EP2053152A1

EP2053152A1 - Washing or drying machine with a drum provided with movable lifters

Info

Publication number: EP2053152A1
Application number: EP07118888A
Authority: EP
Inventors: Tobias Rieger
Original assignee: Whirlpool Corp
Current assignee: Whirlpool Corp
Priority date: 2007-10-19
Filing date: 2007-10-19
Publication date: 2009-04-29
Anticipated expiration: 2027-10-19
Also published as: ES2361860T3; DE602007014220D1; PL2053152T3; EP2053152B1

Abstract

A washing or drying machine comprises a rotating drum (10) and at least a lifter (12) arranged on an inner peripheral surface of the drum (10). The lifter (12) is movable and it comprises a base portion (12a) fixed to the drum (10) and a movable portion (12b) hinged to said base portion (12a).

Description

The present invention relates to a washing or drying machine comprising a tub, a rotating drum provided in the drum and at least a lifter arranged on an inner peripheral surface of the drum.
It is well known in the art of horizontal axis washers the use of a plurality of lifters arranged on an inner peripheral surface of the rotating drum while extending axially along the rotating drum. To more rapidly and effectively washing clothes contained in the rotating drum, the lifters raise the clothes towards the top of the rotating drum, and then release the clothes to cause the clothes to be dropped to the bottom of the rotating drum, in accordance with the rotation of the rotating drum.
The shape and dimension of the lifter is a sort of compromise between the need of assuring an efficient washing process and the need of avoiding damages to clothes.
The above compromise is difficult to reach; bigger lifters assure a better wetting process (therefore a better chemical interaction between the detergent and the textiles) but on the other hand are responsible for higher mechanical stresses to the fibers, increasing tangling and wrinkling effect. Moreover, if bigger lifters are beneficial in the tumbling phase (i.e. during actual washing), they can cause problems of laundry even distribution before the spinning phase (dewatering), increasing the unbalance of the drum.
An object of the present invention is to provide a washing machine of the type mentioned at the beginning of the description which does not present the above problems.
Such object is obtained thanks to the features listed in the appended claims.
According to the present invention, the lifter is divided into a fixed part attached to the drum wrapper and a movable part which can rotate or slide in radial direction. Between the movable part and the fixed part one or several springs are interposed which urge the movable part in extended position. Therefore the overall height of the lifter is changing depending on the position of the movable part (extended position-retracted position). The spring force and mass of the movable part is predetermined so that the movable part is moving in and out during different steps of the wash process to increase gentleness, wash performance and water extraction performance. An overall benefit of the technical solution according to the present invention is an increased drum capacity (measured with lifters in retracted position)
As far as the wash phase is concerned, the solution of the present invention improves the mechanical action on laundry and allows an adaptation of the lifter shape to the actual load size.
As far as spinning phase is concerned, the solution according to the invention improves gentleness, reduces unbalance and supports laundry distribution between spinning steps.
In the last step of the washing/spinning cycle (i.e. tumbling after spinning), the lifter according to the invention reduces tangling/wrinkling and makes easier unloading of all loads removed from drum wrapper.
Further features and advantages of a washing machine according to the present invention will be clear from the detailed description of one example thereof, with reference to the attached drawing in which:

figure 1 is a perspective view of a drum of a front loading washing machine according to the present invention;
figure 2 is an enlarged front view of a component of the drum of figure 1;
figure 3 is a section taken along line III-III of figure 2; and
figure 4 is a cross section front view of a drum of a washing machine of figure 1.

With reference to the drawings, a rotating drum 10 of a front loading washer is rotatably mounted in a tub (not shown) and it is provided with at least a lifter 12.
The lifter 12 comprises a hollow base portion 12a fastened to the drum 10 and a movable portion 12b hinged along an axis X to the base portion 12a. The movable portion has a convex smooth surface 14 facing the rotating axis of the drum 10. Between the base portion 12a and the movable portion 12b there is a U-shaped spring 16 (figure 3) having a first end 16a acting on the base portion 12a of the lifter 12 and a second end 16b acting on the concave surface of the movable portion 12b. Therefore the movable portion 12b can assume a first extended position shown in solid lines figures 1-4 in which the upper surface 14 of the lifter is inclined with reference to the axis of the rotating drum and a second retracted position (shown in dotted line in figure 3), in which the upper surface 14 of the movable portion 12b is less inclined (or horizontal) than in the first configuration and it is substantially flush with side edges E of the hollow base portion 12a. In order to limit the extension of the movable portion 12b, this latter is provided with a detent 18 cooperating with a corresponding L-shaped edge 20 of the base portion 12a. This embodiment in which the movable portion 12b is hinged to the base portion 12a is only one of the several ways in which there can be a relative movement between these two components. For instance the movable portion 12b can slide inside the base portion 12a thanks to telescopic coupling. In this second embodiment (not shown in the drawings), compression springs are used instead of a U-shaped spring.
According to a third embodiment (not shown), the base portion 12a, instead of being fastened to the drum 10, can be obtained integral with the drum, for instance by providing hollow seats in the drum metal wrapper.
In the normal washing condition (shown in the figures), the force of the spring 16 is sufficient to keep the movable portion 12b of the lifter 12 in its extended position, therefore assuring the best efficiency in washing performances by lifting laundry during tumbling. In the spinning condition (shown in dotted line in figure 3), the centrifugal force acting on the movable portions 12b and/or on the laundry is sufficient to lower the movable portion 12b of each lifter, therefore assuring a smoother and flatter configuration of the laundry with advantages in term of better balance during spinning. Of course the mass of each movable portion 12b can be chosen so that it can assume a retracted position in the tumbling phase, depending either on the rotating speed of the drum 10 or on the actual laundry load in the drum.
Even if the above embodiments are focused on a washing machine, the lifter according to the invention may be used in the drum of a dryer as well.

Claims

Washing or drying machine comprising a rotating drum (10) and at least a lifter (12) arranged on an inner peripheral surface of the drum (10), characterized in that the lifter (12) is movable.
Washing or drying machine according to claim 1, wherein the lifter (12) comprises a base portion (12a) and a movable portion (12b) supported by the base portion (12a).
Washing or drying machine according to claim 2, wherein the base portion (12a) is integral with the drum (10).
Washing or drying machine according to claim 2, wherein the base portion (12a) is fastened to the drum (10).
Washing or drying machine according to any of claims 2-4, wherein between the base portion (12a) and the movable portion (12b) spring means (16, 16a, 16b) are interposed in order to elastically urge the movable portion (12b) towards an extended position.
Washing or drying machine according to any of claims 2-5, wherein the movable portion (12b) is hinged to the base portion (12a) so that in the extended position the upper surface (14) of the lifter (12, 12b) is inclined.
Washing or drying machine according to any of claims 2-6, wherein the mass of the movable portion (12b) is predetermined so that it can move to a retracted position when the rotating speed is higher than a set value.