Abstract:
This invention discloses a mold assembly ( 6 ) and method for manufacturing a syringe container ( 5 ) which is provided with a cannula ( 51 ) and a syringe barrel ( 52 ). The mold assembly includes: a first set ( 61 ); a second set ( 65 ) movable to abut against the first set to define a mold cavity ( 621, 631, 661, 671 ); a core ( 69 ) in the mold cavity; a first clamping piece ( 64 ) secured to the first set; and a second clamping piece ( 68 ) secured to the second set; wherein the cannula is held by the clamping pieces. The method includes: placing one end of the cannula into a port ( 691 ) of the core; moving the sets such that the clamping pieces hold the cannula the moment the sets abut against each other; injecting polymeric material into the mold cavity; separate the sets; and removing the syringe container out of the core.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention generally relates to an injection molding method and mold assembly, and more particularly to a mold assembly and method for manufacturing a syringe container, more particular a polymeric syringe container. 
       BACKGROUND OF THE INVENTION 
       [0002]      FIG. 1  is an insert mold  1  for molding a needle  2  to an injection barrel  3  disclosed in U.S. publication patent No. 2010/0270702 A1, the disclosure of which is incorporated herein by reference. The conventional insert mold  1  is provided with an A-side mold  11 , a B-side mold  12 , a core member  13  and a collect mechanism  14 . 
         [0003]    For the conventional molding process, one end of a needle  1  is placed into a tip of the core member  13  firstly. Next, the A-side mold  11  is inserted over the core member  13  to an extent that the A-side mold  11  contacts the B-side mold  12 . Subsequently, the collect mechanism  14  is inserted in to a tapered receiving plenum  111  formed on left end of the A-side mold  11 . When flexible arms  141  of the collect mechanism  14  hold the needle  2 , molten polymeric material is injected into a mold space  112  defined between the A-side mold  11  and the B-side mold  12  through a gate  113  near broad end  114  of the mold space  112 . After the polymeric material in the mold space  112  is cooled, the collect mechanism  14  is removed out of the A-side mold  11 . Then, the A-side mold  11  is separated from the B-side mold  12  so that the injection barrel  3  with the needle  2  can be taken out of the core member  13 . 
         [0004]    However, because the collect mechanism  14  and the A-side mold  11  are two separated parts in the conventional insert mold  1 , a longitudinal axis of the collect mechanism  14  may not be in-line with a longitudinal axis of the mold space  112 . Hence, a longitudinal axis of the needle  2  may not be in-line with a longitudinal axis of the injection barrel  3  after the molten polymeric material is injected. 
         [0005]    Furthermore, a direction in which the flexible arms  141  move is perpendicular to a direction in which the collect mechanism  14  is inserted into or removed from the tapered receiving plenum  111 . Therefore, when the collect mechanism  14  starts to move along its longitudinal axis, the arms  141  may not immediately separate from the needle  2 , i.e. the arms  141  may still contact or hold the needle  2 . In this way, the needle  2  will wear contact surfaces of arms  141  to affect clamping preciseness, or the arms  141  may bend or even damage the needle  2 . 
         [0006]    Moreover, on the ground that the gate  113  is located near the broad end  114  of the mold space  112 , a converging end  115  of the mold space  112  may not be sufficiently filled with the molten polymeric material and thus be formed with defects of sink marks due to a drag of the molten polymeric material in the slender mold space  112 . Even if the molten polymeric material can flow to the converging end  115 , the pressure of polymeric material at the converging end  115  is still smaller than that at the broad end  114 . Consequently, strength and dimension stability at the converging end  115  of the injection barrel  3  is low. What is worse is that a portion of the resultant injection barrel  3  corresponding to the converging end  115  cannot firmly hold the needle  2  as a result of the low pressure. 
         [0007]    Besides, the core member  13  will be offset to incline to a longitudinal axis of a mold space  112  by the polymeric material injected into the mold space  112  through the single one gate  113 . 
         [0008]    In addition, the material of the contact surfaces of arms  141  is not so flexible to recover original shape after compression is released. The material has no sufficient durability against high pressure and temperature, neither. It is also difficult to precisely shape and thus fit the material of the contact surfaces to the arms. 
       SUMMARY OF THE INVENTION 
       [0009]    Accordingly, this invention relates to a mold assembly and method for manufacturing a syringe container which are substantially intended to obviate one or more of the problems due to the limitations and disadvantages encountered in the prior art. 
         [0010]    One object of this invention is to provide a mold assembly and/or method which can make a longitudinal axis of a cannula in-line with a longitudinal axis of a syringe barrel before and after molten polymeric material is injected. 
         [0011]    Another object of this invention is to provide a mold assembly and/or method which can avoid the clamping pieces from being worn out to affect clamping preciseness. 
         [0012]    Yet another object of this invention is to provide a mold assembly and/or method which can avoid the cannula from being bent or damaged by the clamping pieces during a molding process. 
         [0013]    A further object of this invention is to provide a mold assembly and/or method which can enhance the strength and dimension stability at a joint section of the syringe container. 
         [0014]    Another object of this invention is to provide a mold assembly and/or method which can facilitate the joint section to firmly hold the cannula of the syringe container. 
         [0015]    Yet another object of this invention is to provide a mold assembly and/or method which can maintain a longitudinal axis of a core in-line with a longitudinal axis of a mold cavity. 
         [0016]    Another object of this invention is to provide material for clamping pieces of a mold assembly and/or method which has properties as follows: flexibility for recovering original shape after compression is released, durability against high pressure and temperature, possibility to be precisely shaped, low thermal expansion, high elasticity for preventing from damaging the surface of the cannula, and nonstick property. 
         [0017]    These objects are achieved by mold assembly as defined by claim  1  and a method as defined by claim  11 . The dependent claims define preferred or advantageous embodiments of the mold assembly and method. 
         [0018]    Additional features and advantages of the invention will be set forth in the description which follows, and in portion will be apparent from the description, or may be learned by practice of the invention. The objectives and advantages of the invention will be realized and attained by the structure as particularly set forth in the written description and claims as well as illustrated in the appended drawings. 
         [0019]    To achieve these and other advantages and according to the purpose of this invention, as embodied and broadly described, a mold assembly for manufacturing a syringe container includes: a first set; a second set movable to abut against the first set to define a mold cavity therebetween; a core located in the mold cavity; and a first clamping piece and a second clamping piece for holding the cannula; characterized in that the first and second clamping pieces are respectively secured to the first and second sets. 
         [0020]    Another aspect of this invention directs to a method for manufacturing a syringe container with a mold assembly. The method includes: placing one end of a cannula into a port of a core; moving a first and second sets; injecting polymeric material into a mold cavity; separate the first and second sets from the core; and removing the syringe container out of the core; characterized in that: a first and second clamping pieces perform a function of holding the cannula the moment that the first and second sets are moved to abut against each other. 
         [0021]    These preferred embodiments can make a longitudinal axis of a cannula in-line with a longitudinal axis of a syringe barrel, avoid the clamping pieces from being worn out to affect clamping preciseness, and avoid the cannula from being damaged by the clamping pieces. 
         [0022]    Moreover, the mold cavity includes an engagement cavity corresponding to a joint section and a bore cavity corresponding to an annular section along a longitudinal axis of the core. The first set is formed with a first gate opening into the engagement cavity. The preferred embodiment can enhance the strength and dimension stability at the joint section of the syringe container, and facilitate the joint section to firmly hold the cannula of the syringe container. 
         [0023]    Furthermore, the second set is formed with a second gate opening into the engagement cavity. The first gate and the second gate are symmetrical about the longitudinal axis of the core 
         [0024]    The polymeric material is injected into the mold cavity through a portion of the mold cavity which accommodates one end of the cannula and/or one end of the core formed with the port. 
         [0025]    The polymeric material is injected into the mold cavity through the first gate and the second gate which open into the portion of the mold cavity and are symmetrical about a longitudinal axis of the core. 
         [0026]    The first gate and the second gate are respectively formed in the first set and the second set. 
         [0027]    A portion of the engagement cavity and a portion of the bore cavity are formed in the first set. Another portion of the engagement cavity and another portion of the bore cavity are formed in the second set. 
         [0028]    These preferred embodiments can maintain the longitudinal axis of the core in-line with the longitudinal axis of the mold cavity because the molten polymeric material flow into the mold cavity from two sides of the core and the pressures in the two sides of the core are the same. 
         [0029]    It is another preferred feature that the first clamping piece and the second clamping piece are made of a plastic material. This specific material for the clamping pieces has properties as follows: flexibility for recovering original shape after compression is released, durability against high pressure and temperature, possibility to be precisely shaped, low thermal expansion, high elasticity for preventing from damaging the surface of the cannula, and nonstick property. 
         [0030]    It is preferred that the first set further includes a first main block and a first sub-block. The second set further includes a second main block and a second sub-block. The bore cavity is formed between the first main block and the second main block. The engagement cavity is formed between the first sub-block and the second sub-block. 
         [0031]    The first set includes two of the first sub-blocks. The second set includes two of the second sub-blocks. The first gate is formed between the first sub-blocks. The second gate is formed between the second sub-blocks. 
         [0032]    The first clamping piece is formed with a first slot in which a portion of the cannula abuts against the first clamping piece. 
         [0033]    The first set is formed with a first trough communicating the first slot with the mold cavity. 
         [0034]    The core is formed with a port at one end thereof. One end of the cannula is arranged in the port and another end of the cannula is outside the mold assembly. 
         [0035]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide a further non-limiting explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]    The accompanying drawings, which are included to provide a further understanding of the invention and constitute a portion of the specification, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
           [0037]      FIG. 1  is an assembled sectional view illustrating a conventional insert mold; 
           [0038]      FIG. 2  is an assembled sectional view illustrating a syringe container manufactured by a mold assembly and method according to this invention; 
           [0039]      FIG. 3  is an assembled perspective view of the mold assembly according to this invention illustrating an open position; 
           [0040]      FIG. 4  is an exploded perspective view illustrating a first set of the mold assembly in the  FIG. 3 ; and 
           [0041]      FIG. 5  is an assembled sectional view of the mold assembly taken along a horizontal plane passing a longitudinal axis of a core according to this invention and illustrating a close position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Syringe Container 
       [0042]    As shown in  FIG. 2 , a syringe container  5  of this invention may include a hollow cannula  51  and a substantially cylindrical syringe barrel  52 . The cannula  51  is made of, for example, metal and may have a blunt end  511 , a sharp end  512 , a middle portion  513  between the blunt end  511  and the sharp end  512 , and a passage  514  through the cannula  51  from the blunt end  511  to the sharp end  512 . 
         [0043]    The syringe barrel  52  may include a wall  521  formed with, for example, polymeric material and a chamber  522  defined by the wall  521 . The profile of the syringe barrel  52  may show a wide end  523 , a narrow end  524 , an opening  525  defined by the wall  521  at the wide end  523 , an annular section  526  near the wide end  523 , and a joint section  527  extending to the narrow end  524  from another end of the annular section  526  opposite to the opening  525 . The joint section  527  may have a plurality of steps with different diameters respectively. 
         [0044]    The syringe barrel  52  may be molded around a portion of the cannula  51  such that the blunt end  511  of the cannula  51  is located in the chamber  522  of the syringe barrel  52 , a portion near the blunt end  511  of the cannula  51  is firmly secured by the joint section  527  of the syringe barrel  52 , the sharp end  512  is situated outside the syringe barrel  52 , and the passage  514  of the cannula is communicated with the chamber  522  of the syringe barrel  52 . A longitudinal axis  515  of the cannula  51  is in-line or in alignment with a longitudinal axis  528  of the syringe barrel  52 . 
       Mold Assembly 
       [0045]    As shown in  FIG. 3 , a mold assembly  6  for manufacturing the syringe container  5  of this invention may include a base  60 , a first set  61  movable relative to the base  60 , a first clamping piece  64  firmly secured to the first set  61 , a second set  65  movable relative to the base  60 , a second clamping piece  68  firmly secured to the second set  65 , and a pin-shaped core  69  firmly secured to the base  60  and disposed between the first set  61  and the second set  65 . 
         [0046]    Outer profile of the core  69  corresponds to inner profile of the syringe barrel  52 . The core  69  is made of, for example, metal and may be formed with a taped receiving port  691  at one end thereof opposite to the base  60 . 
         [0047]    As shown in  FIGS. 3 ,  4  and  5 , the first set  61  may further include a first main block  62  and two first sub-blocks  63  firmly secured to the first main block  62 . The first main block  62  is made of, for example, metal. The first main block  62  may be formed with a first bore cavity  621  whose longitudinal direction is parallel to a longitudinal axis  692  of the core  69  and a first recess  622  which opens into the first bore cavity  621  near the port  691  of the core  69 . Inner profile of the first bore cavity  621  corresponds to half outer profile of the annular section  526  of the syringe barrel  52 . 
         [0048]    The first sub-blocks  63  are made of, for example, metal. Each of the first sub-blocks  63  may be formed with a first engagement cavity half  631 , a first runner half  632  communicated with the first engagement cavity half  631  near the first bore cavity  621 , a first trough half  633  communicated with the first engagement cavity half  631  at another end thereof, and a first receptacle half  634  communicated with the first trough half  633  at another end thereof. Inner profile of the first engagement cavity half  631  corresponds to one-fourth outer profile of the joint section  527  of the syringe barrel  52  sectioned along the longitudinal direction. The structures of the two first sub-blocks  63  may be in a relation of plane symmetry. When the two first sub-blocks  63  are amounted into the first recess  622  and firmly secured to the first main block  62 , the two first runner halves  632  constitute a runner  632  between the two first sub-blocks  63 . The two first engagement cavity halves  631  also constitute a first engagement cavity  631  which opens into the first bore cavity  621 . The location where the first runner  632  connects the first engagement cavity  631  forms a first gate  635  to communicate the first runner  632  with the first engagement cavity  631 . The two first trough halves  633  and two first receptacle halves  634  respectively constitute a first trough  633  and first receptacle  634 , too. The first engagement cavity  631  and the first bore cavity  621  constitute a first mold cavity. Alternatively, two of the first sub-blocks  63  may be integrated into a one-piece member. Two of the second sub-blocks  67  may be integrated into a one-piece member as well. 
         [0049]    The first clamping piece  64  may be formed with a first slot  641 . The first clamping piece  64  is received in the first receptacle  634  and firmly secured to the two first sub-blocks  63  such that the first slot  641  is aligned with the first trough  633 . In other words, the first clamping piece  64  may be built in the first sub-block  63  or the first set  61 . The first clamping piece  64  is made of a plastic material, wherein this specific material for the clamping pieces has properties as follows: flexibility for recovering original shape after compression is released, durability against high pressure and temperature, possibility to be precisely shaped, low thermal expansion, high elasticity for preventing from damaging the surface of the cannula, and nonstick property. 
         [0050]    The first and second sets  61 ,  65  may be symmetrical with respect to a virtual parting plane  7  therebetween, on which the longitudinal axis  692  of the core  69  may be situated. Therefore, the second set  65  may include a second main block  66  and two second sub-blocks  67 . The second main block  66  may be formed with a second bore cavity  661  and a second recess  662 . Each of the second sub-block  67  may be formed with a second engagement cavity  671 , second runner  672 , second trough  673 , second receptacle  674  and second gate  675 . The second clamping piece  68  may be also formed with a second slot  681 . 
         [0051]    The first and second gates  635 ,  675  may communicate respectively with the first and second engagement cavities  631 ,  671  at different steps thereof. However, the first gate  635  and the second gate  675  are preferably symmetrical about the longitudinal axis  692  of the core  69 . 
       Process 
       [0052]    The method for manufacturing the syringe container  5  of this invention may include the following steps. First, an End of Arm in an automation system (not shown) transports the cannula  51  and places the blunt end  511  into the port  691  of the core  69  such that the longitudinal axis  515  of cannula  51  is substantially in-line with the longitudinal axis  692  of core  69 . 
         [0053]    Next, an injection molding machine (not shown) actuates the first main block  62  and the second main block  66  to move toward the core  69 . As mentioned above, the first and second sub-blocks  63 ,  67  are respectively secured to the first and second main blocks  62 ,  66 , and the first and second clamping pieces  64 ,  68  are respectively secured to the first and second sub-blocks  63 ,  67 . Therefore, when the first main block  62  abuts against the second main block  66 , the first sub-block  63  also abuts against the second sub-block  67  to define a close position of the mold assembly  6  and the virtual parting plane  7  between the first and second sets  61 ,  65 . In the close position, the first and second bore cavities  621 ,  661  constitute a bore cavity, the first and second engagement cavities  631 ,  671  constitute an engagement cavity, and the first and second troughs  633 ,  673  constitute a trough. Moreover, the engagement cavity and bore cavity constitutes a mold cavity, in which the core  69  is situated. 
         [0054]    In the close position, the first clamping piece  64  may or may not abut against the second clamping piece  68  but the first and second clamping pieces  64 ,  68  clamp the middle section  513  of the cannula  51  in the first and second slots  641 ,  681  with a proper force such that the longitudinal axis  515  of the cannula  51  is in-line with the longitudinal axis of the bore cavity and engagement cavity. The blunt end  511  is situated in the engagement cavity. The sharp end  512  protrudes outside the first and second clamping pieces  64 ,  68 . The inner diameters of the first and second troughs  633 ,  673  may be a little bit larger than those of the first and second slots  641 ,  681  so that the first and second sub-blocks  63 ,  67  hardly clamp the cannula  51 . 
         [0055]    After the first and second clamping pieces  64 ,  68  hold the cannula  51 , the End of Arm releases the cannula  51  such that the longitudinal axes  515 ,  692  of the cannula  51  and core  69  and the longitudinal axis of the mold cavity are in-line. Subsequently, molten polymeric material is injected through the first and second runners  632 ,  672 , the first and second gates  635 ,  675  and then into the empty engagement cavity and bore cavity. When the polymeric material in the mold cavity is cooled to a substantially solidified state, the first and second sets  61 ,  65  are separated along the parting plane  7  and define an open position of the mold assembly  6 . Then, the resultant syringe container  5  is taken out of the core  69 . 
         [0056]    This invention has been disclosed in terms of specific embodiments. It will be apparent that many modifications can be made to the disclosed structures and steps without departing from the invention. Therefore, it is the intent of the appended claims to cover all such variations and modifications that are within the scope of this invention.