Three Piece Thermoplastic Container
A container for a material, wherein the container has a body, a base, and a lid is presented. The base may be with or without a tamper-evident feature, depending on requirements, while the lid is made preferably of a clear, transparent plastic. The body has a bottom and a tubular element defining sides of the body and extending upwardly from a periphery of the bottom. An upper portion of the tubular element forms an aperture of the body. The base has an externally directed annular protrusion which engages a recess in the aperture-forming portion of the tubular element of the body. In this way, a permanent seal is made at the top of the body after filling with the material. A lid is adapted to removably engage a top portion of the base.
This application claims the benefit of priority to U.S. provisional patent application Ser. No. 61/257,118 filed Nov. 2, 2009, now pending, the disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTIONThe invention relates to the field of containers, and more particularly to thermoplastic cans for shipping and storing materials.
BACKGROUND OF THE INVENTIONThe current application incorporates by reference the Thermoplastic Can presented by U.S. Pat. No. 7,419,068, hereinafter referred to as the '068 patent, granted on Sep. 2, 2008 to Maxwell Bushby; international publication no. WO/2003/055754 (info enclosed). International counterparts are as follows: Australian Patent No. 2002351876 (info enclosed); South African Patent No. 2004/5794; Australian Design Registration No. 152397 (info enclosed); New Zealand Patent No. 533257 (info enclosed); Indian Patent No. 208441 (info enclosed); Philippines Patent Appl. No. 12004450967; and Malaysian Patent No. 20042500. The Abstract of patent '068 specifies: “A thermoplastic can (1) comprising a thermoplastic body (2) having a disc like top (3) molded as one with a tubular element (5) defining the sides of the body (2) and extending downwardly from the peripheral portions of the top (3); an openable portion associated with the top to facilitate use of the can contents by an end user, a thermoplastic base member (7) having an externally directed protrusion (8) engaged in a relatively thin walled recess (9) in the radially internally facing lower peripheral portion of the body thereby effecting a permanent seal at the base of the container after filling thereof; the resistance to permanent inward deformation of the externally directed protrusion exceeding the resistance to permanent outward deformation of the thin walled recess; the wall thickness of the lower peripheral portion of the body below the thin walled recess exceeding that of the thin walled recess.”
The majority of paints on the market are supplied in tin cans with tin covers, either lacking tamper-evident features or having tamper-evident features constructed of a different material, such as plastic, the combination of materials not only requiring a complicated manufacturing and installation process, but rendering such containers un-recyclable in facilities where separation cannot be achieved by use of machinery.
The present invention relates to a thermoplastic can of a three piece design comprising a paint can (container), a base, and a lid, wherein a permanent base to container seal is effected between a peripheral portion of the base and an internally facing surface adjacent the aperture of the can (similar with the seal of the '068 patent), further presenting an openable attachment of lid to base, the lid being made of preferably transparent plastic to allow visibility to the contents of the can package. Paint can, base and lid are made of thermoplastic material, hence being recyclable as a unit.
BRIEF SUMMARY OF THE INVENTIONThe present application builds on the design of the '068 thermoplastic can, presenting a can-to-base closure with three circumferential seals similar in principle to the seal of the '068 patent, and further adding a lid-to-base closure with another set of three circumferential seals. The base may be with or without tamper-evident feature, depending on requirements, while the lid is made preferably of a clear, transparent plastic that allows instant color verification (i.e. a re-opening of the lid for color verification is not necessary). While the object of the present invention is intended for use as paint can package, it may be used for any applications where it is desired for the contents of the can to be visible without opening the lid. No particular comments are made regarding the size of the paint can package, other than to specify it is envisioned for a comprehensive range of sizes as to be commercially useful.
For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which:
A detailed description of the preferred embodiment of the invention follows with reference to
As can be seen in
With reference to
As can be seen in
As base 12 is installed in paint can 10 at the aperture 16, protrusion 36 flexes inwardly to ride over the inner surface of rim 28, flexing outwardly again to bite into recess 25 while its sloped bottom surface 32 comes into contact with sloped surface 20 of paint can. The thickness differential between membrane 25a and rim 28 allows the membrane to flex radially outwardly as base 12 is installed. Once protrusion 36 comes to rest in recess 25, the superior ‘memory’ of the thickened rim 28 returns it to its original diameter. Similar to the behavior explained in the '068 patent, this succession of motions is possible due to the fact that the thin membrane 25a undergoes some plastic deformation, while the thickened rim 28 undergoes an elastic deformation during installation of base into paint can. A membrane thickness of 0.006″ to 0.032″ is recommended in order for the thin walled recess to deform outwardly during installation of the base and thereafter.
Once installation has thus been achieved, base 12 and paint can 10 form a first seal 34 at surfaces 20 and 32, a second seal 42 at surfaces 24 and 38, and a third seal 44 at surfaces 26 and 40.
The thickness of annular projection 36 is such that its resistance to permanent inward deformation exceeds the resistance to permanent outward deformation of thin walled recess 25 due to the fact that protrusion 36 has a 30-35% thicker cross-section than that of thin walled recess 25. It is obvious that once the base is installed in the paint can, it cannot be disengaged without permanently damaging these two components.
The outermost edge 39 of protrusion 36 (which bites into thin walled recess 25) should preferably be rounded. While a larger radius would ease installation of base into paint can, it should however be sufficiently small to not overly reduce the surface area coverage of seals 42 and 44, values of R0-0.030″ being a suitable compromise.
Similar to the design of the '068 patent, the paint can and base should preferably have a slight interference or friction fit, such that when the base is secured between surfaces 20 and 26 of paint can, there is an interference of 0.000″-0.002″. With reference to the embodiment presented here, surfaces 26 and 40 should have an angle between 15° and 45° with the horizontal, but preferably 24°-32°. Further similar with the '068 patent, the angle of protrusion 36 is recommended to be between 20° and 45° with the vertical.
Furthermore, the maximum diameter of protrusion 36 is larger than the maximum diameter of recess 25 into which it is fitted. This interference fit is critical to the seal of the paint can, and, while dependent on capacity and size of paint can, it is preferably in the range of 0.004″ to 0.028″.
Further with reference to
As can be seen in
In order for the thickened rim 48 to snap into its seat in the lid, surface 52 rides along the tip and inner surface of ridge 80, slightly flexing radially inwardly while forcing ridge 80 to flex radially outwardly. As rim 48 reaches up and into contact with ridge 68 of lid, it is guided along both sides into its seat. As can be seen in
As rim 48 snaps into its seat in the lid, it is held snugly between surfaces 78, 72, and 70, forming the three circumferential seals described above.
As can be seen in
The overwhelming majority of paint cans on the market are tin cans with tin lids, having no tamper-evident feature. White paint is supplied, with the tint being added upon sale of the paint. After color blending, the seller typically opens the lid to reveal the color to the customer, and may smear a smidge of paint on the lid as further visual proof of the content.
The invention presented here brings considerable improvement over existing art. Firstly, panel 58, molded integrally with base 12, provides a tamper-evident feature over current designs. The three circumferential seals of base 12 to paint can 10, together with the three circumferential seals of base 12 to lid 14, protect the paint while preventing leaks.
Another major improvement of the present invention is that by using a transparent lid, the color is visible without necessitating a re-opening of the paint can for color verification. This provides not only for faster service, but also prolongs the life of the paint by preventing air or contaminants from entering the paint can cavity until the end user accesses the paint.
As can be seen in
A second embodiment of the invention is presented with reference to
The closure of the '068 design presented in
As can be noticed in
As shown in
Furthermore, while the embodiments presented here are of circular design, it should be understood that rectangular, square, oval and oblong cross-sections are also considered.
Although the present invention has been described with respect to one or more particular embodiments, it will be understood that other embodiments of the present invention may be made without departing from the spirit and scope of the present invention. Hence, the present invention is deemed limited only by the appended claims and the reasonable interpretation thereof.
Claims
1. A container for holding a material, the container comprising:
- a body having a bottom and a tubular element defining sides of the body and extending upwardly from a periphery of the bottom, wherein an upper portion of the tubular element forms an aperture of the body;
- a base having an externally directed annular protrusion which engages a recess in the aperture-forming portion of the tubular element of the body thereby effecting a permanent seal at the top of the body after filling thereof; and
- a lid adapted to removably engage a top portion of the base.
2. The container of claim 1, wherein one or more of the body, the base, or the lid are formed from a thermoplastic material.
3. The container of claim 2, wherein one or more of the body, the base, or the lid are fabricated from a Polyolefin such as PET or PEN.
4. The container of claim 2, wherein one or more of the body, the base, or the lid is transparent.
5. The container of claim 1, wherein the aperture-forming portion of the tubular element further comprises an internally directed annular protrusion configured to stop further insertion of the base when the base is inserted into the aperture of the body and contacts the internally directed annular protrusion.
6. The container of claim 1, wherein the externally directed annular protrusion extends externally and upwardly and is therefore capable of flexing inwardly whilst being introduced into the aperture of the body of the container prior to coming to rest in the recess.
7. The container of claim 1, wherein the resistance to permanent inward deformation of the externally directed protrusion exceeds the resistance to permanent outward deformation of the recess due to the radially externally directed protrusion being fabricated from thicker thermoplastic material than that present in the recess.
8. The container of claim 1, wherein the radially externally directed protrusion comprises 3 surfaces each of which, when the base is disposed in the aperture of the body, forms a seal with a corresponding surface of the aperture-forming portion of the tubular element of the body.
9. The container of claim 1, wherein the base further comprises:
- an inner annular projection extending upward; and
- a horizontal continuous panel for enclosing the material in the container.
10. The container of claim 8, wherein the body further comprises a handle disposed on the horizontal continuous panel, and the horizontal continuous panel is configured to be removed from the base by applying force to the handle.
11. The container of claim 1, wherein the lid further comprises a continuous central panel, continued to enclose the material in the container when the lid is engaged with the base.
12. The container of claim 1, wherein the lid further comprises a first downwardly projecting portion for sealing engagement with an inner surface of a rim of the base and a second downwardly projecting portion for sealing engagement with an outer surface of the rim of the base.
13. The container of claim 1, wherein a base-engaging portion of the lid comprises 3 surfaces each of which, when the lid is affixed to the base, forms a seal with a corresponding surface of a rim of the base.
14. The container of claim 1, wherein the lid comprises a bump on a top surface of the lid, the bump configured for stacking a second containers.
15. The container of claim 1, wherein when the lid is engaged with the base, the lid also contacts the body.
16. A method of enclosing a material in a tamper evident container, the method comprising the steps of:
- providing a body, the body having a bottom and a tubular element extending upwardly from a periphery of the bottom;
- placing the material into the body;
- inserting a base into a top aperture of the body, the base having a tamper-evident horizontal continuous panel, wherein the base is configured to be permanently affixed to the body once inserted; and
- engaging a removable lid on the base.
Type: Application
Filed: Nov 2, 2010
Publication Date: Aug 4, 2011
Inventors: Vince Ciccone (Kleinburg), Maxwell Bushby (Sydney)
Application Number: 12/917,864
International Classification: B65D 53/02 (20060101); B65D 25/28 (20060101);