Abstract:
A mold structure ( 100 ) includes a mold plate ( 402 ) and a fiber-optic sensor ( 30 ) mounted therein. The fiber-optic sensor may detect whether a metal insert has been put into the mold plate before the mold structure is closed. If the metal insert is already put in a desired position, the mold structure can be closed so as to avoid leaving out the metal insert. Therefore, the production and efficiency are greatly increased.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to mold structures and, particularly, to a mold structure with a fiber-optic sensor used in insert molding. 
         [0003]    2. Description of related art 
         [0004]    Insert molding is a process in which plastic is injected into a mold that contains an insert. The result of insert molding is a single molded plastic piece with an insert surrounded by the plastic. Inserts can be made of metal or different types of plastic. Insert molding is used in many industries. Applications for insert molding include the production of insert-molded couplings, threaded fasteners, filters, and electrical components. Insert molding expands the capabilities of plastic and can help reduce the cost of products by limiting the amount of costly metals needed to manufacture such products. 
         [0005]    During a typical insert molding process, first a metal insert is put into a mold cavity of a mold. Then, the mold is closed so that molten material can be injected into the mold cavity, via a runner. The molten material in the cavity is cooled to form the molded product. However, if the metal insert is not put into the mold yet the mold is still closed, the mold could rather easily be destroyed. This situation not only affects manufacturing speed but also greatly reduces the work efficiency. 
         [0006]    Therefore, a mold structure that can help prevent injection of molten material when no insert is present is desired in order to overcome the above-described shortcomings. 
       SUMMARY OF THE INVENTION 
       [0007]    One embodiment of a mold structure includes a mold plate and a fiber-optic sensor mounted therein. The fiber-optic sensor is configured (i.e., structured and arranged) for detecting whether a metal insert is put/placed into the mold plate before the mold structure is closed. If the metal insert is already placed in a desired position, the mold structure is permitted to close, so as to avoid leaving out the metal insert. Therefore, the production and efficiency are greatly increased. 
         [0008]    Other advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Many aspects of the present mold structure with a fiber-optic sensor can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present mold structure with a fiber-optic sensor. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0010]      FIG. 1  is an exploded, isometric view of a present mold structure, according to one embodiment; 
           [0011]      FIG. 2  is a schematic view of a fiber-optic sensor of  FIG. 1 ; 
           [0012]      FIG. 3  is an assembled view of the mold structure of  FIG. 1 ; and 
           [0013]      FIG. 4  is a cross-sectional view of the mold structure of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0014]    Referring now to the drawings in detail,  FIG. 1  shows a mold structure  100 , in accordance with a present embodiment. The mold structure  1   00  includes a movable mold plate  40  and a fiber-optic sensor  30 . The fiber-optic sensor  30  may be fixed in the movable mold plate  40 . A metal insert  50  is embedded in the mold structure  100 . 
         [0015]    The movable mold plate  40  includes a mold seat  402 , a mold core  404 , and a support element  406 . The mold seat  402  is substantially cube-shaped or at least rectangular parallelepiped in shape and defines a rectangular cavity  4022  in a central area thereof. A stepped hole  4024  is defined in a bottom surface of the cavity  4022  (i.e., extends directly from such bottom surface further into the mold seat  402 ). A sidewall of the mold seat  402  defines a side hole  4026  therein. The side hole  4026  is a through-hole that communicates with the stepped hole  4024 . The mold core  404  is usefully embedded in the mold cavity  4022  of the mold seat  402  and is beneficially fixed to the mold seat  402  by means of bolts. The mold core  404  defines a rectangular groove  4042  in a central area thereof. A bottom surface of the groove  4042  defines a core through hole  4044 . An axis of the core through hole  4044  is aligned with that of the stepped hole  4024 . The support element  406  is substantially rectangular and opportunely is embedded in the groove  4042 . The support element  406  is thereby configured for supporting the metal insert  50 . The support element  406  defines a central hole  4062  therein. An axis of the central hole  4062  is aligned with that of the core through hole  4044 . 
         [0016]    Referring to  FIG. 2 , the fiber-optic sensor  30  includes a fiber-optic head  302 , a fixing portion  304 , a sensor light conduit  306 , and a fiber-optic amplifier  308 . One end/face of the fixing portion  304  is connected to the fiber-optic head  302 , and the opposite end/face of the fixing portion  304  is optically connected to a front/first end of the sensor light conduit  306  (i.e., in the form of an output (i.e., light-transmitting) fiber optic and an input (i.e., light-receiving) fiber optic). An opposite end of the sensor light conduit  306  is divided into two branches and is optically connected to the fiber-optic amplifier  308 . The fiber-optic head  302  is cylindrical in shape and includes a light-emitting portion  3022  and a light-receiving portion  3024 . The fixing portion  304  is substantially cylindrical in shape (i.e., disk-shaped). A diameter of the fixing portion  304  is significantly larger than those of the fiber-optic head  302  and the sensor light conduit  306 . In particular, the diameter thereof is similar to that of the stepped hole  4024  of the movable mold plate  40 , to permit a slide-fit therebetween and to thereby ensure that the fixing portion  304  is held in place during the molding procedure. As such, the fixing portion  304  is indeed able to fix the fiber-optic head  302  relative to the movable mold plate  40 . 
         [0017]    The light from the fiber-optic amplifier  308  may be transmitted to the light-emitting portion  3022  of the fiber-optic head  302  through the sensor light conduit  306 . The sensor light conduit  306  is an optic channel (i.e., a fiber optic) configuring for transmitting light. The light-emitting portion  3022  is configured for transmitting/directing light onto the metal insert  50 . Meanwhile, the light-receiving portion  3022  is configured for receiving the reflected light from the metal insert  50 , and the reflected light is transmitted to the fiber-optic amplifier  308  though the sensor light conduit  306 . The fiber-optic amplifier  308  is configured for detecting/measuring the strength of the reflected light so as to judge whether the metal insert  50  has been placed in the mold  1   00 . It is to be understood that the junction between the sensor light conduit  306  and the fiber-optic head  302  at the fixing portion  304  could be either distinct or integral, for the purposes of the present mold sensor system. 
         [0018]    In assembly, referring to  FIGS. 3 and 4 , the fiber-optic sensor  30  is inserted into the stepped hole  4024  of the mold seat  402 . The fixing portion  304  slidingly fits into and resists a stepped surface of the stepped hole  4024 . The fiber-optic head  302  extends away from the mold cavity  4022  of the mold seat  402 . At the same time, the sensor light conduit  306  extends in the opposite direction away the fixing portion  304  than does the fiber-optic head  302 . The sensor light conduit  306  extends through the mold seat  402  and ultimately from the side hole  4026  thereof. The portion of the sensor light conduit  306  extending out of the side hole  4026  is connected to the fiber-optic amplifier  308 . The fiber-optic amplifier  308  is connected to a control circuit of a molding machine. 
         [0019]    In the opposite direction from the fixing portion  304 , the fiber-optic head  302  passes through the through hole  4044  of the mold core  404 , and the mold core  404  is fixed in the mold cavity  4022  of the mold seat  402  by means of, e.g., bolts. After that, the central hole  4062  of the support element  406  is placed around the fiber-optic head  302 , and the support element  406  is received in the groove  4042  of the mold core  404 . Finally, the metal insert  50  is fixed on the support element  406 . Note that a top/distal end of the fiber-optic head  302  needs to be lower than a top surface of the support element  50 , so as to avoid contact therebetween and thus avoid damage to that distal end. 
         [0020]    In use, the fiber-optic amplifier  308  produces light. The light is transmitted to the fiber-optic head  302  by the sensor light conduit  306 . Then, the light-emitting portion  3022  projects the light onto the metal insert  50 . The light is reflected by the metal insert  50  to the light-receiving portion  3024 . After that, the light-receiving portion  3024  again transmits light to the fiber-optic amplifier  308  through the sensor light conduit  306 . Owing to the closeness/proximity of the metal insert  50  and the fiber-optic head  302  of the fiber-optic amplifier  30  and, potentially in part, to the generally reflective nature of metals, the light reflected by the metal insert  50  is stronger than any light reflected by an opposed mold portion (not shown). Likewise, if measured prior to moving another opposing mold portion into place, little or no reflection would be detected if the metal insert  50  were not in place. Therefore, the fiber-optic amplifier  308  may detect stronger light signals. If the strength of the light signal is more than a critical value of the output circuit of the fiber-optic amplifier  308  (i.e., indicating that the metal insert  50  is in place), the amplifier may output signals to the control circuit of the mold machine so as to instruct the mold to close. If the metal insert  50  is not put/placed on the support element  406 , the fiber-optic head  302  will not receive enough reflected light and will not drive the mold machine to close. 
         [0021]    A main advantage of the mold structure is that the mold structure may judge whether the metal insert is put into the mold so as to instruct the mold machine to close or not, thus avoiding damage to the mold structure. Accordingly, the production and efficiency are greatly increased. Likewise, a reduction in long-term equipment expenditures (i.e., in terms of maintenance and/or replacement costs) can be expected. 
         [0022]    Understandably, the fiber sensor may be applied in other types of molds, such as pressing molds. The fiber-optic sensor also may be assembled into a fixed mold plate so as to detect the metal insert. 
         [0023]    In still further alternative embodiments, the number of the fiber-optic sensors may be two or more. Further, for example, if three or more fiber-optic sensors are employed, the fiber-optic sensors could be used not only to detect whether the metal insert is put into the mold but also may judge whether the metal insert is inserted flush to the sensor and/or the mold base. 
         [0024]    It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.