GB2329825A - Coffee maker with brew strength control - Google Patents

Abstract

A domestic coffee-making appliance comprises a tank for fresh water, and a flow heater connected both to the tank and to a riser tube which conveys hot water from the flow heater up to a drip-feed head which is positioned above a coffee-filter receiving station. The drip-feed head delivers hot water that is showered on to the coffee solids in the filter, and brews coffee which is collected in a carafe. In order to enable a user of the appliance to select the strength of the brewed coffee, the drip feed head includes a spreader member 16, rotatable with respect to an apertured plate member 14, and arranged so that, in dependence upon the relative rotational position (selected by the user) of the spreader member relative to the plate member, the hot water is showered on to the coffee solids through apertures at selected radial locations of said plate member. The spreader member is disposed above the plate member, and is formed with downwardly dependent walls configured to divert hot water to and through selected apertures, depending on the user-selected rotational position of the spreader member and the plate member; the plate member being of substantially flat construction without traps for stale water, scum or scale.

Description

Domestic Appliance For Making Hot Beverages This invention relates to domestic appliances for making hot beverages, such as coffee for example.

Domestic coffee-making appliances typically comprise a tank which is charged with fresh water, and a flow heater connected both to the tank and to a riser tube which conveys hot water from the flow heater up to a distributor (or so-called "drip-feed") head which is positioned above a coffee-filter receiving station.

Hot water drips from the head onto ground coffee retained in the filter and then, after running down through the ground coffee and through the filter, into a vessel such as a carafe. Typically, the carafe is supported on a base which is heated, often by the heating element of the flow heater referred to previously, and a valve is disposed under the receiving station and above the carafe to prevent hot water dripping onto the heated base unless the carafe is properly positioned thereon.

Appliances of this kind work well and have gained wide acceptance. One drawback associated with such appliances, however, is that (aside from the ability to choose how much coffee to place in the filter in the first place) they provide the user with little or no opportunity to exert control over the strength of the coffee. This drawback has been recognised and addressed in recent years, but current solutions have disadvantages in that they are either crude, being based upon dilution of the coffee in the carafe by diversion of some of the heated water direct to the carafe, rather than to the drip-feed head and through the ground coffee, or rather expensive to manufacture bearing in mind the modest price levels that have been established for such appliances.

This invention aims to overcome the above-mentioned drawback and disadvantages, and to provide a domestic appliance for making hot beverages in which the strength of the beverage is readily adjustable by the user, by means of an efficient mechanism which is cost-effective to produce.

According to the invention there is provided a domestic appliance for making hot beverages, the appliance comprising a source of hot water, a brewing station at which the hot water is brewed with solids of the beverage, the brewing station being disposed beneath an outlet for said hot water and itself having an outlet through which the brewed beverage can pass into a collecting vessel, wherein the brewing station has a mouth of extended lateral dimensions disposed to receive said hot water, and a user-operable distribution device for selectively directing said water to different lateral regions of said mouth, wherein the distribution device comprises a substantially discoidal plate member having lateral dimensions similar to those of said mouth and formed with a plurality N of sets of apertures therein, each set containing a plurality of apertures disposed at respective radial distances from the centre of the plate, and a spreader member juxtaposed with said plate member and having N pairs of radially extending walls depending therefrom towards the plate member and a peripheral wall circumferentially linking the pairs of walls to form an inner wall of a gallery into which said hot water can issue and presenting N exits for said hot water from said gallery, one exit between each pair of radial walls, and user-controllable means for causing relative rotation between the plate member and the spreader member so that, at each of a plurality of relative rotational positions of said plate member and said spreader member, said hot water is preferentially directed onto the mouth of the mixing station through a corresponding aperture of each of said sets.

In order that the invention may be clearly understood and readily carried into effect, one embodiment thereof will now be described with reference to the accompanying drawings, of which: Figure 1 shows, in general view, a typical coffee-making appliance and some of its principal component parts, Figure 2 shows, in detailed perspective view, the components of a drip-feed head for use in an appliance according to one example of the invention, and Figure 3 shows the underside of a spreader member comprising one of the components illustrated in Figure 2.

Referring now to Figure 1, the coffee-making appliance shown comprises a heated base 1 on which stands a carafe or jug 2, positioned to receive the brewed coffee. The coffee is kept warm by the heat applied to base 1 which heat, as mentioned previously, is advantageously supplied by the same electrical heating element as is used to heat the water with which the coffee is to be brewed. The heating element (not shown in Figure 1) is typically horseshoe-shaped, and located proximate to the underside of the base 1 and contained within a suitable housing section . A switch 3 is provided by means of which power can be supplied to the heating element.

Above the location of the carafe 2 is a housing portion 4 which is internally shaped into conical or similar form with a wide mouth portion at the top and adapted to receive a filter device, usually a mesh of plastics material, into which frrst a paper filter and then ground coffee is placed. The housing portion 4 swings outwardly to enable the filter and coffee to be added prior to brewing, and removed afterwards.

Behind the housing portion 4 is located a water tank which holds sufficient water to fill the carafe 2. The tank is accessed through a raisable lid 5 and is usually charged with water by means of the carafe itself.

A water feed tube (not shown) runs from the bottom of the water tank and is connected as the inlet to a water tube, closely thermally connected to and usually following closely the horseshoe shape of the aforementioned heating element, and fonning part of a flow heater. The outlet of the water tube is connected, via a riser tube, to a drip-feed head disposed above the housing portion 4 and positioned so that hot water from the flow heater, having travelled up the riser tube, drips onto the coffee contained in the filter device. The hot water permeates through the coffee and then, having brewed, drips into the carafe via a valve which is opened only when the carafe is properly positioned on the base 1.

Referring now to Figure 2, the riser tube is shown at 10, and it terminates, via a rightangled distributor 11, at an orifice 12 through a circular wall 13 which is integrally formed with and upstanding from a discoidal plate member 14. Wall 13 defines, together with another circular wall 15 that is formed integrally with, and downwardly dependent from, a spreader member 16, a circular gallery region 17 into which the hot water issues.

Plate member 14 is formed with a central hub 18 surrounded by a substantially flat region 19 that dishes slightly downwards towards the hub and is defined at its outer periphery by a vertical wall 20 extending downwards, as shown in the drawing, to create a circular down-step. The wall 20 defines the inner periphery of the gallery 17, and is disposed close to, and coaxial with, the inner face 15b (see Figure 3) of wall 15 of the spreader member 16 when the pate member 14 and the spreader member are mounted, as is intended, in close juxtaposed relationship. Around wall 20 is a flat region 21 designed to accept and bear against the flat surface 15a (see Figure 3) of the wall 15.

The region 19 of the plate member 14 is formed with a plurality N, in this example 3, of sets 22, 23 and 24 of apertures such as 25. In this example, each set contains seven identical apertures such as 25, and the apertures of each set are disposed along identical, somewhat sinuous tracks extending in each case from a position close to the wall 20 to a position close to hub 18. The sets of apertures are equi-angularly distributed around the region 19.

The spreader member 16 is capable of rotational movement with respect to the discoidal member 14 and is mounted in operation so that the inner circular surface 15b of the wall 15 closely surrounds but does not touch the wall 20, whereas the flat part 15a of wall 15 makes contact with the flat region 21 and wipes around it when the spreader member 16 is rotated relative to the discoidal member 14.

As is best seen in Figure 3, which shows the underside of the spreader member 16, the wall 15 is not continuous, but forms circumferential links between three pairs 26, 27 and 28 of radially-extending walls, each pair intended to cooperate with a respective one of the sets 22, 23 and 24 of apertures such as 25 in member 14. Each pair of walls opens into the gallery 17 formed between the walls 13 and 15, and can thus convey water radially of the members 14 and 16. The flat parts such as 26a of the pairs 26, 27 and 28 of radially extending walls wipe on the surface 19, being slightly inclined to match the aforementioned slight dishing of surface 19, and thus communicate, at different angles of rotation of member 16 relative to member 14, with different apertures in the respective sets with which they cooperate. It will be seen that there is a step such as S at the junction of the flat part 15a of wall 15 with the flat parts such as 26a of each of the pairs of radial walls such as 26. This is to accommodate the step wall 20 in member 14, and thus allow the flat surface 15a to run on the region 21 whilst the flat surfaces such as 26a wipe around the elevated region 19.

The arrangement is such that each pair of radially extending walls is moved rotationally relative to the region 19 so as to progressively communicate with apertures such as 25 at different radii. In this example, each pair of walls communicates with an aperture at a given radius from the hub 19 at a given angular position of plate 16 relative to plate 14.

In other words, at an initial angular position of member 16 relative to member 14, each pair of walls 26, 27 and 28 communicates with the outermost aperture 25 of its respective set. Angular movement of member 16 relative to member 14 causes each pair of walls to communicate with the aperture at the next greatest radius from hub 18, and so on until the full extent of angular movement of member 16 brings the pairs of walls into communication with the innermost apertures 25 of their respective sets. As will appear later, there is advantage in arranging for the flow of water to move progressively, rather than discretely, from apertures at one radius to those at another.

By this means, the hot water that issues from the aperture 12 into the gallery 17 is guided, in dependence upon the angular position of member 16 relative to member 14, to and through apertures at a selected radius from the hub 18, thereby causing the hot water to drip onto the ground coffee held in the brewing station at differing zones of the mouth thereof. The apertures such as 25 are countersunk, or otherwise treated, from the underside of the member 14 to assist in resisting creepage of the water issuing through those apertures across the underside of the member 14.

The rotational movement of member 16 is effected by the user by means of a control knob 29 that is fitted to an upstanding, central boss 30 on the member 16. A fixed cover plate 31, secured to the member 14, is interposed between the knob 29 and the member 16. This cover plate 31 is formed with a stop 32 on its upper surface to cooperate with one or more projections such as 34 on the underside of the knob 29 to limit the extent of angular travel of the member 16 to that sufficient to permit each of the pairs 26, 27 and 28 of radial walls on the underside of member 16 to communicate with all of the apertures in its respective set 22, 23 or 24. Plate 31 is also formed, on its underside, with a ring of teeth (not shown) which are engaged by three prongs 34, 35 and 36 upstanding from the upper surface of the member 16 to provide tactile indexing when the member 16 is rotated. The prongs are rendered somewhat resilient, to ease their movement over the ring of teeth on the underside of the cover plate 31, by the formation of a respective pair of arcuate slots, such as 37 and 38, to either side of each. In this example, there is no direct correlation between the dimensions of the teeth engaged by prongs 34-36 and the angular movements needed to shift the water flow from the apertures 25 at one radius of member 14 to those at another radius, though such correlation can be arranged if desired.

It is preferred in this example, however, to use the clicking motion imparted by the engagement of the prongs 34-36 with the aforementioned ring of teeth on the underside of the cover plate 31 to provide the user with a pleasing tactile operation and to resist uncontrolled angular movement.

Member 15 is formed with a hollow inner hub 39 which slots over and rotates around the hub 18 of member 14 to form a bearing for the relative angular movement between members 14 and 16.

Thus it will be seen that the overall arrangement is formed of relatively simple components, and the selection of the drip radius for the hot water is achieved reliably by the wiping action of the downwardly dependent walls of member 16 around the slightly dished, but otherwise completely flat surface 19 of member 14. There are no entrapment areas for stale water and/or scum or scale, as there might have been had, for example, upstanding walls or wall-portions been provided on surface 19. It has to be borne in mind that these components must operate reliably and exhibit longevity in a relatively hostile environment, and that this must be achieved in a cost-effective manner, from the standpoints of both component cost and ease of assembly.

It has been mentioned herein that the apertures such as 25 of each set follow a somewhat sinuous path. This need not be the case, and linear or other paths could be used if desired.

However, the sinuous form shown is preferred, as it is designed to ensure even transitions from apertures at one radius to those at the next radius, by partially uncovering the apertures at one radius before those at the previous radius are fully covered. This expedient also resists the build-up of pressure in the system that could occur if the arrangement were capable of adopting angular positions in which no apertures communicated with the gallery 17 via the pairs of walls 26-28. The same effect could, of course, be achieved by having linearly arranged apertures and sinuous walls 2628 in member 16.

Although the invention has been described with reference to a particular embodiment, it is not limited thereto, and modifications may be made without departing from the scope of the invention.

Claims (9)

1. CLAIMS 1. A domestic appliance for making hot beverages, the appliance comprising a source of hot water, a brewing station at which the hot water is brewed with solids of the beverage, the brewing station being disposed beneath an outlet for said hot water and itself having an outlet through which the brewed beverage can pass into a collecting vessel, wherein the brewing station has a mouth of extended lateral dimensions disposed to receive said hot water, and a user-operable distribution device for selectively directing said water to different lateral regions of said mouth, wherein the distribution device comprises a substantially discoidal plate member having lateral dimensions similar to those of said mouth and formed with a plurality N of sets of apertures therein, each set containing a plurality of apertures disposed at respective radial distances from the centre of the plate, and a spreader member juxtaposed with said plate member and having N pairs of radially extending walls depending therefrom towards the plate member and a peripheral wall circumferentially linking the pairs of walls to form an inner wall of a gallery into which said hot water can issue and presenting N exits for said hot water from said gallery, one exit between each pair of radial walls, and user-controllable means for causing relative rotation between the plate member and the spreader member so that, at each of a plurality of relative rotational positions of said plate member and said spreader member, said hot water is preferentially directed onto the mouth of the mixing station through a corresponding aperture of each of said sets.
2. 2. An appliance according to claim 1 wherein the outer wall of said gallery is carried by the circumferentially extending rim of said plate member.
3. 3. An appliance according to either of claims 1 and 2 wherein said plate member carries a hub, centrally located thereon, which co-operates with components carried by said spreader member to form a bearing for relative rotation between said spreader member and said plate member.
4. 4. An appliance according to any preceding claim wherein the apertures of each of said sets are disposed along respective sinuous paths on said plate member, and the respective walls of each of said pairs of radial walls are disposed on said spreader member in linear and parallel relation to one another.
5. 5. An appliance according to any of claims 1 to 3 wherein the apertures of each of said sets are disposed along respective linear paths on said plate member, and the respective walls of each of said pairs of radial walls are formed with a sinuous disposition on said spreader member.
6. 6. An appliance according to any preceding claim wherein the arrangement is such that, at all relative rotational positions attainable by the plate member and the spreader member, at least part of one aperture in each of sets is in communication with said gallery by way of the respective pairs of radial walls.
7. 7. An appliance according to any preceding claim wherein the plate member is treated, in the region thereof occupied by said apertures, to inhibit creepage of water radially across that surface of said plate member facing away from said spreader member and towards said brewing station.
8. 8. An appliance according to any preceding claim including a user-operable control knob for moving said spreader member rotationally relative to said plate member and means providing for the user a tactile indication of said rotational movement.
9. 9. An appliance according to any preceding claim and substantially as herein described.