EP0245721B1 - Washing machine drum provided with means for wetting the laundry - Google Patents

Description

The invention relates to a drum washing machine with a laundry drum driven more slowly during a wetting phase than during a cleaning phase, and with scooping devices which project into the drum and have hollow drivers and airfoils, which are designed and arranged in such a way that they supply amounts of water in raised positions during the wetting phase at most take in from the outside of the horizontal drum axis and store it temporarily.

Such a drum washing machine is known from DD patent 37 560. There, scoop blades are arranged as scooping devices within the carrier cavities, through which a considerable part of this liquid is to be scooped when passing through the sump of water or alkali standing in the tub, and during the upward movement of this carrier via perforations arranged in the flanks of the carrier in the drum. To convey the interior. Such airfoils and the holes arranged in the flanks of the drivers are not very suitable for effectively wetting the laundry lying inside the drum. The scooped amount of water will flow as soon as it is scooped under the dynamic pressure that arises in the driver cavity and immediately after the driver exits the sump via the perforations in the driver flanks and then flow back along the inner wall of the drum to the sump without significantly wetting the laundry to have.

A washing machine is known from GB-A-390 470, the drum drivers of which have open driver backs and pocket-like bulges in their flanks and in the vicinity of their regions directed towards the drum, drainage holes. However, the bulges lead to the fact that they are absorbed by the open carrier backs Amounts of water are only released into the drum interior when the driver in question is almost at the zenith of its movement path. However, the time remaining for it to be completely emptied is too short. The laundry lying in the drum is then insufficiently or too slowly wetted.

US-A-3 201 958 describes a washing machine whose drum drivers are divided in the direction slow to the drum axis.

GB-A-673 887 describes a washing machine, the drum drivers of which have open backs with additional blades. However, their flanks are flat, in most of the exemplary embodiments set at an angle to the drum radius and perforated on the entire surface. In the embodiment shown in FIG. 3, however, one flank of the driver (namely the one on which the airfoil is rooted) is set radially and is not perforated. Here, the amount of water scooped in the driver can be carried along over a certain angular movement of the drum, quite in contrast to the other exemplary embodiments, in which the amount of water absorbed immediately flows back through the flood holes and underflows the laundry instead of irrigating it from above. The drivers according to FIG. 3 of GB-A-673 887 only release their amount of water from a position at a height above the horizontal drum axis to the drum interior, somewhat late; because when swinging due to the rotation of the drum even at a reduced wetting speed, the rain is driven to the opposite drum wall when it is released from this height. The example of FIG. 3 also has the disadvantage that the desired wetting function is suspended when the drum rotates in the opposite direction, so that the layering of the laundry required for good and quick wetting is significantly impaired.

The invention has for its object to improve a drum washing machine of the type mentioned so that the amount of water used in each case wets the laundry stored in the drum as quickly as possible and without losses.

According to the invention, this object is achieved in that the driver cavities are delimited by a driver back arranged in the drum contour and having the airfoils and divided into chambers transverse to the drum axis, to which at least one airfoil is assigned in each case, that the airfoils of adjacent chambers have different directions of rotation Assigned to the drum and aligned opposite to the airfoil of the adjacent chamber and that the scooping devices are designed and arranged in such a way that during the wetting phase they at the earliest the amount of water from a height in the region of the second eighth of the drum rotation, calculated from the lowest point until no later than the end of the seventh eighth of the drum rotation into the drum interior.

Such a design and arrangement of scooping devices can for the first time ensure that the laundry is irrigated from above within a very short time, avoiding losses of the scooping water quantities, i.e. is wetted. The fact that the airfoils are distributed over at least two chambers and are oriented opposite to the airfoil of the neighboring chamber enables the desired irrigation effect in both directions of drum rotation to be ensured in a simple manner. The wetting of the laundry takes place more intensively because it is layered again and again in the drum.

Since washing is to be carried out with as little use of water as possible, there is only a sump of low height at the bottom of the tub, which protrudes only a little into the drum or only touches the outside of the drum. Laundry that relies solely on contact with this small amount of water during the wetting phase can only wet very slowly and unevenly. With water quantities whose levels do not reach the inside of the drum, the laundry even stays completely dry. The irrigation of the laundry according to the invention by suitably designed scooping devices can considerably accelerate the wetting process or even make it possible in the first place and ensure uniform wetting of the laundry.

The invention can be developed in a particularly advantageous manner in that the drivers are part of the scooping devices and have airfoils and flood holes on their bottoms directed towards the drum. Scoops designed in this way do not occupy their own space on the circumference of the drum and can be easily represented in terms of production technology. In addition, drivers designed for scooping devices form excellent possibilities for temporarily storing the required quantities of water until the corresponding driver is located far enough above the laundry stored in the drum. From this position, the temporarily stored amount of water can rain through the flood holes in a finely divided form over the laundry.

Carriers designed in this way are advantageously further developed in that the airfoils partially close off the carrier cavities which are open towards the outside of the drum on at least one of their edges running parallel to the axis of rotation of the drum. As a result, the driver cavities are closed well enough to the outside, so that scooped liquid cannot run out prematurely and cannot flow out again.

Another development of the invention has the same advantages, in which the drivers are unbroken on their flanks facing inward from the drum and their flanks form troughs together with adjacent lateral surfaces. Such drivers store the scooped water up to about the level of the horizontal drum axis in their troughs and release this amount of water as soon as the driver tips over with its free end. As a result, the laundry is also advantageously irrigated from above and completely wetted in a very short time during both drum rotation directions.

So that the laundry lying on the bottom of the drum does not soak up the amount of water temporarily stored in the trough in a concentrated manner in an ineffective manner, before a sprinkling effect can occur, when the driver is gradually raised, it is advantageous for drivers designed in this way if the troughs are covered with partially permeable plates are. Such plates protect the temporarily stored amount of water from being sucked up prematurely by the laundry lying on the floor. It has been shown that the same amounts of water wet the laundry more quickly if it is finely distributed over the laundry instead of locally limited suction processes.

, vorzugsweise 0,67 $$\frac{\text{m}}{\text{s}}$$

, ergibt. Erst bei so langsamer Umfangsgeschwindigkeit fallen Zentrifugalkräfte nicht mehr ins Gewicht, die eine genügend feine Verteilung des Wassers über die Wäsche verhindern würden und sind die Beschleunigungs- und Trägheitsverhältnisse der geschöpften Wassermengen aufeinander abgestimmt. Bei einem Trommeldurchmesser von 476 mm ergeben sich daher eine optimale Drehzahl n_opt = 27 min⁻¹ und eine maximale Drehzahl n_max = 30 min⁻¹.A drum washing machine of the type according to the invention is advantageously further developed in that the rotational speed of the laundry drum during the wetting phase is set such that a circumferential speed of at most 0.75 is found on the drum shell $$\frac{\text{m}}{\text{s}}$$

, preferably 0.67 $$\frac{\text{m}}{\text{s}}$$

, results. Only when the peripheral speed is so slow do centrifugal forces no longer play a role, which would prevent the water from being distributed sufficiently finely over the laundry, and are the acceleration and inertia ratios of the scooped water quantities coordinated. With a drum diameter of 476 mm, this results in an optimal speed n _opt = 27 min⁻¹ and a maximum speed n _max = 30 min⁻¹.

• Fig. 1 eine schematische, aufgebrochene Darstellung des Laugenbehälters und der Trommel einer Trommelwaschmaschine,
• Fig. 2 bis
  Fig. 4 vier verschiedene Positionen eines erfindungsgemäß ausgestatteten Mitnehmers,
• Fig. 5 und
  Fig. 6 (Ansicht in Blickrichtung des Pfeiles VI) eine andere Ausgestaltung der Trommelwandung und des Mitnehmers derselben Art wie die Schöpfvorrichtungen in Fig. 2 bis 4,
• Fig. 7 eine geschnittene Teilansicht einer Wäschetrommel mit einer anderen Ausbildungsform von Mitnehmern und
• Fig. 8 eine andere Ausgestaltung eines Mitnehmers derselben Art wie die in Fig. 7 dargestellten.

The invention is explained below on the basis of the exemplary embodiments illustrated in the drawing. Show it:

• 1 is a schematic, broken-open representation of the tub and the drum of a drum washing machine,
• Fig. 2 to
  4 shows four different positions of a driver equipped according to the invention,
• Fig. 5 and
  6 (view in the direction of arrow VI) another embodiment of the drum wall and the driver of the same type as the scooping devices in FIGS. 2 to 4,
• Fig. 7 is a partial sectional view of a laundry drum with another form of training of carriers and
• Fig. 8 shows another embodiment of a driver of the same type as that shown in Fig. 7.

The tub 1 in FIG. 1 contains in its upper area a filling opening 2 for detergent introduced from a detergent dispenser 3 together with feed water.

The bottom of the lye container 1, which is kept as close as possible to the drum 4, has a recess 5 in which the heating elements 6 required for heating the lye are arranged. At the deepest point of the recess 5 there is an outlet opening 7 which is kept closed by a closure body 8 as long as a drain pump (not shown) does not suck on the drain line 9. This closure body 8 has the task of keeping the space below the drain opening 7 closed as long as there is detergent required for washing the laundry inside the tub.

In the increasing endeavor to use less and less water and detergent for washing, the amount of water required for washing has recently decreased so that the washing drum 4 is now only slightly immersed in the lye located at the bottom of the tub 1. However, this creates a hitherto unknown problem: the laundry 10 stored on the bottom of the drum 1 does not come into sufficient contact with the alkali so that the laundry is wetted only very slowly and very incompletely. This will jeopardize the washing result.

It has already been proposed (DE-OS 33 24 481) to reduce the drum speed to a value (e.g. 30 min⁻¹) below the washing speed (e.g. 50 min⁻¹) during the wetting phase, so that the laundry item is better and faster moistened. However, this method only achieves the desired effect if a certain lye level can be guaranteed in the laundry drum, at which the laundry is still immersed sufficiently in the lye. However, recent developments also fall below a minimum level that is still permissible for this purpose, so that the known method - used alone - can no longer achieve the desired success.

According to the invention, scoop devices 12 are arranged on the drum circumference in the area of the drivers, which when the drum is rotated, for example in the direction of the arrow 13, can fill the respective intermediate storage space, here the driver 11, from the solution stock in the recess 5. During the upward movement of the driver, this scooped amount of water is first temporarily stored and only released into the drum interior via outlet openings in the intermediate storage space when the intermediate storage space has reached a certain height above the laundry 10 lying in the drum 4. The arrows 14 indicate the manner in which the water so raised rains over the laundry 10.

2, the dash-dot driver 11 of the drum 4 is just in its lowest position. Here he dips with his scooping devices into the lye inside the recess 5 under the bottom of the tub 1 and already absorbs some of the lye. When turning further in the direction of arrow 13, the scooping devices 12 fill the interior of the driver 11 higher than would occur in the static state.

When the driver 11 (FIG. 3) is raised further as a result of the rotation of the drum 4 in the direction of the arrow 13, the driver passes through positions below the horizontal drum axis 15 (in the second eighth of the rotation). In each of these positions, the cavity of the catch 11 stores a certain amount of water 16 until the catch 11 assumes a position, in this exemplary embodiment in the third eighth above the axis of rotation 15 of the drum, in which the amount of water 16 borders the bottom of the holes 17 in the testicle 18 of the driver 11 reached. From there, the water 16 flows from the driver 11 dropwise through the holes 17 into the interior of the drum 4. This process is shown in Fig. 4, which also shows the raindrops 19, which lead to the even and complete wetting of the laundry in an impressive manner. Before the driver 11 has reached the seventh eighth of the rotation of the drum 4, the interior of the driver 11 has emptied and can again draw water from the supply located at the bottom in the tub 1 after passing through the remaining rotation.

For the example in FIGS. 2 to 4, there is a rule for the dimensioning of the distance between the mutually facing edges of the blade plates 12 designed as scooping devices. This distance should be approximately the same order of magnitude as the distance between the outer edge of the most distant holes in the Cross section of the carriers considered. If the spacing of the blade edges is greater than the spacing of the hole edges, then the volume of the water temporarily stored in each carrier is comparatively small and washing of the laundry only begins when the carrier is located above the horizontal drum axis 15. However, if the distance between the blade edges is mine than the distance between the edges of the holes, then the volume of the temporarily stored water is greater and the irrigation begins below the horizontal Drum axis. If the position of the driver is still far below the horizontal drum axis at the beginning of the water discharge from the flood holes, there is a risk that part of the rain water will not hit the laundry or that the escaping water will not detach from the driver wall, but on it flows down. Then no effective wetting could occur. An optimum is therefore to be found between the two extremes, on which the peripheral speed of the drum casing also has an influence.

Umfangsgeschwindigkeit eingestellt. Es hat sich gezeigt, daß zum Benetzen der Wäsche in einer solchen Trommel die optimale Drehzahl bei 27 min⁻¹ = 0,67 $$\frac{\text{m}}{\text{s}}$$

Umfangsgeschwindigkeit liegt. Als Cbergrenze der Umfangsgeschwindigkeit, bei der noch eine brauchbare Benetzung stattfindet, sollte bei einer solchen Wäschetrommel 0,75 $$\frac{\text{m}}{\text{s}}$$

gelten (= 30 min⁻¹).For example, in a laundry drum equipped according to the invention with a diameter of approximately 475 mm, the washing speed is 52 min -1 = 1.3 $$\frac{\text{m}}{\text{s}}$$

Peripheral speed set. It has been shown that for wetting the laundry in such a drum the optimal speed at 27 min⁻¹ = 0.67 $$\frac{\text{m}}{\text{s}}$$

Peripheral speed is. The upper limit of the peripheral speed at which usable wetting still takes place should be 0.75 in such a washing drum $$\frac{\text{m}}{\text{s}}$$

apply (= 30 min⁻¹).

The exemplary embodiment shown in FIGS. 5 and 6 for scooping devices on the driver 11 contains, as shovel blades, a plurality of ladles 20 which consist of cut-open features in the sheet metal of the driver back 26, which is part of the drum jacket 21. The ladles 20 are arranged in two rows next to one another and offset from one another parallel to the axis of rotation 24 of the drum 4.

Above these rows of ladles 20, the roof-shaped driver 11 is arranged in the interior of the drum 4 and has a plurality of flood holes 17, from which the amount of water drawn can rain over the laundry. The roof part of the driver has fastening tabs 22 on its foot edges, which are inserted through suitable slots in the drum jacket and are bent outside towards the drum jacket

The interior of the driver 11 is divided by bulkheads 23 into several chambers 25, which are covered by the driver back 26 in FIG. 6. A ladle 20 is assigned to each chamber 25. The ladles of adjacent chambers are directed opposite each other, so that the 1st, 3rd, 5th etc. chamber in one drum direction of rotation, and the 2nd, 4th, 6th etc. chamber in the other direction of rotation are filled with water and their Empty the contents from the raised positions above the laundry.

The laundry drum 4 shown in detail in FIG. 7 contains, for example, six drivers, of which three drivers 27 are shown here. Instead of a number of six, however, the drum can also contain three drivers as usual.

These drivers are trough-shaped on their flanks, so that, as the driver in the middle position shows, water can be temporarily stored in the upper trough 28 and raised to a height from which it is on the trough edge on the inside of the drum on the head of the driver 27 can rain on the laundry. A partially permeable plate 29, which covers the trough 28, is shown on the driver located in the middle position. The partial permeability of the plate 29 results from holes 30, which are preferably arranged in the edge region of the plate, so that the water can be well absorbed from the swamp in the trough on the one hand and can escape from the trough via the driver's head on the other hand. This plate prevents the laundry lying at the bottom of the laundry drum from already sucking the trough 28 before the driver 27 has been lifted up. As a result, the laundry would soak itself very strongly, but only in a very limited area, and the other areas of the laundry remained almost dry. A more effective wetting of the laundry, as already explained above, only results from sprinkling the laundry from above.

Another embodiment of a driver 31 with the same function as the driver 27 described with reference to FIG. 7 is shown in FIG. 8. It contains a support strip 32 with an edge bead 33 pointing inward of the drum. On its undersides, the edge bead has slit-like depressions which serve to receive a partially permeable cover plate 34 for the troughs 35 which result on both sides of the support strip 32. The jacket-side edges of the cover plates 34 have bent tabs 36, which are inserted into slots in the jacket plate 37 of the laundry drum 4.

The cover plates 34 have large holes 38 in the area near the drum casing 37, which enable rapid absorption of water from the sump into the troughs 35, and small holes 39 in the area near the edge bead 33, which allow metered discharge of the scooped water from the troughs allow.

Any modification of the scooping devices is possible within the scope of the invention. These do not necessarily have to be functionally and constructively related to the drivers, but can also be used as special facilities be distributed around the circumference of the drum. For example, in the direction of rotation of the drum, blades can be arranged in front of drivers according to FIGS. 7 and 8 on the drum jacket, which blades are still immersed in liquid when their level only affects the drum jacket. If, by means of any devices on the drum, certain amounts of water are drawn from the storage located at the bottom of the tub and lifted to such an extent that the amounts poured down onto the laundry from above, the inventive idea is met.

Claims (7)

1. Drum washing machine with a laundry drum, which is driven more slowly during a wetting phase than during a cleaning phase, and with scoop devices, which project into the drum and display hollow entraining members and scoop vanes and which are so constructed and arranged that they receive and intermediately store quantities of water from outside in raised position to at most the horizontal drum axis during the wetting phase, characterised thereby, that the entraining cavities (25) are bounded by an entraining member back (26), which is arranged in the drum outline (21) and displays the scoop vanes, and subdivided transversely to the drum axis into chambers (25), which are each associated with at least one respective scoop vane (20), that the scoop vanes of respectively neighbouring chambers are associated with different directions of rotation of drum and oriented oppositely to the scoop vane of the neighbouring chamber and that the scoop devices (11, 12, 20, 27, 31) are so constructed and arranged that they deliver the quantities of water into the interior of the drum during the wetting phase at the earliest from a height in the region of the second eighth of the revolution of the drum, as reckoned from the lowest point, to at the latest at the end of the seventh eighth of the revolution of the drum.

2. Drum washing machine according to claim 1, characterised thereby, that the entraining members (11) display flood holes (17) at their walls facing inwards of the drum.

3. Drum washing machine according to claim 2, characterised thereby, that the scoop vanes (12) partially close off the entraining cavities, which are open towards the outer side of the drum, at at least one their edges extending parallelly to the rotational axis (24) of the drum (4).

4. Drum washing machine according to claim 2, characterised thereby, that the scoop vanes (20) are stamped out of the entraining member back (26), which is arranged in the drum outline (21), in the rotational direction (13) of the drum (4).

5. Drum washing machine according to claim 1, characterised thereby, that the entraining members (27, 31) are interrupted at their flanks facing inwards of the drum and their flanks together with neighbouring casing surfaces form troughs (28, 35).

6. Drum washing machine according to claim 5, characterised thereby, that the troughs (28, 35) are covered by partially permeable plates (29, 34).

7. Drum washing machine according to one of the preceding claims, characterised thereby, that the rotational speed of the laundry drum (4) during the wetting phase is so set that a peripheral speed of at most 0.75 metres per second, preferably 0.67 metres per second, results at the casing of the drum.

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