Abstract:
The mold handler includes a mold closer mechanism that supports the cope and drag halves and effects movement in a closing direction whereby cope and drag halves are moved into mating alignment with one another. The cope and drag halves are with respective alignment structures that mediate the mating alignment of cope and drag halves as they are moved into mating alignment with one another. An air bearing mechanism that supports at least one of said cope and drag halves permits low friction lateral movement in a plane perpendicular to the closing direction to thereby adjust the relative positional relationship of cope and drag by interaction of the alignment structures.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation-in-part of U.S. patent application Ser. No. 13/687,241, entitled “Auto-Closer for Centering and Closing Cope and Drag Sand Mold Halves, filed Nov. 28, 2012. 
    
    
     FIELD 
     The present disclosure relates generally to matchplate sand casting. More particularly, the disclosure relates to an apparatus and method to center and close the cope and drag halves of a sand mold through a technique that allows automated handling of the sand mold halves even after they have been removed from their respective flasks. 
     BACKGROUND 
     This section provides background information related to the present disclosure, which is not necessarily prior art. 
     In matchplate sand mold casting, the mold comprises separate open-face cope and drag halves that are fabricated separately, and then joined together, face-to-face prior to pouring the molten metal. Conventionally, the cope and drag molds are formed using a pair of boxes called flasks which are filled with sand with a removable pattern-half embedded in each. When removed, the pattern-halves leave an impression in the sand of the part to be cast. The cope contains the impression of the upper half of the part and the drag contains the impression of the lower half of the part. The cope also typically includes a pouring cup passageway into which molten metal may be poured, and also a vent to allow air to escape during the pour. To ensure a properly molded part is produced, the cope and drag halves must fit together in perfect alignment. 
     The conventional technique for joining the cope and drag halves involves at least two human workers and a lifting crane. First the cope and drag sand molds are formed in their respective flasks. Then a lifting crane is attached to the cope flask and the structure is lifted and inverted, so that the open-face mold side of the cope is facing downward. Human workers then guide the cope as it is lowered into place on top of the drag. The typical lifting and rotating device is rigidly attached to the outer side walls of the flask by brackets carried on a mechanism journaled for rotation about a horizontal axis. Alignment of cope and drag is accomplished visually and manually. Thus high accuracy in the lifting crane and rotating mechanism is not usually required. 
     With the advent of chemically bonded, no-bake sand, it is now possible with smaller molds (e.g., flask dimensions of about 48 inches or less) to perform the lifting and rotating operation with the flasks removed from the respective cope and drag portions prior to inversion and installing of the cope onto the drag. As before, human operators visually and manually guide the cope into proper position. The lifting and rotating mechanism is different, however, because it must attach directly to the sand sidewalls of the cope. In this application the side walls of the molds are typically slightly tapered or frustum-shaped, having a taper of approximately two degrees to five degrees to allow the mold to be slidably removed from the flask without dismantling the flask and without damaging the mold. 
     Due to this slight inward taper of the sand mold, an articulated joint or knuckle, such as a ball joint or universal joint, is required to allow the attachment plate secured to the mold to change its angle with respect to the rotational axis as 180 degree rotation is effected. However, to ensure that the cope and drag will fit together in perfect alignment, the articulated joint must be manufactured with high precision, as any displacement caused by poor tolerance in the joint will throw the rotated mold out of alignment when it is inverted. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     The auto-closer system and method disclosed here allows sand mold cope and drag halves to be accurately centered and closed onto one another quite quickly and accurately, entirely by automated mechanism, and without the need for human operators to visually guide alignment to ensure proper closing. While the technique is compatible with vision systems and laser-guided technology, these expensive systems are not required to achieve accurate closure. Highly accurate closing is achieved thanks to a unique air bearing structure that cooperates with mating alignment mechanisms to ensure proper alignment. 
     The mold handler includes a mold closer mechanism that supports the cope and drag halves and effects movement in a closing direction whereby cope and drag halves are moved into mating alignment with one another. The cope and drag halves are with respective alignment structures that mediate the mating alignment of cope and drag halves as they are moved into mating alignment with one another. An air bearing mechanism that supports at least one of said cope and drag halves permits low friction lateral movement in a plane perpendicular to the closing direction to thereby adjust the relative positional relationship of cope and drag by interaction of the alignment structures. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  is an end view of the auto-closer mechanism; 
         FIG. 2  is a side view of the auto-closer mechanism; 
         FIG. 3  is a plan view of the auto-closer mechanism with certain components removed to illustrate the inner workings of the centering mechanism; 
         FIG. 4  is a flowchart diagram describing the manner of operation of the auto-closer mechanism; 
         FIG. 5  is a simplified plan view illustrating the operation of the left and right side centering arms of the centering mechanism and also illustrating exemplary cope and drag sand mold halves in process of being assembled; 
         FIG. 6  is a simplified side elevational view showing the manner of operation of the front and rear centering arms; 
         FIG. 7  is a simplified side elevational view showing the operation of the gripping structure; 
         FIG. 8  is an end view of the gripper pad with spring-loaded pins and center-fixed fulcrum; 
         FIG. 9  is a side elevational view of the gripper pad of  FIG. 8 ; 
         FIGS. 10   a  and  10   b  illustrate how the spring-loaded pins operate during rotation of the gripper pad to accommodate the frustum angle of the sand mold, with selected pins having been removed to simplify the illustration; 
         FIG. 11  is a control logic diagram showing how the various moving components of the auto-closer are controlled. 
         FIG. 12  is an end view of the auto-closer which includes an air bearing mold handler assembly; 
         FIG. 13  is an enlarged view showing the air bearing mold handler assembly in greater detail; 
         FIG. 14  is a further enlarged view showing one end of the carrier assembly; 
         FIG. 15  is a side view of the auto-closer with air bearing mold handler, illustrating the device in a first position; 
         FIG. 16  is a side view similar to that of  FIG. 15 , showing the device in a second position; 
         FIG. 17  is a side view similar to that of  FIG. 15 , showing the device in a third position; 
         FIG. 18  is a side view similar to that of  FIG. 15 , showing the device in a fourth position; 
         FIG. 19  is a side view similar to that of  FIG. 15 , showing the device in a fifth position; 
         FIG. 20  illustrates a first embodiment of alignment structure; 
         FIGS. 21   a  and  21   b  illustrate a second embodiment of alignment structure; 
         FIG. 22  illustrates a second embodiment of an air bearing mold handler using a scissors jack to raise the drag into mating alignment with the cope; 
         FIG. 23  is a flow diagram illustrating the first embodiment in use. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Example embodiments will now be described more fully with reference to the accompanying drawings. 
     Referring to  FIGS. 1 and 2 , the auto-closer mechanism has been illustrated generally at  10 . The auto-closer mechanism is built on a support structure frame  12  that is preferably mounted securely to the floor  14 . The auto-closer mechanism includes a positioning station shown generally at  16  onto which a sand mold half is conveyed and then accurately centered using a centering mechanism  18 . In  FIG. 1  an exemplary sand mold half has been illustrated at  20 . As will be more fully described, the positioning station  16  is adapted to receive both cope and drag halves of a sand mold, in alternating succession. The cope half is first conveyed onto the positioning station and then centered, gripped, lifted and rotated 180 degrees. Then the drag half is conveyed onto the positioning station and centered. The cope is then lowered onto the drag to close the mold. 
     The positioning station is preferably constructed in the form of a conveyor platform  22  comprising a belt stretched across two conveyor rollers  24 , as best seen in  FIG. 3 . The conveyor belt is preferably fabricated from a belt material that allows a light dusting of sand to remain on the belt as it operates. This light dusting of sand serves to reduce sliding friction between mold half and belt surface, so that the centering mechanism can position the mold half with reduced force. 
     The centering mechanism  18  comprises a first set of centering arms identified as the left and right side centering arms  26 . These centering arms are perhaps best seen in  FIG. 3 . The arms are hydraulically operated by means of the hydraulically operated rack and pinion mechanism  28 . A hydraulic cylinder  30  applies linear force to one of the centering arms  26  and the rack and pinion gearing transmits this force to the other centering arm, causing the two arms to extend and retract inwardly and outwardly in unison in the directions of the arrows shown. Each of the left and right side centering arms is generally T-shaped, with the pusher bar  27  of each being preferably fabricated from cylindrical bar stock so that the pusher bar will make contact with the sand mold with minimal abrading friction due to the circular cross-section of the pusher bar. 
     The centering mechanism  18  further includes a set of front and rear centering arms  32 , which are perhaps best seen in  FIGS. 1 and 2 . The front and rear centering arms each comprise a pair of spaced apart, axially aligned pusher bars  33 , which are also preferably manufactured using cylindrical bar stock to provide minimal abrading friction when contacting the sand mold. The pusher bars are spaced apart as shown in  FIG. 1  to provide clearance for the gripping structure yet to be discussed. 
     As seen in  FIG. 2 , the front and rear centering arms are driven by a pair of boomerang-shaped cranks, each journaled for rotation about its respective pivot point  35 , with the pusher bars  33  being attached to the opposite ends thereof. The inner ends of the boomerang-shaped cranks are coupled through a slidable journaling mechanism that slides through an elongated channel  3234  which constrains both boomerang cranks to move in unison, but in opposite directions of rotation. A hydraulic cylinder  36 , imparts this rotatory motion by being attached to the cranks as illustrated in  FIG. 2 . As the cylinder  36  extends, the pusher bars  33  rotate about the respective pivot points  35  on arc-shaped trajectories moving towards one another. When the cylinder  36  contracts, the pusher bars move on the reverse trajectory in a generally outward direction from one another. 
     Refer now to  FIGS. 5 and 6  and also to the flowchart of  FIG. 4  for a discussion of how the centering mechanism  18  operates. As illustrated in  FIG. 5 , the conveyor platform  22  serves as the positioning station  16 , where an exemplary sand mold cope  20   c  is disposed. Visible from this view, the cope half  20   c  has a hollowed out mold portion  42  with matchplate alignment structures  40 . Both mold and alignment structures are built into the configuration of the sand mold itself. 
     While there are different mechanisms that may be used to place the mold half onto the positioning station, the illustrated embodiment employs a feed conveyor  38  that is positioned to deliver a mold half onto the conveyor platform  22 . In use, the cope and drag mold halves are alternately delivered to the positioning station. Thus, as illustrated, the mold half on the positioning station in  FIG. 5  is a cope half designated as  20   c , whereas the mold half next to be delivered is a drag half designated  20   d . Note that the drag half  20   d  has been placed on the feed conveyor in a somewhat randomly angled position, to illustrate exemplary “real world” foundry conditions. In other words, the sand mold halves arriving from feed conveyor  38  are not necessarily in square alignment with the centering mechanism when delivered. 
     Referring to  FIG. 4 , the cope portion is delivered at step  100 , with its open side or mold side up. Next, the left and right side centering arms  26  are extended, causing the pusher bars  27  to momentarily contact the mold half along its left and right sides, causing the mold half to move into approximate alignment parallel to the longitudinal dimension of the pusher bars  27 . This step is depicted at  102  in  FIG. 4 . 
     The side centering arms are then retracted as at step  104  and the front and rear centering arms are then rotated inwardly toward one another (slidably guided by elongated channel  34 ) so that their respective pusher bars  33  contact the front and rear surfaces of the mold half, as depicted at step  106 . This is illustrated in  FIG. 6 . This motion causes the mold half to become further aligned, this time so that the front and rear faces of the mold are generally parallel to the longitudinal axes of the pusher bars  33 . This is depicted at step  106 . Then at step  107  the front and rear centering arms are withdrawn, thus momentarily leaving the sand mold half resting on the positioning station without contact from any of the centering mechanisms. 
     Then in step  108  the left and right centering arms are again extended so that they contact and hold the sand mold half in an aligned position between them. This is depicted at step  108 . Unlike the previous centering steps, this time the left and right centering arms remain closed, thus clamping the sand mold in place with respect to the left-right dimension. Next, the front and rear centering arms are likewise rotated into contact with the front and rear faces of the mold, holding those sides in alignment as well. This is illustrated at step  110 . Once step  110  has been reached, the mold half is now centered along first centerline  44  parallel to pusher bars  27  and second centerline  45  parallel to pusher bars  33  and is being securely held by clamping forces from the left and right centering arms and by the front and rear centering arms. 
     The auto-closer mechanism  10  further includes an automated gripping structure that grips, lifts, and rotates the sand mold half, so that it can be mated with a subsequently loaded opposite half. Referring to  FIGS. 1 and 2 , the gripping structure  46  is mounted on a precision-guided sliding frame  48  that is lifted by a pair of lift cylinders  50 . The gripping structure includes a pair of linear rotary actuators  52  that extend longitudinally to grip the sand mold half using a pair of circular gripping pads  54 . The circular nature of the gripping pads is perhaps best seen in  FIG. 8 . 
     For explanation purposes in  FIG. 2 , the linear rotary actuator has been illustrated in both its up position at  52   u  and its down position at  52   d . The linear actuators are driven by hydraulic cylinder  53 . One hydraulic pumping system supplies fluid pressure to both actuators concurrently, so that both actuators operate in synchronism and with equal linear force. The details of the gripper pads  54  will be discussed below. 
     Returning to  FIG. 4 , at step  112  the gripping structure  46  is lowered to the down position ( 52   d  of  FIG. 2 ) as also illustrated in  FIG. 7 . The linear actuators are then extended so that the gripper pads  54  make contact with the side walls of the sand mold half. The linear actuators  52  are supplied with sufficient pressure to drive the gripper pad fingers into the side walls of the sand mold, as will be discussed more fully below. 
     Next, at step  114  the gripping structure is raised by retracting the lift cylinders  50 , causing the mold to be lifted away from the positioning station  16 . Next, as depicted at step  116  the gripping structure is rotated about its rotatory axis until a 180-degree rotation is achieved. This effectively inverts the sand mold half so that it will be in a position to mate with the other half once lowered. 
     In step  118  the second half of the sand mold (open side up) is conveyed onto the positioning station. The same series of centering steps are performed at  120 - 128  as previously described in connection with steps  102 - 110 . These centering steps thus align the second half of the sand mold so that it is in precisely the same position as the first half had been prior to being lifted. Then at step  130  the gripping structure is lowered by extending the lift cylinders  50  until the first half of the sand mold rests on the second half. In doing so, the alignment structures  40  on the respective halves mate with one another to ensure perfect alignment. This is depicted at step  132 . Finally, the closed mold is conveyed as at step  134  away from the positioning station and onto a molten metal pouring station where the cast metal part is formed. 
     In order to ensure tight gripping of the sand mold half being lifted, the gripping cylinders  53  is first supplied with hydraulic fluid under low pressure (nominally 50 PSI) until a certain predefined distance of travel has been achieved. This distance can be determined by calculation by knowing the rate of cylinder travel and thus measuring distance by measuring a predefined travel time. Once the gripping pad is in loose contact with the sides of the sand mold half, a higher pressure is applied (nominally 500 PSI) which causes the gripping structure to more tightly grip the sand mold half. This tight grip is sustained throughout the lifting and rotating process by blocking the valve supplying fluid to the cylinder  53 . In effect, the supply valve is moved to a position where its ports are blocked by the valve, causing the fluid pressure to be retained in the cylinder. Blocking the valve in this fashion may be accomplished by employing a second valve on the exit hose of the main valve, so that fluid pressure cannot be relieved. 
     Referring now to  FIGS. 8 and 9 , the gripper pad configuration will now be discussed in detail. As illustrated in  FIG. 8 , the gripper pad  54  is preferably of circular configuration. A plurality of individual spring-loaded pins  56  are equally distributed around the periphery of the pad and a fixed pin  58  is disposed at the center. The gripping structure with extendable and retractable pins is designed to firmly grip the sand mold and yet permit the mold to be rotated 180 degrees from the initial centering position to the final mating position. 
     Shown in  FIGS. 10   a  and  10   b , it can be seen that the individual spring-loaded pins will change in length automatically by compressing and decompressing the springs so that the pins remain driven into the side walls of the sand mold even as it makes the 180 degree rotation. In the illustration of  FIGS. 10   a  and  10   b , note how the inclined sidewall  60  changes its angle from upwardly inwardly sloping to upwardly outwardly sloping as the rotatory actuator rotates from its initial zero-degree position to its final 180-degree position. The center fixed pin  58 , which may be pointed or rounded, serves as a fulcrum about which the surface of the sand mold can rock, allowing the spring-loaded pins to extend and extract as needed while the fixed center pin keeps the sand mold accurately centered above the positioning station below. 
     While the various moving systems of the auto-closer can be controlled in a variety of ways, including computer-implemented control systems, the basic control scheme depicted in  FIG. 11  is presently preferred, in foundry applications where the control system may be exposed to the heat, dust and potential physical abuse of a real-world foundry floor. To provide a rugged and reliable system for these conditions, the control system uses simple timer switches and limit switches, controlling electric actuators and motors directly or controlling valves which in turn control hydraulic cylinders. 
     Referring to  FIG. 11 , the various moving systems of the auto-closer are depicted vertically along the right side of the Figure at  150 . The conveyor motor  152  drives the conveyor rollers  24  ( FIG. 3 ). A similar conveyor motor (not shown) would drive the feed conveyor  38  that supplies the cope and drag halves to the positioning station. As illustrated, the conveyor motor is controlled by a timer switch  154 . The timer switch is energized concurrently with energizing of the feed conveyor  38  and continues to supply electrical energy to the conveyor motor  152  for a measured time, programmed to allow a cope or drag half to move to generally the center of the positioning station  16 . 
     The left and right centering arms  26  are supplied with mechanical energy from hydraulic cylinder  30 . Movement is controlled by valve  156  which controls the supply of hydraulic fluid into and out from hydraulic cylinder  30 . Valve  156  is controlled using a fluid control mechanism  158 . Alternatively an electrically controlled by a limit switch may be used. The control mechanism  158  or limit switch may be secured to the centering arms, or elsewhere, to sense when a predetermined pressure has been applied to the side walls of the cope or drag. 
     Similarly the front and rear centering arms  32  are supplied with mechanical energy from hydraulic cylinder  36 , driven by valve  160  controlled by a fluid control mechanism  162  (or alternatively by a sensing device such as a limit switch) to ensure that the centering arms grip the cope or drag with a predetermined pressure. 
     The gripping structure  46  is mechanically driven into and out of gripping contact with the cope, as designated by motion  164  in  FIG. 11  by the hydraulic clamp cylinder  53 . Valve  166  supplies hydraulic fluid to cylinder  53  to impart the gripping action, with gripping pressure being controlled by limit switch  170 . To ensure that the gripping pressure is sustained during subsequent lifting and rotating operations, a second valve  168  supplies hydraulic fluid to the valve  166 . By actuating valve  168 , fluid within valve  166  and cylinder  53  is prevented from escaping. This effectively “locks” cylinder  53  in an extended state whereby gripping pressure on the cope is solidly maintained. 
     Lifting motion of the gripping structure, shown as motion  172  in  FIG. 11  is effected by the pair of hydraulic cylinders  60  supplied in parallel with hydraulic fluid by valve  174 . Valve  174  may be controlled by a limit switch  176 , or by timer switch in the alternative. Rotation of the gripping structure is then performed by hydraulic rotation motor  178 , driven by hydraulic cylinder  180  and valve  182 , which are controlled by mechanically adjustable stops  184  to achieve 180 degree rotation of the cope. 
     Accuracy of the automated device can be attributed to several factors. First, the cope and drag mold halves are accurately positioned and held in place as the gripping structure is attached. Thus prior to lifting, the centering arms are responsible for maintaining accurate alignment, and by virtue of the centering arm geometry, this accuracy is repeatably achieved without the need for expensive machine vision systems or human workers. 
     Once the gripping structure grabs and lifts the sand mold half, accurate positioning alignment is maintained by the precision-guided sliding frame  48 . The frame ensures that the gripping structure lifts the mold away from the centering station while maintaining it accurately on vertical center with respect to the centering station. Dual lift cylinders  50  driven by a common hydraulic supply valve ensure that lifting is performed without any canting or twisting of the gripping structure. 
     Because the mold is held firmly between the respective fixed pins  58  of the gripping pads, and because the axes of the respective gripping pad axles are accurately, axially aligned, the mold remains accurately “on-center” with respect to the vertical centerline of the centering station even as it is rotated 180 degrees. While the individual spring loaded pins can extend and retract, as needed, during rotation, the mold remains in accurate alignment because it is captured between the two fixed pins  58 . Again, no expensive machine vision system or human operators are required to maintain the mold in accurate alignment. Thus when the mold is lowered onto the drag half held on-center below, the automated mechanism ensures that the two mold halves will mate up accurately, and repeatably without the need for human operators or expensive machine vision systems to make any last minute positioning adjustments. 
     The advantage of working automatically, without complex machine vision systems cannot be overstated. The typical foundry environment is hot and noisy, with sand particles everywhere. It is not an environment that is particularly friendly to sophisticated vision systems. Moreover, while foundry workers are well trained to perform their specific job, they are typically not well trained in operating and maintaining complex technical systems. The disclosed auto-closer mechanism is ideal in this environment because it can perform its job accurately and automatically and there are few complex technology components that need adjusting or maintenance. 
     Air Bearing Mold Handler Mechanism 
     Referring to  FIG. 12 , the auto-closer mechanism  10  has been provided with an air bearing mold handler assembly shown generally at  200 . For illustration purposes, the cope  20   c  has been illustrated being gripped by the gripper pad  54 , as more fully explained above. The air bearing mold handler includes a die set platform  202  and a floating carrier plate  204  supported by an air bearing structure  206 . As will be more fully explained, the air bearing structure allows the floating carrier plate to move forward and back and from side to side in the plane of air bearing, allowing the gripping structure also to move in the plane of the air bearing. 
     Referring to  FIGS. 13 and 14 , a first embodiment of the air bearing mold handler  200  is shown in greater detail. The air bearing structure  206  is supported on a bearing stand  208 . Beneath each stand is a vertically oriented centering cylinder  210  that projects a locating pin  212  into an orifice  214  defined in the respective sections of the air bearing structure and also in the horizontal surface of the bearing stand  208 . The centering cylinder  210  is actuable to drive the centering pin into the orifice to thereby lock the upper and lower halves of the air bearing structure  206  together. 
     The entire air bearing mold handler  200  is slideably carried on the supporting rods  216  passing through cylindrical bearings  217  to allow the air bearing mold handler  200  to be raised and lowered by action of the lift cylinders  50  (shown in  FIGS. 15-19 , and also in  FIG. 1 ). 
     Referring to  FIG. 15 , it can be seen that the lift cylinder  50  is attached to the die set platform  202 , whereby the air bearing mold handler  200  may be raised and lowered, carrying with it the gripper structure, including the circular gripping pads  54  and their associated linear rotary actuators  52 . 
     In the embodiment shown in  FIGS. 12-19 , the gripper structure is allowed to float on the air bearing mold handler. This floating action allows for side-to-side and front-to-back movement in the plane of the air bearing, as needed to make accurate alignment of the cope and drag. In this embodiment the drag remains fixed, resting on the platform or conveyor belt of the positioning station. 
     In an alternate embodiment shown in  FIG. 22 , the gripper structure is laterally fixed and the drag is allowed to float side-to-side and front-to-back in the plane of the air bearing  206 . In this embodiment, the drag  20   d  is supported on a scissors jack  310  that functions to raise the drag upwardly into mating alignment with the cope. The scissors jack  310  is mounted on the air bearing structure  206 , so that the scissors jack can float as needed during cope and drag alignment. 
     Alignment Structures 
     As shown in  FIGS. 20 and 21   a - 21   b , the cope and drag mold halves are provided with alignment structures  40  to ensure an accurate fit upon closing the mold. In  FIG. 20 , the cope  20   c  is provided with a cone-shaped recess  220  that mates with a corresponding cone-shaped protrusion  222  formed in the drag  20   d . A channel  223  is provided about the periphery of the protrusion  222 , proving a place to catch any sand that is frictionally ground loose during cope and drag mating assembly. 
     In the embodiment illustrated in  FIGS. 21   a  and  21   b , the cope is outfitted with an alignment core structure  224  that may be inserted into or manufactured into the cope. In one embodiment the alignment core structure is a separate manufactured article installed by inserting and/or bonding to the cope or drag. In another embodiment the alignment core structure can be fabricated, as by molding, using the same material used to fabricate the cope and drag (e.g., chemically bonded sand). The alignment core structure is configured to mate with a corresponding recess  220  formed in the drag  20   d . Preferably, the recess  220  is made somewhat deeper than required to accommodate the alignment core structure thereby defining a sand collection recess  226  to catch any sand that is frictionally ground loose during cope and drag assembly. Other configurations of alignment structure are also possible. 
     Function of Air Bearing 
     Because the molds are made of sand, there is a certain amount of abrasion that occurs as the cope and drag halves are closed on one another. If this abrasion occurs in the alignment structures  40 , then inaccurate closing could occur. The air bearing mold handler addresses this problem by significantly reducing the lateral or side-to-side friction as the drag is lowered onto the cope. Specifically, as the cope  20   c  is lowered (or the drag  20   d  raised), the sidewalls of the alignment structures will naturally rub against one another. Due to the tapered nature of the alignment structures, lowering the cope onto the drag (or raising the drag in to mating with the cope) will cause the cope (or drag) to move laterally from side to side in the plane of the air bearing as indicated by the arrows  230  ( FIG. 20 ). Because the air bearing supports the cope (or drag) for virtually frictionless side-to-side motion, the alignment structures are easily brought into alignment without substantial abrasive force. Without the air bearing, the uniting alignment structures would abrade against one another, causing the structures to lose sand or crumble, resulting in inaccurate alignment. 
     Operational Sequence 
     The sequence of operating the air bearing mold handler will now be discussed in connection with  FIGS. 15-19  and flow diagram  FIG. 23 . The processes implemented in the illustrated operational sequence can be controlled using a suitably programmed processor, an application specific integrated circuit, a suitably configured CNC machine, or by discrete combinational logic, implemented using electronic logic gate circuitry, pneumatic logic valve components or combinations of the two. 
     In  FIG. 15  the air bearing mold handler is shown in the “up” position (Position  1 , step  320  of  FIG. 23 ). The centering cylinders are activated with the air bearing turned off (step  322 ). The cope  20   c  is positioned and centered as discussed above (step  324 ). At this stage the grippers have not yet been deployed to grip the cope. 
     Referring next to  FIG. 16 , and Position  2 , step  326  of  FIG. 23 , the air bearing mold handler  200  is lowered, with centering cylinders  210  remaining activated and air bearing turned off. See step  328   FIG. 23 . The grip cylinders are extended under low pressure and then under higher pressure so that the gripping pads engage the sidewalls of the cope. See step  330   FIG. 23 . Then, as shown in  FIG. 17 , and Position  3 , step  332 , the centering mechanism is released and the lift cylinder  50  is used to raise the air bearing mold handler to the “up” position. See step  334 ,  FIG. 23 . The grippers are then rotated 180° to invert the cope. See step  336 ,  FIG. 23 . Note that, once inverted, the alignment structures  40  in the cope are facing downward. 
     Next, as shown in  FIG. 18 , and Position  4 , step  338 , the drag  20   d  is positioned and centered in the auto-closer (step  340 ,  FIG. 23 ) and the lift cylinder  50  is then used to lower the cope  20   c  while the centering cylinders are released and the air bearings are activated. See step  342 ,  FIG. 23 . The cope and drag are then closed, using the air bearings through floating action to permit any lateral adjustments in the cope, so as to permit the centering structures to align without substantial abrasion. See step  344 ,  FIG. 23 . The grip cylinders are then released, as indicated at step  346 ,  FIG. 23 . Finally, as shown in  FIG. 19 , and Position  5 , step  348 , the lift cylinder  50  hoists the air bearing mold handler to the “up” position and the centering cylinders are activated and air bearings are turned off. See step  350 ,  FIG. 23 . Note how the alignment structures  40  are now mated. The closed mold may then be ejected from the auto-closer machine, as depicted at step  352 ,  FIG. 23 . 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.