CA2121279C - Tamper resistant closure cap with bubbled threads - Google Patents
Tamper resistant closure cap with bubbled threadsInfo
- Publication number
- CA2121279C CA2121279C CA002121279A CA2121279A CA2121279C CA 2121279 C CA2121279 C CA 2121279C CA 002121279 A CA002121279 A CA 002121279A CA 2121279 A CA2121279 A CA 2121279A CA 2121279 C CA2121279 C CA 2121279C
- Authority
- CA
- Canada
- Prior art keywords
- closure
- flange
- ring
- threads
- container
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
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
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/42—Moulds or cores; Details thereof or accessories therefor characterised by the shape of the moulding surface, e.g. ribs or grooves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D50/00—Closures with means for discouraging unauthorised opening or removal thereof, with or without indicating means, e.g. child-proof closures
- B65D50/02—Closures with means for discouraging unauthorised opening or removal thereof, with or without indicating means, e.g. child-proof closures openable or removable by the combination of plural actions
- B65D50/04—Closures with means for discouraging unauthorised opening or removal thereof, with or without indicating means, e.g. child-proof closures openable or removable by the combination of plural actions requiring the combination of simultaneous actions, e.g. depressing and turning, lifting and turning, maintaining a part and turning another one
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D55/00—Accessories for container closures not otherwise provided for
- B65D55/02—Locking devices; Means for discouraging or indicating unauthorised opening or removal of closure
- B65D55/06—Deformable or tearable wires, strings, or strips; Use of seals, e.g. destructible locking pins
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Closures For Containers (AREA)
Abstract
A closure has a central portion with a periphery and a skirt extending from the periphery, a tear strip extending from the skirt, a tamper evident band extending from the tear strip and a movable flange extending from the band. The flange is hinged so that the tamper evident band has equally spaced windows in it to make it flexible so that it can be stretched over the ring with a very small tolerance or even a negative tolerance relative to the ring. Once the flange has overridden the ring, a free edge of the flange moves inward to rest against an outer surface of the neck beneath the ring. The closure can then not be removed from the container without first severing the tabs as the flange will not override the ring during removal of the closure. The tabs are severed by manually grasping a handle of the tear strip and removing the tear strip.
When the tear strip is removed, the closure functions in a conventional manner for opening and closing the container. The screw thread on the closure is made up of elongated bubbles located end to end. A core for a mold to make the closure containing the bubbled screw threads can be manufactured using a ring-shaped electrode having a cylindrically-shaped inner surface. The electrode is connected to a high voltage source and mounted in an electrical discharge machine, there being a contact point on said inner surface for each bubble to be formed in said screw thread.
With previous devices, the closure contains conventional screw threads and dusting is a major problem or, the flange does not contain windows and cannot be manufactured on a large scale with appropriate tolerances.
When the tear strip is removed, the closure functions in a conventional manner for opening and closing the container. The screw thread on the closure is made up of elongated bubbles located end to end. A core for a mold to make the closure containing the bubbled screw threads can be manufactured using a ring-shaped electrode having a cylindrically-shaped inner surface. The electrode is connected to a high voltage source and mounted in an electrical discharge machine, there being a contact point on said inner surface for each bubble to be formed in said screw thread.
With previous devices, the closure contains conventional screw threads and dusting is a major problem or, the flange does not contain windows and cannot be manufactured on a large scale with appropriate tolerances.
Description
This invention relates to a tamper resistant closure for use on a container and to a method of manufacturing a core of a mold to form screw threads of a closure made up of elongated bubbles.
For safety and security reasons, tamper resistant closures are known. One such previous closure is described in European Patent Application Number 90310078.2 published on April 10th, 1991. The closure in that Application has a tamper evident band having a movable flange thereon with the band being connected to the closure along a weakened line. The weakened line can be formed by scoring or by circumferentially-spaced bridges. When the closure is installed on the container, the flange and tamper evident band override a ring on the container. When the closure is desired to be removed, sufficient force must be exerted on the closure 'o sever the tamper evident band and flange from the rest of the closure along the weakened line. A disadvantage of this closure is that the weakened line must be designed within a very fine tolerance, one that is not always satisfactorily achieved during manufacture.
PCT Application No. US 91/05434 published on March 5th, 1992 describes a tamper indicating closure having a retaining hoop with relief windows extending from a hinged edge at least one-third of the distance toward a free edge. The windows are located to interrupt the hinged edge and create a series of spaced hinges around the circumference of the closure. The windows are located along the hinged edge so that the retainer can be moved from an outward molded position to an inward installation position much more easily so that the retainer does not have to be moved between the two positions by a separate step. With the present invention, t~e windows are spaced from the hinged edge.
In Car.adian Patent No. 1,182,782 issued on February l9th, 1985, there is described a closure and container with screw threads made up of a series of projections in the shape of truncated cones so that the screw threads of the closure and container can interlock with one another.
The projections were made by drilling successive holes into a core for use in a mold. The separate drilling of each hole can be extremely time consuming particularly when the spacing between holes and the depth of each hole must be ident~al.
It is an object of the present invention to provide a tamper resistant closure having a tear strip in combination with a flange hinged onto a tamper evident band where the flange has windows located therein so that the flange can be manufactured with an extremably small or even negative tolerance relative to a ring of a container and still be made to fit over said ring during installation without severing the tear strip.
It is a further object of the present invention to provide a method of manufacturing a core for a ~.old where the core contains depressions to create a screw thread in a closure where the screw thread is a series o~
elongated bubbles located end to end.
A tamper resistant closure is used on a container having a neck surrounding an opening said necX
having external threads thereon, said neck having a ring located beneath said threads when the container is in an upright position. The closure has a central portion having a periphery with a skirt extending from said periphery, a tear strip extending from said skirt, a tamper evident band affixed to said tear strip and a movable flange extending from said band. The tear strip is affixed to said skirt by severable attachment means.
The skirt has an interior surface with threads thereon corresponding to the threads on said container. The flange is co~,nected to said band by hinging means so that ~ 2121279 said flange extends inwardly relative to said band an.d a free edge of said flange is movable between an upper position and a lower position. The flange has a plurality of spaced windows located therein, said windows S being spaced fr~m said hinging means and being substantially centrally located between said hinging means and said free edge. The central por~ion, skirt, strip, band and flange are sized to fit snugly on said neck so that when the threads of the neck are engaged with the threads of the closure, the closure is in a closed position relative to said container. The free edge of said flange is located above said hinging means and beneath said ring. The flange overrides said ring as the closure is installed on said container. The flange engages said ring when the closure is attempted to be removed from said container to prevent said flange from overriding said ring, said band and flange being detachable from said skirt by manually seve.ing said attachment means to remove said tear strip.
A method of manufacturing a core of a mold to form screw threads made up of elongated bubbles located end to end, said core having a cylindrically-shaped outer surface thereon, said method using a ring-shaped electrode having a cylindrically-shaped inner surface thereon, said electrode being sized to fit over said cylindrically-shaped outer surface of said core, with equally-spaced contact points on said inner surface, said electrode being connected to a high voltage source and mounted in an electrical discharge machine, there being a contact point on said inner surface for each bubble to be formed in said screw thread, contacting one contact point of said electrode for every two vertically spaced bubble-shaped depressions that are to be cut into said core, said method comprising moving the electrode such that one contact point contacts said outer surface at a time to '- 2121279 burn at least one bubble into said outer surface, moving the electrode so that a second contact edge cuts at least one more bubble into said ou~er surface, repeating this process until each contact poir.t around the circumference of the electrode contacts an outer surface of said core to burn oblong bubble shapes into said core so that said bubble shapes form a screw thread around said core from end to end, each contact edge cutting two vertically aligned bubbles where parts of the screw threads are to be vertically spaced from one another.
In the drawings:
Figure 1 is a perspective view of a closure and a container where the closure has a bubbled screw thread and a flange with windows thereon;
Figure 2 is a partial perspective view of a bubbled screw thread;
Figure 3 is a partial front view of a bubbled screw thread;
Figure 4 is a partial perspective view of a closure with a flange exte~ding upward;
Figure 5 is a partial perspective view of a closure with a flange extending downward;
Figure 6 is a perspective view of an electrode and core spaced apart from one another;
Figure 7 is a schematic top view of an electrode and core in one ~osition;
Figure 8 is a schematic top view of the electrode and core in a different position from that shown in Figure 7;
Figure 9 is a schematic top view of the core and electrode in a different position from that shown in Figures 7 and 8; and Figure 10 is a cross-sectional view of a further embodiment of a closure and part of a container _ 4 _ ~ 2121279 where a tear strip and tamper evident ~and are one component.
In Figure 1, a closure 50 is located above a container 4. The container 4 has a neck 6 with conventional external screw threads 8 thereon. The neck 6 has a ring 10 located beneath the threads 8 when the container is in an upright position as shown in said Figure. The closure 50 has a central portion 52 with a periphery 54 and a skirt 56 extending from said periphery. A tear strip 58 extends from the skirt 56 and a tamper evident band 60 extends from the tear strip 58.
A movable flange ~2 extends from the band 60. The tear strip 58 is affixed between the skirt 56 and the band 60 by severable attachment means, being a plurality of severable tabs 64. On the flange 62 are a plurality of spaced windows 66. The skirt 56 has an interior surface 68 with screw threads 70 thereon. The screw threads 70 can be one continuous screw thread or can be several partial threads or any suitabie combina~io~ in between.
The screw thr~ads 70 are made up of a plurality of elongated bubbles 72 that are located end to end to one another to form a screw thread. With conventional threads, when installing plastic closures on plastic containers using a capping machine, and particularly, a high speed capping machine, there is a large amount of dusting produced from the corresponding screw threads on the closure and container during installation. Dusting refers to fine particles of plastic that break free from the closure and/or the containers due to friction during installation of the closure. Dusting is still a serious problem whether the container is made of glass or plastic. Particularly when the container is used for food, the amount of dusting from conventional screw threads has been found to be unacceptable. With the elongated bubble threads 70 of the pre~ent invention, the _ 5 _ amount of dusting that occurs is reduced by approximately 75~ over conventional screw threads.
In Figures 2 and 3, the shape of the bubbles 72 can be seen more clearly. From Figure 3 it can be seen that the bubbles 72 are relatively flat on a bottom 74 and rounded outward on a top 76. Generally, the bubbles can be described as having a curved oblong surface (the cross-section of which is shown in Figure 10) with rounded edge. The edges are not 90~ as shown in Figures 2 and 3.
In Figures 4 and 5, there is shown an enlarged partial perspective view of the flange 62 and tamper evident band 60. The flange 62 is connected to the tamper evident band 60 by hinging means 78. From Figure 4, it can be seen that the flange 62 has a plurality of equally spaced windows 66 located therein.
The windows 66 are spaced apart from the hinging means 78 and are generally substantially centrally located between the hinging means 78 and an inner edge 80 of said flange.
The position of the flange 62 shown in Figure 4 is the approximate position of the flange when it is installed beneath the ring 10 of the container 4. In Figure 5, the flange has been moved further apart from the tamper evident band 60 to expose an interior surface 82 of said flange. It can be seen that there are two lateral ribs 84 located between each window 66. The purpose of the lateral ribs 84 is to provide lateral strength to the flange 62 so that it will not bend laterally once it is installed on a container. If a flange were to bend laterally, it would be possible to turn the closure off a container without severing the tabs 64. The purpose of the windows 66 is to provide longitudinal flexibility to the flange 62 so that the inner edge 80 can be stretched over the ring 10 even though an inside diameter of the flange 80 when the flange is in a rest position is ~ - 2121279 smaller than an outside diameter of the ring 10. Thus, it can be seen that the flange 62 can be stretched relatively easily over the ring 10. The flange 62 could be designed with only one ridge located between each window rather than two ridges. ~he windows can be completely open or they can be closed with a thin film of plastic or other closure material.
In Figure 6, there is shown an electrode 86 located above a core 88. The electrode 86 has a plurality of contact points 90. The contact points gO
are located on vertical edges 91. An inside diameter of the contact points 90 is slightly larger than an outside diameter of the core 88 so that an outer surface 92 of the core 88 can fit within the electrode 86. The electrode 86 is mounted into a conventional electrical discharge machine (not shown) and a high voltage is ap lied to said electrode. The core 88 is mounted within the electrode 86 with the surface 92 adjacent to the contact points 90. When it is desired to create two bubble forming grooves verti~ally apart from one another, there are two contact points 90 located vertically apart from one another on the same vertical edge 91.
As shown in Figures 7, 8 and 9, the electrode 86 is moved slightly relative to the core 88 so that one of the contact points 90 of the electrode 86 contacts the outer surface 92 of the core 88. In the portion of the outer surface 92 shown in Figure 6, there are two rows of grooves 94 in the shape of inverted elongated bubbles arranged end to end to form a screw thread. As each contact point contacts the outer surface 92, one groove for one inverted elo~gated bubble for each row is burned in~o the core 88. The contact points 90 are 5~ apart from one another and the electrode 86 is therefore moved 5~ at a time relative to the core 88 until all of the contact points around the electrode 90 have successively contacted the o~er surface 92 of the core 88. The distance of movement shown in Figures 7, 8 and 9 is greatly exaggerated to approximately 1200 between each figure as a 5~ distance would not be noticeable.
Depending on ~he size of bubbles that one wished to create, the distance between contact points on adjacent edges could be more or less than 50. From Figure 6, it can be seen that the grooves 94 are relatively flat on a bottom and rounded outward on a top so that when the core is used in a mold to form the closure with the elongated bubbled screw threads, the screw threads can be removed from the core ~ithout damaging them. The core is then used in a conventional molding machine to form a closure.
The closure is placed into a bending machine to rotate the flange to an inward position.
In Figure 10, in a further embodiment of the invention, a closure 96 is identical to the closure 50 shown in Figure 1 down to the tear strip. With the closure 96, the tear strip and tamper evident band are combined into one component so that when the tear strip is pulled, the band and tear strip are removed along with the flange 62. The tear strip/band 98 has a handle 100.
When the handle is pulled, tabs 64 are severed and the tear strip band 98 pulls away from the skirt 56.
Preferably, though not shown in Figure 10, approximately the last approximately 10~ in circumference of the tear strip band 98 is affixed to the skirt so that an end of the band 98 opposite to the handle 100 remains affixed to the skirt to discourage a user from discarding the band 98 separately from the skirt. This feature will reduce pollution caused by discarded bands. If a user wishes to tear the band completely off the skirt, he or she will be able to do so by cutting it off or by applying an appropriate force. The sectional view of the screw thread 70 shows the cross-sectional shape to a centre of bubbles 72. It can be seen that the upper surface of each bubble 72 is rounded outward relative to the lower surface of each bubble. It can also be seen that edges of the bubble are rounded. Where the cross-sectional shape, shown in Figure 10, differs from the shape of the bubbles 72 shown in Figures 1 and 2, the shape in Figure 10 is the preferred shape. Further, the cross-sectional shape of the ring 10 and of the standard screw thread 8 of the container 4 are also shown.
The present invention has a significant advantage over previous tamper resistant closures in that the use of the hinged flange 62 allows variations in the relative size of the closure and container within acceptable tolerances. Also, the tabs 64 can be made with a great deal of strength. This strength can be increased by increasing the number or size of the tabs 64. Since the tabs 64 are severed by manually pulling the tear strip 58, the tabs 64 are severed one at a time, if the two sets of tabs are alternated or, if the two sets of tabs are vertically aligned with one another at the rate of two at a time.
With previous tamper resistant closures using the hinged flange 62 and tabs or a scored line, the removal of the closure requires that all of the tabs or the entire scored line be severed virtually simultaneously.
Sometimes, a great deal of strength is required to sever the tabs or the scored line. With the present invention, the tabs can be severed easily, singly or in pairs, while always providing more than sufficient strength to ensure that the tabs do not sever prematurely during the initial installation of the closure on the container or during shipping and handling. The present invention permits a broad range of design relating to the strength of the tabs.
_ g _ ~- 2121279 Further, the windows permit the flange of the closure to be designed with an inside diameter significantly smaller than an outside diameter of said ring on the container. This is particularly important for large closures (for example, those having a diameter greater than 7 cm). By giving the flange greater flexibility, the windows enable the capping machine to differentiate between the torque required to turn the closure onto the container over the ring and the final torque required to tighten the closure. The torque required to turn the closure over the ring is no more than 75% of the final torque. Further, when the container is made from plastic material rather than from glass, the container will flex somewhat and it is even more important to size the closure within very close tolerances relative to the container. In addition, the bubble threads can greatly reduce dusting to acceptable levels. Bubble-shaped screw threads can also be used on the container.
For safety and security reasons, tamper resistant closures are known. One such previous closure is described in European Patent Application Number 90310078.2 published on April 10th, 1991. The closure in that Application has a tamper evident band having a movable flange thereon with the band being connected to the closure along a weakened line. The weakened line can be formed by scoring or by circumferentially-spaced bridges. When the closure is installed on the container, the flange and tamper evident band override a ring on the container. When the closure is desired to be removed, sufficient force must be exerted on the closure 'o sever the tamper evident band and flange from the rest of the closure along the weakened line. A disadvantage of this closure is that the weakened line must be designed within a very fine tolerance, one that is not always satisfactorily achieved during manufacture.
PCT Application No. US 91/05434 published on March 5th, 1992 describes a tamper indicating closure having a retaining hoop with relief windows extending from a hinged edge at least one-third of the distance toward a free edge. The windows are located to interrupt the hinged edge and create a series of spaced hinges around the circumference of the closure. The windows are located along the hinged edge so that the retainer can be moved from an outward molded position to an inward installation position much more easily so that the retainer does not have to be moved between the two positions by a separate step. With the present invention, t~e windows are spaced from the hinged edge.
In Car.adian Patent No. 1,182,782 issued on February l9th, 1985, there is described a closure and container with screw threads made up of a series of projections in the shape of truncated cones so that the screw threads of the closure and container can interlock with one another.
The projections were made by drilling successive holes into a core for use in a mold. The separate drilling of each hole can be extremely time consuming particularly when the spacing between holes and the depth of each hole must be ident~al.
It is an object of the present invention to provide a tamper resistant closure having a tear strip in combination with a flange hinged onto a tamper evident band where the flange has windows located therein so that the flange can be manufactured with an extremably small or even negative tolerance relative to a ring of a container and still be made to fit over said ring during installation without severing the tear strip.
It is a further object of the present invention to provide a method of manufacturing a core for a ~.old where the core contains depressions to create a screw thread in a closure where the screw thread is a series o~
elongated bubbles located end to end.
A tamper resistant closure is used on a container having a neck surrounding an opening said necX
having external threads thereon, said neck having a ring located beneath said threads when the container is in an upright position. The closure has a central portion having a periphery with a skirt extending from said periphery, a tear strip extending from said skirt, a tamper evident band affixed to said tear strip and a movable flange extending from said band. The tear strip is affixed to said skirt by severable attachment means.
The skirt has an interior surface with threads thereon corresponding to the threads on said container. The flange is co~,nected to said band by hinging means so that ~ 2121279 said flange extends inwardly relative to said band an.d a free edge of said flange is movable between an upper position and a lower position. The flange has a plurality of spaced windows located therein, said windows S being spaced fr~m said hinging means and being substantially centrally located between said hinging means and said free edge. The central por~ion, skirt, strip, band and flange are sized to fit snugly on said neck so that when the threads of the neck are engaged with the threads of the closure, the closure is in a closed position relative to said container. The free edge of said flange is located above said hinging means and beneath said ring. The flange overrides said ring as the closure is installed on said container. The flange engages said ring when the closure is attempted to be removed from said container to prevent said flange from overriding said ring, said band and flange being detachable from said skirt by manually seve.ing said attachment means to remove said tear strip.
A method of manufacturing a core of a mold to form screw threads made up of elongated bubbles located end to end, said core having a cylindrically-shaped outer surface thereon, said method using a ring-shaped electrode having a cylindrically-shaped inner surface thereon, said electrode being sized to fit over said cylindrically-shaped outer surface of said core, with equally-spaced contact points on said inner surface, said electrode being connected to a high voltage source and mounted in an electrical discharge machine, there being a contact point on said inner surface for each bubble to be formed in said screw thread, contacting one contact point of said electrode for every two vertically spaced bubble-shaped depressions that are to be cut into said core, said method comprising moving the electrode such that one contact point contacts said outer surface at a time to '- 2121279 burn at least one bubble into said outer surface, moving the electrode so that a second contact edge cuts at least one more bubble into said ou~er surface, repeating this process until each contact poir.t around the circumference of the electrode contacts an outer surface of said core to burn oblong bubble shapes into said core so that said bubble shapes form a screw thread around said core from end to end, each contact edge cutting two vertically aligned bubbles where parts of the screw threads are to be vertically spaced from one another.
In the drawings:
Figure 1 is a perspective view of a closure and a container where the closure has a bubbled screw thread and a flange with windows thereon;
Figure 2 is a partial perspective view of a bubbled screw thread;
Figure 3 is a partial front view of a bubbled screw thread;
Figure 4 is a partial perspective view of a closure with a flange exte~ding upward;
Figure 5 is a partial perspective view of a closure with a flange extending downward;
Figure 6 is a perspective view of an electrode and core spaced apart from one another;
Figure 7 is a schematic top view of an electrode and core in one ~osition;
Figure 8 is a schematic top view of the electrode and core in a different position from that shown in Figure 7;
Figure 9 is a schematic top view of the core and electrode in a different position from that shown in Figures 7 and 8; and Figure 10 is a cross-sectional view of a further embodiment of a closure and part of a container _ 4 _ ~ 2121279 where a tear strip and tamper evident ~and are one component.
In Figure 1, a closure 50 is located above a container 4. The container 4 has a neck 6 with conventional external screw threads 8 thereon. The neck 6 has a ring 10 located beneath the threads 8 when the container is in an upright position as shown in said Figure. The closure 50 has a central portion 52 with a periphery 54 and a skirt 56 extending from said periphery. A tear strip 58 extends from the skirt 56 and a tamper evident band 60 extends from the tear strip 58.
A movable flange ~2 extends from the band 60. The tear strip 58 is affixed between the skirt 56 and the band 60 by severable attachment means, being a plurality of severable tabs 64. On the flange 62 are a plurality of spaced windows 66. The skirt 56 has an interior surface 68 with screw threads 70 thereon. The screw threads 70 can be one continuous screw thread or can be several partial threads or any suitabie combina~io~ in between.
The screw thr~ads 70 are made up of a plurality of elongated bubbles 72 that are located end to end to one another to form a screw thread. With conventional threads, when installing plastic closures on plastic containers using a capping machine, and particularly, a high speed capping machine, there is a large amount of dusting produced from the corresponding screw threads on the closure and container during installation. Dusting refers to fine particles of plastic that break free from the closure and/or the containers due to friction during installation of the closure. Dusting is still a serious problem whether the container is made of glass or plastic. Particularly when the container is used for food, the amount of dusting from conventional screw threads has been found to be unacceptable. With the elongated bubble threads 70 of the pre~ent invention, the _ 5 _ amount of dusting that occurs is reduced by approximately 75~ over conventional screw threads.
In Figures 2 and 3, the shape of the bubbles 72 can be seen more clearly. From Figure 3 it can be seen that the bubbles 72 are relatively flat on a bottom 74 and rounded outward on a top 76. Generally, the bubbles can be described as having a curved oblong surface (the cross-section of which is shown in Figure 10) with rounded edge. The edges are not 90~ as shown in Figures 2 and 3.
In Figures 4 and 5, there is shown an enlarged partial perspective view of the flange 62 and tamper evident band 60. The flange 62 is connected to the tamper evident band 60 by hinging means 78. From Figure 4, it can be seen that the flange 62 has a plurality of equally spaced windows 66 located therein.
The windows 66 are spaced apart from the hinging means 78 and are generally substantially centrally located between the hinging means 78 and an inner edge 80 of said flange.
The position of the flange 62 shown in Figure 4 is the approximate position of the flange when it is installed beneath the ring 10 of the container 4. In Figure 5, the flange has been moved further apart from the tamper evident band 60 to expose an interior surface 82 of said flange. It can be seen that there are two lateral ribs 84 located between each window 66. The purpose of the lateral ribs 84 is to provide lateral strength to the flange 62 so that it will not bend laterally once it is installed on a container. If a flange were to bend laterally, it would be possible to turn the closure off a container without severing the tabs 64. The purpose of the windows 66 is to provide longitudinal flexibility to the flange 62 so that the inner edge 80 can be stretched over the ring 10 even though an inside diameter of the flange 80 when the flange is in a rest position is ~ - 2121279 smaller than an outside diameter of the ring 10. Thus, it can be seen that the flange 62 can be stretched relatively easily over the ring 10. The flange 62 could be designed with only one ridge located between each window rather than two ridges. ~he windows can be completely open or they can be closed with a thin film of plastic or other closure material.
In Figure 6, there is shown an electrode 86 located above a core 88. The electrode 86 has a plurality of contact points 90. The contact points gO
are located on vertical edges 91. An inside diameter of the contact points 90 is slightly larger than an outside diameter of the core 88 so that an outer surface 92 of the core 88 can fit within the electrode 86. The electrode 86 is mounted into a conventional electrical discharge machine (not shown) and a high voltage is ap lied to said electrode. The core 88 is mounted within the electrode 86 with the surface 92 adjacent to the contact points 90. When it is desired to create two bubble forming grooves verti~ally apart from one another, there are two contact points 90 located vertically apart from one another on the same vertical edge 91.
As shown in Figures 7, 8 and 9, the electrode 86 is moved slightly relative to the core 88 so that one of the contact points 90 of the electrode 86 contacts the outer surface 92 of the core 88. In the portion of the outer surface 92 shown in Figure 6, there are two rows of grooves 94 in the shape of inverted elongated bubbles arranged end to end to form a screw thread. As each contact point contacts the outer surface 92, one groove for one inverted elo~gated bubble for each row is burned in~o the core 88. The contact points 90 are 5~ apart from one another and the electrode 86 is therefore moved 5~ at a time relative to the core 88 until all of the contact points around the electrode 90 have successively contacted the o~er surface 92 of the core 88. The distance of movement shown in Figures 7, 8 and 9 is greatly exaggerated to approximately 1200 between each figure as a 5~ distance would not be noticeable.
Depending on ~he size of bubbles that one wished to create, the distance between contact points on adjacent edges could be more or less than 50. From Figure 6, it can be seen that the grooves 94 are relatively flat on a bottom and rounded outward on a top so that when the core is used in a mold to form the closure with the elongated bubbled screw threads, the screw threads can be removed from the core ~ithout damaging them. The core is then used in a conventional molding machine to form a closure.
The closure is placed into a bending machine to rotate the flange to an inward position.
In Figure 10, in a further embodiment of the invention, a closure 96 is identical to the closure 50 shown in Figure 1 down to the tear strip. With the closure 96, the tear strip and tamper evident band are combined into one component so that when the tear strip is pulled, the band and tear strip are removed along with the flange 62. The tear strip/band 98 has a handle 100.
When the handle is pulled, tabs 64 are severed and the tear strip band 98 pulls away from the skirt 56.
Preferably, though not shown in Figure 10, approximately the last approximately 10~ in circumference of the tear strip band 98 is affixed to the skirt so that an end of the band 98 opposite to the handle 100 remains affixed to the skirt to discourage a user from discarding the band 98 separately from the skirt. This feature will reduce pollution caused by discarded bands. If a user wishes to tear the band completely off the skirt, he or she will be able to do so by cutting it off or by applying an appropriate force. The sectional view of the screw thread 70 shows the cross-sectional shape to a centre of bubbles 72. It can be seen that the upper surface of each bubble 72 is rounded outward relative to the lower surface of each bubble. It can also be seen that edges of the bubble are rounded. Where the cross-sectional shape, shown in Figure 10, differs from the shape of the bubbles 72 shown in Figures 1 and 2, the shape in Figure 10 is the preferred shape. Further, the cross-sectional shape of the ring 10 and of the standard screw thread 8 of the container 4 are also shown.
The present invention has a significant advantage over previous tamper resistant closures in that the use of the hinged flange 62 allows variations in the relative size of the closure and container within acceptable tolerances. Also, the tabs 64 can be made with a great deal of strength. This strength can be increased by increasing the number or size of the tabs 64. Since the tabs 64 are severed by manually pulling the tear strip 58, the tabs 64 are severed one at a time, if the two sets of tabs are alternated or, if the two sets of tabs are vertically aligned with one another at the rate of two at a time.
With previous tamper resistant closures using the hinged flange 62 and tabs or a scored line, the removal of the closure requires that all of the tabs or the entire scored line be severed virtually simultaneously.
Sometimes, a great deal of strength is required to sever the tabs or the scored line. With the present invention, the tabs can be severed easily, singly or in pairs, while always providing more than sufficient strength to ensure that the tabs do not sever prematurely during the initial installation of the closure on the container or during shipping and handling. The present invention permits a broad range of design relating to the strength of the tabs.
_ g _ ~- 2121279 Further, the windows permit the flange of the closure to be designed with an inside diameter significantly smaller than an outside diameter of said ring on the container. This is particularly important for large closures (for example, those having a diameter greater than 7 cm). By giving the flange greater flexibility, the windows enable the capping machine to differentiate between the torque required to turn the closure onto the container over the ring and the final torque required to tighten the closure. The torque required to turn the closure over the ring is no more than 75% of the final torque. Further, when the container is made from plastic material rather than from glass, the container will flex somewhat and it is even more important to size the closure within very close tolerances relative to the container. In addition, the bubble threads can greatly reduce dusting to acceptable levels. Bubble-shaped screw threads can also be used on the container.
Claims (11)
1. A tamper resistant closure for use on a container having a neck surrounding an opening, said neck having external threads thereon, said neck having a ring located beneath said threads when the container is in an upright position, said closure comprising a central portion having a periphery with a skirt extending from said periphery, a tear strip extending from said skirt, a tamper evident band affixed to said tear strip and a movable flange extending from said band, said tear strip being affixed to said skirt by severable attachment means, said skirt having an interior surface with threads thereon corresponding to the threads on said container, said flange being connected to said band by hinging means so that said flange extends inwardly relative to said band and a free edge of said flange is movable between an upper position and a lower position, said flange having a plurality of spaced windows located therein, said windows being spaced from said hinging means and being substantially centrally located between said hinging means and said free edge, said central portion, skirt, strip, band and flange being sized to fit snugly on said neck so that when the threads of the neck are engaged with the threads of the closure, the closure is in a closed position relative to said container and the free edge of said flange is located above said hinging means and beneath said ring, the flange overriding said ring as the closure is installed on said container, said flange engaging said ring when the closure is attempted to be removed from said container to prevent said flange from overriding said ring, said band and flange being detachable from said skirt by manually severing said attachment means to remove said tear strip.
2. A closure as claimed in Claim 2 wherein the windows are equally spaced from one another.
3. A closure as claimed in Claim 2 wherein at least one of the windows is closed by a thin layer.
4. A closure as claimed in Claim 2 wherein the threads are a series of elongated bubbles located end to end in the shape of a screw thread.
5. A closure as claimed in any one of Claims 1, 2 or 4 wherein the threads are a series of elongated bubbles located end to end in the shape of a screw thread and said bubbles are identical to one another and are located in vertical alignment with one another where parts of the screw thread are located vertically adjacent to each other.
6. A closure as claimed in any one of Claims 1, 2 or 4 wherein the threads are a series of elongated bubbles located end to end in the shape of a screw thread and said bubbles are relatively flat on a bottom and curved outwards on a top.
7. A closure as claimed in any one of Claims 1, 2 or 4 wherein said tear strip is affixed between said skirt and said band by severable attachment means, said tear strip being removable while leaving said band on said container separated from said skirt.
8. A closure as claimed in any one of Claims 1, 2 or 4 wherein there are a plurality of lateral ribs located on said flange, said ribs extending between said windows.
9. A method of manufacturing a core of a mold to form screw threads made up of elongated bubbles located end to end, said core having a cylindrically-shaped outer surface thereon, said method using a ring-shaped electrode having a cylindrically-shaped inner surface thereon, said electrode being sized to fit over said cylindrically-shaped outer surface of said core, with equally-spaced contact points on said inner surface, said electrode being connected to a high voltage source and mounted in an electrical discharge machine, there being a contact point on said inner surface for each bubble to be formed in said screw thread, contacting one contact point of said electrode for every two vertically spaced bubble-shaped depressions that are to be cut into said core, said method comprising moving the electrode such that one contact point contacts said outer surface at a time to burn at least one bubble into said outer surface, moving the electrode so that a second contact edge cuts at least one more bubble into said outer surface, repeating this process until each contact point around the circumference of the electrode contacts an outer surface of said core to burn oblong bubble shapes into said core so that said bubble shapes form a screw thread around said core from end to end, each contact edge cutting two vertically aligned bubbles where parts of the screw thread are to be vertically spaced from one another.
10. A method as claimed in Claim 9 wherein successive bubbles are formed by contact points that are substantially 5° apart from one another.
11. A method as claimed in Claim 10 wherein the bubbles are formed to be rounded outwards on a top and to be relatively flat on a bottom.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002121279A CA2121279C (en) | 1994-04-14 | 1994-04-14 | Tamper resistant closure cap with bubbled threads |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002121279A CA2121279C (en) | 1994-04-14 | 1994-04-14 | Tamper resistant closure cap with bubbled threads |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2121279A1 CA2121279A1 (en) | 1995-10-15 |
| CA2121279C true CA2121279C (en) | 1999-07-13 |
Family
ID=4153380
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002121279A Expired - Lifetime CA2121279C (en) | 1994-04-14 | 1994-04-14 | Tamper resistant closure cap with bubbled threads |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2121279C (en) |
-
1994
- 1994-04-14 CA CA002121279A patent/CA2121279C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2121279A1 (en) | 1995-10-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |
Effective date: 20140414 |