FR2699563A1 - Device for stopping in the drum position and for quick unlocking of the access door of a horizontal drum machine. - Google Patents

Abstract

The object of the invention is a device for stopping in position a machine with a horizontal drum. This device comprises at least one locking means (22, 23) of the drum drive device, this locking means being driven into its locking position by a hooking means (24) integral either with the drum or with a part (6) of the drum drive device itself integral with the drum, when an operating means (25, 26, 27) drives the locking means from a rest position in a position where the hooking is possible, the hooking means being placed so that, when the blocking is achieved, the drum hatch is in front of the access opening of the machine. The invention applies in particular to washing and / or drying machines.

Description

i Stopping device in drum position and quick unlocking

  The invention relates to a device for stopping in position and for rapidly unlocking the access door of a horizontal drum machine. The present invention also relates to a machine for wash and

  / or to dry the laundry provided with such a device.

  A washing machine and / or tumble dryer usually comprises a perforated drum containing the laundry and rotating inside a tub

  intended to retain the washing or rinsing water.

  The drum is usually driven by a motor placed under the tank, the transmission of movement being carried out via a belt and two pulleys respectively fixed

  on the motor shaft and the drum axis outside the tank.

  In washing machines with access from above, the access door of the body gives access to the sealed door of the tank which in turn overlooks the drum, the latter being itself provided with a

access hatch.

  During certain operating phases of the machine, the drum can rotate at very high speeds, which can exceed 800 rpm. For obvious safety reasons, an automatic locking device is provided for the access door of the machine. bodywork The user does not have access to the interior of the machine as long as a danger persists. The locking device can operate either during the entire wash cycle or only during high speed phases. In this case, the locking device is connected to the electromechanical programmer or to the device

electronic if necessary.

  The lock of the locking device is often of the thermal type, because of the low price of such a mechanism This is for example a bi-Mame or wax lock When the thermal element is energized, its expansion causes the bolt bolt to move, which will block the opening of the access door of the bodywork. The disadvantage of this type of lock is its high inertia Indeed, appreciable time is required for the heating of the thermal element and even more for its cooling This cooling time can range from 90 to 120 seconds depending in particular the nature of the thermal element and the temperature inside the bodywork During this lapse of time, access to the inside of the machine

not possible.

  This can be a nuisance for the user, whether he wants to add laundry during the wash cycle or simply remove it

immediately at the end of the cycle.

  On the other hand, when accessing the drum, the hatch of it

  is rarely found in front of the opening of the tank door.

  The user is then obliged to turn the drum by hand to access this hatch This operation can be painful because of the large unbalance created by the wet cloth or because of the laundry that can make the surface of the drum extremely slippery when the machine is open in full cycle In addition, there is a risk of injury due to the rough surface condition due to perforations of the drum. Currently, various devices are used to position the drum, but these devices are unsatisfactory because they are mechanically complex and therefore expensive and unreliable In addition, some, if they position the drum, does not block rotation after positioning , leaving him at the mercy of an unbalance of laundry that can rotate it to an unwanted position Others still perform a positioning at the end of washing, forcing the user to manually turn the drum s' he wants to access it

during the wash cycle.

  The present invention aims at reducing the drawbacks mentioned above.

  One of the aims of the invention is to propose a device, mechanically simple and requiring few parts, stopping in position of a horizontal drum machine allowing not only to perform the alignment of the door of the drum and the door. when the machine stops, whether it is a stop of end of washing or a stop commanded by the user, but also allowing to unlock quickly the door of access of the bodywork of the machine during this stop, while guaranteeing the safety of said user It should be noted that the stop device in position can be implemented without being used with a quick release The combination of the two functions, stop in position and quick unlocking, allows

  however, an appreciable reduction in the cost price.

  The stop in position of the drum with or without quick release of the access door of the bodywork can be carried out at any time during the operation of the apparatus, in particular

during the spinning phases.

  Another advantage of the invention is that it makes it possible to bring the drum into the desired position smoothly, thus limiting the

constraints on the parts.

  The invention therefore relates to a stop device in position of a horizontal drum machine characterized in that it comprises at least one locking means of the drive device of the drum, this locking means being brought into its blocking position by a fastening means secured to the drum or a part of the drive device of the drum itself secured to the drum, when an actuating means causes the locking means of a rest position to a position o the attachment is possible, the attachment means being placed so that when the locking is achieved, the drum door is in front of the access opening of

the machine.

  According to a particular embodiment of the invention, the locking means is connected to the bolt of the automatic door lock of the bodywork so that the latter unlocks the door when

  the locking means enters the blocking position.

  The present invention will be better understood and others

  advantages will appear on reading the detailed description of a mode

  particular embodiment of the device, taken by way of nonlimiting example and illustrated by the accompanying drawings, in which: Figure 1 shows a general schematic view, in cross section relative to the axis of the drum, of a machine washing and / or drying laundry comprising an exemplary embodiment of the device according to the invention, Figure 2 schematically shows the connections of the numerical control module of the machine with the microswitches and the control of the operating means of the locking means FIG. 3 diagrammatically represents an exemplary embodiment of the device for stopping in position and unlocking in its rest position, FIG. 4 schematically represents the same embodiment of the device according to the invention in a so-called approach position. 5, shows schematically the exemplary embodiment of the device according to the invention when the arr in position and unlocking have been performed, Figure 6 shows a means for improving the holding of the device in the locking position according to a further embodiment of the invention, when the device is at rest, Figure 7 shows what same means when the device is in the blocking position, Figure 8 shows part of this means in more detail. To simplify the disclosure of the invention, only the application to a washing machine and / or drying is described below It is within the reach of the skilled person, using its ordinary capabilities, adapt the

  device according to the invention to any horizontal drum machine.

  FIG. 1 shows a washing machine and / or dryer having a body 1, the access to the interior of the machine being via an access door 2 This access door is provided on the top of the machine. the machine in the case of a machine with access from above as shown A pulley 3 fixed to the motor shaft 4 transmits, through a belt 5 the rotation of said motor 4 pulley

  6 driving the drum 7 horizontal axis.

  The machine further comprises a tank 8 provided with an access door 9 Inside the tank 8 rotates a drum 7, also provided with an access door 12 Said drum 7 is rotated by the pulley 6, the latter being fixed in a known manner on the axis of the drum 7 outside the tank 8 The collar 10 seals

  between the access door 9 of the tank 8 and the tank itself.

  A control panel 11 allows the user to make

operate the machine.

  The machine also comprises a manual unlocking button 13 of the access door 2 of the bodywork. In FIG. 1, this button 13 is located on the front face of the bodywork, but it can be placed on the control panel 11. automatic safety lock, the latch engages in the finger 15 fixed to the access door 2, is also provided and will be described in more detail later A compression spring 14 raises the access door 2

  when the latter is not retained by any lock.

  FIG. 2 represents certain connections of the digital module 16 for controlling the operation of the washing and / or drying machine. One of the roles of said digital module 16 is, inter alia, to control the speed and direction of rotation of the motor 4 The module 16 receives in return the data from the tachometer 17,

  thus allowing a regulation of said speed.

  A micro-security switch 18 cuts off the general power supply

  of the machine when the access door 2 of the body opens.

  According to the invention, the washing and / or drying machine comprises a device for stopping in position and for quick unlocking of the access door The position of said device relative to the whole machine is shown schematically in FIG. figure 1 Figures 3 to 5

  represent this same device in more detail.

  A support plate 21 of the device for stopping in position and for quick release is fixed in known manner on the tank 8 or on any fixed element with respect to the axis of the tank 8. The device itself comprises a shaped element 22. wedge bearing a hook 23 so that a lug 24, the position of which is described later, comes into engagement with the hook, thus causing the wedge 22 with its guide rod 25 so that said wedge 22 is jammed between the pulley 6 and the belt 5 when the motor 4 rotates in the preferred direction and the shim 22 has been previously put in the approach position. The shim 22 has a substantially beveled shape It is flat on the side coming to press against the belt 5 so as to have a large contact surface and fits the radius of curvature of the pulley 6 of the opposite side This does not prejudge in any way of the surface state of the wedge, which may comprise means which increase the friction for example between itself and the belt 5 or the pulley 6 The wedge 22 may in particular have a rough surface or even adapt to the sculptures of the belt 5 if necessary Advantageously, the wedge 22 can be made of a flexible material, thus making it possible to reduce the

  stresses on the belt 5 and the wedge 22.

  The hook 23 is either an insert and fixed in known manner on the shim 22, or is integral therewith. The wedge 22 and its hook 23 are supported by a guide rod 25 which fits into the spool 26 fixed on the support plate 21 The guide rod 25 comprises a magnetic core 27 allowing a translation in the direction of the axis of the rod 25 when the coil 26 is powered by

  via the connections 28 and 29 connected to the digital module 16.

  The guide rod 25 further comprises a stop 30 intended to hold said rod 25 so that the magnetic core 27 is in a good position relative to the coil 26 when the device is in the rest position In a particular embodiment variant a return spring 31 returns the guide rod 25 and therefore the shim 22 in the rest position when the machine is restarted.

  to wash after a stop in position has been made.

  According to an alternative embodiment, the guiding and translation means are dissociated: rails or a guide rod are then provided, the latter being distinct from the element carrying the core.

  magnetic 27, this element can of course also be a rod.

  As shown in particular in Figures 3 to 5, the machine comprises a manual release button 13 of the access door 2 of the body The button 13 has a hook 32 latching on a stop 33 of the door 2 of bodywork De moreover, the manual unlocking button 13 actuates a microswitch 19 connected to the digital module 16 When the user depresses the button 13 during washing, the change of state of the microswitch 19 causes at the level of the digital module 16 the control of the stopping in position of the machine in the manner described later Advantageously, a pulse given to the button 13 is sufficient to control the stop position According to another embodiment of the invention, the corresponding pulse can also be given via a stop button, not shown, the control panel, the interface between the stop button and the digital module is the same way as for the worm button manual rusting 13, by associating the stop button with a microswitch connected to the digital module 16, said dashboard stop button may also have the

  manual unlock function of the access door of the bodywork.

  The access door 2 of the bodywork can also be locked automatically by means of an automatic lock whose bolt 34 is inserted into an opening 35 of the finger 15 of the door 2 of the body. The automatic lock can be actuated either by a In this case, and as shown in FIGS. 3 to 5, the bolt 34 is connected to the guide rod 25 by means of the stop device. The cable 36 can slide in an opening in a support 38 fixed to the guide rod 25 A stop 39 attached to the end of the cable adjusts the height of the guide rod 25 from which said rod pulls on the cable 36 This height is advantageously adjusted so that the guide rod 25 pulls the cable 36 at the earliest time when the pin 24 pulls on the assembly stem The course of the cable 36 is, on the other hand, advantageously calculated so that the bolt 34 is disengaged from the opening 35 at the latest when the shim 22 is in its locking position. the positioned stop device is at rest, a compression spring 40 bearing on a stop 41 forces the bolt 34 to enter the opening 35, thus locking the door 2 of the bodywork.

  return the hold 22 to its rest position.

  The device is in the rest position when a wash cycle

  is in progress Figure 3 shows the device in this configuration.

  The access door 2 of the bodywork is then kept closed by the manual lock 13 and the bolt 34, and the shim 22 and its hook 23 are in a position such that they do not interfere with the rotation of the pulley 6.

  direction and the speed of rotation of the drum 7 may be arbitrary.

  A preferred direction of rotation of the drum 7 is defined and a contrary direction, the preferred direction being the opposite direction to the needles of a

  shows with respect to Figures 1 and 3 to 5 (Si direction).

  A stop in position is controlled under two circumstances: either when the user sends a corresponding pulse by pressing the manual release button 13 or a stop button on the

  control panel 11, that is when the washing of the laundry is finished.

  In the latter case, the necessary control can for example be given via a contact of the electromechanical programmer. At first, the digital module 16 controls the unposted stop of the machine This can be achieved by cutting the power supply of the motor 4 When the speed of the motor 4 is zero, the digital module 16 controls a rotation of the motor 4 to low speed, corresponding for example to a rotation of the drum at 30 rpm, in the preferred direction Si At the same time, the digital module 16 controls the energization of the coil 26 The translation of the core 27 and thus the rod of guidance 25 pushes the wedge 22 and its hook 23 in said approaching position, this position being such that the lug 24 integral with the pulley 6 engages in the hook 23, driving the latter in its movement. The means of maneuvering the locking means therefore comprises, in the present embodiment, the coil 26, the core 27 and the guide rod 25 The so-called approach position is shown in Figure 4 The wedge 22 then comes stuck gradually between the pulley 6 and the belt 5, the speed and the inertia of the drum 7 and the pulley 6 being such that the engagement of the wedge 22 is sufficient to firstly block the pulley 6 and therefore the drum 7 in rotation in the preferred direction If, and secondly to prevent a rotation of the drum 7 in the opposite direction because of a possible unbalance of laundry, once the power of the motor 4 cut The position of the pin 24 on the pulley 6 is such that when the latter and the belt 5 are blocked, the access door 12 of the drum 7 is in front of the door 9 of the tank L'ergot

  24 is advantageously placed on one of the faces of the pulley 6.

  When the shim 22 begins to engage in its locking position, the rod 25 pulls on the cable 36 through the support 38, secured to the guide rod 25, which is placed against the stop 39. The bolt 34 releases the finger 15 The compression spring 14 pushes the access door 2 of the bodywork, allowing the user to access the interior of the machine At the same time, the safety micro-switch 18 cuts off the power supply general machine, and more

  particularly that of the engine 4.

  It should be noted that the hook 32 of the manual unlocking button 13 must be released from the stop 33 so that the access door 2 of the bodywork opens. This is not a problem when the button 13 is a bistable button, because in this case, the hook

  32 remains clear of the stop 33 even if the user releases the button.

  If it is a monostable push button (ie a button that returns to its original position as soon as it is released), the user must hold it pressed until it stop in position of

  drum for the access door 2 of the body opens.

  Advantageously, provision is made in the latter case, according to a method of

  particular embodiment, a means for detecting the position of the drum.

  Said means is connected to the digital module 16, which processes the information that emanates from it. When the drum 7 is correctly positioned and its speed is zero, the user is visually informed via a control panel element. Such a device prevents the user from holding the button 13 pressed until

stopping in position of the drum.

  As long as the drum is not in the desired position (because of excessive unbalance of laundry creating a sufficient moment to unlock the wedge 22 for example), the stop blocking cycle in position is restarted, possibly preceded of an unbalance elimination phase, the latter not being part of the present invention Advantageously, if after a certain number of tests, for example 5 tests, stopping in position has still not been possible. realized, the latter information is also displayed, the access door 2 can then be unlocked by manual means whose implementation is obvious to those skilled in the art The engine power is also cut in this case. The means for detecting the position of the drum may, for example, comprise a reflective label placed on the pulley 6 and a light-emitting diode and a sensor placed in front of the pulley. Other means can obviously be used, such as sensors. Reed or Hall effect associated with a permanent magnet

  conveniently placed on the pulley 6.

  According to a particular embodiment of the invention, the latter comprises a not shown current cutoff device other than that controlled by the safety microswitch 18, characterized in that it cuts off the power supply of the motor 4 and the coil 26 when an inadvertent rise in the current in the rotor or the stator of the motor 4 is detected while the rotational speed of said motor is zero This additional safety device may be necessary in the case where the bolt 34 remains locked in the opening 35 while the rotation of the drum 7 is blocked but the motor 4 is still powered, the safety microswitch 19 only being triggered when opening the access door 2 of the bodywork will thus avoid damaging the wedge 22 or the belt 5 The realization of such a safety device is to

the scope of the skilled person.

  The digital module can also be used to detect a blocking of the rotor If, for example, a rotation of the motor has been commanded by said module 16, it will be sufficient to check the correct execution of this command by monitoring the tachometer. Such a monitoring can easily be programmed. If you want to know if the motor is blocked when no rotation command has been started,

  it will be sufficient to carry out this command beforehand.

  The machine will be turned back on once the safety microswitch 19 is closed, that is to say once the access door 2 of the

body closed.

  The machine is constituted so that when restarting, the drum 7 turns first in the opposite direction to the preferential direction If the digital module 16 is programmed accordingly This has the effect of unlocking the wedge 22, of disengage the lug 24 of the hook 23, thereby allowing the wedge 22 and the hook 23 to resume their rest position, either by simple gravity or by means of

  compression springs 31 and / or 40.

  According to one embodiment, means are provided for increasing the acute angle between the hook 23 and the wedge 22 when the locking means is placed in the approach position, so as to facilitate hooking of the hook 23 by the 24 at this time, while avoiding inadvertent snapping at other times In addition, there is provided a damper on the one hand to damp the mechanical shocks suffered during an approach position setting, on the other hand for fold the hook 23 when the device returns to its rest position This embodiment has the advantage of increasing the relative displacement of the hook 23 for a translation length of the guide rod 25 identical to

  that of the first embodiment.

  When the device is at rest, the hook 23 is folded against the shim 22 According to this embodiment, the hook 23 is bent and is provided at the elbow of an axis which is housed in a corresponding location not shown in the hold 22, so that the hook 23 can pivot about its axis while being locked in translation parallel to this axis The hook 23 has beyond its elbow an arm, the side forming with the other arm an acute angle This damper is such that the damping is compression along its length when the hook 23 pivots about its axis in the direction of the needles.

of a watch.

  The damper may for example be a spring or a piece of

  a compressible elastic material.

  The side of the arm opposite the side coming to rest against the damper is rounded, so that a stop pivots the hook 23 by sliding along this rounded side when the shim 22 is translated to its position d The stop is fixed in relation to

the tank 8.

  In the rest position, the damper has a maximum elongation The acute angle between the hook arm 23 o will catch the lug 24 and the side of the shim 22 coming to press against the pulley 1 then has its minimum opening When the device is in the approach position, the opening of the angle is enlarged, the stop pressing on the rounded side of the arm, while the damper begins to compress Once the approach position reached, the hook 23 awaits the arrival of the pin 24 The shock due to the contact between the hook 23 and the pin 24 is at least partially absorbed by the damper Everything is

  then passes as in the first embodiment.

  According to an embodiment represented in FIGS. 6 to 8, means are provided for improving the maintenance of the device, and by

  consequent drum, in blocking position.

  These means of improvement of maintenance comprise a retractable element 47,48 exerting, on a lamella 46 integral with the stem-shim assembly 25, 22 and having at least one hollow, a force such that, when the device is in the position of blocking and that the head 48 of the retractable element is positioned in a recess of the blade 46, the device is held in position despite a possible imbalance of laundry to

inside the drum 7.

  FIGS. 6, 7 and 8 represent a part of the device according to the invention accompanied by said means for improving holding when said device is respectively in the rest or blocking position. According to this embodiment, a lamella 46 in the form of a S whose vertical axis is parallel to the axis of translation of the shim 22 and its guide rod 25 The blade 46 is integral with the wedge-rod assembly and may for example consist of an extension of the support 38, as FIGS. 6 and 7 show that when the blade 46 moves at the same time as the guide rod 25, it comes to rub against a locking rod 47 whose axis is

  advantageously perpendicular to the axis of translation of said rod 47.

  The latter is provided with a head 48 with a rounded end and a ring 49 on which a spring 50 bears. The assembly is held between two stops 51 and 52, fixed on the support plate 21, as illustrated by FIG. 8, so as to allow the rod 47 to translate between two positions, one being reached when the ring bears against the stop 52, the other being reached when the spring 50 is compressed.

  first position is the rest position. When the shim 22 and its guide rod 25 are driven towards the

  blocking position, the lamella 46 comes into contact with the head 48, which retracts under the effect of the force exerted. The head 48 then follows the curves of the lamella 46 The length of this lamella 46 is calculated so that the head 48 comes to be placed in the hollow formed by the lower loop of the S at the very moment when the shim 22 is in the locked position The stiffness of the spring 50 is calculated so as to oppose effectively a possible fallout of the wedge due an exceptionally large unbalance of laundry while allowing an unlocking of the head 48 under the effect of the engine torque when restarting

  of the set after a stop in position has taken place.

  According to a variant of the preceding example, the head 48 is immobile

  while the lamella 46 is flexible.

  According to an embodiment not shown, the operating means which places the shim 22 in the approach position does not perform a translation, but a rotation or the combination of a rotation and

of a translation.

  According to another embodiment, the stop device

  position is used without the quick unlocking of the access door.

  According to another embodiment not shown, the fastening means integral with the drum 7 or a part of the device

  driving the drum, such as the pulley 6, is a hook.

  According to a not shown embodiment, the device for stopping in position and for quick unlocking of the access door is used with a horizontal drum apparatus without a sealed tank. In this case, the belt is placed directly on the drum. hooking

  is then advantageously fixed on the cylindrical portion of the drum.

Claims (18)

claims   1 stop device in position of a horizontal drum machine characterized in that it comprises at least one blocking means (22,23) of the drum driving device, this locking means being driven into its position of locking by a fastening means (24) integral with either the drum (7) or a part of the drum driving device itself secured to the drum, when an operating means (25,26,27) causes the locking means of a rest position in a position where the attachment is possible, the attachment means being placed so that, when the locking is achieved, the drum door is in front of the access opening of the machine.   2 Device according to claim 1, characterized in that the locking means is constituted by a wedge-shaped element (22) which is placed between the drive belt (5) of the drum and the drum (7) or the workpiece (6) the drive device itself secured to the drum according to that the belt is placed directly on the drum or on said piece.   3 Device according to one of claims 1 or 2 characterized   in that the locking means has a hook (23) positioned so that it can be driven by the hooking means (24) integral with the drum (7) or the workpiece (6), when the locking means is set   in the approach position by the maneuvering means.   4 Device according to one of claims 1 to 3, characterized   in that the fastening means integral with either the drum (7) or the   piece (6) is a lug (24) or a hook.   Device according to one of the preceding claims,   characterized in that when the drum (7) is enclosed within a sealed tank (8) and is secured by its axis with a pulley (6) driven by a belt (5), the hooking means is placed on a next to the pulley (6).   Device according to one of Claims 1 to 4, characterized   in that in the washing and / or drying machines where the belt (5) directly drives the drum (7), the hooking means is placed on   the cylindrical portion of the drum (7).   7 Device according to one of the preceding claims,   characterized in that the operating means is a device for translating a guide rod (25) integral with the shim (22) and its hook (23).   8 Device according to claim 7, characterized in that the translating device comprises a magnetic core (27) fixed on the guide rod (25) and a magnetic coil (26) which when energized performs the desired translation and by the axis of which passes the   guide rod (25) and the core (27).   9 Device according to one of the preceding claims,   characterized in that the guiding and translating functions are not   not made by the same element.   Device according to one of the preceding claims,   characterized in that a stopping device in position is associated with a device for rapidly unlocking the access door (2) of the body which unlocks the automatic safety lock of   the device when or at the same time as the positioned stop is performed.   11 Device according to claim 10, characterized in that the automatic safety lock of the apparatus has a bolt (34) connected by a cable (36) to the guide rod (25) of the shim (22), the race of said cable (36) being adjusted so that the cable (36) pulls on the bolt (34) at the earliest when the lug (24) engages in the hook (23) and so that the lock is fully unlocked when the hold (22) is in its blocking position.   Device according to one of the preceding claims,   characterized in that the stop in position is controlled by means of a push button (13) connected to a microswitch (19) whose state is   collected by the digital control module (16).   13 Device according to one of the preceding claims,   characterized in that the stop in position is controlled by the digital module (16) or directly by the programmer at the end of the washing and / or drying the laundry.   Device according to one of the preceding claims,   characterized in that before the wedge-hook assembly (22,23) is in the approach position, the motor (4) rotates the drum (7) at a low   speed in the preferred direction (Si).   Device according to one of the preceding claims,   characterized in that the access door (2) of the body of the horizontal drum machine is connected to a safety microswitch (19) which cuts off the supply of the apparatus when the access door (2) is opened. Device according to claim 15, characterized in that the horizontal drum machine comprises a drum-locking sensor, and in that the apparatus comprises means for cutting off the supply of the motor (4) in this case if it does not was not done by the safety microswitch (19).   Device according to Claim 16, characterized in that this detection is carried out when an abnormal rise in the current in the rotor or stator of the motor occurs or when the digital module (16) detects by means of the tachometer (17) a zero or insufficient rotation while a rotation of the motor has been ordered.   Device according to one of the preceding claims,   characterized in that when the machine is restarted, the drum first turns in the opposite direction (52) of the preferred direction,   so that the lug (24) disengages from the hook (23).   Device according to one of the preceding claims,   characterized in that when restarting the machine, the shim (22) and its hook (23) are returned to their rest position by   gravity or at least one spring (31,40).   Device according to one of the preceding claims,   characterized in that means are provided for pivoting the hook (23) so as to increase the opening of the receiving angle of   the lug (24) when the device is placed in the approach position.   21 Apparatus according to claim 20, characterized in that said pivoting means comprise a damper acting both as a shock absorber and a return spring folding the   hook (23) when the device returns to the rest position.   Device according to one of the preceding claims,   characterized in that means are provided to improve the holding of the device and therefore the drum when they are in the locking position. 23 Apparatus according to claim 22, characterized in that said means for improving retention comprise a retractable element (47,48) exerting on a lamella (46) integral with the stem-shim assembly (25,22) and comprising at least one recess, a force such that, when the device is in the locking position and the head (48) of the retractable element is positioned in a recess of the lamella (46), the device is held in position despite a possible unbalance of laundry at the inside of the drum (7).   24 Device according to one of claims 22 and 23,   characterized in that the holding force exerted by the retractable element (47,48) is calculated to allow the driving torque   disengaging the head (48) from the hollow of the lamella (46) during a restart of the machine.