U.S. patent number 3,707,241 [Application Number 05/030,517] was granted by the patent office on 1972-12-26 for plasitc container with threaded mouth strengthening closure means.
This patent grant is currently assigned to Sanford Research Company. Invention is credited to Guy A. Taylor.
United States Patent |
3,707,241 |
Taylor |
December 26, 1972 |
PLASITC CONTAINER WITH THREADED MOUTH STRENGTHENING CLOSURE
MEANS
Abstract
A blow molded plastic container such as a bottle or a jar having
a threaded thin walled mouth portion is provided with an internally
threaded closure and a reinforcing means for strengthening and
backing the mouth portion of the container. The reinforcing means
in said closure includes an insert or backing member which can have
a tapered or frusto-conical outer surface for backing or
strengthening the mouth portion of the bottle or jar adjacent the
lip when the closure is screwed over the bottle or jar mouth. The
insert or backing member can be an integral part of the closure.
Alternatively the insert or backing member can be part of a disc
insert for the closure, the backing member being a downwardly
extending circular flange. In either event the backing member is
spaced inwardly from the closure threads a proper distance to
tightly receive the threaded mouth wall between the backing member
and the closure threads against accidental dislodgement. The
closure can also be provided with a surface for engaging the lip of
the mouth of the jar for sealing the jar.
Inventors: |
Taylor; Guy A. (Batavia,
IL) |
Assignee: |
Sanford Research Company
(N/A)
|
Family
ID: |
21854583 |
Appl.
No.: |
05/030,517 |
Filed: |
April 21, 1970 |
Current U.S.
Class: |
215/337; 215/42;
215/44; 215/354; 220/288 |
Current CPC
Class: |
B65D
41/0435 (20130101); B65D 41/0414 (20130101); B65D
41/28 (20130101) |
Current International
Class: |
B65D
41/28 (20060101); B65D 41/04 (20060101); B65D
41/02 (20060101); B65d 041/04 () |
Field of
Search: |
;215/43A,43R,1C,31,48,41
;150/.5,8 ;220/39,42C |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
542,508 |
|
Nov 1955 |
|
BE |
|
1,327,731 |
|
Apr 1963 |
|
FR |
|
1,149,828 |
|
Jul 1957 |
|
FR |
|
Primary Examiner: Wood, Jr.; M. Henson
Assistant Examiner: Culp, Jr.; Thomas C.
Claims
I claim:
1. A container and closure combination in which the container has a
thin walled round hollow-threaded mouth portion with generally
uniform wall thickness throughout the threaded portion, closure
means having internal threads sized for threading onto the threaded
mouth of the container and means carried by said closure means for
reinforcing the threads on the mouth of the container to prevent
collapsing of said threads during application of said closure and
during deformation of said container upon impact.
2. The combination of claim 1 wherein said reinforcing means
comprises means backing the container mouth wall at the inner
surface thereof for backing the mouth wall against radial inward
movement and dislodgement of the mouth threads from the closure
threads due to impact or over-tightening of the closure.
3. The combination of claim 2 wherein said reinforcing means
comprises means contained within said closure means.
4. The combination of claim 2 wherein said reinforcing means
comprises means defining a cylindrical surface within the closure
spaced inwardly from the closure threads a proper distance to
receive the mouth wall between the cylindrical surface and the
closure threads.
5. The combination of claim 2 wherein said reinforcing means
comprises means defining a frusto-conical surface within the
closure spaced inwardly from the closure threads a proper distance
to receive the mouth wall between the frusto-conical surface and
the lid threads, a portion of said frusto-conical surface wedging
the mouth wall outwardly and tightly within the closure threads as
the closure is threaded onto the mouth.
6. The combination of claim 2 wherein said reinforcing means
comprises a cylindrical flange depending from the top wall of said
closure means and spaced radially inwardly from said closure
threads a distance sufficient to tightly receive the container
mouth wall therebetween.
7. The combination of claim 6 wherein said reinforcing means
includes a resilient plastic circular disk insert resting in said
closure and lying against the closure top surface and being
integral with said cylindrical flange at the top edge of said
flange.
8. The combination of claim 6 wherein said closure and cylindrical
flange are an integral one-piece molded resilient plastic
member.
9. A closure for a blow molded container having a thin wall
relatively flexible externally threaded round mouth having a lip
portion, said closure comprising a circular shaped central portion,
with a cylindrically shaped downwardly depending wall portion
having internal threads of matching configuration to the external
threads on the container mouth, and a cylindrically shaped
depending flange spaced inwardly from said depending wall for
receiving the threaded mouth wall between said depending flange and
said depending wall, said depending flange being inserted into the
open end of said container with the outer wall of said depending
flange being positioned in thread backing relationship with respect
to said threads, and said depending wall surrounding said mouth
wall and being threaded onto the threads of said mouth wall,
whereby the compressive forces of the threads of said closure
against the thread of said mouth wall will compress the mouth wall
of the container inwardly against the depending flange with the
circular central portion of the closure seated against the lip
portion of the mouth whereby the container is sealed and accidental
disengagement of the closure from the container by impact is
prevented.
10. The closure of claim 9 wherein said depending flange is formed
integral with and depends from the circular central portion of the
closure.
11. The closure of claim 9 wherein said depending flange is
integral with and depends from a disk insert received within said
closure with the upper surface of the disk seating against and
generally co-extensive with a portion of the lower surface of the
circular central portion of the closure.
12. The closure of claim 9 wherein said depending flange has an
inwardly downwardly tapered frusto-conical outer surface for
wedging and sealing against the inner surface of the mouth as the
closure is threaded onto the container.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to reinforcing means for the threaded mouth
portions of thin walled plastic containers and in particular to
closure devices having backing members for reinforcing the threaded
thin wall portion at the open part of a thin walled container.
2. Description of the Prior Art
Available blow molded plastic containers, such as bottles or jars,
usually have a mouth portion with hollow threads for receiving a
closure. However such containers have been deficient in that the
threads are not strong enough to withstand forces normally
encountered in use of the container. The hollow threads are of
necessity quite wide and the mouth wall is usually quite thin
because of the requirement of blow molding and usually the
container will have only a single spiral (360.degree.) thread
around the neck. Such threads are not adequate to withstand
excessive twisting or shock forces transmitted to the mouth through
impact. Excessive twisting easily overtorques the hollow threads
and can cam the container mouth wall inwardly permitting leakage or
spillage, and in some cases can even destroy the container wall at
the threads. Dropping the container often collapses the neck
portion of the container, dislodging the closure from the threads,
again causing spillage.
The known prior art related to the use of caps or closures for
glass or metal containers wherein the caps or closures are provided
with inserts which project down into the open mouth of the
containers for sealing purposes only. None of the prior art
attempted to use the insert to back or reinforce the threads of the
thin wall of a blow molded container.
SUMMARY OF THE INVENTION
The present invention provides a reinforcement for a thin walled
hollow threaded mouth portion of a flexible container. The
reinforcement for an internally threaded closure having threads
cooperating with the thin walled threads of the container and
having a system for holding the upper edge portion of the container
threads spreading outwardly against dislodgement from the threads
of the closure. While this invention is susceptible of embodiment
in many different forms there are shown in the drawings and will
herein be described in detail certain forms of the invention and
modifications thereof with the understanding that the present
disclosure is to considered as an exemplification of the principles
of the invention and is not intended to limit the invention to the
forms and modifications illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary side view of a plastic container closed by
one form of a closure of this invention;
FIG. 2 is a fragmentary perspective view of the closure exploded
from the top of the container (of FIG. 1);
FIG. 3 is an enlarged partial section through the mouth portion of
the container of FIGS. 1 and 2 and an insert portion of the closure
showing the insert entering the mouth of the container;
FIG. 4 is an enlarged partial section as in FIG. 3 showing the
insert in a position sealing the lip of the container;
FIG. 5 is an enlarged partial section as in FIG. 4 but showing the
remainder of the closure in position closing and sealing the mouth
of the container;
FIG. 6 is an enlarged partial section as in FIG. 4 through the
container mouth showing another form of the insert;
FIG. 7 is an enlarged partial section as in FIG. 6 but including
the remainder of the closure in position closing and sealing the
mouth of the container; and
FIG. 8 is an enlarged partial section through a mouth portion of
the container showing still another form of closure in position
closing and sealing the container.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the preferred forms the reinforcing means which retains the
threads of the container mouth and closure in engagement against
stresses of impact shock and which prevents over-tightening of the
closure is a backing member which backs the container mouth wall at
the inner surface thereof and reinforces the mouth wall against
radial inward movement which may otherwise permit dislodgement of
the mouth wall from the lid threads. In one preferred form, the
backing member defines a restricted entry channel for the container
mouth wall to support the mouth wall between the closure threads
and the backing member so that the wall cannot be cammed inwardly
by over-tightening of the closure. The backing means is contained
within the closure and defines a cylindrical or frusto-conical
surface spaced inwardly from the closure threads a proper distance
to receive the mouth wall between the cylindrical or frusto-conical
surface and the closure threads. In another preferred form the
backing member is a circular flange depending downwardly within the
closure.
Referring to FIGS. 1 through 5 there is illustrated a plastic
container having a body portion 12 and an externally threaded
cylindrical thin walled mouth portion 14 terminating in an axially
facing lip 16. The container is formed by blow molding resilient
plastic material such as polyethylene, polypropylene and the like
and has generally uniform wall thickness throughout the body
portion 12 and the threaded mouth portion 14. The mouth portion 14
has a molded helical indentation 18 formed in the inner surface of
the neck of the container which forms the inner back surface of the
external thread 19, defining a spiral or helical thread commonly
known as a "hollow" thread which does not have any extra thickness
in the mouth portion and, therefore, the thread does not materially
strengthen said mouth portion. Such uniform wall thickness
throughout the body portion and threaded mouth portion of a
container is conventional in blow molded plastic jars.
The closure for the container includes a stamped or otherwise
formed sheet metal lid 20 having a top wall 22 and an internally
threaded circular or cylindrical depending wall 24 with internal
threads 25 formed in said wall 24. The threads 25 are properly
sized for receiving the external thread 19 of the mouth portion 14
of the container. An insert or backing member 26 which in the
illustrated form is a resilient plastic molded part, is provided in
the closure 20 with disc portion 27 having an upper surface 28
being flat for lying against the inner surface of top wall 22 of
the closure. The diameter of the disc 27 is generally coextensive
with the bottom or inner surface of top wall 22 and is preferably
at least slightly larger than the smallest internal diameter of the
internally threaded wall 24 of the closure 20 so that the disc
insert 26 does not freely fall from within closure 20. The insert
26 includes a depending flange 29 having an exterior surface spaced
inwardly slightly from the outer edge of disc portion 27. The
flange 29 has a two portion outer surface 30, one portion being a
circular cylindrical surface 31 which joins with the disc 27
thereby forming an overhanging lip sealing surface 32 on the disc
27 extending peripherally of the flange 29. The second portion of
the surface 30 is a tapered outer surface 33 which merges at its
largest diameter with the cylindrical surface 31.
With particular reference to FIGS. 3-5, it will be seen that insert
or backing member 26 can be inserted via flange 29 in the open
mouth of container 12 (FIG. 3) with the tapered surface 33 engaging
with the inner surface of the lip 16 of the mouth 14 of the
container 12. As the insert 26 is driven downward within the mouth
of the container 12 the tapered outer surface 33 cams against the
inner surface of mouth 14 to urge the lip portion 16 of the mouth
14 radially outwardly until the cylindrical surface 31 rests in the
mouth 14 for backing and reinforcing said lip portion and mouth of
the container. The over-hanging lip sealing surface 32 of the
insert rests against the axial lip 16 of the mouth of the container
to provide an axial backing also. With the insert 26 positioned
within mouth 14, the closure 20 is threaded onto the thread 19 on
the mouth of the container 12 to the position shown in FIG. 5. The
insert 26 in the mouth portion of the container 12 reinforces and
rigidifies the thread 19 and the mouth portion 14. The threads 25
of the wall 24 of the closure create an inward compressive force on
the threads 19 of the container, but the flange 29 of the insert 26
prevents the lip and threads 19 of the mouth 14 of the container
from collapsing and releasing the sealing of the container. The
clamping of the wall of mouth 14 between the flange 29 and the wall
24 of the closure not only provides the threaded connection with
the ability to resist inward movement of the wall of the mouth due
to over-tightening of the closure, but also provides the threaded
connection with the ability to prevent dislodgement of the closure
during the shock deformation created by dropping the sealed
container.
The embodiment of FIGS. 3-5 employs one of the optimum conditions
wherein the insert flange is shaped to hold the upper edge portion
of the mouth of the container in outwardly spread position. In this
way the upper edge portion can not collapse. This embodiment as
well as the later described embodiments provide a structure which
can be used very effectively in automatic capping equipment where
the containers are automatically filled and the container is then
capped by means of an automatic capping machine. Such capping
equipment can easily over-tighten and strip the threads on a
container but with the new reinforcing insert of the invention caps
are readily applied without stripping or other failures.
One of the frequent uses of containers of this type is for paste
for use in schools. The containers are frequently dropped which
heretofore generally resulted in the mouth of the container
collapsing, permitting the cap to pop off or loosen. The contents
were either spilled or dried out as a result of the seal being
broken. With the new reinforcing insert, the threads of the
container are backed and the closure is positively sealed thereon
preventing dislodgement due to over-tightening or due to the shock
distortion caused by dropping or administering a sharp blow to the
container.
Once the closure is tightened on the mouth of the container the lip
16 of mouth portion 14 engages the lip sealing surface 32 of the
insert 26 to further seal the jar against leakage. The abutment of
lip surface 16 of the container against surface 32 of the insert
with the backing flange 26 in position produces an axial
compressive force between the threads and the disc portion of the
insert 26 which when combined with the radial reinforcement created
by the flange 29 effectively locks the closure on the container
without fear of collapsing the threads of the container by
over-tightening or without fear of accidental dislodgement caused
by dropping the sealed container.
The form of insert or backing member 26 shown in FIGS. 6 and 7 is
the same as that in FIGS. 3-5 except that the tapered surface 30 on
the exterior surface of the flange 29 is replaced by a cylindrical
surface 30a. It has been found that even with the cylindrical
surface 30a sufficient reinforcing of the mouth portion 14 of the
container 12 between flange 29 and wall 24 is achieved. That is,
the cylindrical surface 30a on the flange 29 has an outside radial
dimension fairly matching the inside dimension of the mouth 14 of
the container. The only limitation being that the spacing between
the inside diameter of the mouth of the container and the outside
diameter of the cylindrical surface 30a of the insert should be
less than the radial height of the thread on the mouth of the
container such that with the insert 26 in position in the container
and with the closure threaded down onto the mouth of the container
as the lip 16 bears against the lip 32 and the mouth of the
container is cammed radially inward under the radial compressive
forces of the threads 25, the inner surface of the mouth will
engage with the flange of the insert and prevent the mouth and
thread from collapsing the insert will reinforce and back the mouth
of the container to prevent dislodgement and disengagement of the
closure from the container.
Turning now to FIG. 8, the closure illustrated is a one-piece
integral molded resilient plastic member and includes a top wall
40, an outer interiorly threaded flange 42 and an inner flange 44
which has an outer two portion tapered surface 46 and 47 and a lip
sealing surface 48. It will be apparent that the closure shown in
FIG. 8 operates in the same manner as that shown in FIGS. 3-5 and
gives the same reinforcing action to strengthen the threaded
connection when the closure is threaded onto the top of the
container.
It has been found that the integral concept of FIG. 8 has
particular practical application in smaller containers and closures
where the closure and insert can be readily molded in one piece.
For larger sizes it becomes uneconomical or less practical to mold
the closure and insert together and in that case they are made
separate and assembled prior to use. When made separate the
material of the closure and insert can be different.
It is to be understood that closures having a spout or other
opening formed in the flat disc portion which spout or opening
would register with an opening in the flat wall of the insert would
be within the context of this invention. Likewise, although the
description is directed toward plastic containers it is within the
invention to use the reinforcing insert concept on any container
having thin walled threaded portions or readily collapsible
threaded portions. Many other applications of the principle of this
invention will become apparent after the concept is understood in
the art and it is contemplated that these applications will be
within the scope of the invention as claimed.
* * * * *