Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
52(~
DOUB~JE-SEAL, MOLD~D PLASTIC SCREW CAP
~his invention relates to plastic screw caps Eor
use with small hand held containers, such as are provid-
ed to hold and dispense cosmetic products. More particu-
larly, the invention relates to such caps wherein a pl~
urality of seals is provided to insure the preservation
of the cosmetic product during shipping and storage,
extended shelf life, etc.
In the past various t~pes of plastic screw caps
having multiple seals have been proposed and produced.
Some of these prior screw caps have involved deformable
depending skirts or flangesr whereas others have in-
volved plug formations insertable in the neck of the
cooperable container. The prior caps have in most cases
not only involved complicated mold forms which were ex-
pensive, but also required the use of a substantial
amount of plastic material in order to effect the de-
sired double sealing function. Thus, there was entailed
a considerable mold cost and in addition the unit cost
per cap was not inconsequential, particularly since the
cost of the plastic molding material has now become a
factor due to increasing petroleum costsO
Moreover, in many instances, the configuration of
the cap did not insure the preservation of the seals if
the plastic material thereof deformed by reason of
shrinkaye, or adverse environmental ~actors.
The above disadvantages and drawbacks of prior
molded plastic screw caps are obviated by the present
invention which provides a double-seal molded plastic
screw cap for use with a threaded-neck container of the
type intended to hold a solid cosmetic product having a
~ `32 ~ ~
volatile ingredient, said screw cap comprising, in com-
bination a resilient cup-shaped plastic cap body having
an annular side wall integral with a transverse top
wall, said side wall having internal screw threads
adapted for engagement with the external screw threads
of the container neck, said side wall oE the cap body
having an annular sealing surface disposed above the
internal screw threads and between the latter and the
top wall, said sealing surface being slidingly and tele-
scopically engageable with the outer annular surface ofthe container neck at the top rim thereof, to provide a
first seal therewith, said annular side wall of the cap
body having a perfectly flat downwardly-directed annular
sealing surface on its bottom edge for abutting engage-
ment with a cooperable sboulder of the container neck to
provide a second seal therewith, said annular sealing
surfaces of the cap being spaced apart a distance equal
to the spacing of the outer annular surface and cooper-
able shoulder of saicl container, thereby to effect si-
2~ multaneous seals therewith, the annular side wall of the~ap extending upward ~o said top wall past the annular
sealing surface therein; so as to provide a clearance
chamber in which a portion of said cosmetic product can
extend and be disposed.
Other features and advantages will hereinafter ap-
pear.
In the accompanying drawings:
Fig. 1 is an axial view showing the cap in axial
section and the cooperable container in side elevation,
with the cap in its double-seal position on the con-
tainerO
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Fig. 2 is an exploded view showing the cap in axial
section, removed from the container which latter is in
side elevation.
Fig. 3 is a fragmentary sectional view, enlarged,
of the double seal structure adjoining the screw
threads.
Fig. 4 is a view like Fig. 3, but showing the
single seal of the prior art, and
Fig. ~ is a view partly in axial section and partly
in side elevation, of a cap and container representing
prior art.
As shown, the screw cap is designated by the nu-
meral 10, being adapted for use with a container 11 of
generally conventional configuration.
The container 11 has a body portion 12 and a neck
portion 14, the latter being provided with a usual type
of external screw thread 16. Between the neck portion 14
and the body portion 12, the container has an exterior
annular shoulder 18 which is accurately formed to lie in
a perfectly flat plane. Above the screw threads 16 the
neck portion 14 of the container has an annular, exter-
ior, smooth sealing surface 20 located at the top rim or
edge 22.
The exterior shoulder 18 and the sealing surface 20
of the container 11 are intended to cooperabe with mat-
ing surfaces or portions of the screw cap 10 to effect a
reliable double seal.
The container 11 can carry a solid cosmetic product
such a deodorant stick ~5 which normally protrudes from
the neck portion 14 as shown.
The screw cap 10 is formed in a unique manner to
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provic!e a firstl sliding seal engageable with the sur-
face 20 of the neck 14 and which is independent of pre-
cise axial positioning of the cap, and a second seal
cooperable with the shoulder 18 of the container to pro-
vide a second seal which depends on the screw cap 10
being tightly screwed onto the container.
Also, the screw cap 10 has a clearance chamber 24
above the screw threads and under its transverse top
wall 26 to accommodate a portion of the cosmetic product
25, such chamber being characterized by especially thin
walls to effect a saving in the material that is re-
quired in molding.
The screw cap 10 comprises an annular side wall 28
which is integral with the top wall 26 and which has
internal screw threads 30 for engagement with the exter-
nal threads 16 of the container neck 14~
The side wall 28 of the cap body has an annular
sealing surface comprising an inwardly raised annular
bead 32 which is located above the internal screw
threads 30 and between the latter and the top wall 26.
The sealing surface or bead 32 is slidingly and teles-
copically engageable with the outer annular surface 20
of the container neck adjacent the top rim 22 thereof,
to provide a first seal which is independent of the pre-
cise axial positioning of the cap.
The annular side wall 28 of the cap body has a per-
fectly flat, downwardly-directed annular sealing sur~ace
34 on its bottom edge, for abutting engagement with the
cooperable shoulder 18 of the container neck to provide
a second seal therewith~
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The annular surfaces 32 and 34 of the cap are
spaced apart a distance equal to the spacing of the an-
nular surface 20 and shoulder 13 of the container,
thereby to effect simultaneous seals therewith. The an-
nular side wall of the cap, where it is designated 36,
extends upward to the top wall 26 from the annular seal-
ing surface 32 so as to provide the clearance chamber
24, in which a portion of the cosmetic product 25 is
disposed. The walls of the clearance chamber 24 can be
especially thin whereby the inside diameter in the cham-
ber 24 is greater than the inside diameter of the seal-
ing bead 32. That is, the wall ~hickness of the bead 32
is greater than the wall thickness of the chamber 24
whereby an appreciable saving of plastic material is
had.
It will be noted that if the plastic material of
the screw cap should shrink slightly to reduce the cap
diameter, this will cause the sealing bead 32 to more
snugly engage the cooperable sealing surface 20 of the
container neck. Thus, the seal at such point is not ad-
versely affected.
A polypropylene plastic formulation has been found
to be satisfactory for use in molding the present cap,
since it has the desired resilience and stiffness, and
enables the cap to be readily stripped from the mold
without requiring an unscrewing movement.
Figure 5 shows a cap and container according to the
prior art. The cap is molded of rigid plastic, and has a
sealing shoulder 40 which is abuttingly engageable and
sealable with the top surface of the rim of the contain~
er neck 44. The seal depends on the cap being screwed
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down tightly, and is no-t effective for slightly differ-
ent axial positions of the cap on the container as with
the present constructionO
The applicant's cap construction can be produced in
especially simple, economical-to-fabricate molds while
still insuring the preservation of the double seal under
various conditions of use.
Also, a minimum quantity of plastic material is
required, thus reducing the unit cost to the greatest
possible extent.
As noted above, the screw cap is especially reli-
able for the intended use in spite of the possibility of
slight deformation or shrinkage occurring in the plastic
substance. Moreover the use of the screw ca does not
require alteration or extensive modification of the co-
operable container neckn
Variations and modifications are possible without
departing from the spirit of the invention.
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