Abstract:
Ceramic sanitary wares are cast using equipment that comprises at least one mold made up of two halves presenting relative cavities in which the cast item is formed, rendered capable of movement to and fro along a predetermined direction toward and away from one another through the agency of a first actuator, in such a way that respective mating surfaces of the mold halves can be joined together or separated. Pressure forces acting on the mold halves from within are contained and controlled by a system associated directly with the mold halves, which comprises a mechanism acting on the system itself and on the halves of the mold in such a way as to create a gap affording a free passage to the mold halves when drawn together and distanced one from another. In this way, at least one of the halves can be rendered independent of the containment and control system for demolding purposes.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to equipment for manufacturing sanitary wares made of ceramic material.  
         [0002]     In the art field concerned with the manufacture of ceramic sanitary wares (such as wash basins, water-closet bowls, bidets, etc.), the most familiar and widely used production method is that of preparing a fluid mix (known as a slip, composed of an aqueous component, and a clay component held in suspension), then pouring the mix into respective slip-casting molds that present a structure conventionally of porous nature, fashioned typically from resins.  
         [0003]     Such porous molds are made up of at least two halves (“male” and “female”), joinable together or insertable one into the other to create an internal cavity from which the cast item takes its form.  
         [0004]     The two or more parts of the mold are incorporated into special systems, diversified structurally (according to the type of piece being cast) and composed generally of at least:  
         [0005]     a frame supporting the various parts of the mold;  
         [0006]     motion-inducing and positioning means by which the parts of the mold can be moved at least toward and away from one another in such a way as to allow the release of the cast item when demolded;  
         [0007]     feed components by which the slip is directed into the closed mold.  
         [0008]     Among the known properties of the porous resin mold, moreover, is a relatively high mechanical strength that allows the adoption of pressure slip casting methods, that is to say, procedures whereby the slip is caused to enter the mold and then solidify to the required thickness, under high pressures (generally between 3 and 15 bar).  
         [0009]     Under these high internal pressures, however, forces are generated perpendicularly to the casting surfaces presented by the parts of the mold, and deformation of the mold becomes a potential risk: the directions assumed by the components of the internal forces include both the direction along which the parts of the mold are joined and closed, and directions orthogonal (hence transverse) to the closing direction.  
         [0010]     Accordingly, these forces need to be offset by suitable devices that will ensure their containment:  
         [0011]     as concerning the forces generated in the closing direction of the mold, the slip-casting systems outlined above may (in the case of one prior art solution) utilize a fixed platen to which one half of the mold is attached, and a cylinder acting on a movable platen to which the other half of the mold is attached;  
         [0012]     in the case of the forces generated in directions orthogonal to the closing direction, on the other hand, the present applicant has developed and implemented a device for the containment of such forces (disclosed in EP 1 043 132), wherein one half of the mold is equipped with a frame delimiting a space, between the selfsame frame and the mold half, such as will accommodate an element inflatable with a fluid and designed, operating from externally of the mold, to cushion the forces generated by the pressure of the slip directed into the cavity.  
         [0013]     With this system, in effect, control over the pressure of the fluid within the inflatable element can be adapted continuously to the pressure of the slip, so as to optimize the reaction and consequently avoid potential deformation of the mold, while attenuating any elastic contraction occurring in the mold wall.  
         [0014]     Thus, the containment device in question provides an optimum solution to the problem of containing the transverse forces in play during the casting process, but is still subject to marked limitations on the practical level, identifiable both in the considerable weight of the components employed, and in the fact that interstitial spaces between the mating halves of the mold are occupied by an element of indeterminate geometry.  
         [0015]     More exactly, the weight of the combined mold-and-containment device structure is considerable, and such as can be carried only by certain types of systems, typically multiple-mold type frames for casting wash basins, whereas systems where molds are required to interact and move independently (for example, systems for casting water closet bowls with rim, where one half of a mold—containing the rim—must be transferred from the casting station to a further station where the rim is bonded to the bowl) cannot be equipped with a containment device of this type.  
         [0016]     An added drawback is that certain molds (like the mold in which the aforementioned rim is cast) cannot be equipped with the containment device by reason of their male-female type geometry, with one part insertable into the other part.  
         [0017]     Yet another drawback is that many systems using batteries of molds essentially “traditional” in embodiment (i.e. without the inflatable element), tend to be affected by problems deriving in essence from the application of rigid and fixed containment systems (frames) to at least one of the mold halves. This type of architecture produces drawbacks similar to those mentioned above, that is to say limited maneuverability due to the weight of the mold/containment device assembly, with the result that the operation of changing the mold is rendered slow and difficult, as the containment structure must be dismantled completely from the mold currently in use before being fitted to a new or reconditioned mold. This renders the slip casting system subject to extended down times while in service.  
         [0018]     Accordingly, the object of the invention is to develop and implement equipment for manufacturing sanitary wares of which the structural characteristics will allow its use in any type of casting system, whatever the geometry of the item being cast, and to render the component parts of the mold swiftly and safely movable or slidable one relative to another while maintaining the characteristics of mechanical safety afforded by previous solutions.  
       SUMMARY OF THE INVENTION  
       [0019]     The stated object is realized according to the invention in equipment for manufacturing ceramic sanitary wares comprising a mold made up of at least two halves presenting relative cavities in which the ware is formed, rendered capable of reciprocating movement along a predetermined direction toward and away from one another through the agency of first motion-inducing means, in such a way that respective mating surfaces of the mold can be joined to or distanced from one another.  
         [0020]     The equipment disclosed comprises means associated with and serving to contain and control the forces acting on the mold halves, incorporating release means designed to act on the selfsame containment and control means and on the halves of the mold in such a way as to create a gap by which the mold halves are afforded a free passage when moving toward or away from one another, thereby rendering at least one of the halves independent of the containment and control means. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which:  
         [0022]      FIGS. 1 and 2  show an example of equipment for manufacturing ceramic wares according to the present invention, illustrated respectively in a closed operating configuration of contact between halves of a mold forming part of the equipment, and in an open operating configuration, viewed schematically in side elevation and with certain parts omitted better to reveal others;  
         [0023]      FIG. 3  shows part of the equipment in  FIG. 2 , illustrated in a front view with certain parts omitted and others in section;  
         [0024]      FIGS. 4 and 5  show details P and P 1  of  FIGS. 2 and 1 , respectively, consisting in a part of control means by which to contain the forces acting on the mold in two different configurations, at rest and in operation, both illustrated in a front view with certain parts omitted and others in section;  
         [0025]      FIG. 6  shows a variation in embodiment of the equipment disclosed, illustrated schematically in a front view with certain parts omitted better to reveal others;  
         [0026]      FIG. 7  shows a further variation in embodiment of the equipment disclosed, illustrated schematically in a front view with certain parts omitted better to reveal others;  
         [0027]      FIG. 8  is an enlarged detail A of  FIG. 7 ;  
         [0028]      FIG. 9  shows a third variation in embodiment of the equipment disclosed, illustrated schematically in a front view;  
         [0029]      FIG. 10  is an enlarged detail B of  FIG. 9 , illustrated schematically in section and in a front view;  
         [0030]      FIG. 11  shows the equipment of  FIG. 7  in a partial side elevation with certain parts omitted better to reveal others. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0031]     As illustrated in the accompanying drawings, and with reference in particular to  FIGS. 1 and 2 , the equipment to which the invention relates, denoted  100  in its entirety, is utilized in the manufacture of ceramic wares, particularly sanitary wares (such as wash basins, water-closet bowls, bidets, etc.) produced by a slip-casting process.  
         [0032]     The equipment  100  consists in a mold  1  comprising at least two matched halves  2  and  3  (male and female, respectively), with relative cavities  2   a  and  3   a  from which the cast item takes its form; the two halves are capable of relative movement toward and away from one other, generated by relative first motion-inducing means  4  caused to reciprocate along a predetermined direction A, in such a way as to join or separate respective mating surfaces denoted  2   b  and  3   b.    
         [0033]     In the example of the drawings, illustrated schematically and implying no limitation, the equipment  100  is used to manufacture water-closet bowls with a rim, the mold denoted  1  being the mold used to cast the rim.  
         [0034]     Still referring to  FIGS. 1 and 2 , the equipment  100  can include a cylinder  4   c  by which motion is induced in one mold half  2  (so as to direct this same half  2  toward and away from the other mold half  3 ), and second motion-inducing means consisting in a pair of arms  4   b  by which one mold half  3  (the half containing the cast rim) can be lifted vertically (see arrows F 4   b ) and positioned on a further mold (not illustrated) used to cast the bowl, whereupon the two castings are bonded by a conventional procedure.  
         [0035]     In addition, the equipment  100  can include means  5  by which to contain and control the forces acting on the halves  2  and  3  of the mold  1  (in the course of the casting steps), arranged around the mold cavities  2   a  and  3   a  and comprising, in the first example of FIGS.  1  to  6 , at least one inflatable element  6  filled with a quantity of pressurized fluid such as will produce a first limit configuration of minimum pressure Pmin and contracted dimensions, when at rest (see  FIG. 4 ), and a second limit configuration of maximum pressure Pmax and expanded dimensions, when in operation (see  FIG. 5 ).  
         [0036]     As illustrated in FIGS.  3  to  5  and  7  to  10 , the aforementioned containment and control means  5  further comprise, at least, release means  7  acting on these same means  5  and on the halves  2  and  3  of the mold  1  in such a manner as to create a gap through which the two halves  2  and  3  can pass freely when joined or distanced from one another, thereby rendering at least one of the halves  2  or  3  independent of the containment and control means  5 .  
         [0037]     Observing the structure of FIGS.  3  to  5 , in particular, such release means  7  operate between the halves  2  and  3  of the mold  1  and the inflatable element  6  in such a way as to create a gap through which the mold halves  2  and  3  can pass freely when brought together or distanced one from another, thereby rendering at least one of the halves  2  or  3  independent of the containment and control means  5 ; this could be the half containing the cast item to be transferred to another station, as in the example illustrated.  
         [0038]     In particular, the containment and control means  5  further comprise a first frame  8  surrounding a peripheral outer portion of both mold halves  2  and  3 , when in a closed configuration of contact one with another, and supporting the inflatable element  6  internally.  
         [0039]     More exactly, the release means  7  are interposed between the two halves  2  and  3  of the mold  1  and the inflatable element  6  and connected to the aforementioned first frame  8 , so as to create a predetermined or linear gap through which the two mold halves  2  and  3  can pass freely at least when the inflatable element  6  is at rest, presenting the first limit configuration of minimum pressure and contracted dimensions.  
         [0040]     Preferably, albeit implying no limitation, the first frame  8  will be rigidly associated with the outer surface presented by one half  2  or  3  of the mold  1 , and the same first frame  8  can be equipped with two or more inflatable elements  6 ,  6   a  and  6   b  arranged one beside the next along the aforementioned direction A followed by the mold halves  2  and  3  when joined to and distanced from one another, so as to cover the full depth of the surfaces presented by the mold cavity.  
         [0041]     In greater detail, constructionally, the release means  7  can comprise a movable second frame composed of at least one plate  11  matching the periphery of the first frame  8  at least in part, and associated with the selfsame first frame by way of coupling means  12  in such a way as to establish the gap affording a passage to the halves  2  and  3  of the mold  1  when joined to and distanced from one another, and when the inflatable elements  6 ,  6   a  and  6   b  present their first configuration of contracted dimensions.  
         [0042]     The coupling means  12  in question can be of passive or active type.  
         [0043]     In the case of passive coupling means, these could take the form, for example, of flexible retaining means  12  (see  FIGS. 4 and 5 , in particular) comprising a plurality of pins  13 , each positioned on the outer surface of the first frame  8  and passing through a relative clearance socket  14  afforded by the selfsame first frame  8 , in such a way that one end can be associated with the second frame.  
         [0044]     Interposed between each pin  13  and the first frame  8  is a spring  15  serving to keep the second frame in close association with the first frame  8  when the inflatable elements  6 ,  6   a  and  6   b  present their first configuration of contracted dimensions and, respectively, to adjust or increase the distance between the second frame and the first frame  8  when the inflatable elements  6 ,  6   a  and  6   b  present their second, operating configuration of expanded dimensions (see arrows F 15 ).  
         [0045]     In effect, each spring  15  is retained between the pin  13  and the first frame  8  by a pair of rings  15   a  and  15   b , a first associated with the free outer end of the pin  13  and a second seated against the first frame  8 .  
         [0046]     Coupling means  12  of active type could include a plurality of pneumatic cylinders  13   c  (one of which illustrated schematically in  FIG. 6  with phantom lines, by way of example), each positioned on the outer surface of the first frame  8  and passing through a relative through socket  14  afforded by the selfsame first frame  8 , in such a way that the end, or rod, can be associated with the second frame.  
         [0047]     Each of the cylinders  13   c  can be governed by a control unit  13   a  (indicated by a block in  FIG. 6 ) in such a way as to keep the second frame in close association with the first frame  8 , through the force of the cylinders  13   c , when the inflatable elements  6 ,  6   a  and  6   b  are in their at-rest limit configuration of contracted dimensions, and, respectively, to adjust or increase the distance between the second frame and the first frame  8  when the inflatable elements  6 ,  6   a  and  6   b  are in their operating limit configuration of expanded dimensions.  
         [0048]     Constructionally, by way purely of example, the first frame  8  could present a quadrangular shape when seen in section, and the movable second frame might comprise at least four independent plates  11 ,  11   a ,  11   b , and  11   c  associated one with each side of the first frame and furnished each with the flexible retaining means  12  described above.  
         [0049]     Self-evidently, the shape of the first frame  8  and the number and shape of the plates  11  could be other than as described and illustrated in the accompanying drawings, depending on practical requirements and on the geometry of the molds: in  FIG. 6 , for example, the first frame  8  is of circular section and surrounds a mold  1  of cylindrical embodiment, whilst the plate  11  might appear as a single element matching the shape of the first frame  8 , or as two elements of arched profile, designed likewise to match the geometry of a circular or cylindrical first frame  8 .  
         [0050]     Referring again to  FIGS. 1 and 2 , numeral  9  denotes flow and return means  9  mounted to the first frame  8 , by which the inflatable elements  6 ,  6   a  and  6   b  are supplied with and relieved of fluid.  
         [0051]     Such flow and return means  9 , supplying air, for example, are positioned on the top part of the first frame  8  and insertable through the frame in such a way as to connect in fluid-tight association with the relative inflatable elements  6 ,  6   a  and  6   b.    
         [0052]     To improve the releasability of the porous mold  1  still further, the containment system of the invention is complemented by two further variations in embodiment of the equipment  100 , as in  FIGS. 7 and 9 .  
         [0053]     In both solutions, the release means  7  described above are interposed between the containment and control means  5  and the two mold halves  2  and  3 . In these solutions, the containment and control means  5  are still embodied substantially as a first frame  8  surrounding a peripheral outer portion of both mold halves  2  and  3 .  
         [0054]     Clearly, in the interests of simplicity, both of the alternative embodiments in question could be incorporated into a casting system as described previously, albeit this does not limit the scope for application of the solution to other types of casting systems.  
         [0055]     In the example of  FIGS. 7 and 9 , the containment and control means  5  are shown as comprising a plurality of locating plates  50  arranged so as to surround both of the mold halves  2  and  3  when in the contact configuration, of which the release function is the same as that performed by the plates  11  of the first solution described previously.  
         [0056]     Similarly, release means  7  are located between the plurality of plates  50  and the first frame  8 , surrounding a peripheral outer portion of both the mold halves  2  and  3 , in such a way as to act on the selfsame plates  50 .  
         [0057]     Depending on the geometry of the particular mold  1 , the aforementioned plates  50  can be at least two in number (in the case of a circular mold, for example, as illustrated in  FIG. 6 ), positioned to surround the mold halves  2  and  3  peripherally when in the contact configuration.  
         [0058]     Where the single mold halves  2  and  3  present a quadrangular peripheral outline (see  FIGS. 7 and 9 ), the first frame  8  will be of corresponding quadrangular shape and the plates  50  at least four in number, in such a way as to surround both halves  2  and  3  of the mold peripherally when in the contact configuration.  
         [0059]     In greater detail, these release means  7  comprise motion-inducing mechanisms  70  by means of which the plates  50  can be moved between an operating position of proximity, that is to say of contact between the plates  50  and the mold halves  2  and  3  (see also  FIGS. 8 and 10 ), and a non-operating position of detachment, in which the plates  50  are distanced from the mold halves  2  and  3  so that the selfsame halves  2  and  3  can be separated one from another.  
         [0060]     In the example of  FIGS. 7 and 8 , the motion-inducing mechanisms  70  comprise: a plurality of hydraulic cylinders  71  associated with each plate  50 , and means  72  by which to activate and deactivate the cylinders  71 .  
         [0061]     Each cylinder  71  is associated slidably with a relative mounting  81  presented by the innermost surface of the first frame  8 , and anchored by way of a free end to the relative plate  50 .  
         [0062]     The means  72  of activating and deactivating the cylinders  71  are connected to the selfsame cylinders  71 , and able thus to determine the positions in which the plates  50  are in proximity to and distanced from the mold halves  2  and  3  (see arrows F 71 ,  FIG. 8 ).  
         [0063]     In the event of the hydraulic cylinders  71  being single-acting, the motion-inducing mechanisms  70  might also comprise spring return means  73 , interposed between the first frame  8  and each plate  50  so as to enable the passage of the plate  50  from the position of proximity to the distanced position (see  FIG. 8 ).  
         [0064]     With regard to the means  72  of activating and deactivating the cylinders  71 , these same means  72  can be governed by a master controller  74  such as will allow of varying the reaction pressure of each plate  50  on the mold halves  2  and  3  (during the casting process), by actuating the cylinders  71 , thereby creating containment means of active type.  
         [0065]     Alternatively, the rod  71   a  of each cylinder  71  can be furnished with an adjustable reaction and stroke-limiting element  75  (see  FIG. 8 ), interposed between the rod  71   a  and the first frame  8 , in such a way as to establish a predetermined travel between the position of proximity and the distanced position of the plates  50  (i.e. with a predetermined contact pressure applied to the mold halves  2 ,  3 ), thereby creating containment means of passive type.  
         [0066]     In the example of  FIGS. 9 and 10 , the motion-inducing mechanisms  70  comprise: cam means  76 , and operating and actuating means  78 .  
         [0067]     The cam means  76  are interposed between, the first frame  8  and each plate  50 , and connected mechanically by way of relative rods  77  to the operating and actuating means  78 .  
         [0068]     The cam means  76  comprise a plurality of pivots  79  associated with the single plates  50 , mounted at each end by way of respective eccentric fulcrum points  79   a  to vertical side members  50   s  of the relative plate  50 , in such a way that the plate  50  can be displaced perpendicularly to the corresponding face of the mold halves  2  and  3 , toward and away from the selfsame halves  2  and  3 , by causing the eccentric pivots  79  to rotate through the agency of the operating and actuating means  78  (see arrows F 76  and F 79  in  FIG. 10 ).  
         [0069]     Each pivot  79  is associated with one end of a relative lever  90  connected at the other end to a common rod  77  operating all the levers associated with the plate  50 .  
         [0070]     Each rod  77  is connected in turn to the relative operating and actuating means  78 .  
         [0071]     The operating and actuating means  78  and the cam means  76  are able to determine the aforementioned positions of the plates  50  in proximity to and distanced from the mold.  
         [0072]     The operating and actuating means  78  could include a cylinder  78   c  such as will induce reciprocating linear motion (see arrow F 78 ) in each rod  77 , thereby causing the plates  50  to assume the positions of proximity to and detachment from the halves  2  and  3  of the mold  1  and viceversa.  
         [0073]     As in the example described previously, each cylinder  78   c  can be governed by a master controller  74  designed both to determine the stroke of the cylinder  78   c  in each direction, corresponding to the travel between the limits at which the plates  50  are positioned in proximity to and distanced from the mold, and to introduce a further stroke variation dependent on the reaction pressure applicable preferably to the mold halves  2  and  3  by each plate  50  (and on the steps of the casting cycle), thereby creating containment means of active type.  
         [0074]     In the event that the containment means are of passive type, however, the single cylinders  78   c  will be piloted by the master controller  74  (preferably in concert, though not necessarily), to reciprocate through a stroke corresponding simply to the travel between the limits at which the plates  50  are positioned in proximity to and distanced from the mold (and viceversa).  
         [0075]     In the example of  FIG. 11  (which illustrates a preferred solution, albeit implying no limitation), the first frame  8  is associated with the platen  2   t  of the relative mold half  2  in separable fashion, through the agency of means denoted  83 .  
         [0076]     In particular, and by way of example, implying no limitation on the type of system to which the invention might be applicable, the first frame  8  can be equipped with at least one pair of trolleys  82  running on relative rails  101  presented by the fixed frame  102  of a casting machine.  
         [0077]     More exactly, the first frame  8  incorporates the aforementioned separable means  83  of association with one of the mold halves  2 , in this instance the half denoted  2 , so that the activation of the motion-inducing means  4  (the cylinder  4   c  anchored to the platen  2   t  of the mold half  2 ) will draw the mold halves  2  and  3  together or distance the one from the other, and when necessary, distance the first frame  8  from the mold half  2  associated with the selfsame frame  8 .  
         [0078]     Although not illustrated, the structure in question can also be applied to the first frame  8  of the solution described previously.  
         [0079]     As discernible likewise in  FIG. 11 , the mold half denoted  2  (the male part by way of example, though not necessarily) is associated with the first frame  8  by way of a pair of tie bolts  83   t  (rigid anchor) attached at one end to the edge of the first frame  8 , and at the other end to a bracket  83   m  presented by the platen  2   t  of the mold half  2 : this enables synchronized motion of the two elements (frame and platen) back and forth along the clamping direction of the two mold halves and, when necessary, allows the separation of the frame and platen in the event of a mold changeover.  
         [0080]     In an alternative solution (not illustrated), the separable fastening means  83  might consist in a pair of cylinders such as will allow a calibrated variation of the distance between the platen  2   t  and the first frame  8 , according to the operating requirements of the system.  
         [0081]     In essence, therefore, the equipment  100  described thus far is used in the conventional manner for manufacturing ceramic wares (the rim of a water-closet bowl, in the example illustrated), while providing a system for containment of the forces operating on a porous mold.  
         [0082]     The characteristics of the containment means are such that the mold half in which the cast item remains seated can be released from these same means and distanced from the other mold half, then lifted and carried to a station where the rim is fitted to the bowl, unencumbered by the additional weight of the frames needed to ensure successful containment.  
         [0083]     The characteristic of releasability presented by one part of the mold or by both parts, especially in the former instance, is afforded by the inclusion of the plates between the mold and the inflatable elements, with which it becomes possible to create a “corridor”, as it were, through which the mold parts can pass without disturbing the inflatable elements attached to the first frame.  
         [0084]     In the latter instance, on the other hand, releasability is assured by the inclusion of hydraulic or mechanical means allowing the parts of the mold to separate one from another while keeping the containment system associated fixedly with the structure of the machine.  
         [0085]     This means that the containment system, which in general is very heavy, can also be used in conjunction with molds of which the half that retains the demolded item has to be moved and/or supported by conventional handling systems proportioned mechanically to lift and accommodate the mold part alone, thereby avoiding the need to structure the system with bigger and bulkier lifting and handling means, at greater cost.