KR20020089396A - Molded closure with flex areas and method - Google Patents

Abstract

The plastic cap 10 has a skirt 12 having an upper portion and an inner surface. To allow the skirt to expand radially outward in the circumferential direction when the inner surface of the skirt 12 is subjected to radially outwardly directed forces while the strip of cap is ejected from the mold 38 On the inner surface of the skirt 12, preferably, there are weak areas, bend areas 14 or bend panels. The method of molding the strip ejectable cap 10 is an average of the cap, in order to allow the cap to expand radially outward when the cap is ejected from the mold 38 with the damage of the thread reduced. Providing an outwardly extending member 42 on the core 38 of the mold to form an area 14 that is thinner than the thickness.

Description

Molded closure with flex areas and method for manufacturing same

There is a need for low cost containers and container components. The closure and cap components for the container can be manufactured by several processes, either by thermoforming or by compression (by itself or by overmolding) or by injection molding (by itself or by overmolding). Many such components are injection molding processes that are formed by injecting molten polymeric material into a mold cavity in the form of a cap or closure (hereinafter collectively referred to as "cap") under high pressure. Are manufactured. The injection molding apparatus includes a cavity, which is often described as a core, having one or more grooves extending radially inwardly over its surface to form one or more threads on the inner surface of the cap. It is formed between a male tooling and a female mold forming the outer surface of the cap. While the formed cap is on the core, it can be cooled. After the female tooling is removed from the cap, the cap is removed from the core. There are basically three ways to remove the formed cap from the mold tooling. Both methods are good because they remove the cap while damaging relatively little damage to its threads. The threaded cap is unscrewed or vice versa from the threaded tooling, or a core having a threaded groove therein is radially folded to remove the groove from the threaded portion of the cap and is an axial moving stripper, ie The stripper ring engages the lower rim of the cooling cap and strips the cap from the folded core. The methods prevent the threads on the inside of the cap from weakening and being damaged or deformed while removing the cap from the mold. In a third method, a stripper, which may be a knock out pin coming out of the unfolded core, engages the top wall of the cap and axially peels the top wall of the cap away from the core. This can be done by using a stripper ring to press the bottom surface of the cap. Since the core is not folded, when the cap engages the groove while the cap is axially peeled from the core, the cap of the cap is damaged and / or twisted. Weakened, damaged or deformed threads may be accommodated in some applications, but such threads may be suitable to initially or repeatedly adequately seal the container and / or to a torque that may be applied while screwing the cap into the container. It is generally undesirable because it can have a significant negative impact on the function of the cap.

Therefore, it is desirable to provide an improved cap. It would also be desirable to provide a low cost cap and a method and apparatus for manufacturing this low cost cap or improved cap.

It is therefore an object of the present invention to provide an improved cap.

Another object of the present invention is to provide a low cost cap.

It is a further object of the present invention to provide a low cost cap made of less material.

It is a further object of the present invention to provide a cap that can be made, for example, from about 30% to about 40% less material than a conventional cap of the same size.

It is a further object of the present invention to provide a cap which is designed to be axially removed or peeled off from a core, ie an unfolded core, with a threaded portion that is not damaged or twisted significantly or is grooved therein. .

It is a further object of the present invention that the threaded skirt of the cap is radially outward in order to avoid large damage or twist of the thread when the cap is removed axially from the male mold of the cap forming mold. It is to provide a cap having a thin bending area that can be bent and twisted or expanded.

Another object of the present invention is to provide an improved method and apparatus for forming a cap.

It is a further object of the present invention to provide an improved method and apparatus for forming said preferred cap.

It is a further object of the present invention to provide a method and apparatus which allow the above-described preferred caps to be manufactured in less time.

The present invention relates to a low cost molding closure or cap and a method and apparatus for manufacturing the same. The invention also relates to a molding closure or cap designed to eject the strip from the core of the mold.

1 is a front view of a preferred embodiment of the cap of the present invention.

FIG. 2 is a top view of the cap shown in FIG. 1. FIG.

3 is a bottom view of the cap of FIG. 1.

4 is a vertical cross-sectional view cut through the skirt portion and the threaded portion of the cap of FIG.

5 is a vertical section along line 5-5 of FIG. 2 of sheet 2 of the figures;

6 is a vertical section along line 6-6 of FIG. 2 of sheet 2 of the figures;

7 is a vertical section along line 7-7 of FIG. 2 of sheet 2 of the figures;

8 is a top perspective view of the cap of FIG.

9 is a bottom perspective view of the cap of FIG. 1;

9A is a top perspective view of a second embodiment of a cap of the present invention.

9B is a top view of the cap of FIG. 9A.

9C is an elevation view of the cap of FIG. 9A.

9D is a cross sectional view along line 9d-9d in FIG. 9B;

9E is a top perspective view of a second embodiment of the cap of the present invention.

9F is a top view of the cap of FIG. 9E.

9G is an elevation view of the cap of FIG. 9E.

9H is a vertical cross sectional view along line 9h-9h in FIG. 9F;

9I-9L are views similar to those shown in FIGS. 9A-9D of a fourth embodiment of the cap of the present invention.

9M-9O are views similar to those shown in FIGS. 9A-9C showing a fifth embodiment of the cap of the present invention.

9P-9S are views similar to those of FIGS. 9A-9D, showing a sixth embodiment of the cap of the present invention.

10 is a front view with a vertical cross-sectional portion through a portion of a closed mold set of an injection molding apparatus having an empty mold cavity for forming a cap of the present invention.

FIG. 11 is a vertical sectional view of the cavity cross section in the front view and the injection molding apparatus of FIG. 10 with the mold set open;

The present invention relates to a plastic cap, the plastic cap comprising: an upper portion; An annular skirt hanging on the upper portion and having an inner surface; Means for securing the cap to the neck of the container; Substantially provided on the cap so that when the radially outwardly directed force is applied to the inner surface of the skirt, for example when the cap is stripped out of the mold, the skirt can expand radially outward in the circumferential direction. It contains weak areas.

The invention also relates to a cap, the cap having an inner surface and an outer surface and composed of thermoplastic material, the upper portion; An annular skirt hanging on the upper portion and having an inner surface having a threaded portion extending radially inwardly; Although the cap does not have weak areas, the mold is provided with an outer surface with a thread-forming groove therein, in which the threading of the skirt is reduced or damaged by the groove of the core. In order to be strip-ejected from the core, the function of the skirt is increased to inflate radially outward and include a plurality of bend regions that are less than the average thickness of the cap. Preferably, the bent regions are the thinnest regions of the cap or are almost less than the minimum thickness of the rest of the cap excluding the thread. The bend regions are preferably about 1.2 to about 4 times thinner than the thickness of the cap excluding the thread. The bending regions may be bending panels and may be located on the inner and / or outer surface of the upper portion of the cap in the skirt and / or on or through the joint between the upper portion and the skirt. The skirt comprises a lower rim, wherein the bent regions comprise a plurality of circumferentially spaced panels and each of the bent panels are continuous from the upper portion of the cap or the upper portion of the skirt or sidewall to the lower rim of the cap. The bend regions or bend panels can be narrow and long in the skirt and extend in a direction substantially parallel to the longitudinal axis of the cap.

The threaded portion of the cap is preferably formed of segments arranged circumferentially from one another. Preferably, the threaded segment is not above or below the other threaded segment. The thread segments have integral parts and lead-in and lead-out parts, wherein the integral part of the segment does not axially overlap with the upper or lower part of the threaded segment. The bent regions can be spaced at equal intervals from each other with respect to the cap and can be almost no thicker than the average thickness of the cap. The bending panels may be located between the thread segments and may be thinner than the average vertical cross-sectional thickness of the skirt or thinner than the average vertical cross-sectional thickness of the skirt measured at the non-threaded portion of the skirt.

This allows the skirt to be primarily stretched in the bend regions, thereby increasing the function of the skirt when the skirt receives the same force than when an inner radially directed force is applied to the skirt without the bend regions. In order to further expand radially outwardly, the skirt comprises a portion of the first thickness and bending regions of a second thickness thinner than the portion of the first thickness.

The present invention relates to a method of molding a strip evacuable plastic cap, which method is characterized in that the inner surface of the cap is in communication with the upper wall and has a dependent annular skirt having an outer surface, an inner surface and an upper wall and a threaded portion. Shaping the cap in a mold set having a mold cavity formed by a core for forming and a female mold for forming an outer surface of the cap; Radius enough to allow the weak areas to be thinner than the average thickness of the cap, in order to allow the skirt to expand radially outwardly and thereby allow the cap to be stripped out of the mold while reducing damage to the threads Providing outwardly extending members on the outer surface of the core to form a weakly extending radially inward portion on the inner surface of the cap.

The skirt of the cap is spaced apart axially thin allowing the cap to bend or bend or expand in the radial axial direction when the cap is axially peeled away from the core of the mold cavity rather than unscrewed. Has a part The thread is preferably divided. It is discontinuous. Initial lead-in portions, terminal lead-out portions and segments of the other thread are circumferentially disposed from each other. The segments of the thread (different from the initial lead-in and final lead-out parts described above) are not directly underneath the other segments of the thread. This minimizes the damage or twist of the threaded portion.

The closure or cap (hereinafter “cap”) is a low cost cap. It uses a material as small as about 30% to about 40% to form the cap when compared to a conventional cap of the same size. Because of the use of reduced materials, molding, cooling and stripping times are reduced.

1 shows a preferred cap 10 of the present invention. Although the cap shown is for a tubular foldable dispensing vessel of 25.4 mm diameter, the cap of the present invention is not limited to any particular size and type of vessel. The cap 10 is an outer axial wall or skirt 12 having an upper wall, an upper panel or an upper portion 11 and an upper rim or ridge 13 and generally referred to herein by " It has thin, preferably substantially aligned, circumferentially spaced bending regions designated 14 ". The bend regions are thinner than the bend regions of the skirt. The wall thickness of the skirt of a conventional cap of the same size for a tube of 25.4 mm diameter is about 0.89 mm from the outer surface to the non-threaded portion of the inner surface of the skirt, while the thickness of the cap 10 is about 0.64 measured in the same area through the skirt. mm. The thickness of the thin bent region for the cap 10 is about 0.23 mm. The width of each bend area is about 1,27 mm. It should be understood that the thickness is good for the cap 10 having the size described herein for a 25,4 mm diameter tube with a neck having a diameter of 12.7 mm. Thus, if desired, one skilled in the art can adjust the size and thickness to suit the packaging situation.

It is also contemplated within the scope of the present invention that the bent region may have ribs formed therein, axially circumferentially or angled thereon. In addition, the one or more bend regions may themselves be weak to the bend region or bend regions, for example, a hole or gap with or without a web, and a filled or small area of reduced thickness or special material. Having portions with holes makes the portions of the bend area (s) or panel (s) even weaker.

There may be any suitable number of bend regions. Preferably, there may be two or more bend regions. The larger the number, the thicker it can be. However, in general, the larger the number, the smaller the circumferential length of the screw portion. Preferably, the bent regions are evenly or equally spaced from each other with respect to the circumference of the cap. This allows the cap to be balanced in the axial direction in the circumferential direction, for example providing a uniform torque against the rotation of the cap around the thread of the neck of the container. Each bending area need not have the same thickness.

Each bending region need not be of the same design or configuration as long as the object of the present invention is met. Thus, each bending area, any bending areas or all bending areas may be of any suitable size, shape, design or configuration. For example, the bent regions can be rectangular, trapezoidal, conical, truncated conical, circular, elongate rectangular, threaded, spiral or a combination of the same. Although less favorable, there may be some situations where bending regions may be desirable to surround, lead or follow one or more thread segments. As shown, preferably, the bent regions may be slightly truncated conical or tapered (so that the bottom thereof is widened), but the bent regions are rectangular. Preferably, the bent regions are arranged axially.

The bend regions can be any suitable height or length. Preferably, the bend regions are of uniform height and extend a sufficient height or length of the skirt of the cap. As described below, one or more bending regions of the skirt may extend radially across the top wall of the cap or into a portion of the top wall of the cap.

Consistent with the principal object of the present invention, one or more bending regions may be at any suitable position (s) of the cap. For example, one or more bending areas of the cap may be located only at the joint of the cap's skirt and the top wall or only at the top wall of the cap. If the bent regions are located on the top wall of the cap, it preferably extends to the joint of the top wall and more preferably into the skirt of the cap. For example, as shown in FIGS. 9E-9H, the top wall 11 ′ is preferably arranged in a starburst pattern of the top wall 11 ″ and the top rim of the skirt 12 ′. Or bend regions 14 'extending to ridge 13'.

The entire area of the top wall may be of reduced thickness and within the scope of the present invention allowing the skirt to be bent radially outward to facilitate stripping the sidewalls of the cap without twisting or damaging the cap. May be a bending area.

FIG. 2 is a top view of the cap of FIG. 1. FIG. 2 shows that the cap 10 has an upper wall 11.

3 is a bottom view of the cap of FIG. 1. The skirt 12 has an outer surface 16 and an inner surface 18.

4 is a vertical sectional view along the segment 20 of the threaded portion 22. The thread is preferably not necessarily a buttress thread. The thread is long enough to support itself during the strip ejection process. The thickness is preferably about 0.38 mm.

5 shows a segment 20 of the threaded portion 22.

6 and 7 show the corrugated threaded segment 20 supporting the bending regions 14. The figures show the lead-out portion 24 of the segment 20 covering the lead-in portion 26 of the lower segment 20. The lead-in and lead-out portions taper (gradually thinner) radially outward towards the inner surface of the skirt, and therefore do not cause interference or stripping problems.

8 and 9 are perspective views of the cap 10. 9 shows that the bend region 14 is located between the threaded segments 20 and the bend regions preferably extend to the bottom edge or rim 17 of the skirt.

9A-9D show generally that the bending panel 14 'extends radially from the outer surface 16' of the skirt 12 'radially into the wall of the skirt 12' of the cap 10 '. A second embodiment of the cap of the present invention, designated as "", is shown. The bending panel 14 'extends from the top edge or rim 13' to the bottom edge 17 'of the skirt. The bending panels are substantially parallel to the axis of the cap 10 'and spaced equally about the circumference of the cap.

Figures 9E-9H generally show a third embodiment of the cap of the invention, designated by the reference "10" ". The cap 10" is a cap 10 "extending downward and the top wall 11 Has a plurality of bending panels arranged in a starburst or radial pattern of " The illustrated bend panels 14 'are blocked by the central portion 15' which is the normal thickness of the top panel 11 ". Although the bend panels 14 'are shown as possible in the figures, the skirt 12 ') Or into the rim 13' of the side wall or the bending panels 14 'cannot be joined. As shown in Figs. 9E-9H, one or more bending panels may be arranged on the top surface of the portion 11 ", Providing downward into the outer surface or upward into the inner surface of the portion 11 "assists in meeting the object of the present invention because it weakens the hoop strength of the skirt or sidewall. Bending panel 14 ' ) May extend into each other by removing the central portion 15.

9I-9L show a fourth embodiment of the cap of the present invention, generally designated by the designation “10” '“. The cap 10"' has a skirt 12 "'with an upper panel 11"'. Do not have an upper rim to directly join In this embodiment, the top panel 11 "'and the bending panel 14"' of the skirt 12 "'are adjacent to each other and form one continuous bending panel. The bending panel configuration is a cap from the core of the mold. In order to facilitate strip ejection, the opposing portions on both sides on the bending panel can be moved away from each other in a hinged manner from the area adjacent the top panel 11 "'.

9M-9O generally show a fifth embodiment of the cap of the present invention, designated by the symbol “100”. This embodiment shows that the bending panel 14 'can advantageously be used with the continuous bending panel 14 "', the former allowing the skirt to expand radially outward in the circumferential direction, the latter This allows the skirt to be hinged adjacent to the top panel 11 "', thereby facilitating or jointly permitting strip ejection of the cap 100 from the core of the mold.

9P-9S show a sixth embodiment of the cap of the present invention, generally designated by the symbol "100 '". The cap 100 ′ has a bending panel 114 extending downward through the joint 117 from the outer periphery of the top panel 111 into the outer surface of the top of the skirt 112. This configuration of bending panels circumferentially arranged around the joint of the top wall and the skirt forms pivot points, which allow the skirt to move outward to facilitate the ejection of the strip. Bending panel 114 may be any suitable length of top wall and skirt. For example, the bend panels may consist of simply a plurality of circumferentially spaced notches (not shown) formed in the joint 117 between the top panel 111 and the skirt 112. Thus, the embodiment of FIGS. 9A-9S can be any suitable size, configuration, and location where the bending panels meet the purpose of the present invention and reduce the hoop strength of the sidewall or skirt to facilitate strip ejection of the cap.

The main concept of the present invention is that the cap of the present invention can be easily peeled off in the axial direction from the molded male mold or core. As shown in FIGS. 10 and 11, the male mandrel 38 has a groove 40 disposed therein in wave shape and the wave segments of the threaded portion are formed. Mandrel 38 has radially outwardly extending ribs 42 protruding from its outer surface. 10 shows a closed mold set before injecting plastic into the mold cavity. FIG. 11 shows the cap and the open mold set peeled off the mandrel after the stripper plate 44 has moved upward to engage the bottom edge of the skirt 12 of the cap. Although male presses or cores are described with injection molding apparatus, it should be understood that the caps and improved apparatus and methods of the present invention may be used with compression molding and thermoforming apparatuses and methods.

According to the invention, the cap can be easily peeled off the mandrel because the overall wall thickness has been reduced and especially the bending area is very thin. This allows the skirt to expand radially outwards thereby allowing each thread to leave the groove, where each thread is formed and axially peeled off the mandrel without encountering another groove on the groove. The threaded part is not largely damaged. The thread preferably has an extended axial length that can act to provide sufficient torque to screw the cap to the neck of the container, even if the thread segment is partially damaged.

Those skilled in the art of strip ejection of the cap will understand how to apply the configurations disclosed herein to other sizes, types and applications. Factors that can be applied, considered and balanced include wall or skirt strength, namely the column strength required for a particular application, the material used, the overall diameter of the cap, the number of bend regions, the size (height, thickness and width). And size, thickness and profile or shape of the cap and thread. The height and taper of the side wall of the cap or the threaded skirt can also be a factor, as this also adversely affects the amount of expansion of the skirt and the ease of stripping. Other correlation factors include whether the cap has a continuous thread or segment thread, the level of stripping force, the screw twist and the torque holding force required for the application to be considered.

Softened areas, bent areas or panels are preferably the thinnest areas of the cap. They are almost no thicker than the minimum thickness of the cap, except for the thread, and preferably, are about 1.2 to about 4 times thinner than the thickness of the cap, except for the thread.

Thin bending areas of the skirt, here the thickness of the panels, are preferably and generally the thinnest parts of the skirt. Bend regions or panels are preferably and generally thinner than the average vertical cross-sectional thickness of the skirt. For the skirt 12 of the cap 10, preferably and in fact the bend regions 14 are thinner than the average thickness of the skirt measured at the non-threaded portions of the skirt. The bend regions 14 are also preferably thinner than those measured from the thinnest parts of the other state of the skirt, ie the depth of the groove of the serrated surface of the cap to the inner, non-threaded surface of the skirt. Preferably, the bent regions are generally no thicker than the minimum thickness of normal sidewalls, and preferably, are not nearly thick. Bending areas designed to concentrate are manufactured in weak areas that provide greater flexibility or provide more flexibility than the rest of the skirt, the skirt has reduced hoop strength and the cap has no bending area and small forces and small thread twist Or the goal is to be able to peel off without being destroyed. In the cap 10, the bend regions 14 are weaker than the serrated portions of the cap.

The bend regions 14 are preferably thin enough to meet the purposes of the present invention, but are so thin that they do not tend to break or break during torque application or stripping. The bend region 14 need not have a uniform thickness. And each bent region 14 need not have the same thickness as the other bent regions.

The bend regions 14, especially when very thin, preferably occupy only a small part, ie a part around the circumference of the cap or less than about 50% of the circumference width. Alternatively, the cap may be too weak and / or have no thread sufficient to sufficiently engage the mating thread (s) on the neck of the container or to hold the cap on the container or to properly hold the container. Cannot have a hoop strength suitable for sealing. In a preferred embodiment using segment threads, the bend regions 14 are preferably narrower than the shortest arcuate size or width of the segments of the threads. Although it is common practice that the wider the bend area or panel, the greater the flexibility of the skirt, it is within the scope of the present invention to excessively limit the number of thread segments or excessively weaken the sidewalls of the skirt. It is contemplated to provide many narrow axial bending panels. In a wider bend area or panel, the thicker the panel between the bend areas, the more free it is to bend out or bend or pivot outwardly, independently or in combination, to avoid damage or twist of the single or multiple threads. Preferably, the skirt should be able to inflate or pivot from the weakest point near the top wall of the cap by a distance that is at least half the radial thickness of the thread on the inner surface of the cap. Preferably, the skirt can be inflated by a distance substantially greater than or greater than the overall radial thickness of the thread, threads or thread segments.

The bend regions preferably extend radially outward from the inner surface of the cap toward the outer surface of the cap. However, it is also included within the scope of the present invention that one or more or all of the bend regions may extend from the outer surface of the cap towards the inner surface radially. Combinations of this type of bending regions may be used.

The caps of the present invention can be very suitable for articles of manufacture packaged at low internal pressures. Caps can be well suited for packaging applications and containers with a limited lifetime. It is to be understood that the closure or cap herein includes any cover for the opening of the item or container. It is also contemplated that the closure or cap comprises a closure having a base and flip top cap, secured to the cap by means of living or other hinges or straps. Closures or caps of the present invention are not limited to means by which the cap is fixed on or held on an item or container. Thus, the closure or caps of the present invention may have any suitable means for securing the closure or caps to the base of the cap or to the neck of the container which are alternately secured to the container. The sidewalls or skirt of the cap are non-screwable and have radially inwardly extending members, i.e. beads for engaging or retaining frictional snaps with other parts of the item or container or cooperating parts of the neck. It may include.

The cap of the invention is preferably screwed on the inner surface of the skirt. Any suitable type of screwing may be used. The thread profile may be round or V-shaped or angled, buttless or modified buttress-shaped or a combination of the above or other forms. The threaded engagement surface of the buttress thread is preferably tapered at an angle of about 15 degrees to about 25 degrees with respect to the inner surface of the skirt of the cap. The threads are preferred because they provide high torque durability, called V-shaped or round-shaped threads. Although the latter is easier to peel off from the core, the torque durability is low and cannot provide sufficient sealing. When used with the cap of the present invention using modified buttressed threads, the advantage is that it can be easily peeled off the core with minimal torsion or damage.

Although the threads used in the cap of the present invention may be continuous in a state where the depth or profile does not change or is changed, preferably, the threads are wave-shaped in a state where the depth or profile does not or does not change or It is segmented. The thread segments may be distributed uniformly or nonuniformly around the circumference of the skirt of the cap. The bend regions 14 may preferably extend axially between the thread segments. The pitch of the threads or thread segments is rough rather than fine, and the divided strained buttress thread of the cap 10 is about 12 turns per 25.4 mm. It is generally acceptable to provide at least one turn of screw engagement for a uniform balanced torque and a pull down force in a uniform axial direction. For the embodiment with the divided thread shown in the figure, the thread segments preferably extend circumferentially around the skirt for the entire two complete turns, but about half of the length of the thread is removed. One divided thread extends over a distance of two thread turns (720 degrees), with a net result similar to one complete turn of the continuous thread. Preferably, no part of the complete thread segment is axially overlapping (top or bottom) with other parts of the other complete thread segment. By complete threaded segment is meant a segment portion of complete axial height and radial thickness. Thus, at the segment threaded portion 22 of the cap 10, preferably, any portion of the segment 20 of the threaded portion 22 different from the tapered lead-in or lead-out portion is above or below it. It does not axially overlap with the complete threaded segment. In the cap 10, the complete thread thickness is about 0.38 mm measured from the inner surface of the skirt. The complete thread height of the segment is about 1.07 mm. The overlapping of some complete threaded segments may facilitate the peeling of the cap from the core easily, unless it is angled further at an angle to the vertical, and / or if no tapered core is used. It can be tolerated with increased damage or torsion. The skirt of the cap 10 of the present invention may be at an angle of about 0 to 4 or 5 degrees, preferably about 3 degrees and more preferably at an angle of about 2.5 degrees. The larger the angle, the easier it is to peel off the cap from the core, but the torque durability of the thread relative to the mating thread of the container becomes smaller. Too steep taper reduces torque, cap holding force and sealability.

Any suitable cap may, for example, have areas that are weak with respect to the bending areas according to the invention. The cap may have a skirt, a side wall or an annular ring or a shell having a vertical, conical or tapered threaded inner surface. The outer shape of the cap may be any suitable shape, ie round, oval or square. The cap may be a flip-top, dispensing or other single or composite component item. The wall thickness may or may not be uniform. For example, it may be ribbed or serrated or patterned. The cap may include or be used in combination with child resistant or tamper evident forms. Weak areas, eg, bent areas, may be such shapes or shapes or may be part of such shapes.

The cap may be formed of any suitable material (s) usable to form the cap. Examples of materials, however, include copolymers including high, medium, low, very low and extremely low densities of polyethylene, polypropylene, ethylene-propylene copolymers, ethylene polymers and propylene, and polyesters, filled or unfilled. For example, polyethylene terephthalate is included. Preferably, the cap consists of one or more thermoplastic materials. The cap may be a single or multiple layer, barrier or non-barrier. The material (s) of the cap may comprise a polymer made from a single site catalyst system, for example a metallocene catalyst. Suitable such materials for forming the cap are described in US patent application Ser. No. 09/144/713, filed Sep. 1, 1998, the publication of which is incorporated herein by reference.

The device of the invention may be any suitable device for molding the cap. The device includes a female mold and a core operable therein for forming a mold cavity for forming a cap. The female die or core or both may be modified or formed to form bend regions on the inner, outer or both sides of the cap. Preferably, the core has an outer surface having a plurality of groove segments radially formed into the surface for forming on the core, and the cap has an annular wall or skirt having an inner surface with divided threads extending radially inwardly. Has Segments of the thread are formed in the groove segments. The groove segments of the core preferably have a first or major groove having a progressively deeper tapered or ramped lead-in portion and a progressively shallower tapered or ramped lead-out portion. And a trailing terminal groove segment. Preferably, the complete portion of the groove segment does not axially lie above or below the other complete portion of the other groove segment. The complete portion of the threaded segment is the threaded segment portion, not the lead-in or lead-out portion of the threaded segment. The core of the devices of the invention may be a strip core, a folded core, a threaded core or a combination thereof. The outer surface of the core of the present invention may generally be tapered at an angle of about 0 degrees to about 4 degrees or 5 degrees, preferably about 3 degrees and most preferably about 2.5 degrees. If a bending panel is provided on the outer surface of the cap, the tool is suitable for forming a bending panel of the desired type, shape, or the like on the outer surface of the cap, so that a radially outwardly extending rib or nub or the like can be provided. Equipped. Preferably, the bending panels extend axially along the skirt at a circumferential position between the thread segments.

This application is related to US divided applications entitled “Improved Containers and Methods and Apparatus for Forming the Containers”. This application was filed on the same date as the main application and was assigned to the same assignee.

Strip ejection of the thread closure reduces the molding cycle when compared to the unthreaded type. Thin wall “bending” areas allow the cap to twist during strip ejection. The modified buttress thread is good because it provides a high torque when compared to the "round" thread. The discontinuous threads are molded on the tapered wall and waved to ensure that the next pitch of the threads during the strip ejection operation does not damage the thread walls.

The discontinuous threads are wave-like but provide a balanced torque and a uniform axial pulling force when a force is applied to the continuous mating threads of the vessel.

The cap is designed to eject the strip. Typical strip mold closures use continuous round threads on taper. The closure of the present invention is designed with a modified buttress thread to provide better torque holding force when a force is applied to the container. The modified buttress thread is preferably split on the tapered wall in a pattern that does not allow one thread to be placed directly on the other. This pattern allows the strip to be ejected with minimally damaged / twisted threads. The closure is preferably bent outward during discharge due to thin segments of symmetry, preferably in a wall parallel to the axis of the cap. The segments are designed to bend during discharge (hot polypropylene), but recover while cooling. The continuous cap wall provides sufficient hoop strength to maintain the required threaded engagement, torque, and seal when force is applied to the vessel.

Claims (31)

An upper portion; An annular skirt hanging on the upper portion and having an inner surface; Means for securing the cap to the neck of the container; A plastic cap comprising substantially weak areas provided in the cap such that when the radially outwardly directed force is applied to the inner surface of the skirt, the skirt can expand in the circumferential radially outward direction. A cap having an inner surface and an outer surface and composed of a thermoplastic material, An upper portion; An annular skirt hanging on the upper portion and having an inner surface having a threaded portion extending radially inwardly; From a mold core having an outer surface with a thread-forming groove therein, with the cap having a reduced threaded groove or damage to the thread of the skirt by the groove of the core, rather than without the weak areas. A cap comprising a plurality of bend regions that are expanded radially outwards by increasing the function of the skirt so that it can be strip-exposed and having a thickness less than the average thickness of the cap. The cap of claim 2, wherein the bent regions are the thinnest regions of the cap. 3. A cap as claimed in claim 2, wherein the bent regions are substantially less than the minimum thickness of the rest of the cap except for the threaded portion. The cap of claim 2, wherein the bent regions are at least about 1.2 to about 4 times thinner than the thickness of the cap except for the threaded portion. The cap of claim 2, wherein the bent regions are located on top of the cap. 3. The cap of claim 2, wherein said bent regions are located in a skirt. 3. The cap of claim 2, wherein there is a joint between the skirt and the upper portion of the cap, wherein the bent regions are located in the joint. The plastic cap of claim 1, wherein the weak areas are bending panels. 3. The cap of claim 2, wherein said bending regions are bending panels. The cap of claim 10, wherein the bending panels are formed on an inner surface of the skirt. The cap of claim 10, wherein the bending panels are formed on an outer surface of the skirt. The cap of claim 10, wherein the bending panels are formed in an upper portion of the cap. The cap of claim 10, wherein the upper portion of the cap has an outer surface and an inner surface, and the bending panels are formed on the outer surface of the upper portion of the cap. The cap of claim 10, wherein the upper portion of the cap has an outer surface and an inner surface, and the bending panels are formed on an inner surface of the upper portion of the cap. 3. The cap of claim 2, wherein said skirt comprises a lower rim, said bent regions comprising a plurality of circumferentially spaced panels and each bent panel is continuous from an upper portion of the cap to a lower rim of the cap. 3. The cap as claimed in claim 2, wherein the bent regions are narrow and long bend panels, which bend panels are formed in the skirt and extend in a direction substantially parallel to the longitudinal axis of the cap. 18. The cap of claim 17, wherein the width of the bend panels taper inwardly when extending toward the upper portion of the cap. 3. The cap of claim 2 wherein said threaded portion is formed from segments arranged circumferentially from one another. 20. The cap of claim 19, wherein said threaded segment is not above or below another threaded segment. 20. The cap of claim 19, wherein said threaded segment is not directly under another threaded segment. 20. The cap of claim 19, wherein said thread segments have integral portions and lead-in portions and lead-out portions, wherein the integral portion of the segment does not axially overlap with an upper portion or an underlying portion of the threaded segment. 20. The cap of claim 19, wherein said bending panels are located between threaded segments. 20. The cap of claim 19, wherein the bending panels are spaced at equal intervals from each other with respect to the cap. The cap of claim 10, wherein the bending panels are formed in the skirt and thinner than the average vertical cross-sectional thickness of the skirt. The cap of claim 10, wherein the bend panels are thinner than the average vertical cross-sectional thickness of the skirt measured at the non-threaded portions of the skirt. The cap of claim 10, wherein the bent regions are no thicker than the average thickness of the cap. An upper portion; Suspended from this upper part and having a side wall with a threaded portion extending radially inwardly in order to secure the cap to the threaded neck of the container, the complete segmented portion not axially overlapping with the portion of the other complete segment A cap comprising a skirt consisting of complete segments spaced circumferentially away from each other. 29. The method of claim 28, wherein the skirt is allowed to be stretched in the bent regions so that an inner radially outwardly directed force is applied when the skirt receives the same force than when applied to the skirt without the bent regions. A cap having a portion of a first thickness and bending regions of a second thickness thinner than the portion of the first thickness, in order to increase the function of the skirt to further expand radially outward. 30. The cap of claim 29, wherein the bent regions comprise bend panels. A method of molding a strip ejectable plastic cap, A mold catch formed by a core for forming the inner surface of the cap and a female press for forming the outer surface of the cap, the cap having a dependent annular skirt having an outer surface, an inner surface, an upper wall and a thread, and in communication with the upper wall. Molding the cap in a mold set with bits; Radius enough to allow the weak areas to be thinner than the average thickness of the cap, in order to allow the skirt to expand radially outward and thereby allow the cap to be stripped out of the mold with reduced damage to the threads Providing outwardly extending members on the outer surface of the core to form a weakly extending radially inward portion on the inner surface of the cap.