WO2017108096A1

WO2017108096A1 - A dishwasher and a method for the detection of the load in a rack of such dishwasher

Info

Publication number: WO2017108096A1
Application number: PCT/EP2015/080970
Authority: WO
Inventors: Hasret GURSOY; Ahmet ALDAG; Serkan Yalcin; Alper BASARAN
Original assignee: Arcelik Anonim Sirketi
Priority date: 2015-12-22
Filing date: 2015-12-22
Publication date: 2017-06-29

Abstract

The present invention relates to a dishwasher comprising a tub (1) delimiting a washing chamber (2) and at least one rack (3) placeable in the washing chamber (2) and aimed to accommodate dishes to be cleaned, whereby a motor (4) is mounted on the tub (1) and has a camshaft, which protrudes into the washing chamber (2) for acting on the rack (3). It is an object of the present invention also to provide a method for the detection of the load in a rack of the dishwasher.

Description

A DISHWASHER AND A METHOD FOR THE DETECTION OF THE LOAD IN A RACK OF SUCH DISHWASHER

The present invention relates to a dishwasher, in particular to a domestic dishwasher, having improved washing performances and to a method for the detection of the load in a rack of such dishwasher.

As it is known, the washing efficiency of a dishwasher depends on the correct selection of the cleaning program, according to the amount of dishes loaded in the wash tub of the dishwasher, i.e. on the racks placed in the tub, and according to the amount of dirt of such dishes.

It often happens, however, that the cleaning program selected by the user is not appropriate for the amount of dishes loaded in the tub and/or for the amount of dirt, resulting either in a poor cleaning performance of the dishwasher or in an unnecessary consumption of an excessive amount of water and of energy.

In order to overcome such problem, in the recent years various dishwashers have been provided which are designed to automatically estimate the amount of dishes loaded in the wash tub of the dishwasher and/or the amount of dirt of such dishes.

An example of such a dishwasher is disclosed in the European patent application n. EP 1530942. The dishwasher therein described comprises a programming device and a sensor of electric field intensity, which is connected to an electrode located inside the tub and to the programming device. The sensor is able to detect changes in the electric field around the electrode and to issue accordingly a signal to the programming device for setting the right cleaning program required by the items loaded in the wash tub.

The electrode located inside the tub of the dishwasher can however be damaged during the loading and unloading operations of the racks into/from the tub, losing its sensing capability.

A further example of such a dishwasher and of a method for the detection of the load in a rack of the dishwasher is disclosed in the international patent application n. WO2013167543. The dishwasher therein described comprises a vibration sensor for detecting vibration generated during the operation of the dishawasher. The amount and the distribution of the load within the tub are estimated by comparing the vibration generated during a preset period of time of operation with the level of vibrations generated during the operation of the dishwasher for a plurality of different known load distributions. This dishwasher, however, can only adapt the already started cleaning program to the dish load estimated, since in order to assess the amount and the distribution of the dish load within the tub the operation of the dishwasher for a preset period of time is required. Therefore the consumption of water and energy could be higher or lower than the necessary at least during the first phases of the cleaning program.

An objective of the present invention is to provide a dishwasher having improved washing performances and a method for the detection of the load in a rack of such dishwasher which allows to optimize the consumption of water and energy according to the effective dish load.

This objective has been achieved by the dishwasher as defined in claim 1, and by the method as defined in claim 10. Further achievements have been attained by the subject-matters respectively defined in the dependent claims.

The dishwasher of the present invention comprises at least one motor provided with a camshaft associated to one of the racks sustaining the dish to be cleaned within the tub. The operation of the motor, with the camshaft that while rotating raises and lowers the rack on which it acts, allows to estimate the weight of the rack, depending on the amount of current drawn by the motor for its operation.

In an embodiment, the motor is mounted on one of the lateral walls of the tub and, more in detail, it is preferably placed below the sliding guide of the rack mounted in such wall for acting on it.

According to a further embodiment the dishwasher comprises a control unit which is programmed for activating and deactivating the motor, for monitoring the current drawn by the motor for raising and lowering the rack by means of its camshaft and for estimating the weight of the dishes placed on the rack based on the current drawn by the motor.

In a version of this embodiment, the control unit is programmed to simply determine, on the basis of the current drawn by the motor, if the rack is empty or loaded.

In another embodiment, the control unit is programmed to emit an output signal according to the estimated weight of the dishes for helping the user to select the most appropriate cleaning program, which can be a warning signal to warn the user in case he/she is selecting a program which is not appropriate for the estimated load or an information signal for helping the user to make an appropriate program selection.

According to an embodiment, the dishwasher further comprises input means connected to the control unit for allowing the user to input information on the kind of dishes being placed on the rack.

In an embodiment, the control unit is programmed to activate the motor at least for an interval of time during the drying phase of the cleaning program, in order to favor to drip off water from the dishes on the rack.

The method for the detection of the load in a rack of a dishwasher according to the invention comprises: activating the motor so that its camshaft, by rotating, raises and lowers the rack on which it acts; detecting the value of the current drawn by the motor; comparing the detected value of the current with at least one reference value memorized in the control unit; estimating, by means of the control unit, the weight of the dishes placed on the rack based on the comparison between the detected value of current and the reference value; and providing, by means of the control unit, an output signal according to the estimated weight of the dishes for helping the user to select the most appropriate cleaning program.

In a version of the method, the reference value of the current is the value of the current drawn by the motor when the rack on which it acts is empty and it is preferably measured and preset by the producer.

In a further version of the method, during the step of estimating the weight of the dishes placed on the rack, the control unit estimates if the rack is empty or loaded with dishes.

According to a version of the method, the control unit is programmed to associate to the estimated weight of the dishes placed on the rack one or more appropriate cleaning programs, based on preset cleaning programs that are memorized in the control unit associated to the different possible load conditions of the dishwasher.

According to a further version, the control unit is programmed to compare the cleaning program selected by the user with the preset appropriate cleaning programs and the output signal provided by the control unit is a warning signal which is provided when the control unit determines that the cleaning program selected by the user differs from the at least one appropriate cleaning program.

In an embodiment, the output signal provided by the control unit is an information signal aimed to indicate to the user the appropriate cleaning program or programs.

Additional advantages of the dishwasher and of the method of the present invention will become apparent with the detailed description of the embodiments with reference to the accompanying drawings in which:

Figure 1 – is a first perspective view of a wash tub of a dishwasher according to the invention with a rack placed into it.

Figure 2 – is a second perspective view of the wash tub of Figure 1 wherein the rack has been removed.

Figure 3 – is a side view of the wash tub of Figure 1, wherein some parts of the tub have been removed in order to show the interior of it.

Figure 4 – is a sectional view of the wash tub of Figure 1 taken along line IV-IV of Figure 3.

The reference signs appearing on the drawings relate to the following technical features.

Tub
Washing chamber
Rack
Motor
Camshaft
Lateral walls
Rear wall
Frontal opening
Sliding guides

The dishwasher comprises a tub 1 delimiting a washing chamber 2 and one or more racks 3 placeable in the washing chamber 2 and aimed to accommodate dishes, i.e. more in detail dishes, kitchenware, tableware, crockery etc., to be cleaned. In particular, according to a preferred embodiment, the dishwasher 1 comprises two racks 3 which are extendably disposed into the washing chamber 2 one above the other, although in the attached Figures 1, 3 and 4 only the upper rack 3 is illustrated.

According to the invention, the dishwasher further comprises a motor 4 mounted on the tub 1 and having a camshaft 5 protruding in the washing chamber 2. The camshaft 5 is positioned in the washing chamber 2 so that it can act on the rack 3 when the latter is placed in the washing chamber 2. The motor 4 in the dishwasher according to the invention, by the rotation of its camshaft 5 and by the detection of the current requested for the camshaft 5 to rotate while raising the rack 3, allows to estimate the weight, and hence the effective load, of the associated rack 3, so that the most appropriate cleaning program can be accordingly selected either automatically by the dishwasher or by the user assisted by the dishwasher as better specified hereafter. Therefore the dishwasher according to the invention, by being provided with a motor 4 having a camshaft 5, allows to detect the load of dishes to be cleaned placed in the associated rack 3 in a reliable, easy and cost-effective manner.

In an embodiment, the motor 4 is a 12V DC motor, which is suitable for the purpose of the invention and economic, so that it does not entail a significant increase in the production costs of the dishwasher.

The tub 1 comprises two lateral walls 6 and a rear wall 7, which delimit together with a bottom and a top wall the washing chamber 2, and it further comprises a frontal opening 8, opposite to the rear wall 7, through which the rack 3, or the racks 3, is introduced and removed into/from the washing chamber 2.

According to the embodiment illustrated in the attached figures, the motor 4 is mounted on one of the lateral walls 6 of the tub 1. This location of the motor 4 allows its camshaft 5 to easily reach the rack 3 and at the same time it allows the motor 4 to be easily reachable for maintenance interventions.

In an embodiment, the dishwasher comprises only one motor 4 mounted on one of the lateral walls 6 of the tub 1 in order to act on the associated rack 3, since it is sufficient for estimating the weight of the rack 3. However two motors 4 associated to the same rack 3, one mounted on each of the lateral walls 6, can be provided without departing from the scope of the present invention.

In a further embodiment, only one of the racks 3, and preferably only the upper rack 3, of the dishwasher is associated to a motor 4 for the estimation of its weight, so that the presence of a full load, with items to be cleaned placed on both the racks, or only of half load, with items to be cleaned placed only on the rack not associated to the motor 4, can be estimated.

According to an embodiment, the rack 3 to which the motor 4 is associated comprises a couple of sliding guides 9, each slidably mounted on a corresponding lateral wall 6 of the tub 1 for allowing an easy and smooth introduction and removal of the rack 3 into/from the washing chamber 2 and the camshaft 5 of the motor 4 is placed in the washing chamber 2 below one of the sliding guides 9 for acting on it. This allows the camshaft 5 to protrude of a minimum extent into the washing chamber 2 and it further ensures that the rack 3 rests securely on the camshaft 5 and remained engaged to the camshaft 5 during the rotation of the latter.

In a preferred embodiment, the dishwasher further comprises a control unit programmed to estimate the weight of the dishes placed on the rack 3 based on the current drawn by the motor 4 for instance from the network.

In particular the control unit is advantageously programmed to compare the measured value of the current drawn by the motor 4 with one or more reference values of current drawn by the motor 4 in known conditions of load, to estimate consequently the actual load status of the rack 3.

In a preferred embodiment, the control unit is programmed to determine, on the basis of the current drawn by the motor 4, simply if the rack 3 is empty or loaded. To this aim, the control unit is programmed to compare the measured value of the current drawn by the motor 4 in the operation conditions of interest with the value of the current drawn by the motor 4 when the rack 3 is empty. This allows for instance to detect the presence or absence of dishes on the rack 3 and consequently to automatically establish, by means of the control unit, which cleaning program would be appropriate to be performed between a cleaning program for half load and a cleaning program for full load.

According to an embodiment, the control unit is programmed to generate and emit an output signal depending on the estimated weight of the dishes for helping the user to select the most appropriate cleaning program.

More in detail, the output signal generated by the control unit, in a version of this embodiment, is sent to a display provided on the dishwasher in order to provide a visual information signal to the user, such as for instance a visual indication of the load status of the dishwasher, i.e. full load or half load, or a visual indication of the suggested cleaning program or cleaning programs, which are preset by the producer and memorized in the control unit depending on the estimated load of dishes.

In a further version of this embodiment, the output signal is a warning signal, which is emitted by the control unit depending on the estimated weight of the dishes and on the cleaning program selected by the user, if the control unit determines that the cleaning program selected by the user is inappropriate for the estimated weight of dishes.

The warning signal is for instance an acoustic signal or a visual signal, such as an intermittent light aimed to catch the attention of the user, or both.

More in detail, according to this embodiment, one or more appropriate cleaning programs are preset by the producer and memorized in the control unit for the different possible load conditions of the rack 3 and the control unit is programmed to verify if the cleaning program selected by the user is among the preset appropriate cleaning programs and to emit a warning signal if this condition is not verified..

According to an embodiment, the dishwasher further comprises input means, such as for instance a button, a knob or a selectable menu on a display, connected to the control unit for allowing the user to input information on the kind of dishes being placed on the rack 3. More in detail the input means are designed to allow the user to select for instance among light weight or heavy weight items, or to select more specifically the material of which the items are mainly made, such as metal, glass, plastic or ceramic. Thanks to the presence of the input means the control unit can be programmed to determine the effective load of the rack, by estimating the weight of the rack 3 and depending on the kind of items that have been placed on the rack 3, i.e. light weight items, such as plastic items, or heavy weight items, such as metal and ceramic items, which information is provided by the user. Consequently the dishwasher can automatically estimate the most efficient cleaning program.

In an embodiment of the dishwasher according to the invention, the control unit is programmed to activate the motor 4 at least for an interval of time during the drying phase of the cleaning program and preferably at the beginning of it. The rotation of the camshaft 5 of the motor 4, in fact, allows to gently shake the rack 3, and consequently to drip off water from the items in the rack 3, thus favoring an efficient drying of the items.

It is an object of the present invention also a method for the detection of the load in a rack of a dishwasher.

The method comprises firstly activating the motor 4 so that its camshaft 5, by rotating, raises and lowers at least partially the rack 3 on which it acts. In particular the motor 4 is preferably activated by the control unit before starting the cleaning program or at the beginning of the cleaning program, so that possible waist of energy and water due to a wrong selection of the cleaning program can be avoided.

The method hence comprises detecting the value of the current drawn by the motor 4 and comparing, by means of the control unit, the detected value of the current with one or more reference values of current measured for known load conditions of the rack 3 and memorized in the control unit.

By means of the control unit, the weight of the dishes placed on the rack 3 is then estimated, based on the comparison between the detected value of current and the reference value of current.

The method comprises then providing, by means of the control unit, an output signal according to the estimated weight of the dishes for helping the user to select the most appropriate cleaning program.

In a version of the method, the reference value of the current is the value of the current drawn by the motor 4 when the rack 3 on which it acts is empty. Preferably such reference value of current is determined by the producer and it is memorized in the control unit.

In a further version of the motor, by the step of estimating the weight of the dishes placed on the rack 3 the control unit estimates if the rack 3 is empty or loaded with dishes, in particular by comparing the measured current drawn by the motor 4 with the known reference value of current correspondent to the rack 3 being empty.

According to a version of the method, the control unit is programmed to associate to the estimated weight of the dishes placed on the rack 3 one or more appropriate cleaning programs, which are preset by the producer and memorized in the control unit depending on the estimated load of dishes, as previously specified. For instance if the control unit is programmed just to detect if the rack 3 is loaded or not, the appropriate cleaning programs are respectively programs for a full load condition or for a half load condition of the dishwasher.

In a further version of the method, the control unit is programmed to compare the cleaning program selected by the user with the appropriate cleaning program or programs associated to the estimated weight of the dishes and memorized in the control unit. The output signal provided by the control unit is in this case a warning signal which is provided when the control unit determines that the cleaning program selected by the user differs from the appropriate cleaning program or programs memorized in the control unit for the estimated weight.

In another version of the method, the output signal provided by the control unit is an information signal aimed to indicate to the user the appropriate cleaning program or programs in order to help the user to select correctly the cleaning program based on the effective load condition of the dishwasher.

With the present invention, the dishwasher has been enabled to perform an efficient cleaning of the dishes in the tub, while avoiding possible waist of water and energy.

Claims

A dishwasher comprising a tub (1) delimiting a washing chamber (2) and at least one rack (3) placeable in the washing chamber (2) and aimed to accommodate dishes to be cleaned,

characterized in that the dishwasher further comprises a motor (4) mounted on the tub (1) and having a camshaft (5) which protrudes into the washing chamber (2) for acting on the rack (3).
The dishwasher according to claim 1, characterized in that the camshaft (5) is designed to raise and lower at least partially the rack (3) in the washing chamber (2) by rotating when the motor (4) is activated.
The dishwasher according to claim 1 or 2, characterized in that the tub (1) comprises two lateral walls (6), a rear wall (7) and a frontal opening (8), opposite to the rear wall (7), through which the at least one rack (3) is introduced and removed into/from the washing chamber (2), the motor (4) being mounted on one of the lateral walls (6) of the tub (1).
The dishwasher according to claim 3, characterized in that the at least one rack (3) comprises a couple of sliding guides (9) mounted on the lateral walls (6) of the tub (1) for allowing its introduction and removal into/from the washing chamber (2) and the camshaft (5) of the motor (4) is placed in the washing chamber (2) below one of the sliding guides (9) for acting on it.
The dishwasher according to any of the claims 2-4, characterized in that it further comprises a control unit programmed to estimate the weight of the dishes placed on the rack (3) based on the current drawn by the motor (4) for the camshaft (5) to raise and lower at least partially the rack (3).
The dishwasher according to claim 5, characterized in that the control unit is programmed to determine, on the basis of the current drawn by the motor (4), if the rack (3) is empty or loaded.
The dishwasher according to claim 5 or 6, characterized in that the control unit is programmed to emit an output signal according to the estimated weight of the dishes for helping the user to select the most appropriate cleaning program.
The dishwasher according to claim 7, characterized in that the output signal is a warning signal, which is emitted by the control unit depending on the estimated weight of the dishes and on the cleaning program selected by the user, if the control unit determines that the cleaning program selected by the user is inappropriate for the estimated weight of dishes.
The dishwasher according to any of the claims 5 to 8, characterized in that it further comprises input means connected to the control unit for allowing the user to input information on the kind of dishes being placed on the rack (3).
The dishwasher according to any of the claims 5 to 9, characterized in that the control unit is programmed to activate the motor (4) at least for an interval of time during the drying phase of the cleaning program.
A method for the detection of the load in a rack of a dishwasher according to any of the previous claims, comprising:

- activating the motor (4) so that its camshaft (5), by rotating, raises and lowers at least partially the rack (3) on which it acts;

- detecting the value of the current drawn by the motor (4);

- comparing the detected value of the current with at least one reference value memorized in the control unit;

- estimating, by means of the control unit, the weight of the dishes placed on the rack (3) based on the comparison between the detected value of current and the reference value;

- providing, by means of the control unit, an output signal according to the estimated weight of the dishes for helping the user to select the most appropriate cleaning program.
A method according to claim 11, wherein the at least one reference value of the current is the value of the current drawn by the motor (4) when the rack (3) on which it acts is empty.
A method according to claim 12, wherein by the step of estimating the weight of the dishes placed on the rack (3) the control unit estimates if the rack (3) is empty or loaded with dishes.
A method according to any of the claims 11 to 13, wherein the control unit is programmed to associate to the estimated weight of the dishes placed on the rack (3) at least one appropriate cleaning program.
A method according to any of the claim 14, wherein the control unit is programmed to compare the cleaning program selected by the user with the at least one appropriate cleaning program and the output signal provided by the control unit is a warning signal which is provided when the control unit determines that the cleaning program selected by the user differs from the at least one appropriate cleaning program.