Abstract:
An injection molding machine includes a clamping unit constructed for support of at least two molding tools to provide at least two different cavities. A first plasticizing unit is provided for charging one of the cavities in one of the molding tools, and a second plasticizing unit is provided for charging the other one of the cavities in the other one of the molding tools. The second plasticizing unit is hereby attached to a mounting in a substantially vertical orientation. The mounting may be mounted on one of the platens of the injection molding machine or on a frame which extends above the clamping unit.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a division of prior filed U.S. application Ser. No. 11/748,535, filed May 15, 2007, now U.S. Pat. No. 7,484,948, the priority of which is hereby claimed under 35 U.S.C. §120, which in turn is a continuation of prior filed copending PCT International application no. PCT/EP2005/055920, filed Nov. 11, 2005, which designated the United States and has been published but not in English as International Publication No. WO 2006/056539 A1 and on which priority is claimed under 35 U.S.C. §120 and which claims the priority of German Patent Application, Serial No. 10 2004 057 164.3, filed Nov. 26, 2004, pursuant to 35 U.S.C. 119(a)-(d), the contents of which are incorporated herein by reference in its entirety as if fully set forth herein. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates, in general, to the field of injection molding machines. 
     Nothing in the following discussion of the state of the art is to be construed as an admission of prior art. 
     A typical injection molding machine includes a clamping unit for support of at least two molding tools to provide at least two different cavities for production of multicomponent products. The clamping unit may be constructed as a stack mold or include an intermediate plate in the form of a sliding plate or a swivel plate. As a result, the overall injection molding machine is of drawn-out construction whose footprint is substantial. Examples of such injection molding machines include German Offenlegungsschriften DE 199 37 200 and DE 101 38 087. 
     It would therefore be desirable and advantageous to provide an improved injection molding machine to obviate prior art shortcomings 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, an injection molding machine includes a clamping unit constructed for support of at least two molding tools to provide at least two different cavities, a first plasticizing unit for charging one of the cavities in one of the molding tools, a second plasticizing unit for charging the other one of the cavities in the other one of the molding tools, a mounting for attachment of the second plasticizing unit in a substantially vertical orientation, and at least two platens, wherein the mounting is secured to one of the platens. 
     According to another aspect of the present invention, an injection molding machine includes a clamping unit constructed for support of at least two molding tools to provide at least two different cavities, a first plasticizing unit for charging one of the cavities in one of the molding tools, a second plasticizing unit for charging the other one of the cavities in the other one of the molding tools, a mounting for attachment of the second plasticizing unit in a substantially vertical orientation, and a frame disposed above the clamping unit, said mounting being secured to the frame. 
     The present invention resolves prior art problems by orienting one of the plasticizing units in a substantially vertical direction. In order to be clear on this point, it is to be understood that the term “substantially vertical direction” includes a positioning of the one plasticizing unit at an angle ranging from about 45° to 90°. In other words, the benefits of the invention can be realized even though the axis of the plasticizing unit is not coincidental with the vertical but rather may be slanted up to an angle of about 45° in relation to the vertical. 
     The clamping unit may be constructed as a stack mold or include an intermediate plate. In the latter case, the intermediate plate is positioned between the platens, with one of the molding tools being disposed between the intermediate plate and one of the platens, and the other one of the molding tools being disposed between the intermediate plate and the other one of the platens. The intermediate plate may be constructed for movement in a linear direction and/or rotation. When the intermediate plate is constructed for rotation, the use of a swivel plate with clocked reversal becomes also possible. 
     According to another feature of the present invention, the mounting and the second plasticizing unit can be constructed and positioned such that the plasticizing cylinder of the second plasticizing unit is arranged at an end face outside of the clamping unit, and a melt deflection device may be provided which is connected or connectable to the second plasticizing unit for introduction of plastic melt, produced by the second plasticizing unit, into the associated one of the cavities. 
     According to another feature of the present invention, the frame for attachment of the mounting may be supported, at least in part, on a machine bed. It is, of course, also conceivable to support the frame on the ground or any level surface on which the machine bed is placed. The frame may envelope the entire clamping unit or only part thereof. 
     According to another feature of the present invention, the mounting may be arranged on the frame for linear movement in opening and closing directions of the clamping unit. As a result, the position of the injection unit can be adjusted for different molding tools. Suitably, the frame supports two guide rails extending in parallel relationship in a longitudinal direction of the clamping unit for guiding the mounting in linear direction. 
     According to another feature of the present invention, the second plasticizing unit may be arranged on the mounting for up and down movements. As a result, the clamping unit can be retracted in relation to the molding tool as well as to the melt deflection device. 
     According to another feature of the present invention, one of the platens may be fixed and the other one of the platens may be mobile. It is, of course, also conceivable to construct both platens for mobility. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which: 
         FIG. 1  is a schematic perspective view of a first embodiment of an injection molding machine according to the present invention; 
         FIG. 2  is a schematic side view of the injection molding machine of  FIG. 1 ; 
         FIG. 3  is a schematic top view of the injection molding machine of  FIG. 1 ; 
         FIG. 4  is a schematic perspective view of a second embodiment of an injection molding machine according to the present invention; 
         FIG. 5  is a schematic side view of the injection molding machine of  FIG. 4 ; 
         FIG. 6  is a sectional view of the injection molding machine of  FIG. 4 ; and 
         FIG. 7  is a schematic top view of the injection molding machine of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way. It should also be understood that the figures are not necessarily to scale and that the embodiments are sometimes illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted. 
     Turning now to the drawing, and in particular to  FIG. 1 , there is shown a schematic perspective view of a first embodiment of an injection molding machine according to the present invention, including a clamping unit, generally designated by reference numeral  12  and mounted onto a machine bed  10 . The injection molding machine includes an unillustrated first plasticizing unit which is positioned to the right of the clamping unit  12 , and a second plasticizing unit, generally designated by reference numeral  32  and described in more detail hereinafter. 
     The clamping unit  12  includes a fixed platen  14  which is supported on the machine bed  10  and a moving platen  16  which is movable back and forth along unlabeled rails on the machine bed  10 . A swivel plate arrangement with a swivel plate  22  and a drive for the swivel plate  22  is arranged between the platens  14 ,  16 , as clearly shown in  FIG. 2 . Although not shown in the drawings, the swivel plate  22  is also operated by a separate drive for back-and-forth movement in opening and closing directions of the clamping unit  12 . The swivel plate  22 , which constitutes an intermediate plate and has a generally block-shaped configuration, carries on all four sides of the block parts of a molding tool  24 . Through incremental turning of the swivel plate  22  by 90°, the individual parts of the molding tools can be successively exchanged. 
     As shown in particular in  FIGS. 2 and 3 , the fixed platen  14  carries a part of a molding tool  26 , and the moving platen  16  carries a part of a molding tool  27 . In a closed position of the clamping unit  12 , the molding tool parts  26 ,  27  form with the molding tool parts  24  a first cavity (half-mold  24  and half mold  26 ) as well as a second cavity (half-mold  24  and half mold  27 ). The clamping pressure between both platens  14 ,  16  with in-between swivel platen  22  is realized in a manner known per se via tie bars and a hydraulic clamping unit for applying the clamping pressure. 
     As shown in  FIGS. 1-3 , the second plasticizing unit  32  is arranged on the moving platen  16  in a vertical disposition. A mounting  30  is hereby secured to the top of the platen  16  for attachment of the plasticizing unit  32  which has a plasticizing cylinder  34  situated at the end face of the mounting outside of the clamping unit  12 . In other words, the plasticizing cylinder  34  is situated outside of the moving platen  16  at a distance thereto. 
     A melt deflection device  36  is mounted to the moving platen  16  and extends there through to port into the cavity of the closed molding tools  24 ,  27 . The plasticizing cylinder  34  can be connected to the melt deflection device  36  so that melt produced in the plasticizing unit  32  can be introduced via the melt deflection device  36  into the cavity. Although not shown in the drawings, it will be understood by persons skilled in the art that the melt deflection device  36  may, of course, include further elements, such as a hot runner or a nozzle shut-off device. 
     The injection molding machine, described in  FIGS. 1-3 , is of compact configuration, even when used with a swivel plate type clamping unit for the production of multicomponent products. 
     Referring now to  FIG. 4 , there is shown a schematic perspective view of a second embodiment of an injection molding machine according to the present invention. In the following description, parts corresponding with those in  FIGS. 1-3  will be identified, where appropriate for the understanding of the invention, by corresponding reference numerals, each increased by “100”. The injection molding machine of  FIG. 4  includes a clamping unit  112  which is mounted onto a machine bed  110 . To the right of the clamping unit is the first plasticizing unit  111  which is positioned outside of the fixed platen  114 . In addition to the fixed platen  114 , the clamping unit  112  includes a moving platen  116 , with the fixed and moving platens  114 ,  116  being interconnected by four tie bars  118 . The clamping pressure is generated by hydraulic cylinders  120  through intervention of the tie bars  118 . A swivel plate  122  is positioned between the platens  114 ,  116  for attachment of molding tools  124 . The molding tools  124  interact with complementary molding tools  126 ,  127  in a manner as described with reference to the injection molding machine of  FIGS. 1-3 . 
     In the embodiment of the injection molding machine of  FIGS. 4-7 , the second plasticizing unit  132  is secured to a mounting  142  which is connected to a frame  140 . The frame  140  extends essentially over the clamping unit  112  and is supported on one end by two uprights  143  behind the moving platen  116  and on the other end by the fixed platen  114 . Mounted to the topside of the frame  140  are two guide rails  141  which extend in spaced-apart parallel relationship longitudinally in the direction of the clamping unit  112 . The mounting  142  is guided along the guide rails  141  for linear movement. 
     The second plasticizing unit  132  includes a plasticizing cylinder  134  and two hydraulic cylinders  133  for realizing up and down movements of the plasticizing cylinder  134 . 
     Depending on the dimension of the molding tools  124 ,  126 ,  127 , the plasticizing unit  132  can be positioned precisely and accurately in relation to an injection opening by the movable mounting  142 . The capability to move up and down enables the plasticizing unit  132  to move downwards, when the molding tool is closed, for injection of melt into the cavity. The plasticizing unit  132  moves up again, before the molding tool is opened. 
     The injection molding machine of  FIGS. 4-7  has overall also a relatively small footprint and requires thus little space. 
     While the invention has been illustrated and described in connection with currently preferred embodiments shown and described in detail, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. The embodiments were chosen and described in order to best explain the principles of the invention and practical application to thereby enable a person skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.