Method for Producing Coffee and Coffee Machine for Carrying Out the Method

The present invention concerns a coffee machine for producing liquid coffee from coffee powder.

Coffee machines are known in a number of different embodiments. Some of these are automatic machines operating with two pistons moving synchronously. In these cases, the quantity of coffee powder though predetermined is not scalded in a loose state with hot water; the result being that the relatively roughly ground coffee powder fails to properly swell-up, causing the aroma to suffer thereby. Therefore, a larger quantity of coffee powder is needed for obtaining and aromatically stronger coffee.

The invention has as its object the scalding of finely pulverized, loose coffee powder by means of working pistons moving independently of each other in a scalding chamber for thus obtaining aromatically strong coffee from a relatively small quantity of coffee powder. According to the invention, this object is achieved by using a coffee machine having the claimed features. In addition, separately actuated working pistons meter the quantity of coffee powder and thus predetermine the aromatic strength of the coffee produced.

The attached drawings show an exemplary embodiment of the coffee machine as described below in the description of the best mode embodiment. In particular,

FIG. 1 shows a lateral view of the coffee machine,

FIG. 2 shows a vertical sectional view,

FIG. 3 shows a sectional view taken along line III--III of FIG. 2,

FIG. 4 shows a vertical sectional view of the upper working piston on taken along line IV--IV of FIG. 5, turned by 180.degree.,

FIG. 5 shows a top view of the upper working piston of FIG. 4,

FIG. 6 shows a vertical sectional view of the lower working piston taken along line VI--VI of FIG. 7,

FIG. 7 shows a top view of the lower working piston of FIG. 6.

Two spaced horizontal carrier plates 1, 2 and two vertical rods 3 constitute the machine frame. The carrier plates 1, 2 are fixedly positioned in relation to the vertical rods by means of bolts 4 engaging grooves provided on the rods 3. A cylinder 5 open both at its upper and its lower end is fixedly mounted within the carrier plate 1. Two pistons, an upper piston 6 and a lower piston 7, are arranged to penetrate the cylinder 5. FIGS. 1 and 2 of the drawing show the upper piston 6 spaced vertically above the cylinder 5. The lower piston 7, on the other hand, partially engages the cylinder 5, being thus in a state of working readiness. When lowered, the piston 6 assumes the position indicated in FIG. 2 by dotted lines and closes the cylinder 5 at the upper end thereof. The space between the pistons 6 and 7 and the inside wall of the cylinder 5 defines a scalding chamber 8 destined to receive the coffee powder from which coffee is intended to be extracted. The outer dimensions of the pistons 6 and 7 are fitted to the inner diameters of the cylinder 5 and the scalding chamber 8. A traverse 10 is fixedly mounted by means of screws 9 to the upper ends of the vertical rods 3. An entrainer 12 provided with ball bearings 11 and displaceable in the vertical direction is positioned on the vertical rods 3. A guide rod 13 fixedly mounted on the entrainer 12 by means of screws 14 is arranged to pass through the carrier plate 1 and to partially engage the carrier plate 2. The guide rod 13 is surrounded by an entrainer bushing 15, which carries a pivot member 16 above the carrier plate 1. Upon rotation of the entrainer bushing 15 the pivot member 16 is taken along and is brought in position above the cylinder 5 or outside of the same. The pivot member 16 is provided with a conical bore 17 downwardly decreasing in diameter, its smallest diameter being equal to the diameter of the scalding chamber 8 within the cylinder 5. A water supply conduit 18, communicating with the passage 19 and opening into the lower side of the piston 6 as shown in FIG. 4, is connected to the piston 6. Lateral distributing channels 20 leading to the lower side of the upper piston 6 depart from the passage 19. The lower piston 7 has a shaft portion 7' provided with a central passage 21 arranged to communicate with a coffee drain conduit 22. The conduits 18 and 22 are both suitably flexible and consist of plastic or metal.

Mounted on a push rod 7" fixedly connected to the piston 7 is a piston disc 23 arranged within a pressure chamber 24 within the carrier plate 2. An oil channel 25 originates in the closure plate 26 and opens into the pressure chamber 24. A further oil channel 25' originates in the closure plate 27 and leads into the pressure chamber 24 from above. The oil channels 25, 25' are arranged to communicate by way of conduits with an oil pressure generator of known type and not separately shown in the drawing. The guide rod 13 penetrates below into a pressure chamber 28 arranged within the carrier plate 2. The guide rod 13 is provided with a piston disc 29 which reciprocates within the pressure chamber 28 and has the function of vertically displacing the entrainer 12 with the piston 6. The reference numeral 30 refers to an oil channel originating in the closure plate 26' and leading to the pressure chamber 28. An oil channel 32 leads form the closure plate 33 to a pressure source not separately shown. The piston 7 is also provided with distributor channels 20' leading from its upper side to the central passage 21. Mounted above the upper carrier plate 1 on the bearing 34' is a toothed gear 34 engaged by a toothed rack 35 displaceable transversely to the guide rod 13. The toothed rack 35 is displaceable within certain limits in both directions by means of conventional, oil-pressure controlled and piston-operated actuating elements not separately shown in the drawing. In the course of such displacement, the pivot member 16, which enables coffee powder to be fed into the cylinder 5 and later the coffee powder pushed out by the piston to be carried away, is taken along. The pivot member 16 may be set in position below the coffee powder feeder 36, as indicated in FIG. 1 with dashed lines, for filling the bore 17 with coffee powder, or else over the cylinder 5, as shown in FIG. 2.

The pistons 6, 7 and the rack 35 for positioning the pivot member 16 are hydraulically actuated in independent manner.

The coffee machine with its components for carrying out various motions and functions is controlled by electronic devices of known types.

Coffee is made by introducing loose coffee powder into the scalding chamber 8 between the two separately controlled pistons 6 and 7. Subsequent to introducing the loose coffee powder into the scalding chamber, the latter is closed by lowering upper piston 6 and hot water is supplied through the upper piston 6. The coffee powder is then allowed to swell-up so as to obtain strong aromatic coffee from a relatively small quantity of coffee powder. Compression is then applied to the swollen coffee powder by sliding lower piston 7 into the scalding chamber 8. The coffee so formed is drained off through the central passage 21 in this lower piston. Finally, the upper piston 6 is removed from the scalding chamber and the compressed coffee powder is pushed out of the upper end of cylinder 5 by sliding the lower piston 7 further into the scalding chamber. After the compressed coffee powder has been pushed out of cylinder 5 by lower piston 7, it is carried away by displacement of pivot member 16.