TECHNICAL FIELD

The present disclosure relates to dispensers for expelling fluids from a container and more particularly to a dispenser for expelling cleaning, sterilising or skin care products, including products such as soaps, gels, disinfectants, moisturizers and the like. The disclosure is specifically directed to pumps having springs that are axially compressible and that cause dispensing by an axial reduction in volume of a pump chamber.

BACKGROUND

Fluid dispensers of various types are known. In particular, for dispensing of cleaning products such as soaps, there are a wide variety of manually or automatically actuated pumps that dispense a given quantity of the product into a user's hand.

Consumer products may comprise a dispensing outlet as part of the package, actuated by a user pressing down the top of the package. Such packages use a dip tube extending below the level of the liquid and a pump to aspirate the liquid and dispense it through an outlet spout. These packages will be referred to in the following as top- actuated dispensers. In a conventional manner, such fluid dispensers include a body and dispenser means that are moved manually by the user with respect to the body between a rest position and a dispensing position, allowing to dispense the fluid through the outlet spout. Usually the pump is a piston pump and a resilient member, such as a spring, is generally used to urge the dispenser means towards its rest position, so that the user must exert a force in order to achieve the movement towards the dispensing position, and when the user removes the force, the resilient member automatically returns the dispenser means into its rest position. Generally, spiral springs made of metal are used as return springs. This may present a certain number of drawbacks.

Firstly, the metal may interact with the fluid, in particular with aqueous or alcohol based fluids, and this may have a harmful effect on the dispensing fluid.

Disposable fluid dispensers are usually made of a plastics material and using a metal spring decreases the recyclability of such fluid dispensers.

In addition, the conventional pumps use ball valves as inlet and outlet valves to the pump chamber. These may be gravity operated or spring-biased. Assembly of such ball valves adds to the manufacturing complexity, in particular due to the increased number of individual components that need to be assembled.

It would be desirable to provide a dispenser that could alleviate at least some of the drawbacks of the known dispensers.

SUMMARY

In view of the fluid dispensers of the above-mentioned types, it is desired to provide an alternative dispenser. The dispenser may be disposable and is desirably reliable when used, yet simple, hygienic and economical to produce.

The invention relates in particular to a pump assembly according to appended claim 1 , a fluid dispenser according to appended claims 16 and 19 and the use of a plastomer spring-valve combination according to appended claim 20. Embodiments are set forth in the appended dependent claims, in the following description and in the drawings.

Thus, there is provided a pump assembly comprising: a pump cylinder defining an axis and having a lower end with a pump inlet for taking in the fluid and an upper end; a feed conduit having a first and second conduit end, wherein the first conduit end is connected to the pump inlet and the second conduit end, in use, opens out below a fluid level; and an actuator comprising a piston portion slideably engaged within the pump cylinder and a dispenser portion extending out from the upper end of the pump cylinder, the actuator having a pump outlet channel extending therethrough from a pump outlet at the piston portion to a dispensing outlet in the dispenser portion;

wherein a spring is provided within the pump cylinder, the spring comprising at least one spring section, a first end portion engaged against the lower end of the pump cylinder and a second end portion engaged with the piston portion, which spring section can be compressed in the axial direction from an initial condition to a compressed condition and can subsequently expand to its initial condition to bias the actuator upwards, and wherein a first valve element is provided at the first end portion of the spring, and a second valve element is provided at the second end portion of the spring, the spring section and at least one of the first and second valve elements being integrally formed of plastomer material to form a spring valve combination, and wherein the first and second valve elements define respective one-way inlet and outlet valves for the pump assembly. The use of such a spring valve combination for a fluid pump allows use of an axial force to dispense fluid from a fluid reservoir. The fluid may be soap, detergent, disinfectant, moisturizer or any other form of cleaning, sterilising or skin care product. It may also vary widely in viscosity and composition. The integral forming of the spring and the valve elements at the end portions of the spring has the advantage that the spring and the valve elements can act in conjunction when an axial force is exerted on the spring. Under influence of an axial force, the spring may be compressed and then acts as an energy reservoir. With the axial movement of the spring and the compression thereof, the first and second end portions with the respective valve elements will move with respect to each other, in this case towards each other. This causes a volume reduction in the pump chamber formed between the pump cylinder and the piston portion. Under the thereby created overpressure, the second valve element will open and fluid will be expelled through the pump outlet to the dispensing outlet. When the axial force is released, the energy of the spring is released and the end portions with their respective valve elements will move away from each other. The volume of the pump chamber will increase and because of the expelled fluid, an underpressure is created. This causes the first valve to open and fluid will be sucked into the pump chamber via the feed conduit.

Integrally forming the spring valve combination allows a fluid pump with such a combination to be built of less parts, for example with only three components, namely the spring valve combination, the pump cylinder and the actuator. The use of less parts may be advantageous in terms of manufacture and assembly and also for recycling purposes. Furthermore, each of the components may be non-metal or plastic, further improving recycling.

In one embodiment, the first valve element is formed as a circumferential element projecting outwardly from the first end portion, for instance as a circumferential skirt extending towards the second end portion. Alternatively, the first and/or second valve elements may each be formed as a circumferential disk, projecting outwardly from the respective end portion of the spring. In one embodiment, the disk is flat, i.e. planar. In another embodiment, the first and/or second valve element may be conical or frusto- conical.

The first valve element may have an outer diameter that extends beyond the width of the spring sections to engage an inner surface of the pump cylinder to form the inlet valve. Additionally, the skirt or disk may be part spherical or of a parabola shape. The second valve element may surround the second end portion and may have a similar shape and size to the first valve element e.g. extending outwards and away from the first end portion and bearing against the inner surface of the pump cylinder.

In another embodiment, the second valve element may have a relatively smaller diameter than the first valve element. The pump outlet may comprise a bore for engagement of the second end portion and the bore may have a smaller inner diameter than an outer diameter of the second valve element such that the second valve element is compressed in a radial direction within the bore and an interior of the bore adjacent the second valve element forms a second valve seat.

In a still further embodiment, the first valve element may be a spring biased ball valve, retained within a valve chamber formed in the first end portion. The spring biased ball valve may be integrally formed in situ within the first end portion or it may be inserted during manufacture. In this context, reference to a ball valve is not intended to be limiting on the shape of the valve, which may be spherical, hemi- spherical, bullet- shaped or any other suitable shape that can interact with an appropriate mating valve seat of the valve chamber or formed in the pump cylinder.

The disclosure further provides for an integrally formed valve comprising a captive valve element as described above or further described hereunder. The integrally formed valve may comprise a valve support element and a lid, integrally connected together by a living hinge and together forming a valve chamber, the lid comprising an inlet opening to the valve chamber. The valve further comprises a valve element having a biasing spring, integrally formed together with the valve support element, the biasing spring acting to bias the valve element against a valve seat formed around the inlet opening. In an embodiment, the lid may be omitted and the valve element may close against a valve seat formed at the pump inlet.

The construction of the pump cylinder and the piston portion may be largely conventional. In one embodiment, the pump cylinder comprises an inwardly extending retention element adjacent its upper end for preventing retraction of the piston portion from the pump cylinder. The retention element may be a ridge, either continuous or interrupted, a barb or any other protrusion on the surface of the cylinder. It may also be provided on a separate member, such as a ring engaged within the upper portion of the cylinder or be part of a closure over the upper end of the pump cylinder. Alternative embodiments will be understood to be possible, according to the manufacturing technique chosen. The pump cylinder may even be made from multiple elements, adhered, welded or otherwise joined together whereby the piston portion is retained within the pump cylinder.

The piston portion may also comprise a seal, slideably engaged against an inner surface of the pump cylinder. The seal may be any appropriate seal such as an O-ring, or an integral seal such as a lip formed on the piston portion.

According to a further embodiment, the first end portion and/or the second end portion of the spring body may comprise an engaging member for engaging the spring valve combination within the pump chamber. The first and second end portions may be formed to interact with other components of the pump to maintain the spring in position. In one embodiment, they may form cylindrical or part-cylindrical or frusto- conical plugs that may interact with the pump inlet and the pump outlet, respectively. The shape of the respective engaging member will depend upon the shape of the respective portion of the pump inlet or pump outlet. The engaging members and the respective mating portions may be manufactured to have complementary engaging shapes such as ridges and grooves or the like or may merely be an abutment, allowing transmission of the necessary forces between the spring and the pump inlet and outlet.

According to an embodiment, the first and second end portions each comprise at least one flow passage for allowing fluid through or around the respective portion. The first and second end portions may also be formed with passages or channels to allow fluid to flow along the spring past or through these respective end portions. The passages in the first end portion allow fluid to flow into the pump chamber via the first valve element upon exerting an axial compressing force on the spring body. The passages in the second end portion allow fluid to flow past an engaging member at the second end portion and, during compression of the spring section, past the second valve element. In a particular embodiment, at least one flow passage at the second and/or first end portion is provided on or in the engaging member.

The spring section may have any appropriate form. In particular embodiments, the spring section may have an open shape that is mouldable or injection mouldable. In particular, the spring section may be helical, concertina- like (zigzag shape, S-shape, etc.), leaf-spring like or otherwise and may have an outer envelope corresponding to the interior of the pump chamber. The spring may also comprise a series of axially-aligned, spring sections, each of which can be compressed in the axial direction from an initial open condition to a compressed condition and is biased to subsequently expand to its open condition. The spring sections may have any appropriate shape in their initial open condition, including circular, ellipse, rhombus or the like. They may also be rotationally symmetrical around the axis such as a circular concertina or two- dimensional, having a generally constant shape in one direction normal to the axis such as a leaf-spring. In a particular embodiment, the spring body comprises two- dimensional or leaf spring sections. These have the advantage that they may be relatively easily moulded in a two part mould. They may also be less susceptible to twisting or distortion than helical springs.

According to a particular embodiment, the spring comprises a plurality of open spring sections that connect the first end portion to the second end portion. In a more particular embodiment, the spring comprises a plurality of rhombus shaped spring sections, joined together in series at adjacent corners. In the present context, reference to "rhombus shaped" is not intended to limit the invention to spring sections of the precise geometrical shape having flat sides and sharp corners. The skilled person will understand that the shape is intended to denote a mouldable form, such as an injection mouldable form that will allow resilient collapse, while using the material properties of the plastomer to generate a restoring force. Furthermore, since the resiliency of the structure is at least partially provided by the material at the corner regions, these may be at least partially reinforced, curved, radiused or the like in order to optimise the required spring characteristic.

In a particular embodiment, each spring section comprises four flat leaves joined together along hinge lines that are parallel to each other and perpendicular to the axial direction. In this context, flat is intended to denote planar. The resulting configuration may also be described as concertina like. The flat leaves may be of constant thickness over their area. The thickness may be between 0.5 mm and 1.5 mm, depending on the material used for the pump and the geometrical design of the pump and the spring. For example, a thickness between 0.7 and 1.2 mm has been found to offer excellent collapse characteristics in the case of leaves having a length between hinge lines of around 7 mm. In other words, the ratio of the thickness of the leaf to its length may be around 1 : 10, but may range from a ratio of 1 :5 to a ratio of 1 : 15. The skilled person will recognise that for a given material, this ratio will be of significance in determining the spring constant of the resulting spring.

In preferred particular alternative, the leaves may be thicker at their midline and may be thinned or feathered towards their edges. It serves to concentrate the majority of the spring force to the midline for a better stability. Where the spring is to be located in a cylindrical housing, this is the portion of the spring that provides the majority of the restoring force.

According to a particular embodiment, the spring, including the one or more spring sections, the first valve element and second valve element are injection moulded from a plastomer. By providing a plastomer element, a spring may be obtained that is easy to injection mould. Unlike metal springs and valve elements, by the use of polymer materials, the spring valve combination may be made compatible with multiple different cleaning fluids, without the risk of corrosion or contamination.

Furthermore, recycling of the pump may be facilitated, given that other elements of the pump are also of polymer material. In one embodiment, all of the elements of the spring, including the first and second valve elements are injection moulded in situ i.e. in the mutual positions in which they will be used. In an alternative embodiment, integral injection moulding of all of the components may take place but a subsequent assembly/disassembly step may be required. In one embodiment, a biasing spring and ball valve may be integrally moulded with one part of the spring and subsequently separated and located at another part of the spring. In other words, a valve element for use within a valve chamber may be integrally formed outside of the valve chamber and subsequently inserted therein.

In particular embodiments, the spring and the other elements of the pump assembly may be formed of one and the same material class for the purposes of recycling. However, for each element a different material may be chosen to optimise the properties of each element of the combination.

As used herein, the term "plastomer" material is intended to include all thermoplastic elastomers that are elastic at ambient temperature and become plastically deformable at elevated temperatures, such that they can be processed as a melt and be extruded or injection moulded.

As indicated above, the material for the spring may be a plastomer. A plastomer may be defined by its properties, such as the Shore hardness, the brittleness temperature and Vicat softening temperature, the flexural modulus, the ultimate tensile strength and the melt index. Depending on, for example, the type of fluid to be dispensed, and the size and geometry of the pump body or spring, the plastomer material used in the pump may be varied from a soft to a hard material. The plastomer material forming at least the spring may thus have a shore hardness of from 50 Shore A (ISO 868, measured at 23 degrees C) to 70 Shore D (ISO 868, measured at 23 degrees C). Optimal results may be obtained using a plastomer material having a shore A hardness of 70-95 or a shore D hardness of 20-50, e.g. a shore A hardness of 75-90. Furthermore, the plastomer material may have brittleness temperature (ASTM D476) being lower than -50 degrees Celsius, e.g. from -90 to -60 degrees C, and a Vicat softening temperature (ISO 306/SA) of 30-90 degrees Celsius, e.g. 40 - 80 degrees C. The plastomers may additionally have a flexural modulus in the range of 15 - 80 MPa, 20 - 40 MPa or 30 - 50 MPa, or 25 - 30 MPa (ASTM D-790), e.g. 26-28 MPa. Likewise, the plastomers can have an ultimate tensile strength in the range of 3 - 11 MPa, or 5 - 8 MPa (ASTM D- 638). Additionally, the melt flow index may be at least 10 dg/min, or in the range of 20 - 50 dg/min (ISO standard 1133-1, measured at 190 degrees C). Suitable plastomers include natural and/or synthetic polymers. Particularly suitable plastomers include styrenic block copolymers, polyolefms, elastomeric alloys, thermoplastic

polyurethanes, thermoplastic copolyesters and thermoplastic polyamides. In the case of polyolefms, the polyolefin can be used as a blend of at least two distinct polyolefms and/or as a co-polymer of at least two distinct monomers. In an embodiment, plastomers from the group of thermoplastic polyolefin blends are used, such as from the group of polyolefin co-polymers. In particular embodiments, the plastomers are selected from the group of ethylene alpha olefin copolymers. Amongst these, ethylene 1-octene copolymers have been shown to be particularly suitable, especially those having the properties as defined above. Suitable plastomers are available from

ExxonMobil Chemical Co. as well as Dow Chemical Co.

Additionally, as a measure to allow the spring to be installed in the pump cylinder, the spring sections may have curved edges. The spring may then have a generally circular configuration, as viewed in the axial direction i.e. it may define a cylindrical outline. It will be understood that the curved edges may be sized such that the spring is cylindrical in its unstressed initial condition or in its compressed condition or at an intermediate position between these two extremes, for example in its compressed condition.

The precise configuration of the spring will depend on the characteristics required in terms of extension and spring constant. An important factor in determining the degree of extension of the spring is the initial geometry of the rhombus shapes of the spring sections. In one particular embodiment, the spring sections, in their initial condition, join at adjacent corners having an internal angle of between 90 and 120 degrees. In a fully relaxed spring, angle a may be between 60 to 160 degrees or 100 to 130 degrees, depending on the geometries and materials used for the spring as well as the pump body. The angle a is normally slightly higher when the spring is inserted into the pump chamber and in its initial stage before pump compression occurs, e.g. 5-10 degrees higher than for a fully relaxed spring. For a spring in its compressed condition, the angle a increases towards 180 degrees and for example may be 160 to 180 degrees in a compressed condition. For example, the angle a may be 120 degrees for a spring in an initial condition and 160 degrees for a spring in a compressed condition. A particularly desirable characteristic of the present spring is its ability to undergo a significant reduction in length. In particular embodiments, the spring sections are arranged to compress from an open configuration to a substantially flat configuration in which the spring sections or the leaves lie close against each other i.e. adjacent sides of the rhombus shaped spring sections become co-planar.

In a particular embodiment, each spring section may be able to compress axially to less than 60 %, or to less than 50 % of its uncompressed length. The overall reduction in length will depend on the number of spring sections and in actual operation, there may be neither need nor desire to compress each spring section to the maximum. The spring may comprise one spring section, two spring sections or multiple spring sections arranged in series. In a particular embodiment, the spring may comprise at least three spring sections which may be identical in geometry. A particular embodiment has five spring sections, which offers a good compromise between stability and range of compression.

According to an embodiment, the pump cylinder has a smaller diameter than the respective first and second valve elements, such that the valve elements are compressed in a radial direction and engage against the inner surface of the pump cylinder, such that an inner surface of the pump cylinder adjacent the respective valve element forms a valve seat. In another embodiment, the pump outlet comprises a bore for engagement of the second end portion and the bore has a smaller inner diameter than an outer diameter of the second valve element such that the second valve element is compressed in a radial direction within the bore and an interior of the bore adjacent the second valve element forms the second valve seat.

The spring may be slightly preloaded within the pump cylinder. Therefore, a length of the spring may be such that in the initial condition, the spring is retained within the pump cylinder in a slightly compressed state. Preloading the spring will assist in keeping the spring engaged with the piston portion.

Advantageously, because of the efficient design discussed above, the whole construction of the pump assembly may be achieved using just three components, namely the pump cylinder, the actuator and the spring valve combination, wherein the spring section and the first and second valve element are integrally formed. Such an integrally formed plastomer spring valve combination is believed to be new and inventive in its own right. Furthermore, although in particular embodiments the spring is formed to include both first and second valve elements forming both inlet and outlet valves, it will be understood that just one valve element need be integrally formed and the other element may be provided elsewhere, non-integrally connected or dispensed with, should it not be required.

The actuator may be formed as a single element although it will be understood that the piston portion and the dispenser portion may be separate elements, joined together either permanently or separably. Additionally, the feed conduit may be integrally formed with the pump cylinder or may be a separate item of manufacture. In such case, the pump assembly may comprise four or five components.

Various manufacturing procedures may be used to form the spring including injection moulding, thermoforming, 3D-printing and other methods. Some or all of the other elements forming the pump assembly may be manufactured by injection moulding. In a particular embodiment, the pump cylinder and the actuator may each be formed by injection moulding. They may all be of the same material or each may be optimised independently using different materials.

Additionally, although in one embodiment, the spring is manufactured of a single material, it is not excluded that it may be manufactured of multiple materials. As the spring is integrally formed to include inlet and/or outlet valves, the designer is faced with two conflicting requirements, to a large degree depending on the fluid that will be pumped:

1. The valves shall be flexible enough to allow for a good seal; and

2. The spring shall be stiff enough to provide the required spring constant to pump the fluid.

The skilled person will understand that these considerations may be achieved in a number of different ways. Thus using a single material there may be an optimum geometry where both conflicting requirements can be solved by the same material. In this case, the spring can be produced by means of standard single-component injection moulding. In an alternative, in order to alter the spring constant in relationship to the valve rigidity, the geometry of the spring may be altered so as produce a stiffer or softer spring. This may only be possible within certain boundaries since it may also impact the available volume of the pumping stroke.

If no solution to the above conflicting requirements can be achieved by altering the geometry, the material of the different parts can be changed, meaning that one or both valves may be made in a material different to that of the spring. Thus, the spring valve component can consist of up to three different materials. The spring may be made of a very stiff plastic material whereas the valves may be formed of soft plastic material. This may be accomplished using 2- or 3 -component moulding, over-molding or other advanced production techniques.

The stiffness of the spring and valves may be fine-tuned by adding a certain percentage of a stiffer material from the same chemical family to the original base plastomer material. In doing so a more robust soap with higher viscosity can be accommodated only by slightly stiffening the material while avoiding expensive and complex changes in the mould and component geometry.

It is thus clear that by modifying the material content, the same injection moulding tool for forming a given part of the pump assembly may be used for forming pumps for dispensing a wide variety of fluids.

The disclosure furthermore relates to a fluid dispenser comprising the pump assembly as described above, and a container for holding the fluid, wherein the second end of the feed conduit in use opens out below a fluid level in the container, and wherein the dispensing outlet connected to the pumping outlet is releasably connected to the container. Such a fluid dispenser can for instance be a dispenser for hand soap that is used in bathrooms and/or kitchens. Such a dispenser comprises a container with a closure in which closure the pump assembly is provided. The dispensing outlet is provided as a spout on the closure and is in fluid connection with the pump body. The dispensing outlet may be used to actuate the pump assembly by pressing the dispensing outlet downwards and thereby moving the first end portion of the spring towards the second end portion. The second valve element will open upon this movement, as described above, and fluid will be expelled from the pump body through the pump outlet towards the dispending outlet. By releasing the dispensing outlet, the spring expands and the first and second end portions will move away from each other. The first valve element will open upon this movement, as described above, and fluid will be sucked into the pump cylinder via the feed conduit through the pump inlet. Although in general, reference is made to top actuation by pushing down on the dispensing outlet, the skilled person will understand that the pump can operate in any desired orientation and that the dispenser can be designed accordingly. As such, references to up and down, top and bottom are for illustrative purposes and are not intended to be limiting on the scope of the invention.

The disclosure also relates to a dispenser for fluids comprising: a container having a body with a base and a neck provided with an opening; a pump cylinder supported within the neck, the pump cylinder having a lower end provided with a pump inlet and a feed conduit extending within the body of the container to the base; an actuator, the actuator comprising a piston portion slideably engaged within the cylinder and a dispenser portion extending therefrom and having a pump outlet channel extending therethrough from a pump outlet at the piston portion to a dispenser outlet in the dispenser portion; a closure element, encircling the piston portion and engaged with the neck to retain the pump cylinder and close the opening; an integrally- formed, plastomer spring provided within the pump cylinder, the spring having a first end engaged against the lower end of the pump cylinder and a second end engaged with the piston portion to bias the actuator upwards, the plastomer spring being provided with integrally formed inlet and outlet valves arranged to allow liquid to flow in a direction from the pump inlet to the pump outlet, wherein in use, the actuator can be depressed by a user with respect to the closure element to force the piston portion into the pump cylinder and displace liquid through the pump outlet and pump outlet channel. The disclosure further relates to the use of a plastomer spring having integrally- formed inlet and outlet valves in a top-actuated dispenser for fluids and a method of dispensing a fluid from a fluid pump as described above or hereinafter by exerting an axial force on the actuator to cause axial compression of the spring and a reduction in volume of the pump chamber, allowing the second valve element to open, such that fluid from the pump chamber flows through the pump outlet towards the dispensing outlet, while the first valve remains closed, releasing the axial force on the actuator to cause expansion of the spring and an increase in volume of the pump chamber, allowing the first valve element to open, such that fluid is sucked into the pump chamber through the feed conduit, while the second valve remains closed and subsequently, on release of the actuator, allowing to the spring to expand and create an under-pressure in the pump chamber. This under-pressure results in closure of the second valve element and opening of the first valve element, thus allowing fluid to flow through the feed conduit past the first valve element into the pump chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the present disclosure will be appreciated upon reference to the following drawings of a number of exemplary embodiments, in which:

Figure 1 shows a schematic cross-sectional view of an embodiment of a pump assembly in which the present disclosure as claimed in the appended claims may be implemented;

Figure 2 shows a schematic cross-sectional view of a fluid dispenser with the pump assembly of Figure 1.

Figure 3 shows the spring of Figures 1 and 2 in perspective view;

Figure 4 shows the spring of Figure 3 in front view;

Figure 5 shows the spring of Figure 3 in side view;

Figure 6 shows the spring of Figure 3 in bottom view;

Figure 7 shows the spring of Figure 3 in top view;

Figure 8 shows a schematic cross-sectional view of a fluid dispenser with a pump assembly according to a second embodiment;

Figure 9 shows part of the spring of Figure 8 in manufactured state;

Figure 10 shows a spring according to a third embodiment; and

Figure 11 shows part of the spring of Figure 10 in manufactured state. DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Figure 1 shows a perspective view of a pump assembly 100 in which the present disclosure as claimed in the appended claims may be implemented. The pump assembly 100 includes a pump cylinder 102 having a pump inlet 104 at a lower end for taking in the fluid. At the pump inlet 104, a feed conduit 106 with a first conduit end 108 and a second conduit end 110 is provided. The first conduit end 108 is connected to the pump inlet 104 and the second conduit end 110 opens out below a fluid level 210, see Figure 2. At an upper end of the pump cylinder 102 there is provided an outwardly extending flange 122 and a retention element 130, which protrudes inwardly from an inner surface 103 of the pump cylinder 102.

An actuator 111 of the pump assembly 100 includes a piston portion 112, slideably engaged within the pump cylinder 102 and a dispenser portion 114. The dispenser portion 114 extends from the piston portion 112, through which a pump outlet channel 116 extends from a pump outlet 118 at the piston portion 112 to a dispensing outlet 120 in the dispenser portion 114. The piston portion 112 includes a seal 126 slideably engaged against the inner surface 103 of the pump cylinder 102. The seal 126 extends around a circumference of the piston portion 112 whereby a pump chamber 128 is defined between the piston portion 112 and the pump cylinder 102. The retention element 130 is sized to allow the piston portion 112 to be inserted into the pump cylinder 102 but prevent its removal therefrom.

A spring 300 is provided within the pump cylinder 102. The spring 300 includes a number of spring sections 302, a first end portion 304 engaged against the lower end of the pump cylinder 102 and a second end portion 306 having a frusto-conical shaped body 324, engaged with the piston portion 112. The spring sections 302 can be compressed in the axial direction from an initial condition to a compressed condition and can subsequently expand to the initial condition to bias the piston portion 112 upwards.

A first valve element 308 is provided at the first end portion 304 of the spring 300, and a second valve element 310 is provided at the second end portion 306 of the spring. The spring sections 302, the first valve element 308 and the second valve element 310 are integrally formed of a plastomer material to form a spring valve combination. The first valve element 308 interacts with the inner surface 103 of the pump cylinder 102 to define a one-way inlet valve for the pump inlet 104 and the second valve element 310 interacts with the pump outlet channel 116 to define a oneway outlet valve towards the pump outlet 118.

Fig. 1 also depicts the engagement between the spring 300 and the pump cylinder 102. The first end portion 304 of the spring 300 is sized to fit within the pump cylinder 102 with a ring element 318 acting as an engaging member, engaged against the inner surface 103 of the pump cylinder 102 and the adjacent pump inlet 104. The first valve element 308 has an outer diameter that is slightly larger than the pump cylinder 102, whereby the first valve element 308 is slightly compressed in a radial direction against the inner surface 103 of the pump cylinder 102. This causes a slight pre-load to be applied, sufficient to maintain a fluid-tight seal in the absence of any external pressure. The inner surface 103 of the pump cylinder 102 adjacent the pump inlet 104 forms a first valve seat.

At the other end of the pump cylinder 102, the second end portion 306 engages within the pump outlet 118. The pump outlet 118 includes a bore 124 opening into the pump outlet channel, for engagement of the second end portion 306. The bore 124 is larger than the remainder of the pump outlet channel 116 but has a smaller inner diameter than an outer diameter of the second valve element 310 such that the second valve element 310 is compressed in a radial direction within the bore 124 and a slight pre-load is also applied, sufficient to maintain a fluid-tight seal in the absence of any external pressure. An interior of the bore 124 adjacent the second valve element 310 forms a second valve seat. The bore 124 extends into the pump outlet channel 116 to allow dispensing of the fluid 202 upon actuation of the pump assembly 100. The second end portion 306 is provided with a rib 322 serving as an engaging member between the second valve element 310 and the spring sections 302. The rib 322 has a greater diameter than the pump outlet 118 and serves to position the frusto-conical shaped body 324 and the second valve element 310 within the bore 124.

Figure 2 shows a fluid dispenser 1 with the pump assembly 100 of Figure 1. The dispenser 1 includes a container 200 having a body 201 with a base 204 and a neck 206 provided with an opening 208. The pump cylinder 102 of the pump assembly 100 is supported within the neck 206. The feed conduit 106 at the lower end of the pump cylinder 102 extends within the body of the container 200 to adjacent the base 204 and below a level 210 of liquid 202. A closure element 212 encloses an exterior of the pump cylinder 102, covering the outwardly extending flange 122. The closure element 212 engages with the neck 206 to retain the piston portion 112 within the pump cylinder 102 and close the opening 208. The closure element 212 and the neck 206 are provided with a snap fitting 215, such that the closure element 212 can be affixed to the container 200. By engaging the closure element 212 onto the neck 206, a first side of the flange 122 is pressed onto an upper edge of the neck 206, thereby centring the pump assembly 100 within the container 200. The closure element 212 has an opening in its centre to allow the dispenser portion 114 to pass through, such that a second side of the flange 122 is adjacent the closure element 212.

Figure 3 shows an enlarged perspective view of the spring 300, which is injection moulded in a single piece from ethylene octene material from ExxonMobil Chemical Co. The spring 300 includes a first end portion 304 and a second end portion 306 aligned with each other along an axis A and joined together by a plurality of rhombus shaped spring sections 302. In this embodiment, five spring sections 302 are shown although the skilled person will understand that more or less such sections may be present according to the spring constant required. Each spring section 302 includes four flat leaves 312, joined together along hinge lines 316 that are parallel to each other and perpendicular to the axis A. The leaves 312 have curved edges 328 and the spring sections 302 join at adjacent corners 314.

The first end portion 304 includes a ring element 318 and a cross-shaped support element 320. An opening 330 is formed through the ring element 318. The cross- shaped support element 320 is interrupted intermediate its ends by an integrally formed first valve element 308 that surrounds the first end portion 304 at this point.

The second end portion 306 has a rib 322 and a frusto-conical shaped body 324 that narrows in a direction away from the first end portion 304. On its exterior surface the frusto-conical shaped body 324 is formed with two diametrically opposed flow passages 326. At its extremity it is provided with an integrally formed second valve element 310 projecting conically outwardly and extending away from the first end portion 304.

Figures 4-7 are respective front, side and first and second end elevations of the spring 300.

Starting with Figure 4, the ring element 318 and cross-shaped support element 320 can be seen, together with the first valve element 308. In this view, it may be noted that the first valve element 308 is part spherical in shape and extends to an outer edge that is slightly wider than the cross-shaped support element 320. Also in this view, the rhombus shape of the spring sections 302 can be clearly seen. The spring 300 is depicted in its unstressed condition and the corners 314 define an internal angle a of around 115°. The skilled person will recognise that this angle may be adjusted to modify the spring properties and may vary from 60 to 160 degrees, from 100 to 130 degrees, or between 90 and 120 degrees. Also visible is the frusto-conical shaped body 324 of the second end portion 306 with rib 322, flow passages 326 and second valve element 310.

Figure 5 depicts the spring 300 in side view, viewed in the plane of the rhombus- shape of the spring sections 302. In this view, the hinge lines 316 can be seen, as can be the curved edges 328. It will be noted that the hinge lines at the corners 314, where adjacent spring sections 302 join, are significantly longer than the hinge lines 316 where adjacent flat leaves 312 join.

Figure 6 is a view onto the first end portion 304 showing the ring element 318 with the cross-shaped support element 320 viewed through opening 330. Figure 7 shows the spring 300 viewed from the opposite end to Figure 6, with the second valve element 310 at the centre and the frusto-conical shaped body 324 of the second end portion 306 behind it, interrupted by flow passages 326. Behind the second end portion 306, the curved edges 328 of the adjacent spring section 302 can be seen, which in this view define a substantially circular shape.

In use, operation of the fluid dispenser 1 is essentially the same as that of any other standard top-actuated dispenser. A user exerts a force downwards onto the actuator 111, causing the piston portion 112 to be pressed downwards into the pump cylinder 102 against the force of the spring 300. During this pumping stroke, any liquid 202 within the pump chamber 128 is subjected to an increased pressure, causing the second valve element 310 to deflect, whereby the liquid 202 can flow through the flow passages 326 to the pump outlet 118 and via the pump outlet channel 116 to the dispensing outlet 120. On releasing, the spring 300 expands, moving the piston portion 112 upwards and generating an under-pressure within the pump chamber 128. Liquid 202 from the container 200 is drawn in through the feed conduit 106 into the pump chamber 128. The first valve element 308 deflects to allow the liquid to pass, while the second valve element 310 closes again, preventing reflux of liquid from the pump outlet 118. Figure 8 shows a schematic cross-sectional view of a fluid dispenser 1001 with a pump assembly 1100 according to a second embodiment. Like elements to the first embodiment are provided with similar reference numerals preceded with 1000.

As in the case of the first embodiment shown in Figure 2, the dispenser 1001 includes a container 1200 having a body 1201 with a base 1204 and a neck 1206 provided with an opening 1208. The pump cylinder 1102 of the pump assembly 1100 is supported within the neck 1206. The feed conduit 1106 at the lower end of the pump cylinder 1102 extends within the body of the container 1200 to adjacent the base 1204 and below a level 1210 of liquid 1202. A closure element 1212 encloses an exterior of the pump cylinder 1102, covering the outwardly extending flange 1122. The closure element 1212 engages with the neck 1206 to retain the piston portion 1112 within the pump cylinder 1102 and close the opening 1208. The closure element 1212 and the neck 1206 are provided with a snap fitting 1215, such that the closure element 1212 can be affixed to the container 1200. By engaging the closure element 1212 onto the neck 1206, a first side of the flange 1122 is pressed onto an upper edge of the neck 1206, thereby centring the pump assembly 1100 within the container 1200. The closure element 1212 has an opening in its centre to allow the dispenser portion 1114 to pass through, such that a second side of the flange 1122 is adjacent the closure element 1212.

A spring 1300 is provided within the pump cylinder 1102. As in the previous embodiment, the spring 1300 includes a number of spring sections 1302, a first end portion 1304 engaged against the lower end of the pump cylinder 1102 and a second end portion 1306, engaged with the piston portion 1112. A first valve element 1308 is provided at the first end portion 1304 and a second valve element 1310 is provided at the second end portion 1306 of the spring. The spring sections 1302 and the second valve element 1310 are integrally formed of a plastomer material to form a spring valve combination.

The second embodiment of Figure 8 differs from the earlier embodiment of Figure 2 by the form of the first end portion 1304, which includes a captive first valve element 1308 provided within a valve chamber 1340. The valve chamber 1340 comprises a cylindrical valve support element 1320 and a lid 1342 having an inlet opening 1330 therethrough, aligned with the feed conduit 1106. The lid 1342 and the valve support element 1320 are integrally connected together by a living hinge 1344. The first valve element 1308 is biased towards the opening 1330 by an integral plastomer biasing spring 1346 and seats against a valve seat 1348 formed around the opening 1330 on inner surface of the lid 1342.

Figure 9 shows the first end portion 1304 of the spring 1300 of the second embodiment of Figure 8 in enlarged view in its manufactured state. As can be seen, the lid 1342 is attached to a ring element 1318 of the valve support element 1320 by hinge 1344. This allows both components to be integrally moulded together and subsequently hinged closed to form the valve chamber 1340. The first valve element 1308 and biasing spring 1346 are in this case separate from the valve support element 1320 and instead are connected to the upper spring section 1302 by a web 1345, that is subsequently broken during assembly. In this view, the construction of the first valve element 1308 can also be appreciated, having a generally bullet shape with a bore 1350 opening in a direction opposite to the biasing spring 1346. The bore 1350 limits the material thickness of the first valve element 1308 thus reducing possible component distortion during the injection moulding process.

For the purpose of manufacture, the spring 1300 including both the first and second valve elements 1308, 1310 and the lid 1342 can be integrally moulded in one piece. The first valve element 1308 can subsequently be detached by breaking the web 1345 and inserted into the valve chamber 1340, whereupon the lid 1342 may be closed onto the ring portion 1318. The lid 1342 and ring portion 1318 may connect with an interference fit, by adhesive, welding or any other appropriate means. They may also be held together once assembled by their location within e.g. a groove in the pump cylinder 1102 or by the force of the spring 1300.

Figure 10 shows a third embodiment of a spring 2300, in which like elements to the second embodiment are designated by similar references preceded by 2000. In

Figure 10, the spring 2300 is shown in a front elevation corresponding to the view of the spring in Figure 4. The spring 2300 is otherwise identical to the spring 1300, with the exception of the construction of the first end portion 2304. As can be seen in this view, the valve chamber 2340 is provided with outlet openings 2354 at front and back sides of a stirrup-shaped valve support element 2320, which terminates at its upper side in ring element 2318. The first valve element 2308 with its biasing spring 2346 can be seen within the valve chamber 2340. As in the second embodiment, the first end portion 2304 includes a lid 2342 connected to the ring element 2318 by a hinge 2344. Figure 11 shows the first end portion 2304 of the spring 2300 in enlarged cross sectional view. In this view, it may be appreciated that the biasing spring 2346 is integrally formed with the base of the valve chamber 2340. The outlet openings 2354 and the stirrup shape of the valve support element 2320 allow access of moulding tools to permit injection moulding of the spring 2300 in a single piece with the first valve element 2308 in position and the lid 2342 connected by hinge 2344. During assembly, the lid 2342 merely needs to be closed over the ring element 2318 as the spring 2300 is inserted into the pump cylinder.

Although in Figures 8 to 11, alternative valves have been shown for the first end portion of the spring, it will be understood that such valves may also be used at the second end portion as outlet valves from the pump chamber. Furthermore, although these figures use an integral lid 1342, 2342, it will be understood that the spring and first end portion may be manufactured without such a lid and that the first valve element may seal against an appropriate seat formed within the inlet of the pump cylinder or as part of the feed conduit.

It will be recognized that the embodiment discussed above is susceptible to various modifications and alternative forms well known to those of skill in the art. In particular, the pump assembly may be embodied for operation with different dispensers and in different orientations, distinct from the schematically illustrated design.

Many modifications in addition to those described above may be made to the structures and techniques described herein without departing from the scope of the invention. Accordingly, although specific embodiments have been described, these are examples only and are not limiting upon the scope of the invention