Abstract:
An apparatus is disclosed for automatically casting separately molded bowl and rim members and then connecting them together while both are in an upside down position. During the connection of the rim to the bowl, the bowl is preferably supported on two opposing sides by the mold. These procedures reduce deformation of the cast bowl while it is still in a “greenware” condition.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a divisional of U.S. patent application Ser. No. 09/443,513 filed on Nov. 19, 1999. 
     
    
     
       STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    The present invention relates to techniques for casting plumbing fixtures. It is especially well suited for casting toilet bowls having substantially closed rims.  
           [0004]    Toilets have often been cast from ceramic slurries. Typically, the slurry was placed in a porous mold which caused the ceramic material to deposit along the mold walls due to capillary attraction through mold pores. As a hollow remained inside of the material that had been deposited on the mold walls, excess slurry could be drained from the mold interior to clear trapways and other water pathways.  
           [0005]    The newly-formed fixture was referred to as “greenware”. “Greenware” more generally refers to an unfired ceramic, usually one with substantial moisture content, regardless of the color of the item. The greenware toilets were then typically allowed to air dry and then fired in a kiln.  
           [0006]    Various types of automated equipment for casting ceramic plumbing fixtures are known (e.g. U.S. Pat. No. 4,948,087—lavatories; U.S. Pat. No. 5,299,624 toilets). Such equipment can close, pressurize, drain, and open multiple molds to form multiple plumbing fixtures or fixture parts at the same time. With respect to toilets, such equipment works best for toilets that are designed with open rim bottoms. When the toilet rim is designed with a closed bottom, this type of molding requires the rim and bowl to be molded separately (and then joined together, preferably while the two pieces of greenware are still soft). See generally U.S. Pat. No. 2,565,356. Unfortunately, the weight of rims is sometimes so great that this process can cause bowl walls to deform during the process unless extreme care is used (thereby slowing the process considerably).  
           [0007]    To date the prior art had not provided an optimal solution for this problem. The art has been accepting a certain amount of waste, deformity, and/or slower production rates. Thus, it can be seen that a need exists to develop improved techniques for casting such items.  
         BRIEF SUMMARY OF THE INVENTION  
         [0008]    The invention provides a molding apparatus for casting a plumbing fixture having a bowl and rim. There is a frame member, a top mold part, two side mold parts and a bottom mold part. The mold parts are capable of forming an upside down portion of a plumbing fixture when the mold parts are in a molding position.  
           [0009]    There are also mold reciprocating members connected to the mold parts and to the frame member to move the mold parts between the molding position and retracted positions in an automated manner. The mold reciprocating members and the mold parts are constructed and arranged so as to be able to move the bottom mold part down relative to the side mold parts when the side mold parts are still in the molding position.  
           [0010]    Preferably the mold reciprocating members include hydraulic rams. The mold reciprocating members and the mold parts can be constructed and arranged to move both the top and bottom mold parts away from the side mold parts while the side mold parts are still in the molding position. When the molding apparatus forms a bowl, the molding apparatus can be used with a rim support member capable of moving a rim into contact with the bowl after the bottom mold part is moved away from the side mold parts and while the bowl is still at least partially between the side mold parts. The apparatus can also include a conveyor extending below a bottom of the molding apparatus.  
           [0011]    In still another form the invention provides cast plumbing fixtures.  
           [0012]    It will be appreciated that the invention reduces deformities (and associated waste) that are caused by conventional methods of casting and assembling such toilets. Deformities are further reduced when using the present invention because the most fragile portions of the bowl wall remain supported by mold parts when the bowl is first pressed onto the rim. Equipment for facilitating the automation of these methods is also provided.  
           [0013]    These and still other advantages of the present invention will be apparent from the description which follows. In the detailed description below preferred embodiments of the invention are described with reference to the accompanying drawings. These embodiments do not represent the full scope of the invention. Rather the invention may be employed in other embodiments. Reference should therefore be made to the claims herein for interpreting the full breadth of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a schematic view of a plant layout showing, among other things, an apparatus for conducting a preferred method of the present invention;  
         [0015]    [0015]FIG. 2 is a schematic, front elevational view of a molding machine of the present invention, showing the machine prior to molding and with the bottom mold part in a retracted position;  
         [0016]    [0016]FIG. 3 is a view taken along line  3 - 3  of FIG. 2;  
         [0017]    [0017]FIG. 4 is a view similar to FIG. 3, albeit showing the machine in a closed molding stage;  
         [0018]    [0018]FIG. 5 is a cross sectional view taken along line  5 - 5  of FIG. 4;  
         [0019]    [0019]FIG. 6 is a view similar to FIG. 3, albeit showing the machine with the top and bottom mold parts being retracted after bowl portion molding;  
         [0020]    [0020]FIG. 7 is a cross sectional view taken along line  7 - 7  of FIG. 6;  
         [0021]    [0021]FIG. 8 is a view similar to FIG. 7, albeit showing the bottom mold part in process of being replaced with a separately molded rim;  
         [0022]    [0022]FIG. 9 is a view taken along line  9 - 9  of FIG. 8;  
         [0023]    [0023]FIG. 10 is a view similar to FIG. 9, showing the separately formed rim being lifted upside down for attachment to the upside down bowl;  
         [0024]    [0024]FIG. 11 is a view taken along line  11 - 11  of FIG. 10, showing the bowl and rim being positioned adjacent each other;  
         [0025]    [0025]FIG. 12 is a view similar to FIG. 9, albeit showing the side molds retracted and the bowl resting upside down on the upside down rim;  
         [0026]    [0026]FIG. 13 is a view similar to FIG. 9, albeit showing the toilet having been lowered below the mold parts;  
         [0027]    [0027]FIG. 14 is a view taken along line  14 - 14  of FIG. 13;  
         [0028]    [0028]FIG. 15 is a front view of the rim casting machine;  
         [0029]    [0029]FIG. 15A is a view taken along line  15 A- 15 A of FIG. 15;  
         [0030]    [0030]FIG. 16 is a view taken along line  16 - 16  of FIG. 15A, illustrating the molding of a rim in one of the multiple casting molds;  
         [0031]    [0031]FIG. 17 is a view taken along line  17 - 17  of FIG. 15;  
         [0032]    [0032]FIGS. 18 and 19 are views similar to FIG. 17 showing the casting machine in further stages of operation;  
         [0033]    [0033]FIGS. 19A, 19B and  20 A are sectional views illustrating stages of unloading the rim from the casting machine;  
         [0034]    [0034]FIG. 20 is a view similar to FIG. 15, albeit showing the unloading of the cast rim;  
         [0035]    [0035]FIG. 21 is a top view illustrating a turning of the largely dry cast toilet for further processing;  
         [0036]    [0036]FIG. 22 is a view taken along line  22 - 22  of FIG. 21; and  
         [0037]    [0037]FIG. 23 is a view similar to FIG. 22, albeit showing the cast toilet further flipped. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0038]    As shown in FIG. 1, the present invention can be carried out using toilet bowl casting machines  10  and rim casting machines  12 . While the machines form bowl and rim portions separately, they are interconnected by conveyor tracks  14 ,  16  and  18 . Tracks  14  transport products from the casting machines to lateral conveyor tracks  16 , which in turn feed conveyor track  18 .  
         [0039]    Referring primarily to FIGS.  2 - 6 , a toilet bowl casting machine  20  includes an upper mold clamp  22  to which is connected top mold part  32 , and a lower mold clamp  23  to which is connected bottom mold part  34 . There are also side mold parts  24  and  25 . The mold parts are moved inwardly and outwardly by the hydraulic rams  27 . The bottom mold part  34  can be stored on a trolley  30  which can move on track  14  to position bottom mold part  34  on mold clamp  23 . With mold parts  32 ,  24  and  25  already in position, mold part  34  can then be raised into a totally closed mold position by ram  27  (see FIG. 5).  
         [0040]    A conventional ceramic slip casting material is fed under pressure into the mold parts through the channel  26 . As will be understood by those familiar with conventional slip casting, this can form bowl portion  50 . Formation of the trapway  29  in the bowl portion is further facilitated by using pressurized air. Excess slip can then be removed.  
         [0041]    Subsequent to the casting of the bowl, the top and bottom mold parts  32  and  34  are withdrawn (see FIG. 6). The cast greenware bowl  50  is still at this point held upside down above the conveyor track  14  by the side mold parts  24  and  25 . While the bowl  50  is in an upside down position, the bottom bowl mold  34  is moved out from under casting machine  10  (see FIG. 8).  
         [0042]    An upside down separately cast rim  46  takes its place (FIG. 9) and has slip material applied to its lower surface (which faces up as the rim is upside down when this occurs). Rim  46  is then raised on trolley  30  as illustrated in FIG. 10 so that the bottom surface of the rim  46  is brought into contact with the top surface of the bowl  50  (when both are upside down). This results in a cast greenware toilet as shown in FIG. 11, albeit preferably at this point the toilet is still supported by the side mold parts.  
         [0043]    The next step is the release of the cast toilet from the side mold parts. This is shown in FIG. 12. This step can be delayed if desired. However, typically no such delay is needed.  
         [0044]    The cast toilet  60  is then lowered on trolley  30  by the ram  27  with guides  28  as shown in FIG. 13. It is moved over track  14  (as shown in FIG. 14) to track  16 , and then ultimately onto track  18 . At this point it is turned 90 degrees on a vertical axis on turntable  62  after which excess mold material can be removed at finishing station.  
         [0045]    The separate casting of rim  46  is illustrated in detail in FIGS.  15 - 20 A. The rim casting machine  12  includes a frame  52  upon which are slidably supported two clamping clam members  54  and  55  by means of upper rollers  57  and tracks  58 . They are guided by rods  59  and serve to hold two or more pairs of rim mold halves  37 / 38  and  39 / 40  in place. A central plate  67  and two side plates  69  and  70  are sandwiched by the clam members  54  and  55  against the mold halves  37 ,  38  and  39 ,  40 . This is seen in FIG. 17 and is the position wherein the casting material is introduced into the mold halves  37 ,  38  and  39 ,  40 .  
         [0046]    After the casting step, the clam members are moved away from the mold halves  37 ,  38  and  39 ,  40  as shown in FIG. 18. The mold halves are held in place by the hydraulic rams  72  connected to plates  69  and  70 . See generally FIGS. 15 and 20.  
         [0047]    The next step is the 90 degree rotation of the molds and the unloading from the casting machine. This is seen in FIG. 19 and is further illustrated in conjunction with FIGS. 15A, 19A,  19 B and  20 A. It is accomplished by the rotation of shaft  74  connected to central plate  67 . Shaft  74  is rotated by drive motor  76  (see FIGS. 15 and 20) to position the molds from the vertical to the horizontal as seen in FIGS. 15A and 19A.  
         [0048]    With mold halves  39  and  40  positioned under plate  67  and supported by plate  69  as illustrated in FIG.  19 B, mold halves  39  and  40  are lowered by hydraulic ram  72  and moved from plate  69  onto trolley  30 . Mold halves  37  and  38  are unloaded by a 180 degree rotation of shaft  74  and lowered by hydraulic ram  72  in the same manner previously indicated for mold halves  39  and  40 . This is seen in FIG. 20A. The mold tops  40  and  37  are removed, and the rims  46  and  47  are applied to a cast toilet as previously described in conjunction with FIG. 11.  
         [0049]    After the molding of the cast toilet  60 , it is further treated at a station  80 . This is shown in FIGS.  21 - 23 . The cast toilet  60  is positioned onto a lift apparatus  82 . The lift apparatus includes a ram  84  for pivoting an open frame support  85  and flipping the cast toilet and rim  60  towards a more upright position as shown in FIG. 23 (where it is supported against support member  86  which in turn is pivoted by ram  88 ). Vertical height adjustment is afforded by the bellows  90 .  
         [0050]    This positioning allows trimming of mold material from the toilet  60  where in FIG. 22 it is trimmed from the outside, and in FIG. 23, it is trimmed from the inside. The trimmed toilet  60  is then placed on a trolley  30  and moved to a loading station where it is loaded on a drying track. Thereafter, the toilet is fired in a kiln in the usual manner.  
         [0051]    An important feature of the apparatus of this invention is the connection of the rim to the cast bowl when both are in an upside down position, partially supported by the mold, and still greenware. This reduces deformation of the bowl and resulting waste, and permits the use of faster production rates.  
         [0052]    While certain preferred embodiments of the present invention have been described above, it should be apparent to those skilled in the art from the above description that a number of modifications and changes can be made without departing from the spirit and scope of the invention. For example, it would not be necessary to employ a finishing station  80 . Neither is it necessary to have a rim casting machine  12  of the type disclosed which produced multiple rims in a single casting operation.  
         [0053]    While the invention is particularly well suited for use with a closed rim  46 , it could be used with an open one. Further, other molding apparatus could be employed to connect the rim to the toilet bowl. Therefore, it is intended that the scope of the invention not be limited solely by the description of the preferred embodiments.  
       Industrial Applicability  
       [0054]    The invention provides equipment for producing plumbing fixtures such as toilets with reduced incidence of deformities and waste.