Fully automatic coffee machine with decoupled grinder

Abstract

A fully automatic coffee machine for household purposes with a grinder (2) for grinding roasted coffee beans, with a dispensing chute (13) for ground coffee, with a brewing unit and with a brewing pot of the brewing unit for receiving ground coffee from the dispensing chute (13), with a pivoting capability of the dispensing chute (13) between a starting position remote from the brewing pot, in which the dispensing chute is remote from the brewing unit, and an end position close to the brewing pot, in which the dispensing chute (13) is positioned on the brewing unit so that ground coffee passes from the dispensing chute (13) into the brewing pot, with a pivoting capability, in particular a rotatability, of the grinder (2), and with an operating axis of the grinding discs (7) of the grinder (2), is further developed in such a way that the operating axis is at the same time a rotation axis of the grinder (2) for rotating the dispensing chute (13) from the starting position to the end position.

Description

The invention relates to a fully automatic coffee machine, in particular for household purposes, having at least one grinding mechanism for grinding roasted coffee beans, having a discharge shaft for grinding material such as coffee powder or ground coffee beans, having a brewing unit and having a brewing pot of the brewing unit for receiving grinding material from the discharge shaft. The grinding mechanism is arranged in a regularly stationary manner within the fully automatic coffee maker.EP 608 804 B1 shows and describes an automatic coffee machine for preparing a coffee beverage in which coffee beans are ground into coffee powder in the grinding chamber of a coffee grinder. The coffee powder then passes via a filling chute into a infusion chamber, where it is compressed by a filtering piston and an infusion piston. The coffee beverage flows out of the infusion chamber. The coffee grinder, its grinding chamber and the filling chute form an assembly which is horizontally displaceable between a starting position, in which the coffee beans pass from the discharge hopper into the grinding chamber, and an end position, in which the coffee powder passes from the grinding chamber via the filling chute into the infusion chamber.Further coffee machines are known, for example, from DE 21 2013 000 025 U1 and DE 33 18 302 A1 and also contained in the post-published DE 10 2022 126 349 A1.The object of the invention is to make possible a simpler construction for the reliable and complete transport of grinding material from the grinding mechanism into the brewing chamber.This object is achieved in the fully automatic coffee machine mentioned at the beginning according to the invention by a pivotability of at least the discharge shaft of the grinding mechanism between an initial position remote from the brewing pot and an end position close to the brewing pot. In the starting position remote from the brewing pot, the dispensing shaft is removed from the brewing unit, so that it in particular cannot only dispense any grinding material into the brewing pot, but in particular is also outside of any water vapor that possibly rises therefrom, which could precipitate in the dispensing shaft and thus could lead to undesired moistening of the grinding material transported thereon. In the end position close to the brewing pot, on the other hand, the dispensing shaft is positioned, in particular directly, on the brewing unit, so that grinding material from the dispensing shaft reaches the brewing pot as intended.The invention is therefore directed to providing an initially desirably large distance between the brewing pot on the one hand and the grinding mechanism on the other hand by means of long chutes for conveying the grinding material. This is because long routes involve the risk of residues which can lead to small amounts of ground material in the brewing pot and which can be exposed to moisture, whereupon they can mold. Long paths can also lead to undesirable mixing of original and new ground material during a bean change.Rather, the invention follows the principle of replacing a distance, which is advantageous from the point of view of moisture, between the brewing pot on the one hand and the grinding mechanism on the other hand by movability of the dispensing shaft. Chutes requiring long and space can thereby be dispensed with. Nevertheless, the dispensing chute can be located at any time in a region protected from moisture. This is because it is only in action in its end position close to the brewing pot, but then at a point in time at which no greater moisture development occurs in the brewing pot. In its starting position remote from the brewing pot, on the other hand, water vapor can escape from the brewing pot without it reaching the dispensing shaft moved away from the brewing pot.The discharge shaft receives the grinding material to be conveyed from the grinding mechanism. In principle, the discharge shaft can take up the grinding material from the grinding mechanism and transport it with its movement from the starting position into the end position into the brewing pot. According to an advantageous embodiment of the invention, the fully automatic coffee machine can comprise a device for moving the grinding mechanism together with the dispensing shaft. For this purpose, the output shaft can be fixedly attached to a housing of the grinding mechanism. The grinding unit can then discharge the grinding material into the brewing pot via the discharge shaft in an operating position of the grinding unit or in the end position of the discharge shaft on a short path. In a rest position of the grinding mechanism or in the starting position of the dispensing shaft, on the other hand, the dispensing shaft and the grinding mechanism can be moved such that moisture from the brewing pot cannot reach at least the dispensing shaft.The movement of the discharge shaft and the grinding mechanism can in principle be arbitrary, for example consist of a vertical or horizontal displacement. According to the invention, the grinding mechanism is pivotable and in particular rotatable. The pivotability is understood as a generic term, which also includes the pivotability. While pivotability is understood to mean a movement about an axis outside the moving body, pivotability is understood to mean a movement of the body about an axis which-viewed in a sectional view of the body orthogonal to the axis-lies within the body, but does not necessarily lead through its center of gravity. In contrast to the horizontal or vertical displacement of the grinding mechanism together with the discharge shaft, the pivotability can offer structural space advantages, namely take up less installation space for the movement path. This is all the more so when the grinding mechanism has a compact design, so that it can travel a large distance on a small pivoting path and in particular the discharge shaft on the grinding mechanism within the fully automatic coffee maker.Known grinding units contain circular grinding disks which are rotated relative to one another about an operating axis of the grinding unit during operation. According to the invention, the operating axis of the grinding mechanism is at the same time an axis of rotation of the grinding mechanism for rotating the discharge shaft from the starting position into the end position and vice versa. Thus, if the operating axis of the grinding mechanism and the axis of rotation of its housing, on which the discharge shaft can be arranged, coincide geometrically, optimum utilization of space results. This is because the regularly largely cylindrical housing of the grinding mechanism requires a possibly small movement space when it rotates about its operating or rotational axis.In principle, a separate drive can be available for the operation of the grinding mechanism per se and for the rotation of its housing. According to a further advantageous embodiment of the invention, the same drive can serve for the grinding discs of the grinding mechanism about the operating axis on the one hand and for rotating the grinding mechanism about its axis of rotation on the other hand. This makes it possible to save a high design outlay for a drive, resulting in space advantages. The omission of a drive per se also makes the structure of the fully automatic coffee machine more cost-effective.According to a further advantageous embodiment of the invention, the fully automatic coffee machine can have rotation restrictors for limiting the rotational movement of the grinding mechanism between the starting position and the end position. The rotation limiters can consequently define the exact position of the grinding mechanism exactly in the starting position for protection against moisture of the discharge shaft and in the end position for discharge of grinding material through the discharge shaft into the brewing pot. In addition, for example, by actuating a changeover gear, they can serve to switch the drive from rotating the grinding unit together with the output shaft to operating the grinding disks within the grinding unit which is now stationary, and vice versa. The rotation limiters can thus assume a dual function, namely the definition of the starting position and the setting of the discharge shaft on the one hand and the switching over of the drive from the rotation of the grinding mechanism to its operation on the other hand. They can thus contribute to a particularly compact construction of the fully automatic coffee maker.According to a further advantageous embodiment of the invention, the fully automatic coffee machine can comprise a device for reversing the direction of rotation of the drive. The device can advantageously be combined with the rotation limiters or the change-over gear, so that no additional structural complexity has to be operated for the corresponding control of the drive. In a simple case, after at least one of the two positions of the output shaft has been reached, the electrical polarity of an electric motor as a drive can be reversed, for example, as a function of a predefined or adjustable time period or as a function of a number of revolutions.According to a further advantageous embodiment of the invention, the fully automatic coffee machine can be designed or designed such that the grinding mechanism requires a higher torque during grinding than the rotation of the grinding mechanism between the starting position and the end position of the dispensing shaft. According to the invention, the rotation of the grinding mechanism and the rotation of the grinding disks or at least one grinding disk of the grinding mechanism can be effected by the same drive, but depending on the torque required for this purpose. The drive thus functions as a function of torque or as a function of torque, in that the movement that requires the lower torque is first carried out.The grinding mechanism can be designed such that its rotational movement requires a lower torque than its intended operation. The drive can thus, after its activation, initially cause a rotation of the grinding mechanism from the starting position into the end position of the discharge shaft. As soon as a rotation limiter blocks the rotation of the grinding mechanism, the torque therefor increases to infinity. It is thus higher than the torque required for the intended operation of the grinding mechanism. The drive consequently subsequently drives the grinding of the grinding mechanism.After a reversal of the direction of rotation of the drive, the return of the grinding mechanism to the starting position is initially not a hindrance to a rotation limiter. The drive consequently causes the grinding mechanism to rotate into the starting position. After the completion of the rotary movement by a rotary limiter, the drive can also be switched off because grinding of the grinding mechanism is then usually not necessary.A design according to the invention of the respective torques can make a separate changeover transmission unnecessary, whereby the design of the fully automatic coffee machine can be simplified and its production can be made more cost-effective.The drive of the grinding mechanism can be designed, for example, as a belt drive or as a gear drive. According to a further advantageous embodiment of the invention, the drive can be a worm drive of the grinding mechanism. The worm wheel of the worm gear can be assigned to the motor on the output side and drive a gearwheel which meshes with it and which can be coupled directly to one of the two grinding disks of the grinding mechanism. The worm drive can be designed to be particularly robust and compact and at the same time offer a suitable reduction in the engine speed, for example of an electric motor.According to a further advantageous embodiment of the invention, the fully automatic coffee machine can comprise two stops as rotation restrictors which project radially outwards from the housing of the grinding mechanism and cooperate with a stop in the fully automatic coffee machine fixed to the appliance. The radially protruding rotation limiters can be designed as ribs on the housing of the grinding mechanism. They can thus be designed to be very simple in design and thus cost-effective, but also space-saving.The principle of the invention is explained in greater detail below by way of example with reference to a drawing. In the drawing, the following are shown: FIGS. 1 and 2 : show a grinding mechanism and drive unit according to the invention together with the discharge shaft in a starting position of the grinding mechanism, FIGS. 3 to 5 show the unit in an end position, FIGS. 6 and 7 show the unit in a position between the starting position and the end position.FIGS. 1 to 7 show a grinding mechanism and drive unit according to the invention of a fully automatic coffee machine, which is composed of a drive 1 and a grinding mechanism 2. The drive 1 is formed by an electric motor 3 which is mechanically coupled to the grinding mechanism 2 via a worm gear 4. On the output side, the motor 3 has a worm shaft 5 which meshes with a worm wheel 6 of the grinding mechanism 2.The grinding unit 2 accommodates two circular grinding disks 7 in a largely cylindrical grinding unit pot or housing 8, and the grinding disks 7 are situated concentrically with and above one another in the housing 8, so that they are rotatable relative to one another about a largely perpendicular operating axis (not shown). For this purpose, the lower grinding disk 7 in FIG. 1 is at the same time designed as a worm wheel 6, i.e. it meshes circumferentially with the worm shaft 5, while it is mounted rotatably with respect to the housing 8, while the upper grinding disk 7 is installed fixed to the housing.The housing 8 of the grinding mechanism 2 itself is likewise rotatably mounted according to the invention, so that it can be rotated about the operating axis of the grinding disks 7. For this purpose, an annular collar 9 protrudes from the housing 8 on the outside and radially outwards. During operation, it rests or slides on a guide 10, which is likewise annular but fixed in relation to the fully automatic coffee machine and surrounds the housing 8 on the circumference. For space reasons, the guide 10 is interrupted in the region of the worm gear 4.The collar 10 carries two pin-shaped stops 11 which cooperate with two rib-shaped stops on the housing 8 as rotation limiters 12.1, 12.2. The stops 11 protrude from the top of the collar 10 and, when the housing 8 is rotated through approximately 90°, come into mutual contact with the rotation restrictors 12.1, 12.2 protruding radially from the housing 8, so that a further rotation of the housing 8 is blocked. In this sense, the first rotation limiter 12.1 defines a rest or starting position of the grinding unit 2 according to FIGS. 1 and 2.On the outside and largely tangentially, a tunnel-shaped discharge shaft 13 protrudes from the housing 8 of the grinding mechanism 2. It has a rectangular cross section and is quite short, so that it projects radially outwards beyond the collar 10 only by about twice its width. During operation, the output shaft 13 transports ground material from the interior of the housing 8 to the outside into a brewing pot, not shown, of a brewing unit of the fully automatic coffee maker. With suitable dimensioning, the output shaft 13 itself can also function as a rotation limiter.The discharge shaft 13 is formed in one piece or in one piece with the housing 8 of the grinding unit 2. If the housing 8 rotates with its guide 10 about the operating axis, the output shaft 13 pivots about the same operating axis and about the same angle of rotation as the housing 8.At its end facing away from the housing 8, the dispensing shaft 13 has an opening 14, which constitutes a further opening of the housing 8 in addition to an upper filling opening 15 for coffee beans. Because of its proper proximity to the brewing pot of the brewing unit when delivering ground material, the mouth opening 14 of the dispensing shaft 13 is in principle subject to the risk of being exposed to the moisture from the brewing unit. In order to eliminate this risk, the dispensing shaft 13 can be pivoted from an initial position according to FIGS. 1 and 2 into an end position according to FIGS. 3 to 5.The starting position is characterized in that the dispensing shaft 13 or its mouth opening 14 is remote from the brewing unit and at least lies in a region within the fully automatic coffee machine which is protected against moisture, in particular against water vapor rising from the brewing unit. The starting position is at the same time the idle position of the grinding mechanism 2, in which it is not in operation during a preparation process of the fully automatic coffee machine.In the end position according to FIGS. 3 to 5, on the other hand, the discharge shaft 13 performs its intended function in which it discharges ground material from the grinding mechanism 2 into the brewing pot. The end position of the dispensing shaft 13 is thus distinguished by a direct proximity to the brewing pot, so that the ground material from the grinding mechanism 2 can pass completely and without loss through the dispensing shaft 13 and can pass into the brewing pot. The proximity of the opening 14 to the brewing pot in the end position is largely without problems, because during the filling of the brewing pot virtually no moisture escapes from the brewing unit, which could precipitate in the discharge shaft 13 or on the ground material.In addition to the skillful selection of the starting position and end position of the dispensing shaft 13 in the course of a beverage preparation process, a further particular feature of the invention is that no dedicated drive is required for the movement of the dispensing shaft 13 between the two positions required therebetween. This is because the invention uses the drive 1 or the motor 3 of the grinding mechanism 2 for this purpose.Starting from the starting position according to FIGS. 1, 2, the dispensing shaft 13 moves together with the housing 8 in a leftward rotation L in a direction towards the end position according to FIGS. 3 to 5 by driving the motor 3 in a working rotation A. The worm shaft 5 thereby sets the worm wheel 6 in a rotational movement about its operating axis. The worm wheel 6 simultaneously represents the lower of the two grinding disks 7. The two grinding disks 7 are pressed against one another under a certain prestress, so that the lower of the two grinding disks 7 carries along the upper grinding disk 7, which is mounted fixed to the housing, because of the frictional connection between them, and also drives the housing 8 of the grinding mechanism 2 in rotation with it. The dispensing shaft 13 thus also pivots in a direction towards the end position following the left rotation L.The joint leftward rotation L of the housing 8 and the grinding disks 7 about the operating axis takes place until the second rotation limiter 12.2 reaches the associated stop 11 on the guide 10 and blocks the further leftward rotation L. The end position of the dispensing shaft 13 according to FIGS. 3 to 5 is thus reached, in which it has reached the brewing pot.The motor 3 nevertheless maintains its working rotation A and rotates the worm wheel 6 and thus the lower grinding disc 7 further about its actuation axis. However, because the rotation of the housing 8 is blocked and with it also the rotation of the upper grinding disc 7, the grinding mechanism 2 is thereby put into operation in order to produce grinding material. However, the operation of the grinding unit 2 requires a higher torque of the motor 3 than the rotation of the housing 8, in order to overcome the frictional engagement between the grinding disks 7 that is necessary for operation.Since the dispensing shaft 13 is in its end position close to the brewing pot, the ground material from the grinding mechanism 2 reaches the brewing pot via the short dispensing shaft 13 in a short path.The duration of the working rotation A of the motor 3 since reaching the end position controls a control device of the fully automatic coffee maker in a conventional manner.After the grinding operation is complete, the control device reverses the direction of rotation of the motor 3 into a final rotation E. Now the motor 3 again has a lower resistance to rotation, namely that of the rotation of the housing 8 about the operating axis, but in a right-hand rotation R. It rotates the housing 8 and with it the dispensing shaft 13 back into the starting position according to FIGS. 1, 2 and takes place until the first rotation limiter 12.1 comes to rest against the second stop 11 on the guide 10. The starting position is thus reached and a further right-hand rotation R is blocked. If no further grinding operation is to follow in this position, the control device switches off the motor 3 or reverses its direction of rotation for a further preparation operation.Since the preceding grinding unit and drive unit described in detail is an exemplary embodiment, it can be modified to a great extent by the skilled person in the art in the usual manner without departing from the scope of the invention. In particular, the specific embodiments of the rotation limiters, of the transmission or of the motor can also be carried out in a different form than in the one described here. The grinding mechanism can likewise be designed in another form if this is necessary for space reasons or design reasons. Furthermore, the use of the indefinite article "a" or "an" does not exclude that the features in question can also be present multiple or multiple times.List of reference characters1 Drive 2 Grinding mechanism 3 Motor 4 Worm gear 5 Worm shaft 6 Worm wheel 7 Grinding disks 8 Housing 9 Collar 10 Guide 11 Stop 12.1, 12.2 Rotation limiter 13 Output shaft 14 Opening 15 Filling opening A Working rotation E Final rotation L Left rotation R Right rotation

Claims

Fully automatic coffee machine for domestic purposes, having a grinding mechanism (2) for grinding roasted coffee beans, having a discharge shaft (13) for grinding material, having a brewing unit and having a brewing pot of the brewing unit for receiving grinding material from the discharge shaft (13), having a pivotability of the discharge shaft (13) between a starting position remote from the brewing pot, in which the discharge shaft is removed from the brewing unit, and an end position close to the brewing pot, in which the discharge shaft (13) is positioned on the brewing unit, so that grinding material passes from the discharge shaft (13) into the brewing pot, having a pivotability, in particular a pivotability, of the grinding mechanism (2), and having an operating axis of the grinding discs (7) of the grinding mechanism (2), characterized in that:, the operating axis is at the same time an axis of rotation of the grinding mechanism (2) for rotating the output shaft (13) from the starting position into the end position.Fully automatic coffee machine according to claim 1, characterised bya device for moving the grinding mechanism (2).Fully automatic coffee machine according to claim 1 or 2, characterised bythe same drive (3) for the grinding discs (7) of the grinding mechanism (2) on the one hand and for the rotation of the grinding mechanism (2) on the other hand.Fully automatic coffee machine according to claim 1 or 3, characterised byrotating limiters (12) for limiting the rotary movement of the grinding mechanism (2) between the starting position and the end position of the dispensing shaft (13).Fully automatic coffee machine according to one of claims 3 or 4, characterised bya device for reversing the direction of rotation of the drive (3).Fully automatic coffee machine according to one of claims 3 to 5, characterised in that the grinding mechanism (2) requires a higher torque during grinding than the rotation of the grinding mechanism (2) between the starting position and the end position.Fully automatic coffee machine according to one of claims 1 to 6, characterised bya worm drive (3, 4) of the grinding mechanism (2).Fully automatic coffee machine according to one of claims 4 to 7, characterised bytwo stops as rotation restrictors (12) which project radially outwards from a housing (8) of the grinding mechanism (2) and cooperate with a stop (11) in the fully automatic coffee machine fixed to the appliance.

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