Abstract:
A sequential mold lifter for a molded part forming device comprises at least first, second and third lifter segments that slidably engage one another. The first and third lifter sections are positioned on opposite sides of the second section and slide upwardly and inwardly on inclined lifter surfaces on the second lifter section. Separate actuators extend all of the lifter sections to a first extended position and then extend the first and third actuators upwardly and inwardly beyond the second actuator to a second extended position. The relative movement of the lifter sections dislodges the molded product from the mold and then dislodges the product from the lifter. The inclination of the actuators can vary with the positions of the lifter sections. Movable slides support the actuators but permit variation in the inclination of the actuators.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
       [0001]    This application is based on and claims the benefit of the filing date of co-pending U.S. Provisional Patent Application Serial No. 60/237,609, entitled Sequential Mold Lifter and filed on Oct. 3, 2000, by Timothy A. Mowery and Mark S. Clark, the disclosure of which is incorporated here by reference. 
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not Applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    The invention relates to molded part forming devices and in particular to a mold that has two portions that align with and abut one another in a closed position, defining a mold cavity between the two portions in the closed position, and the two portions being separated from one another in an open position. The mold further having a lifter that seats into the mold cavity and abuts at least one of the two mold portions in the closed position.  
         BRIEF SUMMARY OF THE INVENTION  
         [0004]    In accordance with the present invention, a sequential mold lifter for a molded part forming device, such as an injection molding machine, which has cooperating first and second mold portions that open and close, comprises a multipart lifter that moves in such a way that a molded part that envelops the lifter is automatically removed from the mold and the mold lifter. The sequential mold lifter comprises at least first and second lifter segments and preferably at a third lifter section as well. The lifter segments slidably engage one another. In one aspect of the invention, the first and third lifter sections are positioned on opposite sides of the second section and slide upwardly and inwardly on inclined lifter surfaces on the second lifter section. A first actuator extends and retracts the first lifter segment relative to one of the first and the second mold portions. A second actuator extends and retracts the second lifter segment relative to the same one of the first and the second mold portions. A third actuator extends and retracts the third lifter. Preferably the first and third actuators are inclined at substantially the same angle as the lifter surfaces between the lifter sections. The actuators extend all of the lifter sections simultaneously to a first extended position and further extend the first and third actuators beyond the second actuator to a second extended position. The relative movement of the lifter sections dislodges the molded product from the mold and then dislodges the product from the lifter. The inclination of the actuators can vary with the positions of the lifter sections. Movable slides support the actuators but permit variation in the inclination of the actuators.  
           [0005]    These and other feature, objects, and benefits of the invention will be recognized by one having ordinary skill in the art and by those who practice the invention, from the specification, the claims, and the drawing figures. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0006]    [0006]FIG. 1 is a fragmentary longitudinal cross-sectional view of a mold that incorporates a sequential mold lifter of the invention, showing the mold and the sequential mold lifter in a closed condition;  
         [0007]    [0007]FIG. 2 is the view of FIG. 1, showing a top of the mold removed and the sequential mold lifter in a partially lifted position;  
         [0008]    [0008]FIG. 3 is the view of FIG. 2, showing the sequential mold lifter in a fully lifted position;  
         [0009]    [0009]FIG. 4 is a fragmentary transverse cross-sectional view along line IV-IV of FIG. 1; and  
         [0010]    [0010]FIG. 5 is a fragmentary plan view of an interface between two segments of the sequential mold lifter as indicated by sight line V-V of FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]    A preferred embodiment of a sequential mold lifter according to the invention is generally shown in the drawing figures. As shown, the sequential mold lifter is useful in a molded part forming device that has a first mold portion  10  and a cooperating second mold portion  12  (FIG. 1). As will be understood by one having ordinary skill in the art, a device that forms molded parts commonly includes the first and the second mold portions  10  and  12 , respectively, which align with and abut one another in a closed position and define a mold cavity  14  in which a molded part  16  maybe formed. Further, the first and the second mold portions  10  and  12 , respectively, separate from one another in an open position (FIGS. 2 and 3) as will be understood by one having ordinary skill in the art.  
         [0012]    The sequential mold lifter as shown includes a lifter  30  that is sectioned into first, second and third lifter sections  32 ,  34 , and  36 , respectively. Each of the three lifter sections  32 ,  34 , and  36 , respectively, is connected with the second mold portion  12  by an actuator  42 ,  44 , and  46 , respectively. A drive mechanism  47  (shown schematically) controls the actuation of the actuators. This can be conventional.  
         [0013]    Each of the three lifter sections  32 ,  34 , and  36 , respectively, may be constructed of any suitable structural material as will be understood by one having ordinary skill in the art. The first lifter section  32  has a generally planar first lifter surface  52 , while the second lifter section  34  has opposing generally planar second and third lifter surfaces  54  and  56 , respectively, and the third lifter section  36  has a generally planar fourth lifter surface  58  (FIG. 3). The first lifter section  32  and the second lifter section  34  are oriented relative to one another with the first lifter surface  52  and the second lifter surface  54  in abutting engagement. Likewise, the second lifter section  34  and the third lifter section  36  are oriented relative to one another with the third lifter surface  56  and the fourth lifter surface  58  in abutting engagement.  
         [0014]    A connector  62  slidably interconnects the first and the second lifter segments  32  and  34 , respectively, and maintains the relative positioning of the first and the second lifter segments and the first and second lifter surface  52  and  54 , respectively. While various connectors may be used, the inventors have found that a dovetail joint between the first and the second lifter segments  32  and  34 , respectively, is effective without being unduly complicated. Likewise, a connector  64  slidably interconnects the second and the third lifter segments  34  and  36 , respectively, and maintains the relative positioning of the second and the third lifter segments and the third and fourth lifter surface  56  and  58 , respectively.  
         [0015]    Each of the actuators,  42 ,  44 , and  46 , respectively, may be any of various actuators that are or may be known to one having ordinary skill in the art. The actuator  42  has a line or axis of action  72 , while the actuator  44  has a line or axis of action  74  and the actuator  46  has a line or axis of action  76 .  
         [0016]    The second actuator  44  connects between the second lifter section  34  and a second cavity segment  84 . The second actuator  44  slides between a retracted position (FIG. 1) and a first extended position (FIG. 2). The second lifter section  34  seats into the mold cavity and abuts at least some of the second cavity segment  84  in the retracted position. Further, the second lifter section  34  is at least partially spaced apart from the second cavity segment  84  in the first extended position.  
         [0017]    The first actuator  42  connects between the first lifter section  32  and a first cavity segment  82  while the third actuator  46  connects between the third lifter section  36  and a third cavity segment  86 . As with the second actuator  44  and the second lifter section  34 , just discussed above, the first and third actuators  42  and  46 , respectively, also slide between the retracted position (FIG. 1) and the first extended position (FIG. 2). The first lifter section  32  seats into the mold cavity and abuts at least some of the first cavity segment  82  in the retracted position while the third lifter section  36  seats into the mold cavity and abuts at least some of the third cavity segment  86  in the retracted position. Further, the first lifter section  32  is at least partially spaced apart from the first cavity segment  82  in the first extended position while the third lifter section  36  is at least partially spaced apart from the third cavity segment  86  in the first extended position.  
         [0018]    Unlike the second actuator  44  and the second lifter section  34 , however, the first and third actuators  42  and  46 , respectively, further extend through the first extended position to a second extended position (FIG. 3) in which the first and third lifter sections  32  and  36 , respectively, are further spaced apart from the first and third cavity segments  82  and  86 , respectively. This then means that the first and third lifter sections  32  and  36  are also extended beyond the second lifter section  34 .  
         [0019]    Moving the lifter  30 , which has the lifter sections  32 ,  34 , and  36 , for the retracted position in the second mold portion  12  (FIG. 1) to the first extended position (FIG. 2) facilitates removal of the molded part  16 , especially in the case of when at least a portion of the molded part wraps around the lifter. Now, the further extension of the first and third lifter sections,  32  and  36 , respectively, past the second lifter section  34  to the second extended position (FIG. 3) actually removes the molded part  16  from the second lifter section  34 . It should be noted that the molded part  16  is a flexible resilient member that can deform around the lifter  30  and its sections  32 ,  34 , and  36  and recover its original molded configuration without damage.  
         [0020]    To minimize potential damage to the molded part  16 , however, when the first and third lifter sections,  32  and  36 , respectively, move to the second extended position (FIG. 3), the first and third lifter sections most preferably also move toward each other when further extending from the first extended position to the second extended position. This may be accomplished in the preferred embodiment by defining a first reference plane that coincides with an interface between the first lifter surface  52  and the second lifter surface  54  and further orienting the first reference plane parallel with the axis  72 . The axis  72  is in the illustrated embodiment preferably inclined at an included angle of about 15 degrees relative to the axis  74 . Likewise, a second reference plane that coincides with an interface between the third lifter surface  56  and the fourth lifter surface  58  is oriented parallel with the axis  76 . The axis  76  is preferably similarly inclined at an included angle of about 15 degrees relative to the axis  74 , which of course defines an angle of about 30 degrees between the axis  72  and the axis  76 .  
         [0021]    With the first and the second reference planes so defined, the first lifter section  32  and the third lifter section  36  will cam or slide along the second lifter second  34 , closing toward one another, as the first lifter section and the third lifter section progress from the first extended position (FIG. 2) to the second extended position (FIG. 3). In the second extended position, the first lifter section  32  and the third lifter section  36  will be closer to one another than in either of the retracted position (FIG. 1) or the first extended position (FIG. 2). Thus, the molded part  16  will inherently peel or separate from the first lifter section  32  and the third lifter section  36  as the first lifter section and the third lifter section move toward one another and to the second extended position.  
         [0022]    Because the first and the third lifter sections  32  and  36 , respectively, cam or slide along the second lifter second  34 , closing toward one another, as the first and the third lifter sections progress from the first extended position to the second extended position, each of the first and the third actuators  42  and  46 , respectively, must be provided a tolerance of movement with the first and the third lifter sections. Conversely, the first and the third lifter sections  32  and  36 , respectively, cam along the second lifter second  34 , separating from one another, as the first and the third lifter sections progress from the second extended position and through the first extended position to the retracted position. Thus, each of the first actuator  42  and the third actuator  46  is movably mounted in the second or lower mold portion  12 . This can be accomplished by pivot joints  43  and  45  at inner or lower ends of the actuators.  
         [0023]    More particularly, movement of the first and the third actuators  42  and  46 , respectively, is accommodated with associated slides and passages. The first actuator  42  extends from the first lifter section  32  and through an actuator passage  92  to a slide  94 . Likewise, the third actuator  46  extends from the third lifter section  36  and through an actuator passage  96  to a slide  98 . Each of the actuator passage  92  and the actuator passage  96  is a generally cylindrical passage that has an elongated or oval cross section. Thus, movement of the first and the third actuators  42  and  46 , respectively, toward and away from one another when they extend and retract is provided, as will be understood by one having ordinary skill in the art.  
         [0024]    It will further be understood by one having ordinary skill in the art and by those who practice the invention, that various modifications and improvements may be made without departing from the spirit of the disclosed concept. Various relational terms, including left, right, front, back, top, and bottom, for example, are used in the detailed description of the invention and in the claims only to convey relative positioning of various elements of the claimed invention. The scope of protection afforded is to be determined by the claims and by the breadth of interpretation allowed by law.