Electric Coffee Maker With Anti-Drip Valve on Bottom of Filter

The invention relates to an electric coffeemaker with an anti-drip valve at the outflow opening of its filter funnel. Anti-drip valves of this type are designed to prevent coffee continuing to flow out of the coffee filter when the carafe is removed after the brewing process or the filter funnel is removed by swinging, lifting, or pulling it out of the coffeemaker, said funnel containing the ground coffee saturated with brewing water.

A number of coffeemakers with such anti-drip valves are known, having in common the feature that the valve is actuated by means of a sensing element which is deflected from its resting position by the lid of the carafe, when it is in its normal position, opening the valve. Typical actuating systems of this type are described and shown for example in German Pat. No. 25 38 685, German Utility Model No. 19 70 143, German AS No. 26 05 957, and German Utility Model No. 74 36 286. They all suffer from the disadvantage that they can achieve their goal of precise valve actuation only if a corresponding set of instructions for use is followed exactly, in other words, for example, when the carafe is removed from or replaced on the coffeemaker in a very specific direction and with a very specific orientation. In particular, this results in general in a slight awkwardness, namely that the sensing mechanism is deflected by the edge of the lid and the valve opens just as the carafe is being placed under the filter funnel or is only partially in this position. In addition the functional safety of the known devices is critically dependent on all of the dimensional tolerances both in the actuating system and in the coffeemaker housing, as well as the carafe and the shape of its lid, being maintained precisely, something which is not without its problems in the manufacture and assembly of the individual parts and often causes insuperable difficulties under wear conditions when spare parts are employed.

The goal of the present invention is to overcome all these difficulties and to create a coffeemaker with a drip-proof filter funnel which not only allows for considerable measurement tolerances in the cooperating parts of the mechanism, but is also operable in a completely foolproof manner, in other words requires no restrictive operating instructions.

In accordance with the invention, there is provided a coffeemaker with an anti-drip valve that is operated by a double lever linkage. This system has the advantage that the anti-drip valve can only open when two conditions are satisfied, namely, both the filter funnel and the carafe must be at least approximately in their specified working positions in order for the sensing lever according to the invention to cooperate with the activating lever according to the invention to open the anti-drip valve. Preferably, the so-called activating lever is brought into its working position by the filter funnel being inserted or swung into its working position. This is accomplished in particular by the filter funnel abutting a wall of the coffeemaker housing as it is inserted or swung into its working position, that the activating lever is deflected into its working position by parts of this wall. Preferably an up ramp is provided for this purpose on an appropriate point on the housing wall, on which ramp the activating lever rests only when the filter funnel has nearly reached its end position, and from which (ramp) is immediately lifts off as soon as the filter funnel is removed however slightly from its normal position. Preferably, the sensing lever is activated in such fashion that it is swung from a resting position in which it is not reachable by the lid of the carafe under any circumstances, into a sensing position by the activating lever, in which position the lid of the carafe can contact it to open the anti-drip valve as soon as the carafe has nearly reached its normal position. It is especially advantageous in this connection for the lever geometry to be selected so that the sensing lever, brought into and held in the sensing position by the deflection of the activating lever, is swung back into its resting position by the lid of the carafe, thereby opening the anti-drip valve as it swings back.

In an especially advantageous embodiment of the invention, the sensing lever is in its resting position, and the resting position of the activating lever, above the lower edge of the housing of the filter funnel, and is swung out into the space beneath this lower edge of the housing when the activating lever is deflected. This makes it possible to remove the filter funnel from the coffeemaker and to set it aside with the lower edge of its housing on a supporting surface, for example on a table top, without the sensing lever being deflected by the supporting surface and opening the anti-drip valve.

Especially favorable prerequisites regarding lever geometry, space requirements, and manufacturing cost can be achieved in the lever system according to the invention by having the deflection of the sensing lever and the activating lever takes place in the same operating plane running radially to the vertical filter axis, and also by virtue of the fact that the sensing lever, activating lever, and closing element of the anti-drip valve are so articulated with one another that the same spring element, engaging one of the two levers, pushes or pulls both levers into their resting positions and the sealing element into its closed position.

The up ramp which deflects the activating lever is preferably so mounted and designed that the activating lever rests on it as the filter funnel is inserted or swung in, as soon as the filter funnel has come within a maximum of 3 cm and a minimum of 1 cm of its working position. It has been found that when this spacing range is maintained, the remaining insertion or swinging travel of the filter funnel is sufficient fully to deflect the activating lever and thus activate the sensing lever into its sensing position by deflection. On the other hand, this ensures that the filter funnel is already sufficiently exactly positioned above the carafe when the sensing lever is deflected against the lid of the carafe, thus opening the anti-drip valve. Preferably the outer end of the sensing lever, deflected by the activating lever, is contacted by the circumferential edge of the carafe lid as soon as the radial distance of the carafe from its normal position falls below a value of a maximum of 5 cm and a minimum of 0.5 cm.

Another preferred embodiment of the invention is characterized by the fact that the articulation axis, by which the activating lever and the sensing lever are connected operationally, is mounted in a elongated hole which receives the displacements of this axis which occur as a result of the lever geometry. To achieve a high deflection travel of the sensing lever, which renders the valve actuating system according to the invention largely insensitive to variations in tolerances in the dimensions of the cooperating parts, the effective pivot axis of the sensing lever, in order for the latter to be deflected by the activating lever, is at least four times as far away from the outer end of the sensing lever as the articulation axis with which the activating lever engages the sensing lever.

Further advantageous embodiments, modifications, and designs of the basic principle according to the invention will be apparent from the attached drawing, wherein:

FIG. 1 is a side elevation, partially cut away, of a preferred embodiment of the coffeemaker according to the invention, whereby the individual parts essential to the invention are shown partially schematically for improved visibility;

FIG. 2 is a section through the coffeemaker according to FIG. 1 along line II--II.

FIGS. 3a to 3g show preferred lever systems according to the present invention and show schematically, always in the nonactivated state, i.e. with the anti-drip valve closed, how particular embodiments of the invention can be implemented advantageously (the system shown in FIG. 3a is identical to the arrangement shown in FIG. 1).

As is evident from FIGS. 1 and 2, the coffeemaker according to the invention consists of a housing 4 in which the usual parts such as water tank, through-flow heater, warming plate, cold water drop tube between the water tank and the through-flow heater, and the brewing water rise tube from the through-flow heater to the filter funnel are shown, as well as the removable filter funnel 3 and coffee carafe 5. The double lever system according to the invention which serves to actuate valve sealing element 3.20 is located beneath anti-drip valve 3.4 in filter funnel 3. This system consists primarily of sensing lever 1 and activating lever 2, which in the position shown has its outer end 2.2 deflected by up ramp 4.1 on the wall of housing 4 and which, by its deflection, has rotated sensing lever 1, coupled to it by elongated hole 2.3 and articulation axis 1.3, about its axis 1.10 which is integral with the filter, so that its outer end 1.2 is in contact with the edge of the carafe lid and abuts the latter.

The cooperation of the deflections of sensing lever 1 and activating lever 2 causes the horizontal axis 2.11 of activating lever 2, which is vertically movable in guide 3.1 which is vertical and integral with the filter, to be displaced downward against the force of spring element 3.3 which engages inner end 2.4 of the activating lever and is articulated at the other end on filter funnel 3. In this way, sealing element 3.20, which is articulated in the vicinity of axis 2.11, preferably flexibly, to activating lever 2, is pulled downward away from the opening of anti-drip valve 3.4 and assumes its open position, shown in FIG. 1.

If the situation shown in FIG. 1 is modified by removing carafe 5, spring element 3.3 causes the outer end 1.2 of the sensing lever simultaneously to fold downward and axis 2.11 together with closing element 3.20 of move upward, so that the latter seals anti-drip valve 3.4. If the situation shown is modified, on the other hand, by removing filter funnel 3, the outer end 2.2 of activating lever 2 slides downward from up ramp 4.1, and spring element 3.3 pivots activating lever 2 about its articulation axis 1.3, so that in this case also the vertically movable axis 2.11 moves upward in vertical guide 3.1 in the same manner as sealing element 3.20 and anti-drip valve 3.4 is closed. It is readily apparent from FIG. 1 that even a slight horizontal displacement of carafe 5 or of filter funnel 3 is sufficient to cause sensing lever 1 to slide off the edge of the carafe or activating lever 2 to slide off the up ramp, immediately causing closure of the anti-drip valve.

In addition to the especially advantageous two-lever system described above, which is shown once again in FIG. 3a in its resting position, a number of equally advantageous embodiments is possible within the framework of the present invention of which the most advantageous are shown in FIGS. 3b to 3g, always in their resting position. They differ individually especially in that activating lever 2 can be deflected downward instead of upward by up ramp 4.1 and also by the fact that instead of sealing element 3.20 which seals anti-drip valve 3.4 from below, a sealing element 3.21, which seals from above, can also be used, and differs in the lever geometry, i.e. the arrangement of the vertically displaceable pivot bearing integral with the filter, the elongated-hole articulation of the two levers, and the point of application of spring element 3.3 relative to filter axis A which is vertical and defined by anti-drip valve 3.4. In each case, deflection of activating lever 2 causes sensing lever 1 to be deflected downward.

The support bearing, which is preferably provided as a closure for vertical guide 3.1 of vertically movable axes 1.11 and 2.11, and is open at the top or bottom, may be positioned so that axes 1.11 and 2.11 abut it precisely when sealing elements 3.20 and 3.21 of anti-drip valve 3.4 have reached their sealing positions.

In all embodiments, up ramp 4.1 preferably has a locking notch into which the outer end 2.2 of activating lever 2 engages in sliding fashion at its highest deflection, i.e. when the filter funnel reaches its normal position the correctly designed lever geometry of the two-lever system according to the invention gives this latching action additional reinforcement precisely in the state in which it is important, namely when the carafe which has been inserted in the coffeemaker beneath the filter funnel is to be removed; the sensing lever deflected by the top of the carafe pushes activating lever 2 in the direction of up ramp 4.1, therefore reinforcing its application pressure in the latch for precisely the period of time required for the adhesive friction of the sensing lever on the top of the carafe to change to reduced sliding friction as the carafe is removed, therefore eliminating any danger that the filter funnel will be pulled out when the carafe is removed.

Preferably, the removable filter funnel according to the present invention is designed as a so-called swing filter, which can be swung out of the coffeemaker housing by pivoting about a vertical pivot axis mounted at its periphery. In an especially advantageous embodiment, this pivot axis is provided by two axle stubs 3.5 disposed one above the other, cooperating with bearing eyes 4.2 and facilitating easy mounting and removal of filter funnel 3. The preferred embodiments of these pivot bearings, considerably facilitate the handling of the filter funnel during removal and replacement, and the especially efficient manner in which it can be manufactured.