Patent Description:
Known laundry driers comprise a cabinet, typically parallelepiped-shaped, containing rotatable drum for housing the laundry to be dried. A flow of hot air is circulated through the drum, so as to dry the laundry contained therein.

A heating system is provided for heating the air; the heating system can comprise a heat pump system or one or more electrical heaters, both housed within the cabinet, externally to the drum.

In known laundry driers, there is the problem that, since the drum is rotatable, it is difficult transmitting electrical energy from the "not rotatable" parts of the laundry drier (e.g. the cabinet, or components fixed thereof) to the internal of the drum; this layout, therefore, limits the possibility to mount in the drum electrical devices for treating the laundry and/or for detecting related physical parameters, which require to be electrically powered.

<CIT> Al discloses a wireless communication assembly including a driver module connected to a first portion of a machine, such as a laundry machine, and a receiver module connected to a second portion of the machine, such as a rotatable drum. The first module includes a primary coil configured to generate an electromagnetic field and a first wireless transceiver. The second module includes a secondary coil configured to convert energy within the electromagnetic field into electric power, and a second wireless transceiver powered by the secondary coil and configured to communicate with the first wireless transceiver. One or more sensors may be positioned within the drum to measure various conditions. The receiver module may be powered by the secondary coil and when powered on, may communicate data from the one or more sensors to the first module. Other systems according to the prior art are also known from <CIT>, <CIT>, <CIT> and <CIT>.

It is an object of the present invention to provide a laundry drier which does not present above mentioned problems, and which allows to treat the laundry in a more dedicated, localized, and effective way.

Above object is solved by a laundry drier comprising:.

It is underlined that "component unmovable with respect to the cabinet" means that this component, or element, is fixed to the cabinet, or in other words that this component can't move (e.g. can't rotate, translate, oscillate, etc.) with respect to the cabinet.

Advantageous embodiments are defined by the dependent claims.

Other advantages and features of a laundry drier according to the present invention will be clear from the following detailed description, provided only as a non limitative example, in which:.

In the figures same parts are indicated with the same reference numbers.

In <FIG>, an advantageous example of a laundry dryer <NUM> is illustrated, comprising a cabinet <NUM>, preferably but not necessarily parallelepiped-shaped, and a drying chamber, such as a drum <NUM>, for example having the shape of a hollow cylinder, for housing the laundry, not illustrated, to be dried.

The drum <NUM> is rotatably supported within the cabinet <NUM>, so that it can rotate around a, preferably horizontal, rotation axis R (in alternative embodiments, rotation axis may be tilted).

Access to the drum <NUM> is achieved for example via a door <NUM>, preferably hinged to cabinet, which can open and close a loading/unloading opening 4a realized on the cabinet <NUM> itself.

Cabinet <NUM> generally includes a front wall 20a, a rear wall 20b, two sidewalls, not illustrated, all preferably mounted on a basement <NUM>.

Cabinet <NUM> may include also a top wall <NUM>. Preferably, the basement <NUM> is realized in plastic material, and more preferably it is molded via an injection molding process. Advantageously, basement <NUM> is hollow, and it preferably contains one or more electromechanical components of the laundry drier <NUM>, as will be better explained in the following.

Laundry dryer <NUM> also preferably comprises an electrical motor assembly, not illustrated, for rotating, on command, the drum <NUM> along its axis R.

Laundry dryer <NUM> may include an electronic control unit (for example the of the type numbered <NUM> in <FIG>) which controls both the electrical motor assembly and other components of the dryer <NUM>, to perform, on command, one of the drying cycles preferably stored in the same central control unit. The programs as well other parameters of the laundry dryer <NUM>, or alarm and warning functions can be set and/or visualized in a control panel <NUM>, preferably positioned in a top portion of the dryer <NUM>, such as above door <NUM>.

The drum <NUM> includes a mantle 50c, having preferably a substantially cylindrical/tubular shape, which is preferably made of metal, and is arranged inside the cabinet <NUM> and adapted to rotate around the rotational axis R. The drum <NUM> has a first end 50a facing the loading/unloading opening 4a, and a second end 50b facing the rear wall 20b.

Drum <NUM> may be an open drum, i.e. both ends 50a and 50b can be opened (as in <FIG>), or it may include a back wall (not shown in the attached Figures) fixedly connected to the mantle and rotating with the latter.

In order to rotate, one or more support elements for the rotation of the drum <NUM> are provided; these support elements include one or more roller <NUM> (preferably two or more), more preferably rotatably associated to the basement <NUM>. Preferably the roller(s) <NUM> are positioned at the front and/or at the back of the drum <NUM>; more preferably, two rollers <NUM> are positioned at the front and two rollers <NUM> are positioned at the back of the drum <NUM>.

In another advantageous embodiment, not illustrated, a drum shaft, connected to a rear end of the drum <NUM>, can support the latter.

Laundry dryer <NUM> advantageously comprises a process air circuit <NUM>, indicated in <FIG> by a plurality of black arrows <NUM>, showing the path flow of a process air stream through the dryer <NUM>.

The process air circuit <NUM> advantageously comprises the drum <NUM> and a duct 24a in the basement <NUM>.

The laundry drier <NUM> also advantageously comprises a fan or blower <NUM> for circulating process air through the process air circuit <NUM>, and in particular through the drum <NUM>.

The laundry drier <NUM> advantageously comprise a heating system producing heat for drying the laundry.

In the advantageous embodiment of <FIG>, the heating system comprises a heat pump system arranged for removing humidity from the process air exhausted from the drum <NUM>, and for heating such air before it re-enters the drum <NUM>, in a condition suitable to further remove humidity from laundry. The heat pump system advantageously comprises a first heat exchanger (called also condenser) <NUM> and a second heat exchanger (called also evaporator) <NUM>. Heat pump system <NUM> advantageously comprises a refrigerant closed circuit, not illustrated, in which a refrigerant fluid flows.

Heat pump system also advantageously comprises a compressor <NUM>, receiving refrigerant in a gaseous state from the evaporator <NUM>, and supplying it in a liquid stated to the condenser <NUM>, thereby closing the refrigerant cycle. Preferably, in correspondence of evaporator <NUM>, the laundry dryer <NUM> may include a condensed-water canister (not illustrated) which collects the condensed water produced, when the laundry dryer <NUM> is in operation, in the evaporator <NUM> by condensation of the surplus moisture in the process air stream arriving from the drum <NUM>. Preferably, the canister is located at the bottom of the evaporator <NUM>. Preferably, through a connecting pipe and a pump (not shown in the drawings), the collected water is sent in a reservoir located preferably in correspondence of the highest portion of the dryer <NUM> so as to facilitate a comfortable manual discharge of the water by the user of the dryer <NUM>.

The condenser <NUM> and the evaporator <NUM> of the heat pump system are preferably housed within the duct 24a formed in the basement <NUM>.

In case of a condense-type dryer - as depicted in <FIG> - where the process air circuit <NUM> is a closed loop circuit, the condenser <NUM> is preferably located downstream (with reference to the air flow direction) of the evaporator <NUM>.

Advantageously, the air exiting the drum <NUM> reaches the evaporator <NUM>, which cools down and dehumidifies the process air, and then it enters the condenser <NUM>, where it is warmed up by the heat pump system before re-entering the drum <NUM>. Advantageously the laundry drier <NUM> comprises a frontal wall or flange <NUM>, facing the first end 50a of the drum <NUM>, and preferably comprising the loading/unloading opening 4a.

Advantageously, the first end 50a of the drum <NUM> abuts against a first cylindric gasket 22a, preferably made of felt, attached to the wall or flange <NUM>.

Advantageously the frontal wall or flange <NUM> comprises a conduit <NUM>, fluidly connected to the duct 24a of the basement <NUM>, and comprised in the process air circuit <NUM>.

Preferably a removable lint filter <NUM> is provided in the process air circuit <NUM> (preferably, but not necessarily, in the conduit <NUM> of the frontal wall or flange <NUM>); the lint filter <NUM> is arranged for intercepting the air flow exiting the drum <NUM> and for collecting lint particles contained therein.

Advantageously the laundry drier <NUM> comprises a rear pipe <NUM>, fluidly connecting the second end 50b of the drum <NUM> to the duct 24a of the basement <NUM>. Preferably, the second end 50b of the drum <NUM> abuts against a second cylindric gasket 25a, preferably made of felt, attached to the rear pipe <NUM>.

The laundry drier <NUM> comprises a wireless power supply transmitter unit <NUM>, fixed to the cabinet <NUM> or to a component of the laundry drier unmovable with respect to the cabinet <NUM>; in the example of <FIG>, the wireless power supply transmitter unit <NUM> is advantageously fixed to the frontal wall or flange <NUM>.

It is underlined that "component unmovable with respect to the cabinet <NUM>" means that this component, or element, is fixed to the cabinet, or in other words that this component can't move (e.g. can't rotate, translate, oscillate, etc.) with respect to the cabinet <NUM>.

The wireless power transmitter unit <NUM> is advantageously electrically connected, preferably wired, to the electric system, not illustrated, of the laundry drier <NUM>; the electric system is connectable, for example, to the electric mains, not illustrated, of the building where the laundry drier <NUM> is installed, so as to be power supplied by such electric mains. Advantageously the laundry drier <NUM> comprises a wireless receiver power unit <NUM>, mounted in/on the drum <NUM>.

The wireless power transmitter unit <NUM> is electromagnetically coupled with the wireless power receiver unit <NUM>, for transmitting electric power to the latter.

In the advantageous example of <FIG>, the wireless power receiver unit <NUM> is mounted on the first end 50a of the drum 50a, facing the frontal wall or flange <NUM>.

In the advantageous example of <FIG>, the wireless power supply transmitter unit <NUM> is mounted on the frontal wall or flange <NUM>, so as to face the wireless power receiver unit <NUM>. The wireless receiver power unit <NUM> and the wireless power supply transmitter unit <NUM> are annular shaped, centred with the drum centre and mounted radially parallel respectively on the cabinet <NUM> or component <NUM> of the laundry drier <NUM> unmovable with respect to the cabinet <NUM>) to which the wireless power transmitter unit <NUM> is fixed, and on the drum <NUM>.

Advantageously, the drum <NUM> is provided with one or more lifters <NUM> (four in the example of <FIG>), to lift the laundry in the drying cycle.

In a preferred embodiment, each lifter <NUM> comprises or encloses a heating element <NUM>.

The wireless power receiver unit <NUM>, preferably through electric wires 63a electrically supplies the heating elements <NUM>.

<FIG> schematically shows a sectional view of an advantageous example of a lifter <NUM>. The heating element <NUM> is advantageously integrated/contained in the lifter <NUM>; in an advantageous embodiment, the heating element can be cylindrical shaped, and have the same length of the lifter <NUM> in axial direction.

Preferably the lifters <NUM> have a perforated structure (i.e. their walls can have openings), so as to allow air to pass through and be heated by the heater <NUM>.

In a preferred embodiment, the heaters <NUM> can be used as the heating system of the laundry drier <NUM>, i.e. for heating the laundry contained in the drum <NUM>.

In another advantageous embodiment, in which another heating system, for example a heat pump system, is provided in the laundry drier <NUM>, the heater <NUM> can work together with the other heating system, for example for speeding up the heating process (and thus reducing the drying cycle time).

Preferably, the wireless power receiver unit <NUM> is fixed parallel in radial direction opposite the wireless power transmitter unit <NUM>.

In <FIG> it is shown a sectional view of an advantageous example of the power transmitter unit <NUM> and receiver unit <NUM>.

Advantageously, the power transmitter unit <NUM> has a transmission coil <NUM> which is electromagnetically coupled to a reception coil <NUM> of the power receiver unit <NUM>. They can be advantageously integrated into the enclosing material <NUM>, <NUM>, and they can advantageously have respectively magnetic sheets <NUM> and <NUM> that provide the side magnetic shield to the sides external to the coupling area and improve the magnetic coupling between the two coils <NUM> and <NUM>.

Preferably, the wireless power receiver unit <NUM> and the wireless power transmitter unit <NUM> are parallel, centred with respect to the drum <NUM> centre in order to maximize the electromagnetic coupling, as shown in <FIG>.

The wireless power receiver unit <NUM> could be fixed in a U shaped opening formed in the drum <NUM> external periphery, while the power transmitter unit could have its side <NUM> fixed with screw or glued to the wall of the cabinet <NUM>, or, as in <FIG>, to the frontal wall of flange <NUM>.

Advantageously the laundry drier <NUM> comprises a control unit <NUM>.

As shown in <FIG>, advantageously the control unit <NUM> may generate an oscillating voltage by switching elements <NUM> that supply the transmission coil <NUM> of the power transmitter unit <NUM> coupled to the reception coil <NUM> of the power receiver unit <NUM>. The voltage induced in the coil <NUM> is preferably rectified and conditioned in the coil interface block <NUM>, and preferably brought, preferably with wires, to the heating elements <NUM>, preferably connected in series. The components of the interface block <NUM> could be preferably integrated in the power receiver unit <NUM>.

Advantageously, the appliance control unit <NUM> manages the complete drying operations, controlling the drum motor rotation speed as well as the other electric/electronic components of the laundry drier <NUM>. Preferably, the appliance control units <NUM> can measure the temperature in the drum <NUM>, and generate the proper voltage supplying the heating elements, for example through a switching element <NUM>. Another advantageous embodiment is shown in <FIG> where the power receiver unit <NUM> has multiple coils <NUM>, each coil <NUM> supplying through its own interface block <NUM> a heating element <NUM>.

One further advantageous embodiment is shown in <FIG>. In this embodiment on the drum <NUM> there is fixed an interface unit <NUM>, together with the power receiver unit <NUM> and the heating element <NUM>. The interface unit <NUM> can be supplied by a dedicated reception coil <NUM> of the receiver unit <NUM>, as shown in <FIG>, or it could be connected in parallel to the reception coil <NUM> supplying the heating elements <NUM>.

The interface unit <NUM> has advantageously a wireless connection <NUM> to transfer measurement data to the appliance control unit <NUM>.

In particular, the interface unit <NUM> could transfer to the appliance control unit <NUM> measured temperatures <NUM> from temperature measurement elements positioned in the lifters <NUM>.

It would allow to design drying cycles based on the real temperature measured in the drum <NUM>.

The interface unit <NUM> could be advantageously positioned integrated in the isolating support material <NUM> of the power receiver unit <NUM>. Advantageously the interface unit <NUM> could sense and send additional measurement parameters, not only temperatures <NUM>, but also e.g. unbalance, providing all needed sensing information <NUM> to the appliance control unit <NUM>.

Advantageously, the wireless power receiver unit can supply power to any type of electric element mounted in/on the drum or fixed to the drum, including heating elements, signal transmission and/or reception elements (like wireless data transmission and/or reception devices) and sensor elements (like temperature sensors, humidity sensors, movement sensors such as speed or acceleration sensors).

Claim 1:
A laundry drier (<NUM>) comprising:
- a cabinet (<NUM>),
- a drum (<NUM>) rotatably mounted inside the cabinet (<NUM>),
- one or more support elements (<NUM>) for the rotation of the drum (<NUM>), wherein said one or more support elements include one or more rollers (<NUM>),
- at least one electric element (<NUM>, <NUM>) mounted in the drum (<NUM>),
- a wireless power transmitter unit (<NUM>) fixed to said cabinet (<NUM>) or to a component (<NUM>) of said laundry drier (<NUM>) unmovable with respect to said cabinet (<NUM>),
- a wireless power receiver unit (<NUM>) mounted in/on said drum (<NUM>),
wherein said wireless power transmitter unit (<NUM>) is electromagnetically coupled with said wireless power receiver unit (<NUM>), for transmitting electric power to the latter, and
wherein said wireless power receiver unit (<NUM>) is electrically coupled with said at least one electric element (<NUM>, <NUM>), for supplying electric power to the latter,
characterized in that
said wireless power receiver unit (<NUM>) and said wireless power transmitter unit (<NUM>) are annular shaped, centred with the drum (<NUM>) centre, and mounted radially parallel respectively on said cabinet (<NUM>), or on said component (<NUM>) of said laundry drier (<NUM>) unmovable with respect to said cabinet (<NUM>), and on said drum (<NUM>).