Abstract:
An injection molding apparatus has a manifold and a plurality of first and second adjustable manifold blocks. The second manifold blocks are in fluid communication and are directly connected to a hot runner nozzle. The second manifold blocks are coupled to the first manifold blocks via connector devices. These connector devices contain a melt channel and allow the second manifold blocks and therefore the hot runner nozzles to be rotated relative to the first manifold blocks around at least two axes. This allows the nozzles to be positioned in front of mold gates that are located at variable elevations with respect to the manifold.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the benefit under 35 U.S.C. § 119(e) of provisional U.S. Appl. No. 60/479,907 filed Jun. 20, 2003, the content of which is incorporated by reference herein in its entirety. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates generally to an injection molding apparatus and, in particular, to a non-linear multi-cavity injection molding apparatus having several position and or angle adjustable manifold blocks and nozzles.  
           [0004]    2. Related Art  
           [0005]    Injection molding systems may be made out of a single block or single piece manifold and this may be called a unitary manifold. Also the injection molding systems are in some instances made out of a manifold assembly that includes several identical or almost identical manifold blocks that are connected or linked between them in several ways. These multi block manifolds do not include means to vary the angular position between the manifold blocks and thus the angular position of the nozzles coupled to these manifolds cannot be adjusted.  
           [0006]    Injection molding is being used to make larger and larger components, particularly in the automotive industry. In addition to considerably increasing the size of the melt channel and the length of the nozzles, this has led to the use of systems in which several nozzles extend from an elongated manifold made of a single manifold block or several manifold blocks to a single mold cavity. Further, the part shapes are often complex which requires the mold gates that delimit the mold cavity to be located at varying heights and angles relative to the manifold.  
           [0007]    In order to accommodate multiple nozzles extending at different angles relative to the manifold, a high level of tooling accuracy in the mold is necessary. In some applications, nozzles were simply bolted at different angles into place on a side of the manifold. Some of these known solutions typically included manifolds and nozzles that were custom designed for each application, which had the further disadvantage that set up was often difficult and time consuming.  
         SUMMARY OF THE INVENTION  
         [0008]    According to an embodiment of the present invention there is provided an injection molding apparatus including a first manifold block having a first manifold melt channel for receiving a melt stream of moldable material from a source, a second manifold block having a second manifold melt channel for receiving the melt stream from the first manifold melt channel, and a nozzle coupled to an outlet of the second manifold block. The nozzle includes a nozzle channel for receiving the melt stream from the second manifold melt channel. The nozzle channel communicates with a mold cavity for receiving the melt stream from the nozzle through a mold gate. A connector assembly couples the first manifold block to the second manifold block. The connector assembly includes a melt channel for allowing melt to flow between the first manifold melt channel and the second manifold melt channel. The angle of the second manifold block is adjustable together with the nozzle relative to the first manifold block.  
           [0009]    According to another embodiment of the invention, the distance between the second manifold block and the first manifold block can be adjusted via a slidable connection that allows the nozzle to accurately reach the mold gates and compensate for the thermal expansion.  
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0010]    Embodiments of the present invention will now be described more fully with reference to the accompanying drawings in which like reference numerals indicate similar structure.  
         [0011]    [0011]FIG. 1 is an exploded isometric view of portions of an injection molding apparatus according to an embodiment of the present invention.  
         [0012]    [0012]FIG. 2 is a side sectional view of the apparatus of FIG. 1 in a mold.  
         [0013]    [0013]FIG. 3 is a sectional plan view of a portion of FIG. 2.  
         [0014]    [0014]FIG. 4 is an isometric view of portions of an injection molding apparatus according to another embodiment of the present invention.  
         [0015]    [0015]FIG. 5 is a side sectional view of the apparatus of FIG. 4 in a mold.  
         [0016]    [0016]FIG. 6 is an exploded isometric view of portions of an injection molding apparatus according to another embodiment of the present invention.  
         [0017]    [0017]FIG. 7 is side sectional view of an embodiment of the present invention including a plurality of nozzles, manifold blocks, and connection assemblies. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    Referring now to FIGS. 1 and 2, an injection molding apparatus  10  includes a manifold  12 , a first manifold block  16  and a second manifold block  44 . A valve gated nozzle  56  is coupled to the second manifold block  44 . A connector assembly  70 , which will be described in detail later, is provided to couple the second manifold block  44  to the first manifold block  16 .  
         [0019]    The manifold  12  includes a manifold melt channel  11  for receiving a melt stream of moldable material from a melt source (not shown) through an inlet thereof (not shown). The manifold  12  further includes an outlet  14  for delivering the melt stream to the first manifold block  16 . Manifold  12  further includes a pair of opposed and semi-circular slots  13   a  and  13   b  through which screws  15   a  and  15   b  extend, respectively, to connect manifold  12  to first manifold block  16 . By slightly unscrewing screws  15   a  and  15   b  with respect to the upper surface of slots  13   a  and  13   b , first manifold block  16  may be rotated relative to manifold  12  about an axis  17 .  
         [0020]    The first manifold block  16  includes a first manifold melt channel  18  having an inlet  20 . The inlet  20  is aligned with the outlet  14  of the manifold melt channel  11  to receive the melt stream therefrom. A locating bushing  38  is provided between the first manifold block  16  and the manifold  12  to locate the parts relative to one another. The first manifold block  16  is further located relative to a mold plate  40  by a locating ring  36 . First manifold block  16  is coupled to mold plate  40  through rod  19 .  
         [0021]    The first manifold block  16  includes a cut-out portion  26  that is provided in a side  28  thereof, as seen in FIG. 1, for example. The cut-out portion  26  includes a first wall  30  that is offset from the side  28  and a pair of second walls  32 ,  34  that extend generally perpendicular to the first wall  30 . An outlet  22  of the first manifold melt channel  18  is provided in the second wall  34 .  
         [0022]    As shown in FIG. 3, the first manifold melt channel  18  of the first manifold block  16  includes a bend  24  that is provided between the inlet  20  and the outlet  22  thereof. The bend  24  allows the melt stream to enter a connector assembly  70  (a portion of which is shown in FIG. 3), as described in detail below, from a side thereof.  
         [0023]    The connector assembly  70  includes a first connector  72  and a second connector  74 . The first connector  72  includes a melt channel  76  having an inlet portion  80  and an outlet portion  82 . The inlet portion  80  is aligned with a first axis  84  and the outlet portion  82  is aligned with a second axis  86 , which is generally perpendicular to the first axis  84 . The inlet portion  80  of the first connector  72  is coupled to the outlet  22  of the first manifold melt channel  18  by a bushing  88 . The bushing  88  allows the first connector  72  to rotate relative to the first manifold block  16  about the first axis  84 .  
         [0024]    A locking device  92  extends through second wall  32  of the first manifold block  16  to engage a seat  90 , which is provided in the first connector  72 , opposite the inlet portion  80 . The locking device  92  includes an aperture  94  that is shaped to receive a tool. By locking the locking device  92 , rotation of the first connector  72  relative to the first manifold block  16  is prevented.  
         [0025]    The second connector  74  is generally a bushing having a first end  96 , a second end  98  and a melt channel  78  extending therethrough. The first end  96  includes a reduced diameter portion  100 , which is received in the outlet portion  82  of the melt channel  76 . An outer cylindrical surface  102  of the reduced diameter portion  100  is generally smooth to allow for relative rotation about the second axis  86  between the first connector  72  and the second connector  74 . The smooth connection also allows for relative sliding due to thermal expansion between the first connector  72  and the second connector  74 .  
         [0026]    The second manifold block  44  includes a threaded recess  50  that is provided in a side  52  thereof for receiving the second connector  74 , which is generally a bushing. The second end  98  of the second connector  74  is threaded in order to mate with the threaded recess  50 . The second connector  74  further includes an enlarged hexagonal shaped portion  104 , which is engagable by a tool.  
         [0027]    It will be appreciated by persons skilled in the art that the second connector  74  could be coupled to the second manifold block  44  in an alternative manner. Further, the second connector  74  could be integral with the second manifold block  44 .  
         [0028]    The second connector  74  is aligned with a second manifold melt channel  46 , which extends through the second manifold block  44 . An outlet  48  of the second manifold melt channel  46  is aligned with a nozzle channel  58  of the nozzle  56 . The nozzle channel  58  communicates with a mold cavity  64  through a mold gate  66 . The mold gate  66  is selectively openable by valve pin  60 , which extends through the nozzle channel  58 . The valve pin  60  is actuable by a self-supporting actuating mechanism  62 , which is described in U.S. Pat. No. 4,979,892 to Gellert, the contents of which are herein incorporated by reference in its entirety.  
         [0029]    The first and second manifold blocks  16 ,  44 , and nozzle  56  are heated by heating elements  42 ,  54 , and  57 , respectively. A thermocouple  55  is also provided to monitor the temperature of the melt stream in the nozzle channel  58 . Manifold  12  is also heated by a heating element (not shown).  
         [0030]    Operation of the injection molding apparatus  10  according to the present invention will now generally be described. During installation, the locking device  92  of the first connector  72  is loosened and the first connector  72  is rotated about the first axis  84  until the desired angle between the first manifold block  16  and the second manifold block  44  is reached. Once the desired angle has been reached, the locking device  92  is locked.  
         [0031]    The second manifold block  44  rotates and slides freely about the second axis  86 . The second manifold block  44  is thus positioned relative to the mold gate  66  without locking it into place. This allows for the distance and angle between the first manifold block  16  and the second manifold block  44  to be constantly adjustable in order to maintain good nozzle-gate alignment and accommodate thermal expansion.  
         [0032]    Once the components have been adjusted to suit the particular molding application, the injection molding apparatus is heated to an operating temperature and the melt stream flows under pressure through the manifold melt channel  11  of the manifold  12  and into first manifold melt channel  18  of the first manifold block  16 . From the first manifold melt channel  18 , the melt flows into the melt channel  76  of the first connector  72  of the connector assembly  70  and into the melt channel  78  of the second connector  74 . From the connector assembly  70 , the melt stream continues to flow through the second manifold melt channel  46  and into the nozzle channels  58  of a plurality of nozzles  56 . The melt stream then flows past the mold gates  66  and into the mold cavities  64 . The mold cavities  64  are then cooled by the coolant flowing through cooling ducts (not shown) in the mold plate  40 . Once a predetermined amount of time has elapsed, the molded parts are ejected from the mold cavities  64 .  
         [0033]    In a second embodiment, the second manifold block  44  is connected directly to the manifold  12 . In this arrangement, the manifold  12  receives the second connector  74  and the first connector  72  is coupled to the second manifold block  44 .  
         [0034]    Referring now to FIGS. 4 and 5, another embodiment of an injection molding apparatus  10   a  is generally shown in which like reference numerals indicate like parts. The injection molding apparatus  10   a  is similar to the injection molding apparatus  10  shown FIGS. 1-3, however, nozzle  56   a  is not valve gated. Instead, the nozzle  56   a  is thermal gated. Thermal gated nozzles are well known in the art and therefore will not be described further herein.  
         [0035]    With the exception of the nozzle  56   a , all of the parts of the injection molding apparatus  10   a  are generally identical to those of the injection molding apparatus  10 , and therefore will not be described.  
         [0036]    Referring now to FIG. 6, another embodiment of injection molding apparatus  10   b  is generally shown in which like reference numerals indicate like parts. The injection molding apparatus is similar to the injection molding apparatus  10  shown in FIGS. 1-3 however; connector assembly  70   b  is comprised of three connectors. The first two portions of the connector assembly  70   b  are identical to connector assembly  70  shown in injection molding apparatus  10 , however the second end  98  of the second connector  74  is threaded in order to mate with the threaded recess  50   b  located in a third connector  72   b  which is identical to the first connector  72 . The third connector  72   b  is mated with the second manifold block  44  in the same manner as the first connector  72  and the first manifold block  16 . This embodiment allows for an additional rotation of the second manifold block about an axis  85 .  
         [0037]    [0037]FIG. 7 shows the environment in which the invention described above is generally used. FIG. 7 shows manifold  12  including a manifold melt channel  11 . A plurality of first manifold blocks  16  are coupled to manifold  12  such that the first manifold melt channel  18  of each is aligned with the outlets  14  of the manifold  12 . Coupled to each first manifold block  16  is a connector assembly  70  and second manifold block  44 , and a nozzle  56 / 56   a , as described in detail above. It would be recognized by those skilled in the art that the variations discussed above with respect to the embodiments can be applied FIG. 7, without deviating from the spirit and scope of the invention.  
         [0038]    The many features and advantages of the invention are apparent from the detailed specification and, thus, it is intended by the appended claims to cover all such features and advantages of the invention that fall within the true spirit and scope of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.