GB2046227A

GB2046227A - Cap for a container and method of and mould for making the cap

Info

Publication number: GB2046227A
Application number: GB8009920A
Authority: GB
Original assignee: PAC PLAS Ltd
Current assignee: PAC PLAS Ltd
Priority date: 1979-03-24
Filing date: 1980-03-24
Publication date: 1980-11-12

Abstract

Caps for aerosol containers are normally fitted between the rim and domed top thereof. An aerosol cap 10 is in the form of a cylinder, open at one end, with an external flange 12 adjacent to, but spaced from the open end whereby, in use, the rim of the container is covered by the flange. Also disclosed are a mould and moulding method suitable for use in producing an article such as the cap by injection moulding, the mould being diameterized by article stripping means (261, Figs. 3-5 (not shown). <IMAGE>

Description

SPECIFICATION Cap for a container and method of and mould for making the cap This invention relates to a cap for a container and more particularly a cap for a pressurised container of the kind commonly called an "aerosol" container. The provision of a cap protects the release valve in the top of the aerosol container and also enables the containers to be stacked on top of one another.

The invention also relates to a mould and a method of making articles (for example the cap) in the mould.

It is known to provide caps for aerosol containers.

A common type of cap has the form of a hollow cylinder, the opend end of which is adapted to engage between the upper rim of the aerosol container and the domed top in which the valve for release of the contents is located. With this type of cap the rim of the aerosol is exposed which is disadvantageous in that stacking is impaired.

According to the present invention, there is provided a cap for a container comprising a hollow cylinder which is open at one end only, an outwardly directed flange extending around the exterior of the cap adjacent the open end, the flange being positioned such that it covers the top of the rim of a container when the cap is located on the container with the open end inside the container rim.

The invention also provides a mould for making an article such as a cap for a container by injection moulding comprising in association to define a mould cavity; a first female mould part; a seond female mould part; a male mould part projecting from the one female mould part; and a member within the male mould part, the female mould parts being separable, the male mould part being movable relative to the one female mould part to project further therefrom, and the member within the male mould part being movable to shed an article moulded in the cavity and embracing the male mould part.

Preferably the first female mould part is fixed and the second female mould part is movable towards and away from it. The second female mould part is preferably formed to define with the first female mould part an outer rim on an article. The male mould part can be recessed to provide an internal rim on an article.

The invention also provides a method of moulding an article including a wall having adjacent a free end thereof one or more outer projections and one or more inner projections, comprising; providing a mould as aforesaid, wherein the or each outer projection is formed by a portion of the mould cavity at the part line between the first and second female mould parts and the or each inner projection is formed by a part of the mould cavity defined by the male mould part and within the first female mould part; injecting material into the mould to fill the cavity and set to form the article; separating the second female mould part from the remaining mould parts; moving the male mould part relative to the first female mould part to dispose the free end of the wall clear of the first female mould part; and moving the member within the male mould part to engage the article and shed it from the male mould part, by causing the wall to spring and expand as the or each inner projection is drawn from that part of the cavity defined by the male mould part and originally surrounded by the first female mould part.

Although the male mould part has been said to be movable relative to the first female mould part (which is normally stationary), such movement, it will be understood, is relative and the first female mould part could move if so desired.

The article can be a cap, in which case the cavity would define a wall having the shape of a right cylinder, and a closure disc for one end thereof, the other having the aforesaid projections.

The invention will now be described further by way of example, with reference to the accompanying drawings, in which:~ Figure 1 is a side elevation of a cap; Figure 2 is a fragmentary cross-sectional view of part of a mould of the invention in a first disposition thereof; Figure 4 is a similar view with the mould in a second disposition; and Figure 5 is another similar view but with the mould in a third disposition, Referring to Figs. 1 and 2 the cap comprises a hollow cylinder 10 preferably of plastics which is open at one end. An outwardly directed flange 12 extends around the exterior of the cap adjacent the open end. As can be seen in the drawing the lower surface 14 of the flange 12 is flat whereas the upper surface 16 is convex.

The interior of the cap is conventional in that it is provided with an inwardly directed lip 18 formed with a succession of flats 20, each in the form of a short, chordal movably extending rib.

In use the cap is fitted on a container with the open end located inside the rim, the flats 20 on the lip 18 engaging the domed container top. The flange 12 extends across the top of the container rim. Preferably, when the cap is in position on the container the clearance between the bottom 14 of the flange and the top of the rim is a minimum. The spacing of the flange from the open end of the cap is selected to achieve that.

A preferred mould 22 and moulding method of the invention are illustrated in Figs.

3 to 5. Referring firstly to Fig. 3, mould 22 has a first fixed female mould part 23, a second, movable, female mould part 24, a male mould part 25, a member or poppet 26 within the male mould part 25 and a moulding material supply channel 27. Fig. 3 shows the mould closed and having been filled with material to produce a cap 10 as described above. A portion of the mould cavity for producing outer flange 12 is defined by the front face of part 23 and a chamfer 28 on part 24. A portion of the mould cavity for producing the inwardly directed lip 18 and flats 20 is formed by an annular depression 29 in the male mould part 25.

When the moulding material has set and the cap 10 producing the article is removed by firstly separating female mould part 23 by moving it in the direction of arrow 30 (Fig. 4).

Next (or simultaneously) the male mould part 25 and poppet 26 are moved in the direction of arrow 31 a distance 'd' to move the projection 18 clear of female mould part 23 (also Fig. 4). Finally poppet 26 is moved to the left to shed the cap from the male mould part 25 (Fig. 5), the lip 18 being sprung as it is drawn from the annular depression 29.

Claims

1. A cap for a container comprising a hollow cylinder which is'open at one end only, an outwardly directed flange extending around the exterior of the cylinder adjacent to, but spaced from, the open end, the flange being positioned such that it covers the top of the rim of a container when the cap is located on the container with the open end inside the container rim.

2. A cap as claimed in Claim 1, wherein the surface of the flange remote from the open end of the cylinder is convex.

3. A cap as claimed in Claim 1, or Claim 2, wherein the surface of the flange nearest to the open end of the container is flat.

4. A cap as claimed in Claim 3, wherein the surface of the flange nearest to the open end of the container lies in a plane perpendicular to the axis of the cylinder.

5. A cap as claimed in any preceding claim, wherein an inwardly directed lip is provided around the inside of the cylinder.

6. A cap as claimed in Claim 5, wherein the lip is provided with a plurality of flat portions.

7. A cap for a container substantially as described herein with reference to the accompanying drawing.

8. A mould for making an article such as a cap for a container by injection moulding comprising, in association to define a mould cavity; a first female mould part; a second female mould part; a male mould part projecting from the one female mould part; and a member within the male mould part, the male mould part being movable relative to the one female mould part to project further therefrom, and the member within the male mould part being movable to shed an article moulded in the cavity and embracing the male mould part.

9. A mould as claimed in Claim 8, wherein a first female mould part is fixed and the second female mould part and the male mould part are movable relative thereto.

10. A mould as claimed in Claim 8 or 9 wherein the second female mould part in shaped to define with the first female mould part a portion of the mould cavity at their mutual part line capable of forming an outer projection on the article.

11. A mould substantially as hereinbefore described with reference to and as illustrated in Figs. 3, 4 and 5 of the accompanying drawings.

12. A method of moulding an article including a wall having adjacent a free end thereof one or more outer projections and one or more inner projections, comprising: providing a mould as claimed in any of claims 8 to 11, wherein the or each outer projection is formed by a portion of the mould cavity at the part line between the first and second female mould parts and the or each inner projection is formed by a part of the mould cavity defined by the male mould part and within the first female mould part; injecting material into the mould to fill the cavity and set to form the article; separating the second female mould part from the remaining mould parts; moving the male mould part relative to the first female mould part to dispose the free end of the wall clear of the first female mould part; and moving the member within the male mould part to engage the article and shed it from the male mould part by causing the wall to spring and expand as the or each inner projection is drawn from that part of the mould cavity defined by the male mould part and originally surrounded by the first female mould part.

13. A method of moulding an article substantially as hereinbefore described with reference to and as illustrated in Figs. 3 to 5 of the accompanying drawings.