ES2358541T3 - WASHING MACHINE WITH IMPROVED PERCEPTOR OF THE LOAD WEIGHT. - Google Patents

Abstract

Washing machine comprising an outer casing housing (1) an oscillating washing assembly (2) suspended elastically to said casing through at least a spring (3,4), at least a vibration-damping strut (5,50) placed between an outer portion of said washing assembly and a respective anchoring point which is connected, even elastically, to said casing, measurement means (12) able of measuring the excursion of the washing assembly, and able of generating and transferring a signal representative of the vertical excursion of the washing assembly; said casing is provided, preferably on the lower part if it, with elastic means (7,8,77,88,52) able of assuming a predetermined resting position, and said excursion measurement means are applied between a definite point (13) firmly connected to said casing, and a predefined position of said elastic means. An end part of said damping strut is engaged to a lower portion (6) of said washing assembly, while the opposite end part of the same damping strut is engaged to an anchoring point (5A,55) placed on said elastic means. In a preferred embodiment said elastic means comprise two springs, preferably spirally shaped, which are independent, aligned, vertically oriented, connected to each other between the two respectively facing sides (7B,8B); the opposed extremes of said two springs are solidly connected to respective distinct portions of said casing.

Description

The present invention relates to a washing machine, such as a laundry machine or a combined laundry machine and dryer, provided with means intended to measure the weight of laundry items loaded in a washing assembly that is elastically suspended. of the machine frame with the help of elastic means such as vibration dampers or the like.

In the prior art, some solutions are known that are provided with means capable of detecting the weight of the load and that are based on various types of well-known recipients, comprising magnetostrictive perceivers, also called load cells, as per example in US 6,460,381, or capacitive elements as in US 4,742,698, or even simpler elements representative of a displacement, evidently associated with suitable elastic means.

GB 2087438 discloses a usual solution in which the washing machine is provided with a washing tank mounted with sensing and transducer means that provide information on the weight of the tank and, by subtraction, on the weight of the washing load.

Also, the (published) patent EP 1264925 discloses a washing machine with a piece of furniture, provided with support legs, and which houses a washing assembly suspended elastically from the structure of the machine by means of at least one shock absorber and comprising less a perceptor of the displacement of said washing assembly, in which said perceiver is interposed between said cushion and the structure of the machine, upstream of said support legs, such that the variations in weight of the assembly of washing regardless of the braking force of the shock absorber and the weight of the machine.

However, although all the aforementioned solutions are theoretically effective and functional, in practice they have not been used extensively and appreciably due to the following common drawback: when these sensors are activated, they provide information that is a function of the absolute vertical position of the tank, due to the fact that said absolute vertical position is a function of the opposite actions between the total weight of the tank, drum and load included, and the action of the elastic support of the support springs, from which it follows that the Load weighing offers extremely uncertain results.

In fact, the weight of the load is normally only a small fraction of the overall weight of the tank, drum included and, thus, the obvious variations in the actual weight of the tank due to the natural variations of the various construction factors inevitably involved. and whose total magnitude is truly unknown, prevents an accurate measurement of the exact load, whose real value is "masked" by such variations.

However, if it is sought that said inconvenience is less important by detecting an initial reference measurement related to the weight of the empty tank and then proceeding to the detection of the weight of the load by measuring the additional variation after its introduction, It encounters the inconvenience caused by the circumstance that the displacement of the perceiver, actually used, will vary over a very wide range.

However, as is well known by the person skilled in the art, satisfying said requirement will always entail very complicated and particularly expensive solutions, whatever the technology and type of device that are normally used for the receiver of selected offset

Therefore, one purpose of the present invention is to provide a washing machine equipped with means for measuring the weight of the wash load, based on the displacement of the tank, in which the above-mentioned drawbacks encountered in the prior art, be minimized.

In particular, one purpose of the present invention is to provide a washing machine of the kind specified above, which is intended to measure the wash load with a high degree of accuracy and reliably, making use of a less expensive solution.

In accordance with the present invention, these and other objectives are achieved in a washing machine with weight detection means incorporating the characteristics and particularities that are defined and indicated in the appended claims.

In any case, the features and advantages of the present invention can be more readily understood from the description given below by means of a non-limiting example with reference to the accompanying drawings, in which:

-

Figure 1 is a schematic view of a washing machine according to the present invention;

-

Figure 2 is an enlarged view of a detail of the means of detecting the weight of the washing machine according to a first embodiment thereof;

-

Figure 3 is a view of a different embodiment of the weight detection means illustrated in Figure 2;

-

Figure 4 is a diagrammatic view of the characteristic force / elongation curve of the spring 2 shown in Fig. 2;

-

Figures 5A and 5B are, respectively, a vertical front view and a perspective view of another embodiment of the invention; Y

-

Figure 6 is an enlarged view of an improved embodiment of the weight sensing means according to the invention.

With reference in particular to the aforementioned figures 1 and 2, the washing machine according to the invention, whether it is a top-loading or a front-loading, comprises an external furniture 1 that houses an oscillating tank 2 which is suspended elastically of the frame of the washing machine by means of springs 3 and 4 that elastically support said tank with respect to said furniture in known manner, and a damping post 5 located between an outer part 6 of said tank and an anchor point 5A whose exact position this document explains: said furniture 1 is provided, in its lower part, with a pair of springs 7, 8 which, preferably, have a helical shape, independent in the sense that they are different, are aligned, oriented vertically and connected each other on both sides 7B, 8B respectively facing each other.

The opposite ends 7A, 8A of said two springs 7, 8 are fixed, obviously in a vertical position with respect to each other, in respective different and vertical parts 9, 10, integral with said furniture 1.

A horizontally extending position arm 11 is connected to said two opposite sides 7B, 8B of said two springs 7, 8 which, then, coincide at the same physical point, even when their position is variable.

Said anchor point 5A of said damping upright 5, is identified in said position arm 11.

Means 12 for measuring the displacement are mounted between said position arm 11 and a specific point 13 different from said furniture; said means are located vertically below or above said arm 11; Said measuring means may be of any of several types that are available in the prior art and which, since not forming part of the present invention, are not explained in greater detail.

The information generated by said measuring means 12 and which detects the vertical position of said two opposite sides 7B and 8B, is sent to a command and control unit, not shown, capable of handling the received signals according to the following logic :

Before drying begins and before the washing load is introduced into the drum, the net weight of the tank / drum assembly, obviously without the weight of a possible water load, is supported by the overall action of said springs 3 and 4 and by said springs 7 and 8; however, said springs 7 and 8 are reciprocally maintained in an equilibrium position, reacting spontaneously to the force applied to them.

However, said force cannot be greater than the frictional force of said damping upright 5 since, otherwise, the force exerted by said part 6 on said damping upright 5 would be transmitted by the damping upright itself which, consequently, would change its own internal settings; The force that is then actually transmitted to said position arm 11 is the minimum force and, consequently, the position arm adopts a rest position that is detected and transmitted by said displacement sensor 12.

Thus, said signal is capable of providing the information of a position corresponding to the configuration that, automatically, adopts said cushioning amount with the empty tank; in conclusion, the signal of said perceiver 12 can be taken as a reference signal with the empty tank.

When the wash load is introduced into the drum, said part 6 of the tank will press on said shock absorber 5 which obviously tends to shorten due to the elastic reaction exerted on the position arm 11; however, this effect is only valid until the elastic reaction of the arm 11 becomes greater than the frictional resistance of the damping post 5; in fact, when the force acting on the shock absorber 5 due to the effect of the weight of the load becomes less than the frictional force of the shock absorber itself, it rigidly transmits said force to the position arm 11 which, consequently, acts on said two springs 7 and 8; these then allow the same arm 11 to adopt a final position duly detected by the movement sensor 12 itself.

Therefore, by properly regulating the friction forces of said damping post 5 and the forces of said springs 7 and 8, a situation can be reached in which it is possible to find a relationship that connects the movement of the sensor, that is, the distance between the initial position of the recipient with the empty tank and the position it adopts after the introduction of the load, due to the effect of the load, that is, the weight of the load.

A method can then be obtained for simple, reliable and inexpensive weighing of the wash load contained in the drum.

The advantage of such a method and of the related means is that the movement of the recipient can only be ascribed to the weight of the wash load and not to the weight of the tank, thus eliminating the denounced effect of "masking the load" and obtaining, consequently, an appropriately accurate measurement.

In addition, due to the intrinsic precision of said measurement means, an even very limited displacement can be achieved, in operation, of said sensor 12 which, however, can be accepted.

And, therefore, by means of a limited work shift, the ultimate goal of the invention is achieved, consisting in using a position sensor that is reliable and yet very cheap.

The described solution suggests some advantageous improvements:

The first improvement consists of the following: in order to ensure that with the empty tank, said shock absorber will be automatically regulated in order to exert a minimum force on said springs 7 and 8, before then introducing the wash load into the drum , a short drum rotation phase is carried out, while the tank is still empty; therefore, after said rotation phase and after the consequent agitation of the drum, it can reasonably be assumed that said shock absorber is being subjected to a force that is less than its initial friction force, that is, to a minimum force that is the force exerted by said springs 7 and 8 in rest conditions; said force can also be zeroed when the tank is perfectly supported by said springs 3 and 4, and only by them, and consequently in equilibrium position.

Under these conditions, the relevant position of the tank is detected by the receiver 12 and taken as the reference position.

The second improvement consists in the fact (see Fig. 3) that the braking action on the tank 1 is not only exerted by means of a shock absorber 5, but by two separate dampers, 5 and 50, which are located in respective positions that they are basically symmetrical with respect to a vertical plane that passes through the same center of the tank; naturally, in such a case the second shock absorber 50 is provided with a respective pair of springs 70 and 80 and an arm 110 of relevant position, and associated devices, substantially symmetrically to that applicable to the first shock absorber 5, except that there is no related position sensor, associated with said second shock absorber 50.

Such improvement allows to balance the behavior of the tank during operation and, mainly, during the initial phases of alignment of the tank, with the empty tank, and the subsequent weighing of the wash load.

The washing machine according to the invention is provided with said springs 7, 8 with an initial total force that is smaller, but only slightly smaller, than the initial frictional force of the shock absorber; with reference to fig. 4, it is desirable that the friction force "fa" be greater than the reaction force "fr" of said springs so that the displacement, from which the weight of the wash load is measured, is the greatest possible , even if it has to be limited by existing cost restrictions.

In fact, in this case, the advantage can be taken that during the initial alignment phase of the initial position of the tank, and also without such alignment, the position of the tank itself is determined with adequate precision, overcoming the predicted inaccuracies due to the normal variability of the initial frictional force of the shock absorber.

Actually, in the absurdity of the elastic forces being absolutely relevant and predominant, it would be obtained that the position of the tank would be detected with absolute precision; however, in this case it would be impossible to detect the weight of the wash load, since the variation of the position of the position arm 11 would not be affected in a sensitive way.

On the contrary, if the frictional force of the shock absorber were much greater than the elastic forces of the springs, then the weight of the load would generate a large displacement of the sensor that is not compatible with the purpose of cost containment.

A third improvement consists in providing the washing machine with suitable command and control means, capable of automatically carrying out said drum rotation phase as soon as the machine is turned on; In addition, at this time the drum is automatically locked in the closed position.

The fourth improvement consists in manufacturing said pairs of springs 7, 8 and 70, 80 as if it were a single spring with the same characteristics and working properties as the two respective springs to which it is intended to be replaced.

The relevant position arm can therefore be connected in solidarity to an appropriate intermediate part of said single spring, using connection means well known in the art.

Another improvement is shown in fig. 6; it shows that the springs used in the invention are two separate, independent and vertically aligned springs, 77, 88, with respective opposite sides 77B and 88B; said opposite sides are connected to a support base 79 solidly connected to said furniture 1.

The two opposite sides 77A and 88A of said springs are interconnected by a rod 88 that slides into said support base 79 without interfering with them so that, if the end side 77A or 88A is pressed, or pulled axially he, said force is automatically transmitted to the other spring, which is forced by a certain type of tension exactly opposite, as is easy to imagine.

In this case, the positioning arm 11 is located in the common position of the anchor point 5A of the damping post 5 with the corresponding outer side 77A of the spring 77; naturally, even in this case the position sensor 12 is firmly applied to the furniture 1 between said arm 11 and a point 130.

The embodiments set forth so far, although simple and effective, may, however, present a certain complication and their cost may continue without being entirely satisfactory, due to the use of a helical spring; An improved embodiment, aimed at achieving other results, both in terms of complication and cost, is schematically illustrated in fig. 5.

It is possible to observe that a base element 50 is provided which is configured as a flat plate and formed with an empty inner zone 51, that is, devoid of material; a flat part 52 protrudes from an inner edge 53 of said base element and extends into said inner zone 51.

In practice, said part 52 penetrates into said empty interior area 51, being basically, however, in the same plane.

The shock absorber 5 is connected with its upper part with the outer part 6 of said tank 2, as in the previously described case, while its lower part 54 is connected to a point 55 of the outer edge of said flat part 52.

The displacement sensor 12 is connected to the annular part of said base element 50 and is normally provided with a touch finger 18; in accordance with the present embodiment, the central body of said sensor 12 is firmly connected to a point 14 located in the outer annular zone of said base element 50, while the lower end of said touch finger 18 is applied against a position 16 of said flat part comprising the positioning arm 11 as previously defined; in fact, in the present case said flat part works as said arm 11 and as said two springs.

Preferably, said position 16 is located near the edge furthest from said inner edge 53 in which said flat part 52 is fixed.

Finally, said base element is firmly connected to the machine frame and, in particular, to its pedestal.

Now, it will be apparent to the person skilled in the art that such an embodiment is absolutely equivalent, from a functional point of view, to the previously described embodiments; in fact, the only apparent constructive difference refers only to the replacement of the two springs 7 and 8, aligned and facing on a common side, with the protruding flat part 52.

However, said constructive difference does not change the operation of this displacement sensor, since said part 52 is made of flexible material, whose aforementioned edge 16 can be elastically curved both upwards and downwards.

Since said base part 52 can adopt a defined rest position, when it is being forced vertically, up or down, it tends to elastically recover said rest position which, in this case, is adopted as a reference position with the drum empty.

When the drum is filled with the wash load, its weight increases accordingly and said increase is transferred to the tank. The increased weight of the tank pushes the shock absorber down which, at that time, if its resistance to initial friction is greater than the initial reaction of the spring, will push said elastic flat part 52 away from said reference resting position and making it lower, showing a drift of the position that is a function of the wash load; obviously said position drift is then immediately detected by said displacement sensor 12.

In conclusion, said elastic flat part 52 and, consequently, said displacement sensor 12 will provide information that is a true function of the actual weight of the wash load.

Claims (6)

1. Washing machine comprising an external furniture (1) housing an oscillating washing assembly (2) elastically suspended from said furniture by at least one spring (3, 4), at least one upright (5, 50) shock absorber of vibrations, located between an outer part of said washing set and a respective anchor point, measuring means (12) capable of measuring the displacement of said washing set (2) and capable of generating and transmitting a signal representative of the vertical component of the displacement of the washing assembly, in which said furniture is provided, in part thereof and preferably in the lower part thereof, of elastic means (7, 8, 77, 88, 52) capable of maintaining a position balancing, sealed said means (12) for measuring the displacement between a defined point (13) that is firmly connected to said furniture and a position arm (11) predefined connected with said elastic means (7, 8, 77, 88, 52), a terminal part of said damping upright (5) being in application with a lower part (6) of said washing assembly, while the Opposite terminal part of the same shock absorber is in application with an anchor point (5A, 55) connected with said position arm (11), characterized in that the initial force of the elastic means (7, 8, 77, 88, 52) it is less, at least fractionally less, than the initial frictional force of the damping post (5).

2.

Washing machine according to claim 1, characterized in that said elastic means comprise two springs (7, 8), preferably helically, which are independent, and are aligned, vertically oriented, connected to each other between the two respectively facing sides (7B , 8B), because the opposite ends (7A, 8A) of said two springs are connected in solidarity with respective different parts (9, 10) of said furniture, and because said position arm (11) is connected to said facing sides (7B, 8B) of said respective springs (7, 8).

3.

Washing machine according to claim 1, characterized in that said elastic means comprise two springs (77, 88), preferably helically, which are independent and are aligned, vertically oriented, connected to each other between the two respective facing faces (77B , 88B), which are connected in solidarity with support means (79) fixed to said furniture, because the end sides (77A, 88A) of said two springs are connected in solidarity with respective ends of a rod (83), one (77A) of said end sides being connected to said position arm (11).

Four.

Washing machine according to claim 1, characterized in that said elastic means comprise a flat elastic part (52) protruding from an inner edge (53) of a base element (50) which is connected in solidarity with said furniture (1 ), and because said measuring means (12) are provided with a finger

(18) whose sensing end is in contact with a defined point (15) of said flat elastic part (52).

5.

 Washing machine according to claim 2, characterized in that said two springs (7, 8) are constituted by a single spring connected, by a respective intermediate point, with said position arm (11).

6.

 Washing machine according to any of the preceding claims, characterized in that said measuring means (12) are capable of transmitting the information generated, relevant to the position of said elastic means, to suitable treatment means, and because said treatment means are able to correlate this information with the actual weight of the wash load.