Textiles: fluid treating apparatus – Machines – Single tub and automatic sequential operation mechanism
Patent
1991-01-03
1992-11-24
Stinson, Frankie L.
Textiles: fluid treating apparatus
Machines
Single tub and automatic sequential operation mechanism
68 1206, D06F 3302
Patent
active
051652609
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a machine for the treatment of laundry, such as a dryer or washing-machine.
A known washing-machine of this kind (DE-PS 30 25 088) has the drum supported for rotation in the lye tank, while the lye tank is supported in a suitable manner on the bottom of the housing, via resilient and, in certain cases, damping supports. The drum is supported in the lye tank in the usual manner, namely in unilaterally overhung arrangement, by means of a star-shaped mounting bracket fastened undetachably to the back of the lye tank by means of a plurality of screws and fishplates. The arms of the star-shaped mounting bracket extend right to the peripheral areas of the lye tank, and may even reach around the latter, for improved solidity, as the drum, being heavily loaded with wet laundry in the operating condition of the machine, has a pronounced tendency to tilt in the hub area of the star-shaped mounting bracket where it is held by only one double bearing.
In order to provide such a mechanical arrangement with a suitable measuring system which on the one hand permits the increasing weight caused by the laundry being filled in to be recorded and evaluated automatically and which on the other hand operates with sufficient accuracy, electromechanical transducers are arranged on those parts of the star-shaped mounting brackets which are exposed to particularly pronounced stresses under the effect of the drum weight. The weight-proportional output signals supplied by these electromagnetic transducers, for example resistance strain gauges or piezoelectric transducers mounted firmly in the material of the star-shaped mounting bracket, are then transmitted to a signal-processing arrangement which is thereby enabled, for example, to evaluate the weight of the laundry filled in and to derive therefrom automatically the liquid level in the lye tank and to adapt it as required.
This publication (DE-PS 30 25 088) clearly recognizes, and explains with reference to other publications likewise dealing with the problem of recording the weight of laundry (U.S. Pat. No. 2,412,270; DE-AS 11 57 578; DE-OS 20 34 847) that sufficient accuracy, initially only with respect to the weight of the laundry, can be achieved only under certain particular conditions. The problems connected with the determination of the weight have been seen heretofore in the fact that, regardless of the type of measuring sensor used, the dead weight of the washing machine (for example 100 Kg) makes it impossible for the usual increase in weight resulting from the dry laundry (approx. 0.5 to 5 Kg) to cause effects important enough for being determined with sufficient accuracy for use in an automatic control circuit.
In setting out this theory, DE-PS 30 25 088 disregards, however, at least in part the main reason for the measuring inaccuracies namely that all measuring processes previously employed are affected by excessive frictional influences so that these, and the hysteresis produced by such frictional influences, are already sufficient reason that no exact results can be expected for the desired weight measurements. While such accuracies are already critical in determining the weight of the laundry, and the water level to be derived therefrom, they make such measurements absolutely useless if one tries to determine automatically the quantity of detergents to be added, including the quantities of fabric softeners, special detergents, and so on, and to use for this purpose automatic control circuits, including in particular minicomputers and microprocessors with corresponding storage capacities, and the like, which are currently in use today, and this although such program-controlled operation would be so very important today, especially under the aspects of environmental protection.
The same is true for the solution proposed by DE-PS 30 25 088 which does not itself even expect a better accuracy than a resolution of approx. 0.1 Kg (column 3, line 4, of the quoted patent specification).
However, such measuring
REFERENCES:
patent: 3013421 (1961-12-01), Buss
patent: 3088593 (1963-05-01), Stilwell, Jr.
patent: 4159211 (1979-06-01), Hoffman
patent: 4663948 (1987-05-01), Rummel
BSG-Schalttechnik GmbH & Co. KG
Stinson Frankie L.
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