Washing machine and pulsator thereof

Abstract

A Washing machine washes laundry in a wobbling fashion to improve washing force and to prevent damage to the laundry. The washing machine includes a pulsator rotatably mounted at the lower part of a rotary tub to generate a water current and to move laundry, a plurality of lifters protruding from the top of the pulsator to raise the laundry during rotation of the pulsator, and a movement changing member formed at the upper end of each of the lifters to drop the laundry raised by a corresponding one of the lifters. The movement changing member includes a roller rotated by friction with the laundry.

1 . A washing machine comprising:
 a cabinet;   a rotary tub rotatably disposed in the cabinet to contain laundry;   a pulsator rotatably mounted at a lower part of the rotary tub to move the laundry contained in the rotary tub, wherein the pulsator comprises:   valley parts and ridge parts alternately formed in a circumferential direction;   inclined planes formed between the valley parts and the ridge parts; and   a roller mounted at an upper part of each of the ridge parts,   the roller extending from a center of the pulsator in a radial direction to rotate about a radial axis of the pulsator.   
     
     
         2 . The washing machine according to  claim 1 , wherein the roller is formed in the shape of a cylinder having a hollow part. 
     
     
         3 . The washing machine according to  claim 2 , wherein the pulsator further comprises a shaft disposed in the hollow part of the roller to support the roller. 
     
     
         4 . The washing machine according to  claim 1 , wherein the pulsator further comprises a bearing coupled to the roller to smooth rotation of the roller. 
     
     
         5 . The washing machine according to  claim 1 , wherein the pulsator further comprises a receiving space formed at the upper part of each of the ridge parts to receive the roller. 
     
     
         6 . The washing machine according to  claim 5 , wherein the pulsator further comprises a cover to cover a gap defined between the receiving space and the roller to prevent the laundry from being caught in the gap defined between the receiving space and the roller. 
     
     
         7 . The washing machine according to  claim 6 , wherein the cover is integrally formed at the pulsator. 
     
     
         8 . The washing machine according to  claim 1 , wherein the roller is disposed so that a portion of the roller is placed inside each of the ridge parts and the remaining portion of the roller is exposed outside. 
     
     
         9 . The washing machine according to  claim 1 , wherein the inclined planes are curved. 
     
     
         10 . The washing machine according to  claim 1 , wherein the roller is inclined from the center of the pulsator in the radial direction to prevent the laundry from being driven outside due to centrifugal force. 
     
     
         11 . The washing machine according to  claim 1 , wherein the roller is provided at an outer circumference thereof with an accelerating member. 
     
     
         12 . The washing machine according to  claim 11 , wherein the accelerating member comprises a plurality of protrusions formed at the outer circumference of the roller. 
     
     
         13 . The washing machine according to  claim 11 , wherein the accelerating member comprises sawteeth formed at the outer circumference of the roller. 
     
     
         14 . A washing machine comprising:
 a cabinet;   a rotary tub rotatably disposed in the cabinet to contain laundry;   a pulsator rotatably mounted at a lower part of the rotary tub to move the laundry contained in the rotary tub, wherein the pulsator comprises:   valley parts and ridge parts alternately formed in a circumferential direction;   inclined planes formed between the valley parts and the ridge parts raise the laundry from the valley parts during rotation of the pulsator; and   a movement changing member mounted at an upper part of each of the ridge parts to drop the laundry raised along the inclined planes to the valley parts.   
     
     
         15 . The washing machine according to  claim 14 , wherein the movement changing member comprises a roller rotated by friction with the laundry. 
     
     
         16 . A washing machine comprising:
 a cabinet;   a rotary tub rotatably mounted in the cabinet; and   a pulsator rotatably mounted at a lower part of the rotary tub, the pulsator having a lifter protruding from a top thereof to raise and lower laundry during rotation of the pulsator so that the laundry is washed in a wobbling fashion and a roller mounted at an upper end of the lifter.   
     
     
         17 . A pulsator for washing machines rotatably mounted at a rotary tub to generate a water current, comprising:
 valley parts and ridge parts alternately formed in a circumferential direction;   inclined planes formed between the valley parts and the ridge parts; and   a roller mounted at an upper part of each of the ridge parts, wherein   the roller extends from a center of the pulsator in a radial direction to rotate about a radial axis of the pulsator.   
     
     
         18 . A pulsator for washing machines rotatably mounted at a rotary tub to generate a water current, comprising:
 a lifter protruding from a top of the pulsator to raise laundry during rotation of the pulsator; and   a roller mounted at an upper end of the lifter to drop the laundry raised by the lifter.