Mould for closure caps with intermittent threads undercuts or hold-down lugs

A core, useful for moulding closure caps, each closure cap having a top, depending skirt substantially perpendicular to the top and having securing means secured to the inner wall of the skirt, said securing means comprising interrupted threads or hold-down lugs, said core having:

• a. a top forming portion;
• b. a plurality of skirt forming portions, circumferentially separated by a plurality of generally axially disposed channels in the outer peripheral wall of the core, each channel extending from at least a point intermediate the length of the core to the top forming portion and having its bed sloped generally radially inwardly in a direction towards the said top forming portion from a position adjacent the other end of the channel;
• c. a plurality of riser segments corresponding to the plurality of channels, secured for slidable movement within the channels relative to the core, each riser segment having an outwardly directed flange secured on the end of the segment opposite the top forming portion to permit simultaneous movement of the riser segments relative to the core from a position completely within the channel, having one end proximate the top forming portion of the core, to a position on the side of the top forming portion remote the other end of the core, each riser segment being of the same thickness as the corresponding depth of the channel in which it is situate when such end of the riser is proximate the top forming portion of the core so as to form on the outer periphery of such end of each riser a top forming portion to co-act with the top forming portion of the core when juxtaposed therewith and skirt and securing means forming portions;
• an annular ring secured about the periphery of said core and over said channels and said risers for securing said riser segments within said channels, and axially slidable closure cap ejector means within the core reciprocally moveable from a position within the core towards the top forming portion to a position on the side of the top forming portion remote the other end of the core.

A moulding system for manufacturing closure caps, each closure cap having a top, depending skirt and securing means secured to the inner wall of the skirt, said securing means comprising interrupted threads or hold-down lugs, including inlet means for introducing molten polymeric material into such system for use in forming the closure cap, comprising male and female mould portions, the female mould portion including means for co-acting with a core for forming the outer configuration of the top and the male mould portion including at least one core, each core having:

• a. a top forming portion;
• b. a plurality of skirt forming portion circumferentially separated by a plurality of generally axially disposed channels in the outer peripheral wall of the core, each channel extending from at least a point intermediate the length of the core to the top forming portion and having its bed sloped generally radially inwardly in a direction towards said top forming portion from a position adjacent the other end of the channel;
• c. a plurality of riser segments corresponding to the plurality of channels, secured for slidable movement within the channels relative to the core each riser segment having an outwardly directed flange secured on the end of the segment opposite the top forming portion to permit simultaneous movement of the riser segments relative to the core from a position completely within the channel having one end proximate the top forming portion of the core, to a position on the side of the top forming portion remote the other end of the core, each riser segment being of the same thickness as the corresponding depth of the channel in which it is situate, when such end of the riser is proximate the top forming portion of the core so as to form on the outer periphery of such end of each riser, a top forming portion to co-act with the top forming portion of the core when juxtaposed therewith and skirt and securing means forming portions;
• d. means securing said riser segments within said channels;
• e. means for longitudinally separating the male and female mould portions and for withdrawing the core relative to the risers in a direction away from the female mould portion for collapsing the risers radially inwardly, including means engaging the front and rear faces of the flanges at all times to support said flanges of the risers to permit radial movement of the flanges relative to said means engaging said faces of the flanges as the core is withdrawn relative to the risers but precluding any longitudinal movement of said flanges relative to said means engaging the faces of said flanges;
• f. means for ejecting the formed closure caps and means for reciprocating said male and female portions, and said core relative to said risers, into closed closure cap forming relation.

A moulding system for manufacturing closure caps, each closure cap having a top, depending skirt and securing means secured to the inner wall of the skirt, said securing means comprising interrupted threads or hold-down lugs, including inlet means for introducing molten polymeric material into such system for use in forming the closure cap, comprising male and female mould portions, the female mould portion including means for co-acting with a core for forming the outer configuration of the top and the male mould portion including at least one core, each core having:

• a. a top forming portion;
• b. a plurality of skirt forming portions circumferentially separated by a plurality of generally axially disposed channels in the outer peripheral wall of the core, each channel extending from at least a point intermediate the length of the core to the top forming portion and having its bed sloped generally radially inwardly in a direction towards said top forming portion from a position adjacent the other end of the channel;
• c. a plurality of riser segments corresponding to the plurality of channels, secured for slidable movement within the channels relative to the core, each riser segment having an outwardly directed flange secured on the end of the segment opposite the top forming portion to permit simultaneous movement of the riser segments relative to the core, from a position completely within the channel having one end proximate the top forming portion of the core, to a position on the side of the top forming portion remote the other end of the core, when each riser segment being of the same thickness as the corresponding depth of the channel in which it is situate, such end of the riser is proximate the top forming portion of the core so as to form on the outer periphery of such end of each riser, a top forming portion to co-act with the top forming portion of the core when juxtaposed therewith and skirt and securing means forming portions;
• d. means securing said riser segments within said channels;
• e. means for longitudinally separating the male and female mould portions and for withdrawing the core relative to the risers in a direction away from the female mould portion for collapsing the risers radially inwardly, including means engaging the front and rear faces of the flanges at all times to support said flanges of the risers to permit radial movement of the flanges relative to said means engaging said faces of the flanges as the core is withdrawn relative to the risers but precluding any longitudinal movement of said flanges relative to said means engaging the faces of said flanges;
• f. means for holding the formed closure cap out of contact with said riser segments when said riser segments collapse radially inwardly and said male and female mould portions are longitudinally separated;
• g. means for ejecting the formed closure cap and means for reciprocating said male and female mould portions, and said core relative to said risers, into closed closure cap forming relation.