Tamper-evident cap construction

A tamper-evident cap construction for a dispenser, comprising a cap body having a discharge opening, a screw cap carried thereon and adapted to close off the discharge opening, and a frangible tab that is integral with the screw cap and which extends outwardly over an exposed exterior surface of the body and is integral therewith by virtue of a common fused juncture area at the surface. Preferably the fusing takes the form of a sonic weld. The tab has a transverse line of weakness which can be adjacent to either the point of attachment of the tab to the screw cap, or else to the fused area. The tab normally prevents relative turning between the screw cap and the cap body, but can rupture when a turning force is applied therebetween, having a magnitude which is less that required to separate the tab from the body at the location of the fused juncture. Rupturing of the tab thus provides an indication to the consumer that possible tampering with the container has occurred, since the remaining broken ends of the tab are then readily visible.

BACKGROUND 
This invention relates generally to tamper-evident closures for containers, 
and more particularly to closure constructions of the type which employ 
breakable strips or lugs which are intended to rupture in the event that 
the container is tampered with, prior to purchase or initial use by the 
consumer. 
Various arrangements have been proposed and produced, for indicating that a 
particular container may have been tampered with. 
U.S. Pat. No. 3,455,478 illustrates one approach, which is typical of that 
employed by a number of others, namely providing a closure cap with a 
collar that is connected to the cap by thin, frangible webs or bridges 
which are intended to break upon removal of the cap. In this patented 
construction, the collar has an internal bead which, during assembly, is 
forced over a cooperable external bead on the neck of the container. The 
collar is thus permanently retained on the container even after the cap is 
removed by the consumer. 
A somewhat similar arrangement is shown in U.S. Pat. No. 3,673,761, except 
in this latter device, instead of employing a fixed internal bead on the 
collar, following installation of the cap and collar, the lower edge 
portion of the latter is heated and thereafter rolled over an external 
bead on the container neck. 
Many of the dispensers in use today involve two-part caps, one part 
normally referred to as a base cap part or cap body, and being adapted to 
be permanently retained on the neck of the container, and the other part, 
commonly known as the screw cap part, being capable of being unscrewed 
from the base cap part or cap body. The necessity for employing this type 
of construction is that it is often difficult to mold a container with a 
relatively complex neck configuration of a type that could accept certain 
screw caps directly. As a result, the neck of the container is provided 
with a relatively simple configuration, such as a retention bead, which 
can cooperate with a mating retention structure on the base cap part or 
cap body. The arrangement between the base cap part and the container is 
usually such that a strong and permanent retention is had. This is usually 
accomplished by providing suitable cooperable bead structures as mentioned 
above, or by screw thread arrangements associated with locking ratchet 
teeth, etc. In practically all cases, such a construction discourages 
attempts to remove the base cap part or cap body from the container neck. 
Problems have been encountered, however, in providing a container which 
would indicate tampering involving attempted removal of a screw cap from 
the base cap or cap body. Since the screw cap and cap body are not capable 
of being molded as a single piece, especially where screw threads are 
involved, the use of break-away strips has not, to my knowledge, been 
successful. The employment of glues or adhesives is considered to be too 
time consuming and messy, as well as not providing a reliable bond. 
SUMMARY 
The above disadvantages and drawbacks of prior tamper-evident closure 
constructions are largely obviated by the present invention, which has for 
one object the provision of a novel and improved tamper-evident cap 
construction which is both simple in its structure and reliable in 
operation. 
A related object of the invention is to provide an improved tamper-evident 
cap construction as above set forth, wherein there is featured a positive 
indication of tampering or unauthorized use, thereby protecting the 
consumer against possible harm from tainted food, medicines or other 
drugs, etc. 
Still another object of the invention is to provide an improved 
tamper-evident cap construction as above characterized, wherein the 
tamper-indicating means is readily visible from above and from the side of 
the container, so as to immediately draw the attention of the consumer as 
he or she is handling the container. 
Yet another object of the invention is to provide an improved 
tamper-evident cap construction of the kind indicated, wherein 
high-production techniques can be employed so that the overall cost is 
low, and wherein the additional expense involved with including the 
tamper-evident feature is minimal. 
A still further object of the invention is to provide an improved 
tamper-evident cap construction as outlined above, wherein the added 
plastic material involved with including the tamper-evident feature is 
extremely low, thus keeping the device competitive from the commercial 
standpoint. 
The above objects are accomplished by a tamper-evident cap construction, 
comprising a cap body having a discharge opening, a screw cap receivable 
on the cap body for selectively closing off the discharge opening, and a 
frangible tab integral with the screw cap and having a portion extending 
past the periphery thereof in overlying relation to an exposed exterior 
surface of the cap body. The tab ultimately is also integral with the cap 
body by virtue of a common fused juncture area on the exposed exterior 
surface so as to resist relative turning between the screw cap and cap 
body. The tab has a transverse line of weakness which is adapted to 
rupture when there is applied to the screw cap a turning force having a 
magnitude which is somewhat less than that required to separate the tab 
from the cap body at the location of the fused juncture. Rupturing of the 
tab thus provides to the prospective user an indication of possible 
tampering.

Referring first to FIGS. 1-4 there is illustrated a closure cap 
construction generally designated by the numeral 10, comprising a base cap 
or cap body 12 and a screw cap 14. Disposed on the inner surface of the 
body 12 are two annular rings or retention beads 16, 18 which cooperate 
with similar structures on the neck of a container (not shown), in order 
to provide a permanent retention of the part 12 thereon. The beads 16 and 
18 also provide a secondary seal between the container and cap body 12. 
The underside of the body 12 has an annular flange 20 which is receivable 
in the container neck, and seals thereagainst. Also a depending duct 22 
provides communication with the discharge passage or opening 24 of the 
body 12. 
The exterior of the body 12 is provided with threads 26 and also a pair of 
ramps or cam tracks 28, 30 upon which lugs (not shown) on the underside of 
the screw cap 14 ride. The arrangement is such that a more positive 
unscrewing of the screw cap 14 is made possible by the provision of the 
lugs riding on the cam tracks 28 and 30. 
Disposed at the upper portion of the body 12 is a stopper plug 32 of 
generally cylindrical configuration, supported by two legs 34 and 36. 
Referring again to FIG. 2, the screw cap 14 has a generally conical outer 
surface configuration, and an apertured flat top portion 38 with a 
dispensing aperture 40 that is normally sealed off by the stopper plug 32 
when the parts are in the position illustrated. On the interior wall of 
the screw cap are threads 42 that engage the threads 26 of the cap body 
12. The threads 26 and 42 operate for the most part to urge the screw cap 
14 toward its closing position, as shown, whereas the lugs on the 
underside of the screw cap and the cam tracks 28 and 30 operate to force 
the screw cap open when it is unscrewed. In the open position the stopper 
plug 32 is removed from the aperture 40, as can be readily understood. 
In accordance with the present invention novel tamper-evident means are 
provided on the screw cap 14 and cap body 12, for indicating if the part 
14 has been disturbed prior to its initial use by the consumer, said means 
comprising a frangible tab 44 particularly illustrated in FIGS. 1-4, the 
tab 44 being molded integral with the screw cap 14 and being made integral 
with the cap body 12 by virtue of a common fused juncture area 46 on the 
exposed exterior surface 48 of the cap body 12. As illustrated, this 
exposed surface 48 is somewhat conical in shape, having a slight curvature 
or concave cross sectional configuration. Also, by the invention the tab 
44 has a transverse line or section 50 of weakness and is adapted to tear 
or rupture along this line when the screw cap 14 is subjected to a 
predetermined turning force, which force may be less than that which would 
be required to separate the tab 44 from the fused area 46. As shown, the 
tab 44 is elongate and extends radially outward past the periphery of the 
screw cap 14, and the transverse line 50 of weakness is generally 
perpendicular to the axis of the tab 44. 
FIG. 3 shows the assemblage of cap body 12 and screw cap 14 with the tab 44 
prior to the fusing of the latter to the body 12. The fusing preferably 
takes the form of what is known as a sonic weld, wherein heat is applied 
to the materials to be fused, by electrical induction. The equipment for 
accomplishing sonic welding is known, and accordingly it is not 
illustrated or described. 
Further in accordance with the invention there is provided on the exposed 
exterior surface 48 an upstanding projection 52 that is located beneath 
the tab 44 and which applies an upward bias thereto at a location adjacent 
its center. The tab 44 is molded integral with the screw cap 14 and has 
the configuration of FIG. 4 prior to assembly. Following assembly, the tab 
44, being resilient, is stretched over the projection 52 and downwardly 
onto the periphery of the surface 48, and the sonic welding is then 
accomplished at location 46. In this manner, there is imparted to the tab 
44 a cross-sectional configuration somewhat similar to the capital letter 
"S". 
Upon the occurrence of tampering, or alternately during the initial use of 
the dispenser, the tab 44 ruptures along the line 50, and the torn end 54, 
shown dotted in FIG. 2, is propped up by the projection 52, this 
constituting a pronounced indication of tampering to the consumer, more so 
than would be the case if the projection 52 were to be omitted. 
The particular form of the projection 52 is of no special significance, 
except that it is preferably located to extend along the area where the 
tab is ultimately positioned. I have found that by making the projection 
52 arcuate, or semi-circular, the desired result is achieved, and there 
occurs little or no interference with the fusing or welding operation. 
Another embodiment of the invention is shown in FIGS. 5-7, wherein similar 
reference numerals have been applied to corresponding parts of like 
construction. The cap body is indicated 12a, and the screw cap 14a. The 
tab 44a has a modified construction in that the line 50a of weakness is 
disposed nearer the attachment of the tab 44a to the cap body 12a than its 
point of attachment to the screw cap 14a. The internal structures of the 
cap body 12a and screw cap 14a of these figures are identical to those of 
the first embodiment. 
In the present instance, the tab 44a would be molded integral with the 
screw cap 14a, and initially would extend straight out from the periphery 
thereof, as in FIG. 4. During the fusing operation at the surface area 
46a, the tab 44a would again have imparted to it a cross sectional 
configuration similar to a flattened letter "S", as in FIG. 6. In this 
figure, there is shown in dotted outline the torn or ruptured end 54a of 
the tab, following initial use of the dispenser. The end 54a is again 
propped up by the projection 52a on the surface 46a. FIG. 7 illustrates 
the appearance of the tab 44a prior to its being fused to the cap body 
12a. 
From the above it can be seen that I have provided a novel and improved 
tamper-evident cap construction which is both simple in its structure and 
reliable in operation. Its simplicity has the advantage that education of 
the consumer is not required in order for him to understand the 
tamper-evident feature. Moreover, there is no doubt as to whether or not 
the tab is intact, because it is prominent from both above and the side of 
the container. 
Due to the small amount of additional material represented by the tab, 
there is little added expense, as far as extra plastic being required. 
Moreover, the fusing step can be quickly and economically carried out by 
production techniques with a minimum of time and effort. 
The device is thus seen to represent a distinct advance and improvement in 
the technology of tamper-indicating closure constructions. 
Each and every one of the appended claims defines a distinct aspect of the 
invention which is separate from all others, and accordingly each claim is 
to be treated in this manner when examined in the light of the prior art 
devices in any determination of novelty or validity. 
Variations and modifications are possible without departing from the spirit 
of the claims.