EP2822440B1

EP2822440B1 - Wash assembly applied to a washing machine and/or drying machine

Info

Publication number: EP2822440B1
Application number: EP13720565.4A
Authority: EP
Inventors: Paolo Ravedati; Enzo Brignone; Giovanni Giordano; Lino CASO
Original assignee: Bitron SpA
Current assignee: Bitron SpA
Priority date: 2012-03-08
Filing date: 2013-03-07
Publication date: 2016-05-04
Anticipated expiration: 2033-03-07
Also published as: ES2587940T3; CN104284620A; PL2822440T3; CN104284620B; EP2822440A1; WO2013132458A1

Description

The present invention relates to an assembly, for alternate washing, to be installed between at least one arm supporting at least one rotary sprayer and the alternate wash assembly adapted to direct the water flow towards the various rotary sprayers, wherein a device is included which is adapted to control both said arm and said alternate wash assembly. Said assembly is applied to a washing and/or drying machine, e.g. a dishwasher.
Dishwashers are known which, for washing crockery in the wash chamber, comprise at least two rotary sprayers, e.g. a rotary sprayer for washing the upper portion of the chamber, in particular crockery arranged on an upper rack, if available, and a lower rotary sprayer for washing the lower portion of the same wash chamber, in particular crockery arranged on a lower rack. Preferably, said washing machines comprise two racks, i.e. a first upper rack and a second lower rack, each associated with at least one rotary sprayer.
Normally the rotary motion of the sprayer is attained by exploiting the inclination of the water jet generated by a plurality of nozzles. In fact, the nozzles are appropriately arranged in a manner such that the force of the exiting water generates an equal and opposite force onto the sprayer, which will thus rotate, e.g. about a vertical axis.
Among the rotary sprayers installed in a wash chamber, the one that washes crockery with most difficulty is the lower rotary sprayer that must wash the lower rack, where crockery particularly difficult to wash is normally placed, such as pots, dishes and cutlery. Such pieces of crockery give rise to several wash problems because they may be heavily encrusted or may have shapes that do not allow water to be properly incident on their surfaces.
A further problem observed during the washing for the lower rotary sprayer relates to the possibility that the latter might strike against improperly positioned crockery, such as cutlery, which might obstruct the sprayer as it turns, thus preventing it from correctly washing some areas of the rack.
To improve the washing, the lower rotary sprayer comprises nozzles having greater diameters than the other rotary sprayers, so as to ensure a stronger impact of the water against the crockery, resulting however in higher water consumption.
Loading pieces of crockery such as pots creates another problem for sprayer rotation. When pots are not properly arranged, in fact, their shape may cause the water jet to splash back from them, sometimes in a direction opposite to the rotary motion of the sprayer, thus reducing its revolution speed or even causing it to temporarily stop.
The above-described problems do not allow to obtain an optimal washing of the lower rack as the loaded crockery and/or the arrangement thereof varies, implying that some sections of the wash chamber and/or of the single rack may be washed better than the remaining portions of the rack and/or of the wash chamber.
Rotary sprayers are also known which are removably mounted to the bottom base of the wash chamber and which are adapted to rotate, under the hydrodynamic thrust of water exiting through a plurality of nozzles, about a vertical axis located at the centre of the wash chamber. Such a rotary sprayer for washing the central portion of the wash chamber comprises just a single water jet along said axis of rotation, thus reducing the cleaning power in the central part of the wash chamber.
Arms are also known, whereto at least one rotary sprayer may be secured in different manners. Normally, such arms are idle and are mounted on rolling bearings. Such arms are moved by the hydrodynamic thrust of water; in fact, the hydrodynamic thrust of water causes the sprayers to rotate and, through a satellite movement, also moves said arm. This solution does not allow to determine the position of the arm and, as a consequence, the position of the rotary sprayer within the wash chamber, in particular in which section of the rack it is located.
Arms are also known which, through suitable actuating means, are driven in a manner such as to move at least one rotary sprayer, associated with the arm, to different areas of the wash chamber in order to improve the cleaning action.
Normally, in order to direct the water towards the various rotary sprayers included in the wash chamber, dishwashers comprise an alternate wash assembly adapted to deviate and distribute fluid flows from an inlet, connected to a supply circuit, e.g. the water main, or from a closed circuit, to one or more outlets, connected to one or more hydraulic circuits, in turn connected to said one or more rotary sprayers.
Said alternate wash assembly is actuated by a motor that drives a selector which, depending on its rotation, opens and/or closes one or more hydraulic output circuits in accordance with a predetermined wash program that defines the portion of the wash chamber to be washed.
In the prior art, the arm is moved through an actuator which is independent of the electric motor comprised in the alternate wash assembly. This implies the impossibility of having the rotary sprayer stop at all the desired points, because the actuator only has two positions and can only cause the arm, and hence the rotary sprayer, to take two operating configurations. Arm movement devices are also known wherein said rotary sprayer moving arm is moved through an actuator. Such movement devices comprise a part of the motion transmission mechanism inside the wash chamber. This implies that such mechanism portions must be properly insulated to protect said transmission mechanism against corrosion induced by water and to avoid that dirt residues might deposit into sensitive portions of the device, which might lead to arm seizure. Such a solution is very costly.
Patent application EP 1 090 579 A1 discloses a revolving sprinkling assembly for dishwasher includes a sprinkler and a device for shifting said sprinkler consisting of a mobile support means for the sprinkler and an actuator means for driving the mobile support means. The latter may consist of a rotating shaft provided at the top with a transverse extension at whose free end there is pivoted the sprinkler, so that the axis of rotation of the latter is eccentric with respect to axis of rotation of the shaft, or consist of a translating duct slidably engaged onto a feed box. The shifting of the mobile support means is achieved through a toothed rim or a rack engaged with a gear driven into rotation by a thermo-actuator or by a motor.
It also known from the patent application EP 1 502 535 A2 an apparatus for controlling a washing flow of a dishwasher that can perform an upper washing, a lower washing, an alternate washing of upper and lower sides, and a concurrent washing of upper and lower sides for effective washing.
The patent application DE 10 2011 052846 A1 describes an automatic dishwasher having first and second sprayers located within a washtub, a diverter valve to selectively divert liquid flowing from the wash chamber between the first and second sprayers, and a drive system moving the first sprayer in the wash chamber.
The present invention aims at solving the above-mentioned technical problems of the prior art by providing an assembly for alternate washing to be applied to a washing and/or drying machine, wherein a single device is used which is capable of controlling both the arm on which the rotary sprayer is mounted and the alternate wash assembly.
One aspect of the present invention relates to a wash assembly having the features set out in the appended claim 1.
A further aspect of the present invention relates to a dishwasher having the features set out in the appended claim 11.
Auxiliary features of the assembly and of the dishwasher are set out in respective dependent claims appended hereto.
The features and advantages of the assembly and of the dishwasher according to the present invention will become more apparent from the following patent description of at least one embodiment thereof and from the annexed drawings, wherein:

Figure 1 shows a perspective view of the assembly according to the present invention;
Figure 2 shows an exploded view of the assembly of Fig. 1;
Figure 3A is a sectional side view of the assembly of Figure 1, in a first embodiment thereof;
Figure 3B is a perspective view of a preferred embodiment of the actuating device according to the present invention;
Figures 4A, 4B and 4C show the arm of the assembly according to the present invention, comprising a first embodiment of the torque limiting means; in particular, Figure 4A is an exploded view of the arm of the assembly according to the present invention, Figure 4B is a sectional side view of the same arm, Figure 4C is an exploded view of the torque limiting means in a first embodiment thereof;
Figures 5A, 5B and 5C show the arm of the assembly according to the present invention, comprising a second embodiment of the torque limiting means; in particular, Figure 5A is an exploded view of the arm of the assembly according to the present invention, Figure 5B is a sectional side view of the same arm, Figure 5C is an exploded view of the torque limiting means in a second embodiment thereof;
Figures 6A, 6B and 6C illustrate, in different views, the alternate wash assembly; in particular, Figure 6A is a top view of the alternate wash assembly; Figure 6B is a sectional view of a first embodiment of the alternate wash assembly; Figure 6C is an exploded view of a second embodiment of the alternate wash assembly, comprising fluid heating means;
Figures 7A and 7B show some alternative embodiments of the assembly according to the present invention; in particular, Figure 7A shows an assembly wherein the alternate wash assembly comprises an additional third outlet, Figure 7B shows an assembly applicable to a vapor circuit;
Figure 8 is a perspective view of a dishwasher comprising an assembly according to the present invention;
Figure 9 is a circuit block diagram of the electronic devices connected to a central control unit;
Figure 10 is an exploded view of a variant of the arm of Figure 1;
Figures 11A, 11B and 11C show some alternative embodiments of the assembly, wherein said rotary sprayer is fixedly supported by said arm, which is rotatably driven; in particular, Figure 11A shows a first embodiment wherein the rotatably driven rotary sprayer is symmetric relative to the axis of rotation, Figure 11B is a sectional side view of the assembly of a second embodiment, wherein the rotary sprayer is asymmetric, Figure 11C is a perspective view of the assembly of Figure 11B;
Figures 12A and 12B show an alternative embodiment of the alternate wash assembly; in particular, Figure 12A is a sectional view of a second embodiment of the alternate wash assembly, Figure 12B shows in detail the selector comprised in the alternate wash assembly of Figure 12A.

With reference to the above-mentioned figures, the wash assembly is applied to a washing and/or drying machine; said assembly comprises at least one arm 3, for supporting at least one rotary sprayer 5, and at least one alternate wash assembly 4, which is adapted to deviate and distribute fluid flows from an inlet 44, connected to a supply circuit, to one or more outlets 43a, 43b, connected to one or more hydraulic circuits.
Said assembly comprises an actuating device 2 enabled to control the deviation and distribution of the fluid flows of said at least one alternate wash assembly 4, as well as the movement of said at least one arm 3.
In the embodiment shown in Figures 1, 2, 3A, 7A, 7B, 8 and 10, rotary sprayer 5 is movably supported by said arm 3. Preferably, rotary sprayer 5 is rotatably supported by said arm 3.
In the embodiments shown in Figures 11A-11C, instead, said rotary sprayer 5 is fixedly supported by said arm 3. Preferably, said rotary sprayer 5 consists of said arm 3.
Said washing and/or drying machine is preferably a dishwasher 1 comprising an outer casing 10, a wash chamber 11, at least one rotary sprayer 5 for distributing wash fluid for washing crockery, as shown by way of example in Figure 8.
Inlet 44 of said alternate wash assembly 4 is connected to a wash pump (not shown), which takes water from a water collecting sump 6, located in the proximity of arm 3, thereby creating a closed supply circuit; said one or more outlets 43a, 43b are connected to as many hydraulic circuits, which are adapted to transport fluids, e.g. water, to the various areas of the wash chamber for distribution. Preferably, said alternate wash assembly comprises a first outlet 43a, which is connected to a hydraulic circuit adapted to supply an upper rotary sprayer (not shown); and a second outlet 43b, which is connected to a hydraulic circuit adapted to supply the lower rotary sprayer 5.
Essentially, said alternate wash assembly 4, shown by way of example in Figures 6A, 6B and 6C, comprises a chamber 41 in which a selector 42 is arranged, which is moved through said actuating device 2. Said selector 42 is adapted to selectively open and/or close one or more outlets 43a, 43b depending on which hydraulic circuit must be activated and/or deactivated.
The shape, dimensions and typology of selector 42 in use may vary, compared to the embodiment illustrated herein, depending on design specifications, while still falling within the protection scope of the present invention. For the purposes of the present invention, the operation of alternate wash assembly 4 will not be described in detail herein, since it is known to those skilled in the art.
In an alternative embodiment of alternate wash assembly 4, shown in Figure 6C, chamber 41 internally comprises at least one heating means 46, e.g. a resistor, adapted to selectively heat the fluid, e.g. water, that must be directed to the various hydraulic circuits connected to alternate wash assembly 4. The use of heating means 46 allows to eliminate the pressure switch normally included in prior-art dishwashers 1, along with the associated take-off on sump 6 and welding of sump 6.
Said at least one heating means 46 comprises safety devices 461, which are connected to a central control unit 8. Preferably, said safety devices 461 are electric/pneumatic and comprise at least one sensor 462 and one switch adapted to determine the temperature and/or the pressure of the fluid and to deactivate said at least one heating means 46 when a preset temperature is reached or if the pressure drops, e.g. inside chamber 41. In fact, temperature sensor 462 is monitored by said control unit 8, which, when it detects a temperature equal to or higher than a preset maximum temperature, will deactivate heating device 46 by opening the electric circuit.
If a pressure drop occurs due to lack of water or other faults, such as, for example, a malfunctioning wash pump, sensor 462 will either open the switch directly or send a signal, e.g. to control unit 8, for opening the switch and turning off heating means 46.
Preferably, said control unit 8 will open the switch, thereby opening the circuit of heating means 46, should any current dispersion occur which might be potentially dangerous for the user of dishwasher 1.
In addition, as shown in Figure 7A, said alternate wash assembly 4 may comprise a third outlet 43c adapted to be connected to a hydraulic circuit comprising a water recovery container (not shown in the drawings) or a drying device.
Figures 12A and 12B illustrate an alternative embodiment of the alternate wash assembly. In particular, Figure 12A shows an alternate wash assembly 4, which comprises a chamber 41 that can be run through by a pressurized fluid flow; a rotatable selector 42 fitted to a first shaft 221a through coupling portion 423 and adapted to rotate about a first axis of rotation "X", which is preferably vertical; an inlet 44 fluidically located upstream of chamber 41; and a pair of outlets 43a, 43b, fluidically located downstream of chamber 41. On the walls that define chamber 41 there is a substantially axial seat, which is fluidically located between chamber 41 and the first outlet 43a, and a substantially radial seat, which is fluidically located between chamber 41 and the second outlet 43b. Selector 42 can be placed into a first or a second operating conditions, in which conditions selector 42 clears or obstructs, respectively, the seat corresponding to the first outlet 43a, and obstructs or clears, respectively, the seat corresponding to the second outlet 43b.
With particular reference to Figure 12A, selector 42 preferably comprises an obstructing portion 420 with a projection 42a jutting out in a substantially axial direction, which is adapted to obstruct or clear the substantially radial seat, thereby obstructing or clearing the first outlet 43a, when selector 42 is in predetermined operating configurations.
In this embodiment, projection 42a is located in the peripheral part of obstructing portion 420, as clearly shown by way of example in Figure 12B.
Preferably, said projection 42a defines an arched wall supported by obstructing portion 420 and adapted to overlap the substantially radial seat when the obstructer is in a first operating condition.
In this embodiment, obstructing portion 420 has a substantially axial aperture 422, which is offset relative to the first axis of rotation "X", and which is adapted to clear the substantially axial seat when selector 42 is in the first operating condition, thereby allowing the fluid to flow towards the first outlet 43a. When, on the contrary, selector 42 is in the second operating condition, aperture 422 is no longer aligned with the substantially axial seat, so that a solid region of obstructing portion 420 abuts against and obstructs the substantially axial seat, thereby preventing the fluid from flowing towards the first outlet 43a.
Preferably, aperture 422 is located, on obstructing portion 420, in a position angularly delimited by projection 42a. In particular, aperture 422 is substantially comprised in circular sector "ϕ" defined by projection 42a on obstructing portion 420; in this regard, reference should be made for more clarity to the dashed-dotted lines drawn on Figure 12b.
By way of example, aperture 422 has a substantially circular cross-section.
In particular, said aperture 422 opens into the first outlet 43a, which in its turn has a cross-section substantially matching that of said aperture 422.
In this embodiment, obstructing portion 420 is substantially shaped like a plate, in particular like a disk, e.g. substantially circular.
Said actuating device 2 comprises an actuator 21, preferably a single motor, and at least one motion transmission mechanism 22, which is adapted to transmit motion from said actuator or motor 21 to both said at least one arm 3 and said at least one alternate wash assembly 4. Preferably, actuating device 2 is located outside wash chamber 11 of said washing machine 1 whereto said assembly has been applied. In fact, said actuating device 2 is preferably arranged underneath the bottom base of wash chamber 11, thus being protected against the action of water, and particularly not being in direct contact with either the wash water or the dirt residues resulting from the various wash steps, so that any corrosion or seizure of the motion transmission mechanisms 22 is prevented.
Said actuating device 2 is in its turn controlled by a central control unit 8 for the purpose of allowing said at least one arm 3 to be arranged in predetermined positions inside the wash chamber. As aforementioned, in the embodiment shown in Figures 1, 2, 3A, 7A, 7B, 8 and 10, said arm 3 is surmounted by at least one movably, e.g. rotatably, supported rotary sprayer 5. In said embodiment, said central control unit 8 allows moving said at least one arm 3 in a manner such that rotary sprayer 5 will stay in predetermined positions within the wash chamber for predetermined time periods. In the embodiment shown in Figures 11A, 11B and 11C, instead, said rotary sprayer 5 preferably consists of said arm 3. In this embodiment, said central control unit 8 allows moving said arm 3 in a manner such that it will stay in predetermined positions within the wash chamber for predetermined time periods, and/or such that it can turn at a predetermined speed, which may be faster and/or slower than the known revolution speed of a prior-art rotary sprayer. The solution described in Figures 11A-11C allows adjusting the revolution speed of arm 3, and hence of rotary sprayer 5, independently of the pressure of the wash fluid.
In particular, as shown in Figure 9, central control unit 8 is susceptible of being connected to said motor 21.
Preferably, said central control unit 8 is adapted to execute a wash program of the same dishwasher 1, which specifies the positions and the stop times of rotary arm 3 within wash chamber 11. Said control unit 8 may be connected to said memory unit 81, which stores at least one wash program. Said control unit 8 may possibly comprise said memory unit 81.
Preferably, at the beginning of each wash step arm 3 is always positioned in such a way that rotary sprayer 5 is in a predetermined sector of the chamber 11. At the end of each wash cycle, arm 3 may possibly stop in a predetermined position prior to the beginning of the next wash cycle.
Central control unit 8 is adapted to activate other devices normally included in dishwasher 1 and to monitor a plurality of sensors which are useful for controlling the same dishwasher. Such devices and sensors will not be described in detail herein, since they are known to those skilled in the art.
In the embodiment shown in Figures 1, 2, 3A, 7A, 7B, 8 and 10, arm 3 is rotatably supported around a fixed axis, preferably a second axis of rotation "Z", preferably vertical, located in the proximity of the centre of the base of wash chamber 11. In particular, said arm 3 is located in the proximity of sump 6, comprised in wash chamber 11. The revolution speed of rotary arm 3 may be a multiple or submultiple of the revolution speed of selector 42 of the alternate wash assembly.
In a non-limiting first embodiment, as shown by way of example in Figures 3A and 3B, said motion transmission mechanism 22 comprises said first shaft 221a fitted on one end to said selector 42 of alternate assembly 4 and on the opposite end to the shaft of motor 21; a second shaft 221b is fitted on one end to a joining element 30 of arm 3 and on the other end to a pinion 222b, which meshes with a crown wheel 222a mounted to said first shaft 221a. The ratio between said crown wheel 222a and said pinion 222b is such that the revolution speed of the first shaft 221a is a multiple of the revolution speed of said second shaft 221b.
In a second embodiment, said second shaft 221b is fitted on one end to a joining element 30 of arm 3 and on the opposite end to the shaft of motor 21; the first shaft 221a is fitted on one end to said selector 42 of alternate assembly 4 and on the opposite end to a pinion 222b, which meshes with a crown wheel 222a mounted to said second shaft 221b.
In a third embodiment, shown in Figures 11B and 12A, said first shaft 22a and said second shaft 221b are arranged parallel to each other, respectively along a first axis of rotation "X" and a second axis of rotation "Z", and are located at a distance from the shaft of motor 21, which is arranged along a third axis of rotation "Y", parallel to said first and second axes (X, Z). Both said first shaft 221a and said second shaft 221b are rotated by a respective suitable gear train.
Said motor 21 is an electric motor, e.g. a step motor, as normally used for driving selector 42 of alternate wash assembly 4. Preferably, the maximum torque of said motor 21 is limited in order to avoid any damage to actuating device 2 which might be due, for example, to an improperly positioned piece of cutlery stopping the rotation of the arm.
In a preferred embodiment, shown by way of example in Figure 9, said actuating device 2 comprises at least one sensor 24 adapted to detect the position of arm 3 and/or of selector 42. Preferably, said at least one sensor 24 is, for example, an encoder, mounted to said second shaft 221b and adapted to determine the direction of rotation of arm 3 and the absolute position thereof within the wash chamber, with a predetermined uncertainty, as a function of the rotation of shaft 221b. Said at least one sensor 24 may be a position sensor of any type, such as, for example, capacitive, resistive, inductive, etc.
Said at least one sensor 24 is susceptible of being connected to said control unit 8, for the purpose of determining the position of arm 3, so that rotary sprayer 5 can be positioned as required within the wash chamber. In fact, said sensor 24 allows rotary sprayer 5 to be positioned in a desired area of wash chamber 11 through an appropriate movement of arm 3. Control unit 8, depending on the data received from said sensor 24, can operate motor 21 in a manner such as to place rotary sprayer 5 into the desired position by rotating said arm 3.
Said arm 3 is connected to the hydraulic circuit intended for lower rotary sprayer 5; in particular, arm 3 is mounted through fastening means 62 to said second outlet 43b, which is located in a housing within sump 6.
In addition to supporting associated rotary sprayer 5, arm 3 also acts as a duct to supply water to rotary sprayer 5 from the second outlet 43b of alternate assembly 4, to which it is connected.
In particular, said arm 3 is mounted on rolling bearings that allow arm 3 to rotate, e.g. by 360°, about said second axis of rotation "Z".
As aforementioned, arm 3 is fitted to said second shaft 221b, but comprises an internal duct 31 allowing water to flow from alternate wash assembly 4 to rotary sprayer 5.
As shown in the drawings, said arm 3 is preferably an asymmetric arm, since it comprises a coupling portion 32 in the proximity of one end of said arm 3, and a peripheral portion 33 at the opposite end of said arm 3, where said rotary sprayer 5 is mounted.
Said coupling portion 32 comprises said joining element 30 fitted to said second shaft 221b, so that the axis of rotation of arm 3 corresponds to the axis of rotation of the second shaft 221b. Said coupling portion 32 also defines a first portion of duct 31, thereby allowing fluids to flow from said alternate wash assembly to rotary sprayer 5. Preferably, said arm 3 is made of plastic material, comprising an upper portion 3a and a lower portion 3b that can be removably combined together, as shown in Figures 4A and 5A.
Preferably, said joining element 30 comprises at least one torque limiting means 23 adapted to disengage arm 3, preferably arranged in said coupling portion 32, which is connected to said joining element 30.
In a first embodiment, shown by way of example in Figures 4A, 4B and 4C, torque limiting means 23 comprises a selective abutment element 231 appropriately associated with said joining element 30, which is adapted to abut against the inner walls of internal duct 31 in coupling portion 32; an elastic means 232, e.g. a spring, and a top element 233.
When predetermined torque value of the second shaft 221b is exceeded, as a function of the elastic constant of elastic means 232, selective abutment element 231 will slip on joining element 30, thereby preventing motion from being transmitted to arm 3 by shaft 221b.
The principle of operation of torque limiting means 23 of the first embodiment is such that, following the release of arm 3 a new balance point will be reached after a rotation by 360° of shaft 221b, where arm 3 will be engaged again so that it can rotate about said second axis of rotation "Z". Said torque limiting means 23, therefore, has only one balance point.
In a second embodiment, shown in Figures 5A, 5B and 5C, joining element 30 comprises an abutment portion 234 made of ferrous or ferromagnetic material, which is adapted to abut against a magnetic element 235, so that interference therebetween is generated, thereby allowing motion to be transmitted to arm 3 by shaft 221b. When a predetermined torque value of second shaft 221b is exceeded, the magnetic force between abutment portion 234 and interference element 235 becomes smaller than the force applied to arm 3, so that abutment element 234 will move away from magnetic element 235, thereby preventing motion from being transmitted to said arm 3.
Following the release of arm 3, shaft 221b must rotate by approximately 360° in order to engage and drive arm 3 again. This torque limiting means 23 has one balance point when abutment element 234 is in the proximity of magnetic element 235, so that the magnetic force will tend to hold them abutted against each other.
Preferably, said rotary sprayer 5 is a symmetric satellite sprayer rotating about a respective axis of rotation "R", which is parallel to the axis of rotation of arm 3. Rotary sprayer 5 preferably has a tapered shape, its dimensions, e.g. in the longitudinal direction, being smaller than the standard dimensions used for conventional lower rotary sprayers. In particular, the longitudinal extension of rotary sprayer 5, which is secured to arm 3 in accordance with the present invention, is at most equal to half the smallest dimension of the base of wash chamber 11.
In particular, said rotary sprayer 5 is mounted onto a suitable through housing 34 comprised in the peripheral portion 33 of arm 3. Said housing 34 is adapted to allow rotary sprayer 5 to rotate freely, as well as to allow the wash fluid to flow towards said rotary sprayer 5.
The same rotary sprayer 5 comprises an engagement mouth 52, which is adapted to fit into said housing 34 to allow the fluid to flow into rotary sprayer 5 and come out through a plurality of nozzles 51 in order to hit the crockery arranged in a lower rack positioned inside wash chamber 11 of dishwasher 1.
Said nozzles 51 are appropriately arranged on said rotary sprayer 5, preferably on the upper portion of said rotary sprayer 5, and have predetermines sizes. Preferably, the sizes of said nozzles 51 are smaller than the average sizes of the nozzles comprised in the lower rotary sprayers currently available on the market.
Said engagement mouth 52 comprises removable locking means 53, e.g. interference means, which are adapted to retain said rotary sprayer 5 in order to prevent it from accidentally detaching from said arm 3.
Internal duct 31 of arm 3, under said suitable housing 34, comprises a protuberance 311 which is appropriately shaped to avoid any fluid flow turbulences in duct 31 and to direct the same fluid into rotary sprayer 5.
In an alternative embodiment, shown in Figure 10, arm 3 according to the present invention comprises at least one nozzle 51 to increase the wash power, preferably located in upper portion 3a of the same arm 3.
In a preferred embodiment, shown in Figure 7B, the assembly according to the present invention can be applied to a vapor circuit or to a hydraulic circuit for water at a higher temperature than the fluid coming from the alternate wash assembly 4. In particular, internal duct 31 of arm 3 can be used for conducting water vapor towards the same rotary sprayer 5 when the latter is positioned under crockery, such as pots, for improving the washing or the drying action.
The use of an asymmetric arm and a smaller rotary sprayer makes available more room in wash tub 11.
The use of a smaller rotary sprayer 5, which can be moved to different sections over the base of wash chamber 11, allows, as aforementioned, to reduce the dimensions of sprayer nozzles 51.
Comparing the dimensions of rotary sprayer 5 with those of the lower rotary sprayers commonly used in prior-art dishwashers, the longitudinal extension of rotary sprayer 5 according to the present invention is half the longitudinal extension of current lower rotary sprayers.
The movement of arm 3 about said second axis of rotation "Z" and the small dimensions of rotary sprayer 5 allow to wash only a portion of the rack, e.g. only one fourth of the rack at a time, thus reducing the water consumption also because of the smaller number of nozzles 51. By way of example, for a wash chamber 11 having a 50cm side, the longitudinal dimension of arm 3 is smaller than 12.5 cm, while the rotary sprayer has a longitudinal extension of less than 25 cm. The number of nozzles 51 of lower rotary sprayer 5 is almost halved.
The possibility of moving arm 3, and hence of placing the rotary sprayer into desired positions for washing a particular sector of lower rack 12, improves the washing of the crockery arranged in the same rack 12 because the crockery is better sprinkled with wash fluid. Furthermore, the controlled movement of arm 3 allows arm 3 to be positioned in a manner such that the fluid jets from nozzles 51 of arm 3 and/or of rotary sprayer 5 are at least partly directed towards a detergent dispenser 14 comprised in dishwasher 1, into which the user has previously poured a predetermined quantity of detergent. The possibility of intentionally directing the fluid jets towards said detergent dispenser allows dissolving the detergent into the fluid as a function of the wash step to be carried out.
The dimensions of rotary sprayer 5 and the rotation of arm 3 about said second vertical axis "Z" allow to improve the washing in the central area of wash chamber 11 of dishwasher 1, by improving the trajectories of the fluid jets coming from the rotary sprayer.
Furthermore, the smaller number of nozzles 51 and the possibility of changing the position of rotary sprayer 5 within wash chamber 11 ensure a lower consumption of liquid, in particular water, used for washing the crockery. The smaller quantity of wash water required allows to reduce the capacity of the wash pump and the power of the associated motor, resulting in lower production costs. The possibility of positioning the rotary sprayer into particular sectors of wash chamber 11 allows to improve the wash performance, in that it is possible to change the stop times of rotary sprayer 5 in the various positions depending on the wash program in execution.
The assembly according to the present invention allows to use just a single device, in particular a single motor 21, for carrying out two functions which are normally carried out in an independent and uncorrelated manner. The solution according to the present invention, therefore, makes for lower production costs.

REFERENCE NUMERALS:

1 Dishwasher
10 Outer casing
11 Wash chamber
12 Rack
14 Detergent dispenser
2 Actuating device
21 Motor
22 Motion transmission mechanism
221a/b First and second shafts
222a Crown wheel
222b Pinion
23 Torque limiting means
231 Selective abutment element
232 Elastic element
233 Top element
234 Abutment portion
235 Magnetic element
24 Sensor
3 Arm
3a/b Upper and lower portions
30 Joining element
31 Internal duct
311 Protuberance
32 Coupling portion
33 Peripheral portion
34 Housing
4 Alternate wash assembly
41 Chamber
42 Selector
42A Projection
420 Obstructing portion
422 Aperture
423 Coupling portion
43a/b First and second outlets
43c Third outlet
44 Inlet
46 Heating means
461 Safety device
462 Temperature sensor
5 Rotary sprayer
51 Nozzles
52 Engagement mouth
53 Locking means
6 Sump
62 Fastening means
8 Central control unit
81 Memory unit
"X" First axis of rotation
"Z" Second axis of rotation
"Y" Third axis of rotation
"R" Axis of rotation of the rotary sprayer.

Claims

Wash assembly for a washing and/or drying machine; said assembly comprising:
- at least one arm (3), for supporting at least one rotary sprayer (5), and

- at least one alternate wash assembly (4), for diverting and distributing fluid flows from an inlet (44), connected to a supply circuit, to one or more outlets (43a, 43b), connected to one or more hydraulic circuits;
characterized in that it comprises an actuating device (2) enabled to control the deviation and/or distribution of the fluid flows of said at least one alternate wash assembly (4), as well as the movement of said at least one arm (3).
Assembly according to claim 1, wherein said actuating device comprises:
- a single motor (21), and

- at least one motion transmission mechanism (22) for transmitting motion from said motor (21) to both said at least one arm (3) and said at least one alternate wash assembly (4).
Assembly according to claim 1, wherein said actuating device (2) is external to the wash chamber of a washing machine whereto said assembly has been applied.
Assembly according to claim 1, wherein said actuating device comprises at least one sensor (24) adapted to determine the direction of rotation of arm (3) and the absolute position of said at least one arm (3) within the wash chamber (11) of a washing machine (1) whereto said device has been applied, allowing said rotary sprayer (5) to be positioned into a desired area of the wash chamber (11).
Assembly according to claim 1 or 4, wherein said actuating device (2) is in its turn controlled by a central control unit (8) for the purpose of allowing said at least one arm (3) to be positioned in a manner such that the rotary sprayer (5) will stay in predetermined positions inside the wash chamber for predetermined time periods.
Assembly according to claim 2, wherein said at least one motion transmission mechanism (22) comprises torque limiting means (23) for disengaging the arm (3).
Assembly according to claim 5 or 6, wherein said arm (3) is a rotary arm.
Assembly according to claim 7, wherein said actuating device (2) is in its turn controlled by a central control unit (8) for the purpose of allowing the positioning of said at least one arm (3).
Assembly according to claim 1, wherein said arm (3) comprises at least one nozzle (51) to increase the wash power.
Assembly according to claim 1, wherein said rotary sprayer (5) is rotatably supported by said arm (3).
Dishwasher (1) comprising an outer casing (10), a wash chamber (11), at least one rotary sprayer (5) for distributing wash fluid for washing crockery, and at least one assembly according to claim 1.
Dishwasher according to claim 11, wherein the arm (3) is rotatably supported around a fixed axis located in the proximity of the centre of the base of the wash chamber (11).
Dishwasher according to claim 11, which comprises a central control unit (8) adapted to execute a wash program of the same dishwasher (1) that specifies the positions and stop times of the rotary arm (2) inside the wash chamber (11).
Dishwasher according to claim 11, wherein the arm (3) can be positioned in a manner such that the fluid jets from a plurality of nozzles (51) of the arm (3) and/or of the rotary sprayer (5) are at least partly directed towards a detergent dispenser (14) comprised in the dishwasher (1).