Wash arm arrangement for a dishwasher

Description

[0001] This invention relates to a wash arm arrangement for a dishwasher comprising a treatment chamber having one or several freely rotating support arms that are provided with one or several freely rotating spray arms through which liquid is distributed to the dish in the treatment chamber.

[0002] Conventional dishwashers of the household type are usually provided with an upper and a lower rotating wash arm provided with several spray nozzles distributing the cleaning liquid to the dish which is placed in the treatment chamber. At least one of the nozzles is arranged such that a reaction force is created causing the wash arm to rotate. These spray systems have the disadvantage that the each spray of the rotating nozzle hits the same circle every revolution.

[0003] There also are previously known dishwasher arrangements, see for instance US 5477874 or DE 4416655, operating with one or several rotating support arms on which a spray arm is rotating. The support arm as well as the spray arm are provided with several spray nozzles some of which are directed such that a horizontal force component is created directly on the support arm as well as the spray arm causing the two arms to rotate. This means that a part of the flow is used to rotate the support arm.

[0004] Another type of wash arm arrangement is shown in EP 727177. According to this arrangement there is a reciprocating support arm provided with a rotating spray arm at each end. The support arm achieves its reciprocating motion by means of nozzles provided at the spray arms and the spray arms are mutually connected by means of a gear mechanism in order to synchronize the motion of the spray arms such that a balanced uniform motion is created. This is however a complicated and rather expensive solution.

[0005] The purpose of this invention is, contrary to traditional wash arm systems, to use a dishwasher spraying system that is distributing the liquid in a non uniform way by driving the support arm in incremental steps. This means that a more effective and faster washing can be achieved resulting in less water and energy consumption. It also means a simple and cheap wash arm arrangement using a freely rotating support arm that is provided with a freely rotating spray arm for driving the support arm. The arrangement is such that all the liquid used in the washing procedure is arranged to flow through the spray nozzle and there is consequently no loss of flow in order to drive the support arm separately.

[0006] An embodiment of the invention will now be described with reference to the accompanying drawing on which Fig. 1 shows a perspective view of a dishwasher according to the invention, Fig. 2 is a schematic plan view of the wash arm arrangement according to the invention, Fig. 3 is a section on the line III-III in Fig 2 whereas Fig 4 shows the driving forces of the spray arm and the support arm.

[0007] Fig. 1 shows a dishwasher 10 having a treatments chamber 11 in which dish is inserted on a lower and an upper basket 12 and 13. The treatment chamber is provided with a door 14 and has a wash arm arrangement 15 placed below the lower basket 12 as well as below the upper basket 13. The dishwasher is in a conventional manner provided with a circulation pump that distributes a cleaning liquid from a collecting container at the bottom of the treatment chamber to the wash arm arrangement from which it is sprayed towards the dish which is placed on the baskets.

[0008] The wash arm arrangement 15 comprises a support arm 16 that is rotating freely on a feeding duct 17 to which the cleaning liquid is supplied by said circulation pump. The support arm has a closed structure with the exception of an inlet opening 18 placed at the feeding duct 17 and an outlet sleeve 19 at the outer end of the support arm. The outlet sleeve 19 supports a spray arm 20 that rotates freely on the sleeve. The spray arm is provided with several nozzles 21 that direct the flow mainly vertically towards the dish. The spray arm is further provided with an additional nozzle 22 at one of its ends through which a cleaning liquid jet is directed obliquely upwards or sideways.

[0009] The arrangement operates in the following way. Cleaning liquid is distributed from the feeding duct 17 via the opening 18 into the support arm 16 and further through the outlet sleeve 19 and the nozzles 21 via the spray arm 20. Simultaneously liquid is flowing out through the nozzle 22 mainly perpendicular to the length direction of the spray arm 20 causing a horizontal driving force F on the spray arm. This force F creates a momentum about the sleeve 19 such that the spray arm 20 starts to rotate. The rotation of the spray arm 20 generates a friction momentum C at the sleeve 19 that forces the support arm 16 to rotate. At the same time the force F is transmitted to the support arm 16 through the sleeve 19 by its component F1 parallel to the support arm 16 and F2 perpendicular to it. Component F2 creates a momentum around the feeding duct 17 which is added up to the friction momentum C at the sleeve 19 and contributes to the rotation of the support arm 16. Eventually the support arm 16 rotates with periodical angular velocity originated by a constant component C (friction given by satellite rotation) added up to a periodical one given by the component F2 of the force F. By choosing suitable friction at the feeding duct 17 and at the sleeve 19 the support arm 16 is rotated in incremental steps. Due to that the increment steps are not fixed the position of the sprays will vary continuously thereby minimizing the risk for areas not being washed. Thus, the system creates a heavy flow directed at the items above the wash arm and this flow transports the dirt away in an efficient manner.

Claims

1. Dishwasher comprising a treatment chamber (11) and a wash arm arrangement having one or several freely rotating support arms (16) that are provided with one or several freely rotating spray arms (20) for driving the support arm (16), through which spray arm (20) liquid is distributed to the dish in the treatment chamber,
characterized in that
the liquid is distributed in a non uniform way by driving the support arm (16) in incremental steps,
whereby the spray arm (20) is provided with at least one nozzle (22) arranged such that one horizontal reaction force component (F) from the jet flowing out from the nozzle creates a moment (C) for the spray arm (20) about its rotation centre as well as a moment (M) for the support arm (16) about its rotation centre, and
whereby a suitable friction at the supporting means (17, 19) of the spray arm (20) and of the support arm (16) is chosen to achieve the rotation of the support arm (16) in incremental steps.

2. Dishwasher according to claim 1, characterized in that all the movement of the support arm is created as reaction forces and/or moments from the spray out of the spray arm.

3. Dishwasher according to claim 1 or 2, characterized in that all the liquid which is fed to the support arm (16) is arranged to flow out into the treatment chamber through the spray arm (20).

4. Dishwasher according to any of claims 1-3, characterized in that the support arm (16) is a closed structure having one liquid inlet (18) and one liquid outlet (19).

5. Dishwasher according to any of claims 1-4, characterized in that the spray arm (20) is provided with at least one nozzle (22) arranged such that one horizontal reaction force component (F) from the jet flowing out from the nozzle creates a moment (C) for the spray arm (20) about its rotation centre as well as a moment (M) for the support arm (16) about its rotation centre.

6. Dishwasher according to any of claims 1-5, characterized in that the dishwasher is provided with at least one liquid feeding duct (17) on which the support arm is arranged to rotate.

7. Dishwasher according to claim 6, characterized in that said support arm (16) is comprising an outlet sleeve (19) that supports a spray arm (20) freely rotating on the sleeve (19), and that a suitable friction at the feeding duct (17) and at the sleeve (19) is chosen to achieve the rotation of the support arm (16) in incremental steps.

8. Dishwasher according to claim 7, characterized in that the support arm (16) is a closed structure having one liquid inlet (18) placed at the feeding duct (17) and one liquid outlet which is said outlet sleeve (19).

Ansprüche

1. Geschirrspülmaschine, umfassend eine Behandlungskammer (11) und eine Sprüharmanordnung mit einem oder mehreren frei drehenden Tragarmen (16), die mit einem oder mehreren frei rotierenden Sprüharmen (20) zum Antreiben des Tragarms (16) bereitgestellt sind, wobei die Flüssigkeit des Sprüharms (20) in der Schale der Behandlungskammer verteilt wird, dadurch gekennzeichnet, dass die Flüssigkeit auf nicht gleichförmige Weise durch Antreiben des Tragarms (16) in abgestuften Schritten verteilt wird,
wobei der Sprüharm (20) mit mindestens einer Düse (22) bereitgestellt ist, die derart angeordnet ist, dass eine horizontale Reaktionskraftkomponente (F) von dem ausströmenden Strahl aus der Düse ein Moment (C) für den Sprüharm (20) um sein Drehzentrum erzeugt, sowie ein Moment (M) für den Tragarm (16) um sein Drehzentrum, und wobei eine geeignete Reibung am Tragmittel (17, 19) des Sprüharms (20) und des Tragarms (16) zum Erreichen der Drehung des Tragarms (16) in zunehmenden Schritten ausgewählt wird.

2. Geschirrspülmaschine nach Anspruch 1, dadurch gekennzeichnet, dass die gesamte Bewegung des Tragarms als Reaktionskräfte und/oder -momente durch das Aussprühen aus dem Sprüharm erzeugt wird.

3. Geschirrspülmaschine nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die gesamte Flüssigkeit, die dem Tragarm (16) zugeführt wird, angeordnet ist, um durch den Sprüharm (20) hinaus in die Behandlungskammer zu strömen.

4. Geschirrspülmaschine nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass der Tragarm (16) eine geschlossene Struktur ist, die einen Flüssigkeitseinlass (18) und einem Flüssigkeitsauslass (19) aufweist.

5. Geschirrspülmaschine nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass der Sprüharm (20) mit mindestens einer Düse (22) bereitgestellt ist, die derart angeordnet ist, dass eine horizontale Reaktionskraftkomponente (F) von dem Strahl, der aus der Düse strömt, ein Moment (C) für den Sprüharm (20) um sein Drehzentrum sowie ein Moment (M) für den Tragarm (16) um sein Drehzentrum erzeugt.

6. Geschirrspülmaschine nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, dass die Geschirrspülmaschine mit mindestens einem Flüssigkeitszufuhrkanal (17) bereitgestellt ist, an dem der Tragarm zum Drehen angeordnet ist.

7. Geschirrspülmaschine nach Anspruch 6, dadurch gekennzeichnet, dass der Tragarm (16) eine Auslasshülse (19) umfasst, die einen Sprüharm (20) an der Hülse (19) frei drehend unterstützt, und dadurch, dass eine geeignete Reibung an der Zufuhrleitung (17) und an der Hülse (19) gewählt ist, um die Drehung des Tragarms (16) in zunehmenden Schritten zu erreichen.

8. Geschirrspülmaschine nach Anspruch 7, dadurch gekennzeichnet, dass der Tragarm (16) eine geschlossene Struktur ist, die einen Flüssigkeitseinlass (18) aufweist, der an dem Zufuhrkanal (17) angeordnet ist, und einen Flüssigkeitsauslass, der die Auslasshülse (19) ist.

Revendications

1. Lave-vaisselle comprenant une chambre de traitement (11) et un agencement de bras de lavage ayant un ou plusieurs bras de support libres en rotation (16) qui sont pourvus d'un ou de plusieurs bras de pulvérisation (20) libres en rotation pour entraîner le bras de support (16), du liquide étant distribué à travers ledit bras de pulvérisation (20) à la vaisselle dans la chambre de traitement,
caractérisé en ce que
le liquide est distribué de manière non uniforme en entraînant le bras de support (16) par incréments,
le bras de pulvérisation (20) étant pourvu d'au moins une buse (22) agencée de telle sorte qu'une composante de force de réaction horizontale (F) provenant du jet s'écoulant hors de la buse crée un moment (C) pour le bras de pulvérisation (20) autour de son centre de rotation ainsi qu'un moment (M) pour le bras de support (16) autour de son centre de rotation, et
un frottement approprié au niveau des moyens de support (17, 19) du bras de pulvérisation (20) et du bras de support (16) étant choisi de manière à réaliser la rotation du bras de support (16) par incréments.

2. Lave-vaisselle selon la revendication 1, caractérisé en ce que la totalité du mouvement du bras de support est créée en tant que forces de réaction et/ou moments de réaction provenant du jet sortant du bras de pulvérisation.

3. Lave-vaisselle selon la revendication 1 ou 2, caractérisé en ce que la totalité du liquide acheminé au bras de support (16) est prévue pour s'écouler vers l'extérieur jusque dans la chambre de traitement à travers le bras de pulvérisation (20).

4. Lave-vaisselle selon l'une quelconque des revendications 1 à 3, caractérisé en ce que le bras de support (16) est une structure fermée ayant une entrée de liquide (18) et une sortie de liquide (19).

5. Lave-vaisselle selon l'une quelconque des revendications 1 à 4, caractérisé en ce que le bras de pulvérisation (20) est pourvu d'au moins une buse (22) prévue de telle sorte qu'une composante de force de réaction horizontale (F) provenant du jet s'écoulant hors de la buse crée un moment (C) pour le bras de pulvérisation (20) autour de son centre de rotation ainsi qu'un moment (M) pour le bras de support (16) autour de son centre de rotation.

6. Lave-vaisselle selon l'une quelconque des revendications 1 à 5, caractérisé en ce que le lave-vaisselle est pourvu d'au moins un conduit d'alimentation en liquide (17) sur lequel le bras de support est prévu pour tourner.

7. Lave-vaisselle selon la revendication 6, caractérisé en ce que ledit bras de support (16) comprend un manchon de sortie (19) qui supporte un bras de pulvérisation (20) tournant librement sur le manchon (19), et en ce qu'un frottement approprié au niveau du conduit d'alimentation (17) et au niveau du manchon (19) est choisi de manière à réaliser la rotation du bras de support (16) par incréments.

8. Lave-vaisselle selon la revendication 7, caractérisé en ce que le bras de support (16) est une structure fermée ayant une entrée de liquide (18) placée au niveau du conduit d'alimentation (17) et une sortie de liquide constituée par ledit manchon de sortie (19).

Drawing