Patent application title: PLASTIC PRY-OFF PAINT CAN ASSEMBLY
Letica Corporation (Rochester, MI, US)
Anton Letica, Ii (Bloomfield Hills, MI, US)
John R. Selina (Brighton, MI, US)
Wayne J. Harper (Macomb Township, MI, US)
IPC8 Class: AB65D4302FI
Class name: Closures removable closure situated by resilient distortion and retained by preformed configuration (e.g., detent) closure interlocked by upward opening trough at passage mouth
Publication date: 2013-03-28
Patent application number: 20130075413
An all plastic paint container assembly comprising a container, a ring
assembly attached to the rim of the container and a pry-off plastic
closure having a dual sealing arrangement with the ring member and an
undercut lock at a location which provides maximum circumferential area
and lies directly under the highest point on the closure. Containers of
this design can be stacked both with and without the ring members
attached. Three embodiments are disclosed, providing double and triple
closure locks and multiple seals.
1. A cylinder assembly comprising: a straight-sided cylindrical container
with a closed bottom and an integral side wall forming an annular top
rim; an annular plastic ring having a peripheral portion defining an
inverted U-shaped channel adapted to receive and be secured to said top
rim, and an integral inner portion forming an upwardly opening U-shaped
ring section defining an outer annular wall and an unbraced inner annular
wall, the space between said ring walls forming a deep, upward opening
annular channel for receiving a complemental annular closure channel;
said ring having a radial land between said peripheral portion and said
outer wall; a plastic closure configured to fit into said ring and having
an inner deck bounded by an annular portion having inner, middle and
outer annular walls, the inner and middle walls forming said complemental
closure channel, and the middle and outer walls forming an upwardly
opening U-shaped annular channel; said closure channel being dimensioned
to fit sealingly into the upwardly opening ring channel to close and seal
said container assembly, said outer annular closure wall terminating in
an integral, radially outwardly-extending flange that overlies said land
in spaced relation thereto when said closure is sealingly applied to said
ring; no part of said closure being higher than the top of said flange;
an undercut lock formed between the outermost closure wall and the
outermost ring wall; said undercut lock lying directly under said flange;
and said closure and ring being configured to produce sealing contact
between both sides of the outer ring wall and both inner surfaces of said
inverted U-shaped closure.
2. An assembly as defined in claim 1 further including a downwardly-extending lip on said flange to act as a splash guard when reapplying said closure to said ring.
3. A container assembly as defined in claim 1 wherein said upwardly opening U-shaped closure channel being complemental to the U-shaped channel of said annular plastic ring so as to fit sealingly therein and being of such depth as to engage said undercut lock before the closure channel bottoms out in the ring channel;
4. A container assembly as defined in claim 3 further comprising a radial clearance between the flange and the peripheral ring portion.
5. A pry-off plastic container assembly as defined in claim 1 wherein the container bottom has radially adjacent inner annular tongue and outer annular groove portions, said tongue fitting into said radial clearance when stacked with the container having a ring member attached, said groove receiving the rim in stacked relationship when containers are stacked without a ring member attached.
6. A pry-off plastic container assembly as defined in claim 1 further including a second undercut lock between the middle wall of the closure and the outer surface of the inner ring wall.
7. A pry-off plastic container assembly as defined in claim 1 further including a second undercut lock between the inner wall of the closure and the outer surface of the inner ring wall.
8. A plastic container assembly comprising: a container having a closed, integral bottom, and a generally cylindrical sidewall integral with said bottom and terminating in an unflanged upper rim; a ring member attached to the top rim of the container by way of an inverted U-shaped channel structure which fits over and onto the unflanged top rim of the container, said ring member defining radially inwardly of said inverted U-shaped channel a recessed land integral with an annular structure having, in section, a U-shaped channel with outer and inner walls; said container assembly further comprising a closure having a central deck portion and an inverted U-shaped peripheral structure having an outer edge flange and which fits matingly and sealingly into the U-shaped channel of the ring member between the outer and inner walls of said ring member; an undercut lock between the outer wall of the closure and the inner surface of the outer wall of the ring member; and a container bottom defining an upwardly extending recess which, when the container is stacked atop another similar container, is located to receive therein the rim structure of a similar container with no ring member attached thereto, the bottom structure further having radially inwardly spaced from said recess a downwardly projecting annular rib structure which extends parallel to the ring member rim structure toward the recessed land to laterally stabilize a container stacked atop another container with a ring member attached thereto.
9. A plastic container assembly as defined in claim 8 wherein said closure is configured such that the edge flange has substantially directly over said undercut lock and no part of said closure, when applied to an upright container, is higher than said edge flange.
10. A plastic container assembly as defined in claim 9 wherein the ring member is configured to have a radial land adjacent and below the plant of said channel structure to form a clearance with said edge flange when the closure is sealingly applied to the ring member.
11. A molded plastic paint can comprising: a plastic container having a closed bottom and a cylindrical sidewall integral with the closed bottom and terminating in a circular rim; a plastic ring member attached to said rim and defining a U-shaped channel spaced radially inwardly of said rim by an annular land which lies in a plane below said rim; a plastic closure having a peripheral structure forming a U-shaped channel that fits sealingly within the U-shaped channel of said ring, said peripheral structure including an outwardly extending flange that overlies said land in spaced relation to form a pry area; an undercut lock formed by and between the outermost annular mating surfaces of its ring member and closure channels directly under said flange; the top of said flange lying in the highest plane of said closure when applied to said ring member.
12. The paint can defined in claim 11 wherein a downwardly projecting annular lip is formed on the outer edge of said flange.
13. A plastic container combination comprising: a one-piece plastic container having a closed bottom and an open top with a circular rim; a plastic ring member attached to the top rim and defining a U-shaped channel radially inwardly of said rim; and a closure having a multi-planar upper surface and a U-shaped channel that fits sealingly into the U-shaped channel of the ring member; first and second radially spaced undercut locks formed between said ring member and said closure; both of said undercut locks directly underlying points on the surface of the closure that lie in the highest plane of the closure.
RELATED CASE INFORMATION
 This application is a continuation of U.S. application Ser. No. 12/765,257 filed under attorney docket no. LTC-138-B on Apr. 22, 2010, currently pending, which application is a continuation-in-part of U.S. application Ser. No. 12/540,585 filed under attorney docket no. LTC-138-A on Aug. 13, 2009, currently pending. The content of the U.S. patent application Ser. Nos. 12/765,257 and 12/540,585 are incorporated herein by reference.
FIELD OF THE INVENTION
 This invention relates to containers and more particularly to a container assembly which is particularly well suited for paint and which comprises a pry off plastic closure sealingly nested into a ring attached to the top rim of a container.
BACKGROUND OF THE INVENTION
 Paint cans and lids have been traditionally been made of steel. There are a number of disadvantages associated with steel paint cans including cost, weight, a propensity to rust, and disposal issues.
 As a result, a number of steps have been taken toward the development of plastic container assemblies for paint. In general, such an assembly comprises the container itself, an annular ring adapted to be attached to the top rim of the container and defining an upwardly opening U-shaped channel to receive a closure, and a closure or lid having an annular feature which is formed to complementally fit into the upwardly opening U-shaped channel in the ring member to produce a seal. An example is shown in U.S. Pat. No. 6,588,618 assigned to Letica Corporation of Rochester, Michigan.
SUMMARY OF THE INVENTION
 The present invention provides a container assembly of the type generally described above but having a number of features and advantages over prior plastic container assemblies.
 According to a first aspect of the invention, the ring assembly adapted to be attached to the top rim of the container has an upwardly opening U-shaped channel defined by inner and outer radially spaced concentric walls. The closure comprises an inner deck portion and a "corrugated" peripheral portion defining annular inner, middle, and outer walls, all made integral with one another by radial, curved bridge sections, and defining both an outermost upwardly opening U-shaped channel at an innermost downwardly opening or "inverted" U-shaped channel. The upwardly opening channel defines a smooth, annular surface which is complemental to and fits nestingly within the upwardly-opening U-shaped channel of the ring member whereas the inverted U-shaped channel receives the upstanding innermost end wall of the ring member and provides seals on both inner and outer surfaces thereof to prevent paint or other contained fluid from entering the space between the two complemental U-shaped channels.
 In accordance with a further aspect of the invention, a closure adapted to fit complementally into a snap ring as described above wherein a downwardly-extending lip is added to the radially outermost element of the closure. This lip extends downwardly toward, but does not touch the top surface of the ring just inside of the rim-engaging portion and provides several advantages hereinafter described.
 In accordance with a still further aspect of the invention, an undercut-type lock is formed between the outermost wall of the closure and the outer wall of the ring assembly thereby locating the lock in that portion of the overall combination of components which has the largest circumferential dimension thereby giving the lock greater surface area and improving drop test performance. In addition, locating the lock in this area takes advantage of the natural spring effect between the ring member and the outer wall of the closure thereby making it easier to remove the closure. However, in an alternative embodiment, an additional lock may be provided between the inner surface of the inner ring wall and the adjacent closure wall. In this embodiment, multiple locks and multiple seals are provided. The term "lock" is used herein to refer to an undercut, interference fit between two radially adjacent plastic walls which makes disengagement of those walls from one another more difficult, but not impossible, to achieve. This term is commonly used in this manner in the plastic container technology.
 In accordance with a further aspect of the invention, the bottom of the pail or container is formed with a downwardly projecting annular tongue and, radially outwardly thereof, an annular groove. The radius of the annular groove is such that, when two such containers are stacked atop one atop the other, before the ring member is attached to the container, the top rim of the container fits into the grove and enhances the stackability of the two containers. At the same time, the downwardly projecting annular tongue fits into a radial gap between the closure and a step formed between the peripheral portion of the ring member and the outer wall of the ring member so as to provide a laterally stable stacking relationship between two containers when a ring member is attached to the bottommost container in the stack. Therefore, as a result of the invention, assembled containers can be stacked both with and without attached ring members while lateral stability in the stack is provided.
BRIEF DESCRIPTION OF THE DRAWINGS
 The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:
 FIG. 1 is a side view of a container assembly embodying the invention;
 FIG. 2 is a cross-section of the closure detail for the container assembly of FIG. 1;
 FIG. 3 is a side view showing stacked containers; and
 FIG. 4 is a detail of the stacked containers showing the stackability of the containers with a ring member attached;
 FIG. 5 is a detail of stacked containers before the ring member is attached.
 FIG. 6 is a sectional view of an alternative embodiment providing a double lid lock;
 FIG. 7 is a sectional view of a second alternative embodiment with a double lid lock;
 FIG. 8 is a sectional view of a third alternative embodiment with a triple lid lock; and
 FIG. 9 is a sectional view of a lid with a lip feature as described above.
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT
 Referring to FIG. 1, there is shown a container assembly 10 comprising a molded plastic, one gallon cylindrical container 12 having an essentially non-tapered, cylindrical side wall 14 and an integral closed bottom 16. The container side wall 14 terminates in an embedded upper peripheral rim 18. The container assembly 10 is, in this instance, made entirely of high density polyethylene but it will be apparent to those skilled in the art that other plastic materials and blends thereof may be used.
 In accordance with the invention, an annular ring member 20 is secured to the top rim 18 of the container 12 by means of adhesive. Again, other attachment methodologies may be used including spin welding, heat welding and snap-tight interference fits.
 The ring member 20 comprises a peripheral portion 22 having a downwardly opening annular groove 23 which is adapted and sized to receive the upper rim portion 18 of the container side wall 14 therein. The ring member 20 further comprises a radially innermost portion defining an upwardly opening U-shaped channel having a radially outer annular wall 24 and, concentric therewith, a radially inner annular wall 26. The walls 24, 26 are made integral by means of a bight or bridge section 27. A step 28 on the inside of the peripheral portion 22 results in a recessed land 30 which leads into an undercut tab 34 on the inner surface of the outer wall 24 to provide a lock between the ring 20 and a closure 36, hereinafter described. Ring member 20 projects outwardly from the wall 24 at 32 into contact with the inner surface of the container sidewall 14 when the ring member 20 is in place on a container 12 as shown in FIG. 2. The innermost annular wall 26 is unbraced as shown.
 Continuing with the description of FIG. 2 embodiment, the injection molded plastic closure 36 comprises an inner planar deck portion 38 and a series of radially spaced annular walls 40, 42 and 44 of which wall 40 is the innermost wall, wall 42 is a middle wall and wall 44 is the outermost wall. Wall 44 terminates in a flange 46 which, when the closure 36 is installed in the ring member 20, exhibits a radial clearance from the step 28 as well as a uniform 360° vertical clearance from the land 30 such that a prying tool may be inserted between the flange and the ring member to pry the closure 36 from the ring member to access the contents of the container 12.
 The complemental second half of the undercut lock is provided by means of a tab 48 formed on the outer surface of the outer closure wall 44 so as to interfit with the tab 34 to provide an undercut lock of large circumferential dimension when the upwardly opening U-shaped channel 36 is complementally interfit into the upwardly opening U-shaped channel of the ring member 20. The lock 34, 48 lies directly under the flange 46. The flange 46 extends to the topmost plane of the closure as shown in FIG. 2.
 The leg 40 is made to have a slightly greater radius than the unbraced leg 26. Thus, a first seal 50 is formed by firm radial contact between the radially innermost wall 26 of the ring member 20 and the inner surface of the inner radially innermost wall 40 of the closure 36 when the closure is pressed into position in the ring member 20. A second seal is formed by close and firm radially contacting relationship between the inner surface of the innermost wall 26 of the ring member 20 and an annular tab 52 on the middle wall 42 of the closure 36. This dual seal arrangement prevents paint from entering into the space 54 between the ring member 20 and the closure 36 thus providing a cleaner paint-free closure when it is first removed from the container by the end user. The closure channel does not bottom out in the ring channel before the lock 34, 48 engages.
 Referring now to FIGS. 3, 4 and 5, the relationship between two containers 12, 12' in stacked relationship on the two conditions will be illustrated and described. In FIG. 4, the lower container 12 has the ring member 20 attached to the container and a closure 26 attached to the ring member 20. The bottom 16 of the uppermost container 12' is shown to exhibit an upwardly opening groove 55 and, radially inwardly thereof, a land 58 which is adjacent a downwardly projecting annular tongue 56. As shown in FIG. 4, with the ring member 20 attached to the container 12, the downwardly projecting tongue 56 fits into the radial clearance between the flange 46 and the step 28 to provide lateral stability between the two containers in the stacked relationship.
 As shown in FIG. 5, when containers are stacked without the ring member 20 being attached to either container, the top rim 18, being of the same radial dimension as the groove 55, fits into the groove such that the outermost ring 60 provides lateral stability preventing movement between the two stacked containers.
 FIGS. 6, 7 and 8 illustrate alternative embodiments of the invention providing additional closure (lid) locks and seals. In all cases, the container 12 remains unchanged, as do the details of how the ring members 20', 20'' and 20''' are attached to the container 12.
 Referring to FIG. 6, the ring member 20' has the lock 34' identical to lock 34 of the FIG. 2 embodiment, but has a lock/seal area 70 formed on the inside surface of the outer annular wall 26'. The closure 36 has the "corrugated" or serpentine, double-channel periphery like the FIG. 2 embodiment, but the lock feature 52 here interacts with the feature 70 on the ring to provide a second lid lock as well as an additional seal to seal area 50.
 Referring to FIG. 7, the container 12 receives a ring structure 20'' and the ring structure 20'' again receives the closure (lid) 36. Like the FIG. 6 embodiment, locks are provided at both 72 and 74. However, the upstanding annular wall 26' is made thicker and seals with both inside surfaces of the lid 36 when the lid is fully engaged with the ring 20''; i.e., the seals are at 76 and 78.
 In FIG. 8, the ring 20''' has undercuts 80 and 82 on both sides of the wall 26'', thus providing a triple lid lock as well as a triple seal; i.e., seals are formed between the closure (lid) and ring at all of 84, 86 and 88.
 FIG. 9 shows an alternative embodiment to include a container 12a, a snap ring 20a and a closure 36a. The elements are similar to the corresponding elements 12, 20 and 36 of FIG. 2 and interact in essentially the same way. The exception is the addition of the lip 90 to the radially outermost element of the closure 36a. Lip 90 extends downwardly toward, but does not contact the deck 30a of the ring 20a. The lip 90 provides these additional advantages:
 (1) it adds structural strength to the closure;
 (2) it aids in securing an opening tool such as a pry bar to remove the closure 36a from the ring; and
 (3) it acts as a splash guard when replacing the closure 36a on the ring 20a in the event paint has collected in the U-shaped channel just to the left of the ring section 20a shown in FIG. 9 (also shown at 54 in FIG. 2.)
 FIG. 9 also shows a slight clearance between the top of the container 12a and the inner surface of the ring channel which receives it. An undercut 92 provides a snap fit. Radial structure 32a is arranged integrally with outer wall 20a of the ring similar to structure 32 in the embodiment of FIG. 2.
 It will be understood that the invention has been described with reference to a specific embodiment thereof and with various features, proportions and dimensions of the embodiment shown can be changed without departing from the spirit and scope of the invention.
Patent applications by John R. Selina, Brighton, MI US
Patent applications by Wayne J. Harper, Macomb Township, MI US
Patent applications by LETICA CORPORATION
Patent applications in class Closure interlocked by upward opening trough at passage mouth
Patent applications in all subclasses Closure interlocked by upward opening trough at passage mouth