Drum type washing machine

Abstract

Drum type washing machine including a tub fitted in a cabinet, and a pair of drums fitted in the tub to be rotatable in opposite directions, thereby permitting to obtain an excellent washing effect as an enfire surface of laundry is made to make uniform friction with the inner drum and the outer drum, and to prevent entangling of the laundry as the laundry is washing during the laundry back and forth the inner drum and the outer drum, alternately.

What is claimed is:  
     
         1 . A drum type washing machine comprising: 
 a tub fitted in a cabinet; and,    a pair of drums fitted in the tub to be rotatable in opposite directions.    
     
     
         2 . A drum type washing machine as claimed in  claim 1 , wherein the pair of drums includes; 
 an outer drum rotatably fitted in the tub, and    an inner drum rotatably fitted in the outer drum having a diameter and a length smaller than the outer drum, respectively.    
     
     
         3 . A drum type washing machine as claimed in  claim 2 , wherein the outer drum includes an inward ridge projected radially from a circumference of the outer drum at a position opposite to a fore end of the inner drum for maintaining sealing between the inner drum and the outer drum.  
     
     
         4 . A drum type washing machine as claimed in  claim 3 , further comprising sealing means for preventing infiltration of water into a gap between the ridge and the inner drum.  
     
     
         5 . A drum type washing machine as claimed in  claim 2 , wherein, the inner drum has a rear end connected to the rotor in a motor part by an inner drum shaft, there is a stator fixed to a rear end of a rear wall of the tub inside of the rotor, the outer drum has a rear end fixed to an outer drum shaft, and the outer drum shaft has a rotation force transmission device provided thereto for transmission of the rotation force of the inner drum shaft to the outer drum shaft.  
     
     
         6 . A drum type washing machine as claimed in  claim 5 , wherein the outer drum shaft is rotatably supported at an outer circumference thereof on a front bearing fitted an a fore end of a gear box housing formed in a rear wall of the tub, and the inner drum shaft is rotatably supported at an outer circumference thereof on a rear bearing fitted at a rear end of the bearing housing.  
     
     
         7 . A drum type washing machine as claimed in  claim 5 , wherein the rotation force transmission device includes; 
 a gear box fixed inside of the gear box housing having opened fore end and rear end for allowing the inner, and outer drum shafts to pass therethrough or be inserted therein,    a sun gear fitted coaxially with the inner drum shaft for interlocked rotation with the inner drum shaft,    a plurality of planetary gears for being rotated by receiving rotation force from the sun gear,    a shaft extension extended from the rear end of the outer drum shaft having an inner circumference with a gear part for engagement with the planetary gears,    a carrier having a rotation shaft in front of a base, which is a rotation center of the planetary gears, and an extension in rear of the base positioned between the inner drum shaft and a rear opening in the gear box,    first one way rotation means between an outside circumference of the inner drum shaft and an inside circumference of the outer drum shaft for permitting one way interlocked rotation of the inner, and outer drum shafts, and    second one way rotation means between an inside circumference of the rear end opening in the gear box and an outside circumference of the extension of the carrier for permitting one way rotation of the carrier.    
     
     
         8 . A drum type washing machine as claimed in  claim 7 , wherein the sun gear is formed as a unit with the inner drum shaft.  
     
     
         9 . A drum type washing machine as claimed in  claim 7 , wherein the planetary gear includes two gears having radiuses, and numbers of teeth, both different from each other fixed as one unit coaxially.  
     
     
         10 . A drum type washing machine as claimed in  claim 7 , wherein the carrier rotates in a direction the same with a rotation direction of the inner drum shaft centered on an axis of the inner drum shaft as the inner drum shaft rotates.  
     
     
         11 . A drum type washing machine as claimed in  claim 7 , wherein the first, and second one way rotation means is one way bearings.  
     
     
         12 . A drum type washing machine as claimed in  claim 7 , wherein there is an oilless bearing between the outside circumference of the inner drum shaft and the inside circumference of the extension of the carrier.  
     
     
         13 . A drum type washing machine as claimed in  claim 12 , further comprising sealing means between an outside circumference of the inner drum shaft in rear of the oilless bearing and an inside circumference of the extension of the carrier.  
     
     
         14 . A drum type washing machine as claimed in  claim 7 , wherein the first one way rotation means permits opposite direction rotation of the inner drum shaft and the outer drum shaft in washing, and holds the outer drum shaft so as to rotate in a direction the same with the inner drum shaft in spinning.  
     
     
         15 . A drum type washing machine as claimed in  claim 7 , wherein the second one way rotation means restricts such that the gear box and the carrier rotate in the same direction in washing, and permits opposite direction rotation of the gear box and the carrier in spinning.  
     
     
         16 . A drum type washing machine as claimed in  claim 7 , wherein the shaft extension has a diameter greater than a diameter of the outer drum shaft, and smaller than a diameter of the gear box.  
     
     
         17 . A drum type washing machine as claimed in  claim 2 , wherein the inner drum is rotated as the inner drum receives a driving force from a driving motor separately fitted to one side of the tub, the outer drum is fixed to the outer drum shaft at a rear end thereof, and the outer drum shaft is provided with a rotation transmission device for transmission of a rotation force from the inner drum shaft to the outer drum shaft.  
     
     
         18 . A drum type washing machine as claimed in  claim 17 , wherein a power transmission to the inner drum is made by a driving motor fitted in a lower part of the tub, a motor pulley coupled to the driving motor, a drum pulley coupled to the inner drum shaft, and belt means for transmitting the rotation force from the motor pulley to the drum pulley.  
     
     
         19 . A drum type washing machine as claimed in  claim 17 , wherein the tub includes a bearing housing formed as one unit therewith at a central part thereof having a front part and a rear part fitted with a front bearing and a rear bearing respectively, for supporting an outside circumference of the outer drum shaft.  
     
     
         20 . A drum type washing machine as claimed in  claim 17 , wherein, there is a gear box in rear of a rear wall of the tub for holding the rotation transmission device therein.  
     
     
         21 . A drum type washing machine as claimed in  claim 20 , wherein the gear box includes a flange formed along an outside circumference of a front part for fastening the gear box to the rear wall of the tub by fastening means.  
     
     
         22 . A drum type washing machine as claimed in  claim 21 , wherein the flange has a plurality of holes along a circumference for passing fastening means, the tub has fastening holes in the rear wall at positions corresponding to the holes in the flange.  
     
     
         23 . A drum type washing machine as claimed in  claim 1  or  2 , wherein the drums include a plurality of lifters elongated along an axis direction, and projected form an inside surface to a radial direction.  
     
     
         24 . A drum type washing machine as claimed in  claim 23 , wherein the lifter on the inside surface of the inner drum has a section becoming the smaller as it goes to a front part in an axis direction, and the lifter on the inside surface of the outer drum has a section becoming the smaller as it goes to a rear part in an axis direction.  
     
     
         25 . A drum type washing machine as claimed in  claim 23 , wherein the lifter has a triangular section.  
     
     
         26 . A drum type washing machine as claimed in  claim 23 , wherein the lifter has an “M” section, to form a groove in a top part in a radial direction.  
     
     
         27 . A drum type washing machine as claimed in  claim 23 , wherein the lifter on the inside surface of the inner drum has a helical form for moving the laundry and water in the drum forward (door side) along an axis direction as the inner drum rotates in washing, and the lifter on the inside surface of the outer drum has a helical form for moving the laundry and water in the drum backward along an axis direction as the outer drum rotates in washing.  
     
     
         28 . A drum type washing machine comprising: 
 an outer drum rotatably fitted in a tub, having a rear end an outer drum shaft fixed thereto, the outer drum shaft having a rear end coupled to a stator fixed to a rear end of a rear wall of the tub;    an inner drum rotatably fitted in the outer drum, having a rear end an inner drum shaft fixed thereto, the inner drum shaft having a rear end coupled to a rotor in the motor part;    a gear box housing extended in a rear direction from a front through hole formed in a central part in rear of a rear wall of the tub formed as one unit with the rear wall, to form a cavity, having a rear through hole in a rear end thereof;    a front bearing, and a rear bearing fitted in the front through hole and the rear through hole for rotatably supporting an outside circumference of the outer drum shaft and the outside circumference of the inner drum shaft, respectively; and,    a rotation force transmission device including a gear box fixed inside of the gear box housing having opened fore end and rear end for allowing the inner, and outer drum shaft to pass therethrough or be inserted therein, a sun gear fitted coaxially with the inner drum shaft for interlocked rotation with the inner drum shaft, a plurality of planetary gears for being rotated by receiving rotation force from the sun gear, a shaft extension extended from the rear end of the outer drum shaft having an inner circumference with a gear part for engagement with the planetary gears, a carrier having a rotation shaft in front of a base, which is a rotation center of the planetary gears, and an extension in rear of the base positioned between the inner drum shaft and a rear opening in the gear box, first one way rotation means between an outside circumference of the inner drum shaft and an inside circumference of the outer drum shaft for permitting one way interlocked rotation of the inner, and outer drum shafts, and second one way rotation means between an inside circumference of the rear end opening in the gear box and an outside circumference of the extension of the carrier for permitting one way rotation of the carrier.    
     
     
         29 . A drum type washing machine comprising: 
 an outer drum rotatably fitted in a tub, having a rear end an outer drum shaft fixed thereto, the outer drum shaft having a rear end passed through a central part of a rear wall of the tub to outside thereof;    a driving motor fitted in a lower part of the tub having a driving shaft coupled to a motor pulley;    an inner drum rotatably fitted in the outer drum, having a rear end an inner drum shaft fixed thereto, the inner drum shaft having a rear end coupled to a drum pulley for receiving a rotation force from the driving motor by means of belt means;    a gear box fastened to a rear side of the rear wall of the tub by fastening means, having openings in a front end, and a rear end for passing, or inserting the inner, and the outer drum shafts, and a cavity therein;    a front bearing, and a rear bearing fitted in a front part, and rear part of the bearing housing for rotatably supporting an outside circumference of the outer drum shaft; and,    a rotation force transmission device including a sun gear fitted coaxially with the inner drum shaft for interlocked rotation with the inner drum shaft, a plurality of planetary gears for being rotated by receiving rotation force from the sun gear, a shaft extension extended from the rear end of the outer drum shaft having an inner circumference with a gear part for engagement with the planetary gears, a carrier having a rotation shaft in front of a base, which is a rotation center of the planetary gears, and an extension in rear of the base positioned between the inner drum shaft and a rear opening in the gear box, first one way rotation means between an outside circumference of the inner drum shaft and an inside circumference of the outer drum shaft for permitting one way interlocked rotation of the inner, and outer drum shafts, and second one way rotation means between an inside circumference of the rear end opening in the gear box and an outside circumference of the extension of the carrier for permitting one way rotation of the carrier.