Extractiondevice of coffee for a coffee machine

The invention relates to an extraction device for the generation of Coffee for a coffee machine according to the preamble of the following Claim 1.

An extraction device is disclosed in EP-B-0299399. it includes one along in cooperation with a drive apparatus a longitudinal guide between predetermined positions back and forth adjustable Brewing cylinder for receiving coffee powder and two for Brewing cylinder coaxial, relatively adjustable piston. The coffee powder is filled through a side feed opening of the brewing cylinder, wherein a front side open end of the brewing cylinder by a the two pistons, the substantially fixed first piston closed, is maintained. When adjusting the brewing cylinder in one Direction via the first piston, the first piston bounded together frontally with the second, co-moving with the brewing cylinder piston a brewing chamber and ensures compacting the filled coffee powder. In this position by a piston brühendes water pumped into the brewing chamber and through the compacted coffee powder and then the produced coffee by the other piston to an outlet the coffee transported. During the subsequent adjustment of the brewing cylinder in the other direction the spent coffee powder by the second piston from the now shared by the first piston Brewing cylinder end expelled.

In another genus moderate apparatus according to the document US Patent No. 5,275,089 are also two to brewing cylinder adjustable piston and a filling opening for filling the coffee powder PROVIDED Block provided. On the inside of this cylindrical block is a Sleeve and a piston arranged longitudinally movable. In the filling position is this block at the other sleeve part with the other piston the end face of, while in the eject position, they are separated from each other. In the brewing position of the piston located at the attachment comes to be within the cylinder part. Due to the necessity of this Sleeve in the block and its displacement as well as of the associated in their Piston is a complicated structure of this extraction device given.

The present invention is based on the object, the proven itself Extracting apparatus of the type mentioned to be further improve and make more space-saving.

According to the invention this object is achieved by an extraction device solved with the features of claim 1.

Further preferred embodiments of the inventive extraction device form the subject of the dependent claims.

With the inventive division into the brewing cylinder and into a Accessory, one of which the actual, enclosing of the brewing chamber and adjustable by the drive device Brühzylinderteil forms and the additional part on the closable by the first piston arranged end of the brewing cylinder and the filling opening is provided for filling the coffee powder, the two cylinder parts when adjusting the Brühzylinderteils in one direction front side pressed together zusammenverstellt and when adjusting the Brühzylinderteils be separated from each other in the other direction, can so that an axial gap is formed through which the spent may fall out coffee powder, the length of the brewing cylinder and also necessary to expel the spent coffee powder Hub of the second piston can be shortened, thereby the total length of the Extraction device is reduced.

In addition, the ejection process is shortened, and not least the Material for the truncated parts saved. In addition, the fill opening having, uninvolved in the actual brewing process accessory of a cheaper material such as plastic and in a simpler Procedures are made as the existing stainless steel Brewing cylinder, are made in the now no lateral filling opening have to be.

The invention will be described with reference to the drawing. It show:<dl tsize="6" compact="compact"><dt>Fig. 1</dt><dd>an embodiment of an inventive extraction device for a coffee machine in a perspective view;</dd><dt>FIG. 2</dt><dd>a section along line II - II in Fig. 3;</dd><dt>Fig. 3</dt><dd>in longitudinal section the extraction apparatus of FIG. 1 in a Starting position;</dd><dt>Fig. 4</dt><dd>in longitudinal section the extraction apparatus of FIG. 1 in a brewing position;</dd><dt>Fig. 5</dt><dd>in longitudinal section the extraction apparatus of FIG. 1 in a Knockout position</dd><dt>Fig. 6</dt><dd>another embodiment of an inventive extraction device in a perspective view, and</dd><dt>Fig. 7</dt><dd>a view of the embodiment of Fig. 6, in which the associated holder is omitted.</dd></dl>

In Figures 1 to 5 is an extraction apparatus 1 for producing coffee shown, which finds use in an automatic coffee machine. It has a brewing cylinder 2 with a cylindrical portion 20 and an axially with this joinable cylindrical attachment 22 on how is discussed in detail below. One of these parts, the tubular Brühzylinderteil 20 is attached to a carriage 3 and is with this in cooperation with a driving device 4 in its axial direction moved between predetermined positions back and forth and thereby guided on two guide rods 5. 6 The guide rods 5, 6 are with their ends secured in a respective holder 7. 8

The driving device 4 comprises a force acting on the carriage 3 Drive spindle 9 which is rotatably supported in the two holders 7, 8, and via a belt drive 11 with a driving motor 10, preferably a DC motor (direct current motor) is in drive connection. The Axis of the drive spindle 9 lies in a longitudinal center plane of the extraction device 1 which extends between the two guide rods 5, 6th

In the position of the carriage 3 shown in Fig. 3 is located on a front side open end 21 of the fixed to the carriage 3 connected Brühzylinderteils 20 of the attachment 22 to which a lateral filling opening 24 provided for filling coffee into the brewing cylinder cavity is. The additional part 22 is connected to a guide member 23 and with this on the guide bars 5, 6 and loose using the drive spindle 9 guided (but is not supported by the drive spindle 9 driven). On the guide member 23 act in two guide rods 5, 6 Integrated springs 25, 26 (see. FIG. 2) that the guide member 23 at each one to the respective guide rod 5, 6 radially and with this example screw stop 27, press 28, and the together axially in this position, the additional member 22 and the cylindrical portion 20th

The adjustable in its axial direction brewing cylinder 2 are two relatively , Assigned to each adjustable piston 31 32 coaxially. The first, in substantially fixed piston 31 is in two parts. While a piston member is fixedly secured in the holder 33 7, the other piston part 34 this one slightly axially movable and resiliently supported at this. Between the two piston parts 33, 34 a pressure spring 35 arranged. The two piston parts 33, 34 are carried at its periphery a ring-shaped, provided with a U-shaped cross section seal 37 interconnected, with their ends around at both piston parts 33, 34 is fixed. The compression spring 35 strives to provide the two piston parts 33, apart compress 34 while the seal 37 oblong to stretch. During the pressing of the movable piston member 34 to the stationary Piston portion 33, against the force of the compression spring 35, the seal pressed radially outward 37 and thus in their sealing function position brought. The first piston 31 closes this the end face open end of the brewing cylinder. 2

The second piston 32 is guided in Brühzylinderteil 20th At the Scope of this piston 32 is an annular seal 38 available. The second piston 32 extends with its piston rod 40 from the Brühzylinderteil 20 by a frontal brewing cylinder end portion 39 therethrough. The Piston rod 40 is having at its end with a circumferential groove 42 a Head 41 is preferably provided in plastic with which it in a the holder 8 attached bracket 43 is latched. The bracket 43 has with the circumferential groove 42 cooperating rod-shaped spring elements 44, which extend substantially tangentially to the circumferential groove 42, and are forced apart during locking. Of course would also be a different locking device imaginable. In the shown in Fig. 3 Position is the second piston 32 at the end part 39 and the piston rod 40 is locked in the holder 43rd

In the starting position the extraction device 1 shown in Fig. 3 , the ground coffee through the side, with a coffee grinder associated filling opening 24 is filled into the brewing cylinder 2 will. With advantage can in addition part 22 two opposing and provided each with a mill corresponding lateral filling openings 24 be.

After a defined portion of coffee powder in the two by the Piston 31, 32, the brewing cylinder 2 and the additional part 22 limited chamber has been introduced, is now the carriage 3 with the Brühzylinderteil 20 by means of the driving device 4 in the direction of arrow A of FIG. 3 set in motion, whereby the fitting of the cylinder part 20 accessory 22 moved along with the guide member 23 and thereby from the in Guide rods 5, 6 integrated springs 25, 26 to the Brühzylinderteil 20 remains pressed. The cylinder part 20 and the attachment 22 are on the first piston 31 (while compressing his two Piston parts 34, 33) in a pushed 4 the position shown in Fig.. From moving in the direction of arrow A brewing cylinder 2 but also the second piston 32 under disengagement of the head 41 from the holder 43 taken and up to a certain distance from the fixed first piston 31 moves toward. Thereby, the chamber with the Coffee powder decreases to a predetermined degree and the coffee powder compressed or compacted.

In this in Fig. 4 shown brewing position, the actual brewing process be carried out by by a piston (example through channels 32 'of the second piston 32) brühendes water or Steam into the sealed by seals 37, 38 and cavity through pumped the ground coffee and the coffee produced by the other Flask (for example, through channels 31 'of the first piston 31) to a transported from the drawing, not visible outlet of the coffee machine becomes.

After completion of the brewing process by means of the drive device 4, the carriage 3 with the Brühzylinderteil 20 in the other direction, set (arrow B of FIG. 4) in motion. The one with the guide member 23 connected additional part 22 is initially at the Brühzylinderteil 20 pressed and is under the action of the spring 25, 26 is moved back with this, until the guide member 23 to the to the guide rods 5, 6 associated stops 26, 27 comes to rest. Now the left standing, provided with the filling opening 24 (or the filling openings 24) Additional part 22 of which continue to the slide 3 in the direction of arrow B moving Brühzylinderteil 20 isolated and characterized an axial gap formed between these two parts. By Brühzylinderteil 20 is adjusted in the direction of the arrow B and the second piston 32 until the head 41 snaps back into the holder 43rd But since the Brühzylinderteil 20 moved with the slide 3 in the direction of arrow B to the holder 8 toward is, to an end face 46 of the brewing cylinder end part 39 on a mating surface 47 of the locked in the bracket 43 head 41 to rest comes (see. FIG. 5), is a relative movement between the second Piston 32 and the Brühzylinderteil 20 instead, and the used coffee dose or the coffee grounds are by the second piston 32 from the Brühzylinderteil 20 ejected in the axial gap between the parts 20, 22 and falls into an underlying collection container (in the drawing not shown).

With the inventive division of the brewing cylinder 2 in the Start a longitudinal guide (guide rods 5, 6) guided cylindrical part 20 and in the additional part 22, one of which is the actual, the brewing chamber enclosing and adjustable by the drive device 4 Brühzylinderteil 20 forms and the additional part 22 with the fill opening 24 to Filling the coffee powder is provided, wherein it when adjusting the Brühzylinderteils 20 pressed against each other frontally in one direction A zusammenverstellt and when adjusting the Brühzylinderteils 20 in the other direction B can be separated from each other so that a Axial gap arises ejected through which the spent coffee powder may be, the length of the brewing cylinder 2 as well as the necessary to expel the spent coffee powder stroke of the second piston 32 can be shortened, thereby the total length of the Extraction device 1 is reduced.

In addition, the ejection process is shortened, and not least the Material for the truncated parts saved. In addition, the fill opening 24 having, uninvolved in the actual brewing process accessory 22 of a cheaper material such as plastic and in a simpler Procedures are made as the existing stainless steel Brühzylinderteil, made in the now no lateral filling opening must become.

Of course, would also be other embodiments of the invention Extractor conceivable. This could, for example a alternative drive device as shown in the drawing application find.

The use of a DC motor in the manner of a stepper motor allows a highly accurate and repeatable position adjustment with consistent Pressure, constant coffee grounds Portion, the Outcast must be, etc.

According to FIG. 6 and FIG. 7, in place for the introduction of the coffee powder the means for pressing said frontal cylinder part 20 with the addition part 22 by at least one spring 25, 26 even just a be provided on the additional part concerns the cylinder part.

The same design as those parts of the extraction device according to FIG. 1 to FIG. 5 are given the same reference numerals and subsequently no longer be explained in detail.

The cylindrical attachment 22 is on when filling coffee powder one side with the brewing cylinder 2 in stop, as shown in FIG. 3 is illustrated, opposite it surrounds the piston 31, so that a chamber is formed. Then, the not shown in detail by a Mill ground coffee through the fill opening 24 in the attachment 22 are brought into this chamber formed.

Subsequently, analog, as shown in Fig. 3 can also be seen, the cylinder part 20 and with it the piston 32 further against the fixed Piston 31 is pushed towards, until the cylinder part 20 this piston encloses 31st At the same time, the additional member 22 is moved in the same direction, until it comes to lie on the rear side of the piston. In this Position is pressed the coffee powder into a cake and then the hot water for the production of coffee is pressed by the piston.

After completion of the brewing process is initially the cylinder part 20 from Piston 31 is retracted. After a certain distance is also Piston 32 and by the assignment of parallel to the guide rods 5, 6 arranged sliding rods 27 ', 28' and corresponding stops also the additional part 22 to the loading position, ie to the front Piston 31 (see Fig. 5), pulled. Once the cylinder part 20, the End position reached in the bracket 8, the coffee cake is the piston 32 is ejected.

This is a simple solution in terms of the adjustment of the attachment 22 was obtained without operational disadvantages would arise.