Patent Application
20250084579
The present disclosure relates to a method and apparatus for mitigating an out of balance mass in a laundry apparatus.
Typically a laundry machine (laundry apparatus) operates in one of two modes.
During the spin mode, forces can cause the laundry load can to adhere to the inner surface of the drum and to rotate with it. This can cause an out of balance (OOB) condition where the mass of the laundry load is not evenly distributed about the centre of rotation of the drum while the laundry apparatus is operating in spin mode. This is undesirable. Spinning the drum in the out of balance condition can cause undesired vibrations and resonances that result in noisy operation and potential damage to the drive and suspension systems of the machine.
It is therefore an object of the present invention to provide an improved method and/or apparatus for mitigating an out of balance laundry load in a laundry apparatus which goes at least some way toward addressing one or more of the problems mentioned above and/or at least provides the public with a useful alternative.
It is an object of the present invention to provide a method and/or apparatus for mitigating an out of balance mass in a laundry apparatus.
The present invention may be said to comprise a method of mitigating an out of balance washing load in a washing machine with a horizontal axis drum comprising: determining an indication of an angular and optionally a radial position of a OOB mass of the washing machine drum, and controlling rotational speed of the drum so that, as the drum and OOB mass rotates, a rotational speed of the drum is varied relative to a usual speed based on the OOB mass so that an outward radial force on the washing load reduces below the inwards radial force and/or of gravity.
Optionally the rotational speed of the drum is varied for less than a revolution of the drum.
The present invention may be said to consist in a method of mitigating an out of balance washing load in a washing machine with a horizontal axis drum comprising: determining an indication of an OOB mass of the washing machine drum, and controlling rotational speed of the drum so that, as the drum and OOB mass rotates, a rotational speed of the drum is varied, within one revolution of the drum, relative to a usual speed based on the OOB mass so that an outward radial force on the washing load reduces below the inwards radial force and/or of gravity.
Optionally determining an indication of an OOB mass comprises determining an angular position of the OOB mass.
Optionally wherein the rotational speed of the drum is varied based on an angular position of the OOB mass and/or washing load.
Optionally the angular position of the OOB mass and/or washing load is determined based on: a time, and/or an angular position of the drum, as the drum rotates.
Optionally the rotational speed of the drum is reduced also based on the radial position of the OOB mass.
Optionally the rotational speed of the drum is controlled using a control signal with a profile that varies from a normal control signal.
Optionally the control signal varies based on:
Optionally the control signal varies based on the angular position of the OOB Mass and/or washing load as the drum rotates.
Optionally the control signal to control a rotational speed of the drum comprises:
Optionally the control signal profile creates a rotational speed profile of the rotating drum that creates a target region which redistributes an OOB mass and/or washing load in the target region.
Optionally the target region comprises and angular span and a radial extent.
In another aspect the present invention may be said to comprise a laundry apparatus comprising: a drum, a motor to rotate the drum, one or more sensors, and a controller that receives input from the sensors and controls the motor to rotate the drum, wherein the controller is configured to mitigate an out of balance washing load according one or more methods set out herein.
In another aspect the present invention may be said to comprise in a method of mitigating an out of balance laundry load in a laundry machine with a horizontal axis drum, comprising the steps of:
Optionally the rate at which drum speed is decreased to a speed below satellisation speed is more rapid than the rate at which drum speed is subsequently increased to a speed above satellisation speed.
Optionally the method further comprises the step of:
Optionally the step of varying the drum speed coincides rotation of the drum below satellisation speed with the position of the out of balance mass being at, near, or passing through, a high point in its rotation about the horizontal axis of the drum.
Optionally the method further comprises the step of:
Optionally the angular extent of the target zone is between about 0-90 degrees in either direction relative to the position of the out of balance mass; or optionally between about 0-45 degrees, about 0-30 degrees, about 0-15 degrees, or about 0-5 degrees in either direction relative to the position of the out of balance mass.
Optionally the radial extent of the target zone is between about 25-100 percent of the radius of the drum; or optionally between about 40-100 percent, about 60-100 percent, about 80-100 percent, or about 90-100 percent of the radius of the drum.
Optionally one or more selected from the following are used as inputs from which to determine the position of the out of balance mass.
Optionally the position of the out of balance mass is determined using:
Optionally the position of the out of balance mass is determined using only motor data.
Optionally, during the step of varying the drum speed by sequentially decreasing and then increasing the drum speed below and then above satellisation speed, the rotational speed of the drum is controlled using a control signal with a profile that varies from a previous normal and/or constant control signal profile, and optionally has a pulsed profile.
Optionally the control signal varies based on one or more selected from:
Optionally the control signal comprises one or more selected from:
Optionally the control signal profile creates a rotational speed profile of the rotating drum that selectively causes laundry load in the drum to drop under gravity;
In another aspect the present invention may be said to comprise in a laundry apparatus comprising:
It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7).
The term “comprising” as used in this specification means “consisting at least in part of”. Related terms such as “comprise” and “comprised” are to be interpreted in the same manner.
This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.
Embodiments will be described with reference to the following drawings, of which:
Various embodiment of a laundry apparatus will be describe for assessing and mitigation out of balance (OOB) washing loads.
First, and explanation of out of balance washing loads in a laundry apparatus (also termed “laundry machine” or “washing machine”, which can be used interchangeably) will be provided.
Typically a laundry machine (laundry apparatus) 1 operates in two distinct modes during its cycle:
Referring to
In order to resolve or improve (more generally “mitigate”) the OOB condition, the washing load may be redistributed more evenly about the centre of rotation. For example:
In the present embodiments, each of the OOB conditions shown in
The OOB mass 4 is a notional mass with a notional position (a position that can change over time) that is not a mass of a real washing load 2 or its distribution, but provides a model/representation of such a real mass 2. Rotation of the out of balance washing load (e.g. as represented by rotation of the OOB mass) causes an oscillatory excitation of the drum (which is suspended upon springs inside of the laundry apparatus) and thus an oscillatory motion of the drum in a plane orthogonal to the axis of rotation, here represented by the arrows X and Y. The purpose of resolving or improving (mitigate) the OOB condition is, at least in part, to reduce the magnitude of this motion.
An exemplary apparatus for carrying out the method of the present embodiments is described in relation to
In general terms, as shown in diagrammatic form in Figure the 3 laundry apparatus 1 (in this case a horizontal axis/front-loader laundry apparatus) has a motor 10, a horizontal axis internal drum 11 and an outer drum 5 suspended (e.g. by springs 18) in an outer cabinet (“housing”) 12, a weight sensor 14, and a motor sensor 15. The motor drives the drum to rotate and rotationally oscillate in the axial direction along the x axis (see insert
Referring to
The accelerometer 17 (if used), weight sensor 14 (if used), motor speed 15 (if used) and/or position sensor (if used) and any other component that provides information from which the OOB condition can be characterised is termed an “OOB sensor”. The OOB sensors might be used for other assessment and control also, in addition to OOB assessment and OOB mitigation. As described previously, the motor 10 itself can be used as an OOB sensor, to the extent that data from the motor (such as current, torque, position, speed and temperature) can be processed to provide information which may alone, or in combination with other information, enable the OOB condition to be characterised.
For example, the controller 16 could be programmed to take one or more of the following actions to resolve or improve (mitigate) the OOB mass 4, thereby to resolve or improve (mitigate) the OOB condition:
Preferably the actions mitigate (e.g. eliminate or at least reduce) the OOB condition/mass 4 within one spin revolution of the drum, or within a small number of revolutions. Taking the actions can redistribute the real washing load mass 4, which can mitigate the OOB mass 4, thus mitigating the OOB condition. Reference to redistribution means some movement of real washing load. This can happen due to e.g. slowing the rotation such that redistribution happens due to gravity, friction, centrifugal action, bounciness or other forces.
Referring to
It will be appreciated that
A method of:
The method implemented by the controller can generally follow steps such as those shown in
The controller 16 starts the spin cycle of the washing machine 1, by operating the motor 10 to spin the drum 11, step 60. The controller 16 is configured to drive rotation of the drum during the spin cycle according to a (e.g. predetermined) angular speed profile. For example, the controller may operate the drum to spin according to a spin cycle speed profile as shown in
The OOB method of the present embodiments is implemented at one or more OOB decision points, a decision point typically being at (but not limited to) one of the speed plateaus, where the OOB Condition is substantially “steady”. In this example, the method is performed at the first speed plateau 81B, which might typically be around about 93 rpm, but that is not limiting and is by way of example only. Alternatively, the method might be performed at a subsequent speed plateau e.g. 82B, 83B, 84B or a higher rotational speed. For example rotational speeds could be as high as 500 RPM (for example 100, 200, 300, 400 or 500 RPM). The spin speed is increased through at least the first resonant frequency of the suspended assembly and up to the first speed plateau 81B, by which point the load is centrifuged 43 so it is plastered 41 (due to centrifugal force) against the inside circumference of the drum 11, step 61. This can be termed as full “satellisation”.
At a suitable point in the spin cycle 80 (such as at the first plateau 81B), the controller 16 determines an out of balance (OOB) parameter (e.g. OOB Mass 4 and/or OOB condition), step 62. This could be information indicative of the position (e.g. angular position) and/or magnitude of a OOB Mass 4, and may additionally include information as to the distributed mass of the suspended assembly, and/or information about where the load mass is located along the axial direction of the drum. This OOB parameter can be determined in any of the methods known in the art for detecting and characterising out of balance loading in a laundry apparatus.
After determining the OOB parameter, the controller 16 determines if the OOB parameter (e.g. the OOB condition and/or OOB mass 4) is acceptable or, therefore whether redistribution is required, step 63. Again, there are various methods known in the art for determining whether the OOB parameter is acceptable, or whether the parameter exceeds certain thresholds above which vibration or movement of the drum is excessive or is predicted to become excessive at higher speeds. In general terms, if the OOB parameter is above a threshold or otherwise on the wrong side of a threshold, OOB condition is determined; and if the OOB parameter is below or otherwise on the correct side of a threshold, OOB condition is resolved. For example, such methods typically take into account whether the magnitude of the OOB Mass 4 exceeds a certain threshold, and the threshold to be exceeded may vary depending on where load mass is concentrated along the axial direction (with load mass concentrated near the front of the drum (distal-most from the bearings) considered to be more problematic than load mass concentrated near the rear of the drum and proximate to the bearings). If the OOB parameter is acceptable (e.g. OOB Mass is below the threshold), then the spin cycle is continued as per usual known to those skilled in the art, step 64. For example the spin speed may be advanced to the next speed plateau, where evaluation of the OOB parameter is repeated in the manner described above. However, if the OOB parameter is not acceptable, further action is taken to improve or resolve (that is, mitigate) the OOB Condition before increasing the drum speed.
The controller 16 then determines the angular position of the OOB Mass, step 65.
The OOB mass 4 and its movement is described further with reference to
In order to carry out the method of the present embodiments, the controller 16 determines the angular position of the OOB Mass 4 as the drum revolves, step 65. For example:
Conversely, the motor torque reaches a minimum when the OOB Mass is at a 270 degree angular position, and thus, under gravity, exerts a positive torque in relation to the counter-clockwise motion of the drum. The time at which the OOB mass reaches the 180 degree angular position (i.e. the highest point during a revolution) can be estimated as occurring roughly half-way between the occurrence of maximum and minimum motor torque.
The motor speed and/or position sensor 15 can be used for determining the angular velocity of the motor 10. For example a hall effect sensor or encoder could be used. However it is alternatively possible to use data from the motor, such as current, (or some other type of sensorless control methodology) to estimate the position and/or speed (that is, angular position and/or angular velocity) of the motor.
In at least some embodiments, in order to carry out the method of the present embodiments, the apparatus provides a method and/or apparatus by which to determine mass of the washing load 2. The weight sensor 14 can be used for determining the mass of the washing load. For example, the weight sensor 14 may be located in the feet 30 of the washing machine (see
So, based on the above, the controller 16 monitors the spinning drum 11 and determines and/or receives an OOB parameter, which indicates the presence/absence and/or severity of an OOB Condition/mass of the drum 11. As part of that the controller 16 may further determine and/or receive information indicative of the approximate position (that is, angular position relative to a datum, such as the rotational bottom/notional 0 degree angular position such as in
It should be noted that while the specification refers to the angular position of an OOB mass 4, this OOB Mass is a notional point mass 4 at the circumference of the drum, that is a model/representation of the resultant force due to real OOB conditions (that is, due to a mass of a real washing load 2) in the drum. Thus there may not be an actual mass at the angular location of the OOB Mass 4—for example, as shown in
In general terms, to attempt to improve or resolve the OOB Condition, and attempt is made to redistribute the actual washing load (real mass) 2 so that the OOB Mass 4 is reduced or eliminated. The method and apparatus of the present disclosure determines a suitable variation of rotational speed and varies the rotational speed (also termed “angular speed”) of the washing machine drum 11 at a target angular position of the drum rotation cycle, step 66. The variation of rotational speed is for less than/occurs within one revolution of the drum. Varying the rotational speed of the washing machine drum may redistribute the actual load, and as such the notional OOB Mass 4 is reduced or disappears. If the OOB Mass 4 reduces/disappears, it can be inferred that the actual washing load 2 has been at least partially redistributed which leads to an improvement or resolution of the OOB condition. At a general level, the method proceeds on the basis that by redistributing real washing load mass 4, which is modelled by the OOB Mass 4, there is a higher percentage chance of improving or resolving the OOB Condition.
The controller determines, step 66, an appropriate rotational speed variation to mitigate OOB based on the received information that:
The controller 16 controls, step 66, the rotational speed of the washing machine drum 11 by controlling the speed of the motor 10 based on the determined rotational speed based on the OOB condition/mass 4 that the controller 16 determines and/or receives input on.
For example, the rotation speed variation can be a speed profile (“mitigation speed profile”), that comprises a varying speed over time/angular position of the drum 11. In general terms, a speed profile could be as follows. During a revolution of the internal drum 11, as the angular position of the OOB Mass (while rotating with the drum): a) approaches, b) is in the vicinity of, c) is at a target angular position, and/or d) leaves a target angular position 40 of the washing machine 10), the angular speed of the washing machine drum 11 is reduced. The angular speed is preferably reduced for less than one revolution of the drum, before it is returned to normal.
Preferably, the target angular position is at a point above halfway (e.g. above point R/90-degree angular position shown in
So, when the OOB mass 4 reaches a target angular position (or as the OOB mass approaches the target angular position), the drum 11 is decelerated to a second angular speed, and re-accelerated after leaving the target angular position back to its first or increased angular speed, causing a “speed dip” to be executed.
Deceleration of the drum to speed decreases the centrifugal force 43 on the laundry in the drum, allowing at least some of the laundry load mass 4 in the top half of the drum 11 to drop under gravity G and land at an alternate peripheral location of the drum. It is expected that the mass 2 may spread out as it falls and/or fall to a location where there was previously a localised area of low clothing mass (for example as shown in
Note, while an angular position of a OOB mass 4 is used as the reference point for changing speed, it could actually be a target region 70, such as described later with reference to
In some embodiments, the speed dip is executed so that the rate of deceleration is more rapid/occurs over a shorter time period than the subsequent rate of acceleration/time to return to satellisation speed. For example, a drum spinning at approximately 93 RPM may be decelerated at a rate of around 1000 RPM per second, and then subsequently accelerated at a rate of around 50 RPM as it returns to satellisation speed.
In this regard it has been found advantageous to use the mass of the laundry load/drum to aid in execution of the motor speed dip, such that deceleration and acceleration during the speed dip may be synchronised with the rise and fall of the OOB mass during its rotation. For example, with reference to
As one example (without limitation), during a spin cycle, the washing machine drum 11 is rotating at a first angular speed S1 at which the washing load is fully satellised. Then, during a single rotational cycle, as the angular position of the OOB mass (while rotating with the drum) reaches a target angular position (see later for detail, but as an example this could be 90 degrees in
Once the controller controls the motor to the speed profile, the controller 16 measures OOB mass 4/OOB condition again, step 62, and if not acceptable, step 63, determines and implements a rotational speed variation again; or if it is acceptable, step 63, continues with the normal spin profile, step 64. For example, After, or in parallel with, executing the “speed dip”, the Out of Balance parameter will be monitored and determined again, step 62. If the speed dip has been effective in redistributing real load mass 2 such that the OOB Condition is resolved or improved to a level where the OOB parameter (e.g. OOB mass 2) is acceptable, then spinning can continue according to the usual profile 80, steps 63, 64. However, if the OOB parameter is unacceptable (indicating that a problematic OOB Condition still exists), step 63, the mitigation speed profile can be applied again to execute a further speed dip or series of speed dips. Of course, because of redistribution of the real load mass 2, the OOB Mass 4 may have changed in position, size and other parameters, and therefore the mitigation speed profile may also change such as the initiation timing, speed variation and/or target position/region for the new OOB Mass 2. However in some embodiments the mitigation speed profile is set (e.g. target position/region and corresponding speed variation), and the same mitigation speed profile is applied repeatedly with only the timing of the signal to be altered according to the angular position of the OOB Mass 2.
In more general terms, the varying of the rotational speed of the washing machine at target angular positions of the OOB mass 4 will, if necessary, be repeated until the controller 16 has determined that the OOB Condition/mass 4 has been sufficiently improved or resolved (e.g. OOB parameter is less than a threshold or otherwise on the correct side of a threshold), at which point rotation of the drum 11 will return to the predetermined angular speed profile of the spin cycle. For example, referring to
Referring to
In this case, by way of example, the OOB assessment can initially take place at the first spin speed plateau 81B, in
b) Deceleration to S2 should effect a sufficient reduction in centrifugal force that at least some of washing load mass is allowed to fall under gravity G and land at an alternate peripheral location of the drum. S2 should, accordingly, be below the satellisation speed.
In some embodiments S2 could be obtained empirically, noting that the time taken to effect the redistribution can be reduced by minimising the difference between S1 and S2.
The controller 16 further determines a mitigation speed profile that will, by the desired time T1 (corresponding to a certain angular position of the OOB Mass 4), slow the drum 11 rotation to a speed S2 below the satellising speed, step 66, with the effect that real mass located within a “target zone” of the drum may fall under gravity G and be redistributed at an alternative peripheral location.
The mitigation speed profile varies the motor from the norm—the normal motor speed being one that rotates the drum at a constant rotational speed. The mitigation speed profile of this example has one or more of:
As shown in
By way of example, with reference to
It will be appreciated that alternatively to driving the motor to vary rotational speed over certain time intervals, it is additionally or alternatively possible to drive the motor to vary rotational speed according to the angular position of the rotor of the motor itself (which is directly coupled to the laundry apparatus drum). In which case the control signal may include such parameters as a start and/or stop angular position, and/or a range of angular positions of the rotor over which rotational speed is varied, and/or a target angular position of the rotor for arriving at speed S2, and/or a range of angular positions of the motor during which the motor angular speed remains at S2. In general terms as skilled person will appreciate that determining to vary angular speed based on time or determining to vary angular speed based on angular position (of the drum) are interchangeable and just a matter of the control/sensor arrangement used. The examples herein are not limiting, and any manner of control that implements a speed variation at a suitable position/range of drum rotation can be used.
In this embodiment, the controller 16 determines the angular position of the OOB Mass, step 65.
At a general level, the OOB method proceeds on the basis that by redistributing real washing load mass 2 located at or near the OOB Mass 4, there is a higher percentage chance of improving or resolving the OOB Condition than can be achieved by randomly redistributing real load mass, or by redistributing real load mass that is distant from the OOB mass. That is, by decelerating the drum to S2 at about the same time that the OOB Mass reaches an 180-degree angular position, there is created a notional “target zone” 70 (see
In this embodiment the motor speed control signal profile is specified so that it controls the motor drum 11 so the rotational speed reduction occurs at a range of angular drum rotation positions so that (at the radial and/or angular position of the OOB mass 4) the radially outward centrifugal force on the real mass 2 is less than the radially inward/gravitational force G on the real mass 2, so that the real mass 2 will de-satellise and fall away from the position it is in. It may fall directly down and/or tumble, in a manner that might redistribute the washing load and remove the OOB mass.
Referring to
So in general terms, the motor speed control signal can be varied, to alter the speed profile of the rotating drum, to create a target region 70 being defined by an angular span C and/or an angular start B and stop position A, and/or a radial span R being the radial extent from the centre of the target region.
It has been found that the angular extent of the target zone can be altered by manipulating the profile of the control signal as follows:
It can be appreciated that if the dip in motor speed is executed very rapidly, then there will be only a momentary reduction in centrifugal force as the OOB mass 4 passes the top of the drum 11, and only real washing mass located in the close vicinity of the OOB mass (for example mass located in the target zone (shaded region) in
Similarly, it is found that lengthening the amount of time spent at speed S2 could increase the angular extent of the target zone. However there is a limited time that can be spent at speed S2, seeing as the motor speed must return to S1 (or at least to a speed at which the load is satellised) inside of the time taken for the drum to complete a single revolution, and preferably returns to S1 (or at least above satelisation speed) within the time taken for the drum to complete a half revolution beyond T1.
This is shown more generally in
One reason that it may be desirable to alter the angular extent of the target zone on either side of the OOB Mass, is that, as explained in relation to
It has further been found that the radial extent of the target zone can be altered by manipulating the profile of the control signal as follows:
Theoretically the angular speed needed to satellise the OOB Mass is dependent on the radius R of the drum (shown in
However, if there is a full load of laundry in the drum 11, then not all of the real mass 2 will be located at the radius R of the drum. In this case the OOB condition may be improved or resolved by redistributing real mass located at a lesser radius R2 of the drum (for example, as shown in
In one example, the mass of the washing load may be measured (by methods previously described), and a lesser radius R2 (compared to the maximum value of R) may be assigned if the measured load mass exceeds some threshold which is designated to indicate a “full” or large load. The lesser radial value R2 can be assigned because a more massive/full load is likely to have load mass located at a smaller radius R2 (for example, as shown in
Therefore in the manner described above it is possible to calculate a control signal/speed profile that will slow the drum to a speed S2 below satellisation speed to effect redistribution of real mass within a defined target zone, the target zone being defined in terms of an angular and radial extent with respect to the angular position of the OOB Mass and the drum radius R.
An example of how an appropriate control signal profile is determined can be given in relation to a laundry washing machine with a washing load capacity of approximately 8 kg and a drum radius of approximately 0.262 m, spinning at the first speed plateau of the wash cycle spin speed profile at a rotational speed S1 of around 93 RPM (9.7 rad/sec). Prior to beginning the spin cycle, it has been determined that the mass of the washing load is around 6 kg:
d) The control signal may be initiated at a time Ti just prior to T1, for example time Ti may be approximately 0.15 secs after Ttorque_max. Rates of deceleration are determined in order to give the necessary reduction in angular speed from S1 at time Ti, to S2 at time T1, and a roughly equal rate of acceleration may be determined to increase angular speed back to S1. Because the rates of deceleration and acceleration are sharp, it is only real load mass located within the vicinity of the OOB Mass (i.e. within 40 degrees either side of the angular position of the OOB Mass) that is caught within the “target zone” for redistribution. Preferably the deceleration and re-acceleration is completed within 0.33 secs of Ttorque_max (which is the time it would take the OOB Mass to travel a half revolution, at 93 RPM, from an angular position of 90 degrees to 270 degrees).
However, as previously explained, deceleration of the drum to speed S2 may occur slightly before or after the time T1 at which the OOB Mass is estimated to reach its 180 degree angular position. Experiments have found that initiating the control signal at a time Ti of between 0.15-0.2 seconds after time Ttorque_max can result in an improved chance of resolving or improving the OOB Condition by redistributing items located within the vicinity of the OOB Mass (compared to redistributing the laundry load at random).
Performing several speed dips in series may increase the chance that the OOB Condition is sufficiently resolved or improved by the time that steps 62 and 63 are repeated. As steps 62 and 63 take some time to perform, it is desirable to minimise the number of times that they must be performed during the redistribution process. For example, in some laundry apparatus, it has been found that using the above-described method for redistribution, OOB laundry loading can be acceptably improved or resolved inside of an average time of around 65 seconds.
In some embodiments, the OOB parameter is monitored/determined and assessed for acceptability (i.e. steps 62 and 63 are repeated) after every time that a speed dip (steps 65 and 66) is performed. However, in some embodiments, a series of speed dips may be performed (i.e. steps 65 and 66 are repeated several times over several different revolutions of the drum) before steps 62 and 63 are repeated. Where several speed dips are performed in series, the angular speed of the drum may each time return to its original angular speed of S1, or optionally at least to a speed which is above the satellisation speed and which might, for example, be a slightly slower speed than S1.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021904088 | Dec 2021 | AU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2022/062341 | 12/16/2022 | WO |
