Control method of a laundry machine

Abstract

A laundry machine and a control method thereof are provided in which laundering ability may be improved while also improving efficiency and noise/vibration. The laundry machine employs a plurality of drum motions by varying drum rotational speed, drum rotational direction, and drum starting and stopping point, to provide different motion of laundry items in the drum.

1 . A method of operating a laundry machine having a drum with an axis of rotation through a center of the drum, the method comprising rotating the drum in a first motion, comprising:
 rotating the drum at a first predetermined rotational speed such that a reference point on the drum, initially positioned at an initial position, rotates about the axis of rotation, wherein the reference point is any point on a side of the drum;   changing the rotational speed of the drum when the reference point has traveled a first predetermined distance about the axis of rotation of the drum;   resuming rotation of the drum at a second predetermined rotational speed; and   changing the rotational speed of the drum when the reference point has traveled a second predetermined distance about the axis of rotation of the drum, such that the reference point of the drum has returned to a position substantially at the initial position.   
     
     
         2 . The method of  claim 1 , wherein the first and second predetermined rotational speeds are substantially equal, and the first and second predetermined distances are substantially equal. 
     
     
         3 . The method of  claim 1 , wherein the first and second predetermined distances together equal approximately 360 degrees about the axis of rotation of the drum. 
     
     
         4 . The method of  claim 1 , wherein changing the rotational speed of the drum comprises decreasing the rotational speed of the drum for a predetermined period of time. 
     
     
         5 . The method of  claim 1 , wherein changing the rotational speed of the drum comprises pausing the rotation of the drum for a predetermined period of time. 
     
     
         6 . The method of  claim 1 , wherein changing the rotational speed of the drum comprises applying a reverse torque in a direction opposite to the rotation direction of the drum so as to suddenly stop the drum. 
     
     
         7 . The method of  claim 1 , further comprising rotating the drum in a second motion, comprising:
 rotating the drum at a third predetermined rotational speed that is less than the first and second predetermined rotational speeds.   
     
     
         8 . The method of  claim 7 , further comprising rotating the drum in a third motion, comprising rotating the drum at a fourth predetermined rotational speed that is less than the first and second predetermined rotational speeds and greater than the third predetermined rotational speed. 
     
     
         9 . The method of  claim 1 , further comprising rotating the drum in a second motion, comprising:
 rotating the drum in a first direction at a third predetermined rotational speed;   changing the rotational speed of the drum when the reference point has traveled a third predetermined distance about the axis of rotation of the drum;   resuming rotation of the drum in a second direction, that is opposite the first direction, at a fourth predetermined rotational speed such that the reference point of the drum passes through the initial position; and   changing the rotational speed of the drum again when the reference point has traveled a fourth predetermined distance about the axis of rotation of the drum.   
     
     
         10 . The method of  claim 9 , wherein the first and second predetermined rotational speeds are substantially equal to each other, and the third and fourth predetermined rotational speeds are substantially equal to each other, and wherein first and second predetermined rotational speeds are greater than the third and fourth predetermined rotational speeds. 
     
     
         11 . The method of  claim 1 , further comprising rotating the drum in a second motion, comprising:
 rotating the drum at a third predetermined rotational speed such that a first centrifugal force generated by the rotation of the drum causes a laundry item positioned in the drum to cling to an inner surface of the drum;   rotating the drum at a fourth predetermined rotational speed such that a second centrifugal force generated by the rotation of the drum speed is insufficient for the laundry item to cling to the inner surface of the drum; and   resuming rotation of the drum at the third predetermined rotational speed such that the laundry is drawn back toward the inner surface of the drum and clings to the inner surface of the drum.   
     
     
         12 . A method of operating a laundry machine having a drum with an axis of rotation through a center of the drum, the method comprising rotating the drum in a first motion, comprising:
 (a) rotating the drum in a first direction at a first predetermined rotational speed such that a reference point on the drum, initially positioned at an initial position, rotates about the axis of rotation to a first predetermined position, wherein the reference point is any point on a side of the drum;   (b) when the reference point has reached the first predetermined position, changing the direction of rotation of the drum and rotating the drum in a second direction opposite the first direction at the first predetermined rotational speed such that the reference point of the drum travels back through the initial position toward a second predetermined position;   (c) when the reference point has reached the second predetermined position, changing the direction of rotation of the drum and rotating the drum in the first direction such that the reference point travels back toward the initial position; and   (d) applying any one or more of the following during at least one of the step (a), step (b) or step (c):   (i) a rotational speed of the drum in the first and second directions is greater than 45 RPMs; or   (ii) the reference point of the drum is greater than an absolute value of 90 degrees from the initial position at the first and second predetermined positions; or   (iii) changing direction of rotation of the drum comprises braking a motor that drives the drum or changing a rotation direction of the motor to apply a reverse torque to the drum.   
     
     
         13 . The method of  claim 12 , wherein rotating the drum in a first direction and rotating the drum in a second direction comprises driving a motor coupled to the drum so as to provide rotational forces from the motor in the first and second directions, respectively, and rotating the drum in the first and second directions at rotational speeds that are greater than a reference rotational speed. 
     
     
         14 . The method of  claim 13 , wherein changing the direction of rotation of the drum comprises applying a braking force to the motor when the reference point reaches the first and second predetermined positions, and rotating the motor in an opposite direction so as to change the direction of rotation of the drum. 
     
     
         15 . The method of  claim 12 , wherein, at the first and second predetermined positions, the reference point of the drum is greater than 90 degrees from the initial position and less than 180 degrees from the initial position. 
     
     
         16 . The method of  claim 15 , wherein, at the first and second predetermined positions, the reference point of the drum is greater than 120 degrees from the initial position. 
     
     
         17 . The method of  claim 12 , further comprising rotating the drum in a second motion, comprising:
 rotating the drum in either the first direction or the second direction at a second predetermined rotational speed that is less than the first predetermined rotational speed.   
     
     
         18 . The method of  claim 17 , further comprising rotating the drum in a third motion, comprising rotating the drum in either the first direction or the second direction at a third predetermined rotational speed that is less than the first predetermined rotational speed and greater than the second predetermined rotational speed. 
     
     
         19 . The method of  claim 12 , further comprising rotating the drum in a second motion, comprising:
 rotating the drum in the first direction at a second predetermined rotational speed that is less than the first predetermined rotational speed such that the reference point rotates about the axis of rotation to a third predetermined position that is closer to the initial position than the first predetermined position is;   when the reference point has reached the third predetermined position, changing the direction of rotation of the drum and rotating the drum in the second direction at the second predetermined rotational speed such that the reference point of the drum travels back through the initial position toward a fourth predetermined position, wherein the fourth predetermined position is closer to the initial position than the second predetermined position is; and   when the reference point has reached the fourth predetermined position, changing the direction of rotation of the drum and rotating the drum in the first direction again such that the reference point travels back toward the initial position.   
     
     
         20 . The method of  claim 12 , further comprising rotating the drum in a second motion, comprising:
 rotating the drum at a first predetermined rotational speed such that a first centrifugal force generated by the rotation of the drum causes a laundry item positioned in the drum to cling to an inner surface of the drum;   rotating the drum at a second predetermined rotational speed such that a second centrifugal force generated by the rotation of the drum is insufficient for the laundry item to cling to the inner surface of the drum; and   resuming rotation of the drum at the first predetermined rotational speed such that the laundry is drawn back toward the inner surface of the drum and clings to the inner surface of the drum.   
     
     
         21 . A method of operating a laundry machine having a drum with an axis of rotation through a center of the drum, the method comprising rotating the drum in a first motion, comprising:
 rotating the drum at a first predetermined rotational speed such that a first centrifugal force generated by the rotation of the drum at the first predetermined rotational speed causes a laundry item positioned in the drum to cling to an inner surface of the drum as the drum rotates at the first predetermined rotational speed;   rotating the drum at a second predetermined rotational speed such that a second centrifugal force generated by the rotation of the drum at the second predetermined rotational speed is insufficient for the laundry item to cling to the inner surface of the drum as the drum rotates at the second predetermined rotational speed; and   rotating the drum at a third predetermined rotational speed such that a third centrifugal force generated by the rotation of the drum at the third rotational speed causes the laundry item to be drawn back to the inner surface of the drum and cling to the inner surface of the drum as the drum rotates at the third predetermined rotational speed.   
     
     
         22 . The method of  claim 21 , wherein the first predetermined rotational speed is substantially equal to the third predetermined rotational speed, and the second predetermined rotational speed is less than the first predetermined rotational speed and the third predetermined rotational speed. 
     
     
         23 . The method of  claim 21 , wherein the first predetermined rotational speed and the third predetermined rotational speed are approximately 60 RPM, and the second predetermined rotational speed is less than 60 RPM. 
     
     
         24 . The method of  claim 21 , further comprising rotating the drum in a second motion, comprising:
 rotating the drum at a third predetermined rotational speed that is less than the first and second predetermined rotational speeds.   
     
     
         25 . The method of  claim 24 , further comprising rotating the drum in a third motion, comprising rotating the drum a fourth predetermined rotational speed that is less than the first and second predetermined rotational speeds and greater than the third predetermined rotational speed. 
     
     
         26 . The method of  claim 21 , further comprising rotating the drum in a second motion, comprising:
 rotating the drum in a first direction at a third predetermined rotational speed that is less than the first and second predetermined rotational speeds such that a reference point on an outside of the drum travels from an initial position toward a first predetermined position;   when the reference point has reached the first predetermined position, changing the direction of rotation of the drum and rotating the drum in a second direction at the third predetermined rotational speed such that the reference point of the drum travels back through the initial position toward a second predetermined position; and   when the reference point has reached the second predetermined position, changing the direction of rotation of the drum and rotating the drum in the first direction again such that the reference point travels back toward the initial position.