U.S. patent number 3,837,519 [Application Number 05/324,083] was granted by the patent office on 1974-09-24 for container closure with opening indicators.
Invention is credited to Walter Merton Perry.
United States Patent |
3,837,519 |
Perry |
September 24, 1974 |
CONTAINER CLOSURE WITH OPENING INDICATORS
Abstract
A tamper indicating closure for containers having a threaded
section below the mouth and an annular locking shoulder below the
threads, in which two or more tamper indicator extensions project
down from the closure main body, and have horizontal cross slots
and vertical score lines and their lower edges hooked to the
locking shoulder, and such that the score lines rupture when the
closure is removed. Score lines may be notched at the ends to
provide rounded corners and projecting bosses shield the sharp
edges. Alternative design comprises complete circle of rectangular
segments below a ring of horizontal slots, and with the segments
defined by vertical score lines extending from the lower edge up to
bisect the wall material between adjacent slots, thus providing
firm anchorage of upper corners of all segments after rupture of
score lines. The preformed cup for the closure, prior to threading,
is made with spaced depressions around the cylindrical side wall to
provide concentric alignment of closure top panel and gasket on
mouth during sealing and threading. Alternatively depression in top
panel provides improved centering. Advantages of closure include
less material and lower cost, more positive tamper indication,
impossible to restore after tampering, free of sharp corners and
sharp edges that cut fingers. A torquing mechanism is provided in
the bottling line to insure uniform removal torque. Improvements
apply to both pre-threaded and threaded-on-neck types of closures
in ductile metal or plastic.
Inventors: |
Perry; Walter Merton (Darien,
CT) |
Family
ID: |
23261992 |
Appl.
No.: |
05/324,083 |
Filed: |
January 16, 1973 |
Current U.S.
Class: |
215/365 |
Current CPC
Class: |
B65D
41/348 (20130101); B65D 2401/35 (20200501) |
Current International
Class: |
B65D
41/34 (20060101); A61i 001/00 (); B65d
055/02 () |
Field of
Search: |
;215/7,42,46R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hall; George T.
Claims
What I claim is:
1. A tamper indicating container closure made of thin ductile
metal, of the type which embodies fracturable indicator means to
show whether the closure has been removed subsequent to the initial
application of the closure to the container, for use on containers
of the type which has a threaded mouth end and has a downwardly
facing locking shoulder abutment extending around the periphery of
the container neck and positioned below the threaded section and
which comprises means to actuate said indicator means as the
closure is unscrewed, said closure comprising a top panel with
depending cylindrical body, a threaded section in said cylindrical
body to match the threads of said container mouth end, the
improvement comprising;
a plurality of arc shaped segmental indicator members formed as
integral individual downward extensions of said cylindrical body,
the lower edges of said indicator members being turned under said
container locking shoulder at initial application of the closure to
secure a hold on said shoulder, each said indicator member having a
substantially vertical weakening score line formed therein, said
score line extending from the lower edge of said indicator member
to the region just below said threaded section, and whereby
unscrewing of said closure causes rupture along said score line to
provide visual indicator means to show that such closure removal
has taken place.
2. A tamper indicating container closure as defined in claim 1, in
which there is a substantially horizontal slot cut through the
metal of said closure and located in a position just above each
said score line, and such that said score line, or a line drawn as
an upward extension of said score line, intersects said slot, and
there being a separate slot for each score line.
3. A tamper indicating container closure as defined in claim 1, in
which there are two substantially horizontal slots cut through the
metal of said closure for each of said score lines, and with said
slots located at a level in the region of the upper end of said
score line, and with an uncut space between the ends of said slots,
and such that said score line, or a line drawn as an upward
extension of said score line, meets said uncut space and does not
intersect either of said slots.
4. A tamper indicating container closure as defined in claim 1, in
which there is a plurality of substantially vertical weakening
score lines formed in each of said indicator member extensions, and
with each of said score lines being formed as defined in claim 17,
and there being a substantial lateral space between adjacent score
lines.
5. A tamper indicating container closure as defined in claim 4, in
which a plurality of said indicator member extensions each has only
two score lines, and in which there is a substantially horizontal
individual slot cut through the metal of said closure and
positioned at a level in the region of the upper ends of two
adjacent score lines, and above the segmental space between said
two score lines, and having a length that is shorter than the space
between said score lines, and such that said slot is not
intersected by either of said score lines, or by a line drawn as an
upward extension of either said score line.
6. A tamper indicating container closure as defined in claim 4, in
which there are substantially horizontal slots cut through the
metal of said closure in a plurality of said indicator member
extensions, each said slot being positioned at a level in the
region of the upper ends of two adjacent score lines, said slot
having a length that is shorter than the distance between said
adjacent score lines, and such that said slot is not intersected by
either of said score lines, or by a line drawn as an upward
extension of either said score line, and said slot lying above the
space between said score lines.
7. A tamper indicating container closure made of thin ductile
metal, of the type which embodies fracturable indicator means to
show whether the closure has been removed subsequent to the initial
application of the closure to the container, for use on containers
of the type which has a threaded mouth end and has a downwardly
facing locking shoulder abutment extending around the periphery of
the container neck and positioned below the threaded section and
which comprises means to actuate said indicator means as the
closure is unscrewed, said closure comprising a top panel with
depending cylindrical body, a threaded section in said cylindrical
body to match the threads of said container mouth end, the
improvement comprising;
a continuous cylindrical integral member extending below said
threaded section, formed circumferentially around the body of said
closure, and divided into a plurality of rectangular segments, each
segment being defined by a substantially vertical score line at
each end, said score line extending from the lower edge of each
said segment up to the region just below said threaded section, and
each segment having its lower edge turned under said locking
shoulder at initial application of said closure to secure a hold on
said shoulder, and whereby unscrewing of said closure causes
rupture along said score lines, providing visual indicator means to
show that such closure removal has taken place.
8. A tamper indicating container closure as defined in claim 7,
wherein there is a substantially horizontal slot cut through the
metal of said closure and extending along the upper border of each
of a plurality of said rectangular segments, each said slot having
a length that is shorter than the distance between said score
lines, such that said slot is not intersected by either of said
score lines, or by a line drawn as an upward extension of either of
said score lines.
9. A tamper indicating container closure as defined in claim 8,
wherein the length and lateral position of each said slot in said
closure is such that each end of said slot is no closer to the
score line adjacent that end than a distance of 0.04 inch.
10. A tamper indicating container closure as defined in claim 7,
wherein the threads in said cylindrical body of said closure are
roll formed during the initial application of said closure to said
container with the closure blank in position on said container
mouth end, and providing means to match the threads formed in said
closure with those in said mouth end.
11. A tamper indicating container closure as defined in claim 7,
wherein the said thin ductile metal is hard temper aluminum alloy
having a thickness between 0.007 and 0.010 inch.
12. A tamper indicating container closure as defined in claim 7 in
which there are outwardly protruding bulges in the metal of the
closure, said bulges positioned near the sides of a plurality of
said score lines, and comprising protective means to prevent injury
by cutting from the sharp ruptured edges along said score lines
after said closure has been opened.
13. A tamper indicating container closure as defined in claim 7, in
which there are notches in the lower edge of the material of said
segments, said notches being located at the lower ends of said
score lines.
14. A tamper indicating container closure as defined in claim 10,
wherein there is a concentric circular depression in said top panel
of said closure, and said depression having an outer diameter on
the underside which is slightly smaller than the inner bore of said
container mouth end, and providing guidance means for holding said
top panel in concentric alignment on said container mouth end
during the top sealing and thread rolling operations.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the threaded cap type of closure for use
on containers which have a threaded mouth for receiving the
closure. It is most often, but not necessarily, used on containers
having contents which develop internal pressure, as from charged
liquids. Most particularly it relates to such closures which
incorporate visual indicating means to show the user whether or not
the closure has been tampered with, or removed from the container
subsequent to the initial filling and sealing. The indicating means
in this type of closure usually makes use of a locking shoulder
provided on the container neck, and positioned downwardly of and
just beyond the threaded section. It also relates to the class of
closure that can be screwed back on again, such that partial
contents remaining in the container can be resealed for later use
without appreciable loss of pressure.
The greatest field of use of the invention is for the type of
construction in which the closure is drawn into the shape of a cup
from ductile sheet metal material, generally thin hard temper
aluminum alloy, and with the threads of the closure roll formed
after the cup shaped blank is placed on the neck of the container
so the threads match perfectly. It applies also, however, to cup
shaped caps of metal or plastic which are prethreaded before
application to the container. Further, the invention applies
chiefly to the type of closure in which tamper proof indicating
means remains attached to the closure. This leaves the neck of the
container free of a part of the closure, such as the metal band
left on the neck with some types used heretofore. Such bands have
been found difficult to remove when the container is to be
refilled, or the material of the container is to be recycled.
2. Description of Prior Art
There are two commonly used pilferproof screw type closures for use
on threaded neck containers. The first is covered by A. G. Osborne
et al. U.S. Pat. No. 3,303,955, issued Feb. 14, 1967, and comprises
a threaded-in-place closure with a pilferproof band which breaks
off and remains on the neck after opening. The second is shown in
H. R. Kutcher U.S. Pat. No. 3,601,273, issued Aug. 24, 1971, and
teaches a similar threaded-in-place closure, but with a pilferproof
band which has vertical weakening lines around its circumference
which fracture when the closure is removed, but the band remains
attached to the main body of the closure.
In both types the closure is applied in the following way, a
description of which will more clearly show the improvements of my
invention. As described in the Osborne et al. patent, the container
has a threaded section just below a cylindrical sealing shoulder at
the upper end of the container mouth. An annular downward facing
shoulder is provided below the threads, to which the pilferproof
band is locked. The cup shaped cap is usually pre-formed from 0.008
to 0.0095 thick hard temper ductile aluminum alloy sheet. The cap
is made large enough on its inside diameter to fall down freely
over the threads of the container mouth when it is applied at the
entrance of the high speed bottling machine. There is a flat
polyvinyl chloride sealing disc, or gasket, adhesively held inside
the top panel of the closure, and in this construction the diameter
of the disc must be large enough to permit its edges to be formed
down around the end of the container mouth to provide side sealing
around the exterior side cylindrical surface of the mouth.
After the container is filled and the cap positioned on the mouth,
a pressure head comes down and reforms the closure's top panel to a
smaller diameter to provide the side sealing under high pressure.
The pressure head then holds the sealing disc under high end
pressure while thread forming rolls form the threads in the body of
the closure matching those in the container neck underneath. The
tamper indicating means of the Osborne et al. patent comprises a
cylindrical band positioned just below the threaded section, and
attached thereto by a circle of narrow bridges formed by cutting
slots or lances through the metal around the circumference. During
the thread rolling operation another roll turns the lower edge of
the band under the locking shoulder of the neck. When the closure
is unscrewed, the bridges break and the band remains on the neck as
a tamper indicator, and this is objectionable when the container is
to be refilled.
The Kutcher type closure is similar in structure and method of
application to the Osborne, except for the pilferproof band. In the
Kutcher the locking band has a series of vertical weakening lines
formed in the band uniformly spaced around the circumference, and
the band is attached to the body of the closure by a number of very
narrow bridges, spaced by horizontal slots, and positioned at
random relative to the lines of weakening. The lower edge of the
locking band is also turned under the locking shoulder. When the
closure is unscrewed, the turned-under lip of the band rides over
the shoulder, placing the band in tension, and causing rupture at
the weakening lines. Because of the very narrow bridges, the
segments flare outward, some of the bridges break, and the sharp
fractured ends of the segments are exposed, and can cut
fingers.
This closure system has several disadvantages. The most serious one
is that the sharp ends of the segments extend out at varying
distances and tend to cut the fingers when removing or re-applying
the closure. This is shown clearly in FIG. 4 of the drawings in
U.S. Pat. No. 3,601,273. Another disadvantage is that often when
the band is not rolled tightly under the shoulder the lines barely
rupture, and the closure can be screwed back on, the segments
pushed back into place, and the casual observer will not notice
that the container has been opened. Both of these types of closure
vary greatly in the amount of torque required to open them. The
torque varies from 4 inch pounds to 17 inch pounds, and most users
can not exert over 12 inch pounds with their fingers. This is also
indicative of variation in tightness of seal. I find that the main
reason for this large variation is failure to accurately center the
closure sealing disc on the end of the container when the threads
are formed. It is almost always off to one side, and this causes
the PVC sheet to be squeezed thin under very high pressure on one
side of the side seal, while the other side is barely compressed.
This is because the cylindrical body of the cup has to be over-size
to drop freely over the threads of the neck, and the threads are
therefore not effective in aligning the cup. Furthermore the
diameter of the upper outside shoulder of the neck is much smaller
than the threads, and of no use in assisting the alignment.
Accurate alignment must be attained before the pressure head comes
down, and this is part of my invention.
SUMMARY OF THE INVENTION
The primary objective of the invention is to provide a threaded cap
type container closure which has visible tamper indicating means to
show whether the closure has been removed susequent to its initial
application to the container, and to accomplish this without
leaving part of the closure on the container.
Another important objective of the invention is to provide
indicating means that do not present sharp surfaces that can cut
the fingers when the closure is removed or re-applied. Another
object of the invention is to provide indicating means which are
more positively visible than used heretofore, and which can not be
restored after the closure is re-applied.
Another objective of the invention is to reduce the cost of the
closure by using less material for the closure blank, and at the
same time enable its use on high speed bottling machines.
Another objective of the invention is to provide individual locking
indicator extensions depending from the main body of the threaded
closure which have their lower edges turned under the locking
shoulder of the container, and which extensions each has one or
more vertical score lines extending from the lower edge of the
extension up toward one or more horizontal cross-wise slots below
the threaded section, and the action of which on removal of the
closure is to rupture the material along the score line, and
without appreciably flaring the ruptured ends outwardly where the
sharp edges could cause cuts to the fingers during the opening or
reuse of the closure.
Another objective of the invention is to provide two or more score
lines on each indicator extension.
Another objective of the invention is to align each vertical score
line with a connection member extending to the main body of the
closure, such that after rupture the material on each side of the
score line remains firmly anchored at the upper end, and can not
bend outward to present sharp corners to cut the fingers.
Another objective of the invention is to provide a series of score
lines around the circumference of the closure in the lower
extension material, and with each score line aligned with a solid
connection to the main body of the closure, and such that each
segment between score lines has its upper surface anchored at each
end to prevent sharp corners from being presented.
Another objective of the invention is to extend to the complete
circular band type of tamper indicator the arrangement whereby each
vertical score line is positioned in line with the approximate
center of a relatively wide bridge connection member to the main
body of the closure, and thus each segment between score lines
remains anchored at its ends after opening.
Another objective of the invention is to form the closure cap
before it is applied to the container with a series of inwardly
projecting indentations spaced around its circumference to give the
closure a firm elastic grip on the threads of the container to
accurately center the top panel of the closure on the container
mouth so the polyvinyl chloride gasket is uniformly compressed at
all points around the circumference of the side seal during
application, and in order to produce more uniform unlocking
torques.
Another objective of the invention is to form a depression in the
top panel of the closure in such a way as to give greater
resilience to the top panel for more uniform unscrewing torque.
Another objective of the invention is to notch the score line at
one or both ends in order to make rupturing easier, and at the same
time to give rounded corners to prevent cutting the fingers, and to
extend this feature to the complete circular type of tamper
indicator.
Another objective of the invention is to provide embossed
protruding surfaces adjacent to the fracturable score lines to hold
the fingers clear of the sharp edges, and to extend this feature to
other types of tamper prevention systems.
Another objective of the invention is to provide tamper indicating
means of the type that can be applied to pre-threaded closures of
ductile metal or plastic composition.
Still another objective of the invention is to provide mechanical
means in the bottling machine line whereby each closure will be
tightened to a given desired torque, thus eliminating some closures
that are too tight to loosen by hand.
DESCRIPTION OF THE DRAWINGS
Other objectives of the invention will become apparent from the
following detailed description and upon reference to the
accompanying drawings in which:
FIG. 1 is an elevation with partial cross-section of the invention
applied to a container closure of one of the preferred types in
which the closure is drawn from thin ductile aluminum alloy to the
shape shown prior to being threaded in place on the container neck,
and the drawings shows the closure in place on the mouth of the
container ready for threading.
FIG. 2 is a cross-section taken along line 2--2 in FIG. 1, and
shows the score line and the protective bosses in one of the
indicator extensions.
FIG. 3 is a cross-section of the closure body only, and is taken
along line 3--3 of FIG. 1 and shows the depressions made around the
circumference of the main body of the closure to insure accurate
alignment of the closure cup on the mouth of the container before
the threads are roll formed.
FIG. 4 is a plan view showing how the blanks for the closures are
cut from a strip of metal, and how the material for the indicator
extensions comes from the otherwise waste material between the
circles.
FIG. 5 is a partial elevation in section showing the method of roll
forming the threads in the closure and turning the lower edge of
the indicator extension under the locking shoulder of the
container.
FIG. 6 is an elevation showing the completed closure of the FIG. 1
type in position on the container mouth.
FIG. 7 is an elevation at ninety degrees to FIG. 6 to show the two
indicator extensions positioned 180.degree. apart.
FIG. 8 is a partial elevation showing the distorsion and rupture
along the score line after the closure of the type shown in FIG. 1
has been removed from the container, and the score line has
fractured during removal.
FIG. 9 is a partial cross-sectional elevation of the upper end of
the closure positioned on the container mouth, and shows an
alternative means for insuring alignment of the closure cup blank
on the mouth before the pressure head reforms the top panel of the
closure and the threads are rolled into the closure body.
FIG. 10 is a partial elevation showing another design of score line
and slot in which the slot extends to one side only of the score
line, and protruding bosses are provided to protect the fingers
from the sharp edges after fracture.
FIG. 11 is a partial elevation showing another design of score line
and slot, and with the metal of the closure extending down to cover
the locking shoulder of the container neck at the sides between the
two indicator extensions.
FIG. 12 is a partial elevation showing a preferred arrangement of
score lines and slot in which there is a single slot and two score
lines, and the score lines extend up toward the main body of the
closure, and do not intercept the slot, thus insuring anchorage of
the segment at each end after rupture of the score lines.
FIG. 13 is a partial elevation showing a modified version with
three score lines and two slots, and with the same advantages.
FIG. 14 is a partial elevation showing curves slots and with the
material between the indicator extensions extending down to the
lower edge of the locking shoulder on the container neck, and with
protective bosses formed in this material.
FIG. 15 shows the score lines in alignment with the uncut material
between the ends of adjacent slots, so each segment after score
line rupture is firmly anchored at each end to the main body of the
closure to eliminate cut fingers, and with the indicator segments
extending around the full periphery of the closure body.
FIG. 16 is a partial cross-sectional elevation showing the
invention applied to a pre-threaded closure made of plastic, and
indicating how the lower edge of the indicator extension is locked
to the shoulder of the container neck.
FIG. 17 is an elevation of a torquing device to be arranged in line
with the automatic bottling machine for the purpose of mechanically
tightening each closure to the desired torque to insure uniform
unscrewing torque on all closures.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
While the invention will be described in connection with certain
preferred embodiments, it will be inderstood that it is not
intended to limit the invention to these particular embodiments. On
the contrary, it is intended to cover all alternatives,
modifications, and equivalent arrangements within the spirit and
scope of the invention.
The present invention can be applied to a number of types of
container closures already well known in the art. It is
perticularly suited to the type of closure in which the container
mouth is threaded and in which a cylindrical downward facing
locking shoulder is provided on the container mouth just below the
threaded section, and in which the closure is placed over the
container mouth after filling, and threads are then formed in the
closure's cylindrical body to match those of the container. This
has been previously described in reference to U.S. Pat. No.
3,303,955. My invention can also be applied to pre-threaded
closures of metal or plastic.
Referring now to the drawings, FIG. 1 shows an elevation of a
closure in accordance with my invention, and in its intermediate
form prior to being formed to the contour of the container mouth.
The cup shaped closure body 30 is drawn from a sheet of ductile
metal, preferably hard temper aluminum alloy. Cup 30 is shown in
FIG. 1 positioned on the mouth of container 28, which may be made
of glass or plastic. Container 28 has an outer sealing wall 33,
threads 26, and downwardly facing circular locking shoulder 16 just
below the threads. In these specifications, for the sake of
clarity, it is assumed that the container is standing with its
mouth pointing upward as in FIG. 1.
Closure body 30 comprises end panel 10 with depending cylindrical
side wall consisting of upper section 11, knurled band 12, side
panel 13, and wall 15. The knurled band 12 enables the user to turn
the closure by hand, and optionally wall 15 can also be knurled,
but it is shown plain here to simplify the drawings.
The tamper indicating means of the invention, which shows whether
or not the closure has been opened before, comprises indicator
extension 20, along with additional one or more counterparts. FIG.
1 illustrates one design of the tamper indicating extensions,
others being described later in the specifications. Extension 20 is
a curved continuation of the closure side wall, and has a
horizontal cross slot cut through the metal at 21, and a vertical
score line 22 cut part way through the metal and extending from the
lower edge 19 to the region of the cross slot. The score is
preferably on the inner surface to provide greater visual contrast
after rupture has taken place. This line may be a series of small
perforations, or a combination of perforations plus score line. A
notch 23 is optionally cut at the lower end of the score line, and
if desired a similar notch at the upper end. The advantages of the
notches are that they start the fracture more easily by stress
concentration, and also they serve to round the sharp corners,
reducing tendency to cut the fingers. Raised bosses 32 are
optionally pressed in the metal, and serve to hold the fingers
clear of the sharp ruptured edges when the score line breaks as the
closure is removed. They also help to keep the fingers from
slipping with the same effect as knurling.
FIG. 2 is a cross-sectional view taken along line 2--2 of FIG. 1,
and shows extension 20 with score line 22 and protruding bosses 32.
In the design shown in FIG. 1 there are two extension members
spaced 180.degree. apart around the circumference of the closure
body. This is further illustrated in FIG. 7, which shows the
closure in place on the container neck, and with one extension at
20 and the opposite extension at 20'.
The closure is preferably sealed with a polyvinyl chloride gasket
having a thickness of about 0.027 inch. The gasket is shown at 29
in FIG. 1 as a flat disc which is adhesively held to top panel 10.
During the sealing and threading operation, which is shown in FIG.
5, the outer rim of the gasket is drawn down to form an outer
cylindrical seal against outer container shoulder 33. As shown in
FIG. 1, there is a substantial space between walls 11 and 12 and
shoulder 33 when the closure cup is first positioned on the neck.
The inside diameter of cup 30 must be large enough to permit it to
slip freely over the outside diameter of threads 26, and when these
threads are at their largest diameter in accordance with the
tolerance variation in the manufacture of the bottle. Also the
threads are positioned well down from the top panel. As a result it
has been found that with the modern high speed bottling machines,
which operate at speeds of 800 or more bottles per minute, there is
a tendency for the loosely fitting cup to occasionally be tilted to
one side when it is dropped on the end of the bottle. Then under
this condition, when the forming head, shown at 42 in FIG. 5, comes
down under high pressure, it first locks the cup in off-center
position, and then re-forms the end of the closure with the gasket
eccentrically positioned. The gasket is then squeezed too tightly
on one outer side shoulder seal, and too loosely on the other side
180.degree. away. I have found that this is the major reason for
the large variation in unlocking torques with this type of
closure.
What is required therefore is a means to insure that the space
between wall 11 of the closure and wall 33 of the container, in
FIG. 1, be uniform around the circumference. In my invention this
is accomplished by providing a series of depressions, or
indentations, as shown at 31, which are uniformly spaced around the
side wall, and are just deep enough to decrease the inside diameter
of the closure in the area of the container threads 26 so the
closure fits snugly over the threads. There are six or more of the
depressions, and they are springy to suit normal variation in
thread diameter. I find that this improvement results in the
closure being always positioned squarely on the end of the
container and with space between walls 11 and 33 always uniform
around the circumference. The depressions are made with gradually
sloping walls, so when the center wall 13 is threaded, as shown in
FIG. 5, the depressions are ironed out and disappear. FIG. 3 is a
cross-sectional view taken along line 3--3 of FIG. 1 through the
closure wall, and shows a preferred depression construction at 31.
This is also shown in FIG. 1 at 27.
FIG. 4 shows how blanks for the closures are cut from a strip of
ductile metal sheet, which is preferably hard temper aluminum alloy
having a thickness of 0.008 to 0.010 inch. Two consecutive blanks
35 and 35' are cut from sheet 18 to diameters 34 and 34', and with
extensions 36 and 37 on one blank and 36' and 37' on the other,
which extension form the indicator extensions, such as 20 in FIG.
1. The diameter at 34 is made just large enough to form the side of
the closure down to point 51 in FIG. 7, which is intermediate
between two adjacent extensions. It will be noted that the width of
supply strip 18 has to be only slightly wider than diameter 34 by
the small trim at 38 and 39, and that the projections 36 and 37 are
cut from waste material between the punchings. The trim for blank
35' is shown at 38' and 39'. Whereas this shows the saving if the
blanks are cut from a narrow sheet of material, a like saving
results if the blanks are cut from a wide sheet, as there is space
between the circles for the extension projections. Cutting the
extensions in this way from the waste material between the circles
results in a reduction of 20 to 25 percent in the amount of sheet
material required for the closure, as compared with previous
complete locking band type of tamper indicators.
The sheet metal blank which is cut from flat stock as shown in FIG.
4 is next drawn into the cup form of FIG. 1. The slots in the
extensions and the score lines may be cut at the same time as the
flat blanks are punched out, or preferably they may be cut after
the cup shape is drawn. It is desirable to cut the slots with an
inclined cutting tool so the upper and lower edges of the slot do
not interfere when the extension bends outward on removal of the
closure.
The method of application of the closure by production bottling
equipment to the mouth of the filled container is shown in FIG. 5
utilizing the improvements of my invention. Referring to FIG. 5,
container 28 has end sealing surface 14, side sealing shoulder 33,
threads 26, and annular locking shoulder 16. It is important that
all these surfaces be smooth and formed on the container to close
tolerances in order to effect a closure system that is leak proof
against high pressure in the container, and at the same time one
that has uniform and relatively low removal torque, and suitable
for both new and recycled containers.
In FIG. 5 the closure 30 in the cup form of FIG. 1 is placed on the
upper end of the container, and then pusher element 43 is pressed
down on end panel 10 by rod 41, actuated by hydraulic pressure or
mechanical linkage. As the closure body is pushed down by 43 it is
guided by the springy depressions 31 shown in FIG. 1, and these
press snugly against the tops of threads 26, serving to guide and
position top panel 10 concentrically on the end of the container
regardless of the exact position of the container mouth with
respect to the center-line of pusher 43. Pusher 43 comprises an end
disc 43 which is vulcanized to flexible rubber connection 40, and
40 is vulcanized to rod 41. This flexible mounting of pusher disc
43 permits 43 to move sideways with little resistance if
necessary.
Pressure head 42 is now brought down while pusher 43 still
maintains pressure contact on top panel 10, holding the top panel
concentrically on the container mouth due to friction of the PVC
gasket against end 14. The pressure head has a tapered entry
surface at 46 which initially engages the outer shoulder of panel
10, which panel at this point is of the size shown dotted at 11 in
FIG. 5. If the top panel is off center relative to the tapered
opening 46, due to the bottle neck not standing exactly in line,
then tapered opening 46 moves the closure and neck over until they
are concentrically positioned, and flexible rubber member 40
provides sufficient flexibility to permit top panel 10 and member
43 to move over sideways as required.
As a result of this arrangement, the outer diameter of the closure
is re-drawn concentrically by head 42 from larger diameter 11 to
new diameter 24, and the outer rim of gasket 29 is formed down to
position 29', and with equal side pressure and compression of 29'
around the full circumference of the closure. In systems used
here-to-fore there was no way to insure concentric re-forming of
shoulder 11 with the result that the gasket at 29' was often
over-compressed on one side and under-compressed on the other,
giving a higher unscrewing torque and a less satisfactory seal.
Hereto-fore the unguided container neck has stood up inside a
loosely fitting cup closure blank without any guiding means to
align the two parts concentrically while the end panel was
reformed, often causing the turned down edge of the gasket to be
too narrow on one side and too wide on the other.
Now while pressure head 42 in FIG. 5 maintains high pressure on the
top and sides of gasket 29, the next step is to roll the threads 25
in side wall 13 to match the threads 26 on the container neck using
thread roller 44. Thread rollers are generally used in pairs to
balance the pressures. Roller 45 turns the lower edge 19 of
extension 20 into locking position 47 under container shoulder 16,
as well as the lower edges of similar other indicator extensions
around the periphery. The application of the closure is now
complete, unless re-torquing is provided as described later.
The finished closure 30' is shown in FIG. 6 on container 28. The
top of the closure is 10, the reduced diameter shoulder is 24, the
knurled band is 12, and band 15 may also be knurled, the thread
rolled in the closure body is 25, and the indicator extension is 20
with its turned under edge 47 locked to shoulder 16. The sloped
sides of the extension are 17 and 18, and the cross slot is 21. The
score line is 22, with notched entry, and protection bosses are
32.
The use of two extension members spaced equally around the
circumference is the preferred design, and is shown in FIG. 7,
which is a view taken at 90.degree. from FIG. 6. One extension is
shown at 20 with slot 21, and the other at 20' with slot 21'. The
intermediate lowest point in the main body of the closure is at
51.
I have found that closures made in accordance with my invention
require a low unscrewing torque to rupture the score line, and one
that is on the order of 4 inch pounds. Actually this is not
generally a factor, as the highest torque is that required to start
turning the closure against the friction of the seal. My tests show
that when unscrewing any threaded-in-place tamperproof closure, the
maximum torque and the loss of pressure take place at about one
twentieth of a turn, while it takes a quarter turn to break the
tamper score lines, and by this time the seal torque has almost
disappeared.
FIG. 8 shows the tamper indicator extension in accordance with my
invention after removal from the container, and shows the distorted
position of the parts of extension 20. The bending action has
separated the ruptured ends along score line 22', and the lower
edges of slots 21 have tilted down, increasing the opening of the
slot at points 53 and 54. Because of the strength of the material
in the wide supporting spaces 49 and 50, a considerable part of the
freedom for removal of the closure extension over shoulder 16 is
attained by partial straightening out of the turned-under lip 47,
and the sharp fractured edges along the score line remain in
alignment with each other so there is little danger of cutting the
fingers when turning the closure. Bosses 32 also give added
protection.
Referring to FIG. 6, it is important to understand that the
dimensions and position of slot 21 can be proportioned to give
efficient and sure-fire rupture along score line 22 with easy
unscrewing torque for any container neck size. I have found that
for the presently most commonly used bottle-neck size, which has an
outside diameter of about one inch, and for the design in FIG. 1,
typical dimensions of the extension indicator system are the
following. The width of the extension 20 at its lower edge may be
three-fourth inch; the width of slot 21 can be one-half inch and it
may be positioned five thirty-seconds to three-sixteenths inch
above lower edge 19 before it is bent under the shoulder. The slope
of sides 17 and 18 should be such as to make the spaces from the
ends of the slot to the sloped sides each about five-sixteenth
inch. This distance is substantial, and serves to give rigidity to
the lower parts of extension 20, partly because of the distance
from the slot to the sloped sides and partly because these surfaces
are arced, which increases their stiffness. It is this stiffness
that resists the lower edge at 47 from bending outward too easily,
and thereby the unscrewing action places a high downward force
along the two halves of the inwardly turned lip 47 against shoulder
16. This force in turn creates high stresses along fracturable
score line 22. Since the resistance to this force is greater when
the score line is longer, it is desirable to reduce this length by
notch 23 in FIG. 1.
FIG. 9 shows an alternative way to effect more accurate alignment
between the top panel of the closure and the end of the container
at the start of the closure application. A shallow 59 recess is
pre-formed in top panel 60, and the outer rim is beveled at 58
around the circumference. PVC gasket disc 57 is formed to this
contour when it is heat sealed to the inner surface of top panel
60. Outer wall 61 of the closure is cylindrical and large enough to
slip over threads 26 of container 28. After initial placing of the
closure on the container mouth, it is pushed down firmly by pusher
disc 43 supported on flexible rubber mounting 40, and container end
62 naturally slides into the groove in the gasket as shown. This
serves to center the end of the closure accurately on the end of
the container, and to hold it positioned when the pressure head is
brought down. The pressure head re-forms the inclined wall 58 to
the form shown at 24 in FIG. 7. There are other advantages in
providing a depression as shown in FIG. 9 or a circular groove in
the top panel of the closure. One is that it provides greater
radial resilience or elasticity to the top panel as compared with a
flat surface, and this increases the uniformity of the side sealing
pressure. It is less affected by variation in the diameter of the
outside sealing shoulder of the container. The resilience also
off-sets variation in the diameter of the closure top panel caused
by wear of the bore in the pressure head. The depression stiffens
the top panel against deflection upward from internal pressure that
tends to reduce the effectiveness of the top seal. Most of these
advantages can be obtained if the depression is formed in the top
panel by pressing or rolling after the closure has been applied to
the neck.
Recently glass containers for use with threaded-in-place closures
are being made with a sharp projecting bead on the side seal
shoulder as shown at 63' in FIG. 9. This bead sinks into the
polyvinyl chloride gasket at the turned down rim, and improves the
tightness of the seal, and with less wall pressure required. This
feature combined with the concentric alignment feature of my
invention substantially reduces the unscrewing torque.
FIG. 10 shows a partial elevation of another variation in which
closure 70 with threaded part 69 has an indicator extension 65,
with turned under edge 64 engaging locking shoulder 16 of container
28. The slot 66 is inclined and relatively long, and is positioned
to one side of score line 67, which is off-center in the extension.
The upper end of the slot may extend into the cylindrical portion
of the closure above the extension. Raised bosses 32 serve to
protect the fingers after rupture of the score line. Notch 68 makes
breaking of the score line easier, and also rounds the sharp lower
corners after rupture. This design is somewhat easier to remove,
requiring less torque, because of the greater length of slot to one
side of the score line.
Another variation is shown in partial elevation in FIG. 11. Closure
72 has threaded sections 71, indicator extension 75, lower edge 74
turned under locking shoulder 16 of container 28, score line 78,
and double curved slots 76 and 77. A perforation at 79 assists in
rupture of the score line. Raised bosses 32 are for protection of
the fingers. An alternative construction of the side wall of the
closure is shown at 73, where the sides between the indicator
extensions are brought down over the face of shoulder 16. This is
to improve the appearance and to give added support to the sides of
the indicator extensions, but it requires more sheet material to
make the closure than the previously described types.
FIG. 12 shows a partial elevation of a much preferred form of the
invention. Closure 80 has threaded section 81, and indicator
extension 82, which has its lower edge at 87 turned under locking
shoulder 16 of container 28. There are two score lines, 83 and 85,
and horizontal cross slot 84. The score lines are positioned just
beyond the ends of the slot. The segment which hinges outwardly
when the score lines rupture is 86. The score lines do not
intersect the cross slot at their upper ends, but pass a short
distance away from it at each side. Therefore, when the score lines
rupture as the closure is removed, the segment remains firmly
anchored along its upper edge to the main body of the closure, held
by the narrow metal strips at each end between the slot and the
scores. Since the upper edge of the segment remains attached at
each end to the closure body, there is no possibility of cutting
the fingers along this edge.
A variation of this form is shown in partial elevation in FIG. 13.
Closure 90 has threaded section 91, and indicator extension 92 with
its lower edge turned under at 93 in locking engagement with
shoulder 16 of container 28. There are three score lines 94, 95,
and 96, and two horizontal slots 97 and 98, so positioned that the
score lines do not intersect the slots. The segments between the
score lines are 99 and 100. When the closure is unscrewed, the
score lines rupture, and the two segments hinge outward. The upper
edges of each segment remain firmly anchored at each end to the
main body of the closure. The segments in this arrangement are not
as wide as those previously shown. Bosses 32 serve to provide added
protection against cutting the fingers. These projecting bosses can
be applied to any of the indicator designs, including FIG. 15.
Whereas they are shown as circular, they may be bulges of any
shape, such as rectangular ridges paralleling the score lines.
The various designs of indicator extensions illustrated in FIGS. 1,
6, 10, 11, 12, and 13 can be used in various multiples per closure.
Use of two extensions per closure is the most economical on
material usage. Three extensions work well and save material. Four
or five extensions can also be used if desired. Actually the use of
only two or three indicator extensions applies principally to the
most common size of screw cap closure which is used almost
universally, and in which the outside diameter of the locking
shoulder 16 is one and one eighth inches. The invention is also
applicable to larger sizes of container mouths, which may require a
larger number of extensions.
Where a more or less continuous series of indicators is desired
around the circumference, the advantages of my invention can be
obtained by going to the arrangements shown in FIG. 14 and FIG.
15.
FIG. 14 shows another variation of the tamper indicator system.
Container closure 101 with threaded section 102, has a number of
indicator extension segments around the periphery, such as 103 and
108. Segment 103 is bordered at its ends by score lines 104 and 105
and above by curved slot 106, and its lower edge is turned under
locking shoulder 16 of container 28 at 107. Segment 108 is bordered
by score lines 109 and 110, and curved slot 111 above, and is
locked under shoulder 16 at 112. The segments are spaced by
sections of the closure's cylindrical body which extend down to the
lower edge of the locking shoulder, such as 113 and 114 in the
drawing. These sections, which do not hinge out when the closure is
removed, preferably have bosses 32 to protect the fingers. The
arrangement shown in FIG. 14 has four segments that hinge out when
the closure is unscrewed, and four intermediate spacer
sections.
FIG. 15 shows a partial elevation of the invention applied to the
arrangement wherein the indicator extensions extend in a continuous
series around the periphery of the closure. In FIG. 15, closure 120
has threaded-in-place section 121, and below the threads is a line
of horizontal cross slots 130, 131, and 132. The slots extend
completely around the closure body and the spaces between the ends
of adjacent slots are about 1/8 inch wide. Vertical score lines, as
shown at 123, 125, 127, and 129, extend from the lower edge of the
closure to the line of the slots, or even slightly above. The score
lines also extend around the periphery, and each score line is
lined up with the uncut material between the slot ends, preferably
at the mid-point. The score lines and slots define segments 122,
124, and 126, and others around the periphery. The segments have
their lower edges turned under locking shoulder 16 of container 28
as at 128. The lower ends of the score lines may be notched to make
rupture easier, and to eliminate sharp corners. When the closure is
removed, the score lines rupture, breaking in tension, and the
segments bend outward and remain firmly anchored at each upper end.
Raised bosses can be provided, such as shown at 32 in FIG. 14, and
optionally there can be perforations above the scores as at 79 in
FIG. 11.
FIG. 15 shows the proportions when there are eight segments around
the periphery. Six or eight is the preferred number. It is
important to note that on unscrewing, each segment hinges on the
attachments to the closure body at its extreme ends, and because
the slot is an arc, the upper and lower surfaces of the slot tend
to come together. The slot must therefore have its upper and lower
edges spaced well apart, or be curved as in FIG. 14, or be cut with
an inclined tool. The width of the metal between the ends of
adjacent slots should be 0.10 to 0.125 inch, half of which goes to
support the segment on one side and half to the other side, if the
score bisects the space. These attachments protect the fingers from
the sharpness of the ruptured score lines at the upper ends.
Because each segment has the same attachment at the top as the
adjoining segment, all the segments hinge out the same amount, and
this keeps the lower corners in line with each other so they will
not cut the fingers, especially if the corners are rounded, as by
notching as shown at 23 in FIG. 1. In order to permit the segments
to hinge out freely, it is essential that there be no bridge
connections within the cross slots, such as has been the case in
tamper indicators used up to now.
FIG. 16 is a partial cross-sectional view showing closure 140 on
the end of container 28, and in which the closure is completely
formed and threaded before it is applied to the container. The
closure may be of plastic or metal. The top panel is 141, and
sealing is effected by gasket 149 made of a material such as
polyvinyl chloride and optionally with a compressible backing
gasket 151 made of a resilient material like composition cork,
serving to give added cushion. This is advisable because the
threads do not fit as well as when they are rolled in at assembly,
and also there is only one seal between the gasket and the end
surface 150 of the container. A knurled band is at 142, and threads
143 in the closure match those on the container mouth at 144. The
tamper indicator extension is 147, the cross slot is 145, and the
score lines 146 is shown dotted. The arrangement of the slot and
score line may be similar to those previously described in various
designs for the ductile metal closure. The lower edge 148 of the
extension is beveled in the back so it can be slipped over the
container mouth when first applied, the extensions deflecting
outward as necessary, but without straining the score lines. When
the lower edge reaches the lower locking face of container shoulder
16, it snaps into the position shown. The container may have a
supplementary annular shoulder shown dotted at 152 to protect edge
148 so it can not be pried up by anyone trying to tamper with the
contents. The container is shown as made of plastic, but it may be
glass or other material.
It is very difficult even with the closure application method
illustrated in FIG. 5, and described in the specifications, to
attain a uniform unscrewing torque under the varying conditions
encountered in bottling plants. The system described for insuring a
concentric gasket and concentric re-forming of the top shoulder of
the closure eliminates one principle cause of torque variation.
Other adverse factors are wear of the pressure head re-forming
bore, wear of the thread rollers, and container dimensions not
within specifications. Added to this is the large variation in the
strength of the fingers of the user, which dictates a lower
unscrewing torque than hereto-fore attainable. Commercial
tolerances run 4 to 17 pound inches, yet anything over 6 inch
pounds is difficult to unscrew without a tool.
In order to produce a more nearly perfect closure application in
accordance with my invention, a torquing machine is positioned in
the bottling line following the closure application and sealing
operation. The torquing unit may have multiple heads in order to
operate at high speed, and with the container conveyor traveling in
an arc around the unit so several containers can be torqued
simultaneously. FIG. 17 shows a single torquing head to illustrate
the principle of operation, and which is readily adaptable to a
multiple unit by providing several heads on the common rotary
mounting. Referring to the drawing, container 28 has been sealed
with closure 160, which has tamper indicator 158, and upper knurled
band 159. The container is carried past the unit by an extension of
the same conveyor used to take it through the bottling machine, and
which may be as shown, comprising carrier cup 161 on wheels 162
traveling on rails 163, and drawn by guided chain 182.
A rubber faced back-up element 170 is mounted on bracket 183, which
is attached to sleeve 166 on support column 165. The vertical
column 165 is arranged to turn in base 164, and driven by sprocket
183, which is connected to the main conveyor driving unit. When it
is time to torque a closure, the container is locked against
rotation by applying air pressure to cylinder 168, causing rod 169
to press rubber faced block 167 against the container wall, which
is backed up by 170. The upper elements are mounted on arm 171. A
yoke 173 is supported on pin 177, which can move up and down in
guide member 172. At the lower end of 173 is head 178, attached by
flexible rubber connection 179, and having a serrated bore on its
under side that fits over the knurled band of the closure to hold
it securely for the application of torque. The flexible connection
prevents any strain on the closure.
As the container advances on the conveyor, the whole upper torquing
assembly rotates with vertical column 165, and the level of member
173 is determined by its supporting roller 174, which rides on a
circular track 175. At the torquing point, there is a depression in
the track, as shown dotted at 176, and when the depression is
reached it cams the assembly down, positioning head 178 on the
closure, and gripping it by the knurled band.
A torque can now be exerted on the closure by applying air pressure
to air cylinder 179, which is supported on clevis 180, and is
connected to yoke 173 by piston rod 181 and clevis 182. The
pressure of the air can be regulated to apply any desired torque to
the closure. The container clamping mechanism in FIG. 17 is shown
in the closed position. In the actual design, to facilitate entry
of the container into the space between back-up 170 and the pusher
167, these units may be arranged to grip the sides of the container
at 90.degree. from the way it is shown.
Alternatively, a torquing means can be incorporated in each of the
multiple heads of the closure sealing unit, such as shown in FIG.
5. To accomplish this a clamp is provided to keep the container
from turning, the pressure head is raised slightly after the
threads are rolled and just enough to take the pressure off the end
and side seals, the pressure head will have a serrated bore to
engage the upper knurled band, and then the torquing effort will be
provided by slightly rotating the pressure head under the required
inch pounds of torquing force. The tamper extension lower edge can
be turned under before or after the torquing.
The torquing device can be used in either one of two ways. All
closures can be torqued in the tightening direction, thereby
insuring a minimum degree of tightness, and only the less tight
closures will be turned slightly. The other and preferred system is
to first apply a torque in the unscrewing direction to release each
closure slightly, and then to re-torque to the desired degree of
tightness. This insures that each closure will require the same
desired unscrewing torque, and is the only way to accomplish exact
uniformity, and thereby to bring the opening torque down to an
acceptable level of about 3 to 6 inch pounds. As previously pointed
out, it requires very little arc or turning to loosen the closure
seal, and this small amount of rotation does not approach the point
where the score lines are affected.
In the claims that follow it is assumed that the container is
standing with its mouth pointing upward. Reference to score line
indicates the preferred means for decreasing the strength of a line
of the material by cutting a groove about half way of more through
it, and preferably on the inside surface. Other means such as
perforations or score line plus perforations are considered
optional. The cross slots are substantially horizontal, but may be
slightly inclined, may project up into the main body of the
closure, or may be curved a small amount without departing from the
claims. The slots are preferably cut with an inclined tool, as
shown at 21 in FIG. 5, as this reduces the chance of the edges
coming together to resist hinging up of the segment.
In the claims the definition of the word "score line" is a weakened
line in the material of the closure which is rupturable by reason
of the weakening, and the weakened line may comprise a line where
the material is thinner by reason of a score line groove on either
side of the material or on both sides, or the weakened line may be
due to perforations in the material, or it may be a combination of
score line groove plus perforations. In the claims it is understood
that a narrow band of knurling is preferably provided around the
periphery of the cylindrical body of the closure just above the
threaded section, and optionally a second knurled band just below
the threaded section, to facilitate turning the closure by
hand.
It will be apparent that while I have shown and described the
invention in several preferred forms, changes may be made without
departing from the scope of the invention, as sought to be defined
in the following claims.
* * * * *