MXPA02008932A - Molded closure with flex areas and method. - Google Patents

Abstract

A plastic cap (10) having a top portion and a skirt (12) with an interior surface. There are weak areas, flex areas (14) or flex panels, preferably in the interior surface of the skirt (12), to allow the skirt to expand circumferentially radially outward when the interior surface of the skirt (12) is subjected to a radially outwardly directed force as during stripminus;ejection of the cap from mold tooling (38). A method of molding the strip ejectable cap (10) includes providing outwardly extending members (42) on the core (38) of the mold tooling to form areas (14) in the cap that are thinner than the average thickness of the cap to allow the cap to expand radially outward when the cap is strip ejected from the mold tooling (38) with reduced smearing of the thread.

Description

MOLDED CLOSURE WITH FLEXION AREAS AND METHOD FIELD OF THE INVENTION The present invention is directed to a low cost molded closure or lid, and to methods and apparatus for producing the same. The invention is also directed to a molded closure or lid that is designed to be extracted by ejection from the center of a mold.

BACKGROUND OF THE INVENTION There has been a need for low cost containers and container components. The components of closures and covers for containers can be manufactured by various processes, for example, thermoforming, or by compression (alone or by (or with) molding) or injection molding (alone or with overmolding). Many of these components are manufactured by injection molding processes which involve the injection of high pressure molten polymer material into the cavity of a mold having the shape of the closure or lid (hereinafter collectively referred to as "lid"). ") that will be formed. The injection molding apparatus includes a cavity that is formed between a male tooling, often referred to as a center, having one or more slits that extend radially inwardly in its Ref: 141636 surface to form one or more threads on the inner surface of the lid, and female tooling that forms the outer surface of the lid. The formed lid is allowed to cool while remaining on the center. After the female tooling is pulled out of the lid, the lid is removed from the center. Basically there have been three methods to remove the formed lid of the mold tooling. Two methods are preferred because they remove the lid with relatively minor damage to their threads. The threaded cap is unscrewed from the threaded tooling or vice versa, or the center with the threaded groove on it collapses radially to remove the groove from the cap thread and an axially desoldering shaker, for example, a release ring, engages to the lower ring of the cooled lid and the collapsed center lid is removed from the mold. These methods prevent the threads inside the lids from weakening, damaging or deforming during the removal of the tooling covers. In the third method, a desmoldador, the cuai can be a desmoldado pin that is removed through a center without collapsing, hooks the upper wall and demolishes axially from the center. This can also be effected by the use of a release ring that pushes the lower surface of the lid upwards. Since the center does not collapse, the thread of the lid is erased and / or distorted when the thread engages the indentation while the lid is demoulded axially from the center. The weakened, damaged or deformed threads are acceptable for some non-demanding or less demanding applications but generally those threads are undesirable because they can significantly negatively affect the torque that can be applied when the cover is screwed onto a container, and / or the capacity of the cap for initially or repeatedly sealing the container appropriately. It would be desirable to provide an improved lid. It would also be desirable to provide a low cost cap, as well as improved methods and an apparatus for the production of improved or inexpensive covers. Therefore, an object of the present invention is to provide an improved lid. Another object of the present invention is to provide a low cost cap. Another object of the invention is to provide a low cost cap that is produced with less material. Another object of the invention is to provide a lid that can be manufactured, for example, from about 30% to about 40% less material than it would be with a conventional lid of the same size. Another object of the invention is to provide a lid that is designed to be removed axially or demoulded of a center, for example, a non-collapsed center, which has a threading or other slit formed in it, without significantly deleting or distorting the thread. Still another object of the invention is to provide a lid having thin flexible areas that allow a threaded side wall of the lid to flex, distort or expand radially outward to prevent significant erasure or distortion of the thread when the lid is removed axially of the female tooling of the cap forming mold. Still another object of the invention is to provide improved methods and an apparatus for the formation of a lid. Still another object of the invention is to provide improved methods and an apparatus for the formation of a desired lid mentioned above. Still another object of the invention is to provide methods and an apparatus that allow a desired aforementioned cover to be manufactured in less time.

BRIEF DESCRIPTION OF THE INVENTION The present invention is directed to a plastic lid, comprising a lid portion, an annular side wall that depends on the lid portion and having an internal surface, means for securing the lid to the neck of a lid. vessel, and substantially weak areas provided in the lid to allow the side wall to expand radially outward in a circumferential manner when the inner surface of the side wall is subjected to a radially outwardly directed force, for example, when the lid is removed from the mold by ejection of the tool from the mold . The invention is also directed to a lid comprising a thermoplastic material and having an inner surface and an outer surface, comprising an upper portion, an annular side wall that depends on the upper portion, the side wall has an internal surface that has a thread extending radially inward, and a plurality of flex areas that are less thick than the average thickness of the lid, and which increase the capacity of the side wall to expand radially outwardly such that the lid can be demolded by ejection of a mold center having an external surface with a slit forming a thread therein, with a reduced erasure or distortion of the side wall due to the center slit in comparison if the lid had no weak areas. Preferably the bending areas are the thinner areas of the lid, or are substantially less thin than the minimum thickness of the rest of the lid excluding threading. The flex areas are preferably about 1.2 to about 4 or more times thinner than the thickness of the lid excluding threading. The flexing areas may be flex panels and may be located on the inner and / or outer surface of the upper portion of the cap, on the side wall, and / or on the inside or through the joint between the upper portion and the side wall. The side wall may include a lower ring, and the flexing areas may comprise a plurality of circumferentially spaced panels, each running continuously from the upper portion of the lid or from the top of the side wall or side wall to the lower ring of the lid. The bending areas or bending panels may be narrow and elongate in the side wall and may extend in a direction substantially parallel to the longitudinal axis of the lid. The widths of the flex panels can taper inwardly as they extend toward the top portion of the lid. The thread of the lid is preferably formed of segments that are alternately circumferentially of one another. Preferably, no thread segment lies or underlies another thread segment. The thread segments may have full portions and portions of input groove and output groove, wherein no full portion of a segment axially overlaps a portion. complete that lies or underlying a thread segment. The flexing areas may be equally spaced from one another around the cap, and may be substantially less thin than the average thickness of the cap. The bending panels may be located between the thread segments, and may be thinner than the vertical cross-sectional thickness of the sidewall, or thinner than the vertical cross-sectional thickness of the sidewall measured in the non-threaded portions. of the side wall. The side wall can have portions of a first thickness, and flex areas of a second thickness that are thinner than the first portions, to allow the side wall to stretch mainly in the flex areas and thus increase the capacity more of expansion of the side wall radially outwardly when the side wall is subjected to an internal force directed radially outward in comparison if the same force were applied to said side wall without the areas of flexion. The invention is also directed to a method of molding an ejection-releasable lid, which comprises molding a lid into a set of tools having a mold cavity formed by the female tooling for the formation of the surfaceexternally of the lid and by means of a center for the formation of the internal surface of the lid, in such a way that the lid will have an external surface, an internal surface, an upper wall, and an annular side wall dependent with a thread and that is in communication with the upper wall, provided with members extending radially outwardly on the outer surface of the center to form weakened areas extending radially inwardly on the inner surface of the lid, the members extend radially outwardly sufficiently such that the weakened areas are thinner than the average thickness of the lid, to allow the side wall to expand radially outwardly and thus allow the lid to be demolded by ejection of the tooling from the mold with reduced erasure of the thread.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front elevation of a preferred embodiment of the lid of the invention. Figure 2 is a top plan view of the lid shown in Figure 1. Figure 3 is a bottom view of the lid of Figure 1.

Figure 4 is a vertical sectional view taken through a thread segment and a portion of the side wall of the lid of Figure 5. Figure 5 is a vertical sectional view taken along the line 5-5. from figure 2 of sheet 2 to the drawings Figure 6 is a vertical sectional view taken along line 6-6 of figure 2 of sheet 2 of the drawings. Figure 7 is a vertical sectional view taken along line 7-7 of Figure 2 of sheet 2 of the drawings. Figure 8 is a top perspective side view of the lid of Figure 1. - * Figure 9 is a bottom perspective view of the lid of Figure 1. Figure 9A is a top perspective view of a second embodiment. of the lid of the invention. Figure 9B is a top view of the cover of the Figure 9A Figure 9C is an elevation view of the cover of Figure 9A Figure 9D is a sectional view taken along the line 9D-9D of the Figure 9B. ^ Figure 9E is a top perspective view of a second embodiment of the lid of the invention. Figure 9F is a top view of the lid of Figure 9E. Figure 9G is an elevation view of the lid of Figure 9E. Figure 9H is a vertical sectional view taken along the line 9H-9H of Figure 9F. Figures 91 to 9L are views similar to those shown in Figures 9A to 9D, of a fourth embodiment of the cover of the invention. Figures 9M to 90 are views similar to those shown in Figures 9A to 9C, which show a fifth embodiment of the cover of the invention. Figures 9P to 9S are views similar to those shown in Figures 9A to 9D, which show a sixth embodiment of the cover of the invention. Figure 10 is a front elevation, with portions in vertical section through a portion of a closed tool assembly of an injection molding apparatus having an empty mold cavity for forming a lid of the invention. Figure 11 is a vertical section of the injection molding apparatus of Figure 10 shown with the tool set open, and its cross section of the cavity in front elevation.

The side wall of the lid has spaced axial thin portions that allow the lid to distort, flex or expand radially outwardly when the lid is axially demoulded, rather than unscrewed, from the center of a mold cavity. The thread is preferably segmented, that is, discontinuous. The thread segments, other than the input groove and output groove portions, are alternately circumferential to one another. None of the segments of the thread (different from the portions of the inlet groove and the outgoing groove mentioned above) directly underlie axially in another segment of the thread. This allows minimal erasure or distortion of the thread. The closure or lid (hereinafter "lid") is a low cost cap. Use significantly less material, often about 30% to about 40% less material, to form the lid compared to a conventional lid of similar size. Due to the reduced material used, the time of molding, cooling and demolding are reduced.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows a preferred cover 10 of the invention. Although the lid shown is for a 25.4 mm (1 inch) collapsible spout tubular container diameter, the lid of the invention is not limited to any particular size or type of container. The lid 10 has an upper wall, a top panel or upper portion 11, an external axial wall or side wall 12 with an upper edge or flange 13 and thin flexing areas spaced apart preferably substantially aligned in circumferential shape, here designated in general as 14. The flex areas are thinner than the less flexible areas of the side wall. While the wall thickness of the side wall of a conventional lid of the same size for a 25.4 mm (1 inch) diameter tube is 0.889 mm (0.035 inches) thick, the outer surface of the non-threaded portion of the internal surface of the side wall, the thickness of the lid 10 is approximately 0.0635 mm (0.025 inches) thick, measured in the same area through the side wall. The thickness of the thin flex area for the lid 10 is approximately 0.229 mm (0.009 inches). The thickness of each bending area is approximately 1.27 mm (0.050 inches). It should be understood that these thicknesses are preferred for a lid 10 having the dimensions described herein for a tube 25 millimeters (one inch) in diameter having a neck whose diameter is 1.27 mm. (0.5 inches). Therefore, if desired, someone with Experience in the art can adapt these dimensions and thicknesses to adjust the packaging application. It is contemplated that it is included within the scope of the present invention that the bending areas may have ribs axially circumferentially or angularly in, on, or through them. Also, one or more of the flex areas themselves may have weakened areas in relation to the area or areas of flexion, eg, holes or gaps, with or without plots, areas of reduced thickness, or portions with pores or filled with a particulate material to further weaken the portions of the area (s) or panel (s). There can be any suitable number of flex areas. Preferably, there are two or more. The more there are, \ Thicker can be. However, generally, the more there is, the less circumferential thread length. Preferably, the bending areas are evenly spaced or equally spaced from one another around the circumference of the lid. This allows the lid to be axially balanced in circumferential shape and provides uniform torque in relation to the rotation of the cap around the threads of, for example, the neck of a container. It is not necessary that each of the bending areas be of the same thickness.

It is not necessary that each bending area be of the same design or configuration, provided that the purpose of the invention is fulfilled. In this way, any or all of the bending areas can be of any suitable size, shape, design or configuration. For example, they may be rectangular, trapezoidal, conical, frustoconical, circular, oblong, spiral, helicoidal, or any combination thereof. Although less preferred, there may be certain applications where it may be desirable for the bending areas to span, direct c follow one or more threaded segments. As shown, preferably the flexure areas are rectangular, although they may preferably also be slightly frustoconical or tapered (to be wider at their lower ends). Preferably, the bending areas are arranged axially. The flex areas can be of any suitable height or length. Preferably the bending areas are of uniform height and extend over the entire height or length of the side wall of the lid. As explained below, one or more bending areas of the side wall may extend within a portion of, or diametrically through, the top wall of the lid. According to a main objective of the invention, the one or more flex areas can be in any proper location of the lid. For example, the one or more flex areas of the lid can be located only on the top wall of the lid or only on the top wall gasket and the side wall of the lid. S the bending areas are located in the upper wall of the lid, preferably extending up to the joint of the upper wall and more preferably towards the side wall of the lid. For example, as shown in Figures 9E-9H, the top wall 11 'may have flexure areas 14' which are preferably arranged in a star pattern in the top wall 11", and extending to the edge or flange 13. 'of the side wall 12' The entire area of the top wall can be of reduced thickness and can be considered a bending area within the scope of the invention to allow the side wall to flex radially outwards to facilitate demolding of the wall. side wall of the lid without distortion or erasure of the lid Figure 2 is a top view of the lid of figure I. Figure 2 shows that the lid 10 has an upper wall 11. Figure 3 is a bottom view of the lid of figure 1. The side wall 12 has an external surface 16 and an internal surface 18.

Figure 4 is a vertical section through a segment 20 of a thread 22. The thread is preferably a thread trapeiform but not necessarily. The thread is preferably long enough to support itself during the demolding process by ejection. Its thickness is preferably approximately 0.381 mm (0.015 inches). Figure 5 shows a segment 10 of a thread 22. Figures 6 and 7 show segments of alternating threads 20 that open the areas of flexure 14. These figures also show the outlet groove portion 24 of a segment 20 lying on the inlet groove portion 26 of a lower segment 20. Since the inlet groove and outlet groove portions are tapered radially outwardly (progressively thinner) toward the inner surface of the side wall, they do not raise an interference or demolding problem. Figures 8 and 9 are perspective views of the lid 10. Figure 9 shows that the flex areas 14 are located between the thread segments 20, and that the flex areas preferably extend towards the lower edge or ring 17 the side wall. Figures 9A to 9D show a second embodiment of the lid of the invention, generally designated as 10 '. which has flexible panels 14 'extending from the outer surface 16' of the side wall 12 'radially to the interior of the side wall 12' of the lid 10 '. The flex panels 14 'extend from the upper edge or ring 13' to the lower edge 17 'of the side wall. The bending panels are substantially parallel to the e e of the lid 10 'and are equally spaced around the circumference of the lid. Figures 9E to 9H show a third embodiment of the lid of the invention, generally designated 10". The lid 10" is similar to the lid 10 'except that the lid 10"has a plurality of flex panels that are they extend downwards to the interior and are arranged in a star or radial pattern in the upper wall 11". The flex panels 14 'are shown interrupted by a central portion 15' which is of the normal thickness of the upper panel 11. "Although in these figures the flex panels 14 'could enter the ring 13' of the side wall 12 ', no they do not join the bending panels 14 ', providing one or more panels of downward bending within the upper outer surface of the upper portion 11"as shown in Figures 9E to 9H, or upwards within of its internal surface, helps to achieve the objectives of the invention because it weakens the Tangential resistance of the side wall. The bending panels 14 'can extend one inside the other by eliminating the central portion 15. Figures 91 to 9L show a fourth embodiment of the lid of the invention, designated in general as 10 '' '. The lid 10 '' 'does not have an upper ring such that the upper panel 11' '' is directly joined to the side wall 12 '' '. In this embodiment, the flex panels 14 '' 'on the top wall 11' '' and the side wall 12 '' 'are joined to one another and form a continuous flexible panel. This flex panel arrangement allows the opposite portions of the lid 10 '' 'on each side of the flex panels to move away from each other in an articulated form from an area adjacent to the top panel 11' '', to facilitate demolding by ejecting the cap from a center of a molding tooling. Figures 9M to 90 show a fifth embodiment of the cover of the invention, here designated in general as 100. This embodiment shows that the flex panels 14 'can be advantageously employed with the continuous bending panel 14' '', the first it allows the side wall to radiate radially outwardly, and the latter allows the side wall to articulate adjacent to the top panel 11 '' ', and thereby cooperatively enabling or facilitating unmolding by ejection of cover 100 from the center of the molding tooling. Figures 9P to 9S show a sixth embodiment of the cover of the invention, generally designated 100 '. The cover 100 'has bending panels 114 that extend from an outer peripheral portion of the upper panel 111 through the seal 117 and downward towards the external surface of the upper portion of the side wall 112. This configuration of bending panels arranged circumferentially around the seal of the upper wall and the side wall create pivot points which allow the side wall to move outwards to facilitate demolding by ejection. The flex panels 114 may be of any suitable length in the top wall and the side wall. For example, they may simply be configured as a plurality of circumferentially spaced notches (not shown) formed in the seal 117 between the top panel 111 and the side wall 112. In this manner, the embodiments of Figures 9A to 9S show that the panels can be of any size, configuration and location suitable to meet the purpose of the invention, to reduce the tangential strength of the side wall to facilitate demolding by ejection of the lid.

A main concept of the invention is that the lid of the invention can easily be demoulded from the male tooling or center on which it is molded. As shown in FIGS. 10 and 11, the male mandrel 38 has alternating grooves 40 therein and in which alternating thread segments are formed. The mandrel 38 also has axial ribs 42 extending radially outwardly protruding from its outer surface. The ribs 42 form areas of flexure 14 in the lid 10. Figure 10 shows the closed tool assembly, before the injection of plastic into the mold cavity. Figure 11 shows the tool set and the mold release lid, after the mold release plate 44 has moved upwards and has hooked the lower edge of the side wall 12 of the lid. Although male or center tooling has been discussed in connection with an injection molding apparatus, it should be understood that the caps of the invention and the improved apparatus and methods may also be employed in connection with compression molding and thermoforming apparatus and methods. According to the invention, the lid can easily be demoulded from the mandrel due to its reduced total wall thickness and particularly due to the very thin bending areas. This allows the side wall to expand radially outwards and thus allow each thread leave the slit in which it is formed and that is unmoulded axially of the mandrel without finding another slit on it and in this way without significant deletion of the threads. The thread preferably has an extended axial length to allow it to be functional to provide sufficient torque to securely screw the caps to the neck of a container, even if there is some deletion of a thread segment. Those skilled in the art of de-molding by lid ejection will understand how to apply the description of the present invention to caps of different sizes, types and applications. Factors that can apply and need to be considered and balanced, include the strength of the sidewall, for example, the buckling resistance, the total diameter of the lid, the number of flex areas, their dimensions (height, thickness and width). ), and the size, thickness, and profile or shape of the cap and thread. The height and taper of the threaded side wall of the lid is also a factor, since it affects the amount of expansion of the side wall and the ease of demolding. Other interrelated factors include whether the cap has a continuous or segmented threading, and the level of the demoulding force, the thread distortion, and the desired torque retention for the application being considered.

The weakened areas, flex areas or panels are preferably the thinner areas of the lid. They are substantially less thin than the minimum thickness of the lid, excluding the thread. Preferably they are substantially thinner, preferably from 1.2 to about 4 or more times thinner than the thickness of the cap excluding the thread. The thickness of the thin bending areas, in this case panels, of the side wall, are preferably and usually the thinnest portions of the side wall. The bending areas or panels are preferably and usually thinner than the average thickness of the cross section of the side wall. With respect to the side wall 12 of the lid 10, the bending areas 14 are preferably and in fact thinner than the average thickness of the side wall measured in the non-threaded portions of the side wall. The bending areas 14 are also preferably thinner than the other thinner portions of the side wall, i.e. those portions measured from the depths of the grooves in the grooved surface of the cover to the non-threaded inner surface of the side wall. . Preferably, the bending areas are generally less thick, preferably substantially less thick than the minimum thickness of the general side wall. The objective is that the Flexion areas are designed to focus, with interconstructed weak areas that provide greater flexibility than the rest of the side wall, or sufficiently flexible, so that the side wall has a tangential strength and allows the lid to be removed from the mold with less force and Less distortion or alteration of the thread than without the areas of flexion. In the lid 10, the bending areas 14 are weaker than the corrugated portions of the lid. The bending areas 14 are desirably as thin as possible to meet the objectives of the invention, but not so thin that they tend to split or break during unmolding or the application of a torque. A bending area 14 need not be of uniform thickness. And each bending area 14 does not need to be of the same thickness as the other bending areas. The areas of flexure 14, especially when they are very thin, preferably occupy only a minor portion, i.e. less than about 50%, of the circumference, periphery or width of the cap. Otherwise, the cap may be very weak and / or may not have enough thread to sufficiently engage the commuting thread (s), for example, on the neck of a container, or sufficient tangential resistance to hold the lid on the container or seal it properly. In modalities Preferred threads employing segmented threads, the bending areas 14 are preferably narrower than the width or degree of arching of the shortest of the thread segments. Although it is generally true that the wider the bending area of the panel, the greater the flexibility of the side wall, it is considered to be within the scope of the invention to provide many narrow axial bending panels that would not unduly limit the number of thread segments or unduly weaken the side wall. With wide flex areas or panels, the thicker panels between the flex areas have more freedom to expand, flex, or pivot out independently or in combination and prevent the erasure or distortion of single or multiple threads. Desirably, the side wall should be capable of expanding, or pivoting, from the weakest point near the top wall of the lid, a distance that is at least about one-half the radial thickness of the thread on the inner surface of the wall. the lid. Preferably, the side wall is capable of expanding a distance that is the greater part, of the total or greater than the total radial thickness of the thread, threads or thread segments. The flexure areas preferably extend from the inner surface of the lid radially outwardly towards the outer surface of the lid. However, it is contemplated within the scope of the present invention that one or more bending areas may extend from the outer surface radially inward toward the inner surface of the lid. A combination of these types of flex areas can also be employed. The caps of the invention are very suitable for containers for products that are packaged with a low internal pressure. The lids are also very suitable for containers and packaging applications with limited life. It should be understood that the present closure or cover includes any cover for the opening of an article or container. It is contemplated that a closure or cover includes a closure with a base and a top or "flip top", secured to the lid by means of a support or other hinges or strips. The closures or caps of the invention are not limited by the means by which the lid is secured or held on the article or container. Therefore, the closures or caps of the invention may have any suitable means for securing the closures or caps to the neck of a container or to a base of a lid which in turn is secured to a container. The side wall of the cover may not be threaded and may include a radially extending inwardly extending member, for example, a flange for engaging or frictionally fastening on or holding a cooperative portion of a neck or other portion of an article or container. The lid of the invention is preferably threaded on the inner surface of the side wall. Any suitable type of threading can be used. The thread profile can be round, V-shaped or angular, trapeiform, or modified trapeiform or a combination of these or other forms. As stated above, a preferably trapeiform thread, more preferably modified trapeziform, may be employed. The thread engaging surfaces of the trapezoidal thread are preferably tapered at an angle of about 15 to about 25 degrees relative to the inner surface of the side wall of the cap. This thread is desirable because it provides greater torque resistance than a V-shaped or round thread. Although the latter is easier to demold from a center, it provides less torque resistance and may not provide sufficient seals. The modified trapeiform thread can be used as an advantage although it can easily be demoulded from a center with minimal distortion or erasure when used in a lid of the invention. Although the thread employed in the lid of the invention can be continuous, with or without changing the depth or profile, preferably the thread is alternating or segmented, with or without changing the depth or profile. The thread segments may be distributed uniformly or non-uniformly around the circumference of the side wall of the lid. The bending areas 14 preferably extend axially between the threaded segments. The pitch of the thread or thread segments is rather coarse rather than fine, and the preferred step for the modified trapeiform segmented thread of the lid 10 is approximately 12 turns per inch. It is generally accepted to provide at least one turn of rope hook for uniform, balanced torque and for uniform axial pulling force. For the embodiment with the segmented thread shown in the drawings, the thread segments preferably extend circumferentially around the side wall for a total of two full turns, but about half the length of the thread has been removed. The segmented thread is extended over a distance of two turns of thread (720 degrees), with a net result similar to a full turn of continuous thread. Preferably, no portion of a total thread segment overlaps axially (lies or underlies) with another portion of another total thread segment. By total thread segment is meant the portion of a segment that is of a total axial height and radial thickness. So, with the segmented thread 22 of the lid 10 no portion of a segment 20 of the thread 22, other than that of a tapered portion of the input groove or exit groove thereof, axially overlaps a total thread segment lying or underlying . In lid 10, the total thread thickness is approximately 0.381 mm (0.015 inches) measured from the inner surface of the side wall. The total thread height of a segment is approximately 1,067 mm (0.042 inches). Any overlap of the threaded segments may be tolerated, at the expense of further thread erasure or distortion unless the side wall of the lid is tilted at an angle to the vertical to facilitate unmolding of the center cover, and / or a more tapered center is used. The side wall of the lid 10 of the invention can generally be at an angle of from about 0 to about 4 or 5 degrees, preferably about 3 degrees, and more preferably about 2.5 degrees. The greater the angle, the easier it will be to unmold the lid of a center, but the torque resistance is smaller in relation to the matching thread of the container. A very steep taper reduces torque and retention of the cap and seal. It can provide any suitable cap with weakened areas, for example, flex areas, according to the invention. The lid can have a wall, side wall or annular or encircling ring with a vertical threaded, conical or tapered internal surface. The outer shape of the lid can be of any suitable shape, for example, round, oval or square. The lid can be a "flip top" dispenser item or another single or multi component. Its wall thickness can be uniform or non-uniform. For example, it may have grooves or ribbed or with a pattern. The cap may include or may be used in combination with child-proof or tamper evident characteristics. The weakened areas, for example, the flex areas can be or are part of a feature or features of this type. The lid can be formed of any material usable for the formation of lids. Examples of such materials include polymers and copolymers of propylene and ethylene, including high, medium, low, very low density and high density polyethylenes, polypropylenes, ethylene-propylene copolymers, filled or unfilled, and polyesters, for example, polyethylene terephthalates. Preferably, the lid comprises one or more thermoplastic materials. The covers can be single layer or multiple layers, with barrier or without barrier. The material (s) of the lid can include polymers made from simple site catalysis systems, for example, metallocene catalysts. The appropriate materials of this type for the The formation of lids is described in the application and US patent with serial No. 09/144/713, presented in September. From 1998, whose full description is incorporated here as a reference. The apparatus of the invention can be any suitable apparatus for molding a lid. The apparatus includes a female tooling and a center operable therein to form a mold cavity for forming a cap Female tooling or the center can be formed or modified to form the flexible areas on the inside, outside or both surfaces of the lid. Preferably, the center has an external surface with a plurality of slit segments formed radially within the surface for formation in the center, a lid with an l-> 0. side wall or annular wall with an internal surface having a segmented thread that extends radially inward The segments of the thread are formed in the segments of the grooves. The slit segments of the center preferably include a first segment of a main groove having an inlet groove portion that gradually deepens, tapers or tilts, and an end groove segment having an outlet groove portion that it gradually becomes thin, tapers or tilts. Preferably, no ^ total portion of a slit segment lies or underlies axially in another portion of another slit segment. The total portion of a thread segment is that portion of a thread segment that is not a portion of the input groove or output groove of the thread segment. The center of the apparatus of the invention may be a demolding center, a collapsible center, a screwable center or a combination thereof. The outer surface of the center does not need to be tapered but is preferably tapered with a slightly decreasing diameter toward the end of the center forming the upper portion of the lid, to facilitate removal of the center cap. The external surface of the center of the invention can be generally tapered at an angle of about 0 to about 4 or 5 degrees, preferably 3 degrees, and more preferably 2.5 degrees. If bending panels are provided on the outer surface of the lid, the female tooling is provided with ribs or buttons, etc. which extend radially outwards, as is appropriate for the formation of type, shape, etc. desired bending panels on the outer surface of the lid. Preferably, the bending panels extend axially along the side wall circumferentially between the threaded segments. The present request relates to the provisional application of the United States entitled "Recipient Improved and Method and Apparatus for the Formation of the Container. "This application is presented on the same date as the present application and is assigned to the same beneficiary.The demolding by ejection of a threaded closure reduces the molding cycle compared to unscrewing. Thin "flex" areas allow the cap to distort during ejection by ejection, a modified trapeiform thread is preferred because it provides greater torque integrity compared to the "rounded" thread, the discontinuous thread is molded into a wall tapered and alternating to ensure that the next step of the thread does not erase the threaded wall during the demolding by ejection.The discontinuous thread is alternating, but will still provide a balanced torque and a uniform axial pulling force when applied to a continuous thread , coincident of a container.The lid is designed to be demold by ejection. Typical ulsion employ rounded continuous threads on a cone. The closure of the invention is designed with a modified trefoil thread to provide a better retention torque when applied to the container. The modified trapeiform thread is segmented on a preferably conical wall in a pattern that does not allow one thread to be directly above another. This pattern will allow the demolding by ejection with minimal erasure / distortion of the thread. The wall of the closure will flex outwardly during ejection, preferably due to thin symmetrical segments in the wall preferably parallel to the axis of the lid. These segments are designed to flex during ejection (hot polypropylene), but recover when cooled. The continuous wall of the cap will provide sufficient tangential strength to maintain the required thread engagement, torque and seal integrity when applied to a container. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (31)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A plastic cover, characterized in that it comprises: an upper portion, an annular side wall that depends on the upper portion and has an internal surface, means for securing the cap to the neck? a container, and substantially weakened areas provided in the cap to allow the side wall to expand radially circumferentially outwardly when the inner surface of the side wall is subjected to a radially directed force toward outside. A lid comprising a thermoplastic material and having an internal surface and an external surface, characterized in that it comprises: an upper portion, an annular side wall that depends on the upper portion, the side wall has an internal surface having a thread that extends radially inward, and a plurality of bending areas that are less thick than the average thickness of the lid, and which increase the capacity of the side wall to expand radially outwardly such that the lid can be demolded by ejection from a mold center having a external surface with a thread forming groove in it, with a reduced erasure or distortion of the lateral wall threading due to the center slit in comparison if the lid had no weak areas. 3. The lid according to claim 2, characterized in that the flex areas are the thinner areas of the lid. The lid according to claim 2, characterized in that the bending areas are substantially less thick than the minimum thickness of the rest of the lid excluding the thread. The cover according to claim 2, characterized in that the bending areas are approximately 1.2 to approximately 4 or more times thinner than the thickness of the cover excluding the thread. The lid according to claim 2, characterized in that the flexing areas are located in the upper portion of the lid. The lid according to claim 2, characterized in that the flexing areas are located in the side wall. The lid according to claim 2, characterized in that there is a seal between the upper portion and the side wall of the lid, and the flexing areas are located in the joint. The lid according to claim 1, characterized in that the weak areas are bending panels. The lid according to claim 2, characterized in that the flex areas are flex panels. The lid according to claim 10, characterized in that the flex panels are formed on the inner surface of the side wall. The lid according to claim 10, characterized in that the flex panels are formed on the external surface of the side wall. The lid according to claim 10, characterized in that the flex panels are formed in the upper portion of the lid. The lid according to claim 10, characterized in that the upper portion of the lid has an external surface and an internal surface, and the flex panels are formed on the external surface of the upper portion of the lid. 15. The lid according to claim 1C, characterized in that the upper portion of the lid has an outer surface and an inner surface, and the flex panels are formed on the inner surface of the upper portion of the lid. The lid according to claim 2, characterized in that the side wall includes a lower ring, the bending areas comprise a plurality of circumferentially spaced panels and each of the bending panels is continuous from the upper portion of the lid to the lower ring of the lid 17. The lid according to claim 2, characterized in that the bending areas are narrow and elongated flexing panels, which are formed at the side wall and extend in a substantially continuous direction parallel to the longitudinal axis of the lid. The lid according to claim 17, characterized in that the widths of the bending panels are inclined inwardly as they extend towards the upper portion of the lid. 19. The lid according to claim 2, characterized in that the thread is formed of segments that are alternately circumferentially one with the other. 20. The cap according to claim 19, characterized in that no thread segment lies or It underlies another thread segment. The cover according to claim 19, characterized in that no thread segment directly underlies another thread segment. The lid according to claim 19, characterized in that the threaded segments have full portions and portions of the inlet groove and exit groove, and no full portion of a segment overlaps axially with a portion that lies or underlies the portion. Complete of a threaded segment. 23. The lid according to claim 19, characterized in that the flex panels are located between the threaded segments. 24. The lid according to claim 19, characterized in that the bending areas are equally spaced from one another around the lid. The lid according to claim 10, characterized in that the flex panels are formed in the side wall and are thinner than the average vertical cross sectional thickness of the side wall. The lid according to claim 10, characterized in that the flex panels are thinner than the average thickness of the vertical cross section of the side wall measured in the unthreaded portions of the side wall. 27. The lid according to claim 10, characterized in that the bending areas are substantially thicker than the average thickness of the lid. 28. A lid, characterized in that it comprises: an upper portion, and a side wall depending on the upper portion, the side wall has a side wall with an internal surface with a thread extending radially inward, to secure the cover to the threaded neck of a container, the thread of the lid comprises complete segments that are spaced circumferentially from one another such that no portion of a complete segment overlaps axially with a portion of another complete segment. 29. The lid according to claim 28, characterized in that the side wall has portions of a first thickness, and has bending areas of a second thickness that are thinner than the first portions, to allow the side wall to be stretched principally. in the areas of flexion and thus further increase the ability of the lateral wall to expand radially outwards when the side wall is subjected to a force internally directed radially outward in comparison if the same force were applied to said side wall without the areas of flexion. 30. The lid according to claim 29, characterized in that the flexing areas include bending panels. 31. A method of molding a removable plastic lid by ejection, characterized in that it comprises: molding a lid in a tool set having a mold cavity formed by a female tool for the formation of the outer surface of the lid and by means of a center for the formation of the internal surface of the lid, in such a way that the lid will have an external surface, an internal surface, an upper wall, and a dependent side wall having a thread and which is in communication with the upper wall, and the provision of limbs extending radially outwardly on the eternal surface of the center to form weakened areas that extend radially inwardly on the inner surface of the lid, the members extend radially outwardly enough in such a way that the weakened areas are thinner than the average thickness of the lid, to allow the side wall to expand radially outward and out of this way to allow the lid to be demolded by ejecting the tooling from the mold with a reduced erasure of the thread.