MX2008005559A - Method and machine for compression molding closure shells - Google Patents

Abstract

A compression molding machine, for compression molding a closure shell (128) having a base wall with an opening, includes a male mold section (54) and a female mold section (56) having associated surfaces that oppose each other to form a cavity for compression molding the base wall of the closure shell . An annular bead ( 114) on one of these surfaces cooperates with the opposing other surface to compression mold a disk connected to the base wall by a thin frangible web. The disk and the shell are stripped separately from the mold so that the shell emerges from the machine with the opening formed in the shell base wall by removal of the disk within the machine.

Description

METHOD AND MACHINE FOR MOLDING BY COMPRESSION OF CLOSURE COVERS Field of the Invention The present disclosure is directed to a method and a machine for compression molding of closure covers having an opening in the cover base wall.

BACKGROUND OF THE INVENTION Machines for compression molding of closure covers typically include a turret or carousel that rotates about a vertical axis. A plurality of molds around the periphery of the carousel includes male and female mold sections which are aligned along vertical axes parallel to the axis of rotation. The cams drive one or both of the mold sections of each pair between a separate open spaced position, in which a molded part is removed from the male mold section and a load of plastic material is placed in the female mold section, and a closed position in which the male and female mold sections are put together to compressionly mold the load to form the cover. US patents illustrating such machines for compression molding of plastic closure covers include 5,670,100, 5,989,007, 6,074,583 and 6,478,568. REF. : 192755 There are applications in which it is desirable to provide an opening in the base wall of the closure cover. For example, US 2004 / 0108294A1 discloses a plastic closure that includes a cover having a base wall with a central opening and a border with at least one internal thread or flange to secure the closure to a container termination. A plastic disc is retained within the cover parallel to but spaced from the closing base wall. One or more spacer elements axially extended in the disk engage the lower surface of the closing base wall and space the disk of the base wall of the cover. A resilient liner is placed on the underside of the disc for sealing engagement with the container termination. After the application of the closure to a container termination, the fluid can be directed through the opening in the closing base wall, between the disc and the lower surface of the base wall, beyond the spacer elements, and then between the closing edge and the container termination for jetting the debris or the like between the closing cover and the disk and termination. Another example could be a closure cover having an opening for receiving a distribution valve or the like. In the compression molding of closure covers of this type, the cover can be manufactured with a disc in the base wall, which is removed in a post-molding operation to provide the desired opening in the base wall of the cover. U.S. Patent 6,673,295 discloses a closure cover and a manufacturing method of this type. A general object of the present disclosure, in accordance with one aspect of the disclosure, is to provide a machine and method for compression molding a closure cover having a base wall with an opening, in which the disc is removed from the closing cover inside the compression mold, eliminating the need for a post-molding operation to remove the disc from the cover.

Brief Description of the Invention The present description involves a number of aspects or inventions, which may be implemented separately or in combination with each other. A compression molding machine according to a first aspect of the present disclosure, for compression molding a closure cover having a base wall with an opening, includes a male mold section and a female mold section having associated surfaces. which oppose each other to form a cavity for compression molding the base wall of the closure cover. An annular flange on one of these surfaces cooperates with the other opposing surface for compression molding a disc connected to the base wall by a thin frangible mesh. The disc and cover are removed separately from the mold so that the cover emerges from the machine with the opening formed in the cover base wall by removing the disc inside the machine. A continuous motion compression molding machine, in accordance with a currently preferred embodiment of another aspect of the disclosure, includes a wheel mounted for rotation about an axis and a plurality of angularly spaced molds positioned around the wheel. Each of the molds includes a male mold section and a female mold section aligned with each other. The mold sections have associated surfaces opposing each other to form a cavity for compression molding the cover base wall. Each of the male mold sections includes a mold core having a front face and an annular ridge on the front face of the core, a spacer sleeve surrounding the core and a spacer punch within the core. A cam is positioned adjacent to the wheel to couple the molds and move at least one of the mold sections of each mold in sequence between an open position to separate the molded covers from the cores and place the mold loads in the molds, and a closed position to compression mold the mold loads. The male and female mold sections cooperate to compression-mold a disk into the flange on the front face of the core, which is connected to the cover base wall by a thin frangible mesh. The spacer sleeve and the spacer punch are movable separately from each other with respect to the core in each male mold section to separate the cover and the disc separately from the core, so that the cover emerges from the machine with the base wall opening formed by removal of the disk. The wheel may comprise a horizontal wheel as in a carousel-type compression molding machine or a vertical wheel that is rotatable about a horizontal axis. A machine for molding a closure cover having a base wall with an opening, in accordance with a further aspect of the disclosure, includes a male mold section and a female mold section having associated surfaces that oppose each other to form a cavity for molding the base wall of the closing cover. The male mold section includes a core having an end that forms at least a portion of the surface in the male mold section, and a flange at the surface forming end for cooperating with the opposite surface of the female mold section for molding a disc frangibly connected to the base cover wall by a thin frangible mesh. The disc and cover are separately removable from the mold core so that the cover emerges from the machine with the disc removed and the opening formed in the base wall of the cover. A method of compression molding a closure cover having a base wall with an opening, in accordance with still another aspect of the disclosure, includes compression molding a closure in a mold such that a disc is connected by a mesh frangible to the base wall of the closure, and separating the closure cover from the compression mold separately from the disc so that there is an opening in the base wall where the disc was molded. The disk can be separated from the mold either prior to or subsequent to the separation of the mold cover.

Brief Description of the Figures The description, together with additional objects, features, advantages and aspects thereof, will be better understood from the following description, the appended claims and the accompanying figures, in which: Figure 1 is a view in front elevation of a compression molding machine according to one embodiment of the present disclosure; Figure 2 is a side elevational view of the compression molding machine illustrated in Figure 1; Figures 3A-3D together form a sectional view taken substantially along line 3-3 in Figure 2; Figure 4 is an elongation of a portion of Figure 3B; Figure 5 is an elongation of a portion of Figure 4; Figures 6-8 are fragmentary sectional views illustrating another embodiment of the present disclosure; Figure 9 is a fragmentary sectional view of a compression mold according to still another embodiment of the description; Figure 10 is a fragmentary sectional view of a further embodiment of the present disclosure; and Figure 11 is a fragmentary sectional view of another embodiment of the present disclosure.

Detailed Description of the Invention The description of U.S. 2004 / 0108294A1 noted above is incorporated herein by reference. Figures 1-2 illustrate a machine 20 for compression molding plastic closure covers in accordance with one embodiment of the disclosure. Machine includes a wheel 22 mounted on an axle 24 between spaced supports 26, 28. The axle 24 is coupled by a pulley 30, a band 32 (Figure 2) and a gearbox 34 to a motor 36 for rotating the shaft 24 and wheel 22 around a horizontal axis. The wheel 22 includes a bushing (which may be part of the shaft 24) and a support 39 radially extended from the bushing. The support 39 may comprise a solid disc or the like, or more preferably a plurality of angularly spaced radially spaced support spokes 38. Each support radius 38 is hollow at its outer end, as best seen in Figures 3A-3D. A rod 40 is slidably supported, such as by sleeve bearings 42, within the hollow outer end of each spoke 38. A cross bar 50 engages the outer end of each rod 40 so that the combination of rod 40 and rod 50 is generally in the form of T as seen from the tangential direction in Figure 3B. A plurality of radially spaced external supports 44, 46 are provided on each axial side of each radius 38. The radially internal supports 44 in the series of spokes preferably form circumferentially continuous support rings, as best seen in Figure 2. The supports radially outer 46 are preferably circumferentially spaced from each other. A plurality of angularly spaced molds 52 are placed around the periphery of the wheel 22, preferably on both sides of the wheel. Each mold 52 is placed between the supports 44, 46 on an associated radius 38 and one end of the cross bar 50 on the rod 40. All the molds 52 are preferably identical. To the extent described so far, the machine 20 is similar to that described in the co-pending US application (Document 18565) entitled "Compression Molding Machine", the description of which is incorporated herein by reference. Each mold 52 preferably includes a first radially internal mold section or segment 54 and a second mold section or segment 56 in radially external alignment with the associated first mold section 54. In the preferred embodiments of the disclosure, to the extent encompassed in a vertical wheel machine, the first radially internal mold section 54 is a male mold section and the second radially external mold section 56 is a female mold section, although these mold sections may be inverted in accordance with the broader principles of the description. The male mold section 54 includes a mold core 58 (figures 3b, 4 and 5) having a core tip 60 mounted on the end of a core sleeve 62. A spacer punch 64 is slidably carried within an opening 65 at the end of the core tip 60, preferably coaxially with the tip of core and the core sleeve. The punch 64 has a hollow rod 66 (FIG. 5) extending from a head 67 in a core cooling insert 68 (FIGS. 3B and 4) mounted inside the core sleeve 62. An air tube 70 extends from the insert coolant 68 through a core shaft 71 (Figures 3B and 3C) mounted on a cooling insert 68 inside the core sleeve 62, and then to a distributor 72 carried by the core shaft 71. The distributor 72 in this embodiment has an inlet fitting 74 for feeding air under pressure through the tube 70 to a passage 76 in the separation punch 64. The passage 76 (figure 5) is generally T-shaped, has supports 78 at the end of the punch 64 for feeding the air through the annular opening 79 between the punch head 67 and the end of the core tip 60. A flange 80 (Figures 3B and 4) extends from the stem 66 of the punch 64 laterally through a notch 82. (figure 4) in the core sleeve 62 in a notch 84 in a spacer sleeve 86 slidably surrounding the core 58. The notch 84 in the spacer sleeve 86 is preferably in the form of an annular internal cavity that extends completely around the interior of the spacer sleeve. A collar 88 engages an external notch 89 in the spacer sleeve 86. At least one rod 90 slidably extends from the collar 88 through an aperture in the cross bar 50. A collar 92 (FIG. 3A) is adjustably mounted in the rod 90 for engagement by the cross bar 50 when the female mold section 56 is withdrawn radially externally to open the mold, as will be described. One or more springs 93 (Figures 3B and 4) are captured in compression between the flange 80 and the tip end of the core 60 to bias the spacer plug 64 to a closed position, in which the cap head 67 rests on a inner projection 91 (figure 5) of opening 65. Distributor 72 also carries coolant inlet and outlet fittings for circulating coolant through mold core 58, as described in detail in the copending application referenced above. A cam follower roller 94 (Figures 1, 2 and 3A) is rotatably mounted on a support 95 extending radially externally of the cross bar 50. The support 95 preferably is offset from the axis of the rod 40 in which the crossbar 50 is mounted so that the cam follower roller 94 aligns with the axis of the rod 40. Each cam follower roller 94 on each transverse bar 50 in the exemplary embodiment illustrated accordingly is associated with two molds 52 located on opposite sides. of the wheel 22. A cam 96 is preferably positioned along the lower arc of the periphery of the wheel 22, as best seen in Figure 2, to engage the cam followers 94 in sequence when the wheel 22 rotates around of its horizontal axis. During the clockwise rotation of the wheel 22, in the orientation of Figure 2, the follower roll 94 of each mold 52 in sequence is engaged and captured by the cam 96 to push the female mold sections 56 externally and downwardly away from the male mold sections 54. When each mold in turn is completely open, the closures are removed from the mold cavities by an appropriate part removal mechanism 98 (Figure 2). A new mold load of plastic material is then placed in each mold by a suitable positioning apparatus 100. When the wheel 22 continues rotation, the female mold segments 56 in sequence move up and internally to their closed positions with respect to the male mold segments by the clockwise end of the cam 96, again in the orientation of Figure 2. The mechanism for removing the molded article 98 and the apparatus for placing the mold load 100 can be of any suitable type. Hydraulic, pneumatic or electric actuators may be used at each radius 38, instead of the cam 96, to move the female mold sections radially internally and externally. Each female mold section 56 includes a cavity forming insert 102 (Figures 4 and 5) in a mounting block 104 carried by the cross bar 50. The coolant flow of the cross bar 50 a and the block 104 and insert 102 preferably is as described in the copending application referenced above, a mold pin 106 is mounted on the block 104 and is diverted through an opening 07 in the insert 102, towards the male mold section 54, by a spring 108 captured in compression between the pin 106 and the opposite surface of the cross bar 50. The pin 106 has a front face 110 which is preferably substantially planar. The opposite front face 112 of the core tip 60 has an annular rim 114. The rim 114 has an annular internal biased cut best seen in Figure 5 and surrounds a plate 116 that is raised with respect to the front face 112 of the tip of core 60. Flange 114 is aligned and preferably is coaxial with core pin 106 in female mold section 56. Pin 106 is movable to accommodate small variations in mold loading pellets. A sparger 107 (FIGS. 3B, 4 and 6) provides cooling to the pin 106. In operation, with the mold sections 54, 56 spaced apart from each other, a mold load of suitable plastic material is placed inside the mold, such as being placed inside the mold cavity insert 102 in the embodiment of Figures 3A-5. When the mold segments are then closed, the mold load is compression molded between the male mold section 54 and the female mold section 56. The flange 114 compresses the plastic material against the surface 110 of the pin 106 to form an annular mesh thin frangible 117 (Figure 5) between the disk 118 formed against the plate 116 and the base wall 119 of the closure. The base wall 119 is annular and integrally connected to the disk 118 by the frangible mesh 117. The base wall 119 (as well as the mesh 117 and disk 118) is compression molded between the opposing surfaces of the pin 106 and insert 102 in the section of female mold 56, and core tip 60, core sleeve 62 and spacer punch 64 in male mold section 54. Plate 116 is preferably offset from the surrounding annular surface 112 of core tip 60 to reduce the amount of material on the disk 118. The external surface of the punch head 67 preferably is coplanar with the plate 116 in the closed position of the mold. When the mold sections are then opened relative to each other, such as by external movement of the female mold section 56 in the illustrated embodiment of the description, the coupling of the cross bar 50 with the collar 92 on the rod 90 (FIG. 3A) pushes the collar 88 and spacer sleeve 86, which engages with the axial edge of the edge 121 (FIG. 5) of the molded closure cover. The spacer sleeve 86 therefore separates the closure cover (128 in FIG. 7) from the mold core 58. Meanwhile, the disc 118 in the center of the closure cover is held within the annular flange 114, so that the frangible mesh 117 that connects the disc to the cover breaks, leaving the disc in the mold core while the cover separates from the mold core. The continuous movement of the separate sleeve 86 in the long run puts the end of the notch 84 in engagement with the flange 80, so that additional movement of the spacer sleeve also moves the flange 80 and core punch 66 with respect to the core tip. 60 and core sleeve 62. This movement of the punch 66 separates the disc 118 within the rim 114 for recycling or removal. The loose movement between the spacer sleeve 60 and spacer punch 64, performed in this embodiment by flange 80 and notch 84, ensures that the closure cover is removed from the mold core prior to the separation of the disk from the mold core. The cover consequently emerges from the mold with the central opening formed in the cover base wall 119. A spacer punch 64 moves externally in this embodiment, air under pressure preferably being fed through the accessory 74 and distributor 72 (FIG. 3C), air tube 70 (figures 3B, 3C and 4), passages 76, 78 in the punch 64 (figures 4 and 5) and opening 79 (figure 5) to assist separation of the disk 118 from inside the rim 114.

Figures 6-8, 9, 10 and 11 illustrate respective additional embodiments of the present disclosure. In each of these figures, the components that are the same or similar to those illustrated in figures 1-5 are indicated by correspondingly identical reference numbers. Figures 6-8 illustrate a male mold section 122 and a female mold section 124. A difference between the mold 120 in Figures 6-8 and the mold 52 in Figures 3A-5 is the absence of an air tube. 70 (Figures 3B-3C and 4) to assist separation of the disk 118 from the end of the core tip 60. Furthermore, in this embodiment, the separator sleeve 86 is mounted on a support 126 which is held stationary while the mold core 58 is retracted to separate the closure cover 128 (FIG. 7). One or more springs 129 bias separator sleeve 86 to close the mold cavity (Similar springs 129 are shown in Figure 3B). Loose movement between the flange 80 and the sleeve 86 due to the notch 84 activates the separating punch 64 only after the closure cover has been completely separated (Figure 8E). Figure 9 illustrates a mold 130 that is similar to the mold 120 of Figures 5-9, but additionally includes an air tube 70 coupled to the accessory 74 in the distributor block 72 for feeding compressed air through the separator punch 64 to assist the separation of the disc from the core tip, as previously described. Figure 10 illustrates a mold 132 that is similar to the mold 52 in Figures 3A-5, except that the spacer sleeve 86 and the spacer punch 64 are driven independently from each other. That is, the separator sleeve 86 is operatively coupled by the collar 88, rod 90 and collar 92 to the cross bar 50 as in the previous embodiment. However, in the embodiment of Figure 10 the flange 80 does not engage a notch in the spacer sleeve 86 in the previous embodiments, but rather is operatively coupled by a rod 134 and a collar 136 to the cross bar 50. collars 92, 136 are preferably independently adjustably positioned on the respective rods 90, 134 to cause the operation of spacer sleeve 86 and spacer punch 64 to wobble. Accordingly, spacer sleeve 86 can be operated either prior to or subsequent to the spacer punch. 64 separates the closure cover from the mold core either prior to or subsequent to the separation of the disk from the mold core. Figure 11 illustrates a modification of the figure , in which the collar 88 coupled to the rod 90 is placed closer to the tip of the spacer sleeve 86, and in which a spiral spring 138 is captured in compression surrounding the rod 134 between the flange 80 and the cross bar 50 to divert the separating punch 64 to the sitting position. Accordingly, a method and machine have been described for compression molding of plastic closures including an opening in the base wall of the closure cover, which completely satisfy all objects and purposes previously described. The subject has been described in conjunction with various currently preferred embodiments, and a number of additional modifications and variations have been described. Other modifications and variations will readily suggest themselves to persons of ordinary skill in the art in view of the foregoing description. For example, although mounting the molds on a vertical wheel rotatable about a horizontal axis is currently preferred, the invention may be easily implemented on a horizontal wheel or carousel-like machine that rotates about a vertical axis, and on which the Molds are aligned along the axes parallel to the axis of rotation. Likewise, although the subject has been described in conjunction with the operation of the spacer sleeve and spacer punch by movement of the opposite mold section, it will be recognized that the spacer sleeve and spacer punch can easily be operated by one or more cams placed adjacent to the mold. wheel to open and close the mold sections and operate the separator and punch sleeve as a function of rotation of the wheel around either a vertical or horizontal axis. The use of an internal annular cavity for the notch 84 in the spacer sleeve 86 also allows rotation of the spacer sleeve with respect to the core to unscrew the core seal, as illustrated for example in U.S. Patent 6,706,231. The present invention is intended to encompass these and all other alternatives and modifications when they fall within the spirit and broad scope of the appended claims. 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 (20)

1. CLAIMS Having described the invention as above it is claimed as property contained in the following claims: 1. Compression molding machine of a closure cover having a base wall with an opening, which includes: a section of male mold and a section of female mold, the male and female mold sections have associated surfaces opposing each other to form a cavity for compression molding the base wall, an annular flange in one, of the surfaces to cooperate with the other opposing surface to mold by compressing a disk connected to the base wall by a thin frangible mesh, and means for separately removing the disk and the mold cover so that the cover emerges from the machine with the opening formed in the base wall, characterized in that the mold section male includes a mold core, a spacer sleeve that surrounds the core to separate the core shell, a separating punch den of the core to separate the disk from the core, and means for moving the separating sleeve and separating punch separately from each other with respect to the core.
2. 2. Machine according to claim 1, characterized in that the means includes a connection of loose movement between the separating sleeve and the separating punch.
3. Machine according to claim 2, characterized in that the connection of loose movement is such that the movement of the separating sleeve on the core separates the closing cover of the core before moving the punch to separate the disk from the core.
4. Machine according to claim 3, characterized in that the loose movement connection includes a notch in the spacer sleeve and a flange extending from the notch through the core to the punch, the notch being such to allow the movement of the sleeve separator on the core to separate the core cover before coupling the flange to move the punch into the core to separate the core disk.
5. Machine according to claim 1, characterized in that the means moves the separate sleeve and the separating punch independently of one another with respect to the core.
6. Machine according to claim 5, characterized in that at least one of the male and female mold sections is movable with respect to the other between an open position spaced apart from each other to remove the molded closure cover and place a load of mold in the mold, and a closed position to compression mold the cover and disc.
7. Machine according to claim 6, characterized in that the means are such that the separating sleeve moves the separating punch beforehand and the cover separates from the pre-disk mold.
8. 8. Machine according to claim 6, characterized in that the means are such that the separating punch moves the separating sleeve beforehand and the disk separates from the mold core prior to the cover.
9. Machine according to claim 6, characterized in that the means operatively couple the spacer sleeve and the spacer punch to the female mold section so that the movement of at least one section of the mold moves the spacer sleeve and the spacer punch in sequence.
10. 10. Machine according to claim 1, characterized in that the annular rim is placed in the mold core.
11. 11. Machine according to claim 10, characterized in that the annular rim includes an internal annular biased cut to retain the disc in the core pending the movement of the separating punch.
12. 12. Machine according to claim 10, characterized in that the female mold section includes a mold pin biased towards the mold core and has a surface opposite the flange in the mold core.
13. 13. Machine according to claim 1, characterized in that the mold core includes a passage for feeding air under pressure through the core and the separating punch for air assistance in the separation of the disk from the mold core.
14. Machine according to claim 1, characterized in that it includes a plurality of male and female mold sections in angularly spaced radially opposed s about a wheel mounted for rotation about an axis.
15. 15. Machine in accordance with the claim 14, characterized in that the shaft is a horizontal axis and the female mold section is mounted radially externally of the male mold section in each pair around the wheel.
16. 16. Machine according to claim 14, characterized in that it includes a cam placed adjacent to the wheel to couple the molds in sequence during the movement of the wheel to move at least one of the mold sections with respect to the other between the positions open and closed.
17. 17. Machine according to any preceding claim, characterized in that it includes: a wheel mounted for rotation about an axis and a plurality of angularly spaced molds placed around the wheel, each of the molds includes a section of male mold and a section of female mold aligned with each other, each of the male mold sections includes a mold core having a front face and an annular rim on the front face, and a cam positioned adjacent to the wheel for coupling the molds and moving at least one of the mold sections of each mold in sequence between an open position for separating the mold covers from the cores and placing mold loads in the molds, and a closed position for compression molding the mold loads, the mold sections male and female cooperate to compression mold a disc into the flange connected to the base cover wall by a thin frangible mesh.
18. 18. Machine according to claim 17, characterized in that the wheel is mounted for rotation about a horizontal axis.
19. Machine according to claim 18, characterized in that the female mold section is mounted radially externally of the male mold section in each mold.
20. 20. Machine according to any preceding claim, characterized in that it includes means for feeding air through the mold core and through the separating punch to assist in the separation of the disk from the mold core.