FR2580005A1 - - Google Patents

Abstract

A PTC 12 HEATING RESISTANT ELEMENT PASSED BY CURRENT HOTS WHEN THE MACHINE IS RUNNING. A BIMETAL ACTUATOR 14 PRESSED ON ELEMENT 12 SHOWS FAST INITIAL GROWTH THEN SLOW GROWTH. IT ACTS ON A BLADE 15 WHICH ENGAGES A ROD 18 IN A HOLE 4A OF THE LOCK 4 OF THE DOOR TO BLOCK THE OPENING. BIMETAL CONTROL ELEMENTS 10A, 10B, 10C, ELECTRICALLY CONNECTED TO THE OTHER SIDE OF ELEMENT 12, DEFORM IN REVERSE DIRECTION. A SPECIFIC HIGH HEAT INTERMEDIATE CONDUCTOR 11 INTERPOSED BETWEEN ELEMENTS 12 AND 10A, 10B, 10C DELAYS THE HEATING OF THESE LATEST BY A TIME ABOUT EQUAL TO THE INITIAL PERIOD OF RAPID GROWTH IN THE TEMPERATURE OF ELEMENT 12.

Description

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  The present invention relates to a device

  the door lock of a washing machine, in par-

  particular of a washing machine, comprising:

a support envelope;

  a PTC-type heat resisting element supported in the casing and intended to be powered by

  voltage and to warm up when the machine is

  is not started; a bimetallic actuator element disposed in

  contact with a face of the heating element of such

  However, when this element warms up, its temperature

  re and that of said bimetallic actuator element

  an initial period of rapid growth followed by a period of slower growth, said bimetallic element being able to deform under the effect of its heating to cause the displacement of an organ

  blocking device to oppose the opening of the door

  you; and a bimetallic control element electrically connected to the other side of the heating element through an intermediate conductive element and which can

  to take, under the effect of his warming-up, a distortion

  whose effect is the reverse of the deformation

  the bimetallic actuator element.

  A device of this type is known, for example

  ple, by the Italian patent application 48 663-A / 76 of March 18, 1976. This device comprises a bimetal actuator

  and a compensation bimetal. The form and the

  bi-metal compensation are such that it is in thermal contact predominantly with air

  "ambient" contained inside the box or the enve-

  loppe of the device; its temperature follows the evolutions of the ambient temperature rather than the variations of

  the temperature of the PTC tablet which constitutes the

resistant heating.

  A serious disadvantage of this known device

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  lies in the fact that the delay time between the instant when the washing machine is stopped and

  the moment the opening of the door is authorized

  is highly variable and is all the greater as the interval of time separating the moment of interven-

  tion of the blocking device of the moment of deactivation

  This device is itself larger. It can thus occur that when the machine is put

  stopped after a period of relative

  long, we have to wait several seconds, when it's not several minutes, before we can

to open the door.

  The object of the present invention is to provide

  a device for blocking the door of a machine

  worm of the type specified at the beginning, which is exempt from the

  aforementioned above-mentioned devices.

  According to the invention, this object is achieved by means of a locking device of the aforementioned type, characterized

  in that said intermediate conductive element is sen-

  in the range of temperatures

  working elements of said heat resisting element and

  feel a shape and a thermal capacity such as the-

  said bimetallic control element heats up, under

  the effect of the heating of said heat resisting element

  ghost, with a pre-established delay in relation to the element

  bimetallic actuator, and with a dynamic that

  substantially corresponds to the slow growth dynamics of the temperature of said bimetal actuator, said delay being substantially of the same order of magnitude as said initial period of rapid temperature growth

  said heating resistor element.

  Thanks to this characteristic, the time of re-

  between the moment of shutdown of the machine and the

  washing machine and the moment when it is possible to

  der the opening of the door is made virtually constant and, in particular, independent of the time that

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  has elapsed between the intervention of the blocking device

  ge and disabling this device.

  Other features and advantages of the

  will be better understood when reading the description of

  following example of an embodiment and with reference to the accompanying drawings in which,

  FIG. 1 is a perspective view of a model

  embodiment of a device according to the invention; Figure 2 is a sectional view taken along the line II-II of Figure 1; Figures 3 and 4 are views similar to the

  Figure 1, which show the device in two

* different working conditions;

  FIG. 5 represents an enlarged scale

  tail of Figure 2; Figure 6 is a top view taken along the arrow VI of Figure 5; and Figure 7 shows a series of diagrams

  Cartesians who explain the operation of the

tif according to the invention.

  In the embodiment shown in the drawings, the device according to the invention comprises an envelope 1 insulating electricity, formed of a

  boot 2 and a covering element 3. In 4,

  diqué a member which slides relative to the casing 1 and which constitutes the lock of opening and closing of the door of a washing machine not shown, by

  example of a washing machine for household use.

  Three lamellar electrical contact members

  5, 6 and 7 are fixed inside the boot 2 and emerge

  on the outside of this boot, crossing

  made in a wall of this bolte, as shown in Figure 1. The contact 5 is intended to be connected to the power circuits of the power supply.

  washing machine; contact 6 is intended to be connected

  to one of the power line conductors

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  electric machine, while the contact 7 is

  intended to be connected to the other driver of this

Reign.

  Lamellar contact 7 is attached to the inside face

  dull of the bottom wall of the boot 2. A screw of

  8 is screwed into the contact 6, as

  Figure 2 to 5, through an opening corresponding to

  in the bottom wall of boot 2. A

  equal distances from the axis of screw 8, four columns

  parallel lines, indicated in 9, protrude from the

  internal face of the bottom wall of the box 2.

  At 10a, 10b and 10c, bimetallic control elements having substantially the shape of small rectangular blades which include

  an enlarged central part (figures 5 and 6), and which

  on the adjusting screw 8. As this is

  particularly in Figure 5, the extremes of these

  bimetallic deposits are incurred between the two

net of pairs of balusters 9.

  In 11, a metal element has been designated

  relies on the bimetallic control elements.

  Element 11 has a substantially rectangular shape

  re, with an enlarged central part, as well as the bimetallic control elements O10a, 10b and 10c. At the ends of the element 11, are formed, for example by stamping, feet lla to the right of which the element

  driver 11 relies on the bimetallic control elements

  als. The face of the conductive element 11 which is

  directed upwards presents a series of indented bosses

  as in IIb in Figures 5 and 6. -

  Element 11 is made of a conductive material

  electricity that has great heat

  and a high thermal resistance, for example

ple, it is made of steel.

  On the conductive element 11 is disposed a

  pellet 12 made of resistant material having a temperature coefficient

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  Positive Reduction (PTC). The diameter of this pellet is such that it can describe movements with a certain clearance with respect to the posts 9 (Figures 5 and 6). As will be apparent from the following, this pellet is intended to act as a heating element when

  that at the moment of putting the machine into operation

  worm, an electrical voltage is applied to this pastil-

  the. In 14, the bimetallic actuator element has been indicated

  that one end is squeezed between the lamellar contact

  7 and an inner shoulder of the box 2. This bimetallic element 14 extends above and beyond

  heating element 2 and is preferably

  traint so as to push said heating element towards

the adjusting screw 8.

  At 15, there is indicated a metal blade whose one end is fixed to the lamellar contact 7 by a

  16. This blade has a length greater than

  the bimetallic member 14; it further has a central opening 15 through which can pass

  the free end of the bimetallic element 14.

  In 17, there is shown a spring, one of which

  tremity is attached to the free end of the bimetallic element

  14 while the other end is attached to the blade 15. The latter carries a contact 15b which can

  cooperate with a corresponding contact 5a of the terminal

mellaire 5.

  Inside the boot 2, is disposed a rod 18 which can slide in a hole 19 formed in

  the boot, in a direction perpendicular to the direction

  4. The rod 18 can assume a retracted or rest position, shown in FIG.

  Figure 2, and an extension or working position, re-

  presented in Figures 3 and 4, in which it

  can engage in an opening 4a arranged in the ver-

  rou 4, to oppose the translation of this lock.

  The stem 18 has a pocket 18a in which

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  is engaged the free end of the blade 15.

  Figure 2 shows the device according to the invention

  in the idle state: the bimetallic control

  tallics are substantially flat; the blade 15 is not deformed and it keeps the rod 18 in the retracted state.

  or rest and, in addition, the contact 15b of that

  is spaced from the corresponding fixed contact 5a, worn

  lamellar contact 5. The bimetallic actuator element

  14 is curved upward.

  When the washing machine is put into action,

  that is, when connected to the feed network

  electrical current, a current flows through the lamellar contact 7, the bimetallic actuator element 14, the chip 12, the intermediate conductive element 11, the bimetallic control elements 10, the adjusting screw 8 and the lamellar contact 7. The temperature of the heating element 12 begins to grow, first of all

  quickly, then more slowly, tending to stabilize

  ser. The temperature of the bimetallic element 14 substantially increases in the same way, since it is in

  close thermal contact with heating element 12.

  In Figure 7, the higher Cartesian diagram

  represents, as a function of time t,

  the curves of a curve A which corresponds

  temperature of the bimetallic actuator element

  14. At t0, it was indicated the moment when the washing machine was started and, consequently, the moment o

  a current began to flow between the contacts la-

  mellaires 6 and 7. Between time t0 and instant t1, the

  The temperature of the bimetallic element 14 is believed to be very fast.

  as indicated by the growing branch

  of curve A of FIG. 7. The bimetallic actuator element

  the tallique 14 is thus deformed by passing from the

  tion shown in Figure 2 to that shown in Figure 3; the blade 15 is drawn upwards through the spring 14, the contacts 15b and 5a meet and the rod 18 will engage in the opening

  4a of the lock 4, which is thus retained in the position

  in which it ensures the blocking of the door of

  the washing machine in the closed position.

  Curve A of FIG. 7 is qualitatively

  indicative of the displacement sustained over time by the

  free element of the bimetallic actuator element 14,

  that this displacement is substantially proportional to the

  temperature of the bimetallic element. The level

  Si represents the position (the temperature of the bimetallic

  14) to which, under the effect of the sudden jump of

  fate 17, the blade i5 moves from the rest position of the

  Figure 2 at the working position of Figure 3. The

  time interval ti which separates the time of setting

  the washing machine of the moment of sudden jump

  that of the blade represents what is called "the time

  intervention "of the device according to the invention.

  When the time t1 has been passed, the temperature

  bimetallic actuator 14 would tend to grow more

  slowly, towards a state of thermal stabilization, com-

  this is indicated by the curve A 'drawn in phantom lines.

  in Figure 7. In fact, if the action-

  Bimetallic core 14 continued to warm up

  increasing as indicated by the curve A ', the time

  delay between shutting down the machine and

  only to wash and the moment the door lock would allow the opening of this door would

  an increasing function of the interval separating the middle

  starts the shutdown of the washing machine.

  In this way, if the washing machine were put in

  for example, at time t2, the temperature of the bimetallic

  14, which would no longer be traversed by the current,

  would follow the curve B drawn in broken lines

  in FIG. 7, and the blade 15 would return to the idle state and the door could be opened at time t3. If, on the contrary, the machine was stopped at

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  moment t'2, which is later than t2, the door can not

  to be reopened at the moment t'3, that is to say with

  a delay t'r greater than the delay tr = t3 - t2.

  In order to make the delay between the interruption of the operation of the washing machine and the time of possible reopening of the door substantially constant, the bimetallic control elements O10a, 10b, O10c are provided. These bimetallic elements are electrically and thermally coupled to the heating element 12 through the intermediate conductive element 11. This

  has a conformation and a thermal capacity

  such as temperature variations of ele-

  Bimetallic control elements 10a, 10b, 10c follow the temperature changes of the heating element and, therefore, of the bimetallic actuator element 14, with a delay substantially equal to t1-t0 and with a similar dynamic. In addition, as soon as their temperature tends to grow, the bimetallic control elements

  tend to deform (Figure 4) in an antagonistic fashion.

  the subsequent deformation suffered by the

  Bimetallic converter 14, with regard to the effect on the displacement of the rod 18. In FIG. 7, the curve C represents qualitatively, as a function of time t,

  the pace of the temperature of the bimetallic control elements

  and, consequently, the magnitude of their

  training. Since, as has been said before,

  the deformation of the bimetallic elements of

  in the opposite direction to the deformation of the bimetallic actuator element with respect to the

  displacement of the rod 18, the effect of the elements of

  Bimetallic control consists in practice of transforming

  the characteristic A-A 'of the bimetal 14 in the characteristic

  that A-A "of Figure 7, from the moment tl, the

  thermal characteristic A "of the set of elements

  bimetallic elements 14 and 10a, lo0b is practically pa-

  to the axis t and, therefore, the delay time

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  be the shutdown of the washing machine and the moment

  o the opening of the door has become possible is

of substantially constant.

  This result is obtained thanks to the fact that one adopts bimetallic control elements arranged

  facing the heating element 12 and electrically coupled

  and thermally thereto through the intermediate conductive element 11. From the thermal point of view,

  the latter corresponds substantially to a resistance (se-

  ry) and to a (parallel) capacitance and, in the electrical analogy, it therefore corresponds substantially to a group

delay type RC.

  By virtue of their size and their

  during the period in which the washing machine is running and where, consequently, the bimetallic control elements are traversed by the current, these elements tend to stabilize at a temperature intermediate between that of the PTC chip 12 and that

of the boot 2.

  Although, in the drawings and in the description

  given above, reference is made to the use of

  With three bimetallic control elements, it is obvious that a single element of this nature could be used; the use of two or more elements may be preferable to

bigger race.

  Of course, various modifications may be made by those skilled in the art to the device which

  just described as a non-limiting example.

  mitative, without departing from the scope of the invention.

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Claims (4)

R E V E N D I C A T IONS   1 - Device for blocking the door of a machine   washing machine, which comprises: a support casing (1 to 3); a heating resistor element (12) of the PTC type, supported in the casing (1 to 3) and intended to be supplied with a voltage and to be heated when the washing machine is started; a bimetallic actuator element (14) disposed in contact with a face of the heating element (12) such that when said element (12) heats up, its temperature and that of said bimetallic element (14) exhibit a period initial (t1 - to) rapid growth, followed by a longer growth period (t> t1)   said bimetallic element (14) being deformable   sea under the effect of its heating to cause the   movement of a locking member (18) intended to   be at the opening of the door; and at least one bimetallic control element (10a, 10b, 10c) electrically connected to the other side   of the heating element (12) through a conductive element   intermediary (11) and who can take, under the ef-   its heating, a deformation the effect of which   is the opposite of that of the deformation of the element   bimetallic detector (14); characterized in that said intermediate conductive element (11) is substantially indeformable in the working temperature range of said heating element (12) and has a shape and a heat capacity such that the bimetallic control element or at least one bimetallic control elements   (10a, 10b, 10c) heats up, as a result of heating up   of said heating element (12), with a delay of   established with respect to the bimetallic actuator element (14) and with a subsequent dynamic (C) which substantially corresponds to the slow growth dynamic (A ') of the temperature of said bimetallic actuator element (14); said delay being substantially of the same order of   magnitude that said initial period (tl - t0) of growth   fast temperature of said resistant element heating (12).   2 - Device according to claim 1, characterized   characterized in that said intermediate conductive element   (11) is constituted by a metal strip which presents   on one side, first bosses (lia) serving   the control element or control elements   (10a, 10b, 10c) and, on the other side,   second bosses (11b) on which the said ele- resistant heating element (12).   3 - Device according to claim 2, characterized   characterized in that said intermediate conductive element   (11) is made of a conductive material of electrical   ted, with high specific heat and high resistance thermal, for example, steel.   4 - Device according to any one of the   1 to 3, characterized in that it comprises three   bimetallic control elements (O10a, 10b, 10c) adja- cents between them.