Receptacles – Closures – With closure opening arrangements for means
Reexamination Certificate
1999-01-22
2001-02-20
Shoap, Allan N. (Department: 3727)
Receptacles
Closures
With closure opening arrangements for means
C215S317000, C220S724000, C220S784000, C220S915000
Reexamination Certificate
active
06189719
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a plastic cover for a metal container and, more particularly, to a plastic cover which is removable from the metal container to allow the plastic cover and the metal container to be separately recycled. The cover is especially suited for aerosol cans.
2. Prior Art
A typical aerosol can has a plastic cover which is attached at the upper face of a metal container. The container holds its contents under pressure and the cover has a nozzle which allows the user to release the contents from the container. The cover is usually firmly attached to the container by the interaction between a lip on the cover and a top lip or curl of the container. Because of the tight lock between the lip of the cover and the curl of the container, the two are recycled together, rather than separately. Because the container and cover are made of different materials, there is a need to separate the two for efficient recycling.
One suggestion for making the cover easily removable from the container is suggested in Japanese Patent Application No. 9-52584. The teachings of the '584 application are illustrated in FIGS.
6
A-
6
C. As shown in
FIGS. 6A-6C
, cover
7
is attached to container
8
. Cover
7
has nozzle
71
and inner cylinder
72
with an opening or discontinuous portion
72
′. Attached to inner cylinder
72
is lip
73
, which is shown as two sections. Each section has two circumferential ends
74
and a side portion
74
′. Lip
73
is uniform in dimensions throughout, i.e. from circumferential end to circumferential end. Outer cylinder
75
has press point
76
which is used to deform cover
7
into an elliptical shape as shown in FIG.
6
C. When cover
7
is deformed into this elliptical shape, cover
7
can be removed from container
8
. Conventionally, cover
7
is molded from a plastic material into one piece and container
8
is made of metal.
Metal container
8
has a sloping wall section
81
, curl
82
and stem
83
. Stem
83
along with the other structure, not shown, allows for the contents of container
8
to be jetted out of container
8
. Curl
82
interacts with lip
73
to hold cover
7
onto container
8
in a conventional way. Stem
83
fits through nozzle
71
as shown in FIG.
6
A.
To assemble cover
7
on container
8
, cover
7
is pushed down onto container
8
and lip
73
forces inner cylinder
72
to flex outward while lip
73
rides over curl
82
. Lip
73
then locks into the concave portion under curl
82
and holds cover
7
onto container
8
.
To remove cover
7
from container
8
, the user pushes on press point
76
to force cover
7
into an elliptical shape as shown in
FIG. 6C. A
gap forms between curl
82
and side portion
74
′ of lip
74
and cover
7
can be removed from container
8
.
Although the arrangement in
FIGS. 6A-6C
allows cover
7
to be removed from container
8
, there is a need to improve this arrangement and make it easier to separate the two components, cover
7
and container
8
.
SUMMARY OF THE INVENTION
A plastic cover which is easily removed from a metal container has now been discovered. The cover of the present invention is easily removed from the container because it employs a curl engaging member which has at least two circumferential ends, wherein the circumferential ends have a degree of engagement with the curl that is less than the degree of engagement between the curl and a side portion of the curl engaging member.
The curl engaging member can be a lip that holds the cover to the container by residing in the concave portion below the curl of the container, or a concave portion in which the curl of the container resides when the cover and the container are joined together. Preferably, the curl engaging member is a lip.
The cover of the present invention is either a cover having two concentric cylinders, an inner cylinder and an outer cylinder, or is a cover with a single outer cylinder. In either case, the curl engaging member is affixed inside the cover and engages the curl to hold the cover onto the container during normal operation.
In order to remove the cover from the container in accordance with the present invention, the cover has a press point that is pushed by the user to cause the cover to form an elliptical shape. The press point is positioned on the outside of the cover.
The curl engaging member is not a circle but is discontinuous, such that it has at least two circumferential ends. Preferably, the curl engaging member has two circumferential ends. These circumferential ends define one or more openings in the curl engaging member. At least one of the openings is positioned opposite the press point.
When the press point is pressed and the cover forms an elliptical shape, the side portion of the curl engaging member becomes disengaged from the curl and the circumferential ends are designed to slide easily over the curl because they have a low degree of engagement with the curl. The side portion of the curl engaging member is generally that portion of the curl engaging member that extends from one circumferential end to the other circumferential end. In the case where there are only two circumferential ends and the curl engaging member takes on the shape of the letter “C”, then the side portions of the curl engaging member correspond to the top and bottom of the “C”. The back portion of the curl engaging member is that portion which corresponds to the back of the “C” and directly opposite the opening of the “C”. In the case where there are four circumferential ends, the back of the curl engaging member is absent. As mentioned above, the front of the “C” faces the press point in the cover.
The side portion of the curl engaging member has a higher degree of engagement with the curl of the container than the circumferential ends and accounts for the majority of the curl engaging member.
There are a number of ways in which to make the circumferential ends of the curl engaging member have a degree of engagement with the curl that is less than the side portion degree of engagement with the curl. The ways to make the degree of engagement less include: (1) the circumferential ends of the curl engaging member have a radius of curvature that is greater than the radius of curvature of their side portion; or (2) the elasticity (stiffness) of the circumferential ends is lower than the side portion of the curl engaging member; or (3) the frictional coefficient between the circumferential ends and the curl is less than the coefficient of friction between the curl and the side portion of the curl engaging member.
Preferably, the radius of curvature of the circumferential ends of the curl engaging member is greater than the radius of curvature of the side portion. When the curl engaging member is a lip, the top of the circumferential end has a radius of curvature which is greater than the radius of curvature of the top of the side portion of the lip. When the curl engaging member is a concave portion in which the curl resides, the bottom of the circumferential ends have a radius of curvature that is more than the radius of curvature of the bottom of the side portion of the concave portion.
Preferably, a shoulder is formed on the inside of the cover at a point which is opposite the opening formed by the circumferential ends. Preferably, the shoulder is positioned directly opposite the press point. The shoulder contacts the sloping wall section of the container when the user pushes the press point. As the user presses the press point, the shoulder contacts the upwardly sloping wall of the metal container and causes the cover to rise upwardly in response to the pressing of the user. This guides the cover up and off of the container.
Usually there is a space between the end of the cylindrical portion that the shoulder is formed on and the container. This means that there is a short lag time between when the pressure is applied to the press point and the time that pressure is exerted by the shoulder on the sloping side wall of the con
Kanoya Katsuhiko
Okada Hideo
Bierman, Muserlian and Lucas
Eloshway Niki M.
Mitani Valve Co.
Shoap Allan N.
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