Hinged cap separable from bottle at the time of disposal

A hinged cap comprising a cap body, an outer cylinder formed integrally with said cap body so as to cover the outer surfaces of said cap body and said skirt portion, and an upper closure coupled by hinges to the upper end portion of said outer cylinder, wherein the skirt portion of said cap body is provided with a plurality of slits extending in the axial direction maintaining a distance in the circumferential direction, the skirt portion of said cap body and said outer cylinder are separated away from each other via cut surfaces but are formed integrally together via a plurality of breakable bridge portions and are formed on the upper side or the lower side of the cut surfaces, and the outer surface of the skirt portion of the cap body and the inner surface of the outer cylinder are intimately contacted to each other at the cut surfaces in a state where at least the cap body is fitted to the mouth of the container. The cap has a highly reliable sealing structure and, after used, can be easily removed from the mouth of the container without using any tool. The cap can be produced through a series of steps and offers excellent tamper-evidence.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a hinged cap separable from bottle at the 
time of disposal. More specifically, the invention relates to a hinged cap 
that is strongly fitted and secured to the mouth of a container but that 
can be easily removed from the mouth of the container without using any 
special tool, and that offers excellent sealing and tamper-evidence. 
2. Description of the Prior Art 
Plastic caps have an excellent moldability, exhibit excellent flexibility 
and can, hence, be strongly fitted and secured to the mouths of containers 
by the capping operation to maintain high degree of sealing. 
In many cases, however, the plastic caps are used for a glass bottle and 
the plastic containers made of materials different from the cap materials. 
To meet the demands for reusing the resources and for separating the cap 
from the bottle at the time of disposal, it has been desired to easily 
remove the caps from the mouths of the containers without using a tool 
such as cutter or the like. 
There have been proposed a variety of caps separable from bottle at the 
time of disposal. For example, Japanese Utility Model Laid-Open No. 59247 
/1994 discloses a container closure comprising a cap body fitted and 
secured to the mouth of a container, a cylinder screwed to the cap body, 
and an overcap coupled by hinges to the cylinder. In the container 
closure, the cap body comprises a top plate portion having a breaking 
portion for forming a flow-out port, a side wall coupled integrally to the 
peripheral edge of the top plate, and an inner ring that downwardly 
extends from the inner surface of the top plate portion maintaining a 
suitable gap from the side wall. That is, the cap body is secured to the 
mouth of the container as the mouth of the container is fitted to between 
the side wall and the inner ring. Besides, the side wall is formed being 
broadened toward the back thereof or has a plurality of slits extending in 
the direction of height maintaining a suitable distance in the 
circumferential direction, so that the cap body can be removed from the 
mouth of the container without using any special tool. Furthermore, a 
screw thread is formed on the upper outer peripheral surface of the side 
wall to hold the cylinder. When the cylinder is engaged with, and held by, 
the side wall, the side wall is pushed by the cylinder and is firmly held 
by the mouth of the container to maintain good sealing. 
According to the container closure of the above prior art, the cylinder 
formed integrally with the overcap is turned, so that the cap body is 
removed from the side wall. Thus, the cap body can be easily removed by 
hand from the mouth of the container and can, hence, be separated easily 
from the container at the time of disposal. 
Furthermore, Japanese Utility Model Laid-Open No. 9751/1995 discloses a 
container closure comprising an inner plug fitted and secured to the mouth 
of the container, an outer cylinder and an overcap. Like the cap body 
mentioned above, the inner plug of the container closure has, formed in 
the top plate portion thereof, a breaking portion for forming a flow-out 
port, and permits the mouth of the container to be fitted between the side 
wall and the inner ring. Moreover, the top plate portion has an annular 
erected portion that is so formed as to surround the breaking portion, and 
the overcap is fitted being screwed about the outer surface of the erected 
portion. The outer cylinder is so provided as to surround the outer 
peripheral surface of the side wall of the inner plug, the outer cylinder 
and the side wall of the inner plug are formed integrally together via a 
weakened portion, and a reinforcing ring is fitted in space between the 
inner surface of the outer cylinder and the outer surface of the side 
wall. That is, in a state where the container closure is fitted to the 
mouth of the container, the side wall of the inner plug is pushed onto the 
wall of the mouth of the container by the reinforcing ring, whereby the 
inner plug is firmly secured to the mouth of the container to maintain 
good sealing. The outer cylinder can be easily torn away from the inner 
plug by breaking the weakened portion. With the outer cylinder being torn 
away from the inner plug, the side wall is no longer pushed by the 
reinforcing ring. Therefore, the inner plug can be removed from the mouth 
of the container without using any special tool. As described above, this 
container closure can be separated easily from the container at the time 
of disposal. Besides, the container closure offers tamper-evidence since 
the inner plug is removed from the mouth of the container after the outer 
cylinder is torn away from the inner plug. 
However, the former container closure, i.e., the container closure of 
Japanese Utility Model Laid-Open No. 59247/1994 does not offer 
tamper-evidence. That is, the container closure is removed by breaking 
neither the cylinder formed integrally with the cap nor the cap body. 
Therefore, even if the container closure that was once removed from the 
mouth of the container is fitted again to the mouth of the container, this 
fact cannot at all be recognized by a third person. Furthermore, this 
container closure is constituted by the two molded articles, i.e., 
constituted by the cap body and the cylinder formed integrally with the 
overcap. Therefore, the container closure cannot be produced by one time 
of molding. Besides, the two molded articles that are produced must be 
coupled together, leaving a problem of low productivity. 
Furthermore, the latter container closure, i.e., the container closure 
disclosed in Japanese Utility Model Laid-Open No. 9751/1995 is constituted 
by three molded articles of an inner plug molded integrally with the outer 
cylinder, an overcap and a reinforcing ring, and can be produced very 
inefficiently even compared with the former container closure. Besides, 
the inner plug formed integrally with the outer cylinder has a complex 
triple-wall structure consisting of inner ring, side wall and outer 
cylinder. In addition, a separately molded reinforcing ring must be fitted 
between the side wall and the outer cylinder. Accordingly, the metal mold 
becomes complex, and the inner plug that is molded must have a high 
dimensional precision. Moreover, there remains a probability in that the 
reinforcing ring falls down prior to effecting the capping operation, 
which is a serious defect from the standpoint of production. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide a hinged cap 
which is free from the defects of the above-mentioned conventional 
container closures, can be easily separated from the container at the time 
of disposal, offers excellent tamper-evidence, easily molded and produced, 
and is effectively prevented from being broken at the time of capping. 
According to the present invention, there is provided a hinged cap, 
comprising: 
a cap body including a top plate portion and a skirt portion, the top plate 
portion having a flow-out port or having a portion for forming the 
flow-out port, the skirt portion having a protrusion formed on the inner 
surface thereof to engage with the mouth of a container; 
an outer cylinder formed integrally with said cap body so as to cover the 
outer surfaces of said cap body and said skirt portion; and 
an upper closure coupled by a hinge to the upper end portion of said outer 
cylinder; 
wherein the skirt portion of said cap body is provided with a plurality of 
slits extending in the axial direction maintaining a distance in the 
circumferential direction, the skirt portion of said cap body and said 
outer cylinder are separated away from each other via cut surfaces but are 
formed integrally together via a plurality of breakable bridge portions 
and are formed on the upper side or on the lower side of the cut surfaces, 
and the outer surface of the skirt portion of the cap body and the inner 
surface of the outer cylinder are intimately contacted to each other at 
the cut surfaces in a state where at least the cap body is fitted to the 
mouth of the container. 
In the hinged cap of the present invention, it is desired that the 
peripheral edge of the upper surface of the top plate portion of the cap 
body is provided with a small peripheral protrusion, and the inner surface 
of the upper closure has a horizontal surface that comes into contact with 
the upper end of the peripheral protrusion. 
When the top plate portion of the cap body has a portion for forming the 
flow-out port, it is desired that the portion is provided with a tab for 
opening. 
In the hinged cap of the present invention, the outer cylinder protects the 
skirt portion of the cap body at the time of capping. In a state where the 
mouth of the container is closed, the outer cylinder comes into intimate 
contact with the outer surface of the skirt portion of the cap body via 
cut surfaces to maintain the sealing. At the time of opening the cap, the 
outer cylinder is pushed up or pushed down to break the breakable bridge 
portions, so that the outer cylinder is removed integrally with the upper 
closure. With the outer cylinder being removed, the skirt portion of the 
cap body can be easily separated from the mouth of the container without 
using any tool. 
The hinged cap of the type in which the top plate portion of the cap body 
has a portion for forming the flow-out port, offers good tamper-evidence. 
It is very important that the cap of the present invention comprises the 
cap body, outer cylinder and upper closure that are molded integrally. 
That is, the upper closure is coupled by a hinge to the outer cylinder 
which is molded integrally with the skirt portion of the cap body via the 
breakable bridge portions. Therefore, the cap of the present invention is 
produced through substantially a single molding step featuring a very high 
productivity. 
Furthermore, the skirt portion of the cap body is provided with a plurality 
of slits extending in the axial direction maintaining a distance in the 
circumferential direction. When the outer cylinder is removed, therefore, 
the skirt portion outwardly expands in the radial direction, facilitating 
the removal of the cap body from the mouth of the container. 
According to the present invention, furthermore, the skirt portion of the 
cap body and the outer cylinder are separated from each other via cut 
surfaces but are molded integrally together via the breakable bridge 
portions on the upper side or on the lower side of the cut surfaces. 
Besides, the outer surface of the skirt portion of the cap body is brought 
into intimate contact with the inner surface of the outer cylinder at the 
cut surfaces. 
That is, with the skirt portion and the outer cylinder being intimately 
contacted at the cut surfaces, the skirt portion of the cap body is hooped 
by the outer cylinder in a state where the mouth is at least sealed; i.e., 
the skirt portion is prevented from outwardly expanding, and the mouth of 
the container is reliably sealed. This is particularly important in the 
case of the cap of the present invention in which the skirt portion is 
provided with slits extending in the axial direction. That is, the slits 
in the skirt portion work to weaken the engagement between the mouth of 
the container and the protrusion of the skirt portion. With the skirt 
portion being hooped by the outer cylinder, however, strong and reliable 
engagement is accomplished. 
A plurality of breakable bridge portions are provided on the upper side or 
on the lower side of the cut surfaces to couple the skirt portion of the 
cap body to the outer cylinder. Therefore, slits in the cut surfaces do 
not adversely affect the bridge portions. At the time of capping 
operation, furthermore, the outer surface of the skirt portion of the cap 
body comes into intimate contact with the inner surface of the outer 
cylinder at the cut surfaces. Therefore, the external force is prevented 
from acting on the breakable bridge portions, and the bridge portions are 
protected during the capping operation. 
The small peripheral protrusion is formed at the peripheral edge on the 
upper surface of the top plate of the cap body, and the horizontal surface 
is formed on the inner surface of the top closure over the whole periphery 
to come into contact with the upper end of the peripheral protrusion when 
the upper closure is closed. During the capping operation or when the cap 
is being conveyed or supplied, therefore, the peripheral protrusion works 
as a stopper, and the pressure acting on the upper closure is received by 
the peripheral protrusion. Accordingly, the external force is more 
effectively prevented from acting upon the bridge portions, and the bridge 
portions are perfectly protected. 
When the outer cylinder is pushed up or pushed down, furthermore, deviation 
takes place between the outer cylinder and the skirt portion on the cut 
surfaces, and the bridge portions coupling the cap body to the outer 
cylinder are cut due to the shearing force. Slits are formed in the skirt 
portion of the cap body. When the outer cylinder is removed from the skirt 
portion, therefore, the skirt portion is allowed to expand outwardly in 
the radial direction. Accordingly, the cap body can be easily separated 
away from the mouth of the container, and the mouth of the container can 
be easily opened without using any tool. 
The outer cylinder that is removed proves that the cap body has already 
been removed from the mouth of the container. Therefore, the hinged cap of 
the type in which the top plate portion of the cap body has a portion for 
forming the flow-out port, offers improved tamper-evidence owing to the 
outer cylinder. 
According to the present invention, the skirt portion of the cap body, 
outer cylinder and upper closure are injection-molded or 
compression-molded integrally and, then, a slit is formed by using a 
cutter or the like between the skirt portion of the cap body and the outer 
cylinder, and the portions except the bridge portions are separated from 
each other. Therefore, the cap can be easily produced by molding using an 
ordinary metal mold which comprises a core and a cavity. 
In the present invention, furthermore, the skirt portion of the cap body 
and the outer cylinder can be coupled together through the bridge portions 
as well as through a coupling portion that cannot be broken. In this case, 
the outer cylinder and the cap body can be removed together from the mouth 
of the container after the bridge portions have been broken. Furthermore, 
a weakened line can be formed in the outer cylinder upwardly extending 
from the lower end thereof. The outer cylinder can be easily removed by 
breaking along the weakened line.

PREFERRED EMBODIMENTS OF THE INVENTION 
The invention will now be described in detail with reference to the 
accompanying drawings. 
Referring to a side sectional view (FIG. 1) illustrating a hinged cap 
according to an embodiment of the present invention, a view (FIG. 2, 
wherein the diagram is a top view, the diagram B is a side view and the 
diagram C is a bottom view) illustrating a state where the upper closure 
of the hinged cap of FIG. 1 is opened, and a side sectional view (FIG. 3) 
illustrating a state where the hinged cap is fitted to the mouth of the 
container, the hinged cap of the present invention roughly comprises a cap 
body 1, an outer cylinder 2 connected thereto, and an upper closure 4 
coupled by a hinge 3 to the upper end of the outer cylinder 2. As will be 
understood from FIGS. 1 and 2, the upper closure 4 is turned and closed to 
completely cover the cap body 1 (FIG. 1) and is turned and opened, so that 
the cap body 1 is exposed (FIG. 2). Then, a tab 13 is torn away, and a 
liquid contained in the container is poured out. The cap body 1 comprises 
a top plate portion 5 and a skirt portion 6 hanging down from the outer 
periphery thereof. 
FIG. 4 illustrates a state where the outer cylinder 2 and the upper closure 
4 are removed from the cap body 1 that is fitted to the mouth 50 of the 
container. 
As best shown in FIG. 3, a protrusion 7 is formed along the inner periphery 
of the skirt portion 6 to come into engagement with a recessed portion 51 
of the outer peripheral side of the mouth 50 of the container, so that the 
mouth 50 of the container comes into intimate contact with the inner 
surface of the upper plate portion 5 to accomplish the sealing. In this 
embodiment, furthermore, an inner ring 8 is formed on the inner surface of 
the upper plate portion 5 to come into engagement with the inner 
peripheral side of the mouth 50 of the container, whereby the sealing is 
accomplished even on the inner peripheral side of the mouth 50 of the 
container to accomplish more reliable sealing. 
Referring to FIGS. 1 and 3, furthermore, the upper plate portion 5 of the 
cap body 1 has a portion 11 for forming a flow-out port is formed by a 
score 10. The portion 11 is provided with a tab 12 for opening. When the 
opening tab 12 is pulled, the score 10 is broken, the flow-out port is 
formed in the portion 11, and the liquid contained in the container is 
poured out through the flow-out port. Here, it is desired that the opening 
tab 12 is provided with a knurled protrusion 13 for preventing the 
slipping, so that it can be easily pulled by hand. 
A peripheral protrusion 14 is formed on the outer surface of the top plate 
portion 5 so as to surround the portion 11 for forming the flow-out port. 
In pouring out the liquid, the peripheral protrusion 14 works as a guide 
so that the liquid is smoothly poured out. 
On the inner surface of the upper closure 4 is formed a peripheral 
downwardly oriented protrusion 15 which, when the upper closure 4 is 
closed, comes into intimate contact with the inner peripheral surface of 
the peripheral protrusion 14. That is, even in a state where the flow-out 
port has been formed in the portion 11, the port is completely closed when 
the upper closure 4 is closed to maintain favorable sealing. Referring to 
FIGS. 1 and 2(A), it is desired that the peripheral protrusion 14 
surrounding the portion 11, is tall along a half peripheral portion 14a on 
the side opposite to the side where the outer cylinder 2 and the upper 
closure 4 are coupled together by the hinge 3, and is short along a half 
peripheral portion 14b on the side of the hinge 3. This is because, when 
the upper closure 4 is closed, the peripheral downwardly oriented 
protrusion 15 formed on the upper closure 4 smoothly enters into the 
peripheral protrusion 14 when the upper closure 4 is closed, and the turn 
of the upper closure 4 is not hindered. Besides, the content is poured out 
from the side opposite to the hinge-coupling portion 3, and the function 
of the peripheral protrusion 14 for guiding the pouring is not impaired. 
The outer cylinder 2 is so provided as to cover the outer peripheral 
surface of the skirt portion 6. As best shown in FIG. 4, the skirt portion 
6 of the cap body 1 covered with the outer cylinder 2 is provided with a 
plurality of slits 20 extending in the axial direction maintaining a 
distance in the circumferential direction. 
The skirt portion of the cap body 1 and the outer cylinder 2 are separated 
from each other via circumferential cut surfaces. The skirt portion 6 and 
the outer cylinder 2, however, are molded integrally together via a 
plurality of breakable bridge portions 22 on the upper side of the cut 
surfaces 21. FIG. 2A clearly shows the bridge portions 22, and FIG. 4 
shows the bridge portions 22 that are remaining as designated at 22' on 
the skirt portion 6 and on the outer cylinder 2 (which has been removed 
from the cap body 1). 
The outer surface of the skirt portion 6 of the cap body and the inner 
surface of the outer cylinder 2 are intimately contacted to each other at 
the cut surfaces 21 in a state (FIG. 3) where the cap body 1 is sealing 
the mouth 50 of the container. 
When the bridge portions 22 are broken to separate the outer cylinder 2 
from the cap body 1, the skirt portion 6 outwardly expands due to the 
action of the plurality of slits 20 formed in the skirt portion 6 of the 
cap body 1 and extending in the axial direction. Therefore, the recessed 
portion 51 on the outer peripheral side of the mouth 50 of the container 
is disengaged from the inwardly facing protrusion 7 of the skirt portion, 
and the cap body 1 is easily removed from the mouth 50 of the container. 
The number of the slits and their interval in the circumferential 
direction are suitably determined from the above-mentioned points. 
In the cap of the present invention, it is desired that the skirt portion 6 
is provided with the slits 20 in a number of, usually, 2 to 20 and, 
particularly, 8 to 12 though it may vary depending upon the diameter of 
the cap. 
With the skirt portion 6 and the outer cylinder 2 being intimately 
contacted to each other at the cut surfaces 21, the skirt portion 6 of the 
cap body is hooped by the outer cylinder 2 in a state where the cap body 1 
is fitted to the mouth 50 of the container, the skirt portion 6 is 
prevented from outwardly expanding, and the mouth 50 of the container is 
reliably sealed. In the case of the cap of the present invention in which 
the skirt portion 6 is provided with the slits 20 that are extending in 
the axial direction, the intimately contacted state plays a particularly 
important role. That is, the slits 20 in the skirt portion 6 work to 
weaken the engagement between the recessed portion 51 formed along the 
outer periphery of the mouth 50 of the container and the protrusion 7 of 
the skirt portion 6. With the hooping force of the outer cylinder 2 
working thereon, however, a strong and reliable engagement is obtained. 
In FIGS. 1 to 4, the skirt portion 6 of the cap body and the outer cylinder 
2 are coupled together through breakable bridge portions 22 only. When the 
upper closure 4 coupled by the hinge to the outer cylinder 2 is pulled up 
or pushed down by fingers, therefore, deviation takes place between the 
outer cylinder 2 and the skirt portion 6 on the cut surfaces 21, and the 
bridge portions 22 coupling the cap body 1 to the outer cylinder 2 are 
easily broken by the shearing force. 
FIG. 4 illustrates a state where the outer cylinder 2 is separated from the 
cap body 1 that is fitted and secured to the mouth 50 of the container. 
The skirt portion 6 of the cap body has been provided with the slits 20. 
When the outer cylinder 2 is removed from the skirt portion 6, therefore, 
the skirt portion 6 is allowed to outwardly expand in the radial 
direction, and the cap body can be easily separated and removed from the 
mouth 50 of the container without using any tool. In FIG. 4, reference 
numeral 22' denotes the bridge portions 22 after broken. 
According to the present invention as described above, the cap after used 
can be separated from the container and disposed of easily. 
The number and positions of the bridge portions 22 provided between the 
skirt portion 6 of the cap body and the outer cylinder 2 may be such that 
the bridge portions 22 are not broken during the capping operation and 
that the bridge portions 22 are easily broken when it is attempted to 
remove the cap body 1 from the mouth 50 of the container (i.e., when the 
cap is to be discarded), enabling the outer cylinder 2 to be quickly 
separated away from the skirt portion 6. In this sense, there is no 
particular limitation on the positions and number of the bridge portions. 
In general, it is desired that each bridge portion 22 has a sectional area 
of 0.1 to 1.5 mm.sup.2 and, particularly, 0.2 to 1.0 mm.sup.2 in the 
direction of cut surfaces 21 (axial direction of the cap). In the 
embodiment of FIGS. 1 to 4, the bridge portions 22 are provided on the 
upper side of the cut surfaces 21. However, the bridge portions 22 may be 
arranged on the lower side of the cut surfaces 21. 
In the above-mentioned cap, the top plate portion 5 of the cap body 1 has 
the portion 11 for forming the flow-out port. The upper closure 4 is 
turned and is opened, and the content is poured out through the flow-out 
port formed in the portion 11 by breaking the score 10. The cap of this 
type offers very good tamper-evidence. That is, to remove the cap body 1 
from the mouth 50 of the container, the outer cylinder 2 must be separated 
away from the cap body. In the cap of this type, therefore, the outer 
cylinder 2 that is separated proves that the cap is removed from the mouth 
50 of the container even though the flow-out port has not been formed in 
the portion 11. 
The present invention is in no way limited to the cap of the 
above-mentioned type only but can also be applied to the caps of, for 
example, the type in which the flow-out port has been formed from the 
beginning in the outer surface of the top plate portion 5 of the cap body 
1. In this case, there is no improvement in the tamper-evidence, but the 
above-mentioned separability and sealing are accomplished to a 
satisfactory degree. 
In the present invention as clearly shown in FIGS. 1 and 3, it is desired 
that the small peripheral protrusion 30 is formed at the peripheral edge 
on the upper surface of the top plate portion 5 of the cap body, and a 
horizontal surface 31 is formed on the whole inner peripheral surface of 
the upper closure 4 so as to come into engagement with the peripheral 
protrusion 30 when the upper closure 4 is closed. In the cap of the 
present invention, the skirt portion 6 of the cap body and the outer 
cylinder 2 are coupled integrally through the breakable bridge portions 
22. During the capping operation and when the cap is conveyed and 
supplied, therefore, it is likely that the load in the axial direction may 
be concentrated on the bridge portions 22 causing the bridge portions 22 
to be broken. With the peripheral protrusion 30 and the horizontal surface 
31 being formed as described above, however, the peripheral protrusion 30 
works as a stopper which receives the load in the axial direction exerted 
on the upper closure 4. Therefore, the pressure is effectively prevented 
from being concentrated on the bridge portions 22 that can be easily 
broken, and the bridge portions 22 are perfectly protected. 
According to the present invention, it is essential that the lower end 2a 
of the outer cylinder 2 is extending up to the recessed portion 51 on the 
outer peripheral side of the mouth 50 of the container. That is, when the 
lower end 2a is not extending up to the recessed portion 51, the skirt 
portion 6 of the cap body is not tightened by the outer cylinder 2 to a 
sufficient degree, and satisfactory sealing is not maintained. Moreover, 
so far as the outer cylinder 2 has such a size, the lower end of the outer 
cylinder 2 may be located at a position lower than the lower end of the 
skirt portion 6 of the cap body as shown in FIG. 3, or may be located at a 
position nearly horizontal relative to the lower end of the skirt portion 
6 of the cap body, or may be located at a higher position. 
According to the above-mentioned embodiment, the bridge portions 22 are 
provided on the upper side of the cut surfaces 21. As briefly mentioned 
above, however, the bridge portions 22 may be provided on the lower side 
of the cut surfaces 21. From the standpoint of productivity, however, it 
is desired that the bridge portions 22 are provided on the upper side of 
the cut surfaces 21. 
As the resin for molding the cap, there can be used a variety of plastics 
such as low-, medium or high-density polyethylene, linear low-density 
polyethylene, polypropylene, thermoplastic polyester, polyamide, styrene 
resin, ABS resin and the like resins. 
By using the above-mentioned resin, the hinged cap of the present invention 
is obtained in a state where the cap body 1, outer cylinder 2 and upper 
closure 4 are integrally molded together by injection molding or 
compression molding. After this molding step, cutting is performed between 
the cap body 1 and the outer cylinder 2 by using a cutter or the like to 
form cut surfaces 21 in the portions except the bridge portions 22, so 
that the two are separated from each other. When the bridge portions 22 
are to be provided on the upper side of the cut surfaces 21, cutting is 
performed by inserting the cutter or the like from the lower side of the 
cap. When the bridge portions 22 are to be provided on the lower side of 
the cut surfaces 21, the cutter or the like is inserted from the upper 
side of the cap in a state where the upper closure 4 is opened. 
As described above, the cap of the present invention can be produced 
efficiently and within short periods of time in the flow of a 
substantially single molding step by using an ordinary metal mold 
comprising a core and a cavity maintaining very high productivity and high 
precision at each of the portions of the cap, suppressing the formation of 
defective products. 
It is of course allowable to form the bridge portions 22 and the cut 
surfaces 21 simultaneously in the above step of molding. During the 
molding, in this case, the cap body 1 and the outer cylinder 2 are not 
intimately contacted to each other at portions where the cut surfaces 21 
are formed. In the state where the cap body 1 is fitted to the mouth 50 of 
the container, however, the skirt portion 6 of the cap body are outwardly 
expanded and, hence, the cap body 1 and the outer cylinder 2 are 
intimately contacted to each other via the cut surfaces 21. 
It is also possible to form the slits 20 at a subsequent step after the 
step of integral molding. 
According to another embodiment of the present invention shown in FIG. 5, 
the outer cylinder 2 is provided with a weakened line 40 to facilitate the 
removal of the outer cylinder 2. As will be obvious from FIG. 5, the 
weakened line 40 extends in the axial direction of the outer cylinder 2 
and has a notch 41 formed at the upper end thereof. That is, the outer 
cylinder 2 is torn away by breaking the weakened line 40 starting from the 
notch 41. The outer cylinder 2 that is torn away is torn off in the 
circumferential direction, whereby the bridge portions 22 are broken, and 
the outer cylinder 2 is very easily removed from the cap body 1. The 
weakened line is, usually, a score but may be a perforation. 
It is generally desired that the score is formed on the outer surface of 
the outer cylinder 2. 
The notch 41 may be formed at the lower end of the weakened line 40. 
In the above-mentioned embodiment of FIG. 1, the outer cylinder 2 and the 
skirt portion 6 of the cap body are coupled integrally through the 
breakable bridge portions 22 only. It is, however, also possible to form a 
coupling portion that cannot be broken between the two together with the 
bridge portions 22. This embodiment is shown in FIG. 6 which is a top view 
of the hinged cap in a state where the upper closure is opened, wherein a 
coupling portion is provided as designated at 45. The coupling portion 45 
is wider than the bridge portions 22 and cannot be easily broken. If the 
outer cylinder 2 is turn off with the coupling portion 45 as a fulcrum, 
the bridge portions 22 are broken and the skirt portion 6 is liberated 
from the hooping force. By pulling up the outer cylinder 2 formed 
integrally with the upper closure 4 in this state, therefore, the cap body 
1 can, at the same time, be removed from the mouth 50 of the container. 
The coupling portion 45 can be easily formed by so effecting the cutting 
for forming the cut surfaces 21 as to leave the bridge portions 22 and the 
coupling portion 45. 
When the coupling portion 45 is to be formed in the hinged cap of FIG. 5, 
it is desired to form the coupling portion 45 at a position away from the 
break-starting portion (notch 41) of the weakened line 40. 
The cap of the present invention can be efficiently produced through a 
series of molding steps maintaining a very high productivity. 
In the capped and sealed state, the skirt portion of the cap body is 
intimately contacted to the mouth of the container being tightened by the 
outer cylinder to establish a reliable sealing structure. The cap can be 
easily removed from the mouth of the container without using any 
particular tool. Therefore, the cap after used can be separated easily 
from the container at the time of disposal. 
Besides, the cap of the type having a portion where the port will be formed 
offers excellent tamper-evidence.