a general diagrammatic illustration of an extractor assembly 30 is shown in fig1 . 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 fig2 ). 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 fig2 , 3 , 5 and 8 , a variety of operating positions and conditions for the extraction assembly 30 are shown . in fig2 , the extraction assembly 30 is positioned for receiving a quantity of brewing substance 114 . as shown in fig2 , 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 fig2 , 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 fig3 , 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 fig1 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 fig4 ) 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 fig5 , 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 fig7 as taken from fig5 . fig7 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 fig3 . 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 fig2 which readies the assembly for the next brew cycle . in use , the extraction assembly 30 starts as shown in a position in fig2 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 fig9 ) 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 .
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 .