Modular brewing unit for a coffee machine

Abstract

The invention relates to a modular brewing unit for a coffee machine, comprising a brewing part and a drive part, which are arranged parallel one beside the other in a common frame, wherein the brewing part, arranged concentrically along a common first axis, has an upper piston, a lower piston and, between the two pistons, a brewing cylinder with a cylindrical bore for accommodating the two pistons, a brewing chamber being formed in the process, and wherein the drive part comprises a spindle which extends along a drive axis, parallel to the first axis, is mounted in the frame such that it can be rotated about said drive axis and is in engagement with the brewing cylinder and the lower piston such that, during a brewing cycle, upon rotation of the spindle, the brewing cylinder and the lower piston are displaced along the first axis relative to the upper piston, which is fixed in the frame. Different brewing units are realized in a simplified manner in that the drive part can be combined with brewing parts of different designs in order to provide for different brewing conditions.

Claims

1. Modular brewing unit for a coffee machine, comprising multiple differently constructed brewing parts and a driving part, wherein one brewing part and the driving part are arranged parallel beside each other in a common frame, wherein the brewing part has, arranged concentrically along a common first axis, an upper piston, a lower piston, and a brewing cylinder between the two pistons, having a cylindrical bore to accommodate the two pistons, forming a brewing chamber, and wherein the driving part comprises a spindle that extends along a drive axis parallel to the first axis, is mounted in the frame so as to be rotatable about said drive axis, and is in engagement with the brewing cylinder and the lower piston such that, during a brewing cycle, when the spindle is rotated the brewing cylinder and the lower piston are displaced along the first axis relative to the upper piston which is mounted in fixed manner in the frame, different brewing conditions can be formed by selectively combining the driving part with the differently constructed brewing parts, wherein the brewed coffee is discharged through the upper piston, and that the outlet behaviour in the upper piston can be altered to create different brewing conditions in the brewing part by positioning replaceable inserts in the upper piston.

2. The modular brewing unit according to claim 1, wherein the upper piston has a central passthrough for the outlet, and the replaceable inserts can be inserted, particularly screwed, in the passthrough to create a seal.

3. The modular brewing unit according to claim 1, wherein the replaceable inserts each have a cylindrical body with a concentric bore to allow the brewed coffee to pass through.

4. The modular brewing unit according to claim 3, wherein the replaceable inserts have an external thread section, a transition to a tubular spout at one end, and are furnished with an external seal at the other end.

5. The modular brewing unit according to claim 3, wherein the replaceable inserts are equipped with means for influencing the flow through the bore.

6. The modular brewing unit according to claim 5, wherein the means for influencing the flow through the bore comprise a replaceable baffle.

7. The modular brewing unit according to claim 5, wherein the means for influencing the flow through the bore comprise a non-return valve.

8. Modular brewing unit for a coffee machine, comprising multiple differently constructed brewing parts and a driving part, wherein one brewing part and the driving part are arranged parallel beside each other in a common frame, wherein the brewing part has, arranged concentrically along a common first axis, an upper piston, a lower piston, and a brewing cylinder between the two pistons, having a cylindrical bore to accommodate the two pistons, forming a brewing chamber, and wherein the driving part comprises a spindle that extends along a drive axis parallel to the first axis, is mounted in the frame so as to be rotatable about said drive axis, and is in engagement with the brewing cylinder and the lower piston such that, during a brewing cycle, when the spindle is rotated the brewing cylinder and the lower piston are displaced along the first axis relative to the upper piston which is mounted in fixed manner in the frame, wherein different brewing conditions can be formed by selectively combining the driving part with the differently constructed brewing parts, wherein the differently constructed brewing parts are designed to accommodate different quantities of coffee powder per brewing cycle and the differently constructed brewing parts differ in respect of the internal diameter of the brewing chamber, and that the outer diameters of the upper and lower pistons are adapted to the internal diameter of the brewing chamber.

Description

BRIEF EXPLANATION OF THE FIGURES

(1) In the following, the invention will be explained in greater detail with reference to embodiments and in conjunction with the drawing. In the drawing:

(2) FIG. 1 shows a lengthwise cross section through a brewing unit such as is known for example from document WO 2009118246 A1;

(3) FIG. 2 shows a lengthwise cross section through a brewing unit in which according to an embodiment of the invention the brewing part is configured for a larger quantity of coffee powder (e.g., 30 g instead of 16 g) but the driving part remains the same;

(4) FIG. 3 shows a side view of the brewing unit of FIG. 2;

(5) FIG. 4 shows a front view of the brewing unit of FIG. 2;

(6) FIG. 5 shows an enlarged detail of the upper piston from the brewing unit of FIG. 2 with a first replaceable insert having a fitted baffle;

(7) FIG. 6 shows an enlarged detail of the upper piston from the brewing unit of FIG. 2 with a second replaceable insert without flowthrough limitation;

(8) FIG. 7 in three different subfigures (a) to (c), shows three different variants of the replaceable insert for the upper piston; and

(9) FIG. 8 in several subfigures (a) to (c), shows an advantageous configuration of the brewing cylinders, in which the guide rails necessary for guiding the brewing cylinder are designed to be folded up to the side (FIG. 8b).

WAYS TO REALISE THE INVENTION

(10) The modular concept of the present invention provides that in if there is a change in the brewing conditions, for example if the basic quantity of coffee powder used for each brewing cycle is changed, driving part 10a of brewing unit is left unchanged, and the necessary design changes are only made to the brewing part. In this way, a family of similar brewing units can be derived from a basic design for the brewing unit quickly and inexpensively, in which all of the members have the same driving part 10a, but differ in the configuration of the brewing part.

(11) In FIG. 2, an embodiment of such a derived brewing unit 10 (from the brewing unit of FIG. 1) is shown from the same point of view as brewing unit 10 of FIG. 1. Identical parts are also designated with the same reference signs. By comparing the two directly, it is immediately apparent that the frame 11, spindle 18, the bearing for spindle 18 in the frame with the bearing pins and bearing rings 22, 23, and the detent device 28, 28 are practically identicalapart from the minor difference in that the bearing element 24 in FIG. 1 is arranged on upper bearing ring 22, while in FIG. 2 it is arranged on lower bearing ring 23.

(12) The changes in brewing part 10b of FIG. 2 compared to FIG. 1 relate firstly to the basic quantity of coffee powder used per brewing cycle. In FIG. 1, a brewing cylinder 14 with a cylindrical bore 15 having internal diameter d1 is used, which diameter combines with the two pistons 12 and 13 to form a brewing chamber 16 that is designed for a basic quantity of 16 g coffee powder. Of course, the quantity of coffee powder can be altered and adjusted within a certain range starting from the basic quantity without altering or impairing the optimised compressing and brewing operation too much.

(13) In contrast, the brewing cylinder 14 used in FIG. 2 has a cylindrical bore 15 with internal diameter d2 which is considerably larger than d1 and when combined with the two similarly larger pistons 12 and 13 creates a brewing chamber 16 that is designed for a basic quantity of 30 g of coffee powder. In order for the larger lower piston 13 to be able to interact smoothly with the practically identical detent device 28 in the manner described in the introduction, a corresponding adapter ring 53 is provided inside lower piston 13.

(14) Since the larger brewing cylinder 14 in the filling position shown in FIG. 2 extends axially farther upwards than in the example of FIG. 1, swivelable funnel 27 must also be changed and adapted with respect to FIG. 1, so that a collision is avoided when the brewing cylinder is raised. For this purpose, the swivelable funnel 27 which is pivotable about swivel axis (FIG. 3) against the spring force of two torsion springs (39a, b in FIG. 4) is no longer constructed as a straight funnel with only one incline, but instead is slightly shortened and has an inward curvature, which in this case is created by two consecutively arranged funnel sections 27a and 27b with progressively less incline. The incline of the upper funnel section 27a is equivalent to the inclination of funnels 27 in FIG. 1. According to FIG. 3, a guide element 37 for swiveling is mounted on funnel 27, and moves along a guide arm 38 of the wiper 29 that is pivotable about swivel axis 36 when brewing cylinder 14 is raised (see FIG. 3). Upper funnel 26 remains practically unchanged.

(15) Because of the larger internal diameter d2 of brewing cylinder 14, the chute 54 for the coffee powder cake that is scraped off by wiper 29 must be shifted farther out, but this can be done without making any structural changes to frame 11.

(16) However, another possible change to brewing part 10b also concerns the internal construction of upper piston 12, by which the brewed coffee is guided from the brewing chamber 16 through a corresponding strainer 34 to the coffee machine outlet. Since the brewing operation requires an optimal distribution and passage of the brewing water, which is introduced through a brewing water port on the side (40 in FIG. 4), through the compressed coffee powder enclosed in brewing chamber 16, before which the powder must be moistened as evenly as possible, the passage of the brewed coffee through upper piston 12 becomes particularly important.

(17) In order to be able to make changes in modular manner here, an axial passthrough 32 is conformed in the centre of upper piston 12, into which replaceable inserts 33 (33a, b in FIGS. 5 and 6; 33a-c in FIG. 7) are inserted, particularly screwed to form a seal. Enlarged cross sections of two such inserts 33a and 33b are shown in FIGS. 5 and 6. FIG. 7 shows inserts 33a and 33b as separate parts (FIGS. 7a and b), and a further insert 33c (FIG. 7c).

(18) The screwed insert 33a in FIG. 5, which is shown in a longitudinal cross section and in a 3-D representation in FIG. 7a, comprises an elongated cylindrical body with a central bore 45. On one end, a tubular spout 42 is formed on body 41, on which the outlet tube leading to the coffee machine outlet is mounted. A seal in the form of an o-ring is provided in an annular groove on the outside of the other end, sealing off the insert 33a in passthrough 32. On this end also, a baffle 46 having a central baffle opening 46a is inserted, e.g., screwed into body 41 for the purpose of sealing. The baffle reduces the flow rate enormously, and so helps to improve distribution and a lengthen the residence time of the brewing water in brewing chamber 16, thus influencing the brewing result. A thread section corresponding to a matching internal thread in passthrough 32 is conformed on the outside before the tubular spout 42 to enable insert 33a to be screwed on.

(19) A further exemplary insert 33b according to FIGS. 6 and 7b has a design that is largely identical to insert 33a, but is not equipped with a baffle. This allows drastically higher flow rates, which in turn also results in changes to the brewing behaviour and result.

(20) A third exemplary insert 33c according to FIG. 7c is conformed on the lower end as a non-return valve 47. A valve body 49 is pressed against a screwed-in valve seat 50 in sealing manner against the flow direction by a spring 48. If the pressure in the brewing chamber 16 rises, non-return valve 47 opens progressively to let the brewed coffee through to the outlet.

(21) This results in a brewing characteristic that may be influenced and optimised according to the choice of spring 48, but also the passthrough cross section of the valve seat 50.

(22) These inserts 33a-c can be fitted and replaced as desired to adapt the brewing part functionally to certain requirements. With these inserts and the replaceable pistons and brewing cylinders in the brewing part, a modular kit is provided for a reliable brewing unit that enables changes to be made to the brewing conditions inexpensively while using a common driving part. But the replaceable inserts may also be used advantageously in brewing units of the kind shown in FIG. 1, without having to make any other changes to the brewing part.

(23) A further simplification may also be applied to brewing cylinder 14 as shown in FIG. 8. In order to be able to move brewing cylinder 14 in the axial direction with spindle 18, brewing cylinder 14 must be guided in frame 11. For this purpose, guide rails 52a, b are arranged on the side of the threaded part 17a of dog 17, which is furnished with a corresponding trapezoidal thread 19 (FIG. 8c), with which the brewing cylinder 14 is guided in corresponding grooves in the frame. These guide rails 52a, b, which were formerly fastened to threaded part 17a with metal screws, are now connected to the side of threaded part 17a by means of a snap locking mechanism.

(24) To realise the snap-fit function, as shown in FIG. 8a cutouts 55a, b are provided at the top and bottom on the opposite sides of threaded part 17a, and into which the guide rail 52 or 52a, b may be inserted using corresponding snap catches 56a, b (FIG. 8b). In order to retain the guide rails 52 or 52a, b, pillar-like first retaining elements 57a, b are conformed at the top and bottom on the sides of threaded part 17a (FIG. 8a), against which guide rails 52 or 52a, b abut with corresponding second guide elements (58a, b) (FIG. 8b) and along which they slide when are snapped into place.

(25) The snap-locked guide elements 52 or 52a, b make it simpler to reconfigure the modular brewing unit further, but they may also be used advantageously on conventional brewing units.

LIST OF REFERENCE SIGNS

(26) 10,10 Brewing unit 10a Driving part 10b, 10b Brewing part 11 Frame 12,12 Upper piston 13,13 Lower piston 14,14 Brewing cylinder 15,15 Cylindrical bore 16,16 Brewing chamber 17,17 Dog 17a Threaded part 18 Spindle 19,19 Trapezoidal thread 20,21 Bearing pin 22,23 Bearing ring 24 Bearing element 25 Electric motor 26,26 Funnel 27,27 Swivelable funnel 27a, b Funnel section 28 Detent device 29,29 Wiper 30 Support plate 31 Drive axis (spindle) 32 Passthrough 33,33a-c Insert (screwed) 34 Strainer 35,36 Swivel axis 37 Guide element 38 Swing arm 39,39a,b Torsion spring 40 Brewing water port 41 Body 42 Tubular spout 43 Thread section 44 Gasket 45 Bore 46 Baffle insert 46a Baffle aperture 47 Non-return valve 48 Spring 49 Valve body 50 Valve seat 51 Axis (brewing part) 52a,b Guide rail 53 Adapter ring 54,54 Chute 55a,b Cutout 56a,b Snap catches 57a,b Guide element 58a,b Guide element d1,d2 Internal diameter (brewing chamber)