EP1953291B1

EP1953291B1 - Laundry treating machine with weight sensing means

Info

Publication number: EP1953291B1
Application number: EP07101440A
Authority: EP
Inventors: Andrei Uhov
Original assignee: Electrolux Home Products Corp NV
Current assignee: Electrolux Home Products Corp NV
Priority date: 2007-01-30
Filing date: 2007-01-30
Publication date: 2010-04-28
Anticipated expiration: 2027-01-30
Also published as: ES2343904T3; EP1953291A1; RU2008103369A; AT466127T; DE602007006148D1; PL1953291T3; RU2433215C2

Description

The present invention relates to a laundry treating machine such as a washing machine, a dryer or a washer-dryer, provided with weight sensing means.
It is known in the art of laundry treating machine to measure the weight of articles to be treated to adapt a treating program chosen by a user to real condition of articles stored within the treating chamber. For example, weight of wet laundry can be used to change the number of revolution per minute of a rotating drum in a drying machine to obtain laundry properly dried. In a washing machine, a laundry weight measure can be useful for determining the most appropriate amount of detergent and /or water to be used for washing laundry efficiently.
Many solutions have been proposed for measuring articles weight in a laundry treating machine. European Patent Application No. EP 1 258 556 discloses sensing means integrated in friction shock absorbers for detecting any drift/excursion in one or more of their spring elements. Such embodiment is however rather complex to be produced and requires to disassemble the whole machine in case of sensing means break. The latter drawback is due to the fact that the laundry treating chamber is suspended on said friction shock absorbers and therefore every intervention on them requires the treating chamber to be extracted from the machine.
An example of a laundry treating machine with the features of the preamble is disclosed in US-A-6460381 .
A further embodiment for measuring articles weight in a laundry treating machine is disclosed in European Patent Application No. EP 0 051 491 . In this document pressure responsive transducers are arranged between shock absorbers and a base portion of the cabinet. Such solution has the same drawbacks mentioned above for the EP 1 258 556 disclosure.
In the European Patent Application No. EP 1 110 499 strain gauges are proposed as electromechanical transducers for measuring weight of dishes in a dishwasher. Even if strain gauges may be arranged on machine supporting feet, i.e. in a place easy to be reached for a prompt substitution in case of break of a transducer, it must be noted that a strain gauge requires particular care and precision when it is installed and therefore complex assembling operations are required to produce the dishwasher or for performing maintenance interventions on it.
The aim of the present invention is therefore to solve the noted problems and thus providing a laundry treating machine having weight sensing means easy to be manufactured and ensuring a high reliability.
Another object of the present invention is to provide a laundry treating machine with weight sensing means that are easy to be installed and substituted in case of break without requiring machine cabinet disassembling operations.
Still another object of the present invention is to provide weight sensing means that can be installed in an already existing laundry treating machine with minimal modifications.
Advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realised and attained as particularly pointed out in the appended claims.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate a possible embodiment of the invention and together with the description serve to explain the principles of the invention.
In the drawings:
Figure 1 schematically shows a laundry treating machine according to the invention provided with weight sensing means;
Figure 2 shows an enlarged view of weight sensing means of figure 1;
Figure 3 shows a second embodiment of weight sensing means applicable to the laundry treating machine of figure 1;
With reference to figure 1, a laundry treating machine such as a washing machine, a dryer or a washer-dryer, comprises a cabinet 1 within which a treating chamber 2 is enclosed. Articles to be treated are placed into the treating chamber 2, such as a rotating drum, through an aperture 3 closed by a door. Foot members 4 are provided on a cabinet 1 outer base portion 5 for supporting the machine. Foot members 4 are threadly coupled to the base portion 5 to vertically modify the position of cabinet 1 in order to obtain proper horizontal adjustment.
Weight sensing means 6 are provided between cabinet 1 and one or more foot elements 4 for measuring weight of laundry contained in the treating chamber 2. With reference to figure 2, weight sensing means 6 comprise a couple of parallel, electrically conductive and spaced apart arms 7, 8 protruding from a transversal member 9 that joins them. Arms 7, 8 facing one another, define a clearance 10 between them and together with a transversal member 9 substantially form a "C" shaped structure working as a flat spring under the effect of machine and/or laundry weight.
First arm 7 has a hole for threadly receiving a foot element 4 and second arm 8 is associated in a known manner to the machine cabinet 1. A detector 11 is placed within the clearance 10 for detecting a change of weight due, for example, to progressive laundry drying or to laundry loading/unloading operations.
When a weight variation occurs in articles to be treated inside chamber 2, arms 7, 8 change their relative position altering the distance between them, i.e. changing the clearance 10 dimension. Such change modifies the dielectric layer (in this case an air layer) between arms 7, 8.
Detector 11 comprises a measuring electrode 13 placed within the clearance 10, said electrode 13 is associated to the arm 8 interposing a layer of electrical insulating material. Arm 7 is polarized to a ground potential and together with measuring electrode 13 define a capacitor. Detector 11 is suitable for measuring capacitance change between arms 7, 8 by outputting signals corresponding to laundry weight change inside the chamber 2. The method for measuring said capacitance change is known per sè, for example a suitable method for carrying out such measurement is described in the pending European Patent Application No. EP 06 114 827.6 . Signals emitted by detector 11 are sent to a microcomputer (not shown in figures) via a wire 12 and they are used for adapting machine working operations in function of the laundry weight. For example, in a dryer, laundry load measure can be used for calculating the laundry humidity and consequently varying machine working parameters like temperature of drying air and/or number of revolutions per minute of the drum drying chamber. As further example, in clothes washing machine, laundry load can be used for calculating the most appropriate amount of detergent to be used, and/or for calculating whether a further spin cycle is needed.
Detector 11 can provide a weight measure both whether the treating chamber 2 contains laundry both whether it does not. In the latter case, measured weight corresponds to the whole machine weight when the chamber 2 is empty. Such a weight value can be taken as zero, i.e. as reference value, for measuring laundry weight after its introduction in the treating chamber 2. Laundry weight can be measured continuously during machine working operations, therefore treating cycles can be constantly monitored.
In figure 3 it is shown a second embodiment of weight sensing means 26 that can be provided between cabinet 1 and one or more foot elements 4 for measuring weight of laundry contained in the treating chamber 2.
Weight sensing means 26, similarly to what has been described with reference to figure 2, comprise a couple of parallel, electrically conductive and spaced apart arms 27, 28 protruding from a transversal member 29 that joins them. Arms 27, 28 facing one another, define a clearance 210 between them and together with the transversal member 29 substantially form a "C" shaped structure working as a flat spring under the effect of machine and/or laundry weight.
First arm 27 is divided in two portions 27a, 27b by an opening 220 extending from the transversal member 29 in a direction substantially perpendicular to said member 29. In this way, portions 27a, 27b can move independently one another relatively to the second arm 28. Portions 27a and 27b form with the second arm 28 a couple of gaps 210a, 210b respectively.
One portion 27a of the first arm 27 has a hole for threadly receiving a foot element 4, while the other portion 27b has no support function for the machine but simply protrudes from transversal member 29. The second arm 28 is associated in a known manner to the machine cabinet 1.
A detector 211 is placed within the clearance 10 for detecting a change of weight due, for example, to progressive laundry drying or to laundry loading/unloading operations. In particular detector 211 comprises a couple of electrodes 213a and 213b associated to arm 28 in correspondence of gaps 210a and 210b respectively. Electrodes 213a and 213b are electrically isolated from arm 28. Portions 27a and 27b are polarized to a ground potential and together with electrodes 213a and 213b form two capacitors. When a weight variation occurs in articles to be treated inside chamber 2, portion 27a and arm 28 change their relative position altering the distance D_a between them, i.e. changing the dimension of gap 210a. Such change modifies the dielectric layer (in this case an air layer) between portion 27a and arm 28. Distance D_b between portion 27b and arm 28 remains substantially unchanged during weight variation and therefore the capacitance measured by electrode 213b in gap 210b can be used as reference value for compensating errors in measurement of capacitance change provided by measuring electrode 213a in gap 210a due to environment conditions like electromagnetic fields and air moisture.
Conclusively it can be stated that a laundry treating machine provided with weight sensing means according to the present invention is easy to be manufactured and allows the user to perform laundry treatments of improved quality. The same machine can be produced with minimal modification starting from an already existing laundry machine. Interventions in case of weight sensing means break are advantageously simplified.

Claims

Laundry treating machine comprising a cabinet (1) enclosing a treating chamber (2) for storing articles to be treated and comprising weight sensing means (6) interposed between the cabinet (1) and at least one foot element (4) provided on an outer base portion (5) of said cabinet (1) for supporting the machine, characterised in that said weight sensing means (6, 26) comprise a first electrically conductive arm (7, 27) receiving the foot element (4) and a second electrically conductive arm (8, 28) associated to the cabinet (1), said arms (7, 27, 8, 28) protruding parallel one another from a transversal joining member (9, 29) thereby defining a clearance (10, 210) therebetween, a detector (11, 211) being arranged within said clearance (10, 210) for delivering an output signal indicative of a capacitance change corresponding to articles weight change.
Laundry treating machine according to claim 1 wherein said first electrically conductive arm (7, 27) is polarized to a ground potential and said detector (11, 211) comprises a measuring electrode (13, 213a) placed within the clearance (10, 210) and associated to and electrically insulated from said second arm (8, 28).
Laundry treating machine according to claim 1 or 2 further comprising a microcomputer for receiving signal output by detector (11, 211) and adapting machine working operations.
Laundry treating machine according to any preceding claim wherein said arms (7, 27, 8, 28) and said transversal joining member (9, 29) define a "C" shaped structure.
Laundry treating machine according to any preceding claim wherein said first arm (27) is divided into two portions (27a, 27b) by an opening (220) extending from joining member (29) in a direction substantially perpendicular to the latter.
Laundry treating machine according to claim 5 wherein each of said two portions (27a, 27b) defines a gap (210a, 210b) with the second electrically conductive arm (28).
Laundry treating machine according to claim 6 wherein a couple of electrodes 213a, 213b are associated to and electrically insulated from second arm (28), in correspondence of said gaps (210a, 210b), and said portions (27a, 27b) are polarized to a ground potential.
Laundry treating machine according to any claim 5 to 7 wherein one of said portions (27a, 27b) has a hole for threadly receiving said foot element (4).