Abstract:
Disclosed herein is an ejector for an injection molding machine used to extract a molded product formed inside a die, the ejector including: a first ejector plate which is movably installed in a moving plate for fixing the die; a second ejector plate which is separably connected to the first ejector plate; and an ejector pin which is installed in at least one of the first and second ejector plates so as to push outward the molded product.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Korean Patent Application No. 10-2008-0083354, filed on Aug. 26, 2008, and all the benefits accruing therefrom under 35 U.S.C. §119, the contents of which in its entirety are herein incorporated by reference. 
     BACKGROUND 
     1. Field 
     This disclosure relates to an ejector for an injection molding machine, and more particularly, to an ejector for an injection molding machine which is installed in a moving plate so as to extract a molded product formed inside a die, and a moving plate including the same. 
     2. Description of the Related Art 
     An injection molding machine mainly includes an injection device and a clamping device, where the clamping device is used to carry out an operation of opening or closing a die, that is, a die opening operation and a die closing operation. When the die closing operation is completed by the clamping device, a molten material is injected into the die. At this time, the die is required to be strongly fastened so that the die is not opened by the high-pressure molten material. 
     Hereinafter, the structure of a known clamping device will be described with reference to the drawings. 
     As shown in  FIG. 1 , the known clamping device has a structure in which a fixed plate  110  and a moving plate  120  are disposed so as to face each other and a first die  111  and a second die  121  are respectively installed on facing surfaces of the fixed plate  110  and the moving plate  120 . The fixed plate  110  and the moving plate  120  are connected to each other via a tie bar  101 . 
     One end of the moving plate  120  is connected to a toggle link  140 . In detail, as shown in  FIG. 2 , the upper and lower ends of the rear surface of the moving plate  120  are provided with ribs  122 , and the upper end of each rib  122  is provided with a link hole  123 . A link pin  141  is attached into the link hole  123 , thereby connecting one end of the toggle link  140  to the link pin  141 . By means of a driving force of the toggle link  140 , the moving plate  120  moves forward or backward and the die fastening operation is carried out. 
     In addition, an extraction hole  124  is formed at the center portion of the moving plate  120 , and connection holes  125  are respectively formed at four corners thereof so as to allow the tie bar  101  to be inserted thereinto. An ejector  130  is installed in the extraction hole  124  so as to extract a molded product formed inside the die. 
     In the known clamping device having the above-described configuration, the moving plate  120  is configured to be movable forward and backward by the toggle link  140 . However, since the ribs  122  serving as portions used to be connected to the toggle link  140  are respectively provided in the upper and lower ends of the moving plate  120 , a problem arises in that a clamping force transmitted from the toggle link  140  is not uniformly transmitted to the whole surface of the moving plate  120  but is concentrated on the upper and lower ends of the moving plate  120 . 
     In order to solve the structural problem of the moving plate  120 , the structure of the moving plate may be modified into various forms. However, when the structure of the moving plate is modified, a problem arises in that the ejector installed in the known moving plate is not applied to the moving plate having a different structure. 
     This disclosure is contrived to solve the above-described problems, and is directed to providing a separable ejector for an injection molding machine which is applicable to even a moving plate having a modified structure and is easily assembled to the moving plate. 
     SUMMARY 
     In one aspect, there is provided an ejector for an injection molding machine used to extract a molded product formed inside a die, the ejector including: a first ejector plate which is movably installed in a moving plate for fixing the die; a second ejector plate which is separably connected to the first ejector plate; and an ejector pin which is installed in at least one of the first and second ejector plates so as to push outward the molded product. 
     Spacers may be installed between the first and second ejector plates. 
     The spacers may be integrally formed with an upper surface of the first ejector plate so as to have a gap between the spacers, and the second ejector plate may be coupled to upper portions of the spacers. 
     The first and second ejector plates may be formed in a bar shape extending in one direction, and the first and second ejector plates may be coupled to each other so as to intersect with each other. 
     The first or second ejector plate may be inserted into the guide pin so as to be movable in a vertical direction. 
     In another aspect, there is provided a moving plate equipped with an ejector used to extract a molded product formed inside a die, the moving plate including: a base plate which has the die installed in a lower surface thereof and a pin hole formed therein; a frame which is installed above the base plate and has an opening formed at the center thereof; a first ejector plate which is located in a space formed between the base plate and the frame and is movably installed therein; a second ejector plate which is located inside the opening of the frame and is separably connected to an upper portion of the first ejector plate; and an ejector pin which is installed in at least one of the first and second ejector plates so as to pass through the pin hole. 
     A sectional area of the frame may gradually decrease in a direction toward the base plate. 
     A guide pin may be installed in the frame and the base plate in a fixed manner, and the first or second ejector plate may be inserted into the guide pin. 
     Since the ejector disclosed herein is separated into at least two or more parts, the ejector is applicable to even a moving plate having a modified structure. Particularly, the ejector is easily assembled to a center-press-type moving plate capable of transmitting a clamping force to a central surface of a die, thereby concentrating a clamping force, transmitted from a toggle link, on the center of the moving plate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features and advantages of the disclosed exemplary embodiments will be more apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a side sectional view showing a known clamping device; 
         FIG. 2  is a perspective view showing a known moving plate; 
         FIG. 3  is a perspective view showing a moving plate equipped with an ejector according to an embodiment; 
         FIG. 4  is a sectional view showing the combined moving plate equipped with the ejector according to the embodiment; 
         FIG. 5  is an enlarged perspective view showing the ejector in  FIG. 3 ; 
         FIG. 6  is a perspective view showing the combined ejector in  FIG. 5 ; and 
         FIG. 7  is a sectional view showing the operated moving plate equipped with the ejector according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth therein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art. In the description, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the presented embodiments. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, the use of the terms a, an, etc. does not denote a limitation of quantity, but rather denotes the presence of at least one of the referenced item. The use of the terms “first”, “second”, and the like does not imply any particular order, but they are included to identify individual elements. Moreover, the use of the terms first, second, etc. does not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. It will be further understood that the terms “comprises” and/or “comprising”, or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     In the drawings, like reference numerals in the drawings denote like elements. The shape, size and regions, and the like, of the drawing may be exaggerated for clarity. 
     Hereinafter, a moving plate equipped with an ejector according to an embodiment will be described in detail with reference to the accompanying drawings. 
       FIG. 3  is a perspective view showing the detached moving plate equipped with the ejector according to an embodiment.  FIG. 4  is a sectional view showing the combined moving plate equipped with the ejector according to the embodiment. For the convenience of description, an ejector pin is not shown in  FIGS. 3 and 4 . 
     As shown in  FIGS. 3 and 4 , a moving plate  200  according to the embodiment includes a base plate  210  which has a die installed therebelow, a frame  220  which is formed above the base plate  210 , and an ejector  300  which extracts a molded product formed inside the die. 
     Connection holes  211  are respectively formed at four corners of the base plate  210  so as to allow a tie bar ( 101  shown in  FIG. 1 ) to pass therethrough, and a plurality of pin holes  212  are formed at the center of the base plate  210 . The frame  220  is installed above the base plate  210  which has an opening  221  formed at the center thereof. Ribs  222  are respectively formed in the upper and lower portions of the frame  220  in a protruding manner so as to have a gap therebetween, the rib  222  being used for the connection operation to a toggle link ( 140  shown in  FIG. 1 ). Each of the ribs  222  is provided with a link hole  223 . The toggle link  140  and the rib  222  are connected to each other by a connection pin. 
     Side-face openings  224  are respectively formed on both side lower surfaces of the frame  220 . Accordingly, a space is defined between both side lower surfaces of the frame  220  and the upper surface of the base plate  210 . In addition, a sectional area of the frame  220  gradually decreases in a direction from the rib  222  to the base plate  210 . Accordingly, a clamping force transmitted from the toggle link is concentrated on the center of the moving plate  200 . 
     A plurality of guide pins  226  are installed in the base plate  210  and the frame  220  in a fixed manner so as to have a gap therebetween. 
     The ejector  300  includes a first ejector plate  310  and a second ejector plate  320  which are separable from each other. The first ejector plate  310  is disposed between the base plate  210  and the frame  220  via the side-face openings  224  of the frame  220 . The second ejector plate  320  is inserted in the guide pins  226  so as to move to the inside of the opening  221  of the frame  220 . In addition, the second ejector plate  320  is coupled to the first ejector plate  310  while being disposed thereabove. 
       FIG. 5  is an enlarged perspective view showing the ejector in  FIG. 3 .  FIG. 6  is a perspective view showing the combined ejector in  FIG. 5 . 
     The first ejector plate  310  is formed in a bar shape extending in one direction, and has a pair of spacers  330  disposed on the upper surface thereof so as to maintain a gap between the first ejector plate  310  and the second ejector plate  320 . The upper surface of each spacer  330  is provided with coupling holes  331  which are used for the coupling operation to the second ejector plate  320 . 
     A plurality of ejector pins  340  are installed on the lower surface of the first ejector plate  310 . 
     The second ejector plate  320  is formed so as to extend in a direction intersecting with the first ejector plate  310 . The second ejector plate  320  is provided with a plurality of guide holes  321  which allow the guide pins  226  to be inserted thereinto. Slots  322  are respectively formed at the positions corresponding to the coupling holes  331  of the spacers  330 . Screws (not shown) are respectively fastened to the coupling holes  331  of the spacer  330  via the slots  322 , thereby coupling the first ejector plate  310  to the second ejector plate  320 . 
     The first ejector plate  310  and the second ejector plate  320  are coupled to each other so as to form a cross shape, and the ejector pins  340  may be installed at various positions corresponding to the shape of the ejector. 
     The ejector  300  according to the embodiment is separated into two parts, but the disclosure is not limited thereto. For example, the ejector  300  may be separated into three or more parts. In addition, in the embodiment, the ejector pins  340  are installed in only the first ejector plate  310 , but the disclosure is not limited thereto. For example, the ejector pins  340  may be installed on the lower surface of the second ejector plate  320 . 
     The second ejector plate  320  is connected to a known driving unit (not shown) so as to be movable in a vertical direction. Accordingly, the molded product formed inside the die is extracted in such a manner that the ejector  300  moves along the guide pins  226  in a vertical direction by operating the driving unit. 
       FIG. 7  is a sectional view showing the operated moving plate equipped with the ejector according to the embodiment. As shown in  FIG. 7 , when the ejector  300  moves down by a distance L along the guide pins  226 , the ejector pins  340  protrude from the lower surface of the base plate  210  so as to push outward the molded product formed inside the die. 
     As described above, since the ejector according to the embodiment is separated into two or more parts, it is advantageous in that the ejector according to the embodiment is more conveniently applied to the moving plates having various structures compared with an ejector with a single part. 
     While the exemplary embodiments have been shown and described, it will be understood by those skilled in the art that various changes in form and details may be made thereto without departing from the spirit and scope of this disclosure as defined by the appended claims. 
     In addition, many modifications can be made to adapt a particular situation or material to the teachings of this disclosure without departing from the essential scope thereof. Therefore, it is intended that this disclosure not be limited to the particular exemplary embodiments disclosed as the best mode contemplated for carrying out this disclosure, but that this disclosure will include all embodiments falling within the scope of the appended claims.