WO2019076871A1 - Coffee grinder with adjustment device of the distance between the blades - Google Patents

Coffee grinder with adjustment device of the distance between the blades Download PDF

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Publication number
WO2019076871A1
WO2019076871A1 PCT/EP2018/078199 EP2018078199W WO2019076871A1 WO 2019076871 A1 WO2019076871 A1 WO 2019076871A1 EP 2018078199 W EP2018078199 W EP 2018078199W WO 2019076871 A1 WO2019076871 A1 WO 2019076871A1
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WO
WIPO (PCT)
Prior art keywords
shaft
sensor
adjustment device
coffee grinder
distance
Prior art date
Application number
PCT/EP2018/078199
Other languages
French (fr)
Inventor
Ugo Albanese
Original Assignee
Conti Valerio - S.R.L.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Conti Valerio - S.R.L. filed Critical Conti Valerio - S.R.L.
Publication of WO2019076871A1 publication Critical patent/WO2019076871A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
    • A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
    • A47J42/00—Coffee mills; Spice mills
    • A47J42/12—Coffee mills; Spice mills having grinding discs
    • A47J42/18—Adjusting mechanisms

Definitions

  • the present patent application for industrial invention relates to a coffee grinder with an adjustment device of the distance between the blades.
  • traditional coffee grinders comprise a hopper in upper position, wherein the coffee beans are supplied.
  • the coffee beans falls from the hopper by gravity into a grinding chamber disposed under the hopper.
  • a grinding unit is disposed in the grinding chamber.
  • the grinding unit comprises two blades to grind the coffee beans and obtain coffee powder.
  • one blade is a rotary blade and one blade is a fixed blade.
  • the two blades are spaces out in such a way as to form an air space, wherein the coffee beans are disposed in order to be ground.
  • the coffee grinder of the prior art comprises a conveyor duct in communication with the grinding chamber and with an outlet of the ground coffee that ejects the ground coffee from the machine.
  • the conveyor duct is suitable for receiving the coffee powder.
  • a receptacle such as a filter holder, is disposed under the outlet of the conveyor duct in order to collect the coffee powder.
  • the distance between the rotary blade and the fixed blade i.e. the width of the air space between the two blades, determines the size of the ground coffee.
  • Coffee grinders are known, which comprise adjustment devices of the distance between the blades that permit an axial movement of a blade with respect to another blade.
  • the translating blade can be the rotary blade or the fixed blade in rotation.
  • the axial movement of the blade is obtained by means of mechanical means, such as for example a metal ring-threaded crown assembly, a toothed wheel-endless screw assembly, or a bar-tie rod assembly.
  • mechanical means such as for example a metal ring-threaded crown assembly, a toothed wheel-endless screw assembly, or a bar-tie rod assembly.
  • Said mechanical means permit a translation of one of the two blades along the axis of rotation of the rotary blade, in such a way to move the translating blade closer to or farther from the non-translating blade.
  • the coffee grinders with adjustment devices of the prior art are impaired by a drawback related to the fact that it is extremely difficult to set the exact distance between the blades. For example, after setting a new distance between the blades, it is practically impossible to restore the previous distance between the blades.
  • such adjustment devices are not provided with a micrometric graduated scale that permits to associate a distance between the blades to each position of the adjustment device. Consequently, it is extremely difficult for a user to set the desired size of the ground coffee.
  • Such a drawback is at least partially solved by coffee grinders comprising an adjustment device that is controlled by means of a control unit that moves the adjustment device according to the desired distance between the blades.
  • Such an adjustment device comprises actuation means that actuate the mechanical means to adjust the distance between the blades.
  • the actuation means are controlled by means of the control unit.
  • the coffee grinder provided with an adjustment device controlled by means of a control unit comprises a sensor that is connected to the control unit in such a way as to provide information on the movement of the adjustment device.
  • the actuation means comprise an electric motor and the sensor comprises an encoder that measures the rotation of the electric motor of the actuation means of the adjustment device.
  • the coffee grinders of the prior art provided with adjustment devices controlled by means of a control unit are impaired by a drawback related to the fact that the measurement made by the encoder is distorted by the natural mechanical clearance of the parts of the adjustment device. In view of the above, it is difficult to set the distance between the blades with micrometric precision.
  • said coffee grinders of the prior art provided with adjustment devices controlled by means of a control unit do not measure the real distance between the blades, but only estimate said distance according to the rotation of the electric motor of the actuation means of the adjustment device.
  • US7874505 discloses a coffee grinder with a translating shaft connected to a blade.
  • An adjustment device is connected to the translating shaft in order to make it translate in such a way as to adjust the distance between the two blades.
  • the adjustment device comprises a stepping motor that translates a pin coupled at the lower end of the translating shaft.
  • a position sensor integrated in the stepping motor detects the relative position of the pin with respect to the fixed body of the stepping motor.
  • the position of the pin can be determined by an encoder that counts the number of revolutions of the stepping motor.
  • US7874505 is impaired by a drawback related to the fact that the sensor integrated in the stepping motor does not consider the mechanical clearance that exists in the spherical coupling between the pin of the stepping motor and the translating shaft. Consequently, the measurement made by said sensor integrated in the motor, and the measurement made by an encoder of the motor is not precise.
  • the purpose of the present invention is to overcome the drawbacks of the prior art by devising a coffee grinder provided with an adjustment device that permits to move the translating blade with micrometric precision.
  • Another purpose is to disclose a coffee grinder provided with a sensor that is capable of detecting the actual distance between the blades.
  • An additional purpose is to disclose a coffee grinder with an adjustment device, which is reliable and simple to use.
  • the coffee grinder of the invention is defined by the independent claim
  • the sensor has a sensitive portion and a reference portion disposed outside of the actuator of the adjustment device and integral with the frame and the shaft of the coffee grinder.
  • Fig. 1 is a sectional view of a coffee grinder according to the invention, taken along a vertical plane.
  • Fig. 2 is a sectional view of an adjustment device applied to the blades of the coffee grinder of Fig. 1 , taken along a vertical plane;
  • Fig. 3 is a top view of the adjustment device of Fig. 2.
  • a coffee grinder according to the invention is disclosed, which is generally indicated with numeral (100).
  • the coffee grinder (100) is of instantaneous type.
  • the coffee grinder (100) comprises a hopper (1 ) and a frame (5) disposed under the hopper (1 ).
  • the coffee grinder (100) comprises a grinding unit (3) disposed in the frame (5) and in communication with the hopper (1 ).
  • the coffee beans that are contained in the hopper (1 ) descend towards the grinding unit (3) by gravity or are moved by means of a conveyor (10) disposed in a dispensing nozzle (1 a) of the hopper (1 ), with a vertical axis (Z).
  • the coffee grinder (100) comprises a conveyor cone (1 1 ) obtained in the frame (5) under the hopper (1 ).
  • the conveyor cone (1 1 ) is suitable for receiving the coffee beans from the hopper (1 ).
  • the conveyor cone (1 1 ) has an outlet in communication with an inlet (35) of the grinding unit (3).
  • the grinding unit (3) comprises two blades (30, 31 ): a first blade (30) and a second blade (31 ).
  • the blades (30, 31 ) are planar blades and are spaced out in such a way as to form an air space (32), through which the ground coffee powder is ejected.
  • the blades (30, 31 ) may be conical.
  • Actuation means (4) are connected to at least one of the two blades in order to rotate one blade or both blades. In the figures, the actuation means (4) are connected to the first blade (30) to rotate the first blade (30).
  • the first blade (30) rotates around an axis of rotation (Y).
  • the axis of rotation (Y) of the first blade (30) is advantageously inclined with respect to the vertical axis (Z) of the outlet (1 a) of the hopper (1 ) by an angle of approximately 40° - 60°.
  • the axis of rotation (Y) of the first blade (30) can be horizontal or vertical.
  • the coffee grinder comprises a shaft (42) wherein the rotary blade is keyed, or two shafts wherein the two rotary blades are keyed, in case of two rotary blades.
  • the actuation means (4) rotate the shaft (42).
  • the shaft (42) is revolvingly mounted with respect to the frame (5).
  • the actuation means (4) comprise an electric motor (40) and a transmission (43) that actuate the shaft (42).
  • the electric motor (40) is supported by the frame (5) of the coffee grinder
  • the electric motor (40) has a drive shaft (41 ) advantageously provided with an axis that is parallel to the axis of rotation (Y) of the first blade (30).
  • the shaft (42) of the coffee grinder has an axis that is parallel to the axis of the drive shaft (41 ) and coincides with the axis of rotation (Y) of the first blade (30).
  • the transmission means (43) transmit the motion from the drive shaft (41 ) to the shaft (42) of the coffee grinder, in such a way as to rotate the first blade (30).
  • the transmission means (43) comprise a transmission belt and two pulleys (44) respectively disposed on the shaft (41 ) of the motor (41 ) and on the shaft (42) of the rotary blade (30), in such a way to return the belt.
  • the coffee grinder comprises a funnel (6) obtained in the frame (5) and in communication with the conveyor cone (1 1 ) and with the exterior.
  • the funnel (6) houses the blades (30, 31 ), in such a way that the coffee powder that is ejected radially from the air space (32) between the blades (30, 31 ) is already contained in the funnel (6).
  • the funnel (6) permits the coffee powder to be conveyed towards the exterior.
  • the funnel (6) is basically vertical and comprises an outlet (60) in lower position in communication with the exterior.
  • the coffee beans that are ejected from the hopper (1 ) pass through the blades (30, 31 ), which grind the coffee.
  • the ground coffee falls directly inside the funnel (6) where the blades (30, 31 ) are disposed, and is conveyed towards the exterior.
  • the coffee grinder (100) comprises an adjustment device (7) to adjust the distance between the first blade (30) and the second blade (31 ).
  • the adjustment device (7) is connected to the shaft (42) wherein one of the two blades is keyed.
  • Such a shaft (42) can translate in order to cause the translation of the blade keyed on said shaft.
  • the shaft (42) of the coffee grinder is connected both to the adjustment device (7) and to the actuation means (4).
  • the rotary blade can translate with respect to the fixed blade.
  • the adjustment device (7) is disposed inside a housing of the frame (5).
  • the adjustment device (7) can comprise mechanical means, such as for example a lever mechanism or a screw-female screw assembly, suitable for causing the translation of the shaft (42).
  • the adjustment device (7) comprises a metal ring (72) with an opening for the shaft (42).
  • the adjustment device (7) comprises a thrust bearing (75) connected to the metal ring (72) and to the shaft (42), in such a way that the shaft (42) can rotate with respect to the metal ring (72), while being constrained to the metal ring (72) in translation.
  • the metal ring (72) comprises an external thread that cooperates with an internal thread of a sleeve (74) fixed to the frame (5) of the coffee grinder (100), in such a way that the metal ring (72) can be screwed in the sleeve (74).
  • the screwing of the metal ring (72) with respect to the sleeve (74) causes a translation of the metal ring (72) along the axis of rotation (Y). Consequently, also the shaft (42) and the first blade (30) translate along the axis of rotation (Y). Such a translation moves the first blade (30) closer to or farther from the second blade (31 ), in such a way to reduce/increase the width of the air space between the two blades (30, 31 ). The higher the width of the air space between the blades (30, 31 ), the larger the size of the coffee powder will be.
  • the sleeve (74) comprise a chamber crossed by the shaft (42).
  • a first bearing (76a) is slidingly mounted inside said chamber of the sleeve.
  • the first bearing (76a) is connected to the shaft (42), in such a way as to support the shaft (42) during the translation of said shaft (42) in axial direction.
  • the adjustment device (7) comprises an elastic element (77) that is housed in the chamber of sleeve (74).
  • the elastic element (77) is positioned in such a way to push the shaft (42) away from the blades (30, 31 ).
  • the elastic element (77) guarantees that the mechanical clearance caused by the thrust bearing (75) or by the metal ring/sleeve coupling does not affect the correct axial position of the shaft (42).
  • the elastic element (77) is a helical spring disposed around the shaft (42).
  • Said helical shaft has a first end in contact with the sleeve (74) and a second end in contact with the first bearing (76a).
  • a second bearing (76b) is slidingly mounted in the housing of the frame (5) and is connected to the shaft (42) to support said shaft (42) during the translation.
  • the adjustment device (7) comprises an actuator (70) connected to the metal ring (72) in order to rotate the metal ring (72).
  • the actuator (70) can comprise any type of actuation means, such as for example an electric motor, a stepping motor, which is directly connected to the metal ring in direct drive mode or is connected to the metal ring by means of any type of drive means.
  • actuation means such as for example an electric motor, a stepping motor, which is directly connected to the metal ring in direct drive mode or is connected to the metal ring by means of any type of drive means.
  • the actuator (70) of the adjustment device (7) comprises an electrically-operated gear motor (70a) with a shaft, connected to transmission means (71 ) in order to transmit the motion from the shaft of the electrically-operated gear motor to the metal ring (72).
  • the transmission means (71 ) comprise an endless screw (71 a) connected to the shaft of the electrically-operated gear motor and a toothed wheel (71 b) joined to the metal ring (72) and cooperating with the endless screw (71 a) in order to rotate the metal ring (72).
  • the electrically-operated gear motor (70a) of the actuator of the adjustment device rotates the endless screw (71 a).
  • the endless screw (71 a) engages the teeth of the toothed wheel (71 b) and rotates the metal ring (72).
  • the metal ring (72) is screwed to/unscrewed from the sleeve (74).
  • the coffee grinder (100) comprises a distance sensor (8) suitable for measuring the actual travel made by the assembly that comprises the shaft (42) and the first blade (30).
  • the sensor (8) is disposed out of the actuator (70).
  • the sensor (8) comprises a sensitive portion (80) and a reference portion (81 ).
  • One of the two portions of the sensor (8) is integral with the frame (5) and the other portion of the sensor (8) is integral with the shaft (42) of the coffee grinder, in such a way that the sensor (8) measures the distance between the frame (5) and the shaft (42) of the coffee grinder in a direction that is parallel with respect to the axis of the shaft (42), i.e. with respect to the axis of translation of the blade (30) to be translated.
  • the measurement detected by the sensor (8) is not affected by the clearance that is created between the actuator and the shaft (42) of the coffee grinder.
  • the maximum axial travel of the shaft (42) depends on the resolution of the sensor (8) and is approximately 3 mm.
  • the sensor (8) can be any type of distance sensor, such as for example an inductive sensor, a laser sensor or an ultrasound sensor.
  • the sensor (8) is an inductive sensor.
  • the sensitive portion (80) is fixed to the frame (5) in the proximity of the metal ring (72) and is advantageously aligned with the axis of translation.
  • the reference portion (81 ) comprises a metal surface (8a), such as for example a metal plate, which is disposed on the shaft (42) or on the metal ring (72) and is aligned with the sensitive portion (80), in such a way that the sensitive portion (80) of the sensor (8) can detect the distance between the sensitive portion (80) and the reference portion (81 ).
  • the shaft (42) of the coffee grinder comprises a first end wherein the first blade (30) is fixed, and a second end that projects from the metal ring (72).
  • the metal surface (8a) is disposed on the second end of the shaft (42).
  • the metal surface (8a) can be disposed on the metal ring (72) or the metal surface (8a) can be fixed to the frame (5) and the sensitive portion
  • the (80) of the sensor (8) can be disposed on the metal ring (72) or on the second end of the shaft (42), in such a way as to be aligned with the reference portion
  • the sensor (8) which is disposed in such a way as to measure the distance between the sensitive portion (80) and the reference portion (81 ), which is fixed at the second end of the shaft (42) of the coffee grinder in a parallel direction with respect to the axis of translation of the shaft (42), it is possible to measure the actual distance between the second end of the shaft (42) of the coffee grinder and the sensitive portion (80) of the sensor (8), which is in proportion to the distance between the two blades (30, 31 ).
  • the coffee grinder (100) advantageously comprises a user interface, such for example a keyboard or a touch screen, used to enter the value of the desired distance between the blades.
  • the coffee grinder (100) advantageously comprises a display suitable for displaying the value of the desired distance between the blades (30, 31 ).
  • the coffee grinder (100) comprises a control unit (which is not shown in the figures) to control the translation of the assembly that comprises the shaft (42) and the first blade (30).
  • the control unit is electrically connected to the sensitive portion (80) of the sensor (8), to the user interface and to the actuator (70) of the adjustment device (7), in such a way to receive the desired distance value from the user interface, send an activation command to the actuator (70) of the adjustment device (7) to change the distance between the two blades (30, 31 ), receive real time information from the sensor (8) on the distance between the sensitive portion (80) and the reference portion (81 ) of the sensor (8), and send an off command to the actuator (70) of the adjustment device (7) when the distance measured by the sensor (8) coincides with the desired distance between the blades (30, 31 ).
  • the control unit sends an actuation command to the electrically- operated gear motor (70a) of the actuator (70) of the adjustment device (7), in such a way as to rotate the metal ring (72).
  • the metal ring (72) is screwed to or unscrewed from the sleeve (74) and translates with respect to the sleeve (74), causing a translation of the shaft (42) of the coffee grinder and of the first blade (30) along the axis of translation of the shaft (42) of the coffee grinder.
  • the sensor (8) sends real time information to the control unit on the actual measurement of the distance between the sensitive portion (80) and the reference portion (81 ) of the sensor (8), i.e. on the actual distance traveled by the shaft (42) of the coffee grinder.
  • the measurement detected by said sensor (8) is not affected by the inaccuracy caused by the clearance between the actuator (70) and the shaft (42) of the coffee grinder.
  • the control unit When the distance detected by the sensor (8) coincides with the preset distance value, the control unit sends an off command to the electric motor of the actuator (70) of the adjustment device (7).
  • the sensor (8) and of the adjustment device (7) permits a higher repeatability of the adjustment operation of the distance between the blades (30, 31 ) and the measurements of the travel made by the shaft (42) of the coffee grinder are not affected by the mechanical clearance of the parts of the adjustment device (7).
  • the sensor (8) does not count the revolutions of the electric motor in order to obtain the distance between the blades, but directly measures the distance between the two blades (30, 31 ) according to the distance between the sensitive portion (80) and the reference portion (81 ) of the sensor (8).
  • the transmission means (43) of the actuation means (4) may be omitted.
  • the shaft (42) can be the drive shaft of the electric motor (40). Therefore, the shaft of the electric motor is translated by the adjustment device (7).
  • the sensitive portion (81 ) can be disposed at the end of the shaft of the electric motor (40).
  • the coffee grinder (100) can comprise a grinding chamber, which is obtained in the frame in communication with the hopper and the funnel (6).
  • the blades (30, 31 ) are disposed in the grinding chamber.
  • the first blade (30) can be rotating and fixed in translation and the second blade (31 ) can be translating and fixed in rotation.
  • the first blade (30) is keyed on the shaft moved by the actuation means in order to rotate the first blade
  • the second blade (31 ) is keyed on the shaft connected to the adjustment device (7) in such a way that the adjustment device translates the second blade (31 ).
  • the first blade (30) can be a translating blade and fixed in rotation and the second blade (31 ) can be rotating and fixed in translation.
  • the first blade is keyed on the shaft connected to the adjustment device, and the second blade is keyed on the shaft connected to the actuation means.
  • the first blade (30) can be fixed in rotation and in translation and the second blade (31 ) can be rotating and translating.
  • the second blade is keyed on a shaft connected both to the actuation means and to the adjustment device.

Abstract

Coffee grinder (100) comprising: a frame (5); a grinding unit (3) comprising a first blade (30) and a second blade (31), actuation means (4) for rotating one blade, a translating shaft (42) whereon said first blade (30) is keyed, an adjustment device (7) comprising an actuator (70) for translating the shaft (42), a sensor (8) for measuring the distance between the two blades (30, 31); the sensor (8) comprises a sensitive portion (80) and a reference portion (81); a portion of the sensor (8) is fixed and integral with the frame (5) of the coffee grinder and the other portion of the sensor (8) is integral in translation with the shaft (42) of the coffee grinder.

Description

COFFEE GRINDER WITH ADJUSTMENT DEVICE OF THE DISTANCE
BETWEEN THE BLADES
DESCRIPTION
The present patent application for industrial invention relates to a coffee grinder with an adjustment device of the distance between the blades.
As it is known, traditional coffee grinders comprise a hopper in upper position, wherein the coffee beans are supplied. The coffee beans falls from the hopper by gravity into a grinding chamber disposed under the hopper.
A grinding unit is disposed in the grinding chamber. The grinding unit comprises two blades to grind the coffee beans and obtain coffee powder. Generally speaking, one blade is a rotary blade and one blade is a fixed blade. The two blades are spaces out in such a way as to form an air space, wherein the coffee beans are disposed in order to be ground.
The coffee grinder of the prior art comprises a conveyor duct in communication with the grinding chamber and with an outlet of the ground coffee that ejects the ground coffee from the machine. The conveyor duct is suitable for receiving the coffee powder. A receptacle, such as a filter holder, is disposed under the outlet of the conveyor duct in order to collect the coffee powder.
The distance between the rotary blade and the fixed blade, i.e. the width of the air space between the two blades, determines the size of the ground coffee.
Coffee grinders are known, which comprise adjustment devices of the distance between the blades that permit an axial movement of a blade with respect to another blade.
It must be noted that the translating blade can be the rotary blade or the fixed blade in rotation.
The axial movement of the blade is obtained by means of mechanical means, such as for example a metal ring-threaded crown assembly, a toothed wheel-endless screw assembly, or a bar-tie rod assembly. Said mechanical means permit a translation of one of the two blades along the axis of rotation of the rotary blade, in such a way to move the translating blade closer to or farther from the non-translating blade.
The coffee grinders with adjustment devices of the prior art are impaired by a drawback related to the fact that it is extremely difficult to set the exact distance between the blades. For example, after setting a new distance between the blades, it is practically impossible to restore the previous distance between the blades. In fact, such adjustment devices are not provided with a micrometric graduated scale that permits to associate a distance between the blades to each position of the adjustment device. Consequently, it is extremely difficult for a user to set the desired size of the ground coffee.
Such a drawback is at least partially solved by coffee grinders comprising an adjustment device that is controlled by means of a control unit that moves the adjustment device according to the desired distance between the blades. Such an adjustment device comprises actuation means that actuate the mechanical means to adjust the distance between the blades. The actuation means are controlled by means of the control unit.
The coffee grinder provided with an adjustment device controlled by means of a control unit comprises a sensor that is connected to the control unit in such a way as to provide information on the movement of the adjustment device. Generally speaking, the actuation means comprise an electric motor and the sensor comprises an encoder that measures the rotation of the electric motor of the actuation means of the adjustment device.
The coffee grinders of the prior art provided with adjustment devices controlled by means of a control unit are impaired by a drawback related to the fact that the measurement made by the encoder is distorted by the natural mechanical clearance of the parts of the adjustment device. In view of the above, it is difficult to set the distance between the blades with micrometric precision.
Moreover, said coffee grinders of the prior art provided with adjustment devices controlled by means of a control unit do not measure the real distance between the blades, but only estimate said distance according to the rotation of the electric motor of the actuation means of the adjustment device.
US7874505 discloses a coffee grinder with a translating shaft connected to a blade. An adjustment device is connected to the translating shaft in order to make it translate in such a way as to adjust the distance between the two blades. The adjustment device comprises a stepping motor that translates a pin coupled at the lower end of the translating shaft. A position sensor integrated in the stepping motor detects the relative position of the pin with respect to the fixed body of the stepping motor. Alternatively or additionally to said position sensor, the position of the pin can be determined by an encoder that counts the number of revolutions of the stepping motor.
US7874505 is impaired by a drawback related to the fact that the sensor integrated in the stepping motor does not consider the mechanical clearance that exists in the spherical coupling between the pin of the stepping motor and the translating shaft. Consequently, the measurement made by said sensor integrated in the motor, and the measurement made by an encoder of the motor is not precise.
The purpose of the present invention is to overcome the drawbacks of the prior art by devising a coffee grinder provided with an adjustment device that permits to move the translating blade with micrometric precision.
Another purpose is to disclose a coffee grinder provided with a sensor that is capable of detecting the actual distance between the blades.
An additional purpose is to disclose a coffee grinder with an adjustment device, which is reliable and simple to use.
These purposes are achieved according to the invention with the characteristics of the appended independent claim 1 .
Advantageous embodiments appear from the dependent claims.
The coffee grinder of the invention is defined by the independent claim
1 .
The advantages of the coffee grinder according to the invention are evident, wherein the provision of a sensor disposed outside the actuator of the adjustment device makes it possible to measure the distance between the blades without being affected by the inaccuracies caused by the clearance created when coupling the actuator with the shaft of the coffee grinder.
The sensor has a sensitive portion and a reference portion disposed outside of the actuator of the adjustment device and integral with the frame and the shaft of the coffee grinder.
For the sake of clarity, the description of the coffee grinder according to the invention continues with reference to the appended drawings, which have a merely illustrative, not limiting value, wherein:
Fig. 1 is a sectional view of a coffee grinder according to the invention, taken along a vertical plane.
Fig. 2 is a sectional view of an adjustment device applied to the blades of the coffee grinder of Fig. 1 , taken along a vertical plane;
Fig. 3 is a top view of the adjustment device of Fig. 2.
With reference to Fig. 1 , a coffee grinder according to the invention is disclosed, which is generally indicated with numeral (100).
The coffee grinder (100) is of instantaneous type. The coffee grinder (100) comprises a hopper (1 ) and a frame (5) disposed under the hopper (1 ). The coffee grinder (100) comprises a grinding unit (3) disposed in the frame (5) and in communication with the hopper (1 ).
The coffee beans that are contained in the hopper (1 ) descend towards the grinding unit (3) by gravity or are moved by means of a conveyor (10) disposed in a dispensing nozzle (1 a) of the hopper (1 ), with a vertical axis (Z).
The coffee grinder (100) comprises a conveyor cone (1 1 ) obtained in the frame (5) under the hopper (1 ).The conveyor cone (1 1 ) is suitable for receiving the coffee beans from the hopper (1 ). The conveyor cone (1 1 ) has an outlet in communication with an inlet (35) of the grinding unit (3).
The grinding unit (3) comprises two blades (30, 31 ): a first blade (30) and a second blade (31 ).
The blades (30, 31 ) are planar blades and are spaced out in such a way as to form an air space (32), through which the ground coffee powder is ejected. Alternatively, the blades (30, 31 ) may be conical. Actuation means (4) are connected to at least one of the two blades in order to rotate one blade or both blades. In the figures, the actuation means (4) are connected to the first blade (30) to rotate the first blade (30).
The first blade (30) rotates around an axis of rotation (Y). The axis of rotation (Y) of the first blade (30) is advantageously inclined with respect to the vertical axis (Z) of the outlet (1 a) of the hopper (1 ) by an angle of approximately 40° - 60°. Alternatively, the axis of rotation (Y) of the first blade (30) can be horizontal or vertical.
The coffee grinder comprises a shaft (42) wherein the rotary blade is keyed, or two shafts wherein the two rotary blades are keyed, in case of two rotary blades. The actuation means (4) rotate the shaft (42).
The shaft (42) is revolvingly mounted with respect to the frame (5). The actuation means (4) comprise an electric motor (40) and a transmission (43) that actuate the shaft (42).
The electric motor (40) is supported by the frame (5) of the coffee grinder
(100). The electric motor (40) has a drive shaft (41 ) advantageously provided with an axis that is parallel to the axis of rotation (Y) of the first blade (30).
The shaft (42) of the coffee grinder has an axis that is parallel to the axis of the drive shaft (41 ) and coincides with the axis of rotation (Y) of the first blade (30).
The transmission means (43) transmit the motion from the drive shaft (41 ) to the shaft (42) of the coffee grinder, in such a way as to rotate the first blade (30).
Advantageously, the transmission means (43) comprise a transmission belt and two pulleys (44) respectively disposed on the shaft (41 ) of the motor (41 ) and on the shaft (42) of the rotary blade (30), in such a way to return the belt.
The coffee grinder comprises a funnel (6) obtained in the frame (5) and in communication with the conveyor cone (1 1 ) and with the exterior. The funnel (6) houses the blades (30, 31 ), in such a way that the coffee powder that is ejected radially from the air space (32) between the blades (30, 31 ) is already contained in the funnel (6). The funnel (6) permits the coffee powder to be conveyed towards the exterior.
The funnel (6) is basically vertical and comprises an outlet (60) in lower position in communication with the exterior.
The coffee beans that are ejected from the hopper (1 ) pass through the blades (30, 31 ), which grind the coffee. The ground coffee falls directly inside the funnel (6) where the blades (30, 31 ) are disposed, and is conveyed towards the exterior.
The coffee grinder (100) comprises an adjustment device (7) to adjust the distance between the first blade (30) and the second blade (31 ). The adjustment device (7) is connected to the shaft (42) wherein one of the two blades is keyed. Such a shaft (42) can translate in order to cause the translation of the blade keyed on said shaft.
The shaft (42) of the coffee grinder is connected both to the adjustment device (7) and to the actuation means (4). In view of the above, the rotary blade can translate with respect to the fixed blade.
The adjustment device (7) is disposed inside a housing of the frame (5). The adjustment device (7) can comprise mechanical means, such as for example a lever mechanism or a screw-female screw assembly, suitable for causing the translation of the shaft (42).
In the embodiment of Figs. 2 and 3, the adjustment device (7) comprises a metal ring (72) with an opening for the shaft (42). The adjustment device (7) comprises a thrust bearing (75) connected to the metal ring (72) and to the shaft (42), in such a way that the shaft (42) can rotate with respect to the metal ring (72), while being constrained to the metal ring (72) in translation.
The metal ring (72) comprises an external thread that cooperates with an internal thread of a sleeve (74) fixed to the frame (5) of the coffee grinder (100), in such a way that the metal ring (72) can be screwed in the sleeve (74).
The screwing of the metal ring (72) with respect to the sleeve (74) causes a translation of the metal ring (72) along the axis of rotation (Y). Consequently, also the shaft (42) and the first blade (30) translate along the axis of rotation (Y). Such a translation moves the first blade (30) closer to or farther from the second blade (31 ), in such a way to reduce/increase the width of the air space between the two blades (30, 31 ). The higher the width of the air space between the blades (30, 31 ), the larger the size of the coffee powder will be.
Advantageously, the sleeve (74) comprise a chamber crossed by the shaft (42). A first bearing (76a) is slidingly mounted inside said chamber of the sleeve. The first bearing (76a) is connected to the shaft (42), in such a way as to support the shaft (42) during the translation of said shaft (42) in axial direction.
The adjustment device (7) comprises an elastic element (77) that is housed in the chamber of sleeve (74). The elastic element (77) is positioned in such a way to push the shaft (42) away from the blades (30, 31 ). In view of the above, the elastic element (77) guarantees that the mechanical clearance caused by the thrust bearing (75) or by the metal ring/sleeve coupling does not affect the correct axial position of the shaft (42). More precisely, the elastic element (77) is a helical spring disposed around the shaft (42). Said helical shaft has a first end in contact with the sleeve (74) and a second end in contact with the first bearing (76a).
Advantageously, a second bearing (76b) is slidingly mounted in the housing of the frame (5) and is connected to the shaft (42) to support said shaft (42) during the translation.
Because of the metal ring (72) that is screwed in the sleeve (4), very small movements, namely of hundredths of millimeter, can be made by the first blade (39) with very high accuracy.
The adjustment device (7) comprises an actuator (70) connected to the metal ring (72) in order to rotate the metal ring (72).
The actuator (70) can comprise any type of actuation means, such as for example an electric motor, a stepping motor, which is directly connected to the metal ring in direct drive mode or is connected to the metal ring by means of any type of drive means.
For example, as shown in Figs. 2 and 3, the actuator (70) of the adjustment device (7) comprises an electrically-operated gear motor (70a) with a shaft, connected to transmission means (71 ) in order to transmit the motion from the shaft of the electrically-operated gear motor to the metal ring (72). The transmission means (71 ) comprise an endless screw (71 a) connected to the shaft of the electrically-operated gear motor and a toothed wheel (71 b) joined to the metal ring (72) and cooperating with the endless screw (71 a) in order to rotate the metal ring (72).
The electrically-operated gear motor (70a) of the actuator of the adjustment device rotates the endless screw (71 a). By rotating, the endless screw (71 a) engages the teeth of the toothed wheel (71 b) and rotates the metal ring (72). In this way, the metal ring (72) is screwed to/unscrewed from the sleeve (74).
The coffee grinder (100) comprises a distance sensor (8) suitable for measuring the actual travel made by the assembly that comprises the shaft (42) and the first blade (30). The sensor (8) is disposed out of the actuator (70). The sensor (8) comprises a sensitive portion (80) and a reference portion (81 ). One of the two portions of the sensor (8) is integral with the frame (5) and the other portion of the sensor (8) is integral with the shaft (42) of the coffee grinder, in such a way that the sensor (8) measures the distance between the frame (5) and the shaft (42) of the coffee grinder in a direction that is parallel with respect to the axis of the shaft (42), i.e. with respect to the axis of translation of the blade (30) to be translated. In view of the above, the measurement detected by the sensor (8) is not affected by the clearance that is created between the actuator and the shaft (42) of the coffee grinder.
It must be noted that the maximum axial travel of the shaft (42) depends on the resolution of the sensor (8) and is approximately 3 mm.
The sensor (8) can be any type of distance sensor, such as for example an inductive sensor, a laser sensor or an ultrasound sensor.
As shown in Figs. 2 and 3, the sensor (8) is an inductive sensor. The sensitive portion (80) is fixed to the frame (5) in the proximity of the metal ring (72) and is advantageously aligned with the axis of translation. The reference portion (81 ) comprises a metal surface (8a), such as for example a metal plate, which is disposed on the shaft (42) or on the metal ring (72) and is aligned with the sensitive portion (80), in such a way that the sensitive portion (80) of the sensor (8) can detect the distance between the sensitive portion (80) and the reference portion (81 ).
The shaft (42) of the coffee grinder comprises a first end wherein the first blade (30) is fixed, and a second end that projects from the metal ring (72). The metal surface (8a) is disposed on the second end of the shaft (42). Alternatively, the metal surface (8a) can be disposed on the metal ring (72) or the metal surface (8a) can be fixed to the frame (5) and the sensitive portion
(80) of the sensor (8) can be disposed on the metal ring (72) or on the second end of the shaft (42), in such a way as to be aligned with the reference portion
(81 ) of the sensor (8).
Because of the provision of the sensor (8), which is disposed in such a way as to measure the distance between the sensitive portion (80) and the reference portion (81 ), which is fixed at the second end of the shaft (42) of the coffee grinder in a parallel direction with respect to the axis of translation of the shaft (42), it is possible to measure the actual distance between the second end of the shaft (42) of the coffee grinder and the sensitive portion (80) of the sensor (8), which is in proportion to the distance between the two blades (30, 31 ).
The coffee grinder (100) advantageously comprises a user interface, such for example a keyboard or a touch screen, used to enter the value of the desired distance between the blades. The coffee grinder (100) advantageously comprises a display suitable for displaying the value of the desired distance between the blades (30, 31 ).
The coffee grinder (100) comprises a control unit (which is not shown in the figures) to control the translation of the assembly that comprises the shaft (42) and the first blade (30). The control unit is electrically connected to the sensitive portion (80) of the sensor (8), to the user interface and to the actuator (70) of the adjustment device (7), in such a way to receive the desired distance value from the user interface, send an activation command to the actuator (70) of the adjustment device (7) to change the distance between the two blades (30, 31 ), receive real time information from the sensor (8) on the distance between the sensitive portion (80) and the reference portion (81 ) of the sensor (8), and send an off command to the actuator (70) of the adjustment device (7) when the distance measured by the sensor (8) coincides with the desired distance between the blades (30, 31 ).
When a user sends a command to change the distance between the blades (30, 31 ), the control unit sends an actuation command to the electrically- operated gear motor (70a) of the actuator (70) of the adjustment device (7), in such a way as to rotate the metal ring (72). By rotating, the metal ring (72) is screwed to or unscrewed from the sleeve (74) and translates with respect to the sleeve (74), causing a translation of the shaft (42) of the coffee grinder and of the first blade (30) along the axis of translation of the shaft (42) of the coffee grinder. During such a movement, the sensor (8) sends real time information to the control unit on the actual measurement of the distance between the sensitive portion (80) and the reference portion (81 ) of the sensor (8), i.e. on the actual distance traveled by the shaft (42) of the coffee grinder.
Because of the fact that the sensor (8) is disposed with a portion that is integral to the fixed frame, and another portion that is integral with the translating shaft, the measurement detected by said sensor (8) is not affected by the inaccuracy caused by the clearance between the actuator (70) and the shaft (42) of the coffee grinder.
When the distance detected by the sensor (8) coincides with the preset distance value, the control unit sends an off command to the electric motor of the actuator (70) of the adjustment device (7).
The provision of the sensor (8) and of the adjustment device (7) permits a higher repeatability of the adjustment operation of the distance between the blades (30, 31 ) and the measurements of the travel made by the shaft (42) of the coffee grinder are not affected by the mechanical clearance of the parts of the adjustment device (7). In fact, unlike the encoders used in the coffee grinders of the prior art, the sensor (8) does not count the revolutions of the electric motor in order to obtain the distance between the blades, but directly measures the distance between the two blades (30, 31 ) according to the distance between the sensitive portion (80) and the reference portion (81 ) of the sensor (8).
Although it is not shown in the figures, the transmission means (43) of the actuation means (4) may be omitted. In such a case, the shaft (42) can be the drive shaft of the electric motor (40). Therefore, the shaft of the electric motor is translated by the adjustment device (7). Moreover, in such a case, the sensitive portion (81 ) can be disposed at the end of the shaft of the electric motor (40).
Although it is not shown in the figures, the coffee grinder (100) can comprise a grinding chamber, which is obtained in the frame in communication with the hopper and the funnel (6). In such a case, the blades (30, 31 ) are disposed in the grinding chamber.
Although it is not shown in the figures, the first blade (30) can be rotating and fixed in translation and the second blade (31 ) can be translating and fixed in rotation. In such a case, the first blade (30) is keyed on the shaft moved by the actuation means in order to rotate the first blade, whereas the second blade (31 ) is keyed on the shaft connected to the adjustment device (7) in such a way that the adjustment device translates the second blade (31 ).
Alternatively, the first blade (30) can be a translating blade and fixed in rotation and the second blade (31 ) can be rotating and fixed in translation. In such a case, the first blade is keyed on the shaft connected to the adjustment device, and the second blade is keyed on the shaft connected to the actuation means.
Alternatively, the first blade (30) can be fixed in rotation and in translation and the second blade (31 ) can be rotating and translating. In such a case, the second blade is keyed on a shaft connected both to the actuation means and to the adjustment device.

Claims

1 ) Coffee grinder (100) comprising:
- a frame (5);
- a grinding unit (3) disposed in the frame (5); said grinding unit (3) comprising a first blade (30) and a second blade (31 ) disposed in such a way as to form an air space (32) where the coffee beans are ground;
- actuation means (4) suitable for rotating at least one of the two blades;
- a shaft (42) whereon said first blade (30) is keyed; said shaft (42) being mounted in such a way as to translate axially;
- an adjustment device (7) comprising an actuator (70), said adjustment device (7) being connected to said shaft (42) to translate said shaft (42), in such a way as to adjust the distance between the first blade (30) and the second blade (31 );
- a sensor (8) suitable for measuring the distance between the two blades (30, 31 ); said sensor (8) comprising a sensitive portion (80) and a reference portion (81 ), in such a way as to measure the distance between the sensitive portion and the reference portion;
characterized in that
said sensor (8) is disposed outside the actuator (70) of the adjustment device (7) and
one of the two portions of the sensor (8) is fixed and integral with the frame (5) of the coffee grinder and the other portion of the sensor (8) is integral in translation with the shaft (42) of the coffee grinder, in such a way that said sensor (8) measures the distance between the frame (5) and the shaft (42) of the coffee grinder in a direction that is parallel with respect to the axis of translation of the shaft of the coffee grinder.
2) The coffee grinder (100) of claim 1 , wherein the sensor (8) is an inductive sensor.
3) The coffee grinder (100) of claim 2, wherein said sensitive portion (80) of the sensor (8) is fixed to the frame (5); said reference portion (81 ) comprising a metal surface (8a) disposed at one end of the shaft (42) of the coffee grinder; said metal surface (8a) being aligned with said sensitive portion (80) of the sensor (8).
4) The coffee grinder (100) of claim 2, wherein said sensitive portion (80) of the sensor (8) is fixed at one end of the shaft (42) of the coffee grinder; said reference portion (81 ) comprising a metal surface (8a) fixed to the frame (5); said metal surface (8a) being aligned with said sensitive portion (80) of the sensor (8).
5) The frame (100) of any one of the preceding claims, wherein the adjustment device (7) comprises:
- a metal ring (72) connected to the shaft (42) of the adjustment device; said metal ring (72) being provided with an external thread;
- a thrust bearing (75) connected to the metal ring (72) and to the shaft (42) of the adjustment device, in such a way that the shaft (42) of the adjustment device can rotate with respect to the metal ring (72), while being constrained to the metal ring (72) in translation;
- a sleeve (74) fixed to the frame (5) and comprising an internal thread that cooperates with an external thread of the metal ring (72), in such a way that the metal ring (72) can be screwed/unscrewed with respect to the sleeve (74).
6) The coffee grinder (100) of claim 5, wherein said sleeve (74) comprises a chamber crossed by the shaft (42) of the adjustment device; said adjustment device (7) comprising an elastic element (77) housed inside the chamber of the sleeve (74); said elastic element (77) being positioned in such a way to push the shaft (42) of the adjustment device in a direction away from the blades.
7) The coffee grinder (100) of claim 6, wherein said actuator (70) is connected to the metal ring (72) to rotate the metal ring (72).
8) The coffee grinder (100) of claim 7, wherein said actuator (70) of the adjustment device (7) comprises:
- an electrically-operated gear motor (70a) provided with a shaft; - transmission means (71 ) connected to the shaft of the electrically- operated gear motor in order to transmit the motion from the shaft of the electrically-operated gear motor to the metal ring (72).
9) The coffee grinder (100) of claim 8, wherein said transmission means (71 ) comprise:
- an endless screw (71 a) connected to the shaft of the electrically- operated gear motor (70a), and
- a toothed wheel (71 b) joined to the metal ring (72) and cooperating with the endless screw (71 a) in order to drive the metal ring (72) into rotation.
10) The coffee grinder (100) of any one of the preceding claims, comprising:
- a user interface for inserting a value of the desired distance between the blades;
- a control unit that is electrically connected to the sensor (8), to the user interface and to the actuator (70) of the adjustment device (7),
said control unit being configured in such a way to receive the desired distance value from the user interface, send an activation command to the actuator (70) of the adjustment device (7) in order to change the distance between the two blades (30, 31 ), receive real time information from the sensor (8) on the distance between the sensor (8) and the shaft (42) of the adjustment device, and send an off command to the actuator (70) of the adjustment device (7) when the distance measured by the sensor (8) coincides with the desired distance between the blades (30, 31 ).
PCT/EP2018/078199 2017-10-18 2018-10-16 Coffee grinder with adjustment device of the distance between the blades WO2019076871A1 (en)

Applications Claiming Priority (2)

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IT102017000117981 2017-10-18
IT201700117981 2017-10-18

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070187534A1 (en) * 2003-04-16 2007-08-16 Anson James H Adjustable grinder
US7874505B1 (en) 2007-08-31 2011-01-25 Food Equipment Technologies Company, Inc. Food grinder with electronically adjustable grind settings, tooless disassembly

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070187534A1 (en) * 2003-04-16 2007-08-16 Anson James H Adjustable grinder
US7874505B1 (en) 2007-08-31 2011-01-25 Food Equipment Technologies Company, Inc. Food grinder with electronically adjustable grind settings, tooless disassembly

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