EP3222768B1

EP3222768B1 - Laundry machine

Info

Publication number: EP3222768B1
Application number: EP16161614.9A
Authority: EP
Inventors: Alberto Santarossa
Original assignee: Electrolux Appliances AB
Current assignee: Electrolux Appliances AB
Priority date: 2016-03-22
Filing date: 2016-03-22
Publication date: 2019-03-20
Anticipated expiration: 2036-03-22
Also published as: EP3222768A1

Description

Field of the invention

The present invention relates to laundry treatment appliances or machines. In more detail, the present invention refers to appliances for washing laundry and/or washing and drying laundry comprising a rotating drum, both for domestic and professional use. Particularly, the present invention relates to a laundry machine comprising a load sensing device for evaluating a weight of laundry introduced into the laundry machine and a method to assembly said laundry machine.

Background of the invention

Washing and washing/drying laundry machines - which will be referred to simply as laundry machine in the following - typically comprise a casing substantially parallepiped-shaped.
The casing accommodates a laundry-treating chamber, comprising a drum, generally rotatable, apt to contain the laundry to be washed (and dried in the case of washing/drying laundry machines).
The laundry-treating chamber further comprises a tub in which the drum is rotatably contained.
The tub is suspended inside the casing by means of suspension elements (such as extension springs) and damping elements. Typically, suspension elements connect the tub to a top portion of the casing, while damping elements connect the tub to a lower portion of the casing.
A front panel of the casing may be provided with a loading opening to access the treating chamber for loading/unloading the laundry, and a door is provided for closing the loading opening, particularly during the laundry machine operation; in such case the laundry machine is defined as front-loading laundry machine. Alternatively, a top panel of the casing may be provided with a loading opening to access the treating chamber for loading/unloading the laundry, and a door is provided for closing the loading opening, particularly during the laundry machine operation; in such case the laundry machine is defined as top-loading laundry machine.
The casing also accommodates the electrical, electronic, mechanical (e.g., a motor for rotating the drum and an electronic control system for managing the laundry machine operation etc.), and hydraulic components necessary for the operation of the laundry machine (e.g., inlet and outlet hydraulic systems, treating agent dispenser etc.).
Generally, the laundry machine further comprises a control interface, e.g. comprising one or more among buttons, pushbuttons, knobs and displays for allowing a user set/select or to be informed about operating parameters and laundry-treating processes.
Finally, the laundry machine may comprise a treating agent drawer adapted to accommodate treating agents, e.g. powdered/liquid detergent and/or softener, to be inputted in the hydraulic system of the laundry machine for treating laundry.
In order to achieve laundry treating processes having an improved efficiency it is known to adjust a duration, a spinning angular velocity and/or drying temperatures of the laundry treating processes based on a weight of the laundry to be treated and/or being treated.
Therefore, in the art many expedients have been proposed in order to automatically evaluate a weight of the laundry to be treated.
For example, GB2225030 discloses a load indicator for a domestic washing machine having a switch panel and a tub for detergent solution, which tub is suspended resiliently relatively to a mounting frame, comprising means responsive to vertical movement of said tub relatively to the mounting frame for providing a corresponding indication of the loaded state of the tub in an indicator window of the switch panel. Particularly, an electric coil connected to the frame of the domestic washing machine surrounds a spring and a magnetic core that are attached to the tub of the domestic washing machine. A movement of the tub and of the magnetic core is detected as a change in a magnetic flux by the electric coil and is connected to a weight increase that is electronically displayed.
Document WO 2009/083760 A1 discloses an alternative load detecting device as well as an alternative placement of the device; the load detecting device comprises a magnet and a magnetic sensor, each associated to one of two slidable elements composing a damper suitable to keep the oscillating tub suspended.

Summary of invention

The Applicant has realized that the art do not provide a satisfactory load sensing device allowing for an accurate evaluation of a weight of laundry provided in the laundry machine and, at the same time, an easy and cost-effective implementation within the laundry machine.
For example, the Applicant has found that the known solutions couple load sensing devices, or portions thereof, with moving parts such as the tub and with fixed parts such as the machine cabinet; such a coupling may require connecting elements requiring a quite complex mounting means because a portion on the load sensing device has to be connected to fixed part, whereas a further portion has to be connected to moving parts; moreover, the displacement of the moving parts is sometime unpredictable (due for example to the drum speed as well as the unbalance state of the laundry contained therein), different from the theoretical linear movement between said parts, resulting in a unprecise acquisition of the displacement values, with a consequent mistake of weight estimation.
The Applicant has tackled the problem of devising an improved solution able to overcome, at least partly, the drawbacks of the prior art.
In particular, the Applicant has found that coupling the load sensing device, having a first device section and a second device section, with the suspension element so that the first device section is associated of a first portion of the suspension element and with the second device section associated to a second portion of the suspension element or vice versa, so that the change in length of the suspension element causes the change of distance between the first and the second sensor elements, allow a reliable connection of all load sensing device components, being the latter connected to the same part (suspension element), and at the same time it improves the reliability of the signal acquired, because the load sensing device follows the movement / misalignments of the suspension element.
One or more aspects of the solution according to embodiments of the invention are set out in the independent claims, with advantageous features of the same solution that are indicated in the dependent claims.
An aspect of the solution according to one or more embodiments of the present invention relates to a laundry machine for treating laundry items. The laundry machine comprises a cabinet for accommodating components necessary for the operation of the laundry machine, a washing tub comprising a rotatable drum for containing laundry items, the washing tub being enclosed by the cabinet such that it can be moved in a floating manner inside said cabinet, at least one suspension element comprising a first portion associated to the cabinet and a second portion associated to the washing tub for movably coupling the tub with the cabinet of the laundry machine, and a load sensing device for measuring a physical value related to the weight of laundry items provided in the washing tub, wherein the load sensing device comprises a device first member comprising a first sensor element and a device second member comprising a second sensor element. The load sensing device is coupled with the at least one suspension element with the device first member associated to the first portion of said suspension element and with the device second member associated to the second portion of the suspension element or vice-versa. Thereby, the change of length of the suspension element causes the change of distance between said first and the second sensor elements.
In an advantageous embodiment of the invention, the first sensor element comprises at least one permanent magnet.
In an advantageous embodiment of the invention, the second sensor element comprises at least one magnetic field sensor.
In an advantageous embodiment of the invention, the at least one magnetic field sensor comprises a Hall effect sensor.
In an advantageous embodiment of the invention, the second sensor element comprises a sensor arrangement provided with an electronic board.
In an advantageous embodiment of the invention, the laundry machine further comprises a control system configured for controlling the operation of the laundry machine. Preferably, the electronic board further mounts electronic components for exchanging signals with the control system of the laundry machine.
In an advantageous embodiment of the invention, the device first member and the device second member are slidably coupled one another.
In an advantageous embodiment of the invention, the device first member comprises a tubular body which delimits a cavity. Preferably, the cavity is adapted to receive at least a portion of the second device section.
In an advantageous embodiment of the invention, the device second member further comprises a sliding portion. Preferably, the sliding portion is shaped to slidably fit the cavity delimited by the tubular body of the device first member.
In an advantageous embodiment of the invention, the first sensor element is provided in the tubular body of the device first member and, preferably, the second sensor element is provided in the sliding portion of the device second member. Alternatively, the first sensor element is provided in the sliding portion of the device second member and, preferably, the second sensor element is provided in the tubular body of the device first member.
According to the invention, the suspension element comprises an upper coupling end for coupling with the cabinet of the laundry machine, a sequence of stacked spring coils, and a lower coupling end for coupling with the washing tub. Further, the device first member comprises at least one coupling protrusion protruding from the device first member, the at least one coupling protrusion is adapted to engage with the suspension element.
In an advantageous embodiment of the invention, the at least one coupling protrusion comprises a hooked free end adapted to engage with an upper spring coil of the sequence of stacked spring coils of the suspension element.
In an advantageous embodiment of the invention, the device first member is adapted to fit a space defined by the sequence of stacked spring coils of the spring element.
In an advantageous embodiment of the invention, the suspension element comprises an upper coupling end for coupling with the cabinet of the laundry machine, a sequence of stacked spring coils, and a lower coupling end for coupling with the washing tub. Preferably, the second member comprises at least one coupling protrusion protruding from the device second member, the at least one coupling protrusion is adapted to engage with the suspension element.
In an advantageous embodiment of the invention, the at least one coupling protrusion comprises a hooked free end adapted to engage with a bottom spring coil of the sequence of stacked spring coils of the suspension element.
In an advantageous embodiment of the invention, the washing tub comprises at least one retaining element. Preferably, the device second member comprises a clamping portion arranged for connecting to the at least one retaining element of the washing tub.
In an advantageous embodiment of the invention, the at least one retaining element of the washing tub comprises an eyelet and the at least one suspension element comprises a lower coupling end having a hook arranged for fitting the eyelet of the at least one retaining element. Preferably, the clamping portion of the device second member is adapted to be fitted into the same eyelet of the at least one retaining element in which the hook of the lower coupling end of the at least one suspension element is fitted into. Alternatively, the washing tub comprises two retaining elements, one associated to the lower coupling end of the suspension element and one associated to the device second member; preferably, one retaining element comprises an eyelet and the at least one suspension element comprises a lower coupling end having a hook arranged for fitting the eyelet of the at least one retaining element; moreover, the other retaining element preferably comprises an eyelet and the clamping portion of the device second member is adapted to be fitted into said eyelet.
In an advantageous embodiment of the invention, the clamping portion of the device second member is adapted to be coupled with the lower coupling end of the at least one suspension element.
In an advantageous embodiment of the invention, the clamping portion of the device second member is provided astride the lower coupling end of the at least one suspension element.
In an advantageous embodiment of the invention, the device first member is associated to the first portion or to the second portion of the suspension element through connection means allowing the rotation of said first portion around the fulcrum defined by the connection point between said connection means and said suspension element
Another aspect of the present invention proposes a method of assembly a laundry machine. The method comprises providing a cabinet for accommodating components necessary for the operation of the laundry machine, providing a washing tub comprising a rotatable drum for containing laundry items, providing at least one suspension element comprising a first portion and a second portion, associating the first portion of said suspension element to the cabinet, associating the second portion of said suspension element to the washing tub, thereby movably coupling the tub with the cabinet of the laundry machine such that it can be moved in a floating manner inside said cabinet, and providing a load sensing device for measuring a physical value related to the weight of laundry items provided in the washing tub, wherein the load sensing device comprises a device first member comprising a first sensor element and a device second member comprising a second sensor element. Providing a load sensing device comprises coupling the device first member with the first portion of said suspension element, and coupling the device second member with the second portion of said suspension element. Alternatively, providing a load sensing device comprises coupling the device second member with the first portion of said suspension element, and coupling the device first member with the second portion of said suspension element.
In an advantageous embodiment of the invention, the at least one suspension element further comprises a sequence of stacked spring coils interposed between said first portion and second portion of said suspension element, the sequence of stacked spring coils delimiting an inner space, and the device first member of the load sensing device further comprises at least one coupling protrusions. Preferably, coupling the device first member with the first portion of said suspension element comprises inserting the device first member into the inner space defined by the sequence of stacked spring coils until said coupling protrusion engages an upper spring coil of the sequence of stacked spring coils.
In an advantageous embodiment of the invention, the device second member further comprises a respective coupling protrusion, and the device first member of the load sensing device further comprises a cavity. Preferably, coupling the device second member with the second portion of said suspension element comprises inserting the device second member into the cavity of the device first member until the respective coupling protrusions engages a lower spring coil of the sequence of stacked spring coils.
In an advantageous embodiment of the invention, the device second member further comprises a respective clamping portion, and the device first member of the load sensing device further comprises a cavity. Preferably, coupling the device second member with to the second portion of said suspension element comprises inserting the device second member into the cavity of the device first member, and coupling the respective coupling protrusions with the second portion of said suspension element.

Brief description of the annexed drawings

These and other features and advantages of the present invention will be made apparent by the following description of some exemplary and non limitative embodiments thereof. For its better intelligibility, the following description should be read making reference to the attached drawings, wherein:

Figure 1A is a schematic perspective view of a laundry machine in which a load sensor according to an embodiment of the invention may be implemented;
Figure 1B is a schematic perspective front view of the laundry machine of Figure 1A with removed parts;
Figure 1C is a schematic perspective rear view of the laundry machine of Figure 1A with removed parts;
Figure 2A is a schematic exploded view of a load sensor according to a first embodiment of the invention coupleable with a suspension element of the laundry machine,
Figures 2B to 2E are side views and cross-sectional side views of the load sensor according to the first embodiment of the invention coupled with the suspension element of the laundry machine,
Figure 2F is a schematic close up of the suspension element coupled with the load sensor according to the first embodiment of the present invention in its working position inside the laundry machine,
Figure 3A is a schematic exploded view of a load sensor according to a second embodiment of the invention coupleable with a suspension element of the laundry machine,
Figures 3B to 3E are side views and cross-sectional side views of the load sensor according to the second embodiment of the invention coupled with the suspension element of the laundry machine, and
Figure 3F is a schematic close up of the suspension element coupled with the load sensor according to the second embodiment of the present invention in its working position inside the laundry machine.

Detailed description of preferred embodiments of the invention

Referring now to the drawings, Figures 1A to 1C are schematic are perspective views of a laundry machine 100 in which a load sensor (not detailed in Figures 1A to 1C ) according to an embodiment of the invention may be implemented.
The laundry machine 100 is a machine for treating laundry, such as for example a laundry washing machine or a laundry washing/drying machine, of the front-loading type. Anyway, it should be apparent from the following description that laundry machines of the top-loading type may also benefit from the solution according to the present invention.
In the example at issue, the laundry machine 100 comprises a casing or cabinet 105 preferably substantially parallelepiped-shaped, which encloses a washing tub, or simply tub 107 (as shown in the perspective views with removed parts of Figures 1B and 1C ), preferably substantially cylindrically-shaped, wherein the laundry is treated, along with any other component of the laundry machine 100 necessary for its operation (e.g., hydraulic, electronic and electromechanical apparatuses as described in the following).
The tub 107 houses a rotatable drum 110 preferably substantially cylindrically shaped, which, in operation, rotates about an axis A in order to tumble the laundry to be washed.
Typically, the tub 107 is suspended in the casing 105 in such a way to be substantially free to oscillate/float during its operation. For example, the tub 107 is connected to the casing 105 in movable manner by means of suspension elements 111 (e.g., spring elements, for example extension springs) and damping elements 112 (e.g., shock absorbers).
Preferably, each suspension element is coupled with the casing 105 and with the tub 107 by means of respective casing retaining element 113c and tub retaining element 113t.
In an embodiment of the present invention, as shown in the example of Figures 1B and 1C , the casing retaining element 113c for the suspension element 111 is formed at least partly on a bracket element 105b of the casing 105. The bracket element 105b being arranged in order to mechanically couple two opposite side element 105c of the casing 105 (omitted in the Figures 1B and 1C , but a portion of such side element 105c is visible in the following Figures 2F and 3F ).
In addition, the tub 107 comprises, in a backside or backwall 107a thereof, a shaft opening(not visible in the figures), in which a drum rotor shaft 110a is inserted. The rotor shaft 110a is attached to the drum 110 and rotatably connected by means of a transmission apparatus 115 to a, preferably electric, drum motor 120 comprised in the laundry machine 100 in order to rotate the drum 110 during operation. The drum motor 120 is preferably, although not limitatively, positioned in a bottom position with respect to the casing 105. The transmission apparatus 115 may comprise a transmission belt or chain 115a coupled with a pair of pulleys 115b and 115c, of which a first pulley 115b is mounted to the drum rotor shaft 110a while a second pulley 115c is mounted to a motor shaft 120a.
Alternatively, in other embodiments according to the present invention (not shown in the Figures), the rotating movement may be transferred to the drum in any other known manner; for example, a motor may be directly connected to the drum (so called "direct drive"), with the motor shaft coinciding to the drum shaft.
In order to allow a user to access the tub 107 and the inside of the drum 110 (for loading/unloading the laundry), a loading/unloading opening is advantageously provided on a front side of the laundry machine 100. The loading/unloading opening is closable by a door 125 (shown in closed configuration in Figure 1A ), which is hinged, preferably, to the casing 105 by means of a hinge (not shown in the figures).
The tub 107 is provided with a tub opening 107c, and the drum 110 is provided with a drum opening having substantially the same size and alignment of the tub opening 107c. The tub opening 107c is adapted to be aligned with the loading/unloading opening provided in the casing 105, and with the drum opening of the drum 110.
Preferably, in order to achieve a watertight connection between the loading/unloading opening and the tub opening 107c (in order to avoid leakages of washing liquid into the casing 105), a bellows 130, preferably made of an elastomeric and waterproof material, is mounted in a watertight manner (such as by gluing, by welding, by interference fitting, etc.) to a border of the loading/unloading opening and is coupled with a border of the tub opening 107c.
The tub 107 is fluidly connected to a hydraulic apparatus (not shown in the drawings) adapted to provide washing liquids (e.g., water mixed with detergents) in the washing tub 107 for treating the laundry therein, and to exhaust such liquids once used.
The laundry machine 100 may possibly comprise also a drying air apparatus (not shown) fluidly connected with the tub 107 adapted to heat up and blow drying air into the tub and draw therefrom moisturized cool air.
In addition, a user interface 140 is advantageously provided, preferably, although not limitatively, on a top portion 105t of the casing 105. Preferably, the user interface 140 may comprise a control panel 140a for selecting laundry treatment cycles (e.g., a set of operations and parameters designed for treating peculiar fabrics, such as wool items) and / or parameters (e.g. water/washing liquid temperature) to be carried out by the laundry machine 100, or to display information, and a drawer 140b for loading laundry-treating products (e.g., detergents, softeners, bleachers, etc.).
The laundry machine 100 is advantageously provided with a control system 150 (e.g., schematically indicated by a dashed rectangle in Figure 1A , and comprising one or more microprocessors/microcontrollers and/or other electronic devices) adapted to control the laundry machine 100 operation, which is preferably, although not necessarily, placed in a top position inside the casing in order to be less prone to contacts with liquids or humidity possibly leaking from the tub 107.
According to an embodiment of the present invention, the laundry machine 100 further comprises one or more load sensing devices arranged for providing a (electric) signal indicative of a weight of items (i.e., laundry items) provided in the drum 110 enclosed by the tub 107.
Preferably, the load sensing device may be arranged for assessing a portion of a total weight due to water/washing liquid introduced in the tub 107 in order to perform a laundry-treating procedure and estimating a net weight of the laundry loaded in the rotating drum.
Preferably, the load sensing device is based on measurements of a relative displacement between two members of the load sensing device.
Indeed, the load sensing device is designed in such a way that the relative displacement mentioned above is associated with a corresponding displacement between the tub 107, which as mentioned above may freely oscillate/float, and the casing 105, which substantially stand statically during the laundry machine 100 operation.
In its turn, the extent of displacement between the tub 107 and the casing 105 is indicative of the weight of the laundry loaded in the rotating drum 110 of the laundry machine 100.
Particularly, the displacement between the tub 107 and the casing 105 comprises two main components: a time-varying component generated by oscillations induced, e.g. by the rotation of the rotating drum 110 during operation or by the action of loading laundry in the rotating drum 110, and a substantial time-continuous component generated by the weight of the laundry (and possibly water/washing liquid) loaded in the rotating drum 107.
In one embodiment of the invention, the measurement of the displacement between the two members of the load sensing device is based on of variations in a magnetic field (as described in the following).
In an alternative embodiment of the invention, the measurement of the displacement between two members of the load sensing device is based on different physical expedients, such as for example optical measurements.
As shown Figures 2A to 2F , the load sensing device 200 according to a first embodiment of the invention is preferably adapted to be installed at a suspension element 111 of the laundry machine 100.
Starting from top and then proceeding downward with respect to the Figures 2A to 2F , the generic suspension element 111 is preferably formed by an upper coupling end 111a, a sequence of stacked spring coils 111b, and a lower coupling end 111c.
The upper coupling end 111a has a shape adapted to be connected to a casing retaining element 113c provided in the (upper side of) the casing 105.
For example, the upper coupling end 111a is shaped in the form of a hook adapted to engage a corresponding hole 202 (best view in Figure 2F ) comprised in the casing retaining element 113c provided on a side element 105c of the casing 105 (with which the bracket element 105b mentioned above couples).
Similarly, the lower coupling end 111c has a shape adapted to connect to a tub retaining element 113t provided the tub 107.
For example, the lower coupling end 111c is shaped in the form of a beam ending with a hook adapted to engage an eyelet 205 of the tub retaining element 113t protruding from the washing tub 107 of the laundry machine 100.
The suspension element 111 is preferably made of an elastic and resistant material such as steel.
According to an embodiment of the invention, the load sensing device 200 comprises two main members designed to slide one inside the other.
A device first (upper) member 210 is fixed to an upper spring coil 220a of the sequence of stacked spring coils 111b of the spring element 111. The upper spring coil 220a joins the upper coupling end 111a to the sequence of stacked spring coils 111b.
For example, the device first member 210 comprises a, preferably cylindrical, tubular body 210a adapted to fit a (cylindrical) inner space defined by the sequence of stacked spring coils 111b of the spring element 111.
In order to be fixed to the upper spring coil 220a, the device first member 210 comprises one or more, two in the example of Figures 2A to 2F , coupling protrusions 225. Preferably, each coupling protrusion 225 protrudes from a top end 210b of the device first member 210 and comprises a hooked free end 225a adapted to engage with upper spring coil 220a (e.g., the hooked free end 225a snap-fits the upper spring coil 220a).
Preferably, the device first member 210 further comprises one or more, two in the example of Figures 2A to 2F , guiding protrusions 227. The guiding protrusions 227 protrude from the top end 210a of the device first member 210 and have a rod-like shape. The guiding protrusion 227 are arranged for guiding the movement of the device first member 210 in the space defined by the sequence of stacked spring coils 111b of the spring element 111 and to maintain a correct positioning of the device first member 210 while the sequence of stacked spring coils 111b is deformed by forces acting on the suspension element 111 (i.e., associated with displacements of the tub 107).
The tubular body 210a of the device first member 210 preferably delimits a cavity 230.
The cavity 230 is preferably adapted to receive, at least partly, a second (lower) device member 235 of the load sensing device 200 (described in the following). In other words, at least a portion of the device second member 235 is preferably adapted to fit the cavity 230 of the device first member 210 and to slide inside it.
To this purpose, the cavity 230 is accessible through a hole 237 provided in a bottom end 210c of the tubular body 210a of the device first member 210 (i.e., the bottom end 210c is opposite to the top end 210b).
In one embodiment of the invention, the device first member 210 preferably comprises at least one first sensor element. For example the device first member 210 comprises two, preferably permanent, magnets 215.
For example, each permanent magnet 215 is provided in a respective housing or niche 240 provided in the tubular body 210a of the device first member 210.
Preferably, the niche 240 is provided in such a way that the permanent magnet 215, once inserted in the niche 240, faces the cavity 230 of the device first member 210. Even more preferably, the permanent magnet 215 has an elongated shape with the longest size aligned with a sliding direction of the device second member 235 within the cavity 237 of the device first member 210. This configuration ensure that the device second member 235 results immersed in a magnetic field for a prevalent extent of its sliding inside the device first member 210.
Furthermore, in case of a device first member 210 comprising two permanent magnets 215 (such as in the exemplary embodiment depicted in Figures 2A to 2F ), preferably, the two permanent magnets 215 are arranged axially aligned (i.e., on in front of the other, as best visible in Figures 2A and 2E ). Even more preferably, the permanent magnets 215 are provided in the respective niches 240 in such a way to have facing opposite magnetic north/south poles, thus generating a substantially uniform magnetic field within the cavity 237 through which the device second member 235 slides.
The second (lower) device member 235 preferably comprises a sliding portion 235a and a second sensor element, such as a sensor arrangement 235b.
The sliding portion 235a is shaped in such a way to fit the cavity 230 of the tubular body 210a of the device first member 210.
Particularly, the sliding portion 235a is shaped in such a way to slidably couple with the tubular body 210a of the device first member 210.
Advantageously, the sliding portion 235a and the tubular body 210a are designed in such a way that the sliding portion 235a is not able to leave the cavity 230 of the tubular body 210a even at a maximum elongation of the sequence of stacked spring coils 111b of the suspension element 111. For example, the sliding portion 235a is formed with a cylindrical shape and size substantially corresponding to the cylindrical shape and size of the cavity 230 and of the hole 237 of the tubular body of the device first member 210.
In a non-limiting embodiment of the invention, the sliding portion 235a may be shaped in such a way to maintain a predetermined orientation while sliding in the cavity 237 of the tubular body 210a of the device first member 210.
For example, the sliding portion comprise a slot 245 suited for receiving a sliding guide. In an embodiment of the invention each one of the niches 240 provided in the tubular body 210a for housing respective magnets 215 is advantageously used as sliding guide.
Preferably, each niche 240 may be formed in such a way to protrude inwards in the cavity 237 of the tubular body 210a of the device first member 210 in order to act also as a sliding guide for a respective slot 245 of the sliding portion 235a. Thus, during the sliding of the sliding portion 235a in the cavity 237, the niches 240 received in the slots 245 guide the sliding of the sliding portion 235a along the cavity 237, and advantageously prevent any rolling of the sliding portion 235a.
It should be noted that in alternative embodiments (not shown), dedicated sliding guides may be provided instead and the niches for the permanent magnets may be made flush with an inner wall of the tubular body 210a which delimits the cavity 237.
Further alternative embodiments of the present invention may comprise a load sensing device without slots and sliding guides.
The device second member 235 is preferably fixed to a lower spring coil 220b of the sequence of stacked spring coils 111b of the spring element 111. The lower spring coil 220b joins the lower coupling end 111c to the sequence of stacked spring coils 111b
In order to be fixed to the lower spring coil 220a, the device second member 235 preferably comprises one or more coupling protrusions, such as a hooked protrusion 247, shown in the example of Figures 2A to 2F .
Preferably, a hooked protrusion 247 protrudes from a lower portion of the sliding portion 235a of the device second member 235 and comprises a hooked shape adapted to engage with the lower spring coil 220b (e.g., the hooked protrusion 247 snap-fits the lower spring coil 220b).The sliding portion 235a of the device second member 235 preferably houses the sensor arrangement 235b.
In one embodiment of the invention, the sliding portion 235a comprises a housing cavity 246 in which the sensor arrangement 235b may be fitted.
Preferably, the sensor arrangement 235b comprises an electronic board 250 mounting at least a sensor component designed to measure a relative displacement between the two members 210 and 235 of the load sensing device 200 by interacting with the first sensor element, i.e. the permanent magnets 215, of the device first member 210. In one embodiment of the invention, the sensor arrangement 235b comprises at least one magnetic field sensor 255. For example, the magnetic field sensor 255 comprises a Hall effect sensor.
Preferably, the electronic board 250 further mounts electronic components (e.g., resistors, capacitances, transducer elements and wirings) for exchanging signals (preferably electric, even though electromagnetic and/or optical signals are not excluded) with the control system 150 of the laundry machine 100.
For example, the sensor arrangement 235b comprises a connector terminal 256 (as best view in Figure 2E ) which is accessible through a lower aperture 246a of the housing cavity 246 in order to be connectable to the control system 150 of the laundry machine 150.
Even more preferably, the sensor arrangement 235b further comprises an electronic managing element 257, such as for example a microprocessor, a microcontroller or a similar electronic component.
Advantageously, the electronic managing element 257 is configured for pre-processing electric signals provided by the magnetic field sensor 255 before forwarding them to the control system 150. For example, the electronic managing element 257 is configured for filtering, amplifying and digitalizing the electric signals provided by the magnetic field sensor 255.
Furthermore, the electronic managing element 257 may be configured for attenuating portions of the electric signal provided by the magnetic field sensor 255 due to time-varying components of the displacement between the tub 107 and the casing 105 and/or removing offsets of the electric signal provided by the magnetic field sensor 255 due to the weight of any water/washing liquid in the tub 107.
It should be noted that the device first member 210 is fixed to the upper spring coil 220a of the sequence of stacked spring coils 111b - which is substantially integral with the upper coupling end 111a of the spring element 111 and thus with the casing 105 of the laundry machine 100 to which the upper coupling end 111a is coupled.
Therefore position of the device first member 210, and particularly of the first magnetic sensor element (i.e., the permanent magnets 215), is substantially integral with the casing 105 of the laundry machine 100.
Similarly, the device second member 210 is fixed to the lower spring coil 220b of the sequence of stacked spring coils 111b - which is substantially integral with lower coupling end 111c of the spring element 111 and thus with the tub 107 of the laundry machine 100 to which the lower coupling end 111c is coupled of the spring element 111.
Therefore position of the device second member 235, and particularly of the second magnetic sensor element (i.e., the sensor arrangement 235b), is substantially integral with the tub 107 of the laundry machine 100.
In other words, the load sensing device 200 according to an embodiment of the present invention is arranged to be coupled with a suspension element 111 with the device first member 210 associated to a first portion of said suspension element (i.e., the upper coupling end 111a) and with the device second member 235 associated to a second portion of the suspension element 111 (i.e., the lower coupling end 111c) - even though the vice versa is not excluded.
It should be noted that such arrangement allows a reliable connection of all load sensing device components, particularly of the of the device first member 210 and the device second member 235, being the latter connected to the same suspension element 111. Thus, any change of length (i.e., any extension/compression) of the suspension element 111 causes a change of distance (i.e., a displacement) between the first and second member of the load sensing device 200 and thereby between said first and the second sensor elements 215 and 255.
Thanks to such arrangement an improved reliability of the signal acquired is achieved since the load sensing device 200 is able to follow the movement/misalignments of the suspension element
It should be noted that, in further embodiments of the present invention (not shown), nothing prevents to invert the position of the first and the second sensor elements, e.g. a magnetic field sensor could be provided in the device first member while one or more permanent magnets could be provided in the device second member.
In a preferred embodiment of the invention, a diameter of the tubular body 210a of the device first member 210 is smaller than a diameter of the (cylindrical) space defined by the sequence of stacked spring coils 111b of the spring element 111.
Moreover, the coupling protrusions 225 are designed to engage the upper spring coil 220a in such a way to allow the device first member 210 to rotate about the two contact points between the protrusions 225 and the upper spring coil 220a. Thanks to the arrangement of the load sensing device 200 just described, the axis of the load sensing device 200 may rotate with respect to the axis of the suspension element 111, particularly during extension and compression thereof, while the device first member 210 and the device second member 235 remain axially aligned (due to the precision between the cavity 237 and the sliding portion 235a).
In other words, the device first member 210 is free of rotating around a fulcrum defined by a connection point between said the coupling protrusions 225 and said suspension element 111.
It should be noted, that in case two or more coupling protrusions 225 are provided, the disposition of the coupling protrusions 225 on the top end 210b of the tubular body 210a of the device first member 210 is designed in order to ensure that the load sensing device 200 is able to rotate with respect to the axis of the suspension element 111, particularly during extension and compression thereof.
For example, in the load sensing device 200 the two the protrusions 225 are arranged on a same half of the top end 210b of the tubular body 210a, thus allowing at least the device first member 210 (and, generally, the whole load-sensing device 200) to rotate with respect to the suspension element 111, particularly in case of non-linear deformations (i.e., along directions different than the axis of the suspension element 111).
Furthermore, a precision of the coupling between the device first member 210 and the device second member 235 is greater than a precision between the device first member 210 and the diameter of the (cylindrical) space defined by the sequence of stacked spring coils 111b of the spring element 111.
In other words, a difference between a diameter of the cavity 237 and a diameter of the sliding portion 235a (which is inserted in the former) is substantially smaller than a difference between the diameter of the space defined by the sequence of stacked spring coils 111b of the spring element 111 and a (external) diameter of the tubular body 210a.
For example, the difference between a diameter of the cavity 237 and a diameter of the sliding portion 235a is smaller than the difference between the diameter of the space defined by the sequence of stacked spring coils 111b of the spring element 111 and the diameter of the tubular body 210a of a factor comprised between 5 and 30, such as for example 20 - e.g., the difference between a diameter of the cavity 237 and a diameter of the sliding portion 235a is 0.05mm (or less) while the difference between the diameter of the space defined by the sequence of stacked spring coils 111b of the spring element 111 and the diameter of the tubular body 210a is 1mm (or more).
Thus, the play between the load sensing element 200 and the sequence of stacked spring coils 111b of the spring element 111 is substantially greater than a play between the tubular body 210a and the sliding portion 235a of the load sensing device 200.
Advantageously, capability of the load sensing element 200 or rotating with respect to the sequence of stacked spring coils 111b (thanks to the coupling protrusions 225) together with the play between the load sensing device 200 and the sequence of stacked spring coils 111b greater than the play between the tubular body 210a and the sliding portion 235a of the load sensing device 200, allows the load sensing device to substantially compensate the components of deformation of the spring element 111 occurring along axes different than the axis of the load sensing element 200 (e.g., transversal to the direction of the movement of the sliding portion 235a within the tubular body 210a).
In this way, it is possible to obtain a highly accurately measuring of displacements (e.g., in the order of the tenth to hundredth of millimeters) between magnets 215 and the sensing arrangement 235b that is substantially unaffected by the components of deformations of the spring element 111 occurring along axes different than the axis of the load sensing element 200.
During operation the load sensing device 200 may be used to evaluating a weight of laundry items comprised in the drum 110 of the laundry machine 100.
As laundry items are loaded into the drum 110 contained inside the tub 107 of the laundry machine 100, the weight of the laundry items causes the tub 107 to move downward.
As known, a length of the downward movement of the tub 107 is proportional to the weight of the laundry items provided in the drum 110 of the laundry machine 100.
Such displacement of the tub 107 due to the weight of the laundry items causes a corresponding elongation in the suspension element 111 and a corresponding compression in the dampening elements 112.
Moreover, the downward movement of the tub 107 causes the device second member 235 to rigidly move downward according to the extension of the sequence of stacked spring coils 111b of the spring element 111. In other words, a length of the displacement from a rest position - i.e., corresponding to a unloaded condition of the drum 110 and to a rest position of the suspension element 111 - of the device second member 235 substantially corresponds to the length of the downward movement of the tub 107 due to the weight of the laundry items loaded into the drum 110 of the laundry machine 100.
The relative movement between the permanent magnets 215 and the sensor arrangement 235b affects an operating electric parameter, e.g. an electric current value, of the magnetic field sensor 250 to an extent related to the length of the displacement.
The control system 150 of the laundry machine 100 is arranged to evaluate a weight of the laundry items provided in the drum 110 of the laundry machine by analyzing a corresponding signal provided by the sensor arrangement 235b based on the electromagnetic interaction between the first and second sensor elements (i.e., the permanent magnets 215 and the magnetic field sensor 250) advantageously processed by the electronic managing element 257.
The components of the load sensing device 200 according to the present invention has a structure that may be simply and cheaply manufactured (e.g., in moulded plastic material) and assembled.
Moreover, the load sensing device 200 may be simply provided in a laundry machine 100 without the need of specific tools or particular training for technicians. Indeed, the load sensing device 200 may be simply coupled with a suspension element 111 of the laundry machine 100 by firstly inserting the device first member 210 into the (cylindrical) space defined by the sequence of stacked spring coils 111b until the coupling protrusions 225 engage the upper spring coil 220 of the sequence of stacked spring coils 111b.
Afterwards, the device second member 235 is inserted into the cavity 237 of the tubular body 210a of the device first member 210 until the hooked protrusion 247 engages the lower spring coil 220b of the sequence of stacked spring coils 111b.
Finally, the suspension element 111 with the load sensing device 200 is mounted in its operating position in the laundry machine 100. Particularly, the suspension element 111 (carrying the load sensing device 200) is coupled with the casing retaining element 113c of the casing 105 and with the tub retaining element 113t of the tub 107 by means of the upper coupling end 111a and lower coupling end 111c, respectively.
It should be noted that the load sensing device 200 may be provided to a laundry machine 100 without requiring the latter to comprise dedicated housing or receptacles. In other words, the load sensing device 200 is suited to be added to different laundry machines typologies without any (or minimum) changes to the design thereof and/or the load sensing device 200 is suited for easy retrofitting/substitution in deployed laundry machines 100.
Turning now to Figures 3A to 3F , a different load sensing device 300 according to a second embodiment of the invention is shown. The load sensing device 330 is also adapted to be installed at a suspension element 111 of the laundry machine 100.
The load sensing device 300 differs from the load sensing device 200 described above in what follows, where similar parts are denoted by similar reference and their description is not repeated for the sake of brevity.
The device second member 335, according to the second embodiment of the invention, comprises a sliding portion 335a and a clamping portion 360.
The sliding portion 335a is shaped in such a way to fit the cavity 330 of the tubular body 310a of the first device member 310. Particularly, the sliding portion 335a is shaped in such a way to slidably couple with the tubular body 310a of the device first member 310, substantially as described above with respect to the sliding portion 335a and the tubular body 310a.
The clamping portion 360 is arranged for connecting with the tub 107 of the laundry machine 100. Preferably, the clamping portion 360 is a coupling protrusion of the device second member 335 that protrudes from the bottom of the sliding portion 335a and extends downwards.
For example, the clamping portion 360 is provided coupled with lower coupling end 111c of the suspension element 111, e.g. the clamping portion 360 is provided astride the lower coupling end 111c. The clamping portion 360 is preferably adapted to be fitted into the same eyelet 305 of the tub retaining element 113t wherein the hook of the lower coupling end 111c of the suspension element 111 is fitted into. Alternatively, the clamping portion 360 is adapted to be fitted into an eyelet (not shown in the drawings) of an additional dedicated tub retaining element.
As in the load sensing device 200, in the load sensing device 300, the device first member 310 is fixed to the upper spring coil 320a of the sequence of stacked spring coils 111b - which is substantially integral with the upper coupling end 111a of the spring element 111 and thus with the casing 105 of the laundry machine 100 to which the upper coupling end 111a is coupled.
Therefore, the position of the device first member 310, and particularly of the first sensor element (i.e., the permanent magnets 315), is substantially integral with the casing 105 of the laundry machine 100.
Conversely, the device second member 335 is fixed to the tub 107 (i.e., the second device member 335 is substantially integral with the tub 107) as the lower coupling end 111c of the suspension element 111 (to which the clamping portion 360 is coupled), the position of the second sensor, i.e. the magnetic field sensor 350, varies according the oscillations of the tub 107, as the suspension element 111 elongates and compresses according to the oscillations of the tub 107.
In other words, the load sensing device 300 according to an embodiment of the present invention is arranged to be coupled with a suspension element 111 with the device first member 310 associated to a first portion of said suspension element (i.e., the upper coupling end 111a) and with the device second member 335 associated to a second portion of the suspension element (i.e., the lower coupling end 111c) - even though the vice versa is not excluded.
Thanks to such arrangement, any change of length (i.e., any extension/compression) of the suspension element 111 causes a change of distance (i.e., a displacement) between the first and second members 310 and 335 of the load sensing device 300 and thereby between said first and the second sensor elements 315 and 350.
Thanks to such arrangement an improved reliability of the signal acquired is achieved since the load sensing device 200 is able to follow the movement/misalignments of the suspension element
It should be noted that, in further embodiments of the present invention (not shown), nothing prevents to invert the position of the first and the second sensor elements, e.g. a magnetic field sensor could be provided in the device first member while one or more permanent magnets could be provided in the device second member.
During operation the load sensing device 300 may be used to evaluating a weight of laundry items comprised in the drum 110 of the laundry machine 100 substantially as described above with respect to load sensing device 200 and with the same advantages.
In a preferred embodiment of the load sensing device 300 according to the invention, a diameter of the tubular body 310a of the device first member 310 is smaller than a diameter of the (cylindrical) space defined by the sequence of stacked spring coils 111b of the spring element 111.
Moreover, the coupling protrusions 325 are designed to engage the upper spring coil 320a in such a way to allow the device first member 310 to rotate about the two contact points between the protrusions 325 and the upper coil spring 320a.
Thanks to the arrangement of the load sensing device 300 just described, the load sensing device 300 may rotate with respect to the axis of the suspension element 111, particularly during extension and compression thereof, while the device first member 310 and the device second member 335 remain axially aligned (due to the precision between the cavity 337 and the sliding portion 335a).
In other words, the device first member 310 is free of rotating around a fulcrum defined by a connection point between said the coupling protrusions 325 and said suspension element 111.
Moreover, the load sensing device 300 may be simply provided in a laundry machine 100 without the need of specific tools or training for technicians. Indeed, the load sensing device 300 may be simply coupled with a suspension element 111 of the laundry machine 100 by simply inserting the device first member 310 into the sequence of stacked spring coils 111b until the coupling protrusions 325 engage the upper spring coil 320 of the sequence of stacked spring coils 111b.
Afterwards, the device second member 335 is inserted into the cavity 337 of the tubular body 310a of the device first member 310, at the same time the clamping portion 360 is coupled with the lower coupling end 111c of the suspension element 111.
It should be noted that also the load sensing device 300 may be provided to a laundry machine 100 without requiring the latter to comprise dedicated housing or receptacles. In other words, the load sensing device 300 is suited to be added to different laundry machines typologies without any (or minimum) changes to the design thereof and/or the load sensing device 300 is suited for easy retrofitting/substitution in deployed laundry machines 100.
Naturally, in order to satisfy local and specific requirements, a person skilled in the art may apply to the solution described above many logical and/or physical modifications and alterations.
For example, in a further embodiment of the present invention (not shown) a device second member may be provided with both a hooked protrusion, for coupling with a lower spring coil of the sequence of stacked spring coils, and a clamping portion, for coupling with the lower coupling end of the suspension element.
Furthermore, in alternative embodiments (not shown) a stand-alone load sensing device may be provided. The stand-alone load sensing device differs from the load sensing device 300 in what follows.
The stand-alone load sensing device may be directly connected to both the casing and to the tub of a laundry machine independently from any suspension elements.
For example a device first member of the stand-alone load sensing device may be provided with one or more modified clamping protrusions adapted to engage a respective retaining element provided in a top portion of the casing of the laundry machine, while the device second member of the stand-alone load sensing device may be connected to a respective retaining element provided in the tub of the laundry machine by means of the clamping portion.

Claims

A laundry machine (100) for treating laundry items, the laundry machine (100) comprising:
a cabinet (105) for accommodating components necessary for the operation of the laundry machine (100);

a washing tub (107) comprising a rotatable drum for containing laundry items, the washing tub (107) being enclosed by the cabinet (105) such that it can be moved in a floating manner inside said cabinet;

at least one suspension element (111) comprising a first portion (220a, 111a; 320a, 111a) associated to the cabinet (105) and a second portion (220b, 111c; 111c) associated to the washing tub (107) for movably coupling the tub (107) with the cabinet (105) of the laundry machine (100), and

a load sensing device (200; 300) for measuring a physical value related to the weight of laundry items provided in the washing tub (107), wherein the load sensing device (200; 300) comprises a device first member (210; 310) comprising a first sensor element (215; 315) and a device second member (235; 335) comprising a second sensor element (235b; 335b)

wherein the load sensing device (200; 300) is coupled with the at least one suspension element (111) with the device first member (210; 310) associated to the first portion (220a, 111a; 320a, 111a) of said suspension element (111) and with the device second member (235; 335) associated to the second portion (220b, 111c; 111c) of the suspension element (111) or vice-versa, thereby the change of length of the suspension element (111) causes the change of distance between said first and the second sensor elements
characterized in that

the suspension element (111) comprises a upper coupling end (111a) for coupling with the cabinet (105) of the laundry machine (100), a sequence of stacked spring coils (111b), and a lower coupling end (111c) for coupling with the washing tub (107),

wherein the device first member (210; 310) comprises at least one coupling protrusion (225; 325) protruding from the device first member (210; 310), the at least one coupling protrusion (225; 325) being adapted to engage with the suspension element (111).
The laundry machine (100) according to claim 1, wherein the first sensor element (215; 315) comprises at least one permanent magnet (215; 325).
The laundry machine (100) according to claim 2, wherein the second sensor element (235b; 335b) comprises at least one magnetic field sensor (255; 355).
The laundry machine (100) according to any one of the preceding claims, wherein the second sensor element (235b; 335b) comprises a sensor arrangement (235b) provided with an electronic board (250; 350).
The laundry machine (100) according to claim 4, further comprising a control system (150) configured for controlling the operation of the laundry machine (100), and
wherein the electronic board (250; 350) further mounts electronic components for exchanging signals with the control system (150) of the laundry machine (100).
The laundry machine (100) according to any one of the preceding claims, wherein the device first member (210; 310) and the device second member (235; 335) are slidably coupled one another.
The laundry machine (100) according to claim 6, wherein the device first member (210; 310) comprises a tubular body (210a; 310a) which delimits a cavity (230; 330), the cavity (230; 330) being adapted to receive at least a portion of the second device section (235).
The laundry machine (100) according to claim 7, wherein the device second member (235; 335) further comprises a sliding portion (235a; 335a) shaped to slidably fit the cavity (230; 330) delimited by the tubular body (210a; 310a) of the device first member (210; 310).
The laundry machine (100) according to claim 8, wherein the first sensor element (215; 315) is provided in the tubular body (210a; 310a) of the device first member (210; 310) and
wherein the second sensor element (235b; 335b) is provided in the sliding portion (235a; 335a) of the device second member (235; 335), or vice-versa
the second sensor element (235b; 335b) is provided in the tubular body (210a; 310a) of the device first member (210; 310) and
wherein the first sensor element (215; 315) is provided in the sliding portion (235a; 335a) of the device second member (235; 335).
The laundry machine (100) to any one of the preceding claims, wherein the suspension element (111) comprises a upper coupling end (111a) for coupling with the cabinet (105) of the laundry machine (100), a sequence of stacked spring coils (111b), and a lower coupling end (111c) for coupling with the washing tub (107), and
wherein the device second member (235; 335) comprises at least one coupling protrusion (247) protruding from the device second member (235; 335), the at least one coupling protrusion (247) being adapted to engage with the suspension element (111).
The laundry machine (100) according to any one of the preceding claims, wherein the device first member (210; 310) is associated to the first portion (220a, 111a; 320a, 111a) or to the second portion (220b, 111c; 320b, 111c) of the suspension element (111) or vice-versa through connection means (225; 325) allowing the rotation of said first portion (220a, 111a; 320a, 111a) around the fulcrum defined by the connection point between said connection means (225; 325) and said suspension element (111).
Method of assembly a laundry machine (100) comprising:
providing a cabinet (105) for accommodating components necessary for the operation of the laundry machine (100);

providing a washing tub (107) comprising a rotatable drum for containing laundry items,

providing at least one suspension element (111) comprising a first portion and a second portion;

associating the first portion of said suspension element (111) to the cabinet (105);

associating the second portion of said suspension element (111) to the washing tub (107), thereby movably coupling the tub (107) with the cabinet (105) of the laundry machine (100) such that it can be moved in a floating manner inside said cabinet, and

providing a load sensing device (200; 300) for measuring a physical value related to the weight of laundry items provided in the washing tub (107), wherein the load sensing device (200; 300) comprises a device first member (210; 310) comprising a first sensor element (215; 315) and a device second member (235; 335) comprising a second sensor element (235b; 335b)
characterized in that

providing a load sensing device (200; 300) comprises:
coupling the device first member (210; 310) with the first portion of said suspension element (111), and

coupling the device second member (235; 335) with the second portion of said suspension element (111), or

vice-versa coupling the device second member (235; 335) with the first portion of said suspension element (111), and

coupling the device first member (210; 310) with the second portion of said suspension element (111).
The method according to claim 12, wherein the at least one suspension element (111) further comprises a sequence of stacked spring coils (111b) interposed between said first portion and second portion of said suspension element (111), the sequence of stacked spring coils (111b) delimiting an inner space, and
the device first member (210; 310) of the load sensing device (200; 300) further comprises at least one coupling protrusions (225; 325), and
wherein the coupling the device first member (210; 310) with the first portion of said suspension element (111) comprises:
inserting the device first member (210; 310) into the inner space defined by the sequence of stacked spring coils (111b) until said coupling protrusion (225; 325) engage an upper spring coil (220a; 320a) of the sequence of stacked spring coils (111b).
The method according to claim 13, wherein the device second member (235) further comprises a respective coupling protrusion (247), and
the device first member (210) of the load sensing device (200) further comprises a cavity (230), and
wherein coupling the device second member (235) with the second portion of said suspension element (111) comprises
inserting the device second member (235) into the cavity (230) of the device first member (210) until the respective coupling protrusions (247) engages a lower spring coil (220b) of the sequence of stacked spring coils (111b).