EP2415919A1

EP2415919A1 - Operating method of a laundry washing machine and laundry washing machine implementing such method

Info

Publication number: EP2415919A1
Application number: EP10172145A
Authority: EP
Inventors: Joseph Migeot; Andrea Mazzon; Mustapha Taffahi
Original assignee: Electrolux Home Products Corp NV
Current assignee: Electrolux Home Products Corp NV
Priority date: 2010-08-06
Filing date: 2010-08-06
Publication date: 2012-02-08
Anticipated expiration: 2030-08-06
Also published as: EP2415919B1

Abstract

Operating method of a laundry washing machine (1) comprising an outer casing (2), a rotatable drum (6) structured for housing the laundry to be washed and which is housed in axially rotating manner inside the casing (2) for rotating about its longitudinal axis (L), motor means (7) structured for driving into rotation the rotatable drum (6) about its longitudinal axis (L), and a control unit (18) which controls at least said motor means (7); the laundry washing machine operating method comprising the steps of carrying out, in sequence, the washing/rinsing stage and the spin stage of the selected washing cycle, and additionally the step of selecting, among a plurality of spin-launch algorithms stored inside a memory module and each of which is univocally associated to a specific weight-range of the laundry loaded inside the rotatable drum (6), the spin-launch algorithm univocally associated to the weight-range encompassing the weight of the laundry currently loaded inside the rotatable drum (6); and the step of carrying out the spin stage of the selected washing cycle according to the currently selected spin-launch algorithm.

Description

The present invention relates to an operating method of a laundry washing machine and to a laundry washing machine implementing such method.
More specifically, the present invention relates to an operating method of a rotary-drum laundry washing machine and to a rotary-drum laundry washing machine implementing such method.
It is underlined that in the present application the expression "laundry washing machine" may indicate as well a "simple" washing machine, i.e. a washing machine which is adapted only for washing the laundry, and also a washer/drier, i.e. a laundry machine which may wash and also dry the laundry.
The following description refers purely by way of example to a front-loading, rotary-drum laundry washing machine without this implying any loss of generality (in fact the invention can be as well applied to a top-loading laundry washing machine).
As is known, currently marketed front-loading laundry washing machines generally comprise:

a substantially parallelepiped-shaped outer boxlike casing structured for resting on the floor;
a substantially bell-shaped washing tub which is suspended in floating manner inside the casing by means of a number of coil springs and shock-absorbers, directly facing a laundry loading and unloading through opening realized in the front face of the casing;
a substantially cylindrical elastically-deformable bellows, which connects the front opening of the washing tub to the laundry loading and unloading opening formed in the front face of the casing;

a porthole door which is hinged to the front face of the casing to rotate to and from a closing position in which the door closes the laundry loading and unloading through opening in the front face of the casing to seal the washing tub;
a substantially cylindrical, bell-shaped rotatable drum structured for housing the laundry to be washed, and which is housed inside the washing tub in axially rotating manner about its substantially horizontally-oriented longitudinal axis; and finally
an electrically-powered motor assembly which is structured for driving into rotation the rotatable drum about its longitudinal axis inside the washing tub.

As is known, when loaded inside the drum of a front-loading washing machine, the laundry accumulates on the bottom of the cylindrical lateral wall of the rotatable drum, and is subsequently distributed dynamically and randomly over the whole cylindrical lateral wall of the rotatable drum during all the stages of the washing cycle in which the drum rotates about its longitudinal axis, with the exception of the spin stage, in which the extremely fast rotating speed of the rotatable drum stabilizes and freezes distribution of the laundry on the lateral wall of the drum.
Obviously, during the spin stage the laundry is usually not evenly distributed over the whole cylindrical lateral wall of the rotatable drum, thus the electronic control unit of the washing machine is generally programmed to determine, at beginning of the spin stage, the unbalanced component of the weight of the laundry stored inside the rotatable drum, and to command the motor assembly so as to carry out a predetermined control strategy for the rotating speed of the drum; this control strategy attempts to evenly distribute the laundry inside the rotatable drum to minimize the unbalanced component of the weight of the laundry inside the drum, so as to minimize mechanical vibration transmitted to the casing and consequently reduce the noise level at spin stage.
In fact, according to kinematics physics, the weight distribution of the laundry stored inside the rotatable drum when the distribution of this laundry on the lateral wall of the drum is frozen, due to the high rotating speed, can be schematically represented as a combination of a balanced mass and an unbalanced mass, both located inside the rotatable drum. The balanced mass is evenly distributed on the cylindrical lateral wall of the drum and does not cause mechanical vibrations; whereas the unbalanced mass is concentrated in a specific point on the cylindrical lateral wall of the rotatable drum, and causes all mechanical vibrations of the rotatable drum and washing tub.
At beginning of the spin stage, a "spin-launch stage" is provided, i.e. a stage in which the electronic control unit of the washing machine determines firstly the weight of the unbalanced mass (i.e. the unbalanced component of the weight of the laundry inside the drum), and afterward, if such weight exceeds a given threshold value, it commands the motor assembly so that the angular speed of the rotatable drum follows a predetermined speed-time weight-reallocating path which is specifically designed to better distribute the laundry on the cylindrical lateral wall of the rotatable drum. This speed-time weight-reallocating path comprises, for example, stopping the rotation of the drum for a certain time interval and/or reversing the rotation of the drum and/or reducing the rotating speed, etc., so that the laundry may detach from the lateral wall of the drum and change its spatial distribution.
After the speed-time weight-reallocating path is completed, the electronic control unit of the washing machine checks again the unbalanced component of the weight of the laundry stored inside the rotatable drum (i.e. determines again the weight of the unbalanced mass) and, if the unbalanced component of the laundry weight still exceeds said threshold value, it may decide to repeat again the speed-time weight-reallocating path, or to abort the spin stage, or to perform the spin stage at a maximum angular speed which is lower than that of the nominal angular speed preset for the selected washing cycle.
The profile of the speed-time weight-reallocating path used for reallocating the laundry inside the drum, the maximum number of attempts for optimizing the distribution of the laundry on the cylindrical lateral wall of the drum, the physical parameters and thresholds values taken into consideration in the decision, and the decision-making logic upon which the control unit decides to abort or reduce the spin stage, depend on the specific "spin-launch algorithm" stored in the control unit of the laundry washing machine; in other words the spin-launch stage of the spin stage depends on the specific "spin-launch algorithm" stored in the control unit of the laundry washing machine.
Despite the presence of the spin-launch algorithm referred above, experimental tests revealed that the spin stage of a relatively high percentage of the washing cycles is aborted (or sometimes performed at a reduced maximum angular speed) because very often the spin-launch algorithm isn't able to effectively reduce the weight of the unbalanced mass, thus causing a relevant extension of the laundry drying time.
Aim of the present invention is to provide a rotary-drum laundry washing machine operating method which can significantly improve the percentage of washing cycles which ends with a standard spin cycle (i.e. a spin cycle which is performed at the nominal angular speed which is preset for the selected washing cycle).
In compliance with the above aims, according to the present invention there is provided a laundry washing machine operating method as specified in Claim 1 and preferably, though not necessarily, in any one of the dependent claims.
Moreover, according to the present invention, there is provided a laundry washing machine as specified in Claim 9 and preferably, though not necessarily, in any one of the dependent claims.
A non-limiting embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 shows a schematic section view of a front-loading, rotary-drum laundry washing machine realized in accordance with the teachings of the present invention; whereas
Figures 2 and 3 show respective speed-time charts of the angular speed of the rotatable drum during the spin stage of a same washing cycle implemented by the Figure 1 laundry washing machine.

With reference to Figure 1, number 1 indicates as a whole a laundry washing machine which comprises: a preferably, though not necessarily, parallelepiped-shaped outer boxlike casing 2; a substantially cylindrical hollow washing tub 3 suspended in floating manner inside casing 2 in known manner via a suspension system preferably, though not necessarily, comprising a number of coil springs 4 (only one shown in Figure 1) connecting the upper portion of washing tub 3 to the top of casing 2, and one or more vibration dampers 5 (only one shown in Figure 1) connecting the lower portion of washing tub 3 to the bottom of casing 2; a substantially cylindrical hollow rotatable drum 6 structured for housing the laundry to be washed, and which is housed in axially rotating manner inside the washing tub 3 for rotating about its longitudinal axis L; and an electrically-powered motor assembly 7 which is structured for driving into rotation, on command, the rotatable drum 6 about its longitudinal axis L inside the washing tub 3.
In the example shown washing machine 1 (in the present application the expression "washing machine" can indicate as well a "simple" washing machine and a washer/drier) is preferably, though not necessarily, a front-loading laundry washing machine (but clearly the invention can be applied as well to a top-loading washing machine), thus washing tub 3 is substantially bell-shaped and it is suspended inside casing 2 substantially horizontally, with its front opening directly faced to a laundry loading and unloading through opening 2a formed in the front face of casing 2.
Moreover, the front-loading laundry washing machine 1 additionally comprises a cylindrical elastically-deformable bellows 8 which connects the front opening of washing tub 3 to the laundry loading and unloading opening 2a formed in the front face of casing 2; and a porthole door 9 which is hinged to the front face of casing 2 to rotate about a preferably, though non necessarily, vertically-oriented reference axis to and from a closing position in which the porthole door 9 rests on the front face of casing 2 for closing the laundry loading and unloading opening 2a and watertight seal the washing tub 3.
Rotatable drum 6, in turn, is substantially bell-shaped and it is preferably, though not necessarily, housed inside washing tub 3 so that its longitudinal axis L is oriented substantially horizontally and approximately coincides with the longitudinal axis of the washing tub 3.
With reference to Figure 1, the laundry washing machine 1 also preferably, but not necessarily comprises: a fresh water supply circuit 10 which is structured for supplying, on command, a given amount of tap water into the washing tub 3; a washing-water recirculating and/or draining circuit 11 which is structured for sucking, on command, the washing water from the bottom of washing tub 3 and feeding said water back inside rotatable drum 6 during the washing and rinsing phases of the washing cycle, or alternatively draining the water accumulated on the bottom of washing tub 3 directly into a waste-water exhaust duct (non shown) located outside of casing 2; an electrically operated water heater 12, for example a resistor, which is located on the bottom of washing tub 3, preferably, thought not necessarily, into an outwards-projecting basin-shaped seat realized on the bottom of washing tub 3, and is structured for rapidly heating the washing water accumulated on the bottom of washing tub 3; and a detergent dispenser 13 which is structured for supplying into the washing tub 3 the detergents and/or softeners to be used in the washing cycle.
In the example shown detergent dispenser 13 preferably, though not necessarily, consists of a substantially parallelepiped-shaped container or receptacle 13 which is fixed to the front wall of casing 2 immediately above washing tub 3, so as to be directly accessible from an opening realized on the front wall of the casing 2, and it is structured for housing in manually-extractable manner a detergent drawer (not shown) which, in turn, is provided with one or more compartments dimensioned for storing a given amount of detergent and/or softener to be used in the washing cycle.
The bottom of the parallelepiped-shaped container or receptacle 13 directly communicates with the inside of washing tub 3, and the freshwater supply circuit 10 is structured for spilling, on command, the fresh/tap water of the water mains directly into the detergent drawer fitted into the drawer container or receptacle 13, so as to flush into washing tub 3 the detergents and/or softeners previously left into the detergent drawer.
The freshwater supply circuit 10, the washing-water recirculating and/or draining circuit 11, the water heater 12 and the detergent dispenser 13, are commonly known parts in the laundry washing machines technical field, and therefore won't be described in further details.
With reference to figure 1, the motor assembly 7 is instead firmly attached to the washing tub 3, outside the latter, and preferably, though not necessarily, comprises: a first pulley 14 rigidly fitted to the end of the supporting shaft 6a of rotatable drum 6, which protrudes from the back of the washing tub 3 coaxial to the drum longitudinal axis L; an electric motor 15 which is rigidly fixed to the bottom of washing tub 3, outside the latter, with its driving shaft substantially parallel to the supporting shaft 6a of rotatable drum 6; a second pulley 16 which is rigidly fitted to the driving shaft of electric motor 15, substantially coplanar to pulley 14; and finally a driving belt 17 which is wound around the pulleys 14 and 16 to mechanically connect motor 15 to rotatable drum 6.
In a more sophisticated embodiment of the laundry washing machine 1, the motor assembly 7 may consist only in an electric motor which is mechanically coupled directly to the end of the drum supporting shaft 6a which protrudes from the back of washing tub 3.
With reference to Figure 1, laundry washing machine 1 finally comprises, inside casing 2, an electronic control unit 18 which preferably controls the electric motor 15 of motor assembly 7, the solenoid valve/s of the fresh water supply circuit 10, the electric pump/s and/or solenoid valve/s of the washing water recirculating and/or draining circuit 11, and the water heater 12.
Washing machine 1 preferably comprises also a laundry weight detecting device 19 which is able to measure instant by instant the weight of washing tub 3 with everything located therein, and to communicate the weight value to the control unit 18.
Advantageously, control unit 18 controls the electric motor 15 of motor assembly 7, the solenoid valve/s of the fresh water supply circuit 10, the electric pump/s and/or solenoid valve/s of the washing water recirculating and draining circuit 11, and the water heater 12, on the basis of the washing cycle to be performed by the washing machine, and which is preferably manually selectable by the user via a control panel 20 located preferably, though not necessarily, on the front face of casing 2, immediately above the laundry loading and unloading opening 2a.
Laundry weight detecting device 19, in turn, directly measures the current weight of washing tub 3 and allows control unit 18 to calculate the weight of the laundry currently loaded inside rotatable drum 6 as a difference between the currently measured weight of the loaded washing tub 3 and the weight of the washing tub 3 in empty condition.
In the example shown the laundry weight detecting device 19 preferably, though not necessarily, consists in a measuring device 19 structured for measuring instant by instant the length of one or more of the coil springs 4 connecting the upper portion of washing tub 3 to the top of casing 2. Extension of the coil springs 4 at beginning of the washing cycle in fact depends on the weight of the laundry loaded into the washing tub 6.
In a further embodiment of the laundry washing machine 1, control unit 18 may be structured for estimating/calculating the laundry weight on the basis of the laundry material (for example cotton, synthetic or wool) selected by the user (or, in another embodiment, detected by the washing machine by a known detecting procedure,) and of the amount of tap water absorbed by the laundry at a certain phase (e.g. at the beginning) of the washing cycle.
Determination of the amount of tap water absorbed by the laundry (particularly at beginning of the washing cycle) is a well know practice in the laundry washing machines technical field, and therefore wont be described in further details.
In a further embodiment thereof the weight of the laundry may be estimated/calculated from the value of the current absorbed by the motor for rotating the drum; also this solution is a well know practice in the laundry washing machines technical field, and therefore wont be described in further details.
Differently from today's laundry washing machines, the laundry washing machine according to the invention comprises a memory module (e.g. an EPROM, a microchip, etc., preferably, but not necessarily, comprised in the control unit 18) in which there is stored a plurality of different spin-launch algorithms (adapted to control the functioning of the washing machine during the spin-launch stage present at the beginning of the spin stage), each of which is univocally associated to a specific weight-range of the laundry loaded inside the rotatable drum 6, and the laundry washing machine 1 is structured to carry out the spin-launch algorithm univocally associated to the weight-range in which the weight of the laundry currently loaded inside the rotatable drum 6 is comprised.
For example, in the example shown four different spin-launch algorithms are preferably, though not necessarily, stored within the memory module of control unit 18: the first spin-launch algorithm is univocally associated to a laundry weight (LW) ranging between 0 and 2 Kilos (i.e. LW > 0 kg and LW < 2 kg); the second spin-launch algorithm is univocally associated to a laundry weight (LW) ranging between 2 and 4 Kilos (i.e. LW ≥ 2 kg and LW < 4 kg); the third spin-launch algorithm is univocally associated to a laundry weight (LW) ranging between 4 and 6 Kilos (i.e. LW ≥ 4 kg and LW < 6 kg); whereas the fourth spin-launch algorithm is univocally associated to a laundry weight (LW) bigger that 6 Kilos (i.e. LW ≥ 6 kg).
Each spin-launch algorithm comprises a specific logic procedure (different from the ones of the other spin-launch algorithms stored in the memory module) according to which the washing machine operates during the spin-launch stage present at the beginning of the spin stage, in order to try to minimize an unbalanced mass present in the rotatable drum 6, so as to allow performing the rest of the spin stage, preferably at a nominal angular speed preset for the selected washing cycle.
Advantageously, two distinct spin-launch algorithms may be different one another for the whole, or only for a certain part of, the logic procedure they apply to control the functioning of the laundry washing machine during the spin-launch stage.
Each spin-launch algorithm stored in the memory module is preferably, though not necessarily, provided with one or more specific speed-time paths of the angular speed of drum, specifically designed to detach the laundry from the cylindrical lateral wall of rotatable drum 6; in other words each spin-launch algorithm stored in the memory module is preferably, though not necessarily, provided with at least one specific procedure according to which the rotation speed of drum is modified in order to detach the laundry from the cylindrical lateral wall of rotatable drum 6. For example in one algorithm the rotation of the drum may be simply stopped in order to detach the laundry, in another algorithm the rotation of the drum may be inverted, in another algorithm the rotation speed may be reduced, in another algorithm the rotation speed may be firstly inverted, than reduced, then inverted again, then increased, etc.
Each spin-launch algorithm stored in the memory module is preferably, though not necessarily, provided with one or more specific speed-time unbalanced-weight detecting path of the angular speed of drum, which is specifically designed to determine the unbalanced component of the weight of the laundry currently loaded inside the rotatable drum 6. In other words, each algorithm is preferably, though not necessarily, provided with at least one specific procedure according to which the unbalanced mass is detected; for example in one algorithm the unbalance mass may be detected at a constant rotation speed of the drum, while in another algorithm the unbalance mass may be detected at a variable rotation speed of the drum.
Each spin-launch algorithm stored in the memory module is preferably, though not necessarily, provided with one or more specific speed-time weight-reallocating paths of the angular speed of drum, which is specifically designed to reallocate the laundry loaded inside the rotatable drum 6; in other words each spin-launch algorithm stored in the memory module is preferably, though not necessarily, provided with at least one specific procedure according to which the rotation speed of drum is modified in order to reallocate the laundry loaded inside the rotatable drum 6. For example in one algorithm the rotation of the drum may be simply stopped in order to reallocate the laundry, in another algorithm the rotation of the drum may be inverted, in another algorithm the rotation speed may be reduced, in another algorithm the rotation speed may be firstly inverted, than reduced, then inverted again, then increased, etc.
Each spin-launch algorithm stored in the memory module is preferably, though not necessarily, provided with a specific decision-making logic for aborting the spin or for reducing the maximum angular speed of the drum during the spin stage if the value of the unbalanced mass has not been enough reduced during the spin-launch stage. The decision-making logic and the speed-time pats are all optimized for a laundry amount having a weight included in the weight-range associated to the spin-launch algorithm.
In other words, each specific algorithm stored in the memory module applies a specific and distinct logic procedure for trying to minimize the unbalance of the load during the spin stage, and/or for deciding if performing or not the spin (or to perform the spin at a reduced speed) depending on the current value of the unbalanced mass; for example one of these algorithms may contain a specific procedure (or sub-algorithm) for determine the unbalanced mass, and another specific procedure (or sub-algorithm) for trying to minimize the unbalance mass, these specific procedures (or sub-algorithms) being alternated according to a logic procedure specific for this algorithm (and different from the one of the other stored algorithms), and reiterated a prefixed number of times if the unbalance mass is not reduced enough.
Therefore two of the algorithms stored in the memory module may differ one another for the type of procedure they use to detect the value of the unbalanced mass, for the path of the rotating speed used for trying to reduce the unbalanced mass, for the sequence and/or the number of times these procedures are applied, for the maximum available value of the unbalanced mass for which the spin starts, etc.; more in general the algorithms stored in the memory module differ one another for the logic procedure according to which they cause the washing machine to operate for trying to minimize the unbalanced mass in order to allow the performance of the spin stage, preferably at a nominal angular speed preset for the selected washing cycle.
It is underlined that a spin-launch algorithm comprises a series of well-defined instructions for completing the task of minimizing the unbalanced mass; these instructions comprise a series of operations (e.g. reversing or stopping the rotation of the rotatable drum, measuring the unbalanced mass, starting the spin at a prefixed speed, etc.) to be performed by the washing machine or not, according to the fact that some conditions are verified or not (e.g. the fact that the measured unbalanced mass, at a certain moment of the spin-launch stage, is lower than a prefixed value, or the fact that a certain number of repetitions of a specific operation has been reached, etc).
As a consequence, with reference for example to Figures 2 and 3, during the spin stage the speed-time curve of the angular speed of rotatable drum 6 may vary considerably depending on the weight of laundry loaded inside the rotatable drum 6 and on the unbalanced component of the laundry weight, even if the washing cycle selected by the user is the same.
For example, Figure 2 discloses a first possible speed-time curve ω1(t) of the angular speed of rotatable drum 6 during the spin stage of a washing cycle in which the laundry load is 5 kilos and the unbalanced component of the laundry weight is 0,5 kilos; whereas Figure 3 discloses a second possible speed-time curve ω2(t) of the angular speed of rotatable drum 6 during the spin stage of an identical washing cycle in which the laundry load is 2 kilos and the unbalanced component of the laundry weight is 0,5 kilos.
It is however underlined that the same spin-launch algorithm applied to different unbalanced mass (or also to the same unbalanced mass, but at different times), even if the overall weight of the loaded laundry is the same, could generate different speed-time curves of the angular speed of the rotatable drum. Moreover it is also possible that different spin-launch algorithms applied to different quantities of loaded laundry could generate similar time-speed curves of the angular speed of the drum.
Operating method of the laundry washing machine 1 comprises the steps of carrying out, in sequence, the washing/rinsing stage and the spin stage of the user-selected washing cycle, and differs from operating method of traditional laundry washing machines in that it also comprises

the step of selecting, among the various spin-launch algorithms stored inside a memory module of the laundry washing machine, the spin-launch algorithm univocally associated to the weight-range in which the weight of the laundry currently loaded inside the rotatable drum 6 is comprised; and
the step of carrying out the spin stage of the washing cycle according to the currently selected spin-launch algorithm.

Selection of the most appropriate spin-launch algorithm may be performed, preferably by the control unit 18, either before or after the washing/rinsing stage of the washing cycle.
Before selection of the most appropriate spin-launch algorithm among the ones stored in the memory module, operating method of the laundry washing machine 1 additionally comprises the step of determining the weigh of the laundry currently loaded inside the rotatable drum 6.
Determination of the weigh of the laundry currently loaded inside rotatable drum 6 may be performed either before or after the washing/rinsing stage of the washing cycle.
In the example shown, the measuring of the current weight of the washing tub 3 is preferably, though not necessarily, performed by the laundry weight detecting device 19, for example immediately before the washing/ rinsing stage of the washing cycle.
As an alternative, operating method of the laundry washing machine 1 may envisage that the control unit 18 estimates/calculates the weight of the laundry currently stored inside in rotatable drum 6 on the basis of the laundry material (for example cotton, synthetic or wool) detected by the laundry washing machine in known ways, or selected by the user, and of the amount of tap water absorbed by the laundry at beginning of the washing cycle.
In a further embodiment, operating method of the laundry washing machine 1 may envisage that the control unit 18 estimates/calculates the weight of the laundry from the value of the current absorbed by the motor for rotating the drum.
According to a less sophisticated implementation, operating method of the laundry washing machine 1 may also envisage that control unit 18 detects /receives information related to the weight of the laundry currently stored inside rotatable drum 6 on the basis of a weight value selected by the user before starting the washing cycle.
For example, the laundry washing machine 1 may carry out several type of half-load washing cycles and several type of full-load washing cycles, all freely and manually selectable by the user via control panel 20. In which case, for example, only two different spin-launch algorithms are stored inside the memory module: the first spin-launch algorithm is univocally associated to all half-load washing cycles and it is selected by control unit 18 when a half-load washing cycle is selected by the user; whereas the second spin-launch algorithm is univocally associated to all full-load washing cycles and it is selected by control unit 18 when a full-load washing cycle is selected by the user.
In other words, assuming that the maximum rotatable drum capacity is 6 kilos, the control unit 18 detects/is informed that the weight of the laundry currently stored inside rotatable drum 6 is 3 kilos if a half-load washing cycle is selected, and operates accordingly. Otherwise the control unit 18 detects/is informed that the weight of the laundry currently stored inside rotatable drum 6 is 6 kilos if a full-load washing cycle is selected, and operates accordingly.
However the way in which the laundry washing machine 1 detects or receives the information of the weight of the currently loaded laundry is not restraining for the functioning of the invention.
The possibility of selecting the spin-launch algorithm to be used during the washing cycle among a number of different spin-launch algorithms each univocally associated to a specific weight-range of the laundry in the drum, has lots of advantages.
Experimental tests conducted by the applicant, in fact, revealed that the use of different spin-launch algorithms each of which is optimized for a specific load of the drum, significantly increases the percentage of the washing cycles in which the spin stage is carried out according to the specifications of the user-selected washing-cycle, with all advantages concerned.
Clearly, changes may be made to the rotary-drum laundry washing machine 1 and to its operating method as described above without, however, departing from the scope of the present invention.
For example, the rotary-drum laundry washing machine 1 may be a top-loading laundry washing machine, or even a front-loading or top-loading laundry washing and drying machine.

Claims

Operating method of a laundry washing machine (1) comprising an outer casing (2), a rotatable drum (6) structured for housing the laundry to be washed and which is housed in axially rotating manner inside said casing (2) for rotating about its longitudinal axis (L), motor means (7) structured for driving into rotation the rotatable drum (6) about its longitudinal axis (L), and a control unit (18) which controls at least said motor means (7); the laundry washing machine operating method comprising the steps of carrying out, in sequence, the washing/rinsing stage and the spin stage of the selected washing cycle, and being characterized by also comprising
- the step of selecting, among a plurality of spin-launch algorithms stored inside a memory module and each of which is univocally associated to a specific weight-range of the laundry loaded inside the rotatable drum (6), the spin-launch algorithm univocally associated to the weight-range in which the weight of the laundry currently loaded inside the rotatable drum (6) is comprised; and

- the step of carrying out the spin stage of the selected washing cycle according to the currently selected spin-launch algorithm.
Laundry washing machine operating method according to Claim 1, characterized by also comprising, before selection of the most appropriate spin-launch algorithm, the step of determining the weigh of the laundry currently loaded inside the rotatable drum (6).
Laundry washing machine operating method according to Claim 2, characterized in that determination of the weigh of the laundry currently loaded inside the rotatable drum (6) comprises the step of directly measuring the weight of the laundry loaded inside the rotatable drum (6).
Laundry washing machine operating method according to Claim 3, characterized in that the direct measuring of the weight of the laundry loaded inside the rotatable drum (6) comprises the step of measuring the weight of the washing tub (3) which houses the rotatable drum (6).
Laundry washing machine operating method according to Claim 2, characterized in that determination of the weigh of the laundry currently loaded inside the rotatable drum (6) comprises the step of estimating the weight of the laundry currently stored inside the rotatable drum (6) on the basis of the laundry material, detected or selected by the user, and of the amount of fresh water absorbed by the laundry at a prefixed phase of the washing cycle.
Laundry washing machine operating method according to Claim 2, characterized in that determination of the weigh of the laundry currently loaded inside the rotatable drum (6) comprises the step of estimating the weight of the laundry currently stored inside the rotatable drum (6) on the basis of the weight value selected by the user.
Laundry washing machine operating method according to Claim 2, characterized in that determination of the weigh of the laundry currently loaded inside the rotatable drum (6) comprises the step of estimating/calculating the weight of the laundry currently stored inside the rotatable drum (6) on the basis of the value of the current absorbed by the motor means (7) for rotating the rotatable drum (6).
Laundry washing machine operating method according to anyone of the foregoing claims, characterized in that each spin-launch algorithm stored in the memory module is provided with one or more specific speed-time paths of the angular speed of the drum specifically designed to detach the laundry from the lateral wall of the rotatable drum (6); and/or with one or more specific speed-time unbalanced-weight detecting paths of the angular speed of the drum specifically designed to determine the unbalanced component of the weight of the laundry currently loaded inside the rotatable drum (6); and/or with one or more specific speed-time weight-reallocating paths of the angular speed of the drum specifically designed to reallocate the laundry loaded inside the rotatable drum (6); and/or with a specific decision-making logic for aborting the spin stage or for reducing the maximum angular speed of the drum during the spin stage.
Laundry washing machine (1) comprising an outer casing (2), a rotatable drum (6) structured for housing the laundry to be washed and which is housed in axially rotating manner inside the casing (2) for rotating about its longitudinal axis (L), motor means (7) structured for driving into rotation the rotatable drum (6) about its longitudinal axis (L), and a control unit (18) which controls at least said motor means (7); the laundry washing machine being characterized in that it comprises a memory module which has stored, inside itself, a plurality of different spin-launch algorithms each of which is univocally associated to a specific weight-range of the laundry loaded inside the rotatable drum (6), said laundry washing machine (1) being structured to select and carry out the spin-launch algorithm univocally associated to the weight-range in which the weight of the laundry currently loaded inside the rotatable drum (6) is comprised.
Laundry washing machine according to claim 9, characterized by also comprising detecting means (18, 19) able to determine the weigh of the laundry currently loaded inside the rotatable drum (6).
Laundry washing machine according to claim 10, characterized in that the rotatable drum (6) is housed in axially rotating manner inside a washing tub (3) located inside the casing (2), and in that said detecting means (18, 19) are able to measure the weight of said washing tub (3).
Laundry washing machine according to claim 10, characterized in that said detecting means (18, 19) are able to estimate the weight of the laundry currently stored inside the rotatable drum (6) on the basis of the laundry material detected or selected by a user, and of the amount of fresh water absorbed by the laundry at a prefixed phase of the washing cycle.
Laundry washing machine according to claim 10, characterized in that said detecting means (18, 19) are able to estimate the laundry currently loaded inside the rotatable drum (6) on the basis of the weight value selected by the user.
Laundry washing machine according to claim 10, characterized in that said detecting means (18, 19) are able to estimate the weight of the laundry currently stored inside the rotatable drum (6) on the basis of the value of the current absorbed by the motor means (7) for rotating the rotatable drum (6).
Laundry washing machine according to anyone of Claims 9-14, characterized in that each spin-launch algorithm stored in the control unit (18) is provided with one or more specific speed-time paths of the angular speed of the drum specifically designed to detach the laundry from the lateral wall of the rotatable drum (6); and/or with one or more specific speed-time unbalanced-weight detecting pats of the angular speed of the drum specifically designed to determine the unbalanced component of the weight of the laundry currently loaded inside the rotatable drum (6); and/or with one or more a specific speed-time weight-reallocating pats of the angular speed of the drum specifically designed to reallocate the laundry loaded inside the rotatable drum (6); and/or with a specific decision-making logic for aborting the spin stage or reducing the maximum angular speed of the drum during the spin stage.