Weighing system for an apparatus able to deliver a predetermined mass, and corresponding method

Abstract

The invention relates to a system (10) for weighing a predetermined mass of a food product, comprising an electric stepping motor (30) supported by a chassis (11) and having an output shaft, a food-product receiving member (22) which is able to move along the axis of travel between a position for receiving and a position for tipping out the food product, and an electronic control unit for controlling the electric motor. According to the invention, the receiving member is unable to move independently of the output shaft and the weighing system is configured so that, in the receiving position, the receiving member and food product apply a static torque to the output shaft, and that the electronic control unit is configured to apply a resistive torque, for a predetermined mass of the food product, to the output shaft so that when the static torque is at least equal to the resistive torque, the output shaft changes position.

Description

[0001] DESCRIPTION

[0002] TITLE: WEIGHING SYSTEM FOR A DEVICE CAPABLE OF DELIVERING A PREDETERMINED MASS AND CORRESPONDING METHOD

[0003] Field of invention

[0004] The present invention relates to a system for weighing a predetermined mass of a food product for an apparatus capable of delivering this predetermined mass in food product. The apparatus is particularly intended for the preparation of a drink such as a baby bottle based on milk powder.

[0005] Technical background

[0006] There are various food weighing systems for beverage preparation. Many weighing systems include a conduit in which extends an auger that is rotated by drive means. Augers are particularly suitable for dosing food powder such as milk powder for preparing baby bottles. The weighing system also includes a hopper into which a quantity of milk powder is supplied and is intended to feed the auger via an opening in the wall of the conduit. The rotation and / or the number of revolutions of the auger in the conduit makes it possible to deliver a predetermined quantity of milk powder to a food product outlet.

[0007] However, the quantity of product delivered by the auger is not precise. Indeed, the delivery of milk powder is carried out on the basis of an average density of the latter without taking into account the particle size or the granular rheology of the powders. Milk powders have different particle sizes and / or densities depending on the nutritional needs of the child. Furthermore, there are large variations in the mass of milk powder actually delivered due to variations in density in the dry state as well as the mass of water absorbed by the powder depending on its storage conditions upstream of the hopper (in the device and outside of it). The presence of moisture in the milk powder considerably modifies its flow. In addition, when the auger stops, a quantity of powder escapes from the terminal section of the auger and is delivered after the auger motor has stopped.All these elements distort the measurement of the mass of milk powder that is delivered. Also known is a milk powder weighing system comprising a measuring chamber and a tray free to rotate about a rotation axis that is installed in the measuring chamber. A hopper is intended to feed the measuring chamber with milk powder. The tray is connected, at one end, to pressure-sensitive powder weighing means that are connected to an electronic control unit. The other end of the tray is connected to stop means. When the mass of powder falling by gravity reaches a value desired by the pressure-sensitive means, the electronic control unit commands the rotation of a stepper motor that carries a cam intended to come into abutment against the stop means. The stop means actuated by the cam then cause the tray to rotate.The quantity of powder is discharged through a discharge port of the measuring chamber. However, the desired quantity of milk powder is not accurate because the measurement does not take into account the different particle sizes, densities and / or granular rheology of the milk powder as stated above. In addition, this system is complex and expensive because it involves several components to measure a precise mass and to deliver this precise mass.

[0008] Other examples of weighing systems are described in documents DE-A1-1549301 and DE-U1-29620108. In document DE-A1-1549301, the weighing system comprises various elements for performing various actions, such as, among others, a rod arranged at a distance from a magnet to determine a mass of a food to be weighed, a member for receiving the food to be weighed which is connected to a counterweight and micro relays to hold the receiving member for a determined time during pouring. The counterweight makes it possible to return the receiving member to position. The distance between the rod and the magnet to determine the mass to be reached is a dimensional quantity. Such a system lacks reliability and is expensive.

[0009] The purpose of the present invention is to provide a weighing system which is accurate, reliable, and economical.

[0010] Summary of the invention

[0011] This objective is achieved in accordance with the invention by means of a weighing system intended to weigh and pour a predetermined mass of a food product, the device comprising:

[0012] - a chassis,

[0013] - a stepper electric motor carried by the chassis and having an output shaft capable of adopting different positions along a movement axis,

[0014] - a food product receiving member which is movable along the axis of movement between a food product receiving position and a food product pouring position, the receiving member being configured to contain or retain a determined mass of the food product in the receiving position and to drop this mass into the pouring position,

[0015] - an electronic control unit intended to control the electric motor, the receiving member being integral in movement with the output shaft and in that the weighing system is configured so that, in said receiving position, the receiving member and the food product that it contains or retains, apply a static torque to the output shaft, and the electronic control unit being configured so as to apply a resistive torque, for a predetermined mass of the food product, to the output shaft so that, when the static torque is at least equal to the resistive torque, the output shaft changes position.

[0016] Thus, this solution makes it possible to achieve the aforementioned objective. In particular, the value of the desired mass when reached induces a static load torque which causes the motor to stall. By "stall" we mean a phenomenon of desynchronization of the rotor of a motor which can occur in the event of an impact or when a torque applied to the motor shaft is equal to or greater than the position-holding torque of the motor. The motor is no longer capable of maintaining the position and slips or stalls which causes an involuntary change of pitch thereof. The invention uses this phenomenon to accurately detect the precise mass of the food product discharged into the receiving member. The implementation and installation of such a system is simple and economical because physical phenomena conventionally occurring in motors are used.The motor torque measurement follows a linear law, which makes this solution an adaptive system. Regarding simplicity, the stepper motor allows several actions / functions to be performed, which are to set the mass to be reached, to hold the receiving member until the determined mass is reached, to tilt the receiving member and to bring it back into position. The stepper motor occupies little space, which makes the system very compact. In addition, the stepper motor allows the adjustment of an electromagnetic quantity, which is much more reliable than a dimensional quantity.

[0017] The system includes the following features taken alone or in combination:

[0018] - the electronic control unit is configured to control the movement of the output shaft and the movement of the receiving member between the receiving position and the discharge position when the mass of food product reaches a predetermined value.

[0019] - the predetermined mass of the food product contained in the receiving member and the receiving member have a center of gravity which is located at a predetermined distance from the axis of movement A.

[0020] - the receiving member comprises connecting means secured to a drive shaft, said drive shaft being coupled in rotation to the output shaft of the rotating mobile electric motor.

[0021] - the receiving organ has the shape of a bucket.

[0022] - the receiving organ has the shape of a receiving wall.

[0023] - the receiving wall has a flat or curved receiving surface.

[0024] - the chassis comprises a platform provided with the opening passing through the wall of the platform on either side and through which the food product is intended to fall by gravity.

[0025] - the weighing system comprises detection means capable of detecting at least one position of the output shaft of the stepper motor, the detection means being connected to the electronic control unit.

[0026] - the predetermined mass is between 3g and 100g.

[0027] - the receiving member is mounted on the output shaft in such a way that the center of gravity of the assembly, formed by the receiving member and the mass of food product, is defined in a plane passing through the axis of movement A which forms a predetermined advance angle with a horizontal plane passing through the axis of movement A of the output shaft.

[0028] - the tilting angle of the receiving member between the receiving position and the tilting position is between 0° and 180°.

[0029] - the weighing system includes a vibrating device intended to allow the total discharge of the food product from the receiving member into the discharge position.

[0030] The invention also relates to an apparatus for preparing a beverage based on a food product, the apparatus comprising a weighing system according to any one of the preceding characteristics.

[0031] According to a feature of the apparatus, the apparatus comprises a food product storage tank and a mixing chamber for receiving a predetermined mass of food product from the receiving member in the pouring position. The invention further relates to a method for weighing and pouring a predetermined mass of a food product by means of a weighing system, the weighing system comprising at least one electric stepper motor having an output shaft and a receiving member which is movably connected to the output shaft, the method comprising the following steps:

[0032] - a stage of supplying a food product,

[0033] - a step of unloading a quantity of food product onto or into the receiving device,

[0034] - a stage of weighing the food product consisting of:

[0035] - - apply a resistive torque for a predetermined mass of the food product, on the output shaft by the electronic control unit,

[0036] -- apply a static torque to the output shaft through the receiving member and the food product it contains or retains, and

[0037] -- change the position of the output shaft of the electric motor when the static torque is at least equal to the resistive torque.

[0038] The method comprises the following steps and / or features taken alone or in combination:

[0039] - the food product contains milk powder.

[0040] - a step of pouring the measured mass of food product.

[0041] - the electronic control unit controls the electric motor.

[0042] Brief description of the figures

[0043] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly on reading the detailed explanatory description which follows, of embodiments of the invention given as purely illustrative and non-limiting examples, with reference to the appended schematic drawings in which:

[0044] [Fig. 1] Figure 1 is a front view of an apparatus for delivering a precise mass of a food product and preparing a beverage with this precise mass according to the invention;

[0045] [Fig. 2] Figure 2 is a perspective view of a system for weighing a precise and determined mass of a food product according to the invention;

[0046] [Fig. 3] Figure 3 illustrates in perspective, substantially below, an example of a food product receiving member according to the invention;

[0047] [Fig. 4] Figure 4 illustrates in perspective, substantially above, an example of a food product receiving member according to the invention; [Fig. 5] Figure 5 represents, in a perspective view, an example of a motor installed on a chassis of a weighing system and means for detecting at least one position of the output shaft of the motor according to the invention;

[0048] [Fig. 6] Figure 6 is a cross-sectional and perspective view of an exemplary weighing system according to the invention;

[0049] [Fig. 7] Figure 7 represents an axial sectional view of the weighing system with a receiving member in a receiving position according to the invention;

[0050] [Fig. 8] Figure 8 is an axial sectional view of the weighing system with a receiving member in the dumping position according to the invention;

[0051] [Fig. 9] Figure 9 illustrates schematically and in axial section another embodiment of a receiving member of a weighing system having the shape of a receiving wall for closing a receptacle according to the invention;

[0052] [Fig. 10] Figure 10 illustrates schematically and in axial section, another embodiment of a receiving member of a weighing system having the shape of a receiving wall for closing a receptacle according to the invention;

[0053] [Fig. 11] Figure 11 is a partial cross-sectional view of the means for detecting positions of the output shaft of the electric motor of the weighing system according to the invention; and

[0054] [Fig. 12] Figure 12 represents the different stages of a method of weighing and pouring a predetermined mass of food product according to the invention.

[0055] Detailed description of the invention

[0056] In Figure 1 is illustrated an apparatus 1 for preparing a beverage based on a food product such as powder, liquid, etc. The food product is preferably, but not limited to, infant milk powder. The apparatus is particularly intended to deliver a precise mass of the food product to prepare the beverage.

[0057] The apparatus 1 comprises a frame 2, a food product storage tank 3 and a water tank (not shown). The frame 2 has a base 5 which is configured to receive a container 6 into which the beverage is poured. The container 6 may be a baby bottle. The food product storage tank 3 is arranged above the base 5 along a longitudinal axis X (here vertical with reference to the plane of FIG. 1 and according to a situation of use of the apparatus arranged on a work surface). The water tank is arranged in the present example downstream of the base 5 along a first transverse axis Y (here horizontal and perpendicular to the plane of FIG. 1). The first transverse axis Y is perpendicular to the longitudinal axis X.In order to be able to weigh and pour a predetermined mass of food product accurately for the preparation of the beverage, the apparatus comprises a weighing system 10 which is described later in this description.

[0058] The predetermined and precise mass of food product is delivered into a mixing chamber 7 into which water at a determined temperature is injected to promote mixing of the food product (here milk powder and water). The water can be injected under pressure. The mixing chamber 7 is arranged between the base 5 and the weighing system 10 along the longitudinal axis X. The mixing chamber 7 comprises a nozzle 8 intended to deliver the beverage and which is arranged at a distance from the base 5. The nozzle 8 is opposite the base 5 along the longitudinal axis X. The nozzle 8 extends along the longitudinal axis from a bottom of the chamber and towards the base. For this purpose, the apparatus 1 comprises a hydraulic circuit (not shown) which comprises a pipe comprising an inlet orifice connected to the water tank and an outlet orifice connected to the mixing chamber 7.The hydraulic circuit comprises a pump for extracting water from the water tank and circulating it in the pipe, as well as means for heating the water. These heating means are arranged on the pipe and are arranged between the pump and the mixing chamber 7.

[0059] The weighing system 10 is shown in Figure 2. The weighing system 10 is described in a situation of installation in the apparatus with an orthogonal reference frame X, Y, T. The weighing system 10 comprises a chassis 11 which is arranged in an enclosure 4 (shown in dotted lines) of the frame 2, the enclosure being located above the mixing chamber 7 along the longitudinal axis X. The chassis 11 comprises a platform 12 with a first surface 13 defined in a plane which is orthogonal to the longitudinal axis X. The chassis 11 comprises feet 14 which make it possible to stabilize the platform 12 and to keep the platform 12 at a distance from a bottom of the enclosure 4. The feet 14 are in the present example four in number. Each foot 14 is elongated along the longitudinal axis between a first end 14a and a second end 14b.The first end 14a carries a sole 15 intended to bear on the bottom of the enclosure 4 and the second end 14b is fixed to the platform 12 by means of fixing members. For this, the platform 12 comprises orifices 16 which each respectively receive the second end 14b of a foot 14. The fixing members comprise nuts which are each force-fitted in an orifice 16 and whose internal thread cooperates with an external thread provided at the second end 14b of each foot. Of course, the fixing members may comprise other fixing members such as studs, screws, glue, welding, etc. The food product storage tank 3 is advantageously mounted on the platform 12. The storage tank 3 determines a storage volume for storing the food product. The platform 12 comprises an opening 17 which passes through the wall thereof on either side along the longitudinal axis X.The storage tank 3 comprises a discharge orifice (not shown) which opens on the one hand into the storage volume of the storage tank and on the other hand into the opening 17 of the platform 12. Advantageously, means for closing (not shown) the discharge orifice are provided to occupy an open position and a closed position of the discharge orifice. These closing means are controlled by an electronic control unit 18 (see figures 1, 6 and 11). The electronic unit is mounted in the apparatus 1 and in particular on the frame 2. The closing means may comprise doors which pivot around an axis parallel to the plane of the first surface 13 of the platform 12 or at least one door sliding in the plane of the first surface 13. We can also see that a hopper 19 extends, along the longitudinal axis X, from a second surface 20 (see figure 5) of the platform 12.The opening 17 opens into the hopper 19 which extends it. In the present example, the hopper 19 has a truncated cross-section (in the plane formed by the longitudinal axes and the first transverse axis Y) which narrows towards an outlet orifice 21 (see figures 5 and 8) of the hopper 19. The outlet orifice 21 of the hopper 19 is opposite (along the longitudinal axis X) the opening 17 defined in the platform 12.

[0060] With reference to Figures 2, 3 and 4, the weighing system 10 comprises a receiving member 22 for the food product supplied by the storage tank 3. This receiving member 22 is movable along a displacement axis between a position for receiving the food product and a position for discharging the food product. Here, the receiving member 22 moves in a rotation around the displacement axis. The receiving member 22 advantageously, but not limited to, has the shape of a bucket. This bucket shape makes it possible to better control the reception of the food product and the contents. In particular, the receiving member 22 comprises a receiving wall 23, two lateral partitions 24 which extend from the lateral edges of the receiving wall 23 and an upstream partition 25 rising from an upstream edge of the receiving wall 23. The receiving wall 23 is here the bottom of the receiving member and is curved.The lateral partitions 24 are opposite each other along a second transverse axis T and comprise internal surfaces 24a defined in substantially parallel planes. The terms “upstream” and “downstream” are defined relative to the first transverse axis Y. The internal surfaces 24a are opposite each other. The upstream partition 25 is also connected to the upstream edges of the lateral partitions 24. The upstream partition 25 comprises an internal surface 25a defined in a plane which is perpendicular to the plane of the internal surfaces 24a of the lateral partitions 24. The upstream partition 25, the two lateral partitions 24 and the receiving wall 23 form a volume for receiving a quantity of food product. At least the upstream partition 25 and the lateral partitions 24 each comprise a free edge 26 delimiting an opening 27 opening into the receiving volume of the receiving member 22.The receiving wall 23 comprises a curved and concave internal surface 23a which is oriented towards the opening 27 of the bucket. The internal surface 23 acts as a surface for receiving the food product.

[0061] In Figures 2, 5 and 6, the weighing system 10 comprises an electric motor 30 intended to drive the movement of the receiving member 22 between the receiving position and the dumping position. The electric motor 30 is carried by the chassis 11 as illustrated. The chassis 11 comprises a housing 31 (and. Figure 6) in which the motor is removably arranged. More specifically illustrated in Figure 6, the chassis 11 comprises a support wall 32 which extends from the second surface 20 of the platform 12 along the longitudinal axis X. The support wall 32 comprises an internal surface 32a which is defined in a plane which is perpendicular to the second transverse axis T. Projections 33 extend from the internal surface 32a of the support wall 32 and at least partially delimit the housing 31 capable of receiving the electric motor 30.These projections 33 have a circular section (along a plane XY (formed by the longitudinal axis X and the first transverse axis Y) and together form a cylindrical wall with an axis parallel to the second transverse axis T. In the present example, there are three projections 33. Alternatively, a single cylindrical wall extends from the internal surface 33a of the support wall 32.

[0062] With reference to figures 3, 4 and 6, the electric motor 30 comprises an output shaft 34 having a displacement axis A which is parallel to the second transverse axis T. The receiving member 22 is integral in displacement with the output shaft 34 of the motor.

[0063] For this purpose and as shown in Figures 3 and 4, the receiving member 22 comprises connecting means 35 to the output shaft 34 of the motor 30. In the present example, the receiving member 22 comprises two lateral wings 36 which extend the lateral partitions 24 downstream. The lateral wings 36 extend substantially along the first transverse axis Y. Each lateral wing 36 comprises an internal surface 36a which is defined in a plane perpendicular to the second transverse axis T. The internal surfaces 36a of the two lateral wings 36 are opposite each other. The connecting means 35 comprise a hollow tube 37 which extends between the two lateral wings 36 of the receiving member 22. A drive shaft 38 is coupled to the output shaft 34 of the motor 30 and is integral in displacement with the output shaft 34. The drive shaft 38 is coaxial with the displacement axis A.The drive shaft 38 is secured to the receiving member 22 so that the latter moves simultaneously with the shaft 38. In particular, the drive shaft 38 is arranged inside the hollow tube 37. The drive shaft 38 has a diameter substantially equal to the internal diameter of the hollow tube 37. According to an alternative not shown, the connecting means 35 comprise lugs connected to the receiving wall 23 and each lug comprises through holes along the second transverse axis T. The drive shaft 38 passes through the lugs and is secured to them so as to be able to cause the receiving member to move.

[0064] The electric motor 30 is a rotary stepper motor or a linear stepper motor. Using a stepper motor is very economical. In this example, the motor 30 is a rotary stepper motor. The output shaft 34 rotates around the axis of movement A. Similarly, the receiving member 22 pivots around this axis of movement A. A stepper motor allows controlled and precise rotation of the output shaft and is simple to control. The stepper motor comprises at least one rotor and one stator. The rotor is coupled to the output shaft 34. The stator carries at least two electric coils or electromagnets that produce a magnetic field. The magnetic field is generated by a current that appears when the motor is supplied with a predetermined voltage. The direction of a magnetic field circulating in the coils of the stators causes the rotor to rotate.The output shaft 34 of the electric motor 30 rotates through a constant angle in response to each electrical pulse, allowing it to adopt different angular positions which are called steps. The motor 30 can have a determined number of steps. The angle can be between 0.9° and 45°. The output shaft 34 of the motor can take between 8 and 400 steps per revolution depending on the motor.

[0065] The electric stepper motor 30 may comprise a permanent magnet stepper motor, a variable reluctance stepper motor or a hybrid stepper motor. Preferably, the electric motor 30 is a hybrid or permanent magnet stepper motor with constant reluctance. The hybrid stepper motor comprises permanent magnets and makes it possible to increase the reluctance torque compared to a stepper motor without permanent magnets. The hybrid motor has a better efficiency and has a lower current requirement to obtain the same torque. The motor 30 is connected to the electronic control unit 18 intended to control the latter. The electronic control unit 18 also makes it possible to power the motor 30. The electronic control unit 18 therefore comprises a power supply module intended to supply the electric motor with voltage and a module for controlling the rotation of the output shaft 34 of the electric motor.The electronic control unit 18 is connected to an electrical energy source such as the domestic network for example by electrical cables of the device 1 (not shown).

[0066] Figure 7 illustrates the receiving member 22 in the receiving position. In this position, the receiving member 22 is configured to contain or retain a determined mass of the food product. The receiving member 22 is of course empty. In this position, the receiving surface (internal surface 23a) of the receiving member 22 is substantially opposite the opening 17 through which the food product is intended to fall by gravity into the receiving member 22. In this example, the free edge is defined in a plane perpendicular to the longitudinal axis and this plane is parallel to a plane P1 passing through the axis of movement A of the output shaft 34. More precisely still, the center of gravity CGV of the empty receiving member 22 is defined in the plane P1 passing through the axis of movement of the output shaft 34.We consider that the plane P1 is horizontal and perpendicular to the longitudinal axis X in the situation of installation of the weighing system 10 in the device 1. The center of gravity CGV of the receiving member 22 is determined by the barycenter of the elements which constitute it. Here the barycenter of the receiving member 22 is equal to the center of gravity CGV.

[0067] Figure 8 illustrates the receiving member 22 in the dumping position. In the dumping position, the receiving member 22 is configured to drop this determined mass. In the dumping position, the receiving surface (internal surface 23a) is at a distance from the opening 17. The receiving wall 23 is opposite and here substantially in contact with the second surface 20 of the platform 12. We see in this figure that the receiving member 22 has pivoted, along the axis of movement A, by a dumping angle substantially of 180° relative to the horizontal plane P1 passing through the axis of movement. The dumping angle is between 0° and 180°. Advantageously, the dumping angle is between 60° and 135°.

[0068] In one embodiment, the weighing system 10 comprises a vibrating device (not shown) intended to allow the total discharge of the food product (or cleaning) from the receiving member 22 in the discharge position. This vibrating device is particularly advantageous when the pivot angle is less than 170° relative to the horizontal plane P1. The vibrating device is electrically connected to the electronic control unit 18 which controls it when the latter is informed of the discharge position.

[0069] According to another embodiment shown schematically in Figure 9, the receiving member 22 comprises the receiving wall 23' which is integral in movement with the output shaft 34 of the electric motor 30. The receiving wall 23' is intended to close or seal a receptacle 47 which is also integral in movement with the output shaft 34 of the motor 30. The receiving wall 23' carries the receiving surface 23a which is intended to receive the food product falling by gravity from the storage tank 3 and for weighing the mass of the food product as described below. The receptacle 47 receives the food product after movement of the receiving wall 23' into the pouring position once the quantity of food product has been weighed. More precisely, the receiving wall 23' is integral in rotation with the output shaft 34 of the motor 30.The receiving wall 23' may be connected directly to the output shaft 34 via connecting means 35 (lugs, hollow tubes) or may be connected to the drive shaft 38 (via the connecting means 35) which is coupled to the output shaft 34. The receptacle 47 has an opening 47a which is delimited by walls 47b and a bottom 47c from which the walls 47b rise. The receiving wall 23' is arranged at the opening 47a to close the receptacle 47. The receiving wall 23' also has dimensions substantially equal to those of the opening 47 while allowing it to tilt inside the receptacle 47 when the mass of food product is reached. The receptacle 47 is arranged above the mixing chamber 7 along the longitudinal axis X. The center of gravity CGV of the receiving member 22 is defined in the horizontal plane P1 passing through the axis of movement A of the output shaft 34.The center of gravity CGV of the receiving member corresponds to the barycenter of the receiving wall 23'. In this example, the receiving surface 23a is flat. However, the receiving surface 23a could have a concave shape to better retain the food product. Such a configuration makes it possible to measure larger quantities of food product.

[0070] The receiving member 22 is made of a polymer material or a composite material with a polymer matrix. An example of a material is a Polycarbonate (PC) or Acrylonitrile Butadiene Styrene (ABS) or a mixture thereof. These polymer materials have the advantage of being very light while being robust. The material can also be a Polypropylene (PP), a Polyoxymethylene (POM), a Polyamide (PA), etc. Generally, a stepper electric motor 30 is subjected to a resistive torque (or reluctance torque) and a synchronous torque. The reluctance torque results from the resistance to the passage of a magnetic flux in the stator and rotor. The electric motor 30 is supplied with a predetermined voltage to maintain each angular position. This predetermined voltage is a function of the resistive torque applied to the output shaft 34 of the electric motor 30.

[0071] The weighing system 10 is configured to determine the mass of the food product by unhooking the motor, i.e. triggering the change of pitch or the angular pivoting while a resistive torque is applied to the output shaft 34 by the electronic control unit 18. For this, the weighing system 10 is configured so that, in said receiving position, the receiving member 22 and the food product that it contains or retains, apply a static torque to the output shaft 34, and the electronic control unit 18 is configured so as to apply a resistive torque to the output shaft 34. In this way, when the static torque is at least equal to the resistive torque, the electric motor 30 (the output shaft 34) changes position. In particular, the resistive torque corresponds to a predetermined mass of the food product.This predetermined mass is the one that must be poured into the mixing chamber 7 to prepare the drink.

[0072] We also understand that controlling the synchronous torque of the electric motor 30 (and the electronic unit) of the weighing system allows for adaptability in the weighing of the food product. In other words, it is possible to modify the mass value to be determined. Indeed, for some weighing systems that use dimensional quantities, the mass to be determined is fixed. Such a weighing system is also much more accurate than a system using dimensional quantities.

[0073] The predetermined mass value is between 3g and 100g. Preferably, the value is 8g.

[0074] According to Figure 7, the receiving member 22 is configured so that the food product 39, here the milk powder, after discharge (from the storage tank 3) forms a slope in or on the receiving member 22. The predetermined mass of food product 39 and the receiving member 22 have a center of gravity CGP which is located at a predetermined distance d from the axis of movement A. The distance d is almost constant. The center of gravity CGP of the assembly is arranged below the center of gravity (CGV) of the receiving member 22 and below the horizontal plane P1 along the longitudinal axis X. The distance d multiplied by the weight of the mass of the assembly (formed by the mass of food product and that of the receiving member), brought back to the center of gravity CGP constitutes a mechanical moment applied to the output shaft 34 of the motor 30. The moment becomes the static torque applied to the output shaft 34 of the motor 30.

[0075] According to an exemplary embodiment shown in Figure 10, the receiving member 22 (with the receiving wall 23') defines a beam having an angle relative to a horizontal plane passing through the axis of movement A of the motor 30. In other words, the receiving member 22 is mounted on the output shaft 34 at a predetermined feed angle a (alpha). This angle a is between 1.8° and 8°. As illustrated, a slope of milk powder is arranged on the receiving surface 23a of the receiving wall 23'. The center of gravity CGT of the slope-shaped food product is arranged above the receiving surface 23a. The point of application of the force F exerted by the slope is defined on the receiving surface 23a and passes through the center of gravity CGV' of the receiving member 22.The receiving member 22 is connected to the output shaft 34 so that the center of gravity of the CGP assembly (powder and receiving member 22) is located above the horizontal plane P1 passing through the axis of movement of the motor. The center of gravity CGP is defined in a plane passing through the axis of movement A which forms the advance angle a with the plane P1. In this way, when the motor stalls, the static torque increases rather than decreases. The moment ( F. * d * cos (a)) increases without increasing the mass of the food product. Such an arrangement improves the sensitivity of the weighing system.

[0076] With reference to Figures 5 and 11, the weighing system 10 comprises detection means 40 capable of detecting at least one angular position of the output shaft 34 of the electric motor 30. The detection means 40 are connected to the electronic control unit 18 which is configured to act on the motor 30 in the event of detection of a change in pitch or angular position of the motor. The detection means 40 comprise an emitter of a light beam (visible or invisible) and a receiver of the light beam. The receiver is arranged opposite the emitter. The emitter and the receiver are connected to the electronic control unit 18. In the present example, the detection means comprise an optical fork 41 comprising a first tab 41a on which the emitter is mounted and a second tab 41b on which the receiver is mounted. The light beam may be an infrared beam.The detection means 40 comprise an obstacle member 42 which is integral with the output shaft 34. This obstacle member 42 is intended to be inserted in the path of the light beam as a function of the angular position of the output shaft 34. In the example shown, the obstacle member 42 comprises a disc with a central axis coaxial with the axis of movement A of the output shaft 34 and integral in rotation with the output shaft 34. In this way, when the motor 30 stalls (the motor changes pitch), the disc pivots at the same time as the output shaft 34. The disc comprises at least a first slot 43 which extends radially from the periphery 44 of the disc towards the central axis of the disc. The slot 43 is intended to be crossed by the light beam (as shown in dotted lines in FIG. 11).For this purpose, the first tab 41 a and the second tab 41 b extend respectively on either side of a portion of the disc 42 along the transverse axis T. The optical fork 41 is installed in a housing 45 which is formed in the platform 12 of the chassis 11. The housing 45 opens onto the first surface 13 and onto the second surface 20 of the platform. A portion of the disc extends through the housing 45 and transversely between the transmitter and the receiver. The obstacle member 42, here the disc, is easy to install and does not introduce any parasitic torque onto the output shaft 34 of the motor. Alternatively, the obstacle member 42 comprises a cam. In particular, when the slot is crossed by the light beam, the electronic control unit 18 controls the maintenance of the position of the output shaft 34 of the motor by applying the resistive torque. In this case, the receiving member 22 is supplied with food product.When the light beam is interrupted, this means that the light beam scans a full surface of the disc and that the output shaft 34 has pivoted at least one step (first angular position). In this case, the electronic control unit 18 controls the output shaft 34 to drive the receiving member 22 into the dumping position.

[0077] The detection means 40 are capable of detecting another angular position (second position) of the output shaft 34 of the electric motor 30. Advantageously, the disc comprises a second slot 46 visible in FIG. 6 intended to allow the detection of the second position of the output shaft 34 and in particular of the receiving member 22. The first slot 43 and the second slot 46 are arranged at 180° from each other. This second slot 46 acts as an end-of-travel detection element of the receiving member 22 in the dumping position.

[0078] We will now describe a method 100 for weighing and pouring a predetermined mass of a food product by means of the weighing system 10 as previously described. The method 100 is illustrated in FIG. 12. The method comprises a step 110 of supplying a food product. In this step, the food product is placed in the storage tank 3 located above the weighing system 10. Preferably, the food product comprises infant milk powder. The method comprises a step 120 of unloading a quantity of food product onto or into the receiving member 22. In particular, the food product is unloaded so as to form a slope on the receiving surface 23a of the receiving member 22. The receiving surface 23a is flat or hollow as previously described.In this step, the electronic control unit 18 sends a control command to the closure means to open the discharge orifice of the storage tank 3. A quantity of food product is thus discharged onto or into the receiving member 22 via the opening 17 of the platform 12 and the hopper 19 which guides the food product towards the receiving member 22. The food product 39 can be guided into the receiving volume of the receiving member 22 in the case of the bucket. The milk powder is poured continuously or discontinuously onto the receiving surface 23a of the receiving member 22.

[0079] The method comprises a step 130 of weighing a predetermined mass of the food product in the receiving member 22. This step 130 consists of unhooking the motor. In particular, the weighing step 130 comprises a sub-step in which the electronic control unit 18 applies a resistive torque to the output shaft 34 of the motor 30. This resistive torque is a function of the supply voltage. For example, a voltage of 12V which corresponds to a resistive torque of 16mNm is applied to the motor 30. This resistive torque corresponds to a mass of powder of approximately 8g. When the receiving member 22 and the food product contained in the receiving member apply a static torque which is equal to the resistive torque, the output shaft 34 pivots and changes pitch.As long as the mass of milk powder in the receiving member 22 (or on the receiving surface 23a) together with the mass of the receiving member does not reach this predetermined value, the milk powder continues to discharge into the receiving member 22.

[0080] The method 100 comprises a step 140 of dumping the weighed mass of powder. In particular, as soon as the mass is reached, the output shaft 34 changes pitch or angular position without action of the motor itself or command from the electronic control unit 18. Simultaneously, the obstacle member 42, here the disc, cuts the light beam between the transmitter and its receiver. The detection means 40 and in particular the optical fork 41 sends a control signal relating to the position of the output shaft 34 to the electronic control unit 18. The latter sends a control order to the motor 30 to drive the rotation of the output shaft 34 and the receiving member 22 into the dumping position. Simultaneously with the dumping step 140 or beforehand, the method comprises a step 150 of stopping the unloading of the food product into the receiving member 22.In this case, the electronic control unit 18 sends a control order to the closing means to close the discharge orifice of the storage tank 3.

Claims

DEMANDS 1. Weighing system (10) intended for weighing and dispensing a predetermined mass of a food product, the device comprising: - a chassis (11), - an electric stepper motor (30) carried by the chassis (11) and having an output shaft (34) capable of adopting different positions along a movement axis (A), - a food product receiving element (22) which is movable along the axis of displacement (A) between a food product receiving position and a food product discharge position, the receiving element (22) being configured to contain or retain a determined mass of the food product in the receiving position and to release this mass in the discharge position, - an electronic control unit (18) intended to control the electric motor (30), characterized in that the receiving member (22) is fixed in movement to the output shaft (34) and in that the weighing system (10) is configured so that, in said receiving position, the receiving member (22) and the food product it contains or retains apply a static torque on the output shaft (34), and that the electronic control unit (18) is configured so as to apply a resisting torque, for a predetermined mass of the food product, on the output shaft (34) so ​​that, when the static torque is at least equal to the resisting torque, the output shaft (34) changes position.

2. Weighing system (10) according to the preceding claim, characterized in that the electronic control unit (18) is configured to drive the movement of the output shaft (34) and the movement of the receiving member (22) between the receiving position and the discharge position when the mass of food product reaches a predetermined value.

3. Weighing system (10) according to any one of the preceding claims, characterized in that the predetermined mass of the food product contained in the receiving member (22) and the receiving member (22) have a center of gravity (CGP) which is located at a predetermined distance (d) from the axis of movement A.

4. Weighing system (10) according to any one of the preceding claims, characterized in that the receiving member (22) comprises connecting means (35) attached to a drive shaft (38), said drive shaft (38) being rotationally coupled to the output shaft (34) of the rotating mobile electric motor (30).

5. Weighing system (10) according to any one of the preceding claims, characterized in that the receiving member (22) has the form of a bucket or a receiving wall (23').

6. Weighing system (10) according to any one of the preceding claims, characterized in that the frame (11) comprises a platform (12) provided with an opening (17) passing through the wall of the platform (12) on both sides and through which the food product is intended to fall by gravity.

7. Weighing system (10) according to any one of the preceding claims, characterized in that it comprises detection means (40) capable of detecting at least one position of the output shaft (34) of the stepper motor, the detection means being connected to the electronic control unit (18).

8. Weighing system (10) according to the preceding claim, characterized in that the predetermined mass is between 3 and 100g.

9. Weighing system (10) according to any one of claims 3 to 8, characterized in that the receiving member (22) is mounted on the output shaft (34) such that the center of gravity of the assembly (CGP) formed by the receiving member (22) and the mass of food product is defined in a plane passing through the axis of movement A which forms a predetermined lead angle with a horizontal plane (P1) passing through the axis of movement A of the output shaft (34).

10. Apparatus (1) for preparing a beverage based on a food product characterized in that it comprises a weighing system (10) according to any one of the preceding claims.

11. Apparatus (1) according to the preceding claim, characterized in that it comprises a food product storage tank (3) and a mixing chamber (7) intended to receive a predetermined mass of food product from the receiving member (22) in the discharge position.

12. A method for weighing and dispensing a predetermined mass of a food product by means of a weighing system (10), the weighing system (10) comprising at least an electric stepper motor (30) having an output shaft (34) and a receiving member (22) which is fixed in movement to the output shaft (34), the method comprising the following steps: - a supply step (110) of a food product, - an unloading step (120) of a quantity of food product onto or into the receiving device (22), - a weighing step (130) of the food product consisting of - to apply a resisting torque for a predetermined mass of the food product, on the output shaft (34) by an electronic control unit (18), -- to apply a static torque on the output shaft (34) by the receiving member (22) and the food product it contains or retains, -- to change the position of the output shaft (34) of the electric motor when the static torque is at least equal to the resistive torque.

13. A method according to the preceding claim, characterized in that the food product comprises milk powder.

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