 .  FIGS. 6 and 7  show side views of the station  86  and indexing apparatus  200 , from two different views. 
     Referring to  FIG. 6 , the indexing apparatus  200  includes resting pads  88  for the mold  25 . The resting pads are mounted parallel on a rotation frame  202 . The rotation frame  202  rotates about base  204  via a rotator  210  connected between the base  204  and rotation frame  202 . As illustrated between  FIGS. 6 and 7 , each transfer rail  52 ,  52 ′ of the conveyor  20  can move between the parallel pads  88 , in the correspondingly rotated position, to move the mold  25  on or off the pads  88 . The corresponding rotated position refers to a position where the pads  88  are parallel to the relevant transfer rail  52  or  52 ′, such that than one of the rails  52  or  52 ′ can move therebetween. When the indexing apparatus  200  rotates, the other of the transfer rails  52  or  52 ′ is then able to move therebetween. 
       FIG. 8  is a partially exploded view of an indexing apparatus  200  according to one embodiment of this invention. The rotation frame  202  includes two resting pads  88 , held elevated to allow transfer rails to move therebetween in rail channel  205 . The frame  202  includes roller brackets  208  for rollers  212  that support transfer rail  52 ,  52 ′ movement in rail channel  205 , such as supporting the undersides of the two sides of rail frame  54 , between the pads  88 . The frame  202  connects to a rotator  210  (representatively illustrated) via bearing plate  220 . The rotator is suitably fixed to the base  204 . 
     The angular rotation of the indexing apparatus  200  can be varied, depending on need. As shown in the illustrated embodiments, the desired rotation is 90°, between the perpendicular transfer conveyors  22  and  24 . As will be appreciated, the rotating indexing apparatus of this invention can be used to provide additional angles between the transfer conveyors  22  and  24 , such as, for example, between 45° and 180°. The indexing apparatus can also be used to rotated between more than two transfer conveyors. As shown in  FIG. 8 , at least one of the resting pads  88  includes truncated corners to facilitate rotation and keep the resting pad from hitting the transfer conveyors  22  and  24  during rotation back and forth over the 90° between the two transfer conveyors  22  and  24 . The truncated corners are shown as two outer corners of the otherwise rectangular resting pad  88  being cut short at an angle across the rectangle corners, but the corners or outer edge of the resting pad can also be curved or otherwise shaped to promote rotation in a desired placement distance from the ends of the transfer conveyors  22  and  24 . For rotation between more than two transfer conveyors, or full 360° rotation, both resting pads, or at least the corners thereof, can need to be shaped as well to allow the larger angular range of rotation. 
       FIGS. 9 and 10  show top and side views of the collar  220 . The bearing plate  220  includes a center opening  222  for a rotator shaft, and keyway slot  224  to allow for proper alignment and/or connection with the frame  202  and/or rotator  210 . 
       FIGS. 11-13  show an assembled indexing apparatus according to one embodiment of this invention. As seen in  FIG. 13 , the bearing plate  222  is connected to the rotator  210  by a cylinder plate  230 , shown also in  FIG. 14 . The rotation frame  202  rotates via, and about an axis of, the rotator  210 . 
     Thus, the invention provides a mold accumulating conveyor that feeds sand molds from multiple sand mold forming machines to a single metal pouring station. The accumulating mold conveyor of this invention improves efficiency of casting by, for example, allowing for a sand mold casting apparatus to continually run, even while one associated sand mold forming machine is offline The invention further provides a more flexible accumulating mold conveyor installation, such as between machine stations of two different manufacturers. The apparatus and method allow for efficient change of direction, moving between accumulating conveyors in angled configurations. 
     It will be appreciated that details of the foregoing embodiments, given for purposes of illustration, are not to be construed as limiting the scope of this invention. Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention, which is defined in the following claims and all equivalents thereto. Further, it is recognized that many embodiments may be conceived that do not achieve all of the advantages of some embodiments, particularly of the preferred embodiments, yet the absence of a particular advantage shall not be construed to necessarily mean that such an embodiment is outside the scope of the present invention.