The invention relates to a laundry washing machine comprising a washing reservoir for a washing solution and a means to agitate the washing solution present in the washing reservoir.

Washing machines often comprise means to agitate the washing solution in order to improve the effectiveness of the washing process. For this purpose, in conventional washing machines the washing machine is equipped with a rotating drum or a vertical rotor in an upright drum.

Such conventional washing machines, however, are by and large not suitable for doing small washes, the so-called 'hand washes'. Furthermore, the conventional washing machines occupy much space and they are very heavy making them less suitable or not suitable at all for small spaces and it is difficult to transport them as well. There is also a chance of damaging the laundry.

Consequently, small hand washes, as the word already indicates, are often done by hand. However, this exposes the hands to washing solution, water, soap and other detergents.

Vibratory action cleaning devices are known from documents US-A-4 167 341 and FR-A-1077541.

It is an object of the invention to improve, by means of a laundry washing machine, the very frequently used method of doing 'hand washes', by which the hands need to be less exposed to the washing solution, water, soap and other detergents.

For this purpose the laundry washing device according to the invention comprises the features of claim 1.
When in operation, the table vibrates the bucket at a low frequency. In this way the washing solution starts to vibrate, which enhances the washing effect. By applying low-frequency vibrations, the laundry sustains considerably less damage compared to the use of conventional rotating systems. That way the probability of damaging the laundry is reduced to nil and wear-and-tear is noticeably avoided. This can be explained by the fact that the laundry is not flung around but rather floats in the liquid solution, whereas the vibrations do their work in the liquid solution with an appropriate frequency and amplitude. The washing solution is, so to speak, swung through the fabric while at the same time dirt is removed. In contrast to ultrasonic vibrations with very small motions, the effect on laundry has proven to be much greater with low-frequency vibrations with much larger motions (amplitude). The hands do have to be or need to be much less exposed to the washing solution, water, soap or other detergents.

The laundry washing machine according to the invention affords one or more of the following advantages, further explained in the pages that follow; however, with some types of constructions, to a larger or lesser extent, specific advantages can be rendered:

• Very well suited for laundry for which a traditional washing machine is less suitable (or unsuitable). Notably for delicate laundry for which the conventional washing machines are less suited, on account of the roughness with which the laundry is treated, the washing device according to the invention features its specific advantages.
• Small dimensions. Easy to transport. Compact and space-saving design. Very accessible. The detachable bucket makes it easy to move the washing device and to fill it with washing solution and laundry.

• If necessary or desirable, the volume in which the laundry is put, i.e. the bucket, is easy to clean and to detach from the base part.
• Ideal for small wash loads or even for a single piece of laundry.
• Typically suitable for fme / delicate laundry such as lingerie. Clothing hooks are not a problem.
• Laundry moves relatively little, the detergent mainly moves.
• Laundry retains its colour, the colour even improves.
• Short washing time.
• Low energy consumption. The energy consumption of the washing device according to the invention has revealed to be relatively low.
• Water-efficient. The amount of water in the bucket suffices.
• Economical use of detergent.
• Stand-by anywhere.

In particular the invention features:

• A laundry washing machine that is easy to transport and/or operate. A bucket is quite simple to exchange which makes the washing device easy to operate.
• An efficient washing device of limited size that therefore occupies little space.

The laundry washing machine according to the invention is particularly suitable for applications in those situations in which it is important to reduce the dimensions and the weight of the washing device and/or keep them restricted, such as, for instance in motor and sailing yachts, caravans, campers or camping equipment, lorries with a sleeping cabin, small living accommodations, such as student housing etc.
The laundry washing machine according to the invention uses a washing process by means of low frequency vibrations. In this respect, low frequency means vibrations below approximately 500 Hz. It is indeed a well-know fact that it is possible to clean products by means of ultrasonic vibrations, but the inventors have come to the realization that the advantageous effect of using ultrasonic vibrations on laundry is very limited or not effective at all. The low frequency(ies) used in the washing device according to the invention do indeed have a positive effect on the washing of laundry. In preferred types of constructions the drive, while in operation, vibrates with a frequency of less than 100 Hz, preferably with a frequency between 10 and 50 Hz. In this frequency range the positive effect of the vibrations on the washing effectiveness is quite considerable and the energy required to generate the vibrations is relatively low.

Within the scope of the invention many types of constructions are possible. A number of possible and preferred embodiments of the invention are:

• The table contains a coupling means to detachably fasten any random bucket. With this general type of construction the bucket is not necessarily supplied with corresponding coupling facilities. Such a general coupling facility attached to the table enables the connection of a bucket. The advantage of this type of construction is that existing, already previously purchased or available buckets can be used. Such a general coupling facility can, for instance, be a clamping strip with an adjustable diameter fastened to or on an upper surface of the table for clamping the bottom flange of the bucket, or clamping strips fastened to the table that can be suspended over the bucket and subsequently tightened. As opposed to the advantage of a wide applicability, however, there is the disadvantage that there are very many different types and sizes of buckets on the market that are not all designed in such a way allowing them to be easily connected and of which some of them are less suited to vibrations.

With a preferred type of construction the laundry washing machine the bucket and table are provided with compatible coupling means. With these types of constructions the washing device contains an assembly of a bucket and a base with table, whereby the bucket and table are equipped with compatible, corresponding coupling means. This assures a good mechanical connection between bucket and table. 'Detachable connection' and 'coupling means' are understood to mean operations and facilities enabling and allowing an average user to connect and disconnect the bucket from the table when operating the washing device. It should be noted that in traditional devices parts of a washing machine indeed sometimes are detachable by an appropriate and competent technician, for instance, as a replacement of defective parts, but that normally the user who is a layman is not authorized to do this, and that the coupling facilities have also been constructed in such a way, often or frequently internally in the washing machine, that a layman will or cannot do this without considerable risk of inflicting damage. A replacement of this kind in conventional washing machines takes place for inspection purposes and/or the repair of possible defective parts. According to the invention, the coupling facilities are constructed such that connecting and disconnecting the bucket from the table can be performed by the consumer under normal use of the washing device.

Preferably the bucket is made of a sturdy material, such as metal, for instance drawn steel or hard plastic. Flexible materials, such as soft plastic or rubber, suppress vibrations significantly, which reduces the efficiency.

In this context it is remarked that a washing machine has been disclosed, among others, in the patent specification UK 875,201, wherein the washing machine consists of a housing of one piece construction, in which a rubber interior drum is firmly fastened. Within the housing, underneath the rubber interior drum, and firmly connected to the rubber interior drum, a vibrating element that vibrates the rubber interior drum is installed. Here, however, there is no evidence of a detachably connected bucket.

The rubber interior drum is firmly connected to both the top and the bottom, on one side, at the bottom, being firmly connected to the vibrating unit by means of a metal plate encased in the bottom of the rubber interior drum. The metal plate is connected with screws to the vibrating unit. On the other side, at the top, the rubber interior drum is connected to the housing of the washing machine. In the prior art washing machine the interior drum is made entirely or partly of flexible material and fastened to both the vibration unit and the housing. This suppresses the vibrations with the result that much of the energy supplied is converted into vibrations of the interior drum, not into the water inside the fixed interior drum. Consequently, the effectiveness is low.

In am embodiment the washing device according to the invention comprises a loose base part containing the drive for vibrating. With this type of construction the washing device can easily be transported.

As an alternative embodiment, the laundry washing machine according to the invention includes a base part that is built into a larger entity, such as a kitchen or washing unit. With this type of construction, as part of the invention, the word 'base part' should be broadly interpreted, that is to say, as the part of the washing device that contains the table on or to which the detachable bucket is fastened while in operation. The base part of the unit in such type of constructions is designed in such a way that it can be built into, for instance, a working surface such as a kitchen work top. In this respect it may be compared to a hot plate combination.

This embodiment of the laundry washing machine according to the invention is notably advantageous for objects in which the available living space and/or water consumption is very limited. Examples of such objects are boats and vehicles with living and/or sleeping quarters, such as caravans, campers, motor and sailing boats. The invention therefore also relates to a boat or vehicle furnished with a washing device whereby the base part is built into a section (for instance, the kitchen unit or the washing section) of the boat or vehicle. The detachable bucket of the laundry washing machine according to the invention can be used for multiple purposes and can also be put to good use when detached and while not being utilized as part of the washing device and therefore it does not occupy extra space. The built-in base practically does not take up any living space. The invention therefore makes it possible to furnish a boat or vehicle with a washing device without the washing device taking up (much) space. The conventional washing machines occupy so much space and consume so much water that they cannot or can hardly be used in boats or vehicles, unless big or very big types of boats or vehicles are involved.

In preferred embodiments of the invention a (transparent) cover may be included in combination with a (laundry) immersion mechanism. The laundry immersion mechanism prevents the laundry from floating caused by entrapped air bubbles which could hamper the washing effectiveness. In a preferred embodiment, the cover can be removed, allowing the placement of a wringer, provided the drive has been switched off.

Preferably the base is provided with a hand grip with which the base, with or without bucket, can be lifted and/or transported. The hand grip can also serve to carry accessories such as a wringer. During transport this hand grip can be folded down so that little space is required. Preferably the hand grip is protected against undesired hinged movements by means of a self-closing lock. The bucket can be stored, respectively taken along either separately or along with other buckets.

In a preferred embodiment, the drive comprises a frame with two shafts that run parallel to each other, with each of the shafts having an opposite direction of rotation. This manner of generating low-frequency vibrations yields a substantial rate of efficiency > 75%.

These and further aspects of the invention are described in the following pages and are illustrated by means of drawings:

• The drawings illustrate:
  • Figure 1: an exploded view of the device according to the invention;
  • Figures 2A and 2B: an exploded view from above and from below of a base part of the device according to the invention;
  • Figure 3: a schematic exploded view of a table in accordance with an embodiment of a device according to the invention;
  • Figure 4: an exploded view of a drive for a device according to the invention;
  • Figure 5: an exploded view of a detail of a type of construction of a drive of or for a washing device according to the invention;
  • Figure 6: a further illustration of a bucket of a washing device according to the invention;
  • Figure 7: a further illustration of a base part with drive of or for a washing device according to the invention;
  • Figure 8: a drive with bucket of a washing device according to the invention;
  • Figure 9: a base part suitable for installation in, for instance, a boat or a vehicle;
  • Figure 10: a washing machine as known from UK 875,201.

The Figures are example Figures. Equivalent parts are, as a rule, marked with equivalent reference numerals.

Figure 1 illustrates a schematic exploded view of a device according to the invention. Device 1 comprises a base part 2 and a bucket 3. The base part 2 is equipped with a table 4 onto which the bucket 3 can be placed. Base 4 features an on/off button 5. In this preferred embodiment bucket 3 features a coupling means 6 that is compatible with a coupling means 7 on table 4. The coupling facilities can, for instance, together form a threaded joint or a bayonet fitting. In this preferential example bucket 3 is provided with a (transparent) cover 8 and a handle 9 whereby the handle 9 is furnished with a presser 10, which keeps the cover pressed down against the bucket when the handle is in a swing-down position and which releases the cover when the handle is in upward position. Preferably the washing device also occupies little space height-wise and can be placed on the floor or, for instance, on or in a sink. In preferred embodiments the inside of the cover 8 is provided with a laundry immersion mechanism, not shown here. A laundry immersion mechanism can, for instance, be configured with a number of pins or as a grid fastened to a pin on the inside of the cover. This keeps the laundry immersed into the washing solution while the device is in operation and prevents the laundry from floating on top of the liquid solution as a result of entrapped air bells.

Connection hoses for the supply and the drainage of liquid are preferably not used. This rules out any rupture or leakage of hoses, also in the long term, which increases the level of safety.

The operation of the device is preferably simple. This is exemplified by the on/off button 5. Preferably an automatic timer is provided for, meaning that after a period of time the machine will automatically stop.

Preferably the base part is equipped with 1 or more vibration absorbers that rest on the inside edge of the base to support the device at the bottom (see Figure 2B, feet 12).
Furthermore, provisions have preferably been made for a vibration/sound absorber between the drive inside the base and the internal parts of the base.
Some dimensions and further key indicator values of preferential constructions are shown in the table 1 below: - Contents of the bucket : approx. 10 - 11 liters - Volume of the washing solution: 4 - 9 liter - The vibration frequency : below 100 Hz, preferably in the range of 10-50 Hz, more preferably between 15-30 Hz - Electric power required : for example between 5 and 25 Watt, max. 50 Watt - The vertical amplitude centre table: 0.5 - 4 mm (top-top) - The waveform : Linear vertical - (possibly also in other directions) Circular, at any rate, arc-shaped vertical Combination of them.

After washing, if desired, the bucket can remain on the washing device or be removed again (with contents). After removal of the bucket the laundry can easily be taken out of the bucket and subsequently the washing solution can be poured out.

After placing the electric wringer, provided the washing device is equipped with a wringer, the wash can be fed through it while the surplus washing solution flows back into the bucket and, if desired, it can be used again.

In order to obtain no or little loss of movement, preferably a good connection should be provided between table 4, which is connected to drive 11 and bucket 3. In a preferred embodiment this connection is effected by a (partial) screw thread 7 that is compatible with the (likewise partial) screw thread 6 underneath bucket 3. By applying at least 1 elastic element (for instance an O-ring) between the table and the bucket, the stability of such a connection can be enhanced, which improves the quality of the energy transmission and also reduces unwanted vibrations.
In another embodiment the coupling between table and bucket is realized by means of a bayonet connection.
In still another embodiment the coupling between the table and the bucket is effected by means of a concentric connection with a latch.

Figures 2A and 2B display an example of a base in more detail, with a view from the top (Fig. 2A) and a view from the bottom (Fig. 2B). The base part 2 is provided with a drive 11 to allow low-frequency vibration of table 4. In this example, the base part is provided with small elastic feet 12 that serve as vibration absorbers that rest on the bottom of the base. This type of construction shows four small feet, other types of constructions may have more small feet. It has turned out, for instance, that a fifth foot at the centre line opposite the cord outlet (position south-east) has a favorable effect on the reduction of vibrations. Drive 11 makes table 4 vibrate, which table 4 is accessible at the top of base 2 on which the detachable bucket 3, in which the washing process takes effect, can be placed. The bucket, as far as shape and dimensions are concerned, is preferably comparable to a household bucket, with the advantage of a large and easily accessible opening. Filling, respectively emptying the bucket can be performed in the customary way, which is very handy. In the process, the entire washing device does not have to be lifted at all. It is possible to use more than one bucket alternately. For a short washing time, preheated liquid solution can be used. The buckets are easy to clean.

Figure 3 illustrates an exploded view of a table 4 with screw thread 7. The pitch angle of the screw thread lies preferably between 3 and 7 degrees, most preferably between 4 and 5 degrees. With a smaller pitch angle the force, necessary to screw the bucket tightly or loose, may increase to such an extent that it becomes difficult to screw the bucket tightly to and loose from the table. With a larger pitch angle there is a chance that the bucket, during vibration, is loosened from the table. In this example the table is provided with a groove 4a for an O-ring. The O-ring, not shown here, forms an elastic element between the bucket and the table. This avoids the bucket from being screwed too tightly to the table and ensures a better mechanical transmission of the vibration of the table to the bucket. The O-ring also reduces any possible clearance between the table and the bucket.

Figure 4 illustrates a drive 11. In this illustration the drive is furnished with power supply 12. The power supply to the washing device may come from either the electric mains or by means of batteries that can be rechargeable or by means of a connection to, for instance, an (automobile) battery. In this example the drive 11 is equipped with a frame 13 that pivots around a hinge 14. The drive is supplied with a table holder 15 that supports table 4.

The drive in the preferred embodiment shown in Figure 4 is provided with a frame with two parallel-arranged shafts 16, which preferably are embedded in ball bearings, roller bearings or slide bearings and an electric motor. On both sides the two shafts are furnished with eccentric weights. A gear wheel is mounted on both shafts as well as on the motor with the objective to have the eccentric weights rotate in opposite directions. Of the three gear wheels, at least the middle one can be equipped with "synchromesh rings" on both edges to avert (the chance of) rattling. The vibration frequency can be determined by choosing the appropriate speed. This manner of generating low-frequency vibrations results in a very attractive rate of efficiency, to wit > 75%. An additional advantage of using two shafts which rotate in opposite directions is that the base is less likely to shift, at least there is a lesser chance of the base shifting around than would be the case when using a single shaft. In this respect, the rotation of the shafts in opposite direction provides a stabilizing effect. This is particularly important for those types of constructions of the washing device according to the invention, in which the washing device is equipped with a loose base part. With a built-in base part, there is much less probability of the base shifting and it can be advantageous to use a single shaft.

The end of the frame for the drive, for instance, is provided with a shaft which can rotate in two slide bearings. The slide bearings are embedded in a block that constitutes part of, or is rigidly fastened to a mounting plate, or is fastened to a mounting plate by means of a vibration/noise absorber, which mounting plate in turn constitutes part of, or is rigidly fastened to the base part of the device.

Figure 5 illustrates a detail of the structure. Preferably the drive is fastened to the device by means of a hinged guide 14 in such a way that the table holder 15 can make a small arc-shaped movement T in nearly vertical direction. The table holder 15 is furnished with spacers and connection elements 17 on which table 4 (not shown in Figure 5) is positioned and attached. To now prevent that the rigidly connected, moving parts consisting of the drive, table 4 and bucket 3 with contents, do not move downward unwantedly as a result of gravity, the moving force on this structure is compensated by a spring structure so that the unit remains balanced and in fact assumes a floating position. The spring structure consists of one or more metal coil springs or of one or more rubber springs, in Figure 5 the springs are marked with a V. Figure 5 also schematically illustrates that the shafts 16a and 16b, to which eccentrics are connected, rotate in opposite directions (in Figure 5 schematically marked with the curved arrows).

The combination of the drive and this structure allows for a very low and very compact mode of construction.

In another embodiment the guide is constituted by one or more leaf springs. These leaf springs are embedded into a block that constitutes part of, or is rigidly fastened to a mounting plate, or by means of a vibration/noise absorber is fastened to a mounting plate, which mounting plate in turn constitutes part of, or is rigidly fastened to the base part of the device.

In still another embodiment the guide is constituted by two so-called "silent blocks". These "silent blocks" are embedded into a block that constitutes part of, or is rigidly fastened to a mounting, or by means of a vibration/noise absorber is fastened to a mounting plate, which mounting plate in turn constitutes part of, or is rigidly fastened to the base part of the device.

Under no-load condition, thus without bucket or bucket without contents, the frame with table, owing to the spring construction, can be held against a top travel stop that is formed by the material of the base or by a part that is rigidly fastened to it. Under an overloaded condition, the excess mass ensures that the bottom travel stop is reached, which is formed by a part rigidly fastened to the base; however, arranged in in opposite direction. The spring structure referred to has preferably been dimensioned in such a way that the position, with a disparity in mass, resulting from more or less liquid solution including laundry, is compensated as well.

As soon as one of the travel stops has been reached in the event of too little load, overload, excessive misalignment or insufficient quality of the bottom or worktop, the drive preferably is configured such that in that case the drive of the washing device will be switched off.

If the masses of the eccentric weights are equal or approximately equal to each other and these are fastened symmetrically or approximately symmetrically relative to each other, the amplitude of the table will be at a maximum and the waveform of the movement will, in essence, be rectilinear, perpendicular on the surface through the shafts while also no undesirably resultant side-thrusts are released towards the outside, which results in more stability. As the mass of the eccentric weights becomes bigger, the amplitude will increase. If the eccentric weights between the shafts themselves differ in mass, the waveform of the movement will be circular-shaped or at any rate be arc-shaped. If the symmetry is deviated from, the degree of amplitude will change. The washing effectiveness can be influenced with these variants.

In yet another embodiment of the drive this comprises a "voice coil", functioning in a strong magnetic field. In that case the guide consists of a parallelogram of, for instance, circular-shaped leaf springs. In this embodiment the table makes a straight vertical movement.

Figure 6 illustrates a bucket that can advantageously be used for or in a washing device according to the invention. The bucket is designed in a bell beaker shape. The shape is somewhat more rigid than the customary straight bucket shape. The higher rigidity of the bucket has a positive effect on the efficiency with which the vibrations of the table are converted into vibrations in the liquid solution. Also Figure 6 illustrates that the bottom of the bucket can be supplied with an element 18 for a bayonet fitting.

Figure 7 illustrates a further example of a base part 2 with drive 11 of or for a washing device in accordance with the invention. In this embodiment the base comprises a hand grip 19, with which the base, with or without bucket, can be lifted and/or transported. The handgrip 19 can also serve as a carrier for accessories, such as a wringer at an extremity 19a of the hand grip. During transportation this hand grip 19 is collapsible therefore occupying little space. The hand grip 19 is preferably safeguarded against undesirable hinged movements by means of a self-closing lock. The bucket can be stored, respectively taken along separately or together with other buckets.

Figure 7 also illustrates that the table 4 in this example slightly protrudes at the top and is positioned in a floating manner in relation to top blade 20 of the base 2. This means that the detachable bucket can easily be fastened to the table.

Figure 8 illustrates schematically a washing device in operation. On the table 4 a bucket is attached by means of, for instance, screw threads 6 and 7 on or to the table and the bucket. Drive 11, in this example provided with a single rotating shaft in a bearing housing, causes the table to vibrate T. The table and bucket vibrate jointly. The vibration T is transmitted to the liquid solution in the bucket. This is schematically illustrated by the waves in the liquid solution in the bucket.

Figure 9 illustrates a base part suitable for installation into, for instance, a boat or vehicle. The base part is equipped with a collapsible platform 91. When built-in, the platform is folded down and in this way can serve as a table top, (kitchen) sink top or windowsill. If the users want to use the washing device, the platform 91 is swung open, bucket 3 screwed on the table or fastened otherwise and the washing device is ready for use. The base of the washing device is hidden, for instance, under a windowsill or table top or under a cover of a storage area and therefore takes up practically no living space. Particularly boats and vehicles with a room for living or living quarters such as caravans, campers, small-sized motor and sail boats have too little space for a conventional washing machine which furthermore, while in operation, requires too much water for the customary water tanks used in such boats and vehicles, so that the users of such boats and vehicles for the purpose of washing laundry have to resort to launderettes and suchlike which sometimes are not on hand and such visits, in any event, demand much precious time. In these circumstances, the washing device according to the invention comes to the rescue. The platform 91 can be positioned in such a way that when it is folded down it is situated slightly above the table, so that the table is not visible, or the platform can be fitted with an opening, so that when it is folded down, the table is accessible, and the table is either flush with the platform or it protrudes above the platform.

Figure 10 illustrates schematically a traditional washing machine, namely a washing machine known from the patent specification UK875,201. The prior art washing machine contains a housing 101 made of one piece construction. A rubber interior drum 102 is fastened in the housing 101. In the housing 101, underneath the rubber interior drum 102, and firmly connected to the rubber interior drum 102, a vibration unit 103 is situated, which makes the rubber interior drum 102 vibrate. Here, however, there is no evidence of a bucket that can be detachably connected by the user. The entity can perhaps be dismantled in parts by a certified mechanic with ample know-how and expertise or by using brute force, but it will be obvious that this is not understood to mean detachably connected within the context of the invention.

The rubber interior drum of the traditional washing machine is firmly connected at the bottom and top, at the bottom firmly connected to the vibrating element 103 by means of a metal plate encased in the bottom of the rubber interior drum, and connected with screws to the vibration unit and at the top with the housing 101. In such a washing machine the interior drum is wholly or partly made of flexible material and fastened to both vibrating element 103 and the housing 101. With such type of construction the vibrations generated by the vibrating element 103 are at least partly suppressed by the rubber interior drum 102, and much of the energy supplied is converted into vibrations of the flexible interior drum, not into vibrations in the water in the interior drum. Therefore the efficiency is low. Furthermore, the user does not have the possibility to use several buckets or to simply exchange or clean a dirty bucket. Other patent specifications that display similar washing machines are, among others, US 2,203,479, SU 1663074, BE 570540, FR 1,032,872. In these patent specifications the washing device contains a drum, that is to say, a non-detachable, drum, that contains one or more flexible parts, to which parts a vibrating element is connected, in order to make the flexible part of the drum vibrate. The connection between the vibrating element and the flexible parts of the drum is secured, internally in the apparatus and therefore not detachable by the user. In the invention the bucket is detachable, which means by the user detachable couplings, connected to the table and the table vibrates the bucket as a whole, by which the vibrations of the bucket are not or much less suppressed. Furthermore, flexible parts have the tendency to start leaking quickly.

Within the context of the invention it shall be obvious that many variations are possible and that the invention is not limited to the above-mentioned examples.

For instance: the shape of the bucket can vary, the coupling facilities can vary.

It is possible to provide the laundry washing machine with sensors to control the amplitude, movement and/or frequency of the table, either with or without the dependency of the parameter of the bucket. For instance: the weight of the bucket, filled with liquid solution and laundry, can be measured. For this purpose the table can be furnished with strain gauges. Also the pressure of the springs V can be measured and be a measurement of the weight that is fastened on the table. The device can also contain a look-up chart, listing data showing a link between the weight and the required amplitude or frequency of the table.

The laundry washing machine can also contain sensors, for instance optical sensors, with which the amplitude and/or frequency of the table can be gauged. Deviations between a pre-set or desired amplitude and/or frequency can be gauged with these sensors and, if necessary or desired, adjusted accordingly.