U.S. patent number 3,557,985 [Application Number 04/829,346] was granted by the patent office on 1971-01-26 for tamper-proof plastic closure cap and method of making same.
Invention is credited to Andrew Raoul St. Denis, Marcel Louis St. Denis.
United States Patent |
3,557,985 |
St. Denis , et al. |
January 26, 1971 |
TAMPER-PROOF PLASTIC CLOSURE CAP AND METHOD OF MAKING SAME
Abstract
A two-piece closure cap for self-locking tamperproof containers
consisting of (a) a resilient molded plastic cylindrical part
having an integrally formed resilient ring member extending
inwardly from the interior cylindrical surface and a plurality of
integrally formed radially inwardly extending lugs spaced around
the interior cylinder surface below the ring member and (b) a
separate top closure for the cap consisting of a disc which fits
into an annular recess in the interior cylindrical surface of the
cylindrical part.
Inventors: |
St. Denis; Marcel Louis
(Windsor, Ontario, CA), St. Denis; Andrew Raoul
(Windsor, Ontario, CA) |
Family
ID: |
25254263 |
Appl.
No.: |
04/829,346 |
Filed: |
June 2, 1969 |
Current U.S.
Class: |
215/222 |
Current CPC
Class: |
B65D
41/06 (20130101) |
Current International
Class: |
B65D
41/06 (20060101); B65D 41/04 (20060101); A61j
001/00 (); B65d 055/02 () |
Field of
Search: |
;215/9,44 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hall; George T.
Claims
We claim:
1. A closure cap comprising a molded plastic cylindrical member
having an integrally formed resilient ring member extending
inwardly from the interior cylindrical surface thereof, said ring
member being adapted to engage the mouth of a container, and a
plurality of integrally formed radially inwardly extending lugs
spaced around the interior cylindrical surface below the ring
member, said lugs being adapted to engage notches on the upper end
of the container, and a disc member which closes the upper end of
the cylindrical member.
2. A closure cap according to claim 1 wherein the disc member fits
into an annular recess in the interior cylindrical surface of the
cylindrical member.
3. A closure cap according to claim 1 wherein the disc member is
made from plastic, metal or cardboard.
4. A closure cap according to claim 1, wherein the cylindrical
member is molded from a polyolefin.
5. A method of manufacturing a closure cap which comprises molding
from a resilient plastic a cylindrical member having an integrally
formed resilient ring member extending inwardly from the interior
cylindrical surface thereof and a plurality of integrally formed
radially inwardly extending lugs spaced around the interior
cylindrical surface below the ring member, separately forming a
disc member from a rigid material and pressing the disc member into
the top of the cylindrical member.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a closure for self-locking tamper proof
containers.
2. Description of the Prior Art
For many years there has been a great need for some type of tamper
proof closure for pill bottles, which is simple to construct and
easy for an adult to open, but difficult for a child to open. Many
different types of safety caps have been proposed, but these have
all been either too expensive or difficult to manufacture, or too
difficult to use, or simply not sufficiently safe in the hands of a
child.
The type of closure cap for tamper proof containers which has
received widest acceptance is provided with a spring member which
causes locking elements on the cap to engage retaining slots on the
neck of a tubular container in such a manner that the cap cannot be
removed by mere rotation. Before the cap can be rotated and removed
it is necessary to push the cap down against the tension of the
spring member in order to disengage the locking members. After the
locking members are disengaged the cap may be freely rotated and
removed from the mouth of the container.
The vial described in Nichols, U.S. Pat. No. 3,072,276, issued Jan.
8, 1963, comes close to meeting the requirements for a tamperproof
closure. However, the free floating spring member which is snapped
in past the locking elements in the skirt of the cap does not
provide a uniformly positive spring loading on the locking
elements. This means that even when the correct technique is used,
difficulties can be encountered in removing the cap and this makes
the cap unacceptable to the ordinary consumer.
Attempts have also been made to produce unitary caps in which the
spring member is integrally molded with the cap. An example of such
a cap is that described in Hedgewick, U.S. Pat. No. 3,344,942
issued Oct. 3, 1967 . However, unitary caps of this type present
great difficulties in manufacturing particularly in removing the
molded cap from the die without damaging the spring member. The
Hedgewick patent represents an attempt to overcome this problem by
making the spring member in the form of a thin annular web
extending downwardly and outwardly from the inner face of the top
of the cap. This thin annular web is limited in thickness to permit
removal from the die, which means that it is limited thereby in the
degree of spring loading it can provide against the locking
elements. Moreover, there is a tendency for the thin annular web to
tear when being removed from the die, with the result that a rather
large number of caps must be rejected. This also means that there
is the added manufacturing expense of inspecting the caps for
damaged spring members.
It is the object of this invention to overcome the above
difficulties and provide a tamperproof cap closure which gives
controlled spring loading against the locking elements and is
simple and inexpensive to manufacture.
SUMMARY OF THE INVENTION
According to our invention, we have produced a two-part cap meeting
the above requirements. One part comprises a molded plastic
cylindrical member having an integrally formed resilient ring
member extending inwardly from the interior cylindrical surface
thereof and also a plurality of integrally formed radially inwardly
extending lugs spaced around the interior cylindrical surface below
the spring member. The second part comprises a disc member which
closes the upper end of the cylindrical member.
This cap is adapted for use with the usual tamperproof type
cylindrical container having latching surfaces adapted to engage
and hold the lugs against the axial force of the resilient ring
member in the cap. The latching surfaces are usually either in the
form of grooves recessed into the wall of the container or in the
form of surfaces on radially projecting lugs. Preferably, the
latching surfaces are provided with an abutment or shoulder at one
end which permits the cap to be removed from the bottle by turning
in only one direction.
The cylindrical portion of the cap is molded from a resilient
plastic, such as polyolefin, e.g. polyethylene or polypropylene,
while the disc can be manufactured from practically any rigid
material, including plastics, metal, cardboard etc. According to a
preferred feature, the upper portion of the cylindrical member is
provided with an annual recess into which the disc is pressed. The
disc member can also be provided with an annual projection which is
adapted to control the axial movement of the spring members.
The cap of our invention has important advantages over the
previously known caps.
1. By making the cylindrical member separately, a two-piece mold
die can be used. This means that the spring member can be molded in
the exact shape and thickness that is desired for the final product
and the two die pieces are removed from above and below the spring
member without disturbing the spring member in any way. The result
is that every cylindrical member is perfectly formed so that there
are no production losses from damaged spring members and no
inspection is required.
2. The separate formation of the disc also had advantages in that
it can be formed from a very inexpensive material. Moreover the
discs can be customized to the desires of individual distributions.
In other words, they can be made in different colors and can be
made with the name of the distributor embossed thereon. Because of
their extremely low cost, they can be made in very large numbers
and when a customer order is received the cylindrical members and
discs can be assembled in an automatic capping device.
BRIEF DESCRIPTION OF THE DRAWINGS
Our invention is illustrated by the preferred embodiments shown in
the accompanying drawings, in which:
FIG. 1 is a sectional view of the cylindrical member;
FIG. 2 is a fragmentary sectional perspective view of the
cylindrical member;
FIG. 3 is an elevation view of a container, partly in section,
showing the cap locked on the container;
FIG. 4 is a top plan view of the disc member;
FIG. 5 is a bottom plan view of the disc member, and
FIG. 6 is a transverse sectional view of a mold, showing the manner
in which the cap of the invention is made.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIGS. 1--3, the cap of the invention comprises an open
ended cylindrical skirt 1 having a plurality of radially inwardly
projecting lugs 2 adjacent the lower end thereof. An integral
resilient annular member 3 extends generally radially inwardly from
the skirt 1.
The disc 5, as shown in FIGS. 4 and 5, is of a size which can be
press fitted into the annular recess 4 adjacent the upper end of
the skirt 1. Preferably the disc is provided with a peripheral
projection 6 which fits snugly into the annular recess 4 and is
also provided with an integral annual rib 7 which extends axially
from the surface thereof and is adapted to generally overlie the
free end of the resilient annular member 3.
The container 9 is generally cylindrical and is provided at the
upper end with a plurality of outwardly extending radial
projections 10. As shown in FIG. 3, each radial projection 10 has a
smoothly curved portion 11, a notch or recess 12 and an abutment
13.
When the cap is to be attached to the container, it is placed over
the open end of the container and turned until the lugs 2 engage
the curved portions 11, and the turning motion is continued until
the lugs 2 slip into the notches 12 where they are firmly held
against the axial spring force of the resilient ring member 3.
In order to remove the cap, an axial force must be applied to the
top of the cap sufficient to depress the lugs 2 from engagement
with the notches 12 and then turned in a direction away from the
abutments 13. The annular rib 7 is adapted to engage the resilient
ring member 3 when the cap is depressed and prevent the lugs 2 from
being depressed below the lower faces of the abutments 13.
The caps of this invention can be provided with a very strong
springing action in the resilient ring member 3. Since the cap can
only be removed by a uniformly applied strong downward push to free
all of the lugs 2 from the engaging notches 12, combined with a
turn in the proper direction, it will be evident that it would be
most unlikely that a child could ever accidentally remove the
cap.
FIG. 6 shows the appearance of the molded cylindrical member as it
is formed in a mold having an upper element 15 and a lower element
16. A plurality of pin members 17 are provided having their lower
ends extending downwardly into the cavity that defines the
cylindrical wall. The lower ends of the pin members 17 define the
upper surfaces of the lugs 2. The openings 8 in the ring member 3
are caused by the pin members 17 passing through the portion of the
mold cavity forming the ring member.
In operation, plastic is introduced under pressure into the mold
cavity. Then, the mold elements are drawn apart leaving the molded
article. Since the mold elements 15 and 16 part in the region of
the resilient ring member 3, it will be seen that the entire
cylindrical member can be removed from the mold elements without
deformation. This means that the thickness of the resilient ring
member 3 can be varied as desired without any difficulties in
removing the molded product from the mold.
* * * * *