WO2019135194A1

WO2019135194A1 - Dispensing unit for espresso

Info

Publication number: WO2019135194A1
Application number: PCT/IB2019/050064
Authority: WO
Inventors: Flavio LOT
Original assignee: Gruppo Cimbali S.P.A.
Priority date: 2018-01-04
Filing date: 2019-01-04
Publication date: 2019-07-11
Also published as: EP3735158A1; IT201800000554A1; CN111542248A; AU2019205868A1

Abstract

An espresso dispensing group (MC) comprises a chamber (40) comprising a hot water inlet and a hot water outlet toward an amount of product (P), a plunger (20) adapted to move in a linear direction (X) in the chamber (40) to compress hot water toward the outlet, an operating lever (30) connected to the plunger (20) and manually operable to move the plunger (20) in the chamber (20), an electric actuator (50) which is coupled to the plunger (20) to move it in the chamber (40), an electronic regulator connected to the electric actuator (50) and configured to drive the electric actuator (5) to control the displacement of the plunger (20) in the chamber (40), a position sensor (90) connected to the regulator and configured to generate a position signal representative of the linear position of the plunger (40).

Description

TITLE: "Dispensing unit for espresso"

DESCRIPTION

The present invention relates to a dispensing unit for espresso and an espresso machine equipped with such dispensing unit.

Many machines are known for preparing espresso from coffee grounds, pods, capsules or the like, for example, which pressurize the water required for infusion by using the energy stored in a spring that was previously loaded by a manual action. Typically, the machine comprises a cylindrical chamber for water and a piston that is adapted to slide in the chamber to compress the water toward a dispensing cup containing the coffee grounds. The piston is raised in the chamber by a manual action on a lever. At the same time a spring is compressed in the cylinder and a hole in the wall of the cylinder is opened for receiving hot water. As soon as the the operating lever is released, it returns to the initial position under the action of the spring and the piston moves down. Thus, the piston presses the hot water that has just flown in outside the cylinder toward the portafilter cup.

These prior art piston-operated machines suffer from certain drawbacks.

The first drawback is the risk that, if the lever comes out of hand, it may be violently pushed upwards due to the compression of the spring, and it may often hit the operator. Furthermore, the only force that generates pressure in water is the force generated by the spring. During dispensing, the spring generates a force that decreases from a maximum value (when the piston is raised) to a minimum value (when the piston is lowered). Therefore, dispensing cannot occur with a desired pressure pattern, as suggested by optimal preparation rules. Indeed, different coffee mixtures are known to required different pressure profiles for best results. Finally, a great muscular effort is required to lower the lever and overcome the spring force.

The main object of the invention is to improve this prior art. Another object is to provide a dispensing unit that is not dangerous for the operator, that allows dispensing with a desired pressure pattern, and requires a small muscular effort.

A first aspect of the invention relates to an espresso dispensing unit, the dispensing unit comprising:

a chamber comprising a hot water inlet and a hot water outlet toward a given amount of powdered infusion product,

a plunger that can be moved (e.g. by translation) in the chamber to push the hot water toward the outlet,

an optional lever connected to the plunger for moving it (e.g. by translation);

an electric actuator which is coupled to the plunger to move it in the chamber.

In a second aspect the invention relates to a machine for making espresso from a powdered product by infusion, comprising the dispensing unit according to one or each of its variants. Preferably, the electric actuator is a rotary motor; and/or the electric actuator is a fluid compressor, e.g. air or a liquid; and/or the electric actuator is a linear electric actuator, and/or the electric actuator is coupled to the plunger to linearly move it in the chamber.

Preferably, the plunger can be linearly moved by translation in the chamber to both open said inlet and press the hot water toward the outlet. Otherwise, the plunger is adapted to be generally moved inside the chamber, e.g. by rotation, to compress the hot water toward the outlet.

Preferably, the lever is connected to the plunger. When there is no lever, the size of the dispensing unit is reduced, and the structure of the unit itself is simplified, without affecting the quality of the beverage that is being dispensed. The presence of the lever is advantageous, for example, to simplify the actuator, and allow the operator to only lift the piston, whereas the actuator actuates the piston in the return step, i.e. during water compression. Preferably, the hot water inlet is situated on the side walls of the chamber and the hot water outlet is situated on the bottom of the chamber.

In one variant, the translation or displacement of the plunger in the chamber is controlled by programming its motion dynamics by means of the actuator, to thereby program pressure patterns for the hot water conveyed toward the product to obtain the infusion therewith. In particular, the translation or displacement of the plunger in the chamber is controlled via an electronic regulator, namely of programmable type, which is configured to drive the actuator. Thus, by programming the regulator with the motion dynamics imposed to the actuator by the piston, pressure patterns may be programmed for the hot water delivered to the product to obtain the infusion therewith.

In one variant, the translation or displacement of the plunger in the chamber is regulated by means of a position sensor, e.g. of electronic type, e.g located on the lever and/or on the plunger The position sensor may be also implemented by mechanical means, e.g. with cam mechanisms or pantographs. By detecting the position of the plunger in the chamber and/or the positions of the lever, the regulator is configured to determine, for example, the actuator on and off times, such that the operator will be able to operate the unit with no additional control, as if the lever were, like in the prior art as described hereinbefore, the dispensing control member. If there is no lever, in one variant, the actuator on and off times are determined via a dedicated user interface^ g a button or an electric switch.

Preferably the chamber has a cylindrical shape.

In all the above aspects of the invention, the plunger is preferably slidably mounted in the chamber to compress water toward a dispensing cup that contains the powdered product. In all the above aspects of the invention, a spring is preferably provided, which is mounted to counteract the downward movement of the operating lever (if any) and to bring the lever back to the start position. In one variant, the plunger is coupled to the actuator via a gear or a pressurized fluid.

One variant of the dispensing unit comprises an electronic regulator, namely of programmable type for controlling the translation or displacement of the plunger in the chamber.

One variant of the dispensing unit comprises a position sensor, e.g. of electronic type is included, e.g. placed on the lever and/or the plunger and connected to the regulator, to control the translation of displacement of the plunger in the chamber. Namely, the regulator is configured, for example, to determine the actuator on and off times according to the signal received by the sensor. The sensor may be, for example, a load cell, an optical encoder, a potentiometer or a simple open/close electric switch (such as a microswitch).

If there is no lever, one variant of the dispensing unit comprises a dedicated user interface^ g a button or an electric switch, for determining the actuator on and off times. In one variant, the electronic regulator is configured to actuate the translation or displacement of the plunger in one direction only, i.e. the direction of water compression toward the infusion product. In this case the coupling between the plunger and the actuator is designed to be idle or impeded during translation or displacement of the plunger in the opposite direction, i.e. when the plunger is translated or displaced to bring water back into the chamber. This occurs when the operator pulls the lever. Thus, the actuator only operates when water is compressed toward the outlet of the chamber by the plunger. In yet another variant, the electronic regulator is configured to actuate the translation or displacement of the plunger in both directions (e.g. translation directions), i.e. either the water compression direction toward the infusion product or the direction of translation or displacement of the plunger to bring water back into the chamber. Thus, the actuator operates during the two oppositely directed displacements of the plunger and constantly assists the operator in his/her movement if the lever is provided. In one variant of the dispensing unit the plunger is coupled to the actuator via a gear. In particular, the plunger comprises a rack engaged with a gear wheel that is rotatably connected to the actuator. In another type of coupling, for example, a screw is rotatably connected to the actuator and a corresponding nut is coupled with the screw to be linearly translated, or vice versa. This nut and screw coupling allows, for example, a rotary electric motor to be placed coaxial with or parallel to the axis of translation or displacement of the plunger, which entails an optimized reduction of the overall dimensions (the same applies to a linear actuator). This arrangement is particularly advantageous when no lever is provided.

In one variant of the dispensing unit, the plunger is coupled to the actuator via a pressurized fluid. Namely, the actuator, which is for example a linear actuator, is equipped with a plunger to compress a fluid in a fluid reservoir. The fluid reservoir communicates with one or two pipes for conveying the pressurized fluid toward the plunger of the chamber, such that it may be translated or displaced back and/or forth. The plunger is moved in the chamber by the thrust of the pressurized fluid. This variant is advantageous because the fluid reservoir can be detached from the dispensing unit and stored in a less dimension- critical location, whereas the dispensing unit becomes very compact, especially it no longer comprises the actuator.

The position of the position sensor may vary from what has been described above. For example, the position sensor may be placed on the casing of the dispensing unit or in the chamber.

The advantages of the invention will be more apparent from the following description of a preferred embodiment of a dispensing unit, with reference to the attached drawing in which - Fig. 1 shows a side view of a dispensing unit;

- Fig. 2 shows a front view of the dispensing unit, - Fig. 3 shows a vertical sectional view of the dispensing unit as taken along the plane III- III;

- Fig. 4 shows a vertical sectional view of the dispensing unit as taken along the plane III- III according to a second operating configuration;

- Fig. 5 shows a diagram of another dispensing unit;

- Fig. 6 shows another diagram of a dispensing unit.

Equal numbers designate equal or conceptually similar parts throughout the figures. In general terms such as vertical, horizontal, upper, etc. are related to the normal conditions of use.

A MC dispenser comprises a metal body 10 and an operating lever 30 which is hinged thereto at the top. The lever 30 is manually operable to lift a stem 22 that is mounted in the body 10.

The stem 22 is connected to a plunger 20 that can be translated back and forth along an axis X, vertically oriented during operation, in a chamber 40 formed in the bottom and into the body 10.

The back-and-forth movement of the plunger 20 exposes the opening of a hot water pipe 64 originating from a boiler, not shown, on the walls of the chamber 40. The hot water is compressed by the piston 20 and conveyed outside the chamber 40 toward a powdered product panel P, where the hot water will cause infusion thereof and hence will produce the beverage. The hot water supply system, synchronized with the movement of the lever 30, may be of any known type and is not critical.

Namely, the lever 30 is connected to the stem 22 via a pin 32 that slidably arranged into a slot 24 at the end of the stem 22.

The slot 24 comprises a tooth 28 that abuts a lever 60 pivoted on the body 10. During translation of the stem 22, the tooth may displace the lever 60, which is connected to the stem 62 of a valve that regulates the flow of hot water flowing through the pipe 64. Without loss of generality, the flow of hot water that is designed to flow into the chamber 40 when the plunger 20 has been lifted, may be also controlled in different manners.

An optional spring 70 pushes the piston 20 downwards, i.e. toward the panel P.

A toothing or longitudinal rack 26, extending along the axis X, is provided on the stem 22, and is designed to mesh with a gearwheel 52 that is connected to the output shaft of a rotary electric motor 50. The linear position of the stem 22 is detected by a sensor 90 connected to an electronic controller (not shown) that controls the motor 50. The structure and/or position of the sensor 90 are not critical and may be of various types, e.g. a proximity sensor, an optical encoder, a Hall effect sensor or a simple ON/OFF electric switch, for detecting one or both opposite limit stops of the stem 22. The signal generated by the sensor 90, the electronic controller that controls the motor 50, and the mechanical coupling between the motor 50 and the stem 22 form a positional feedback control.

The MC dispenser operates as follows.

In the rest position the operating lever 30 is lifted, as shown in Fig. 3.

In this position the plunger 20 occupies the chamber 40 and blocks the opening of the pipe 64. The tooth 28 keeps the lever 60 in a position in which the stem 62 blocks the flow of hot water through the pipe 64.

In order to dispense the beverage the operator pulls the operating lever 30, as shown in Fig. 4. Then the pin 32 slides within the slot 24 and lifts, by a cam movement, the end of the stem 22 and the plunger 20. In this position the plunger 20 has raised along the axis A and has left the chamber 40, thereby clearing the opening of the pipe 64. The tooth 28 has also moved and has moved the lever 60 to a position in which the stem 62 allows the hot water to flow through the pipe 64 to fill the chamber 40. The toothing or rack 26 has also raised with the stem 22, but now the gearwheel 52 is idle (the electric motor 50 is switched off by the controller). Optionally, in this step the controller may use the sensor 90 to detect the displacement of the stem 22 and control the electric motor 50 to rotate the gearwheel 52 to cause the movement of the lever 30.

Once the operating lever 30 has reached its limit stop position, the operator releases it. In this position, the plunger 20 has raised to the top along the axis X and has reached a limit stop position, as detected by the sensor 90. Now the controller uses the sensor 90 to detect the limit stop position of the stem 22 and controls the electric motor 50 to rotate the gearwheel 52 to move the stem 22 in the opposite direction. The rotation of the gearwheel 52 lowers the stem 22 and the plunger 20 in the chamber 40, and the hot water therein is compressed toward the panel P. Meanwhile, the lever 30 moves back to the start position, as shown in Fig. 3.

Once the plunger 20 has moved down to the bottom limit stop position, as detected by the sensor 90, the controller controls the stop of the electric motor 50 to stop the gearwheel 52. The cycle may be started again for a new dispensing operation.

Fig. 5 shows a diagram of a variant of a dispensing unit. Unlike the previous embodiment, the electric motor 50 is coaxial with the stem 22, and there is no lever. The shaft of the motor 50 comprises a screw 80 cooperating with a nut 82 that is rigidly joined to the stem 22. The rotation of the shaft of the motor 50 causes the kinematic pair formed by the screw 80 and the nut 82 to be lengthened and shortened, whereby the stem 22 will reciprocate along the axis X.

Fig. 6 shows another diagram of a variant of a dispensing unit. The plunger 20 is coupled to an external linear actuator 84 via a pressurized fluid. The actuator 84 comprises a plunger 86 for compressing a fluid in a fluid reservoir 88. One or two pipes 94 are designed to carry the pressurized fluid that flows out of the reservoir 88 toward the plunger 20 of the chamber 40, where the fluid pressure is utilized to move the plunger 20 back and/or forth. For this purpose, the plunger 20 may be coupled, for example, to another plunger 98 which is in turn able to move in another tight chamber 99. The plunger 98 is linearly moved along the axis X in the tight chamber 99 by the pressurized fluid that flows out of the reservoir 88 through the pipes 94.

With two pipes 94 carrying fluid toward opposite sides of the plunger 98, the plunger 98 may be moved in two opposite directions. With one pipe 94, the plunger 98 may be moved in one direction only, unless a directional control valve is used to selectively convey the pressurized fluid to opposite sides of the plunger 98.

In one variant, the pipes 94 directly reach the plunger 20, to move it in at least one direction along the axis X.

The variants of Figs. 5 and 6 provide a very compact dispensing unit. Namely, the actuator 84 and/or the pipes 94 may be external to and separated from the dispensing unit and/or may supply pressurized fluid to more than one dispensing unit.

In Figures 1 and 2, the position of the motor 50 is not critical, as the motor may be installed, for example, in any angular position around the lever 30.

Also in the variant of Figs. 5 and 6 the position of the motor 50 or the chamber 99 is not strictly binding, as they may be installed, for example, offset from the axis X.

The units as disclosed herein may be integrated in a larger dispensing machine is larger and/or with additional dispensing units, not shown.

Claims

1. A dispensing unit (MC) for espresso obtained from powdered infusion product, the dispensing unit comprising:

- a chamber (40) comprising a hot water inlet and a hot water outlet towards a quantity of product (P),

- a plunger (20) movable in a linear direction (X) inside the chamber (40) to push the hot water towards the outlet,

- an operating lever (30) connected to the plunger (20) and manually operable to move the plunger (20) into the chamber (20),

- an electric actuator (50) coupled to the plunger (20) to move it in the chamber (40).

- an electronic regulator connected to the electric actuator (50) and configured to drive the electric actuator (5) to control the displacement of the plunger (20) in the chamber (40),

- a position sensor (90) connected to the regulator and configured to generate a position signal representative of the linear position of the plunger (40),

characterized in that the electronic regulator is configured to turn the electric actuator (50) on and off in response to the position signal generated by the position sensor (90) so as to to move the plunger (20) in the chamber (40) in a first direction corresponding to the direction in which the plunger (20) moves to compress the water towards the infusion product.

2. A dispensing unit (MC) as claimed in claim 1, wherein the position sensor (90) is placed on the operating lever (30).

3. A dispensing unit (MC) as claimed in claim 1, wherein the position sensor (90) is placed on the plunger (20).

4. A dispensing unit (MC) as claimed in any of claims 1 to 3, wherein the electronic regulator is configured to turn the electric actuator (50) on and off in response to the position signal generated by the position sensor (90) so as to move the plunger (20) in the chamber (40) also in a second direction, opposite to the first direction and corresponding to the direction in which the piston moves to draw water into the chamber (40), in response to the position signal generated by the position sensor (90).

5. A dispensing unit (1) as claimed in any of claims 1 to 4, wherein:

- a stem (20) is connected at an end to the plunger (20) and has a slot (24) at an opposite end,

- the operating lever (30) is connected to the stem (22) via a pin (32) slidably arranged into the slot (24).

6. A dispensing unit (MC) as claimed in claim 5, wherein the position sensor (90) is placed on the stem (22) to detect the linear position of the stem (22).

7. A dispensing unit (1) as claimed in any of claims 1 to 6, wherein:

- the electric actuator is a linear electric actuator (84) and comprises a stem that ends with a plunger (86) configured to compress a fluid in a fluid reservoir (88),

- the fluid reservoir (88) comprises at least one conduit (94) in fluid communication with the plunger (20) moving in the chamber (40) such that the pressurized fluid that flows out of the fluid reservoir (88) causes the translation of the plunger (20) in the chamber (40).

8. A dispensing unit (MC) as claimed in claim 7, wherein: - the plunger (20) of the chamber (40) is connected to a second plunger (98) which is movable in a sealed chamber (99),

- the pressurized fluid that flows out of the fluid reservoir (88) causes the translation of the second plunger (98) in the sealed chamber (99).

9. A dispensing unit (MC) as claimed in claim 7 or 8, wherein:

- the fluid reservoir (88) comprises two conduits (94) to thereby move the plunger (20) in the chamber (40) in two opposite directions.

10. A dispensing unit (1) as claimed in any of claims 7 to 9, wherein:

- the electric linear actuator (84) and the fluid reservoir (88) are configured to be connected to and disconnected from the dispensing unit (MC).