EP0078292B1

EP0078292B1 - Safety closure containers

Info

Publication number: EP0078292B1
Application number: EP82901509A
Authority: EP
Inventors: Henricus Antonius Maria Bekkers
Original assignee: Technoplast BV
Current assignee: Technoplast BV
Priority date: 1981-05-11
Filing date: 1982-05-11
Publication date: 1986-10-29
Also published as: AU576732B2; GB2131776A; EP0078292A1; GB2131776B; NL8102296A; SE8303329L; SE450246B; DK245583D0; SE8303329D0; WO1982004029A1; AU8450482A; DK245583A; GB8400716D0; DE8234933U1; DE3246013T1; NO832439L

Abstract

A safety closure for containers comprises an assembled combination of an inner cap (103) housed in and surrounded by an outer cap (102). The inner cap (103) is provided along its outer circumferential surface or skirt portion (104) with a series of first teeth (106), the inner depending skirt portion of the outer cap (102) is provided with a series of second teeth (107) which can be brough in engagement with the first said teeth (106) by means of a relative coaxial movement of the inner and outer caps. The safety closure can be unscrewed from the container or screwed upon the mouth of the container respectively only by exerting upon the outer cap (102) a downward pressure causing the said teeth (106 and 107) to become interengaged, whereafter the inner cap (103) can be turned. The downward pressure upon the outer cap is resiliently resisted by means of spring elements or lips (118) depending from the upper wall portion (113) of the outer cap (102) which lips (118) are flexing against a wall portion (110) of the inner cap (103) which is located inside the container mouth and which converges annularly. The inner cap (103) is provided with a central cylindrical portion (111) rising up from said annulus (114), said lips (118) being operable in the space between the said cylindrical portion (111) and the inner mouth portion of the inner cap. Said central upper surface (112) of the inner cap (103) being rigidly and integrally connected to the remaining inner cap portion (110) in such a manner as to resist weight loads placed upon the safety closure even if the outer cap surface (113), surrounding the said central portion (112) may be slightly depressed thereby. The surface of said central cylindrical portion (111) being shaped as a central guide to the surrounding edge portion of the outer cap (102) during its coxial movement if downward pressure is exerted. It is preferred to have the surfaces of the upper portions (112, 113) of the inner and outer caps (103, 102) lying in nearly the same horizontal plane to render the safety closure a one piece outlook.

Description

This invention relates to safety closures for containers which can be readily applied and removed by one having knowledge of their operation, and which are relatively safe in the hands of children because they are usually unable to manipulate the closures in the required manner to remove them from the containers.
Safety closures of the described type have been in use for drug containers but in view of stringent government product safety regulations are increasingly desirable for containers closures containing more or less aggressive liquids dangerous to children. In every normal household such containers or bottles frequently appear and are to be opened and closed many times more than is the case with drug containers. The latter moreover are mostly less easily reachable for children and usually are kept away more safely.
Usually plastic bottles contain aggressive liquids, such as e.g. chlorine bleaching water. Production methods for such bottles cannot avoid the irregularities around the neck opening of these bottles, thereby creating sometimes serious difficulties because of liquid crystallization as a result of leakage. If the space between an inner and outer cap of an existing safety closure would be filled with crystals, the safety aspect of the closure would be endangered as this could unexpectedly cause an engagement between the several parts of the closure, enabling unauthorized removal thereof.
In particular, a safety closure according to the invention is of a type as indicated in the introductory statement of the attached claim 1, which type is known as such from FR-A-2 079 409, in particular Fig. 8. This publication shows a bayonet joint between inner and outer cap, the lips and the recessed space being provided in an axial zone of the closure separate from and above the container fastening means on the inner cap, which, as usual, consisted of an internal screw-threaded part in the inner cap.
This requires an axially long closure, requiring more material and more height, which is a disadvantage in stacking closed containers one on top of the other for transporting and storing purposes.
From US-A-3 782 604 a safety closure of about the same type is known, which is much shorter by having short resilient lips diverging downwardly from their connection to the top terminal wall of the outer cap and resting resiliently on the top terminal wall of the inner cap. Particularly for small closures this has the disadvantage that the lips have to give a considerable resilient force while being of short length, which causes them to rupture or lose their resiliency easily. Much longer resilient lips as in said French publication are very preferable over such short lips.
This invention aims at providing an improvement of such known safety closures, combining safety and reliability also after long periods of storing and use with a simple, inexpensive and short structure.
To this end, a safety closure according to the introductory statement of the attached claim 1 is according to the invention characterised in that the outer wall of said recessed space extends downwardly from the top of the outer skirt of the inner cap so as to allow taking up the mouth of the container in the space radially between said outer skirt and said outer wall of said recessed space.
As the outer skirts of the caps need a sufficient axial length for their safe engagement of the container, the application of the invention allows a reliable structure of the closure to have a length not more than the length of the container fastening means in the outer skirt of the inner cap plus the axial stroke of depression of the outer cap with respect to the inner cap for causing interengagement of the protruding parts to allow removal of the closure, plus the wall thickness of the terminal wall of the outer cap and the wall thickness of the inner cap where its outer skirt merges into said recessed part, notwithstanding the application of long resilient lips and a correspondingly deep recessed space in the inner cap cooperating therewith. The sealing between the container and the closure becomes much more reliable.
In said French publication the outer cap is guided on the inner cap by their closely surrounding outer skirts and by the contact between the resilient lips and the wall of the recessed space. In Fig. 8 thereof the terminal wall of the inner cap is in one plane with and engaging in a central opening of the terminal wall of the outer cap.
As the inner wall of the recessed space is conical, this central opening should be so wide as not to jam onto this conical wall when depressing the outer cap axially to allow unscrewing of the closure, so that this opening does not give much guidance of the inner cap by the outer cap in non- depressed condition of the outer cap and in the depressing movement of the outer cap. This is a disadvantage, which is removed in a preferred embodiment of the closure according to the invention by applying the features of the attached claim 2. As the recessed space according to the invention should be of the smallest possible radial extent to allow the mouth of the container to surround at least the greater part of this space, such a cylindrical central portion of the inner cap near its top end wall is also favourable for keeping this radial extent as small as possible.
Application of the invention also allows a favourable guarantee seal to be applied, which ruptures at the first attempt to depress the outer cap with respect to the inner cap, by applying the features as given in the attached claim 3.
Other objects and advantages will become apparent from the following detailed description, while referring to the attached drawings, in which:

Fig. 1 is an enlarged, perspective view of a safety closure embodying the novel features of the present invention;
Fig. 2 is a cross-sectional view taken generally along the line 11-11 of Fig. 1; the left part showing the safety closure in its norml position while no removal force or torque is applied, the right part showing the safety closure while exerting a downward pressure upon the outer cap in the direction of the arrow;
Fig. 3 shows another embodiment of the invention in a cross-sectional view similar to the left part of Fig. 2. The inner cap and the outer cap are modified;
Fig. 4 and Fig. 5 show partially a bottom view and a top view of the outer cap shown in Fig. 2 in its assembled position(s).

(The scale of the various embodiments shown may differ for purposes of clarification only.)
Turning now to Fig. 1, there is shown a safety closure 1 embodying the present invention and comprising an outer cap, indicated generally at 2, overlying an inner cap, indicated generally at 3, with the inner and outer caps being concentrically aligned.
As shown in Figs. 2,4 and 5, to fasten the safety closure 1 to a container (not shown), a generally cylindrical skirt 104 of the inner cap 103 is formed with a container fastening means such as a helical screw thread 105.
To apply the safety closure 1 by screwing the thread 105 onto the cooperatively threaded portion of a container, one or more teeth, indicated generally at 106, on the skirt portion 104 of the inner cap 103 project radially and generally coaxially outwardly for engagement with one or more teeth, indicated generally at 107, on the inner side of a depending generally cylindrically shaped skirt position 108 of the outer cap 102. The cooperating teeth 106 and 107 are shown in a vertical position. However, they may instead also be placed in a generally sloping position under say 45°. The upper portion of the inner cap 103 is further shaped in such a manner that an upper container rim is received in the circumferential space 109 created by the skirt portion 104 being turned back axially at 110. The central upper portion 111 of the inner cap 103 is of cylindrical shape and its flat top surface 112 lies nearly in the same plane as the concentrically arranged top surface portion 113 of the outer cap 102. The annular connecting portion 114 of the inner cap 103 between its skirt portion at 110 and its cylindrical top surface 112 will perfectly house and thereby seal any irregularity processed on the container neck portion to be located in the space 109, thereby avoiding any possible leakage of liquid from the container.
The lower end of the outer skirt portion on the outer cap 102 is provided with a thicker annular inwardly protruding retaining portion 116. The inner cap 103 is further provided at its lower part with an annular outwardly protruding rim 117 which, in the assembled position of both caps 102 and 103 of the safety closure 1, is retained within annular portion 116. Furthermore the outer cap 102 has a number of, preferably 6, depending, flexibly resilient lips 118, the bottom ends of which contact the conical lower part of the recessed space in the inner cap 103 at 110. The function of these lips 118 will easily be understood. They are resiliently bent somewhat inwardly by said conical wall and thus tend to keep the outer cap 102 in its highest position.
In the position of the safety closure 1 shown in the left part of Fig. 2, the inner cap 103 will be sealingly engaged with the container opening, the outer cap 102 by means of the resilient lips 118 is held in its uppermost position wherein the topmost portion of both the inner and the outer caps 103 and 102 respectively lie in the same horizontal plane. A removal torque, only exerted on the outer cap 102, will not result in unscrewing the inner cap 103 from the container since none of the teeth 106 and 107 will engage.
At the right in Fig. 2 it is shown that the resilient lips 118 are pressed down only upon the exertion of a downward pressure indicated by the arrow.. Only then the teeth 106 and 107 may become interengaged and when simultaneously a removal torque is applied to the outer cap 102, the safety closure can be unscrewed from the container. The lips 118 bend inwardly and thus give increasing resistance against such downward pressure, and they may even limit such downward movement when they reach bottom 114.
It is very important in view of the durability of the desired function of a safety closure of the type herein described, that there will be no permanent downward pressure to be exerted on the outer cap 2 which may perhaps cause damage to the lips 118 to become so much overloaded that they finally collapse due to material fatigue of the plastic material thus losing its function as a safety closure entirely. By making the central portion of the inner cap 103 with the terminal wall 112 high enough and by giving it sufficient material strength, it will e.g. be possible that a number of layers of containers can be stored above a first layer, e.g. in a box, or if packed in plastic shrinking foils, each layer being placed upon a horizontal separating sheet. Even such a way of container packing does never interfere with the desired function of the safety closure because no downward pressure is permanently during storage exerted upon the outer cap 102 by the weight of any other container to the load of other articles placed thereupon.
There is only a slight clearance between the periphery of the central portion below 112 of the inner cap 103 and the central opening in the terminal wall 113 of the outer cap 102, serving to avoid possible dirt penetrating the workable parts of the safety closure 1 and giving a good guiding of the outer cap during depression in that said central opening slides along the cylindrical portion 111 of the inner cap 103. The invented closure does not really allow for leakage of liquid because of the specially designed sealing portion on the inner cap effectively housing the container opening and if unexpectedly any liquid would become enclosed and received in the annular portion at 114, crystallization would not prevent the normal operation of the safety closure as the lips 118 will break up such crystals when being depressed. There is also shown an additional central cover disc 120 overlying the central portion 112 to give a kind of guarantee function to verify that the container has not yet been opened by unscrewing the safety closure from it. The cover disc 120 is connected to the outer cap 102 by means of e.g. three tearable ribs 121 integrally formed with the cap. Also the upper part of the outer wall of the recessed space of the inner cap at 110 is slightly conical in such a way as to guide and seal off the opening of the container perfectly into space 109, even if irregularities would appear as a result from the production method used.
Fig. 3 discloses a similar safety closure as just described, however with few differences. The mouth of the container is somewhat wider and the central cylindrical wall portion 211, long enough to guide the outer cap when it is depressed, is integrally connected to a conical lower wall portion before it continues into the connecting annular portion 214. To assist the assembling of the inner cap 203 within the outer cap 202, a conical ring portion 222 is integrally formed with the outer cap 202 to ensure a correct position of the uppermost central portion 212 of the inner cap 203 with respect to the outer cap 202. The cooperating teeth 206 and 207 respectively, the retaining ring portion 216 and the protruding rim portion 217 are accordingly shown.
In Figs. 4 and 5 the position of some parts with respect to the outer cap 102 of Fig. 2 are additionally shown in so far as the cross-sectional view does not always sufficiently disclose their location.
The safety closure according to the present invention is preferably molded from relatively hard somewhat elastic plastic materials, such as polypropylene, polyethylene or the like, depending on the various requirements relating to the container, the liquid and the duration of expected container use and the desired opening and closing forces to be applied by the average user of a container for household purposes. Such materials and the wall thickness of the closure parts may easily be chosen so as to allow some deformation in case of irregularities in shape and dimensions of usual container mouths.
Various features of the invention are set forth in the following claims.

Claims

1. A safety closure for fastening to containers, comprising: an outer cap (102, 202) having a circular top end wall (113) and a cylindrical shaped skirt (108) depending from the outer edge of said top end wall, an inner cap (103, 203) having a top end wall (112, 212) and a depending skirt (104) joined to the outer edge of said top end wall, said outer cap overlying and substantially enclosing the inner cap and being concentric therewith, container fastening means (105) on the skirt of the inner cap for releasably fastening on a portion of a container, outwardly protruding radially and vertically extending teeth (106, 206) on the external wall surface of the skirt (104) of the inner cap and inwardly protruding radially and vertically extending teeth (107, 207) on the inner wall of said outer cap skirt, there being radially protruding cooperating parts (116, 117) on the inner and outer caps to keep them in their assembled position and to allow the outer cap to be axially displaced between first and second positions relative to the inner cap, the said teeth (106, 206) on the inner cap being out of operational engagement with said teeth (107, 207) on the outer cap in the first position and interengaging operationally in the second position so that rotation of the outer cap produces a corresponding rotation of the inner cap, there being a plurality of resilient lips (118) provided on the outer cap (102, 202) and depending from the top end wall (113) thereof and arranged to cooperate with a circumferential abutment region (110) provided on the inner cap thereby resiliently loading the outer cap into its first position relative to the inner cap, said abutment region (110) on the inner cap being a bottom part of a recessed space between the top end wall (112, 212) and the skirt (104) of the inner cap, which bottom part is inclined with respect to its axis and in contact with said lips (118) on the outer cap, said recessed space having an inner wall extending axially into a central opening in the top end wall (113) of the outer cap, characterized in that the outer wall of said recessed space extends downwardly from the top of the outer skirt (104) of the inner cap so as to allow taking up the mouth of the container in the space (109) radially between said outer skirt (104) and said outer wall of said recessed space.

2. A closure according to claim 1, in which the central portion (111, 211) of the inner cap (103, 203) near its top end wall (112, 212) is cylindrical, a central opening in the top end wall (113) of the outer cap (102, 202) surrounding this cylindrical portion with small clearance to guide the outer cap (102, 202) by said cylindrical portion on its downward depression from said first to said second portion.

3. A closure according to claim 2, in which the opening in the top end wall (113) of the outer cap (102, 202) is bridged by a part (120) connected to said top end wall by an easily rupturable connection (121), which part overlies the top end wall (112, 212) of the inner cap so as to rupture when the outer cap is depressed so as to be axially moved from its first to its second position.