Patent Description:
Such a washing machine is disclosed for instance in <CIT> where load cells are located in a frame in the bottom of the machine. Such load cells can be used to weigh the amount of laundry loaded into the drum, allowing the washing cycle to be adapted thereto.

One problem associated with washing machines of this type is how to make the machine capable of carrying out a more adaptable washing cycle that is more efficient.

<CIT> discloses a horizontal axis washing machine (<NUM>) comprising a body (<NUM>), a drum which is disposed inside the body (<NUM>), rotates in the horizontal axis and wherein items to be washed are placed, and a tub (<NUM>) wherein the drum rotates; and wherein the amount of water to counterbalance the unbalanced load and minimizeits effect is continuously delivered to the desired place in the case of an unbalanced load.

<CIT> discloses a washing machine (<NUM>) comprising a drum (<NUM>) which is disposed in the body (<NUM>) and rotates around the horizontal axis, and wherein items to be washed are placed, a tub (<NUM>) wherein the drum (<NUM>) moves and which oscillates together with the drum (<NUM>) during the operation, two support blocks (<NUM>) which extend in the body (<NUM>) from the front backwards oppositely in the horizontal direction at the bottom side of the drum (<NUM>) at its right and left sides, more than one shock absorber (<NUM>), one end of which is connected to the tub (<NUM>) and the other end to the support block (<NUM>) and which absorbs the vibration movements of the tub (<NUM>), more than one shock absorber pin (<NUM>) which connects the lower ends of the shock absorbers (<NUM>) to the support block (<NUM>), a lower frame (<NUM>) which is located at the bottom side of the body (<NUM>) and supported by the feet seated on the floor, and whereon the support blocks (<NUM>), are seated and which, together with the support blocks (<NUM>), supports the weight of the tub (<NUM>), of the drum (<NUM>) and of the drum (<NUM>) motor, and load sensors (<NUM>) which provide weight and unbalanced load detection to be performed.

<CIT> discloses a laundry machine (<NUM>) for treating laundry items. The laundry machine (<NUM>) comprises a cabinet (<NUM>) for accommodating components necessary for the operation of the laundry machine (<NUM>), a washing tub (<NUM>) comprising a rotatable drum for containing laundry items, the washing tub (<NUM>) being enclosed by the cabinet (<NUM>) such that it can be moved in a floating manner inside said cabinet, at least one suspension element (<NUM>) comprising a first portion (220a,111a; 320a,111a) associated to the cabinet (<NUM>) and a second portion (220b,111c; 111c) associated to the washing tub (<NUM>) for movably coupling the tub (<NUM>) with the cabinet (<NUM>) of the laundry machine (<NUM>), and a load sensing device (<NUM>; <NUM>) for measuring a physical value related to the weight of laundry items provided in the washing tub (<NUM>), wherein the load sensing device (<NUM>; <NUM>) comprises a device first member (<NUM>; <NUM>) comprising a first sensor element (<NUM>; <NUM>) and a device second member (<NUM>; <NUM>) comprising a second sensor element (235b; 335b). The load sensing device (<NUM>; <NUM>) is coupled with the at least one suspension element (<NUM>) with the device first member (<NUM>; <NUM>) associated to the first portion (220a,111a; 320a,111a) of said suspension element (<NUM>) and with the device second member (<NUM>; <NUM>) associated to the second portion (220b,111c; 111c) of the suspension element (<NUM>) or vice-versa. Thereby, the change of length of the suspension element (<NUM>) causes the change of distance between said first and the second sensor elements.

One object of the present invention is therefore to provide a washing machine with a load sensor that provides more versatile data.

This object is achieved by means of a washing machine as defined in claim <NUM>. More particularly, in a washing machine of the initially mentioned kind, there is provided a first structural element, which is connected to either of the housing and the suspension arrangement, and a second structural element which is connected to the other of the housing and the suspension arrangement. The first and second structural elements extend in first and second planes, respectively, which are mutually parallel. Further, the load sensing device, which may typically be a planar beam load cell, is attached to the second structural element on a surface thereof facing away from the first structural element and is connected to the first structural element.

This allows a very compact arrangement, as there is only needed a small gap between the first and second structural elements, which is bridged by the load sensor. The load sensing arrangement is nevertheless capable of measuring the load in between the drum and the suspension arrangement which provides improved load sensing data, which may be used for a more adaptive control of the washing machine.

The second structural element may comprise an opening, and the load sensing device may be connected to the first structural element through the opening. This allows the first and second structural elements to be connected to each other via the load sensing device, without the latter being mounted between the first and second structural elements.

The load sensing device may be attached to the second structural element by means of an attachment part such as an attachment plate, which is attached to the second structural element on a surface thereof facing towards the first structural element. This provides a firm attachment point on the second structural element even if this element consists of a relatively thin metal plate.

There may be provided an opening in the first structural element which at least partly accommodates the attachment part. This allows the first and second structural elements to be located very close to each other without the attachment part touching the first structural element. The attachment part may be positioned in a stamped recess in the second structural element to offset the load sensing device slightly from the remainder of the second structural element to facilitate the load sensing device's bending, slightly towards the latter.

There is provided three or more sensing devices in between the suspension arrangement and the drum.

The sensing device may be a planar beam load cell, although other load sensing devices are conceivable in this context.

There is provided a door for gaining access to the interior of the drum, and the door is suspended by the suspension arrangement. This may be achieved for instance by attaching the door to a housing, which contains the rotatable drum and is carried via the sensing arrangement. This means that no connections, by bellows or the like, between suspended and non-suspended parts are needed to arrange the door, which reduces disturbances on the load measuring.

The present disclosure relates generally to a washing machine <NUM>, an example of which is shown in <FIG>. The washing machine comprises an outer housing <NUM> and rests on a base structure <NUM>, which is typically a floor, but in principle could be a rack or another machine, for instance. At a front side <NUM> of the washing machine, there is located a door <NUM> through which the interior of a drum is accessible.

<FIG> shows a suspension arrangement carrying a rotatable drum <NUM> inside the housing <NUM> of <FIG>. The rotatable drum <NUM> is located inside a typically cylindrical housing <NUM>, which is carried by a drum cradle arrangement <NUM>, which in turn is carried by a suspension arrangement <NUM>, <NUM>, comprising dampers <NUM> and springs <NUM> connecting the cradle arrangement to a bottom part <NUM> of the machine that rests on the base structure/floor <NUM>. Typically, one damper/spring combination is used in each corner.

As illustrated, at delivery, the cradle arrangement <NUM> may be firmly connected to the bottom part <NUM> by means of transport lock plates <NUM>, which are removed before the washing machine is used.

Weights <NUM> may be added to the cradle arrangement to obtain suitable spring-mass system properties.

As shown, the door <NUM>, used for gaining access to the interior of the drum <NUM>, may be suspended by the suspension arrangement, i.e. is attached to the cylindrical housing <NUM> in which the rotatable drum <NUM> moves, rather than to the outer housing <NUM> of the machine. This means that there is one fewer part disturbing the collecting of load data, as will be described. If instead a door for instance would be attached to the outer housing <NUM> providing an opening that is connected to the cylindrical housing <NUM> by means of a bellow, that connection between a part suspended by the suspension arrangement and a non-suspended part would impair the load measurements as some load would be carried via the bellow rather than via the load sensors.

<FIG> shows a partially exploded view of a drum cradle in the suspension arrangement of <FIG>. As shown, there is on each side provided a first structural element <NUM> which is connected to the drum of the machine, which is kept in place by bands <NUM>. The first structural element <NUM> may as shown be in the form of a sheet metal plate, which substantially extends in a first plane in a first portion although it may be bent to form other parts of the cradle.

There is provided, as shown in the exploded view on the right side, a second structural element <NUM>, which is connected to the suspension arrangement (<NUM>, <NUM> cf. The second structural element <NUM> may as well be in the form of a sheet metal plate, and this plate may substantially extend in a second plane, which is parallel with the first plane, i.e. the plane of the first structural element <NUM>, at a location where they are interconnected as will be shown.

The first and second structural elements <NUM>, <NUM> are interconnected by means of load sensors <NUM> that together sense the load on the drum. There is thus provided a gap between the first and second structural elements <NUM>, <NUM> which is bridged by the load sensors <NUM>. Typically, three or more such load sensors <NUM> are used, in the illustrated case four arranged in corners of a rectangle as seen from the top of the washing machine.

As this sensing is done on the drum's <NUM> side of the suspension arrangement <NUM>, <NUM>, more information about the drum's dynamic load is included in the obtained data as this is not blurred by an intervening suspension arrangement. This allows the machine of being very precisely controlled for instance during a centrifuge process to achieve improved operation.

<FIG> show enlarged portions A, B, and C of <FIG>. To start with, the arrangement used to attach the load sensor <NUM> to the second structural element <NUM> is shown in <FIG>. The second structural element <NUM> comprises an opening in the form of a hole <NUM>, through which the load sensor can connect to the first structural element <NUM>. In the illustrated case, the opening is a hole in the second structural element <NUM>, although in principle there could also be provided a cut-out from the edge of the first structural element <NUM> as indicated with dashed lines. In principle there could also be provided an arrangement that connects the load sensor to the first structural element around the side edge of the first structural element <NUM>. It should be noted though, that the illustrated embodiment with a hole <NUM> in the sheet metal plate forming the first structural element allows a both strong and compact connecting arrangement.

As the load sensor <NUM> will be required to take up significant loads it should be firmly connected to the second structural element <NUM>. In order to avoid using a thick sheet metal piece to form the second structural element <NUM>, there may be provided an attachment part e.g. in the form of an attachment plate <NUM> on the side of the second structural element which faces the first structural element. This allows the load sensor <NUM> to be firmly connected to the second structural element <NUM> without making the latter flex significantly at this point.

As shown in <FIG>, there may be arranged an opening <NUM> in the first structural element <NUM> which at least partly accommodates this attachment plate <NUM>. The opening <NUM> is slightly wider than the extensions of the plate to allow some movement between the structural elements. This arrangement allows the first and second structural elements <NUM>, <NUM> to be placed very close to each other without interfering with the measuring carried out by the load sensors. The attachment plate <NUM> may be attached to the second structural element <NUM> by means of a first set of bolts <NUM> or by means e.g. of welding, and the load sensor may in turn be attached to the attachment plate <NUM> by means of a second set of bolts, through the second structural element.

The load sensor, shown in <FIG>, may be a planar beam load cell <NUM>, and may comprise threaded openings <NUM> for the bolts <NUM>, indicated in <FIG> and connecting to the second structural element <NUM>, as well as an opening <NUM>, which by means of a bolt (<NUM>, cf. <FIG>) is connected to a nut and bolt configuration <NUM>, <NUM>, being firmly attached to the first structural element <NUM>. Other load sensors than planar beam load cells are conceivable in this context as is known to the skilled person, for instance a piezo electric cell could be located in between the first and second structural elements <NUM>, <NUM>.

<FIG> shows a cross-section through the suspension arrangement <NUM>, <NUM> as illustrated in <FIG> and as seen from the side of the washing machine.

<FIG> shows enlarged the portion D of <FIG>, which illustrates a load sensor <NUM> in the form of a planar load cell connecting a first structural element <NUM>, in the form of a sheet metal plate, to a second structural element <NUM>, also in the form of a sheet metal plate. As shown, the load sensor <NUM> is attached to the second structural element <NUM> by means of an attachment plate <NUM> on the opposite side of the second structural element <NUM>. There may be formed a stamped recess <NUM> in the plate forming the second structural element <NUM> at the location of the attachment plate <NUM> such that the load sensor <NUM> is slightly offset from the second structural element <NUM>, except where attached thereto. This allows the load sensor to flex towards the second structural element <NUM> even if being flat. This offset could also be achieved also with another attachment plate, on the load sensor's side.

The attachment plate <NUM> is screwed to the second structural element <NUM> by means of bolts <NUM>, and the load sensor <NUM> is attached, at one end, to the attachment plate <NUM> and the structural element by means of another set of bolts <NUM>. As can be seen, the attachment plate <NUM> reaches into an opening <NUM> in the first structural element <NUM> to allow the structural elements to be placed closer to one another. This opening <NUM> is slightly bigger than the plate <NUM>, such that that the latter can move slightly without touching the first structural element <NUM>.

The other end of the load sensor <NUM> is connected to a bolt and screw combination <NUM>, <NUM>, which is attached to the first structural element <NUM> by clasping the rim of an opening therein. The load sensor <NUM> is attached thereto by means of a bolt <NUM> which is screwed into a threaded opening in the bolt <NUM> attached to the first structural element <NUM>.

<FIG> schematically shows a washing machine having load sensors arranged on the drum's side of a suspension arrangement. Thus, in a laundry washing machine comprising a rotatable drum <NUM>, a suspension arrangement <NUM>, <NUM> carries the drum in relation to a base structure <NUM> located under the washing machine on which the washing machine rests. A load sensing device <NUM>, configured to sense the load of the drum <NUM> is provided. The load sensing device <NUM> is located on the opposite side of the suspension arrangement <NUM>, <NUM> as seen from the base structure <NUM>.

Claim 1:
A laundry washing machine (<NUM>) comprising a rotatable drum (<NUM>) inside a housing (<NUM>), a suspension arrangement (<NUM>, <NUM>) carrying the housing (<NUM>) in relation to a base structure, located under the washing machine and on which the washing machine (<NUM>) is adapted to rest, and a load sensing device (<NUM>), configured to sense the load of the drum (<NUM>); characterized by:
a first structural element (<NUM>) substantially extending in a first plane and being connected to either of the housing (<NUM>) and the suspension arrangement (<NUM>, <NUM>), and
a second structural element (<NUM>) substantially extending in a second plane, which is parallel with the first plane, and being connected to the other of the housing (<NUM>) and the suspension arrangement (<NUM>, <NUM>),
wherein the load sensing device (<NUM>) is attached to the second structural element (<NUM>) on a surface thereof facing away from the first structural element (<NUM>) and is connected to the first structural element (<NUM>).