GB2148953A - Support of washing machine drums - Google Patents

Abstract

A support system includes a washing machine drum 1 resting on at least two telescopic shock absorbers in a washing machine frame 3. There may be a pair of shock absorbers 7 and a pair of shock absorbers 7'. In other arrangements, there may be from two to five of the shock absorbers, the conventional suspension springs 10 may be omitted or retained, and the conventional ballast or counterweights may be omitted or retained. At least two of the shock absorbers, here the shock absorbers 7, form angles of approximately 15 DEG with respect to the vertical. One or two shock absorbers 7' may be linked to the motor casing 9 and be at approximately 60 DEG to the vertical. <IMAGE>

Description

SPECIFICATION Support of washing machine drums This invention is concerned with the support of washing machine drums.

As is known, the centre of gravity of the drum of a washing machine, in the work stage, constantly changes position due to the movement to which the water and clothes inside it are subjected. This means that the rotating movement of the drum is accompanied by a sideways vibratory movement, as well as a vertical movement due to the effect of gravity. The frequency and amplitude of these vibratory movements vary according to the magnitude of the eccentric weight and of the number of revolutions per minute at which the drum turns.

These parasitic displacements of the drum, although they cannot be entirely eliminated, are conventionally damped with the aid of suitably placed counterweights or ballast tending to correct the deviations of the centre of gravity, and with the assistance of springs tending to reduce these displacements.

More specifically, the drum is suspended from upper springs, and is ballasted in the top with a concrete shoe and at each end with a concrete ring. A resultant pendular and tilting movement is nevertheless maintained as the rings and shoe are insufficient to curb the centrifugal force of the drum. To complete this structure, braking plates are fixed to the bottom of the drum, assisted by two resilient clips, but without the results obtained reaching the desired energy absorption level.

In the light of the problems posed by conventional technology, the solution has been arrived at of using a set of telescopic shock absorbers as damping elements.

Now then, the idea of using telescopic shock absorbers in a support system for the drum of a washing machine is in itself insufficient, as they have to have a special layout to prove operative as the damping elements.

A support system, in accordance with the present invention, comprises a washing machine drum resting on at least two telescopic shock absorbers in a washing machine frame, each of the shock absorbers being fixed at one end with respect to the drum and at the other end with respect to the frame, and at least two of the shock absorbers forming angles of approximately 15 with respect to the vertical.

Preferably, the shock absorbers are gradual dual effect shock absorbers, with hydraulic fluid, of the kind disclosed and claimed in our Spanish utility model 272 728. That extraordinarily simplified shock absorber absorbs the excess fluid in the actual displacement sleeve, through a floating lip seal which also performs the function of a sealing joint, thus avoiding fluid leaking. Said shock absorber enables the motivation speed to be regulated, increasing or decreasing the cylinder diameter.

In one arrangement, which is a preferential solution, the drum maintains its suspended position through two upper springs, and rests on two side telescopic shock absorbers, each with an angle of inclination of 15 placed in the opposite direction to the turning of the drum, and a further two shock absorbers, each arranged at an angle of 60 , also in the opposite direction to the turning of the drum, but placed between the rugged chassis or frame of the machine and a drive motor of the drum which, as is known, is connected to it, on a lower level.

The aforementioned solution can be slightly modified by removing the suspension springs, having a further two lower shock absorbers in the turning direction of the drum, also placed at 1 5', and limiting the number of shock absorbers at 60 opposing the turning movement to only one.

This solution, which offers similar functional features to the previous case, nevertheless has the disadvantage that the shock absorbers should be provided with inner return springs, at the same time as the actual number of shock absorbers is increased by one; this, apart from the corresponding negative economic repercussion, also involves certain technical problems, such as oxidation, guides and centring devices, pressures, etc. Special interest should be devoted to the problem of oxidation, since the telescopic shock absorber which has been designed to be used in the system preconized, and shown in our Spanish utility model 272 728, is able to work with water, and even better with oil, it being obvious that the need of establishing direct contact between the said fluid and the spring will lead to an oxidation process of the latter.

As another possible solution, the support system may include two upper suspension springs for the drum and four lower telescopic shock absorbers, all arranged with an inclination of 1 5'. Also, although of less interest, the simple solution is possible of four lower shock absorbers at 1 5', or four upper suspension shock absorbers, or four shock absorbers corresponding to the vertices of the frame, the drum being assisted, in such cases, by the conventional ballast or upper concrete shoe.

In accordance with other embodiments, the support system can include just three telescopic shock absorbers, in the absence of any other type of auxiliary element or load ballast, or indeed only two shock absorbers when the upper suspension springs are maintained.

More specifically, when three shock absorbers are used, two of them are arranged between the drum and the chassis base, in a side arrangement and in a favourable direction to the turning of the drum, while the third is placed on the opposite side, perfectly centred and opposite the said turning direction, all of them adopting positions with an inclination of around 15 with respect to the vertical.

In the case of using only two shock absorbers, these are placed centrally on both sides of the drum, one in a favourable position to the turning direction and the other in the opposite position, and also both with an angle of inclination close on 15 with respect to the vertical, but with the difference that in this case, when only the two shock absorbers are used, it is necessary to maintain the two upper suspension springs, and ensure that the plane in which the said springs are lying is perpendicular to the plane in which the two shock absorbers are lying.

Due to the frequency or cycles per second, the vibratory movement is determined by revolutions of the drum, and said frequency cannot be varied; however, its amplitude, on being determined by the eccentric weight, is considerably reduced, furthermore rounding off the "vibration crests" and flattening them.

The said reduction in the amplitude of oscillations, through adopting the present support system, enables the need for walls in washing machines to be completely eliminated, insofar as they act as structural elements, i.e. as a structure which withstands the load of the machines, enabling the use of a simple frame for the purpose, whereby any walls would act as mere enclosing elements, and hence could be made of considerably thinner plate than hitherto.

On the other hand, and as is obvious, the vibrations suffered by the drum act like a brake on the motor, i.e. detract power from it, whereby the said reduction in the amplitude of oscillations means a reduction in the braking effect and an increase in the turning speed of the motor, in the region of 100 r.p.m., which allows the use of less powerful motors than hitherto, and consequently a reduction in cost and consumption.

Support systems, in accordance with the present invention, will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a diagrammatic illustration of a drum for a washing machine in a front elevation view and provided with conventional damping means; Figure 1A is a partial side view of a conventional brake plate and the corresponding resilient clip; Figures 2, 3, 4 and 5 are all front elevation views, similar to Fig. 1, but showing drums for washing machines embodied in different support systems of the present invention; Figures 6, 7 and 8 show diagrammatic views respectively in side elevation, front elevation and opposite side elevation, of another embodiment of the present invention using only three shock absorbers;; Figures 9, 10 and 11 show diagrammatic views corresponding to those of Figs. 6, 7 and 8 of another embodiment of the present invention in which two shock absorbers are used and two springs; and Figure 12 finally shows an amplitude-frequency diagram of the vibrations comparing a conventional support system with the support system of the present invention.

Fig. 1 illustrates how, in accordance with conventional systems, the drum 1 of the washing machine is ballasted through a counterweight 2 placed over the drum and through a concrete ring or disc in each end of the drum. The drum 1 is suspended from the frame 3 through upper springs 4 and in its bottom area braking plates 5 are arranged with which respective resilient anchoring clips 6 cooperate. The clips 6 are fixed to the frame 3 as shown more clearly in Fig. 1A.

According to the improvements preconized, the support system for the washing machine drum, as shown in Fig. 2, is based on the use of a pair of telescopic shock absorbers 7, arranged opposing the turning direction of the drum 1, which is the direction shown by the arrow 8, and arranged to form angles of about 15 with the vertical.

In the opposite side of the machine two other shock absorbers 7' are arranged, also opposing the turning direction 8 of the drum 1, and which are placed between the actual chassis 3 supporting the assembly and the drive motor 9 of the drum which, as is conventional, is linked to the latter in its lower area.

The structure disclosed is completed with two upper suspension springs 10. arranged similarly to the conventional manner, but without the classical concrete counterweights.

In an embodiment variation, shown in Fig.

3, the said upper suspension springs can be eliminated by placing two new shock absorbers 7", also with an angle of approximately 1 5', similar to the telescopic shock absorbers 7, said new shock absorbers 7" being placed symmetrically with respect to the shock absorbers 7.

Furthermore, the shock absorbers 7' in the previous embodiment, placed at an angle of 60 with respect to the vertical, are reduced to a single unit and in a centred position.

The system also allows other variations, like that shown in Fig. 4, in which the drum 1 is suspended from the said upper springs 10, which in this case adopt a greater degree of inclination, at the same time as it rests on four telescopic shock absorbers 7 and 7", in an identical layout to those which, with the same references, have been quoted and illustrated in the previous case.

The system can be further simplified, obviously at the expense of reducing the operative qualities, by having only four lower shock absorbers 7 and 7", with the said inclination of 1 5', according to the illustration in Fig. 5, and an upper concrete counterweight 11.

In accordance with another embodiment, that illustrated in Figs. 6, 7 and 8, the drum 1 is supported by two side telescopic shock absorbers 12 and 12' which stretch from the side surface of the drum 1 to one of the side edges of the housing 3, specifically in a direction favourable to the turning direction of the drum 1 and forming an angle of approximately 15 with the vertical, whereas on the opposite side of the drum, in the centre, a third shock absorber 13 is placed, which stretches against the turning direction of the drum, between its side area and the side edge corresponding to the chassis.

In accordance with this embodiment the three shock absorbers quoted, marked with reference numbers 12, 12' and 13, in themselves form damping means for the drum, absorbing its vibrations, in the absence of upper springs, ballast or any other complementary fixing or stabilisation system.

As mentioned above, and in accordance with another embodiment, there is the possibility of reducing the number of shock absorbers to only two, as illustrated in Figs. 9, 10 and 11, in which said shock absorbers appear marked with numbers 14 and 14', in which case the conventional springs 15 for supporting the drum 1 have to be maintained.

In this case, and more specifically, the two shock absorbers quoted 14 and 14' are placed on both sides of the drum 1, being fixed between its side areas and the bottom side edges of the housing 3 and, as in the previous case, defining angles of inclination of about 15 with respect to the vertical.

In this case, special mention should be made of the fact that the two shock absorbers 14 and 14' are placed in a middle transversal plane of the machine, whereas the two springs 15 must be included in a plane perpendicular to the previous one, i.e. in a frontrear plane.

Also in this case, an optimum support system for the drum is achieved, minimising the number of shock absorbers necessary but with the essential counterpart of having to maintain the upper springs 15.

In any event, and in accordance with the illustration in Fig. 12, in which the axis corresponding to the frequency has been marked with A, and the axis corresponding to the amplitudes has been shown with B, and in which 16 shows the diagram corresponding to a conventional system, and 17 the diagram corresponding to a system in accordance with the improvements preconized, it can be seen that although the vibration frequency A is maintained, the amplitude B is considerably reduced and, furthermore, the crests are rounded off, thereby making vibration even less.

Claims (8)

1. A support system comprising a washing machine drum resting on at least two telescopic shock absorbers in a washing machine frame, each of the shock absorbers being fixed at one end with respect to the drum and at the other end with respect to the frame, and at least two of the shock absorbers forming angles of approximately 15 with respect to the vertical.

2. A support system according to claim 1, in which as well as a pair of springs, from which the drum is suspended, two shock absorbers are placed on one side of the axis of the drum, opposing the turning direction of the drum and forming angles of approximately 15 with respect to the vertical, while another two, placed on the opposite side of the said axis, are linked to a motor connected to the bottom area of the drum and form angles of approximately 60 with respect to the vertical.

3. A support system according to claim 2, in which apart from the two shock absorbers with inclinations of 1 5', arranged in opposition to the turning movement of the drum there are another two shock absorbers with the same inclination, on the opposite side, in which case the shock absorbers with inclinations of approximately 60 are reduced to a single one and the upper supporting springs are eliminated.

4. A support system according to claim 1, in which the drum, apart from being supported by two upper springs, rests on four of the shock absorbers, two on each side of the axis of the drum and all inclined with respect to the vertical at angles of approximately 1 5'.

5. A support system according to claim 4, in which a concrete shoe counterweight is arranged in the upper area of the drum and the upper supporting springs are eliminated.

6. A support system according to claim 1, in which two shock absorbers are fixed between the side area of the drum and the corresponding side edge of the frame, in a favourable direction to the turning of the drum, while a third shock absorber is placed between the opposite side area of the drum and the corresponding side edge of the frame, in the opposite direction to the turning of the drum, and in a centred position, all three of the shock absorbers having inclinations of approximately 15 with respect to the vertical.

7. A support svstem according to claim 1, in which there are two shock absorbers placed centrally on both sides of the drum, being fixed between the sides of the drum and the side edges of the lower base of the frame and forming angles of approximately 15 with respect to the vertical, one of them being in the turning direction of the drum and the other against it, and the drum being suspended from the top of the frame with the assistance of two springs, the two springs lying in an imaginary plane which is perpendicular to the likewise imaginary plane in which the two shock absorbers are lying.

8. A support system substantially-as hereinbefore described with reference to Fig. 2, Fig. 3, Fig. 4, Fig. 5, Figs. 6 to 8, or Figs. 9 to 11, of the accompanying drawings.