US3812990A

US3812990A - Safety closure assembly

Info

Publication number: US3812990A
Application number: US00285445A
Authority: US
Inventors: W Willis
Original assignee: Aluminum Company of America
Current assignee: Howmet Aerospace Inc
Priority date: 1972-08-31
Filing date: 1972-08-31
Publication date: 1974-05-28
Anticipated expiration: 1991-05-28

Abstract

A safety closure assembly is provided which includes an inner cap with threads formed in its skirt for affixation to a container by turning the cap, vertically aligned corrugations in the outer surface of the top portion of the cap skirt and an outwardly projecting bead on the lower edge of the skirt, and further including an outer flexible plastic cap which fits over the inner cap and which has inwardly projecting, vertically aligned teeth on its inner surface for engagement with the corrugations on the inner cap, an inwardly projecting flange on the bottom edge of the skirt for engagement under the bead on the inner cap to preclude separation of the caps, and an inwardlyupwardly inclined inner surface of the skirt above such flange for engagement against the outer surface of the bead on the inner cap to spring the outer cap upwardly with respect to the inner cap and thereby prevent engagement of the teeth on the outer cap with the corrugation on the inner cap unless substantial downward force is applied against the top of the outer cap.

Description

United States yatent [1 1 Wiiiis SAFETY CLOSURE ASSEMBLY [75] Inventor:

[73] Assignee: Aluminum Company of America, Pittsburgh, Pa.

[22] Filed: Aug. 31, 1972 [21] Appl. No.: 285,445

Primary Examiner-George T. Hall Attorney, Agent, or Firm-David W. Brownlee, Esq.

Wilburn C. Willis, Hagerstown, lnd.

[451 May 28, tam

[57] ABSTRACT A safety closure assembly is provided which includes an inner cap with threads formed in its skirt for affixation to a container by turning the cap, vertically aligned corrugations in the outer surface of the top portion of the cap skirt and an outwardly projecting bead on the lower edge of the skirt, and further including an outer flexible plastic cap which flts over the inner cap and which has inwardly projecting, vertically aligned teeth on its inner surface for engagement with the corrugations on the inner cap, an inwardly projecting flange on the bottom edge of the skirt for engagement under the bead 'on the inner cap to preclude separation of the caps, and an inwardly-upwardly inclined inner surface of the skirt above such flange for engagement against the outer surface of the bead on the inner cap to spring the outer cap upwardly with respect to the inner cap and thereby prevent engagement of the teeth on the outer cap with the corrugation on the inner cap unless substantial downward force is applied against the top of the outer cap.

6 Claims, 6 Drawing Figures PATENHEDumaum $812,990

SHEEI 2 BF 2 FIG. 5.

l SAFETY CLOSURE ASSEMBLY BACKGROUND OF THE INVENTION 1. Field of Invention This invention relates to a safety closure for a container of potentially poisonous materials for preventing a small child from unscrewing the closure from the container. It further relates to a safety closure assembly comprising an inner cap which is applied to, and removed from, a container by turning, and an outer flexible outer cap which prevents unscrewing of the inner cap by a small child.

2. Description of the PriorArt It is known to provide a two-piece closure assembly comprising an inner threaded cap adapted to be screwed on a container neck and an outer cap mounted on the inner cap with the inner and outer caps being capable of relative rotary and axial sliding movement and including interengageable lugs on the caps for clutching them together in one position of axial displacement of the two caps and including spring fingers integral with the inner cap for biasing the caps so that the lugs are disengaged. The spring fingers on such inner cap prevent engagement on the lugs on the two caps except when substantial pressure is applied against the top of the outer cap to overcome the spring pressure and thereby engage the lugs so that unscrewing the outer cap will also unscrew the inner cap. Such closure assembly is disclosed in US. Pat. No. 2,964,207. Other disclosures of interest are contained in US. Pat. Nos. 2.009.2l6, 2,359,639, 2,847,139, 2,980,274, 2,990,975 and 3,428,201.

The prior art does not disclose means for preventing a child from opening a conventional screw cap, or a safety closure assembly which includes'a conventional screw cap and an outer cap member which prevents a small child from unscrewing the conventional inner cap member.

SUMMARY OF THE INVENTION This invention provides a safety closure assembly comprising a conventional screw cap with vertical knurls in its skirt and an outwardly projecting curled bead on its bottom edge, and an outer flexible plastic cap over the inner cap, the outer cap having inwardly projecting vertically aligned teeth for engagement with the knurls on the inner cap. an inwardly projecting flange on the bottom ofthe cap skirt for preventingdisassembly of the caps, and an inwardly-upwardly inclined inner surface in the skirt above the flange for engagement against the outer surface of the bead on the inner cap to spring the outer cap upwardly and thereby prevent engagement of the teeth on such outer cap with the knurls on the inner cap except with the application of substantial downward force on the outer cap.

Accordingly, an object of the invention is to provide means for preventing a small child from unscrewing a conventional screw cap from a container.

Another object of the invention is to provide an outer flexible plastic cap having inwardly projecting teeth for engagement with knurls or corrugations on a conventional screw cap, an inwardly projecting flange for engagement under a bead on such screw cap, and an inwardly-upwardly inclined inner surface on the skirt of the outer cap for engagement against the outer surface of a bead on the inner cap to spring said outer cap upwardly.

Another object of the invention is to provide a safety closure assembly comprising an inner screw cap with corrugations in its skirt and a bead on the bottom of its skirt, and an outer flexible plastic cap over the inner cap having inwardly extending teeth for engagement with the corrugations in the inner cap and having an inwardly-upwardly inclined inner surface for engagement against the outer surface of the bead on the inner cap to spring the outer cap upwardly with respect to the inner cap to thereby prevent engagement of the teeth on the outer cap with the knurls on the inner cap ex cept with application of substantial pressure against the top of the outer cap.

BRIEF DESCRIPTION OF THE DRAWINGS FIG; 1 is'a side elevation view of an inner cap for a closure assembly of the invention;

FIG. 2-is atop plan view of the cap illustrated in FIG.

FIG. 3 is a partial cross-sectional view of an outercap for a closure assembly of the invention;

FIG. 4 is a top plan view of the outercap illustrated in FIG. 3;

FIG. 5 is a partial cross-sectional view ofa closure assembly of the invention secured on a bottle; and

FIG. 6 is a partial cross-sectional view similar to FIG. 5 illustrating engagement of the ribs on the outercap with knurls on the inner cap when pressure is applied against the top of the outercap.

DESCRIPTION OF A PREFERRED EMBODIMENT According to this invention, a safety closure assembly may comprise an inner cap member made of metal, preferably aluminumor an alloy thereof, and an outer cap made of plastic material. The inner cap may be of substantially conventional form including threads formed in the closure skirt, an outwardly projecting curled bead around the bottom edge of the closure skirt and vertical knurling in the closure skirt at or near its top. The outer plastic cap has inwardly projecting teeth in its skirt for engagement with the knurling on the inner cap, an inwardly projecting flange for engagement under the bead on the inner cap, and an inwardlyupwardly inclined surface in the closure skirt above such flange for engagement against the outer surface of the bead to spring the outer cap upwardly with respect to the inner cap. The spring action produced by the contact of the inwardly-upwardly inclined inside surface of the flexible skirt of the outer cap against the outer surface of the bead on the inner cap holds the outer cap in raised position on the inner cap so that the teeth on the outer cap do not engage the knurling on the inner cap. In such position, turning the outer cap will have no effect on the inner cap and will not unscrew the inner cap from the container on which it is secured. To remove the inner cap and the closure assembly from the container, the outer cap must be pressed down to overcome the spring action so that the teeth on the inside of the outer cap engage the knurling on the outside of the inner cap, and while so pressing,

3 the outer cap must be simultaneouslyturned in a counterclockwise direction so that the inner cap will be anscrewed from the container. lt has been found that this combination of simultaneous downward force and turning is not easily understood or effected by a small child. Consequently, a closure assembly which requires such simultaneous actions cannot be opened by most small children and provides a safeguard .against opening of a bottle which contains materials which are potentially poisonous.

Referring to FIGS. 1 and 2, an inner screw cap of substantially conventional configuration is illustrated comprising a top end wall 12 and a depending peripheral skirt 14 with threads 16 formed therein and a curled head 18 on the bottom edge of said skirt. Skirt 14 further includes vertically aligned corrugations or knurls 20 therein near its top. Knurls 20 may be formed by the method and apparatus disclosed in US. Pat. No. 3,623,442, or by other known methods and apparatuses. lf formed in accordance with US. Pat. No. 3,623,442, knurls 20 will project outwardly from the closure skirt. It will be apparent to those skilled in the art that other known methods of knurling can be used to form inwardly projecting knurls or ribs in the closure skirt. For example, this can be done by forming such knurls in the die in which the cap is formed as is well known in the art.

Bead 18 on cap 10 may be either inwardly or outwardly curled as illustrated and projects outwardly from the closure skirt around the circumference thereof. Bead 18 provides a relatively smooth outwardly projecting rounded surface on screw cap 10 for engagement against an inner surface of an outer cap thereover will be explained. lnner screw cap 10 may further include a liner 22 disposed therein against the undersurface of top end wall 12. Cap 10 is adapted to be secured on a threaded bottle mouth opening by turning the cap so that threads 16 therein engage matching threads on the container mouth to draw the cap against the container mouth compressing liner 22 against a top sealing surface on the container mouth to form a seal therebetween.

FIGS. 3 and 4 illustrate a flexible plastic outer cap 24 which is adapted to be assembled over inner cap 10. Outer cap 24 includes a top end wall 26 and a depending peripheral skirt 28 around the top end wall. Skirt 28 has an inwardly projecting flange 30 around its periphery, an inwardly-upwardly inclined inner surface 32 above flange 30, and a plurality of inwardly projecting, vertically aligned teeth 34 near the top of the closure skirt for engagement with knurls or corrugations on the exterior surface of the inner cap 10. Outer cap 24 may further include a plurality of small serrations in its outer surface so that the cap can be more easily gripped for turning a closure assembly for application to, or removal from a container.

lnwardly-upwardly inclined surface 32 on the skirt of plastic over cap 24 is preferably angled approximately 5 to and preferably about 10, from vertical so that it will engage the upwardly-outwardly facing surface of bead 18 on inner closure 10 when the two caps are assembled as illustrated in FIGS. 5 and 6. Any pressure between surface 32 and bead 18 will therefore produce both vertical and horizontal reactions of cap skirt 24 as will be explained later.

The inner edges of teeth 34 are also preferably inclined inwardly from top to bottom to accommodate variations in dimensions of the inner and outer caps. It

is believed that such inwardly-upwardly incline of the inner edges of teeth 34 may also help to prevent engagement of the teeth with the corrugations in the inner cap 10 unless substantial top pressure is applied against the outer cap.

FIG. 5 illustrates a safety closure assembly 38 comprising inner screw cap 10 and outer cap 24 sealed on a bottle entrance mouth 40. Entrance 40 includes an upwardly facing sealing surface 42 and an outwardly facing surface 44 with threads 46 or other closure retaining means thereon, and an outwardly projecting circumferential bead 48 below such threads for handling or transferring the container. In the sealed condition of container 40, threads 16 on screw cap 10 are in engagement with threads 46 on the container and liner 22 in the cap is in a compressed condition against the top sealing surface 42 of hte container. Flange 30 on outer cap 24 is disposed below bead 18 on inner screw cap 10 so that the outer cap cannot be lifted from the inner screw cap, and inclined surface 32 on the outer cap is in engagement against the outer surface of bead 18 to hold the outer cap in a raised position on screw cap 10. In such raised position, the teeth 34 on the outer cap 24 are not engaged with corrugations 20 on inner screw cap 10, and rotation or unscrewing of the outer cap has no effect on the inner cap. As stated above, it is believed that the inwardly-upwardly incline of teeth 34 on outer cap 24 may also assist in holding the outer cap in such raised position on the inner cap.

To remove closure assembly 38, outer cap 24 must be pressed downwardly against inner cap 10 to engage teeth 34 in corrugations 20 so that unscrewing of the outer cap will also unscrew the inner cap from container entrance mouth 40. Pressure applied against the top of outer cap 24 forces the flexible skirt 28 of the outer cap outwardly as inclined surface 32 in the skirt slides downward with respect to bead 18 on the inner cap to permit relative vertical displacement of the outer cap on the inner cap and engagement of teeth 34 and corrugations 20. An angle of approximately 10 from vertical for surface 32 has been found to provide sufficient spring effect of cap skirt 28 to prevent a child from opening closure assembly 38, but permit an adult to press the outer cap down for unscrewing the assem bly from a bottle. A l0 angle also provides a sufficiently vertical incline on surface 32 to insure contact thereof against bead 18 on inner cap 10 with normal tolerances for the caps.

To reseal container 40 with closure assembly 38, the closure assembly is positioned on a container mouth entrance 40 and turned or screwed in a clockwise direction to engage threads 16 on inner cap 10 with threads 46 on the container mouth. It will be necessary to apply some downward pressure on outer cap 24 during such turning so that inner cap 10 will also be turned. When inner cap 10 has been rotated to the position of full engagement of the threads, further rotation of the outer cap will disengage teeth 34 from corrugations 20. Teeth 34 and corrugations 20 must then be reengaged by the application of top force against outer cap 24 before the inner cap and assembly can be removed from the container by counterclockwise turning of the outer cap.

It is therefore seen that a safety closure assembly has been illustrated and described which includes a substantially conventional metal screw cap with a flexible plastic outer cap over the screw cap to prevent unscrewing of the screw cap from a container without the application of substantial top pressure against the outer cap. Although a preferred embodiment of the invention has been illustrated and described, it will be apparent to those skilled in the art that numerous variations can be made in the assembly without departing from the invention. For example, the corrugations on the inner cap may be provided cutting vertical slits or lances in the cap skirt and deforming the alternating metal sections between such slits either inwardly or outwardly in the skirt. The edges of every other metal section can thereby be exposed for engagement with teeth on an outer cap which may be telescoped over such an inner cap. The inner cap may also be molded from plastic material and have molded corrugations or ribs thereon.

What is claimed is:

l. A safety closure assembly for containers of potentially poisonous materials to prevent opening by a small child comprising an inner cap adapted to be turned to apply it to, and remove it from, a container mouth and having substantially vertically aligned corrugations in the outer surface of the top portion of its skirt and an outwardly projecting annular bulge around the inner cap near the bottom edge ofits skirt, and an outer flexible plastic cap over said inner cap, said outer cap having inwardly projecting, substantially vertically aligned teeth therein for engagement with said corrugations on the inner cap, and the skirt of said outer cap having an inwardly projecting flange thereon for engagement under said bulge on the inner cap to preclude separation of said caps, and an inwardly-upwardly inclined inner surface above said flange for engagement against the outer surface of said bulge to spring said outer cap upwardly with respect to said inner cap and thereby prevent engagement of said teeth with said corrugations unless substantial downward force is applied against the top of the outer cap.

2. A closure assembly as set forth in claim 1 in which said inwardly-upwardly inclined surface is disposed an angle of approximately 10 from vertical.

3. A closure assembly as set forth in claim 1 in which the inner edges of each of said teeth is angled inwardly from the bottom to the top of the teeth.

4. A closure assembly as set forth in claim 1 in which said bulge is a bead on the bottom edge of the closure skirt.

5. A closure assembly as set forth in claim 1 in which said corrugations in said inner cap include substantially vertically aligned ribs which project either inwardly or outwardly from said inner cap skirt.

6. A closure assembly as set forth in claim 1 in which said bead on said inner cap is outwardly curled.

Claims

1. A safety closure assembly for containers of potentially poisonous materials to prevent opening by a small child comprising an inner cap adapted to be turned to apply it to, and remove it from, a container mouth and having sUbstantially vertically aligned corrugations in the outer surface of the top portion of its skirt and an outwardly projecting annular bulge around the inner cap near the bottom edge of its skirt, and an outer flexible plastic cap over said inner cap, said outer cap having inwardly projecting, substantially vertically aligned teeth therein for engagement with said corrugations on the inner cap, and the skirt of said outer cap having an inwardly projecting flange thereon for engagement under said bulge on the inner cap to preclude separation of said caps, and an inwardlyupwardly inclined inner surface above said flange for engagement against the outer surface of said bulge to spring said outer cap upwardly with respect to said inner cap and thereby prevent engagement of said teeth with said corrugations unless substantial downward force is applied against the top of the outer cap.

2. A closure assembly as set forth in claim 1 in which said inwardly-upwardly inclined surface is disposed an angle of approximately 10* from vertical.