Method for determining the load in a washing machine

1. A method for simple and precise determining the load in a washing machine, comprising the steps of:

a. providing a washing machine ( 1 ), with

i. a washing machine casing ( 7 ) and a washing unit ( 2 ),

ii. at least one suspension element ( 6 ) for the oscillatory fastening of the washing unit ( 2 ) on the washing machine casing ( 7 ), and

iii. at least one damper ( 12 ) having a non-linear damping characteristic for damping the movement of the washing unit ( 2 ), the at least one damper ( 12 ) comprising a casing ( 13 ), a ram ( 15 ) which is displaceable in the casing ( 13 ) and a piston ( 33 ) which is displaceable relative thereto,

b. determining a first measured value (M 1 ) in the unloaded state of the washing machine ( 1 ) by measuring a variable which characterizes the load (B),

c. calculating a first suspension force (FA (M 1 )) of the at least one suspension element ( 6 ) as a function of the first measured value (M 1 ),

d. calculating a first damper force (FD (M 1 )) of the at least one damper ( 12 ) as a function of the first measured value (M 1 ),

e. determining a second measured value (M 2 ) in the loaded state of the washing machine ( 1 ) by measuring the variable which characterizes the load (B),

f. calculating a second suspension force (FA (M 2 )) of the at least one suspension element ( 6 ) as a function of the second measured value (M 2 ),

g. calculating a second damper force (FD (M 2 )) of the at least one damper ( 12 ) as a function of the second measured value (M 2 ), and

h. calculating the load (B) of the washing machine ( 1 ) as a function of the suspension forces (FA (M 1 ), FA (M 2 )) and the damper forces (FD (M 1 ), FD (M 2 )).

2. A method according to claim 1 , wherein the variable which characterizes the load (B) is a damper length (L) of the at least one damper ( 12 ).

3. A method according to claim 1 , wherein a respective washing unit position (xA (M 1 ), xA (M 2 )) of the washing unit ( 2 ) is calculated as a function of the measured values (M 1 , M 2 ).

4. A method according to claim 1 , wherein the variable which characterizes the load (B) is a washing unit position (xA) of the washing unit ( 2 ).

5. A method according to claim 1 , wherein a respective damper length (L (M 1 ), L (M 2 )) of the at least one damper ( 12 ) is calculated as a function of the measured values (M 1 , M 2 ).

6. A method according to claim 1 , wherein the first damper force (FD (M 1 )) is calculated by equating with the negative first suspension force (FA (M 1 )).

7. A method according to claim 1 , wherein a first piston position (xK (M 1 )) of the piston ( 33 ) is calculated as a function of the first suspension force (FA (M 1 )) or the first damper force (FD (M 1 )).

8. A method according to claim 7 , wherein the first piston position (xK (M 1 )) is calculated as a function of a damper characteristic (FD (xK)) of the at least one damper ( 12 ).

9. A method for simple and precise determining the load in a washing machine, comprising the steps of:

a. providing a washing machine ( 1 ), with

i. a washing machine casing ( 7 ) and a washing unit ( 2 ),

ii. at least one suspension element ( 6 ) for the oscillatory fastening of the washing unit ( 2 ) on the washing machine casing ( 7 ), and

iii. at least one damper ( 12 ) with a non-linear characteristic for damping the movement of the washing unit ( 2 ), the at least one damper ( 12 ) comprising a casing ( 13 ), a ram ( 15 ) which is displaceable in the casing ( 13 ) and a piston ( 33 ) which is displaceable relative thereto,

b. determining a first measured value (M 1 ) in the unloaded state of the washing machine ( 1 ) by measuring a variable which characterizes the load (B),

c. calculating a first suspension force (FA (M 1 )) of the at least one suspension element ( 6 ) as a function of the first measured value (M 1 ),

d. calculating a first damper force (FD (M 1 )) of the at least one damper ( 12 ) as a function of the first measured value (M 1 ),

e. determining a second measured value (M 2 ) in the loaded state of the washing machine ( 1 ) by measuring the variable which characterizes the load (B),

f. calculating a second suspension force (FA (M 2 )) of the at least one suspension element ( 6 ) as a function of the second measured value (M 2 ),

g. calculating a second damper force (FD (M 2 )) of the at least one damper ( 12 ) as a function of the second measured value (M 2 ), and

h. calculating the load (B) of the washing machine ( 1 ) as a function of the suspension forces (FA (M 1 ), FA (M 2 )) and the damper forces (FD (M 1 ), FD (M 2 )),

i. wherein the second damper force (F D (M 2 )) is calculated as a function of a second piston position (x K (M 2 )) of the piston ( 33 ) and a damper characteristic (F D (x K )) of the at least one damper ( 12 ) having a non-linear damping characteristic.

10. A method for simple and precise determining the load in a washing machine, comprising the steps of:

a. providing a washing machine ( 1 ), with

i. a washing machine casing ( 7 ) and a washing unit ( 2 ),

ii. at least one suspension element ( 6 ) for the oscillatory fastening of the washing unit ( 2 ) on the washing machine casing ( 7 ), and

iii. at least one damper ( 12 ) with a non-linear characteristic for damping the movement of the washing unit ( 2 ), the at least one damper ( 12 ) comprising a casing ( 13 ), a ram ( 15 ) which is displaceable in the casing ( 13 ) and a piston ( 33 ) which is displaceable relative thereto,

b. determining a first measured value (M 1 ) in the unloaded state of the washing machine ( 1 ) by measuring a variable which characterizes the load (B),

c. calculating a first suspension force (FA (M 1 )) of the at least one suspension element ( 6 ) as a function of the first measured value (M 1 ),

d. calculating a first damper force (FD (M 1 )) of the at least one damper ( 12 ) as a function of the first measured value (M 1 ),

e. enquiring the calculated first damper force (FD (M 1 )) with an interrogation element ( 53 ),

f. distinguishing whether the calculated first damper force (FD (M 1 )) is smaller than, equal to or bigger than zero with the interrogation element ( 53 ),

g. presenting the first damper force (FD (M 1 )) to a calculating element ( 54 ; 55 ; 56 ) depending on the value of the calculated first damper force (FD (M 1 )),

h. determining a second measured value (M 2 ) in the loaded state of the washing machine ( 1 ) by measuring the variable which characterizes the load (B),

i. calculating a second suspension force (FA (M 2 )) of the at least one suspension element ( 6 ) as a function of the second measured value (M 2 ),

j. calculating a second damper force (FD (M 2 )) of the at least one damper ( 12 ) as a function of the second measured value (M 2 ), and

k. calculating the load (B) of the washing machine ( 1 ) as a function of the suspension forces (FA (M 1 ), FA (M 2 )) and the damper forces (FD (M 1 ), FD (M 2 )).

11. A method for determining the load in a washing machine, comprising the steps of:

a. providing a washing machine ( 1 ), with

i. a washing machine casing ( 7 ) and a washing unit ( 2 ),

ii. at least one suspension element ( 6 ) for the oscillatory fastening of the washing unit ( 2 ) on the washing machine casing ( 7 ), and

iii. at least one damper ( 12 ) having a non-linear damping characteristic for damping the movement of the washing unit ( 2 ), the at least one damper ( 12 ) comprising a casing ( 13 ), a ram ( 15 ) which is displaceable in the casing ( 13 ) and a piston ( 33 ) which is displaceable relative thereto,

b. determining a first measured value (M 1 ) in the unloaded state of the washing machine ( 1 ) by measuring a variable which characterises the load (B),

c. calculating a first suspension force (FA (M 1 )) of the at least one suspension element ( 6 ) as a function of the first measured value (M 1 ),

d. calculating a first damper force (FD (M 1 )) of the at least one damper ( 12 ) as a function of the first measured value (M 1 ),

e. determining a second measured value (M 2 ) in the loaded state of the washing machine ( 1 ) by measuring the variable which characterises the load (B),

f. calculating a second suspension force (FA (M 2 )) of the at least one suspension element ( 6 ) as a function of the second measured value (M 2 ),

g. calculating a second damper force (ED (M 2 )) of the at least one damper ( 12 ) as a function of the second measured value (M 2 ), and

h. calculating the load (B) of the washing machine ( 1 ) as a function of the suspension forces (FA (M 1 ), FA (M 2 )) and the damper forces (ED (M 1 ), ED (M 2 )),

i. wherein the sum of the difference between the suspension forces (Δ FA) and the difference between the damper forces (ΔFD) is formed for calculating the load (B).

12. A method according to claim 11 , wherein the load (B) is reliably detected with the at least one damper ( 12 ) having a non-linear characteristic.

13. A method according to claim 10 , wherein the first damper force (F D (M 1 )) is presented to the calculating element ( 54 ), if the first damper force (F D (M 1 )) is smaller than zero.

14. A method of claim 13 , wherein a first piston position (x K (M 1 )) is calculated using the calculating element ( 54 ), wherein said calculation is carried out using a damper characteristic (F D (x K )), which describes the relationship between the piston position (x K ) and the damper force (F D ).

15. A method of claim 14 , wherein the damper characteristic (F D (x K )) is stored in the calculating element ( 54 ).

16. A method of claim 15 , wherein the first piston position (x K (M 1 )) is calculated by evaluating the damper characteristic (F D (x K )) in the place of the first damper force (F D (M 1 )).

17. A method of claim 16 , wherein the damper characteristic (F D (x K )) of the at least one damper ( 12 ) is determined in advance.

18. A method of claim 10 , wherein the first damper force (F D (M 1 )) is presented to the calculating element ( 55 ), if the first damper force (F D (M 1 )) is equal to zero.

19. A method of claim 18 , wherein the first piston position (x K (M 1 )) is assumed to be a starting value of the piston position (x K (0)).

20. A method of claim 10 , wherein the first damper force (F D (M 1 )) is presented to the calculating element ( 56 ), if the first damper force (F D (M 1 )) is greater than zero.

21. A method of claim 20 , wherein a first piston position (x K (M 1 )) is calculated using the calculating element ( 56 ), wherein said calculation is carried out using a damper characteristic (F D (x K )), which describes the relationship between the piston position (x K ) and the damper force (F D ).