Safety closure

A safety closure, particularly safe in the hands of children, to safely close containers composed of an assembly of an inner cap and an outer cap, the inner cap provided with threading for screwing onto the mouth of a container. The outer cap can be depressed over the inner cap against a resilient force provided by lips coating with a conical surface. When depressed, teeth on the outer cap mesh with teeth on the inner cap to effect unscrewing of the closure. A ratchet provided by teeth on the inner cap cooperating with tangential protrusions on the outer cap enable onscrewing of the closure but prevent offscrewing.

The invention relates to a safety closure, particularly safe in the hands 
of children, to safely close containers. 
BRIEF SUMMARY OF THE INVENTION 
The closure comprises an assembled combination of an inner cap housed in 
and surrounded by an outer cap and whereby the inner cap is provided at 
its top side with a central closed cylindrical portion and a surrounding 
external skirt portion which comprises at its inner side a threaded 
portion which serves to screw the closure upon the mouth of a container. 
The external skirt portion is connected with said cylindrical portion 
integrally by means of an intermediate wall portion comprising a conical 
part. The outer cap is provided with a top wall end portion, having a 
central opening to cooperate with the closed cylindrical portion of the 
inner cap. The outer cap also has a cylindrical skirt portion which 
extends from the edges of the top wall end portion and the outer cap is 
guided by coacting in a sliding relation with the central closed 
cylindrical portion of the inner cap. The top wall end portion of the 
outer cap comprises inwardly extending flexible lips which point inwardly 
in the space created between the central closed cylindrical portion of the 
inner cap and the intermediate wall portion of the inner cap. The lips 
cooperate with the conical portion of the intermediate wall portion in 
such manner that when the outer cap of the closure is not being pressed 
down, the upper part of the central closed cylindrical portion on the 
inner cap and the top end wall portion of the outer cap, substantially lie 
in the same plane by virtue of the resilient interaction between the lips 
and the conical portion. When a downward pressure is exerted on the outer 
cap, the outer cap slides relative to the inner cap being guided by the 
coaction between the central closed cylindrical portion and the outer cap. 
During this time the lips engage and are guided along the conically shaped 
intermediate wall portion on the inner cap. The external skirt portion of 
the inner cap is provided with radial rib-shaped teeth which engage with 
radial rib-like teeth formed on the cylindrical skirt portion of the outer 
cap when the outer cap has slid axially relative to the inner cap by a 
predetermined distance. The surface of the intermediate wall portion on 
the inner cap which is facing the central closed cylindrical portion is 
provided with radial rib-shaped teeth, whereas each of the inwardly 
protruding lips on the outer cap is provided with a tangentially extending 
protrusion having a length in the axial direction which is less than the 
length of said lips, but of such length that these protrusions interengage 
the rib-like teeth on the inner cap both when no pressure is exerted upon 
the outer cap of the closure and when pressure is exerted on the outer cap 
and it has moved axially relative to the inner cap to its full extent; 
that is, to the point the first mentioned radial rib-shaped teeth are 
engaged. 
BACKGROUND OF THE INVENTION 
From a prior development a safety closure is known, published Nov. 25, 1982 
in the international patent application No. PCT/EP82/00100, which has the 
feature of an interengagement effected between radial rib-shaped teeth on 
the inner surface of the skirt portion of the outer cap with radial 
rib-shaped teeth provided on the outer surface of the skirt portion of the 
inner cap and whereby exerting a downward pressure upon the outer cap and 
against spring operation of lips engaged with a conical surface and by a 
simultaneously effected rotational movement of the outer cap, a 
co-rotation of the inner cap is caused which enables onscrewing or 
unscrewing of the safety closure. 
A disadvantage for onscrewing of this prior closure upon a container mouth 
is the requirment to press down the outer cap for interengaging the inner 
and outer caps before rotation of the outer cap can be transmitted to the 
inner cap. The user must thus be informed of the instruction "press down" 
(for onscrewing) and he must repeatedly keep in his mind while onscrewing 
the closure to press it down initially and to maintain it pressed down. 
It is the object of the invention to improve the prior closure as described 
before in such a manner as to avoid the necessity of providing 
instructions for onscrewing and to enable the user to easily onscrew 
without any special instructions or considerations. 
According to the present improvement and invention a safety closure of the 
aforementioned type is especially constructed and characterized in that 
the surface of the intermediate wall portion on the inner cap which is 
facing the cylindrical portion is peripherally spaced, provided with 
radial rib-shaped teeth whereas each of the inwardly protruding 
circumferentially spaced lips on the outer cap is provided on its surface 
facing the intermediate wall portion with a tangentially extending 
protrusion having a length in the axial direction which is less than the 
length of said lips, but great enough for these protrusions to interengage 
the radial, rib-shaped teeth on the inner cap in all relative positions of 
the two caps. That is, whether pressure is being exerted upon the outer 
cap of the closure or not. 
By this novel invented safety closure, the provision of the described 
additional teeth creates an interengagement even at no downward pressure 
on the outer cap and this ensures a more powerful cooperation between the 
inner and outer caps.

DETAILED DESCRIPTION 
From the figures of the drawing, the safety closure generally designated by 
reference numeral 1 in FIG. 1 and FIG. 2 comprises combined outer cap 2 
and inner cap 3 loosely assembled as will be explained in detail 
hereinafter. The inner cap 3 and outer cap 2 are molded from suitable, 
safe for human use, plastic materials, in a manner known in the art. The 
outer cap 2 is provided with a top end wall portion 4 in which a central 
opening 5 is located. A cylindrical skirt portion 6 depends from the outer 
peripheral edge of the end wall portion 4. 
The inner cap 3 comprises a central cylindrical portion 7, closed at its 
top 7a, and an external skirt portion 8, which is provided with integrally 
molded screw threads 9 to enable the closure to be mounted onto the mouth 
of a container having complementary screw threads, all as well known in 
the art. The external skirt portion 8 is integrally connected, by means of 
an intermediate wall portion 11 including a conical portion 10, with the 
cylindrical portion 7. The wall forming the opening 5 in top end wall 
portion 4 of outer cap 2 engages and is guided by the cylindrical portion 
7 on the inner cap 3, when the outer cap 2 is pressed downwardly relative 
to inner cap 3. 
The end wall portion 4 of the outer cap 2 is provided with inwardly 
extending resilient or springy lips 12, at least two and preferably not 
more than four, which point or depend into the space created between the 
cylindrical portion 7 and the intermediate wall portion 11 of the inner 
cap 3. The lips 12 coact with and cooperate with the inner surface of 
conical portion 10 of this intermediate wall portion 11 in such a manner 
that in the unstressed or repose condition of the safety closure 1 (no 
downward pressure on outer cap 2), the top side 7a of the cylindrical 
portion 7 on the inner cap 3 and the top end wall portion 4 of the outer 
cap 2 are kept or held in substantially the same plane by the bias or 
spring operation or interaction of the lips 12 against the conical portion 
10. In case a pressing force is effected upon the outer cap 2, these lips 
12 are guided along the conical portion 10 of the intermediate wall 
portion 11 on the inner cap 3 and are flexed inwardly increasing the bias 
to restore the outer cap 2 to the condition shown in FIG. 2, to which cap 
2 will return when the pressing force is released. 
The outer surface 13 of skirt portion 8 of the inner cap 3 is provided with 
peripherally spaced, radial rib-like teeth 14, pointing substantially 
radially, which cooperate and interengage, respectively, with peripherally 
spaced, radial rib-like teeth 16 formed on the inner surfaces of 
cylindrical skirt portion 6 and end wall portion 4. Teeth 14 and 16 will 
engage when outer cap 2 has slid axially downwardly a predetermined 
distance relative to inner cap 3. This occurs against the bias or pressing 
force exerted upwardly upon the outer cap 2 by the spring or resilient 
force of the lips 12 as they are deflected due to following the conical 
portion 10. 
The surface 17 of the intermediate wall 11 which faces inwardly toward the 
cylindrical portion 7 is provided at its upper end with radially 
extending, peripherally spaced, rib-like teeth 18. The lips 12 on the 
outer cap 2 are each provided with a tangential protrusion 19, having a 
length in the axial direction less than the axial length of the lips 12. 
These protrusions 19 are curved into the region or plane of teeth 18 and 
are interengaging with the teeth 18 both in the condition shown in FIG. 2 
and when downward pressure is exerted upon outer cap 2 of the closure to 
effect interengagement of teeth 14 and 16. The combined closure can thus 
be onscrewed upon a container mouth by the protrusions 19 of the lips 12 
which provide a sufficient rigidity in a tangential direction to 
interengage with teeth 18. In the direction reverse to onscrewing, namely, 
the offscrewing direction, the protrusions 19 provide sufficient 
flexibility that upon turning of the outer cap 2 in this reverse 
direction, the protrusions 19 slide past the teeth 18, due to their 
flexibility, thereby causing a rattling noise, informing the user by an 
audible signal to initiate some activity for unscrewing the closure. The 
teeth 18 and protrusions 19 have the effect of a ratchet, allowing 
onscrewing but preventing offscrewing except when outer cap 2 is pushed 
down. The user must achieve offscrewing by pressing down the outer cap 2, 
thereby causing interengageent of the teeth 16 of the outer cap 2 with the 
teeth 14 of the inner cap 3 after which the closure can be unscrewed and 
removed from the mouth of the container. 
For loosely keeping the outer and inner caps assembled, the outer cap is 
provided at its open bottom with a rim 20 extending radially and which 
overlaps an outer rim 21 provided on the inner cap. The inner and outer 
caps are manufactured from material with elastic properties, particularly 
from plastic material, and accordingly, the inner and outer caps are 
easily mountable and demountable, respectively, by elastic deformation. 
In a preferred embodiment the central opening 5 of the top wall portion 4 
of the outer cap 2 is protected, covered or locked by a wall portion 22 
which is connected to top wall portion 4 by a tearable or rupturable 
connection 23. This tearable wall portion 22 can be used as a guarantee 
seal for guaranteeing the kind, quality and quantity of the container 
content for newly filled containers. Wall portion 22 needs to be removed 
to actuate the sliding relationship between inner cap 3 and outer cap 2 to 
effect opening of the closure.