WO2000042890A1

WO2000042890A1 - A beverage maker

Info

Publication number: WO2000042890A1
Application number: PCT/GB2000/000113
Authority: WO
Inventors: Thomas Robinson
Original assignee: Windmill Holdings Ltd
Current assignee: Windmill Holdings Ltd
Priority date: 1999-01-19
Filing date: 2000-01-18
Publication date: 2000-07-27
Anticipated expiration: 2001-07-19
Also published as: GB9901152D0

Abstract

The separator piston disc (18) which is driven towards the base (15) of the jug of a coffee maker comprises a major planar portion (19) and a flared circumferential portion (21) which presents an annular concave surface to the base (15) of the jug. The major planar portion (19) and the flared peripheral portion (21) of the disc (18) are formed as a one-piece mesh member of plastics material which has a frayed peripheral edge (22).

Description

A BEVERAGE MAKER

This invention relates to a beverage maker which includes a chamber having a closed end, a pouring spout spaced from the closed end and a separator piston disc which is provided with a seal around its periphery and which is slidable within the chamber between the pouring spout and the closed end, the separator piston disc being permeable to water and the beverage whilst being impenetrable to solid raw material from which the beverage is made and being adapted to be driven towards the closed end of the chamber, the seal being operably co-operative with the sides of the chamber so as to seal against passage of the raw material between the disc and the sides of the chamber from below the disc, the arrangement being such that the solid raw material is placed in the chamber between the closed end and the separator piston disc and the chamber is filled with hot water which interacts with raw material to form the beverage, the separator piston disc being driven towards the closed end to separate the residue of the raw material from the resultant beverage. Such a beverage maker is referred in the rest of this description as "a beverage maker of the kind referred to". More particularly, although not exclusively, this invention relates to a coffee maker.

Occasionally the piston of such a coffee maker locks in mid-stroke whilst it is being driven down towards the closed end of the chamber. This is due to a concentration of coffee grounds building up under the piston ring seal and acting as a wedge between the piston ring seal and the wall along which it slides, to impede further downwards movement of the piston. This is acknowledged by purveyors of conventional coffee makers of this type who provide instructions for dealing with this problem, those instructions being for the user to stop urging the piston down, to lift it slightly to enable release of the build up of coffee grounds and then to continue pushing the piston down.

Our International Patent Publication No.WO 99/58034 describes, claims and illustrates a coffee maker comprising an open-topped vessel having a base and substantially straight sides upstanding from the periphery of the base and forming a pouring spout, a lid for fitting to the open-top whereby to enclose the interior of the vessel, a separator piston disc having a plan form profile similar to that of the base and formed so as to be permeable to liquid but impenetrable to coffee grains, manually operable means for driving the disc downwards within the vessel to separate the residue of the coffee grains from the liquid, the disc being provided with a seal around its periphery, the seal being operably cooperative with the sides of the vessel so as to seal against passage of coffee grains between the disc and the sides of the vessel from below the disc to part of the interior of the vessel above the disc, wherein the manually operable means for driving the disc downwards within the vessel comprise a screw which depends from the lid by which it is supported for rotation about its axis relative to the lid, a manually engagable component which is fixed to the upper end of the screw and which is accessible from above the lid so that it can be taken by hand and turned whereby to turn the screw about its axis, and the disc being formed as a nut which is in screw threaded engagement with the screw so that it rises or descends within the vessel with rotation of the screw, there being means operable to hold the disc against rotation with rotation of the screw.

The problem of build up of coffee grounds does not arise if the seal is a circumferentially continuous ring which is a lip seal as proposed by US- A-2,935,928 becacuse the lip seal wipes the inner surface of the sides of the vessel as the disc is driven downwards. However, if the vessel is formed as a plastics moulding so that the sides of its interior taper from top to bottom as is customary with plastics mouldings for moulding reasons, it is difficult to ensure that the ring seal adequately seals at the top of the vessel without the friction between the material of the seal and the side of the vessel becoming excessive as the piston descends towards the base .

One object of this invention is to avoid these problems .

According to this invention there is provided a beverage maker for the kind referred, wherein the separator piston disc and the peripheral ring seal are formed as a one-piece mesh disc having a major planar portion and a flared circumferentially extending peripheral portion which serves as the peripheral ring seal portion, the arrangement being such that the peripheral edge of the one-piece mesh disc is in sliding contact with the inner surface of the chamber wail and is displaced axially with respect to the major planar portion, being nearer to the base of the chamber than is that major planar portion. Preferably the major planar portion of the one- piece mesh disc is reinforced by radial spokes which project over the face of the major portion which is further from the peripheral edge. The one-piece mesh disc may be heat formed from plastics mesh material and its peripheral edge may be frayed.

A coffee maker in which this invention is embodied is described now by way of example by reference to the accompanying drawing which is a partly sectioned side elevation of the coffee maker.

The drawing shows that the coffee maker comprises a hollow vessel (10) in the form of an open topped jug having a pouring spout (11) and which is closed at its upper end by a lid (12) which is releasably fixed to brim of the jug. The lid (12) is formed by moulding. The interior of the vessel (10) is a substantially chamber. The vessel (10) is formed by moulding. As is usual with such hollow moulded products, the side walls of the vessel (10) taper slightly towards the base of the vessel (10).

A rotary cap (13) is retained against axial displacement relative to the lid (12) but can be rotated relative to the lid (12) within which it is mounted. A socket (not shown) is formed substantially f> co-axially in the rotary cap (13), the socket (15) opening downwards .

A four start thread leadscrew (14) is spigotted into the socket of the rotary cap (13) and depends therefrom through the center of the cylindrical chamber of the vessel (10) so that its lower end is close to the base (15) of the vessel (10). The thread is formed on the exterior surface of the leadscrew (14). The latter may be formed by moulding. Indeed the rotary cap (13) and the leadscrew (14) could be moulded as a one-piece component. Alternatively the leadscrew (14) may be produced by selecting a length of bar having a cross-section which is substantially square with shallow concave faces and by twisting that length of bar to form it into the leadscrew (14).

A nut member (16) is screw-fitted onto the lead screw (14). The nut member (16) is formed as part of a one-piece plastics moulding which also includes a number of radially extending ribs (17) of which two are shown in the drawing. The lower portion of the nut member (16) extends through the central aperture of an annular separator piston disc ( 18 so that the ribs (17) extend over the upper surface of a central planar portion (19) of the piston disc (18). The planar portion (19) is a major portion cf the piston disc (18). The remainder of the piston disc (18) comprises a flared circumferentially extending peripheral portion (21). The flared peripheral portion (21) presents an annular concave surface to the base (15) and has a peripheral edge (22) which is nearer to the base (15) than is the major planar portion (19). The radial ribs provide reinforcement for the major planar portion (19).

The annular separator disc (18) is heat formed from a thin plastics mesh material. The mesh material of the separator disc (18) is cut from a sheet of such thin mesh material before it is heat formed into the disc (18). The cut edges would have been frayed edges, comprising circumferentially spaced strands of the plastics material of the mesh. Those frayed edges are tidied up during the heat forming process, individual strands of the plastic material being fused together one to another but the resultant edges will still be frayed rather than being formed into a circumferentially continuous hoop. The mesh is joined to the nut member (16) at the edge of the central aperture as well as to the undersides of the ribs (17). It may be so joined as part of the moulding process by which the nut member (16) with its ribs (17) was formed. Alternatively it may be so joined by bonding. In another embodiment the mesh may be clamped to the undersides of the ribs (17) by similar ribs below the mesh.

A rod (23) depends from the lid (12) substantially parallel to the leadscrew (14) and to one side of the leadscrew (14) partway between the leadscrew (14) and the side of the vessel (10). The rod (23) is a sliding fit in an aperture (24) which extends through one of the ribs (17) and the planar portion (19) of the mesh material separator disc (18). A link (25) is joined at one end to the bottom of the rod (23). The lower end of the leadscrew (14) is journalled in the link (25). If the cross-section of the vessel (10) is not circular, the bar (23) ensures that the lid (12) and the annular separator piston

(18) are aligned one with another for insertion into the vessel.

In order to charge the coffee maker for use, the lid (12), the rotary cap (13), the leadscrew (14), the rod (23), the link (25) and the piston disc (18) are removed from the vessel (10). Coffee grains are introduced into the vessel (10) through the open top. The vessel (10) is filled with water to just below the spout (11). The lid (12), the rotary cap (13), the leadscrew (14), the rod (23), the link (25) and the piston disc (18) are refitted with the piston disc (18) adjacent the lid (12). When the coffee is brewed and ready to drink, the user rotates the upper portion of the rotary cap (13) thereby rotating the leadscrew (14) and driving the piston disc (18) downwards towards the base (15) of the vessel (10) whereby to separate the residue of the coffee grains from the liquid, liquid coffee being allowed to pass through the interstices of the mesh material of the piston disc (18) during the travel of the piston disc (18). The link (25) limits downwards travel of the piston disc (18) and ensures that the latter is removed from the vessel (10) with the lead screw (14) for charging and cleaning. The bar (23) constrains the piston (18) from turning with the leadscrew (14). Use of a multi-start thread, especially a four-start thread gives a larger displacement of the piston disc (18) for rotation of the cap (13) than would be achieved by a single start thread. It also gives a more even distribution of load around the leadscrew (14) so that the action of the mechanism is smooth. The fabric nature of the mesh material of the peripheral portion (21) of the annular separator piston (18) and its frayed edge (22) cater for the taper of the interior of the vessel (10). Because of the fabric nature of the mesh material and the frayed edge (22), the peripheral portion (21) readily conforms to the inner surface of the sides of the vessel against which it is held by the pressure of the mixture of undissolved coffee grains and liquid as it is slid along the inner surface of the vessel towards the base (15) with movement of the piston disc (18) towards the base (15). The fact that the peripheral portion (21) is circumferentially continuous ensures that it provides a circumferentially continuous barrier to the passage of coffee grains between it and the inner wall of the vessel (10) and thus serves as a peripheral ring seal portion of the disc (18). The diameter of the frayed edge (22) is sufficient to ensure contact between the peripheral portion (21) and the inner surface of the sides of the vessel (10) at the top of the travel of the piston disc (18). Hence that contact will increase with movement of the piston disc (18) towards the base (15). The piston disc (18) contributes to the location of the leadscrew (14) within the vessel (10).

The rotary cap (13) could be replaced by an arm which is fixed to the top of the leadscrew (14) that projects up through the central aperture of the lid II (12). The arm may have a rotary knob at its outer end. Alternatively the rotary cap (12, may be provided with such an arm which may be hinged to the cap so that it can be folded and stowed within the planform area of the upper portion of the cap (13) and folded out only when it is needed to turn the leadscrew ( 14 ) .

Rotation of the leadscrew (14) could be powered either mechanically or electrically aε an alternative to the manual operations described above.

The annular lid could be simply seated on the brim of the vessel (10) rather than being releasably fixed thereto as described above. The vessel could be made of glass. The leadscrew could be machined from stainless steel. The annular separatcr piston disc (18) could be formed from an appropriate thin woven metal mesh rather than from the thin plastics mesh material described above. The annular separator piston disc could be incorporated in a conventional piston at an end of a rod by which it is driven down the cylindrical chamber by being pushed tcwards the base (15)

Claims

1. A beverage maker which includes a chamber having a closed end (15), a pouring spout (11) spaced from the closed end (15) and a separator piston disc (18) which is provided with a seal around its periphery and which is slidable within the chamber between the pouring spout (11) and the closed end (15), the separator piston disc (18) being permeable to water and the beverage whilst being impenetrable to solid raw material from which the beverage is made and being adapted to be driven towards the closed end (15) of the chamber, the seal being operably co-operative with the sides of the chamber so as to seal against passage of the raw material between the disc (18) and the sides of the chamber from below the disc (18), the arrangement being such that the solid raw material is placed in the chamber between the closed end (15) and the separator piston disc (18) and the chamber is filled with hot water which interacts with raw material to form the beverage, the separator piston disc (18) being driven towards the closed end (15) to separate the residue of the raw material from the resultant beverage, characterised in that the separator piston disc (18) and the peripheral ring seal are formed as a one-piece mesh disc having a major planar portion (19) and a flared circumferentially extending peripheral portion (21) which serves as the peripheral ring seal portion, the arrangement being such that the peripheral edge (22) of the one-piece mesh disc (18) is in sliding contact with the inner surface of the chamber wall and is displaced axially with respect to the major planar portion (19), being nearer to the base (15) of the chamber than is that major planar portion (19).

2. A beverage maker according to claim 1, wherein the major planar portion (19) of the one-piece mesh disc (18) is reinforced by radial spokes (17) which project over the face of the major portion (19) which is further from the peripheral edge (22).

3. A beverage maker according to claim 1 or claim 2, wherein the one-piece mesh disc (18) is heat formed from plastics mesh material.

4. A beverage maker according to any one of claims 1 to 3, wherein the peripheral edge (22) of the one- piece mesh disc (18) is frayed.