Abstract:
The present disclosure includes an extraction assembly for use in an automatic espresso brewer. The extraction assembly includes components and methods for controllably extracting espresso beverage from a quantity of brewing substance. The components, assemblies, and methods facilitate improved control and operation of the extraction assembly and improve the reliability of the extraction assembly. The brewing substance is compacted between a pair of opposing pistons. Compacting force is monitored through at least one sensor carried on the extraction assembly to provide a signal to a controller. A predetermined compacting force may be programmed into the system for all brewing cycles or dependent upon the brewing substance used. The pair of pistons operates relative to a brew chamber for use in the espresso extraction process. The pistons provide compacting force and boundaries within the chamber and facilitate removal of a spent brewing substance puck at the end of the brewing cycle. Compacting force is monitored at the start of the brewing process and a predetermined force is required before the brewing process can be started. During the brewing process compacting force can be maintained and controllably adjusted. A variety of sensor methods and locations can be used to detect and monitoring compacting force.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application is a U.S. nationalization under 35 U.S.C. §371 of International Application No. PCT/US2012/027761, filed Mar. 5, 2012, which claims the benefit of priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/449,459, filed Mar. 4, 2011. The disclosures set forth in the referenced applications are incorporated herein by reference in their entireties′-entirety, including all information as originally submitted to the United States Patent and Trademark Office. 
    
    
     BACKGROUND 
     The disclosure relates to beverage brewing systems and in particular brewing systems which use a charge of brewing substance for use in pressurized brewing. Such pressurized brewing is often referred to as “espresso” brewing. Espresso brewing uses a relatively small charge of relatively finely ground coffee or other brewing substance for use in a confined brewing chamber. The brewing substance is compacted to a desired degree and then infused with pressurized water. Compaction of the brewing substance and infusion with the pressurized brewing water requires a sealed brewing chamber to facilitate proper brewing. 
     The beverage product produced in an espresso brewing process is referred to as “espresso.” Espresso tends to be a thicker beverage compared to drip, French press, cone, or other unpressurized brewing processes. Espresso tends to have a higher percentage of solubles and particulate matter and tends to be relatively viscous or “syrupy.” A variety of espresso brewing machines are available ranging from manual, semi-automatic, to fully automatic. In a manual process an operator grinds a quantity of coffee beans for use in the process. The ground coffee is loaded into a holder device often referred to as a “portafilter.” The portafilter is attached to a pressurized water dispensing head of the brewer. In this manner the ground coffee is contained in a closed, sealed space for brewing. The brewer is activated to controllably deliver pressurized brewing water to the coffee contained in the portafilter. The operator controls the machine for a selected period of time to produce a quantity of espresso beverage. 
     Fully automatic machines may include a control interface which allows a user to select a type of bean, quantity of espresso to be produced, and perhaps other characteristics. The fully automatic machine includes bean hoppers which may automatically deliver beans to a grinder and then dispense the ground coffee into a brewing chamber. Infusion with heated, pressurized water is automatically controlled by the machine after activation by the operator. At the conclusion of the brewing process a puck of spent, drained but moist, brewing substance is automatically removed from the brewing chamber and passed to a waste collection container for subsequent removal. 
     SUMMARY 
     The present disclosure includes an extraction assembly for use in an automatic espresso brewer. The extraction assembly includes components and methods for controllably extracting espresso beverage from a quantity of brewing substance. The components, assemblies, and methods facilitate improved control and operation of the extraction assembly and improve the reliability of the extraction assembly. The brewing substance is compacted between a pair of opposing pistons. Compacting force is monitored through at least one sensor carried on the extraction assembly to provide a signal to a controller. A predetermined compacting force may be programmed into the system for all brewing cycles or dependent upon the brewing substance used. The pair of pistons operates relative to a brew chamber for use in the espresso extraction process. The pistons provide compacting force and boundaries within the chamber and facilitate removal of a spent brewing substance puck at the end of the brewing cycle. Compacting force is monitored at the start of the brewing process and a predetermined force is required before the brewing process can be started. During the brewing process compacting force can be maintained and controllably adjusted. A variety of sensor methods and locations can be used to detect and monitoring compacting force. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The present disclosure will be described hereafter with reference to the attached drawings which are given as a non-limiting example only, in which: 
         FIG. 1  is general diagrammatic illustration of a extraction assembly of the present disclosure, the extraction assembly including connections to a water delivery system and a controller, the extraction assembly also including a frame on which a carriage is controllably driven by a drive mechanism being carried on the carriage relative to the frame, and a pair of pistons operative and retained relative to the fixed brew chamber for use in compacting brewing substance retained in a cavity of the brewing chamber, introducing water from the heated water system and dispensing an espresso beverage; 
         FIG. 2  is a diagrammatic illustration similar to that as shown in  FIG. 1  in which the extraction assembly is shown in a perspective view, illustrating and describing the structures and functions of the extraction assembly, the extraction assembly being positioned to receive a beverage brewing substance which has been dispensed into the cavity of the brew chamber for use in a brewing process; 
         FIG. 3  is the extraction assembly as shown in  FIG. 2  in which a first piston has been engaged by movement of the pistons resulting in retaining and compacting brewing substance between the first piston and a second piston, a first and second spring associated with the first piston providing relative spring force to facilitate compaction of brewing substance and at least one sensor carried on the extraction assembly providing compaction information to the controller; 
         FIG. 4  is an enlarged partial fragmentary view of a compressible gasket used in the extraction assembly and a corresponding filter and drain passage associated with the first piston; to prolong the life of the gasket seal, the compression for sealing occurs only when the compacting force is applied, the gasket seal otherwise rides freely on the inner surface of the brew chamber avoiding abrasion and friction; 
         FIG. 5  shows the extraction assembly after a brewing operation in which the first piston has been displaced upwardly causing a portion of the second piston carried in the brew chamber to be displaced upwardly after contacting a lower portion of the frame, the brew chamber being positioned stationary while the first piston continues to move relative to the second piston causing a puck of spent brewing substance to be positioned relative to the upper mouth of the brew chamber for removal therefrom; 
         FIG. 6  is an enlarged, partial fragmentary cross sectional view of a portion of a cam structure which is attached at upper and lower portions of the frame and is generally parallelly aligned with an adjustment screw of the assembly; 
         FIG. 7  is an enlarged, partial fragmentary view of a portion of the cam structure taken from  FIG. 5  showing a cam follower positioned in a cam slot for coordinating movement of the chute and wiper structure relative to the brew chamber, the chute facilitating dispensing of ground brewing substance into the cavity of the brew chamber at the start of the brewing process and the wiper facilitating removal of the puck from the chamber and second piston at the end of the brewing process by operation of the cam follower in the cam slot; 
         FIG. 8  is an extraction assembly as shown in the prior figures in which the cam follower acting along the cam slot operates to pivot a wiper relative to the brew chamber to displace a puck of brewing substance away from the chamber for disposal, the attached chute helps to transfer the used puck of brewing substance to the disposal bin; and 
         FIG. 9  is an enlarged partial fragmentary view of the limit detector detecting the limits of movement of the carriage relative to the brew chamber, which would limit the upward travel of the brew chamber to a position approximately as shown in  FIG. 2 , the compacting force sensor and the flow meter works in combination as a limit detector detecting the travel limit of movement of the carriage relative to the brew chamber to a position approximately as shown in  FIG. 3 . 
     
    
    
     The exemplification set out herein illustrates embodiments of the disclosure that is not to be construed as limiting the scope of the disclosure in any manner. Additional features of the present disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of illustrative embodiments exemplifying the best mode of carrying out the disclosure as presently perceived. 
     DETAILED DESCRIPTION 
     A general diagrammatic illustration of an extractor assembly  30  is shown in  FIG. 1 . The extractor  30  assembly is used to receive a quantity of brewing substance, contain the brewing substance during a brewing process to extract an espresso beverage, and then dispose of the spent brewing substance. The extractor assembly includes a frame  34  which is controllably movable relative to a generally fixed carriage  38  by drive mechanism  42 . A brew chamber  46  is attached to the carriage  38  and are fixed to the housing. The frame  34  by operation of the drive mechanism  42  moves relative to the fixed brew chamber assembly. A first piston  52  and a second piston  56  operate relative to the brew chamber for using during the brewing process. A chute and wiper structure  60  is pivotally attached to the frame so as to travel along with the brew chamber by operation of the drive mechanism  42  on the carriage  38 . A cam structure  62  is attached to the frame  34  at an upper beam  64  and a lower beam  66 . A cam follower  68  on the chute/wiper  60  is engaged with a cam slot  70  in the cam structure  62  (see  FIG. 2 ). 
     The frame  34  includes the upper and lower beams  64 ,  66  and a column  72 . A lead screw  74  of the drive mechanism  42  is attached to the upper and lower beams  64 ,  66 . While the lead screw  74  may be more appropriately defined as part of the drive mechanism, it also provides a structural component and is attached to other components of the frame  34 . 
     The drive mechanism  42  includes the lead screw  74  and a controllable drive motor  80 . The drive motor is mechanically coupled by way of a transfer assembly  82  such as a pulley and belt combination. Operation of the motor  80  and the drive mechanism  82  operates a correspondingly attached to the drive interface  84 . The drive interface  84  is driven by the drive assembly  82  and is provided with threads which correspond to the thread structure of the lead screw  74 . Transfer of energy from the motor  80  to the drive mechanism  84  causes relative motion of the frame  34  to which the drive mechanism  42  is attached along the lead screw  74 . 
     A controller  90  is coupled to the drive motor  80  over line  92 . A limit detector  94  in the form of a limit switch or other switch device positioned proximate a portion of the movable frame such as a detection plate  95  is coupled to the controller  90  over line  96 . The limit switch detects an upper limit  98 . Such limits may be in the form of structural features such as bumps or the protrusions or may be indicia  99 , gaps, colors, or magnetic strips or other devices which can be used to detect various limits, the sensor  94  along with the flow meter helps in detecting the lower limit  100  of the frame travel. The combination of the limits switch  94  and the sensor and flow meter detecting the upper and lower limits  98 ,  100  is intended to be broadly interpreted. These limits provide upper and lower boundaries which will be detected and communicated to the controller  90  to limit travel of the movable frame  34  and corresponding components upwardly and downwardly relative to the carriage and the adjustment screw driving therethrough. The location of the limit switch  94  may be varied for the best results. 
     A heated water system  106  controllably provides heated water to the extraction assembly  30 . The heated water system is controlled, at least in part by being coupled to the controller  90  over line  108 . The heated water system  106  is generally known in the art and may provide a variety of controllable features to control the amount of water dispensed, the timing of water dispensing, the temperature of water dispensed, the pressure of the water dispensed, and other features. A dispense line  110  is coupled to and communicates with the heated water system  106  to deliver water from the heated water system  106  to the brew chamber  46 . 
     It should be noted that the present disclosure may refer to coffee an espresso in reference to beverage making substance throughout the description in the interest of clarity and simplicity. It will be understood, however, that any form of beverage making substance may be used to produce a beverage and the term coffee or beverage making substance is intended to be broadly interpreted. This broad interpretation is also intended to include, but is not limited to, beverage substances including but not limited to, coffee, tea, herbs, botanicals, liquid beverage concentrate, ground, pulverized, rough cut, whole, powdered beverage concentrate, flaked, granular, freeze dried or other forms of materials including, but not limited to, liquid, gel, crystal or obtain a beverage or other food product or any other forms of beverage substance or food products. 
     Terms including beverage, brewed, brewing, brewing substance, brewed liquid, and brewed beverage as may be used herein are intended to be broadly defined as including, but not limited to, the brewing of coffee, tea, and any other beverages. This broad interpretation is also intended to include, but is not limited to, any process of dispensing, infusing, steeping, aerating, reconstituting, diluting, dissolving, saturating or passing a liquid through or otherwise mixing or combining a beverage substance with a liquid such as water without limitation to the temperature of such liquid unless specified. While a heated liquid is referred to herein it should be understood that reference to temperature is provided by way of illustration and not limitation and should be broadly interpreted. It should be understood that a beverage may be made to accommodate a recipe using heated, unheated, chilled or liquid within any range of temperature. Also, the volume or quantity of the beverage making substance used in the system or the beverage produced by the system is intended to be broadly interpreted and not limited to that as specifically disclosed and includes serving sizes ranging from single cup to multiple cup containers or low volume shots. 
     With further reference to  FIGS. 2 ,  3 ,  5  and  8 , a variety of operating positions and conditions for the extraction assembly  30  are shown. In  FIG. 2 , the extraction assembly  30  is positioned for receiving a quantity of brewing substance  114 . As shown in  FIG. 2 , the brewing substance has been dispensed from a grinder through the conical chute  60  and through a mouth  116  of the brew chamber  46 . As shown, the first piston  52  is positioned outside of the brew chamber so as to prevent interference when dispensing ground coffee through the chute  60  and into the brew chamber  46 . The position also may assist in preventing accumulation of ground coffee on the first piston  52 . 
     As shown, the second piston  56  is positioned in a lower portion  120  of the brew chamber. A shoulder  122  is positioned on the lower portion  120  of the brew chamber so as to provide an interface between the second piston  56  to limit travel of the piston downwardly through the brew chamber. A stem  124  of the second piston extends downwardly through an opening  126  in the bottom of the brew chamber defined by the shoulder  122 . A sealing gasket  128  is provided between the shoulder and piston so as to prevent leakage there between. Beverage brewing substance  114  dispensed into a cavity  130  defined by the inside surface  132  of the walls  134  of the chamber  46  rests on the upper face  140  of the second piston  56 . In the position shown in  FIG. 2 , the frame  34  is in grinding position allowing transfer of grounds to the brew chamber  46 . In one embodiment the motor  80  is a controllable DC drive motor which can be controllably operated on, off, or at a variety of intermediate speeds. When not operated, the frame  34  ceases movement along the lead screw  74  and sits idle unless operated by the controller  90 . 
     Progressing to  FIG. 3 , the drive mechanism  42  is operated to move the frame  34  carried on the lead screw downwardly along the brew chamber  46  so that the first piston  52  is engaged in the cylindrical cavity  30  of the chamber  46 . Engagement of the face  142  of the first piston  52  against the brewing substance increases the compacting force applied to the brewing substance  114  in the cavity  130 . It should be noted that the second piston  56  is carried against the shoulder  122  upwardly in a stationary dead stop position. As such, compaction force is driven against the second piston providing sealing of the second piston against the shoulder. 
     With reference to  FIGS. 1 and 4 , a sealing structure such as a compressible gasket, o-ring or other device  150  is carried in a perimeter annular channel formed on an outside perimeter of the first piston  52 . The gasket  150  is made of a compressible material. A leading edge  154  carried on the piston  152  is movable relative to a sleeve  156  carried on the outside of the piston. Compaction of the brewing substance  114  by the face of the piston  142  causes relative motion of the leading edge  54  against the sleeve  156 . This relative motion causes compression of the gasket  150  in the annual grove there between. 
     Compression of the gasket  150  does not occur during the initial movement of the piston  52  into the chamber  46  helping to reduce wear on the gasket and prolong its life. In this regard, a pair of first and second springs  170  and  172  are carried on a shaft  174  of the piston. When the piston  52  is first introduced into the brew chamber by movement of the frame  34 , the springs  170 ,  172  are relaxed and not compressed. As such, there is generally nominal force of the first spring  170  against the sleeve  156 . As such, there is little if any compression of the gasket  150  outwardly from the annular channel  152 . There is nominal engagement between the gasket  150  and the inside surface  132  of the walls  134  of the brew chamber. This facilitates improved wear characteristics and operation of the extraction assembly. While there may be some engagement between the gasket  150  and the inside surface  132  of the cavity  130 , this merely provides a wiping function which may provide improved sealing when the gasket  150  is compressed. 
     Further movement of the carriage upwardly causes the slight compression of the second spring  172 , having a lower spring constant, to initially start to compress as the face  142  of the piston contact the brewing substance. This tends to create a “soft seal” slightly compressing the o-ring. This results in an initial compaction force or packing pressure on the brewing substance. This soft seal and initial packing pressure allows the grains in the ground brewing substance to shift and position to provide some degree of uniformity in the distribution and compaction of the brewing substance. 
     Continued movement of the frame down along the lead screw causes further compaction and compression of the first spring  170 . Compression of the first spring  170  creates forces against the sleeve which further compresses the gasket  150  which causes the gasket to bulge outwardly against the inside surface of the brew chamber and creates a tighter seal. A packing pressure of approximately 40-50 pounds may be used for the compaction of the brewing substance  114 . The spring constant associated with each of the two springs  170 ,  172  can be specified so that desired compaction force against the brewing substance is achieved. Once the frame  34  is moved downwardly to fully engage the first piston  52  to a predetermined packing pressure, water can be dispensed in to the chamber under pressure to start the extraction process. 
     A sensor or detector  200  is provided on the extraction assembly to detect the conditions of the assembly during the brewing process. In this regard, the sensor  200  can be used to detect a variety of conditions associated with the compaction process just described. The sensor can be provided in a variety of embodiments such as optical, physical pressure detecting, relative movement, proximity, or other types of detectors. Also, the sensor may be positioned in one of several positions or multiple sensors may be used to provide difference sensing parameters or multiple sensing parameters to provide redundancy. 
     As shown in the Figures, a proximity detector  200  is carried on the frame. The proximity detector detects the relative motion of the first piston  52 . The proximity detector is coupled to the controller over line  202 . Once a predetermined condition is achieved, the proximity detector  200  detects this condition and communicates the information to the controller. The controller then stops further operation of the drive motor  80  thereby stopping movement of the carriage  38 . Ceasing operation of the motor  80  ceases movement of the frame  34  thereby creating a stopped or parked condition. The stopped position of the frame provides a relatively stable position for the brewing process. The sensor  200  (or multiple sensors) may be used to continue to monitor the condition throughout the brewing process. In this regard, if brewing substance shifts during the brewing process the change in compacting force can be detected and the motor  80  can be operated to adjust the frame appropriately. Continued monitoring may be used to improve the quality and continuity of the brewing process including the potential for shifting or change of the brewing substance or other brewing conditions. 
     Once the brewing substance  114  appropriately compacted in the brew chamber  46  between the first and second pistons heated water can be introduced through the inlet lines  220 . Heated water enters through the second piston  56 . A filter structure  222  (see  FIG. 4 ) carried on the first piston  52  allows beverage to pass through openings in the filter  224  and flow through the drain path  226 . Espresso  228  flowing through the drain path is moved upwardly through the first piston  52  and out through the dispensing line  230 . The espresso brewing process operates using pressurized water from the heated water system  106 . Generally, the pressure is sufficient to drive the espresso beverage upwardly through the drain path  226 . 
     The flow meter count is monitored to determine the end of the brew cycle. This signal of the brew cycle completion allows the frame to change direction of movement along the lead screw  74 . As the frame  34  moves upwardly, the reverse of the compaction cycle occurs with regard to the first piston  52 . The pressure is relieved from the springs  170 ,  172  ultimately allowing decompression of the gasket  150 . The decompressed gasket allows the first piston to smoothly disengage from the inside surface  132  of the brew chamber. 
     As the frame progressively moves downwardly, the stem  124  of the second piston  56  disengages the lower beam  66  of the frame  34 . As the frame continues to travel upwardly, the shaft  124  bottoms out against the recess  240  causing the piston head to disengage from the shoulder  122 . Further upward movement of the frame  34  causes relative motion of the piston  56  in the cavity  130  to move the spent brewing substance or “puck”  246  upwardly towards the mouth  116  of the chamber  46 . The puck in this condition is a somewhat moist relatively drained form of brewing substance. Some moisture allows the puck of material to retain the puck-like shape which facilitates convenience handling. As shown in  FIG. 5 , the piston  56  has been moved to a position generally co-planar with the mouth  116  of the chamber  46 . 
     At this point, reference is made to the enlarged view of  FIG. 7  as taken from  FIG. 5 .  FIG. 7  shows the cam follower  68  in the cam slot  70  which has generally followed a straight line path downwardly along the cam plate  62  from a position as previously shown in  FIG. 3 . At this point, the cam follower travels along an angled portion  248  of the slot causing the chute/wiper  60  to which the cam follower  60  is attached to pivot about the pivot point  260 . Pivoting of this structure  60  causes a blade portion  262  to sweep across the face  140  of the second piston  56  thereby ejecting or disposing of the puck  246 . Blade  262  also tends to wipe or remove material from the face  140 , thereby further enhancing the cleaning aspect of the present extractor assembly  30 . After the puck  246  is ejected, the frame  34  is driven by the motor  80  upwardly to a position as shown in  FIG. 2  which readies the assembly for the next brew cycle. 
     In use, the extraction assembly  30  starts as shown in a position in  FIG. 2  to receive brewing substance  114 . The frame  34  driven by the drive mechanism  42  travels downwardly along the lead screw  74  so that the first piston  52  engages and starts to compact the brewing substance  114  against the second piston  56 . As described, multiple springs  170 ,  172  are provided and associated with the first piston  52  to provide a seal by slightly compressing the gasket  150  between the sleeve and piston&#39;s head. The compression of the gasket  150  causes it to bulge slightly outwardly to form a tighter seal between the compressed gasket and the inside surface  132  of the chamber. 
     At a predetermined level of compaction force, the sensor  200  communicates with the controller  90  to stop operation of the motor  80  thereby stopping movement and compression or compaction of the brewing substance  114 . After the sensor indicates that the compaction is at a predetermined level and movement of the frame  34  should stop, the heated water system  106  is controlled to dispense water through line  110  to the chamber  46 . 
     As an additional matter, the chamber  46  can be provided with a heating element  300  which can be coupled to the controller  90  over line  302 . The heating element  300  can be wrapped on the outside of the chamber, embedded in the chamber or otherwise associated with the chamber so as to provide controllable heating energy if needed to the material of the chamber wall  134 . The ability to provide controlled heat to the chamber helps to maintain the temperature of the brewing process and prevent dissipation of the heat from the heated water. Controlled heating may be useful to help maintain a predetermined preferred brewing temperature. If the characteristics of chamber  46  are such that heat energy in the water would transfer to the wall material  134 , it may reduce the temperature of the water to an undesired level thereby altering the expected brewing characteristics. As a result, additional heat can be controllably provided to maintain the chamber wall  134  at a desired temperature to prevent this heat transfer. 
     As the water flows through line  110  into the cavity  130  filled by the compressed brewing substance  114 , a brewing process occurs often referred to as “espresso brewing”. The espresso beverage is filtered through the filter structure carried on the first piston  52  and flows through the drain passages for dispensing from the dispense line  230 . 
     In the upwardly most or “home position”, a limit switch or sensor  94  operates (see  FIG. 9 ) to prevent over travel of the frame throughout the brewing process. In the downwardly most or brewing position, the compacting sensor, and flow meter signals prevents over travel of the frame throughout the brewing process. 
     While the present disclosure may be susceptible to embodiment in different forms, there is shown in the drawings, and herein will be described in detail, embodiments with the understanding that the present description is to be considered an exemplification of the principles of the disclosure and is not intended to be exhaustive or to limit the disclosure to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. 
     While this disclosure has been described as having an exemplary embodiment, this application is intended to cover any variations, uses, or adaptations using its general principles. It is envisioned that those skilled in the art may devise various modifications and equivalents without departing from the spirit and scope of the disclosure as recited in the following claims. Further, this application is intended to cover such departures from the present disclosure as come within the known or customary practice within the art to which it pertains.