Patent Publication Number: US-7210515-B2

Title: Squeeze station for automated molding machine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This patent application is a divisional of U.S. patent application Ser. No. 11/005,642, filed 12/06/2004 now U.S. Pat. No. 7,117,924. 

   FIELD OF THE INVENTION 
   The present invention generally relates to automated matchplate molding machines for forming sand molds for use in foundries, and more particularly relates to apparatus in such mold making equipment for stabilizing drag flasks and/or apparatus for facilitating release of cope molds from cope flasks according to different aspects of the invention. 
   BACKGROUND OF THE INVENTION 
   Foundries use automated matchplate molding machines for forming sand molds. Formed sand molds are subsequently filled with molten metal material, cooled, and then broken apart to release metal castings. There are several prior art systems for this purpose including several prior art systems assigned to the present Assignee, Hunter Automated Machinery Corporation, including U.S. Pat. No. 3,406,738 to Hunter; U.S. Pat. No. 3,506,058 to Hunter; U.S. Pat. No. 4,890,664 to Hunter; U.S. Pat. No. 4,699,199 to Hunter; U.S. Pat. No. 4,840,218 to Hunter; and U.S. Pat. No. 6,622,722 to Hunter. The entire disclosures of these patent references are hereby incorporated by reference as the present invention may be incorporated or used in these types of molding systems. Additional reference can be had to these patent references for additional details of the state of the art and to see potential applicability of the present invention. While the foregoing inventions have set forth significant advances and advanced the state-of-art to increase the speed and efficiency in which automated sand molding can occur, there is still further room for improvement in automated molding machinery which is the subject of the present invention. 
   BRIEF SUMMARY OF THE INVENTION 
   A first aspect of the present invention is directed toward a releasable lock for preventing relative lateral movement between the platen table and a drag flask during squeezing and compression of sand contained in the cope and drag flasks. Such a lock mechanism minimizes the potential for misalignment of formed cope and drag molds which could be caused by relative lateral movement or wandering of the drag flask due to machine vibrations or other such causes. According to this aspect of the invention, a molding machine includes a cope flask for making cope molds, a drag flask for making drag molds and a pattern plate that is positioned between the cope flask and the drag flask when in a squeeze position. The molding machine also includes a squeeze head that is received into an open end of the cope flask in the squeeze position (with the cope flask extending generally between the squeeze head and the pattern plate), and a platen table that is received in an open end of the drag flask in the squeeze position (with the drag flask extending generally between the platen table and the pattern plate). In accordance with this aspect of the invention, the molding machine also includes a lock between the platen table and the drag flask which prevents relative lateral movement between the platen table and the drag flask in the squeeze position. 
   In this regard, a further aspect of the present invention is that the lock may comprise at least one and preferably two or more actuators in spaced lateral relation and mounted to the platen table, and corresponding structures integral with the drag flask. Each actuator includes a pin (which may be the shaft of a fluid powered cylinder) that is linearly moveable into engagement and out of engagement with a corresponding one of the detent structures, to thereby provide the lock during the squeeze position. Each detent structure may comprise a hole and preferably a tapered blind hole. Further preferred characteristics and settings are further described and claimed herein. 
   According to a different aspect of the present invention, a new way to release a cope mold from the cope flask is disclosed. This aspect generally includes an actuator mounted to the cope flask which drives the cope flask relative to the squeeze head. According to this aspect of the present invention, a molding machine for forming cope molds and drag molds from sands comprises a support frame, a cope flask for making cope molds, a drag flask for making drag molds and a pattern plate that is adapted to be positioned between the cope flask and the drag flask for forming patterned cavities in the cope and drag molds. The squeeze head is received into an open end of the cope flask in a cope mold release mode of the machine. At least one actuator is mounted to the cope flask and to the support frame. The actuator is expandible and retractable to drive the cope flask relative to the squeeze head to thereby facilitate release of the cope mold. 
   Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a partly schematic elevational representation of a molding machine illustrating an embodiment of the present invention and an example of an environment in which the present invention may be implemented. 
       FIGS. 2–12  are partly schematic side elevational views of relative components of such a molding machine shown in  FIG. 1 , including the squeeze and sand mold release station of the molding machine shown in  FIG. 1  (with adjacent stations being shown in some of the figures), and in which each figure shows in sequence different time periods during an operational cycle of such a molding machine to facilitate formation and release of sand molds. 
     While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Turning to  FIG. 1 , an example of an embodiment of an automatic matchplate molding machine  10  is illustrated in schematic form. With the exception of the inventive improvements as discussed herein, the machine illustrated is similar to the HMP type molding machines that are manufactured and commercially available from Hunter Automated Machinery Corporation, the present assignee of the instant patent application. Machines of these types are well known to those of ordinary skill in the art and are widely used throughout the foundry industry. In view of the fact that many of the details of different types of HMP machines or other such machines are known and also shown generally in the aforementioned patents which have been incorporated by reference, discussion of the general operation of the machine will thus be limited and particular focus will be given to the particular inventive improvements to the machine  10  which are discussed and claimed herein. 
   As shown in  FIG. 1 , the molding machine  10  includes a support frame  12 . Different sections of the support frame  12  provide for different work stations including a drag flask filling station  14  and a mold squeeze and release station  16 . The molding machine  10  includes a movable hopper car  18  which includes a sand hopper  20  that is filled with sand. The sand hopper  20  has an openable and closable discharge port  22  which is adapted to align with and discharge sand separately into a cope flask  24  and a drag flask  26 . The hopper car  18  linearly reciprocates horizontally along a top portion of the support frame  12 . The hopper car  18  automatically shifts back and forth between the mold squeeze and release station  16  and the drag flask filling station  14 . This alternately and successively positions the sand hopper  20  at the mold squeeze and release station  16  to fill the cope flask and the drag flask filling station  14  to fill the drag flask. The cope flask  24  is always situated at the mold squeeze and release station  16  during all successive molding operations of the machine  10 , while the drag flask  26  (and pattern plate  28  which is typically secured thereto) is carted back and forth between the two stations  14 ,  16 . To facilitate the horizontal cycling back and forth between the two stations, rollers  30  are provided upon which the drag flask  26  is adapted to ride and roll between the two stations. 
   At the drag flask filling station  14 , the drag flask is received in a rollover cradle  32  that flips the drag flask upside down such that the open end  44  of the drag flask  26  faces the discharge port  22  of the sand hopper  20  allowing the drag flask  26  to be filled with sand. After the drag flask is filled with sand it can then be turned over again by the rollover cradle  32  to an upright position and then shifted to the mold squeeze and release station  16 , where it is assembled with the cope flask that is then filled with sand, squeezed and then disassembled to release the formed cope and drag molds  34 ,  36 . Formed molds  34 ,  36  are then output to downstream mold handling equipment for receipt of molten metal to produce metal castings. 
   The mold squeeze and release station  16  includes several relatively conventional components including a squeeze head  38  that is adapted to be received in an open end  40  of the cope flask and a platen table  42  which is adapted to be received in the open end  44  of a drag flask  44 . As shown, the squeeze head  38  and platen table  42  are arranged in opposition relative to each other with sufficient space provided therebetween to receive the mold flask assembly for the formation of sand molds. Preferably the plunging axis is vertically aligned as shown, with the platen table  42  located vertically underneath the squeeze head  38 . The platen table  42  is actuated by a platen hydraulic cylinder  46  which is operable to raise and lower the platen table  42 . The hydraulic cylinder  46  is also operable to squeeze the cope and drag molds  34 ,  36  contained in the cope and drag flasks  24 ,  26  when the flask assembly is assembled to form and compress the cope and drag molds  34 ,  36 . The hydraulic cylinder  46  is also operable to locate the platen table  42  at different elevations to facilitate release of the drag mold  36  and assemblage of the formed drag mold  36  with the cope mold  34  which is shown in greater detail in the remaining patent illustrations. 
   In accordance with one aspect of the present invention, a lock is provided for selectively locking the platen table  42  to the drag flask  26  to prevent relative lateral movement relative to the actuation/plunging axis during mold squeeze operations. Although the lock may take different forms, a preferred embodiment of the lock comprises at least one pin  48  and at least one corresponding detent  50 . According to a preferred implementation as shown, the pin  48  is the shaft of a pneumatic cylinder  52 . The barrel  54  of the pneumatic cylinder  52  is mounted to the platen table  42  by way of a mounting bracket  56 . Although one pneumatic cylinder may be provided, preferably two pneumatic cylinders  52  with separate pins  48  are provided in side by side relation. This structure may be provided along the same outlet end of the molding machine  10  which is why only one cylinder  52  and pin  48  is depicted in  FIG. 1  since the other one is hidden behind the illustrated one. Alternatively, this structure can also be arranged as illustrated in the remaining illustrations of the present patent application or otherwise in an operable configuration. 
   The detent  50  may be integral with the drag flask  26  as shown, and may be provided by a separate detent block  58  that is mounted rigidly to the drag flask  26 . In this embodiment the detents  50  are provided by holes which may either be through holes or more preferably tapered blind holes  60  which align with corresponding tapered ends  62  of the cylinder shaft/pins  48 . 
   Each pneumatic cylinder  52  is operable via fluid pressure to extend or retract its shaft/pin  48  above and below the top surface of the platen table  42 . This allows formed sand molds to be slid off an output from the molding machine  10  for interference prevention purposes. Each pneumatic cylinder  52  also is set with appropriate pressure relief or a permissible compression such that a maximum force of the cylinders is sufficiently less than the gravitational weight of the drag flask  26  to prevent the drag flask from being lifted off the platen table  42 . In this manner the pneumatic cylinder acts as an air spring to provide a resilient positioning of the pin. Alternative resilient means such as a mechanical spring may be substituted for this feature and function. 
   Turning to another aspect of the present invention, it is seen that the cope flask is vertically supported by hydraulic or pneumatic cylinders  64 . Preferably, two or more pneumatic cylinders  64  are provided and are provided on opposite sides of the cope flask  24  for balancing purposes. One end of each cylinder  64  is mounted to the support frame  12  and extends vertically downward with a second end that vertically supports the cope flask  24 . To mount the second end of each cylinder  64  to the cope flask  24 , a mounting bracket  66  is provided. The mounting bracket  66  is rigidly mounted to the cope flask  24  and has a pivotable connection to the end of the shaft of the cylinder  64 . The cope flask  24  is independently actuated separate from the platen table  42  and thus the fluid powered cylinders  64  are operable to lift the cope flask  24  vertically relative to the squeeze head  38  to facilitate release of the cope mold  34 , while the closed mold is meld form against the squeeze head  38 . 
   With a general understanding of an embodiment of the invention, attention will be given to potential operational characteristics for an embodiment of the present invention, with reference to  FIGS. 2–12 . These figures show different time periods or stages during a mold cycle and are numbered in chronological sequence. 
   Turning then to  FIG. 2 , this illustration shows a point in time during an individual sand mold molding cycle at which a drag flask  26  has been filled with sand (which was previously done at the drag flask and filling station  14  shown in  FIG. 1 ). The drag flask  26 is situated on top of the platen table  42  with the previous mold being output off the molding machine for later processing. As also shown, the cope flask  24  is spaced vertically above the drag flask in substantial alignment. The cope flask  24  in this position is vertically elevated by the two pneumatic cylinders  64  and thus is supported through the top of the support frame  12 . Also in this position, the hopper car  18  is shown at an out position in which the squeeze head  38  is displaced from the mold squeeze release and release station  16 , and in which the discharge port  22  of the sand hopper  20  is aligned with the open end  40  of the cope flask  24 . In this position, the lock may be released (but ready to be engaged) with the pins  48  of the respective pneumatic cylinders  52  retracted below the top surface of the platen table  42 . 
   Moving the process forward and turning to  FIG. 3  then, the pneumatic cylinders  52  drive their respective locking pins  48  into engagement with corresponding tapered blind holes  60  formed into the detent block  58 . This locks the drag flask  26  to the platen table  42  and prevents the drag flask  26  from migrating or wandering horizontally relative to the platen table  42 . This better ensures and maintains proper alignment throughout the entire mold compression and forming cycle. Also as shown in  FIG. 3 , mold lock pins  68  have been actuated by a suitable actuator to project above the top surface of the platen table and project into the internal cavity and sand contained within the drag flask  26 . At the same time as these things are occurring, the platen hydraulic cylinder  46  is raising and has raised the drag flask  26  and the pattern plate  28  carried thereby into engagement with the cope flask  24  with alignment being facilitated by suitable pin and hole alignment mechanisms. It should also be noted that the platen hydraulic cylinder  46  is more powerful than the cope flask cylinders  64  and thus can overcome the power of the cope flask cylinders to drive the entire mold flask assembly vertically upward. Suitable pressure relief valves or other pneumatic controls may be provided to set the maximum biasing force that may be exerted by the cope flask cylinders  64  or alternatively the compressive nature of pneumatic fluid may be used to facilitate this feature. 
   Turning to  FIG. 4 , showing a subsequent stage in the cycle, sand has now been dumped into the cope flask  24  and over the top side of the pattern plate  28 . At this point the sand contained in the cope and drag flasks  24 ,  26  comprise loose uncompressed sand which make up and take the general outline for the cope mold  34  and drag mold  36 . 
   Turning to  FIG. 5 , showing a further subsequent stage, the hopper car  18  is shifted back inward to align the squeeze head  38  over the cope flask  24  and cope mold  34 . Moving further along,  FIG. 6  shows the platen hydraulic cylinder  46  facilitating squeezing of the sand material contained in the cope and drag flasks  24 ,  26  with the squeeze head  38  being received into the top open end  40  of the cope flask in the platen table  42  projecting vertically up into the bottom open end of the drag flask  44 . The platen table  42  works against the squeeze head  38  to compress the loose sand material and form the sand material into the desired formed shapes of the cope mold  34  and drag mold  36 . 
   During this step, typically vibration is used via vibration mechanisms which shake the material to ensure that air pockets and gaps do not occur within the formed sand material of the respective molds  34 ,  36 . It is an advantage that the lock provided by the locking pins  48  and the detent block  58  prevent slight misalignments or wandering movement of the drag flask  26  that could otherwise occur with machine vibrations thereby better ensuring for proper alignment to ensure the proper patterns and alignment of such patterns are formed into the respective cope and drag molds. In comparing  FIGS. 5 and 6 , it should be noted that the locking pins  48  of each pneumatic cylinder  52  has been retracted slightly into the respective barrel  54  of the pneumatic cylinder by virtue of the platen table  42  moving upwardly and projecting inwardly into the drag flask  26 . It is a feature that each pneumatic cylinder  52  is set to provide a relatively low pressurized force to generally act as an air spring such that each pin resiliently engages the corresponding tapered blind hole  60  formed into the detent block  58 . This can be accomplished through appropriate pressure release pneumatic controls and/or through compression of the compressible pressurized air contained within the barrels  54  of the pneumatic cylinders  52 . Alternatively this also can be achieved through alternative means such as a suitable mechanical spring, other biasing mechanism and the like. In this manner, the locking pins  48  may be considered to be freely movable vertically to accommodate various relative vertical elevational changes between the drag flask  26  and the platen table  42 . 
   Also, the force settings on the pneumatic cylinders  52  may also be set at a collective level to be less than and sufficiently less than the gravitational weight of the drag flask  26  so that when the pins are first engaged to the corresponding tapered blind holes  60  as shown when comparing  FIGS. 2 and 3 , that the pneumatic cylinders  52  and locking pins  48  do not lift the drag flask  26  off of the platen table  42 . Proper alignment is also achieved by virtue of the cooperating tapered surfaces including the tapered end  62  of the locking pins  48  and the tapered interior surfaces of the tapered blind holes  60 . 
   Turning back to the molding cycle, once the cope and drag molds  34 ,  36  have been formed and compressed, the platen hydraulic cylinder  46  lowers the platen table until the drag flask  26  rests on the outer drag flask rollers  30  as shown in  FIG. 7 . Due to frictional forces and compression forces, the cope mold  34  stays suspended within the cope flask  24 . With the drag flask now vertically supported and retained on the drag flask rollers  30 , further retraction of the platen table  42  as shown in  FIG. 8  strips the drag mold  36  from the drag flask  26 . This may be done utilizing the platen lock pins  68  which engage the bottom side of the drag mold  36 . As shown in  FIG. 8 , the locking pins  48  can then be retracted and driven below the top surface of the platen table  42 . At this point, the drag mold  36  rests upon the platen table  42  and the platen lock pins  68  may also be retracted. 
   Once the drag mold is stripped from the drag flask  26  and lowered below the drag flask rollers  30 , no interference exists and the drag flask  26  can then be shifted back toward the drag flask filling station where it is situated in a cradle to be rotated and again filled with sand material, as is shown in  FIG. 9 . 
   Turing to  FIG. 10 , the drag mold  36  is raised on the platen table  42  into engagement with the cope mold  34 . At this point and in accordance with a further aspect of this embodiment of the present invention, with reference to  FIG. 11 , the cope flask cylinders  64  are actuated to lift the cope flask  24  relative to the squeeze head  38  and thereby pop and strip the cope flask  24  from the cope mold  34 . The cope mold  34  is opposed by the squeeze head causing it to rest in a stationary position upon the drag mold  36 . It is an advantage that there is no need to pull the cope flask apart or otherwise vertically drive the squeeze head downward. Instead, the squeeze head  38  may be kept stationary in the vertical dimension to achieve release of the cope mold. With the cope mold  34  released from the cope flask  24 , the now formed mold with the cope mold  34  resting upon the drag mold  36  can be lowered on the platen table  42  via the platen hydraulic cylinder to an elevation where it is suitable to be output to downstream mold handling equipment, as is shown in  FIG. 12 . 
   All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
   The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
   Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.