Patent Description:
Liquid dispensers for dispensing soaps and other similar fluids in liquid form are known. For various reasons in some applications, it is preferable to dispense soaps and other similar fluids in the form of a foam. Generally, in the form of a foam, less soap liquid is required to be used as contrasted with the soap in the liquid form. As well, soap as foam is less likely to run off a user's hands or other surfaces to be cleaned.

Relevant liquid dispensers are known in the art and are for example disclosed in <CIT>, <CIT> and <CIT>.

An object of the present invention is to provide an improved pump for dispensing a liquid.

Another object is to provide an improved pump for dispensing a liquid in the form of a foam.

Another object is to provide an improved pump with a bellows member to function as one or more of a displacement pump and a spring.

The present invention provides a pump for dispensing liquid from a reservoir comprising:.

Preferred embodiments of the invention are the subject matter of dependent claims <NUM>-<NUM>. Furthermore, described is a pump for dispensing liquid from a reservoir comprising:.

In another aspect, described is a pump for dispensing liquid from a reservoir comprising:.

Additionally, described is a spring member extending from a first end to a second end about a longitudinal axis,.

Furthermore described is a pump for dispensing liquid from a reservoir comprising:.

Further aspects and advantages of the present invention will become apparent from the following description taken together with the accompanying drawings showing inventive and disclosed but not claimed embodiments, in which:.

Reference is made first to <FIG>, <FIG> which show a first embodiment of a pump assembly generally indicated <NUM>. Pump assembly <NUM> is best shown in <FIG> as comprising two principal elements, a piston chamber-forming body <NUM> and a piston <NUM>.

The piston chamber-forming body <NUM> has three cylindrical portions illustrated to be of different radii, forming three chambers, an inner chamber <NUM>, an intermediate chamber <NUM>, and an outer chamber <NUM>, all coaxially disposed about an axis <NUM>. The intermediate cylindrical chamber <NUM> is of the smallest radii. The outer cylindrical chamber <NUM> is of a radius which is larger than that of the intermediate cylindrical chamber <NUM>. The inner cylindrical chamber <NUM> is of a radius greater than that of the intermediate cylindrical chamber <NUM> and, as well, is shown to be of a radius which is less than the radius of the outer cylindrical chamber <NUM>.

The inner chamber <NUM> has an inlet opening <NUM> and an outlet opening <NUM>. The inner chamber has a cylindrical chamber side wall <NUM>. The outlet opening <NUM> opens into an inlet end of the intermediate chamber <NUM> from an opening in a shoulder <NUM> forming an outer end of the inner chamber <NUM>. The intermediate chamber <NUM> has an inlet opening, an outlet opening <NUM>, and a cylindrical chamber side wall <NUM>. The outlet opening <NUM> of the intermediate chamber <NUM> opens into an inlet end of the outer chamber <NUM> from an opening in a shoulder <NUM> forming the inner end of the outer chamber <NUM>. The outer chamber <NUM> has an inlet opening, outlet opening <NUM> and a cylindrical chamber side wall <NUM>.

Piston <NUM> is axially slidably received in the body <NUM>. The piston <NUM> has an elongate stem <NUM> upon which four discs are provided at axially spaced locations. An inner flexing disc <NUM> is provided at an innermost end spaced axially from an intermediate flexing disc <NUM> which, in turn, is spaced axially from an outer sealing disc <NUM>. The inner disc <NUM> is adapted to be axially slidable within the inner chamber <NUM>. The intermediate disc <NUM> is adapted to be axially slidable within the intermediate chamber <NUM>.

The intermediate disc <NUM> has a resilient peripheral edge which is directed outwardly and adapted to prevent fluid flow inwardly yet to deflect to permit fluid flow outwardly therepast. Similarly, the inner disc <NUM> has a resilient outer peripheral edge which is directed outwardly and is adapted to prevent fluid flow inwardly yet to deflect to permit fluid flow outwardly therepast.

The outer sealing disc <NUM> is adapted to be axially slidable within the outer cylindrical chamber <NUM>. The outer sealing disc <NUM> extends radially outwardly from the stem <NUM> to sealably engage the side wall <NUM> of the outer chamber <NUM>, and prevent flow therepast either inwardly or outwardly.

The piston <NUM> essentially forms, as defined between the inner disc <NUM> and the intermediate disc <NUM>, an annular inner compartment <NUM> which opens radially outwardly as an annular opening between the discs <NUM> and <NUM>. Similarly, the piston <NUM> effectively forms between the intermediate sealing disc <NUM> and the outer sealing disc <NUM> an annular outer compartment <NUM> which opens radially outwardly as an annular opening between the discs <NUM> and <NUM>.

An outermost portion of the stem <NUM> is hollow with a central passageway <NUM> extending from an outlet <NUM> at the outermost end <NUM> of the stem <NUM> centrally through the stem <NUM> to a closed inner end <NUM>. A radially extending inlet <NUM> extends radially through the stem into the passageway <NUM>, with the inlet <NUM> being provided on the stem in between the outer disc <NUM> and the intermediate disc <NUM>. A foam inducing screen <NUM> is provided in the passageway <NUM> intermediate between the inlet <NUM> and the outlet <NUM>. The screen <NUM> may be fabricated of plastic, wire or cloth material. It may comprise a porous ceramic measure. The screen <NUM> provides small apertures through which an air and liquid mixture may be passed to aid foam production as by production of turbulent flow through small pores or apertures of the screen thereof in a known manner.

The piston <NUM> also carries an engagement flange or disc <NUM> on the stem <NUM> outward from the outer sealing disc <NUM>. Engagement disc <NUM> is provided for engagement by an activating device in order to move the piston <NUM> in and out of the body <NUM>.

In a withdrawal stroke with movement from the retracted position of <FIG> to the extended position of <FIG>, the volume between the inner disc <NUM> and the intermediate disc <NUM> decreases such that fluid is displaced outwardly past the intermediate disc <NUM> to between the intermediate disc <NUM> and the outer disc <NUM>. At the same time, the volume between the intermediate disc <NUM> and the outer disc <NUM> increases, with such increase being greater than the volume decrease between the inner disc <NUM> and the intermediate disc <NUM> such that in addition to the fluid displaced outwardly past intermediate disc <NUM>, air is drawn inwardly via the outlet <NUM>, passageway <NUM>, and the inlet <NUM> in between the intermediate disc <NUM> and the outer disc <NUM>.

In a retraction stroke from the position of <FIG> to the position of <FIG>, the volume between the intermediate disc <NUM> and the outer disc <NUM> decreases such that air and liquid therebetween and in the passageway <NUM> above the screen <NUM> is forced under pressure out through the screen <NUM> commingling and producing foam. At the same time, in the retraction stroke, the volume between the inner disc <NUM> and the intermediate disc <NUM> increases drawing liquid from inside a container past the inner disc <NUM>. Reciprocal movement of the piston <NUM> between the retracted and extended positions will successively draw and pump precise amounts of fluid from a container and mix such fluid with air from the atmosphere and dispense the fluid commingled with the air as a foam.

Operation of the pump assembly illustrated in <FIG> will draw liquid out of a container creating a vacuum therein. The pump assembly is preferably adapted for use with a collapsible container. Alternatively, a suitable vent mechanism may be provided if desired as, for example, for use in a non-collapsible container to permit atmospheric air to enter the container and prevent a vacuum being built up therein which prevents further dispensing.

It is to be appreciated that the inner disc <NUM> and the intermediate disc <NUM> form a first stepped pump and, similarly the intermediate disc <NUM> and the outer disc <NUM> form a second stepped pump. The first pump and second pump are out of phase in the sense that in any one retraction or extension stroke while one pump is drawing fluid in, the other is discharging fluid out.

Both the piston <NUM> and the body <NUM> may be formed as unitary elements from plastic as by injection moulding.

Reference is now made to <FIG> which shows a liquid soap dispenser generally indicated <NUM> utilizing the pump assembly <NUM> of <FIG> secured in the neck <NUM> of a sealed, collapsible container or reservoir <NUM> containing liquid hand soap <NUM> to be dispensed. Dispenser <NUM> has a housing generally indicated <NUM> to receive and support the pump assembly <NUM> and the reservoir <NUM>. Housing <NUM> is shown with a back plate <NUM> for mounting the housing, for example, to a building wall <NUM>. A bottom support plate <NUM> extends forwardly from the back plate to support and receive the reservoir <NUM> and pump assembly <NUM>. As shown, bottom support plate <NUM> has a circular opening <NUM> therethrough. The reservoir <NUM> sits supported on shoulder <NUM> of the support plate <NUM> with the neck <NUM> of the reservoir <NUM> extending through opening <NUM> and secured in the opening as by a friction fit, clamping and the like. A cover member <NUM> is hinged to an upper forward extension <NUM> of the back plate <NUM> so as to permit replacement of reservoir <NUM> and its pump assembly <NUM>.

Support plate <NUM> carries at a forward portion thereof an actuating lever <NUM> journalled for pivoting about a horizontal axis at <NUM>. An upper end of the lever <NUM> carries a hook <NUM> to engage engagement disc <NUM> and couple lever <NUM> to piston <NUM>, such that movement of the lower handle end <NUM> of lever <NUM> from the dashed line position to the solid line position, in the direction indicated by arrow <NUM> slides piston <NUM> inwardly in a retraction pumping stroke as indicated by arrow <NUM>. On release of the lower handle end <NUM>, spring <NUM> biases the upper portion of lever <NUM> downwardly so that the lever draws piston <NUM> outwardly to a fully withdrawn position as seen in dashed lines in <FIG>. Lever <NUM> and its inner hook <NUM> are adapted to permit manual coupling and uncoupling of the hook <NUM> as is necessary to remove and replace reservoir <NUM> and pump assembly <NUM>. Other mechanisms for moving the piston can be provided including mechanised and motorized mechanisms.

In use of the dispenser <NUM>, once exhausted, the empty, collapsed reservoir <NUM> together with the attached pump <NUM> are removed and a new reservoir <NUM> and attached pump <NUM> may be inserted into the housing. Preferably, the removed reservoir <NUM> with its attached pump <NUM> are both made entirely out of recyclable plastic material which can easily be recycled without the need for disassembly prior to cutting and shredding.

Reference is now made to <FIG> which illustrate a second embodiment of a pump assembly. Throughout the drawings, the same reference numerals are used to refer to like elements.

<FIG> also shows a pump assembly <NUM> having a piston chamber-forming body <NUM> and a piston <NUM>. The piston chamber-forming body <NUM> is adapted to be threadably secured to the neck of a bottle or reservoir not shown.

The body <NUM> is formed with a cylindrical outer tubular portion <NUM> connected at an inner end via a radially extending flange portion <NUM> to a cylindrical inner tubular portion <NUM>. The inner tubular portion <NUM> extends axially radially inside the outer tubular portion <NUM>. The body <NUM> also carries on its flange portion <NUM> an inward axially extending generally cylindrical support tube <NUM> adapted to support an air chamber-forming member <NUM>. Member <NUM> has a cylindrical side wall <NUM> and is closed at its inner end by end wall <NUM>. Openings <NUM> are provided aligned through the wall <NUM> to provide communication from the interior of the reservoir into the interior of the member <NUM> and hence into the inner chamber <NUM> as indicated by arrow <NUM>.

The outer chamber <NUM> is formed radially inwardly of the outer tubular portion <NUM> having a side wall <NUM> thereabout and open at its outlet opening <NUM>. As shown, the side wall <NUM> tapers outwardly at chamfers proximate the outlet opening <NUM> to facilitate entry of the piston <NUM>.

The intermediate chamber <NUM> is formed radially inwardly of the inner tubular portion <NUM>. The inner tubular portion <NUM> defines an outlet opening <NUM> of the intermediate chamber <NUM> and a side wall <NUM> thereof. The intermediate chamber <NUM> has its side wall <NUM> taper outwardly as a chamfer proximate the outlet opening <NUM> to facilitate entry of the piston <NUM> into the intermediate chamber <NUM>.

The inner chamber <NUM> is formed radially inwardly of the cylindrical support tube <NUM>. The cylindrical support tube <NUM>, inner tubular portion <NUM>, outer tubular portion <NUM>, inner chamber <NUM>, intermediate chamber <NUM> and outer chamber <NUM> are each coaxial about axis <NUM>.

The piston <NUM> is formed from five elements which are secured together as a unit. These elements include elements, namely, an outer casing <NUM>, an inner core <NUM>, a foam producing element, an engagement disc <NUM> and an air pump disc <NUM>.

The foam producing element is a combination of two screens <NUM> and <NUM> and a three-dimensional basket-like screen <NUM> having generally frustoconical walls with small openings therethrough as in the manner of known filter members.

The piston <NUM> carries at its inner end the air pump disc <NUM> fixedly supported by a hollow neck tube <NUM> being fixedly secured within a hollow support tube <NUM> of the inner core <NUM>. The neck tube <NUM> defines a passageway <NUM> therethrough open at both ends.

The air pump disc <NUM> includes a locating flange <NUM> to locatably engage the cylindrical side wall <NUM> and a resilient flexible circular sealing disc <NUM> which sealably engages the side wall <NUM> and prevents flow of fluids axially outwardly therepast. An air chamber <NUM> is defined between the air chamber-forming member <NUM> and the air pump disc <NUM> which will increase and decrease in volume as the piston <NUM> is moved axially in the body <NUM> between the extended and retracted positions. The air chamber <NUM> is in communication with the passageway <NUM> via the neck tube <NUM>.

The outer casing <NUM> is of enlarged diameter at its axially inner end where the outer disc <NUM> is provided. The outer disc <NUM> is shown as including a locating flange <NUM> to locatably engage the cylindrical side wall <NUM> of the outer chamber <NUM> and a resilient flexible circular sealing flange <NUM> which sealably engages the side wall <NUM> and prevents flow of fluids axially outwardly therepast.

The outer casing <NUM> is shown with the outer disc <NUM> carried as a radially outwardly extending flange on a cylindrical large tube portion <NUM> which extends axially outwardly to a radially inwardly extending shoulder <NUM> supporting a small tube portion <NUM> extending axially outwardly from the shoulder <NUM> to the outlet <NUM>. Screens <NUM>, <NUM> and <NUM> are located on the shoulder <NUM> sandwiched between the shoulder and the outer end of the inner core <NUM>.

The inner core <NUM> carries the inner disc <NUM> and the intermediate disc <NUM>. Each of the inner disc <NUM> and intermediate disc <NUM> comprise circular resilient flexible discs each of which extends radially outwardly and toward the outlet <NUM>. The inner disc <NUM>, when engaged with the inner chamber <NUM>, that is, with the cylindrical side wall of the cylindrical support tube <NUM>, prevent fluid flow axially inwardly therepast through the inner chamber <NUM>, however, is adapted to have its resilient outer edge deflect radially inwardly to permit fluid flow, under pressure differentials above a predetermined pressure, axially outwardly therepast. The intermediate flexible disc <NUM>, when engaged with the intermediate chamber <NUM>, that is, with the interior wall of the inner tubular portion <NUM>, prevents fluid flow axially inwardly therepast through the intermediate chamber <NUM>, however, is adapted to have its resilient outer edge deflect radially inwardly to permit fluid flow, under pressure differentials above a predetermined pressure, axially outwardly therepast.

The inner disc <NUM> has its outer periphery extending outwardly so as to engage the cylindrical inner wall of the support tube <NUM> so as to prevent fluid flow inwardly therepast. The other periphery of the inner sealing disc <NUM> is, however, sufficiently resilient that it can deflect radially inwardly away from the support tube <NUM> to permit fluid flow therepast outwardly. Similarly, the intermediate disc <NUM> has its resilient periphery extend outwardly and engage the cylindrical interior wall of the inner tubular portion <NUM> so as to prevent fluid flow inwardly therepast yet is sufficiently resiliently deflectable so as to permit fluid flow outwardly therepast.

The inner core <NUM> has the passageway <NUM> which is open at both an axial inner end and open at an axial outer end. The inner core <NUM> includes a cylindrical lower portion <NUM> which has a plurality of flutes at circumferentially spaced locations thereabout which effectively form with the outer casing <NUM> peripheral passageways <NUM> which extend axially. Passageways <NUM> are open to the outer compartment <NUM> between discs <NUM> and <NUM> at the inner ends of the passageways. At the outer ends, the passageways <NUM> join radial inlets <NUM> in the lower portion <NUM> which provide communication into the central passageway <NUM>.

The piston <NUM> provides a central flow path for flow of fluids in the passageway <NUM>, through the screens <NUM>, <NUM> and <NUM> and, hence, through the smaller tube portion <NUM> to the outlet <NUM>. The piston <NUM> provides another flow path for flow of fluid from the outer compartment <NUM> via peripheral passageways <NUM> and inlets <NUM> into the passageway <NUM>. This pathway permits fluid flow both inwardly and outwardly and is particularly adapted to receive any liquid which under gravity flows down to the lower and axially outermost portion of the outer compartment <NUM> where the openings to the peripheral passageways <NUM> are provided.

Operation of the second embodiment of <FIG>, other than in respect of the air pump disc <NUM>, is similar to that with the first embodiment of <FIG>.

In movement of the piston <NUM> in a withdrawal stroke from a retracted position as illustrated in <FIG> to the extended position illustrated in <FIG>, of course, with the cover <NUM> shown in <FIG> having been removed, fluid between the inner disc <NUM> and the intermediate disc <NUM> is forced outwardly past the intermediate disc <NUM> because the volume between the discs <NUM> and <NUM> decreases with outward movement of the piston <NUM>.

In the withdrawal stroke of the piston, atmospheric air is drawn inwardly via the outlet <NUM> and passageway <NUM> into the air chamber <NUM> and, at the same time, in between the intermediate disc <NUM> and the outer disc <NUM> via inlets <NUM> and passageways <NUM>.

Air is drawn into the area between the larger diameter outer disc <NUM> and the smaller diameter intermediate disc <NUM> since the volume between the discs <NUM> and <NUM> increases as the piston <NUM> is drawn outwardly.

In a retraction stroke, the volume between the inner disc <NUM> and the intermediate disc <NUM> increases and since intermediate disc <NUM> prevents fluid flow outwardly therepast, a vacuum is created which deflects the inner disc <NUM> so as to draw fluid from the container as indicated by arrow <NUM> through inlet <NUM> and hence outwardly past the deflecting inner disc <NUM>. In the retraction stroke, the volume between the outer disc <NUM> and the intermediate disc <NUM> decreases and, thus, any air or liquid therebetween is forced out passageway <NUM> and inlet <NUM> to pass outwardly through the passageway <NUM>, through the screens to the outlet <NUM>. At the same time in the retraction stroke, air from the air chamber <NUM> is forced outwardly via the passageway <NUM> to also pass outwardly through the screen <NUM>.

Operation of the pump illustrated in <FIG> will draw liquid out of a container creating a vacuum therein.

As shown in <FIG>, the outer disc <NUM> includes a resilient sealing flange <NUM> which is formed as a thin resilient flange having an elastically deformable edge portion near the side wall <NUM> of the outer chamber <NUM>. This edge portion of the sealing flange <NUM> is deflectable radially inwardly so as to permit, under a sufficiently high vacuum differential, air to flow axially inwardly therepast. Preferably, the piston <NUM> may be configured such that substantially all air to be drawn inwardly is drawn inwardly via the outlet <NUM>, however, a device could be arranged such that the restriction to flow through the screens <NUM>, <NUM> and <NUM> is such that some proportion or substantially all the air is drawn past the sealing flange <NUM>. The locating flange <NUM> on the outer disc <NUM> is preferably provided to permit fluid flow therepast but could be configured to prevent fluid flow inwardly and/or outwardly. Other embodiments are possible in which a one-way valve mechanism is provided in outlet tube <NUM> which prevents flow back through the outlet <NUM>.

In sliding of the piston <NUM> in an extension stroke from the retracted position shown in <FIG> towards an extended position, fluid, notably air from the outlet <NUM> but also possibly liquid and/or foam in the outlet tube <NUM> and passageway <NUM>, is drawn upwardly into the air chamber <NUM> at the same time as liquid, foam and/or air is drawn into the lower compartment <NUM>. In sliding of the piston <NUM> from in a retraction stroke to the extended position to the retracted position, air and/or other foam or fluid in the air chamber <NUM> is pressurized and forced outwardly through the passageway <NUM> through the screens. The air pump disc <NUM> provides for inhalation and expulsion of fluids, notably air, in addition to the quantities of fluid inhaled and expulsed by the remainder of the pump assembly and, thus, the air pump disc <NUM> increases the volume of air which is available to be forced through the screens to produce foam. The configuration shown has an air pump <NUM> comprising the air chamber-forming member <NUM> and the air pump disc <NUM> inward from the remainder of the pump assembly <NUM> and of a diameter not exceeding that of the outer tubular portion <NUM>. This is an advantageous configuration to provide additional air pumping capacity with the same piston stroke in a device which can be inserted into the mouth of a reservoir.

The inner disc <NUM> and intermediate disc <NUM> form a first stepped pump. The intermediate disc <NUM> and the outer disc <NUM> form a second stepped pump, out of phase with the first pump. The air pump <NUM> is in phase with the second pump and out phase with the first pump.

<FIG> shows, in addition to the two screens <NUM> and <NUM> to produce foam, a three-dimensional basket-like screen <NUM> having generally frustoconical walls with small openings therethrough as in the manner of known filter members. Only one of the three screens needs to be provided. Other porous members to produce foam may be used.

In <FIG>, only one passageway <NUM> and inlet <NUM> is shown to provide communication from the outer compartment <NUM> to the passageway. Other passageways may be provided to provide communication from the outer compartment <NUM> to the passageway <NUM>.

It is to be appreciated that the nature of the liquid to be dispensed including its viscosity and flow characteristics will be important in order for a person skilled in the art to make suitable selection of the relative sizes and dimensions and resistance to flow provided by the various passageways, inlets, outlets and screens and/or past the various discs. As well, the quantity of liquid desired to be dispensed in each stroke will have a bearing on the relative proportion and sizing of the components including particularly the inner compartment <NUM>, outer compartment <NUM> and the axial length of a stroke of the piston.

In the preferred embodiments, the engagement disc <NUM> is provided on the piston <NUM> for engagement to move the piston inwardly and outwardly. It is to be appreciated that various other mechanisms can be provided for engagement and movement of the piston relative the body <NUM>.

The preferred embodiments show dispensers for passing liquid and air through screens <NUM>, <NUM> and <NUM> to dispense the liquid as a foam. The screens <NUM>, <NUM> and <NUM> can be eliminated in which case the dispenser illustrated could serve to dispense liquid with air. The foaming screens could be replaced by another orifice device such as an atomizing nozzle to produce a mist or spray.

The preferred embodiments show passages for dispensing of the air and/or liquid as being provided internally within a piston. Such an arrangement is believed preferred from the point of view of ease of construction of the pump assembly <NUM>. However, it is to be appreciated that passageways for dispensing the liquid and/or foam may be provided, at least partially, as part of the body <NUM> or removably mounted to the body <NUM>.

In accordance with the preferred embodiment illustrated, the relative buoyancy of air within the liquid and, hence, the separation of air and liquid due to gravity are utilized as, for example, to permit air in the compartment <NUM> to flow upwardly into the reservoir <NUM> and liquid in the reservoir <NUM> to flow downwardly into the inner compartment <NUM> as, for example, when the inner compartment <NUM> is open to the reservoir. It is to be appreciated, therefore, that the pump assembly should typically be disposed with what has been referred to as the inner end of the pump assembly at a height above the height of the outer outlet end.

Reference is made to <FIG> which show a third embodiment of a pump assembly. The pump assembly of the embodiment of <FIG> is identical to the embodiment of <FIG>, however, the piston chamber forming body <NUM> is formed of two separate members, an outer body member <NUM> and an inner body member <NUM> which are adapted to move axially relative to each other. In this regard, the outer body member <NUM> is an annular ring which is circular in cross-section and has a radially inwardly extending flange <NUM> at its inner end which defines the cylindrical chamber side wall <NUM> of the inner chamber <NUM>. The flange <NUM> ends at a shoulder <NUM> with the outer body member <NUM> extending axially therefrom as a ring-like portion <NUM> whose radially inwardly directed surface carries threads <NUM>. The inner body member <NUM> is an annular member which is circular in cross-section and defines internally thereof the intermediate chamber <NUM> and the outer chamber <NUM>. As well, the inner body member <NUM> carries and defines the shoulder <NUM> which forms an outer end of the inner chamber <NUM>. The inner body member <NUM> has a lower portion <NUM> carrying a cylindrical outer surface which is threaded with threads which match with and engage the threads on the outer body member <NUM> such that relative rotation of the body members <NUM> and <NUM> will axially move the body members <NUM> and <NUM> relative to each other. The inner body member <NUM> has a shoulder <NUM> on its outside surface in opposed relation to the shoulder <NUM> on the outer body member <NUM>. Inward of the shoulder <NUM>, the inner body member <NUM> has a circumferential outer wall <NUM> which is adapted to sealably engage with a radially inwardly directed cylindrical wall <NUM> of the flange <NUM> of the outer body member <NUM> so as to form a seal therebetween. As to be seen in the comparison between <FIG>, with relative axial movement of the inner body member <NUM> and outer body member <NUM>, the axial extent of the outer chamber <NUM> may be varied, however, the intermediate chamber <NUM> and the outer chamber <NUM> are not changed. The embodiment of <FIG> shows an arrangement in which the piston <NUM> moves through the stroke indicated being an axial distance represented by the letter S. In the fully retracted position as illustrated in dotted lines in <FIG>, the inner disc <NUM> is intended to be maintained in a sealed condition with the side walls of the inner chamber <NUM> thus preventing fluid flow outwardly therepast. The volume of fluid which will be drawn from the reservoir in each cycle of the piston will be determined by the length of the stroke times the difference in the cross-sectional area between the inner chamber <NUM> and the intermediate chamber <NUM>. Referring now to <FIG>, the axial extent of the inner chamber <NUM> has been reduced. The stroke of the piston in <FIG> is the same as in <FIG> and is also indicated by S. However, in each complete cycle of the piston, the volume of fluid to be drawn from the reservoir is represented merely by the axial extent of the inner chamber <NUM> that the inner disc <NUM> is in sealed engagement therewith which is merely a fraction of the axial extent that the inner disc is in sealed engagement with the inner chamber in <FIG>. Thus, it is to be appreciated, that by axial movement of the inner chamber member <NUM> relative to the outer chamber member <NUM>, the amount of fluid dispensed in each complete stroke can be varied, however, since the displacement of the pump between the intermediate disc <NUM> and outer disc <NUM> has not changed, effectively, the relative volume of liquid dispensed to air dispensed in each stroke can be varied for a constant length stroke of the piston.

Referring to <FIG>, it is to be appreciated that when the inner disc <NUM> is inwardly of the inner chamber <NUM> such that the inner disc <NUM> is no longer in engagement with the inner chamber <NUM>, then the inner disc <NUM> does not prevent fluid flow from the reservoir into or out of the inner chamber <NUM>.

Reference is made to <FIG> and <FIG> which illustrate a fourth embodiment. The piston <NUM> and body <NUM> in <FIG> and <FIG> have identical features to those illustrated in the first embodiment of <FIG>, however, with different proportions in the axial direction and with the cylindrical outer surface of the body <NUM> threaded so as to threadably engage with an annular support ring <NUM> which carries mating threads on its cylindrical interior surface. The support ring <NUM> is to be located in a fixed position relative to the support plate <NUM> of the dispenser as shown in <FIG> such that the support ring <NUM> will be in a fixed position relative to the lever <NUM>. By rotating the body <NUM> about its axis, the axial, that is, vertical location as seen in <FIG>, of the body <NUM> can be varied. However, with the lever <NUM> fixed in position relative to the support ring, it follows that the piston <NUM> which is held by the lever <NUM> is held in a fixed position relative to the support ring <NUM>.

Referring to <FIG>, the position of the piston <NUM> is illustrated in an extended position in solid lines and in a retracted position in dotted lines. The movement of the piston axially from the extended position to the retracted position is the axial length of a single stroke of constant fixed length indicated as S. In <FIG>, during the entire stroke, the inner disc <NUM> is retained within the inner chamber <NUM>.

Referring to <FIG> illustrates a position in which the body <NUM> has been moved axially outwardly relative to the support ring <NUM>. As shown, in comparing <FIG> and <FIG>, in <FIG>, the body <NUM> extends from the support ring <NUM> a distance X whereas in <FIG>, the body <NUM> extends from the support ring a distance equal to X plus Y. In each of the embodiments, the axial distance of the engagement flange <NUM> from the ring support <NUM> is a constant distance represented as Z. In the embodiment of <FIG>, in the retracted position, the inner disc <NUM> is axially inwardly of the inner chamber <NUM> and thus does not prevent flow of liquid from the reservoir inwardly or outwardly of the inner chamber <NUM>. In a cycle of the piston <NUM> in <FIG> through a constant stroke indicated as S, there is effectively pumping for an axial distance that the inner disc <NUM> passes from first coming to seal the inlet end of the inner chamber <NUM> to the position of the inner disc <NUM> in the extended position of the stroke indicated in solid lines in <FIG>.

In describing <FIG> and <FIG>, the position of the piston <NUM> in a retracted position is defined as an indexing position. From this indexing position, the piston <NUM> is moved in each stroke relative to the body <NUM> to the extended position and then back to the indexing (retracted) position. In the pump of <FIG> and <FIG>, <FIG> illustrates the pump <NUM> in a first indexing condition with the piston <NUM> having a first indexing position relative to the body <NUM>. In a cycle of operation involving one retraction stroke and one extension stroke, for a fixed length of stroke indicated as S, a first fixed volume of fluid is drawn from the reservoir and displaced past the intermediate disc <NUM>. The pump is capable of assuming other indexing configurations such as the one indicated in <FIG> in which the piston is in a different indexing position than the indexing position of <FIG>. For the same fixed length stroke of the piston, the volume of liquid discharged past the intermediate disc <NUM> is equal to a different amount having regard to the relative proportion of the stroke that the inner disc <NUM> engages the inner chamber <NUM> to prevent fluid flow inwardly therepast. The axial movement of the body <NUM> relative to the support ring <NUM> provides an indexing adjustment mechanism to change the indexing position of the piston <NUM> so as to change the volume dispensed.

Reference is now made to <FIG> which shows a fifth embodiment with the piston <NUM> in a fully extended position in solid lines in a fully retracted position in dashed lines. The piston <NUM> is identical to the piston of the embodiment of <FIG>. The body <NUM> is similar, however, the axial length of the inner chamber <NUM> and the intermediate chamber <NUM> have been reduced. As seen in the extended position in solid lines, the intermediate disc <NUM> extends outwardly beyond the intermediate chamber <NUM> and the inner disc <NUM> is engaged in the inner chamber <NUM>. In the extended position, air from outer chamber <NUM> may flow inwardly past the intermediate disc <NUM> to between the intermediate disc <NUM> and the inner disc <NUM> and fluid may flow outwardly past the intermediate disc <NUM>. When in the retracted position as illustrated in dashed lines, the inner disc <NUM> is inwardly beyond the inner chamber <NUM> and the intermediate disc <NUM> is engaged in the intermediate chamber <NUM>. Air which may be between the intermediate disc <NUM> and the inner disc <NUM> may, under gravity, move upwardly so as to enter a bottle or other reservoir disposed above the pump <NUM>, and fluid from the reservoir may flow downwardly to fill the inner chamber <NUM>. This configuration can have the advantage of being capable of being used with a non-collapsible, rigid container so as to provide an allotment of air into a reservoir in each stroke which can assist in preventing a vacuum from being developed inside the reservoir. The pump of <FIG>, in fact, can positively pump air into the reservoir. The extent to which either the inner disc <NUM> extends inwardly past the inner chamber <NUM> and the extent the intermediate disc <NUM> extends outwardly past the intermediate chamber <NUM> can assist in determining the amount of air that may pass upwardly into the reservoir.

Reference is made to <FIG> which shows a sixth embodiment with the piston <NUM> in a fully extended position in solid lines and in a retracted position in dashed lines. The pump assembly <NUM> of <FIG> is the same as that of <FIG> but modified to remove the intermediate disc <NUM> from the piston <NUM> and to provide an equivalent flexible annular intermediate disc or flange <NUM> to extend inwardly from the body <NUM> within the intermediate chamber <NUM>. In this regard, the piston <NUM> has its stem <NUM> to be of a constant diameter between the inner disc <NUM> and the outer disc <NUM>. The piston <NUM> is also shown to be constructed of two parts, an inner portion <NUM> carrying the inner disc <NUM> and an outer portion <NUM> carrying the outer disc <NUM>.

The intermediate flange <NUM> extends radially outwardly and downwardly and has a flexible outer periphery which engages the stem <NUM> between the inner disc <NUM> and the outer disc <NUM> to prevent fluid flow inwardly therepast yet which is resiliently deflectable radially outwardly to permit fluid flow outwardly therepast. In each of the embodiments of <FIG>, the intermediate disc <NUM> may be replaced by an intermediate flange <NUM> as in <FIG>. Similarly, in each of the embodiments of <FIG>, the inner disc <NUM> may be replaced by a similar intermediate flange to extend inwardly from the inner chamber <NUM>.

<FIG> illustrate a first version in which the inner chamber <NUM> is of a greater diameter than the intermediate chamber <NUM> and the intermediate chamber <NUM> is of a greater diameter than the outer chamber <NUM>.

Reference is now made to <FIG> which illustrate a second version of the pump assembly in which the inner chamber <NUM> is of a smaller diameter than the intermediate chamber <NUM> and the intermediate chamber <NUM> is of a smaller diameter than the outer chamber <NUM>. The piston illustrated in each of <FIG> has components identical to the components illustrated in <FIG>, however, with a notable difference that the inner disc <NUM> is smaller than the intermediate disc <NUM>. <FIG> illustrates a seventh embodiment in which the inner disc <NUM> and the intermediate disc <NUM> form a first stepped pump and the intermediate disc <NUM> an the outer disc <NUM> form a second stepped pump. The two stepped pumps are in phase in a sense that both operate to discharge fluid outwardly on a retraction stroke and to draw fluid in between their respective discs on an extension stroke. In an extension stroke, the inner pump effectively serves to draw liquid from the reservoir and between the inner disc <NUM> and the intermediate disc <NUM> and to discharge it past the intermediate disc <NUM> between the intermediate disc <NUM> and the outer disc <NUM>. The second pump serves to draw air inwardly into between the intermediate disc <NUM> and the outer disc <NUM> in a withdrawal stroke and to discharge liquid and air outwardly through the outlet <NUM> in a retraction stroke.

Reference is made to <FIG> which illustrates an eighth embodiment which is identical to the embodiment shown in <FIG> with the exception that the axial length of the inner chamber <NUM> is reduced to an extent that in the retracted position illustrated in dashed lines in <FIG>, the inner disc <NUM> extends inwardly beyond the inner chamber <NUM>. In the embodiment of <FIG>, compared to that of <FIG>, the fluid drawn from the reservoir in each cycle of the piston, will be reduced having regard to the axial extent in each stroke that the inner disc <NUM> is in engagement with the inner chamber <NUM>.

<FIG> and <FIG> illustrate a ninth embodiment of the second version of the pump having an arrangement similar to that illustrated in <FIG> and <FIG> of the first version with the body <NUM> being elongated and threadably received within a locating ring <NUM> such that relative axial displacement of the body <NUM> relative to the ring <NUM> will vary the volume of liquid that is drawn into the pump from the reservoir in each cycle of the pump. In comparison of <FIG>, with the ring support member <NUM> fixed relative to the dispenser support member <NUM> and the pivot point of the lever <NUM>, the body <NUM> is moved inwardly from the position of <FIG> to the position of <FIG> by an axial distance equal to Y. Each of <FIG> and <FIG> shows movement of an identical piston through an identical equal stroke distance indicated S.

Reference is made to <FIG> which illustrates a tenth embodiment similar to <FIG>, however, in this embodiment not only in the retraction position is the inner disc <NUM> inward of the inner chamber <NUM> but, in addition, in the withdrawal position, the intermediate disc <NUM> is outward of the intermediate chamber <NUM>. The embodiment of <FIG> can be used with a non-collapsible bottle in that in each stroke, some quantity of air can be permitted to pass firstly when the pump is in the extended position from between the outer disc <NUM> and the intermediate disc <NUM> inwardly past the intermediate disc <NUM> and, subsequently, when the piston is in the retracted position to pass from between the intermediate disc <NUM> and the inner disc <NUM> to past the inner disc <NUM> and into the reservoir. Relative selection of when each of the discs <NUM> and <NUM> come to disengage from their respective chamber and their relative sizes of the different chambers can be used to determine the amount of air which may be permitted to be passed back into a reservoir in any stroke. Preferably, as shown, at all times, at least one of the inner disc and the intermediate disc <NUM> are in engagement with their respective chamber to prevent fluid flow outwardly.

Reference is made to <FIG> which shows a third version of the pump assembly in which, while similar to the first and second versions, the outer chamber <NUM> is larger than chamber <NUM> intermediately inwardly therefrom. Rather than providing a one-way valve mechanism for one way flow inwardly from the reservoir to the chamber <NUM>, such as the inner disc <NUM> in an inner chamber in the case of <FIG>, a one-way valve <NUM> is provided in an inlet port <NUM> to the chamber <NUM>. Valve <NUM> has a stem <NUM> which carries an inner valve disc <NUM> which extends radially outwardly from the stem <NUM> to engage the side wall of the chamber <NUM>. The valve disc <NUM> has a resilient outer perimeter which is directed outwardly and engages the chamber <NUM> to prevent fluid flow therepast inwardly yet deflects radially inwardly to prevent fluid flow outwardly therepast. Similar such one-way valves could be used in replacement of the inner disc <NUM> in the embodiments of <FIG>.

Reference is made to <FIG> which illustrates a first alternate form of a piston <NUM> adapted for substitution of the piston <NUM> in the embodiment of <FIG>. Piston <NUM> as shown in <FIG> is identical to that shown in <FIG>, however, includes a one-way valve <NUM> provided on the outer disc <NUM> and adapted to provide for fluid flow inwardly through the outer disc <NUM> and to prevent fluid flow outwardly. In this regard, the disc <NUM> is provided with a center opening <NUM> therethrough and a pair of openings <NUM> on either side of the center opening. A valve member <NUM> has a stem with an arrow-like head <NUM> which is adapted to pass through the center opening and secure the valve member therein against removal. The valve member includes an inner flexible disc member <NUM> which inherently assumes a flat condition to overlie and close the openings <NUM> and <NUM>, however, which is resiliently deflectable so as to deflect to the positions illustrated in dashed lines in <FIG> so as to permit air flow inwardly through the opening as when, in an extension stroke, a pressure differential is created as a result of creating a vacuum inside the outer chamber <NUM>. Thus, on an extension stroke, atmospheric air may flow into the outer chamber <NUM> through the one-way valve <NUM> provided in the outer disc <NUM>. However, on a retraction stroke on moving of the piston <NUM> inwardly, the one-way valve <NUM> prevents fluid flow outwardly through the one-way valve.

Reference is made to <FIG> which shows a second alternate form of a piston <NUM> for use in the embodiment of the piston assembly shown in <FIG>. The second alternative shown in <FIG> is identical to that shown in <FIG> with the exception that the outer disc <NUM> is provided with an inwardly directed resilient inner periphery <NUM> which is adapted to engage the wall <NUM> of the outer chamber <NUM> so as to prevent fluid flow outwardly therepast yet which is adapted to deflect radially inwardly so as to permit atmospheric air to flow past the outer disc <NUM> on the piston <NUM> moving outwardly. The second alternative piston <NUM> of <FIG> also includes a one-way valve <NUM> provided internally within the passageway <NUM> between the inlet <NUM> and the screen <NUM>. This valve <NUM> has an inner securing disc <NUM> frictionally received in the passageway <NUM> against movement. A stem <NUM> extends axially from the disc <NUM> and carries a resilient outwardly directed flexible disc <NUM>. The securing disc has openings <NUM> therethrough permitting passage. The flexible sealing disc <NUM> has a resilient outer periphery which is adapted to engage the inner surface of the passageway <NUM> to prevent fluid flow inwardly therepast yet is adapted to deflect radially inwardly so as to permit fluid flow outwardly through the passageway <NUM>. In use of a piston as illustrated in <FIG>, the one-way valve <NUM> inside the stem <NUM> substantially prevents any fluid flow back into the outer chamber <NUM> in an extension stroke such that effectively all air to be drawn into the outer chamber <NUM> in the extension stroke must be drawn past the deflecting outer periphery of the outer disc <NUM>. As a further embodiment, the interior one-way valve <NUM> is not provided and, thus, in the extension stroke, there may be draw back of air and foam through the screen <NUM> as well as drawing of air into the chamber <NUM> by reason of deflection of the resilient periphery <NUM> of the outer disc <NUM>.

Reference is now made to <FIG> which shows an eleventh embodiment of a pump assembly. The pump assembly <NUM> in <FIG> is identical to the pump assembly of <FIG> with the exception that the piston <NUM> has been modified so as to provide the outer disc <NUM> with an annular resilient peripheral flange. The resilient flange includes not only an inwardly and outwardly directed outer arm <NUM> but also a resilient radially inwardly and inwardly directed inner arm <NUM>. The body <NUM> in <FIG> is identical to that in <FIG> with the exception that an annular channel <NUM> extends inwardly into the shoulder <NUM> of the outer chamber <NUM> which annular chamber <NUM> has a common outer wall <NUM> with the remainder of the chamber <NUM> and provides a new outwardly directed inner wall <NUM>.

The outer arm <NUM> is adapted to engage the cylindrical wall <NUM> of the outer chamber <NUM> to prevent fluid flow outwardly therepast.

While the inner arm <NUM> engages on the cylindrical inner wall <NUM>, the inner arm prevents flow of fluid, notably atmospheric air, past the outer disc <NUM> inwardly to between the outer disc <NUM> and the intermediate disc <NUM>. Thus, in a withdrawal stroke, on the piston <NUM> moving from the retracted position illustrated in <FIG> to an intermediate position in which the inner arm <NUM> is axially outward from the shoulder <NUM> such that the inner arm <NUM> does not engage the inner wall <NUM> or the shoulder <NUM>, then the flow of air inwardly past the outer disc <NUM> is prevented. However, in an extraction stroke, once the inner arm <NUM> is outwardly of the shoulder <NUM> and thus out of the annular channel <NUM>, atmospheric air may be drawn inwardly past the outer disc <NUM> by deflection of arm <NUM>. It is to be appreciated, therefore, that from a retracted position illustrated in <FIG> moving the piston outwardly initially while the inner arm <NUM> is within the annular channel <NUM>, there is drawback of fluid including air and liquid from the passageway <NUM> as can be advantageous as to prevent dripping of liquid and foam out the outlet <NUM>. However, on further outward movement of the piston <NUM> with the inner arm <NUM> outwardly of the annular channel <NUM>, the suction produced between the outer disc <NUM> and the intermediate disc <NUM> may also draw air inwardly past the outer arm <NUM> and, as a result, atmospheric air may flow between the outer disc <NUM> and the intermediate disc <NUM> either outwardly past the outer disc <NUM> or through the passageway <NUM> with the relative proportion of the flow having regard to the relative resistance of flow through each of the two pathways. It is to be appreciated, that while the inner arm <NUM> is within the annular channel <NUM> that there is drawback only through the passageway <NUM> and that once the inner arm <NUM> clears the annular channel <NUM> that there may be effectively only flow inwardly past the outer periphery of the outer disc <NUM>. A bifocated inner disc as illustrated in <FIG> may be adapted for use in other of the embodiments illustrated.

Reference is made to <FIG> which shows a fourth version of a pump. The pump assembly illustrated in <FIG> can be considered to be similar to that in <FIG>, however, with the intermediate disc <NUM> removed, the stem <NUM> provided with a cylindrical constant cross-sectional area between the inner disc <NUM> and the outer disc <NUM> and the intermediate chamber <NUM> reduced in diameter to a diameter close to that of the stem <NUM> between the inner disc <NUM> and the outer disc <NUM> so as to effectively prevent any substantial fluid flow therebetween. A one-way valve <NUM> is provided between the inner and outer chambers. Two channels <NUM> and a center opening <NUM> are provided between the inner chamber <NUM> and the outer chamber <NUM> having inlets in the outer shoulder <NUM> of the inner chamber <NUM> and an outlet in the inner shoulder <NUM> of the outer chamber <NUM>. A one-way valve member <NUM> is provided which prevents fluid flow inwardly through the channels <NUM> and opening <NUM> yet permits fluid flow outwardly through the channels <NUM>. The one-way valve member <NUM> has a central stem passing through the central opening <NUM> carrying a flexible disc outwardly of the channels <NUM> and an arrowhead retained inwardly. The channels <NUM> and the one-way valve member <NUM> therefore provide a similar function to the intermediate disc <NUM> of the embodiment of <FIG> or the intermediate flange <NUM> of the embodiment of <FIG>. <FIG> is also modified to show replacement of the screen <NUM> by a nozzle member <NUM> disposed proximate the outlet <NUM> to at least partially atomize liquid when liquid and air pass therethrough simultaneously.

In <FIG>, the piston <NUM> is slightly modified over that illustrated in <FIG> in respect of the inner disc <NUM> which has had its outer periphery reduced in thickness so as to show a configuration in which the inner disc <NUM> is sufficiently resilient that the inner disc <NUM> may pass inwardly through the intermediate chamber <NUM> such that the piston may be formed as a unitary element from plastic as by injection moulded and inserted through the outer chamber <NUM>. This, for example, avoids the need of the piston to be made into portions as illustrated, for example, in the embodiment of <FIG>.

In operation of the pump illustrated in <FIG>, in the piston <NUM> moving from the retracted position to the extended position, a volume of liquid equal to a first volume is displaced in an inward direction past the intermediate disc <NUM> to between the intermediate disc <NUM> and the outer disc <NUM> and a volume equal to a second volume which is greater than the first volume and comprises both liquid and air is drawn in between the intermediate disc <NUM> and the outer disc <NUM>. In the piston <NUM> moving from the extended position to the retracted position, a volume of liquid from the reservoir equal in volume to the first volume is displaced in an outward direction past the inner disc <NUM> to between the inner disc <NUM> and the intermediate disc <NUM> and a volume equal in volume to the second volume and comprising both liquid and air is displaced from between the intermediate disc <NUM> and the outer disc <NUM> out of the outlet <NUM>. In the piston <NUM> moving from the retracted position to the extended position, the volume equal to the second volume which was drawn in between the intermediate disc <NUM> and the outer disc <NUM> comprises the first volume displaced in the outward direction past the intermediate disc plus a third volume comprising air from atmosphere and may include as a fourth volume liquid drawn back via the outlet from the passageway.

In respect of an embodiment using a piston <NUM> as illustrated in <FIG> in a body as illustrated in <FIG> and including the interior one-way valve <NUM> within the passageway <NUM>, then on the piston <NUM> moving from the retracted position to the extended position, the volume equal to the second volume which was drawn into between the intermediate disc <NUM> and the outer disc <NUM> comprises the first volume consisting of fluid displaced in the outward direction past the intermediate disc <NUM> and a third volume comprising air from the atmosphere drawn inwardly past the outer disc <NUM>. Insofar as the piston as illustrated in <FIG> is used in a body as in <FIG> but without one-way valve <NUM>, then the second volume would comprise the first volume displaced in the outward direction past the intermediate disc <NUM> and a third volume comprising air from the atmosphere which may be drawn through the passageway <NUM> and/or outwardly past the outer disc <NUM>. The same would be true in respect of the embodiment illustrated in <FIG>. Insofar as there is drawback of liquid through the outlet <NUM>, then the second volume would also include as a fourth volume liquid drawn back through the passageway <NUM>.

The embodiment of <FIG> as well as <FIG> and <FIG> and <FIG> and <FIG> illustrate configurations in which the relative amounts of liquid and air may be dispensed can be varied. The embodiment of <FIG> effectively illustrate modification by varying the axial extent of the inner chamber <NUM>. The body <NUM> may be manufactured by injection moulding with the mould cavity forming the body <NUM> to provide for variable axial extent of the inner chamber <NUM>. In this manner, by using substantially the same mould, bodies and therefore pumps, may be provided which provide for dispensing of different volumes of liquid merely by varying the axial length of the inner chamber <NUM>.

A principal operation of pumps in accordance with many of the described embodiments is that the volume dispensed past the outer disc is greater than the volume dispensed past the intermediate disc. Thus, for example, in the embodiment such as in <FIG>, with the volume dispensed past the outer disc <NUM> being greater than the volume dispensed past the intermediate disc <NUM>, this allows for air to be drawn into the pump assembly and, subsequently, dispensed. Where the inner, intermediate and outer discs all remain in engagement with their respective chambers throughout the retraction and extension strokes, then it is preferred that the difference in area between the outer chamber and the intermediate chamber is greater than the difference in area between the inner chamber and the intermediate chamber. This relation may be seen, for example, in the embodiment of <FIG>.

Reference is made to <FIG> which shows a thirteenth embodiment of a pump assembly. The pump assembly illustrated in <FIG> can be considered to be similar to that in <FIG>, however, with the intermediate disc <NUM> removed, the stem having a cylindrical constant cross-sectional area between the inner disc <NUM> and the outer disc <NUM>, the intermediate chamber is effectively reduced in diameter to a diameter which will engage the stem between the inner disc <NUM> and the outer disc <NUM> and effectively prevent a substantial fluid flow therebetween. A channel is, however, provided between the inner chamber <NUM> and the outer chamber <NUM> having an inlet in the outer shoulder of the inner chamber and an outlet in the inner shoulder of the outer chamber. A one-way valve is provided in this channel which prevents fluid flow inwardly through the channel yet permits fluid flow outwardly through the channel. The channel and the one-way valve therefore provide a similar function to the intermediate disc <NUM> of the embodiment of <FIG> or the intermediate flange of the embodiment of <FIG> is also modified to show a replacement of the screen <NUM> by a nozzle member <NUM> disposed proximate the outlet <NUM> to at least partially atomize liquid when liquid and air pass therethrough simultaneously.

<FIG> is an inventive modification of the embodiment illustrated in <FIG> so as to provide at the inner end of the piston <NUM> rather than the air pump disc <NUM> which slides within the air chamber-forming member <NUM>, a flexible inner bellows/spring member <NUM> which extends rearwardly as an integral portion of the piston <NUM> to engage the rear wall <NUM> of the element <NUM>. The inner bellow member <NUM> as illustrated in <FIG> is compressed such that the inner bellows member <NUM> always urges the disc <NUM> forwardly towards engagement with the shoulder <NUM>. With inward movement of the piston <NUM> in use, the inner bellows member <NUM> further resiliently deflects and, in this regard, acts as a spring to bias the piston <NUM> outwardly.

In addition, as the piston <NUM> is moved rearwardly, the internal volume in the air chamber <NUM> inside the inner bellows member <NUM> decreases such that the inner bellows member <NUM> draws air in and expels air out during use.

The inner bellows member <NUM> has the advantage of serving both as a pump and an internal spring to bias the piston <NUM>, however, it may in other embodiments serve merely one or the other or both of these functions and, as well, may be adapted for pumping air, or fluid or a mixture of air and fluid.

<FIG> illustrates a further inventive modification of <FIG> over that of <FIG> such that the piston outer disc <NUM> of <FIG> is also replaced by a second bellows member <NUM> which will not only draw in and dispense air/liquid but also acts as a spring to bias the piston <NUM> outwardly.

Reference is made to <FIG> which illustrates a further embodiment of a pump in accordance with the present invention and which an inner bellows member <NUM> is provided at the inner end of an inner core <NUM> of a pump in a similar manner to that shown in <FIG>. However, in <FIG>, the pump mechanism is a gravity feed metering pump for movement and dispensing of fluid from a reservoir past disc <NUM> as in a manner disclosed in <CIT>. It is to be appreciated that the inner bellows <NUM> in <FIG> has replaced a piston pump similar to that illustrated in <FIG>. As well, it is to be appreciated than an outer bellows <NUM> could be provided in replacement of the sealing flange <NUM> in <FIG>.

<FIG> is a further inventive embodiment in which an outer bellows <NUM> is provided which forms the sole air chamber for drawing air in via outlet <NUM> and dispensing it outwardly through outlet <NUM>. The bellows chamber <NUM> receives liquid from the reservoir from a stepped cylinder liquid pump including discs <NUM> and <NUM>. Both air and liquid are dispensed via port <NUM> to passageway <NUM> and out through the foam generators <NUM>, <NUM> and <NUM>.

<FIG> illustrates a modified inventive form of the embodiment of <FIG> including an outer bellows <NUM> which is adapted to serve merely as a spring since the bellows <NUM> has an air vent opening <NUM> to relatively, freely permit passage of air inwardly and outwardly therefrom. While an accordion-like outer bellows member <NUM> is shown in <FIG>, a bellows member such as in <FIG> could also be used with an air vent.

Disc <NUM> is modified over that of <FIG> so as to prevent fluid flow outwardly therepast. An inlet <NUM> is provided through the side wall of the stem <NUM> of the piston between the discs <NUM> and <NUM> directing fluid between discs <NUM> and <NUM> outwardly into passageway <NUM>. The dispenser of <FIG> merely dispenses liquid.

In each of the inventive embodiments illustrated in <FIG>, each of the inner bellows <NUM> and outer bellows <NUM> provide a bellows chamber inside a flexible and collapsible side wall which bellows chamber increases in volume with movement of the piston <NUM> towards the extended position and reduces with volume with movement of the piston <NUM> towards a retracted position. Each of the bellows is provided to act as a resiliently collapsible and expandable pump so as to draw fluid inwardly into the bellows chamber and dispense fluid outwardly from the bellows chamber.

In the preferred embodiments illustrated, the resilient bellows member is formed integrally with a component of the piston having a central axially extending hollow stem with a bellows formed as an extension of the hollow stem and open to the hollow stem.

Each of the bellows members <NUM> and <NUM> illustrated are formed as the end of a tubular member. In each of the embodiments in <FIG>, the piston <NUM> is formed from a number of elements secured together as a unit and including as two principal elements an outer casing <NUM> and an inner core <NUM>. The inner core <NUM> carries a hollow support tube <NUM> from whose inner end the inner bellows <NUM> extends inwardly to its inner end <NUM> which engages in a sealed manner the end wall <NUM> of the air chamber-forming member <NUM>. The outer casing <NUM> includes a small tube portion <NUM> at its outer end and a large tube portion <NUM> open at an inner end from which the outer bellows <NUM> extends inwardly to its inner end <NUM> which engages in a sealed manner an outer side of the flange portion <NUM>.

In both the embodiments of <FIG>, the inner bellows member <NUM> is formed as an inner extension of a portion of the piston <NUM> open to the central internal passageway <NUM> through the hollow stem <NUM>.

In each of the embodiments of <FIG>, at least one annular chamber is formed annularly about the stem <NUM> between the piston <NUM> and the piston-chamber forming member <NUM> such that with reciprocal sliding of the piston <NUM> between the retracted and the extended position, there is controlled movement of liquid from the reservoir into the annular chamber and for dispensing of liquid in the annular chamber to the outlet with or without the simultaneous dispensing of air.

Each of the bellows <NUM> and <NUM> is formed from a resilient material which will have an inherent tendency to assume an expanded configuration. Plastic material such as polyethylene and polypropylene and copolymers provide for adequate resiliency. The bellows effectively forms an axially compressible, resilient tube section, the outer wall of which forms the plurality of stepped annular portions. The resiliency of the wall provides an inherent bias like a compression spring to return the wall to an extended configuration. The side wall effectively is pleated and adapted to collapse the side wall longitudinally. The side wall illustrated in <FIG> is roughly conical increasing in diameter stepwise inwardly. In <FIG>, the bellows member <NUM> is shown as having an accordion-like side wall of relatively constant diameter. Alternatively, the side wall may be formed with spiral grooves and spiral lands therebetween rather than merely annular lands.

Reference is made to <FIG> which illustrates a <NUM>th embodiment which may be considered a modification of the embodiment of <FIG> to replace the bellows <NUM> by a spring <NUM>. As seen in <FIG>, the spring <NUM> in integrally formed with a spring chamber-forming member <NUM> which is otherwise the same as the air chamber-forming member <NUM> described with reference to <FIG> and <FIG>. Like the bellows <NUM> of <FIG>, the spring <NUM> is resiliently compressible and biases the piston <NUM> outwardly to an extended position. As contrasted with the embodiments of <FIG> and <FIG>, the piston <NUM> has its passageway <NUM> closed at an inner end at <NUM>. The hollow support tube <NUM> of the inner core <NUM> of the piston <NUM> receives a neck tube <NUM> of the spring <NUM> fixedly secured therein to couple the inner end of the piston <NUM> to the spring <NUM>. The pump of <FIG> will effectively operate in a similar manner to the pump illustrated in <FIG>, however, with the spring <NUM> biasing the piston <NUM> outwardly to an extended position and becoming compressed on movement of the pump inwardly towards a retracted position.

Reference is made to <FIG> illustrating a <NUM>th embodiment. The pump assembly <NUM> in <FIG> has a piston chamber-forming body <NUM> and piston <NUM>. The body <NUM> has an outer tubular portion <NUM> connected by a first flange <NUM> to an inner end of an intermediate tubular portion <NUM> whose outer end is connected by a second flange <NUM> to an inner tubular portion <NUM>. The outer chamber <NUM> is formed radially inwardly of the outer tubular portion <NUM> having a side wall <NUM> thereabout. The intermediate chamber <NUM> is formed radially inwardly of the inner tubular portion <NUM> within the side wall <NUM>. The inner chamber <NUM> is formed radially inwardly of the intermediate tubular portion <NUM> with a side wall <NUM> thereabout. An outlet opening of the inner chamber <NUM> opens into an inlet end of the intermediate chamber <NUM>. An outlet opening of the intermediate chamber opens <NUM> into an inlet end of the outer chamber <NUM>.

The piston <NUM> is formed from an outer casing <NUM>, an inner core <NUM> and a foam producing element <NUM>. The foam producing element <NUM> is preferably a cylindrical disc of porous materials such as open pore foamed plastic. The foam producing element is retained in a compartment <NUM> formed in the outer end of the outer casing <NUM> outwardly of the outer end of the inner core <NUM> which is fixedly secured to the outer end of the outer casing <NUM> as shown. The outer casing <NUM> carries the outer disc <NUM> for engagement within the outer chamber <NUM> and its side wall <NUM>. The outer tubular portion <NUM> includes a cylindrical extension <NUM> outwardly from the outer chamber <NUM> adapted to be engaged by a locating flange <NUM> carried by the outer casing <NUM> of the piston <NUM> to assist in coaxially locating the piston <NUM> in the body <NUM>. The piston <NUM> has an elongate stem <NUM> which carries an inner flexing disc <NUM> at an innermost end and an intermediate flexing disc <NUM>. The inner flexing disc <NUM> is coaxially received within the inner chamber <NUM>. The intermediate flexing disc <NUM> is coaxially disposed within the intermediate chamber <NUM>. As seen in <FIG> and <FIG>, the piston <NUM> advantageously carries a plurality of circumferentially spaced locating flanges only one of which is shown as <NUM> between the inner disc <NUM> and the intermediate disc <NUM> for engagement with the chamber wall <NUM> of the intermediate chamber <NUM> to assist in coaxially locating the piston <NUM> in the body <NUM>.

An outermost portion of the stem <NUM> is hollow with a central passageway <NUM> extending from an outlet <NUM> at the outermost end of the stem <NUM> centrally through the stem <NUM> to a closed inner end <NUM>. Radially extending inlets <NUM> extends radially through the stem into the passageway <NUM>, with the inlets <NUM> being provided on the stem in between the outer disc <NUM> and the intermediate disc <NUM>.

The piston <NUM> carries an engagement flange <NUM> complementary with an engagement slot <NUM> together provided for engagement as by an activating device in order to move the piston inwardly and outwardly relative to the body <NUM>. An innermost portion of the stem <NUM> is also hollow with a central bore <NUM> closed at an outer end at <NUM>. A spring assembly <NUM> is coupled between the body <NUM> and the piston <NUM> to bias the piston <NUM> outwardly to an extended position. Spring assembly <NUM> includes a spring <NUM> disposed within a hollow tubular spring housing <NUM>. The spring housing <NUM> has an outer end <NUM> secured in a snap-fit relation onto the inner end of the outer tubular portion <NUM> of the body <NUM> about the first flange <NUM>. The spring housing <NUM> extends outwardly as a generally cylindrical but marginally frustoconical, inwardly tapering wall <NUM> to an inner end providing a radially inwardly extending flange <NUM> supporting the inner end <NUM> of the spring <NUM>. The spring <NUM> extends from its inner end <NUM> outwardly to an outer end formed as a tubular neck <NUM> which is securely, fixedly engaged and received within the bore <NUM> of the piston <NUM>. Openings <NUM> are provided through the side walls of the spring housing <NUM> provide for communication from the interior of a container to the inlet opening of the inner chamber <NUM>. Strictly speaking, such openings <NUM> are not required as in the preferred embodiment, the interior of the container is also in communication with the inlet opening of the inner chamber <NUM> through the central opening <NUM> in the flange <NUM> of the spring housing <NUM> and downwardly through side openings <NUM> in the spring <NUM>. However, the openings <NUM> provide for fluid in a container at a height below the opening <NUM> in the flange <NUM> of the spring housing <NUM> to gain access to the inlet opening to the inner chamber and, thus, be dispensed.

The spring member <NUM> has a side wall <NUM> which extends inwardly from the flange of the spring housing <NUM> to the tubular neck <NUM> of the spring <NUM>. As marked on <FIG>, the side wall <NUM> in the preferred embodiment has a conical portion generally indicated as <NUM> which is frustoconical terminating at a dome portion indicated as <NUM> over which the side wall <NUM> curves from the end of the conical portion <NUM> to extend substantially normal to an axis <NUM> coaxially of the piston <NUM> where the side wall <NUM> merges into the tubular neck <NUM>. The side wall <NUM> of the spring <NUM> has two openings <NUM> diametrically opposed from each other extending from the dome portion <NUM> to the flange <NUM>. The side openings <NUM> may be conceptually considered to have been formed as by considering providing a member having the outer side wall as seen in <FIG> completely circumferentially about the axis <NUM> as a solid of rotation about the axis and then cutting away portions of the side wall <NUM> in planes on either side of the axis perpendicular to the cross-section shown in <FIG> along the lines indicated in <FIG> as comprising the openings <NUM>.

The pictorial views of <FIG>, <FIG> best show the side wall <NUM> of the spring <NUM> with the openings <NUM> through the side wall <NUM> from an exterior surface <NUM> of the side wall <NUM> into an interior of the spring. <FIG> illustrate enlarged cross-sectional views of the spring assembly <NUM> in an unbiased extended position as, for example, illustrated in <FIG>, <FIG> and in the same positions as are shown in <FIG>, respectively.

In use of the pump of the embodiment of <FIG>, the pump is moved from the extended position of <FIG> to the retracted position of <FIG>. Axial inward movement of the piston <NUM> relative to the body <NUM> compresses the spring <NUM>. The spring <NUM> has an inherent bias to assume its uncompressed position shown, for example, in <FIG> and, thus, will apply forces to the piston urging the piston <NUM> towards the fully extended position. <FIG>, <FIG>, <FIG> and <FIG> illustrate the spring <NUM> in a fully retracted compressed condition. As seen, the conical portion <NUM> of the walls <NUM>, at least in a mid-section of the conical portion, have been deflected radially outwardly. The dome portion <NUM> has been deflected to increase the radius of the dome as, for example, flattening the upper central-most portion of the dome portion <NUM>. With the embodiment illustrated, further compression of the spring <NUM> is prevented by a stop mechanism of the outer end of the inner tubular portion <NUM> engaging the outer casing <NUM> of the piston <NUM>. If further compression of the spring member <NUM> may be permitted, continued outward deflection of the conical portion <NUM> of the side wall <NUM> would occur and a central portion of the dome portion could be moved such that its outer surface about the tubular neck <NUM> may become successively less convex, then flat and, subsequently, concave with the portion of the side wall about the neck <NUM> to extend inwardly past radially outer portions of the side wall such that the side wall deflects to double back on itself. Such an inversion of the dome portion <NUM> from having a convex outer surface to having a concave outer surface can be advantageous for providing biased resiliency to the spring <NUM>.

As seen in the Figures, the spring <NUM> when in the unbiased extended position has a greatest diameter at its first end and a least diameter at its second end. The two openings <NUM> through the side wall <NUM> are diametrically opposite each other and symmetrical relative to the axis <NUM> circumferentially and longitudinally of the axis <NUM>. As well, each opening <NUM> is symmetrical about a notional medial plane passing centrally through the opening <NUM> and including the axis <NUM>. Each opening also lies in the intersection with the side wall <NUM> of a notional flat plane normal to such medial plane. Each opening increases with circumferential extent with distance from the second end. The side wall <NUM> has a substantially constant thickness, however, the side wall <NUM> preferably should have a thickness which is substantially constant or which varies gradually by a gradient over any two adjacent points on its surface of no more than between <NUM> percent and <NUM> percent.

Providing the spring assembly <NUM> to be a separate element from the other elements of the pump is advantageous insofar as the spring <NUM>, to provide desired resilient characteristics, may be desired to be made from a different plastic than the other elements of the pump. However, the description is not limited to providing the spring assembly <NUM> as a separate element. The spring <NUM> may be formed as an integral rearward extension of the piston <NUM>, for example, in a manner that the bellows <NUM> forms an extension of the piston <NUM> in <FIG> albeit with the internal passageway <NUM> requiring to be closed rearward from the inlets <NUM>. If the spring <NUM> is to be formed integrally with the piston <NUM> then, advantageously, the spring housing <NUM> may be formed as an integral part of the body <NUM> as a rearward, substantially cylindrical extension thereof having, for example, a similar flange <NUM> and central opening <NUM> through the flange <NUM> through which the inner core <NUM> of a piston <NUM> including the spring <NUM> may be inserted during assembly.

In accordance with the present description, a similar spring member may be provided, however, without the side openings <NUM> and therefore formed, for example, to have a side wall <NUM> which extends <NUM>° about its central axis as a solid of revolution about the axis <NUM>. Providing the openings <NUM> through the side wall <NUM> is advantageous, however, for a number of reasons. Firstly, it at least partially eliminates the difficulty of a compartment formed inside the spring housing <NUM> below the spring <NUM> acting as a displacement pump and tending to draw and dispense fluid inwardly and outwardly through the openings <NUM>. This difficulty could, however, be simply overcome by increasing the size and number of openings <NUM>. More significantly, providing the side openings <NUM> assists in selecting the characteristics of the spring <NUM> as to the relative thickness of the side wall and the spring forces that are generated with distance of deflection from the unbiased extended position of the spring <NUM>. The circumferential extent of the openings <NUM> at any position along the axial length of the spring <NUM> and the relative location of the side openings <NUM> axially relative to the spring can affect the strength and deflections of the spring.

As contrasted with the use of a bellows such as the bellows <NUM> in <FIG> as a spring member, the spring <NUM> provides for relatively smooth biasing resistance forces as contrasted with a pleated bellows which tends to provide stepped changes in the resistance as the bellows become folded or bent about each of its pleats or folds. With any particular thickness of the side wall <NUM> of the spring <NUM>, the relative size and location of the side openings <NUM> can be changed as would be apparent to a person skilled in the art at the least, on a trial and error basis, towards developing suitable forces with distance of compression as well as for the extent of deflection.

The preferred spring assembly <NUM> is adapted for coupling at an inner end of both the body <NUM> and the piston <NUM>. The spring <NUM> is not, however, limited to such use and may be used for a variety of other uses as a spring other than merely in a pump.

Reference is made to <FIG> which illustrates a spring member <NUM> similar to that illustrated in <FIG>, however, provided as a separate member without the spring housing <NUM>. Advantageously, as seen in <FIG>, at the inner end of the spring, the side wall includes a circumferential ring <NUM> which assists in retaining the diametrically opposed side portions <NUM> and <NUM> of the side wall <NUM> together.

Reference is made to <FIG> which illustrate a number of other versions of a spring <NUM>. The embodiments of <FIG> are each embodiments in which no openings are provided through the side walls <NUM> of the springs <NUM>. The embodiments illustrated in <FIG> each have two or more openings <NUM> through the side walls <NUM> uniformly spaced circumferentially about a center axis through the spring <NUM>.

In the embodiments of <FIG>, at the closed end of the spring <NUM>, an engagement socket <NUM> is provided with extends coaxially into the interior of the spring as contrasted with the embodiments of <FIG> in which there is a coaxial neck <NUM> which extends outwardly from the spring <NUM>.

The embodiment of <FIG> illustrate an arrangement in which the side walls <NUM> are cylindrical and the end wall <NUM> is circular in a plane extending radially to the axis <NUM>. In the embodiment of <FIG>, the side walls <NUM> are conical. In the embodiment of <FIG>, the side walls <NUM> are generally dome shaped, approaching that of a semi-sphere.

The embodiment of <FIG> have a flange <NUM> extending radially outwardly from the side wall <NUM> and with the side openings <NUM> extending axially inwardly through the flange <NUM> with the portions of the flange radially outwardly of the side wall <NUM> providing a continuous annular rim to keep the spaced segments <NUM>, <NUM> and <NUM> of the side wall <NUM> together.

The spring members <NUM> may preferably be disposed within a complementary spring housing exemplified by the spring housing <NUM> of <FIG>. The spring housing can be of assistance in ensuring that the spring member <NUM> remains substantially coaxially disposed in collapsing, or at least does not deviate unduly from collapsing coaxially by reason of inside surfaces of a wall of the spring housing <NUM> becoming engaged with outside surfaces of the wall of the spring member <NUM>. The spring housing <NUM> may preferably be provided with an interior surface complementary to the shape and nature of the spring <NUM> received therein to permit and accommodate desired deflection yet to prevent undesired deflection. For example, in the context of the spring <NUM> shown in <FIG> with a cylindrical wall, the housing may also be a cylindrical wall spaced radially outwardly from the spring <NUM> but not to distant therefrom so as, for example, to enhance inversion of the spring <NUM> with the end wall to become domed inwardly in a concave manner and, subsequently, be moved radially inwardly down inside the spring with the side walls <NUM> of the spring doubling over on themselves.

The relative thickness of the side wall of the spring <NUM> is shown in the preferred embodiments to be relatively constant, however, it is to be appreciated that the thickness of the side wall, that is, measured from its inside surface to its outside surface may be varied as may be desirable to provide for different resiliencies and stiffness of the side wall at varying portions. Transitions in the thickness of the side wall preferably are gradual and not stepwise. The thickness of the side wall may vary in the axial direction of the spring.

Preferred materials of construction of the spring <NUM> are elastomeric and plastic materials which can be easily manipulated by injection moulding yet will have an inherent resiliency suitable to serve as a spring and, as well, a longevity in terms of its resiliency over repeated deflection for sufficient time and number of cycles as appropriate to the use to which the spring is to be placed. The spring member <NUM> is particularly adapted for use as in pumps for dispensing liquids with the entirety of the pump and container to be disposed when the container is emptied of fluid.

Claim 1:
A pump (<NUM>) for dispensing a liquid from a reservoir (<NUM>) comprising:
a piston-chamber forming member (<NUM>),
a piston forming element (<NUM>) received in the piston chamber-forming member (<NUM>) axially slidable inwardly and outwardly therein between an inward retracted position and an outward extended position,
said piston forming element (<NUM>) having a central axially extending hollow stem (<NUM>) having a central passageway (<NUM>) with an inner end and having an outlet (<NUM>) proximate an outer end extending out of the piston-chamber forming member (<NUM>) and from which the liquid is dispensed,
at least one annular chamber (<NUM>, <NUM>) formed annularly about the stem between the piston forming element (<NUM>) and the piston-chamber forming member (<NUM>) providing for controlled movement of the liquid from the reservoir (<NUM>) into the annular chamber (<NUM>, <NUM>) and for dispensing of the liquid in the annular chamber (<NUM>, <NUM>) to the outlet (<NUM>) with reciprocal sliding of the piston forming element (<NUM>) between the retracted position and the extended position,
characterized by:
said piston forming element (<NUM>) having a bellows member (<NUM>), the bellows member (<NUM>) extending inwardly from the stem (<NUM>) to form with the piston-chamber forming-member (<NUM>) a bellows chamber (<NUM>) open to the inner end of the passageway (<NUM>),
the bellows member (<NUM>) being collapsible to increase and decrease a volume of the bellows chamber (<NUM>) with reciprocal sliding of the piston forming element (<NUM>) between the retracted position and the extended position to draw the fluid through the outlet (<NUM>) via the passageway (<NUM>) into the bellows chamber (<NUM>) and to expel the fluid in the bellows chamber (<NUM>) via the passageway (<NUM>) out the outlet (<NUM>).