Abstract:
A bottle closure formed by injection molding and including a body member having a generally cylindrical portion and at least one generally circular end portion; and markings such as designs, logos, or other identifying information molded into the end portion during the injection molding process. The bottle closures are molded using one or more pins having face plates that are releasably positioned in a mold cavity and are formed with the reverse of the markings. The plates are adapted to be specific to the producer of the contents of the bottle and are quickly and easily swapped in and out of the mold cavity to permit a single mold cavity to be used to produce a variety of customized bottle closures. The closure may be of any desired shape, including the generally cylindrical used, for example in wine bottles, or T-shaped in longitudinal cross section, referred to in the industry as “T tops”, used, for example, in bottles of spirits, vinegars, oils, and the like.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates to bottle closures for sealing bottles, and more particularly, to an injection molded bottle closure having designs, logos, markings, identifying information, or the like molded into the ends of the closure at the time of molding.  
         [0003]     2. Background of the Prior Art  
         [0004]     Traditionally wood cork comprises the most common material for bottle closures. However, continued increases in demand for cork increase the cost of cork, and place a strain on the diminishing supply of cork-producing trees. At least ten percent of bottles today with wood corks are reported to suffer from cork taint caused by 2,4,6-trichloroanisole, or TCA, a fungus-produced compound that grows in cork fiber. TCA causes the musty or moldy odor that can spoil the wine. When the chips or dust of wood cork is used in the manufacture of wood cork agglomerate closures, the TCA can again cause cork taint. Further, variations in the color, compressibility, and rigidity of cork renders a substantial amount of cork unusable for use in bottle closures. Hence, there exists a need for a suitable alternative to natural cork bottle closures.  
         [0005]     Synthetically generated bottle closures are well known in the art, some even utilize thermoplastic resins and blowing agents to create a dense outer skin and a low density interior. U.S. Pat. No. 5,692,629 discloses such a product. These types of bottle closures, however, suffer from several drawbacks. Synthetic bottle closures typically have rough outer surfaces. These surfaces prevent the bottle closure from forming a strong uniform seal of the bottle. A deficient seal allows for leakage of the contents of the bottle, and provides an opportunity for contaminates to enter the bottle. Additionally, the rough appearance renders the bottle closure less aesthetically pleasing. The rough appearance generally results from imperfections in the cellular structure of the bottle closure. Voids and fissures created during the injection molding process provide areas where contaminants can collect, and provide an environment for the growth of bacteria. U.S. Pat. No. 6,139,934, teaches a method of forming bottle closures out of plastic that has a higher cellular density near the surface and a lower cellular density near the core and address many of the problems in the art.  
         [0006]     Bottle closures for wine have traditionally been printed (plastic) or branded (wood) with designs, words, logos and other markings that identify the producer of the wine and perhaps the wine itself. This information has been limited to printing on the surface of the closure body and has not included engraving or imprinting on the ends of the closure. Moreover, these markings are applied by traditional printing techniques after the cork closure has been produced, for example, as described in U.S. Pat. No. 5,904,965. In order to mark the top of a bottle which received a cork closure, the practice has been either to add a foil, plastic, or paper cover. U.S. Pat. No. 5,553,728 describes a thermoplastic disc that is inserted into the neck of a bottle atop the closure and which can be printed or embossed with designs or words. Recently, some bottlers have been recessing the closure in the bottle neck and then placing molten wax atop the closure and imprinting the wax with a design or other marking. These prior art methods require additional steps to be performed after the bottle closure has been inserted and so have the disadvantages of being expensive, time consuming, and requiring additional equipment that must be purchased, installed, and maintained.  
         [0007]     Accordingly, there exists a need for an injection molded bottle closure having end surfaces that displays markings, designs, logos, bottler information and the like that are molded into the closure at the time of manufacture and which are visible after insertion of the closure into the bottle without the need for further equipment or processing.  
       SUMMARY OF THE INVENTION  
       [0008]     An object of the present invention comprises providing an injection molded bottle closure having one or more ends carrying a molded-in imprint.  
         [0009]     Another object of the present invention comprises providing an injection molded bottle closure which visibly displays markings, designs, logos, seller information, and the like upon insertion of the closure into a bottle.  
         [0010]     Yet another object of the present invention comprises providing a method for injection molding customized bottle closures using replaceable mold inserts that permit the quick and easy changes to be made to the mold cavity and consequently to the molded bottle closures.  
         [0011]     Still another object of the invention is to provide a mold insert for imprinting or engraving markings on the end surface of a closure during molding of the closure and which has a concave or convex surface curvature to impart a convex or concave surface curvature, respectively, to the end of the closure.  
         [0012]     These and other objects of the present invention will become apparent to those of ordinary skill in the art upon reference to the following specification, drawings, and claims.  
         [0013]     The present invention proposes to overcome the difficulties encountered heretofore. To this end, a bottle closure is molded according to an injection molding process that utilizes a first mold section and a second mold section which, upon contact engagement with each other, form a mold cavity in which the closure is formed. Formed into at least one of the end portions of the mold sections is the reverse or negative of a customized design, marking, logo, or other identifying information that is formed in on at least one of the ends of the closure. In a preferred embodiment, the negative design is formed on the end of one or both of a pair of replaceable pins which are received in either of the mold sections. The information is either in the form a raised portion of the face of the pin, depressed portions of the face of the pin, or a combination of both. An injection mixture is injected into a mold cavity formed between the first and second mold sections. Upon satisfactory cooling of the injection mixture, the formed closure is ejected from the mold. The end of the closure that formed in contact with a pin carrying the negative design or other identifying information will carry a positive impression of the design or identifying information. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a side elevation view of an injection molding machine.  
         [0015]      FIG. 2  is a cross-sectional view of the mold unit of the injection molding machine of  FIG. 1  for molding a cylindrical bottle closure such as a wine bottle closure and showing a pair of removable pins for forming impressions or markings on one or both of the ends of the bottle closure.  
         [0016]      FIG. 3  is a cross-sectional view of the mold unit of the injection molding machine of  FIG. 1  for molding a bottle closure having a substantial T-shape in cross-section, such as a bottle closure for a liquor and condiment bottles requiring a T top closure, and showing a pair of removable pins for forming impressions on the ends of the bottle closure.  
         [0017]      FIG. 4  is end view of a removable pin of  FIG. 2  showing the negative impression of a logo.  
         [0018]      FIG. 5  is a side view of a T top closure of the present invention.  
         [0019]      FIG. 6  is a perspective view of a cylindrical closure of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]     Although this specification describes a particular type of plastic injection molding apparatus for manufacturing closures of the present invention, those skilled in the art will recognize that a wide variety of plastic injection molding machines can be used in the manufacture of these closures.  
         [0021]     Referring to the drawings, a mold apparatus  10  is shown including a mold unit  12 , a mold frame  14 , and a hydraulic piston  16  ( FIG. 1 ). The mold frame  14  consists of four cylindrical support bars  18  which are secured to a first plate  20  and to a second plate  22  by means of nuts  24 . A mold carriage  26  is slideably attached to the support bars  18  through bores which pass through the corners of the mold carriage  26 . Support blocks  28  are provided with bores and mounted to the corners of the mold carriage  26  to add extra support to the mold carriage  26  as it slides along the support bars  18 . A platen  30  is secured to the mold carriage  26  to evenly distribute force over the mold carriage  26 . Secured to the platen  30  is a piston ram  32 . The piston ram  32  passes through a bore in the center of the second plate  22  and is connected to a hydraulic cylinder  34 . The hydraulic cylinder  34 , piston ram  32 , traverse valve  92 , and volumetric variable hydraulic pump make up the hydraulic piston  16 . The hydraulic piston  16  is in connection with a central processing unit  74 , and can be controlled through the central processing unit  74 .  
         [0022]     A first mold section  36  is mounted to the first plate  20  in alignment with a second mold section  38  which is mounted to the mold carriage  26 . As the hydraulic piston  16  pushes the mold carriage  26  toward the first plate  20 , the first mold section  36  fits into seated engagement with the second mold section  38  to form a mold cavity  40  therebetween. The second mold section  38  has an ejector pin  168 , which is advanced after a plastic article has been formed to eject the article from the mold cavity. The ejector pin  168  can be moved hydraulically, pneumatically, electrically, servo-electrically, or by any other suitable or equivalent means.  
         [0023]     A nozzle inlet  44  is located in the center of the first plate  20  to allow an injection mixture  46  to pass into a mold inlet  48  located in the first mold section  36  and thereafter into the mold cavity  40 .  
         [0024]     Provided for operable engagement with the nozzle inlet  44  is an injection assembly  50  which prepares and injects the injection mixture  46  into the mold cavities  40  ( FIG. 1 ,  FIG. 2 ). The injection assembly  50  is provided with an injection barrel  52  supported by a main frame  54 . A nozzle unit  56  is mounted at one end of the injection barrel  52  and a hopper  58  is mounted to the top of the injection barrel  52 . Positioned coaxially within the injection barrel  52  is a reciprocating screw  60  with attached flights (not shown) for plasticizing and moving the injection mixture  46  toward the injection barrel  52  and nozzle unit  56 . A variable volume, pressure compensated hydraulic pump  62  is secured to the injection barrel  52  and operates to move the injection screw  60  relative to the injection barrel  52  during the injection molding process. The injection assembly  50  is provided with a large rotational motor  72  which turns the injection screw  60  to plasticize the injection mixture  46  before injection.  
         [0025]     The nozzle unit  56  is movable into and out of operative association with the nozzle inlet  44  upon a reciprocal movement of a carriage  64  relative to the main frame  54 . This reciprocal movement is responsive to the operation of a double acting cylinder  66  pivotally interconnected between the carriage  64  and the main frame  54 . The operation of the double acting cylinder  66  is controlled by a second linear transducer  68  mounted on the mainframe  54 .  
         [0026]     The injection assembly  50  is operably coupled to the central processing unit  74  which monitors the progress of the injection process and feeds back responsive information regarding this progress to the injection assembly  50  ( FIG. 1 ). In a preferred embodiment the central processing unit  74  is a personal computer, but the central processing unit  74  may, of course, be any system capable of receiving user input variables, monitoring the progress of a plastic injection run, and controlling the injection in response thereto. The central processing unit  74  is equipped with an input device  76  and a viewing screen  78 . To monitor the rate of injection mixture  46 , a shot size transducer  80  is coupled to the injection screw  60  to monitor the distance that the injection screw  60  travels. The shot size transducer  80  is a linear transducer which correlates movement of the injection screw  60  to a predetermined amount of the injection mixture  46  injected into the mold cavity  40 . The shot size transducer is connected to the central processing unit  74  in order to give feedback to the central processing unit  74 . As each incremental amount of the injection mixture  46  within the injection assembly  50  is injected into the mold cavity  40 , the shot size transducer  80  monitors the associated incremental movement of the injection screw  60 . Preferably the shot size transducer  80  measures increments of injection mixture  46  of one gram or less, which translates into approximately four thousand increments for a typical molding operation.  
         [0027]     To monitor the pressure at which the injection mixture  46  is injected into the mold cavity  40 , a pressure monitor  82  is operably coupled to the hydraulic pump  62  ( FIG. 1 ). The pressure monitor  82  is also coupled to the central processing unit  74 . The central processing unit  74  is operably coupled to an injection control  84  which is, in turn, coupled to the hydraulic pump  62  to manipulate the injection of the injection mixture  46 .  
         [0028]     At the beginning of the molding process the hydraulic piston  16  is actuated to force the piston ram  32  toward the first plate  20 . The platen  30  disburses the force of the piston ram  32  to the mold carriage  26  and the second mold section  38 . The second mold section  38  is moved into engagement with the first mold section  36  to form a mold cavity  40 .  
         [0029]     The injection mixture  46  may include a blowing agent mixed with a plastic injection material, as described in U.S. Pat. No. 6,139,934, the disclosure of which is incorporated herein by this reference. The injection mixture  46  is heated to an injection temperature and injected into the molding cavities  40 . The injection temperature is hot enough to plasticize the injection mixture  46 , and hot enough that the blowing agent will decompose, or be activated, unless the injection mixture  46  is pressurized. In the preferred embodiment the injection temperature is approximately 400 degrees Fahrenheit.  
         [0030]     Before the injection mixture  46  is injected into the mold cavity  40 , it is first plasticized to provide a flowable material which eventually hardens into a finished plastic article. The following parameters affect the plasticization process: the type of raw plastic material to be plasticized, throat temperature, the temperature of injection assembly heating zones, the size, length and type of screw  60 , the rate at which the screw  60  is turned, and the rate at which the screw  60  is allowed to move back.  
         [0031]     Like the plasticization process, the injection process is also controlled by the computer control program. The parameters associated with the injection process include the following: the type of raw injection mixture  46  to be injected; the temperature of the injection mixture  46 ; the size, length and type of screw  60 ; the rate at which the injection mixture  46  is injected; the mold design; and the mold temperature. Preferably, both the temperature of the injection mixture  46  and the rate at which the injection mixture  46  is injected are controlled by the computer control program. The computer control program also controls the movement of the ejector pin  168 .  
         [0032]     A common shape of bottle closures is the substantially cylindrical shape illustrated in  FIG. 3  generally at  200 . This type of closure is typically used in bottles of wine. It has a body member  202  that has a generally cylindrical surface and includes a pair of generally circular end portions  204  and  206 . In accordance with the present invention, it is desired to mold into one or both of the end portions  204 ,  206  markings which will be visible upon insertion of the closure  200  into a bottle. For this purpose, a negative impression of the markings have been formed in the face  208  of the ejector pin  168 . The face  208  has a pattern of raised areas, depressed areas, or combinations of both so that upon molding of the closure  200  in the mold cavity in contact with the face  208 , the “positive” form of the marking will be molded into an end portion of the closure  200 .  
         [0033]     The bottle closure  200  is commonly used by bottlers with bottling machinery which automatically insert the closures  200  into the necks of bottles. Since the closures  200  are symmetrical about a central transverse axis, they can be inserted either with end portion  204  facing the interior of the bottle and end portion  206  facing the exterior of the bottle or reversed wherein end portion  204  faces the exterior of the bottle and end portion  206  faces the interior of the bottle. Accordingly, it is desired that a face  210  of a sub gate pin  211  be releasably secured in the first mold section  32  so that both end portions of the closure  200  will carry the desired markings to ensure that the end portion that is visible outside of the bottle will always display the marking. Face  210  is formed with the same negative marking as face  208 , but is also provided with a small central opening  212  through which the plasticized injectable material can be introduced into the mold cavity. After the closure  200  has been molded and cooled sufficiently, the mold is opened and the closure  200  is ejected from the mold cavity  40  by the ejector pin  168  in the conventional manner.  
         [0034]     An alternative application of the closures of the present invention is to what is known in the industry as a “T top” an example of which is illustrated in  FIG. 5  generally at  300 . Closures  300  have a body member  302  that includes a pair of end portions  304  and  306  as well as a generally cylindrical surface  312  and an enlarged section  314 , thereby presenting a longitudinal cross section that is substantially T-shaped. Rather than being inserted fully into the neck of a bottle, closures  300  are inserted with only the smaller diameter surface  312  inside the neck of the bottle and the enlarged section  314  remaining outside the bottle and serving as a handle by which the closure  300  may be removed and reinserted into the bottle. In the prior art, the enlarged section  314  is molded of a hard, non-resilient plastic material and the smaller diameter section  312  is made of wood cork. In the present invention, the smaller diameter section  312  is molded of the resilient plastic material used for making of the closures  200 . As illustrated in  FIG. 3 , the enlarged diameter section  314  is inserted into the mold cavity and the smaller diameter section  312  is molded partially inside of it.  
         [0035]     According to the present invention, either or both end portions  304 ,  306  of the closure  300  may be formed with markings by the use of an ejector pin  168  and corresponding face  308  and a sub gate pin  311  and corresponding face  310 , which are sized to correspond to the size of the end portions  304  and  306 , respectively, but are otherwise as described previously with respect to the faces  208  and  210 . The faces  208 ,  210 ,  308 , and  310  are shown as being planar. The faces, however, can be either concave or convex in order to form a closure having a conversely shaped end portion. For example, the face  210  for use in forming the top end portion of a closure  200  may have a concave face on which the markings are formed and will thereby result in the formed closure having a raised or arched top.  
         [0036]     While the preferred embodiment of the invention herein described makes use of pins that may be easily and quickly swapped into and out of the mold cavity, the full concept of the invention includes forming the “negative” markings on disks that are releasably secured to the ends of the pins  168  and  211 .  
         [0037]     The foregoing description and drawings merely explain and illustrate the invention, and the invention is not limited thereto, except insofar as the claims are so limited as those skilled in the art who have the disclosure before them will be able to make modifications and variations therein without departing from the scope of the invention. For example, it is anticipated that the mold unit can be configured with more than one retractable mold portion thereby enabling the creation of several injection molded bottle closures at one time.