BEVERAGE PREPARATION MACHINE WITH SINGLE MOTOR ACTUATION

Abstract

The present invention concerns a brewing unit (5) for a beverage preparation machine (1), having several automated functionalities actuated by one single motor (16). The invention also concerns a beverage preparation machine comprising such an automated brewing unit.

Claims

1. A brewing unit for a beverage preparation machine comprising a plurality of cavity parts forming together a cavity for receiving an ingredient, at least one of the cavity parts being movable relative to the other(s) to open or close the cavity, the brewing unit comprising an injector for injecting into the cavity a fluid distributed through pipes from two alternative fluid sources located in the machine, said fluid for mixing with said ingredient and producing a beverage, the unit further comprises: a motor having an output shaft; a screw shaft fixed at its proximal end to the movable cavity part; a screw nut movable in rotation along a thread path of the screw shaft in a translation shaft arrangement, the screw nut being mechanically linked to the motor output shaft such that when the nut is rotated by the motor, it imparts a translation movement to the screw shaft and movable cavity part relative to the rest of the brewing unit, the screw nut comprising a protrusion or groove extending from, respectively into, its peripheral edge; a peristaltic fluid valve for conducting or blocking one or another fluid from the machine towards the injector through two flexible pipes corresponding to each of the two fluid sources, the peristaltic valve comprising two modules, each of which is adapted around a flexible pipe and comprises a mobile jaw for pinching the corresponding pipe, the module having a closing rocker body for pressing the jaw onto the pipe and closing the latter when pressed in a direction substantially parallel to the screw shaft, the module further having an opening rocker body for moving the jaw away from the pipe when pressed in a direction substantially parallel to the screw shaft, hence opening the pipe; and a preselector comprising: a rigid element pivotable between two angular positions and comprising first and second actuating pins, each pin extending towards a peristaltic valve module such that in the first position of the preselector the first actuating pin overlaps the opening rocker body of the first module in a plane perpendicular to the screw shaft, while the second actuating pin overlaps the closing rocker body of the second module in a plane perpendicular to the screw shaft, and in the second position of the preselector the first actuating pin overlaps the closing rocker body of the first module in a plane perpendicular to the screw shaft while the second actuating pin overlaps the opening rocker body of the second module in a plane perpendicular to the screw shaft; and a flexible tongue extending from the surface of the rigid element so as to catch the screw nut protrusion or groove at a point along the thread path that is distant from the extremities of the path by at least 1/16.sup.th of a nut rotation to form a reversible ratchet arrangement, the ratchet force being sufficient for pivoting the preselector element between its two angular positions, but insufficient for stopping the rotation of the screw nut further along the screw shaft during its rotation.

2. A brewing unit according to claim 1, comprising an encoder wheel and a sensor mechanically linked to the output shaft of the motor, for detecting the exact angular position of the screw nut along the screw shaft.

3. A brewing unit according to claim 1, wherein the output shaft of the motor and the screw nut are mechanically linked through a belt assembly.

4. A brewing unit according to claim 1, wherein the output shaft of the motor and the screw nut are mechanically linked through a gear shaft assembly.

5. A brewing unit according to claim 4, wherein the gear shaft assembly comprises at least a motor gear wheel fixed to the motor output shaft, and a drive gear wheel fixed to the screw shaft, the motor gear wheel being smaller than the screw shaft gear wheel.

6. A brewing unit according to claim 5, wherein the mechanical transmission further comprises a speed reduction gear wheel intermediate between the motor gear wheel and the drive gear wheel.

7. A brewing unit according to claim 1, wherein the catch point between the preselector tongue and the protrusion or groove of the screw nut, is located at a distance comprised between 1/16.sup.th and .sup.th of a screw nut rotation, from the proximal extremity of the screw shaft.

8. A brewing unit according to claim 2, wherein the encoder wheel is a light barrier wheel with increment teeth.

9. A brewing unit according to claim 1, which is detachable from the beverage preparation machine body.

10. A brewing unit according to claim 1, wherein the ingredient is contained in a single-dose disposable package.

11. A brewing unit according to claim 1, wherein one of the two fluid sources is cold/ambient water drawn from a reservoir of the machine, and the other is hot water drawn from the same reservoir and treated through a water heater.

12. A brewing unit according to claim 1, wherein, the jaw of each peristaltic valve module being spring-mounted such that when no pressure is applied to the rocker bodies, the jaw presses onto the pipe sufficiently to prevent fluid circulation therethrough, if the fluid pressure within said pipe is below a predetermined safety pressure lower than 3 bar, preferably lower than 2 bar.

13. A brewing unit according to claim 1, wherein the preselector element is pivotable between two angular position around an axis parallel to, or coaxial with, the screw shaft longitudinal axis.

14. A beverage preparation machine comprising a brewing unit comprising a plurality of cavity parts forming together a cavity for receiving an ingredient, at least one of the cavity parts being movable relative to the other(s) to open or close the cavity, the brewing unit comprising an injector for injecting into the cavity a fluid distributed through pipes from two alternative fluid sources located in the machine, said fluid for mixing with said ingredient and producing a beverage, the unit further comprises: a motor having an output shaft; a screw shaft fixed at its proximal end to the movable cavity part; a screw nut movable in rotation along a thread path of the screw shaft in a translation shaft arrangement, the screw nut being mechanically linked to the motor output shaft such that when the nut is rotated by the motor, it imparts a translation movement to the screw shaft and movable cavity part relative to the rest of the brewing unit, the screw nut comprising a protrusion or groove extending from, respectively into, its peripheral edge; a peristaltic fluid valve for conducting or blocking one or another fluid from the machine towards the injector through two flexible pipes corresponding to each of the two fluid sources, the peristaltic valve comprising two modules, each of which is adapted around a flexible pipe and comprises a mobile jaw for pinching the corresponding pipe, the module having a closing rocker body for pressing the jaw onto the pipe and closing the latter when pressed in a direction substantially parallel to the screw shaft, the module further having an opening rocker body for moving the jaw away from the pipe when pressed in a direction substantially parallel to the screw shaft, hence opening the pipe; and a preselector comprising: a rigid element pivotable between two angular positions and comprising first and second actuating pins, each pin extending towards a peristaltic valve module such that in the first position of the preselector the first actuating pin overlaps the opening rocker body of the first module in a plane perpendicular to the screw shaft, while the second actuating pin overlaps the closing rocker body of the second module in a plane perpendicular to the screw shaft, and in the second position of the preselector the first actuating pin overlaps the closing rocker body of the first module in a plane perpendicular to the screw shaft while the second actuating pin overlaps the opening rocker body of the second module in a plane perpendicular to the screw shaft; and a flexible tongue extending from the surface of the rigid element so as to catch the screw nut protrusion or groove at a point along the thread path that is distant from the extremities of the path by at least 1/16.sup.th of a nut rotation to form a reversible ratchet arrangement, the ratchet force being sufficient for pivoting the preselector element between its two angular positions, but insufficient for stopping the rotation of the screw nut further along the screw shaft during its rotation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Additional features and advantages of the present invention are described in, and will be apparent from, the description of the presently preferred embodiments which are set out below with reference to the drawings in which:

[0036] FIG. 1 is schematic perspective view of a beverage preparation machine according to the invention;

[0037] FIG. 2 is an enlarged perspective view of a capsule holder of a brewing unit according to the invention;

[0038] FIG. 3 is an enlarged perspective view of a brewing unit according to the invention, without the external casing, hence illustrating the arrangement of its constitutive elements;

[0039] FIG. 4 is a cut view along the plane A-A of FIG. 3,

[0040] FIG. 5 is a perspective bottom view of a needle plate in a brewing unit according to the invention;

[0041] FIG. 6 is a perspective top view of a needle plate in a brewing unit according to the invention;

[0042] FIG. 7 is a cut view along the plane B-B of FIG. 6,

[0043] FIG. 8 is a perspective view of the brewing unit according to the invention without the internal chassis, capsule holder nor fluid pipes, hence illustrating the arrangement of the motor, gears, shaft, movable cavity part and peristaltic valve modules;

[0044] FIG. 9A is a view similar to FIG. 8, without the movable cavity part, showing the insertion of the capsule holder relative to the other elements of the brewing unit, wherein the screw shaft is positioned in its high position;

[0045] FIG. 9B is a cut view along C-C of FIG. 9A;

[0046] FIG. 9C is a view similar to FIG. 9A with the screw shaft in the low position;

[0047] FIG. 10 is a perspective view of the motor, gear and screw shaft arrangement in an embodiment according to the invention;

[0048] FIG. 11 is a top view of the preselector and peristaltic valve modules arrangement, with the preselector in its first position and the screw nut in the reset position;

[0049] FIG. 12 is a view similar to FIG. 11, with the preselector in its second position;

[0050] FIG. 13 is a perspective view similar to FIG. 12;

[0051] FIG. 14A is a top view similar to FIG. 11 with the screw nut in the drive position;

[0052] FIG. 14B is a perspective view similar to FIG. 14A.

DETAILED DESCRIPTION OF THE INVENTION

[0053] In the field of the present invention, suitable gears can be of the spur gear type, but can also be external gears, helical or double helical gears, skew gears, bevel or spiral bevel gears, hypoid gears, worm gears, epicyclic or sun and planet gears, harmonic, cage, or magnetic gears, or a combination thereof.

[0054] By cold water, it is meant water that is at a temperature equal to, or lower than ambient temperature, i.e. that is distributed without prior heating treatment through a water heating element. Preferably, such temperature is comprised within the range of 1 C. to 30 C., more preferably, comprised within 4 C. to 20 C.

[0055] The brewing unit according to the present invention is meant to be used in fluid and electrical connection to the base of a beverage preparation machine illustrated in FIG. 1, thus forming a whole functional beverage preparation machine. The brewing unit can be an integral part of the machine (i.e. not removable therefrom without a complex, and possibly destructive operation), or alternatively, said brewing unit can be designed as a detachable part from the beverage machine base. One possible embodiment of such a machine is schematically described hereafter with reference to FIG. 1. Furthermore, in the embodiments described hereafter, it is assumed that the beverage precursor ingredient is contained in a rigid or semi rigid capsule, for instance of the type described in the Applicant's European patent EP 1472156 B1.

[0056] As shown in FIG. 1, the machine 1 comprises a machine body 2, a water reservoir 3 that can be removed from the machine body 2 for refill. The body 2 comprises an on/off push button 4. The machine 1 further comprises an brewing unit 5 that is fixed to the body 2 of the machine. The brewing unit 5 comprises a water temperature selector for hot or cold water taking the form of two buttons 6 (one for selecting a hot beverage, the other for cold), and an opening for insertion of a capsule holder 7. The machine 1 further comprises a cup tray 8, for holding a cup under the brewing unit dispensing outlet. The machine further comprises a control panel 9 for selecting a beverage preparation parameter, typically for instance the volume of beverage to be dispensed. The control panel can comprising a selector wheel as shown in FIG. 1, or alternatively a tactile panel (i.e. a touch screen). The capsule holder 7 is adapted to receive an ingredient capsule 11.

[0057] The capsule holder 7 is represented in FIG. 2, when detached from the rest of the brewing unit. It comprises a cavity part 12 for inserting an ingredient capsule 11 therein before insertion of the capsule holder 7 inside the brewing unit 5 of the machine 1. The capsule holder 7 further comprises a handle 13 which preferably, but not necessarily, protrudes from the boundaries of the machine 1 when the capsule holder is inserted therein as illustrated in FIG. 1. The capsule holder serves to hold the ingredient capsule and maintain the physical integrity of the latter during brewing of a beverage. As an example, as fluid is injected within the capsule during a brewing process, fluid pressure inside the capsule may increase to several bar, which may damage the capsule. By holding the capsule walls, the capsule holder ensures that the capsule walls are not damage by internal pressure increase.

[0058] In the rest of the description, explanations will focus on the brewing unit part of the machine.

[0059] The brewing unit according to the invention comprises an assembly of mechanically linked elements which cooperate to automatically actuate opening and closing of the brewing unit, but also cooperate to automatically select the appropriate fluid circulation from the machine pump towards an ingredient capsule inserted within the capsule holder, according to the selection that is made by the user through the hot/cold selection buttons 6.

[0060] The brewing unit 5 according to the invention is illustrated in FIGS. 3 and 4, in its fully assembled state, with a capsule holder 7 inserted therein. In these FIGS. 3 and 4, the outer casing of the machine is removed so that the constitutive elements of the brewing unit are visible.

[0061] The brewing unit comprises a pair of cavity parts forming together a cavity for receiving an ingredient capsule. In the embodiment described herein and illustrated in FIG. 4, the lower cavity part of the machine is the capsule holder 7. However the lower cavity part could be a cavity able to receive at least a portion of a capsule or other ingredient package, and which is integrated to the rest of the brewing unit, as a non-detachable part, or only partially detachable (i.e. movable or pivotable) part. The upper cavity part 14 illustrated in FIGS. 4 and 5, is movable in translation relative to the capsule holder (which in this particular embodiment is stationery once fully inserted in the dedicated receptacle of the brewing unit), so as to open or close said cavity.

[0062] The brewing unit further comprises injection means for injecting into the capsule a fluid distributed through pipes from two alternative fluid sources located in the machine. The injection means comprise a water injection needle 15. Once injected into the capsule, said fluid mixes with the ingredient contained in the capsule, so as to produce a beverage that is then dispensed out of the capsule into a cup or similar container located below a dispensing opening of the capsule. The first fluid source is water pumped from the water reservoir directly and conducted towards the fluid injection needle 15. The second source of fluid is water pumped from the water reservoir, but which passes through a water heating element (not illustrated) such that heated water is injected into the capsule (or other ingredient package) held in the brewing unit cavity, through the water injection needle 15. The movable upper cavity part is also illustrated in FIG. 6 which is a top perspective view. In this figure, it can be seen that the upper cavity part comprises a water connector 20 for connecting a cold water pipe, and a water connector 21 for connecting a hot water pipe. Both connectors 20 and 21 are in fluid communication with the water injection needle 15.

[0063] As shown in FIG. 7, a screw shaft 18 is attached by its so-called proximal end to the movable cavity part 14. The other end of the screw shaft 18 (i.e. the distal end) is free.

[0064] The brewing unit further comprises a motor 16, illustrated in FIGS. 8, 9 and 10. Said motor has an output shaft 17.

[0065] As shown for instance in FIGS. 6 and 7, the brewing unit according to the invention also comprises a screw nut 22 movable in rotation along a thread path of screw shaft 18 in a translation shaft arrangement. The screw nut 22 is mechanically linked to the motor output shaft 17 such that when said nut 22 is rotated by the motor, it imparts a translation movement to the screw shaft 18, and therefore, to the movable cavity part 14 relative to the rest of the brewing unit. As shown in FIGS. 6 and 7, the screw nut 22 comprises a first catching means which is a protrusion 23 extending from its peripheral edge 24. The function of the first catching means will be described in more detail hereafter.

[0066] The output shaft of the motor and the screw nut are mechanically linked through a gear shaft assembly. As illustrated in FIGS. 8, 9A, 9B, 9C and 10, the gear shaft assembly comprises a motor gear wheel 25 fixed to the motor output shaft 17, and a drive gear wheel mounted onto the screw shaft 18. The drive gear wheel 25 is fixedly attached to the screw nut 22 so that they both rotate around the screw shaft 18 simultaneously. The motor gear wheel 25 is smaller than the screw shaft gear wheel 26. Furthermore, in the embodiment illustrated in FIG. 8, the motor gear wheel 25 and the screw shaft gear wheel 26 are linked by an intermediate speed reduction gear wheel 27 that comprises two bearing of various diameters, so as to achieve a reductor gear between the motor and the screw shaft. The characteristics and dimension ratios in the gear arrangement of the present embodiment are as follows:

[0067] Motor gear to intermediate gear wheel .sup.1/1.6

[0068] Intermediate gear wheel to drive gear wheel=

[0069] The brewing unit also comprises a peristaltic fluid valve 28 for conducting or blocking one or another fluid (e.g. hot/cold water) from the machine towards said injection means through two flexible pipes corresponding to each of the two fluid sources. The peristaltic valve is represented in FIGS. 11 to 14B.

[0070] The peristaltic valve comprises two modules 28A and 28B, each of which is adapted around a corresponding flexible pipe 29A and 29B. Each peristaltic valve module comprises a mobile jaw 30 for pinching the corresponding pipe. In the embodiment represented in the figures, especially in FIGS. 11 to 14B, the peristaltic valve module 28A encloses a portion of the pipe that conducts hot water, whereas the peristaltic valve module 28B encloses a portion of the pipe that conducts cold water. Each module 28A, 28B further comprises: [0071] a closing rocker body 31 for pressing said jaw 30 onto the pipe and closing it, when said closing rocker body 31 is pressed in a direction substantially parallel to the screw shaft 18, and [0072] an opening rocker body 32 for moving said jaw 30 away from said pipe so as to open it, when said opening rocker body 32 is pressed in a direction substantially parallel to the screw shaft 18.

[0073] Furthermore, each module 28A, 28B comprises a spring that forces the closing rocker body 31 in the closing position (i.e. so that the jaw 30 presses onto said tube) when no rocker body is actuated, such that when no pressure is applied to the rocker bodies, the jaw presses onto the corresponding pipe sufficiently to prevent fluid circulation therethrough, if the fluid pressure within said pipe is below a predetermined safety pressure lower than 3 bar, preferably lower than 2 bar.

[0074] The brewing unit according to the invention further comprises a preselector 33.

[0075] The preselector 33 comprises a rigid element pivotable between two angular positions around an axis which is the same as the longitudinal axis of the screw shaft 18. The preselector 33 comprises first and second actuating pins 34A, 34B, each pin extending from the rigid element towards a valve module, as shown for instance in FIGS. 11, 12 and 13. According to this configuration, the peristaltic valve can be set to two positions, as follows.

[0076] In the first position of the preselector 33 illustrated in FIG. 11, the first actuating pin 34A overlaps the opening rocker body 32 of the first module 28A in a plane perpendicular to the screw shaft 18, while simultaneously the second actuating pin 34B overlaps the closing rocker body 31 of the second module 28B in a plane perpendicular to the screw shaft 18. In this position, when the pump of the beverage preparation machine is started, the cold water pipe is closed and the hot water pipe is open such that hot water is conducted from the reservoir 3, through the water heating element and water pipes, towards the water injection needle 15. Such a position of the peristaltic valve is required for preparing hot beverages such as coffee for instance.

[0077] In the second position of the preselector 33 illustrated in FIG. 12, the first actuating pin 34A overlaps the closing rocker body 31 of the first module 28A in a plane perpendicular to the screw shaft 18, while simultaneously the second actuating pin 34B overlaps the opening rocker body 32 of the second module 28B in a plane perpendicular to the screw shaft 18. In this position, when the pump of the beverage preparation machine is started, the hot water pipe is closed and the cold water pipe is open such that cold water is conducted from the reservoir 3, through water pipes, towards the water injection needle 15. Such a position is required for preparing cold beverages. By cold, it is mentioned temperature which is the temperature of the water within the water reservoir of the machine. Generally, such so-called cold water is at room temperature.

[0078] Similarly to the screw nut 22 which comprises a first catching means in the form a protrusion 23 having a generally triangular shape and extending outwardly from the peripheral edge of said nut, the preselector 33 comprises a second catching means which is a spring-mounted protrusion or a flexible tongue 35 extending from the surface of said rigid element so as to be able to catch the screw nut protrusion 23 at a point along the thread path that is distant from the extremities of said path by at least 1/16th of a nut rotation, in order to form a reversible ratchet arrangement. The flexibility of the tongue is adjusted such that the ratchet force is sufficient for pivoting the preselector element between its two angular positions, but insufficient for stopping the rotation of the screw nut further along the screw shaft during its rotation around the screw shaft, when the motor is running.

[0079] In any case, the catch point between the preselector tongue 35 and the protrusion 23 of the screw nut 22, is located at a distance comprised between 1/16th and th of a screw nut rotation, from the proximal extremity (or proximal end) of the screw shaft 18. This allows the screw nut 22 to continue its rotation further after said screw nut has caught the preselector tongue and driven said preselector in rotation to one of its two positions, such that by rotating further, the screw nut can separate (i.e. unhook) easily from the tongue of the preselector, and rotate further so that the movable cavity part can also move further in one or the other direction.

[0080] The preselector element is pivotable between two angular position around an axis parallel to, or coaxial with, the screw shaft longitudinal axis (SL). The two positions of the preselector are distant from one another by pivoting said preselector around its rotation axis of an angle comprised between 3 and 45, preferably an angle comprised between 5 and 20. Advantageously, the rotation axis of the preselector is merged with the longitudinal axis of the screw shaft.

[0081] At the beginning of each and every machine start, in order to ensure that the same valve position is selected (which by default in the preferred embodiment is the hot water position because most of the beverages prepared by consumers are hot beverages), said machine is programmed such that when it is turned on, the motor actuates the brewing unit gears so as to rotate the screw nut in its position where it is closest to the proximal end of the screw shaft (i.e. when the movable cavity is at its uppermost position), as illustrated in FIG. 9A. In this position also illustrated in FIG. 11, the screw nut 22 rotates the preselector 33 in its position where the actuating pins 34A and 34B are aligned to simultaneously: [0082] press onto closing rocker body 31 of the peristaltic valve module mounted on the cold water pipe, to block the flow of cold water towards the injection needle 15, and [0083] press onto the opening rocker body 32 of the peristaltic valve module mounted on the hot water pipe, to allow hot water to circulate.

[0084] As illustrated in FIGS. 8, 9A, 9C and 10, the brewing unit further comprises an encoder wheel 36 and a sensor 37 mechanically linked to the output shaft 17 of the motor 16, for detecting the exact angular position of the screw nut 22 along the screw shaft 18. Such a mechanism allows to finely determine the position of the different movable parts of the brewing unit, in particular the position of the screw nut across the screw shaft. Depending on the position of the screw nut, the state of the fluid valve (closed, selection of hot water, selection of cold/ambient water) is known and controlled by the electronic control board of the beverage preparation machine. The encoder wheel 36 and sensor 37 preferably take the form of an optical encoder, as illustrated in FIG. 10.

[0085] The optical encoder is a light barrier disc with increment teeth. It can be an incremental encoder, but is preferably an absolute encoder that keeps in memory the extreme positions of the movable cavity part of the brewing unit, such that in case of unexpected shutdown of the brewing unit, it will automatically detect the position of the movable cavity part at the next system wake-up, and will actuate the motor to place the brewing unit in open position for a new use, if necessary. By default, the most remote position of the movable cavity part relative to the other cavity part is memorized in the control board of the brewing unit, as well as the position of said movable cavity part in contact to the other cavity part (i.e. in a closed configuration of the brewing unit cavity. Between these two extreme positions of the movable cavity part, the movement of the mechanic is electronically tracked on every position from top till down which closes the brewing unit. As a principle, the optical encoder's disc is made of glass or plastic with transparent and opaque areas. As illustrated in FIG. 8, these areas take the form of teeth disposed on the periphery of the encoder disc. Each tooth blocks the light emitted by a diode of a photo detector, while each gap between adjacent teeth lets light through, which is detected by the light sensor of the photo detector For this purpose, the diode and the light sensor of the photo detector are each disposed on a different side of the encoder disc. In an alternative embodiment, the disc can be covered with a light reflective material, such that light is sensed by the light sensor when a tooth faces said sensor (reflective principle contrary to the transmission principle described above). The light sensor of the photo detector reads the optical pattern that results from the encoder disc's position at any one time, which is translated by a micro-controller or microprocessor into the angular position of the main transmission shaft, that gives a precise indication of all of the position of the elements of the gear mechanism, i.e. the output shaft of the motor, the gear wheels, the main transmission shaft, and therefore precise the position of the movable cavity part of the brewing unit between its closed and its fully open positions. In alternative equivalent embodiments, the optical encoder described above can be replaced by a mechanical, a magnetic, or a capacitive encoder.

[0086] It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be covered by the appended claims.