Patent Publication Number: US-2012027881-A1

Title: Mold

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a mold, and in particular to a mold combined with a machine control unit. 
     2. The Related Arts 
     Modern industries use molds to perform mass production. A mold generally comprises an ejection mechanism for ejecting a molded product and a machine control unit that detects if the ejection mechanism is properly returned after the ejection of a molded product. The machine control unit transmits a signal indicating the return of the ejection mechanism to the molding machine and the molding machine issues a control instruction for starting the next operation. Reference is now made to  FIG. 1  of the attached drawings, which shows a conventional mold  100 ′. The mold  100 ′ comprises upper and lower mold members  10 ′ and a contact type machine control unit  20 ′. The contact type machine control unit  20 ′ comprises a body  21 ′, which has a top face carrying thereon a spring plate  22 ′ and a projection  23 ′ that is arranged below and spaced from the spring plate  22 ′ by a predetermined distance. The lower mold member  10 ′ comprises an ejection mechanism  11 ′, and the ejection mechanism  11 ′ comprises a depression block  111 ′ that is positioned against the spring plate  22 ′ and a plurality of ejection pins  112 ′. After a molded product is cooled down in the mold and properly shaped, the mold  100 ′ is opened, and the ejection mechanism  11 ′ operates to eject the molded product out of the mold. The ejection mechanism is then acted upon by the spring force of the springs  30 ′ for returning to the original position, where the depression block  111 ′ depresses down the spring plate  22 ′ to make the spring plate  22 ′ engaging the projection  23 ′. The body  21 ′therefore issues a signal indicating the returning of the ejection mechanism  11 ′ to the molding machine through a signal transmission cable. As a result of such a signal, the molding machine issues an operation instruction of closing the mold for next cycle of molding operation. 
     However, the known contact type machine control unit  20 ′ is disadvantageous in that the spring plate  22 ′ is susceptible to permanent deformation and loss of spring force after repeated operations so that the spring plate  22 ′ gets in contact with the projection  23 ′ before the ejection mechanism  11 ′ is properly returned to the original position. In other words, a molded product may get ejected when the mold  100 ′ has not yet been completely opened, or the mold is closed before the ejection mechanism  11 ′ is not properly returned. This eventually causes undesired damage to the mold  100 ′. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to overcome the problem discussed above by providing a mold that comprises a machine control unit for timely and correctly detect the status of an ejection mechanism. 
     To achieve the above objective, the present invention provides a mold, which comprises an upper mold member, a lower mold member, and a machine control unit. The lower mold member comprises a support board, a molding mechanism mounted on the support board, and an ejection mechanism. The support board has a front side forming a receiving compartment. The molding mechanism comprises a mold cavity. The machine control unit is mounted in the receiving compartment of the support board and comprises an optic sensor. 
     As described above, the mold of the present invention comprises a machine control unit that comprises an optic sensor to detect the returned and non-returned statuses of the ejection mechanism and transmit the result of detection to the molding machine of the mold, whereby the molding machine can be timely and correctly informed of the status of the ejection mechanism for correctly issuing a subsequent operation instruction. In this way, the potential risk that the mold is damaged by improper operation of the molding machine can be eliminated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be apparent to those skilled in the art by reading the following description of preferred embodiments of the present invention and the best modes for carrying out the present invention, with reference to the attached drawings, in which: 
         FIG. 1  is a front view of a conventional mold, in which an upper mold member and a lower mold member are shown in sections; and 
         FIG. 2  is a front view of a mold according to the present invention, in which an upper mold member and a lower mold member are shown in sections. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     With reference to the drawings and in particular  FIG. 2 , the present invention provides a mold, which is generally designated at  100 . The mold  100  comprises an upper mold member  10 , a lower mold member  20 , and a machine control unit  30  mounted on the lower mold member  20 . 
     The lower mold member  20  comprises a support board  21 , a molding mechanism mounted on the support board  21 , and an ejection mechanism  23 . In the embodiment illustrated, the support board  21  is in the form of a flat plate, but it can be of any other desired shape and configuration. The support board  21  comprises an upright sliding rod (not shown) mounted thereon. The support board  21  has a front side, which forms a receiving compartment  211  extending vertically through the support board  21  and a cable channel  212  in communication with the receiving compartment  211 . The molding mechanism comprises two side boards  221  that mounted on a top surface of the support board  21  in a vertically erected manner and a lower mold board  222  mounted atop the two side boards  221 . The lower mold board  222  forms a mold cavity  223 . 
     The ejection mechanism  23  is arranged between the two side boards  221 . In the embodiment illustrated, the ejection mechanism  23  comprises an ejection plate  231 , springs  232 , and a plurality of ejection pins  233  vertically erected and mounted on the ejection plate  231 . The ejection plate  231  has a lower portion forming a receiving slot  2311 . The ejection plate  231  is slidably fit over the sliding rod of the support board  21  for vertically sliding along the sliding rod. The ejection pins  233  move up and down with the ejection plate  231  and extend upward through the lower mold board  222  to project into the mold cavity  223 . 
     The machine control unit  30  is received and fixed in the receiving compartment  211  of the support board  21  and comprises a mounting plate  31 , an optic sensor  32 , and a transmission cable  33 . 
     The optic sensor  32  is fixed to the support board  21  by the mounting plate  31 . The optic sensor  32  has an upper portion that is received in the receiving slot  2311  of the ejection plate  231 . The optic sensor  32  comprises a transmitter and a receiver (not shown). The optic sensor  32  has a lower end electrically connected to a signal transmission cable  33 , which is set in the cable channel  212  of the support board  21 . 
     When the mold  100  according to the present invention  100  is completely opened, the ejection mechanism  23  is caused to move upward from a home position and thus drives the ejection pins  233  upwards to eject a molded product out of the mold. Then, the ejection mechanism  23 , under the action of the spring force of the springs  232 , returns to its home position. During this process, the transmitter of the optic sensor  32  continuously emits and transmits a light beam, such as an infrared beam, and the receiver is set in a standby condition for receiving the light beam. Once the optic sensor  32  of the support board  21  detects an upper portion of the ejection plate  231  of the ejection mechanism  23  is approaching to a predetermined distance, meaning the upper portion of the ejection plate  231  effectively reflecting the light beam from the transmitter of the optic sensor  32  back to the receiver, the optic sensor  32  issues a signal indicating the returning of the ejection mechanism  23  and transmits the signal through the transmission cable  33  to the molding machine so that the molding machine may correctly issue a subsequent operation instruction, such as closing the mold. 
     In summary, the mold  100  according to the present invention  100  comprises a machine control unit  30  that comprises an optic sensor  32  to detect the ejection mechanism  23  reaching a predetermined location, for correctly determining that the ejection mechanism  23  is properly returned to the home position, and transmit the result of detection to the molding machine so that the molding machine can be timely and correctly informed of the status of the ejection mechanism for correctly issuing a subsequent operation instruction. In this way, the potential risk that the mold is damaged by improper operation of the molding machine can be eliminated. 
     Although the present invention has been described with reference to the preferred embodiment thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.