This application claims priority from Australian Patent Application Number AU2020904817 and Australian Patent Application AU2021221718, the contents of which are incorporated by reference.
The present invention relates to a tamp and portafilter holder.
A coffee machine generally has a grinder for grinding coffee beans and a grinder chute to convey the ground coffee to a portafilter fitted into a portafilter holder of the machine, where the coffee is tamped into a puck by a tamper, prior to injection of steam and/or water which filters through the puck and is extracted into a cup positioned beneath the portafilter.
Consistency of puck preparation is important for consistent extraction. This requires an even distribution of grounds, consistent tamping pressure for each puck and dosage amount of coffee grounds among other variables.
An uneven distribution of coffee grounds leads to a compacted puck of coffee grounds having uneven coffee ground spacing, density, and/or thickness, potentially leading to a phenomenon referred to as “channeling”, where the steam and/or water preferentially travel along some paths through the puck, leading to uneven coffee extraction and unfavorable aromas in the extracted coffee beverage.
According to an aspect of the invention, there is provided a tamp including a body and a tamping face carried by a base of the tamp, the base and body being arranged for relative movement in an axial direction during a tamping operation to compress and expand under action of a bias element, wherein the tamp includes a rotation mechanism to translate the relative axial movement of the base and body into rotational movement of the base.
In one embodiment, the rotation mechanism causes rotational movement of the base relative to the body during tamping and reverse rotational movement after tamping.
In one embodiment, the rotation mechanism includes a series of internal ramps in either the base or body that engage with corresponding opposed structure in the other one of the base or body, sliding engagement of the ramps with the structure causing the rotational movement of the base.
In one embodiment, the body includes a coupler formed of two support members that each carry a pivot and a rotational coupling in spaced vertical relation, wherein the pivots project laterally of the tamp a greater distance than the couplings.
In one embodiment, the support members define a clearance space therebetween to provide clearance for a grind chute.
In another aspect, there is provided a portafilter holder for positioning a portafilter under a tamping unit of a coffee grinding machine, for receipt of the coffee grounds, the portafilter holder including a dock to receive the portafilter and a retention member to hold the portafilter in the dock.
In one embodiment, the retention member is biased into engagement with the portafilter.
In one embodiment, the retention member is resiliently biased.
In one embodiment, the portafilter holder includes entry ramps to engage with tabs of the portafilter to self-align the portafilter during insertion and to lift the tabs clear of the clasp and into the dock.
In one embodiment, the dock includes support surfaces which are vertically offset to accommodate vertically offset tabs of the portafilter.
In one embodiment, the portafilter holder includes a sensor to determine if the portafilter is loaded into the portafilter holder.
In another aspect, there is provided a machine for delivering coffee grounds to a portafilter, the machine comprising: a grinder for grinding coffee grounds into the portafilter; a tamping mechanism for tamping coffee grounds in the portafilter, and a portafilter holder, as described above, to hold the portafilter under the tamping mechanism during tamping.
In one embodiment, the tamping mechanism includes the above described tamp.
In another aspect, there is provided a machine comprising: a grinder for grinding coffee grounds into the portafilter; a tamping mechanism including a tamp, as described above, for tamping coffee grounds in the portafilter, and a portafilter holder to hold the portafilter under the tamping mechanism during tamping.
The invention is more fully described, by way of non-limiting example only, with reference to the following drawings, in which:
In
The mechanism 11 carries a tamping force control assembly 15, which is formed of a housing 16 which houses a biasing element 17 in the form of a compression spring 18. In some implementations, the biasing element 17 may be in the form of other types of springs, such as a tension spring. It is preferable to have the biasing element 17 pre-loaded/pre-tensioned (i.e. the biasing element is not in its natural position when installed) so that: the tamping force can be more precisely controlled; the stroke length of the tamping mechanism is decreased, which allows the height/size of the machine to be reduced to provide a more compact machine; the required rotation of the lever 6 by the user is reduced; and less force is required by the user to tamp the coffee grounds. It is preferable to have one or more biasing elements 17 acting on the linkage 7 so that the tamping force applied to the ground coffee is controlled.
More particularly, the pre-tensioned or pre-loaded biasing element 17 provides the following benefits as compared with a non-pretensioned (non-preloaded) biasing element 17: a lower biasing rate (a lower spring rate in the current embodiment) so as to give a more consistent and accurate tamping force over the stroke length; and a reduced compression distance for the coffee grounds over the stroke length of the mechanism 11 to achieve predetermined tamping force, which allows reduced rotation of the lever 6 by the user and reduced force required by the user to rotate the lever 6 to tamp the coffee grounds which, as mentioned above, can reduce the height and size of the machine 1 to provide a more compact design
A sensor 20 is provided which includes a connecting rod 19 and the relative position of the connecting rod 19 may be used to monitor the distance travelled by the tamping mechanism 11. When the coffee puck is tamped/pressed, the biasing element 17 is compressed, which results in movements in the connecting rod 19. It should be noted that the sensor 20 with a connecting rod 19 is merely an example of means for measuring distance travelled by the tamping mechanism 11.
A grind chute 21 extends from the grinder 10 which, when activated, delivers ground coffee along a flow path 22 and out through a tamp chute 23, to a location centrally of the portafilter holder 7, directly beneath the tamp chute 23. The tamp mechanism 11 also travels within the tamp chute 23 between raised and tamp positions.
The rest position of the tamp 14, when the mechanism 11 is raised, is out of the flow path 22 of the ground coffee so as not to obstruct the delivery of coffee through the tamp chute 23.
The grind chute 21 is positioned directly above and within a top region of the tamp chute 23 in substantial alignment with a centreline 24 of the tamp chute 23. The mechanism 11 is in a raised position such that a face 25 of the tamp 14 and mechanism 11 is rotated clear of a lower end 26 of the chute 21.
The mechanism 11 includes a linkage 30 connected to the shaft 12 at one end 31, for fixed rotation with the shaft 12. The tamp 14 includes a base 27, a body 28 and a coupler 29 to connect the tamp 14 to the linkage 30 by a rotary coupling 32 which allows the tamp 14 to rotate when moved out of and returned to the rest position.
The tamping unit 2 has an internal housing 33 extending upward from the tamp chute 23. The housing 33 assists in containing coffee grounds as they travel toward the tamp chute 23. The housing 33 has guide structure 34 in the form of slots 35 that guide the tamper 14 as it is rotated and moved out of and returned to the rest position by the linkage 30.
The mechanism 11 is in the tamping position, where the tamp 14 has been lowered through the tamp chute 23 of the tamping unit 2 to sit inside the basket 42 for tamping the coffee grounds into a puck (also not shown for clarity).
Referring now to
A rotary position sensor 51 is also provided which receives input from a cog 52 that engages the gear 50 and allows the position of the lever 6 to be monitored by way of the relative rotational position of the shaft 12, which also provides an indication of the corresponding position of mechanism 11. The rotary sensor 51 may also be placed in alternative locations and may, for example, be used to instead monitor rotation of the gear 50; the shaft 12; damper 53; or the lever 6
A damper 53 is also shown, which provides rotational resistance through a cog 54 which also engages with the gear 50.
The sensor 20 is preferably a linear position/displacement sensor, also known as a VR sensor, although any other suitable form of linear position sensor may be used. Feedback from the sensor allows the height of the tamp 14 to be ascertained when the mechanism 11 is extended to the tamping position, at the end of the downward stroke, and this in turn reveals the tamp depth (i.e. height of the coffee puck). The rotary position sensor 51 may also be used to provide information on the linear extension of the mechanism 11 as the measured rotational position of the shaft 12 is directly related to the degree of extension of the mechanism 11. The user can be provided with this information to understand where the tamp 14 is located during and/or after tamping. The tamp depth will vary depending on the dosage of coffee grounds which needs to be tamped. In an overdosed condition, the extension of the mechanism 11 will be reduced when the linkage 30 is fully extended, leading to a reduced tamp depth (i.e. increased puck height) while in an underdosed condition, the mechanism 11 will be further extended, resulting in a greater tamp depth (i.e. reduced puck height). More particularly, in an overdose condition, when the tamp travel distance is reduced the extension of the mechanism 11 is reduced, as such the compression of the biasing element 7 is also reduced, as detected by the sensor assembly 20 (via the connecting rod 19).
Following activation of the grinder 10, the lever 6 can be rotated back or biased toward the home position to move the protrusion 62 out of engagement with the switch 63, as shown in
The mechanism 11 includes an articulated linkage 30 connected to a shaft 12, with a lever 6 in a home position and the mechanism 11 in a raised position holding a tamp 14 clear of grind chute 21. The tamping control force assembly 15 includes compression springs 64 mounted on posts 65 attached to fixed structure 66 of the tamping unit 2. The springs 64 act between end washers 67 and a carriage 68 which supports the shaft 12.
The shaft 12 is coupled to the lever 6 by a U-shaped section 69 which allows rotational movement of the lever 6 to be transmitted to an end extension 70 of the shaft 12 while providing clearance for the springs 64 of the tamping force control assembly 15 positioned inside the U-shaped section 69.
The end extension 70 is coupled to a limited movement connector 71 which includes a rocker 72 that rotates about a pivot 73 connected to the fixed structure 66. One end 74 of the rocker 72 is rotatably mounted to the extension 70 and the other end 75 of the rocker 72 is provided with an elongate opening 76 that receives a follower 77. The follower 77 slides up and down a vertical channel 78 provided in a bracket 79 which is also fixed to the structure 66. The follower 77 is shown at an upper end 80 of the channel 78 when the lever 6 is in the home position.
Referring now to
Further rotation of the lever 6 causes the mechanism 11 to move to the tamping position, where the linkage 30 is extended, as shown in
Referring now to
The mechanism of
A lever 6 is shown in the home position, where the linkage 30 is raised and the rollers 92 rest at a lower end 95 of the slots 91.
The tamp 14 has an identical pivot 82 on another side which is received in a matching slot 35 in the housing 33, at an opposite side of the tamp 14.
The pivots 82 track the path of the slots 33 and additionally or alternatively, the coupling 32 can also track the slots 33 when the mechanism 11 is raised and lowered such that the tamp 14 rotates back to a tilted orientation when the pivots 82 move through the curved top parts 98 of the slots 33, to a position shown in
Referring to
The rotary coupling 32 connects a remote end 99 of the arm 86 to a side of the tamp 14 so that the tamp 14 rotates about the arm 86 as the tamp 14 is raised along the guide slot 25, thereby tilting the face 25 of the tamp 14 away from the end 43 of the chute 21. The other arm 86 is connected in the same manner, as shown in
In
In
As mentioned above, the rotary sensor 51 may be used to monitor the extension of the mechanism 11 and the resulting tamping position, in order to determine the tamp depth. However, the tamping position and the tamp depth can instead be measured by a sensor 20 monitoring the vertical height of the rack 85, to provide a direct VR or linear distance reading.
For completeness,
The mechanism 11 is shown in a lowered tamping position, where the tamp 14 sits inside a basket 42 of a portafilter 40. The mechanism 11 includes a linkage 30 in the form of an arm 86 connected to a rod 102 of an actuator 13 in the form of a linear drive shaft 103 which moves up and down through support 104.
In
More particularly, the second linkage 105 is connected to the tamp 14 via pivot 82 and the linkage 30 is connected to the tamp 14 through the rotary coupling 32 which is intermediate tamp face 25 and the pivot 82, to allow the tamp 14 to be pivoted between different tilted orientations as the linkage 30 is moved in a linear direction relative to the hinged second linkage 105.
Linear upward movement of the drive shaft 103 results in the tamp lifting and rotating clear of the lower end 43 of the grind chute 21, while linear downward movement of the shaft 103 causes the tamp to rotate back to the tamp position shown in
The mechanism 11 is shown as including a linkage 30 in the form of a rack 85 which is driven by a pinion 90 attached to a drive shaft 12. The rack 85 is connected to a tamp 14 via an arm 86 and a rotary coupling 32 such that a tamp 14 is moved up and down in a linear manner indicated by directional arrow when the rack 85 is lifted and lowered by rotation of the shaft 12.
The shaft 12 is operated by a lever 6 through a clutch 60. The clutch 60 includes an annular slot 109 which receives a pin 110 that projects from fixed structure 66 to allow the clutch limited rotational movement in unison with the lever 6.
It may be appreciated the clutch 60 may be used in combination with the other examples of machines 1 described above.
The relative position of the lever 6 and tamp mechanism 21 can be monitored by one or more different sensors, as required.
Alternatively, a rotary sensor 51 may be employed in the position shown in
As the lever 6 is pressed down, the mechanism 11 lowers the tamp 14 through an intermediate position shown in
At the end of the stroke, the rack 85 is in a lowered position and the tamp 14 is located in the tamping position shown in
Moving to
A second disc 115 is attached to the lever 6 and includes connection recesses 116 for receiving the connection members 113 of the first disc 112, to inhibit relative rotation between the first and second discs 115. The second disc 115 also includes bias elements 117. Preferably, the biased elements 117 are similar to the biased protrusions 114 but oriented in an opposite direction.
The clutch 60 also includes a clutch disc 118 with a central shaft receiving clamp 119 and a radial array of annular slots 120. The connection members 113 pass through the slots 120 which have an annular dimension sufficient to allow limited movement between the clutch disc 118 and the first disc 112 such that lifting the lever 6, for example, does not translate into any movement of the clutch disc 118.
The clutch disc 118 also includes two annular openings 121 to receive the biased elements 114 and 117 of the first and second discs 112 and 115, so that the first and second discs 112 and 115 are able to drive the clutch disc 118 and transmit torque from the lever 6 under pre-tensioned bias. The discs 112 and 115 in combination with the bias elements 114 and 117 thereby form a tamping force control assembly 15 to apply bias force during a tamping operation.
As may be appreciated from the above, an aspect of the invention is a machine 1 which, in one broad form, is a machine for delivering coffee grounds to a portafilter, the machine comprising: a grinder for grinding coffee grounds into the portafilter; a tamping mechanism for tamping coffee grounds in the portafilter along a path, the tamping mechanism comprising: a tamp comprising a surface for tamping coffee grounds; and a linkage connected to the tamp, wherein during a first portion of the path, the linkage causes the surface to orient in a first direction, and during a second portion of the path, the linkage causes the surface to orient in a second direction, wherein the first and second directions are different.
The invention also provides a machine for delivering coffee grounds to a portafilter, the machine comprising: a grinder for grinding coffee grounds into the portafilter; a tamping mechanism for tamping coffee grounds in the portafilter along a path, the tamping mechanism comprising: a tamp comprising a surface for tamping coffee grounds; a tamping actuator for moving the surface along the path, wherein during a first portion of the path, the surface is oriented in a first direction, and during a second portion of the path, the surface is oriented in a second direction, wherein the first and second directions are different.
The tamping mechanism moves the tamp through the first and second portions of the path between a rest position and a tamping position, where the surface is oriented in the first direction in the rest position, and in the second portion of the path the surface is oriented in the second direction for a tamping operation. In all the above examples, the linkage being is arranged to press a face of the tamp in an axial direction with respect to the portafilter during a tamping operation and return the tamp to a rest position between tamping operations along a non-axial path relative to the basket held in the portafilter such that the tamp does not obstruct delivery of the coffee into the chute when in the rest position.
The tamping mechanism rotates the tamp between the first and second portions of the path so that the tamp surface is oriented in the second direction for tamping coffee grounds during the tamping operation. In the above examples, the linkage returns the tamp to a rest position between tamping operations along a non-axial path relative to the portafilter such that the tamp does not obstruct delivery of the coffee into the portafilter when in the rest position.
The tamp is rotated in the rest position relative to the tamping position such that the tamp surface is oriented in the first direction which is angled away from the second direction whereby the tamp does not obstruct coffee grounds being delivered into the portafilter from the grinder.
Turning now to
The tamp has a base 27, a body 28 and a coupler 29 for connecting to the above described linkage 30. The coupler 29 includes support structure 122 that extends upwardly of the body 28. A transverse pin 123 provides a rotary coupling 32 for the tamp 14. A second pin 123 extends from an opposite side of the support structure 122 to provide a second rotary coupling 32.
A guide pivot 82 projects laterally of the tamp 14 in line with but in vertically spaced relation to an associated coupling 32. The guide pivots 82 extend laterally further from the support structure 122 than the couplings 32.
The support structure 122 is in the form of two spaced apart support members 124 which define a clearance space 108 therebetween.
The base 27 has a collar 126 which slides up and down along a cylinder 127 fixed to the body 28 with a fastening screw 128. A biasing element 129 is positioned between the body 28 and the base 27. The biasing element 129 is preferably in the form of a spring 130 which is positioned over the collar 126 and connected between the base 27 and the body 28.
The rotating mechanism 125 includes cam structure 131 which generates the rotational movement of the base 27 when the base 27 is moved axially or telescopically with respect to the body 28. The cam structure 27 is in the form of a series or ramps 132 and respective projections 133.
The base 27 further includes a side wall 134 which slides up and down an outer wall 135 of the body 28 and the body 28 has a locating flange 136 to support a seal 137 which seals against the side wall 133 during relative axial movement. The flange 135 also carries a retaining ring 138 to hold the seal 137 in place.
The base 27 includes a circular rebate 139 in the side wall 134 to receive an attachment skirt 140 which supports a tamping face 25 underneath the base 27.
The tamp 14 is shown in an expanded state. As may be appreciated, when axial load is placed on the tamp 14, during a tamping operation, the tamp 14 compresses as the base 27 moves toward the body 28. During that axial movement, the ramps 132 and projections 133 engage and slide along each other to cause rotation of the base 27.
After a tamping operation, the axial load is removed and the spring 130 urges the base 27 away from the body 28, which causes the camming action to be reversed. This causes the base 27 to rotate in a reverse direction as the tamp 14 returns to the expanded state as a result of the ramps 132 and projections 133 reversing to the original orientation.
The rotational movement of the base 27 helps to “polish” the puck during tamping and provide a more even distribution of coffee grounds. Simultaneously, any coffee grounds that may have adhered to the tamp face 25 can be dislodged, which helps to clean the tamp 14 which is beneficial as a build-up of coffee grounds on the tamp 14 may otherwise the formation of an ideal puck.
The relative rotation of the base 27 of the tamp 14 in both directions serves to self-clean the tamp 14 and remove coffee grounds off the face 25 of the tamp 14 both during and after the puck is formed as the tamp base 27 rotates relative to the body 28 during tamping and again after the tamping operation when axial load on the tamp 14 is removed.
Turning now to
The tamp 14 is shown as having only a single spring 130 to bias the base 27 away from the body 28 however additional springs or alternative biasing means may be used, as required.
The tamp 14 of
As shown in
The tamp 14 of any one of
As shown in
As better seen in
As seen in
Preferably, the tamp bias member 222 has a pre-tension to urge the tamp face 25 toward the rest position. More preferably, the tamp bias member 222 also has a pretension to urge the tamp face 25 toward the rest position, both in axial translation relative to the body 28, and in rotation relative to the body 28.
As shown in
In a preferred embodiment, the tamp 14 is sealed. An indicator 224 (as shown in
Referring now to
A dosing unit 2 is shown in
In
As described above with reference to
By independently guiding the pivots 82 and the couplings 32, the tamp 14 can be readily rotated into and out of the rest position without following a wrong path (e.g. the tamp 14 may otherwise be rotated in an opposite direction so as to block the grind chute).
For tamping, the coupling 32 is guided out of the upper portion 156 of the track 153, down to a vertically oriented lower portion 155 of the track 153. The pivot 82 is simultaneously guided out from the upper portion 157 of the track 154 and then down the vertical portion 155 of the track 154.
In that position, the tamp 14 is ready for tamping. A centre line 158 of the mechanism 11, taken through the centre of the shaft 12 and the coupling 32 is angled away from vertical indicated by vertical line 159, which assists in angling the face 25 of the tamp 14 more toward vertical when the tamp is lifted into the rest position and that in turn provides improved clearance so that tamp 14 does not obstruct the flow of coffee grounds during a dosing operation.
The use of dual tracks 153, 154 provides a benefit that each pivot point of the tamp 14 can be controlled independently for smooth motion and fast rotation when the mechanism is at a top of a stroke, to quickly move the tamp 14 into a rest position and away from obstructing the flow of coffee during the dosing operation.
A sensor 51 is used to detect the relative rotation and position of the shaft 12 during the tamping operation. The sensor 51 monitors the shaft rotation through a cog 52 which meshes with a control gear 50 attached to the shaft 12. The gear 50 has teeth 161 only over a limited section 162.
A damper 53 is provided under the sensor 50, as shown in
The damper 53 serves to reduce the speed of the tamping mechanism immediately before and after the tamping operation. This can help minimize mess such as may be caused by the tamp impacting the coffee grounds at speed on approach or by releasing from the puck at speed after the tamping operation, which could lead to the puck being loosened in the portafilter leading to poor coffee extraction.
The following is a description of the portafilter holder 7 and like parts to those described above will be designated with like reference numerals.
With reference now to
The portafilter holder 7 includes an access opening 167 and a dock 168 defined by top and bottom support surfaces 169, 170 that securely capture and hold the tabs 165 when the portafilter 40 is in the illustrated docked position.
Ramps 171 are provided either side of the opening 167 to guide the tabs 165 into the dock 168 and a retention member 172 is also provided to resiliently hold the portafilter 40 in the docked position. The retention member 172 is formed of two biased elements 173 which are preferably in the form of spring clips 174 although any other suitable gripping means may be employed, as required.
To load the portafilter 40 into the portafilter holder 7, the portafilter 40 is initially introduced into the opening 167 so that the tabs 165 engage the ramps 171. This assists in centering and aligning the portafilter 40. The handle 163 is then used to push the portafilter 40 against the biased elements 173, which separate to allow the insertion of the portafilter 40, after which the clips 174 close against the portafilter 40 to bias the portafilter 40 into the docked position.
Conventional bayonet type portafilters have vertically off-set tabs and the lower support surfaces 170 lead up to support surfaces 171a (as shown in
Turning now to
As may be appreciated, the portafilter 40 can be reliably positioned and held in the portafilter holder 7 using a single insertion action and there is no requirement to lift and rotate the portafilter 40, as is normally needed with bayonet style portafilters. This helps simplify use and reduces the overall design height of the portafilter holder.
As shown in
The retention member 172 preferably urges the body 180 of the portafilter 40 by exerting a retention force on the portafilter 40. The retention force is preferably parallel to the support surface 170. Further, the rear wall 176 preferably includes a portafilter detection switch 215 (as shown in
The retention member 172 preferably exerts the retention force by resiliently deforming from a position that interferes with a position of the portafilter 40 when the portafilter 40 abuts the rear wall 176. The tendency of the retention member 213 to resiliently deform back to the position urges the portafilter 40 against the rear wall 176. In another embodiment, the retention member 213 includes a spring (not shown) with a pre-tension to exert the retention force. Preferably, the holder 7 includes two retention members 172 located at opposite sides of the holder 7, and therefore the portafilter 40 when held by the holder 7. Preferably, the retention members 172 are located in a plane parallel to the support surface 170 but vertically below the support surface 170.
The system 200 includes a controller 201 and a motor status sensor 202, which provides information on either the current or the motor speed of the grinder, to indicate the presence of beans in the hopper and/or blockages.
The system 200 also includes a grinder module 202 which receives start and stop signals from the controller 201 and provides feedback to the controller 201 when the grind is complete.
A tamper module 203 is also provided to conduct a tamping operation and provide tamp position information to the controller.
Lastly, the system includes a user interface module 204 to facilitate user operation of the system. The interface module 204 provides the user with operational prompts and allows for the user to operate the grinder and conduct a tamping operation.
The system 200 is used to implement one or more of the dosage algorithms described below.
With various examples of the tamp mechanism 11 described above, the tamp position is monitored and during a tamping operation a tamp depth can be determined. The tamp depth information provides feedback for the purposes of determining the appropriate dosage of coffee grind into the portafilter 40. For example, if the position of the tamp 14 during the tamping operation is too high or low the grind can be changed so that the current and/or next dosage is adjusted accordingly.
Referring to
Step S101 represents an initial step of activating the grinder for a pre-determined grind, to produce a predetermined amount of coffee grinds. The predetermined amount of coffee grinds can be achieved by either using a pre-determined grind time or using a weight sensor to detect whether the predetermined amount of coffee grounds are delivered.
Once the grinder is activated coffee beans are ground in the hopper and transferred through the grind chute to the portafilter.
The tamp position is checked to be in the rest state at step S103, after which the tamp assembly is moved from the rest position to a tamp position at step S105. Tamping pressure is then applied to prime the tamp against the coffee grounds in order to form a coffee puck in the portafilter. The tamp state is recorded as primed at step 106 and the mechanism is also recorded as being in an extended state at step 107.
The total tamp depth is determined at step 109 by comparing the position information from when the tamp was in the rest state with the position of the tamp when the mechanism is in an extended state. A determination can then be made at step 111 as to any deviation between the tamp depth and an ideal depth.
If the deviation is smaller than a predetermined tolerance, no action needs to be taken and information can be provided to a user interface indicative of the ideal depth, as at step 115. However, if the deviation is greater than a predetermined tolerance, information can be provided to a user interface indicative of the polarity of the deviation, as per step 117. The dosage can then be adjusted for the current and/or the next use.
Regarding
In relation to the measured tamp depth, this can be determined based on feedback from any suitable measuring sensor. If a rotary sensor and a linear sensor are used, the depth may be provided by:
depth=d=P−x
θ: Tamp state signal from rotary sensor (preferably difference between primed tamp state and extended tamp state)
R: Length of the first member 36 (including the movements in the connecting rod 19 as detected by the linear sensor 20)
L: Length of the second member 37
P: Ideal tamp depth
In one example, a preferable predetermined ideal tamp depth may be 6.75±0.5 mm. Tamp depths may be characterised as either underdosed or overdosed, depending on the amount of ground coffee deposited in the portafilter. An underdose such as shown in
As seen in
For a typical dosage operation, the adjustment calculation may be performed in auto mode using the linear relationship between the tamp depth and a pre-determined volume of a compressed coffee puck:
Volume [%]=c1* tamp depth [mm]+c2
In one embodiment the values for c1 and c2 are −0.0638 and 1.4326, respectively, where the values for c1 and c2 may vary based on the geometry of the basket (e.g. single or double basket, basket with different diameters).
Using this relationship, the processor determines how much more or less volume is required in current and/or future coffee pucks. The adjustment to the grind may then be provided by the linear relationship between volume and grind time, which may be determined by the processor by dividing the determined volume by the current grind. The current and/or next grind is then determined by the reciprocal of this gradient.
The tamp depth calculation for a mechanism with an articulated linkage can also be derived in the following manner:
Forward Kinematics and Denavit—Hartenberg (DH) Parameters
The mechanism 11 can be considered as a configuration of a two Degree-of-Freedom (DoF) planar manipulator on an x and y coordinate frame. The figure below shows coordinate frames at different joints. Specifically, [x0, y0], [x1, y1], [x2, y2] represents the coordinate frame at the joint of the shaft 12, the joint of the first member 36 and the second member 37, and the rotary coupling 32 respectively.
That leaves us with the following equation to calculate the y coordinate.
y=l
1 sin(q1)+l2 sin(q1+q2) (1)
We know the offset between the end effector and origin axis to be x=c1 (It is negative based on the orientation above). As a result, we can get an equation to find q2 based on any joint angle for q1:
x=c
1
=l
1 cos(q1)+l2 cos(q1+q2) (2)
To derive a single equation to determine the y coordinate end effector, we can substitute q2 into the equation for y:
In the preferred embodiment, the spring is located on the first member 36, so l2 a constant value, the only variables are l1 and q1. As previously discussed, a sensor 20 is provided which includes a connecting rod 19 and the relative position of the connecting rod 19 may be used to monitor the distance travelled by the tamp (l3).
It should be noted that if the biasing element 7 is located on the second member 37, l2 would be variable and l1 would be a constant value. If the biasing element 7 is not in both of the first member 36 and the second member 37, l3 may be eliminated (=0) from all equations.
The linear relationship of the distance monitored by the sensor 20 (l3) and l1 can be:
l
1
=l
member36
−l
3[SWS]
This yields the equation:
Alternatively, the relationship of the first member 36 and the distance monitored by the sensor 20 can be non-linear. This relationship can be derived from trigonometry.
L
1
2
=l
4
2
+l
5
2
Wherein l4 is a constant value and l5 represents the distance monitored by the sensor 20.
l
5
=a
1
−l
3
The above two equations will yield a non-linear relationship between y and l3.
To simplify the calculations, we can assume at the extended state we assume q1=90°; q2=90°, which means we can use the above equation to calculate tamp height based on the linear sensor 20 without measurements from the rotary sensor.
In this way, the linear relationship between y and l3 can be yielded:
y=c
2
−l
3
Derivation 2—Denavit-Hartenberg (DH) parameters (an alternative derivation that is unique in itself. DH is normally used for robotics/robotic arms. It also derives the rotation and point of each of the links at any positions and can be used to derive the force equations too)
With q2 found (from equation (1) & (2)), we can now get the Denavit—Hartenberg (DH) parameters for the mechanism. To test these two equations, the values for l1, l2, q1 and q2 are put into a DH calculator to find the transformation matrix from one coordinate frame to the next.
Wherein y is the movements of the first member 36 (or the second member 37 if the biasing element 7 is located in the second member 37).
q: Rotation about z-axis
l: Distance on the z axis
b: Length of each common normal (Joint offset)
a: Angle between two successive z-axes (Joint twist)
This dosage algorithm is based on two main parts: the tamp reading and the current grind. When a user tamps, the height of the tamp is measured and if the puck is not at the ideal height the length of time for the current and/or next grind is updated accordingly. If the above described system 200 detects an underdosage, the grind will increase and if an overdosage is detected, the grind will decrease.
During a grinding cycle, if the hopper runs out of beans and/or the grinder is blocked and the grinder continues until it finishes its set time, the user will tamp and receive an underdose reading (assuming it would have been an ideal dosage otherwise). This results in the algorithm trying to overcompensate by adding more time to the current and/or the next grind. When the user fills up the hopper again and tries to grind, they will receive an overdose in the current and/or the next tamping operation as the algorithm tried to compensate for the underdose that should have been an ideal dose.
This problem gets worse if the dosage was going to be an overdose, but the hopper ran out of beans and/or the grinder is blocked during a grinding cycle. If the height reading was an underdose again, the grind would update itself to a severe overdose.
By having a sensor to detect beans in the hopper and/or any potential grinder blockage, the grinder can be stopped if no beans are present and/or the grinder is blocked. This stops the grind from being completed unless there are beans present and updates the grind for the algorithm accordingly. This way, when the grind is completed the algorithm will adjust correctly so that the current and/or the next grinding cycle yields an ideal dosage. This removes any chance of errors in the algorithm caused by running out of beans.
An optional or an alternative step is that the grinder status can be checked prior to grinding so as to allow the user to i) refill the hopper if the hopper is empty; and ii) check the grinder if the hopper is blocked.
This method relies on the electric current drawn by the grinder. The current when beans are present will be greater than the current when no beans are present, as shown in the graph above. The threshold to turn off the grinder will be slightly above the ‘no beans’ current draw. If the current is higher than the current when beans are present, the grinder is blocked and will be turned off.
A similar comparison to the above can be based on the motor speed of the grinder, which differs depending on whether there are beans in the grinder, as indicated by the graph below.
If both the hopper and portafilter are detected the grinder is enabled at step S133 and a grinder LED is illuminated to indicate the grinder is on at step S134. The user is then able to start the grind at step 135 such as by lifting the lever of the machine.
A check is then conducted to determine if there are beans in the hopper at step 136. If the hopper is empty the grinder is turned off at step S137 and the grinder LED is put to flash at step 138. A check is made at step S139 to ascertain if the user has removed the portafilter.
If the portafilter remains in the portafilter holder it is likely the user has re-filled the hopper with beans so a check of whether the user has restarted the grind is made at step 140. If the user has restarted the grinder, the actual grind time up until the grinder was stopped needs to be recorded and the remaining grind time needs to be updated at step S141, after which the process reverts to step S135.
If the user does not restart the grind, a pre-set time is checked at step S142, after which the actual grind is recorded at step S143 and an update of the grind time is made at step 144, after which the algorithm ends at step S145.
If the user removes the portafilter after an interrupted grind, a timer is started at step S146. If the pre-set time is determined as not having been reached at S142, and the portafilter is detected at step S147 as having been inserted back in the portafilter holder, the process reverts to step S140. Alternatively, if the pre-set time has passed, steps 143 and 144 are undertaken to update the grind.
It is of course important that the grinder not be operated if there is no portafilter in the portafilter holder. As such, if no portafilter is detected at step S148, the grinder is stopper at step S149, the grind is reset at step S150 and the grinder is disabled at step S151, followed by the grinder LED being turned off at step S152.
A similar process of turning the grinder off is undertaken if no hopper is detected at step S153. If a hopper is detected, as well as a portafilter at step 148, the process reverts to a check of whether the hopper is empty at step 136.
At step 154, the position of the lever is checked. If the lever has been moved from its home position the grinder may be stopped through the process of step 137. If the lever position is unchanged, a check is made at step S155 as to whether the grind is finished.
If the grind is complete, the grinder is stopped at step S156. The grind LED is turned off and a tamp LED is turned on, indicating the system is ready for the tamping operation.
Step S158 indicates the tamping operation. The grind is updated after the tamping operation, followed by the process ending at step 145.
Another important step in the above process is to maintain a check on any blockage in the grinder. This is done at step S159. If a blockage is detected, the grinder is stopped at step S160 and LED lights on the user interface are made to flash at step S161 to indicate the blocked state of the grinder. If the grinder is not blocked, the system can continue to monitor the status of the hopper and portafilter at steps S136, S148 and S153.
One of the error scenarios for the manual tamp system is that the user can incorrectly select the wrong basket size setting for dosing operation. This would i) update the next grind for the next cycle incorrectly; and ii) add incorrect grind time to the current cycle.
In the case where a single basket setting for dosing operation has been selected but a double basket is used, the resultant volume of coffee provided into the portafilter will be severely underdosed. To correct the error, a significantly longer grind is needed.
Conversely, if a double basket setting has been selected but a portafilter with only a single dose basket is used, the amount of coffee provided into the portafilter will be severely overdosed and require the portafilter to be removed and cleared of the excess coffee.
A similar problem exists if two or more grinding cycles are conducted on one portafilter. For example, a first grinding cycle and a tamping operation is completed, the portafilter with coffee grounds delivered from the first grinding cycle is removed, reinserted without removing the coffee grounds delivered from the first grinding cycle and a second grinding cycle is performed again. This will also cause the same issue on the following grind cycle as using a single basket on the double basket setting.
To address the above problems, the above described system 200 can be used to check the dosage amount using the tamp mechanism 11 and a check can then be made of the calculated grinding time to determine if the grind cycle is relevant to the measured tamp depth, indicating an error in the basket setting. For example, the tamp depth will indicate a double basket is only half full if a single basket setting has been selected because a single basket is approximately half the grind volume of a double basket. An adjustment to the grind will depend on different scenarios as per the below table. A range would need to be set for when this applies to each scenario.
This could be accompanied with a notification such as a Filter LED flashing or a Screen prompt to the user to advise of possible incorrect basket or filter setting selection.
Add more coffee grounds during a second grinding cycle to a portafilter with a certain amount of coffee grounds delivered from a first grinding cycle
This could also be accompanied by some form of error flashing or a screen prompt.
With regard to
Preferably, the controller 201 is configured to operate the tamp indicator 192 to illuminate in at least two states, for example a first state being a red colour and a second state being a green colour. The controller 201 is further preferably configured to operate the LED of the tamp indicator in a first state when the magnitude of the deviation is within the predetermined tolerance, and in a second state when the magnitude of the deviation is outside the predetermined tolerance.
If the deviation of the tamp depth from the predetermined ideal tamp depth exceeds a predetermined tolerance of, say, 0.5 mm the controller 201 provides information to the user interface 184 indicative of a polarity of the deviation. For example, the user interface 184 may display “overdose” or “underdose”, or correspondingly “increase grind” or “decrease grind”. Alternatively, the user interface 184 may display flavour-based feedback or adjustment settings, such as “weak”, “strong”, “perfect”. Alternatively, an indicator may indicate to the user how to adjust the grind to correct the deviation. For example, an LED may illuminate at the appropriate side of the dosage control dial or an LED on a button may flash to invite the user to press the button to add additional grind in an ‘underdose’ scenario.
For example, if the deviation of the tamp depth does not exceed the predetermined tolerance, the controller 201 may cause one or more central LEDs 193 of the user interface 184 to be illuminated, as shown in
If the deviation exceeds the predetermined tolerance by a predetermined threshold and the magnitude is positive, one or more upper LEDs 194, preferably also including the central LEDs 193 and one or more lower LEDs 195, of the indicator panel 5 to be illuminated and a warning LED 196, as shown in
Due to manufacturing tolerances, the algorithm calculations will vary slightly between different machines. As a result, factory calibration will be required to account for this.
Assumptions
To calibrate the machine, different height plastic pucks are used. The plastic pucks may, for example, be −2 and +2 pucks, indicating the height of the pucks are at −2 mm deviation and +2 mm deviation height compared to the ideal tamp height. A measurement is taken on each of the pucks respectively to determine the relationship between the measurements obtained from the linear sensor 20 and the distance from ideal. This is known as the kinematic algorithm.
x: distance from ideal
V: measurements obtained from the linear sensor 20
Methodology
Calculation
C
4
=−m·V
1
+x
1
∴x=m·V+C4
Over the course of the machine's life, coffee may build up inside the rotating tamp which reduces the rotation and height variability of the tamp. This affects the dosage algorithm as the constants calculated during factory calibration are now different.
Assumptions
To perform a calibration one measurement is needed with the single walled, single basket inserted in the portafilter to determine the relationship between the measurements obtained from the linear sensor 20 and the distance from ideal. In this case, the kinematic algorithm is as follows.
x=m·(V−V1)+x1
x: distance from ideal
V: measurements obtained from the linear sensor 20
Methodology
Calculation
x−x
1
=m·(V−V1)
x=m·(V−V1)+x1
x=m·V−m·V
1
+x
1
C
4
=−m·V
1
+x
1
3.6=−(−1)·(1.2)+(2.4))
∴x=m·V+C4
x=−1*V+3.6
x=3.6−V
Referring lastly to
In a preferred embodiment, the cover is magnetically attached/removed immediately above the portafilter holder 7 via slide-in/out motion.
A number of advantages can be realised with the above described machine and tamping mechanism.
A rotary connection between the linkage and tamp allows the tamp to be rotated away from the grind chute at a top stroke of the mechanism, which means coffee grinds can be directed into the portafilter without obstruction. The grind chute can be located directly over the portafilter as a result, which optimises distribution into the portafilter as the grinds are delivered into a centralised pile, instead of being delivered from a sideward direction which might cause an uneven distribution of coffee in the resultant tamped off puck. By swinging the tamp out of the way of the chute, the chute can be located centrally without interfering with the tamp during a tamp operation.
Since the tamp mechanism rotates the tamp at the top of the stroke, instead of linearly lifting the tamp clear of the chute, the total height of the machine can be minimised.
The tamp mechanism preferably relies on an articulated linkage formed of hinged members which provides mechanical advantage whilst again minimising total height requirements of the machine. A large stroke length is achievable through the combined linkage lengths rather than a large pinion if a rack and pinion is used. This also allows a reduced rotation angle for the lever for compact implementation of the stroke length of the tamping mechanism without needing gearing.
The mechanism provides a good ‘handle feel’ to the lever due to the torque curve not being constant for a given load so the peak load occurs only at the end of stroke. This also improves mechanical advantage near the end of stroke at the detriment of force at the beginning of the stroke length. Maximum force is only required at an end stroke of the lever.
The rotary sensor associated with the lever and/or the linear sensor detects the lever position and/or the tamp position which can be displayed on a under interface. The user interface can also provide possible next steps such that the users can be instructed/taught to make a cup of coffee.
A grind switch can be activated by lifting (rotating) the lever from its home position to start the grinder. The movements of the lever and the piston can either be manual or motorised.
The tamping force control assembly provides a bias force to assist with tamping which means a low compression distance is required making the design more compact. The pre-tensioning also means a lower spring rate spring can be used that gives a more consistent force over the compression distance.
By measuring the compression of the tamping force control assembly and/or the shaft rotation, the tamp depth can be calculated which can in turn be used to adjust the dosage. The machine can provide user feedback of the dosage through the user interface. This tamp depth can then also be used to calculate the optimum grind for the correct dosage. If underdosed, the grind can be increased. In the case of an overdose, the next grind can be reduced automatically or be displayed to the user for manual adjustment.
A manual grind mode can be implemented if the user lifts the lever for a pre-determined time. By lifting the lever, the user activates a grinder switch to start the grinder—this mode allows user to manually control the grind amount.
The portafilter can slide into the portafilter holder where it is centrally located by spring clips. It is possible also to activate a button to start the grinder. The portafilter is supported on the portafilter bayonets one of which may be supported by the button itself. The push in design allows easier insertion and reduces the clearance required under the portafilter holder for insertion if vertical fit is used.
By enclosing the tamping mechanism in a housing coffee grounds can be contained, and resultant mess drastically reduced.
The ‘handle feel’ may be improved over a rack and pinion design and the required force to tamp grinds may also be reduced over a rack and pinion with the same angle of lever rotation.
The spring preload of the tamping force control assembly is suitable for applying and controlling the tamp force over different dosage levels without the user judging the handle force.
Dosage feedback of the tamp depth or puck height is possible electronically.
Calculation of the optimal grind and “a bit more” amount is possible using electronic measurement of the puck height.
The portafilter holder design allows the portafilter to be simply slid into the portafilter holder as opposed to being lifted and rotated, as required for conventional bayonet connection. This provides an improved user experience.
1. Machine
2. Tamping unit
3. Hopper
4. Casing
5. User interface panel
6. Lever
7. Portafilter holder
8. Drip tray
9. Dial
10. Grinder
11. Tamping mechanism
12. Shaft
13. Actuator
14. Tamp
15. Tamping force control assembly
16. Piston
17. Biasing element
18. Spring
19. Connecting rod
20. Sensor
21. Grind chute
22. Flow path
23. Exit
24. Centreline
25. Face
26. End
27. Base
28. Body
29. Coupler
30. Linkage
31. End
32. Coupling
33. Housing
34. Guide Structure
35. Slots
36. First member
37. Second member
38. Notch
39.
40. Portafilter
41. Switch
42. Basket
43. Lower end
44. Limited movement connection
45. Upper end
46. Section
47. Return device
48. Tension spring
49. Fixed mount
50. Control gear
51. Rotary position sensor
52. Cog
53. Damper
54. Cog
55. Pivot
56. Slot
57. End
58. Crosspiece
59. PCB
60. Clutch
61. Hub
62. Protrusion
63. Grinder activation switch
64. Springs
65. Posts
66. Fixed structure
67. End washers
68. Carriage
69. U-shaped section
70. Extension
71. Limited movement connector
72. Rocker
73. Pivot
74. End of rocker
75. End of rocker
76. Elongate opening
77. Follower
78. Channel
79. Bracket
80. Upper end
81. Lower end
82. Pivot
83. Coffee
84. Puck
85. Rack
86. Fixed arm
87. Leg
88. Crossbeam
89. Teeth
90. Pinion
91. Slot
92. Rollers
93. Beam
94. Base
95. Lower end
96. Top
97. Vertical part
98. Curved top part
99. Remote end
100. Gear section
101. Intermediate gear
102. Rod
103. Drive shaft
104. Support
105. Second linkage
106. Tamp body
107. Side portion
108. Clearance space
109. Annular slot
110. Pin
111. Arrow
112. First disc
113. Connection members
114. Biased elements
115. Second disc
116. Connection recesses
117. Biased elements
118. Clutch disc
119. Clamp
120. Annular slots
121. Openings
122. Support Structure
123. Transverse pin
124. Support member
125. Rotating mechanism
126. Collar
127. Cylinder
128. Screw
129. Biasing element
130. Spring
131. Cam structure
132. Ramps
133. Projections
134. Side wall
135. Outer wall
136. Flange
137. Seal
138. Retaining ring
139. Rebate
140. Skirt
141. Ferrules
142. Axles
143. Axles
144. Openings
145. Circlips
146. Ferrules
147. Rubber seal
148. Inner ring
149. Base cover
150. Shoulder
151. Annular groove
152. Wiper blade
153. Track
154. Track
155. Lower portion
156. Upper portion
157. Upper portion
158. Centre line
159. Vertical line
160. Spring
161. Teeth
162. Section
163. Handle
164. Cup portion
165. Locating tabs
166. Rim
167. Access opening
168. Dock
169. Support surface
170. Support surface
171. Ramp
171
a. Support Surface
172. Clasp
173. Biased element
174. Spring clip
175. Horizontal line
176. End wall
177. Opening
178. Recess
179. Underside
180. Body
181. Inner profile
182. Tang
183. Fastener
184. Sensor
185. Sensor
186. Sensor
187. Removable cover
188. Tamp chute
200. System
201. Controller
202. Grinder module
203. Tamper module
204. User interface module
210. Centre
211. Filter cup
212. Centre axis
213. Retention member
214. Centre
215. Filter cup floor
216. Switch
217. Central axis
218. Connecting assembly
219. First inclined surface
220. Cam
221. Second inclined surface
222. Bias member
223. Stop member
224. Indicator
225. Tabs
226. Pin
Number | Date | Country | Kind |
---|---|---|---|
2020904817 | Dec 2020 | AU | national |
2021221718 | Aug 2021 | AU | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/AU21/51546 | 12/22/2021 | WO |