Two-piece quad-seal closure with plug shock absorbing end panel

A two-piece shock absorbing closure defined by a ring and a plug, the plug including a centrally generally circular unreinforced concavely axially outwardly opening end panel, an annular axially projecting plug portion bounding the end panel, the ring including an axially opening annular channel for receiving the plug portion, the annular channel being defined by inner and outer channel walls and a bight wall therebetween, a wall radially outboard of the outer channel wall responsive to insertion of the plug portion into the annular channel for radially inwardly deflecting the outer channel wall to bring the same into intimate friction engagement with the plug portion, and another wall between the end panel and the plug portion for effecting the deflection of the end panel from its concave configuration to a convex configuration in response to shock forces imparted to the closure and/or an associated container thereby absorbing said shock forces to prevent plug popping.

The present invention is an improvement in the QUAD-SEAL SNAP LOCK 
disclosed in commonly assigned, copending application Ser. No. 335,305 
filed Dec. 28, 1981. 
The present invention and that disclosed in the latter-identified 
application are directed to plug and ring closures or triple-tight 
closures which are relatively well known for packaging therein oil or 
water based paints. Such closures normally include a plug portion defined 
by inner and outer walls and a bight or bight wall therebetween and a ring 
which likewise includes a channel defined by inner and outer walls and a 
bight or bight wall therebetween. The plug portion is received in the 
channel of the ring to effect an air-tight seal which is necessarily 
desirable to prevent oxidation of the contents within an associated 
container. Over the years, it became necessary or desirable to partially 
or fully coat the plug and ring, and particularly the sealing surfaces 
thereof, to reduce oxidation but due to the low coefficients of friction 
of such coatings, plug retention capability greatly diminished and plugs 
would pop-off when the packaged can or container was dropped on its side 
to enter a labelling machine, or a shaker, or during transport, or from 
overall general abuse. The results of the latter are obvious, namely, 
lossed product, down time, cleaning costs, equipment damage, etc. 
Typical ring and plug closures which evidence such aforementioned undesired 
"plug popping" are disclosed in, for example, Henchert U.S. Pat. No. 
2,775,362 issued Dec. 25, 1956, and Erb U.S. Pat. No. 2,606,685 issued 
Aug. 12, 1952. Efforts toward reducing or preventing such plugs from 
popping from their associated rings are found in such patents as Kinnavy 
et al. (U.S. Pat. No. 3,338,456 issued Aug. 29, 1967) and Hoening et al. 
(U.S. Pat. No. 4,180,179 issued Dec. 25, 1979). In the latter-noted 
patents, coatings of low coefficients of friction and interlocking beads 
and sockets have been utilized in an effort to reduce or eliminate plug 
popping. Each introduces separate disadvantages to conventional ring and 
plug closure, namely, expensive coatings and intricate metal forming 
operations, respectively. 
In keeping with the foregoing, the invention disclosed in the aforesaid 
application provides a novel ring and plug closure of the type in which 
the plug includes a conventional plug portion defined by inner and outer 
annular friction walls and a bight wall therebetween which is received in 
an annular channel of the ring likewise defined by inner and outer 
friction walls and a bight wall therebetween, and a major object was that 
of providing means radially outboard of the outer wall of the ring channel 
which is responsive to the insertion of the plug portion into the annular 
channel for radially inwardly deflecting the outer channel wall and, thus, 
the outer friction wall of the plug to increase the frictional purchase 
between the two and effect clamping action which essentially prevents or 
greatly reduces conventional plug popping. 
The latter object is augmented by constructing the deflecting means as a 
frusto-conical wall inclined at a predetermined angle to the plane of the 
outer channel wall, and the predetermined angle progressively reduces as 
the plug portion is inserted into the channel to effectively increase the 
friction or clamping action between the plug portion and ring channel. 
Somewhat more specifically, the frusto-conical wall is joined to the outer 
channel wall by a radius in axial alignment with a curl of the plug 
whereby upon the insertion of the plug portion into the annular channel, 
the plug curl contacts and exerts a force against the radius of the ring 
which is transmitted to deflect the frusto-conical wall to lessen its 
normal predetermined angle until complete closure of the ring and plug is 
effected. 
The invention latter-defined further provided a novel ring and plug closure 
wherein the inner wall of the plug merges with a channel which receives a 
curl of the inner channel wall whereby upon complete closure four seals 
are effected, two at diametrically opposite areas of the latter-mentioned 
curl and radius and two between the inner and outer channel and plug wall. 
In keeping with the present invention the latter-defined structures and 
objects are further refined through the recognition that prior theories of 
incorporating reinforcing means, such as circular beading, strengthening 
configurations, or the like, into wall portions of the conventional plugs 
or rings to withstand the entire force in plug retention is incorrect and 
the opposite is, in fact, through, namely, by weakening end panel or end 
panel area and removing all reinforcing or strengthening features (flat 
panel) the plug retention properties and thus the anti-plug popping 
properties have been improved. Thus, in keeping with the foregoing the 
present invention includes a shock absorbing plug having a generally 
annular U-shaped plug portion defined by inner and outer plug walls and a 
bight wall therebetween, the inner and outer walls merging with a 
respective radius and a curl, a central generally circular unreinforced 
concavely axially outwardly opening end panel inboard of the radius, the 
end panel being in part defined by a frusto-conical shock absorbing 
annular wall joined by a first radius wall to the end panel and by a 
second radius wall to the first-mentioned radius, and the frusto-conical 
shock absorbing annular wall being effective for deflecting the end panel 
from its concave configuration to a convex configuration in response to 
shock forces imparted to the closure and/or its associated container 
thereby absorbing such shock forces to further prevent "plug popping" and 
conversely enhance plug retention. 
With the above and other objects in view that will hereinafter appear, the 
nature of the invention will be more clearly understood by reference to 
the following detailed description, the appended claims and the several 
views illustrated in the accompanying drawing.

A novel plug and ring closure or friction closure constructed in accordance 
with this invention is generally designated by the reference numeral 10 
and includes a plug 11 and a ring 12. The ring 12 includes an outer 
peripheral portion (unnumbered) which is secured to a container body 13, 
such as a conventional one gallon paint can by a conventional double seam 
which is generally designated by the reference numeral 14. The container 
or can 13 includes a conventional bottom (not shown) double seamed thereto 
or integrally formed therewith. 
The plug 11 of the ring and plug closure 10 is formed of metallic material 
and includes a central circular panel 15 merging with a radius 16 which in 
turn merges with a radially innermost annular wall 17. The annular wall 17 
in turn merges with a downwardly opening channel, radius or radius wall 
18, and the latter merges with an inner wall 20 of a plug portion 21 which 
additionally includes an outer annular plug wall 22 and a bight or bight 
wall 23. The outer annular plug wall 22 terminates in an outwardly 
downwardly and inwardly directed curl 24. 
A dimension D1 represents the predetermined distance between the outer 
surfaces of the walls 20, 22 of the plug portion 21. The predetermined 
dimension D2 represents the axial distance between the bottommost portion 
of the curl 24 and the bottommost portion of the bight or bight wall 23. 
The distance D3 represents the diameter of the radius 18 and the 
predetermined distance between the annular walls 17, 20. The distances D1 
through D3 have a significance which will be described hereinafter in 
conjunction with and relative to the ring 12. 
The ring 12 is also constructed from metallic material and includes an 
opening generally designated by the reference numeral character O which is 
defined by an upwardly outwardly and inwardly directed reverse curl 30 
having a terminal edge 31 terminating adjacent a radius 32. The radius 32 
merges with an inner friction or channel wall 33 of a generally U-shaped, 
upwardly opening channel 35 which includes an upwardly opening bight or 
bight wall 34 and an outer friction or channel wall 36. The walls 33, 36 
are generally normally in parallel relationship to each other or taper 
very slightly in a converging manner in an upward direction, as viewed in 
FIG. 2 of the drawing. The wall 36 merges with a downwardly opening radius 
37 which is joined by a very short cylindrical wall portion 38 to a very 
short radius 40 which in turn is joined to and merges with a 
frusto-conical wall 41 and another radius 42 defining an arc of 
approximately 135.degree.. The radius 42 is integrally joined to a 
conventional chuck wall 43 which is in turn united to the container body 
13 by the double seam 14. 
The frusto-conical wall 41 defines means which are responsive to the 
insertion of the plug portion 21 into the channel 35 for radially inwardly 
deflecting the outer channel wall 36 from the position shown in FIG. 2 to 
the position shown in FIG. 4, as will be described more fully hereinafter, 
to create an effective and high frictional gripping action between the 
respective walls 22, 36 and 20, 33. However, prior to the insertion of the 
plug 21 into the annular channel 35 of the ring 12, the frusto-conical 
wall 41 is disposed at an angle of approximately 45.degree. to a plane 
normal to the axis of the ring and/or plug and/or container body, as is 
readily apparent from FIGS. 2 and 3 of the drawings. As in the case of the 
plug 11, the ring 12 includes three predetermined dimensions pertinent to 
the present invention, one being the predetermined distance D4 which is 
the distance between the inner surfaces of the walls 33, 36. The 
predetermined distance D5 is the distance measured axially from the 
uppermost portion of the radius 36 to the lowermost inner surface of the 
bight or bight wall 34. The dimension D6 is the exterior diameter of the 
curl 30. The distance D6 is greater than the distance D3, and the 
difference therebetween is represented in FIG. 2 by the reference 
character I which indicates the interference between the size of the curl 
30 relative to the radius 18 prior to assembly. Furthermore, while the 
walls 33, 36 might be parallel and, therefore, equally spaced axially the 
distance D4 therebetween, the walls may converge or taper upwardly 
slightly which is the minimum taper produced from tooling to effect a slip 
fit to a minimum interference fit between the plug portion 21 of the plug 
11 and the channel 36 of the ring 12. The dimension D2 is at all times 
less than the distance D5. 
After a product has been packaged in the container body 13, the plug 11 is 
axially aligned with the opening O, as indicated in solid lines in FIG. 2, 
and is then moved toward and to the phantom outline position shown in FIG. 
2. In the phantom outline position of FIG. 2, the walls 20, 22 are in 
frictional bearing contact with the inner surfaces of the respective walls 
33, 36, and if at any time prior to such insertion the distance D4 was 
less than the distance D1, then the walls 33, 36 would spread slightly to 
accommodate the plug portion 21. The latter is thus far typical of the 
conventional insertion of a conventional plug portion into a conventional 
ring channel. During the continued insertion of the plug portion 21 into 
the ring channel 35 a position is eventually reached at which the bottom 
of the plug curl 24 contacts and rests upon the uppermost portion of the 
radius 37, as is illustrated in FIG. 3. At this point, the reverse curl 30 
is introduced into the radius 18 and, thus, the interference I is overcome 
by the inward deflection of the wall 17, as is evident in FIG. 3. In the 
position shown in FIG. 3, the predetermined angle (generally 45.degree.) 
of the frusto-conical wall 41 remains unchanged from the original position 
of FIG. 2 prior to the introduction of the plug portion 21 into the 
angular channel 35. 
As a continued downward axial force is applied to the plug 11, the curl 24 
bears against the radius 37 and this force is transmitted to the 
frusto-conical wall 41 to cause the latter to progressively deflect 
radially inwardly and downwardly to progressively reduce the angles of the 
frusto-conical wall 41 from the original 45.degree. to 44.degree., 
43.degree., 42.degree., etc., until the same approaches or reaches a plane 
normal to the axis of the ring 11, the plug 12, and the container body 13, 
as is most readily apparent from FIG. 4 at which time a complete seal is 
effected between the plug 11 and the ring 12. During this downward 
insertion of the plug portion 21 into the channel 35, the relative 
dimensions D2, D5 remain unchanged and, thus, the bight 23 of the plug 
portion 21 never contacts the bight 34 of the annular channel 35. 
Accordingly, the axial downward force of the plug 11 upon deflecting the 
frusto-conical wall 41 progressively downwardly and inwardly creates ever 
increasing inwardly directed forces F1 through the radiuses 40, 37 and, 
thus, inwardly deflecting the outer channel wall 36, as indicated by the 
forces F1 of FIG. 4. These forces F1 about the periphery of the wall 36 
deflect the latter radially inwardly and likewise deflect the outer plug 
wall 22 radially inwardly creating an upwardly converging relationship 
between the walls 22, 36 and 20, 33, as is readily evident from FIG. 4. 
The forces F1 are not simply directed radially inwardly, as indicated in 
FIG. 4 but, obviously, travel through the metal of the channel 35 and 
result in (a) a slight bulging in the overall diameter of the bight wall 
34 as compared to the normal dimension thereof shown in FIGS. 2 and 3, (b) 
a progressive convergence of the walls 20, 33 relative to the walls 22, 36 
as the bight wall 34 progressively bulges to the position shown in FIG. 4, 
and (c) continued inward deflection of the annular wall 17 as the curl 30 
seats fully within the radius 18. In the final seated condition (FIG. 4) 
of the plug 11 relative to the ring 12, a quad-seal or four seals are 
created, and these are generally designated in FIG. 4 by the reference 
characters S1, S2, S3 and S4. Furthermore, due to the upward convergence 
of the walls 22, 36 relative to the walls 20, 33, a snap lock, so to 
speak, is created between the plug portion 21 and the channel 35 which 
precludes the accidental "popping" of the plug 11. In order to remove the 
plug 11, a tool, such as the blade end of a screwdriver, must be inserted 
beneath the curl 24 and the latter progressively wedged upwardly to 
relieve the forces F1 acting against the wall 36 by in effect permitting 
the frusto-conical wall 41 to rebound from the position shown in FIG. 4 to 
the position shown in FIG. 3 after which the plug or portion 21 can be 
readily removed from the channel 35. 
It is also pointed out that during the transformation of the plug and ring 
from the position shown in FIG. 3 to that shown in FIG. 4, the curl 30 
also further slightly moves forward toward the radius 18 thereby 
additionally deflecting the plug wall 20 radially outwardly by imparting 
thereto forces F2. Thus, though the deflection of the frusto-conical wall 
from the position shown in FIGS. 2 and 3 to the position shown in FIG. 4 
is the major motivation for creating the four seals S1 through S4 and the 
snap lock of the convergent walls 22, 36 and 20, 33, the latter are also 
augmented by the forces F2 attributed to the dimensional relationships of 
the radius 18 and the curl 30. 
Reference is now made to FIGS. 5 and 6 of the drawings wherein is 
illustrated another novel plug and ring closure or friction closure 
constructed in accordance with this invention and the same is generally 
designated by the reference numeral 50. Many elements of the closure 50 
which correspond to elements of the closure 10 are identically numbered 
and primed for convenience as, for example, the radius 40', the wall 41', 
the radius 42', etc. As in the case of the closure 10, the plug and ring 
closure 50 includes a plug 51 and a ring 52. The ring 52 includes an outer 
peripheral portion (unnumbered) which is secured to a container body 53, 
such as a conventional one gallon paint can by a conventional double seam 
which is generally designated by the reference numeral 54. The container 
or can 53 includes a conventional bottom (not shown) double-seamed thereto 
or integrally formed therewith. 
The plug 51 of the ring and plug closure 50 is formed of metallic material 
and is designed to resist shock forces imparted thereto under abuse of the 
closure and/or its container, as for example, when the same is dropped. 
The shock absorbing feature includes wall means 60 which includes a 
central generally circular unreinforced concavely axially outwardly 
opening wall 61 including a central circular end panel 62 and a 
frusto-conical annular wall 63 having a major circumferential portion 64 
and a minor circumferential portion 65 with the latter being joined by a 
first radius wall 66 to the end panel 62. The first radius wall 66 is 
spaced by the frusto-conical annular wall 63 from a second radius wall 67 
which is in turn merged with a radially innermost annular wall 57 of the 
plug 51. The wall means 63 and particularly the components 61-67 thereof 
effect deflection of the end panel 62 and the frusto-conical annular wall 
from its normally axially outwardly concavely opening condition (FIG. 5) 
to a convexly axially outwardly projecting position (FIG. 6) in response 
to shock forces imparted to the closure and/or its associated container 
thereby absorbing such shock forces to prevent "plug popping". Such forces 
are indicated by the line of force F in FIGS. 5 and 6, and it is to be 
understood that this force F might be created simply by dropping the 
container which, when packaged with a liquid such as paint, exerts a force 
against the closure and any of its components 61 through 67 tending to 
"pop" the plug 51, but in lieu thereof the force F of FIG. 5 simply is 
absorbed by the flexure or movement of the panel from the position shown 
in FIG. 6 to that shown in FIG. 5. 
The annular wall 57 of the plug 51 in turn merges with a downwardly opening 
channel, radius or radius wall 58, and the latter merges with an inner 
wall 70 of a plug portion 71 which additionally includes an outer annular 
plug wall 72 and a bight or bight wall 73. The outer annular plug wall 72 
terminates in an outwardly, downwardly and inwardly directed curl 74. 
The dimensions D1, D2 and D3 associated with the plug 51 corresponds to the 
respective dimensions D1-D3 of the plug or plug portion 21 and thus a 
further description thereof is unnecessary. 
The ring 52 is identical in construction to the ring 12 and thus the 
various components of the ring 52 corresponding to those of the ring 12 
have simply been added to FIGS. 5 and/or 6 of the drawings are are primed 
to reflect the identity of structure and function, including the 
dimensions D4, D5 and D6. Accordingly, the operation of the structure of 
the plug 51 and its cooperation with the ring 52 is identical to that 
heretofore described relative to the plug 11 and the ring 12 of the plug 
and ring closure 10, particularly in regard to the operation of the 
elements 40', 41', 42', etc., which functions identically to the like 
elements of the closure 10 during the insertion of the plugs 11 or 51 
(FIGS. 2 and 3) into the rings 12 or 52 (FIGS. 4 and 5, 6). 
Although only a preferred embodiment of the invention has been specifically 
illustrated and described herein, it is to be understood that minor 
variations may be made in the apparatus without departing from the spirit 
and scope of the invention, as defined in the appended claims.