DE9114093U1 - Spray arm for household dishwashers - Google Patents

Description

EBHZ-90/35 11.11.1991

Ba/Ve

L i c e t i a

Patent Management GmbH

Frankfurt am Main

Description

Spray arm for household dishwashers

The innovation relates to a spray arm for household dishwashers according to the preamble of claim 1.

It concerns in detail the pivot bearing design of the lower spray arm.

Household dishwashers have rotating spray arms on two levels, one above the other, each of which has a removable dish basket. The spray arms are hydraulically driven by the flow of lye generated by the circulation pump. The upper spray arm is suspended and the lower spray arm is stored horizontally or vertically. It can be removed or replaced by the user for cleaning purposes. The sealing of the spray arm at its bearing point is important. Leaking water that escapes here only takes an indirect part in the cleaning process, as it initially flows back into the washing container unused. The greater the amount of leaking water, the lower the so-called spray pressure in the interior of the spray arm and thus its rotation speed and the intensity of its vertically upward rinsing jets.

To avoid the aforementioned circumstances, a "sealing arrangement for a spray arm bearing in dishwashers" is known from DE-PS 27 57 615. The lower spray arm rotates around a fixed pin and is secured in position in the axial direction by a disk with a snap ring. Leakage water losses at the transition from the support tube (water inlet) to the rotary distributor (rotatably mounted spray arm center section) are kept to a minimum by a labyrinth-like plain bearing seal.
A seal between the bearing journal and the relatively large

EBHZ-90/35 11.11.1991 Ba/Ve

The running surface of the rotary distributor, however, is not covered at all. The pin and the spray arm bearing lock are constantly exposed to the hot rinsing solution and must therefore be made of corrosion-resistant material, for example rust-proof and expensive stainless steel. The pin is a dimensionally accurate turned part, the production of which further increases the cost of the spray arm bearing.

Another version of the lower spray arm bearing is known from the G 90 06 913.7. Here, the spray arm also rotates around a fixed pin. Leaking water is simply diverted to the spray arm by a plug-in ring flange on the surrounding outer edge of the inlet pipe and should therefore not be completely lost during the cleaning process.

This design is also expensive and complex for the reasons mentioned above.

The innovation is based on the task of reducing the amount of water leaking at the spray arm bearing point or avoiding it as far as possible.

This object, according to the innovation, is achieved by the characterizing features of claim 1. Further advantageous embodiments of the innovation can be found in the subclaims.

The advantages achieved with the innovation are mainly in the cost-effective design; among other things, the expensive stainless steel bearing pin and its spray arm lock are no longer required. The number of components is kept to a minimum, allowing for simple and quick assembly during production. In practical tests, only small amounts of water leaked out.

An example of the innovation is described in more detail below using an illustration. The drawing shows the basic arrangement and structure of a lower spray arm bearing.

EBHZ-90/35 11.11.1991 ßa/Ve

A right-angled inlet pipe bend 1 connected to the outlet side of a non-installed circulation pump and consisting primarily of alkali-resistant plastic has a molded stop collar 2 and initially the straight free end 3 ¹ shown in dashed lines.

The assembly of the complete spray arm bearing is carried out as follows: A spray arm bushing 4 has a radial, central recessed groove 4 ¹ on the upper face and is pushed onto a bushing 5 with a collar 5'. The underside of said collar 5 ¹ is designed as a sliding surface. The bushing 5 is made of either metal or plastic. The bushing 5 is now pressed tightly together with the spray arm bushing 4 over the free end 3' of the inlet pipe bend 1 up to the stop collar 2 of the said inlet pipe bend 1 and the free end 3' is brought into the shape of the flanged edge 3 by means of a heated stamp over the collar 5' of the bushing 5. This connection is absolutely leak-proof. The spray arm bushing 4 is now held captive and can be rotated easily around the bushing 5. The spray arm bushing 4 is held at a lower height than the running bushing 5 and can therefore be moved axially on it. The recessed groove ⁴¹ reduces the (horizontal) friction surface between the spray arm bushing 4 and the underside of the collar of the running bushing 5 during operation. In a manner not shown, a sliding disk made of metal or plastic can now also be inserted between the two friction surfaces of said components 4, 5' during the aforementioned assembly. The spray arm 6 is now attached to the spray arm bushing 4 in a watertight and form-fitting manner, but can be easily detached from one another. For this purpose, the spray arm 6 and the spray arm bushing 4 can be screwed together using a fine thread or connected to one another using a snap device. (As already mentioned at the beginning, the user can remove the spray arm 6 for cleaning or replacement).

In the resting state, the spray arm bushing 4 together with the spray arm 6 rests on the stop collar 2 or on the inlet pipe bend 1. Under the pressure of the flowing lye, the spray arm 6 and the spray arm bushing 4 are moved in the direction of the arrow

EBHZ-90/35 11.11.1991 Ba/Ve

7 is raised and at the same time the upper sliding surface (with recessed groove 4 ¹ ) of the spray arm bushing 4 is pressed against the lower sliding surface of the collar 5' of the running bushing 5, sealing off leakage water. The supplied lye is now initially deflected horizontally within the spray arm 6 at the flow-optimized point 6', exits vertically upwards from spray nozzles (not shown) and, with the help of recoil nozzles (also not shown), sets the spray arm 6 together with its spray arm bushing 4 in radial rotation around the fixed running bushing 5.

The innovation creates a simple and low-leakage bearing for the lower spray arm 6 of a household dishwasher using just two components (spray arm bushing 4 and bushing 5). (An analogous design, but in a hanging arrangement, is possible for the bearing of the upper spray arm.)

Claims (6)

EBHZ-90/35 11.11.1991 Ba/Ve L i c e &eegr; t i a Patent-Verwaltungs-GmbH Frankfurt/Main Protection claims 1. Spray arm for domestic dishwashers with a rigidly arranged lye supply line in the form of a pipe bend connected to a circulation pump, characterized in that the inlet pipe bend (1) is provided at its free angled end (3') with a molded stop collar (Z) for receiving the bearing of the spray arm (6). 2. Spray arm according to claim 1, characterized in that a bushing (5) with ßund (5') together with a spray arm bushing (4) receiving the spray arm (6) can be pressed onto the free end (S') of the inlet pipe bend (1) up to the stop collar (2) of the inlet pipe bend (1). 3. Spray arm according to claims 1 or 2, characterized in that the free end (3 ¹ ) can be formed into a flanged flange (3) which extends over the collar (5') of the bushing (5). 4. Spray arm according to claim 2, characterized in that a circular, central recess groove (4') is provided on the upper side of the spray arm bushing (4). 5. Spray arm according to claim 2, characterized in that a sliding disk is inserted between the friction surfaces of the collar (5') and the spray arm bushing (4). 6. Spray arm according to claim 2 or one of the following, characterized in that the spray arm bushing (4) is axially displaceable.