Patent Abstract:
A mold releasing method for releasing a core member from a mold includes steps of: a) providing a supporting member and arranging the supporting member on the mold, the supporting member comprising a base and a number of sidewalls extending from the base to the mold, a through hole being defined in the substrate and co-axially aligned with the core member; b) providing a bolt, the bolt comprising a threaded rod extending through the through hole of the substrate and threadedly engaged with the core member; and c) rotating the bolt to move the core member to disengage from the mold.

Full Description:
BACKGROUND 
     1. Field of the Invention 
     The present invention generally relates to a mold releasing device, and particularly to a mold releasing method. 
     2. Description of Related Art 
     Injection molding processes are widely used for manufacturing workpieces, for example, optical articles such as lenses, light guide plates or other. The injection molding method has advantages such as high production rate and efficiency, and cost of optical elements thereby can be reduced. 
     In an injection molding process of the related art, a mold is utilized for forming the workpiece. The mold typically includes a first mold part and a second mold part. Each of the first and second mold parts has a core member. Both of the core members have a molding surface conforming to a surface of the workpiece. When the first and second mold parts are brought together, a mold chamber according to a size of the workpiece is defined between the two molding surfaces of the core members. Generally, when the size, such as a thickness of the workpiece requires an adjustment, the core members of the mold need to be pulled apart from the mold to be replaced, or to be disassembled and then modified. However, pulling apart the core members directly may lead to problems for the mold such as abrasion and loss of concentricity, as a result, a service life of the mold is shortened and quality of the workpiece formed using such a mold is reduced also. 
     Therefore, a mold releasing method is desired for overcoming the described limitations. 
     SUMMARY 
     In accordance with the present embodiment, a mold releasing method for releasing a core member from a mold includes steps of: a) providing a supporting member and arranging the supporting member on the mold, the supporting member comprising a base and a number of sidewalls extending from the base to the mold, a through hole being defined in the substrate and co-axially aligned with the core member; b) providing a bolt, the bolt comprising a threaded rod extending through the through hole of the substrate and threadedly engaged with the core member; and c) rotating the bolt to move the core member to disengage from the mold. 
     Other advantages and novel features of the present invention will be drawn from the following detailed description of a preferred embodiment of the present invention with attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a mold releasing device arranged on a mold. 
         FIG. 2  shows the mold releasing device engaging with the mold core of the mold. 
         FIG. 3  shows the mold releasing device releasing a mold core of the mold. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A detailed explanation of a mold releasing device according to an exemplary embodiment will now be made with reference to the drawings attached hereto. The mold releasing device is configured for releasing a core member of a mold. 
     As shown in  FIG. 1 , the mold includes a mold base  4  and a core member  5 . The mold base  4  defines a mounting hole  41  therein. The mounting hole  41  extends through the mold base  4 , and includes an upper portion  42  and a lower portion  43 . The upper portion  42  of the mounting hole  41  has a diameter greater than that of the lower portion  43 , i.e., the mold base  4  has a relatively large inner diameter at an upper portion, and a relatively small inner diameter at a lower portion thereof. Thus a step (not labeled) is formed at an inner surface of the mold base  4 . The core member  5 , which can be a member such as an insert, is received in the mounting hole  41  of the mold base  4 . The core member  5  includes an upper portion  51  arranged on the step of the mold base  4  with a diameter being approximately the same as the diameter of the upper portion  42  of the mounting hole  41 , and a lower portion  53  with a diameter being approximately the same as the diameter of the lower portion  43  of the mounting hole  41 . The lower portion  53  of the core member  5  forms a molding surface  55  at a distal end thereof. A tapped blind hole  52  is defined in a center of the upper portion  51  of the core member  5  with inner thread  54  formed therein. The tapped blind hole  52  is co-axially aligned with the mounting hole  41  of the mold base  4 . A depth of the tapped blind hole  52  of the core member  5  is less than a height of the core member  5 , and is greater than a height of the lower portion  53  of the core member  5 . 
     The mold releasing device includes a supporting member  1 , a bolt  2  and a washer  3 . The supporting member  1  includes a substrate  11  and a pair of sidewalls  13 . The substrate  11  is elongated and rectangular. A through hole  12  is defined in a center of the substrate  1 . The sidewalls  13  extend downwardly from two opposite sides of the substrate  11 , respectively. A distance between the sidewalls  13  of the supporting member  1  is greater than the diameter of the upper portion  51  of the core member  5 , and the supporting member  1  is arranged on a top surface (not labeled) of the mold base  4  with the sidewalls  13  thereof located at two opposite sides of the core member  5  of the mold. A height of the sidewalls  13  is greater than the height of the lower portion  53  of the core member  5 . The through hole  12  is co-axially aligned with the tapped blind hole  52  of the core member  5 . 
     The bolt  2  includes a threaded rod  21  with outer thread  23  formed on an outer surface thereof, and a head  22  formed on a top end of the threaded rod  21 . The head  22  has a diameter lager than that of the threaded rod  21 . The washer  3  is ring-shaped with a central hole (not labeled) defined therein. The washer  3  is arranged on the substrate  11  of the supporting member  1  and surrounds the threaded rod  21  of the bolt  2 . An inner diameter of the washer  3  is greater than a diameter of the threaded rod  21  of the bolt  2  and less than a diameter of the head  22  of the bolt  2 . An outer diameter of the washer  3  is greater than the diameter of the head  22  of the bolt  2 . The threaded rod  21  has a height greater than a sum of a height of the washer  3  and the height of sidewalls  13  of the supporting member  1 , and less than a sum of a depth of the tapped blind hole  52 , the height of the sidewalls  13  and the height of the washer  3 . A height of the outer thread  23  of the threaded rod  21  of the bolt  2  is not less than the depth of the tapped blind hole  52  of the core member  5 . In this embodiment, the height of the outer thread  23  is greater than the depth of the tapped blind hole  52 . 
     Referring to  FIG. 2 , when the core member  5  of the mold needs to be replaced, the mold releasing device is mounted on the mold for releasing the core member  5  of the mold. The threaded rod  21  of the bolt  2  extends through the washer  3  and the through hole  12  of the substrate  11  of the supporting member  1  to the core member  5 . Since the height of the bolt  2  is greater than the sum of the supporting member  1  and the washer  3 , the bottom end of the bolt  2  extends into the tapped blind hole  54  of the core member  5 . The threaded rod  21  of the bolt  2  and the core member  5  cooperatively form a helical pair. Then rotates the head  22  of the bolts  2 , the threaded rod  21  of the bolt  2  rotates and moves downwardly along an axial direction thereof and threadedly engages into the tapped blind hole  52  of the core member  5 . When the head  22  of the bolt  2  contacts to the washer  3 , the bolt  2  cannot move downwardly. A bottom end of the threaded rod  21  of the bolt  22  is received in a top end of the tapped blind hole  54  of the core member  5 . A distance between the bottom end of the threaded rod  21  and a bottom end of the tapped blind hole  54  is a little greater than the height of the lower portion  53  of the core member  5 . 
     Referring to  FIG. 3 , then rotates the bolt  2  continually, the rotation of the bolt  2  turns to an axial movement of the core member through the action between the outer thread  23  of the threaded rod  21  and the inner thread  54  of the tapped blind hole  52 . For the distance between the threaded rod  21  and the tapped blind hole  54  is a little greater than the height of the lower portion  53 , the lower portion of the core member  5  can move upwardly and axially to a position a little higher than the step of the mold base  4 . For the height of the sidewalls  13  of the supporting member  1  is higher than that of the lower portion  53  of the core member  5 , when the lower portion  53  of the core member is a little higher than the step of the mold base  4 , the upper portion  51  of the core member is lower than the substrate  11  of the supporting member  1 . The core member  5  thus is conveniently and accurately released from the mold base  4  as the rotation of the bolt  2 . The washer  3  arranged between the supporting member  1  and the bolt  2  prevents friction occurring between the head  22  and the substrate  11  during rotation of the bolt  2 . Alternatively, the washer  3  can be omitted, and the head  22  of the bolt  2  abuts against the substrate  11  of the supporting member  1 . In this situation, rotation of the bolt  2  can be turned to the axial movement of the core member  5  through the action of the outer thread  23  of the bolt  2  and the inner thread  54  of the core member  5 . 
     As stated above, the mold releasing device and the mold releasing method employ a bolt  2  threadedly engaging into the core member  5  to form a helical pair, therefore, during mold releasing processes, the core member  5  moves axially and outwardly during rotation of the bolt  2 . The movement of the core member  5  is accurate and thus problems such as abrasion generated by pulling the core member  5  can be avoided. A service life of the mold is elongated and a quality of the workpiece formed using such a mold is improved. Alternatively, the supporting member  1  can define a thread in the through hole  12  thereof, and the bolt  2  can be threadedly engaged with the thread of the supporting member  1  and preassembled to the supporting member  1 . As a result, transportation or mounting of the mold releasing device is convenient. 
     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): 8