Patent Abstract:
A valve device is configured for obturating an opening of a channel defined in an injection molding device. The valve device includes a plug movably received in the channel, and a resilient member connected with the plug. The plug includes an obturating portion for obturating the opening of the channel. The resilient member is configured for driving the plug to its original position where the obturating portion obturates the opening, after the opening of the channel is opened.

Full Description:
Relevant subject matter is disclosed in the co-pending U.S. patent applications (application Ser. No. 11/956,345, and entitled “INJECTION MOLDING DEVICE;” application Ser. No. 11/956,347, and entitled “METHOD FOR ELONGATING FOIL;” application Ser. No. 11/956,348, and entitled “METHOD FOR MANUFACTURING A FOIL DECORATED MOLDING;” application Ser. No. 11/956,350, and entitled “INJECTION MOLDING DEVICE”), which are filed on the same date Dec. 14, 2007. 
   BACKGROUND 
   1. Field of the Invention 
   The present invention relates to valve devices, and particularly to a valve device of an injection molding device for manufacturing a foil decorated molding. 
   2. Description of Related Art 
   Conventionally, various kinds of methods for manufacturing a foil decorated molding, which is molded by an injection molding process and has a transfer layer removed from a substrate foil of a transfer foil and placed on the surface of the molding after the transfer foil is inserted into cavities in an injection mold, have been known in the art. Since the use of the method requires an alignment of the transfer foil along a cavity-forming face of the mold, the transfer foil is preheated before the injection molding process so as to be easily aligned along the cavity-forming face of the mold where the cavity-forming face thereof is greatly recessed or projected from a parting face of the mold. 
   A traditional injection molding method includes transferring a heater between the male mold and the female mold to heat the foil before matching the molds, and removing the heater after the foil is heated. However, because of the need for the heater and the space it occupies, cost and volume of the injection mold is increased. A new method is used for elongating the foil between the male and female mold by exhausting air from a cavity via the female mold and pressurizing the foil by inputting thermal medium to cause the foil to cling to an inner surface of the cavity of the female mold. However, in this method, the thermal medium cannot be controlled. 
   What is needed is to provide a valve device for controlling supply of a thermal medium to an injection molding device. 
   SUMMARY 
   In one embodiment, a valve device is configured for obturating an opening of a channel defined in an injection molding device. The valve device includes a plug movably received in the channel, and a resilient member connected to the plug. The plug includes an obturating portion for obturating the opening of the channel. The resilient member is configured for driving the plug to its original position where the obturating portion obturates the opening, after the opening of the channel is opened. 
   Other advantages and novel features of the present invention will become more apparent from the following detailed description of an embodiment when taken in conjunction with the accompanying drawings, in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross-sectional view of an injection molding device having a valve device in accordance with an embodiment of the present invention, together with a foil, the injection molding device including a male mold and a female mold; 
       FIG. 2  is a cross-sectional view of the female mold, similar to  FIG. 1 ; 
       FIGS. 3 and 4  are enlarged, partially cutaway views of the male mold of  FIG. 1 , showing two using states respectively; 
       FIG. 5  is a cross-sectional view of the female mold of  FIG. 1 , but showing the foil extending into the cavity of the female mold; 
       FIG. 6  is similar to  FIG. 1 , but showing the foil extending along an inner surface of the cavity of the female mold and the male and female molds matched together; 
       FIG. 7  is similar to  FIG. 6 , but showing a state after injection; and 
       FIGS. 8 and 9  are enlarged, partially cutaway views of the male mold in accordance with another embodiment of the present invention, showing two using states respectively. 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , an injection molding device in accordance with an embodiment of the present invention includes a transport  10  for transporting a foil  100 , a mold including a male mold  20  and a female mold  30 , a plurality of pressing members  40 , and a thermal medium source  90 . 
   The male mold  20  has a projecting part  21  protruding toward the female mold  30 . A plurality of air discharging holes  23  is defined in the male mold  20  around the projecting part  21  and extending from a side, facing the female mold  30 , of the male mold  20  to an opposite side of the male mold  20 . A pressure release valve  80  is connected to each air discharging hole  23 . The pressure release valve  80  is adjustable according to need during molding. A plurality of receiving slots  25  is defined in the male mold  20  in vicinity of edges of the male mold  20 . A plurality of hermetic rings  27  is received in the corresponding receiving slots  25 . 
   Referring also to  FIG. 2 , the female mold  30  defines a cavity  31  therein. The cavity  31  includes a bottom surface A 2 , a first side surface A 1  extending from an edge of the bottom surface A 2 , and a second side surface A 3  extending from an opposite edge of the bottom surface A 2  to a surface that faces the male mold  20 , with an opening formed on the corresponding surface of the female mold  30 . A length of the opening of the cavity  31  is L. A plurality of air discharging holes  32  is defined in the male mold  20  and extending from a side, facing the male mold  20 , of the female mold  30  to an opposite side of the female mold  30 . At least one of the air discharging holes  32  extends from the bottom surface A 2  of the cavity  31  to the corresponding side of the female mold  30  opposite to the male mold  20 . Each air discharging hole  32  is connected to a vacuum-pump at the side of the female mold  30  opposite to the male mold  20 . A plurality of hermetic rings  33  is attached to the female mold  30  adjacent to an edge of the female mold  30 . 
   Referring also to  FIGS. 3 and 4 , the male mold  20  defines a plurality of channels  29  therein extending from a side, facing the female mold  30 , of the projecting part  21  to a side of the male mold  20  opposite to the female mold  30 . Each channel  29  includes a bell-mouthed recessed portion  291  defined in the projecting part  21  facing the female mold  30 , of the projecting part  21 , a conduit  295  defined in the male mold  20  communicating with a small end of the recessed portion  291 , and an L-shaped slender duct  296  with one end communicating with the conduit  295  and the other end passing through the surface opposite to the female mold  30 , of the male mold  20 . A block  298  protrudes in from one end opposite to the recessed portion  291 , of the conduit  295 . One end of a pipe  91  is connected to the end opposite to the female mold  30 , of each slender duct  296 , and the other end of the pipe  91  is connected to the thermal medium source  90 . A through hole is defined in the block  298 . 
   A valve device is arranged in each channel  29 . In this embodiment, the valve device includes a plug  70  attached in each channel  29 . The plug  70  includes a taper-shaped obturating portion  71  for obturating the recessed portion  291  of the channel  29 , and a pole  73  extending from a small end of the obturating portion  71 . The pole  73  extends through the through hole of the block  298 . A fastening member  75  is fixed to a distal end of the pole  73 . A resilient member  79 , such as a spring, fits about the pole  73  and is resiliently located between the block  298  and the fastening member  75 . 
   The thermal medium source  90  has thermal medium contained therein, such as thermal liquid or high-pressure gas. In this embodiment, the thermal medium is thermal high-pressure gas. The thermal medium is capable of being heated by an electric heater or an infrared ray heater (IR heater). 
   The transport  10  includes two transporting rollers  13  and two guiding rollers  15  positioned at two opposite ends of the mold respectively, for transporting the foil  100  into the mold. The foil  100  includes a base layer, and a printed layer attached to the base layer and having printed decorations. 
   Referring also to  FIGS. 5 and 6 , the foil  100  is transported into the mold and between the male and female mold  20 ,  30 . The male and female mold  20 ,  30  are with the pressing members  40  locked together to form a molding space among the inner surface of the cavity  31  of the female mold  30 , the projecting portion  21  of the male mold  20 , and parts around the projecting portion  21 . The pressing members  40  are received in the corresponding receiving slots  25 , and press the corresponding hermetic rings  27 ,  33  to airproof the molding space. The molding space is separated into a first airproof space adjacent to the female mold  30  and a second airproof space adjacent to the male mold  20  by the foil  100 . A vacuum is connected to the air discharging holes  32  of the female mold  30  to vacuumize the first airproof space, thus the foil  100  is sucked toward the first airproof space. The pressure release valve  80  is shut, and the value of the pressure release valve  80  is predetermined according to the molding condition. The thermal medium source  90  inputs heated gas to the channels  29  via the pipes  91 . The plugs  70  are driven by the heated gas to move toward the female mold  30 , therefore the channels  29  open. The heated gas is blown into the second airproof space to press and shape the foil  100  to cling to the inner surface of the cavity  31  of the female mold  30 . The foil  100  is intenerated by the heated gas to cling to the inner surface of the cavity  31  easily. 
   Referring also to  FIG. 7 , molten resin is injected through an injection opening defined in the male mold  20  into the molding space. The molten resin presses the plugs  70  into the corresponding channels  29  against resistance of the corresponding resilient members  79 . The heated gas in the second airproof space is released via the air discharging holes  23  of the male mold  20  when the pressure in the molding space is greater than the predetermined value of the pressure release valve  80 . The molten resin is cooled to form a mold body. The mold is opened, with the male mold  20  being separated from the female mold  30 . The base layer of the foil  100  is released from the mold body. Thus, the printed layer of the foil  100  is attached to a surface of the mold body. 
   In this embodiment, the injection molding device is used for elongating the foil  100  between the male and female mold  20 ,  30  by exhausting air from the cavity  31  via the air discharge holes  32  of the female mold  30  and pressurizing the foil  100  via the heated gas. For example, a length of the first side surface A 1  is a 1 , a length of the second side surface A 2  is a 2 , and a length of the bottom surface A 3  is a 3 , when the first, second, and bottom surface A 1 , A 2 , A 3  of the cavity  31  and the length L accord with an expression a 1 +a 2 +a 3 &gt;=(1+20%)*L, the foil  100  is capable of being elongated for suiting the cavity  31  of the female mold  30 . 
   Referring also to  FIGS. 8 and 9 , in another embodiment, the valve device includes a plug  70   a  attached in each channel  29 . The plug  70   a  includes a taper-shaped obturating portion  71   a  for obturating the recessed portion  291  of the channel  29 , and a pole  73   a  extending from a small end of the obturating portion  71   a . A hook  74   a  is formed on one end of the pole  73   a  away from the obturating portion  71   a . A resilient member  79   a  is arranged between the hook  74   a  and one end of the channel  29  away from the recessed portion  291 . Two slender ducts  296   a  are defined in the male mold  20  each with one end communicating with the end of the channel  29  away from the recessed portion  291  and the other end passing through the surface opposite to the female mold  30 , of the male mold  20 . The end opposite to the female mold  30 , of each slender duct  296   a , is connected to the thermal medium source  90  via a pipe  91 . 
   It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

Technology Classification (CPC): 1