Abstract:
A method for core pulling and insertion in synchronization with the opening and closing of the mold in a cavity including a fixing half and a moving half, or a fixing half, a moving half and several cavity plates installed between fixing half and moving half as well as the core moving reciprocally inside the cavity, wherein a downward movement of a transmission gear is coupled with an opening of the mold, synchronous with a pulling of the core out of the cavity, and an upward movement of the transmission gear is coupled with a closing of the mold, synchronous with an insertion of the core into the cavity.

Description:
BACKGROUND OF THE INVENTION 
     (a) Field of the Invention 
     The invention is related to machines in injection molding and die casting, and is especially related to a method for core pulling and insertion in synchronization with the opening and closing of the mold as well as the apparatus to realize the said method in the molding process. 
     (b) Description of the Prior Art 
     The core pulling and insertion method and device used in the injection molding and die casting production process have been through changes. The conventional core pulling and insertion method for injection molding adopts a leaning guide post core pulling and insertion method, whereof as the leaning guide post has a longer translation distance in working but has a shorter stroke in actual core pulling and insertion due to its inherited structure, lowering work effectiveness and increasing cost. Hence, based on this, a method such as the mold external hydraulic/pneumatic cylinder actuated core pulling and insertion is employed as an improvement, similar to this technology includes the publicized application of the Chinese patent no. 200510049399.3′ A demolding device for the mold with a side core extraction and extrusion mechanism which discloses that the top of the fixing plate at one side of the mold is installed with a hydraulic cylinder which is through the work table of the press or injection molding machine to allow the piston rod of the said hydraulic cylinder to connect with the mold push rod, so that the said push rod is independently controlled by the installed hydraulic cylinder instead of interlinking with the work table of the press; thereby it effectively resolves the shortened stroke of molding core pulling and insertion problem and also has a higher work effectiveness compared with the afore mentioned technology. Nonetheless, both of the said methods have a the same imperfection, i.e. the opening and closing of the mold as well as the core pulling and insertion are separate actions which can only be operated manually, and due to inadequacy of automation, mis-operation may occur easily to damage the molds. Therefore, they shall be replaced, and a method and device for the molding core pulling and insertion with a higher degree of automation is urgently needed to be researched and developed for the replacement. The above said two methods of existing arts have another imperfection of unable to randomly set the stroke of core pulling and insertion according to requirement of workpiece that needs to be further improved. 
     SUMMARY OF THE INVENTIONS 
     The purpose of the invention is to disclose a method and device, in which the core pulling and insertion with random strokes setting is synchronized with the opening and closing of the mold, i.e. a method and device for core pulling and insertion in synchronization with the opening and closing of the mold. 
     The technical method for the invention is realized as follows: 
     A method for core pulling and insertion in synchronization with the opening and closing of the mold which is used in a cavity constituted by a fixing half and a moving half, or a cavity constituted by a fixing half, a moving half and several cavity plates installed between fixing half and moving half as well as the cores moving reciprocally inside the cavity, wherein it is characterized to be completed by the following steps: 
     (1) In mold opening, the core lock piece opening stroke is preset. 
     (2) In mold opening, moving half driving the core lock piece travels the stroke said in step (1) to open until reaching either limit of gear rack or gear chain, whereby the hook reaches the position to start core pulling. 
     (3) The moving half continue to travel until mold opening completed, the mold push rod is acted to complete demolding. 
     (4) In mold closing, moving half driving hook travels reversely to drive core to insert until reaching either limit of gear rack or gear chain and unlocking hook lock. The moving half driving the core lock piece travels the stroke said in (1) and then locks the core to prepare for mold opening after casting. 
     (5) Repeat the steps (1) to (4). 
     The above said method for core pulling and insertion in synchronization with the opening and closing of the mold is characterized in that the gear chain used in step (4) is a linear chain. 
     The above said method for core pulling and insertion in synchronization with the opening and closing of the mold is characterized in that in the process of steps (2) to (4), the stroke of core pulling and insertion is adjusted by number of teeth of the gear engaged with the gear train. 
     The above method for core pulling and insertion in synchronization with the opening and closing of the mold is characterized in that in the process of steps (2) to (4), the angle between the core and the cavity can be arbitrarily set to any angle according to workpiece requirement. 
     To realize the said method, the following is disclosed: 
     A device for core pulling and insertion in synchronization with the opening and closing of the mold is comprised of a cavity constituted by a fixing half and a moving half, or a cavity constituted by a fixing half, a moving half and several cavity plates installed between fixing half and moving half as well as the cores moving reciprocally inside the cavity, wherein it is characterized in that: one side of the moving half is installed with the guide press piece to match with the core, the gear spindles are firmly installed between the two guide press pieces, the pulling and insertion gear installed on the spindle is engaged with the transmission rack which is affixed with the core. The transmission gear installed on the spindle is engaged with the gear rack or gear chain installed outside the mold, and the hook installed on above the gear rack or gear train is engaged with the hook lock. 
     The said fixing half is affixed with the core lock piece to fit with the concaved slot of core. 
     The chute is installed on the said core to fit with guide rail of the guide press piece. 
     The lock head of said hook lock is connected with a spring which is affixed to the exterior of the mold. 
     The invention discloses to utilize the mechanical opening and closing of the mold in injection molding machines and presses to synchronously complete the demolding core pulling and core insertion work for the products, thereby the clogging problems in the 45-degree angle core pulling and insertion hydraulic cylinder, injection molding machines and the four guiding cylinders of the press as well as the safety door closing and clogging problems in injection molding machines and presses due to long hydraulic cylinder can be solved by the said invention to provide for continuous production and process control. It has a simple structure with compact, precise and reliable in stable operation characteristics, whereby to provide an automatic equipment for safety production and environmental protection. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial 3D structural diagram of the invented device 
         FIG. 2  is a partial 3D structural diagram of the invented device after removing the fixing half. 
         FIG. 3  is a plane layout of the gear train portion of the invented device. 
         FIG. 4  is a plane layout of the rack gear portion of the invented device. 
         FIG. 5  is a partial 3D structural diagram of another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The embodiment of the invention is described in the following along with the attached drawings: 
     Please refer to  FIGS. 1 to 4 , a core pulling and inserting device in synchronization with the opening and closing of the mold is comprised of a cavity constituted by a fixing half  1  and a moving half  2 , or a cavity constituted by a fixing half  1 , a moving half  2  and several cavity plates installed between fixing half  1  and moving half  2  as well as the core  3  which are moving reciprocally inside the cavity, whereof one side of the moving half  2  is installed with a guide press piece  4  to match with the core  3 , the gear spindles  5  are firmly installed between the two guide press pieces  4 , the core pulling and insertion gear  6  installed on the spindle  5  is engaged with the transmission rack  7  which is affixed with the core  3 , or the core pulling and insertion gear  6  can also be designed to engage with core  3  directly. The transmission gear  8  installed on the spindle  5  is engaged with the gear rack  9  or gear chain  10  installed outside the mold, and the hook  11  installed on above the gear rack  9  or gear train  10  is engaged with the hook lock  12 . Thereof, the gear chain arrangement allow the core  3  to be pulled out when the moving half  2  is opened and allow the core  3  to be inserted when the mold is closed. As shown in  FIG. 1 , the gear train is constituted by the four gears inter-connected through the spindles  5  within the open space between the two guide press pieces  4 , one of the gears is engaged with the transmission gear to form a synchronization, i.e. when the transmission gear  8  is moved downwards, the four gears then drive the core  3  which is connected with spindles  5  to pull outwards, when the mold is closing, the transmission gear  8  is moved upwards, the four gears then drive the core  3  to insert inwards. 
     Please refer to  FIG. 5 , whereof the gear trains in  FIG. 1  can be replaced by a bearing  16  installed on the guide press piece  4  to allow the spindle  5  to be connected with the bearing  16 , while the outer ring of the bearing  16  is firmly fixed inside the guide press piece  4 . 
     Through the above installed core pulling and inserting device in synchronization with the opening and closing of the mold, the fixing half  1  is affixed with the core lock piece  13  to fit with the concaved slot of core  3  to ensure fixation of the core for casting products. In mold closing, the core lock piece  13  is inserted into the concaved slot for locking; and in mold opening, the core lock piece  13  is pulled out of the concaved slot for unlocking. 
     Through the above installed core pulling and inserting device in synchronization with the opening and closing of the mold, the chute  31  is installed on the said core  3  to fit with guide rail  41  of the guide press piece  4 , thereby to allow the core  3  to translate reciprocally on the guide press piece  4 . 
     Through the above installed core pulling and inserting device in synchronization with the opening and closing of the mold, the lock head  121  of said hook lock  12  is connected with a spring  14  which is affixed to the exterior of the mold. The function of spring  14  is to un-constrain hook  11  from constraint piece  15  when the mold closing reach to limits of either the gear rack  9  or gear chain  10 . 
     A method to produce products by the said device is disclosed: 
     (1) In mold opening, the core lock piece  13  opening stroke is preset: i.e. the distance after unlocking hook  11  from the hook lock  12 . 
     (2) In mold opening, moving half  2  driving the core lock piece  13  travels the stoke said in step (1) to open until reaching either limit of gear rack  9  or gear chain  10 , whereby the hook  11  reaches the position to start core  3  pulling. 
     (3) The moving half continue to travel until mold opening completed, the mold push rod is acted to complete demolding. 
     (4) In mold closing, moving half  2  driving hook  11  travels reversely to drive core  3  to insert until reaching either limit of gear rack  9  or gear chain  10  and unlocking hook lock  12 . The moving half  2  driving the core lock piece  13  travels the stroke said in (1) and then locks the core  3  to prepare for mold opening after casting. 
     (5) Repeat steps (1)-(4). 
     The gear chain  10  used in the method is in linear shape, and it also can be directly replaced by the gear rack  9 . The gear rack  9  can be used for short core pulling and insertion stroke and gear chain  10  can be used for long core pulling and insertion stroke, thereby the said device has a wider range of application. 
     As shown in  FIG. 3 , the gear chain  10  is used for long core pulling and insertion stroke, partial chain of gear chain  10  is placed between the mold push rod and base plate of the moving half  2 . 
     One part of the method is that the core pulling and insertion stroke is adjusted through the gear engaged with the gear chain  10 , such as by adjusting number of teeth of the core pulling and insertion gear  6  or of the transmission gear  8 . 
     One part of the method is that the angle between the core  3  and the cavity can be arbitrarily set to any angle according to workpiece requirement in order to satisfy the requirements of core pulling and insertion in abnormal conditions. 
       FIG. 5  shows another embodiment of the invention: 
     A device for core pulling and insertion in synchronization with the opening and closing of the mold is mainly used to produce piping covers, in which as compared with the aforesaid embodiments of the invention, only one spindle  5  is needed to install, the gear inside the guide press piece  4  of the gear chain is replaced by the bearing  16  installed on the pad of moving half  2 , the transmission gear  8  on the spindle  5  is engaged with the gear chain  9 , the core pulling and insertion gear  6  is not engaged with the round gear shown in  FIG. 1  but changed to engage with the cone gear instead, so that the linear core pulling and insertion movement is changed to be driven by the helical screw movement. 
     A piping cover manufacturing method by the device shown in  FIG. 5  is described below: 
     (1) In mold opening, the stroke after unlocking the hook  11  from the hook lock  12  is preset: i.e. setting required pipe cover demolding distance. The linear length setting to position core  3  by the core lock piece  13  is changed to axial positioning by helical screw which is a common method used in the same field. 
     (2) In mold opening, moving half  2  driving the core lock piece  13  travels the stoke said in step (1) to open until reaching either limit of gear rack  9  or gear chain  10 , whereby the hook  11  reaches the position to start core  3  pulling. 
     (3) The moving half continue to travel until mold opening completed, the demolding is completed and the piping cover is screwed out. Similarly, after the linear length setting to position core  3  by core lock piece  13  is changed to axial positioning by helical screw, the said mold push rod demolding is replaced by the helical screw demolding. 
     (4) In mold closing, moving half  2  driving hook  11  travels reversely to drive piping cover type core to insert until reaching either limit of gear rack  9  or gear chain  10  and unlocking hook lock  12 . The moving half  2  travels the stroke said in (1) and then locks the core to prepare for mold opening after casting. 
     (5) Repeat steps (1) to (4). 
     The invention can applied in a wide field, the transfer piping manufacture is related to applications in every field. The size of the mold and die device can be correspondingly designed according to the required specifications of the products. Especially, the methods of the invention such as the core pulling and inserting in synchronization with the opening and closing of the mold of the invention, gear driven core pulling and insertion, and core pulling and insertion stroke presetting in the mold opening and closing process are all essences of the invention, they are all belong to the protected range of the invention. 
     All components of the said device are made of metal material