EP2812476B1

EP2812476B1 - A locking device comprising a moving element, particularly of a washing machine, and associated method

Info

Publication number: EP2812476B1
Application number: EP12718683.1A
Authority: EP
Inventors: André MAZIÈRE
Original assignee: Electrolux Laundry Systems France SNC
Current assignee: Electrolux Laundry Systems France SNC
Priority date: 2012-02-09
Filing date: 2012-05-07
Publication date: 2021-05-26
Anticipated expiration: 2032-05-07
Also published as: WO2013117244A1; SI2812476T1; EP2812476A1; ES2875457T3

Description

TECHNICAL FIELD

The present invention relates to a locking device comprising a moving element, particularly a moving element of a washing machine. The invention further relates to a washing machine comprising such a locking device and an associated method for locking or releasing said moving element.
Document DE 100 03 474 A1 discloses a washing machine with a locking system for a drum. The locking system comprises a locking pin on a lever. The lever and the locking pin are arranged to be pressed against the peripheral surface of the drum. When the locking pin reaches an aperture on the drum the locking pin locks the drum.
Document EP1798323A1 discloses a washing machine and/or drier containing a washing chamber surrounding its drum which has a horizontal axle rotated by a pulley driven by a motor and belt. To stop the drum in the required position for loading/unloading through flaps the machine has an indexing pin that engages with a notch in the pulley. The drum locking mechanism also has a draw pin that is linked to the indexing pin and slides along a bar on the pulley to move the indexing pin between its two operating positions. The indexing pin interacts in turn with a detector controlling the drum drive motor.
Document US 5 438 766 A discloses a rotating drum tumbler for loosening damp, entangled cloths or sheets which includes a frame, a cylindrical drum rotatably supported by the frame for rotation about a horizontal axis thereof and having an opening in each of the opposite ends thereof, and drive means for rotating the drum, and which is characterized in that a conveyer is secured within the drum for rotation therewith and operable to discharge the loosened cloths or sheets placed thereon through one of the openings when the drum is maintained in a predetermined position with the conveyer being horizontally positioned.
Document JP 2004 344463 A discloses a washing machine that rotates a rotor by means of a driving system using both magnetic attraction and repulsion forces between the rotor and a stator of a drum motor. When a magnet attached to the rotor passes through a hole IC board, and a detection signal for indicating the locked position is obtained, the driving system is switched into another one using only the magnetic repulsion force between the rotor and the stator so as to bring the rotor to a temporary stop. Then, the rotor begins to gradually rotate in the reverse direction at a slow speed. When another detection signal is obtained, an engagement pin is advanced from a drum locking drive unit to be engaged with a groove part to lock the drum.
Document FR 2 751 669A1 discloses a top loading washing or drying machine with automatic opening and closing of the drum. The machine comprises at least one drum equipped with a sliding door, means for controlling the direction of rotation of the drum and hooking means for hooking and immobilizing the door relative to the machine, the drum continuing to rotate, opening or closing depending on the direction of rotation of the drum.

BACKGROUND ART

It is to be noted that in the present application the expression "washing machine" may as well indicate a "simple" washing machine (i.e. a washing machine which can only wash and rinse the laundry) and a washing-drying machine (i.e. a washing machine which can also dry the laundry), both of the front-loading type and of the top-loading type.
In the operation of loading and/or unloading items in a washing machine, it is convenient for the drum to be stopped, at the end of a finished wash cycle or at the beginning of a new wash cycle, in a given position to facilitate loading and/or unloading operations.
A known method to lock the drum in a predetermined position uses a system formed by a friction disk and paddles. The paddles are adapted to press on the friction disk, mounted on the drum, using springs. Energy, electricity or air pressure for example, has to be applied to release the paddles from the friction disk, thus allowing the drum to rotate freely. When energy is removed, the springs press the paddles and stop the drum by friction effect so that the drum remains in a predetermined position until energy is applied again. Thus, the system acts as a brake when no energy is applied.
This known method exhibits two major drawbacks. Firstly, in case of a sudden power failure, during washing for example, the brake is activated and the drum stopped with high friction forces and wear particles removed from the paddles. Secondly, such a system acting as a brake needs periodic maintenance.
Another known method is based on the principle of locking the shaft of the motor of a washing machine using an integrated brake on the rotor of the motor. This principle is quite similar to the previous one except that it needs a smaller brake disk but it exhibits the same drawbacks. Moreover, the safety level is low because it relies on the belt to do the junction between the shaft of the motor and the drum.
Other methods of the prior art use for example the principle of locking the drum thanks to a mechanical system having a finger going through a hole or the principle of manually locking the drum using a side mechanical-operated latch. These solutions are not adequate in terms of efficiency and reliability.
US 2003/0172688 , and also EP 0 347 393 , US 2005/0126230 and WO 2006/037799 , disclose examples of locking devices for stopping the rotation of a drum of a washing machine. These devices mostly use a first element located on a rotor part of the washing machine cooperating with a second element located on a stator part of the washing machine. The cooperation of the first and second elements enables locking the drum in a predetermined position. The interaction between these two elements is not optimal and they might sometimes not allow an immediate, reliable and efficient blocking of the drum. The blocking and/or unblocking of the drum may also be difficult to implement with such locking devices. In particular, US 2003/0172688 discloses a locking pin on a rotor part of a washing machine having a width substantially similar to the width of a fixed form located on a stator part of the washing machine. Thus, the interaction between the locking pin and the fixed form causes important friction between the two elements, and especially between the locking pin and the two side walls of the fixed form. The appearance of such a friction phenomenon has major drawbacks since the drum of the washing machine may have a considerable weight when loaded, and the insertion and/or withdrawal of the locking pin with friction may require the use of a very strong motor or magnet, for example.

DISCLOSURE OF THE INVENTION

Accordingly, there exists a need for providing an alternative locking device for a moving element, particularly a moving element of a washing machine. There also exists a need for having a more efficient and reliable locking device and easy to implement.
The invention aims to substantially satisfy these needs and to obviate the drawbacks mentioned above related to embodiments of the prior art.
In one aspect, the invention relates to a locking device comprising a moving element, particularly a moving element of a washing machine, for example a drum of a washing machine or a moving member which rotates integrally with the drum, comprising :

a locking arm slidable between an outward position and a retracted position, said locking arm being adapted to be fitted into one aperture formed on the moving element, particularly on the peripheral circumference of the moving element, to stop the moving element at a given position, particularly a loading/unloading position of the drum,
operating means for the locking arm which are able to move the locking arm from said retracted position to said outward position for locking the moving element and vice versa for releasing the moving element,
detection means acting on said operating means to allow movement of said locking arm,

The present invention may show several advantages compared to the solutions of the prior art. For example, the perceived safety level and ergonomics of the device may be increased from a user point of view. No maintenance may be needed essentially because no wear parts and no heavy contact are present. The invention may provide high reliability because very few moving parts are needed. Moreover, the invention provides a safe locking device enabling the drum to remain in position even without power.
The locking device of the invention may further comprise one or more of the following features, considered singly or in any technically feasible combination.
The detection means comprises according to the present invention a first sensor and a second sensor both intended to face the aperture of the moving element.
The first and second sensors may be of the same type and may have the same features, e.g. the same dimensions or technical features.
The distance between the first sensor and the second sensor, and the width of the locking arm, are according to the present invention less than the width, in particular the circumferential width, of the aperture. By "less", it is meant strictly less. In particular, the distance between the operating means and/or the width of the locking arm is not substantially equal to the width of the aperture.
For example, the distance between the operating means and/or the width of the locking arm may be equal to 90 %, better 80 %, better 70 %, of the width of the aperture. The aperture may be so large that the locking arm does not fill up the whole aperture. Therefore, the invention may allow avoiding the insertion and/or withdrawal of the locking arm with friction and the use of a strong motor or magnet to insert and/or retract the locking arm. Thus, the blocking and/or unblocking of the moving element is easier to implement.
The detection means may be configured to detect at least one relative positioning of the detection means with respect to the aperture enabling positioning the locking arm in the outward position or the retracted position with no contact between the locking arm and the aperture, in particular the side walls or borders of the aperture. Thus, the use of the detection means, in particular the first and second sensors, makes it possible to know when the locking arm is inserted and/or withdrawn without causing friction against the aperture.
The first and second sensors may be position sensors.
The at least one relative positioning of the detection means with respect to the aperture may correspond to a position in which at least one of the first and second sensors face the aperture and/or a position in which both the first and second sensors face the aperture.
In particular, the at least one relative positioning of the detection means with respect to the aperture may be a position in which both the first and second sensors face the aperture, the first sensor and the second sensor being in particular respectively located at equal distance from the first border and the second border of the aperture, and the detection means may be arranged to act on the operating means to allow positioning the locking arm in the outward position or the retracted position while the detection means and the aperture are in said relative positioning.
The first and second sensors may be located at an end of the locking device, in particular an end located close to the moving element. The first and second sensors may overlap the moving element.
The base of the locking device may be mounted on a fixed supporting structure of a system carrying the moving element, in particular a washing machine.
The distance between the base of the locking device, situated on a supporting structure, and the first and second sensors may be higher than the distance between the base of the locking device and the locking arm. Thus, the locking arm may engage into the aperture of the moving element while the first and second sensors may overlap the moving element.
The locking arm may comprise separate tips, particularly three separate tips, intended to be fitted into said aperture formed on the moving element. For example, the locking arm may comprise a middle tip and two side tips located on either side of the middle tip, said two side tips being able to come into contact with the moving element, particularly the aperture of the moving element. The middle tip may be larger than the two side tips. At least the middle tip may be convergent in the direction of the moving element. The two side tips may converge towards the middle tip.
The tips, particularly the two side tips, may be flexible. Having flexible tips may advantageously allow a dumping effect of the moving element stop. This may also provide high perceived quality compared to a metal-on-metal contact.
The outward position of the locking arm corresponds to a position in which the locking arm, in particular the tips of the locking arm, is fitted into the aperture of the moving element while the retracted position corresponds to a position in which the locking arm is not present in the aperture, the tips of the locking arm having particularly no contact with the aperture.
The operating means may comprise a torque motor capable of moving the locking arm from the retracted position to the outward position and vice versa, especially by receiving signals from the detection means.
The operating means may also comprise electronics capable of reading the state of the detection means, especially the state of the first and second sensors.
In another aspect, the invention relates to a washing machine, particularly a laundry washing machine, comprising :

a processing tub,
a drum mounted rotatably in the processing tub,
possibly, at least one moving member which rotates integrally with the drum,

The drum may be connected to a first shaft. The at least one moving member may be a pulley which is fixed at one end of the first shaft of said drum and connected by means of a transmission belt to a second shaft of an electric motor for moving the drum. The pulley may comprise the aperture.
The aperture may be an open window or a hole (or gap) formed on the peripheral circumference of the at least one moving member, in particular the pulley.
The detection means, comprising the first and second sensors, may be located close to the drum or the at least one moving member, especially the pulley.
In yet another aspect, the invention relates to a method for locking or releasing a moving element, in particular a drum of a washing machine or a moving member which rotates integrally with the drum, comprising an aperture, characterized by the fact that the method is implemented by means of a locking device as previously defined and by the fact that it comprises the step of moving the locking arm from the retracted position to the outward position or vice versa when the detection means detect the at least one relative positioning of the detection means with respect to the aperture formed on the moving element.
The method may particularly comprise the step of moving the locking arm from the retracted position to the outward position or vice versa when the detection means, comprising the first sensor and the second sensor, face the aperture and are located at equal distance from the first and second borders of the aperture. The locking arm may be at equal distance from the first and second borders of the aperture. In other words, the locking arm or the detection means may be centered relative to the aperture. There may be no contact between the locking arm and the first and second borders of the aperture.
The steps for locking the moving element may be successively as follows :

letting the moving element rotate until a relative positioning of the detection means with respect to the aperture is reached in which the detection means, in particular both the first sensor and the second sensor, face the aperture, the detection means being particularly centered relative to the aperture,
moving the locking arm from the retracted position to the outward position to lock (or stop) the moving element.

The steps for releasing the moving element may be successively as follows :

rotating the moving element until a relative positioning of the detection means with respect to the aperture is reached in which the locking arm has no contact with the first and second borders of the aperture, the locking arm being particularly centered relative to the aperture,
moving the locking arm from the outward position to the retracted position to release the moving element.

The previous step of rotating the moving element may be preceded by a step in which the detection means, in particular the first sensor and/or the second sensor, detect whether the locking arm is in contact with the first border or the second border of the aperture in order to determine the direction of rotation of the moving element. Therefore, the release or unlocking of the moving element may be preceded by a step of sensing the individual state of each sensor, in particular their position relative to the aperture, to decide in which direction the moving element should rotate.
Assuming that the first sensor is the first one and that the second sensor is the second one in the clockwise direction, the direction of rotation of the moving element may be the clockwise direction if the second sensor detects a contact between the locking arm and the second border of the aperture or the counterclockwise direction if the first sensor detects a contact between the locking arm and the first border of the aperture.
The washing machine and the method of the invention may comprise one or several features mentioned above.
It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE FIGURES

The invention will be better understood on reading the following detailed description of an exemplary non-limiting embodiment thereof, as well on examining the figures, schematic and partial, of the accompanying drawing, on which :

figure 1 shows an example of a locking device according to the invention,
figures 2a to 2f illustrate different steps of the method according to the invention for locking a moving element, and
figures 3a to 3d illustrate different steps of the method according to the invention for releasing a moving element.

DETAILED DESCRIPTION OF ONE WAY OF CARRYING OUT THE INVENTION

Reference will now be made in detail to the preferred embodiment of the present invention which is illustrated in the accompanying drawing. Wherever possible, the same reference numbers will be used throughout the figures to refer to the same or like parts.
Figure 1 shows an example of a locking device 1 according to the invention, intended to lock (or stop) and/or release a moving element 2, particularly a drum of a washing machine or a moving member which rotates integrally with the drum.
The locking device 1 comprises a locking arm 3 slidable between an outward position O, which can be seen for example on figure 2e, and a retracted position R, which can be seen for example on figure 2a.
The locking arm 3 is adapted to be fitted into one aperture 4 formed on the peripheral circumference of the moving element 2 to stop the moving element 2 at a given position, especially a loading/unloading position of a washing machine.
The locking arm 3 comprises a middle tip 3a and two side tips 3b intended to be fitted into the aperture 4 of the moving element 2. In particular, the two side tips 3b are arranged to come into contact with the first 4a and second 4b borders of the aperture 4. The tips, and particularly the two side tips 3b, are therefore advantageously flexible.
The locking device 1 further comprises detection means constituted by a first sensor 6 and a second sensor 7. The first sensor 6 and the second sensor 7 are arranged to overlap the moving element 2 when the locking device 1 is placed close to the moving element 2.
The distance D between the first sensor 6 and the second sensor 7 is chosen so as to be less than the width L, particularly the circumferential width L, of the aperture 4. Similarly, the width W of the locking arm 3 is chosen so as to be less than the width L of the aperture 4. Preferably, the width W of the locking arm 3 is much lower than the width L of the aperture 4. Thus, there is no friction when the locking arm 3 is inserted and/or removed from the aperture 4.
The locking device 1 further comprises operating means 5, having for example a torque motor for moving the locking arm 3 and electronics for reading the state of the first 6 and second 7 sensor.
Figures 2a to 2f illustrate different steps of the method according to the invention for locking (or stopping) the moving element 2.
In this example, the moving element is a pulley 2 of a washing machine, particularly a laundry washing machine. The locking device 1 is placed on a fixed supporting structure of the washing machine close to the pulley 2 so that the first 6 and second 7 sensors overlap the pulley 2. The pulley 2 has an open window 4 formed on its peripheral circumference.
Once a wash cycle is ended and the drum of the washing machine needs to be locked for unloading items, the steps for automatically locking the pulley 2 are as follows.
As shown on figure 2a and 2b, the pulley 2 rotates at slow speed in the clockwise direction F1 and the first 6 and second 7 sensors do not face the open window 4.
Then, the first sensor 6 faces the open window 4, as shown on figure 2c, and the rotation of the pulley 2 continues until both the first sensor 6 and the second sensor 7 face the open window 4, as shown on figure 2d.
Once the first 6 and second 7 sensors are in a relative positioning with respect to the open window 4 in which the two sensors 6 and 7 face the open window 4 and the locking arm 3 is at equal distance from the first border 4a and the second border 4b of the open window 4, the locking arm 3 quickly moves forward from the retracted position R to the outward position O to lock the pulley 2, as shown on figure 2e.
The fast movement of the locking arm 3 towards the open window 4 enables locking the pulley 2 with no effort and easily.
Once the pulley 2 is locked thanks to the locking arm 3 in the outward position O, motor power is cut down, if not already done, and gravity gives the final position to the pulley 2, as shown on figure 2f, the locking arm 3 being thus in contact with the second border 4b of the open window 4. Indeed, due to gravity, the pulley 2 rotates in the counterclockwise directions F2.
Figures 3a to 3d illustrate different steps of the method according to the invention for releasing the pulley 2.
Before starting a new wash cycle, the washing machine is loaded with items to be washed. Then, a user may start a wash cycle and an unlocking sequence of the pulley 2 may begin.
Before rotating the pulley 2, the detection means of the locking device 1 detect, thanks to the first 6 and second 7 sensors, whether the locking arm 3 is in contact with the first border 4a or the second border 4b of the open window 4.
If there is a contact between the locking arm 3 and the first border 4a of the open window 4, the pulley 2 is rotated in the counterclockwise direction F2. However, if there is a contact between the locking arm 3 and the second border 4b of the open window 4, the pulley 2 is rotated in the clockwise direction F1.
In the illustrated example, the locking arm 3 is in contact with the second border 4b of the open window 4, as shown on figure 3a.
Therefore, the pulley 2 begins to rotate at slow speed in the clockwise direction F1, as shown on figure 3b.
The rotation continues until a position is reached in which the locking arm 3 is centered relative to the open window 4, as shown on figure 3c.
The direction of rotation is determined by the detection means which then act on the operating means 5, and particularly on electronics of the operating means 5, to indicate the correct sense of direction.
When the first 6 and second 7 sensors detect a relative positioning with respect to the open window 4, as shown on figure 3c, in which there is no contact between the locking arm 3 and the first 4a and second 4b borders of the open window 4 and in which the locking arm 3 is at equal distance from the first 4a and second 4b borders, the locking arm 3 moves back from the outward position O to the retracted position R so as to release the pulley 2.
Finally, as motor power is cut down, the load of the items placed inside the drum of the washing machine gives another stable position to the pulley 2, and thus to the drum.
The pulley 2 may for example rotate a little bit in the counterclockwise direction F2, as shown on figure 3d, before stopping. Then, a new wash cycle may begin.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention.
Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims.
Throughout the present disclosure, the term "comprising a" is intended to be synonymous with "comprising at least one", unless specified otherwise.

Claims

A locking device (1) comprising:
- a moving element (2) comprising an aperture (4) formed on the moving element (2) between a first border (4a) and a second border (4b) with a width (L),

- a locking arm (3) slidable between an outward position (0) and a retracted position (R), said locking arm (3) being adapted to be fitted into said aperture (4) to stop the moving element (2) at a given position,

- operating means (5) for the locking arm (3) which are able to move the locking arm (3) from said retracted position (R) to said outward position (0) for locking the moving element (2) and vice versa for releasing the moving element (2),

- detection means (6, 7) acting on said operating means (5) to allow movement of said locking arm (3), wherein said detection means (6, 7) are adapted to detect at least one relative positioning of said detection means (6, 7) with respect to said aperture (4) formed on the moving element (2) and to act on said operating means (5) to allow positioning said locking arm (3) in said outward position (0) or said retracted position (R), whereby the width (W) of the locking arm (3) is less than the width (L), in particular the circumferential width, of said aperture (4), and

- that said detection means (6, 7) comprise a first sensor (6) and a second sensor (7) both intended to face said aperture (4) of the moving element (2),
characterized by the fact that the distance (D) between the first sensor (6) and the second sensor (7), is less than the width (L), in particular the circumferential width, of said aperture (4).
The locking device (1) according to claim 1, characterized by the fact that said at least one relative positioning of the detection means (6, 7) with respect to the aperture (4) corresponds to a position in which at least one of the first (6) and second (7) sensors face the aperture (4) and/or a position in which both the first (6) and second (7) sensors face the aperture (4).
The locking device (1) according to any one of claims 1 or 2, characterized by the fact that said at least one relative positioning of the detection means (6, 7) with respect to the aperture (4) is a position in which both the first (6) and second (7) sensors face the aperture (4) and the detection means (6, 7) are arranged to act on the operating means (5) to allow positioning the locking arm (3) in the outward position (0) or the retracted position (R) while the detection means (6, 7) and the aperture (4) are in said relative positioning.
The locking device (1) according to any preceding claim, characterized by the fact that said locking arm (3) comprises separate tips (3a, 3b), particularly three separate tips, intended to be fitted into said aperture (4) formed on the moving element (2).
The locking device (1) according to claim 4, characterized by the fact that said tips (3a, 3b) are flexible.
The locking device (1) according to any preceding claim, characterized by the fact that said detection means (6, 7) are configured to detect at least one relative positioning of the detection means (6, 7) with respect to said aperture (4) enabling positioning said locking arm (3) in said outward position (0) or said retracted position (R) with no contact between said locking arm (3) and said aperture (4).
A washing machine comprising
- a processing tub,

- a drum mounted rotatably in the processing tub,

- possibly, at least one moving member (2) which rotates integrally with the drum, whereby said washing machine further comprises a locking device (1) according to any preceding claim and said drum or said at least one moving member (2) comprises the aperture (4) into which the locking arm (3) of the locking device (1) is adapted to be fitted to stop said drum or said at least one moving member (2) at a given position.
The washing machine according to claim 7, characterized by the fact that said drum is connected to a first shaft, by the fact that said at least one moving member is a pulley (2) which is fixed at one end of the first shaft of said drum and connected by means of a transmission belt to a second shaft of an electric motor for moving the drum, and by the fact that said pulley (2) comprises said aperture (4).
The washing machine according to claim 7 or 8, characterized by the fact that said aperture (4) is an open window or a hole formed on the peripheral circumference of said at least one moving member (2).
A method for locking or releasing a moving element (2) comprising an aperture (4), characterized by the fact that the method is implemented by means of a locking device (1) according to any one of claims 1 to 6 and by the fact that it comprises the step of moving the locking arm (3) from the retracted position (R) to the outward position (O) or vice versa when the detection means (6, 7) detect the at least one relative positioning of the detection means (6, 7) with respect to the aperture (4) formed on the moving element (2).
The method according to claim 10 wherein the at least one relative positioning of the detection means (6, 7) with respect to the aperture (4) is a position in which both the first and second sensors (6, 7) face the aperture (4).
The method according to claim 10 or 11, characterized by the fact that it comprises the step of moving the locking arm (3) from the retracted position (R) to the outward position (0) or vice versa when the first sensor (6) and the second sensor (7), face the aperture (4) and are located at equal distance from the first (4a) and second (4b) borders of the aperture (4).
The method according to any one of claims 10 to 12, characterized by the fact that the steps for locking the moving element (2) are successively as follows :
- letting the moving element (2) (2) rotate until a relative positioning of the detection means (6, 7) with respect to the aperture (4) is reached in which the detection means, in particular both the first sensor (6) and the second sensor (7), face the aperture (4),

- moving the locking arm (3) from the retracted position (R) to the outward position (O) to lock the moving element (2).
The method according to any one of claims 10 to 13, characterized by the fact that the steps for releasing the moving element (2) are successively as follows rotating the moving element (2) until a relative positioning of the detection means (6, 7) with respect to the aperture (4) is reached in which the locking arm (3) has no contact with the first (4a) and second (4b) borders of the aperture (4), moving the locking arm (3) from the outward position (O) to the retracted position (R) to release the moving element (2).
The method according to claim 14, characterized by the fact that the step of rotating the moving element (2) is preceded by a step in which the detection means (6, 7), in particular the first sensor (6) and/or the second sensor (7), detect whether the locking arm (3) is in contact with the first border (4a) or the second border (4b) of the aperture (4) in order to determine the direction of rotation of the moving element (2).