Abstract:
A mechanically and hydrodynamically operated brewing unit ( 1 ) for automatic beverage vending machines includes a rotatable base ( 3 ) provided with a compartment ( 15 ) that acts as a brewing chamber, means to let water under pressure into said compartment, means to connect said compartment with the point at which the brewed beverage is dispensed, and a brewing head ( 4 ). This brewing head is comprised of a hollow containment structure ( 279 ), a first hollow piston ( 28 ) that is housed in said containment structure movably relative thereto, a second piston ( 29 ) that is accommodated in said first piston movably relative thereto, and elastic means ( 30 ) contrasting the movement of said second piston. The brewing unit is characterized in that said first piston and said second piston are operated by the direct action of a fluid under pressure.

Description:
FIELD OF THE INVENTION 
     The present invention refers to a mechanically and hydrodynamically operated brewing unit for automatic beverage vending machines, which is adapted to prepare the beverages to be dispensed starting from so-called capsules, preferably hermetically sealed ones, containing the raw material to be brewed. 
     BACKGROUND OF THE INVENTION 
     In the course of the last few years, there has been a growing use, in automatic vending machines for preparing and dispensing beverages, of so-called capsules, in particular such capsules of a hermetically sealed type, which contain a raw material ready for brewing. These sealed capsules are constituted by semi-rigid envelopes provided with a collet, which create a physical barrier separating their contents from the surrounding ambient. In beverage vending machines, capsules of this kind are certainly by far preferably over both the traditional pre-filled filters, i.e. filters that are filled in advance with the raw material for brewing, and those capsules that are constituted by a semi-rigid envelope comprising a pair of surfaces acting as filtering elements, i.e. elements that enable the brew to pass therethrough, while retaining the raw material within the same capsule. The main advantage deriving from the afore-mentioned hermetically sealed capsules lies in the fact that the raw material contained in these capsules is effectively and reliably preserved from any contact with the outside ambient, thereby ensuring a maximum extent of hygiene, as well as an optimum preservation of the flavor, fragrance and the other properties of the content thereof over prolonged periods of time. This is basically why this kind of packaging is highly preferable, especially in those vending machines, which prepare and dispense beverages of an aromatic kind, such as for instance coffee, tisanes or other kinds of hot infusions. 
     Largely known in the art is the fact that the use of sealed capsules in automatic vending machines requires these machines to be provided with brewing units that comprise devices adapted to accommodate and hold the capsules themselves, as well as devices adapted to ensure the water-tightness of the brewing chamber and devices adapted to pierce the capsule in order to enable water to come into contact with the raw material contained therein. When a brewing unit of the just described kind is in operation, some of the members constituting the same unit are set in motion, so as to displace relative to each other, by means of appropriate mechanical devices that are usually operated by an electric motor. The fact that such brewing units are operated solely by mechanical members and devices is disadvantageous in that the operating accuracy of such mechanical members, and as a result the proper production of the beverage, are strongly dependent on the manufacturing and assembly tolerances of the various mechanical parts involved, as well as the increasing wear-down state of the materials which said mechanical parts are made of. To particularly suffer from this drawback is chiefly the mating accuracy of those elements constituting the brewing unit, which are temporarily associated with each other in order to tightly seal the brewing chamber during the beverage preparation process. It can be readily appreciated that, if such a mating accuracy is not perfect, or becomes imperfect after a certain number of working cycles of the brewing unit, there will occur leakage problems involving both liquid and raw material, which eventually affect the quality of the beverage being produced. Another device that is particularly affected by this drawback is one that causes the capsule to be pierced. In prior-art brewing units, the piercing operation is performed with the aid of means that press the capsule against a device comprising one or more projections that are so shaped as to be able to pierce the material which the capsule is made of. Even in this case, it can be readily appreciated that if the pressing action intervening between the capsule and the piercing device cannot be brought about to full intensity, i.e. loses some of its force due to the inaccuracy of the mechanical devices moving or actuating the various parts forming the brewing unit, the resulting beverage will not be produced correctly. 
     Known from the disclosure in U.S. Pat. No. 6,431,055 is a brewing unit for the preparation of espresso coffee, the component parts of which are actuated by the action of pressurized water from the machine pump without any further electric or pneumatic control being used. The brewing unit described in this patent publication is designed to work with the use of loose coffee powder or filter bags that are pre-filled with raw material, of the type of those provided in the form of a capsule constituted by a semi-rigid envelope with a base and a bottom acting as a filter. Further to the already mentioned poor preservation of the raw material contained in capsules provided with filtering surfaces, the brewing unit described in U.S. Pat. No. 6,431,055 can by no means operate by using the more advantageous capsules of the hermetically sealed type, since no device or member adapted to enable the capsules to be dully pierced is provided therein. 
     SUMMARY OF THE INVENTION 
     It therefore is the object of the present invention to provide a mechanically and hydrodynamically operated brewing unit for beverage vending machines, which is capable of carrying out the preparation of beverages with the aid of capsules, preferably hermetically sealed ones, containing the raw material to be brewed, while doing away with the drawbacks and disadvantages of prior-art brewing units of this kind. 
     Within this general object, it is a purpose of the present invention to provide a brewing unit, which is capable of operating effectively, although not limitatively, with capsules of the hermetically sealed type. 
     Another purpose of the present invention is to provide a brewing unit, the operation of which is fully independent of manufacturing and assembly tolerances of the various mechanical component parts, as well as of the progressing wear and tear of the materials which said component parts are made of, the brewing unit itself being so sized and designed as to be extremely compact and capable of being accommodated in a beverage vending machine of the usual kind. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       According to the present invention, these aims are reached in a capsule feeding apparatus for beverage vending machines incorporating the characteristics as described in a first aspect of the present invention. Features and advantages of the present invention will anyway be more readily understood from the description that is given below by way of non-limiting example with reference to the accompanying drawings, in which: 
         FIG. 1  is a cross-sectional view of the brewing unit in a phase of the operation thereof; 
         FIG. 2  is a cross-sectional view of the brewing unit shown in  FIG. 1 , but in a second operating phase thereof; 
         FIG. 3  is a cross-sectional view of the brewing unit shown in  FIG. 1 , but in a third operating phase thereof; 
         FIG. 4  is a cross-sectional view of the brewing unit shown in  FIG. 1 , but in a fourth operating phase thereof; and 
         FIG. 5  is a cross-sectional view of the brewing unit shown in  FIG. 1 , but in a fifth operating phase thereof. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates a brewing unit  1  for automatic beverage vending machines, which is constituted by a box-like containment body  2  acting as an outer casing for the entire brewing unit  1 , a base  3  and a brewing head  4 . Within the box-like containment body  2 , in addition to the base  3  and the brewing head  4 , there are also housed the mechanical members that form a kinematic chain adapted to operate both the base  3  and the brewing head  4 . In particular, these mechanical operating members include a crank  5 , to which there is rotatably connected the first end portion of a connecting rod  6 , the second end portion of the connecting rod  6  being connected to the brewing unit  4 . Firmly joined to the crank  5  there is a cam  7 , which interacts with the lower contour  8  of an ejection lever  9  provided with an upper contour  10  that controls the ejection of the capsule  11  from the base  3 . In the crank  5  there are provided two recesses  12  adapted to be engaged by a detent lever  13  that is rotatably connected to the box-like containment body  2  and prevents the crank  5  from rotating in either one of the two possible directions of rotation during the beverage preparation phases. A movement of this detent lever  13  is opposed by a first spring  14 , through which said detent lever  13  is connected further to the box-like containment body  2 . 
     The base  3  of the brewing unit  1  is constituted by a hollow body that defines a compartment  15  accommodating the capsule  11 , this compartment being open on top and comprising a bottom wall  16 . The compartment  15  is adapted to act as the brewing chamber for the preparation of the beverage. Said bottom wall  16  is provided with a plurality of projections  17  that are so shaped as to be able to pierce the material forming the capsule  11 . Each one of said projections  17  comprises an opening enabling the beverage to flow out towards means  18  connecting the brewing chamber to the beverage dispensing point. The bottom wall  16  is made in such a manner as to be capable of serving as a filter during the outflow of the beverage from the brewing chamber. 
     Within the hollow body of said base  3 , and along the longitudinal axis thereof, there is slidably mounted a bar  19  that causes the capsule to be ejected from the compartment  15  in which it is accommodated. This bar  19  comprises a first end portion  20  in contact with the upper contour  10  of the ejection lever  9 , and a second end portion  21  that faces into the compartment  15  at the bottom wall  16  thereof. The movement of this bar  19  is opposed by a second spring  26  connected to the base  3 . 
     The base  3  is rotatably mounted onto the box-like containment body  2  and comprises a pin  22  engaging a first guiding profile  23  that is firmly joined to the connecting rod  6  and suitable sized and shaped so as to coordinate the movement of the base  3  with the movement of the brewing head  4  and, in particular, to bring about a rotation of the base  3  when the connecting rod  6  and, as a result, also the brewing head  4  are displaced due to the movement of the crank  5 . The base  3  is capable of moving between a first position, in which the capsule  11  is loaded into the receiving compartment  15 , and a second position, in which the beverage is brewed. Said first position is such that the compartment  15  is moved to a position in which it is facing the outlet aperture of a feeding conveyor  24  designed to dispense the capsule being stored in a proper reservoir (not shown). Said second position, on the other hand, is such that the receiving compartment  15  is moved into a position in which it is facing the brewing head  4 . In order to ensure that the base  3  will correctly and accurately stop at the above-described end positions thereof, the pin  22  is designed to further engage a second curvilinear guiding profile  25 . 
     The brewing head  4 , which forms a hydrodynamic actuation unit, comprises a hollow containment structure  27 , in which there is mounted in a tightly sealed manner a first hollow piston  28  that is movable relative to the same structure  27 . Within this first piston  28  there is mounted, again in a tightly sealed manner, a second piston  29  that is movable relative to said first piston  28 , the movement of this second piston being opposed by elastic means  30  connected to the hollow containment structure  27 . The second piston  29  extends along the longitudinal axis thereof so as to form a hollow interspace  33 , which is associated to means  32  for letting pressurized water into the compartment  15  acting as a brewing chamber. The second piston  29  is provided with a circumferential edge that is so shaped and made as to be able to pierce the material forming the capsule  11  when an appropriate pressure is exerted on the capsule  11  by the same piston  29 . The bottom surface  31  of the second piston  29  comprises a plurality of apertures (not shown in GIG.  1 ) that are provided in order to enable the water to enter the compartment  15 . 
     To the containment structure  27  there is connected a conduit  34  within which there moves a fluid under pressure, which in this way directly controls the movement of the first and the second piston  28  and  29 . This movement of said pistons is practically imparted by said fluid under pressure being injected into or extracted from the interstices comprised between the containment structure  27  and the first piston  28 , as well as the interstices comprised between the first piston  28  and the second piston  29 . The above-mentioned fluid may be in its liquid state or in its gaseous state, but is preferably constituted by the water flowing in from the same source used to produce the beverage. The fluid itself is put under pressure by an appropriate apparatus, such as for instance a pump or a compressor. 
     The direction of the relative displacement of the second piston  29  with respect to the first piston  28  is determined by the direction of the force resulting between the action of said elastic means  30  and said direct action of the fluid under pressure; in particular, the movement of the second piston  29  starts when the pushing force exerted thereunto by the fluid under pressure exceeds the biasing force of the elastic means  30 . Should for any reason whatsoever an overpressure condition occur within the above-mentioned interstices, the pressurized fluid is allowed to flow out through a safety bleeder  35  so as to collect into a reservoir (not shown). 
     Accordingly, the way in which the unit according to the present invention operates is as follows. 
     With reference to  FIGS. 1 and 2 , after the capsule  11  coming from the feeding conveyor  25  has occupied the receiving compartment  15 , the rotation of the crank  5  and the associated cam  7  in the direction indicated by the arrow F causes the base  3  to rotate and the brewing head  4  to descend along the first guiding profile  23 . The travelling length of the brewing head  4  is so sized and designed as to ensure that the brewing head itself is able to move all along until it comes quite close to the base  3 , however without coming into contact therewith ( FIG. 2 ). When the brewing head  4  has covered the entire allowable travelling length thereof, the detent lever  13  slides into and engages one of the recesses  12  so as to prevent the brewing head  4  from possibly moving away from the base  3  accidentally. At this point, as is best shown in  FIG. 3 , a fluid under pressure is injected through the conduit  34  into the interstices comprised between the containment structure  27  and the first piston  28 , thereby bring about a displacement of said structure  27  and said first piston  28  relative to each other, this relative movement continuing until said first piston  28  eventually comes into contact with the base  3  and the capsule  11 . The pushing action exerted by the fluid under pressure contributes to the compartment  15  being at this point closed and sealed hermetically, so that it can now act as the brewing chamber. As the fluid under pressure keeps being injected through the conduit  34  ( FIG. 4 ), the same fluid eventually fills up those interstices that are comprised between the first piston  28  and the second piston  29 , thereby overcoming the contrasting action exerted by the elastic means  30 . The second piston  29  slides relative to the first piston  28  and moves to occupy a portion of the compartment  15  with the bottom surface  31  thereof. In this way, the circumferential edge of the second piston  29 , as it is pressed against the capsule  11  by the action of the fluid under pressure, pieces the upper surface thereof, while the piston&#39;s bottom surface  31  urges the same capsule  11  towards the bottom wall  16  of the base  3 , thereby causing the capsule itself to be further pierced by the projections  17 . 
     Upon the capsule  11  having been so pierced, and as the fluid under pressure keeps being present in the conduit  34 , water under pressure is let into the compartment  15  via the means  32  connected to the hollow interspace  33 . This pressurized water comes into contact with the raw material contained in the capsule  11 , thereby forming a beverage that is capable of flowing out of the compartment  15  through the apertures provided in the projections  17 , and running towards the connecting means  18  to the dispensing point. 
     Then, when the desired amount of water under pressure has flown through the capsule  11  and left the compartment  15 , i.e. when the desired dose of beverage is reached, the process for ejecting the exhausted capsule  11  is started. In the position in which the base  3  and the brewing head  4  are lying at this point, i.e. the position in which the brewing head  4  is engaging the base  3 , as illustrated in  FIG. 4 , while the fluid in the conduit  34  continues being kept under pressure, the water still present within the capsule  11  is removed by sucking it up through the means  32 , thereby preventing the water and raw material mixture still remaining in the capsule  11  from being able to spill out from the capsule and soil the brewing unit  1 . Next, the fluid under pressure is extracted through the conduit  34  from the interstices between the first piston  28  and the second piston  29 , as well as those between the containment structure  27  and the first piston  28 , so that said pistons are able to slide backwards, thereby retracting into the containment structure  27  and making in this way the base  3  independent of the brewing head  4 . 
     Upon such retraction having been so completed, the crank  5  and the cam  7  firmly associated therewith are operated again the rotate in the direction indicated by the arrow F ( FIG. 5 ), thereby causing the base  3  to rotate accordingly and, at the same time, the brewing head  4  to move away from the base  3  along the first guiding profile  23 . During the rotation of the crank  5 , and prior to the base  3  completing its movement, the same  7  comes into contact with the lower contour  8  of the ejection lever  9 , which, via the upper contour  10  thereof, actuates the bar  19  so as to cause it to enter the compartment  15 , thereby causing the capsule  11  to be ejected from the base  3 . The action of this bar is most clearly illustrated in  FIG. 5 . Upon conclusion of the rotation of the crank  5 , the base  3  comes to lie in a position in which it faces the outlet aperture of the feeding conveyor  24 , whereas the brewing head  4  moves back into the resting position thereof, as illustrated in  FIG. 1 . At this point, the brewing unit  1  is ready to start a new cycle for producing another beverage. 
     Fully apparent from the above description is therefore the ability of the the present invention to effectively reach the afore cited aims and advantages by providing a brewing unit that is capable of operating effectively, although not limitatively, with capsules of the hermetically sealed type. Moreover, it is fully apparent that the operation of the brewing unit of the present invention, due to the use of a hydrodynamic actuating system, is fully independent of manufacturing and assembly tolerances of the various mechanical component parts, as well as of the progressing wear and tear of the materials which said component parts are made of, the brewing unit itself being so sized and designed as to be extremely compact and capable of being accommodated in a beverage vending machine of the usual kind. 
     It should be noticed that the materials used, as well as the shapes and the sizing of the individual items, may each time be selected so as to more appropriately meet the particular requirements or suit the particular application, without departing from the scope of the present invention. 
     The various component parts entering the construction of the brewing unit according to the present invention shall certainly not be provided solely in the afore illustrated embodiments, but may rather be used or implemented in a number of different embodiments, again without departing from the scope of the present invention.