Cloth amount detector in washing machine

Abstract: A cloth amount detecting device in a washing machine including a process controller for controlling a process of washing, rinsing and spin-drying cloths put into the washing machine is designed to detect the amount of the cloths. If the user of the washing machine changes the level of water within the washing machine to a different water level after the amount of cloths has been detected, a reference value used to determine the amount of cloths is updated by learning in dependence on the water level so changed by the user and the number of waveforms of a drive motor, thereby to accomplish a determination faithful to the amount of cloths.

Description: The present invention relates to a clothes amount detecting device in a washing machine which comprises a detecting means for outputting a clothes signal representative of the amount of clothes put into the washing machine; a determining means operable to receive the clothes signal and for comparing the received clothes signal with a reference value thereby to determine the amount of the clothes; and a selector means operable by a user of the washing machine for changing the reference value to a different reference value. A washing machine containing such a detecting device for detecting the amount of clothes is known from EP-A-252 817. In recent years the use of automated washing machines has gained wide acceptance, and most sophisticated washing machines make use of a clothes amount detecting device to permit the washing machine to provide an optimum water current and a process control scheme that are appropriate to the amount of clothes put into a washtub or basket and detected thereby. An example of the use of the clothes amount detecting device in the washing machine is disclosed in, for example, JP-A-1-119290, published May 11, 1989. According to this publication, the clothes amount detecting device in an automated washing machine comprising a drive motor for driving a current inducing element such as, for example, a pulsator or an agitator, includes an electromotive force detecting means. Specifically, the drive motor is switched on for a predetermined length of time after water has been filled in the washtub to a predetermined level, and is subsequently switched off. The electromotive force detecting means detects an electromotive force generated by the drive motor during an OFF period in which the drive motor is switched off subsequent to the ON period, that is, the predetermined length of time during which it has been switched on. The cloth amount detecting device also includes a determining means for determining the amount of clothes, put into the washtub for washing, in dependence on an output from the electromotive force detecting means. It has, however, been found that the prior art clothes amount detecting device of the type referred to above has a problem which will now be discussed. In the system of the prior art clothes amount detecting device, since a reference clothes value utilized to compare with the actual amount of clothes to be washed is fixed to a predetermined clothes value, it often occurs that the reference clothes value does not match with the amount of clothes which the user of the washing machine has believed it ought to be, or with the amount of the clothes determined by the determining means due to a change in tension or an aging of a drive belt which is used to transmit a drive from the drive motor to the current inducing element. The present invention has been devised with a view to substantially eliminating the above discussed problems inherent in the prior art cloth amount detecting device in the automated washing machine and is intended to provide an improved clothes amount detecting device wherein the reference value used in determining the amount of clothes to be washed varies generally in consistence with the user's intention as to the amount of clothes he or she has put into the washtub. According to the invention, a clothes amount detecting device as defined in the preamble of claim 1 is characterized in that said determining means is adapted to store the changed reference value which has been selected by the selector means and, during the next succeeding determination of the amount of clothes, to determine the amount of clothes using the changed selected reference value which has been selected. Preferable embodiments are defined in the dependent claims. To this end, the cloth amount detecting device in the automated washing machine according to the present invention includes a process control means for controlling a washing process executed by the washing machine, a drive motor installed for driving a current inducing element installed inside a washtub, a drive detecting means for detecting the number of revolutions of the drive motor, a water level setting means for setting a level of water inside the washtub, and a determining means operable in response to an output from the drive detecting means for determining the amount of cloths put into the washtub, said determining means having a reference value for the determination of the amount of the clothes which is variable with a setting data of the water level setting means. According to the present invention, the reference value for the determination of the amount of the clothes to be washed undergoes a learning on the basis of the water level data furnished by the water level setting means and is therefore modified so as to be generally consistent with the user's intention. Thus, any possibility that the reference value does not match with the amount of the clothes actually determined can advantageously be eliminated. As discussed above, the clothes amount detecting device in the automated washing machine according to the present invention includes a process control means for controlling a washing process performed by the washing machine, a drive motor installed for driving a current inducing element installed inside a washtub, a drive detecting means for detecting the number of revolutions of the drive motor, a water level setting means for setting a level of water inside the washtub, and a determining means operable in response to an output from the drive detecting means for determining the amount of clothes put into the washtub. The determining means undergoes a learning repeatedly in reference to clothes data provided by the water level setting means thereby to update the reference value to be used for the determination of the amount of the clothes. Therefore, the clothes amount detecting device can be realized in which there is neither the possibility that the reference value for the determination of the amount of the clothes may depart from the user's intention as to the amount of the clothes, not the possibility that the reference value may not match with the amount of the clothes determined by the determining means due to a change in tension or an aging of the drive belt used to transmit the drive from the drive motor to the current inducing element. This and other objects and features of the present invention will become clear from the following description taken in conjunction with a preferred embodiment thereof with reference to the accompanying drawings, in which like parts are designated by like reference numerals and in which: Fig. 1 is a schematic side sectional view of an automated washing machine incorporating a clothes amount detecting device according to the present invention; Fig. 2 is a schematic plan view of a selector means used in the clothes amount detecting device; Fig. 3 is a graph showing a relationship between waveforms outputted from a voltage detecting means and the amount of clothes to be washed; and Fig. 4 is a graph showing a different relationship between the waveforms outputted from the voltage detecting means and the amount of clothes to be washed. An automated washing machine shown in Fig. 1 for the purpose of illustrating the present invention is a combined washer and spin-dryer of top loading model. The automated washing machine includes a hold 2 opening upwardly and closed at its bottom, a generally cylindrical perforated washtub 1 accommodated within the hold 2 in a coaxial relationship therewith. A current inducing element, for example, a disc-shaped pulsator 3 is installed at the bottom of the washtub 1 and is drivingly coupled with a drive motor 5 through a speed reduction unit 4 installed exteriorly beneath the bottom of the hold 2. The bottom of the hold 2 is fluid-connected to the outside of the washing machine through an electromagnetically controlled drain valve 6, whereas an electromagnetically controlled supply valve 7 is installed on a water supply line extending above the washtub 1. In any event, the washing machine of a construction so far described is well known and, therefore, the details thereof will not be herein discussed. An electric control system employed in the washing machine includes a process control means 8, a selector means 9, a water level detecting means 10, a voltage detecting means 11 and a clothes determining means 12. The process control means 8 receives outputs generated from the selector means 9 and the water level detecting means 10 and sequentially controls the drive motor 5, the drain valve 6 and the supply valve 7 so that a process of washing, rinsing and spin-drying can be executed in a predetermined sequence. The voltage detecting means 11 is electrically connected with the drive motor 5 to detect a motor voltage which is one of physical parameters correlated with the number of revolutions of the drive motor 5. This voltage detecting means 11 has the function of a clothes amount detecting device and feeds its output to the determining means 12 so that the latter can counts the number of voltage waveforms generated by the voltage detecting means 11 and then compare the count value with a reference value. Fig. 2 illustrates the selector means 9 which includes a water level setting means 9a, a water current setting means 9b, a washing setting means 9c, a rinsing setting means 9d and a spin-drying setting means 9e. The clothes amount detecting device of the above described construction operates in the following manner. When the washing machine is run after contents of the process have been selected and set by means of the selector means 9, the process control means 8 receives from the water level detecting means 10 information concerning the level of water within the washtub and causes the supply valve 7 to open so that water can be supplied into the hold 2 to a predetermined level. Then, the process control means 8 energizes the drive motor 5 to drive the pulsator 3. The supply of an electric power to the drive motor 5 is interrupted after a predetermined length of time subsequent to the start of rotation of the drive motor 5, causing the voltage detecting means 11 to supply to the determining means 12 a signal indicative of the number of waveforms detected by the voltage detecting means 11 and also to compare the count with a predetermined value thereby to determine the amount of clothes to be washed that are put into the washtub 1. The manner in which the amount of the clothes to be washed is determined by the determining means 12 will now be described in detail. Referring to the graph of Fig. 3 showing a relationship between the amount of clothes put into the washtub 1 for washing and waveforms generated by the voltage detecting means 11, threshold values P 1 , P 2 and P 3 are utilized as respective reference values. In the illustrated instance, the use of these three reference values represents four amount zones each indicative of a range of amount of cloths put into the washtub 1, namely, a "MAXIMUM" amount, a "MEDIUM" amount, a "SMALL" amount and an "EXTREMELY SMALL" amount. These reference values could be determined empirically by a correlation between the amount of clothes to be washed and the number of the output waveforms of the voltage detecting means 11. However, when the user of the washing machine feels that the amount of clothes determined by the determining means 12 is obviously improper or objectionable, for example, when the user of the washing machine feels that the water level detected by the water level detecting means 10 is obviously low for that amount of clothes under the situation in which the determining means 12 has determined that the amount of the clothes put into the washtub 1 was "MEDIUM" and, hence, the water level to which water should have been supplied into the hold 2 was determined a "medium" level for that medium amount of the clothes, the user of the washing machine can change the preset water level to a "high" level by manipulating the water level setting means 9a. The process control means 8 then performs the sequence of controls using the preset "high" water level and, at the same time, the determining means 12 changes one of the reference values to another one of the reference values in dependence on the number of the output waveforms, then generated by the voltage detecting means 11, and the amount of the clothes appropriate to the water level changed by the user of the washing machine. One embodiment of how the reference value is changed will now be discussed in detail. Assuming that the output waveform generated by the voltage detecting means 11 at the time the amount of clothes in the washtub 1 is to be determined is such a value as indicated by Px in Fig. 3, the determining means 12 determines that the amount of the clothes put into the washtub 1 falls within the "MEDIUM" amount and the process control means 8 sets the water level within the hold 2 to a medium level. When under this situation the user of the washing machine manipulates the water level setting means 9a to set the water level to a high level by the reason that he or she had considered that the medium level of water is insufficient for the actual amount of the clothes, the determining means 12 responding to the change in water level setting adds a predetermined number of waveforms ΔPa to each of the reference values P 1 , P 2 and P 3 thereby to shift the respective reference value to a higher value as shown by the following equations. P 1(M + 1) = P 1(M) + ΔPa P 2(M + 1) = P 2(M) + ΔPa P 3(M + 1) = P 3(M) + ΔPa These shifted reference values are utilized subsequently for the determination of the amount of clothes put into the washtub 1. Thus, consequent on the change of the reference values, the amount of clothes determined by the determining means 12 increases. On the other hand, in the case of the situation substantially reverse to that discussed above, that is, when the user of the washing machine manipulates the water level setting means 9a to set the water level within the hold 2 to a medium level under the situation in which the determining means 12 has determined that the amount of clothes put into the washtub 1 was "MAXIMUM" and, hence, the process control means 8 has set the water level within the hold 2 to a "high" level, the determining means 12 responds to the change in water level setting in such a way as to subtract a predetermined number of waveforms ΔPa from each of the reference values P 1 , P 2 and P 3 thereby to shift the respective reference value to a lower value as shown by the following equations. P 1(M + 1) = P 1(M) - ΔPa P 2(M + 1) = P 2(M) - ΔPa P 3(M + 1) = P 3(M) - ΔPa Thus, the change of the reference values used for the determination of the amount of clothes put into the washtub permits a clothes amount determining level of the determining means 12 to follow the setting made by the user of the washing machine. It is to be noted that the amount of change of each reference values is restricted to the amount not exceeding a predetermined value from the initial value thereof. Another embodiment of how the reference value is changed will now be discussed in detail. Assuming that the output waveform generated by the voltage detecting means 11 at the time the amount of clothes in the washtub 1 is to be determined is such a value as indicated by Px in Fig. 4 as is the case with the foregoing example, the determining means 12 determines that the amount of the clothes put into the washtub 1 falls within the "MEDIUM" amount and the process control means 8 sets the water level within the hold 2 to a medium level. When under this situation the user of the washing machine manipulates the water level setting means 9a to set the water level to a high level by the reason that he or she had considered that the medium level of water is insufficient for the actual amount of the clothes, the water level falling within an allowance for the "MEDIUM" level in which the number of the waveforms Px is included is changed by the reference value P 1 , which corresponds to the selected high water level, in proportion to the difference between the number Px of the waveforms then inputted and the reference value P 1 as shown by the following equation, thereby allowing the reference value to be increased. P 1(M + 1) = P 1(M) + {Px - P 1(M) }/2 This shifted reference value is utilized subsequently for the determination of the amount of clothes put into the washtub 1. Thus, consequent on the change of the reference value, the range within which the amount of clothes to be washed are determined great expands and, therefore, the amount of the clothes to be washed comes to have a tendency of being determined great as compared with that rendered during the previous determination. Where consequent on the change of the reference value the range (for example, the region between P 1 and P 2 ) within which the amount of clothes to be washed is determined is narrowed, the width of this range is restricted to a value greater than a predetermined value Pw and no change of the reference value occur exceeding this limit. Thus, since consequent on this change of the reference value the clothes amount determining level of the determining means 12 sequentially updated individually for each rank of the amount of clothes according to the determination made by the user of the washing machine, the reference value used for the determination of the amount of clothes varies with the actual amount of clothes put into the washtub 1 and, therefore, there is no possibility that the user may effect a correction each time the reference value departs. Although the present invention has fully been described in connection with the various embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. For example, although in the foregoing description of the preferred embodiment of the present invention reference has been made to the use of the determining means 12 of a type wherein, while the use has been made of the voltage detecting means 11 for detecting the motor voltage, the drive motor 5 is driven after the water has been supplied into the hold 2 and then the amount of cloths is determined, any motor speed detecting means as a detecting means for outputting a clothes signal, such as one or more magnets may be employed in place of the voltage detecting means 11. A system wherein the amount of clothes is detected by driving the motor 5 before the water is supplied into the hold 2, or a system wherein a detection is made of a change in level of the water within the hold 2 during agitation, can also be employed in place of the foregoing system, provided that the physical quantity correlated with the amount of clothes put into the washtub 1 can be detected. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims, unless they depart therefrom.

Claims: A clothes amount detecting device in a washing machine which comprises: a detecting means (11) for outputting a clothes signal representative of the amount of clothes put into the washing machine; a determining means (12) operable to receive the clothes signal and for comparing the received clothes signal with a reference value thereby to determine the amount of the clothes; and a selector means (9) operable by a user of the washing machine for changing the reference value to a different reference value; characterized in that said determining means (12) is adapted to store the changed reference value which has been selected by the selector means (9) and, during the next succeeding determination of the amount of clothes, to determine the amount of clothes using the changed selected reference value which has been selected. The device as claimed in Claim 1, wherein said selector means (9) determines the amount of change by which the reference value is to be changed, in dependence on a difference between the reference value, currently used, and a detected clothes amount data represented by the clothes signal outputted from the detecting means (11). The device as claimed in Claim 1, wherein said selector means (9) employs a predetermined value from the reference value, which is currently employed, as an amount of change by which said reference value is to be changed and determines whether said predetermined value should be added to or subtracted from the reference value currently employed. The device as claimed in one of Claims 2 and 3, wherein said determining means (12) has a plurality of reference values in correspondence with respective different amounts of clothes which may be put into the washing machine, said determining means (12) being operable to compare the clothes signal with one of the reference values to determine the amount of the clothes then put into the washing machine, thereby allowing water to be supplied to one of washing and rinsing water levels, and wherein said selector means (9) includes an input unit (9a) for inputting whether the level of water determined and supplied by the determining means (12) is too high for a water level desired by the user or whether the level of water determined and supplied by the determining means (12) is too low for the water level desired by the user, said predetermined value being added to the currently employed reference value in the event that there is an input from the input unit (9a) indicating that the water level is sufficiently high than the water level desired by the user, but subtracted from the currently employed reference value in the event that there is an input from the input unit (9a) indicating that the water level is lower than the water level desired by the user.

Inventors: KIUCHI MITSUYUKI, NAKAMURA TAKERU, TAMAE SADAYUKI, KIUCHI, MITSUYUKI, NAKAMURA, TAKERU, TAMAE, SADAYUKI
Applicants: MATSUSHITA ELECTRIC IND CO LTD, MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Application year: 1992
Main classification: D06F39
IPC codes: D06F39, D06F33