FR2545512A1 - TANK WASHING MACHINE COMPRISING A PART OF SYNTHETIC MATERIAL - Google Patents

Abstract

THE INVENTION CONCERNS A HORIZONTAL DRUM LAUNDRY WASHER MACHINE MOUNTED IN A TANK CONSISTING OF TWO PARTS, A BODY 1 AND A LID 5 TIGHTENED ONE AGAINST THE OTHER BY AXIALLY PRESSING AN ELASTIC SEAL 11, AT LEAST ONE OF THE TWO DISSOCIABLE PARTS 1 AND 5 OF THE TANK BEING MADE OF A THICK SYNTHETIC MATERIAL. ACCORDING TO THE INVENTION, THE BODY 1 AND THE COVER 5 LY AGAINST THE OTHER ON A SINGLE RIGID PERIPHERAL STOPPER LOCATED ON ONE SIDE OF THE SEAL 11 SO THAT THE DEFORMATION OF THE SYNTHETIC MATERIAL DURING THERMAL SHOCK COMPRESSES THE SEAL BY SWIVEL AROUND THE STOPPER.

Description

PLASTIC TANK / LID SEALING

  The invention relates to a washing machine with horizontal axis drum mounted rotatably in a tank intended

  to receive the washing and rinsing water, said tank being suscep-

  tible of undergoing rapid and significant variations in temperature during filling with water, said tank consisting of at least

  two dissociable parts, on the one hand a body, with sensitive shell-

  horizontal cylindrical frame, provided with a substantially vertical bottom,

  and on the other hand a cover capable of closing the body in op-

  installed from the bottom, body and cover being tight against each other

  for the assembly of the tank and cooperating by ribs and rai-

  peripheral nipples axially pressing an elastic seal

  tick, at least one of the two separable parts of the tank being made of a thick synthetic material Such a machine is

  for example described in the German utility model N O 1 885 212.

  In this example, the two parts of the tank - in contact are

  synthetic materials (organic macromolecular compound).

  A bead at the periphery of the body shell is hollowed out of a groove containing the seal, bead and seal bearing against a flat radial surface of the cover The cover is furthermore provided with a peripheral centering rib Body and cover are kept assembled by a V-section ring The plastic cover is lined with a metal flange on which

is supported by the assembly ring.

  Such an achievement is inspired by the traditional

  manufacture of a metal tank It does not take into account the behavior

  physical material of synthetic materials, namely: the tendency to creep, or permanent deformation, in particular when hot, poor thermal conductivity and a high coefficient of

  thermal expansion, which generate syn-

  aesthetic, during rapid temperature variations, gradients -1- 2-

  thermal and stresses causing deformations, reversible

  or not The table below makes it possible to compare the properties of a synthetic material such as a lightened polypropylene with a normal steel, by giving orders of magnitude: conductivity coefficient of thermal expansion polypropylenei i -6 -1 polypropylene 0, 15 W m deg 150 107 deg lightened_ acernrm T 11 6 -1 normal steel 50 wm deg 1 12 107 deg 7 The temperature cycle to which a washing machine is subjected includes, for example, slow heating of the water

  from 15 'C to possibly 950 C, followed by full filling

  additional with cold water for rapid cooling to 600 C before emptying, which is followed by filling with cold water of a first rinse water.

  the tank of a machine as described above, it was observed to

  bearing water leaks The phenomenon can be analyzed by measuring the angle between the two assembled tank parts,

  body shell and cover, in the vicinity of the assembly area.

  For example, this measurement can be carried out by means of a strain gauge bridge bonded to an elastic jumper pressing the two parts against each other. It appears that the stresses of thermal origin rotate these areas around a axis tangent to the periphery of the assembled parts Movements of 0.6 mm were measured in a few seconds at the joint In the example of the German utility model 1 885 212, the body and the cover are

  pressing one on the other on either side of the joint, any deformation

  mation of one of these two parts creates a decompression of the joint.

  If the decompression is abrupt, the joint, expanding only slowly

  let some water run out.

  The invention aims to eliminate this incident In a washing machine of the type described in the preamble, it is characterized by the fact that the body and the cover rest against one another on a single rigid peripheral stop located d 'a

  side of the joint, so that the deformation of the synthetic material

  that during rapid temperature variations compresses the joint by pivoting around said stopper It is within the reach of the skilled person to determine-what is the direction of the deformations of the synthetic material generated by the thermal gradient appearing during

  thermal shock, for example with the measurement method mentioned above

  The invention in particular avoids using a counter cover

  and a metal band, as illustrated by the user model

  German unit 1 885 212, which, in addition to their cost, present the risk of forcing the synthetic material to progressive creep, which

  permanently compromise waterproofing.

  In particular in the case of a washing machine whose tub is filled with cold water and undergoing thermal cycles

  as described above, the deformation corresponds to a contraction

  abrupt tion of the material close to its internal surface while near the external surface the temperature acquired during washing of the laundry keeps the material expanded for a certain time:

  several seconds or tens of seconds This generally results

  a rotation of the assembled elements and their convex bulging

  vexity turned towards the outside of the tank Under these conditions if,

  in a machine according to the invention, the tank contact stop

  cover is located inside the tank with respect to the peripheral seal, the bulging has the effect of compressing the seal at

moment of thermal shock.

  In another particular case, the thermal shock can come from filling a cold tank (200 C approximately) with hot water (600 C for example) In this hypothesis, the rotation of the assembled parts is generally reverse creating a convexity turned towards the inside of the tank If in a machine conforming to

  the invention, the tank-lid contact stop is located outside

  laughter of the tank with respect to the peripheral joint, the deformation

  also compresses the joint at the time of thermal shock.

  In a particularly recommended embodiment,

-3-

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  mandé of the invention, the tank-lid assembly is maintained by

  elastic jumpers whose ends are in respec- tive support

  on the tank shell and the cover at sensitive points

  aligned in line with the tank-lid contact stop This arrangement keeps the elastic pressure of the jumpers approximately constant during the bulging of the assembled parts In addition, it prevents the creep of the synthetic material in line with said jumpers, creep which would occur if the points of 'application

  riders were cantilevered.

  The following description and the drawings illustrate a

  exemplary embodiment of the invention.

  FIG. 1 is a view in longitudinal section through

  part of a washing machine tank in accordance with the invention

tion.

  Figure 2 is an enlarged section of the connection zone.

  stringing of the two parts of the tank of figure 1.

  Figure 3 is a section identical to Figure 2

  in which the deformations due to thermal shock have been exa-

  managed. The figures illustrate an example of a washing machine intended to be supplied with cold water exclusively. It is a top-loading washing machine with rotary drum.

with horizontal axis.

  Figure 1 shows a tank made up of two parts

  made of lightened polypropylene with a general thickness of 6 mm A first part

  tie 1, or body, consisting of a substantially cylindrical ferrule 2 of substantially horizontal generatrices, provided with a bottom 3 carrying in its center a bearing housing for the drum 4 A second

  part or cover 5 capable of closing the body and also bearing

  Lely in its center a bearing housing for the drum 4 The ferrule 2 receives at its top a hopper 6 for loading the laundry, corresponding to a door (not shown) of the drum 4 The

  drum is made at least partially of stainless steel sheet

perforated dable.

  The tank cover 5 is provided with a central rib

  -5- trage 7 whose outer contour corresponds to the inner contour of the shell 2 Outside of this rib 7, the cover

  has a radial planar annular surface 8, i.e. per-

  pendulum to the direction of the generators of the cylindrical shell

  drique. The vessel shell has its wall ending in a radial plane with an edge 9 intended to abut on the surface

  ring 8 of the cover, during assembly of the tank Ex-

  térieur of this edge 9, the ferrule comprises, on its periphery, a rib 10 whose longitudinal extension 14 towards the cover is recessed relative to the edge 9 and which forms opposite to the

  cover at an acute angle with the ferrule surface Facing the cover

  key, the rib 10 has a peripheral groove receiving a

elastic seal 11.

  For the assembly of the two tank parts 2 and 5,

  the cover is pressed against the edge 9 forming a stop, against the

  tre of the elasticity of the joint 11 The assembly is maintained by elastic jumpers or staples 12 distributed at the periphery These jumpers 12 are anchored on the one hand in the acute angle formed by the rib 10 with the surface of the ferrule 2, and on the other hand in a recess 13 hollowed out on the surface of the cover The recess 13 is located in such a way that the elastic force exerted by each rider 12 passes substantially through the abutment zone of the edge 9

  against the surface 8, along the axis XX shown in FIG. 2.

  During washing and rinsing operations, the behavior of a machine according to the invention as described above is as follows. The washing water is admitted cold (10 to C) in the tank and mixed with the products of washing She is

  then heated by means of an electrical resistance (not shown

  sensed) to the desired wash temperature, which can reach

  dre 950 C This heating is slow, its duration depends on the quantity of laundry and water, the initial and final temperatures of the water, but it is about 10 to 30 minutes At the end of this phase, the

  mass of the polypropylene in the tank wall has reached a temperature

  almost uniform and close to that of water The slowness of -6-

  heating is such that the temperature gradient in the poly-

  propylene remains weak, so that the deformations remain slow and weak (compression of the joint slowly decreasing by at most 0.1 mm) The resilience of the material constituting the joint, such as cellular synthetic rubber, is high enough for the joint compensates for this slow and weak deformation and maintains

the tightness of the tank -

  When the washing is finished the tank is drained, possibly after partial cooling of the bath by adding cold water The tank is then filled again with cold water for the first rinsing of the laundry It is during this first admission of cold water (for cooling or rinsing) in the hot tank that the thermal shock described above occurs, the tank deforming quickly and momentarily as indicated so

  exaggerated figure 3 On a washing machine tank according to the

  vention this deformation corresponds to a rotation around the contact area 8, 9 of the cover and of the tank body, leading

  to the sudden compression of the seal 11, which strengthens the seal.

  The inverse deformation (back to figure 2) is done slowly,

  it corresponds to the complete cooling of the mass of polypro-

pylene.

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Claims (4)

  1 washing machine with horizontal axis drum mounted rotatably in a tank intended to receive the washing and rinsing water, said tank being liable to undergo rapid and significant temperature variations during filling with water, said tank consisting of at least two separable parts, on the one hand a body, with a substantially cylindrical horizontal shell, provided with a substantially vertical bottom, and on the other hand a cover   likely to close the body away from the bottom, body and cover   key being tightened one against the other for the assembly of the tank and cooperating by peripheral ribs and grooves axially pressing an elastic seal, at least one of the two   separable parts of the tank being made of synthetic material   thick, characterized by the fact that the body and the cover   rest against each other on a rigid rigid peripheral stop   that located on one side of the joint, so that the deformation of the   synthetic material during rapid temperature variations   prime the joint by pivoting around said stop -   2 washing machine according to claim 1, the tank is filled with cold water, characterized in that the stopper   tank-lid contact is located inside the tank compared to port to the peripheral joint.   3 washing machine according to claim 1, the tank is filled with hot water, characterized in that the stopper   tank-lid contact is located outside the tank in relation to port to the peripheral joint.   4 Washing machine according to any one of the claims.   1 to 3, characterized in that the tank-cover assembly   key is held in place by elastic jumpers, the ends of which rest respectively on the shell and the cover   at points substantially aligned with the tank contact stop lid.