Spray cap for container

Abstract

A spray cap for a spray container constitutes a one-piece moulding of polymeric material and includes a cap plate in which a plurality of spray slits is formed. Integral with the cap plate is a non-return valve arranged to permit air to flow through it in one direction which, in use, is towards the interior of the spray container but substantially to prevent flow of air through it in the opposite direction.

Claims

1. A spray container including an open-topped receptacle with a flexible, resilient wall and a spray cap connected to the top of the receptacle, the spray cap comprising a one-piece moulding of polymeric material and including a cap plate, a plurality of spray slits formed in said cap plate and a non-return valve which is integral with said cap plate and is arranged to permit air to flow through said non-return valve in one direction which, in use, is towards the interior of said spray container but substantially to prevent the flow of air through it in the opposite direction, wherein the width of each of the spray slits varies along its length between substantially 0 and 0.3 mm.

2. The spray container and the spray cap as claimed in claim 1 wherein each of the spray slits is defined by two edges of irregular shape which substantially contact one another, at least in certain regions.

3. The spray container and the spray cap as claimed in claim 2 wherein the width of each of the spray slits varies along its length between substantially 0 and 0.1 mm.

4. The spray container and the spray cap as claimed in claim 3 wherein the width of each of the spray slits varies along its length between substantially 0 and 0.05 mm.

5. The spray container and the spray cap as claimed in claim 1 wherein the spray slits are arranged in a substantially circular array.

6. The spray container and the spray cap as claimed in claim 1 wherein the cap plate is substantially circular and the spray slits extend substantially radially.

7. The spray container and the spray cap as claimed in claim 6 wherein the cap plate includes an annular region which is inclined upwardly and inwardly and in which the spray slits are formed.

8. The spray container and the spray cap as claimed in claim 1 wherein the non-return valve is of generally duckbill type including two valve plates which are inclined towards one another and are integral with the cap plate and whose ends remote from the cap plate are biased towards one another and are separated by a slit.

9. The spray container and the spray cap as claimed in claim 1 further including inner and outer regions of different plastic materials, the spray slits formed in the inner region and the non-return valve forming part of the inner region.

10. The spray container and the spray cap as claimed in claim 9 wherein the plastic material of the inner region is softer and more resilient than the plastic material of the outer region.

11. The spray container and the spray cap as claimed in claim 1 further including a closure cap moulded integrally with the cap plate and connected to it by an integral hinge, whereby the closure cap is movable between a closed position in which it covers the cap plate and an open position in which it does not.

12. The spray container and the spray cap as claimed in claim 11 wherein the cap plate has a recess formed in its upper surface and the closure cap has a projection formed in its underside which is received in the recess in the cap plate when the closure cap is in the closed position.

13. The spray container and the spray cap as claimed in claim 12 wherein the outer surface of the projection and the inner surface of the recess carry a recess and a projection which cooperate to form a snap connection when the closure cap is in the closed position.

14. The spray container and the spray cap as claimed in claim 11 wherein the closure cap includes a region on its underside which is shaped and positioned so that it comes into contact with the region of the cap plate in which the spray slits are formed, when the closure cap is in the closed position, whereby the spray slits are closed.

15. The spray container and the spray cap as claimed in claim 3 wherein the width of each of the spray slits varies along its length between substantially 0 and 0.01 mm.

16. A spray cap for a spray container, the spray cap comprising: a cap plate; a cylindrical wall depending from the cap plate; a recess formed in the cap plate; an upwardly and inwardly inclined annular region formed in the cap plate about the recess; a plurality of spray slits formed in the inwardly inclined annular region of the cap plate; and a non-return valve extending from the recess, the non-return valve arranged to permit air to flow through said non-return valve in one direction which, in use, is towards an interior of the spray container but substantially to prevent the flow of air through it in the opposite direction; wherein the spray cap is a one-piece moulding of polymeric material.

17. The spray cap as claimed in claim 16 further including inner and outer regions of different plastic materials, the spray slits formed in the inner region and the non-return valve forming part of the inner region, wherein the plastic material of the inner region is softer and more resilient than the plastic material of the outer region.

18. The spray cap as claimed in claim 16 further including a closure cap moulded integrally with the cap plate and connected to it by an integral hinge, wherein the closure cap includes a projection formed on an underside thereof that is received in the recess formed in the cap plate in a snap connection when the closure cap is in a closed position.

19. The spray cap as claimed in claim 16 further including a closure cap moulded integrally with the cap plate and connected to it by an integral hinge, wherein the closure cap includes a region on its underside which is shaped and positioned so that it comes into contact with the upwardly and inwardly inclined annular region formed in the cap plate, when the closure cap is in the closed position, to thereby close the spray slits.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and details of the invention will be apparent from the following description of one specific embodiment, which is given by way of example only with reference to the accompanying drawings, in which:

(2) FIG. 1 is a perspective view from above of a spray cap in accordance with the invention with the lid in the open position;

(3) FIG. 2 is an axial sectional view of the spray cap of FIG. 1 with the lid in the closed position;

(4) FIG. 3 is a perspective view from below of the central portion only of the spray cap of FIG. 1; and

(5) FIG. 4 is an axial sectional view of the upper portion of a spray container including the spray cap of FIG. 1.

DETAILED DESCRIPTION

(6) The spray cap shown in the drawings is a one-piece injection moulding and consists of an outer cylindrical wall 2, whose lower end is open and whose upper end is closed by an integral circular cap plate 4. Integrally connected to the upper end of the wall 2 by means an integral hinge 6 is a pivotable cap 8. The central circular portion 10 of the cap plate is made of a relatively soft resilient thermoplastic material, e.g. a thermoplastic elastomer such as SEBS. The remainder of the cap plate and also the cylindrical wall and the cap is made of a somewhat harder and more rigid material, such as polypropylene random copolymer. The upper surface of the central portion 10 is not flat and instead includes a coaxial annular outer portion 12 whose upper surface is inclined upwardly and inwardly. Formed in this portion 12 is a plurality of relatively short spray slits 14, e.g. numbering 22 in all, though the number may be varied at will, which extend generally radially and are directed axially and outwardly. Formed in the centre of the central portion 10 is a recess 16, the shape of whose upper portion is circular. The circular wall 18 defining the circular portion of the recess merges into two downwardly extending valve plates 20, which together constitute what is effectively a duckbill valve. The lower ends of the plates 20 closely approach one another and are separated only by a narrow slit 22. The duckbill valve 20, 22 constitutes a non-return valve arranged to permit air to flow into the liquid receptacle, when the spray cap is attached to such a receptacle, when the pressure within the receptacle is sub-atmospheric but substantially to prevent the flow of air and liquid out of the receptacle towards the exterior.

(7) The cap 8 carries a central protuberance or spigot 24, whose size, shape and position correspond to those of the recess 16. The cap 8 also carries an annular protuberance 26, a portion 28 of whose annular surface is inclined downwardly and outwardly, when the cap is in the closed position. The shape and position of the surface 28 correspond to those of the surface 12 of the central portion of the cap plate. The cap is pivotable about its hinge 6 between the open position shown in FIG. 1 and the closed position shown in FIG. 2 in which the surface 28 engages the surface 12 and thus seals the spray slits 14.

(8) FIG. 4 shows the spray cap attached to the cylindrical neck 30 of a receptacle for a liquid to be dispensed, such as a toilet cleaner. The spray cap may be attached to the receptacle in any desired manner but in the present case the neck 30 has an annular projecting bead 34 on its outer surface. The cylindrical wall 2 of the spray cap has a corresponding, inwardly projecting bead 36 on its inner surface. The beads 34 and 36 are so dimensioned and positioned that the spray cap may be pushed downwardly onto the neck of the receptacle with the cylindrical wall 2 surrounding the neck 30. When the bead 36 on the cylindrical wall 2 impinges against the bead 34 on the neck 30, the cylindrical wall 2 is expanded outwardly, thereby permitting the bead 36 to slide over the bead 34. When the bead 36 has passed over the bead 34, the cylindrical wall will return to its original shape with the bead 36 locked beneath the bead 34 and the upper surface of the neck 30 drawn into sealing engagement with the underside of the cap plate 4.

(9) When the spray cap is to be manufactured, an injection mould is used which defines, when the mould is closed, a volume corresponding to the shape of the spray cap and lid in the configuration shown in FIG. 1. A barrier is initially positioned in the mould cavity which divides that portion which will form the central portion of the cap plate from the remainder of the cavity. A relatively soft and resilient thermoplastic material is then injected into that portion of the mould cavity which will define the central portion of the cap plate. Once this thermoplastic material has set, the barrier is removed and a somewhat harder and more rigid plastic material is then injected to fill the remainder of the mould cavity. The two portions of plastic material are therefore integrally connected together. The mould member defining the underside of the cap plate carries a number of projections, each of which has an elongate, radially extending apex, which, when the mould is closed, is spaced by only between 0.0075 and 0.075 mm from the opposing surface of the other mould member, whereby a plurality of narrow elongate gaps are defined. When the relatively soft, resilient thermoplastic is injected into the central portion of the mould cavity, the presence of these narrow gaps will result in the formation of the spray slits, as described in detail in EP2736695A. That mould member which defines the upper surface of the cap plate carries a further and very much larger projection, whose purpose is to define the internal surface of the circular wall 18 and the valve plates 20. This larger projection also has an elongate apex and when the mould is closed this apex will also be spaced from the opposed surface of the other mould member by a distance of only between 0.0075 and 0.075 mm, whereby when the thermoplastic material is injected the slit 22 is formed, as discussed in detail in EP2736695A. Both the slit 22 and also the spray slits 14 are of negligible width and, as described above, will be defined on a microscopic scale by two somewhat irregular edges whose spacing will vary along the length of the slits between substantially zero and 0.05 mm, more preferably 0.01 mm.

(10) If it is desired to dispense liquid from the receptacle, the receptacle is inverted and pressure is applied to its flexible resilient wall 32, thereby increasing the pressure of its contents. This pressure will have the effect of making the slit 22 in the non-return valve even narrower because the pressure will act on the external surfaces of the walls 20 and push them even closer together. The pressure will have no effect on the width of the spray slits 14 and liquid will therefore pass through these narrow slits and be broken up by them, particularly as a result of their somewhat irregular shape, into a fine spray. A number of sprays equal to the number of spray slits will therefore emanate from the spray cap and as a result of the inclination of the inclined portion 12 in which the spray slits 14 are formed, these sprays will move in an axial and outward direction, thereby producing a relatively large area of coverage. Due to the fact that the non-return valve 20, 22 is substantially closed, substantially no liquid will pass through it. If a further spray is required, the receptacle is again inverted and the pressure on its side wall released. This will result in the creation of a sub-atmospheric pressure in the receptacle due to the resilience of the side wall and the action of this pressure on the outer surface of the valve plates 20 results in the slit 22 opening somewhat and thus affording a relatively large area through which air may be drawn by the sub-atmospheric pressure at a significant rate. Air will also be drawn in through the spray slits 14 but only to a very minor extent because the width of the spray slits is not influenced by the existence of a sub-atmospheric, or indeed super-atmospheric, pressure beneath them. The container therefore returns rapidly to its original shape and the spraying process may be repeated as many times as is desired. When spraying is complete, the cap 8 is pivoted about its integral hinge into the closed position shown in FIG. 2 in which the surface 28 on the cap closely abuts the surface 12 on the cap plate and thus closes the spray slits 14 and the spigot 24 is received as a sliding fit in the recess 16 in the cap plate. If desired, the external surface of the spigot 24 and the internal surface of the cylindrical wall 18 may be provided with cooperating beads which will effect a snap connection to hold the cap 8 locked in the closed position.