Patent Publication Number: US-2012031146-A1

Title: Method of fabricating randomly-colorized glass vessels

Description:
U.S. PROVISIONAL AND FOREIGN APPLICATION PRIORITY CLAIMS 
     Priority based on Provisional Application Ser. No. 61/463,546 filed Feb. 19, 2011, and entitled “METHOD OF FABRICATING RANDOMLY-COLORIZED GLASS OBJECTS” is claimed. Priority is also claimed in Mexican Patent Application Folio No. MX/E/2010/048026 filed Aug. 4, 2010 and entitled APLICACION DE COLOR DE MANERA IRREGULAR PARA OBJECTOS DE VIDRIO Y CRISTAL. The entirety of the disclosures of each of the previous applications, 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. One effect traditionally produced by glass-blowing artisans is the infusion of random flows of disparately colored glasses in finished products. The randomness of such colorization 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 is physical dimensions such 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. 
     Accordingly, a need exists for a method of incorporating, within a glass vessel, the unique feature of random colorization in a manner that facilitates ready and reliable reproducibility of predetermined physical dimensions. 
     SUMMARY 
     Implementations of the present invention are generally directed methods of fabricating glass vessels incorporating random colorization by causing the flow of a molten secondary glass within a molten primary glass. Although not so limited in scope, among the glass vessels of particular interest are drinking glasses, cups, bowls, decanters, vases, and selectively closeable bottles. 
     In accordance with an illustratively implemented method, an initial gob of molten primary glass of a first color is gathered. In a typical version, the initial gob is removed from a reservoir or vat of molten glass within 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. In some versions, the distal end of the gathering implement includes a ceramic ball about which molten glass is gathered. A quantity of secondary-glass particles (e.g., frit) of a second color is then introduced into the initial gob in order to form a particle-containing gob. Illustratively, the particles are introduced by dipping and rolling the initial gob in a container (e.g., a tray) of secondary-glass particles. Among alternative versions, the particles vary in size from fine powder or dust to relatively macroscopic shards or fragments. Moreover, since it is a principal objective of various implementations to create randomized color effects, the secondary glass from which the secondary-glass particles are formed contrasts in color with the primary glass. 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. 
     The particle-containing gob is heated such that the secondary-glass particles melt and the secondary glass flows within the primary glass. Randomized flow effects are facilitated by the selective rotation and axial reorientation of the gathering implement. In at least one illustrative implementation, the gob of primary and secondary glass is introduced into a reservoir (e.g., a vat inside a glass furnace) of the primary glass in order to cover the gob of primary and secondary glass with an additional “layer” or “coating” of primary glass. The gathering implement is manipulated in order to allow heat from the second gather to penetrate the first gather of primary and secondary glass and cause the glasses to “flow through” one another. The objective in not to create a single, homogenously-blended color, but to retain the visibility of the disparate colors while having the secondary glass become molten and flow through the primary glass in order to create randomized flow patterns. 
     Depending on the type of vessel being fabricated, the gob of primary and secondary glass is sequentially introduced into one or more molds. In accordance with one implementation, the gob of primary and secondary glass is introduced into a shaping cavity defined by the interior walls of a multi-piece pre-form mold. More specifically, in one such implementation, the gathering implement is oriented at an angle sufficiently steep, relative to horizontal, to facilitate the gob&#39;s flowing, under the force of gravity, through an input opening defined in the upper portion of the pre-form mold. With the gob in the pre-form mold, the top opening is sealed and a quantity of gas (e.g., air) is injected into the pre-form mold in order to form the gob of primary and secondary glass into a pre-form vessel. After removal from the pre-form mold, the vessel perform is introduced into finish mold and a quantity of gas (e.g., air) is injected into the finish mold in order to form the pre-form vessel into a finished vessel. 
     In fabricating a more complex glass object, such as a bottle including a neck, the use of a pre-form mold facilitates intermediate shaping, thereby obviating logistical difficulties and diminished quality attendant to the single-mold formation of a shapeless gob into the final shape desired. However, it is to be understood that, absent explicit limitations to the contrary, within the scope and contemplation of the invention as defined in the appended claims are versions involving only a single molding step. Moreover, 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 is regarded as a pre-forming step involving a pre-form mold, while at least one other step is regarded as a finish molding step involving a finish mold. 
     In alternatively implemented versions, 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 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, particle infusion, and heating 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 a 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 gathered gob of molten primary glass being extracted from a glass furnace; 
         FIG. 2  shows the generally ellipsoidal gob of  FIG. 1  being rolled in a tray of secondary-glass particles in order to form a particle-containing gob; 
         FIG. 3  illustrates the heating of the particle-containing gob in order to melt the secondary-glass particles and form a molten gob of primary and secondary glass; 
         FIG. 3A  shows the addition primary glass over the gob of  FIG. 3 ; 
         FIG. 4  shows the gob of primary and secondary glass being deposited into a closed vessel-defining pre-form mold; 
         FIG. 5A  depicts the opened 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 the non-finally-shaped pre-form vessel after removal from the pre-form mold; 
         FIG. 5C  depicts the non-finally-shaped pre-form vessel 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 ; 
         FIG. 6A  depicts the finish mold of  FIGS. 5C and 6  in an open position with the finally-shaped pre-form vessel still disposed therein; and 
         FIG. 7  shows a finished vessel in the form of a bottle being introduced into a continuous annealer. 
     
    
    
     DETAILED DESCRIPTION 
     The following description of methods of fabricating a glass vessel with random colorization, and of glass vessels fabricated in accordance therewith, 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 randomly-colorized glass vessel. With initial reference to  FIG. 1 , an initial gob  20   i  of molten primary glass G P  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 initial gob  20   i  a generally ellipsoidal shape. 
     A shown in  FIG. 2 , the initial gob  20   i  is dipped and rolled in a tray  100  containing secondary-glass particles  30  made from secondary glass G S . Depending on the desired effects, the initial gob  20   i  is rolled to a greater or lesser extent in the secondary-glass particles  30  to form a particle-containing gob  20   PC , a completed version of which is shown in  FIG. 3 . The secondary-glass particles  30  associated with alternative implementations range in size from glass dust to macroscopic shards or fragments. It is noted, however, that smaller particles  30  will heat and melt more quickly than larger particles  30  of the same secondary glass G S . The secondary glass G S  contrasts in color with the primary glass G P . Moreover, in some versions, a plurality of secondary glasses G S  of disparate colors is used. 
     With a desired quantity of secondary-glass particles  30  introduced into the initial gob  20   i , the particle-containing gob  20   PC  is heated, as shown in  FIG. 3 , in order to melt the secondary glass G S  and form a gob  20   PS  of primary and secondary glass. Randomized molten flows of secondary glass G S  are induced within the molten primary glass G P  by the selective manipulation of the gathering implement  10 . Reheating of the gob  20   PS  of primary and secondary glass is sometimes necessary to complete the melt and flow process. 
     One illustrative implementation prescribes covering at least a portion of the gob  20   PS  of primary and secondary glass with additional primary glass G P . For illustrative purposes,  FIG. 3A  indicates the addition of primary glass G P  by re-inserting the distal end  12  of the gathering implement  10  into the furnace  15  from which the initial gob  20   i  of primary glass G P  was withdrawn. Adding molten primary glass G P  over the outside of the gob  20   PS  of primary and secondary glass variously facilitates melting of the secondary-glass particles  30  and the flow of melted secondary glass G S  more toward the center of the gob  20   PS  of primary and secondary glass. 
     Following the heat and flow process, an illustrative, non-limiting implementation prescribes a two-stage molding process, including, as shown in  FIG. 4 , the introduction of the molten gob  20   PS  of primary and secondary glass into a pre-form mold  50 . With additional reference to  FIG. 5A , the illustrative pre-form mold  50  first shown in  FIG. 4  includes first and second mold portions  52  and  56  with, respectively, first and second interior walls  53  and  57 . When the first and second mold portions  52  and  56 —which are hingedly joined in the example depicted—are brought into mutual contact, the first and second interior walls  53  and  57  define an internal pre-shaping cavity  58 . In the illustrative version depicted, the pre-shaping cavity  58  is configured to define a pre-form vessel  70 . 
     With continued reference to  FIGS. 4 and 5A , with the molten gob  20   PS  deposited in the pre-form mold  50 , a pneumatic injector  200  injects a quantity of gas  210  into the pre-form mold  50  through an opening  59 . The internal gas pressure is elevated sufficiently to form the gob  20   PS  into a pre-form vessel  70 . While the formation of the gob  20   PS  into a pre-form vessel  70  is shown in  FIG. 5A  with the pre-form mold  50  depicted in an open position, this is only to facilitate explanation; it is to be understood that the introduction of gas  210  into the pre-form mold  50  actually occurs while the first and second mold portions  52  and  56  are in mutual contact (i.e., while the pre-form mold  50  is closed, as in  FIG. 4 ). 
     When the pre-form vessel  70  is sufficiently cool and “self-supporting” to retain its basic shape, the pre-form mold  50  is opened and the pre-form vessel  70  is removed, as shown in, respectively,  FIGS. 5A and 5B . The illustrative pre-form vessel  70  of  FIG. 5B  has a pre-form vessel wall  72  defining a pre-form vessel exterior surface  74  and a pre-form vessel interior surface  76  defining a pre-form vessel cavity  77 . Moreover, the pre-form vessel wall  72  includes “swirls” of secondary glass G S  embedded within the primary glass G P . As shown in  FIG. 5C , the heated pre-form vessel  70  is transferred from the pre-form mold  50  to a finish mold  80 . The illustrative finish mold  80  of  FIG. 5C  includes first and second mold pieces (or portions)  82  and  86  having, respectively, first and second inside walls  83  and  87 . When the first and second mold pieces  82  and  86  are urged into mutual contact to seal the finish mold  80 , the first and second inside walls  83  and  87  define an internal finish-shaping cavity  88 . 
     As shown in  FIG. 6 , in a manner analogous to that associated with shaping in the pre-form mold  50 , a quantity of gas  210  is injected into the finish mold  80 , and into the pre-form vessel cavity  77 , through a pneumatic injector  200  in order to impart to the pre-form vessel  70  its final basic shape and form it into what is subsequently regarded as a finished vessel  90 . After shaping in the finish mold  80 , the finish mold  80  is opened, as shown in  FIG. 6A , and the finished vessel  90  is removed. 
     Referring to  FIG. 7 , an illustrative implementation calls for the processing of the finished vessel  90  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. The illustrative finished vessel  90  shown in  FIG. 7  is a bottle  90   B  having a main body  92  defining an internal storage cavity  94  and a neck  96  depending from the body  92 . As with the pre-form vessel  70  shown in  FIG. 5B , the bottle  90   B  includes a randomized pattern (“swirls,” in this case) of secondary glass G S  embedded within the primary glass G P . 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   B . It will be appreciated that the formation of a relatively narrow neck  96  might best be performed in a multi-stage molding process. This is particularly true when the neck  96  and the neck opening  98  must be fabricated within “tight” or relatively unforgiving tolerances, such as when the bottles  90   B  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.