Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/17—Component parts, details or accessories; Auxiliary operations
  • B29C45/40—Removing or ejecting moulded articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/17—Component parts, details or accessories; Auxiliary operations
  • B29C45/26—Moulds
  • B29C45/33—Moulds having transversely, e.g. radially, movable mould parts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/17—Component parts, details or accessories; Auxiliary operations
  • B29C45/40—Removing or ejecting moulded articles
  • B29C45/43—Removing or ejecting moulded articles using fluid under pressure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2031/00—Other particular articles
  • B29L2031/56—Stoppers or lids for bottles, jars, or the like, e.g. closures
  • B29L2031/565—Stoppers or lids for bottles, jars, or the like, e.g. closures for containers

Definitions

• the present invention is directed generally to staged, sequentially separated injection molds and particularly to molds for forming container spouts having an integral panel sealing the spout and an integral pull ring to facilitate opening the spout by removal of the panel.
• Certain types of containers such as cartons and the like that have a gable- shaped top, employ separately molded plastic spouts with threaded closures.
• Such cartons will be recognized as those containers in which quarts, liters, and half- gallons of milk or juice are packaged.
• the spouts are injection molded to include a removable integral panel sealing the spout at the time of initial purchase by the consumer. Examples of such an injection molded spout are found in U.S. Patents 5,133,486; 5,735,426; 5,915,574; 5,957,312 and 6,179,147.
• the integral panel is view as a tamper-resistant feature of the closure system that is desired by the public to ensure the safety of the product within the container.
• the integral panel is joined to the spout by a frangible line, and an integral pull ring is provided to facilitate opening of the spout through removal of the integral panel by tearing the frangible line surrounding the panel.
• the spout includes a threaded exterior surface and a threaded closure to permit re-closing of the container after partial consumption of the contents.
• a steel or other metallic mold of the item to be molded is first made.
• the mold contains a mold cavity configured to reflect the part to be molded.
• the mold is periodically openable, or separable, so that the molded part can be removed from the mold cavity.
• a plastic material such as polypropylene, polystyrene or the like, is injected, such as by a reciprocating screw arrangement, into the mold. After the material has been allowed to cool, the mold is opened and the molded part is ejected from the mold. The mold can then be closed and used for forming a subsequent part.
• the presence of the integral panel and pull ring on the interior of the spout at the time it is initially molded represents a special problem.
• the ejection of the part from the mold must occur in such a sequence as to preserve the frangible line surrounding the removable panel and the pull ring.
• the mandrel-like portion must, as part of the mold opening sequence, be removed from the molded part after the part is formed.
• removing the mandrel-like mold element is typically done by pulling or stripping the molded part from the mandrel as part of the mold opening sequence. This, however, may cause damage to the molded parts, particularly if the parts include threads or pull rings formed therein.
• One mold designed for this purpose includes a plurality of concentric, separable telescopic mold elements, and an opening therein defined by one of the base portion and the mold elements for injecting a mold material into the apparatus.
• the elements are configured such that they can be separated or removed from the mold, from the inner most element outward.
• This structure is intended to provide sufficient free space for the newly molded part to flex inward as the mold elements are removed thus minimizing the possibility of damage to the molded part.
• Each of the mold elements includes a mold face, which in part defines a mold cavity, and flange portions opposite of their respective mold faces.
• the mold also includes a movable, ball bearing type to facilitate opening the mold for removal of the molded container spout.
• the mold apparatus also includes two intermediate mold elements positioned between the inner and outer mold elements. Each of the intermediate mold elements includes openings through their respective body portions adapted to receive a movable, locking ball bearing cam member therein.
• a staged, sequentially separated injection mold of the present invention includes a base, a first mold element coupled to the base including a gate through which plastics material can be injected and a surface at least partially defining a mold cavity for receiving the plastics material.
• a core plate movable in a first direction with respect to the mold base has a core element fixed to the plate including an end surface confronting the first mold element partially defining the mold cavity.
• a sleeve surrounds the core element having an end surface confronting the first mold element, an outward facing surface, and an inward facing surface confronting the core element.
• the inward facing surface includes a channel coupled to the sleeve end surface and a circumferential groove.
• the sleeve end surface, outward facing surface and channel further defining the mold cavity.
• the core element, sleeve and stripper ring After injection of plastic into the mold cavity, the core element, sleeve and stripper ring initially move as a unit in a first direction away from the first mold element. The core element is then retracted within the sleeve by a distance sufficient to expose the channel coupled to the sleeve end surface to permit release of material from the channel.
• a set of thread splits confronts the sleeve outward facing surface and the first mold element to further define the mold cavity. The set of thread splits are movable generally orthogonally to the direction of relative movement of the core and cavity plates. An inclined outer surface is included on each of the thread splits and wedge elements are fixed to the mold base.
• Each wedge element acts between adjacent inclined outer surfaces on adjacent thread splits to force the thread splits toward the confronting sleeve outward facing surfaces upon movement of the core plate toward the mold base.
• the set of thread splits move away from the outer surface of the sidewall simultaneously with the moving of the core element, sleeve and stripper ring as a unit away from the first mold element. Stops are fixed to the stripper plate for limiting the movement of the thread splits away from the confronting sleeve outward facing surfaces.
• a stripper ring surrounding the sleeve includes an edge positioned contiguous to the sleeve outward facing surface.
• the stripper ring edge includes an arcuate portion immediately adjacent to the thread splits partially defining the mold cavity.
• the stripper ring is movable along the sleeve to facilitate removal of material from the sleeve outward facing surface.
• a stripper plate coupling means couples the stripper plate to the core plate for limiting the relative movement between the stripper plate and core plate.
• a sleeve support plate is fixed to the sleeve and coupling means couple the sleeve support plate to the core plate for delayed movement with respect to the core plate.
• the sleeve support plate After the sleeve support plate has been moved by a distance sufficient to remove the sleeve from within the container spout sidewall and to remove the pull ring from the channel on the inside surface of the sleeve, the sleeve support plate is advanced relative to the stripper plate to cause the sleeve end surface to contact the pull ring and thereby separate the container spout from the stripper ring.
• the structure of a mold of the present invention allows for a less complex set of relative movements betweens the various elements of the mold to permit release of the molded article and return of the mold to a position suitable to receive injected plastics.
• the less complex movements allows for faster and more reliable operation of the mold as compared to existing molds intended to create similar molded articles.
• Some of the simplicity comes from having certain elements of the mold perform two functions. For example, the set of thread splits confronting the sleeve outward facing surface to define the thread formation on the outer surface of the sidewall also cooperates with the first mold element to define the flange.
• the stripper ring surrounding the sleeve to facilitate removal of the molded sidewall portion of the spout from the sleeve also has an edge positioned contiguous to the sleeve outward facing surface with an arcuate portion immediately adjacent to the thread splits at least partially defining the lip of the sidewall.
• Figure 1 is a perspective view of an exemplary container spout that can be formed using the staged, sequentially separated injection mold, in accordance with the principles of the present invention, the spout being illustrated affixed to a gable top container.
• Figure 2 is a perspective view of a spout that can be formed in a staged, sequentially separated injection mold of the present invention.
• Figure 3 is a cross-sectional view of the staged, sequentially separated injection mold apparatus of the present invention for making the spout shown in Figures 1 and 2, with the mold shown in the fully closed position.
• Figure 4 is a cross-sectional view similar to that of Figure 3 with the mold moved to an open position with the thread splits retracted away from the molded spout.
• Figure 5 is a cross-sectional view similar to that of Figure 4 with the mold core plate moved even further open so that the core is moved within the sleeve to a position that will allow the pull ring to be removed.
• Figure 6 is a cross-sectional view similar to that of Figure 5 with the mold sleeve support plate moved to a further open position thereby causing the sleeve to be withdrawn from the molded article that is held by the stripper ring.
• Figure 7 is a cross-sectional view nearly identical to that of Figure 5 with the mold sleeve support plate having been returned to its former position thus causing the sleeve to move back inside the stripper ring to force the molded spout out of contact with the stripper ring.
• Figure 8 is a cross-sectional view nearly identical to that of Figure 4 with the core plate having been returned to its former position, thus completing the ejection of the molded article from the mold in preparation for the mold to close to the position shown in Figure 3 ready again to accept injected plastic.
• Figure 1 shows a container 10 that has come into widespread use having a gable top 12 including a spout 14 capped with a closure 16 for resealing the container 10 after initial opening.
• the spout 14 is shown in greater detail in Figure 2 to have a peripheral flange 18.
• a generally cylindrical sidewall 20 extends perpendicularly from an inner perimeter 22 of the flange 18 to a lip 24.
• a closure engaging formation such as a thread 26 is formed on the outer surface 28 of the sidewall 20, which interacts with a corresponding internal thread (not shown) on the closure16.
• the closure engaging formation 26 could be a snap ring near the lip 24 for interaction with a corresponding snap-on cap rather than the closure 16 with an internal thread.
• a removable panel 30 is integrally formed within the sidewall 20 forming a tamper indicating seal that can be visually inspected by a consumer of the contents of the container prior to initiating use.
• a pull ring 32 is connected to the removable panel 30 by a stem portion 34 to permit easy removal of the panel 30 by the consumer. By merely pulling on the pull ring 32, the consumer causes a rupture to develop along a generally circular line of weakness 36 at the periphery of the removable panel 30. It will be recognized by those skilled in the art that the various elements of the spout 14 are not easily formed using an injection mold.
• a mold 40 constructed according to the present invention for the purpose of forming the spout 14, is shown in Figures 3-8. While the figures only illustrate a single set of mold elements capable of forming a single spout at one time, in actual practice, the mold 40 can comprise many such sets of mold elements so that as many as 96, or even more, spouts 14 can be formed simultaneously. The illustration of merely those mold elements necessary to form a single spout at one time is for the purpose of clarity and should not be considered as limiting in any way.
• the mold 40 includes a mold base 42.
• a first mold element 44 is coupled to the base 42 and includes a gate 45 through which plastics material can be injected
• the first mold element 44 also includes a surface 46 partially defining a mold cavity 47 for receiving the plastics material, the mold cavity 47 having the shape of the spout 14.
• the surface 46 of the first mold element 44 is configured to form the obverse surface of the spout 14 from that shown in Figure 2.
• the surface 46 of the first mold element 44 includes a first portion 48 defining a lower surface of flange 18, a second portion 50 defining a inner surface of the cylindrical sidewall 20 below the removable panel 30, a third portion 52 defining the lower surface of the removable panel 30, and a ridge 54 at the junction of the second and third portions defining the circular line of weakness 36.
• a pair of camming wedges 56 are fixed to the mold base 42 on each side of the first mold element 44 to project generally perpendicularly away from the mold base 42.
• Each camming wedge 56 includes a pair of inclined surfaces 58, the function of which will become apparent from the discussion below.
• the mold 40 also includes a first core plate 60 that is reciprocally movable in direction Y with respect to the mold base 42.
• a core element 62 is fixed to the core plate 60 to project toward the first mold element 44.
• the core element 62 includes an end surface 64 that confronts a central part of the third portion 52 of surface 46 of the first mold element 44 and defines an inner portion of the upper surface of the removable panel 30.
• the core element 62 also includes a cylindrical outer surface 66.
• a second core plate 68 is fixed to the first core plate 60, and includes lines 70 for handling cooling fluids, such as chilled water, supplied to the interior of the core element 62.
• the mold 40 also includes a sleeve support plate 72 separated from the first core plate 60 by a core retaining plate 74.
• the core retaining plate 74 is fixed to the sleeve support plate 72.
• a sleeve 76 is fixed to the sleeve support plate 72 so as to surround the core element 62.
• the sleeve 76 has an end surface 78 that confronts that portion of surface 46 of the first mold element 44 to define the perimetral portion of the removable panel 30.
• the sleeve 76 also has an outward facing surface 80 that includes a forward portion defining the inner surface of the sidewall 20 of the spout 14.
• An inward facing surface 82 of the sleeve 76 confronts the core element 62 and includes a channel 84 coupled to the sleeve end surface 78 that defines the pull ring 32 and stem portion 34 of the spout 14.
• the sleeve 76 is movable with respect to the core element 62 to permit release of material from the channel 84 as explained below in connection with the steps of the molding process illustrated by Figures 5 and 6, however, the sleeve 76 is limited in its movement.
• a fastener 86 extends through the core retaining plate 74, the first core plate 60 and the second core plate 68, and is fixed to the sleeve support plate 72.
• the second core plate 68 includes a shoulder 88 that confronts a stop 90 on the fastener 86 that limits the relative movement between the sleeve support plate 72 and the second core plate 86.
• the faster 86 is surrounded by a bushing 92 that limits the travel of the plates 60, 68, 72 and 74 during their relative movement.
• the mold 40 also includes a stripper plate 94.
• a stripper ring 96 is fixed to the stripper plate 94 so as to surround the sleeve 76.
• the stripper ring 96 includes an edge 98 positioned contiguous to the sleeve outward facing surface 80. As shown in Figure 6, the edge 98 includes a portion 100 that defines the lip 24 of the spout 14.
• the stripper plate 94 and stripper ring 96 are movable relative to the sleeve 76 to facilitate removal of material from the sleeve outward facing surface 80 as explained below in connection with the steps of the molding process illustrated by Figures 5 through 7, however, the stripper ring 96 is limited in its movement.
• a fastener 99 extends through the first core plate 60, core retaining plate 74, and the sleeve support plate 72, and is fixed to the stripper plate 94.
• the first core plate 60 includes a shoulder 101 that confronts a stop 102 on the fastener 99 that limits the relative movement between the stripper plate 94 and the first core plate 60.
• the fastener 99 is surrounded by a bushing 104 that limits the travel of the plates 60, 72, 74 and 94 during their relative movement.
• Wear plate 106 is fixed to a front surface 108 of the stripper plate 94 by fastener 110.
• Thread splits 112 move along the surface of wear plate 106 for lateral movement in the direction X.
• the thread splits 112 include a thread-defining surface 114 that confronts the sleeve outward facing surface 80 and the second portion 50 of the first mold element 44 to define the threaded outer surface 20 of the spout 14.
• the thread splits 112 are movable by a biasing means or by a cam and cam follower combination (not shown) between the position shown in Figure 3 and the position shown in Figures 4-8.
• the thread splits 112 include an inclined outer surface 118 intended to be engaged by the inclined surfaces 58 of camming wedges 56 to force the thread splits 112 toward the confronting sleeve outward facing surfaces 80 upon movement of the first core plate 60 toward the mold base 42.
• the head 116 of fastener 110 is dimensioned to act as a stop to limit the outward lateral movement of the thread splits 112.
• a container spout 14 as shown in Figures 1 and 2 is formed in mold 40 by injecting a molten plastic through gate 45 while the mold is situated in a closed position as shown in Figure 3.
• the core element 62, sleeve 76 and stripper ring 96 are moved as a unit to an open position as shown in Figure 4 which has the effect of removing the molded spout 14 from contact with the surface 46 of the first mold element 40.
• the thread splits 112 are caused to move outward away from the outer surface 28 of the sidewall 20 to expose the newly formed threads 26.
• first and second core plates 60 and 68 move away from the sleeve support plate 72 and core retaining plate 74 by a distance limited by the abutment of stop 90 and shoulder 88, typically about 1.25 cm, as shown in Figure 5.
• This causes the core element 62 to be withdrawn from within the sleeve 76 by a distance sufficient to expose the channel 84 coupled to the sleeve end surface 78 that contains the pull ring 32 and stem portion 34 of the spout 14.
• the rearward movement of the first and second core plates 60 and 68 continues until the shoulder 101 on the first core plate 60 abuts stop 102 surrounding fastener 99, as shown in Figure 6.
• the sleeve support plate 72 This causes the sleeve support plate 72 to be separated from the stripper plate 94 by a distance, typically about 1.9 cm, sufficient to withdraw sleeve outward facing surface 80 from within the sidewall 20 of spout 14 so that the spout is now held by edge portion 100 of the stripper ring 96 that defines the lip 24 of the spout 14.
• the sleeve support plate 72 is moved forward until it abuts the stripper plate 94 as shown in Figure 7. This causes the sleeve end surface 78 to contact the pull ring 32 and push the molded spout 14 free from the stripper ring 96, thereby providing the molded spout 14 with some momentum so that it will be ejected from the mold 40.
• a optional air channel can be included to provide an air blast between the molded spout 14 and one or more of the stripper ring 96, core element 62, and sleeve 76 to assist in the ejection of the spout 14.
• the core plates 60 and 68 are moved to abut the sleeve support plate 72 as shown in Figure 8.
• the core plates 60 and 68, sleeve support plate 72 and stripper plate 94 are then moved as a unit to return to the closed position shown in Figure 3.
• mold 40 is illustrative of the present invention in that it allows for a very simple set of relative movements betweens the various elements of the mold to permit release of the molded article 14, and then a return of the mold to a position suitable to receive a next shot of injected plastics.
• the simple movements of the mold 40 allow for a faster and more reliable operation of the mold as compared to existing molds intended to create similar molded articles.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Closures For Containers (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=23120298

Family Applications (1)

Country Status (7)

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Citations (6)

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• 2002
  • 2002-05-15 WO PCT/US2002/015388 patent/WO2002092319A1/en active Application Filing
  • 2002-05-15 CA CA002447430A patent/CA2447430C/en not_active Expired - Fee Related
  • 2002-05-15 PL PL02368460A patent/PL368460A1/xx not_active Application Discontinuation
  • 2002-05-15 BR BR0209656-0A patent/BR0209656A/pt not_active Application Discontinuation
  • 2002-05-15 JP JP2002589236A patent/JP2004525806A/ja active Pending
  • 2002-05-15 EP EP02736861A patent/EP1387752A4/de not_active Withdrawn
  • 2002-05-15 MX MXPA03009871A patent/MXPA03009871A/es active IP Right Grant

Patent Citations (6)

Non-Patent Citations (1)

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