Patent Publication Number: US-2012036894-A1

Title: Method of fabricating a multi-tone glass vessel from at least two disparately-colored gobs

Description:
FOREIGN APPLICATION PRIORITY CLAIM 
     Priority is claimed in Mexican Patent Application Folio No. MX/E/2010/048024 filed Aug. 4, 2010 and entitled PROCESS DE FORMACION DE UNA CAVIDAD EN LA PARTE INFERIOR DE CONTENEDORES Y BLOQUES DE VIDRIO. The entirety of the disclosure of the previous application, including the drawings, is incorporated herein by reference as if set forth fully in the present application. 
     BACKGROUND 
     The formation of glass into useful and artistic objects dates to at least the 4 th  Century BCE. Among the established techniques for forming glass are flow-molding, press-molding and hand-blowing. Hand-blown glass objects are admired for the artistry and skill required to produce them, and the uniqueness of each piece so produced. In hand-blowing glass, a skilled artisan gathers a gob of molten glass about the distal end of a gathering implement. The gathering implement is typically hollow so that, as the artisan manipulates the implement to shape the gob, he can blow air into the gob to create a cavity within the work piece. In this general manner, a glassblower is able to create vessels such as cups, bowls and bottles. 
     As glass is hand-blown, the artisan might add unique features to the work piece. For example, color might be added by incorporating certain metals or minerals into the glass as it is reheated and worked. The inclusion of such features signifies artistry, skill and uniqueness. However, the very nature of the hand-blowing process renders hand-blown pieces expensive and impractical for use as containers for all but the highest-end products such as fine perfumes and select alcoholic beverages. 
     Contrasting with the artistry associated with hand-blown glass objects is the rapid mass production of strictly utilitarian objects such as window panes and beverage bottles. Among the goals of manufacturing vessels such as drinking glasses and beverage bottles are rapid reproducibility and uniformity of appearance among units. Of particular importance is uniformity among units in physical dimensions such as opening shape and size in order to facilitate the use of standardized lids, plugs or caps as closures. Accordingly, in the modern era, glass vessels are largely produced by strictly-controlled automated hot pressing and blowing processes. Such processes have the advantage of being relatively inexpensive and invariant, but result in products lacking uniqueness and artistry. 
     A process for producing a multi-tone glass vessel from at least two disparately-colored molten-glass gobs yields vessels combining the artistry and uniqueness traditionally resulting from hand-blowing with the dimensional reproducibility required for mass production. 
     SUMMARY 
     Implementations of the present invention are generally directed to a method of mass-producing consistently-dimensioned, multi-tone (e.g., two-tone) glass vessels from at least two disparately-colored molten-glass gobs while maintaining structural integrity. For purposes of conceptualizing the desired color contrast, it is to be understood that “transparent” or “clear” is regarded as a color throughout the present description and the claims appended hereto. Accordingly, one glass might be transparent, while another at least partially opaque. Although not so limited in scope, among the glass vessels of particular interest are drinking glasses, cups, bowls, decanters, vases, and selectively closeable bottles intended for the containment of products such as perfume and alcoholic beverages, by way of non-limiting example. 
     In accordance with an illustratively implemented method of making a two-tone vessel of predetermined shape, an “initial” or “first” gob of molten glass of a first color is gathered. In a typical version, the molten-glass first gob is removed from a glass furnace by gathering it about a distal end of an elongated gathering implement such as a rod, tube or gathering iron, by way of example. The first gob is introduced into a pre-form mold into which—in one implementation—an initial quantity of gas, such as air, by way of non-limiting example, is injected in order to form the initial gob into a rudimentary pre-form vessel. The pre-from mold is vertically oriented such that molten glass is introduced through an open upper end thereof and the gas is introduced through an opening at a lower end opposite the upper end. In this manner, the injection of an initial quantity of gas through the lower end of the pre-form mold forms a cavity within the first gob that fills with gas and causes the first gob to expand and rise toward the open upper end of the pre-form mold. It will be appreciated that the end of the “partially-inflated” first gob that is nearest the upper end of the pre-form mold corresponds to what will become the lower end of a finished vessel, while the end of the first gob through which the gas is blown corresponds to what will become an opening in the finished vessel. 
     Once the partially-inflated first gob has assumed a predetermined shape and size, a molten-glass second gob of a second color, contrasting in color with the first color, is introduced into the pre-form mold over the partially-inflated first gob. Steps are taken to ensure that the glass is acceptably distributed within the pre-from mold. With the second gob disposed on top of the partially-inflated first gob, additional gas is introduced into the pre-form mold in order to form the first and second gobs into a single pre-form vessel having at least one pre-form vessel wall defining a pre-form vessel exterior surface and a pre-form vessel interior surface defining a pre-form vessel cavity. The quantity of gas blown into the pre-form mold depends, in part, on the desired wall and base thicknesses of the vessel being formed. 
     In one version, when the pre-form vessel is sufficiently cool and “self-supporting” to retain its basic shape, it is removed, while still hot, from the pre-form mold, and introduced into a finish mold. If required, the pre-form vessel is heated sufficiently to allow final shaping prior to introduction into the finish mold, while care is taken not to deform the pre-from vessel to such an extent that it cannot be processed in the finish mold. With the pre-form vessel disposed within the finish mold, a quantity of gas is injected into the pre-form vessel cavity in order to form the pre-form vessel into a finished vessel having at least one finished vessel wall defining finished vessel exterior and interior surfaces, the later surface further defining a finished-vessel storage cavity. 
     In some implementations, the pre-form and finish molds are actually the same physical mold which, when used in a “pre-forming” step is referred to as a “pre-form mold” and, when used in a “finish-molding” step is referred to as a “finish mold.” In fabricating a more complex glass vessel, such as a bottle including a neck, the use of physically distinct pre-form and finish molds facilitates intermediate shaping, thereby obviating logistical difficulties and diminished quality attendant to the use of a single mold at two different stages of the process in order to form the first and second gobs into the final shape desired. Although the summation of the process to this point has implied molding in two stages, it will be generally appreciated that implementations prescribing more than two molding steps are also within the scope of the invention as defined in the claims. More specifically, even in implementations involving three or more molding steps, at least one such step (e.g., the first molding step) is regarded as a pre-forming step involving a pre-form mold, while at least one other step (i.e., the final molding step) is regarded as a finish molding step involving a finish mold. 
     In alternative implementations, apparatus controlled by a programmable computer are variously utilized in the performance one or more steps. For instance, the use of a computer-controlled pneumatic injector is particularly useful in ensuring that the quantity and pressure of gas injected into the mold is appropriate, precise and selectively tunable. Additionally, at least one multi-piece mold can be opened and closed by computer-controlled pneumatics, hydraulics or motor-actuated linkages. While human involvement is integral to the implementation of some versions, particularly at the gob-gathering and mold-filling stages—where an artisan&#39;s vision and skill might be desired—in alternative versions, even one or more of the steps prior to introduction of the gob into either the pre-form mold, or the introduction of the pre-form vessel into the finish mold, is performed by computer-controlled apparatus. 
     Representative, non-limiting implementations are more completely described and depicted in the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a molten-glass first gob being extracted from a glass furnace; 
         FIG. 2  shows the molten-glass first gob of  FIG. 1  being deposited into an open-top vessel-defining pre-form mold; 
         FIG. 3  depicts the partial inflation, and upward expansion, of the first gob of  FIG. 2  as a gas is introduced into a lower end of the pre-form mold; 
         FIG. 4  illustrates the deposition of a molten-glass second gob, contrasting in color with the first gob of  FIGS. 1-3 , on top of the partially-inflated first gob within the pre-form mold of  FIGS. 1 and 2 ; 
         FIG. 5A  depicts the open pre-form mold and the injection of gas to force the molten gob to assume a non-final shape defined by the pre-form mold, although the pre-form mold would not be open when gas is injected; 
         FIG. 5B  shows a non-finally-shaped pre-form vessel after removal from the pre-form mold; 
         FIG. 5C  depicts the non-finally-shaped pre-form vessel of  FIGS. 5A and 5B  situated in an open finish mold; 
         FIG. 6  shows the finish mold of  FIG. 5C  in a closed position so that gas can be introduced to finalize the basic shape of the pre-form vessel of  FIGS. 5A-5C ; and 
         FIG. 7  illustrates the feeding into an annealer a finished vessel resulting from the molding step associated with  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     The following description of methods of fabricating a multi-tone glass vessel is demonstrative in nature and is not intended to limit the invention or its application of uses. The various implementations, aspects, versions and embodiments described in the summary and detailed description are in the nature of non-limiting examples falling within the scope of the appended claims and do not serve to maximally define the scope of the claims. 
     In conjunction with  FIGS. 1 through 7 , there are described alternative illustrative methods of fabricating a multi-tone glass vessel from at least two disparately-colored molten-glass gobs. With initial reference to  FIG. 1 , a molten-glass first gob  20   a  of first glass G 1  of a first color C 1  is gathered around the distal end  12  of an elongated gathering implement  10  and extracted from a furnace  15 . The gathering implement  10  is manipulated in order to give the first gob  20   a  a generally ellipsoidal shape. 
     The illustrative implementations described with reference to  FIGS. 1 through 7  prescribe multi-stage molding processes, each of which includes, as shown in  FIG. 2 , the introduction of the molten-glass first gob  20   a  into a pre-form mold  30 . With temporary additional reference to  FIG. 5A , the illustrative pre-form mold  30  first shown in  FIG. 2  includes first and second mold portions  32  and  36  with, respectively, first and second interior walls  33  and  37 . When the first and second mold portions  32  and  36 —which are hingedly joined in the example depicted—are brought into mutual contact, the first and second interior walls  33  and  37  define an internal pre-shaping cavity  38 . In the illustrative version depicted, the pre-shaping cavity  38  is configured to define a pre-form vessel  50 . 
     With continued reference to  FIG. 2 , and additional reference to  FIG. 3 , with the molten-glass first gob  20   a  deposited in the pre-form mold  30 , a pneumatic injector  200  injects an initial quantity of gas  210  into the pre-form mold  30  through an opening  39 . The pre-from mold  30  is vertically oriented such that molten glass is introduced through an open upper end  31   U  thereof and the opening  39  through which the gas  210  is introduced is at a lower end  31   L  opposite the upper end  31   U . The injection of an initial quantity of gas  210  through the opening  39  in the lower end  31   L  forms a gob cavity  25  within the first gob  20   a.  Filling the gob cavity  25  with gas  210  causes the first gob  20   a  to inflate and rise toward the open upper end  31   U  of the pre-form mold  30 . 
     Referring to  FIG. 4 , when the partially-inflated first gob  20   a  has assumed a predetermined shape and size, as in  FIG. 3 , for example, a molten-glass second gob  20   b  of a second glass G 2  and second color C 2 , disparate from the first color C 1 , is deposited into the pre-form mold  30  over the partially-inflated first gob  20   a.  With the second gob  20   b  disposed on top of the first, partially-inflated gob  20   a,  an additional, second quantity of gas  210  is introduced into the pre-form mold  30 . The internal gas pressure is elevated sufficiently to form the gobs  20   a  and  20   b  into a single pre-form vessel  50 . While the formation of the gobs  20   a  and  20   b  into a pre-form vessel  50  is shown in  FIG. 5A  with the pre-form mold  30  depicted in an open position, this is only to facilitate explanation; it is to be understood that the introduction of additional gas  210  into the pre-form mold  30  actually occurs while the first and second mold portions  32  and  36  are in mutual contact (i.e., while the pre-form mold  30  is closed), as in  FIG. 3 . 
     When the pre-form vessel  50  is sufficiently cool and “self-supporting” to retain its basic shape, the pre-form mold  30  is opened and the non-finally-shaped pre-form vessel  50  is removed, as shown in, respectively,  FIGS. 5A and 5B . The illustrative pre-form vessel  50  of  FIG. 5B  has a pre-form vessel wall  52  defining a pre-form vessel exterior surface  54  and a pre-form vessel interior surface  56  defining a pre-form vessel cavity  57 . Moreover, the disparately-colored first and second glasses G 1  and G 2  have been mutually fused into a unity structure (the pre-form vessel  50 ). In the illustrative implementation under consideration, the heated pre-form vessel  50  of  FIG. 5B  is transferred from the pre-form mold  30  to a finish mold  70 . The illustrative finish mold  70  of  FIG. 5C  includes first and second mold pieces  72  and  76  having, respectively, first and second inside walls  73  and  77 . When the first and second mold pieces  72  and  76  are urged into mutual contact to seal the finish mold  70 , the first and second inside walls  73  and  77  define an internal finish-shaping cavity  78 . 
     As shown in  FIG. 6 , in a manner analogous to that associated with shaping in the pre-form mold  30 , a quantity of gas  210  is injected into the closed finish mold  70 , and into the pre-form vessel cavity  57 , through a pneumatic injector  200  in order to impart to the pre-form vessel  50  its final shape and form it into what is subsequently regarded as a finished vessel  80 . After shaping in the finish mold  70 , the finish mold  70  is opened in the general manner shown in  FIG. 5C , and the finished vessel  80  is removed. 
     As shown in  FIG. 7 , an illustrative finished vessel  80  is being fed through an annealer  300  in order to cool the glass in a controlled manner and prevent internal stresses that might cause the glass to crack if it is allowed to cool too quickly. The finished vessel  80  has at least one vessel wall  82  defining finished vessel exterior and interior surfaces  84  and  86 . As with the pre-form vessel  50  shown in  FIG. 5B , the finished vessel  80  exhibits a two-tone pattern including the mutually fused first and second glasses G 1  and G 2  of, respectively, first and second colors C 1  and C 2 . It should be noted that, while the delineation between the first and second glasses G 1  and G 2  is depicted as relatively even and “clean” for illustrative purposes, in various implementations, the delineation is actually somewhat unpredictably “smeared,” thereby imparting to each finished vessel  80  unique attributes by which it can be distinguished from other vessels  80  produced in accordance with the same general process in the same molds. 
     As previously explained, alternative implementations involve the use of either (i) a single mold in temporarily separate “pre-forming” and “finish-molding” steps or (ii) two or more physically distinct molds in “pre-forming” and “finish-molding” steps. As a general observation, more intricate final products call for molding in at least two stages with at least two physically distinct molds. For instance, while the formation of a vessel such as a drinking cup might be pre-formed and finish molded in a single physical mold, and perhaps even in a single molding step, a vessel such as a bottle might call for physically distinct pre-form and a finish molds. 
     The particular illustrative finished vessel  80  of  FIG. 7  is a bottle  90  which has a main body  92  defining an internal storage cavity  94  and a neck  96  depending from the body  92 . The neck  96  is narrow relative to the main body  92  and has a neck opening  98  (or channel) extending therethrough that renders the storage cavity  94  in fluid communication with the exterior of the bottle  90 . It will be appreciated that the formation of a relatively narrow neck  96  might best be performed in a multi-stage molding process with at least two physically distinct molds. This is particularly true when the neck  96  and the neck opening  98  must be fabricated within “tight” or relatively unforgiving tolerances, as when the bottles  90  being produced are to be sealed by standardized closures such as caps or plugs (not shown). 
     The foregoing is considered to be illustrative of the principles of the invention. Furthermore, since modifications and changes to various aspects and implementations will occur to those skilled in the art without departing from the scope and spirit of the invention, it is to be understood that the foregoing does not limit the invention as expressed in the appended claims to the exact constructions, implementations and versions shown and described.