AU2018300129B2

AU2018300129B2 - Food preparation device and method for controlling same

Info

Publication number: AU2018300129B2
Application number: AU2018300129A
Authority: AU
Inventors: Mickael Beule; Lionnel Durand
Original assignee: SEB SA
Current assignee: SEB SA
Priority date: 2017-07-12
Filing date: 2018-07-09
Publication date: 2021-04-08
Anticipated expiration: 2038-07-09
Also published as: CN110868893A; EP3651624B1; WO2019012216A1; CN110868893B; FR3068874B1; PT3651624T; ES2874635T3; AU2018300129A1; EP3651624A1; FR3068874A1

Abstract

The invention relates to a method for controlling a food preparation device, comprising the steps of: - estimating a parameter representative of a torque provided by a geared motor (51) while the geared motor (51) is being controlled, - comparing the estimation of said parameter with a predetermined threshold, and - preventing the operation of a stirring motor and/or of heating means as long as the estimation of said parameter while the means for securing locking are being controlled remains less than the predetermined threshold for a period of time between a predetermined minimum displacement time and a predetermined maximum displacement time, counted from the generation of a geared-motor control signal.

Description

FOOD PROCESSING DEVICE AND METHOD FOR CONTROLLING SAME

[0001] The present invention relates generally to food preparation devices, and in particular to food preparation devices configured for automatically heating and processing food to be prepared placed beforehand in a processing receptacle by a user. Typically, the invention relates to a food processor comprising a receptacle in which the user places ingredients then closes it with a lid, after which the food processor automatically prepares a dish ready to be served, by heating and processing the ingredients of the processing receptacle.

[0002] It is known in the prior art of food processors, such as that presented in document W02014/026866 Al. The processing device disclosed in that document is complex because it includes a lid which can be blocked on the processing receptacle by longitudinal shafts anchored in a vertical return of the food preparation device. Consequently, it is necessary to provide a complex and robust chassis (which, therefore, forms a swan neck), which is expensive, and bulky. Consequently, access to the processing receptacle is limited by these lateral blocking members, and the usability ergonomics are thereby limited. Finally, the control of the blocking members requires the operation of a geared motor in association with limit switches. These limit switches must be integrated into the chassis structure. Therefore, the overall system is complex and expensive, the control method also being complex, because of the need to manage the switches.

[0003] It is to be understood that, if any prior art is referred to herein, such reference does not constitute an admission that the prior art forms a part of the common general knowledge in the art, in Australia or any other country.

[0004] One or more forms of the present invention aims to ameliorate one or more drawbacks of the prior art.

[0005] A first aspect of the invention relates to a method for controlling the operation of a food processing device, said food processing device comprising: a housing, a receptacle mounted on the housing and configured to receive food to be prepared, at least one mobile processing member positioned in the receptacle and configured for processing the food received in the receptacle, a stirring motor positioned in the housing and configured to set in motion the mobile processing member, a removable lid configured to give the receptacle a closed state in which the receptacle is closed by the lid, means for locking the lid on the receptacle, the lid being configured to be able to be moved when the receptacle is in its closed state between: an unlocked position on the receptacle, in which the lid is released from the locking means, and a locked position on the receptacle, in which the lid cooperates with the locking means, preferably heating means configured to provide cooking heat to the food received in the receptacle, locking securing means of the lid in the locked position, comprising: at least one movable blocking member between a first position in which the movement of the lid from the locked position to the unlocked position is authorized, and a second position in which the blocking member impedes the movement of the lid from the locked position to the unlocked position, a geared motor configured to act on the blocking member so as to allow it to move between its first position and its second position, (or coupled to the blocking member to move the blocking member between the first position and the second position). The control method comprises the steps consisting in: estimating a parameter representative of a torque supplied by a geared motor while the geared motor is being controlled (or means for securing the locking), comparing the estimate of said parameter with a predetermined threshold, and preventing the operation of a stirring motor and/or of heating means as long as the estimate of said parameter, while the locking securing means are being controlled, remains less than the predetermined threshold for a period of time between a predetermined minimum displacement time and a predetermined maximum displacement time, counted from the generation of a geared motor control signal (i.e. its start).

[0006] The food processing device, the operation of which is controlled by the method according to the implementation above, remains simple, since the locked (closed) position of the lid is secured by a blocking member (a rod) which prevents any relative rotation between the receptacle and the lid. The lid cannot be maneuvered to open the receptacle, and the rod is a simple member to move, without exerting a force on the lid (since the latter is already coupled and locked with the receptacle). In summary, during use, the lid is first placed on the receptacle by the user to close it (the lid is in the unlocked position), then, while the receptacle is still closed, the lid is moved by the user to go to the locked position (by the locking means), and it can then be blocked in this position by the locking securing means (the rod).

[0007] The method according to the above implementation ensures that the lid is in the locked position without the need to install limit switches, because an estimate of a representative torque parameter is made and no control is authorized if a torque increase does not take place within a predetermined time interval. In other words, operation is prohibited if the geared motor does not provide any torque representative of a limit switch at an expected time. In the present application, estimating a parameter means determining a value of this parameter, for example, by one or more measurements and possible calculation in order to be able to compare the estimate (the value) of the parameter monitored with a predetermined threshold.

[0008] Advantageously, the locking means for the lid on the receptacle are of the bayonet type. Such locking means are practical and allow a locking action simultaneously with the displacement of the lid towards the locked position. It should be noted that the locking means are distinct from the locking securing means. In particular, the lid is moved from its unlocked position to the position locked by the user, where it is locked by a blocking member (a bayonet, for example). Only then the blocking member of the locking securing means cooperates or engages with the lid to block it. In other words, the blocking member is not part of the locking means.

[0009] Advantageously, the operation of the stirring motor and/or the heating means is authorized if, during a control of the locking securing means, the estimate of the parameter is greater than the predetermined threshold at an instant between an intermediate time and the predetermined maximum displacement time, the intermediate time being between the predetermined minimum displacement time and the predetermined maximum displacement time. The intermediate time is greater than the minimum displacement time, and less than the maximum displacement time. Between the intermediate time and the maximum displacement time, it suffices that the torque provided exceed a control (and, consequently, that the parameter exceed the threshold) between this intermediate time and the maximum displacement time to authorize the operation of the food processing device (stirring motor and/or heating means). As an additional condition, it may be envisaged to authorize the operation of the food processing device (stirring motor and/or heating means) only if the torque supplied exceeds a peak long enough, or after two or more estimates (or measurements) greater than the threshold.

[00010] Advantageously, the operation of the stirring motor and/or of the heating means is authorized if, during a control of the locking securing means, the estimate of the parameter is greater than the predetermined threshold and if a variation of said parameter as a function of time is greater than a predetermined slope, at an instant between the predetermined minimum displacement time and the intermediate time. According to this implementation, between the minimum displacement time and the intermediate time, two conditions must be fulfilled to authorize the operation of the food processing device (stirring motor and/or heating means): exceeding a threshold, and exceeding a threshold speed of force rise. Indeed, the Applicant noticed that if the lid was incorrectly positioned (the lid is between the unlocked position and the locked position), then the control member cannot go to its second position, but abuts in the process of displacement against the incorrectly positioned lid and pushes the latter, which causes the torque peak to be exceeded, but with a low force rise speed. Consequently, in order to distinguish this case from the case of securing rapid locking with a properly positioned lid, it is necessary to impose, for the instants between the minimum displacement time and the intermediate time, a force or torque threshold condition, but also a force variation speed threshold condition or the torque supplied by the geared motor.

[00011] Advantageously, the estimation of the parameter is not carried out or taken into account before a predetermined preliminary time, such as 100 ms, counted from the generation of a control signal (start-up) of the geared motor. Indeed, between start-up and the previous time, the acceleration of the motor may lead to a torque similar to a torque supplied at the end of travel. In order not to erroneously conclude that a blockage has occurred, the evolution of the parameter is not taken into account at the very beginning of the start-up.

[00012] Advantageously, if, during a control of the locking securing means, the estimate of the parameter is greater than a second predetermined threshold, less than or equal to the predetermined threshold, at an instant between the predetermined previous time and the predetermined minimum displacement time, counted from the generation of a control signal (of the start-up) of the geared motor, then a blocking counter is incremented by a value of 1. If after the acceleration phase, the torque supplied increases before the minimum displacement time, this means that there is a blockage. The method can then stop feeding the geared motor to avoid overheating, and a blocking counter is incremented.

[00013] Advantageously, the control method also includes a step consisting in sending blocking information to the user, if the blocking counter is incremented. The information can be the lighting of an indicator light, or the emission of an alert sound. This allows the user to verify the assembly of the food processing device and/or to attempt to launch a geared motor control in the same direction or in the opposite rotational direction.

[00014] Advantageously, the control method includes a step consisting in automatically controlling a change of rotational direction of the geared motor, simultaneously or after the step of incrementing the blocking counter. The food processing device then automatically attempts to return the geared motor and the control unit to the initial configuration.

[00015] Advantageously, the locking securing means of the lid are considered to be in a blocked state if the blocking counter exceeds the value of 3. The method can then include a step of cutting off the current supply, putting the unit out of service, or informing the user.

[00016] Advantageously, the locking securing means of the lid are considered to be in a normal operating state if the blocking counter is not incremented following a subsequent check, the method then comprising a step of resetting the blocking counter to zero.

[00017] Advantageously, the estimate of the parameter is deduced from measurements synchronized with a control signal from the geared motor.

[00018] Advantageously, the parameter representative of the torque supplied by the geared motor is an electric current consumed by the geared motor. In particular, it may be possible to measure an intensity traversing a resistor mounted in series with the geared motor. It may also be possible to measure a voltage at the terminals of such a resistor mounted in series with the geared motor. All these measured parameters give a measurement or an image of the current consumed and, therefore, of the torque supplied by the geared motor.

[00019] Advantageously, the geared motor is supplied with a direct current. In other words, the control signal of the geared motor is a direct current, with a voltage sometimes positive or sometimes negative, depending on the rotational direction to be imparted to the geared motor.

[00020] Advantageously, the estimate of the current consumed by the geared motor is obtained by calculating an average value resulting from a sampling of values of the supply current of the geared motor during a control phase of the geared motor.

[00021] Alternatively, the geared motor is supplied with a square control signal. Such a square signal is also called a square wave signal, or "all or nothing" supply. I.e., it consists of an alternation of high ranges and low or zero ranges (in voltage and/or in intensity).

[00022] Advantageously, the estimate of the current consumed by the geared motor is obtained by calculating an average value resulting from a sampling of current values during two successive high pulses supplying the geared motor.

[00023] Advantageously, the sampling frequency is 500 Hz.

[00024] Advantageously, the operation of the stirring motor and/or the heating means is prohibited if, during a control of the locking securing means, the estimate of said parameter: - is greater than the second predetermined threshold at an instant between the previous time and the minimum displacement time, - remains below the predetermined threshold throughout the control of the locking securing means (i.e., from the previous time, and even after the maximum displacement time, because without torque supplied, this may mean that the geared motor is broken down, or the control unit is uncoupled, which implies a non-securing of the locked position of the lid).

[00025] If it is necessary to secure the locking of the lid, it may also be possible to prohibit the operation of the stirring motor and/or heating means from the start of the control of the geared motor until the minimum displacement time, and provided that it occurs between the minimum displacement time and the maximum displacement time. Likewise, when lifting the lid locking securing means, provision may be made to prohibit the operation of the stirring motor and/or the heating means from the start of the control of the geared motor until the minimum displacement time, and provided that it occurs between the minimum displacement time and the maximum displacement time.

[00026] A second aspect of the invention relates to a food preparation device comprising: - a housing, - a receptacle mounted on the housing and configured to receive food to be prepared,

- at least one mobile processing member positioned in the receptacle and configured for processing the food received in the receptacle, - a stirring motor positioned in the housing and configured to set in motion the mobile processing member, - a removable lid giving the receptacle a closed state in which the receptacle is closed by the lid, - locking means for the lid on the receptacle, - the lid being configured to be displaced when the receptacle is in its closed state between: - an unlocked position on the receptacle, in which the lid is released from the locking means, and - a locked position on the receptacle, in which the lid cooperates with the locking means. The food processing device further includes: - preferably heating means configured to provide cooking heat to the food received in the receptacle, - locking securing means of the lid in the locked position, comprising: at least one blocking member, such as a rod comprising a blocking portion, movable between a first position in which the movement of the lid from the locked position to the unlocked position is authorized, and a second position in which the blocking portion impedes the movement of the lid from the locked position to the unlocked position, a geared motor coupled to a control arm configured to move the blocking member between the first position and the second position, - means for controlling the operation of the locking securing means of the lid, - control means for the geared motor configured to either secure the locking by bringing the blocking member to its second position, or remove the securing of the locking by bringing the blocking member to its first position, the control means being configured for: - estimating a parameter representative of a torque supplied by the geared motor during a control of the geared motor by the control means, - comparing the estimate of said parameter representative of the torque supplied with a predetermined threshold, and - prohibiting the operation of the stirring motor and/or the heating means as long as the estimate of said parameter during a control of the geared motor remains below the predetermined threshold in a time interval between a predetermined minimum displacement time and a predetermined maximum displacement time, counted from the generation of a control signal from the geared motor (i.e. its start-up).

[00027] Advantageously, the stirring motor is a DC motor.

[00028] Advantageously, the housing includes: - a first stop configured to cooperate with a first element integral with the control arm so as to define the first position of the blocking member, - a second stop configured to cooperate with a second element integral with the control arm so as to define the second position of the blocking member.

[00029] In other words, the food processing device includes: - a first stop connected to the housing and configured to define the first position of the blocking member, - a second stop connected to the housing and configured to define the second position of the blocking member.

[00030] In other words, the removable lid is configured to close the receptacle, and when the rod is in the first position, the blocking portion is released from the lid in the locked position, and in the second position, the blocking portion of the rod is engaged with the lid in the locked position.

[00031] Advantageously, the blocking member is a rod. However, it is possible to provide a blocking member separate from the rod, such as a pivoting blocking member relative to the receptacle or to the housing (a rocker, for example). The blocking member may be directly moved by the geared motor, or by means of a transmission device. If desired, the blocking member may be associated with an elastic return means configured to bring said blocking member to the first position, to the second position, or to another position.

[00032] A third aspect of the invention relates to a method for controlling a food preparation device comprising: - a housing, - a receptacle mounted on the housing and configured to receive food to be prepared, - at least one mobile processing member positioned in the receptacle and configured for processing the food received in the receptacle, - a stirring motor positioned in the housing and configured to set in motion the mobile processing member according to several processing speeds, - a removable lid giving the receptacle a closed state in which the receptacle is closed by the lid,

- locking means of the lid on the receptacle, - the lid being configured to be moved when the receptacle is in its closed state between: - an unlocked position on the receptacle, in which the lid is released from the locking means, and - a locked position on the receptacle, in which the lid cooperates with the locking means, - preferably heating means configured to provide cooking heat to the food received in the receptacle, - locking securing means of the lid, the control method comprising the steps consisting in: - automatically activating the locking securing means during a start-up of the food processing device, so as to block the lid in the locked position, - activating the locking securing means so as to unblock the lid: • simultaneously with a shutdown of the food processing device, if a measured temperature of the receptacle or the food to be prepared is below a predetermined temperature, or if a set temperature used before the shutdown of the food processing device is below a predetermined temperature, or if the processing speed used before the shutdown of the food processing device is lower than a predetermined speed, • at the end of a rest delay counted from a shutdown of the food processing device, if a temperature of the receptacle or the food to be prepared is higher than the predetermined temperature, and if the processing speed used before the shutdown of the food processing device is greater than a predetermined speed.

[00033] When lifting the lid locking securing means only after the rest delay if the food is hot and has been strongly agitated, the above method allows to secure the use of the device. Indeed, the enclosure remains closed and the lid blocked in the locked position if there is a risk of overflow or boiling, after significant heating/stirring. The rest of the time, the lid can be removed immediately after shutdown, which limits unnecessary waiting times (since below the predetermined temperature or the predetermined speed, there is no risk of overflow or untimely boiling).

[00034] Advantageously, the temperature of the receptacle or the food to be prepared is measured or estimated before or simultaneously with the end of the preparation of the food. In other words, the temperature of the receptacle or the food to be prepared is estimated or measured at least during the last moments of preparation (in the last minute or in the last thirty seconds, or during the last stage of the food preparation program) in order to know whether or not to secure the locking of the lid after shutdown of the processing unit and/or the heating means. The device may include a temperature probe, or take into account the temperature set point used during the food preparation program.

[00035] Regarding the processing speed, the device can measure or estimate it before or simultaneously at the end of the food preparation. In other words, the processing speed is estimated or measured at least during the last moments of preparation (in the last minute or in the last thirty seconds or during the last step of the food preparation program) in order to know if it is necessary to secure or not the locking of the lid after the shutdown of the processing unit and/or the heating means. The device may include an encoder, or take into account the processing speed setpoint used during the food preparation program. However, the temperature of the receptacle or food to be prepared and the processing speed are not necessarily estimated or measured at the same point tin time, nor simultaneously.

[00036] A variant of the third aspect of the invention relates to a method for controlling a food preparation device comprising: - a housing, - a receptacle mounted on the housing and configured to receive food to be prepared, - at least one mobile processing member positioned in the receptacle and configured for processing the food received in the receptacle, - a stirring motor positioned in the housing and configured to set in motion the mobile processing member according to various processing speeds, - a removable lid giving the receptacle a closed state in which the receptacle is closed by the lid, - locking means for the lid on the receptacle, - the lid being configured to be displaced when the receptacle is in its closed state between: - an unlocked position on the receptacle, in which the lid is released from the locking means, and - a locked position on the receptacle, in which the lid cooperates with the locking means, preferably heating means configured to provide cooking heat to the food received in the receptacle, locking securing means of the lid in the locked position, the control method comprising the steps of: conditionally activating the locking securing means during a start-up of the food processing device, or after the start-up of the food processing device, so as to block the lid in the locked position, only if a temperature measurement of the receptacle or food to be prepared is greater than a predetermined temperature, or if a set temperature used before the shutdown of the food processing device is greater than a predetermined temperature, and if the processing speed used is greater than a predetermined speed, activating the locking securing means so as to unblock the lid at the end of a rest delay counted from a shutdown of the preparation device, if the locking securing means have been previously activated so as to block the lid in the locked position.

[00037] The method according to the implementation above secures the use of the device: the securing of the locked position of the lid is only activated if the food is going to be highly heated and stirred during the preparation, and will be subsequently unlocked only at the end of the rest delay. In all other cases, the lid is not blocked in the locked position.

[00038] Advantageously, the temperature of the receptacle or of the food to be prepared is measured or estimated before or simultaneously at the end of the food preparation. In other words, the temperature of the receptacle or of the food to be prepared is estimated or measured at least during the last moments of preparation (in the last minute or in the last thirty seconds or during the last stage of the food preparation program) in order to know whether or not to secure the lid locking. The device may include a temperature probe, or take into account the temperature set point used during the food preparation program. Provision may also be made to launch conditional locking on the basis of the temperature projected in a future cycle, even before the receptacle or food reach that temperature.

[00039] Regarding the processing speed, the device may measure or estimate it before or simultaneously at the end of the food preparation. In other words, the processing speed is estimated or measured at least during the last moments of preparation (in the last minute or in the last thirty seconds or during the last stage of the food preparation program) in order to know whether or not to secure the lid locking. The device may include an encoder, or take into account the processing speed setpoint used during the food preparation program. Provision may also be made to launch conditional locking on the basis of the processing speed projected in a future cycle, even before the mobile processing member is rotated. However, the temperature of the receptacle or food to be prepared and the processing speed are not necessarily estimated or measured at the same point in time, nor simultaneously.

[00040] Advantageously, the rest delay is greater than or equal to 5 seconds, and preferably greater than or equal to 10 seconds.

[00041] Advantageously, the predetermined temperature is less than or equal to 60 °C and, preferably, less than or equal to 50 °C, and the predetermined speed corresponds to a rotational speed of the mobile processing member less than or equal to 250 rpm, and preferably less than or equal to 160 rpm.

[00042] Advantageously, the processing speed is a set speed to be imposed on the mobile processing member during the pre-established operating program, or the processing speed is a measured speed of the mobile processing member, using an encoder, for example.

[00043] Advantageously, the shutdown of the food processing device is a shutdown of the movement of the processing member and/or a shutdown of the heating of the receptacle.

[00044] Advantageously, the control method comprises, after the start-up of the food processing device, at least one step consisting in heating the food to be processed and at least one step consisting in processing the food to be prepared with the mobile processing member.

[00045] Advantageously, the control method comprises, after the start-up of the food processing device, at least one step consisting of mixing, or kneading, or beating, or cutting, or chopping the food to be prepared.

[00046] Typically, for a food processing device such as that which is the subject matter of the invention, a rotational speed of the mobile processing member is in a range from 0 to 300 rpm (or min-), for example, and preferably between 0 and 200 rpm. Advantageously, the predetermined speed is, for example, a speed which is in the range of [70% -100%] and preferably [80% -100%] of the maximum speed of the total speed range indicated above. In other words, the locking of the lid is secured for any speed greater than, for example, 160 rpm and preferably for any speed greater than 250 rpm, if the temperature is above 50 °C or 60 °C, which prevents any opening of the processing enclosure if a risk of boiling or overflow is present, even after the shutdown of the stirring motor driving the mobile processing unit.

[00047] Other characteristics and advantages of the present invention will appear more clearly upon reading the following detailed description of an embodiment of the invention given by way of non-limiting example and illustrated by the accompanying drawings, wherein: - Figure 1 shows an exploded perspective view of a food processing device according to the present invention, comprising a housing, a receptacle and a lid; - Figure 2 shows a partial section of part of the housing of the food processing device of Figure 1 without the receptacle, to show a geared motor coupled to a rod occupying a first position and being part of the locking securing means of the lid of the food processing device; - Figure 3 shows the partial section of Figure 2, with the geared motor having pushed the rod which occupies a second position; - Figure 4 shows a diagram of the current consumed by the geared motor during the passage of the rod from the first position to the second position, during normal operation; - Figures 5 to 7 show diagrams of the current consumed during abnormal operations or in the event of untimely blocking of the geared motor and/or the rod; - Figure 8 shows a supply signal of the geared motor; - Figures 9a and 9b show a perspective view of the geared motor; - Figure 10 represents a perspective view of part of the food processing device.

[00048] In the following detailed description, reference is made to accompanying drawings which form a part of the detailed description. The illustrative embodiments described in the detailed description, depicted in the drawings and defined in the claims, are not intended to be limiting. Other embodiments may be utilised and other changes may be made without departing from the spirit or scope of the subject matter presented. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings can be arranged, substituted, combined, separated and designed in a wide variety of different configurations, all of which are contemplated in this disclosure.

[00049] Figure 1 shows a food preparation device with a housing 40, removably receiving a receptacle 10 which can contain a mobile processing member 30 and be closed by a lid 20. The mobile processing member, here a cutting tool, is placed in the receptacle 10, and is then coupled with a stirring motor located in the housing 40, to be driven in rotation, once the receptacle 10 is closed with the lid 20.

[00050] The receptacle 10 has two lateral extensions 11 which rise along the receptacle 10, and which end in two handles 12 at the upper part of the receptacle 10, each comprising a slot 13. The lid 20 is provided to be mounted on the receptacle 10 in a rotational movement (a pivot connection is provided), in order to engage a male part of the lid 20 in the slots 13, passing from an unlocked position to a locked position in which the lid 20 is in position final on the food processing device This locking system is, for example, a bayonet locking.

[00051] In other words, the lid 20 in the unlocked position closes the receptacle 10, and can be removed therefrom freely, but can no longer be lifted from the receptacle 10 once it has been moved to the locked position, which provides safety in use when the mobile processing member 30 is rotating in the receptacle 10. The bayonet-type locking means mentioned above may be elastic, i.e. that the user, by lifting the lid, moves it past a "notch" so that a flexible latch of the bayonet locking means forms an obstacle to a backflow when in use. When the preparation is finished, the user, by turning the lid 20 in the opposite direction, unlocks the bayonet-type locking means by forcing the lid to move past the "notch" again, and can remove the lid 20 by completing its rotation.

[00052] The food processing device can also include heating means for heating and/or cooking food to be prepared. It is typically a heating resistor placed in the housing , on the housing 40, on the receptacle 10, or in the latter.

[00053] Typically, food to be prepared is placed in the receptacle 10 with the mobile processing member 30, the lid 20 is placed on the receptacle 10 to close it, then it is pivoted to go from the unlocked position to the locked position, and a predetermined preparation program is selected by the user on a control panel 44 of the housing 40. The food processing device may include detection means (presence sensors) which indicate that the receptacle 10 is in place, and that the lid 20 is correctly in the locked position, before starting the preparation, by heating and/or processing the food to be prepared.

[00054] During this preparation, a rotational speed of the mobile processing member may be imposed in a speed range from 0 to 300 rpm (300 min-), in stages, in a variable or constant manner. The stirring motor located in housing 40 is fitted with a reduction gear, and its speed is then defined according to the reduction ratio. With respect to the heating means, they can impose on the food to be prepared a temperature of up to 130 °C, for example.

[00055] Depending on the program selected, and in particular when a risk of overflow of hot product is identified, it must be possible to block the lid 20 in the locked position, even if it is already locked in position by the locking means described above.

[00056] Consequently, the food processing device according to the present invention comprises locking securing means of the lid in the locked position, highlighted in Figures 2 and 3 which are a partial section of the food processing device along the axis A-A in Figure 1.

[00057] The locking securing means include, in particular, a blocking member which is here a rod 52 housed in one of the lateral extensions 11 of the receptacle 10, and a geared motor 51 (a DC motor, for example) coupled to a control arm 51a (a rack) in order to make the rod 52 slide with respect to the housing 40 and the receptacle 10. In the present case, the rod 52 is mounted in sliding connection on the receptaclelO.

[00058] However, making the rod 52 integral with the housing 40 by adding, for example, a housing extension which goes up to the lid may be a possible alternative.

[00059] In Figures 1 and 2, the rod 52 is flush with the upper surface of the handle 12, which it does not exceed. The rod 52 is in a first position in which the lid 20, which closes the receptacle 10, can be freely pivoted relative to the receptacle 10. The locking securing means are said to be "deactivated".

[00060] In Figure 3, the rod 52 has been moved up by the geared motor 51, which makes it exceed by a height d relative to the handle 12, to insert the extremity (a portion of blocking or engagement) of the rod 52 in a female shape of the lid 20, in order to block the only degree of freedom (rotation) of the lid 20, which is consequently blocked in the locked position. The user cannot pivot the lid 20 to remove it from the receptacle 10 as long as the rod 52 is in the second position. The locking securing means are said to be "activated".

[00061] The second position of the rod 52 is defined by a first mechanical stop between the control arm 51a and the housing 40, so as not to exert forces on the lid 20 in the locked position. However, if the lid 20 is incorrectly locked and the geared motor 51 still launched, the rod 52 will come to a stop on the incorrectly positioned lid 20.

[00062] In order to return the rod 52 in the first position, it is again necessary to control the geared motor 51 so that it lowers the control arm 51a to a second stop, and a spring return may be provided to maintain contact between the rod 52 and the control arm 51 and thus facilitate the return of the rod 52 to its first position. It is also possible to provide a coupling between the control arm 51a and the rod 52 which guarantees that any movement of the control arm is transmitted to the rod 52, to make it move from the first position to the second position, but also from the second position to the first position. A dovetail or T-groove joint with coupling during a rotational mounting movement of the receptacle 10 on the housing 40 may allow this function. Thus, by following the movement of the geared motor 51 and the abutment by means of the control arm 51a on the housing , the position of the rod 52 is guaranteed.

[00063] Figures 9a and 9b show a view from two points of view of the geared motor 51, which includes the control arm 51a which comprises a rack 51b, and an electrical connector 51e. The control arm 51a forms a pinion-rack link with the geared motor 51, and is guided in sliding connection by the plastic housing of the geared motor 51. The assembly is then compact, and the control arm 51a has two stops, 51c and 51d, which are each configured to come into abutment with a portion of the housing 40 to ensure a precise end-of-travel stop for the system. The stop 51c ensures the upper end-of-travel abutment (rod 52 in second position) and the stop 51d ensures the low end-of-travel abutment (rod 52 in its first position).

[00064] Figure 10 shows a partial perspective view of part of the food processing device, where the geared motor 51 is configured in the housing 40, with the upper part of the control arm 51a which is flush with the housing 40. Thus, when the user couples the receptacle 10 (with the rod 52 housed in the lateral extension 11) on the housing 40, the rod 52 is facing the control arm 51a, ready to be pushed upwards if it is necessary to secure the locking of lid 20.

[00065] When generating a control signal from the geared motor 51 to bring the rod 52 from the first position to the second position, or vice versa, the geared motor 51 provides torque and consumes current, and the method for controlling the operation according to the invention proposes to follow the variation in torque to check whether the rod 52 is in the correct position (which prevents the lid 20 from turning again) in order to authorize subsequent operation of the stirring motor and/or heating means.

[00066] To this end, it is proposed to follow a parameter representative of the torque supplied by the geared motor 51, such as the current consumption. The current consumed passing through a resistor mounted in series with the geared motor can be measured, as can be the voltage across such resistance 51. In any event, an estimation is carried out (i.e., based on at least one measurement) of this parameter when controlling the geared motor 51, and the estimated value is then compared with a predetermined threshold value S1.

[00067] As shown in Figure 4, the estimated value of this parameter (here the current or the intensity of the current) is monitored over time, from the start-up of the geared motor 51 (i.e., from the moment it is currented).

[00068] At the start of operation, between 0 and a previous time Tp, the geared motor sets in motion and consumes a relatively high inrush current. Then, consumption becomes lower, because only the friction of the mechanism is to be overcome. Finally, between a minimum displacement time Tm and a maximum displacement time TM, and, in particular, after an intermediate time Ti, there is a peak of current which exceeds the threshold value S1. This current flow corresponds to a rise in torque supplied by the geared motor 51 because the mechanism arrives at the mechanical end-of-travel stop (the arm 51a abuts directly against the housing 40 or an integral support of the latter, but it may be possible, as an alternative, to provide that it is the rod 52 in the second position which abuts against the lid 20, or against the housing 40 or a support integral with the latter).

[00069] The minimum displacement time is, for example, calculated as being the time taken by a geared motor having a rotational speed in high tolerance limit, to move the rod 52 on a course in low tolerance limit. Statistical calculations may also be carried out to fix the time limit below which the rod 52 cannot be in the final position.

[00070] In any event, between Ti and TM, the estimate (the estimated value) of the parameter exceeds the threshold S1, and then the method can cut the power supply to the geared motor 51, and authorize the subsequent operation of the food processing device (control of stirring motor and/or heating means).

[00071] In order not to erroneously authorize the subsequent operation of the food processing device (control of the stirring motor and/or heating means), the estimate of the current is not taken into account between the start-up and the previous time Tp, since this is the normal acceleration of the geared motor, while the rod 52 is not correctly positioned. In other words, the method prohibits the subsequent operation of the food processing device (control of the stirring motor and/or heating means) between the start-up and the time previous Tp. In addition, not taking into account such an initial current peak also makes it possible not to distort a calculation of average current value if, for example, a sampling is carried out with calculation of an average current value to compare this average value with a subsequent current peak during the expected blocking.

[00072] Figure 5 shows a case where the user has not correctly positioned the lid in the locked position (it is engaged on the receptacle 10 but not sufficiently pivoted), but the user has still initiated the operating cycle. During the control of the geared motor 51, the latter pushes the rod 52 which comes out of the lateral extension 11, but the rod 52 then comes into abutment on the lid 20 and pushes it. It can be seen that the current peak quickly exceeds the threshold value, i.e., between the minimum displacement time Tm and the intermediate time Ti. However, if the force ascent rate (illustrated by the curve in a dotted line) is compared to it, it shows that the slope or the variation as a function of time is lower in the case where the lid 20 is incorrectly positioned than in the case where the lid 20 is correctly positioned. Indeed, in case of correct positioning, the current rise is faster because the mechanism arrives at a precise and normal stop.

[00073] In the case where the current estimate exceeds the threshold S1 between the minimum displacement time Tm and the intermediate time Ti, the control method authorizes subsequent operation of the food processing device only if the estimated value exceeds the threshold S1, and if the slope, or the speed of variation, exceeds a predetermined slope. This makes it possible to distinguish a fast geared motor in the case of a correct assembly, from a slower geared motor, but with an incorrect assembly, and a stop intervening during displacement of the rod 52.

[00074] Figure 6 represents the case of a blockage (of the geared motor 51 and/or the rod 52 and/or the arm 51a), because one can observe a current peak which exceeds the threshold S1, before the minimum displacement time Tm. In this case, one can conclude that the system was blocked before the rod 52 secured the locking of the lid 20. However, as an advantageous alternative, in the time range between the previous time Tp and the minimum displacement time Tm, it is entirely possible to declare a blockage as soon as the estimated value exceeds a second threshold S2, represented in Figure 6, and less than S1, to detect such a blockage more quickly.

[00075] The method can perform the following steps: indicate a blockage to the user, attempt to start the geared motor in another rotational direction, increment a blocking counter, stop powering the geared motor. In any event, the subsequent operation of the food processing device (control of the stirring motor and/or heating means) is prohibited.

[00076] In the case where the method or the user attempts to restart the geared motor in the other rotational direction and the latter remains blocked (current peak greater than S1 before the minimum displacement time Tm), then the blocking counter is further incremented. If this blocking counter exceeds 3, the system is considered to be completely blocked and the method can cut off all power, until repair, for example.

[00077] Figure 7 represents a case of breakdown, in which the geared motor 51 consumes a limited amount of current, which remains below the threshold S1 throughout the control. In this case, the rod 52 is not even moved, and the method consequently prohibits subsequent operation of the food processing device (control of the stirring motor and/or the heating means). A display step of a message intended for the user, recommending he contact an after-sales or maintenance service, may also be provided, for example.

[00078] Typically, the geared motor 51 is supplied with a direct current, with a positive voltage to impose a first rotational direction, or else a negative voltage to impose a second rotational direction. The method then estimates the current consumed by the geared motor during the control and supply phases of the geared motor.

[00079] However, as an alternative, Figure 8 represents a supply signal of the geared motor 51 which is, in this particular case, an all or nothing type signal, which, therefore, presents a succession of high ranges and low ranges (which can be equal to zero). It can be called a square control or a square wave signal. In this particular case, the method synchronizes the measurement of the parameter indicative of the torque (here, the current) with the high ranges of the control signal. In addition, as shown by the arrows, several measurements can be made during the same high range in order to form a sampling. For example, it is possible to provide a 50 Hz control signal frequency and a 500 Hz sampling frequency, only when the control signal is in a high range. Averages of the measurements can then be performed, for example, on two successive high pulse ranges.

[00080] If the geared motor is a 0.98 W DC motor powered at 24V with a nominal total displacement time of 550 ms, the following values can be given, by way of example: Previous time Tp = 100 ms Minimum displacement time Tm =300 ms Intermediate time Ti = 480 ms Maximum displacement time TM= 2 s Threshold S1 = 100 mA Threshold current slope: 1.30 mA/ms

[00081] Of course, these values are examples, and may be adjusted according to the characteristics of power, speed and stroke of the geared motor and the rod and, more generally, according to the size of the device.

[00082] As mentioned above, blocking the lid in the locked position only occurs if a risk of overflow of hot product is identified. In particular, the food processing device according to the present invention can implement a control method in which the locking securing means of the lid in the locked position are only controlled if a rotational speed of the mobile processing member is higher than a predetermined speed, and if the temperature of the food to be prepared is higher than a predetermined temperature.

[00083] According to a first variant of this method, the locking securing means may be systematically activated to always block the lid 20 in the locked position, and the locking securing means, activated after the shutdown, maintained during a rest delay (at least five seconds, and preferably at least eight or ten seconds), only if during the preparation cycle, the rotational speed of the mobile processing member is (or was) higher than a predetermined speed, and if the temperature of the food to be prepared is (or has been) higher than a predetermined temperature. The user must then wait for the end of the rest delay before being able to open the lid 20. If these two conditions have not been met simultaneously, the deactivation of the locking securing means is simultaneous with the shutdown of the food processing device and the user can immediately open lid 20.

[00084] In other words, according to this variant, the blocking of the lid 20 in the locked position is systematic, and the unlocking is carried out either immediately or simultaneously at the shutdown of the food processing device, if no risk of overflow is identified, or is delayed, if a risk of overflow is identified (predetermined temperature exceeded and predetermined speed exceeded). In other words, the locking securing means are conditionally disabled.

[00085] According to a second variant of this method, the lid 20 may be blocked in the locked position only if the two conditions are programmed (i.e., at the start-up of the food processing device, for example simultaneously with mobile processing member movement start-up or even after, but before the speed exceeds the predetermined speed and the temperature exceeds the predetermined temperature), or as soon as these two conditions are measured by the food processing device (during the program). The locking securing means may then be maintained activated during all the subsequent use of the food processing device, and during a rest delay (at least five seconds, and, preferably, at least eight or ten seconds), after complete shutdown of the mobile processing member and/or heating. Thus, opening the lid 20 is impossible only when a risk of overflow exists.

[00086] In other words, according to this variant, the locking securing means are activated at the start-up or during use only if it is planned or measured to exceed the predetermined speed and the predetermined temperature during the next cycle, and the blocking is maintained for a short time even after the complete shutdown of the food processing device. Provision may be made on the display 44 to inform the user whether opening is possible or not. In other words, locking securing means are conditionally activated.

[00087] Therefore, the food processing device comprises a control unit and means for measuring or acquiring the temperature, and means for measuring or acquiring the speed of the mobile processing member 30.

[00088] The temperature of the heating means, the temperature of the receptacle , or the temperature of the food to be prepared, located in the receptacle 10, may be used. The predetermined temperature may be 50 °C or preferably 60 °C.

[00089] Regarding the speed of the mobile processing member 30, one can choose to consider that it is necessary to activate the locking securing means (if the predetermined temperature is exceeded), as soon as a speed range is chosen or measured (for example, the last stage of several preprogrammed speed stages), or as soon as the speed chosen or measured exceeds a particular value, for example 160 rpm or more preferably 250 rpm.

[00090] Thus, by blocking the lid 20 in the locked position during the rest delay, after shutdown of the stirring and heating of the food, as soon as the speed exceeds the predetermined speed simultaneously with the predetermined temperature being exceeded, the opening is impossible as long as there is a risk of accidental overflow and/or boiling.

[00091] It will be understood that various modifications and/or improvements obvious to the person skilled in the art, may be made to the various embodiments of the invention described in the present specification without departing from the scope of the invention. In particular, reference is made to a male engagement portion of the rod, which engages in a female shape of the lid 20, but one can provide a movable female engagement portion of the rod, which engages with a male guide of the lid 20, or even a rocking device (the blocking member may, in particular be mounted to pivot relative to the receptacle or relative to the housing). It is also possible to provide direct drive of the blocking member by the geared motor, or by means of a transmission.

[00092] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Claims

1. A method for controlling the operation of a food processing device, said food processing device comprising: a housing, a receptacle mounted on the housing and configured to receive food to be prepared, at least one mobile processing member positioned in the receptacle and configured for processing the food received in the receptacle, a stirring motor positioned in the housing and configured to set in motion the mobile processing member, a removable lid giving the receptacle a closed state in which the receptacle is closed by the lid, locking means for the lid on the receptacle, the lid being configured to be displaced when the receptacle is in its closed state between: - an unlocked position on the receptacle, in which the lid is released from the locking means, and - a locked position on the receptacle, in which the lid cooperates with the locking means, preferably heating means configured to provide cooking heat to the food received in the receptacle, locking securing means of the lid in the locked position, comprising: at least one movable blocking member between a first position in which the movement of the lid from the locked position to the unlocked position is authorized, and a second position in which the blocking member impedes the movement of the lid from the locked position to the unlocked position, a geared motor configured to act on the blocking member so as to allow it to move between its first position and its second position, the control method including the steps of: estimating a parameter representative of a torque supplied by the geared motor during a control of the geared motor, comparing the estimate of said parameter with a predetermined threshold (Si), and prohibiting the operation of the stirring motor and/or the heating means as long as the estimate of said parameter during a control of the locking securing means remains below the predetermined threshold (S1) in a time interval between a predetermined minimum displacement time (Tm) and a predetermined maximum displacement time (TM), counted from the generation of a control signal from the geared motor.

2. The control method according to claim 1, in which the operation of the stirring motor and/or the heating means is authorized if, during a control of the locking securing means, the estimate of the parameter is greater than the predetermined threshold (S1) at an instant between an intermediate time (Ti) and the predetermined maximum displacement time (TM), the intermediate time (Ti) being between the predetermined minimum displacement time (Tm) and the predetermined maximum displacement time (TM).

3. The control method according to claim 2, in which the operation of the stirring motor and/or of the heating means is authorized if, during a control of the locking securing means, the estimate of the parameter is greater than the predetermined threshold (S1) and if a variation of said parameter as a function of time is greater than a predetermined slope, at an instant between the predetermined minimum displacement time (Tm) and the intermediate time (Ti).

4. The control method according to one of claims 1 to 3, in which the parameter estimation is not carried out or taken into account before a predetermined previous time (Tp), such as 100 ms, counted from the generation of a geared motor control signal.

5. The control method according to claim 4, in which if, during a control of the locking securing means, the parameter estimate is greater than a second predetermined threshold (S2), less than or equal to the predetermined threshold (S1), at an instant between the predetermined previous time (Tp) and the predetermined minimum displacement time (Tm), counted from the generation of a control signal from the geared motor, then a blocking counter is incremented by a value of 1.

6. The control method according to claim 5, further comprising a step consisting in sending the user blocking information if the blocking counter is incremented.

7. The control method according to one of claims 5 or 6, in which the operation of the stirring motor and/or the heating means is prohibited if, during a control of the locking securing means, the estimate of said parameter: is greater than the second predetermined threshold (S2) at an instant between the previous time (Tp) and the minimum displacement time (Tm), remains below the predetermined threshold (S1) throughout the control of the locking securing means.

8. The control method according to one of claims 5 to 7, comprising a step of automatically controlling a change of rotational direction of the geared motor, simultaneously or after the step of incrementing the blocking counter.

9. The control method according to one of claims 5 to 8, in which the locking securing means of the lid are considered to be in a blocked state if the blocking counter exceeds the value of 3.

10. The control method according to one of claims 5 to 9, in which the locking securing means of the lid are considered to be in a normal operating state if the blocking counter is not incremented following a subsequent control, the method then comprising a step of resetting the blocking counter to zero.

11. The control method according to one of claims 1 to 10, in which the parameter representative of the torque supplied by the geared motor is an electric current consumed by the geared motor.

12. The control method according to claims 1 to 11, in which the control signal of the geared motor (51) is a direct current with a voltage that is sometimes positive or sometimes negative depending on the rotational direction to be imparted to the geared motor.

13. The control method according to claim 12, in which the estimate of the current consumed by the geared motor is obtained by calculating an average value resulting from a sampling of values of the geared motor supply current during a geared motor control phase.

14. The control method according to claim 13, in which the sampling frequency is 500 Hz.

15. A food processing device including: - a housing a receptacle mounted on the housing and configured to receive food to be prepared, at least one mobile processing member positioned in the receptacle and configured for processing the food received in the receptacle, a stirring motor positioned in the housing and configured to set in motion the mobile processing member, a removable lid giving the receptacle a closed state in which the receptacle is closed bv the lid.

locking means for the lid on the receptacle, the lid being configured to be displaced when the receptacle is in its closed state between: - an unlocked position on the receptacle, in which the lid is released from the locking means, and - a locked position on the receptacle, in which the lid cooperates with the locking means, the food processing device further comprising: preferably heating means configured to provide cooking heat to the food received in the receptacle, locking securing means of the lid in the locked position, comprising: at least one blocking member, such as a rod comprising a blocking portion, movable between a first position in which the movement of the lid from the locked position to the unlocked position is authorized, and a second position in which the blocking portion impedes the movement of the lid from the locked position to the unlocked position, a geared motor coupled to a control arm configured to move the blocking member between the first position and the second position, means for controlling the operation of the lid locking securing means, control means of the geared motor configured to achieve either locking securing by bringing the blocking member to its second position, or removing the locking securing by bringing the blocking member to its first position, the means of control being configured for: estimating a parameter representative of a torque supplied by the geared motor during a control of the geared motor by the control means, comparing the estimate of said parameter representative of the torque supplied with a predetermined threshold (Si), and prohibiting the operation of the stirring motor and/or the heating means as long as the estimate of said parameter during a control of the geared motor remains below the predetermined threshold (S1) in a time interval between a predetermined minimum displacement time (Tm) and a predetermined maximum displacement time (TM), counted from the generation of a control signal from the geared motor.

16. The food processing device according to claim 15, in which the housing comprises: a first stop configured to cooperate with a first element integral with the control arm so as to define the first position of the blocking member, a second stop configured to cooperate with a second element integral with the control arm so as to define the second position of the blocking member.