Abstract:
A molding machine for producing flaskless molds is provided with at least a cope flask and a drag flask and a pattern plate therebetween. The pair of flasks is alternatively positioned in a horizontal position in which the produced molds are removed and the pattern plate is inserted and removed, and in a vertical mold-forming position in which the sand is charged and compacted. The cope flask, the drag flask, the first squeeze plate, the second squeeze plate are rotatable in unison.

Description:
TECHNICAL FIELD 
     The present invention relates to a machine for producing flaskless moulds. 
     BACKGROUND ART 
     Document EP-0 468 355 discloses a conventional moulding forming machine of the above-mentioned type. This moulding machine is of a type in which a cope flask, a pattern plate and a drag flask are capable of rotating over an angle of 90° between a horizontal position and a vertical position. The horizontal position is associated with inserting the pattern plate between the cope and drag flask before the sand charging and compacting step and is associated with the removing of the pattern plate and the discharging of the cope and drag after the charging and compacting step. The sand charging and compacting step is performed with the cope flask, drag flask and pattern plate in the vertical position. The prior art moulding machine uses a first squeeze plate for compacting the sand in the cope flask (the upper flask by definition) and a second squeeze plate for compacting the sand in the drag flask (the lower flask by definition). The second squeeze plate is inserted into the drag flask when the latter is in the vertical position. Because of the rotating movement of the drag flask with respect to the fixed second squeeze plate, it is difficult to align the drag flask with the second squeeze plate in a precise and reproducible manner. The exact alignment in the prior art machine has to be carried out by the compression frame, which has already another important function, namely the transmission of the force for compacting the sand from one squeeze plate to the other. Therefore, the above described second squeeze plate cannot always be smoothly introduced into the drag flask due to deviations in the alignment of the two components. 
     It is the object of the present invention to provide a moulding machine for producing flaskless moulds of the kind referred to above, with which it is possible to overcome the disadvantages mentioned above and which allows easier alignment of the second squeeze plate with the drag flask, thus resulting in a simpler construction of the components of the machine and in higher quality drags and copes. This object is achieved with a machine for producing flaskless moulds in which the cope flask with a first squeeze plate and the drag flask with an associated second squeeze plate are supported by a swing frame and rotatable in unison between the horizontal position and the vertical position. With this arrangement, the alignment function of the compression frame is transferred to the swing frame which takes care of all alignment, whereas the compression frame is only constructed to transmit the relatively large forces related to the compacting of the sand. Thus, the second squeeze plate is always kept in alignment, avoiding problems associated with reproducibility of position. The lower and upper squeeze plates as well as the drag and cope flask are rotated over approximately 90° to take their vertical position in which the cope flask and drag flask are filled with sand. After the sand-filling, the compacting of the sand also takes place in, the vertical position. 
     According to a further embodiment, the swing frame which carries the squeeze plates and the flasks is received in an opening in the compression frame. 
     According to another embodiment of the invention, the drag flask is arranged to be movable up and down with respect to the fixed cope flask when the cope flask and drag flask are in their horizontal position. 
     In an embodiment of the present invention, the second squeeze plate is inserted in the drag flask when the cope flask and drag flask are in their horizontal position. 
     According to a further embodiment, the second squeeze plate serves as a table to receive and lower the superposed cope and drag when the latter are discharged from the cope flask and drag flask, thus doing away with the need for an additional transport table. 
     According to a further embodiment, the sand-charging openings of the respective cope flask and drag flask will, when the latter are moved into their vertical position, engage the sand-blowing nozzles of the blowhead. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following detailed part of the present description, the invention will be explained in more detail with reference to the exemplary embodiments of the machine for producing flaskless moulds according to the invention shown in the drawings, in which 
     FIG. 1 shows a view of the moulding machine from the side in a state just before a mould-forming operation, 
     FIG. 2 shows the machine in the same state from the front, 
     FIG. 3 shows the state in which the pattern plate has been inserted into the machine, 
     FIG. 4 shows the machine in a state in which the mould flasks are brought together with the pattern plate in between them, 
     FIG. 4.1 shows the machine in the same state as in FIG. 4 from the side, 
     FIG. 5 shows the machine in a side view, with the flasks and squeeze plate arrangement rotated into the vertical position and the flasks being filled with sand, 
     FIG. 6 shows the next state in which the sand is being compacted, 
     FIG. 7 shows the flasks containing compacted sand returned in the horizontal position, 
     FIG. 8 shows a view from the side as in FIG. 2, but with the drag flask lowered in order to allow the pattern plate to be taken out of the moulding machine, 
     FIG. 9 shows the next state in which the flasks with the cope and drag are brought together again without the pattern plate between them in order to allow for the now superposed cope and drag to be ejected from the flasks, and 
     FIG. 10 shows the machine in a state in which the superposed cope and drag are placed on the lower squeeze plate which has been lowered so that the finished mould can be ejected on to a conveying means next to the moulding machine. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1-10 elucidate the steps which are carried out by the machine according to the invention in order to produce a flaskless mould. FIGS. 1,  5  and  6  are side views of the machine, whereas for practical reasons FIGS. 2-4 and  7 - 9  are front views of the machine according to the invention. The moulding machine shown in FIG. 1 is provided with a base frame  1  which carries the other components of the machine. A swing frame  2  is rotatably mounted to the base frame  1  through a shaft  2   b . The swing frame can be rotated by an actuator  2   a . The actuator  2   a  is preferably a hydraulic cylinder fastened to the base frame  1  at one of its lateral ends and with its piston rod fastened to the swing frame  2  at a suitable distance from the shaft  2   b . The swing frame  2  supports the cope flask  3  and drag flask  4  as well as the first squeeze plate  5  and second squeeze plate  6 . The cope flask  3  is fixed on the swing frame  2 . The first squeeze plate  5  is suspended by two guide rods  5   a ,  5   b  from the swing frame  2  by a linear bearing which allows a relative movement of the first squeeze plate  5  with respect to the cope flask  3 . The upper ends of the guide rods  5   a ,  5   b  are connected to one another by a bracket  33 . A first linear actuator  7 , preferably a hydraulic actuator, is secured at one of its ends to the swing frame  2  and at its other end to the bracket  33  so that the first squeeze plate may be moved up and down. The first squeeze plate  5  is movably fitted in the cope flask  3 . 
     A drag flask  4  is disposed below the cope flask  3 . The drag flask  4  is suspended from the swing frame  2  by a pair of guide rods  8 ,  9  to allow a linear movement with respect to the latter. The guide rods  8 ,  9  are connected at one of their lateral ends to the swing frame and their opposite lateral ends are inserted into linear bearings in the drag flask  4 . Two second linear actuators  10  are fastened with one end to the drag flask  4  and at the opposite end to the swing frame  2 . Thus, the drag flask  4  can be moved up and down by the second actuators in order to move the drag flask  4  towards and away from the cope flask  3 . 
     The cope flask  3  and the drag flask  4  define on their right-side wall (“right” as in FIG. 1) sand-charging openings  11 ,  12 . The sand-charging openings are placed such that they abut with sand-blowing nozzles  24 ,  25 , when the cope flask  3  and the drag flask  4  are rotated to the vertical position. 
     The second squeeze plate  6  is movably fitted within the drag flask  4 . The second squeeze plate  6  is suspended from the swing frame by a second pair of guide rods  13 ,  14  which are inserted in linear bearings in the swing frame  2 . One third actuator  13   a , preferably in the form of a hydraulic cylinder which may also provide for the linear bearing function, is fastened on one of its ends to the swing frame  2  and at its opposite end to the second squeeze plate  6  for allowing movement up and down of the squeeze plate  6 . 
     A pattern plate  15  is suspended from the swing frame  2  in order to allow a horizontal translative movement of the pattern plate  15  in and out of the space between the flasks (FIG.  2 ). The pattern plate carrier  15   a  has suspending members  34  at two corners thereof, each of the suspending members having a roller  35  at the top portion thereof, and two rollers  35  are attached to the remaining two corners of the carrier plate  15   a.  Both the cope flask  3  and the rotatable swing frame  2  have on the front surface thereof, a rail  16  disposed horizontally to correspond to the rollers  35 . A fourth actuator  17  secured at one of its ends to the cope flask and at its opposite end to the pattern plate carrier allows movement of the pattern plate in and out of the moulding machine. 
     A compression frame  18 , carried by the base frame  1 , extends horizontally. The compression frame  18  is suspended from the base frame so as to allow a horizontal translative movement in order to allow equalization of the force exercised on the first squeeze plate  5  to the second squeeze plate  6 . The compression frame  18  comprises a tie  30  arranged horizontally, longitudinally and laterally disposed on each side of the rotatable frame. The ties  30  are guided so as to allow the above-mentioned horizontal translative movement. The ties  30  are connected to each other at one of their lateral end portions by a connection bar  31 . Thus, the compression frame  18  defines an opening  19  between the two ties which is large enough to receive the rotatable frame  2  together with the drag flask  4  and the cope flask  3  in both the vertical and the horizontal position. A fifth linear actuator  22 , preferably a hydraulic cylinder having a piston rod  21 , is fastened to the connection bar  31 . The second squeeze plate  6  is moved towards the pattern plate  15  by the force of the hydraulic cylinder  22  by the piston rod  21  engaging the second squeeze plate  6 . The compression frame  18  transmits this force through the ties to its other lateral end which is open, i.e., the other lateral ends of the ties  30  are not connected to one another. These lateral ends of the ties  30  are provided with abutment plates  32  which extend towards one another. The abutment plates  32  engage with the bracket  33  for transmitting the compression force to the first squeeze plate  5 . 
     A blowhead  23  with a sand-inlet part at its top and two sand-blowing nozzles  24 ,  25  at its lower side is attached to the base frame  1  in a position so that the sand-blowing nozzles  24 , 25  will engage the respective sand-charging openings  11 ,  12  of the drag flask  4  and cope flask  3  when the latter are in their vertical position. 
     The production process of moulding a flaskless mould comprising two mould halves with the machine according to the invention will now be described with reference to FIGS. 1-10. The sequence of operation starts in the state shown in FIGS. 1 and 2, with the flasks in a horizontal position and with the drag flask lowered to its lowermost position. Next, the pattern plate  15  is displaced laterally into the space between the cope flask  3  and the drag flask  4  (FIG.  3 ). The drag flask  4  and the second squeeze plate  6  are moved upwards towards the cope flask  3  by the second actuator  10  and the third actuators  13   a,  respectively, thereby clamping the pattern plate  15  between the cope flask  3  and the drag flask  4 . In this state, the first squeeze plate  5 , is inserted into the cope flask  3 , the second squeeze plate  6  is inserted into the drag flask  4 , and these components are all in alignment (FIG.  4 ). 
     In the next step, the swing frame is rotated over 90° from the horizontal position to the vertical position by the hydraulic cylinder  2   a , as shown in FIG.  5 . The sand-blowing nozzles  24 ,  25  of the blowhead  23  now abut with the sand-charging openings  11 ,  12  of the respective flask. In the following step, the mould-half forming spaces in the cope flask  3  and the drag flask  4  are filled with sand by supplying compressed air into the blowhead  23 . 
     Thereafter, the charged sand is compacted by the first pressure plate  5  and second pressure plate  6  being forced further into the cope flask  3  and drag flask  4 , respectively. Hereto the fifth actuator  22  which is fastened to the right-side compression frame  18  and the piston rod  21  is actuated so that the piston rod  21  forces the second squeeze plate  6  into the drag flask  4 . The force thus exercised on the drag flask is transmitted through the compression frame to the first squeeze plate via the abutment plates  32  and the bracket  33 . Since the compression frame  18  is horizontally suspended so that it can move longitudinally, the force exercised on the pressure plates is equalized (FIG.  6 ). As a result, a cope  26  and a drag  27  are moulded by compression in the cope flask  3  and the drag flask  4 . 
     After a predetermined time interval, in which the squeezing is completed, as a next step, the swing frame  2  is rotated over 90° back from the vertical position to its starting position, in which the cope flask  3  and drag flask  4  take their horizontal position (FIG.  7 ). 
     In a further step, the drag flask  4  and the lower squeeze plate  6  are lowered in unison and the pattern plate  15  is lowered to take its position in between the cope flask  3  and the drag flask  4  (FIG.  8 ), causing the pattern plate  15  to separate from the cope flask  3  by being lowered while resting on the drag flask until the rollers  35  of the suspending member  34  engage the rails  16 . Next, the pattern plate  15  is retracted from the space between the cope flask  3  and the drag flask  4  by the fourth actuator  17  to take its position as shown in FIG.  2 . The drag flask  4  and the second squeeze plate  6  are raised in unison until the upper surface of the drag flask  4  is in contact with the lower surface of the cope flask  3 , causing the mould surface of the cope to be brought into contact with the mould surface of the drag. Thus, the cope  26  and the drag  27  are superposed (FIG.  9 ). 
     Thereafter, the first squeeze plate  5  is lowered by the first actuator  7  to separate the cope  26  and drag  27  from the cope flask  3  and drag flask  4 . The second squeeze plate  6  is simultaneously lowered and serves as a table for the superposed cope  26  and drag  27  and transports the cope  26  and drag  27  downwards to a position in which the superposed cope  26  and drag  27  can be expelled from the moulding machine (FIG.  10 ). In the following step, a sixth actuator  28  pushes the superposed cope  26  and drag  27  from the lowered second squeeze plate  6  onto a conveyor means  29  adjacent to the moulding machine. 
     The machine has reached its starting position again and is ready for producing the next mould, as part of a cycle operation which is repeated for mass production of flaskless moulds. 
     Although the above described embodiment is illustrated with a fixed cope flask  3  and a movable drag flask  4 , the cope flask  3  may instead be arranged movable and the drag flask  4  may be arranged fixed to the swing frame  2 . 
     LIST OF REFERENCE NUMERALS 
       1  base frame 
       2  swing frame 
       2   a  actuator 
       2   b  shaft 
       3  cope flask 
       4  drag flask 
       5  first squeeze plate 
       6  second squeeze plate 
       7  first actuator 
       8  guide rod 
       9  guide rod 
       10  second actuator 
       11  sand-charging opening 
       12  sand-charging opening 
       13  guide rod 
       13   a  third actuator 
       14  guide rod 
       15  pattern plate 
       15   a  pattern plate carrier 
       16  rail 
       17  fourth actuator 
       18  compression frame 
       19  opening 
       21  piston rod 
       22  fifth linear actuator 
       23  blowhead 
       24  sand-blowing nozzle 
       25  sand-blowing nozzle 
       26  cope 
       27  drag 
       28  sixth actuator 
       29  conveyor means 
       30  tie 
       31  connection bar 
       32  abutment plates 
       33  bracket 
       34  suspending member 
       35  roller