Abstract:
A flexible plate system for a hot runner assembly includes a backing plate; a manifold plate detachably connected to the backing plate; a manifold positioned between the backing plate and the manifold plate and having at least one nozzle associated therewith; and wherein the manifold plate has at least one plate slot that allows the nozzle to extend through the manifold plate and having at least a first lateral dimension substantially larger than the outside diameter of the nozzle.

Description:
CROSS REFERENCES 
       [0001]    None. 
       TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to the field of injection molding equipment and, more particularly, to an improved hot runner mounting system. 
       BACKGROUND OF THE INVENTION 
       [0003]    Hot runner manifold systems are utilized to transfer molten material, typically plastic resin, from an injection molding machine to a mold. Hot runner manifold systems typically include a manifold plate, a manifold housed in the manifold plate, and a backing plate that supports the manifold and manifold plate. The manifold system routes molten material from a central sprue, which connects to an injection unit on an injection molding machine, to a plurality of nozzles which inject the molten material into cavities in the mold. The manifold system divides the flow of the molten material into several branches as it flows from the central sprue to the nozzles. 
         [0004]    Referring to  FIGS. 1 and 2 , a prior art manifold system using two plates is shown with portions of the plates and main manifold cut away to reveal internal detail. A manifold assembly  10  is located between a manifold plate  12  and a backing plate  14 . Sprue  16  connects to the manifold  10  at a central location. Manifold  10  has one or more melt channels  18  that communicate the molten material from the manifold  10  to nozzles (not shown) connected to the manifold  10 . 
         [0005]    One limitation of these prior art systems is that the backing plate  14  and manifold plate  12 , in addition to the manifold  10 , must be replaced each time a new hot runner system is desired. While the need for new manifolds and nozzles is largely unavoidable, the possibility of reusable plates represents a significant potential cost and time saving benefit. Even though the backing and manifold plates add relatively little value to a hot runner system relative to the manifolds and nozzles, these parts can represent as much as 30-40% of the cost of a new hot runner system 
         [0006]    Therefore, it would be desirable to provide a hot runner plate system that is reusable with new or modified manifolds and nozzles. 
         [0007]    The present invention is directed to meeting one or more of the above-stated desirable objectives. 
       SUMMARY OF THE INVENTION 
       [0008]    One aspect of the present invention is to provide a hot runner plate system that may be reused with new or modified manifold(s) and nozzles in a different configuration. 
         [0009]    In accordance with the above aspects of the invention, there is provided a flexible plate system for a hot runner assembly that includes a backing plate; a manifold plate detachably connected to the backing plate; a mold manifold positioned between the backing plate and the manifold plate and having at least one nozzle associated therewith; and wherein the manifold plate has at least one plate slot that allows the nozzle to extend through the manifold plate and having at least a first lateral dimension substantially larger than the outside diameter of the nozzle. 
         [0010]    In an another embodiment, the manifold plate has a plurality of dowel holes located along the perimeter of the plate slot to accommodate dowels for positive location of the nozzle relative to the plate slot. 
         [0011]    These aspects are merely illustrative of the various aspects associated with the present invention and should not be deemed as limiting in any manner. These and other objects, aspects, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the referenced drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Reference is now made to the drawings which illustrate the best known mode of carrying out the invention and wherein the same reference numerals indicate the same or similar parts throughout the several views. 
           [0013]      FIG. 1  is a plan view of a prior art hot runner system showing the manifold plate and nozzles extending therethrough. 
           [0014]      FIG. 2  is a cross sectional view of the prior art hot runner system shown in  FIG. 1 . 
           [0015]      FIG. 3  is a plan view of a hot runner system according to one embodiment of the present invention showing the manifold plate and nozzles extending therethrough. 
           [0016]      FIG. 4  is a cross-sectional view of the hot runner system of  FIG. 3 . 
           [0017]      FIG. 5  is a top view of a manifold plate according to an embodiment of the present invention. 
           [0018]      FIG. 6  is a cross sectional view of a hot runner system according to an alternate embodiment of the present invention. 
           [0019]      FIG. 7  is a bottom view of a manifold plate according to another embodiment of the present invention. 
           [0020]      FIG. 8  is a bottom view of a manifold plate according to another embodiment of the present invention. 
           [0021]      FIG. 9  is a cross sectional view of a system according to another embodiment of the present invention. 
           [0022]      FIG. 10  is a cross sectional view of a system according to yet another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. For example, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention. 
         [0024]      FIGS. 3-8  illustrate the overall arrangement of a first embodiment of an improved hot runner injection molding system. The device includes a mold manifold  110 , having manifold melt channel  112  through which molten material reaches injection nozzles  114 . The mold manifold  110  is surrounded and supported by a backing plate  116  and a manifold plate  118 . The mold manifold  110  is, in effect, “sandwiched” between the backing plate  116  and manifold plate  118 . 
         [0025]    While  FIGS. 3-8  illustrate one embodiment, in some cases either the manifold plate  118  or the backing plate  116  may be considered to be part of the mold assembly rather than the hot runner assembly. A shown in  FIG. 9 , the manifold  300  and nozzles  302  may be located in a hot runner manifold plate  304  that is either inserted or mounted to the mold plates (not shown) with the backing plate  306  taking the form of a mold plate (considered as part of the mold rather the hot runner). In another embodiment, illustrated in  FIG. 10 , the backing plate is eliminated and a machine platen  308  is used to contain the hot runner system. Those of skill in the art will appreciate that the present invention is equally suitable for use with any of these different structural arrangements. 
         [0026]    The central sprue  120  delivers melt to the mold manifold  110 . Melt then passes through a series of melt channels  112  within the mold manifold  110  to the injection nozzles  114 , where it is delivered to each gate of the mold (not shown). 
         [0027]    As can be seen most clearly in  FIG. 4 , each injection nozzle  114  protrudes through and extends out of the manifold plate  118 . In prior art hot runner systems, as shown in  FIGS. 1 and 2 , a plate bore  22  is provided in the manifold plate  16  to accommodate each nozzle  22 . These plate bores  22  are sized to match, with some clearance, the outside diameter of the nozzles  22 . In the improved system disclosed herein, the manifold plate  118  is provided with plate slots  124 . In one embodiment, these plate slots  124  are provided with a first lateral dimension—the width—that matches, again, with some clearance, the outside diameter of the nozzles  114 . However, the plate slots  124  are provided with a second lateral dimension—the length—significantly longer than the diameter of the nozzles  114  such that the nozzles may be positioned in multiple locations along that slot length, thus providing the desired positioning flexibility. The length of the plate slots  124  may utilize any number of dimensions and is limited only by the nozzle configuration used in the hot runner system and thermal considerations. 
         [0028]    While an elongated slot has been previously described, it is contemplated as being within the scope of the present invention to use expanded openings in a variety of configurations.  FIGS. 7 and 8  illustrate a number of non-limiting examples including multi-leg slots  202 , and L-shaped slots  204 . Thus, the term “plate slots” is intended to be non-limiting as to the shape of the enlarged opening contemplated by the present invention. The rounded ends or corners of such shapes obviously being intended to accommodate the rounded diameter of the nozzles. 
         [0029]    It is typical in hot runner systems for dowels  126  to be used to position the mold manifold  110 , and consequently the nozzles  114 , relative to the manifold plate  118 . These dowels  126  are frequently positioned between nozzles such that they do not directly relate to the plate bores or in the case of the present invention, plate slots. However, in an alternate embodiment of the present invention illustrated in  FIG. 5 , an additional multi-position positive locating mechanism may be incorporated in the plate slots  124  previously described. In one version of this embodiment, a plurality of dowel holes  128  are provided along the perimeter of the plate slots  124  to accommodate additional dowels  130  associated with each individual injection nozzle  114 . The plurality of dowel holes  128  allow positive locating of the nozzles  114  relative to the plate slots in the multiple positions within the plate slots  124 . 
         [0030]    In another version of this embodiment, screws  132  are utilized as the positioning device rather than dowels. In this version, screw through holes  134  are positioned along the perimeter of the plate slots  124 , and the screws  132  are inserted into those holes  134  from the outside of the manifold plate  118  and into a threaded hole (not shown) associated with each nozzle  114 . 
         [0031]    Other objects, features and advantages of the present invention will be apparent to those skilled in the art. While preferred embodiments of the present invention have been illustrated and described, this has been by way of illustration and the invention should not be limited except as required by the scope of the appended claims and their equivalents.