In order to obtain the best coffee beverage, it is generally considered by experts that the finely ground coffee grains shall be in contact with water at 94°C for four minutes. This means that the grains shall not be mixed with water until the latter is at a temperature of 92 - 96°C. The coffee grounds shall then be removed from the brew, i.e. the coffee beverage, and the temperature lowered to a holding temperature of about 80 - 85°C.

If the brewing temperature is too low, not all the aromatic substances contributing to the good taste of the coffee beverage are extracted. If the brewing temperature is too high the beverage will be sharp and bitter. Incorrect treatment of the coffee grains is also uneconomical.

Most coffee percolators on the market heat the water to boiling point and then let it drop down into a filtering funnel contai¬ ning the coffee grains. The grains in the funnel are not stirred and there is a tendency for the grains to form lumps. The aromatic substance extraction efficiency is poor. The extraction time and the holding temperature vary in this known percolating method. It is estimated that about 20% of the coffee content can not be extracted by this method, and consequently 20% of the coffee import would be thrown away if this were the only method used, which is a very great waste.

Another type of percolator is one where the water is boiled in a lower vessel and rises through a central tube to an upper vessel containing coffee grains. When all the water has risen into the upper vessel, energy supply to the lower vessel is broken off and this vessel cools, thus reducing the pressure in it. This results in the liquid in the upper vessel being drawn down into the lower one through a filter. The coffee grounds remain in the upper vessel. The drawback with this type is also that there is poor temperature and time control.

A third variation is a method used especially in restaurants, where the water is heated in a serving beaker, and coffee grains

are added to the water and stirred for four minutes. A strainer, sealed against the beaker wall, is then pressed down through the brew, whereat the coffee grounds are separated. With careful procedure, this method provides a very good coffee beverage. However, it is troublesome and needs attendance to obtain good results.

The espresso method is most usual for restaurants. Boiling water is forced through an amount of coffee grains suited to one cup of the coffee beverage. The water is under pressure and passes through the grains in a short time. The procedure is simple to carry out, but time and temperature control are unsatisfactory here as well.

The object of the present invention is to achieve an apparatus for making beverages, e.g. a coffee beverage, that permits brewing at a desired, pre-determined temperature for a pre¬ determined time. For coffee brewing, the first temperature shall be in the range 92 - 96°C, preferably 94°C and the time is preferably four minutes.

The invention also has the object of achieving an apparatus for making beverages where, during the brewing phase, the container holding the coffee grains or their counterpart is moved up and down in the liquid with small movements, so that the grains or the like are put in motion by the water, such as to inhibit the formation of lumps. This increases the extraction efficiency of the aromatic substances. The water is also stirred by the movement of the container, and this contributes to giving the entire water volume a uniform temperature. Layers of water at different temperatures are avoided.

The inventive apparatus shall also permit putting the liquid into motion during its heating-up phase to the pre-determined first temperature, by moving the heating means up and down in the liquid with small movements, so that the entire water volume is given a uniform temperature.

The inventive apparatus shall be easy to operate, and the above- mentioned temperature and time control shall be automated with the aid of a programming means.

The features characterising the invention are apparent from the accompanying claim 1. It shall also be possible to prepare other brewable beverages in the inventive apparatus. Since such beverages usually require other preparation temperatures and times, there can be, in accordance with an embodiment of the invention, special setting knobs or the like for selecting preparation temperatures and times.

Different embodiments of the invention will now be described in connection with the drawings, where

Figures 1-7 illustrate an apparatus in accordance with the invention in side view and in a plurality of stages typical of the use of a coffee percola¬ tor, namely:

Figure 1 The apparatus at the initial stage.

Figure 2 The apparatus at a stage allowing filling water in a brewing vessel.

Figure 3 Filling coffee grains during simultaneous hea¬ ting.

Figure 4 Waiting stage, while the water is being heated to the desired temperature.

Figure 5 The actual brewing.

Figure 6 Temperature holding after termination of ^" bre¬ wing.

Figure 7 The stage where the vessel is taken from the

apparatus for serving a coffee beverage.

Figure 8 illustrates the apparatus of Figure 2, but with parts of the stand removed to reveal the driving means of the apparatus.

Figure 9 is a view corresponding to the one in Figure 8, although illustrating the position of the dri¬ ving means where the apparatus is at another stage, e.g. the waiting stage of Figure 4.

Figure 10 is a view corresponding to the one in Figure 8, although with the driving means in a position corresponding to the brewing stage to Figure 5.

Figs 11,12 schematically illustrate other embodiments of the invention, where the driving means comprises bimetal springs, and

Figure 13 schematically illustrates another embodiment of the coffee grains container.

In figures 1 - 7, the inventive apparatus is illustrated in a plurality of different stages in a typical coffee brewing and coffee beverage serving sequence. The inventive apparatus includes a coffee vessel or jug 10, stand 11, a plurality of covers 12 mounted on the stand and on the inside of which are arranged the driving means and electronic unit of the apparatus, first and second arms 14 and 13 respectively each having one end pivotably mounted on the stand there being a holder 15 removably attached to the other end of the first arm 14 for carrying a granulated coffee container 16 in the form of a fine-mesh net of stainless steel integrated with the holder 15. The container is provided with a lid 17. At the free end of the second arm 13 there is a heating means 18. This means consists of an immersion heater of about 1,5 kW capacity. There is a temperature sensor 50 associated with the immersion heater, preferably on the inside

of its lower end. On the stand there are also two operating buttons 19, 20 for starting different sequences of the operative stages. The button 19 is marked ON - OFF and the button 20 WARM (temperature holding).

It will be seen from figures 8 - 10 that the apparatus includes a motor 22, on the output shaft of which there is fixed a pinion 23. The pinion 23 meshes with a toothed segment disposed along a portion of the circumference of a disc 25, which is rotatably mounted on the stand. The disc carries first 26 and second 27 axially directed pins disposed such that the pin 26 is radially just on the inside of the toothed segment 24, and the pin 27 is radially on the inside of the pin 26, at an angular distance of about 120°. The first pin 26 coacts with two cam surfaces 28 and 29 on the second arm 13, and the second pin 27 coacts with two cam surfaces 30 and 31 on the first arm 14.

A program means 32 (see Figure 1) is arranged behind one of the covers 12, and contains an unillustrated logical circuit, e.g. a microprocessor, as well as drive electronics to motor and heater. The heat sensitive element of the thermostat consists of the mentioned temperature sensor 50 arranged in the heating means 18. The microprocessor of the program means controls the motor, and consequently the movements of the first and second arms, power supply to the heating means, the time during which the granulated coffee container is immersed in the water and the water temperature.

Figure 1 illustrates the initial stage. The two arms are in the positions shown and the heating means is not in circuit.

Figure 2 illustrates the water filling stage, and the associated operations: ON/OFF button 19 is depressed, causing a lamp in it to illuminate and the motor to raise arms 14, 13, to the illustrated position, whereon the lamp is extinguished. The coffee jug has been removed (as illustrated) for filling.

Figure 3 illustrates the stage for water heating and coffee grains dosing and the associated operations: The filled coffee jug is placed in the stand and button 19 is depressed, its lamp illuminates, arms 14, 13 move automatically under motor drive, the second arm 13 with heating means 18 and temperature sensor 50 is moved to a lower position, the heating means is supplied with power for heating the water, the first arm 14 stops in an intermediate position (the dosing position). The holder 15 with container 16 and lid 17 is now removed from the first arm and the container is dosed with a suitable amount of coffee grains, while the water continues to be heated.

Figure 4 illustrates a waiting stage and the associated opera¬ tions: The coffee container, which has been dosed in the previous stage, is now waiting for the water temperature to rise. The button 19 is still illuminated.

Figure 5 illustrates the brewing stage and the associated operations: The water temperature is held at 94°C, to which it has now risen, the program means 32 activates the motor 22 for lowering the first arm 14 from its position in the waiting stage to a lower position for brewing, where the container 16 is immersed in the water, the microprocessor simultaneously initiates brewing time count-down, in this case four minutes, the motor is activated for forward and reverse rotation causing the first arm 14 to raise and lower the container 16 in the water for achieving efficient agitation of the coffee grains and water. The button 19 is still illuminated.

Figure 6 illustrates the stage at the end of brewing and the associated operations: The motor is activated to raise the first arm 14 and thus the container 16 to its position in the waiting stage of Figure 4, the microprocessor sets a criterion holding temperature, e.g. 80°C, the button 19 is extinguished and the button 20 (WARM) is illuminated.

Figure 7 illustrates the final serving stage and the associated

operations: When the coffee beverage is to be served, the ON/OFF button 19 is depressed and its lamp illuminates, the container 16 and heating means 18 are lifted up by the motor and button 19 is extinguished, coffee is served and the jug replaced on the stand. If there is coffee left which shall remain in the jug the WARM button 20 is depressed and illuminates, the motor moves the second arm 13 with the heating means 18 to the lower position and the first arm 14 to the intermediate dosing/waiting position. Button 20 is illuminated.

When all the coffee beverage is consumed and/or the apparatus is not being used either the WARM button 20 is depressed and illuminates or the ON/OFF button is depressed.

According to a modified embodiment of the invention, the motor may be adapted such that when the apparatus is in the waiting stage of Figure 4, i.e. the heating phase, it moves the arm 13 with the heating means 18 up and down to stir the water with small movements, thus inhibiting the occurrence of water layers at different temperatures.

For the brewing stage of Figure 5, and in accordance with a further embodiment of the invention, the motor may be disposed such as to move both arms 14, 13, and thus both container 16 and heating means 18 synchronously up and down with small movements in the liquid for ensuring that both water and coffee grains are put in motion.

An advantage with the inventive apparatus is that temperature holding is regulated and controlled with the aid of the tempera¬ ture sensor 50. The holding temperature is thus independent of the volume of liquid and the amount of coffee beverage in the jug. Known coffee percolators have a constant power feed in the temperature holding state. Consequently, if the liquid volume in the jug is small, the liquid will be kept at a temperature that is higher than that at which a large liquid volume in the jug will be kept. The holding temperature thus varies within wide

limits in the known coffee percolators, whereas it is constant in accordance with the invention.

Yet another advantage with the inventive apparatus is that keeping the beverage hot does not entail any risk of boiling dry. The temperature sensor, which is situated close to the heating means, monitors the temperature continuously. The program means is guided by the actual temperature detected by the sensor, and when the predetermined temperatures have been reached, power supply to the heating means is interrupted periodically or completely.

As will be apparent from Figures 8 - 10, the arms 13, 14 are pivotably mounted on a common, horizontal shaft 33. Figure 8 illustrates the position where water can be filled. The pin 26 has then lifted up both arms 13 and 14.

Figure 9 show the state, e.g. for the stage of Figure 4, where the water is being heated by the heating means 18 and the container 16 is filled with coffee grains. The toothed segment 24 has here been turned anticlockwise with the aid of the motor such that the second arm 13 has reached its lower position. In this position the disc 25 activates an unillustrated microswitch causing the motor to stop and a voltage to be supplied to the heating means 18.

Figure 10 shows the state obtained at the stage of Figure 5. The water has now reached the predetermined temperature 94°C, the temperature having been continuously monitored by the sensor during heating. When the actual temperature coincides with the programmed criterion value the motor is started and its pinion 23 turns the segment 24 anticlockwise to the position in Figure 10. During this movement the first arm 14 with the container and lid is moved to the lower brewing position, so that the coffee grains come into contact with the water. To ensure that the water passes through the grains and that all the water is at the criterion temperature, the arm 14 is raised and lowered to a

limited extent by the electronics causing the motor alternatingly to drive forwards and in reverse. After four minutes the motor lifts the first arm 14 with the container 16 to the intermediate position (the dosing/waiting position). The temperature mean value is simultaneously lowered to the holding value, e.g. 80°C.

The invention can be modified and varied in many different ways within the scope of the accompanying claims. For example, the electronic unit has been described as being programmed with a given thermal value and a time value. These two values are normally not adjustable extraneously, but if desired, knobs can be provided on the unit to facilitate individual setting of desired brewing temperature and time. Similarly, the drive of the illustrated cam system, which is common to both arms, can be replaced by a journaled disc 34 provided with the previously mentioned pins 26, 27. This disc is caused to rotate with the aid of a spiral bimetal spring 35 (Figure 11), one end of which is fixed to the stand, and the other to the disc at a distance from its centre.

Figure 12 illustrates an alternative embodiment, where the bimetal springs 36 and 37 act directly on the respective arm 13 and 14.

Figure 13 illustrates an alternative embodiment of the container 16. The arm 14 is here replaced by an arm 38 mounted in the same way as arm 14 and provided with the same cam surfaces 30, 31. At its free end the arm 38 is provided with a bucket or receptacle 42. The coffee grains are dosed into a filter bag 43, which is then closed, placed in the receptacle and kept in position by a spring loaded arm 39 mounted on a shaft 40 in the arm 38.

The arm 39 is formed such as to provide a nipping grip 41. This embodiment also permits the use of ready-made tea or coffee bags.

It will be understood that in the embodiments illustrated in

Figures 11 and 12, the bimetal springs 35 - 37 are supplied with electric power under control from the electronic unit such that the arms 13, 14 are caused to assume the positions illustrated in figures 1 - 7.