Washing machine with improved anchoring means for the washing assembly

Abstract: Household-type washing machine or similar appliance in which the washing assembly (3) is anchored to the stationary structure (1) by means of one or more anchoring devices (2), each one of which comprises at least two elastic elements (10, 20) arranged in series. Firmly secured to each elastic element there is a rigid element (15, 25) whose free end portion (15) protrudes beyond the other elastic element (20). The elastic elements (10, 20) work in this manner as compression elastic means and the elastic constant of the anchoring devices (2) readily and automatically adapts to the different conditions that happen to prevail during a washing cycle.

Description: The present invention refers to a washing machine, in particular such a washing machine for residential and similar uses, wherein it is hereby intended that, as used here, the term washing machine shall be understood to include also similar appliances, such as washer-driers. Washing machines are generally known to comprise an outer stationary structure (which is generally referred to as "casing" in the art) and a so-called internal washing or oscillating assembly which substantially includes a tub enclosing and supporting a rotating drum driven by an electric motor. Elastic or spring elements, which may sometimes be integrated into friction-type shock-absorbing anchoring devices, are generally used to anchor such a washing assembly on to said outer stationary structure. Examples of the prior art are for instance given by the washing machines disclosed in US-A-3 744 746, FR-A-2 531 461, EP-A-80 243 and EP-A-265 004. It is a main purpose of the present invention to provide an improved anchoring of the washing assembly to the outer stationary structure in view of facilitating the fabrication of the washing machine, reducing the costs and boosting the reliability thereof, this representing as many aims that are of paramount importance for mass-manufacturing companies with an output that usually reaches up to several hundreds of thousands of units per year. A washing machine having the features as recited in the appended claims enables these and further aims to be reached, as this will become more readily apparent from the detailed description that is given below by way of non-limiting example with reference to the accompanying drawings, in which: Figure 1 is a simplified schematical view of a household washing machine of the front-loading type; Figure 2 is a front view of a first embodiment of a washing assembly anchoring device according to the present invention, before its component parts are assembled; Figure 3 is a view of the device of Figure 2 in its fully assembled condition and installed in a washing machine such as the one illustrated in Figure 1; Figure 4 is a view of a variant of the above cited embodiment, upon completion of the assembly of the component parts thereof; Figure 5 is a view of a second embodiment of a washing assembly anchoring device according to the present invention, with its component parts in their assembled condition. With particular reference to Figure 1, a household-type washing machine can be noticed to comprise an outer stationary structure 1, in the form of an outer casing, with at least a pair of anchoring devices 2 for elastically anchoring a washing assembly 3 in which an approximately cylindrical tub 4 accomodates a drum 5 that is arranged to rotate about a substantially horizontal axis as driven by an electric motor (not shown). Said anchoring devices 2 are hooked on to eyelets 7, which are integral with the side wall of the stationary structure 1, and, respectively, to eyelets 8 that are integral with the outer surface of the tub 4 and, therefore, integral with the washing assembly 3. Loading and unloading of the clothes to be washed, ie. the washload, occur through a circular aperture 6 provided in the front portion of the washing assembly 3 and a therewith associated aperture, capable of being closed with a corresponding door (not shown), provided in the front wall of the stationary structure 1. The washing machine is not described here any further in its overall construction owing to the fact that no further details are actually needed to ensure an adequate understanding the present invention and, on the other hand, the same washing machine may even be of the top-loading type, considering the universal nature of the anchoring means according to the present invention as far as the application scope thereof is concerned. A first embodiment of an anchoring device 2 for a washing assembly 3 according to the present invention, as illustrated in Figures 2 and 3, consists merely of a pair of special compression-type helical springs 10 and 20, which elongate along the same axis x-x, and an annular seat 30 arranged therebetween. The first such helical spring 10, whose end portions 11 and 12 consist of a first and a second circular coil, has a length A R according to the axis x-x when at rest. From said first end coil 11 of the spring 10, in correspondence of the point indicated at 13, a relatively rigid prolongation 14 extends in an uninterrupted manner. Said prolongation 14, which is substantially rectilinear, extends inwards into the same spring 10, and its free end 15, which is in the shape of a hook, is aligned along the common axis x-x of the two springs 10 and 20. The second such helical spring 20, whose ends 21 and 22 consist again of a first and a second circular coil, has in turn a length B R , according to said axis x-x when at rest, wherein such a length B R is greater than said length A R of said first spring 10 when the latter is at rest. From said first end coil 21 of the spring 20, in correspondence of the point indicated at 23, a relatively rigid prolongation 24 extends in an uninterrupted manner. Said prolongation 24, which is substantially rectilinear, extends inwards into the same spring 20, and its free end 25, which is in the shape of a hook, is aligned along the common axis x-x of the two springs 10 and 20. For completing the assembly in view of obtaining an anchoring device 2, said second end coils 12 and 22 are pressed against the upper face 31 and the lower face 32, respectively, of said annular seat 30, said upper and lower faces being appropriately shaped so as to enable the two springs 10, 20 to link up with each other along a transverse plane with respect to their common axis x-x. This operation anyway requires for the prolongation 14, which extends from the first spring 10, to be inserted inside the second spring 20 and, correspondingly, for the prolongation 24, which extends from the second spring 20, to be inserted inside the first spring 10. Such an operation may be made still easier, ie. more convenient to perform, if the lengths along the axis x-x of the prolongations 14 and 24 (indicated at C and D in Figure 2) are both greater than the lengths A R and B R of the springs 10 and 20. However, this shall not be intended as a limiting feature of the present invention. According to a main feature of the present invention, when an anchoring device 2 is installed in a washing machine, the hook 15 that forms the free end of the prolongation 14 extending from the first helical spring 10, comes into a position in which it is protruding beyond the free end 21 of the second helical spring 20 and is attached to an eyelet 8. The hook 25, which on the contrary forms the free end of the prolongation 24 extending from the second helical spring 20, comes in turn into a position in which it protrudes beyond the free end 11 of the first helical spring 10 and is so able to be attached on to an eyelet 7. It will of course be appreciated that the device 2 can also be installed in the other way round, ie. upside down, so that the hook 25 is anchored on to the eyelet 8 provided on the washing assembly 3 and the hook 15 on to the eyelet 7 provided in the stationary structure 1 of the washing machine. Upon having been loaded with the clothes to be washed, and the water required to perform the related washing cycle, the washing assembly 3 may reach up to a weight of as much as 35 kg. This causes the hooks 15 and 25 to move away from each other and, therefore, brings about a further compression of the springs 10 and 20 which become shorter along their common axis x-x, while however remaining linked up to each other by the action of the annular seat 30 thereof, down to their length Aw and B W , respectively, as best shown in Figure 3. The Applicant has found it to be of advantage if, in this condition, at least the shorter spring 10 is fully compressed (ie. "into a pack"), ie. if it has a length A W = A MIN , in such a manner that the anchoring device 2 becomes very rigid. In this way, the invention offers the practical advantage that the washing assembly 3 keeps substantially still, ie. does not move, with respect to the stationary structure 1 of the washing machine, without any risk of shocks, throughout the various phases of the washing cycle that are carried out with the drum 5 full of clothes and wash liquor and rotating at a low speed (for instance in the order of approx. 60 to 80 rpm). When, in accordance with the washing cycle, the wash liquor is let off the drum 5 and the latter is driven to rotate at a high revolution speed (which may reach up to as many as 1,500 rpm) in view of carrying out the final spin-extraction phase, the washing assembly 3 turns out to be considerably lightened, wherein it comes down to a weight that may be in the order of 22 kg or so, which thing does markedly contribute to reduce the compression stress which is imposed to the anchoring device 2. The springs 10 and 20 extend at this point to a length A S > A W and B S > B W , respectively, which is anyhow sufficient to ensure that the hooks 15 and 25 keep protruding beyond the free ends 21 and 11, respectively, while remaining linked up to each other owing to said second end coils 12 and 22 thereof engaging the faces 31 and 32 of the annular seat. When the drum 5 of the washing machine rotates at a high speed, the anchoring device 2 finds therefore itself with its springs 10 and 20 that work in series with each other, so that its elastic constant reaches such a value as to effectively reduce the transmission of the oscillations of the washing assembly 3 to the stationary structure 1, this being effective in bringing about obvious advantages, particularly in the case of unbalanced washloads in the rotating drum. It clearly emerges from the above description that, from a construction point of view, the anchoring device 2 has advantageously a particularly simple and low-cost construction, so that it ultimately has just a reduced impact on the overall cost of the washing machine. From an operational point of view, the described anchoring device has the advantage that its elastic constant has the ability of immediately and automatically adapting to the different conditions that are encountered during a washing cycle, ie. the different weights of the washing assembly 3 and the different revolving speeds of the rotating drum 5. A variant of this first embodiment of the present invention is illustrated in Figure 4 and calls for the use of a housing 100 around an anchoring device 2 as described above with reference to Figures 2 and 3. Said housing 100 comprises a first and a second portion 110 and 120 which are in the shape of cups, are made of injection-moulded plastic material and are snap-fitted together along their mouth portions thanks to the provision of respective male protrusions 111 and female protrusions 121. Most appropriately, through the use of a suitable tool, said two portions 110 and 120 of said housing 100 can subsequently be separated from each other, for instance in the case that repairs have to be carried out in the course of the life of the washing machine in which said anchoring device is installed. The springs 10 and 20 are housed in said housing 100 in such a manner that their first end coils 11 and 21 are capable of abutting against the inner surfaces of the bottom portions 112 and 122, whereas their second end coils 12 and 22 ensure their remaining mutually linked up by means of the annular seat 30. In this way, the springs 10 and 20 are compressed and reach a length of A O < A R and B O < B R , respectively, so that the distance between the bottom portions turn out to be L ≃ (A O + B O ). In the same bottom portions 112 and 122 there is provided an elongated aperture 113 and 123, respectively, to enable the hooks 15 and 25, which form the free ends of the prolongations 14 and 24, to protrude from the housing 100 when the anchoring device is mounted in the washing machine between the washing assembly 3 and the stationary structure 1. It therefore ensues that during the operation of the machine, which takes place in exactly the same manner as described earlier with reference to Figures 1 and 2, more or less conspicuous clearances remain (depending on the different conditions occurring during a washing cycle) between the first end coils 11 and 21 of the springs 10 and 20 and the therewith associated bottom portions 112 and 122 of the housing 100. In order to limit the amplitude of the oscillations of the prolongations 14 and 24 of the springs 10 and 20 in a direction which extends transversally with respect to the axis x-x, rubber noise-damping blocks (not shown in Figure 4, but well known in the art) can suitably be inserted in the eyelets 113 and 123. In any case, the housing 100 is used to the sole purpose of protecting the springs 10 and 20, as well as the annular seat 30, thereby making it easier and more convenient for the anchoring device to be handled up to the moment in which it is installed in the washing machine, so that the same housing may also be manufactured using some low-grade plastic material, ie. a plastic material with reduced mechanical properties. A second embodiment calls for at least a washing assembly anchoring device of the type illustrated in Figure 5 to be mounted in a washing machine, wherein said anchoring device comprises three helical springs 40, 50 and 60, of which at least one has a shorther length than the remaining ones, said three springs being arranged in series along the same axis y-y. Namely, the upper spring 40 has its lower end 42 welded or, anyway, joined to the upper end 51 of the intermediate spring 50, while the lower end 52 of this intermediate spring is welded to the upper end 61 of the lower spring 60. Inside said three springs there are extending two parallel metal rods 70 and 80, whose free ends 71 and 81 are in the shape of hooks, while their opposite end portions 72 and 82 are threaded. Two rigid plates 74 and 84 arranged perpendicularly to the axis y-y are provided with a pair of holes 75, 76 and 85, 86, respectively, through which the opposite end portions 81, 72 and 71, 82, respectively, of said rods are able to pass. Lock-nuts 73 and 83 are screwed on to said threaded end portions 72 and 82 in such a manner as to firmly join the upper spring 40 with the first rod 70 through its upper end 41 and the plate 74, and the lower spring 60 with the second rod 80 through its lower end 62 and the plate 84. The distance D at rest between the plates 74 and 84 upon completion of the assembly of the anchoring device can be adjusted by means of the lock-nuts 73 and 83, but it will anyway be always shorter than the sum of the lengths L' R , L" R and L''' R of the three helical springs 40, 50 and 60, which therefore are subject to a compression-type stress. In a similar manner as described above, such a compression stress is greater when the anchoring device is mounted in the washing machine between the washing assembly 3 and the stationary structure 1, ie.when, for instance, the hook-shaped end portion 71 of the first rod 70 is attached to an eyelet that is integral with the stationary structure, while the hook-shaped end portion 81 of the second rod 80 is attached to the washing assembly. The operation of the anchoring device remains substantially unaltered with respect to the afore described one. In other words, the device is very rigid when the shorter spring, ie. the intermediate spring 50 in this particular case, is fully compressed ("into a pack") during the phases of the washing cycle that are carried out with the drum rotating at a slow revolution speed, after having been loaded with the clothes to be washed and the wash liquor, and very elastic during the phases that are carried out at a high revolution speed of the rotating drum, after the wash liquor has been let off the tub, since the three springs arranged in series give rise to a very high elastic constant which is particularly beneficial in view of the ability of reducing the transmission of the oscillations of the washing assembly to the stationary structure. It will be appreciated that a number of further embodiments and variants of the present invention may be developed by those skilled in the art without departing from the scope of the present invention. In particular, mention might be made here of the possibility for also the device described above with reference to Figure 5 to be housed in a two-part housing, as well as for different elastic means to be used instead of the above described helical springs, as long as of course they operate in a compression mode, and so on.

Claims: Washing machine, wherein a washing assembly (3) comprising a wash tub (4) and a rotating drum (5) is anchored on to an outer stationary structure (1) by means of one or more anchoring devices (2) characterized in that each anchoring device (2) includes at least two elastic elements (10, 20; 40, 50, 60) arranged in series with respect to each other and in that it is the free end portion (15; 71) of a first rigid element (14; 70) which is integral with a first end portion (11; 41) of a first elastic element (10; 40) that is.anchored to the outer stationary structure (1), while the free end portion (25; 81) of a second rigid element (24; 80) which is integral with a second elastic element (20; 60) is anchored to the washing assembly (3), so that the free end portion (15, 71) of the first rigid element (14, 70) is able to protrude beyond the first end portion (21; 62) of said second elastic element (20; 60) and the free end portion (25; 81) of the second rigid element (24; 80) is able to protrude beyond said first end portion (11; 41) of the first elastic element (10; 40). Washing machine according to claim 1, characterized in that the free ends (15, 25; 71, 81) of said first and said second rigid element (14, 24; 70, 80) are in the form of hooks. Washing machine according to claim 1 or 2, characterized in that said rigid elements (14, 24) consist of prolongations extending uninterruptedly from a point (13, 23) of said first end portion (11, 21) of the respective elastic element (10, 20) within the same elastic elements (10, 20). Washing machine according to any of the claims 1 to 3, characterized in that said first and second elastic elements (10, 20) are in the form of helical springs extending along the same axis (x-x), which are joined to each other by means of the opposite faces (31, 32) of an annular seat (30) extending transversally with respect to their axis (x-x) and capable of retaining the coils that constitute the second end portions (12, 22) of the same springs (10, 20). Washing machine according to any of the claims 1 to 4, characterized in that the free end portions (15, 25; 71, 81) of said first and said second rigid element (14, 24; 70, 80) are substantially aligned along the same axis (x-x; y-y). Washing machine according to claim 1 or 2, characterized in that said first and second elastic elements (40, 60) are helical springs that are joined to each other through the end portions (51, 52) of a third helical spring (50) extending along the same axis (y-y). Washing machine according to claim 6, characterized in that said rigid elements consist of rods (70, 80) extending parallelly to said elastic elements (40, 50, 60) and having the other end portions thereof (72, 82) that are solidly joined to said first end portion (41, 62) of said first and said second elastic element (40, 60) by means of a screw thread, a lock-nut (73, 83) and a pair of rigid plates (74, 84) arranged perpendicularly to the axis (y-y) of the same springs. Washing machine according to any of the preceding claims, characterized in that during a part of the washing cycle, preferably when the drum (5), loaded with the clothes to be washed and the wash liquor, is driven to rotate at a slow revolution speed, at least one of said elastic elements (10; 50) is fully compressed. Washing machine according to any of the preceding claims, characterized in that said elastic elements (10, 20) are enclosed in a housing (100) that extends along said axis (x-x) and is provided with apertures (113, 123) in the form of elongated eyelets capable of accomodating removable inserts to guide said rigid elements (14, 24) during the oscillations of the washing assembly, in a manner that their respective free end portions (15, 25) are able to pass therethrough and protrude therefrom. Washing machine according to claim 9, characterized in that said housing (100) consists of two parts (110, 120) which are at least prevailingly made of plastic material and are integrally provided with separably, eg. threaded or snap-fitting joinable means (111, 121) enabling said parts to be fastened together.

Inventors: COLOMBERA GIOVANNI, COLOMBERA, GIOVANNI
Applicants: ELECTROLUX ZANUSSI ELETTRODOME, ELECTROLUX ZANUSSI S.P.A.
Application year: 1998
Main classification: D06F37
IPC codes: F16F3, F16F1, D06F37