EP1882435A1

EP1882435A1 - Revolving sprinkling assembly

Info

Publication number: EP1882435A1
Application number: EP06117747A
Authority: EP
Inventors: Luigi Salerno
Original assignee: Electrolux Home Products Corp NV
Current assignee: Electrolux Home Products Corp NV
Priority date: 2006-07-24
Filing date: 2006-07-24
Publication date: 2008-01-30

Abstract

Revolving sprinkling assembly for a dishwasher comprising:
- at least a sprinkler (2) provided with at least one propulsion nozzle (3) for causing the sprinkler (2) to rotate about a first axis of rotation (4),
- a movable arm (5) supporting the rotating sprinkler (2) and mounted rotatably about a second axis of rotation (6),
- driving means for moving the movable arm (5) so as to cause the first axis of rotation (4) of the sprinkler (2) to rotate about the second axis of rotation (6),
the driving means comprise a mobile gear wheel (7) connected with the sprinkler (2) for rotation in unison therewith about the first axis of rotation (4), a stationary gear wheel (8) coaxially arranged relative to the second axis of rotation (6), the mobile gear wheel (7) meshing with the stationary gear wheel (8) so that the propulsion nozzle (3) causes the mobile gear wheel (7) to roll along the stationary gear wheel (8), thereby driving the movable arm (5) into rotation about the second axis of rotation (6).

Description

The present invention relates to a revolving sprinkling assembly for dishwashers.
Revolving sprinklers of the kind as generally used in prior-art machines essentially consist of a single horizontal sprinkler rotatably mounted on a vertical-axis central shaft and provided with at least one propulsion nozzle at one end, as well as with other nozzles arranged along said sprinkler to sprinkle the dishes arranged on the dishwasher rack. Since the axis of rotation of the sprinkler is fixed, the resulting trajectories described by the nozzles consist of circumferences centered on said axis. This practically means that sprinkling assemblies of this kind constantly sprinkle the sole surfaces of the dishes, which lie along said circular paths, thereby limiting the washing effectiveness.
A solution to the above-noted drawbacks is proposed in US 5,464,482 in that it discloses a sprinkling assembly that includes a primary sprinkler having at least one secondary sprinkler rotatably mounted to one of its ends. During the rotation of the primary wash arm within a substantially square chamber, the secondary wash arm is rotated so as to extend into the corners of the chamber, so as to create a generally square spray pattern therein.
However, the drive mechanism used to generate the movement of the secondary sprinkler is particularly complicated. As a result, installing the sprinkling assembly inside the washing chamber turns out as being quite time-consuming and generally demanding a process, which may require up to several working hours. In addition, the considerable number of component parts entering the construction of this sprinkling assembly, further to increasing the manufacturing costs thereof, make the same assembly more likely to undergo malfunctioning problems and mechanical failures.
Furthermore, since there are two sprinklers fluidly connected with each other, which thereby give rise to a considerable pressure drop in the water supply line, the need arises for the sprinkling assembly to be supplied with water at quite high a pressure in view of ensuring that the water jets are issuing from the nozzles under an adequate force for a satisfactory washing effect.
In another attempt to solve the above-noted drawbacks, EP 1 090 579 discloses a revolving sprinkling assembly for dishwashers that, further to a sprinkler, includes 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 mobile support means consists of a rotating shaft provided at the top with a transverse extension, at the free end of which there is rotatably mounted the sprinkler, so that the axis of rotation of the latter is eccentric relative to axis of rotation of the shaft. The shifting of the mobile support means is achieved through a toothed rim engaging a gear that is driven into rotation by an electric actuator. The rotating shaft is alternately rotated by 180° in one direction and by 180° in the opposite direction by said electric actuator to perform a non-complete epicyclical motion.
However, even such solution has a drawback in that it turns out as being particularly complicated, requiring a plurality of gear members and, above all, an electric actuator to drive the whole revolving sprinkling assembly into the rotary movement thereof. The use of such electric actuator causes the overall energy usage required to complete a washing cycle to increase to a significant extent, thereby making such solution scarcely attractive even from a purely economic point of view.
It is therefore a main object of the present invention to provide a revolving sprinkling assembly for dishwashers, which is effective in doing away with the above-noted drawback of the cited prior art.
According to the present invention, these aims, along with further ones that will become apparent from the following disclosure, are reached in a sprinkling assembly for dishwashing machines that incorporates the features as defined and recited in the claims appended hereto.
Features and advantages of the present invention will anyway be more readily understood from the description that is given below by way of nonlimiting example with reference to the accompanying drawings, in which:

Figure 1 is a side elevational view of a revolving sprinkling assembly according to the present invention;
Figure 2 is a side elevational, cross-sectional view of the revolving sprinkling assembly shown in Figure 1;
Figure 3 is a top plan view illustrating the epicyclical motion of the revolving sprinkling assembly according to the present invention;

With reference to the above-cited Figures, the revolving sprinkling assembly for a dishwasher, as generally indicated with the reference numeral 1, comprises at least one sprinkler 2 provided with at least one propulsion nozzle 3 for causing the sprinkler to rotate about a first axis of rotation 4, a movable arm 5 supporting said rotating sprinkler 2 and mounted to rotate about a second axis of rotation 6, driving means for moving said movable arm 5 so as to cause the first axis of rotation 4 of the sprinkler 2 to rotate around the second axis of rotation 6.
The driving means comprise a mobile gear wheel 7 connected with the sprinkler 2 for rotation in unison therewith about the first axis of rotation 4, a stationary gear wheel 8 coaxially arranged with respect to the second axis of rotation 6, wherein the mobile gear wheel 7 meshes with the stationary gear wheel 8 so that said propulsion nozzle 3 causes the mobile gear wheel 7 to roll along the stationary gear wheel 8, thereby driving the movable arm 5 into rotation around the second axis of rotation 6.
The sprinkling assembly shown in the Figures is provided for arrangement within the washing chamber of a dishwashing machine. In particular, it is arranged in the lower portion of the washing chamber, in proximity of the collecting sump, so that the sprinkler 2 forms the lower sprinkler of the dishwashing machine.
The sprinkler 2 is rotatably mounted centrally on the movable arm 5 to rotate in a horizontal plane about the first axis of rotation 4. The sprinkler includes a plurality of spray holes, or nozzles, through which washing liquor is sprayed.
The rotation of the sprinkler 2 is achieved by means of at least one propulsion nozzle 3 that is provided at an end portion of the sprinkler 2 and is so inclined as to eject a water jet with a horizontal component. The liquor being so ejected from the propulsion nozzle imparts a rotational movement to the sprinkler, thereby causing the latter to rotate about the first axis of rotation 4. The other washing nozzles 9 eject vertical sprays to sprinkle the dishes. The water being supplied under pressure by the washing pump reaches the sprinkler 2 through the movable arm 5.
The movable arm 5 forms a water delivery conduit, which is adapted to convey the washing liquor up to the sprinkler 2.
The movable arm 5 supports the rotating sprinkler 2 at an end portion thereof, and is mounted rotatably about the second axis of rotation 6 so as to be able to turn therearound.
The sprinkler 2 comprises a central hub 10, by means of which it is rotatably associated to an end portion of the movable arm 5. Bearings in the form of low-friction bushings 11 are provided between the end portion of the movable arm 5 and the hub 10 of the sprinkler so as to ensure smooth rotation of the latter.
The mobile gear wheel 7 is firmly joined to the hub 10 so as to rotate jointly with the sprinkler, in unison therewith, i.e. at the same angular speed, about the first axis of rotation 4 in a horizontal plane extending parallel to the plane in which the sprinkler 2 rotates.
In an advantageous manner, the mobile gear wheel 7 may be provided integrally with the hub 10 of the sprinkler 2, i.e. as a unitary-piece construction therewith. Alternatively, it may however be provided as a separate piece for subsequent assembly on to the hub 10.
The movable arm 5 is mounted rotatably on an upstanding support member or pivot-like post 12, which is provided within the washing chamber in a centered arrangement with the second axis of rotation 6, i.e. placed so as to have its own axis coinciding with the second axis of rotation 6.
The movable arm 5 comprises a cylindrical head that is press-fitted, or anyway fitted, rotatably on said upstanding support member 12, so that the movable arm itself is free to rotate about the second axis of rotation 6.
The upstanding support member 12 is fluidly connected with the movable arm 5 and the washing pump to deliver the washing liquor to the sprinkler 2. 0-ring seals 13 are provided to ensure the required watertightness between the upstanding support member 12 and the movable arm 5, while low-friction bushing-type bearings 14, which may for instance be made of a material such as Teflon^®, are provided to rotatably couple the movable arm 5 with the mounting support member 12 thereof.
Preferably, the second axis of rotation 6 coincides with the central axis of symmetry of the washing chamber of the machine.
The stationary gear wheel 8 is secured to an end portion of the upstanding support member 12 so as to be stationary relative to the washing chamber. The same stationary gear wheel 8 is arranged horizontally so that the central axis thereof is coaxial with the second axis of rotation 6.
In practice, the circular toothed profile of the stationary gear wheel 8 extends annularly relative to a centre that is situated along the second axis of rotation 6.
Furthermore, the stationary gear wheel 8 integrally defines a square-section attachment stem 15 that extends along the central axis of the stationary gear wheel 8 perpendicularly thereto. This attachment stem 15 is adapted to engage a corresponding coupling hole provided in the end portion of the upstanding support member 12, so as to keep the stationary gear wheel 8 firmly in position. In addition, the stationary gear wheel 8 comprises a plurality of projections adapted to cooperate with corresponding recesses provided on the end portion of the upstanding support member 12 to facilitate correct positioning of the stationary gear wheel 8.
The stationary gear wheel 8, the movable arm 5 and the sprinkler 2 are arranged so that the mobile gear wheel 7 is able to directly engage the stationary gear wheel 8, in that the circular toothed rim of the mobile gear wheel 7 directly meshes with the circular toothed rim of the stationary gear wheel 8.
The mobile gear wheel 7, which is provided to rotate jointly with the sprinkler 2, is adapted to roll along the circular toothed rim of the stationary gear wheel 8 in a horizontal plane. Via the central hub 10 of the sprinkler 2, the mobile gear wheel 7 is therefore able to transfer the angular momentum to the movable arm 5, thereby driving it rotatably about the second axis of rotation 6. In turn, the movable arm 5 carries the sprinkler 2 rotatably about the second axis of rotation 6.
Owing to mobile gear wheel 7 and the stationary gear wheel 8 being so intermeshed, the rotation of the mobile gear wheel 7 about the first axis of rotation 4, as brought about by the propulsion nozzle 3, imparts a rotational motion to the movable arm 5 about the second axis of rotation 6. As an ultimate result, the first axis of rotation 4 of the sprinkler 2 rotates about the second axis of rotation 6, i.e. the central axis of the washing chamber, and the sprinkler 2 therefore performs an epicyclical movement.
The direct coupling of the mobile gear wheel 7 with the stationary gear wheel 8 enables the sprinkler 2 and the movable arm 5 to perform a complete (i.e. by 360°) and continuous rotary movement in the same direction of rotation about the first axis of rotation 4 and the second axis of rotation 6, respectively, as this is best shown in Figure 3, wherein such rotation may of course take place in the clockwise or anti-clockwise direction as needed.
The sprinkler 2 is driven into the epicyclical rotary motion thereof solely by the effect of the torque generated by the liquor under pressure ejected from the propulsion nozzle. The epicyclical motion of the sprinkler 2 therefore depends on liquor being supplied to the sprinkling assembly.
Conclusively, it can therefore be stated that the revolving sprinkling assembly according to the present invention describes a movement that ensures an effective spray pattern of the washing liquor being sprinkled onto the dishes, while such movement is obtained in an extremely simple manner, thereby doing away with the serious drawback shared by prior-art machines.

Claims

Revolving sprinkling assembly for a dishwasher comprising:
- at least a sprinkler (2) provided with at least one propulsion nozzle (3) for causing the sprinkler (2) to rotate about a first axis of rotation (4),

- a movable arm (5) supporting said rotating sprinkler (2) and mounted rotatably about a second axis of rotation (6),

- driving means for moving said movable arm (5) so as to cause the first axis of rotation (4) of the sprinkler (2) to rotate about the second axis of rotation (6),
characterized in that said driving means comprise a mobile gear wheel (7) connected with the sprinkler (2) for rotation in unison therewith about the first axis of rotation (4), a stationary gear wheel (8) coaxially arranged relative to the second axis of rotation (6), the mobile gear wheel (7) meshing with the stationary gear wheel (8) so that said propulsion nozzle (3) causes the mobile gear wheel (7) to roll along the stationary gear wheel (8), thereby driving the movable arm (5) into rotation about the second axis of rotation (6).
Revolving sprinkling assembly according to claim 1, wherein the sprinkler (2) comprises a central hub (10), by means of which it is rotatably associated to an end portion of the movable arm (5).
Revolving sprinkling assembly according to claim 2, wherein the mobile gear wheel (7) is firmly associated to the hub (10) to rotate jointly with the sprinkler (2), at the same angular speed thereof, about the first axis of rotation (4) in a horizontal plane extending parallel to a plane in which the sprinkler (2) rotates.
Revolving sprinkling assembly according to claim 3, wherein said mobile gear wheel (7) is integrally provided in a unitary-piece construction with said central hub (10) of the sprinkler (2).
Revolving sprinkling assembly according to claim 1, wherein said movable arm (5) is rotatably mounted on an upstanding support member (12) centered in on said second axis of rotation (6), i.e. arranged with its own axis coinciding with said second axis of rotation (6).
Revolving sprinkling assembly according to claim 5, wherein said stationary gear wheel (8) is linked to an end portion of said upstanding support member (12).
Revolving sprinkling assembly according to any of the preceding claims, wherein the stationary gear wheel (8) is arranged horizontally so that the central axis thereof lies in a coaxial arrangement with the second axis of rotation (6).
Revolving sprinkling according to any of the preceding claims, wherein said propulsion nozzle (3), by the effect of said mobile gear wheel (7) and said stationary gear wheel (8) being so intermeshed, is adapted to impart a rotary motion to the movable arm (5) about the second axis of rotation (6).
Revolving sprinkling assembly according to any of the preceding claims, wherein the sprinkler (2) and the movable arm (5) are adapted to continuously rotate about the first axis of rotation (4) and about the second axis of rotation (6), respectively, in the same direction of rotation.
Dishwasher, characterized in that it comprises a revolving sprinkling assembly according to any of the preceding claims.