US20130255734A1

US20130255734A1 - Spray arm for a dishwasher with two spray arm parts

Info

Publication number: US20130255734A1
Application number: US13/854,277
Authority: US
Inventors: Heinz Hermann; Marc Vogt
Original assignee: Etimex Technical Components GmbH
Current assignee: Etimex Technical Components GmbH
Priority date: 2012-03-30
Filing date: 2013-04-01
Publication date: 2013-10-03
Also published as: CN104302222B; WO2013143516A1; ES2688870T3; EP2830475B1; EP2830475A1; CN104302222A; PL2830475T3; DE102012006379A1

Abstract

In a spray arm for a dishwasher, comprising a first spray arm part and a second spray arm part, of which the first spray arm part comprises a groove which extends substantially along the circumference of the first spray arm part, said groove being formed by a first, inner groove wall and a second, outer groove wall, and of which the second spray arm part comprises a web wall which extends substantially along the circumference of the second spray arm part and engages with the groove, the web wall comprises a first latching element which, in order to establish a latching connection between the first and the second spray arm part, is designed to interact with a second latching element which is located on one of the groove walls.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority on U.S. Provisional Patent Appl. No. 61/739,306 filed on Dec. 19, 2012, the entire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates to a spray arm for a dishwasher, comprising a first spray arm part and a second spray arm part, of which the first spray arm part comprises a groove which extends substantially along the circumference of the first spray arm part.
2. Description of the Related Art
In dishwashers, in particular in those used as domestic appliances, rotating spray arms are provided for supplying and distributing washing water in an associated washing compartment. The spray arms are usually assembled using two spray arm parts which enclose a cavity. The washing water is introduced into the cavity and is thereafter sprayed into the washing compartment of the dishwasher by means of nozzles, the nozzles being located on at least one of the spray arm parts.
In order to ensure proper functioning of such a spray arm, its cavity has to be enclosed tightly sealed by the two spray arm parts. Furthermore, the manufacture and the assembly of the spray arm parts must be cost-effective, as the cost pressure in the manufacturing and the assembly of such dishwashers is very high, particularly in the field of domestic appliances but also in the field of industrial appliances.
The object underlying the invention is to provide a dishwasher with a spray arm, of which the spray arm parts may be manufactured and assembled in a particularly cost-effective way, but at the same time meet the requirements in respect of leaktightness over the service life.

SUMMARY OF THE INVENTION

The object is achieved according to the invention with a spray arm for a dishwasher, comprising a first spray arm part and a second spray arm part, of which the first spray arm part comprises a groove which extends substantially along the circumference of the first spray arm part, said groove being formed by a first, inner groove wall and a second, outer groove wall, and of which the second spray arm part comprises a web wall which extends substantially along the circumference of the second spray arm part and engages with the groove, the web wall comprising a first latching element which, in order to establish a latching connection between the first and the second spray arm part, is designed to interact with a second latching element which is located on one of the groove walls.
The solution according to the invention provides a cavity which can be manufactured cost-effectively and is sealed toward the outside and conducts fluid. The cavity herein is already sealed without any additional measures upon connection of the two spray arm parts to one another. No separate production step is required in order to seal the components joined with one another. The sealing is ensured only by the groove and the web wall inserted into it, with the components at the same time being permanently coupled to one another by means of the latching connection provided. The inner groove wall serves as an additional support for the web wall and in this way increases the strength of the connection. The structure of the groove provided by the invention creates double side walls in the spray device. This is advantageous with a view to torsional stiffness and the stability of the assembled spray arm. The double design of the wall is implemented at the points exhibiting the greatest stress, shearing forces and pressure impulses and at the same time the lowest bending strength.
In particular, the solution according to the invention does not necessitate any separate process steps for sealing or joining, as in, for instance, paddle welding, vibration welding or overmolding of conventional spray arm parts. Additionally, the risk of leaks or distortion as indeed occurs in conventional manufacturing methods for spray arms is avoided. As a result, according to the invention, the requirements in terms of technical equipment for the manufacture and assembly, and the associated investment costs, are reduced. Moreover, the solution according to the invention can be very well integrated into any automated manufacturing process with short cycle times, in particular with a view to a short-cycle injection molding process for the manufacture of the respective spray arm parts.
Based on the solution according to the invention, a spray arm may be manufactured which also satisfies high esthetic requirements, as exist today for a spray arm, this being a visible part of a dishwasher.
To this end, in particular the first latching element is embodied on the outside of the web wall and the second latching element is embodied on the second, outer groove wall. The latching connection of this kind is located, hidden from the viewer from the outside, between the outer groove wall and the web wall. Indeed, in this solution no latch cams, as may be conventionally known from other applications, are identifiable. Because such latch cams should not be visible, such latch cams have hitherto been used only on, for instance, spray arms of the so-called third spray level, where the spray arm is located very close to the ceiling of the washing compartment. There, not only is the visibility of the spray arm is limited, but there is also no requirement for a high level of leaktightness.
In the solution according to the invention, it is particularly preferable that the second, outer groove wall is designed to be higher than the first, inner groove wall. In this instance, the outer groove wall extends particularly far beyond the web wall, with sufficient space for the location of a latching connection thus being available below. At the same time, the groove walls of different height permit the web wall to be inserted into the groove in a stepped manner, said web wall being first aligned along the outer groove wall and only then being inserted into the rear or deeper section of the groove for the purpose of sealing by means of the inner groove wall. This stepped insertion into the groove is particularly advantageous with a view to an automated assembly and the leaktightness of the functional group thus achievable.
In order to further facilitate the assembly of the functional group according to the invention, the first, inner groove wall is preferably also designed with an insertion chamfer on its rim facing the web wall for insertion of the web wall into the groove, the second, outer groove wall is preferably also designed with an insertion chamfer on its rim facing the web wall for insertion of the web wall into the groove, and/or the web wall is preferably also designed with an insertion chamfer on at least one of its rims facing the groove walls for insertion of the web wall into the groove.
For the latching connection according to the invention, the first latching element is preferably designed as a detent lug and the second latching element as a detent recess. With a latching geometry of this kind, a high strength of the latching connection may be achieved with a comparatively narrow latching width.
The first latching element and the second latching element are furthermore preferably designed to extend substantially along the entire circumference of the first and the second spray arm part. By means of the thus substantially completely surrounding latching connection, the two spray arm parts are coupled together in a uniformly tight manner along their entire circumference. The risk of any local detachment, loosening or bursting open of the connection is thus minimized, given at the same time a comparatively low locking force. The surrounding latching may herein be advantageously combined on at least one of the spray arm parts with a surrounding sealing lip, which in the latching process with its counterpart is compressed and deformed along the entire circumference. Such a sealing lip is, however, not mandatory. Rather, the surrounding latching according to the invention especially additionally forms a labyrinth which significantly contributes to the mutual sealing of the two spray arm parts. The solution according to the invention thus achieves an optimum balance between joining force and deformation and leaktightness. The particular embodiment of the latching geometry according to the invention additionally contributes toward leaktightness being ensured along the entire circumference of the two spray arm parts.
Moreover, it is advantageous that the first latching element and the second latching element are designed with an interruption by a short gap at predetermined spacings along the circumference of the first and the second spray arm part. Such interruptions of the latching elements advantageously extend over a gap of 0.5 cm to 1.5 cm, particularly preferably approx. 1.0 cm, and are of advantage in particular with a view to the shaping of the injection molds used for the spray arm parts.
Finally, the solution according to the invention is also outstandingly suited to providing at least one channel leading from the outside into the groove for accommodating a mass connecting the first spray arm part with the second spray arm part. The mass introduced into the channel may ensure an additional means of sealing and a cohesive connection of the two spray arm parts, if so desired.
In the following, exemplary embodiments of the solution according to the invention are explained in more detail with reference to the attached schematic drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first perspective view of a first spray arm according to the invention with its two spray arm parts prior to assembly.

FIG. 2 shows a second perspective view of the spray arm parts shown in FIG. 1.

FIG. 3 shows a perspective view of the spray arm parts shown in FIG. 1 after assembly to form the complete spray arm.

FIG. 4 shows the cross section IV-IV in FIG. 1.

FIG. 5 shows the cross section V-V in FIG. 3.

FIG. 6 shows the detail VI in FIG. 5.

FIG. 7 shows the view shown in FIG. 5 for a variant of a spray arm according to the invention.

FIG. 8 shows a perspective view of a second spray arm according to the invention with its two spray arm parts prior to assembly.

FIG. 9 shows a perspective view of the spray arm parts shown in FIG. 8 after assembly to form the complete spray arm.

FIG. 10 shows a perspective view of a third spray arm according to the invention with its two spray arms prior to assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The figures show a spray arm 10 of a domestic dishwasher which is not illustrated, comprising a vertical hollow-cylindrical hub section 12, with two arm sections 14 and 16 extending horizontally therefrom in opposite directions. When fitted to the dishwasher, the spray arm 10 is supplied through the hub section 12 with water under pressure, which water then sprays out through the nozzles 18 which are arranged distributed on the spray arm 10.
The nozzles 18 are distributed on the upper side 19 of an upper, shell-shaped spray arm part 20 and, if appropriate, also on the lower side 22 of a lower, also shell-shaped spray arm part 24. The spray arm parts 20 and 24 herein are made of plastic by means of injection molding or alternatively of metal, in particular of stainless steel, by means of deep-drawing, and are each placed against one another by way of their shell shape such that a cavity 26 is created.
The region of the joint or connection between the two shells placed against one another in such a way is sealed and coupled in a form-fitting manner. To this end, a groove 28 which extends substantially along its circumference is embodied on the upper spray arm part 20, said groove being formed by a first, inner groove wall 30 and a second, outer groove wall 32. Furthermore, a web wall 34 which also extends substantially along its entire circumference and engages with the groove 28 is embodied on the lower spray arm part 24.
The web wall 34 is, at its top, designed to be so high that it is sealed against the upper spray arm part 20 right up to the base of the groove 28 and there in a first, upper seal region 36 (refer to FIG. 6) by pressing in a force-fitting manner. Furthermore, the groove 28 is designed to be so narrow that the web wall 34, when inserted into the groove 28, is laterally forced against the inner groove wall 30, where it is also sealed in a second lateral seal region 38 (refer again to FIG. 6) against the upper spray arm part 20. Alternatively, the web wall 34 is designed to be so high and/or wide that it lies against the walls of the groove 28 without any major contact pressure. In this instance, sealing between the upper spray arm part 20 and the lower spray arm part 24 is essentially achieved solely as a result of the labyrinth-type geometry of groove 28 and web wall 34.
A latching connection 40 is further achieved between the upper spray arm part 20 and the lower spray arm part 24, by means of which connection the two parts are coupled to one another in a form-fitting manner. The form-fitting coupling is made without a separate production step when joining the spray arm part 20 and the spray arm part 24 during assembly of the spray arm 10. For this purpose, the web wall 34 on the lower spray arm part 24 comprises a first latching element 41 on its outside which interacts with a second latching element on the inside of the outer groove wall 32. The latching connection 40 of this kind is not visible to anyone viewing the spray arm 10 from the outside.
The first latching element 41 is designed as a detent lug and the second latching element 42 as a detent recess, both extending substantially along the entire circumference of the first and the second spray arm part 20 or 24, respectively, and only being interrupted by a short gap 44 at predetermined spacings along the circumference.
The second, outer groove wall 32 is designed to be higher than the first, inner groove wall 30 and extends far beyond the web wall 34 when the lower spray arm part 24 is brought together with the upper spray arm part 20. Moreover, the first, inner groove wall 30 is designed with an insertion chamfer 46 on its rim facing the web wall 34 for insertion of the web wall 34 into the groove 28, the second, outer groove wall 32 is designed with an insertion chamfer 48 on its rim facing the web wall 34 also for insertion of the web wall 34 into the groove 28, and the web wall 34 itself is designed with an insertion chamfer 50 and 52 on each of its two rims facing the groove walls 30 and 32. By means of these insertion chamfers 46, 48, 50 and 52, the insertion of the web wall 34 into the groove 28 overall is also possible in the event of relatively large dimensional differences between spray arm part 20 and spray arm part 24.
FIG. 7, finally, shows a variant of a spray arm 10 in which a plurality of channels 54 for accommodating a mass connecting the first spray arm part 20 with the second spray arm part 24 are distributed along the circumference on the upper rim region of the upper spray arm part 20. The mass may be introduced into the channels 54 during the assembly process, in particular in order to be distributed within the groove 28 above the web wall 34, for additional sealing and for cohesive connection of the two spray arm parts 20 and 24.
FIGS. 8 and 9 show a spray arm 10, of which the spray arm part 20 is also designed with a groove 28, an inner groove wall 30 and an outer groove wall 32. A substantially vertical slot 56 is formed in the outer groove wall 32 approximately in the center of each arm section 14 and 16. The slot 56 extends substantially along the entire height of the groove wall 32 and is open toward the outside and/or accessible from outside. A fin 58 is inserted in the slot 56 of this kind in a form-fitting manner when the two spray arm parts 20 and 24 are joined, said fin 58 being embodied at a corresponding position on the exterior of the web wall 34 of the lower spray arm part 24. The fins 58 of this kind, of which a total of four are located on the circumference of the spray arm part 24, in interaction with the four associated slots 56 on the upper spray arm part 20, serve as stiffening elements and in particular prevent any distortion of the spray arm 10 when water passes through it in the operational state and thus sets it in rotational motion.
FIG. 10 shows a spray arm 10 in which, in a functionally similar manner, vertical slots 56 are embodied on the inner groove wall 30 and fins 58 are embodied on the inner side of the web wall 34. This arrangement of the slots 56 and the form-fitting ribs 58 results in a stiffening effect which is not visible from outside.
In concluding, it should be observed that all features mentioned in the application documents and, in particular, in the dependent claims are to be protected in their own right individually or in any combination with one another, notwithstanding the formal references made to one or more specific claims.

Claims

What is claimed is:

1. Spray arm (10) for a dishwasher, comprising a first spray arm part (20) and a second spray arm part (24), of which the first spray arm part (20) comprises a groove (28) which extends substantially along the circumference of the first spray arm part (20), said groove being formed by a first, inner groove wall (30) and a second, outer groove wall (32), and of which the second spray arm part (24) comprises a web wall (34) which extends substantially along the circumference of the second spray arm part (24) and engages with the groove (28), the web wall (34) comprising a first latching element (41) which, in order to establish a latching connection (40) between the first and the second spray arm part (20; 24), is designed to interact with a second latching element (42) which is located on one of the groove walls (30; 32).

2. Spray arm of claim 1, wherein the first latching element (41) is embodied on the outside of the web wall (34) and the second latching element (42) is embodied on the second, outer groove wall (32).

3. Spray arm of claim 2, wherein the second, outer groove wall (32) is designed to be higher than the first, inner groove wall (30).

4. Spray arm of claim 3, wherein the first, inner groove wall (30) is designed with an insertion chamfer (46) on its rim facing the web wall (34) for insertion of the web wall (34) into the groove (28).

5. Spray arm of claim 4, wherein the second, outer groove wall (32) is designed with an insertion chamfer (48) on its rim facing the web wall (34) for insertion of the web wall (34) into the groove (28).

6. Spray arm of claim 5, wherein the web wall (34) is designed with an insertion chamfer (50, 52) on at least one of its rims facing the groove walls (30; 32) for insertion of the web wall (34) into the groove (28).

7. Spray arm of claim 6, wherein the first latching element (41) is designed as a detent lug and the second latching element (42) as a detent recess.

8. Spray arm of claim 7, wherein the first latching element (41) and the second latching element (42) are designed to extend substantially along the entire circumference of the first and the second spray arm part (20; 24).

9. Spray arm of claim 8, wherein the first latching element (41) and the second latching element (42) are designed with an interruption by a short gap (44) at predetermined spacings along the circumference of the first and the second spray arm part (20: 24).

10. Spray arm according of claim 9, wherein at least one channel (54) leads from the outside into the groove (28) for accommodating a mass connecting the first spray arm part (20) with the second spray arm part (24).

11. Spray arm of claim 1, wherein the second, outer groove wall (32) is designed to be higher than the first, inner groove wall (30).

12. Spray arm of claim 1, wherein the first, inner groove wall (30) is designed with an insertion chamfer (46) on its rim facing the web wall (34) for insertion of the web wall (34) into the groove (28).

13. Spray arm of claim 1, wherein the second, outer groove wall (32) is designed with an insertion chamfer (48) on its rim facing the web wall (34) for insertion of the web wall (34) into the groove (28).

14. Spray arm of claim 1, wherein the web wall (34) is designed with an insertion chamfer (50, 52) on at least one of its rims facing the groove walls (30; 32) for insertion of the web wall (34) into the groove (28).

15. Spray arm of claim 1, wherein the first latching element (41) is designed as a detent lug and the second latching element (42) as a detent recess.

16. Spray arm of claim 1, wherein the first latching element (41) and the second latching element (42) are designed to extend substantially along the entire circumference of the first and the second spray arm part (20; 24).

17. Spray arm of claim 16, wherein the first latching element (41) and the second latching element (42) are designed with an interruption by a short gap (44) at predetermined spacings along the circumference of the first and the second spray arm part (20: 24).

18. Spray arm according of claim 1, wherein at least one channel (54) leads from the outside into the groove (28) for accommodating a mass connecting the first spray arm part (20) with the second spray arm part (24).