Abstract:
The present invention relates to a cavity and a core changeable foam-forming mold. According to a preferred embodiment of the present invention, the cavity and the core changeable foam-forming mold, comprises: a fixing mold; a mobile mold which is horizontally moved in the direction of the fixing mold and is combined with the fixing mold for coupling with a forming machine; one or more cavities which are detachably coupled with one side of the mobile mold facing the fixing mold; one or more cores which are detachably coupled with one side of the fixing mold facing the mobile mold; a raw material injection unit which is provided at the mobile mold and supplies a raw material for a molded product into a forming space formed among the cavity; and an extraction unit which is provided at the mobile mold.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a cavity and core changing type foam-forming mold, and more particularly to a cavity and core changing type foam-forming mold, which can change a cavity and a core according to the specification of a product to be molded. 
         [0003]    2. Description of the Prior Art 
         [0004]    In general, an expanded poly-propylene (EPP) or expanded polystyrene (EPS) product forming mold forms an EPP or EPS product of a predetermined shape by fusing EPP or EPS grains filled in a molding space of the EPP or EPS product forming mold using high-pressure steam. 
         [0005]    Since the EPP or EPS product is more environment-friendly than a material such as urethane, it has been widely used for a handle, particularly, a rim, mounted in a vehicle, a sun visor for a vehicle, and the like. 
         [0006]    Referring to  FIG. 1 , an EPP or EPS product forming mold in the related art includes a fixed mold  10  and a movable mold  20 . 
         [0007]    The fixed mold  10  is composed of a fixed base plate  12 , a fixed frame  14  coupled to one side surface of the fixed base plate  12 , and a core  16  coupled to one side of the fixed frame  14 . 
         [0008]    The movable mold  20  is provided in symmetry with the fixed mold  10  so that the movable mold  20  moves toward the fixed mold  10  and is assembled with the fixed mold  10 . The movable mold  20  includes a movable base plate  22 , a movable frame  24  coupled to one side surface of the movable base plate  22 , and a cavity  26  coupled to one side of the movable frame  24 . 
         [0009]    Here, a raw material injector  28  for supplying raw materials into a molding space that is formed between the cavity  26  and the core  16  is installed in a predetermined position of the one side surface of the movable base plate  22 , and at least one ejecting tool  30  is installed to be apart for a predetermined distance from the raw material injector  28  to take away a molded product that is molded in the molding space from the cavity  26 . 
         [0010]    In addition, a plurality of cooling water supply nozzles  32 , which are connected to a cooling water supply tube (not illustrated), are provided in predetermined positions of the inner surfaces of the fixed base plate  12  and the movable base plate  22 . 
         [0011]    However, as described above, the EPP or EPS product forming mold in the related art is constructed in a manner that the cavity  26  and the core  16 , which actually form the product, are integrally provided on the movable frame  20  and the fixed frame  10 , or bolted to the insides of the movable frame  20  and the fixed frame  10 , respectively, and thus if a product to be molded is changed, it is usual to replace the movable mold  20  and the fixed mold  10 , which are heavy and voluminous. In the case of replacing only the cavity  26  and the core  16  to simplify the replacement, it is required to separate the fixed base plate  12  and the movable base plate  22  from each other and then to separate the cavity  26  and the core  16 , which are bolted to the insides of the fixed frame  14  and the movable frame  24 , from each other. Accordingly, the mold replacement time is increased, and thus the workability and productivity are lowered. 
         [0012]    Further, since the fixed mold  10  and the movable mold  20  are separately manufactured according to the specification of the product, the mold manufacturing cost is increased, and a large number of fixed molds  10  and movable molds  20 , which are heavy and voluminous, should be kept and managed to lower the utility of a factory site. 
       SUMMARY OF THE INVENTION 
       [0013]    Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art while advantages achieved by the prior art are maintained intact. 
         [0014]    One subject to be achieved by the invention is to provide a cavity and core changing type foam-forming mold, which enables only a cavity and a core to be changed according to the specification of a product to be molded to prevent the lowering of the workability and productivity according to the mold replacement, reduces the mold manufacturing cost since it is not required to manufacture the mold by specifications, and improves the utility of the factory site according to the custody of the molds. 
         [0015]    In one aspect of the present invention, there is provided a cavity and core changing type foam-forming mold having a fixed mold and a movable mold that is horizontally transported in the direction of the fixed mold and is assembled with the fixed mold to be attached to and to be detached from a molding machine, which includes one or more cavities detachably coupled to one side surface of the movable mold that faces the fixed mold; one or more cores detachably coupled to one side surface of the fixed mold that faces the movable mold; a raw material injector installed on the movable mold to supply a raw material of a molded product into a molding space that is formed between the cavity and the core when the movable mold and the fixed mold are combined; and an ejection means installed on the movable mold to separate the molded product molded in the molding space from the cavity. 
         [0016]    The movable mold may include a movable plate having at least one cavity fastening hole formed thereon to make the cavity detachable, a support plate provided to be spaced apart for a predetermined distance from the movable plate, and a plurality of support bars supporting the movable plate and the support plate to be spaced apart from each other, wherein a stepped portion is formed on one side surface of a border of the cavity fastening hole along the circumferential direction so that the cavity is coupled to one side surface of the movable mold that faces the fixed mold, and the fixed mold has a fixed plate having at least one core fastening hole formed thereon to make the core detachable, and a stepped portion is formed on one side surface of a border of the core fastening hole along the circumferential direction so that the core is coupled to one side surface of the fixed mold that faces the movable mold. 
         [0017]    The cavity and core changing type foam-forming mold according to an embodiment of the present invention may further include one or more fastening portions formed in a predetermined position on an opposite surface of the molding space of the cavity, and a support having one end that is coupled to the one or more fastening portions and the other end that is in contact with a predetermined position on an inner side surface of the support plate. 
         [0018]    The cavity and core changing type foam-forming mold according to an embodiment of the present invention may further include one or more fastening portions formed in a predetermined position on an opposite surface of the molding space of the core, and a support having one end that is coupled to the one or more fastening portions and the other end that is in contact with a predetermined position on an inner wall on a fixing side of the molding machine. 
         [0019]    A plurality of supports may be provided, and the neighboring supports are connected by a support connection bar to be spaced apart from each other. 
         [0020]    At least one support portion may be formed to project from a predetermined position on one side surface of the support plate and the predetermined position on the inner wall on the fixing side of the molding machine to support the other end portion of the support. 
         [0021]    The raw material injector may include a body having a raw material inlet port and an air inlet port, a connection pipe in which two large and small pipes are screw-engaged with a front end portion of the body to form an air transport space portion, a nozzle coupled to a front end portion of the connection pipe, a piston rod penetratingly coupled to a rear end portion of the body to perform a reciprocating motion within the body, and a piston coupled to a front end portion of the piston rod to open/close the nozzle according to a movement direction of the piston rod. 
         [0022]    The ejection means may include an ejector pin elastically and movably inserted into the inside of the piston rod, a support member penetratingly coupled to a circumferential surface of the ejector pin and placed on an end portion of the piston rod, a fixing member coupled to a locking groove that is formed on one end portion of the ejector pin, and a coil spring inserted into the circumferential surface of the ejector pin and having one end portion and the other end portion elastically supported in the support member and the fixing member, respectively. 
         [0023]    According to the present invention having the above-described construction, since only the cavity and the core, in which the shape of the molded product to be molded is formed, can be replaced from the movable mold and the fixed mold, mold replacement according to the change of the specification of the molded product is not required, and thus the workability and productivity are improved. 
         [0024]    Further, the cavity and the core, which are formed with similar sizes and shapes, can be used together in a set of molds, and thus it is not required to manufacture molds by specifications of a molded product to be molded. Accordingly, the mold investment cost can be saved, and the number of molds to be manufactured can be reduced to improve the utility of the factory site. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0026]      FIG. 1  is a cross-sectional view schematically illustrating a mold in the related art; 
           [0027]      FIG. 2  is a perspective view of a movable mold according to a preferred embodiment of the present invention; 
           [0028]      FIG. 3  is a perspective view of a fixed mold according to a preferred embodiment of the present invention; 
           [0029]      FIG. 4  is an exploded perspective view of a movable mold illustrated in  FIG. 2 ; 
           [0030]      FIG. 5  is an exploded perspective view of a fixed mold illustrated in  FIG. 3 ; 
           [0031]      FIG. 6  is a cross-sectional view taken along line I-I illustrated in  FIG. 2 ; 
           [0032]      FIG. 7  is a cross-sectional view taken along line II-II illustrated in  FIG. 3 ; 
           [0033]      FIG. 8  is a cross-sectional view of a raw material injector illustrated in  FIG. 4 ; and 
           [0034]      FIG. 9  is a cross-sectional view schematically illustrating a cavity and core changing type foam-forming mold according to a preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0035]    Hereinafter, a cavity and core changing type foam-forming mold according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings. 
         [0036]      FIG. 2  is a perspective view of a movable mold according to a preferred embodiment of the present invention, and  FIG. 3  is a perspective view of a fixed mold according to a preferred embodiment of the present invention.  FIG. 4  is an exploded perspective view of a movable mold illustrated in  FIG. 2 , and  FIG. 5  is an exploded perspective view of a fixed mold illustrated in  FIG. 3 .  FIG. 6  is a cross-sectional view taken along line I-I illustrated in  FIG. 2 ,  FIG. 7  is a cross-sectional view taken along line II-II illustrated in  FIG. 3 , and  FIG. 8  is a cross-sectional view of a raw material injector illustrated in  FIG. 4 .  FIG. 9  is a cross-sectional view schematically illustrating a cavity and core changing type foam-forming mold according to a preferred embodiment of the present invention. 
         [0037]    Referring to  FIGS. 2 to 9 , a cavity and core changing type foam-forming mold according to an embodiment of the present invention includes a fixed mold  200  coupled to an inner wall on the fixing side of a molding machine, a movable mold  100  that is coupled to an inner wall on a moving side of the molding machine, and is horizontally transported in the direction of the fixed mold  200  to be assembled with the fixed mold  200 , one or more cavities  102  detachably coupled to one side surface of the movable mold  100  that faces the fixed mold  200 ; one or more cores  202  detachably coupled to one side surface of the fixed mold  200  that faces the movable mold  100 ; a raw material injector  140  supplying a raw material of a molded product into a molding space that is formed between the cavity  102  and the core  202  when the movable mold  100  and the fixed mold  200  are combined; and an ejection means  150  separating the molded product molded in the molding space from the cavity  102 . 
         [0038]    The movable mold  100  is movably mounted on the moving side of the molding machine (not illustrated) to reciprocate in the horizontal direction by power being supplied from an outside. As illustrated in  FIGS. 2 and 4 , the movable mold  100  includes a movable plate  110 , a support plate  120  provided to be spaced apart for a predetermined distance from the movable plate  110 , and a plurality of support bars  130  supporting the movable plate  110  and the support plate  120  to be spaced apart from each other. 
         [0039]    The movable plate  100  is in a rectangular plate shape, and has at least one cavity fastening hole  112 . A cavity  102  to be described later is detachably coupled to the cavity fastening hole  112 . 
         [0040]    The cavity  102  is formed to have a shape of a product to be molded, and forms a molding space through coupling to the core  202  that is detachably coupled to the fixed mold  200  when the movable mold  100  is transported in the horizontal direction and is combined with the fixed mold  200  to be described later. 
         [0041]    Here, a stepped portion  114  is formed on one side surface of a border of the cavity fastening hole  112  along the circumferential direction so that the cavity  102  is detachably coupled to one side surface of the movable mold  100  that faces the fixed mold  200  by a bolt  116 . 
         [0042]    Further, referring to  FIG. 6 , in a predetermined position on one side surface of the cavity  102 , that is, on an opposite surface of the molding space that is formed through coupling of the cavity  102  to the core  202  to be described later, one or more fastening portions  104  are formed to project, and a female screw portion  104   a  with a predetermined depth is formed in the center of the inside of the fastening portion  104  so that a male screw portion  106   a  that is formed on one end portion of the support  106  to be described later is screw-engaged with the female screw portion  104   a.    
         [0043]    Further, in the predetermined position on one side surface of the cavity  102 , a raw material supply hole  108  is formed so that a raw material can be easily supplied from a raw material injector  140  to the molding space that is formed through coupling of the cavity  102  to the core  202  to be described later. 
         [0044]    The support  106  is in a cylinder shape, and the male screw portion  106   a  is formed to project from one end portion of the support  106  so that the male screw portion  106   a  is screw-engaged with the female screw  104   a.    
         [0045]    The male screw portion  106   a  formed on one end portion of the support  106  is screw-engaged with the fastening portion  104  formed on a predetermined position on one side surface of the cavity  102 , and the other end portion of the support  106  is in contact with a predetermined position on one side surface of the support plate  120  to support the cavity  102  so that the cavity  102  is prevented from being damaged by the pressure. 
         [0046]    As described above, according to an embodiment of the present invention, the fastening portion  104  and the support  106  are screw-engaged with each other. However, it is also possible that a locking groove (not illustrated) is formed in the center of the inside of the fastening portion  104 , and a locking bar (not illustrated) is formed to project from one end portion of the support  106 , so that the fastening portion  104  and the support  106  are shrink-fitted to each other. 
         [0047]    Further, referring to  FIG. 6 , one or plural supports  106  may be provided, and the neighboring supports  106  are connected together by a support connection bar  109  so that the neighboring supports  106  are spaced apart from each other. 
         [0048]    The support plate  120  is in a rectangular plate shape, and is provided to be apart for a predetermined distance from the movable plate  110 . 
         [0049]    Here, between the movable plate  110  and the support plate  120 , a plurality of support bars  130  are provided to make the movable plate  110  and the support plate  120  spaced apart from each other. 
         [0050]    Further, on a predetermined position on one side surface of the support plate  120 , at least one support  122  is formed to project. That is, referring to  FIGS. 6 and 9 , the support  122  is formed to project from the predetermined position on the one side surface of the support plate  120  that is in contact with the other end portion of the support  106 , and if the other end portion of the support  106  becomes in contact with the predetermined position on the one side surface of the support plate  120 , the lower end portion of the support  106  is supported by the support portion  122  to prevent the support  106  from drooping due to its weight. 
         [0051]    The raw material injector  140  includes a body  142  having a raw material inlet port  142   a  and an air inlet port  142   b , a connection pipe  144  in which two large and small pipes  144   a  and  144   b  are screw-engaged with a front end portion of the body  142  to form an air transport space portion  144   c , a nozzle  146  coupled to a front end portion of the connection pipe  144 , a piston rod  148  penetratingly coupled to a rear end portion of the body  142  to perform a reciprocating motion within the body  142 , and a piston  149  coupled to a front end portion of the piston rod  148  to open/close the nozzle  146  according to a movement direction of the piston rod  148 . 
         [0052]    The raw material injector  140  as constructed above is penetratingly coupled to the predetermined position on one side surface of the support plate  120  of the movable mold  100 , and the nozzle  146  of the raw material injector  140  is inserted into and coupled to the raw material supply hole  108  that is formed in the predetermined position on the one side surface of the cavity  102  to supply a raw material to the molding space that is formed through combination of the cavity  102  and the core  202 . 
         [0053]    The ejection means  150  includes an ejector pin  152  elastically and movably inserted into the inside of the piston rod  148 , a support member  154  penetratingly coupled to a circumferential surface of the ejector pin  152  and placed on an end portion of the piston rod  148 , a fixing member  158  coupled to a locking groove  156  that is formed with a predetermined depth in a predetermined position of one end portion of the ejector pin  152  along the circumferential direction, and a coil spring  160  inserted into the circumferential surface of the ejector pin  152  and having one end portion and the other end portion elastically supported in the support member  154  and the fixing member  158 , respectively. 
         [0054]    That is, after the raw material from the raw material injector  140  is injected into the molding space that is formed between the cavity  102  and the core  202  when the movable mold  100  and the fixed mold  200  are combined together and a molded product is molded, the ejector means  150  operates the movable mold  100  to separate the movable mold  100  from the fixed mold  200 , and the end portion of the ejector pin  152  becomes in contact with the one side surface of the inside of the molding machine when the movable mold  100  moves toward the one side surface of the inside of the molding machine. At the same time, the ejector pin  152  elastically moves inside the raw material injector  140 , and the other end portion of the ejector pin  152  penetratingly projects through the nozzle  146  to push the molded product in the inside of the cavity  102 , so that the molded product is separated from the cavity  102 . 
         [0055]    On the other hand, the fixed mold  200  is fixedly mounted onto the fixing side of the molding machine (not illustrated), and is combined with the movable mold  100  to correspond to the movable mold  100 . 
         [0056]    Referring to  FIG. 5 , the fixed mold  200  is provided with a fixed plate  210  in a rectangular plate shape, at lest one core fastening hole  212  is provided on the fixed plate  210 , and the core  202  is detachably coupled to the core fastening hole  212 . 
         [0057]    The core  202  is inserted into the inside of the cavity  102  to mold the product to be molded, and has a shape that corresponds to the cavity  102 . 
         [0058]    Here, on one side surface of a border of the core fastening hole  212 , a stepped portion  214  is formed along the circumferential direction so that the core  202  is detachably coupled to one side surface of the fixed mold  200  that faces the movable mold  100  through a bolt  116 . 
         [0059]    In general, the core  202  that is provided on the fixed mold  200  has a complicated shape, which may be slightly deformed by gas pressure, and thus the support  106  provided on the cavity  102  is unnecessary. However, if the shape of the core is exceptionally large, one or more fastening portions are formed in the predetermined position on the one side surface of the core  202 , that is, although not illustrated in the drawing, on an opposite surface of the molding space that is formed through combination of the core  202  and the cavity  102 , and the support is coupled to the fastening portion. 
         [0060]    Here, as described above, one end portion of the support is coupled to the fastening portion, and the other end portion thereof becomes in contact with the predetermined position of the inner wall on the fixing side of the molding machine to prevent the core  202  from being damaged by the pressure during molding. 
         [0061]    Further, at least one support portion (not illustrated) is formed to project from the predetermined position of the inner wall on the fixing side of the molding machine, and if the other end portion of the support becomes in contact with the predetermined position of the inner wall on the fixing side of the molding machine, the lower end portion of the support is supported by the support portion to prevent the support from drooping due to its weight. 
         [0062]    Hereinafter, features of the cavity and core changing type foam-forming mold as constructed above according to an embodiment of the present invention will be described. 
         [0063]    First, in the case of molding a product with a changed specification of the product, the molding machine is first stopped, and the cavity  102  and the core  202 , which are coupled by a plurality of bolts  116  to the cavity fastening hole  112  of the movable mold  100  and the core fastening hole  212  of the fixed mold  200 , respectively, are separated from each other. 
         [0064]    Then, the cavity  102  and the core  202 , on which the shape of the product is formed, are placed in the cavity fastening hole  112  and the core fastening hole  212 , respectively, and then fastened by the bolts  116  to complete the coupling. 
         [0065]    Accordingly, it is not required to replace the movable mold  100  and the fixed mold  200 , in which the cavity  102  and the core  202  are integrally formed according to the change of the specification of the product to be molded, and thus the lowering of the productivity due to the inconvenience, personnel expenses, and the increase of the replacement time, which occur in replacing the whole molds, can be solved. 
         [0066]    Further, since the movable mold  100  and the fixed mold  200  are manufactured by specifications of the product to be molded, the mold investment cost can be reduced, and the utility of a factory site, which is required to manufacture and keep the molds by specifications of the products, can be improved. 
         [0067]    Although preferred embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.