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Title:
LAUNDRY TREATMENT APPLIANCE WITH WEIGHT SENSOR
Document Type and Number:
WIPO Patent Application WO/2019/204948
Kind Code:
A1
Abstract:
The laundry treatment appliance comprises a container (2) suspended from a support (20). The support (20) rests on two bars (17) of a frame (15). At least one deformation sensor (22) is mounted to at least one of the bars (17) in order to measure the deformation of the bar(s). This provides for an accurate measurement of the weight of the container (2).

Inventors:
SIBAK MARTIN (CH)
GÜDEL DANIEL (CH)
Application Number:
PCT/CH2018/000019
Publication Date:
October 31, 2019
Filing Date:
April 27, 2018
Export Citation:
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Assignee:
V ZUG AG (CH)
International Classes:
D06F34/18; D06F58/38
Domestic Patent References:
WO2012089442A12012-07-05
Foreign References:
EP3269866A12018-01-17
EP1953291A12008-08-06
DE2034847A11972-01-27
Other References:
None
Attorney, Agent or Firm:
E. BLUM & CO. AG (CH)
Download PDF:
Claims:
Claims

1. A laundry treatment appliance, in particular a washing machine, comprising

a frame (15) ,

a plurality of feet (16) mounted to and supporting said frame (15) ,

a container (2 ) for receiving laundry to be treated,

a support (20) supporting a weight of said container (2) ,

a weight sensor adapted to. weigh said con- tainer (2) ,

wherein said frame (15) comprises at least one bar ( 17 ) suspended between two of said feet ( 16) , wherein said support (20) rests on said bar

(17) ,

and wherein said weight sensor comprises a deformation sensor (22) measuring a deformation of said bar ( 17 ) .

2. The appliance of claim 1 wherein said sup- port (20) comprises a support member (20) having a head section (24 ) extending over said container (2) and two leg sections (21) arranged on opposite sides of said container (2) , wherein each of said leg sections (21) rests on said frame (15) , wherein said appliance further com- prises at least one spring member extending between said support member (20 ) and said container (2) .

3. The appliance of claim 2 wherein said frame (15) comprises at least two bars (17) , with each bar (17) supporting one of said leg sections (21).

4. The appliance of claim 3 comprising a deformation sensor (22 ) for each of said two bars (17 ) .

5. The appliance of any of the preceding claims further comprising at least one dam ing member ( 28 ) extending between said container (2) and said bar (17).

6. The appliance of any of the claims 3 or 4 and of claim 5 wherein said appliance comprises at least two damping members (28) , with each of said two bars (17 ) supporting at least one of said damping members (28 ] .

7. The appliance of any of the preceding claims wherein said deformation sensor (22) comprises a strain gauge mounted to said bar (17) .

8. The appliance of claim 7 , wherein said support (20) contacts said bar (17) in a contact region ( 305 and wherein said strain gauge extends over at least one edge ( 31 ) of said contact region (30) .

9. The appliance of one of the claims 5 or 6 and of claim 8, wherein said damping members (28) is con- nected to said bar ( 17 ) in said contact region (30) .

10. The appliance of any of the preceding .claims wherein said support (20) rests on a center (33) of said bar (17 ) between said two feet (16) .

11. The appliance of any of the preceding claims wherein said support ( 20 ) contacts said bar (17 ) in a contact region (30) and wherein an extension (W) of said contact .region (30) along a direction between said two feet (16) is smaller than 25% of a distance (L) be tween said two feet (16) .

12. The appliance of any of the preceding claims further comprising a housing { 1) , wherein a weight of said housing is supported by said feet (16) without resting on said bar ( 17 ) between said feet (16).

13. The appliance of any of the preceding claims further comprising a control unit (12) adapted to measure a signal from said deformation sensor (22) and adapted to use said signal for at least one of

- estimating a weight of said laundry,

- estimating an amount of water within said container (2),

- estimating an imbalance of a rotating drum of said container (2),

- estimating a loss of water in said laundry while drying said laundry,

- controlling an amount of water fed to said container (2) ,

- calibrating said deformation sensor (22) by feeding a known amount of water to said container (2) .

14. The appliance of any of the preceding claims wherein said container (2) comprises drum (4) ro tatable about a horizontal axis (5) of rotation.

15. The appliance of claim 14 wherein said drum (4) is rotatably arranged in a tub (3).

16. The appliance of any of the preceding claims wherein said frame (15) is located at a level below said container (2 ) .

17. The appliance of any of the preceding claims wherein said appliance is a washing machine and/or wherein said appliance is a laundry dryer.

Description:
Laundry treatment appliance with weight sensor

Technical Field

The invention relates to a laundry treatment appliance, in particular to a washing machine or a washer-dryer .

Background Art

Laundry treatment appliances, such as laundry machines and/or laundry dryers, can comprise a weight sen- sor for measuring the weight of the laundry container . This allows to e. g. determine the amount of laundry to be washed or the amount of water in the container.

Typically, the weight is measured at the sus pension of the container, such as at a spring member from which the container is suspended. This approach, however, is complicated, and it does not provide good accuracy, in particular if the container is also equipped with damping elements, which tend to affect such measurements due - their slip/stick behavior.

Disclosure of the Invention

The problem to be solved by the present invention is to provide a laundry treatment appliance, in particular a washing machine, of the type mentioned above that has an accurate but economic weight sensor .

This problem is solved by the laundry treat ment appliance of claim 1.

Accordingly, the laundry treatment appliance comprises the following elements :

- A frame: This is a stationary structure within the appliance . - A plurality of feet : The feet are mounted to the frame and support it e.g. against a floor or shelf below the appliance.

- A container: The container is the part receiving the laundry to be treated. It can e.g. comprise the tub and the drum of a washing machine or the tub of a laundry dryer.

- A support: The support is a stationary structure of the appliance, and it supports the weight of the container. In particular, it supports at least 80%, in particular at least 90% of the weight of the con tainer .

- A weight sensor : This sensor is adapted to weigh the container.

According to the invention, the frame com prises at least one bar suspended between two of the feet, and the support rests on the bar . Hence, the weight is received by the bar and generates a deformation in the bar. The weight sensor comprises a deformation sensor for measuring this deformation .

This design allows to measure the weight of the container at a location other than a suspension spring member and using a simple deformation sensor for the purpose .

In one embodiment , the support comprises a support member havin a head section extending over the container and two leg sections arranged on opposite sides of the container. Each of said leg sections rests on the frame . In other words, the support member extends over the container, e.g. in the shape of an inverted "U". The appliance further comprises at least one spring member extending between the support member and the container. This at least one elastic spring member can support at least part of the weight of the container. Advanta geously, the spring member or spring members support at least 80%, in particular at least 90%, of the weight of the container. In this case, the frame can comprise at least two bars. Each bar supports one of the leg sections. In particular, there can be a. deformation sensor· arranged at each bar. Alternatively, there can be a deformation sensor arranged at only one of the bars because, typically, the weight of the container is equally distributed be tween the bars .

In addition, the appliance can comprise at least one damping member adapted to dampen oscillations of the container . For example, a non-elastic, frictional damping member can be used. This damping member extends between the container and the bar, such that any weightof the container that is borne by the damping member also adds to the deformation of the bar, thereby rendering the measurement more accurate .

In particular, the appliance comprises at least two such damping members, with each of the two bars supporting at least one of the damping members.

In one embodiment, the weight sensor can comprise a strain gauge mounted to said bar . Such a strain gauge is a simple and economic means for measuring the bar's deformation.

Advantageously, the support rests on the cen ter of said bar between said two feet . In this context, "resting on the center" means that the distance between the center of the part of the support contacting the bar and the center of the bar between the feet is smaller than 25% of the distance between the feet .

The present invention is particularly suited for appliances where the container has a drum that can be rotated about a horizontal axis of rotation.

The appliance is preferably a household ap pliance .

It can e.g. be a washing machine and/or a laundry dryer . It can also be a washer-dryer, i.e. a machine that is both a laundry machine and a laundry dryer. Brief Description of the Drawings

The invention will be better understood and 5 objects other than those set forth above will become ap parent when consideration is given to the following detailed description thereof . This description makes reference to the annexed drawings, wherein:

Fig. 1 shows a schematic, sectional view of a xo washer-dryer,

Fig . 2 shows a view of a specific embodiment of a washer driver,

Fig. 3 shows a side view of the appliance of

Fig. 2,

is Fig. 4 shows a detail of Fig. 3,

Fig. 5 shows a front view of the appliance of

Fig. 2. 0

Modes for Carrying Out the Invention

General :

Fig . 1 shows a washer-dryer having a housing5 · 1. A container 2 for receiving the laundry is arranged in housing 1. Container 2 e . g . comprises a tub 3 and a drum

4.

Drum 4 can be rotated about an axis of rota tion 5. Axis of rotation 5 is advantageously horizontal,0 i . e . its deviation from a horizontal direction is less than 10°.

In a washer-dryer, drum 4 is e.g. mounted to tub 3 by means of a rotational bearing 6. A drive 7 is provided for rotating drum 4.

5 Drum 4 has a front end with an opening 8. It faces a door 9 of the appliance . Since the appliance is a washer-dryer, it comprises a drying and heating unit for drying and heat ing process air. This drying and heating unit is schematically shown in Fig. 1 under reference number 11.

The appliance further comprises a control unit 12 for controlling the various elements of the appliance, for taking measurements, and for interacting with the user . Control unit 12 can e.g. comprise a micro processor programmed to carry out the steps for operating the appliance .

The appliance further comprises a frame 15 and a plurality of feet 16.

Frame 15 comprises at least one bar 17 sus pended between two of the feet 16.

Frame 15 is advantageously arranged at a bottom of the appliance, at a level lower than the lowest part of container 2.

Container 2 is held by a support 20, which is e.g. designed as a structure having the shape of an in- verted "U" extending over container 2 and having two vertically-extending leg sections 21, each of which is resting on one of the bars 17 of frame 15.

Container 2 is e.g.. suspended within support 20, e.g. by means of one or more spring members {not shown in Fig . 1)

Hence, the weight (or a substantial part thereof) of container 2 and its contents rests on the bars 17. Hence, the bars 17 will be deformed, as a func tion of said weight .

A strain gauge or another type of deformation sensor 22 is provided for measuring this deformation .

Control unit 12 receives the signal from deformation sensor 22 and uses it measure the weight , or a quantity depending on the weight, of container 2.

As can be seen from Fig . 1, the feet 16 are directly connected to housing 1. In other words , the weight of housing 1 is directly borne by the feet . It is not borne by the bars 17, in particular by the part of the bars 17 that receive the weight from support 15, i . e . the weight of the housing 1 does not deform the bars 17 at the location of deformation sensor 22. This allows to obtain more accurate measurements .

Mechanical design :

An example of the mechanical design of such an appliance is shown in Figs 2 - 5, which show the ap pliance with only part of housing 1.

As can be seen, frame 15 can e.g. be formed by two lateral bars 17 and two transversal bars 17' , which are arranged at right angles to each othe . The bars 17 , 17' are suspended between the feet 16,

The bars are advantageously of metal, in particular steel .

Support 20 has a head section 24 that extends over container 2. Advantageously, it extends transver- sally, in particular perpendicularly, to the axis of ro tation 5

Head section 24 is supported, . on both sides of container 2, by the leg sections 21.

The bottom ends of the leg sections 21 rest on the bars 17 of frame 15. Advantageously, they are fix edly connected thereto, e.g. by means of brackets or flanges 25.

The deformation sensor 22 is best seen in Fig. 4. It is e.g. a strain gauge mounted to bar 17. It changes its electrical resistance as a function of the deformation of Fig. 17. Advantageously, it is mounted to the bottom side of bar 17.

In the embodiment of Figs . 2 - 5, container 2 is suspended from support 15 by means of two or morespring members 27. The spring members extend between support 15 and container 2.

In addition, the shown appliance comprises two or more friction-based damping elements 28. Each damping element 28 extends between container 2 and one of the bars 17.

Design considerations :

The bars 17 can be dimensioned such that, under the variation of the weight of a full and an empty container 2, they deform in such a manner that the- deformation can be measured by means of deformation sensor 22.

In order to make the deformations easy to measure, the location where the weight of container 2 is guided into bar 17 should be far from the feet 16, advan tageously at least 50 mm.

As illustrated in Fig. 1, where reference number 30 designates the contact region where support 15, in particular leg section 21, contacts bar 17. It has, in the direction extending between the feet 16 supporting bar 17 , an extension W.

Deformation of bar 17 will be strongest at the edges 31 of contact region 30. Hence, deformation sensor 22 should advantageously extend over at least one of the edges 31.

Further, as mentioned, support 15, in partic ular leg section 21 , should rest on the center of bar 17. In this context, "resting on the center" means that the distance D between the center 32 of the part 21 of sup port 15 contacting bar 17 and the center 33 of bar 17 be tween the feet 16 is smaller than 25% of the distance L between the feet 16.

Another important parameter is the extension W as compared to the distance L . In order to obtain strong deformations, W should be much smaller than L. In particular, W is advantageously no more than 25% of L.

Advantageously, the damping elements 28 are connected to bar 17 in the contact region 30 in order to feed any weight they might bear to the same location as support 15. Applications:

Control unit 12 can use the signal from de formation sensor 22 for a number of applications, such as :

- Estimating the weight of the laundry: For example, when the user fills in the laundry, the change of the signal from sensor 22 is a measure of the weight of the added laundry.

- Estimating the amount of water within con- tainer 2 : When control unit 22 fills water into container

3 , the container' s weight will increase . The change of the signal from sensor 22 is a measure of the amount of water filled into container 2. In particular, the signal of sensor 22 can be used for controlling the amount of water fed to container 2.

- Estimating the imbalance of the rotating drum 4 : During rotation, in particular during centrifuga tion (spinning) of the laundry, a strong imbalance will lead to periodic deformations of the bars 17 , which can again be measured by means of the signal of sensor 22.

- Estimating the loss of water in the laundry while drying the laundry: When drying the laundry, water is extracted from the laundry and the weight of container 2 decreases . The signal from sensor 22 is therefore a measure of the drying process . For example, early in a drying process, water can be extracted at a high rate and the signal from sensor 22 will therefore change quickly. However, once that the laundry is almost dry, the signal from sensor 22 will change more slowly. Hence, the signal from sensor 22 can e.g. be used for determining the drying state of the- laundry and, in particular, for stopping the drying process.

Calibration:

Control unit 12 can also be: adapted to calibrate sensor 22, For this purpose, control unit 12 feeds a known amount of water into container 2 and monitors the change of the signal from sensor 22. Using that change and the ( known) weight of the added water, sensor 22 can be calibrated, i.e. control unit 12 can calculate the change of signal per weight .

In order to control the amount of water fed to container 2, container 2 can e.g. comprise a water level sensor that generates a signal once the level of the water in container 2 reaches a certain level .

Notes :

While the above description shows washer-dryers, the invention can also be implemented in an appli ance that has only washing functionality or only drying functionality.

While there are shown and described presently preferred embodiments of the invention, it is to be dis tinctly understood that the invention is not limited thereto but may be otherwise variously embodied and prac- ticed within the scope of the following claims .